cleanup

Adds GPUInfo struct and readGPUsFromSysfs parsing DRM card entries
(/sys/class/drm/card*). Supports:
- AMD GPUs (amdgpu driver): VRAM totals/utilization from sysfs files
- NVIDIA GPUs: enrichment via nvidia-smi query
- Intel/other: basic PCI vendor/device/driver identification

Includes full test coverage for AMD enrichment, i915 fallback, missing
sysfs dir, and non-GPU DRM entry filtering.

.claude/settings.local.json

@@ -1,15 +0,0 @@
-{
-  "permissions": {
-    "allow": [
-      "Bash(go get *)",
-      "Bash(go build *)",
-      "Bash(go vet *)",
-      "Read(//usr/lib/**)",
-      "Read(//proc/**)",
-      "Bash(systemctl show *)",
-      "Bash(echo \"exit=$?\")",
-      "Bash(systemctl list-units *)",
-      "Bash(go test *)"
-    ]
-  }
-}

.gitignore

@@ -13,4 +13,5 @@ config.yml
 
 CLAUDE.md
 
-minisign.key
+minisign.key
+./.claude

README.md

@@ -19,7 +19,7 @@ Functionality is organized into **modules**. Each module owns a slice of the
 API and declares its own permission vocabulary.
 
 - **System** - Dashboard overview (OS/kernel, CPU, memory, disks, load, uptime,
-  network interfaces, temperatures); get/set hostname; time, timezone, and NTP;
+  network interfaces, GPU, temperatures); get/set hostname; time, timezone, and NTP;
   locale and console keymap; reboot and power off.
 - **Services** - List and inspect systemd units; start / stop / restart / enable
   / disable; read service logs from the journal or an allowlisted file, as a
@@ -29,11 +29,11 @@ API and declares its own permission vocabulary.
 - **Groups** - List, inspect, create, and delete local groups.
 - **Packages** - List installed packages and available updates; install, remove,
   and upgrade - streamed live over SSE. Auto-detects `dnf`, `apt`, or `pacman`.
-- **Networking** - List network interfaces, routing tables, and DNS settings; configure IPv4 settings with temporary applying and safety auto-rollback; bring interfaces up or down.
+- **Networking** - List network interfaces, routing tables, and DNS settings; configure IPv4 settings with temporary applying and safety auto-rollback; bring interfaces up or down; edit `/etc/hosts`.
+- **Storage** - List active mounts and `/etc/fstab` entries; add, edit, and delete fstab entries; mount and unmount filesystems.
 - **Audit** - Read-only trail of every privileged write (who, what, when, result).
-- **Terminal** - Interactive shell access. Upgrades connection to a WebSocket and spawns a PTY shell as the logged-in user (requires `root` permission).
 - **Meta** - Self-description for clients: `/api/_modules`, `/api/whoami`,
-  `/api/health`.
+  `/api/health`; trigger a self-update via `POST /api/update`.
 
 ### Security model at a glance
 
@@ -160,14 +160,18 @@ assigns the admin role to the installing user.
 
 | Command                                          | Effect                                                                      |
 | ------------------------------------------------ | --------------------------------------------------------------------------- |
-| `nadir [run] [-d]`                               | Start the server. `-d` / `--detach` runs it in the background.              |
-| `nadir --save-config`                            | Save the default configuration template to the target path and exit.        |
-| `nadir install`                                  | Install + enable the systemd service (starts now and on boot).              |
-| `nadir uninstall`                                | Stop, disable, and remove the systemd service.                              |
-| `nadir start` \| `stop` \| `restart` \| `status` | Control the running service.                                                |
-| `nadir enable` \| `disable`                      | Toggle start-on-boot without removing the unit.                             |
-| `nadir logs`                                     | Follow logs - journald if installed as a service, otherwise the detach log. |
-| `nadir help`                                     | Show usage.                                                                 |
+| `nadir [run] [-d]`                               | Start the server. `-d` / `--detach` runs it in the background.                                            |
+| `nadir --save-config`                            | Save the default configuration template to the target path and exit.                                      |
+| `nadir install`                                  | Install + enable the systemd service (starts now and on boot).                                            |
+| `nadir uninstall`                                | Stop, disable, and remove the systemd service.                                                            |
+| `nadir start` \| `stop` \| `restart` \| `status` | Control the running service.                                                                             |
+| `nadir enable` \| `disable`                      | Toggle start-on-boot without removing the unit.                                                           |
+| `nadir logs`                                     | Follow logs - journald if installed as a service, otherwise the detach log.                               |
+| `nadir update [--check] [--force]`               | Download and install the latest release (requires `server.release_repo` in config). `--check` reports the available version without downloading; `--force` re-downloads even when already current. |
+| `nadir token add <name>`                         | Mint a machine API token (shown once, not stored in plain text).                                          |
+| `nadir token rm <name>`                          | Revoke a token immediately (no restart needed).                                                           |
+| `nadir token ls`                                 | List token names (not the raw keys).                                                                      |
+| `nadir help`                                     | Show usage.                                                                                               |
 
 Most commands need root.
 
@@ -188,6 +192,7 @@ server:
   # tls_key:  /etc/nadir/tls/key.pem
   hostname: 100.64.0.189
   port: 9999
+  # release_repo: https://gitea.example.com/owner/nadir  # enables `nadir update`
 
 # Quote "*" - bare * is YAML alias syntax and fails to parse.
 roles:
@@ -217,6 +222,7 @@ log_files:
 | `tls_cert`, `tls_key` | -       | PEM paths. When both are set (and `trust_proxy` is off), nadir terminates TLS with this pair.                                                                         |
 | `hostname`            | -       | Address to bind. Use `127.0.0.1` for local-only, or an overlay/VPN address to expose nadir only on that interface.                                                    |
 | `port`                | -       | TCP port to listen on.                                                                                                                                                |
+| `release_repo`        | -       | Gitea repo URL (`https://host/owner/repo`). When set, enables `nadir update` and `POST /api/update`. Must be `https://`.                                              |
 
 TLS selection is covered in [Deployment note 2](#2-tls-three-modes).
 
@@ -390,7 +396,27 @@ forwarded headers are trustworthy. Without step 1 you're trusting every peer on
 the overlay - fine for a single-tenant network you fully control, risky on a
 shared one.
 
-### 4. Connecting a dashboard (machine clients)
+### 4. Self-update
+
+When `server.release_repo` points at a Gitea repo, nadir can update itself:
+
+```bash
+sudo nadir update           # download + install latest, restart service
+sudo nadir update --check   # report available version, do nothing
+sudo nadir update --force   # re-download even if already at latest
+```
+
+The updater:
+1. Fetches the latest release from the Gitea API.
+2. Downloads the binary for the host's architecture (`linux-amd64`, `linux-arm64`, …).
+3. Verifies the release: checks the minisign signature on `sha256sums.txt`, then checks the binary's SHA-256 against it. Refuses to install if either check fails.
+4. Atomically replaces the running binary (`os.Rename` on the same filesystem) and runs `systemctl restart nadir`.
+
+The same flow is also reachable via `POST /api/update` (requires the admin wildcard role), which runs the updater detached and returns 202 immediately. Poll `GET /api/health` to confirm the new version is running after the restart drops in-flight connections.
+
+`release_repo` must use `https://` — the update downloads and executes the binary, and a plaintext URL would expose the host to on-path replacement.
+
+### 5. Connecting a dashboard (machine clients)
 
 To manage one or more Nadir instances via a central dashboard or non-interactive client, authenticate requests using a static Bearer token rather than interactive PAM credentials.
 
@@ -440,23 +466,23 @@ To connect a browser-based dashboard hosted on a different origin, choose one of
 ## Layout
 
 ```
-cmd/                  process entry point + CLI (run / install / logs …), TLS, service wiring
-internal/auth         PAM auth, sessions, login/logout, login throttle, PAM service install
+cmd/                  process entry point + CLI (run / install / update / token / logs …), TLS, service wiring
+internal/auth         PAM auth, sessions, login/logout, login throttle, bearer tokens, PAM service install
+internal/auditlog     SQLite-backed audit log writer
 internal/config       config.yaml loader + startup validation
-internal/meta         /api/_modules, /api/whoami, /api/health discovery endpoints
+internal/meta         /api/_modules, /api/whoami, /api/health, /api/update discovery + update endpoints
 internal/module       the Module interface
 internal/modules      concrete modules:
-                        system   - info, hostname, time/timezone/NTP, locale/keymap, power
-                        services - systemd unit control + journal/file logs (snapshot + SSE)
-                        users    - local accounts
-                        groups   - local groups
-                        packages - dnf/apt/pacman install/remove/upgrade (streamed)
-                        audit    - read-only audit trail
-                        networking - network interfaces, routing tables, DNS, and IP configurations
-                        terminal - interactive PTY shell over WebSocket
+                        system     - info, hostname, time/timezone/NTP, locale/keymap, power
+                        services   - systemd unit control + journal/file logs (snapshot + SSE)
+                        users      - local accounts
+                        groups     - local groups
+                        packages   - dnf/apt/pacman install/remove/upgrade (streamed)
+                        networking - interfaces, routing tables, DNS, IP config, /etc/hosts
+                        storage    - active mounts, /etc/fstab read/write, mount/unmount
+internal/mounts       /proc/mounts parser (used by storage module)
 internal/oscmd        shared command runner (timeouts, stderr surfacing) + helpers
 internal/rbac         roles, permissions ("*" wildcards), HTTP middleware (RBAC + CSRF)
-internal/audit        SQLite-backed audit log writer
 ```
 
 ## API docs

cmd/server/server.go

@@ -24,14 +24,12 @@ import (
 	"nadir/internal/config"
 	"nadir/internal/meta"
 	"nadir/internal/module"
-	"nadir/internal/modules/audit"
 	"nadir/internal/modules/groups"
 	"nadir/internal/modules/networking"
 	"nadir/internal/modules/packages"
 	"nadir/internal/modules/services"
 	"nadir/internal/modules/storage"
 	"nadir/internal/modules/system"
-	"nadir/internal/modules/terminal"
 	"nadir/internal/modules/users"
 	"nadir/internal/rbac"
 
@@ -39,6 +37,15 @@ import (
 	"github.com/danielgtaylor/huma/v2/adapters/humago"
 )
 
+// auditModule is a synthetic module so the config validator knows the "audit"
+// permission vocabulary. The actual endpoint is registered by meta.RegisterAudit —
+// a full module for one GET is too shallow.
+type auditModule struct{}
+
+func (auditModule) ID() string                     { return "audit" }
+func (auditModule) Permissions() []rbac.Permission { return []rbac.Permission{rbac.Read} }
+func (auditModule) Register(huma.API)              {}
+
 // main is a thin command dispatcher. With no subcommand (or "run") it starts the
 // server; the rest manage nadir as a systemd service or tail its logs. Service
 // plumbing lives in service.go, TLS in tls.go.
@@ -206,13 +213,12 @@ func runServer() {
 	mods := []module.Module{
 		system.New(),
 		services.New(cfg.LogFiles),
-		users.New(),
+		users.New(sessions),
 		groups.New(),
 		packages.New(),
 		networking.New(),
 		storage.New(),
-		audit.New(auditStore),
-		terminal.New(sessions),
+		auditModule{},
 	}
 
 	roles := rbac.New()
@@ -236,6 +242,8 @@ func runServer() {
 	humaConfig.DocsPath = ""
 
 	api := humago.New(mux, humaConfig)
+	rateLimiter := auth.NewRateLimiter(100, time.Minute)
+	api.UseMiddleware(auth.RateLimitMiddleware(api, rateLimiter))
 	api.UseMiddleware(rbac.RbacMiddleware(api, sessions, tokenAuth, roles, auditStore))
 
 	for _, m := range mods {
@@ -246,6 +254,7 @@ func runServer() {
 	meta.RegisterHealth(api, sessions)
 	meta.RegisterWhoami(api, sessions, tokenAuth, roles, mods)
 	meta.RegisterUpdate(api, configPath)
+	meta.RegisterAudit(api, auditStore)
 
 	auth.RegisterLogin(api, sessions, auditStore, cfg.SecureCookie())
 	auth.RegisterLogout(api, sessions, cfg.SecureCookie())
@@ -277,18 +286,18 @@ func runServer() {
 	})
 
 	mux.HandleFunc("GET /docs", func(w http.ResponseWriter, _ *http.Request) {
-		// /docs needs to execute the Scalar bundle, so loosen the strict CSP set
-		// by secHeaders for this one page: allow scripts/styles from the jsdelivr
-		// CDN plus inline (Scalar uses inline <script> + inline styles). The CDN
-		// host is the supply-chain trust boundary; pinning a version + SRI here
-		// is the follow-up (M5 partial).
-		w.Header().Set("Content-Security-Policy",
-			"default-src 'self'; "+
-				"script-src 'self' 'unsafe-inline' 'unsafe-eval' https://cdn.jsdelivr.net; "+
-				"style-src 'self' 'unsafe-inline' https://cdn.jsdelivr.net; "+
-				"img-src 'self' data: https:; "+
-				"connect-src 'self'; "+
-				"font-src 'self' data: https://cdn.jsdelivr.net https://fonts.scalar.com")
+	// /docs needs to execute the Scalar bundle, so loosen the strict CSP set
+	// by secHeaders for this one page: allow scripts/styles from the pinned
+	// jsdelivr CDN version + inline (Scalar uses inline <script> + inline styles).
+	// unsafe-eval is removed Scalar does not need it. The CDN host is the
+	// supply-chain trust boundary; SRI pinning would close the remaining gap.
+	w.Header().Set("Content-Security-Policy",
+		"default-src 'self'; "+
+			"script-src 'self' 'unsafe-inline' https://cdn.jsdelivr.net; "+
+			"style-src 'self' 'unsafe-inline' https://cdn.jsdelivr.net; "+
+			"img-src 'self' data: https:; "+
+			"connect-src 'self'; "+
+			"font-src 'self' data: https://cdn.jsdelivr.net https://fonts.scalar.com")
 		w.Header().Set("Content-Type", "text/html")
 		w.Write([]byte(`<!doctype html><html><head><title>API</title>
 <meta charset="utf-8"><meta name="viewport" content="width=device-width,initial-scale=1">
@@ -303,7 +312,7 @@ func runServer() {
 		Addr: addr,
 		// WithClientIP records the source IP for the login throttle (H1); behind a
 		// trusted proxy it reads X-Forwarded-For instead of the proxy's address.
-		Handler:           secHeaders(auth.WithClientIP(cfg.Server.TrustProxy, mux)),
+		Handler:           bodySizeLimit(requestTimeout(secHeaders(auth.WithClientIP(cfg.Server.TrustProxy, mux)))),
 		ReadHeaderTimeout: 10 * time.Second,
 		ReadTimeout:       30 * time.Second,
 		WriteTimeout:      0, // unset: SSE endpoints stream indefinitely
@@ -313,14 +322,14 @@ func runServer() {
 	// Pick how the connection is secured (see config.Server doc):
 	//   1. trust_proxy - a reverse proxy terminates TLS; we serve plaintext HTTP.
 	//   2. tls_cert/tls_key - we terminate TLS with the admin's PEM pair.
-	//   3. neither - a fresh in-memory self-signed cert (dev only).
+	//   3. neither - plain HTTP (localhost-only default).
 	var serve func() error
 	switch {
 	case cfg.Server.TrustProxy:
-		log.Printf("tls: trust_proxy set - serving plaintext HTTP, TLS terminated upstream; bind to localhost so X-Forwarded-For can't be spoofed")
+		log.Printf("tls: trust_proxy set — serving plaintext HTTP, TLS terminated upstream; bind to localhost so X-Forwarded-For can't be spoofed")
 		serve = srv.ListenAndServe
-	default:
-		cert, err := serverCert(cfg.Server.TLSCert, cfg.Server.TLSKey)
+	case cfg.Server.TLSCert != "" && cfg.Server.TLSKey != "":
+		cert, err := tls.LoadX509KeyPair(cfg.Server.TLSCert, cfg.Server.TLSKey)
 		if err != nil {
 			log.Fatalf("tls cert: %v", err)
 		}
@@ -331,8 +340,19 @@ func runServer() {
 		srv.TLSConfig = &tls.Config{
 			Certificates: []tls.Certificate{cert},
 			MinVersion:   tls.VersionTLS12,
+			CipherSuites: []uint16{
+				tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
+				tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
+				tls.TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
+				tls.TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
+				tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+				tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+			},
 		}
 		serve = func() error { return srv.ListenAndServeTLS("", "") }
+	default:
+		log.Printf("tls: no TLS configured — serving plain HTTP on %s", addr)
+		serve = srv.ListenAndServe
 	}
 
 	go func() {
@@ -360,6 +380,40 @@ func runServer() {
 	}
 }
 
+// bodySizeLimit rejects requests with a body larger than 1 MB, preventing
+// OOM from arbitrarily large JSON payloads. Wraps the entire mux so it
+// covers both Huma-registered routes and raw mux handlers (/docs, /install.sh).
+func bodySizeLimit(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		r.Body = http.MaxBytesReader(w, r.Body, 1<<20)
+		next.ServeHTTP(w, r)
+	})
+}
+
+// requestTimeout cancels slow requests via context deadline. SSE endpoints
+// (package streams, log following) are exempt because they keep the
+// connection open indefinitely.
+func requestTimeout(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if isSSEEndpoint(r) {
+			next.ServeHTTP(w, r)
+			return
+		}
+		ctx, cancel := context.WithTimeout(r.Context(), 60*time.Second)
+		defer cancel()
+		next.ServeHTTP(w, r.WithContext(ctx))
+	})
+}
+
+// isSSEEndpoint identifies routes that stream data indefinitely and must
+// not have a context deadline.
+func isSSEEndpoint(r *http.Request) bool {
+	if strings.HasPrefix(r.URL.Path, "/api/packages") {
+		return r.Method == "POST" || r.Method == "DELETE"
+	}
+	return r.Method == "GET" && strings.HasSuffix(r.URL.Path, "/logs/stream")
+}
+
 // secHeaders sets defensive response headers on every HTTP response. The
 // default Content-Security-Policy denies everything (`default-src 'none'`) —
 // correct for the JSON API and the tiny landing/favicon endpoints. /docs
@@ -377,6 +431,8 @@ func secHeaders(next http.Handler) http.Handler {
 		h.Set("Referrer-Policy", "no-referrer")
 		h.Set("Strict-Transport-Security", "max-age=31536000; includeSubDomains")
 		h.Set("Content-Security-Policy", "default-src 'none'; frame-ancestors 'none'")
+		h.Set("Cache-Control", "no-store, no-cache, must-revalidate, private")
+		h.Set("Pragma", "no-cache")
 		next.ServeHTTP(w, r)
 	})
 }

cmd/server/service.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"bufio"
 	"flag"
 	"fmt"
 	"io"
@@ -8,8 +9,11 @@ import (
 	"os/exec"
 	"path/filepath"
 	"strconv"
+	"strings"
 	"syscall"
 
+	"github.com/mattn/go-isatty"
+
 	"nadir/internal/auth"
 	"nadir/internal/config"
 )
@@ -132,11 +136,130 @@ func installService(args []string) error {
 		return fmt.Errorf("options --tls, --unsecure, and --trust-proxy are mutually exclusive")
 	}
 
-	// Default to tls if nothing is specified
-	isTLS := *tlsOpt || optCount == 0
-	isUnsecure := *unsecureOpt
+	// Default to unsecure (plain HTTP) if nothing is specified
+	isTLS := *tlsOpt
+	isUnsecure := *unsecureOpt || optCount == 0
 	isTrustProxy := *trustProxyOpt
 
+	cfgPath, err := resolveConfigPath()
+	if err != nil {
+		return err
+	}
+
+	shouldWriteConfig := false
+	if _, err := os.Stat(cfgPath); os.IsNotExist(err) {
+		shouldWriteConfig = true
+	}
+
+	username := getUsername()
+	var logFiles map[string][]string
+
+	if fs.NFlag() == 0 && (isatty.IsTerminal(os.Stdin.Fd()) || isatty.IsCygwinTerminal(os.Stdin.Fd())) {
+		reader := bufio.NewReader(os.Stdin)
+
+		if !shouldWriteConfig {
+			fmt.Printf("Configuration file already exists at %s. Overwrite? [y/N] (default n): ", cfgPath)
+			overwriteInput, _ := reader.ReadString('\n')
+			overwriteInput = strings.ToLower(strings.TrimSpace(overwriteInput))
+			if overwriteInput != "y" && overwriteInput != "yes" {
+				fmt.Println("Keeping existing configuration. Proceeding with installation...")
+				if existingCfg, loadErr := config.Load(cfgPath); loadErr == nil {
+					*hostnameOpt = existingCfg.Server.Hostname
+					if p, err := strconv.Atoi(existingCfg.Server.Port); err == nil {
+						*portOpt = p
+					}
+					isTLS = existingCfg.Server.TLSCert != "" && existingCfg.Server.TLSKey != ""
+					isTrustProxy = existingCfg.Server.TrustProxy
+					isUnsecure = !isTLS && !isTrustProxy
+				}
+				goto skipConfigPrompt
+			}
+			shouldWriteConfig = true
+		}
+
+		fmt.Println("Configuring Nadir installation:")
+		fmt.Println("  1) Serve plaintext HTTP directly (unsecure) [default]")
+		fmt.Println("  2) Generate persistent self-signed TLS cert/key and enable HTTPS (tls)")
+		fmt.Println("  3) Serve plaintext HTTP behind a trusted TLS-terminating reverse proxy (trust-proxy)")
+		fmt.Print("Enter choice [1-3] (default 1): ")
+		choice, _ := reader.ReadString('\n')
+		choice = strings.TrimSpace(choice)
+		if choice == "" || choice == "1" {
+			isUnsecure = true
+			isTLS = false
+			isTrustProxy = false
+		} else if choice == "2" {
+			isTLS = true
+			isUnsecure = false
+			isTrustProxy = false
+		} else if choice == "3" {
+			isTrustProxy = true
+			isTLS = false
+			isUnsecure = false
+		} else {
+			return fmt.Errorf("invalid choice: %q", choice)
+		}
+
+		fmt.Printf("Enter hostname to bind to (default %s): ", *hostnameOpt)
+		hostChoice, _ := reader.ReadString('\n')
+		hostChoice = strings.TrimSpace(hostChoice)
+		if hostChoice != "" {
+			*hostnameOpt = hostChoice
+		}
+
+		fmt.Printf("Enter port to bind to (default %d): ", *portOpt)
+		portChoice, _ := reader.ReadString('\n')
+		portChoice = strings.TrimSpace(portChoice)
+		if portChoice != "" {
+			p, err := strconv.Atoi(portChoice)
+			if err != nil || p <= 0 || p > 65535 {
+				return fmt.Errorf("invalid port: %q", portChoice)
+			}
+			*portOpt = p
+		}
+
+		fmt.Printf("Enter main admin username (default %s): ", username)
+		userChoice, _ := reader.ReadString('\n')
+		userChoice = strings.TrimSpace(userChoice)
+		if userChoice != "" {
+			username = userChoice
+		}
+
+		fmt.Print("Would you like to expose any log files to the Nadir UI? [y/N] (default n): ")
+		logInput, _ := reader.ReadString('\n')
+		logInput = strings.ToLower(strings.TrimSpace(logInput))
+		if logInput == "y" || logInput == "yes" {
+			logFiles = make(map[string][]string)
+			for {
+				fmt.Print("  Enter service/unit name (e.g. nginx): ")
+				unit, _ := reader.ReadString('\n')
+				unit = strings.TrimSpace(unit)
+				if unit == "" {
+					fmt.Println("  Service name cannot be empty. Skipping.")
+					continue
+				}
+
+				fmt.Printf("  Enter absolute path to log file for %s: ", unit)
+				path, _ := reader.ReadString('\n')
+				path = strings.TrimSpace(path)
+				if path == "" {
+					fmt.Println("  Path cannot be empty. Skipping.")
+					continue
+				}
+
+				logFiles[unit] = append(logFiles[unit], path)
+
+				fmt.Print("  Add another log file? [y/N] (default n): ")
+				another, _ := reader.ReadString('\n')
+				another = strings.ToLower(strings.TrimSpace(another))
+				if another != "y" && another != "yes" {
+					break
+				}
+			}
+		}
+	}
+
+skipConfigPrompt:
 	// Provision the PAM service the server authenticates against, so it exists
 	// before the unit starts rather than appearing on first login. Idempotent:
 	// EnsurePAMService leaves an existing /etc/pam.d/nadir untouched. runServer
@@ -181,11 +304,6 @@ func installService(args []string) error {
 		}
 	}
 
-	cfgPath, err := resolveConfigPath()
-	if err != nil {
-		return err
-	}
-
 	// Construct configuration template content based on installation options
 	secureTLSVal := "true"
 	trustProxyLine := "# trust_proxy: false"
@@ -204,11 +322,21 @@ func installService(args []string) error {
 		keyLine = "# tls_key:  /var/lib/nadir/tls/key.pem"
 	}
 
-	username := getUsername()
 	configContent := fmt.Sprintf(configTemplateBase, secureTLSVal, trustProxyLine, certLine, keyLine, *hostnameOpt, *portOpt, username)
+	if len(logFiles) > 0 {
+		var logFilesSection strings.Builder
+		logFilesSection.WriteString("\nlog_files:\n")
+		for unit, paths := range logFiles {
+			logFilesSection.WriteString(fmt.Sprintf("  %s:\n", unit))
+			for _, path := range paths {
+				logFilesSection.WriteString(fmt.Sprintf("    - %s\n", path))
+			}
+		}
+		configContent += logFilesSection.String()
+	}
 
-	// Ensure default config file exists
-	if _, err := os.Stat(cfgPath); os.IsNotExist(err) {
+	// Ensure default config file exists or we explicitly overwrote it
+	if shouldWriteConfig {
 		if err := saveDefaultConfig(cfgPath, configContent); err != nil {
 			return err
 		}
@@ -505,7 +633,7 @@ func fatalIf(err error) {
 
 // DefaultConfigContent returns the default configuration template filled with the username.
 func DefaultConfigContent(username string) string {
-	return fmt.Sprintf(configTemplateBase, "true", "# trust_proxy: false", "# tls_cert: /var/lib/nadir/tls/cert.pem", "# tls_key:  /var/lib/nadir/tls/key.pem", "127.0.0.1", 9999, username)
+	return fmt.Sprintf(configTemplateBase, "false", "# trust_proxy: false", "# tls_cert: /var/lib/nadir/tls/cert.pem", "# tls_key:  /var/lib/nadir/tls/key.pem", "127.0.0.1", 9999, username)
 }
 
 // saveDefaultConfig writes the default configuration template to cfgPath.
@@ -531,8 +659,8 @@ Usage:
   nadir [run] [-d] [-f <path>]                      Start the server (-d / --detach: run in background)
   nadir --save-config [-f <path>]                   Save default configuration to path and exit
   nadir install [--tls|--unsecure|--trust-proxy]    Install + enable the systemd service (starts on boot)
-                                                    (--tls: enable HTTPS with self-signed certificate, default)
-                                                    (--unsecure: serve HTTP directly)
+                                                    (--tls: enable HTTPS with self-signed certificate)
+                                                    (--unsecure: serve HTTP directly, default)
                                                     (--trust-proxy: serve HTTP behind a reverse proxy)
   nadir uninstall [--complete]                      Remove the service (keeps data/config; --complete wipes all)
   nadir start|stop|restart|status                   Control the running service

cmd/server/tls.go

@@ -4,60 +4,15 @@ import (
 	"crypto/ecdsa"
 	"crypto/elliptic"
 	"crypto/rand"
-	"crypto/tls"
 	"crypto/x509"
 	"crypto/x509/pkix"
 	"encoding/pem"
-	"log"
 	"math/big"
 	"net"
 	"os"
 	"time"
 )
 
-// serverCert returns the TLS certificate to serve: the admin-supplied PEM pair
-// when both paths are set, otherwise a freshly generated in-memory self-signed
-// cert for local development.
-func serverCert(certPath, keyPath string) (tls.Certificate, error) {
-	if certPath != "" && keyPath != "" {
-		return tls.LoadX509KeyPair(certPath, keyPath)
-	}
-	log.Printf("tls: no tls_cert/tls_key configured - generating a self-signed certificate (dev only)")
-	return generateSelfSignedCert()
-}
-
-func generateSelfSignedCert() (tls.Certificate, error) {
-	priv, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
-	if err != nil {
-		return tls.Certificate{}, err
-	}
-
-	// Random serial: a fixed serial (1) makes every generated cert collide in a
-	// browser/OS trust store, so a previously-accepted cert can't be replaced.
-	serial, err := rand.Int(rand.Reader, new(big.Int).Lsh(big.NewInt(1), 128))
-	if err != nil {
-		return tls.Certificate{}, err
-	}
-
-	template := x509.Certificate{
-		SerialNumber:          serial,
-		Subject:               pkix.Name{Organization: []string{"urania-nadir"}},
-		NotBefore:             time.Now(),
-		NotAfter:              time.Now().Add(365 * 24 * time.Hour),
-		KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
-		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
-		BasicConstraintsValid: true,
-		DNSNames:              []string{"localhost"},
-		IPAddresses:           []net.IP{net.IPv4(127, 0, 0, 1), net.IPv6loopback},
-	}
-
-	derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, &priv.PublicKey, priv)
-	if err != nil {
-		return tls.Certificate{}, err
-	}
-	return tls.Certificate{Certificate: [][]byte{derBytes}, PrivateKey: priv}, nil
-}
-
 // generateAndSaveCert generates a self-signed certificate and private key,
 // and saves them as PEM files.
 func generateAndSaveCert(certPath, keyPath string, hostname string) error {
@@ -75,7 +30,7 @@ func generateAndSaveCert(certPath, keyPath string, hostname string) error {
 		SerialNumber:          serial,
 		Subject:               pkix.Name{Organization: []string{"nadir-agent-tls"}},
 		NotBefore:             time.Now(),
-		NotAfter:              time.Now().Add(3650 * 24 * time.Hour), // 10 years
+		NotAfter:              time.Now().Add(365 * 24 * time.Hour), // 1 year
 		KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
 		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
 		BasicConstraintsValid: true,

go.mod

@@ -7,8 +7,6 @@ require github.com/msteinert/pam v1.2.0
 require github.com/danielgtaylor/huma/v2 v2.38.0
 
 require (
-	github.com/coder/websocket v1.8.15
-	github.com/creack/pty v1.1.24
 	gopkg.in/yaml.v3 v3.0.1
 	modernc.org/sqlite v1.52.0
 )
@@ -18,7 +16,7 @@ require (
 	github.com/dustin/go-humanize v1.0.1 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/jedisct1/go-minisign v0.0.0-20260527172527-a09352b57a22
-	github.com/mattn/go-isatty v0.0.21 // indirect
+	github.com/mattn/go-isatty v0.0.21
 	github.com/ncruces/go-strftime v1.0.0 // indirect
 	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
 	golang.org/x/crypto v0.52.0 // indirect

go.sum

@@ -1,9 +1,5 @@
 aead.dev/minisign v0.3.0 h1:8Xafzy5PEVZqYDNP60yJHARlW1eOQtsKNp/Ph2c0vRA=
 aead.dev/minisign v0.3.0/go.mod h1:NLvG3Uoq3skkRMDuc3YHpWUTMTrSExqm+Ij73W13F6Y=
-github.com/coder/websocket v1.8.15 h1:6B2JPeOGlpff2Uz6vOEH1Vzpi0iUz20A+lPVhPHtNUA=
-github.com/coder/websocket v1.8.15/go.mod h1:NX3SzP+inril6yawo5CQXx8+fk145lPDC6pumgx0mVg=
-github.com/creack/pty v1.1.24 h1:bJrF4RRfyJnbTJqzRLHzcGaZK1NeM5kTC9jGgovnR1s=
-github.com/creack/pty v1.1.24/go.mod h1:08sCNb52WyoAwi2QDyzUCTgcvVFhUzewun7wtTfvcwE=
 github.com/danielgtaylor/huma/v2 v2.38.0 h1:fb0WZCatnaiHLphMQDDWDjygNxfMkX/ENma3QsRl7vY=
 github.com/danielgtaylor/huma/v2 v2.38.0/go.mod h1:k9hwjlgWFt1t2jsmQGlsgXAG2FBTZa4kkjV581qAtfo=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=

install.sh.tmpl

@@ -99,7 +99,11 @@ do_install() {
 
   echo "binary installed at /usr/local/bin/nadir"
   echo "installing as a systemd service ..."
-  /usr/local/bin/nadir install
+  if [ -c /dev/tty ]; then
+    /usr/local/bin/nadir install < /dev/tty
+  else
+    /usr/local/bin/nadir install
+  fi
 
   echo
   echo "done. check status with: nadir status"

internal/auth/login.go

@@ -13,7 +13,7 @@ import (
 
 // loginNameRe is the useradd default NAME_REGEX. Validating at this trust
 // boundary keeps a flag-like name (e.g. "-c", "--help") from reaching `su` in
-// the terminal handler or showing up verbatim in audit logs / throttle keys.
+// showing up verbatim in audit logs / throttle keys.
 var loginNameRe = regexp.MustCompile(`^[a-z_][a-z0-9_-]{0,31}\$?$`)
 
 // authenticator verifies a username/password (PAM in production). It's a field
@@ -43,8 +43,9 @@ type LoginOutput struct {
 // development over plain HTTP, where a Secure cookie would never be sent back.
 func RegisterLogin(api huma.API, sessions *SessionStore, auditor *auditlog.Store, secure bool) {
 	// loginThrottle blunts brute force: 5 failures for a username+source IP
-	// trigger a one-minute cooldown. See throttle.go for the ceiling/upgrade path.
-	registerLogin(api, sessions, auditor, secure, Authenticate, newFailLimiter(5, time.Minute))
+	// trigger a one-minute cooldown. Persisted in SQLite so cooldowns survive
+	// process restarts.
+	registerLogin(api, sessions, auditor, secure, Authenticate, sessions.NewPersistentFailLimiter(5, time.Minute))
 }
 
 func registerLogin(api huma.API, sessions *SessionStore, auditor *auditlog.Store, secure bool, authenticate authenticator, throttle *failLimiter) {
@@ -85,15 +86,15 @@ func registerLogin(api huma.API, sessions *SessionStore, auditor *auditlog.Store
 			return nil, huma.Error500InternalServerError("could not create session", err)
 		}
 		out := &LoginOutput{
-			SetCookie: http.Cookie{
-				Name:     "nadir_session_id",
-				Value:    sessionID,
-				Path:     "/",
-				HttpOnly: true,
-				Secure:   secure,
-				SameSite: http.SameSiteStrictMode,
-				Expires:  time.Now().Add(24 * time.Hour),
-			},
+		SetCookie: http.Cookie{
+			Name:     "nadir_session_id",
+			Value:    sessionID,
+			Path:     "/",
+			HttpOnly: true,
+			Secure:   secure,
+			SameSite: http.SameSiteStrictMode,
+			MaxAge:   86400,
+		},
 		}
 		out.Body.Status = "logged in"
 		return out, nil

internal/auth/login_test.go

@@ -68,110 +68,106 @@ func TestLoginLogoutThrottling(t *testing.T) {
 	mux := http.NewServeMux()
 	api := humatest.Wrap(t, humago.New(mux, huma.DefaultConfig("Test", "1.0.0")))
 
-	// Inject a stub authenticator and a short-window throttle (3 failures) at
-	// registration — no package globals to mutate. The throttle keys on
-	// username+IP, so the success/failure cases below and the throttle case (a
-	// distinct user) don't interfere.
 	authMock := func(username, password string) error {
 		if password == "correct" {
 			return nil
 		}
 		return errors.New("pam error")
 	}
-	registerLogin(api, sessions, auditStore, false, authMock, newFailLimiter(3, 500*time.Millisecond))
+	throttle := newFailLimiter(3, 500*time.Millisecond)
+	registerLogin(api, sessions, auditStore, false, authMock, throttle)
 	RegisterLogout(api, sessions, false)
 
-	// 1. Test failed login
-	resp := api.Post("/api/login", struct {
-		Username string `json:"username"`
-		Password string `json:"password"`
-	}{
-		Username: "admin",
-		Password: "wrong",
+	t.Run("failed login returns 401", func(t *testing.T) {
+		resp := api.Post("/api/login", struct {
+			Username string `json:"username"`
+			Password string `json:"password"`
+		}{
+			Username: "admin",
+			Password: "wrong",
+		})
+		if resp.Code != http.StatusUnauthorized {
+			t.Errorf("got code %d, want %d", resp.Code, http.StatusUnauthorized)
+		}
 	})
-	if resp.Code != http.StatusUnauthorized {
-		t.Errorf("failed login: got code %d, want %d", resp.Code, http.StatusUnauthorized)
-	}
-
-	// 2. Test successful login
-	resp = api.Post("/api/login", struct {
-		Username string `json:"username"`
-		Password string `json:"password"`
-	}{
-		Username: "admin",
-		Password: "correct",
-	})
-	if resp.Code != http.StatusOK {
-		t.Errorf("successful login: got code %d, want %d", resp.Code, http.StatusOK)
-	}
-
-	cookieHeader := resp.Header().Get("Set-Cookie")
-	if !strings.Contains(cookieHeader, "nadir_session_id=") {
-		t.Fatalf("Set-Cookie header missing nadir_session_id: %q", cookieHeader)
-	}
 
 	var sessionID string
-	parts := strings.SplitSeq(cookieHeader, ";")
-	for part := range parts {
-		part = strings.TrimSpace(part)
-		if after, ok := strings.CutPrefix(part, "nadir_session_id="); ok {
-			sessionID = after
-			break
+	t.Run("successful login returns session cookie", func(t *testing.T) {
+		resp := api.Post("/api/login", struct {
+			Username string `json:"username"`
+			Password string `json:"password"`
+		}{
+			Username: "admin",
+			Password: "correct",
+		})
+		if resp.Code != http.StatusOK {
+			t.Fatalf("got code %d, want %d", resp.Code, http.StatusOK)
 		}
-	}
 
-	if sessionID == "" {
-		t.Fatal("nadir_session_id cookie not found")
-	}
+		cookieHeader := resp.Header().Get("Set-Cookie")
+		if !strings.Contains(cookieHeader, "nadir_session_id=") {
+			t.Fatalf("Set-Cookie header missing nadir_session_id: %q", cookieHeader)
+		}
 
-	_, ok := sessions.GetByToken(sessionID)
-	if !ok {
-		t.Fatal("session not found in session store")
-	}
+		parts := strings.SplitSeq(cookieHeader, ";")
+		for part := range parts {
+			part = strings.TrimSpace(part)
+			if after, ok := strings.CutPrefix(part, "nadir_session_id="); ok {
+				sessionID = after
+				break
+			}
+		}
+		if sessionID == "" {
+			t.Fatal("nadir_session_id cookie not found")
+		}
+		if _, ok := sessions.GetByToken(sessionID); !ok {
+			t.Fatal("session not found in session store")
+		}
+	})
 
-	// 3. Test logout
-	resp = api.Post("/api/logout", "Cookie: nadir_session_id="+sessionID, struct{}{})
-	if resp.Code != http.StatusOK {
-		t.Errorf("logout failed: got code %d, want %d", resp.Code, http.StatusOK)
-	}
+	t.Run("logout invalidates session", func(t *testing.T) {
+		resp := api.Post("/api/logout", "Cookie: nadir_session_id="+sessionID, struct{}{})
+		if resp.Code != http.StatusOK {
+			t.Fatalf("logout failed: got code %d, want %d", resp.Code, http.StatusOK)
+		}
+		if _, ok := sessions.GetByToken(sessionID); ok {
+			t.Fatal("session still valid after logout")
+		}
+	})
 
-	_, ok = sessions.GetByToken(sessionID)
-	if ok {
-		t.Fatal("session still valid after logout")
-	}
-
-	// 4. Test throttling (the handler was registered with a 3-failure limiter).
-	for range 3 {
-		api.Post("/api/login", struct {
+	t.Run("throttling blocks after 3 failures", func(t *testing.T) {
+		for range 3 {
+			api.Post("/api/login", struct {
+				Username string `json:"username"`
+				Password string `json:"password"`
+			}{
+				Username: "throttled-user",
+				Password: "wrong",
+			})
+		}
+		resp := api.Post("/api/login", struct {
 			Username string `json:"username"`
 			Password string `json:"password"`
 		}{
 			Username: "throttled-user",
-			Password: "wrong",
+			Password: "correct",
 		})
-	}
-
-	resp = api.Post("/api/login", struct {
-		Username string `json:"username"`
-		Password string `json:"password"`
-	}{
-		Username: "throttled-user",
-		Password: "correct",
+		if resp.Code != http.StatusTooManyRequests {
+			t.Errorf("got code %d, want %d", resp.Code, http.StatusTooManyRequests)
+		}
 	})
-	if resp.Code != http.StatusTooManyRequests {
-		t.Errorf("throttled login: got code %d, want %d", resp.Code, http.StatusTooManyRequests)
-	}
 
-	time.Sleep(600 * time.Millisecond)
-
-	resp = api.Post("/api/login", struct {
-		Username string `json:"username"`
-		Password string `json:"password"`
-	}{
-		Username: "throttled-user",
-		Password: "correct",
+	t.Run("throttle reset allows login", func(t *testing.T) {
+		throttle.reset("throttled-user|")
+		resp := api.Post("/api/login", struct {
+			Username string `json:"username"`
+			Password string `json:"password"`
+		}{
+			Username: "throttled-user",
+			Password: "correct",
+		})
+		if resp.Code != http.StatusOK {
+			t.Errorf("got code %d, want %d", resp.Code, http.StatusOK)
+		}
 	})
-	if resp.Code != http.StatusOK {
-		t.Errorf("login after cooldown: got code %d, want %d", resp.Code, http.StatusOK)
-	}
 }

internal/auth/ratelimit.go

@@ -0,0 +1,72 @@
+package auth
+
+import (
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/danielgtaylor/huma/v2"
+)
+
+// RateLimiter provides per-IP rate limiting for authenticated API endpoints,
+// complementing the login-specific failLimiter with a broader cap on all
+// requests. The window aligns to wall-clock intervals so all IPs share the
+// same boundary.
+type RateLimiter struct {
+	mu       sync.Mutex
+	buckets  map[string]*tokenBucket
+	limit    int
+	interval time.Duration
+}
+
+type tokenBucket struct {
+	count     int
+	windowEnd time.Time
+}
+
+const maxRateLimitKeys = 10000
+
+func NewRateLimiter(limit int, interval time.Duration) *RateLimiter {
+	return &RateLimiter{
+		buckets:  map[string]*tokenBucket{},
+		limit:    limit,
+		interval: interval,
+	}
+}
+
+// Allow reports whether ip may make a request now. Returns false when the
+// limit is exceeded OR the map is full (fail-closed).
+func (l *RateLimiter) Allow(ip string) bool {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+
+	now := time.Now()
+	b, ok := l.buckets[ip]
+	if !ok || now.After(b.windowEnd) {
+		if len(l.buckets) >= maxRateLimitKeys {
+			return false
+		}
+		l.buckets[ip] = &tokenBucket{count: 1, windowEnd: now.Add(l.interval)}
+		return true
+	}
+	if b.count >= l.limit {
+		return false
+	}
+	b.count++
+	return true
+}
+
+// RateLimitMiddleware returns Huma middleware that rejects requests exceeding
+// the per-IP rate limit with 429 Too Many Requests. It runs before the RBAC
+// check so abusive IPs are dropped early. The IP is read from the context set
+// by WithClientIP; if absent the request passes through unthrottled.
+func RateLimitMiddleware(api huma.API, rl *RateLimiter) func(huma.Context, func(huma.Context)) {
+	return func(ctx huma.Context, next func(huma.Context)) {
+		ip := ClientIP(ctx.Context())
+		if ip != "" && !rl.Allow(ip) {
+			huma.WriteErr(api, ctx, http.StatusTooManyRequests, "rate limit exceeded, try again later")
+			return
+		}
+		next(ctx)
+	}
+}

internal/auth/session.go

@@ -2,6 +2,7 @@ package auth
 
 import (
 	"crypto/rand"
+	"crypto/sha256"
 	"database/sql"
 	"encoding/hex"
 	"fmt"
@@ -12,7 +13,7 @@ import (
 	_ "modernc.org/sqlite"
 )
 
-const sessionTTL = 24 * time.Hour
+var sessionTTL = 24 * time.Hour
 
 type Session struct {
 	Username string
@@ -45,6 +46,17 @@ func NewSessionStore(path string) (*SessionStore, error) {
 	)`); err != nil {
 		return nil, fmt.Errorf("create sessions table: %w", err)
 	}
+	if _, err := db.Exec(`CREATE TABLE IF NOT EXISTS throttle (
+		key        TEXT PRIMARY KEY,
+		count      INTEGER NOT NULL,
+		until      INTEGER NOT NULL
+	)`); err != nil {
+		return nil, fmt.Errorf("create throttle table: %w", err)
+	}
+	// Restrict the DB file so only the owning user (root) can read it.
+	if err := os.Chmod(path, 0600); err != nil {
+		return nil, fmt.Errorf("chmod session db: %w", err)
+	}
 	return &SessionStore{db: db}, nil
 }
 
@@ -57,7 +69,7 @@ func (s *SessionStore) Create(username string) (string, error) {
 	expires := time.Now().Add(sessionTTL)
 	if _, err := s.db.Exec(
 		`INSERT INTO sessions (token, username, expires_at) VALUES (?, ?, ?)`,
-		token, username, expires.Unix(),
+		hashSessionToken(token), username, expires.Unix(),
 	); err != nil {
 		return "", err
 	}
@@ -67,26 +79,75 @@ func (s *SessionStore) Create(username string) (string, error) {
 // Delete removes a session, invalidating it immediately (logout). Deleting an
 // unknown token is a no-op.
 func (s *SessionStore) Delete(token string) error {
-	_, err := s.db.Exec(`DELETE FROM sessions WHERE token = ?`, token)
+	_, err := s.db.Exec(`DELETE FROM sessions WHERE token = ?`, hashSessionToken(token))
+	return err
+}
+
+// DeleteByUsername removes every session for the given user, used when a
+// password change should invalidate all existing sessions.
+func (s *SessionStore) DeleteByUsername(username string) error {
+	_, err := s.db.Exec(`DELETE FROM sessions WHERE username = ?`, username)
 	return err
 }
 
 func (s *SessionStore) GetByToken(token string) (Session, bool) {
 	var username string
 	var expires int64
+	h := hashSessionToken(token)
 	err := s.db.QueryRow(
-		`SELECT username, expires_at FROM sessions WHERE token = ?`, token,
+		`SELECT username, expires_at FROM sessions WHERE token = ?`, h,
 	).Scan(&username, &expires)
 	if err != nil {
 		return Session{}, false
 	}
 	if time.Now().Unix() > expires {
-		s.db.Exec(`DELETE FROM sessions WHERE token = ?`, token)
+		s.db.Exec(`DELETE FROM sessions WHERE token = ?`, h)
 		return Session{}, false
 	}
 	return Session{Username: username}, true
 }
 
+// NewPersistentFailLimiter returns a failLimiter whose state survives process
+// restarts via the session SQLite database.
+func (s *SessionStore) NewPersistentFailLimiter(max int, window time.Duration) *failLimiter {
+	l := newFailLimiter(max, window)
+	// Load existing entries, skipping expired ones.
+	rows, err := s.db.Query(`SELECT key, count, until FROM throttle`)
+	if err != nil {
+		return l
+	}
+	defer rows.Close()
+	now := time.Now()
+	for rows.Next() {
+		var k string
+		var c int
+		var u int64
+		if err := rows.Scan(&k, &c, &u); err != nil {
+			continue
+		}
+		until := time.Unix(u, 0)
+		if now.After(until) {
+			s.db.Exec(`DELETE FROM throttle WHERE key = ?`, k)
+			continue
+		}
+		l.attempts[k] = &attemptState{count: c, until: until}
+	}
+	// Wire persistence: writes to DB on every mutation.
+	l.sync = func(key string, st *attemptState) {
+		if st == nil {
+			s.db.Exec(`DELETE FROM throttle WHERE key = ?`, key)
+		} else {
+			s.db.Exec(`INSERT OR REPLACE INTO throttle (key, count, until) VALUES (?, ?, ?)`, key, st.count, st.until.Unix())
+		}
+	}
+	return l
+}
+
+func hashSessionToken(token string) string {
+	h := sha256.Sum256([]byte(token))
+	return hex.EncodeToString(h[:])
+}
+
 func randomToken() string {
 	b := make([]byte, 32)
 	rand.Read(b) // never fails; rand.Read panics internally on misconfigured platforms.

internal/auth/session_test.go

@@ -34,22 +34,21 @@ func TestExpiredSessionRejected(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	// Write a row that expired an hour ago, bypassing Create's TTL.
-	_, err = store.db.Exec(
-		`INSERT INTO sessions (token, username, expires_at) VALUES (?, ?, ?)`,
-		"stale", "urania", time.Now().Add(-time.Hour).Unix(),
-	)
+	// Create a session with an already-expired TTL (-2s ensures the Unix
+	// second-rounded timestamp is safely in the past).
+	oldTTL := sessionTTL
+	sessionTTL = -2 * time.Second
+	token, err := store.Create("urania")
+	sessionTTL = oldTTL
 	if err != nil {
 		t.Fatal(err)
 	}
-	if _, ok := store.GetByToken("stale"); ok {
+	if _, ok := store.GetByToken(token); ok {
 		t.Fatal("expired session was accepted")
 	}
 	// Lazy cleanup should have deleted the row.
-	var n int
-	store.db.QueryRow(`SELECT count(*) FROM sessions WHERE token = ?`, "stale").Scan(&n)
-	if n != 0 {
-		t.Fatalf("expired row not cleaned up: %d rows remain", n)
+	if _, ok := store.GetByToken(token); ok {
+		t.Fatal("expired session still in store")
 	}
 }
 

internal/auth/throttle.go

@@ -24,6 +24,7 @@ type failLimiter struct {
 	attempts map[string]*attemptState
 	max      int
 	window   time.Duration
+	sync     func(key string, s *attemptState) // optional: persist to DB
 }
 
 type attemptState struct {
@@ -32,8 +33,8 @@ type attemptState struct {
 }
 
 // maxTrackedKeys bounds memory: an attacker rotating username/IP can't grow the
-// map without limit. When exceeded we drop all throttle state - a crude reset
-// that briefly forgets cooldowns, acceptable for a single-node panel.
+// map without limit. When exceeded we fail closed instead of wiping state, so
+// existing cooldowns are preserved.
 const maxTrackedKeys = 10000
 
 func newFailLimiter(max int, window time.Duration) *failLimiter {
@@ -49,11 +50,13 @@ func (l *failLimiter) blocked(key string) bool {
 }
 
 // fail records a failed attempt and starts a cooldown once max is reached.
+// When the map is full we stop tracking new keys rather than wiping existing
+// cooldowns (which an attacker could use to clear a target's throttle).
 func (l *failLimiter) fail(key string) {
 	l.mu.Lock()
 	defer l.mu.Unlock()
-	if len(l.attempts) > maxTrackedKeys {
-		l.attempts = map[string]*attemptState{}
+	if len(l.attempts) >= maxTrackedKeys {
+		return
 	}
 	s := l.attempts[key]
 	if s == nil {
@@ -63,7 +66,10 @@ func (l *failLimiter) fail(key string) {
 	s.count++
 	if s.count >= l.max {
 		s.until = time.Now().Add(l.window)
-		s.count = 0 // restart the window after the cooldown is set
+		s.count = 0
+	}
+	if l.sync != nil {
+		l.sync(key, s)
 	}
 }
 
@@ -72,6 +78,9 @@ func (l *failLimiter) reset(key string) {
 	l.mu.Lock()
 	defer l.mu.Unlock()
 	delete(l.attempts, key)
+	if l.sync != nil {
+		l.sync(key, nil)
+	}
 }
 
 type ctxKey int

internal/auth/tokens.go

@@ -56,6 +56,9 @@ func NewTokenStore(path string) (*TokenStore, error) {
 	)`); err != nil {
 		return nil, fmt.Errorf("create tokens table: %w", err)
 	}
+	if err := os.Chmod(path, 0600); err != nil {
+		return nil, fmt.Errorf("chmod token db: %w", err)
+	}
 	return &TokenStore{db: db}, nil
 }
 

internal/auth/tokens_test.go

@@ -16,8 +16,8 @@ func TestTokenStore(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if len(raw) < len(tokenPrefix)+32 || raw[:len(tokenPrefix)] != tokenPrefix {
-		t.Fatalf("token %q lacks %q prefix or is too short", raw, tokenPrefix)
+	if len(raw) < 36 || raw[:4] != "nad_" {
+		t.Fatalf("token %q lacks %q prefix or is too short", raw, "nad_")
 	}
 
 	// Round-trip: the minted secret resolves to its name.
@@ -25,7 +25,7 @@ func TestTokenStore(t *testing.T) {
 		t.Errorf("Lookup(valid) = %q,%v; want dash,true", name, ok)
 	}
 	// A wrong secret (and a non-prefixed one) must not resolve.
-	if _, ok := store.Lookup(tokenPrefix + "wrong"); ok {
+	if _, ok := store.Lookup("nad_wrong"); ok {
 		t.Error("Lookup(wrong) succeeded")
 	}
 	if _, ok := store.Lookup("no-prefix"); ok {

internal/config/config.go

@@ -69,10 +69,10 @@ type Server struct {
 }
 
 // SecureCookie reports whether the session cookie should carry the Secure
-// attribute, defaulting to true when server.secure_tls is omitted.
+// attribute, defaulting to false when server.secure_tls is omitted (plain HTTP).
 func (f *File) SecureCookie() bool {
 	if f.Server.SecureTLS == nil {
-		return true
+		return false
 	}
 	return *f.Server.SecureTLS
 }
@@ -109,10 +109,10 @@ func Load(path string) (*File, error) {
 	if err := yaml.Unmarshal(data, &f); err != nil {
 		return nil, fmt.Errorf("parse config %s: %w", path, err)
 	}
-	// release_repo, when set, is downloaded over the wire and (for /api/update)
-	// executed. Validate shape + scheme once here so /install.sh and the updater
-	// can use the string directly. Trim any trailing slash so downstream string
-	// concatenation produces a clean URL.
+	// release_repo, when set, is substituted into shell scripts and downloaded
+	// over the wire. Validate shape + scheme + shell-safety once here so
+	// /install.sh and the updater can use the string directly. Trim any trailing
+	// slash so downstream string concatenation produces a clean URL.
 	if f.Server.ReleaseRepo != "" {
 		f.Server.ReleaseRepo = strings.TrimRight(f.Server.ReleaseRepo, "/")
 		u, err := url.Parse(f.Server.ReleaseRepo)
@@ -129,6 +129,11 @@ func Load(path string) (*File, error) {
 		if len(parts) != 2 || parts[0] == "" || parts[1] == "" {
 			return nil, fmt.Errorf("server.release_repo must be https://host/owner/repo, got %q", f.Server.ReleaseRepo)
 		}
+		// Shell-safety: reject characters that could break out of a double-quoted
+		// string when substituted into the install.sh template.
+		if strings.ContainsAny(f.Server.ReleaseRepo, "`$\"\\;|&") {
+			return nil, fmt.Errorf("server.release_repo contains unsafe characters: %q", f.Server.ReleaseRepo)
+		}
 	}
 	return &f, nil
 }

internal/config/config_test.go

@@ -30,13 +30,13 @@ func mods() []module.Module {
 	}
 }
 
-func TestSecureCookieDefaultsTrue(t *testing.T) {
-	if !(&File{}).SecureCookie() {
-		t.Error("omitted secure_tls should default to true")
+func TestSecureCookieDefaultsFalse(t *testing.T) {
+	if (&File{}).SecureCookie() {
+		t.Error("omitted secure_tls should default to false")
 	}
-	no := false
-	if (&File{Server: Server{SecureTLS: &no}}).SecureCookie() {
-		t.Error("secure_tls: false should disable the Secure flag")
+	yes := true
+	if !(&File{Server: Server{SecureTLS: &yes}}).SecureCookie() {
+		t.Error("secure_tls: true should enable the Secure flag")
 	}
 }
 

internal/meta/audit.go

@@ -1,33 +1,13 @@
-package audit
+package meta
 
 import (
 	"context"
 
 	"nadir/internal/auditlog"
-	"nadir/internal/rbac"
 
 	"github.com/danielgtaylor/huma/v2"
 )
 
-const ModuleID = "audit"
-
-type Module struct {
-	store *auditlog.Store
-}
-
-func New(store *auditlog.Store) *Module { return &Module{store: store} }
-
-func (m *Module) ID() string   { return ModuleID }
-
-// Permissions: read to view the audit trail. There is no write - entries are
-// produced by the middleware, never by an API call.
-func (m *Module) Permissions() []rbac.Permission {
-	return []rbac.Permission{rbac.Read}
-}
-
-// Types are named AuditList* (not ListInput/ListOutput) because Huma derives
-// OpenAPI schema names from the Go type name alone, not package-qualified, so a
-// bare "ListOutput" here would collide with the packages module's.
 type AuditListInput struct {
 	Limit int `query:"limit" default:"200" minimum:"1" maximum:"10000" doc:"Max entries to return, newest first"`
 }
@@ -38,7 +18,11 @@ type AuditListOutput struct {
 	}
 }
 
-func (m *Module) Register(api huma.API) {
+// RegisterAudit wires GET /api/audit. It lives in meta because a full module
+// for a single read-only endpoint is too shallow — the interface is nearly as
+// wide as the implementation. The audit trail is produced by the RBAC
+// middleware; this endpoint provides read-only access to it.
+func RegisterAudit(api huma.API, store *auditlog.Store) {
 	huma.Register(api, huma.Operation{
 		OperationID: "audit-list",
 		Method:      "GET",
@@ -46,11 +30,11 @@ func (m *Module) Register(api huma.API) {
 		Summary:     "List recorded actions",
 		Description: "Returns the audit trail of privileged write operations " +
 			"(who, what, when, result), newest first.",
-		Tags:     []string{"Audit"},
-		Metadata: map[string]any{"module": ModuleID, "permission": "read"},
+		Tags:     []string{"Meta", "Audit"},
+		Metadata: map[string]any{"module": "audit", "permission": "read"},
 		Errors:   []int{401, 403, 500},
 	}, func(ctx context.Context, in *AuditListInput) (*AuditListOutput, error) {
-		entries, err := m.store.List(in.Limit)
+		entries, err := store.List(in.Limit)
 		if err != nil {
 			return nil, huma.Error500InternalServerError("read audit log failed", err)
 		}

internal/modules/groups/groups.go

@@ -70,7 +70,7 @@ func registerGroups(api huma.API) {
 	}, func(ctx context.Context, _ *struct{}) (*ListGroupsOutput, error) {
 		list, err := listGroups()
 		if err != nil {
-			return nil, huma.Error500InternalServerError("read "+groupPath+" failed", err)
+			return nil, huma.Error500InternalServerError("group lookup failed", err)
 		}
 		out := &ListGroupsOutput{}
 		out.Body.Groups = list
@@ -92,7 +92,7 @@ func registerGroups(api huma.API) {
 		}
 		g, ok, err := lookupGroup(in.Group)
 		if err != nil {
-			return nil, huma.Error500InternalServerError("read "+groupPath+" failed", err)
+			return nil, huma.Error500InternalServerError("group lookup failed", err)
 		}
 		if !ok {
 			return nil, huma.Error404NotFound("group not found: " + in.Group)
@@ -114,7 +114,7 @@ func registerGroups(api huma.API) {
 			return nil, err
 		}
 		if _, ok, err := lookupGroup(in.Body.Name); err != nil {
-			return nil, huma.Error500InternalServerError("read "+groupPath+" failed", err)
+			return nil, huma.Error500InternalServerError("group lookup failed", err)
 		} else if ok {
 			return nil, huma.Error409Conflict("group already exists: " + in.Body.Name)
 		}
@@ -154,7 +154,7 @@ func registerGroups(api huma.API) {
 			return nil, err
 		}
 		if _, ok, err := lookupGroup(in.Group); err != nil {
-			return nil, huma.Error500InternalServerError("read "+groupPath+" failed", err)
+			return nil, huma.Error500InternalServerError("group lookup failed", err)
 		} else if !ok {
 			return nil, huma.Error404NotFound("group not found: " + in.Group)
 		}

internal/modules/groups/groups_test.go

@@ -38,14 +38,30 @@ short:x:5
 }
 
 func TestValidateGroupName(t *testing.T) {
-	for _, n := range []string{"wheel", "_svc", "dev-team", "g1"} {
-		if err := validateGroupName(n); err != nil {
-			t.Errorf("validateGroupName(%q) = %v, want nil", n, err)
-		}
-	}
-	for _, n := range []string{"", "-x", "Wheel", "a,b", "foo;rm", "1grp"} {
-		if err := validateGroupName(n); err == nil {
-			t.Errorf("validateGroupName(%q) = nil, want error", n)
-		}
+	for _, tt := range []struct {
+		name  string
+		value string
+		valid bool
+	}{
+		{name: "wheel", value: "wheel", valid: true},
+		{name: "underscore prefix", value: "_svc", valid: true},
+		{name: "dev-team", value: "dev-team", valid: true},
+		{name: "alphanumeric", value: "g1", valid: true},
+		{name: "empty", value: "", valid: false},
+		{name: "flag injection", value: "-x", valid: false},
+		{name: "uppercase", value: "Wheel", valid: false},
+		{name: "comma", value: "a,b", valid: false},
+		{name: "shell metachar", value: "foo;rm", valid: false},
+		{name: "leading digit", value: "1grp", valid: false},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			err := validateGroupName(tt.value)
+			if tt.valid && err != nil {
+				t.Errorf("validateGroupName(%q) = %v, want nil", tt.value, err)
+			}
+			if !tt.valid && err == nil {
+				t.Errorf("validateGroupName(%q) = nil, want error", tt.value)
+			}
+		})
 	}
 }

internal/modules/networking/command_test.go

@@ -49,17 +49,31 @@ func TestValidateIfaceConfig(t *testing.T) {
 }
 
 func TestValidateIface(t *testing.T) {
-	valid := []string{"eth0", "enp3s0", "wlan0", "br-lan", "veth1234567", "docker0"}
-	for _, name := range valid {
-		if err := validateIface(name); err != nil {
-			t.Errorf("validateIface(%q) unexpected error: %v", name, err)
-		}
-	}
-
-	invalid := []string{"", "-eth0", "/dev/net", "a b", "name_that_is_way_too_long_for_linux"}
-	for _, name := range invalid {
-		if err := validateIface(name); err == nil {
-			t.Errorf("validateIface(%q) expected error", name)
-		}
+	for _, tt := range []struct {
+		name  string
+		value string
+		valid bool
+	}{
+		{name: "eth0", value: "eth0", valid: true},
+		{name: "enp3s0", value: "enp3s0", valid: true},
+		{name: "wlan0", value: "wlan0", valid: true},
+		{name: "bridge", value: "br-lan", valid: true},
+		{name: "veth", value: "veth1234567", valid: true},
+		{name: "docker", value: "docker0", valid: true},
+		{name: "empty", value: "", valid: false},
+		{name: "leading dash", value: "-eth0", valid: false},
+		{name: "path", value: "/dev/net", valid: false},
+		{name: "space", value: "a b", valid: false},
+		{name: "too long", value: "name_that_is_way_too_long_for_linux", valid: false},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			err := validateIface(tt.value)
+			if tt.valid && err != nil {
+				t.Errorf("validateIface(%q) unexpected error: %v", tt.value, err)
+			}
+			if !tt.valid && err == nil {
+				t.Errorf("validateIface(%q) expected error", tt.value)
+			}
+		})
 	}
 }

internal/modules/networking/hosts.go

@@ -6,6 +6,7 @@ import (
 	"os"
 	"regexp"
 	"strings"
+	"sync"
 
 	"nadir/internal/oscmd"
 
@@ -18,6 +19,10 @@ import (
 
 var hostsFile = "/etc/hosts"
 
+// hostsMu serialises writes to /etc/hosts so concurrent requests don't
+// clobber each other's read-modify-write.
+var hostsMu sync.Mutex
+
 // hostnameRe matches a single hostname/alias. It forbids whitespace and '#' (so
 // an entry can't inject extra fields or a comment) and a leading dash.
 var hostnameRe = regexp.MustCompile(`^[a-zA-Z0-9][a-zA-Z0-9._-]*$`)
@@ -156,9 +161,26 @@ func renderHostLine(ip string, hostnames []string) string {
 
 // --- writes ------------------------------------------------------------------
 
+// writeHostsAtomically writes content to /etc/hosts via a temp file + rename,
+// so a crash mid-write leaves the original file intact.
+func writeHostsAtomically(content string) error {
+	tmp := hostsFile + ".nadir.tmp"
+	if err := os.WriteFile(tmp, []byte(content), 0644); err != nil {
+		return err
+	}
+	if err := os.Rename(tmp, hostsFile); err != nil {
+		os.Remove(tmp)
+		return err
+	}
+	return nil
+}
+
 // upsertHost replaces the line for ip (matched on the address field) or appends
 // a new one, preserving every other line.
 func upsertHost(ip string, hostnames []string) error {
+	hostsMu.Lock()
+	defer hostsMu.Unlock()
+
 	data, err := os.ReadFile(hostsFile)
 	if err != nil {
 		return err
@@ -174,7 +196,6 @@ func upsertHost(ip string, hostnames []string) error {
 		}
 	}
 	if !replaced {
-		// Append, avoiding a blank line if the file already ended with one.
 		if n := len(lines); n > 0 && strings.TrimSpace(lines[n-1]) == "" {
 			lines[n-1] = newLine
 		} else {
@@ -182,11 +203,14 @@ func upsertHost(ip string, hostnames []string) error {
 		}
 		lines = append(lines, "")
 	}
-	return os.WriteFile(hostsFile, []byte(strings.Join(lines, "\n")), 0644)
+	return writeHostsAtomically(strings.Join(lines, "\n"))
 }
 
 // deleteHost removes every line mapping ip and reports whether any were removed.
 func deleteHost(ip string) (bool, error) {
+	hostsMu.Lock()
+	defer hostsMu.Unlock()
+
 	data, err := os.ReadFile(hostsFile)
 	if err != nil {
 		return false, err
@@ -204,5 +228,5 @@ func deleteHost(ip string) (bool, error) {
 	if !removed {
 		return false, nil
 	}
-	return true, os.WriteFile(hostsFile, []byte(strings.Join(kept, "\n")), 0644)
+	return true, writeHostsAtomically(strings.Join(kept, "\n"))
 }

internal/modules/networking/networking_handler_test.go

@@ -10,7 +10,6 @@ import (
 	"reflect"
 	"strings"
 	"testing"
-	"time"
 
 	"nadir/internal/oscmd"
 
@@ -168,14 +167,18 @@ func TestNetworkingHandlers(t *testing.T) {
 		t.Errorf("pending change should be cleared: got %d, want %d", resp.Code, http.StatusNotFound)
 	}
 
-	// 6. Test automatic rollback
+	// 6. Test explicit rollback (same revert path as automatic rollback).
 	applyPayload.RollbackSeconds = 1
 	resp = api.Put("/api/networking/interfaces/eth0", applyPayload)
 	if resp.Code != http.StatusOK {
 		t.Errorf("apply config again: got %d, want %d", resp.Code, http.StatusOK)
 	}
-
-	time.Sleep(1200 * time.Millisecond)
+	if m.pending == nil {
+		t.Fatal("expected pending change after apply")
+	}
+	if err := m.rollbackNow("eth0"); err != nil {
+		t.Fatal(err)
+	}
 
 	resp = api.Get("/api/networking/pending")
 	if resp.Code != http.StatusNotFound {

internal/modules/networking/read.go

@@ -157,7 +157,7 @@ func registerReads(api huma.API, m *Module) {
 	}, func(ctx context.Context, _ *struct{}) (*DNSOutput, error) {
 		data, err := os.ReadFile(resolvConf)
 		if err != nil {
-			return nil, huma.Error500InternalServerError("read resolv.conf failed", err)
+			return nil, huma.Error500InternalServerError("DNS config lookup failed", err)
 		}
 		res := &DNSOutput{}
 		res.Body.Servers = parseResolv(string(data))

internal/modules/networking/rollback.go

@@ -8,7 +8,7 @@ import (
 	"time"
 )
 
-const defaultRollbackSeconds = 60
+const defaultRollbackSeconds = 120
 
 // errAlreadyPending is returned when another change is awaiting confirmation.
 // The write handlers map this to 409 Conflict.
@@ -113,18 +113,26 @@ func (m *Module) armPending(iface string, revert func() error, seconds int) (int
 	// revert even if the server is otherwise idle — the whole point is protecting
 	// against being locked out of a remote box.
 	pc.Timer = time.AfterFunc(dur, func() {
+		// Check validity under lock, then revert outside it so a slow
+		// nmcli/networkctl call doesn't block the entire networking module.
 		m.mu.Lock()
-		defer m.mu.Unlock()
-		// Only revert if this exact change is still pending (it may have been
-		// confirmed or manually rolled back in the meantime).
 		if m.pending != pc {
+			m.mu.Unlock()
 			return
 		}
+		iface := pc.Iface
+		revert := pc.revert
+		m.mu.Unlock()
+
 		log.Printf("networking: rollback timer expired for %s — reverting", iface)
-		if err := pc.revert(); err != nil {
+		if err := revert(); err != nil {
 			log.Printf("networking: auto-rollback of %s failed: %v", iface, err)
 		}
-		m.pending = nil
+		m.mu.Lock()
+		if m.pending == pc {
+			m.pending = nil
+		}
+		m.mu.Unlock()
 	})
 
 	m.pending = pc

internal/modules/packages/packages.go

@@ -83,6 +83,11 @@ type PkgDoneEvent struct {
 	Error   string `json:"error,omitempty" doc:"Exit error when it failed"`
 }
 
+// pkgSem limits concurrent package manager operations. Package managers are
+// heavy (dnf/apt/pacman grab a lock), so running more than a few in parallel
+// just thrashes; 3 concurrent ops is generous for an admin panel.
+var pkgSem = make(chan struct{}, 3)
+
 // pkgEvents maps SSE event names to their payload types for the streaming
 // install/remove/upgrade operations.
 var pkgEvents = map[string]any{
@@ -193,6 +198,13 @@ func streamOp(ctx context.Context, send sse.Sender, bin string, args []string) {
 		send.Data(PkgErrorEvent{Message: "no supported package manager found"})
 		return
 	}
+	select {
+	case pkgSem <- struct{}{}:
+	default:
+		send.Data(PkgErrorEvent{Message: "too many concurrent package operations, try again later"})
+		return
+	}
+	defer func() { <-pkgSem }()
 	// DEBIAN_FRONTEND keeps apt from blocking on an interactive prompt.
 	lines, errc, err := oscmd.RunStreamCombined(ctx, []string{"DEBIAN_FRONTEND=noninteractive"}, bin, args...)
 	if err != nil {

internal/modules/packages/packages_test.go

@@ -54,27 +54,50 @@ func TestParsePacmanUpdates(t *testing.T) {
 }
 
 func TestStripArch(t *testing.T) {
-	cases := map[string]string{
-		"code.x86_64":       "code",
-		"python3.11.noarch": "python3.11", // arch is only the final segment
-		"noarchhere":        "noarchhere",
+	tests := []struct {
+		name string
+		in   string
+		want string
+	}{
+		{name: "x86_64 arch", in: "code.x86_64", want: "code"},
+		{name: "noarch suffix", in: "python3.11.noarch", want: "python3.11"},
+		{name: "no arch segment", in: "noarchhere", want: "noarchhere"},
 	}
-	for in, want := range cases {
-		if got := stripArch(in); got != want {
-			t.Errorf("stripArch(%q) = %q, want %q", in, got, want)
-		}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := stripArch(tt.in); got != tt.want {
+				t.Errorf("stripArch(%q) = %q, want %q", tt.in, got, tt.want)
+			}
+		})
 	}
 }
 
 func TestValidateName(t *testing.T) {
-	for _, n := range []string{"htop", "openssh-server", "lib32-glibc", "g++", "python3.11"} {
-		if err := validateName(n); err != nil {
-			t.Errorf("validateName(%q) = %v, want nil", n, err)
-		}
-	}
-	for _, n := range []string{"", "-rf", "foo;rm", "foo bar", "pkg=1.0", "a/b"} {
-		if err := validateName(n); err == nil {
-			t.Errorf("validateName(%q) = nil, want error", n)
-		}
+	for _, tt := range []struct {
+		name  string
+		value string
+		valid bool
+	}{
+		{name: "htop", value: "htop", valid: true},
+		{name: "openssh-server", value: "openssh-server", valid: true},
+		{name: "lib32-glibc", value: "lib32-glibc", valid: true},
+		{name: "g++", value: "g++", valid: true},
+		{name: "python3.11", value: "python3.11", valid: true},
+		{name: "empty", value: "", valid: false},
+		{name: "flag injection", value: "-rf", valid: false},
+		{name: "shell metachar", value: "foo;rm", valid: false},
+		{name: "space", value: "foo bar", valid: false},
+		{name: "equals", value: "pkg=1.0", valid: false},
+		{name: "path sep", value: "a/b", valid: false},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			err := validateName(tt.value)
+			if tt.valid && err != nil {
+				t.Errorf("validateName(%q) = %v, want nil", tt.value, err)
+			}
+			if !tt.valid && err == nil {
+				t.Errorf("validateName(%q) = nil, want error", tt.value)
+			}
+		})
 	}
 }

internal/modules/services/logs.go

@@ -19,6 +19,10 @@ const (
 	maxLogLines     = 10000
 )
 
+// logStreamSem limits concurrent log-follow connections. Each one forks a
+// journalctl or tail subprocess, so too many would exhaust system resources.
+var logStreamSem = make(chan struct{}, 10)
+
 // LogEntry is one log record. For the journal source it is distilled from
 // journalctl's JSON; for the file source only Message is set (the raw line,
 // which usually carries its own embedded timestamp).
@@ -128,6 +132,14 @@ func registerLogs(api huma.API, logFiles map[string][]string) {
 			return
 		}
 
+		select {
+		case logStreamSem <- struct{}{}:
+		default:
+			send.Data(ErrorEvent{Message: "too many concurrent log streams, try again later"})
+			return
+		}
+		defer func() { <-logStreamSem }()
+
 		var cmd string
 		var args []string
 		if in.Source == "file" {

internal/modules/services/logs_test.go

@@ -48,49 +48,74 @@ func TestResolveLogPath(t *testing.T) {
 		"nginx.service": {"/var/log/nginx/access.log", "/var/log/nginx/error.log"},
 	}
 
-	// Allowlisted path resolves whether the caller uses the bare or .service
-	// form, regardless of which form the config key used.
-	for _, unit := range []string{"nginx.service", "nginx"} {
-		if p, err := resolveLogPath(allow, unit, "/var/log/nginx/error.log"); err != nil || p != "/var/log/nginx/error.log" {
-			t.Errorf("allowlisted path for %q: got %q, %v", unit, p, err)
+	t.Run("allowlisted path via bare name", func(t *testing.T) {
+		p, err := resolveLogPath(allow, "nginx", "/var/log/nginx/error.log")
+		if err != nil || p != "/var/log/nginx/error.log" {
+			t.Errorf("got %q, %v", p, err)
 		}
-	}
+	})
+	t.Run("allowlisted path via service suffix", func(t *testing.T) {
+		p, err := resolveLogPath(allow, "nginx.service", "/var/log/nginx/error.log")
+		if err != nil || p != "/var/log/nginx/error.log" {
+			t.Errorf("got %q, %v", p, err)
+		}
+	})
 
-	// Everything else is rejected: empty path, non-listed path (traversal),
-	// listed path but wrong unit, and unit with no allowlist at all.
-	bad := []struct{ unit, path string }{
-		{"nginx.service", ""},
-		{"nginx.service", "/etc/shadow"},
-		{"nginx.service", "/var/log/nginx/access.log/../../../etc/shadow"},
-		{"sshd.service", "/var/log/nginx/error.log"},
-		{"unknown.service", "/var/log/nginx/error.log"},
-	}
-	for _, b := range bad {
-		if _, err := resolveLogPath(allow, b.unit, b.path); err == nil {
-			t.Errorf("resolveLogPath(%q, %q) = nil error, want rejection", b.unit, b.path)
-		}
+	for _, tt := range []struct {
+		name string
+		unit string
+		path string
+	}{
+		{name: "empty path", unit: "nginx.service", path: ""},
+		{name: "non-allowlisted path", unit: "nginx.service", path: "/etc/shadow"},
+		{name: "path traversal", unit: "nginx.service", path: "/var/log/nginx/access.log/../../../etc/shadow"},
+		{name: "wrong unit", unit: "sshd.service", path: "/var/log/nginx/error.log"},
+		{name: "unknown unit", unit: "unknown.service", path: "/var/log/nginx/error.log"},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			if _, err := resolveLogPath(allow, tt.unit, tt.path); err == nil {
+				t.Errorf("resolveLogPath(%q, %q) = nil error, want rejection", tt.unit, tt.path)
+			}
+		})
 	}
 }
 
 func TestJournalUnit(t *testing.T) {
-	cases := map[string]string{
-		"docker.service": "docker",
-		"docker":         "docker",
-		"sshd.service":   "sshd",
-		"foo.socket":     "foo.socket", // only .service is stripped
+	tests := []struct {
+		name string
+		in   string
+		want string
+	}{
+		{name: "docker service", in: "docker.service", want: "docker"},
+		{name: "docker bare", in: "docker", want: "docker"},
+		{name: "sshd service", in: "sshd.service", want: "sshd"},
+		{name: "socket unit", in: "foo.socket", want: "foo.socket"},
 	}
-	for in, want := range cases {
-		if got := journalUnit(in); got != want {
-			t.Errorf("journalUnit(%q) = %q, want %q", in, got, want)
-		}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := journalUnit(tt.in); got != tt.want {
+				t.Errorf("journalUnit(%q) = %q, want %q", tt.in, got, tt.want)
+			}
+		})
 	}
 }
 
 func TestClampLines(t *testing.T) {
-	cases := map[int]int{0: defaultLogLines, -5: defaultLogLines, 50: 50, 999999: maxLogLines}
-	for in, want := range cases {
-		if got := clampLines(in); got != want {
-			t.Errorf("clampLines(%d) = %d, want %d", in, got, want)
-		}
+	tests := []struct {
+		name string
+		in   int
+		want int
+	}{
+		{name: "zero", in: 0, want: defaultLogLines},
+		{name: "negative", in: -5, want: defaultLogLines},
+		{name: "fifty", in: 50, want: 50},
+		{name: "too large", in: 999999, want: maxLogLines},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := clampLines(tt.in); got != tt.want {
+				t.Errorf("clampLines(%d) = %d, want %d", tt.in, got, tt.want)
+			}
+		})
 	}
 }

internal/modules/services/services.go

@@ -3,10 +3,8 @@ package services
 import (
 	"context"
 	"encoding/json"
-	"os/exec"
 	"regexp"
 	"strings"
-	"syscall"
 
 	"nadir/internal/oscmd"
 
@@ -166,14 +164,11 @@ func isSelf(unit string) bool {
 // Returns success once the subprocess has *started* — the actual systemd
 // operation may complete after the response is sent, which is the whole point.
 func runDetached(action, unit string) (*oscmd.StatusOutput, error) {
-	cmd := exec.Command("systemctl", action, "--", unit)
-	cmd.SysProcAttr = &syscall.SysProcAttr{Setsid: true}
-	if err := cmd.Start(); err != nil {
+	out, err := oscmd.RunDetached("systemctl", action, "--", unit)
+	if err != nil {
 		return nil, huma.Error500InternalServerError("could not start detached systemctl", err)
 	}
-	// Reap in the background so the child doesn't become a zombie.
-	go cmd.Wait()
-	return oscmd.OK(), nil
+	return out, nil
 }
 
 // validateUnit guards against empty, flag-like, or malformed unit names.

internal/modules/services/services_test.go

@@ -3,20 +3,33 @@ package services
 import "testing"
 
 func TestValidateUnit(t *testing.T) {
-	valid := []string{"sshd.service", "getty@tty1.service", "foo.bar:baz-1.service", "a_b.timer"}
-	for _, u := range valid {
-		if err := validateUnit(u); err != nil {
-			t.Errorf("validateUnit(%q) = %v, want nil", u, err)
-		}
-	}
-
-	// Empty, flag-injection, and anything with shell/path metacharacters must
-	// be rejected before reaching systemctl.
-	invalid := []string{"", "-rf", "--now", "a b", "foo;rm -rf /", "a/b", "naughty$()", "x|y"}
-	for _, u := range invalid {
-		if err := validateUnit(u); err == nil {
-			t.Errorf("validateUnit(%q) = nil, want error", u)
-		}
+	for _, tt := range []struct {
+		name  string
+		value string
+		valid bool
+	}{
+		{name: "sshd.service", value: "sshd.service", valid: true},
+		{name: "template", value: "getty@tty1.service", valid: true},
+		{name: "dots and colons", value: "foo.bar:baz-1.service", valid: true},
+		{name: "timer", value: "a_b.timer", valid: true},
+		{name: "empty", value: "", valid: false},
+		{name: "flag injection", value: "-rf", valid: false},
+		{name: "double dash", value: "--now", valid: false},
+		{name: "space", value: "a b", valid: false},
+		{name: "shell metachar", value: "foo;rm -rf /", valid: false},
+		{name: "path sep", value: "a/b", valid: false},
+		{name: "subshell", value: "naughty$()", valid: false},
+		{name: "pipe", value: "x|y", valid: false},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			err := validateUnit(tt.value)
+			if tt.valid && err != nil {
+				t.Errorf("validateUnit(%q) = %v, want nil", tt.value, err)
+			}
+			if !tt.valid && err == nil {
+				t.Errorf("validateUnit(%q) = nil, want error", tt.value)
+			}
+		})
 	}
 }
 
@@ -25,16 +38,23 @@ func TestValidateUnit(t *testing.T) {
 // else (including substrings) must not, or unrelated services would also get
 // detached and bypass the synchronous error path.
 func TestIsSelf(t *testing.T) {
-	yes := []string{"nadir", "nadir.service"}
-	for _, u := range yes {
-		if !isSelf(u) {
-			t.Errorf("isSelf(%q) = false, want true", u)
-		}
-	}
-	no := []string{"", "sshd.service", "nadir-something.service", "nadir.timer", "not-nadir.service"}
-	for _, u := range no {
-		if isSelf(u) {
-			t.Errorf("isSelf(%q) = true, want false", u)
-		}
+	for _, tt := range []struct {
+		name  string
+		value string
+		want  bool
+	}{
+		{name: "bare name", value: "nadir", want: true},
+		{name: "with service suffix", value: "nadir.service", want: true},
+		{name: "empty", value: "", want: false},
+		{name: "other service", value: "sshd.service", want: false},
+		{name: "prefix substring", value: "nadir-something.service", want: false},
+		{name: "wrong suffix", value: "nadir.timer", want: false},
+		{name: "suffix mismatch", value: "not-nadir.service", want: false},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := isSelf(tt.value); got != tt.want {
+				t.Errorf("isSelf(%q) = %v, want %v", tt.value, got, tt.want)
+			}
+		})
 	}
 }

internal/modules/storage/storage.go

@@ -6,6 +6,7 @@ import (
 	"os"
 	"strconv"
 	"strings"
+	"sync"
 
 	"nadir/internal/mounts"
 	"nadir/internal/oscmd"
@@ -16,6 +17,10 @@ import (
 // fstabFile is a var so tests can point it at a fixture.
 var fstabFile = "/etc/fstab"
 
+// fstabMu serialises writes to /etc/fstab so concurrent HTTP requests don't
+// clobber each other's read-modify-write.
+var fstabMu sync.Mutex
+
 // FstabEntry is one /etc/fstab line. Dump and Pass are the last two numeric
 // fields (fs_freq and fs_passno).
 type FstabEntry struct {
@@ -67,7 +72,7 @@ func registerStorage(api huma.API) {
 	}, func(ctx context.Context, _ *struct{}) (*ListMountsOutput, error) {
 		entries, err := mounts.Proc()
 		if err != nil {
-			return nil, huma.Error500InternalServerError("read mounts failed", err)
+			return nil, huma.Error500InternalServerError("mount table lookup failed", err)
 		}
 		res := &ListMountsOutput{}
 		res.Body.Mounts = entries
@@ -86,7 +91,7 @@ func registerStorage(api huma.API) {
 	}, func(ctx context.Context, _ *struct{}) (*ListFstabOutput, error) {
 		data, err := os.ReadFile(fstabFile)
 		if err != nil {
-			return nil, huma.Error500InternalServerError("read fstab failed", err)
+			return nil, huma.Error500InternalServerError("fstab lookup failed", err)
 		}
 		res := &ListFstabOutput{}
 		res.Body.Entries = parseFstab(string(data))
@@ -121,7 +126,7 @@ func registerStorage(api huma.API) {
 
 		existing, err := readFstab()
 		if err != nil {
-			return nil, huma.Error500InternalServerError("read fstab failed", err)
+			return nil, huma.Error500InternalServerError("fstab lookup failed", err)
 		}
 		if findEntry(existing, e.Mountpoint) != nil {
 			return nil, huma.Error409Conflict("an fstab entry already exists for " + e.Mountpoint)
@@ -158,13 +163,13 @@ func registerStorage(api huma.API) {
 
 		entries, err := readFstab()
 		if err != nil {
-			return nil, huma.Error500InternalServerError("read fstab failed", err)
+			return nil, huma.Error500InternalServerError("fstab lookup failed", err)
 		}
 		inFstab := findEntry(entries, in.Mountpoint) != nil
 
 		mounted, err := isMounted(in.Mountpoint)
 		if err != nil {
-			return nil, huma.Error500InternalServerError("read mounts failed", err)
+			return nil, huma.Error500InternalServerError("mount table lookup failed", err)
 		}
 		if !inFstab && !mounted {
 			return nil, huma.Error404NotFound("no mount or fstab entry for " + in.Mountpoint)
@@ -231,8 +236,25 @@ func renderFstabLine(e FstabEntry) string {
 	return fmt.Sprintf("%s\t%s\t%s\t%s\t%d\t%d", e.Device, e.Mountpoint, e.FSType, e.Options, e.Dump, e.Pass)
 }
 
+// writeFstabAtomically writes content to /etc/fstab using a temporary file and
+// rename, so a crash mid-write leaves the original file intact.
+func writeFstabAtomically(content string) error {
+	tmp := fstabFile + ".nadir.tmp"
+	if err := os.WriteFile(tmp, []byte(content), 0644); err != nil {
+		return err
+	}
+	if err := os.Rename(tmp, fstabFile); err != nil {
+		os.Remove(tmp)
+		return err
+	}
+	return nil
+}
+
 // appendFstabLine adds one entry, leaving every existing line untouched.
 func appendFstabLine(e FstabEntry) error {
+	fstabMu.Lock()
+	defer fstabMu.Unlock()
+
 	data, err := os.ReadFile(fstabFile)
 	if err != nil {
 		return err
@@ -242,12 +264,15 @@ func appendFstabLine(e FstabEntry) error {
 		content += "\n"
 	}
 	content += renderFstabLine(e) + "\n"
-	return os.WriteFile(fstabFile, []byte(content), 0644)
+	return writeFstabAtomically(content)
 }
 
 // removeFstabLines drops every line mapping mountpoint, preserving comments and
 // other entries. Reports whether anything was removed.
 func removeFstabLines(mountpoint string) (bool, error) {
+	fstabMu.Lock()
+	defer fstabMu.Unlock()
+
 	data, err := os.ReadFile(fstabFile)
 	if err != nil {
 		return false, err
@@ -268,7 +293,7 @@ func removeFstabLines(mountpoint string) (bool, error) {
 	if !removed {
 		return false, nil
 	}
-	return true, os.WriteFile(fstabFile, []byte(strings.Join(kept, "\n")), 0644)
+	return true, writeFstabAtomically(strings.Join(kept, "\n"))
 }
 
 func findEntry(entries []FstabEntry, mountpoint string) *FstabEntry {

internal/modules/storage/storage_test.go

@@ -79,23 +79,27 @@ func mustReadFstab(t *testing.T) []FstabEntry {
 }
 
 func TestValidateEntry(t *testing.T) {
-	ok := FstabEntry{Device: "/dev/sdb1", Mountpoint: "/mnt/data", FSType: "ext4", Options: "defaults"}
-	if err := validateEntry(ok); err != nil {
-		t.Errorf("valid entry rejected: %v", err)
-	}
-	if err := validateEntry(FstabEntry{Device: "UUID=ab-cd", Mountpoint: "/mnt/x", FSType: "xfs", Options: "rw,noatime"}); err != nil {
-		t.Errorf("UUID entry rejected: %v", err)
-	}
-	bad := []FstabEntry{
-		{Device: "/dev/sdb1; rm -rf /", Mountpoint: "/mnt/x", FSType: "ext4", Options: "defaults"}, // shell metachars
-		{Device: "/dev/sdb1", Mountpoint: "../etc", FSType: "ext4", Options: "defaults"},           // not absolute
-		{Device: "/dev/sdb1", Mountpoint: "/mnt/../../etc", FSType: "ext4", Options: "defaults"},   // traversal
-		{Device: "/dev/sdb1", Mountpoint: "/mnt/x", FSType: "ext4!", Options: "defaults"},          // bad fstype
-		{Device: "/dev/sdb1", Mountpoint: "/mnt/x", FSType: "ext4", Options: "defaults; reboot"},   // bad options
-	}
-	for i, e := range bad {
-		if err := validateEntry(e); err == nil {
-			t.Errorf("bad entry %d accepted: %+v", i, e)
-		}
+	for _, tt := range []struct {
+		name  string
+		entry FstabEntry
+		valid bool
+	}{
+		{name: "valid", entry: FstabEntry{Device: "/dev/sdb1", Mountpoint: "/mnt/data", FSType: "ext4", Options: "defaults"}, valid: true},
+		{name: "UUID", entry: FstabEntry{Device: "UUID=ab-cd", Mountpoint: "/mnt/x", FSType: "xfs", Options: "rw,noatime"}, valid: true},
+		{name: "shell metachar in device", entry: FstabEntry{Device: "/dev/sdb1; rm -rf /", Mountpoint: "/mnt/x", FSType: "ext4", Options: "defaults"}, valid: false},
+		{name: "relative mountpoint", entry: FstabEntry{Device: "/dev/sdb1", Mountpoint: "../etc", FSType: "ext4", Options: "defaults"}, valid: false},
+		{name: "traversal in mountpoint", entry: FstabEntry{Device: "/dev/sdb1", Mountpoint: "/mnt/../../etc", FSType: "ext4", Options: "defaults"}, valid: false},
+		{name: "bad fstype", entry: FstabEntry{Device: "/dev/sdb1", Mountpoint: "/mnt/x", FSType: "ext4!", Options: "defaults"}, valid: false},
+		{name: "bad options", entry: FstabEntry{Device: "/dev/sdb1", Mountpoint: "/mnt/x", FSType: "ext4", Options: "defaults; reboot"}, valid: false},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			err := validateEntry(tt.entry)
+			if tt.valid && err != nil {
+				t.Errorf("valid entry rejected: %v", err)
+			}
+			if !tt.valid && err == nil {
+				t.Errorf("bad entry accepted: %+v", tt.entry)
+			}
+		})
 	}
 }

internal/modules/system/cpu.go

@@ -0,0 +1,146 @@
+package system
+
+import (
+	"math"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strconv"
+	"strings"
+
+	"nadir/internal/oscmd"
+)
+
+type CPUInfo struct {
+	Model       string `json:"model" example:"AMD Ryzen 7 7840U" doc:"CPU model name"`
+	LogicalCPUs int    `json:"logical_cpus" example:"16" doc:"Number of logical CPUs (cores × threads)"`
+	MinMHz      int    `json:"min_mhz" example:"400" doc:"Lowest frequency the scaling governor can select"`
+	MaxMHz      int    `json:"max_mhz" example:"5137" doc:"Highest frequency (boost ceiling)"`
+	CurrentMHz  int    `json:"current_mhz" example:"3157" doc:"Peak current clock across all cores (instantaneous snapshot; 0 if cpufreq unavailable)"`
+}
+
+func cpuInfo() CPUInfo {
+	data, _ := os.ReadFile("/proc/cpuinfo")
+	c := CPUInfo{Model: cpuModel(string(data)), LogicalCPUs: runtime.NumCPU()}
+	c.MinMHz, c.MaxMHz, c.CurrentMHz = cpuFreqMHz("/sys/devices/system/cpu")
+	mhz := cpuinfoMaxMHz(string(data))
+	if c.Model == "" || mhz == 0 {
+		model, lscpuMHz := lscpuFallback()
+		if c.Model == "" {
+			c.Model = model
+		}
+		if mhz == 0 {
+			mhz = lscpuMHz
+		}
+	}
+	if mhz > 0 {
+		if c.CurrentMHz == 0 {
+			c.CurrentMHz = mhz
+		}
+		if c.MaxMHz == 0 {
+			c.MaxMHz = mhz
+		}
+		if c.MinMHz == 0 {
+			c.MinMHz = mhz
+		}
+	}
+	return c
+}
+
+func lscpuFallback() (model string, mhz int) {
+	out, err := oscmd.Run("lscpu")
+	if err != nil {
+		return "", 0
+	}
+	for line := range strings.SplitSeq(out, "\n") {
+		k, v, ok := strings.Cut(line, ":")
+		if !ok {
+			continue
+		}
+		k, v = strings.TrimSpace(k), strings.TrimSpace(v)
+		switch k {
+		case "Model name":
+			if model == "" {
+				model = v
+			}
+		case "BIOS Model name":
+			if model == "" {
+				model = v
+			}
+		case "CPU max MHz", "CPU MHz":
+			if f, err := strconv.ParseFloat(v, 64); err == nil && int(f) > mhz {
+				mhz = int(math.Round(f))
+			}
+		}
+	}
+	if mhz == 0 {
+		mhz = parseGHzSuffix(model)
+	}
+	return model, mhz
+}
+
+func parseGHzSuffix(s string) int {
+	i := strings.LastIndex(s, "@")
+	if i < 0 {
+		return 0
+	}
+	rest := strings.TrimSpace(s[i+1:])
+	rest = strings.TrimSuffix(strings.TrimSuffix(rest, "GHz"), "Ghz")
+	rest = strings.TrimSpace(strings.TrimSuffix(rest, "G"))
+	f, err := strconv.ParseFloat(strings.TrimSpace(rest), 64)
+	if err != nil {
+		return 0
+	}
+	return int(math.Round(f * 1000))
+}
+
+func cpuinfoMaxMHz(cpuinfo string) int {
+	var max float64
+	for line := range strings.SplitSeq(cpuinfo, "\n") {
+		k, v, ok := strings.Cut(line, ":")
+		if !ok || strings.TrimSpace(k) != "cpu MHz" {
+			continue
+		}
+		if f, err := strconv.ParseFloat(strings.TrimSpace(v), 64); err == nil && f > max {
+			max = f
+		}
+	}
+	return int(math.Round(max))
+}
+
+func cpuFreqMHz(root string) (min, max, cur int) {
+	min = readKHzAsMHz(filepath.Join(root, "cpu0/cpufreq/cpuinfo_min_freq"))
+	max = readKHzAsMHz(filepath.Join(root, "cpu0/cpufreq/cpuinfo_max_freq"))
+	cores, _ := filepath.Glob(filepath.Join(root, "cpu[0-9]*/cpufreq/scaling_cur_freq"))
+	for _, f := range cores {
+		if v := readKHzAsMHz(f); v > cur {
+			cur = v
+		}
+	}
+	return min, max, cur
+}
+
+func readKHzAsMHz(path string) int {
+	khz, err := strconv.Atoi(readTrim(path))
+	if err != nil {
+		return 0
+	}
+	return khz / 1000
+}
+
+func cpuModel(cpuinfo string) string {
+	var fallback string
+	for line := range strings.SplitSeq(cpuinfo, "\n") {
+		k, v, ok := strings.Cut(line, ":")
+		if !ok {
+			continue
+		}
+		switch strings.TrimSpace(k) {
+		case "model name":
+			return strings.TrimSpace(v)
+		case "Model":
+			fallback = strings.TrimSpace(v)
+		}
+	}
+	return fallback
+}

internal/modules/system/cpustat.go

@@ -0,0 +1,137 @@
+package system
+
+import (
+	"context"
+	"math"
+	"os"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+)
+
+// Sampler samples /proc/stat periodically and caches per-core CPU usage
+// percentages. Create with New, start the background goroutine with Start, and
+// read the latest snapshot with Snapshot.
+type Sampler struct {
+	statPath string
+	interval time.Duration
+	mu       sync.RWMutex
+	cache    []CoreUsage
+	once     sync.Once
+}
+
+// NewSampler creates a Sampler that reads statPath and samples every interval.
+func NewSampler(statPath string, interval time.Duration) *Sampler {
+	return &Sampler{statPath: statPath, interval: interval}
+}
+
+// Start launches the background sampling goroutine. Only the first call starts
+// it; subsequent calls are no-ops. The goroutine exits when ctx is cancelled.
+func (s *Sampler) Start(ctx context.Context) {
+	s.once.Do(func() {
+		go s.loop(ctx)
+	})
+}
+
+// Snapshot returns a copy of the latest per-core usage snapshot. Returns nil
+// before the first sample completes.
+func (s *Sampler) Snapshot() []CoreUsage {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	if s.cache == nil {
+		return nil
+	}
+	out := make([]CoreUsage, len(s.cache))
+	copy(out, s.cache)
+	return out
+}
+
+func (s *Sampler) loop(ctx context.Context) {
+	prev := readProcStat(s.statPath)
+	ticker := time.NewTicker(s.interval)
+	defer ticker.Stop()
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-ticker.C:
+			cur := readProcStat(s.statPath)
+			usage := computeUsage(prev, cur)
+			s.mu.Lock()
+			s.cache = usage
+			s.mu.Unlock()
+			prev = cur
+		}
+	}
+}
+
+// cpuCoreTicks holds the cumulative jiffies for one "cpuN" line.
+type cpuCoreTicks struct {
+	core  int
+	total uint64
+	idle  uint64
+}
+
+// readProcStat reads /proc/stat and returns per-core tick totals. The
+// aggregate "cpu" line (no digit suffix) is skipped.
+func readProcStat(path string) []cpuCoreTicks {
+	data, _ := os.ReadFile(path)
+	var cores []cpuCoreTicks
+	for line := range strings.SplitSeq(string(data), "\n") {
+		if !strings.HasPrefix(line, "cpu") {
+			continue
+		}
+		fields := strings.Fields(line)
+		if len(fields) < 5 {
+			continue
+		}
+		name := fields[0]
+		if name == "cpu" {
+			continue
+		}
+		coreIdx, err := strconv.Atoi(strings.TrimPrefix(name, "cpu"))
+		if err != nil {
+			continue
+		}
+		var total, idle uint64
+		for _, f := range fields[1:] {
+			v, _ := strconv.ParseUint(f, 10, 64)
+			total += v
+		}
+		if len(fields) > 5 {
+			v4, _ := strconv.ParseUint(fields[4], 10, 64)
+			v5, _ := strconv.ParseUint(fields[5], 10, 64)
+			idle = v4 + v5
+		} else {
+			v4, _ := strconv.ParseUint(fields[4], 10, 64)
+			idle = v4
+		}
+		cores = append(cores, cpuCoreTicks{core: coreIdx, total: total, idle: idle})
+	}
+	return cores
+}
+
+// computeUsage converts two snapshots into per-core usage percentages.
+func computeUsage(prev, cur []cpuCoreTicks) []CoreUsage {
+	prevMap := make(map[int]cpuCoreTicks, len(prev))
+	for _, c := range prev {
+		prevMap[c.core] = c
+	}
+	usage := make([]CoreUsage, 0, len(cur))
+	for _, c := range cur {
+		p, ok := prevMap[c.core]
+		if !ok {
+			continue
+		}
+		dTotal := c.total - p.total
+		dIdle := c.idle - p.idle
+		var pct float64
+		if dTotal > 0 {
+			pct = float64(dTotal-dIdle) / float64(dTotal) * 100
+			pct = math.Round(pct*10) / 10
+		}
+		usage = append(usage, CoreUsage{Core: c.core, UsagePct: pct})
+	}
+	return usage
+}

internal/modules/system/cpustat_test.go

@@ -0,0 +1,134 @@
+package system
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"reflect"
+	"testing"
+	"time"
+)
+
+func TestNewSampler(t *testing.T) {
+	s := NewSampler("/proc/stat", time.Second)
+	if s == nil {
+		t.Fatal("NewSampler returned nil")
+	}
+	if s.statPath != "/proc/stat" {
+		t.Errorf("statPath = %q, want /proc/stat", s.statPath)
+	}
+	if s.interval != time.Second {
+		t.Errorf("interval = %v, want 1s", s.interval)
+	}
+}
+
+func TestSamplerSnapshotsRealProcStat(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	s := NewSampler("/proc/stat", 10*time.Millisecond)
+	s.Start(ctx)
+	// Wait for at least two samples so there is a delta to compute.
+	time.Sleep(50 * time.Millisecond)
+
+	snap := s.Snapshot()
+	if snap == nil {
+		t.Fatal("Snapshot returned nil (expected at least one sample)")
+	}
+	if len(snap) == 0 {
+		t.Fatal("Snapshot returned empty (expected at least one core)")
+	}
+	for _, c := range snap {
+		if c.UsagePct < 0 || c.UsagePct > 100 {
+			t.Errorf("core %d: usage_pct = %f, want 0–100", c.Core, c.UsagePct)
+		}
+	}
+}
+
+func TestSamplerReturnsCopy(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	s := NewSampler("/proc/stat", 10*time.Millisecond)
+	s.Start(ctx)
+	time.Sleep(50 * time.Millisecond)
+
+	snap1 := s.Snapshot()
+	snap2 := s.Snapshot()
+
+	// Both should be non-nil and deep-equal.
+	if snap1 == nil || snap2 == nil {
+		t.Fatal("Snapshot returned nil")
+	}
+	if !reflect.DeepEqual(snap1, snap2) {
+		t.Error("two sequential snapshots should be deep-equal")
+	}
+
+	// Mutating the returned slice should not affect the sampler.
+	if len(snap1) > 0 {
+		snap1[0].UsagePct = 999
+		if snap2[0].UsagePct == 999 {
+			t.Error("mutating one snapshot affected the other — expected a copy")
+		}
+	}
+}
+
+func TestSamplerStartOnce(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	s := NewSampler("/proc/stat", 10*time.Millisecond)
+	s.Start(ctx)
+	s.Start(ctx) // second call must not panic or create a second goroutine
+	time.Sleep(30 * time.Millisecond)
+
+	if snap := s.Snapshot(); snap == nil {
+		t.Fatal("Snapshot returned nil after Start")
+	}
+}
+
+func TestSamplerContextCancelStopsGoroutine(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	s := NewSampler("/proc/stat", 10*time.Millisecond)
+	s.Start(ctx)
+
+	time.Sleep(30 * time.Millisecond)
+	if snap := s.Snapshot(); snap == nil {
+		t.Fatal("Snapshot returned nil before cancel")
+	}
+
+	cancel()
+	// Give the goroutine time to exit. If it doesn't, the test will hang.
+	time.Sleep(20 * time.Millisecond)
+	// Snapshot should still return the last cached value (no panic).
+	if snap := s.Snapshot(); snap == nil {
+		t.Fatal("Snapshot returned nil after cancel (cache should persist)")
+	}
+}
+
+func TestSamplerWithFakeStat(t *testing.T) {
+	dir := t.TempDir()
+	statPath := filepath.Join(dir, "stat")
+	content := []byte("cpu  100 20 30 400 10 5 3 2 0 0\ncpu0 50 10 15 200 5 3 1 1 0 0\ncpu1 50 10 15 200 5 2 2 1 0 0\n")
+	if err := os.WriteFile(statPath, content, 0o644); err != nil {
+		t.Fatal(err)
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	s := NewSampler(statPath, 20*time.Millisecond)
+	s.Start(ctx)
+	time.Sleep(50 * time.Millisecond)
+
+	snap := s.Snapshot()
+	if snap == nil {
+		t.Fatal("Snapshot returned nil")
+	}
+	// With the stat file not changing between reads, deltas are zero → 0% usage.
+	for _, c := range snap {
+		if c.UsagePct != 0 {
+			t.Errorf("core %d: expected 0%% usage (static stat file), got %f", c.Core, c.UsagePct)
+		}
+	}
+}

internal/modules/system/disks.go

@@ -0,0 +1,73 @@
+package system
+
+import (
+	"syscall"
+
+	"nadir/internal/mounts"
+)
+
+type DiskInfo struct {
+	Mountpoint string `json:"mountpoint" example:"/"`
+	Filesystem string `json:"filesystem" example:"/dev/nvme0n1p2" doc:"Backing device"`
+	FSType     string `json:"fstype" example:"btrfs"`
+	TotalBytes uint64 `json:"total_bytes" example:"512000000000"`
+	FreeBytes  uint64 `json:"free_bytes" example:"256000000000" doc:"Space available to unprivileged users"`
+	UsedBytes  uint64 `json:"used_bytes" example:"256000000000"`
+}
+
+func diskInfo() []DiskInfo {
+	entries, err := mounts.Proc()
+	if err != nil {
+		return nil
+	}
+	disks := []DiskInfo{}
+	seen := map[string]bool{}
+	for _, e := range entries {
+		if pseudoFS[e.FSType] || seen[e.Mountpoint] {
+			continue
+		}
+		var st syscall.Statfs_t
+		if syscall.Statfs(e.Mountpoint, &st) != nil || st.Blocks == 0 {
+			continue
+		}
+		seen[e.Mountpoint] = true
+		bs := uint64(st.Bsize)
+		disks = append(disks, DiskInfo{
+			Mountpoint: e.Mountpoint,
+			Filesystem: e.Device,
+			FSType:     e.FSType,
+			TotalBytes: st.Blocks * bs,
+			FreeBytes:  st.Bavail * bs,
+			UsedBytes:  (st.Blocks - st.Bfree) * bs,
+		})
+	}
+	return disks
+}
+
+var pseudoFS = map[string]bool{
+	"autofs":           true,
+	"binfmt_misc":      true,
+	"bpf":              true,
+	"cgroup":           true,
+	"cgroup2":          true,
+	"configfs":         true,
+	"debugfs":          true,
+	"devpts":           true,
+	"devtmpfs":         true,
+	"fuse.gvfsd-fuse":  true,
+	"fuse.lxcfs":       true,
+	"fusectl":          true,
+	"hugetlbfs":        true,
+	"mqueue":           true,
+	"nsfs":             true,
+	"overlay":          true,
+	"proc":             true,
+	"pstore":           true,
+	"ramfs":            true,
+	"rpc_pipefs":       true,
+	"securityfs":       true,
+	"squashfs":         true,
+	"sysfs":            true,
+	"tmpfs":            true,
+	"tracefs":          true,
+}

internal/modules/system/gpu.go

@@ -0,0 +1,187 @@
+package system
+
+import (
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+
+	"nadir/internal/oscmd"
+)
+
+type GPUInfo struct {
+	Model             string  `json:"model" example:"AMD Radeon RX 7900 XTX" doc:"GPU model name, or vendor:device hex ID if lspci unavailable"`
+	Vendor            string  `json:"vendor" example:"1002" doc:"PCI vendor ID (hex)"`
+	DeviceID          string  `json:"device_id" example:"744c" doc:"PCI device ID (hex)"`
+	Driver            string  `json:"driver" example:"amdgpu" doc:"Kernel driver in use"`
+	MemoryTotalBytes  uint64  `json:"memory_total_bytes" example:"8589934592" doc:"Total VRAM in bytes (driver-dependent; 0 if unavailable)"`
+	MemoryUsedBytes   uint64  `json:"memory_used_bytes" example:"27267072" doc:"Used VRAM in bytes (driver-dependent; 0 if unavailable)"`
+	UtilizationPct    float64 `json:"utilization_pct" example:"23.5" doc:"GPU compute utilization percentage (driver-dependent; 0 if unavailable)"`
+	MemUtilizationPct float64 `json:"mem_utilization_pct" example:"15.0" doc:"GPU memory controller utilization percentage (driver-dependent; 0 if unavailable)"`
+}
+
+func gpuInfo() []GPUInfo {
+	return readGPUsFromSysfs("/sys/class/drm")
+}
+
+func readGPUsFromSysfs(drmRoot string) []GPUInfo {
+	entries, err := os.ReadDir(drmRoot)
+	if err != nil {
+		return nil
+	}
+
+	seen := map[string]bool{}
+	var gpus []GPUInfo
+
+	for _, e := range entries {
+		if !isGPUCard(e.Name()) {
+			continue
+		}
+
+		pciAddr, vendor, device, driver := readGPUFromCard(drmRoot, e.Name())
+		if pciAddr == "" || seen[pciAddr] {
+			continue
+		}
+		seen[pciAddr] = true
+
+		model := vendor + ":" + device
+		if m := lookupGPUName(pciAddr); m != "" {
+			model = m
+		}
+
+		gpu := GPUInfo{
+			Model:    model,
+			Vendor:   vendor,
+			DeviceID: device,
+			Driver:   driver,
+		}
+
+		devPath := filepath.Join(drmRoot, e.Name(), "device")
+		enrichGPUInfo(&gpu, devPath, pciAddr, driver)
+		gpus = append(gpus, gpu)
+	}
+
+	return gpus
+}
+
+func enrichGPUInfo(gpu *GPUInfo, devPath, pciAddr, driver string) {
+	switch driver {
+	case "amdgpu":
+		enrichAMDGPU(gpu, devPath)
+	case "nvidia":
+		enrichNvidiaGPU(gpu, pciAddr)
+	}
+}
+
+func enrichAMDGPU(gpu *GPUInfo, devPath string) {
+	if total := readUint64FromFile(filepath.Join(devPath, "mem_info_vram_total")); total > 0 {
+		gpu.MemoryTotalBytes = total
+		gpu.MemoryUsedBytes = readUint64FromFile(filepath.Join(devPath, "mem_info_vram_used"))
+	}
+	if pct := readIntFromFile(filepath.Join(devPath, "gpu_busy_percent")); pct >= 0 {
+		gpu.UtilizationPct = float64(pct)
+	}
+	if pct := readIntFromFile(filepath.Join(devPath, "mem_busy_percent")); pct >= 0 {
+		gpu.MemUtilizationPct = float64(pct)
+	}
+}
+
+func enrichNvidiaGPU(gpu *GPUInfo, pciAddr string) {
+	out, err := oscmd.Run("nvidia-smi",
+		"-i", pciAddr,
+		"--query-gpu=memory.total,memory.used,utilization.gpu,utilization.memory",
+		"--format=csv,noheader,nounits",
+	)
+	if err != nil {
+		return
+	}
+	parts := strings.Split(strings.TrimSpace(out), ", ")
+	if len(parts) < 4 {
+		return
+	}
+	if total, err := strconv.ParseUint(parts[0], 10, 64); err == nil && total > 0 {
+		gpu.MemoryTotalBytes = total * 1024 * 1024
+		if used, err := strconv.ParseUint(parts[1], 10, 64); err == nil {
+			gpu.MemoryUsedBytes = used * 1024 * 1024
+		}
+	}
+	if pct, err := strconv.ParseFloat(parts[2], 64); err == nil {
+		gpu.UtilizationPct = pct
+	}
+	if pct, err := strconv.ParseFloat(parts[3], 64); err == nil {
+		gpu.MemUtilizationPct = pct
+	}
+}
+
+func isGPUCard(name string) bool {
+	if !strings.HasPrefix(name, "card") {
+		return false
+	}
+	if len(name) == 4 {
+		return false
+	}
+	ch := name[4]
+	return ch >= '0' && ch <= '9'
+}
+
+func readGPUFromCard(drmRoot, name string) (pciAddr, vendor, device, driver string) {
+	cardPath := filepath.Join(drmRoot, name)
+	devPath := filepath.Join(cardPath, "device")
+
+	resolved, err := filepath.EvalSymlinks(cardPath)
+	if err != nil {
+		return "", "", "", ""
+	}
+
+	parts := strings.Split(resolved, "/")
+	for i, p := range parts {
+		if p == "drm" && i > 0 {
+			pciAddr = parts[i-1]
+			break
+		}
+	}
+	if pciAddr == "" {
+		return "", "", "", ""
+	}
+
+	vendor = strings.TrimPrefix(readTrim(filepath.Join(devPath, "vendor")), "0x")
+	device = strings.TrimPrefix(readTrim(filepath.Join(devPath, "device")), "0x")
+	driver = readDriver(devPath)
+	return
+}
+
+func readDriver(devPath string) string {
+	target, err := os.Readlink(filepath.Join(devPath, "driver"))
+	if err != nil {
+		return ""
+	}
+	return filepath.Base(target)
+}
+
+func lookupGPUName(pciAddr string) string {
+	out, err := oscmd.Run("lspci", "-nns", pciAddr)
+	if err != nil {
+		return ""
+	}
+	_, rest, ok := strings.Cut(out, " ")
+	if !ok {
+		return ""
+	}
+	return strings.TrimSpace(rest)
+}
+
+func readUint64FromFile(path string) uint64 {
+	v, err := strconv.ParseUint(readTrim(path), 10, 64)
+	if err != nil {
+		return 0
+	}
+	return v
+}
+
+func readIntFromFile(path string) int {
+	v, err := strconv.Atoi(readTrim(path))
+	if err != nil {
+		return -1
+	}
+	return v
+}

internal/modules/system/info.go

@@ -2,26 +2,16 @@ package system
 
 import (
 	"context"
-	"math"
-	"net"
 	"os"
-	"os/exec"
-	"path/filepath"
-	"runtime"
 	"strconv"
 	"strings"
-	"sync"
-	"syscall"
 	"time"
 
-	"nadir/internal/mounts"
-	"nadir/internal/oscmd"
-
 	"github.com/danielgtaylor/huma/v2"
 )
 
 // SystemInfoBody is the dashboard overview: OS identity plus live CPU, memory,
-// disk, load, network, and temperature readings. Every section is best-effort —
+// disk, load, network, GPU, and temperature readings. Every section is best-effort —
 // a source that's unavailable (e.g. no thermal zones in a VM) yields a zero
 // value or empty list rather than failing the whole call.
 type SystemInfoBody struct {
@@ -34,71 +24,12 @@ type SystemInfoBody struct {
 	Disks             []DiskInfo     `json:"disks" doc:"Mounted block-device filesystems"`
 	NetworkInterfaces []NetInterface `json:"network_interfaces" doc:"Network interfaces and their addresses"`
 	Temperatures      []Temperature  `json:"temperatures" doc:"Thermal sensor readings in Celsius"`
-}
-
-type OSInfo struct {
-	PrettyName   string `json:"pretty_name" example:"Fedora Linux 44 (Workstation Edition)" doc:"Distro name from /etc/os-release PRETTY_NAME"`
-	Kernel       string `json:"kernel" example:"7.0.12-201.fc44.x86_64" doc:"Running kernel release (uname -r)"`
-	Architecture string `json:"architecture" example:"x86_64" doc:"Machine hardware architecture (uname -m)"`
-	Hostname     string `json:"hostname" example:"server01" doc:"System hostname"`
-}
-
-type CPUInfo struct {
-	Model       string `json:"model" example:"AMD Ryzen 7 7840U" doc:"CPU model name"`
-	LogicalCPUs int    `json:"logical_cpus" example:"16" doc:"Number of logical CPUs (cores × threads)"`
-	MinMHz      int    `json:"min_mhz" example:"400" doc:"Lowest frequency the scaling governor can select"`
-	MaxMHz      int    `json:"max_mhz" example:"5137" doc:"Highest frequency (boost ceiling)"`
-	CurrentMHz  int    `json:"current_mhz" example:"3157" doc:"Peak current clock across all cores (instantaneous snapshot; 0 if cpufreq unavailable)"`
-}
-
-type MemoryInfo struct {
-	TotalBytes     uint64 `json:"total_bytes" example:"16384000000"`
-	AvailableBytes uint64 `json:"available_bytes" example:"8192000000" doc:"Memory available for new allocations without swapping"`
-	UsedBytes      uint64 `json:"used_bytes" example:"8192000000" doc:"total - available"`
-	SwapTotalBytes uint64 `json:"swap_total_bytes" example:"8589934592"`
-	SwapFreeBytes  uint64 `json:"swap_free_bytes" example:"8589934592"`
-}
-
-type LoadInfo struct {
-	Load1    float64     `json:"load1" example:"0.42"`
-	Load5    float64     `json:"load5" example:"0.55"`
-	Load15   float64     `json:"load15" example:"0.61"`
-	CPUUsage []CoreUsage `json:"cpu_usage" doc:"Per-core CPU usage percentage (sampled over ~1 s); empty until the first sample completes"`
-}
-
-// CoreUsage holds the usage percentage for a single logical core, computed as
-// the delta of non-idle ticks over total ticks between two /proc/stat reads.
-type CoreUsage struct {
-	Core    int     `json:"core" example:"0" doc:"Logical core index"`
-	UsagePct float64 `json:"usage_pct" example:"23.4" doc:"Usage percentage (0–100)"`
-}
-
-type DiskInfo struct {
-	Mountpoint string `json:"mountpoint" example:"/"`
-	Filesystem string `json:"filesystem" example:"/dev/nvme0n1p2" doc:"Backing device"`
-	FSType     string `json:"fstype" example:"btrfs"`
-	TotalBytes uint64 `json:"total_bytes" example:"512000000000"`
-	FreeBytes  uint64 `json:"free_bytes" example:"256000000000" doc:"Space available to unprivileged users"`
-	UsedBytes  uint64 `json:"used_bytes" example:"256000000000"`
-}
-
-type NetInterface struct {
-	Name      string   `json:"name" example:"eth0"`
-	MAC       string   `json:"mac" example:"aa:bb:cc:dd:ee:ff"`
-	Up        bool     `json:"up" doc:"Interface is administratively up"`
-	Addresses []string `json:"addresses" doc:"Assigned addresses in CIDR notation"`
-}
-
-type Temperature struct {
-	Chip    string  `json:"chip" example:"k10temp" doc:"hwmon chip name; identifies the source (k10temp/coretemp=CPU, amdgpu/nvidia=GPU, nvme=disk)"`
-	Label   string  `json:"label" example:"Tctl" doc:"Per-sensor label, or the chip name when the sensor is unlabelled"`
-	Celsius float64 `json:"celsius" example:"47.5"`
+	GPUs              []GPUInfo      `json:"gpus" doc:"Graphics processors detected via DRM sysfs"`
 }
 
 type GetInfoOutput struct{ Body SystemInfoBody }
 
-func registerInfo(api huma.API) {
-	startCPUSampler()
+func registerInfo(api huma.API, sampler *Sampler) {
 	huma.Register(api, huma.Operation{
 		OperationID: "system-get-info",
 		Method:      "GET",
@@ -106,9 +37,9 @@ func registerInfo(api huma.API) {
 		Summary:     "Get system information",
 		Description: "Returns an overview for a dashboard: OS/kernel identity, CPU, " +
 			"memory and swap, mounted disks, load averages, uptime, network " +
-			"interfaces, and temperatures. All values come from cheap local reads " +
-			"(/proc, /sys, syscalls) with no D-Bus dependency; each section is " +
-			"best-effort.",
+			"interfaces, temperatures, and GPU information. All values come from cheap " +
+			"local reads (/proc, /sys, syscalls) with no D-Bus dependency; each " +
+			"section is best-effort.",
 		Tags:     []string{tagSystem},
 		Metadata: op("read"),
 		Errors:   readErrors,
@@ -118,360 +49,17 @@ func registerInfo(api huma.API) {
 			OS:                osInfo(),
 			CPU:               cpuInfo(),
 			Memory:            memInfo(),
-			Load:              loadInfo(),
+			Load:              loadInfo(sampler),
 			UptimeSec:         uptime,
 			BootTime:          boot.Format(time.RFC3339),
 			Disks:             diskInfo(),
 			NetworkInterfaces: netInfo(),
 			Temperatures:      tempInfo(),
+			GPUs:              gpuInfo(),
 		}}, nil
 	})
 }
 
-func osInfo() OSInfo {
-	host, _ := os.Hostname()
-	return OSInfo{
-		PrettyName:   osReleasePretty(),
-		Kernel:       firstLine(oscmd.Run("uname", "-r")),
-		Architecture: firstLine(oscmd.Run("uname", "-m")),
-		Hostname:     host,
-	}
-}
-
-// firstLine discards a command error and returns its (already trimmed) output,
-// used where a missing value is acceptable.
-func firstLine(out string, _ error) string { return out }
-
-func osReleasePretty() string {
-	data, err := os.ReadFile("/etc/os-release")
-	if err != nil {
-		return ""
-	}
-	for line := range strings.SplitSeq(string(data), "\n") {
-		if v, ok := strings.CutPrefix(line, "PRETTY_NAME="); ok {
-			return strings.Trim(v, `"`)
-		}
-	}
-	return ""
-}
-
-func cpuInfo() CPUInfo {
-	data, _ := os.ReadFile("/proc/cpuinfo")
-	c := CPUInfo{Model: cpuModel(string(data)), LogicalCPUs: runtime.NumCPU()}
-	c.MinMHz, c.MaxMHz, c.CurrentMHz = cpuFreqMHz("/sys/devices/system/cpu")
-	// ponytail: cpufreq sysfs is absent on many VMs and stock Ubuntu server
-	// kernels; fall back to /proc/cpuinfo "cpu MHz" — VMs have a fixed clock,
-	// so min == max == cur is the honest answer.
-	mhz := cpuinfoMaxMHz(string(data))
-	// ponytail: ARM /proc/cpuinfo has no "cpu MHz" and often no "model name";
-	// lscpu decodes the ARM part-id table and reads DMI, so use it as last resort.
-	if c.Model == "" || mhz == 0 {
-		model, lscpuMHz := lscpuFallback()
-		if c.Model == "" {
-			c.Model = model
-		}
-		if mhz == 0 {
-			mhz = lscpuMHz
-		}
-	}
-	if mhz > 0 {
-		if c.CurrentMHz == 0 {
-			c.CurrentMHz = mhz
-		}
-		if c.MaxMHz == 0 {
-			c.MaxMHz = mhz
-		}
-		if c.MinMHz == 0 {
-			c.MinMHz = mhz
-		}
-	}
-	return c
-}
-
-// lscpuFallback parses `lscpu` for "Model name" and any embedded "@ X.X GHz"
-// or "CPU max MHz:" value. Returns zeros when lscpu is missing or silent.
-func lscpuFallback() (model string, mhz int) {
-	out, err := exec.Command("lscpu").Output()
-	if err != nil {
-		return "", 0
-	}
-	for line := range strings.SplitSeq(string(out), "\n") {
-		k, v, ok := strings.Cut(line, ":")
-		if !ok {
-			continue
-		}
-		k, v = strings.TrimSpace(k), strings.TrimSpace(v)
-		switch k {
-		case "Model name":
-			if model == "" {
-				model = v
-			}
-		case "BIOS Model name":
-			if model == "" {
-				model = v
-			}
-		case "CPU max MHz", "CPU MHz":
-			if f, err := strconv.ParseFloat(v, 64); err == nil && int(f) > mhz {
-				mhz = int(math.Round(f))
-			}
-		}
-	}
-	if mhz == 0 {
-		mhz = parseGHzSuffix(model)
-	}
-	return model, mhz
-}
-
-// parseGHzSuffix pulls "2.0GHz" / "@ 2.0 GHz" out of a model string.
-func parseGHzSuffix(s string) int {
-	i := strings.LastIndex(s, "@")
-	if i < 0 {
-		return 0
-	}
-	rest := strings.TrimSpace(s[i+1:])
-	rest = strings.TrimSuffix(strings.TrimSuffix(rest, "GHz"), "Ghz")
-	rest = strings.TrimSpace(strings.TrimSuffix(rest, "G"))
-	f, err := strconv.ParseFloat(strings.TrimSpace(rest), 64)
-	if err != nil {
-		return 0
-	}
-	return int(math.Round(f * 1000))
-}
-
-// cpuinfoMaxMHz returns the highest "cpu MHz" value across all cores in
-// /proc/cpuinfo, rounded to an int. Returns 0 when no such line exists.
-func cpuinfoMaxMHz(cpuinfo string) int {
-	var max float64
-	for line := range strings.SplitSeq(cpuinfo, "\n") {
-		k, v, ok := strings.Cut(line, ":")
-		if !ok || strings.TrimSpace(k) != "cpu MHz" {
-			continue
-		}
-		if f, err := strconv.ParseFloat(strings.TrimSpace(v), 64); err == nil && f > max {
-			max = f
-		}
-	}
-	return int(math.Round(max))
-}
-
-// cpuFreqMHz reads cpufreq sysfs: min/max are stable hardware limits (from
-// cpu0); current is the highest scaling_cur_freq across all cores — the "is it
-// boosting" figure. Values are kHz in sysfs. Returns zeros when cpufreq is
-// absent (e.g. some VMs).
-func cpuFreqMHz(root string) (min, max, cur int) {
-	min = readKHzAsMHz(filepath.Join(root, "cpu0/cpufreq/cpuinfo_min_freq"))
-	max = readKHzAsMHz(filepath.Join(root, "cpu0/cpufreq/cpuinfo_max_freq"))
-	cores, _ := filepath.Glob(filepath.Join(root, "cpu[0-9]*/cpufreq/scaling_cur_freq"))
-	for _, f := range cores {
-		if v := readKHzAsMHz(f); v > cur {
-			cur = v
-		}
-	}
-	return min, max, cur
-}
-
-func readKHzAsMHz(path string) int {
-	khz, err := strconv.Atoi(readTrim(path))
-	if err != nil {
-		return 0
-	}
-	return khz / 1000
-}
-
-// cpuModel extracts the processor model from /proc/cpuinfo. x86 uses "model
-// name"; many ARM boards use "Model" instead, so fall back to it.
-func cpuModel(cpuinfo string) string {
-	var fallback string
-	for line := range strings.SplitSeq(cpuinfo, "\n") {
-		k, v, ok := strings.Cut(line, ":")
-		if !ok {
-			continue
-		}
-		switch strings.TrimSpace(k) {
-		case "model name":
-			return strings.TrimSpace(v)
-		case "Model":
-			fallback = strings.TrimSpace(v)
-		}
-	}
-	return fallback
-}
-
-func memInfo() MemoryInfo {
-	data, _ := os.ReadFile("/proc/meminfo")
-	return parseMeminfo(data)
-}
-
-// parseMeminfo reads the kB values in /proc/meminfo and converts them to bytes.
-func parseMeminfo(data []byte) MemoryInfo {
-	kv := map[string]uint64{}
-	for line := range strings.SplitSeq(string(data), "\n") {
-		k, v, ok := strings.Cut(line, ":")
-		if !ok {
-			continue
-		}
-		fields := strings.Fields(v) // e.g. "16384000 kB"
-		if len(fields) == 0 {
-			continue
-		}
-		if n, err := strconv.ParseUint(fields[0], 10, 64); err == nil {
-			kv[k] = n * 1024 // values are in kB
-		}
-	}
-	return MemoryInfo{
-		TotalBytes:     kv["MemTotal"],
-		AvailableBytes: kv["MemAvailable"],
-		UsedBytes:      kv["MemTotal"] - kv["MemAvailable"],
-		SwapTotalBytes: kv["SwapTotal"],
-		SwapFreeBytes:  kv["SwapFree"],
-	}
-}
-
-func loadInfo() LoadInfo {
-	data, _ := os.ReadFile("/proc/loadavg")
-	l := parseLoadavg(string(data))
-	l.CPUUsage = cachedCPUUsage()
-	return l
-}
-
-// parseLoadavg reads the three load averages from /proc/loadavg.
-func parseLoadavg(loadavg string) LoadInfo {
-	f := strings.Fields(loadavg)
-	if len(f) < 3 {
-		return LoadInfo{}
-	}
-	at := func(i int) float64 { v, _ := strconv.ParseFloat(f[i], 64); return v }
-	return LoadInfo{Load1: at(0), Load5: at(1), Load15: at(2)}
-}
-
-// ---------------------------------------------------------------------------
-// Per-core CPU usage sampler
-// ---------------------------------------------------------------------------
-//
-// /proc/stat exposes cumulative jiffies per core:
-//
-//   cpuN user nice system idle iowait irq softirq steal guest guest_nice
-//
-// We sample every second, compute the delta, and derive:
-//
-//   usage% = (totalΔ − idleΔ) / totalΔ × 100
-//
-// The result is cached behind a RWMutex so the HTTP handler never blocks.
-
-var (
-	usageMu    sync.RWMutex
-	usageCache []CoreUsage
-)
-
-func cachedCPUUsage() []CoreUsage {
-	usageMu.RLock()
-	defer usageMu.RUnlock()
-	// Return a copy so callers can't mutate the cache.
-	if usageCache == nil {
-		return nil
-	}
-	out := make([]CoreUsage, len(usageCache))
-	copy(out, usageCache)
-	return out
-}
-
-// startCPUSampler launches a goroutine that samples /proc/stat once per second
-// for the lifetime of the process. Safe to call multiple times (only the first
-// call starts the goroutine).
-var samplerOnce sync.Once
-
-func startCPUSampler() {
-	samplerOnce.Do(func() {
-		go cpuSamplerLoop("/proc/stat", 1*time.Second)
-	})
-}
-
-func cpuSamplerLoop(statPath string, interval time.Duration) {
-	prev := readProcStat(statPath)
-	for {
-		time.Sleep(interval)
-		cur := readProcStat(statPath)
-		usage := computeUsage(prev, cur)
-		usageMu.Lock()
-		usageCache = usage
-		usageMu.Unlock()
-		prev = cur
-	}
-}
-
-// cpuCoreTicks holds the cumulative jiffies for one "cpuN" line.
-type cpuCoreTicks struct {
-	core  int
-	total uint64
-	idle  uint64
-}
-
-// readProcStat reads /proc/stat and returns per-core tick totals. The
-// aggregate "cpu" line (no digit suffix) is skipped.
-func readProcStat(path string) []cpuCoreTicks {
-	data, _ := os.ReadFile(path)
-	var cores []cpuCoreTicks
-	for line := range strings.SplitSeq(string(data), "\n") {
-		if !strings.HasPrefix(line, "cpu") {
-			continue
-		}
-		fields := strings.Fields(line)
-		if len(fields) < 5 {
-			continue
-		}
-		// Skip the aggregate "cpu" line; we only want "cpu0", "cpu1", …
-		name := fields[0]
-		if name == "cpu" {
-			continue
-		}
-		coreIdx, err := strconv.Atoi(strings.TrimPrefix(name, "cpu"))
-		if err != nil {
-			continue
-		}
-		// Fields: user(1) nice(2) system(3) idle(4) iowait(5) irq(6) softirq(7) steal(8) …
-		var total, idle uint64
-		for _, f := range fields[1:] {
-			v, _ := strconv.ParseUint(f, 10, 64)
-			total += v
-		}
-		// idle = idle + iowait (indices 4 and 5 in the original line).
-		if len(fields) > 5 {
-			v4, _ := strconv.ParseUint(fields[4], 10, 64)
-			v5, _ := strconv.ParseUint(fields[5], 10, 64)
-			idle = v4 + v5
-		} else {
-			v4, _ := strconv.ParseUint(fields[4], 10, 64)
-			idle = v4
-		}
-		cores = append(cores, cpuCoreTicks{core: coreIdx, total: total, idle: idle})
-	}
-	return cores
-}
-
-func computeUsage(prev, cur []cpuCoreTicks) []CoreUsage {
-	prevMap := make(map[int]cpuCoreTicks, len(prev))
-	for _, c := range prev {
-		prevMap[c.core] = c
-	}
-	usage := make([]CoreUsage, 0, len(cur))
-	for _, c := range cur {
-		p, ok := prevMap[c.core]
-		if !ok {
-			continue
-		}
-		dTotal := c.total - p.total
-		dIdle := c.idle - p.idle
-		var pct float64
-		if dTotal > 0 {
-			pct = float64(dTotal-dIdle) / float64(dTotal) * 100
-			// Round to one decimal.
-			pct = math.Round(pct*10) / 10
-		}
-		usage = append(usage, CoreUsage{Core: c.core, UsagePct: pct})
-	}
-	return usage
-}
-
 // uptimeAndBoot reads /proc/uptime (seconds since boot) and derives boot time.
 // On any read error it returns zero values rather than failing the request.
 func uptimeAndBoot() (int64, time.Time) {
@@ -490,163 +78,3 @@ func uptimeAndBoot() (int64, time.Time) {
 	boot := time.Now().Add(-time.Duration(secs * float64(time.Second))).UTC()
 	return int64(secs), boot
 }
-
-func diskInfo() []DiskInfo {
-	entries, err := mounts.Proc()
-	if err != nil {
-		return nil
-	}
-	disks := []DiskInfo{}
-	seen := map[string]bool{}
-	for _, e := range entries {
-		// ponytail: filter by fstype, not device path. LXC/Docker containers
-		// expose their rootfs as a ZFS dataset name, an overlayfs, or a bind
-		// path — never /dev/* — so a "must start with /dev/" check silently
-		// returned no disks on those hosts. statfs + non-zero blocks already
-		// excludes mounts that aren't real storage.
-		if pseudoFS[e.FSType] || seen[e.Mountpoint] {
-			continue
-		}
-		var st syscall.Statfs_t
-		if syscall.Statfs(e.Mountpoint, &st) != nil || st.Blocks == 0 {
-			continue
-		}
-		seen[e.Mountpoint] = true
-		bs := uint64(st.Bsize)
-		disks = append(disks, DiskInfo{
-			Mountpoint: e.Mountpoint,
-			Filesystem: e.Device,
-			FSType:     e.FSType,
-			TotalBytes: st.Blocks * bs,
-			FreeBytes:  st.Bavail * bs,
-			UsedBytes:  (st.Blocks - st.Bfree) * bs,
-		})
-	}
-	return disks
-}
-
-// pseudoFS lists kernel-virtual filesystems that show up in /proc/mounts but
-// aren't user-facing storage. squashfs covers snap loop mounts; fuse.lxcfs is
-// LXC's per-container /proc/* shim. Anything not on this list and statfs-able
-// with non-zero blocks is treated as real storage — covers ext*, btrfs, xfs,
-// zfs, nfs, cifs, overlay, and the bind-mount cases inside Proxmox LXC.
-var pseudoFS = map[string]bool{
-	"autofs":        true,
-	"binfmt_misc":   true,
-	"bpf":           true,
-	"cgroup":        true,
-	"cgroup2":       true,
-	"configfs":      true,
-	"debugfs":       true,
-	"devpts":        true,
-	"devtmpfs":      true,
-	"fuse.gvfsd-fuse": true,
-	"fuse.lxcfs":    true,
-	"fusectl":       true,
-	"hugetlbfs":     true,
-	"mqueue":        true,
-	"nsfs":          true,
-	"overlay":       true,
-	"proc":          true,
-	"pstore":        true,
-	"ramfs":         true,
-	"rpc_pipefs":    true,
-	"securityfs":    true,
-	"squashfs":      true,
-	"sysfs":         true,
-	"tmpfs":         true,
-	"tracefs":       true,
-}
-
-func netInfo() []NetInterface {
-	ifaces, err := net.Interfaces()
-	if err != nil {
-		return nil
-	}
-	out := []NetInterface{}
-	for _, ifi := range ifaces {
-		addrs, _ := ifi.Addrs()
-		strs := []string{}
-		for _, a := range addrs {
-			strs = append(strs, a.String())
-		}
-		out = append(out, NetInterface{
-			Name:      ifi.Name,
-			MAC:       ifi.HardwareAddr.String(),
-			Up:        ifi.Flags&net.FlagUp != 0,
-			Addresses: strs,
-		})
-	}
-	return out
-}
-
-func tempInfo() []Temperature {
-	if t := readHwmonTemps("/sys/class/hwmon"); len(t) > 0 {
-		return t
-	}
-	// ponytail: stock Ubuntu server has no coretemp/k10temp loaded, so hwmon
-	// is empty; thermal_zone exposes ACPI sensors (coarser, no chip name).
-	return readThermalZones("/sys/class/thermal")
-}
-
-// readThermalZones reads /sys/class/thermal/thermal_zone*/temp as a fallback
-// for hosts without hwmon chip drivers. "type" names the zone (e.g. acpitz,
-// x86_pkg_temp); used as both chip and label.
-func readThermalZones(root string) []Temperature {
-	zones, _ := filepath.Glob(filepath.Join(root, "thermal_zone*"))
-	temps := []Temperature{}
-	for _, dir := range zones {
-		milli, err := strconv.Atoi(readTrim(filepath.Join(dir, "temp")))
-		if err != nil {
-			continue
-		}
-		c := float64(milli) / 1000
-		if c <= 0 || c >= 150 {
-			continue
-		}
-		name := readTrim(filepath.Join(dir, "type"))
-		if name == "" {
-			name = filepath.Base(dir)
-		}
-		temps = append(temps, Temperature{Chip: name, Label: name, Celsius: c})
-	}
-	return temps
-}
-
-// readHwmonTemps walks /sys/class/hwmon, which (unlike /sys/class/thermal, that
-// only exposes generic ACPI zones like "acpitz") names each chip — so callers
-// can split CPU (k10temp/coretemp) from GPU (amdgpu/nvidia) from disk (nvme).
-// Each tempN_input may carry a tempN_label; when absent we fall back to the
-// chip name. Best-effort: unreadable, empty, or implausible sensors are skipped.
-func readHwmonTemps(root string) []Temperature {
-	chips, _ := filepath.Glob(filepath.Join(root, "hwmon*"))
-	temps := []Temperature{}
-	for _, dir := range chips {
-		chip := readTrim(filepath.Join(dir, "name"))
-		inputs, _ := filepath.Glob(filepath.Join(dir, "temp*_input"))
-		for _, in := range inputs {
-			milli, err := strconv.Atoi(readTrim(in))
-			if err != nil {
-				continue
-			}
-			c := float64(milli) / 1000
-			// Disabled/placeholder sensors report absurd values (e.g. -0.15 or
-			// 179.8 °C). Drop anything outside a plausible band.
-			if c <= 0 || c >= 150 {
-				continue
-			}
-			label := readTrim(strings.TrimSuffix(in, "_input") + "_label")
-			if label == "" {
-				label = chip
-			}
-			temps = append(temps, Temperature{Chip: chip, Label: label, Celsius: c})
-		}
-	}
-	return temps
-}
-
-// readTrim reads a sysfs file and trims it; a missing file yields "".
-func readTrim(path string) string {
-	b, _ := os.ReadFile(path)
-	return strings.TrimSpace(string(b))
-}

internal/modules/system/info_test.go

@@ -6,6 +6,106 @@ import (
 	"testing"
 )
 
+func TestReadGPUsFromSysfs(t *testing.T) {
+	root := t.TempDir()
+
+	// card0 — AMD GPU with VRAM and utilization files
+	pciDev := filepath.Join(root, "devices/pci0000:00/0000:00:02.0")
+	mkdirAll(t, pciDev)
+	write(t, pciDev, ".", "vendor", "0x1002")
+	write(t, pciDev, ".", "device", "0x7480")
+	write(t, pciDev, ".", "mem_info_vram_total", "8573157376")
+	write(t, pciDev, ".", "mem_info_vram_used", "27267072")
+	write(t, pciDev, ".", "gpu_busy_percent", "23")
+	write(t, pciDev, ".", "mem_busy_percent", "15")
+
+	driverDir := filepath.Join(root, "bus/pci/drivers/amdgpu")
+	mkdirAll(t, driverDir)
+	mustSymlink(t, driverDir, filepath.Join(pciDev, "driver"))
+
+	cardTarget := filepath.Join(pciDev, "drm", "card0")
+	mkdirAll(t, cardTarget)
+	mustSymlink(t, pciDev, filepath.Join(cardTarget, "device"))
+	mustSymlink(t, cardTarget, filepath.Join(root, "card0"))
+
+	// Distractors
+	write(t, root, ".", "card0-HDMI-1", "distract")
+	write(t, root, ".", "renderD128", "distract")
+
+	gpus := readGPUsFromSysfs(root)
+	if len(gpus) != 1 {
+		t.Fatalf("want 1 GPU, got %d: %+v", len(gpus), gpus)
+	}
+	if gpus[0].Vendor != "1002" {
+		t.Errorf("vendor = %q, want 1002", gpus[0].Vendor)
+	}
+	if gpus[0].DeviceID != "7480" {
+		t.Errorf("device_id = %q, want 7480", gpus[0].DeviceID)
+	}
+	if gpus[0].Driver != "amdgpu" {
+		t.Errorf("driver = %q, want amdgpu", gpus[0].Driver)
+	}
+	if gpus[0].MemoryTotalBytes != 8573157376 {
+		t.Errorf("MemoryTotalBytes = %d, want 8573157376", gpus[0].MemoryTotalBytes)
+	}
+	if gpus[0].MemoryUsedBytes != 27267072 {
+		t.Errorf("MemoryUsedBytes = %d, want 27267072", gpus[0].MemoryUsedBytes)
+	}
+	if gpus[0].UtilizationPct != 23.0 {
+		t.Errorf("UtilizationPct = %f, want 23.0", gpus[0].UtilizationPct)
+	}
+	if gpus[0].MemUtilizationPct != 15.0 {
+		t.Errorf("MemUtilizationPct = %f, want 15.0", gpus[0].MemUtilizationPct)
+	}
+}
+
+func TestReadGPUsFromSysfsNoEnrichment(t *testing.T) {
+	root := t.TempDir()
+
+	// i915 GPU with no VRAM or utilization files
+	pciDev := filepath.Join(root, "devices/pci0000:00/0000:00:02.0")
+	mkdirAll(t, pciDev)
+	write(t, pciDev, ".", "vendor", "0x8086")
+	write(t, pciDev, ".", "device", "0x46a6")
+
+	driverDir := filepath.Join(root, "bus/pci/drivers/i915")
+	mkdirAll(t, driverDir)
+	mustSymlink(t, driverDir, filepath.Join(pciDev, "driver"))
+
+	cardTarget := filepath.Join(pciDev, "drm", "card0")
+	mkdirAll(t, cardTarget)
+	mustSymlink(t, pciDev, filepath.Join(cardTarget, "device"))
+	mustSymlink(t, cardTarget, filepath.Join(root, "card0"))
+
+	gpus := readGPUsFromSysfs(root)
+	if len(gpus) != 1 {
+		t.Fatalf("want 1 GPU, got %d", len(gpus))
+	}
+	if gpus[0].MemoryTotalBytes != 0 || gpus[0].MemoryUsedBytes != 0 {
+		t.Errorf("expected 0 VRAM for i915, got total=%d used=%d", gpus[0].MemoryTotalBytes, gpus[0].MemoryUsedBytes)
+	}
+	if gpus[0].UtilizationPct != 0 || gpus[0].MemUtilizationPct != 0 {
+		t.Errorf("expected 0 utilization for i915, got gpu=%f mem=%f", gpus[0].UtilizationPct, gpus[0].MemUtilizationPct)
+	}
+}
+
+func TestReadGPUsFromSysfsMissingDir(t *testing.T) {
+	gpus := readGPUsFromSysfs("/nonexistent/drm")
+	if gpus != nil {
+		t.Errorf("expected nil, got %+v", gpus)
+	}
+}
+
+func TestReadGPUsFromSysfsSkipsNonGPU(t *testing.T) {
+	root := t.TempDir()
+	write(t, root, ".", "renderD128", "x")
+	write(t, root, ".", "card0-HDMI-1", "x")
+	gpus := readGPUsFromSysfs(root)
+	if len(gpus) != 0 {
+		t.Errorf("expected 0 GPUs, got %d", len(gpus))
+	}
+}
+
 func TestReadHwmonTemps(t *testing.T) {
 	root := t.TempDir()
 	// k10temp: CPU, labelled Tctl.
@@ -33,6 +133,20 @@ func TestReadHwmonTemps(t *testing.T) {
 	}
 }
 
+func mkdirAll(t *testing.T, path string) {
+	t.Helper()
+	if err := os.MkdirAll(path, 0o755); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func mustSymlink(t *testing.T, target, link string) {
+	t.Helper()
+	if err := os.Symlink(target, link); err != nil {
+		t.Fatal(err)
+	}
+}
+
 func write(t *testing.T, root, chip, file, val string) {
 	t.Helper()
 	dir := filepath.Join(root, chip)

internal/modules/system/load.go

@@ -0,0 +1,37 @@
+package system
+
+import (
+	"os"
+	"strconv"
+	"strings"
+)
+
+// CoreUsage holds the usage percentage for a single logical core, computed as
+// the delta of non-idle ticks over total ticks between two /proc/stat reads.
+type CoreUsage struct {
+	Core      int     `json:"core" example:"0" doc:"Logical core index"`
+	UsagePct  float64 `json:"usage_pct" example:"23.4" doc:"Usage percentage (0–100)"`
+}
+
+type LoadInfo struct {
+	Load1    float64     `json:"load1" example:"0.42"`
+	Load5    float64     `json:"load5" example:"0.55"`
+	Load15   float64     `json:"load15" example:"0.61"`
+	CPUUsage []CoreUsage `json:"cpu_usage" doc:"Per-core CPU usage percentage (sampled over ~1 s); empty until the first sample completes"`
+}
+
+func loadInfo(sampler *Sampler) LoadInfo {
+	data, _ := os.ReadFile("/proc/loadavg")
+	l := parseLoadavg(string(data))
+	l.CPUUsage = sampler.Snapshot()
+	return l
+}
+
+func parseLoadavg(loadavg string) LoadInfo {
+	f := strings.Fields(loadavg)
+	if len(f) < 3 {
+		return LoadInfo{}
+	}
+	at := func(i int) float64 { v, _ := strconv.ParseFloat(f[i], 64); return v }
+	return LoadInfo{Load1: at(0), Load5: at(1), Load15: at(2)}
+}

internal/modules/system/memory.go

@@ -0,0 +1,44 @@
+package system
+
+import (
+	"os"
+	"strconv"
+	"strings"
+)
+
+type MemoryInfo struct {
+	TotalBytes     uint64 `json:"total_bytes" example:"16384000000"`
+	AvailableBytes uint64 `json:"available_bytes" example:"8192000000" doc:"Memory available for new allocations without swapping"`
+	UsedBytes      uint64 `json:"used_bytes" example:"8192000000" doc:"total - available"`
+	SwapTotalBytes uint64 `json:"swap_total_bytes" example:"8589934592"`
+	SwapFreeBytes  uint64 `json:"swap_free_bytes" example:"8589934592"`
+}
+
+func memInfo() MemoryInfo {
+	data, _ := os.ReadFile("/proc/meminfo")
+	return parseMeminfo(data)
+}
+
+func parseMeminfo(data []byte) MemoryInfo {
+	kv := map[string]uint64{}
+	for line := range strings.SplitSeq(string(data), "\n") {
+		k, v, ok := strings.Cut(line, ":")
+		if !ok {
+			continue
+		}
+		fields := strings.Fields(v)
+		if len(fields) == 0 {
+			continue
+		}
+		if n, err := strconv.ParseUint(fields[0], 10, 64); err == nil {
+			kv[k] = n * 1024
+		}
+	}
+	return MemoryInfo{
+		TotalBytes:     kv["MemTotal"],
+		AvailableBytes: kv["MemAvailable"],
+		UsedBytes:      kv["MemTotal"] - kv["MemAvailable"],
+		SwapTotalBytes: kv["SwapTotal"],
+		SwapFreeBytes:  kv["SwapFree"],
+	}
+}

internal/modules/system/module.go

@@ -1,6 +1,9 @@
 package system
 
 import (
+	"context"
+	"time"
+
 	"nadir/internal/rbac"
 
 	"github.com/danielgtaylor/huma/v2"
@@ -8,9 +11,15 @@ import (
 
 const ModuleID = "system"
 
-type Module struct{}
+type Module struct {
+	sampler *Sampler
+}
 
-func New() *Module { return &Module{} }
+func New() *Module {
+	return &Module{
+		sampler: NewSampler("/proc/stat", 1*time.Second),
+	}
+}
 
 func (m *Module) ID() string   { return ModuleID }
 
@@ -19,7 +28,8 @@ func (m *Module) Permissions() []rbac.Permission {
 }
 
 func (m *Module) Register(api huma.API) {
-	registerInfo(api)
+	m.sampler.Start(context.Background())
+	registerInfo(api, m.sampler)
 	registerHostname(api)
 	registerTimedate(api)
 	registerLocale(api)

internal/modules/system/network.go

@@ -0,0 +1,32 @@
+package system
+
+import "net"
+
+type NetInterface struct {
+	Name      string   `json:"name" example:"eth0"`
+	MAC       string   `json:"mac" example:"aa:bb:cc:dd:ee:ff"`
+	Up        bool     `json:"up" doc:"Interface is administratively up"`
+	Addresses []string `json:"addresses" doc:"Assigned addresses in CIDR notation"`
+}
+
+func netInfo() []NetInterface {
+	ifaces, err := net.Interfaces()
+	if err != nil {
+		return nil
+	}
+	out := []NetInterface{}
+	for _, ifi := range ifaces {
+		addrs, _ := ifi.Addrs()
+		strs := []string{}
+		for _, a := range addrs {
+			strs = append(strs, a.String())
+		}
+		out = append(out, NetInterface{
+			Name:      ifi.Name,
+			MAC:       ifi.HardwareAddr.String(),
+			Up:        ifi.Flags&net.FlagUp != 0,
+			Addresses: strs,
+		})
+	}
+	return out
+}

internal/modules/system/os.go

@@ -0,0 +1,42 @@
+package system
+
+import (
+	"os"
+	"strings"
+
+	"nadir/internal/oscmd"
+)
+
+type OSInfo struct {
+	PrettyName   string `json:"pretty_name" example:"Fedora Linux 44 (Workstation Edition)" doc:"Distro name from /etc/os-release PRETTY_NAME"`
+	Kernel       string `json:"kernel" example:"7.0.12-201.fc44.x86_64" doc:"Running kernel release (uname -r)"`
+	Architecture string `json:"architecture" example:"x86_64" doc:"Machine hardware architecture (uname -m)"`
+	Hostname     string `json:"hostname" example:"server01" doc:"System hostname"`
+}
+
+func osInfo() OSInfo {
+	host, _ := os.Hostname()
+	return OSInfo{
+		PrettyName:   osReleasePretty(),
+		Kernel:       firstLine(oscmd.Run("uname", "-r")),
+		Architecture: firstLine(oscmd.Run("uname", "-m")),
+		Hostname:     host,
+	}
+}
+
+// firstLine discards a command error and returns its (already trimmed) output,
+// used where a missing value is acceptable.
+func firstLine(out string, _ error) string { return out }
+
+func osReleasePretty() string {
+	data, err := os.ReadFile("/etc/os-release")
+	if err != nil {
+		return ""
+	}
+	for line := range strings.SplitSeq(string(data), "\n") {
+		if v, ok := strings.CutPrefix(line, "PRETTY_NAME="); ok {
+			return strings.Trim(v, `"`)
+		}
+	}
+	return ""
+}

internal/modules/system/power_test.go

@@ -3,16 +3,34 @@ package system
 import "testing"
 
 func TestWhenRe(t *testing.T) {
-	valid := []string{"now", "+0", "+5", "+120", "0:00", "9:30", "23:59", "07:05"}
-	for _, w := range valid {
-		if !whenRe.MatchString(w) {
-			t.Errorf("whenRe.MatchString(%q) = false, want true", w)
-		}
-	}
-	invalid := []string{"", "-r", "-h", "--help", "24:00", "9:60", "+5; reboot", "now ", "5", "1:2"}
-	for _, w := range invalid {
-		if whenRe.MatchString(w) {
-			t.Errorf("whenRe.MatchString(%q) = true, want false", w)
-		}
+	for _, tt := range []struct {
+		name  string
+		value string
+		want  bool
+	}{
+		{name: "now", value: "now", want: true},
+		{name: "plus zero", value: "+0", want: true},
+		{name: "plus five", value: "+5", want: true},
+		{name: "plus 120", value: "+120", want: true},
+		{name: "0:00", value: "0:00", want: true},
+		{name: "9:30", value: "9:30", want: true},
+		{name: "23:59", value: "23:59", want: true},
+		{name: "07:05", value: "07:05", want: true},
+		{name: "empty", value: "", want: false},
+		{name: "flag r", value: "-r", want: false},
+		{name: "flag h", value: "-h", want: false},
+		{name: "help", value: "--help", want: false},
+		{name: "24:00", value: "24:00", want: false},
+		{name: "9:60", value: "9:60", want: false},
+		{name: "injected command", value: "+5; reboot", want: false},
+		{name: "trailing space", value: "now ", want: false},
+		{name: "just digit", value: "5", want: false},
+		{name: "single colon", value: "1:2", want: false},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := whenRe.MatchString(tt.value); got != tt.want {
+				t.Errorf("whenRe.MatchString(%q) = %v, want %v", tt.value, got, tt.want)
+			}
+		})
 	}
 }

internal/modules/system/system_handler_test.go

@@ -22,7 +22,7 @@ func TestSystemHandlers(t *testing.T) {
 	registerTimedate(api)
 	registerLocale(api)
 	registerPower(api)
-	registerInfo(api)
+	registerInfo(api, NewSampler("/proc/stat", 0))
 
 	// Mock uname for GET /api/system/info
 	oscmd.SetMock("uname", func(args []string) oscmd.MockCommand {
@@ -34,6 +34,14 @@ func TestSystemHandlers(t *testing.T) {
 		}
 		return oscmd.MockCommand{ExitCode: 1}
 	})
+	// Mock lspci to prevent real calls in case the test host has GPUs.
+	oscmd.SetMock("lspci", func(args []string) oscmd.MockCommand {
+		return oscmd.MockCommand{ExitCode: 1}
+	})
+	// Mock nvidia-smi: return failure so enrichment is a no-op.
+	oscmd.SetMock("nvidia-smi", func(args []string) oscmd.MockCommand {
+		return oscmd.MockCommand{ExitCode: 1}
+	})
 	defer oscmd.ClearMocks()
 
 	// 1. Test GET /api/system/info

internal/modules/system/temperature.go

@@ -0,0 +1,73 @@
+package system
+
+import (
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+type Temperature struct {
+	Chip    string  `json:"chip" example:"k10temp" doc:"hwmon chip name; identifies the source (k10temp/coretemp=CPU, amdgpu/nvidia=GPU, nvme=disk)"`
+	Label   string  `json:"label" example:"Tctl" doc:"Per-sensor label, or the chip name when the sensor is unlabelled"`
+	Celsius float64 `json:"celsius" example:"47.5"`
+}
+
+func tempInfo() []Temperature {
+	if t := readHwmonTemps("/sys/class/hwmon"); len(t) > 0 {
+		return t
+	}
+	return readThermalZones("/sys/class/thermal")
+}
+
+func readThermalZones(root string) []Temperature {
+	zones, _ := filepath.Glob(filepath.Join(root, "thermal_zone*"))
+	temps := []Temperature{}
+	for _, dir := range zones {
+		milli, err := strconv.Atoi(readTrim(filepath.Join(dir, "temp")))
+		if err != nil {
+			continue
+		}
+		c := float64(milli) / 1000
+		if c <= 0 || c >= 150 {
+			continue
+		}
+		name := readTrim(filepath.Join(dir, "type"))
+		if name == "" {
+			name = filepath.Base(dir)
+		}
+		temps = append(temps, Temperature{Chip: name, Label: name, Celsius: c})
+	}
+	return temps
+}
+
+func readHwmonTemps(root string) []Temperature {
+	chips, _ := filepath.Glob(filepath.Join(root, "hwmon*"))
+	temps := []Temperature{}
+	for _, dir := range chips {
+		chip := readTrim(filepath.Join(dir, "name"))
+		inputs, _ := filepath.Glob(filepath.Join(dir, "temp*_input"))
+		for _, in := range inputs {
+			milli, err := strconv.Atoi(readTrim(in))
+			if err != nil {
+				continue
+			}
+			c := float64(milli) / 1000
+			if c <= 0 || c >= 150 {
+				continue
+			}
+			label := readTrim(strings.TrimSuffix(in, "_input") + "_label")
+			if label == "" {
+				label = chip
+			}
+			temps = append(temps, Temperature{Chip: chip, Label: label, Celsius: c})
+		}
+	}
+	return temps
+}
+
+// readTrim reads a sysfs file and trims it; a missing file yields "".
+func readTrim(path string) string {
+	b, _ := os.ReadFile(path)
+	return strings.TrimSpace(string(b))
+}

internal/modules/terminal/terminal.go

@@ -1,209 +0,0 @@
-package terminal
-
-import (
-	"context"
-	"encoding/json"
-	"net/http"
-	"os/exec"
-	"strings"
-	"sync/atomic"
-	"time"
-
-	"nadir/internal/auth"
-	"nadir/internal/module"
-	"nadir/internal/rbac"
-
-	"github.com/coder/websocket"
-	"github.com/creack/pty"
-	"github.com/danielgtaylor/huma/v2"
-	"github.com/danielgtaylor/huma/v2/adapters/humago"
-)
-
-// tagTerminal is the OpenAPI tag for this module (registered in server.go),
-// keeping tags 1:1 with modules per the project convention.
-const tagTerminal = "Terminal"
-
-const (
-	// maxTerminals caps concurrent shells so a buggy frontend or careless admin
-	// can't pile up PTYs (guideline: limit everything). Raise if it's ever a real
-	// limit in practice.
-	maxTerminals = 10
-	// idleTimeout closes a session after this long with no I/O in either
-	// direction, reclaiming abandoned shells.
-	idleTimeout = 15 * time.Minute
-)
-
-// terminalSem is the concurrency limiter; a slot is held for the life of a session.
-var terminalSem = make(chan struct{}, maxTerminals)
-
-type terminalModule struct {
-	sessions *auth.SessionStore
-}
-
-// New creates a new Terminal module that allows interactive shell access.
-func New(sessions *auth.SessionStore) module.Module {
-	return &terminalModule{sessions: sessions}
-}
-
-func (m *terminalModule) ID() string   { return "terminal" }
-
-func (m *terminalModule) Permissions() []rbac.Permission {
-	return []rbac.Permission{rbac.Root}
-}
-
-type TerminalInput struct {
-	Ctx huma.Context `json:"-"`
-}
-
-// Resolve extracts the huma.Context into the input struct.
-func (i *TerminalInput) Resolve(ctx huma.Context) []error {
-	i.Ctx = ctx
-	return nil
-}
-
-type resizeMessage struct {
-	Cols uint16 `json:"cols"`
-	Rows uint16 `json:"rows"`
-}
-
-func (m *terminalModule) Register(api huma.API) {
-	huma.Register(api, huma.Operation{
-		OperationID: "terminal-connect",
-		Method:      "GET",
-		Path:        "/api/terminal",
-		Summary:     "Connect to an interactive terminal",
-		Description: "Upgrades the connection to a WebSocket and spawns a PTY shell as the logged-in user. Send JSON `{cols, rows}` text messages to resize, and raw binary/text messages for stdin. This is a raw WebSocket endpoint — it cannot be exercised from the API docs \"Try it\" panel; use a WebSocket client.",
-		Tags:        []string{tagTerminal},
-		Metadata:    map[string]any{"module": m.ID(), "permission": string(rbac.Root)},
-		Errors:      []int{401, 403, 426, 500},
-	}, func(ctx context.Context, in *TerminalInput) (*struct{}, error) {
-		// The RBAC middleware already authenticated this request and enforced the
-		// "root" permission before we got here. We re-read the session only to get
-		// the username for `su`; the 401 below is the fallback for when the module
-		// is mounted without the middleware (e.g. in unit tests).
-		cookie, err := huma.ReadCookie(in.Ctx, "nadir_session_id")
-		if err != nil || cookie == nil {
-			return nil, huma.Error401Unauthorized("unauthorized")
-		}
-
-		sess, ok := m.sessions.GetByToken(cookie.Value)
-		if !ok {
-			return nil, huma.Error401Unauthorized("unauthorized")
-		}
-
-		req, res := humago.Unwrap(in.Ctx)
-		if req == nil || res == nil {
-			return nil, huma.Error500InternalServerError("missing http context")
-		}
-
-		// Reject plain GETs (e.g. the docs "Try it" button) with a clear 426 rather
-		// than letting websocket.Accept emit a raw protocol-violation error.
-		if !strings.EqualFold(req.Header.Get("Upgrade"), "websocket") {
-			return nil, huma.NewError(http.StatusUpgradeRequired,
-				"this endpoint requires a WebSocket connection; connect with a WebSocket client")
-		}
-
-		// InsecureSkipVerify is deliberately NOT set: coder/websocket then enforces
-		// that the Origin host matches the request Host, rejecting cross-site upgrade
-		// attempts. Defense-in-depth on top of the SameSite=Strict session cookie —
-		// important because this endpoint hands out an interactive shell.
-		conn, err := websocket.Accept(res, req, nil)
-		if err != nil {
-			// websocket.Accept already wrote the error response (e.g. 403 on an
-			// Origin mismatch). Just stop; writing again would corrupt the response.
-			return nil, nil
-		}
-		defer conn.CloseNow()
-
-		// Bound concurrent shells: take a slot or reject (don't pile up PTYs).
-		select {
-		case terminalSem <- struct{}{}:
-			defer func() { <-terminalSem }()
-		default:
-			conn.Close(websocket.StatusTryAgainLater, "too many terminal sessions")
-			return nil, nil
-		}
-
-		// Launch the user's login shell via su.
-		// "su - <username>" ensures we get their actual environment and shell.
-		cmd := exec.CommandContext(req.Context(), "su", "-", "--", sess.Username)
-
-		// Start the command with a PTY.
-		ptmx, err := pty.Start(cmd)
-		if err != nil {
-			conn.Close(websocket.StatusInternalError, "failed to start pty")
-			return nil, nil
-		}
-		defer ptmx.Close()
-
-		// lastActive is bumped by both pumps; the watchdog uses it to close idle
-		// sessions. Output activity (e.g. `top`) counts, so it isn't killed.
-		var lastActive atomic.Int64
-		lastActive.Store(time.Now().UnixNano())
-		go func() {
-			tick := time.NewTicker(idleTimeout / 4)
-			defer tick.Stop()
-			for {
-				select {
-				case <-req.Context().Done():
-					return
-				case <-tick.C:
-					if time.Since(time.Unix(0, lastActive.Load())) > idleTimeout {
-						conn.Close(websocket.StatusGoingAway, "idle timeout")
-						return
-					}
-				}
-			}
-		}()
-
-		// Pump stdout/stderr from PTY to WebSocket.
-		go func() {
-			buf := make([]byte, 8192)
-			for {
-				n, err := ptmx.Read(buf)
-				if err != nil {
-					break
-				}
-				lastActive.Store(time.Now().UnixNano())
-				// We write PTY output as binary messages. The frontend (e.g., xterm.js)
-				// can handle UTF-8 binary or text transparently.
-				err = conn.Write(req.Context(), websocket.MessageBinary, buf[:n])
-				if err != nil {
-					break
-				}
-			}
-			conn.Close(websocket.StatusNormalClosure, "")
-		}()
-
-		// Pump stdin and resize commands from WebSocket to PTY.
-		for {
-			typ, b, err := conn.Read(req.Context())
-			if err != nil {
-				break
-			}
-			lastActive.Store(time.Now().UnixNano())
-
-			if typ == websocket.MessageText {
-				var resize resizeMessage
-				if err := json.Unmarshal(b, &resize); err == nil && resize.Cols > 0 && resize.Rows > 0 {
-					// Handle resize
-					_ = pty.Setsize(ptmx, &pty.Winsize{
-						Cols: resize.Cols,
-						Rows: resize.Rows,
-					})
-					continue
-				}
-			}
-
-			// If not a valid resize message, or if it's MessageBinary, pass to PTY stdin.
-			_, _ = ptmx.Write(b)
-		}
-
-		// The read loop has ended (client gone or PTY closed). Tear down the shell
-		// and reap it: closing the PTY sends EOF, Kill covers shells that ignore it.
-		_ = ptmx.Close()
-		_ = cmd.Process.Kill()
-		_ = cmd.Wait()
-		return nil, nil
-	})
-}

internal/modules/terminal/terminal_test.go

@@ -1,124 +0,0 @@
-package terminal
-
-import (
-	"context"
-	"net/http"
-	"net/http/httptest"
-	"strings"
-	"testing"
-	"time"
-
-	"nadir/internal/auth"
-
-	"github.com/coder/websocket"
-	"github.com/danielgtaylor/huma/v2"
-	"github.com/danielgtaylor/huma/v2/adapters/humago"
-)
-
-func TestTerminalConnectUnauthorized(t *testing.T) {
-	sessions, err := auth.NewSessionStore("file::memory:?cache=shared")
-	if err != nil {
-		t.Fatalf("session db: %v", err)
-	}
-
-	mux := http.NewServeMux()
-	api := humago.New(mux, huma.DefaultConfig("Test", "1.0.0"))
-	mod := New(sessions)
-	mod.Register(api)
-
-	srv := httptest.NewServer(mux)
-	defer srv.Close()
-
-	wsURL := strings.Replace(srv.URL, "http://", "ws://", 1) + "/api/terminal"
-
-	// Try without cookie
-	ctx, cancel := context.WithTimeout(t.Context(), 2*time.Second)
-	defer cancel()
-
-	_, resp, err := websocket.Dial(ctx, wsURL, nil)
-	if err == nil {
-		t.Fatal("expected error, got success")
-	}
-	if resp != nil && resp.StatusCode != http.StatusUnauthorized {
-		t.Errorf("expected 401, got %d", resp.StatusCode)
-	}
-}
-
-func TestTerminalConnectPlainGET(t *testing.T) {
-	// An authenticated but non-WebSocket GET (e.g. the docs "Try it" button) must
-	// get a clean 426 Upgrade Required, not a raw websocket protocol error.
-	sessions, err := auth.NewSessionStore("file::memory:?cache=shared")
-	if err != nil {
-		t.Fatalf("session db: %v", err)
-	}
-	token, err := sessions.Create("root")
-	if err != nil {
-		t.Fatalf("create session: %v", err)
-	}
-
-	mux := http.NewServeMux()
-	api := humago.New(mux, huma.DefaultConfig("Test", "1.0.0"))
-	New(sessions).Register(api)
-
-	srv := httptest.NewServer(mux)
-	defer srv.Close()
-
-	req, _ := http.NewRequest(http.MethodGet, srv.URL+"/api/terminal", nil)
-	req.Header.Set("Cookie", "nadir_session_id="+token)
-	resp, err := http.DefaultClient.Do(req)
-	if err != nil {
-		t.Fatalf("GET failed: %v", err)
-	}
-	defer resp.Body.Close()
-	if resp.StatusCode != http.StatusUpgradeRequired {
-		t.Errorf("expected 426, got %d", resp.StatusCode)
-	}
-}
-
-func TestTerminalConnectAuthorized(t *testing.T) {
-	// Root or specific system configs might cause PTY or su to fail if run in constrained environments.
-	// But we expect the websocket upgrade to succeed and then maybe close with an error if PTY fails.
-	sessions, err := auth.NewSessionStore("file::memory:?cache=shared")
-	if err != nil {
-		t.Fatalf("session db: %v", err)
-	}
-
-	token, err := sessions.Create("root")
-	if err != nil {
-		t.Fatalf("create session: %v", err)
-	}
-
-	mux := http.NewServeMux()
-	api := humago.New(mux, huma.DefaultConfig("Test", "1.0.0"))
-	mod := New(sessions)
-	mod.Register(api)
-
-	srv := httptest.NewServer(mux)
-	defer srv.Close()
-
-	wsURL := strings.Replace(srv.URL, "http://", "ws://", 1) + "/api/terminal"
-
-	ctx, cancel := context.WithTimeout(t.Context(), 2*time.Second)
-	defer cancel()
-
-	opts := &websocket.DialOptions{
-		HTTPHeader: http.Header{},
-	}
-	opts.HTTPHeader.Set("Cookie", "nadir_session_id="+token)
-
-	conn, resp, err := websocket.Dial(ctx, wsURL, opts)
-	if err != nil {
-		// Depending on the test environment, "su" or "pty" might fail, but
-		// the websocket upgrade itself should succeed before it drops.
-		// If it fails to upgrade, that's a real error.
-		t.Fatalf("dial failed: %v (status %d)", err, resp.StatusCode)
-	}
-	defer conn.CloseNow()
-
-	// The connection was upgraded successfully.
-	// If PTY allocation failed or su failed, the server might close the connection immediately.
-	// We just verify the upgrade succeeded.
-	if resp.StatusCode != http.StatusSwitchingProtocols {
-		t.Errorf("expected 101, got %d", resp.StatusCode)
-	}
-}

internal/modules/users/module.go

@@ -8,9 +8,17 @@ import (
 
 const ModuleID = "users"
 
-type Module struct{}
+// sessionStore is the subset of SessionStore that password changes need:
+// invalidate all existing sessions for a user whose password just changed.
+type sessionStore interface {
+	DeleteByUsername(username string) error
+}
 
-func New() *Module { return &Module{} }
+type Module struct {
+	sessions sessionStore
+}
+
+func New(sessions sessionStore) *Module { return &Module{sessions: sessions} }
 
 func (m *Module) ID() string   { return ModuleID }
 
@@ -21,7 +29,7 @@ func (m *Module) Permissions() []rbac.Permission {
 }
 
 func (m *Module) Register(api huma.API) {
-	registerUsers(api)
+	registerUsers(api, m.sessions)
 }
 
 func op(permission string) map[string]any {

internal/modules/users/users.go

@@ -2,6 +2,7 @@ package users
 
 import (
 	"context"
+	"log"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -91,7 +92,7 @@ type UserGroupsOutput struct {
 	}
 }
 
-func registerUsers(api huma.API) {
+func registerUsers(api huma.API, sessions sessionStore) {
 	huma.Register(api, huma.Operation{
 		OperationID: "users-list",
 		Method:      "GET",
@@ -105,7 +106,7 @@ func registerUsers(api huma.API) {
 	}, func(ctx context.Context, _ *struct{}) (*ListUsersOutput, error) {
 		list, err := listUsers()
 		if err != nil {
-			return nil, huma.Error500InternalServerError("read "+passwdPath+" failed", err)
+			return nil, huma.Error500InternalServerError("user lookup failed", err)
 		}
 		out := &ListUsersOutput{}
 		out.Body.Users = list
@@ -127,7 +128,7 @@ func registerUsers(api huma.API) {
 		}
 		u, ok, err := lookupUser(in.Username)
 		if err != nil {
-			return nil, huma.Error500InternalServerError("read "+passwdPath+" failed", err)
+			return nil, huma.Error500InternalServerError("user lookup failed", err)
 		}
 		if !ok {
 			return nil, huma.Error404NotFound("user not found: " + in.Username)
@@ -163,7 +164,7 @@ func registerUsers(api huma.API) {
 			return nil, huma.Error400BadRequest("home must be an absolute path")
 		}
 		if _, ok, err := lookupUser(in.Body.Username); err != nil {
-			return nil, huma.Error500InternalServerError("read "+passwdPath+" failed", err)
+			return nil, huma.Error500InternalServerError("user lookup failed", err)
 		} else if ok {
 			return nil, huma.Error409Conflict("user already exists: " + in.Body.Username)
 		}
@@ -212,7 +213,7 @@ func registerUsers(api huma.API) {
 			return nil, err
 		}
 		if _, ok, err := lookupUser(in.Username); err != nil {
-			return nil, huma.Error500InternalServerError("read "+passwdPath+" failed", err)
+			return nil, huma.Error500InternalServerError("user lookup failed", err)
 		} else if !ok {
 			return nil, huma.Error404NotFound("user not found: " + in.Username)
 		}
@@ -253,7 +254,7 @@ func registerUsers(api huma.API) {
 			return nil, huma.Error400BadRequest("password may not contain newlines")
 		}
 		if _, ok, err := lookupUser(in.Username); err != nil {
-			return nil, huma.Error500InternalServerError("read "+passwdPath+" failed", err)
+			return nil, huma.Error500InternalServerError("user lookup failed", err)
 		} else if !ok {
 			return nil, huma.Error404NotFound("user not found: " + in.Username)
 		}
@@ -261,6 +262,11 @@ func registerUsers(api huma.API) {
 		if _, err := oscmd.RunStdin(in.Username+":"+in.Body.Password+"\n", "chpasswd"); err != nil {
 			return nil, huma.Error500InternalServerError("chpasswd failed", err)
 		}
+		if sessions != nil {
+			if err := sessions.DeleteByUsername(in.Username); err != nil {
+				log.Printf("failed to invalidate sessions for %s: %v", in.Username, err)
+			}
+		}
 		return oscmd.OK(), nil
 	})
 
@@ -290,7 +296,7 @@ func registerUsers(api huma.API) {
 			}
 		}
 		if _, ok, err := lookupUser(in.Username); err != nil {
-			return nil, huma.Error500InternalServerError("read "+passwdPath+" failed", err)
+			return nil, huma.Error500InternalServerError("user lookup failed", err)
 		} else if !ok {
 			return nil, huma.Error404NotFound("user not found: " + in.Username)
 		}

internal/modules/users/users_handler_test.go

@@ -28,7 +28,7 @@ func TestUsersHandlers(t *testing.T) {
 
 	mux := http.NewServeMux()
 	api := humatest.Wrap(t, humago.New(mux, huma.DefaultConfig("Test", "1.0.0")))
-	registerUsers(api)
+	registerUsers(api, nil)
 
 	// 1. Test GET /api/users
 	resp := api.Get("/api/users")

internal/modules/users/users_test.go

@@ -28,26 +28,34 @@ short:x:2:2
 }
 
 func TestValidateUsername(t *testing.T) {
-	valid := []string{"alice", "_svc", "user-1", "a", "machine$", "abc_def"}
-	for _, n := range valid {
-		if err := validateUsername(n); err != nil {
-			t.Errorf("validateUsername(%q) = %v, want nil", n, err)
-		}
-	}
-
-	invalid := []string{
-		"",       // empty
-		"-rf",    // leading dash (flag injection)
-		"Alice",  // uppercase
-		"1user",  // leading digit
-		"a b",    // space
-		"foo;rm", // shell metachar
-		"root:x", // colon (passwd separator)
-		"waytoolongusernamethatexceedsthirtytwochars", // >32
-	}
-	for _, n := range invalid {
-		if err := validateUsername(n); err == nil {
-			t.Errorf("validateUsername(%q) = nil, want error", n)
-		}
+	for _, n := range []struct {
+		name  string
+		value string
+		valid bool
+	}{
+		{name: "alice", value: "alice", valid: true},
+		{name: "underscore prefix", value: "_svc", valid: true},
+		{name: "hyphen", value: "user-1", valid: true},
+		{name: "single char", value: "a", valid: true},
+		{name: "dollar suffix", value: "machine$", valid: true},
+		{name: "underscore", value: "abc_def", valid: true},
+		{name: "empty", value: "", valid: false},
+		{name: "leading dash", value: "-rf", valid: false},
+		{name: "uppercase", value: "Alice", valid: false},
+		{name: "leading digit", value: "1user", valid: false},
+		{name: "space", value: "a b", valid: false},
+		{name: "shell metachar", value: "foo;rm", valid: false},
+		{name: "colon", value: "root:x", valid: false},
+		{name: "too long", value: "waytoolongusernamethatexceedsthirtytwochars", valid: false},
+	} {
+		t.Run(n.name, func(t *testing.T) {
+			err := validateUsername(n.value)
+			if n.valid && err != nil {
+				t.Errorf("validateUsername(%q) = %v, want nil", n.value, err)
+			}
+			if !n.valid && err == nil {
+				t.Errorf("validateUsername(%q) = nil, want error", n.value)
+			}
+		})
 	}
 }

internal/mounts/mounts_test.go

@@ -25,16 +25,22 @@ func TestParseProc(t *testing.T) {
 }
 
 func TestUnescape(t *testing.T) {
-	cases := map[string]string{
-		`/mnt/my\040disk`: "/mnt/my disk",
-		`/no/escapes`:     "/no/escapes",
-		`tab\011here`:     "tab\there",
-		`back\134slash`:   `back\slash`,
+	tests := []struct {
+		name string
+		in   string
+		want string
+	}{
+		{name: "octal space", in: `/mnt/my\040disk`, want: "/mnt/my disk"},
+		{name: "no escapes", in: `/no/escapes`, want: "/no/escapes"},
+		{name: "tab", in: `tab\011here`, want: "tab\there"},
+		{name: "backslash", in: `back\134slash`, want: `back\slash`},
 	}
-	for in, want := range cases {
-		if got := Unescape(in); got != want {
-			t.Errorf("Unescape(%q) = %q, want %q", in, got, want)
-		}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := Unescape(tt.in); got != tt.want {
+				t.Errorf("Unescape(%q) = %q, want %q", tt.in, got, tt.want)
+			}
+		})
 	}
 }
 

internal/openapitest/openapi_test.go

@@ -14,14 +14,12 @@ import (
 	"nadir/internal/auth"
 	"nadir/internal/meta"
 	"nadir/internal/module"
-	"nadir/internal/modules/audit"
 	"nadir/internal/modules/groups"
 	"nadir/internal/modules/networking"
 	"nadir/internal/modules/packages"
 	"nadir/internal/modules/services"
 	"nadir/internal/modules/storage"
 	"nadir/internal/modules/system"
-	"nadir/internal/modules/terminal"
 	"nadir/internal/modules/users"
 	"nadir/internal/rbac"
 
@@ -29,6 +27,12 @@ import (
 	"github.com/danielgtaylor/huma/v2/adapters/humago"
 )
 
+type auditModule struct{}
+
+func (auditModule) ID() string                     { return "audit" }
+func (auditModule) Permissions() []rbac.Permission { return []rbac.Permission{rbac.Read} }
+func (auditModule) Register(huma.API)              {}
+
 func TestOpenAPISchemaNoCollisions(t *testing.T) {
 	auditStore, err := auditlog.New(filepath.Join(t.TempDir(), "audit.db"))
 	if err != nil {
@@ -44,13 +48,12 @@ func TestOpenAPISchemaNoCollisions(t *testing.T) {
 	mods := []module.Module{
 		system.New(),
 		services.New(nil),
-		users.New(),
+		users.New(nil),
 		groups.New(),
 		packages.New(),
 		networking.New(),
 		storage.New(),
-		audit.New(auditStore),
-		terminal.New(sessions),
+		auditModule{},
 	}
 
 	mux := http.NewServeMux()
@@ -61,6 +64,7 @@ func TestOpenAPISchemaNoCollisions(t *testing.T) {
 	meta.Register(api, mods)
 	meta.RegisterHealth(api, sessions)
 	meta.RegisterWhoami(api, sessions, nil, roles, mods)
+	meta.RegisterAudit(api, auditStore)
 	auth.RegisterLogin(api, sessions, auditStore, true)
 	auth.RegisterLogout(api, sessions, true)
 

internal/oscmd/oscmd.go

@@ -14,6 +14,7 @@ import (
 	"os/exec"
 	"strings"
 	"sync"
+	"syscall"
 	"time"
 )
 
@@ -276,6 +277,23 @@ func ParseKV(lines []string) map[string]string {
 	return m
 }
 
+// RunDetached starts name with args in a new process group (Setsid) and returns
+// immediately once the child has started. The child is reaped in the background
+// so it does not become a zombie.
+//
+// Use this for operations where the synchronous path would kill the caller
+// (e.g. "systemctl restart nadir" would SIGTERM the process serving the
+// request before the response is written).
+func RunDetached(name string, args ...string) (*StatusOutput, error) {
+	cmd := exec.Command(name, args...)
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setsid: true}
+	if err := cmd.Start(); err != nil {
+		return nil, err
+	}
+	go cmd.Wait()
+	return OK(), nil
+}
+
 // StatusOutput is the shared response for write operations that just report
 // success. Reusing one type means all such endpoints share a single OpenAPI
 // schema.

internal/rbac/middleware_test.go

@@ -41,8 +41,6 @@ func TestRbacMiddleware(t *testing.T) {
 		},
 	})
 	r.AssignRole("alice", "test-role")
-	// A machine credential is just another RBAC subject: the token name is
-	// assigned a role exactly like a username.
 	r.AssignRole("dash", "test-role")
 
 	mux := http.NewServeMux()
@@ -76,81 +74,91 @@ func TestRbacMiddleware(t *testing.T) {
 		return &struct{ Body string }{Body: "gated-write"}, nil
 	})
 
-	// 1. Test public route
-	resp := api.Get("/public")
-	if resp.Code != http.StatusOK {
-		t.Errorf("public GET: got status %d, want %d", resp.Code, http.StatusOK)
-	}
+	t.Run("public route", func(t *testing.T) {
+		resp := api.Get("/public")
+		if resp.Code != http.StatusOK {
+			t.Errorf("got status %d, want %d", resp.Code, http.StatusOK)
+		}
+	})
 
-	// 2. Test gated route without cookie -> 401 Unauthorized
-	resp = api.Get("/gated-read")
-	if resp.Code != http.StatusUnauthorized {
-		t.Errorf("gated GET no cookie: got status %d, want %d", resp.Code, http.StatusUnauthorized)
-	}
+	t.Run("no auth returns 401", func(t *testing.T) {
+		resp := api.Get("/gated-read")
+		if resp.Code != http.StatusUnauthorized {
+			t.Errorf("got status %d, want %d", resp.Code, http.StatusUnauthorized)
+		}
+	})
 
-	// 3. Test gated route with invalid cookie -> 401 Unauthorized
-	resp = api.Get("/gated-read", "Cookie: nadir_session_id=invalid")
-	if resp.Code != http.StatusUnauthorized {
-		t.Errorf("gated GET invalid cookie: got status %d, want %d", resp.Code, http.StatusUnauthorized)
-	}
+	t.Run("invalid cookie returns 401", func(t *testing.T) {
+		resp := api.Get("/gated-read", "Cookie: nadir_session_id=invalid")
+		if resp.Code != http.StatusUnauthorized {
+			t.Errorf("got status %d, want %d", resp.Code, http.StatusUnauthorized)
+		}
+	})
 
-	// Create valid session
-	token, err := sessions.Create("alice")
-	if err != nil {
-		t.Fatal(err)
-	}
+	var aliceToken string
+	t.Run("valid session returns 200", func(t *testing.T) {
+		var err error
+		aliceToken, err = sessions.Create("alice")
+		if err != nil {
+			t.Fatal(err)
+		}
+		resp := api.Get("/gated-read", "Cookie: nadir_session_id="+aliceToken)
+		if resp.Code != http.StatusOK {
+			t.Errorf("got status %d, want %d", resp.Code, http.StatusOK)
+		}
+	})
 
-	// 4. Test gated route with valid cookie -> 200 OK
-	resp = api.Get("/gated-read", "Cookie: nadir_session_id="+token)
-	if resp.Code != http.StatusOK {
-		t.Errorf("gated GET valid cookie: got status %d, want %d", resp.Code, http.StatusOK)
-	}
+	t.Run("csrf mismatched origin returns 403", func(t *testing.T) {
+		resp := api.Post("/gated-write", "Cookie: nadir_session_id="+aliceToken, "Origin: http://evil.com", "Host: example.com", struct{}{})
+		if resp.Code != http.StatusForbidden {
+			t.Errorf("got status %d, want %d", resp.Code, http.StatusForbidden)
+		}
+	})
 
-	// 5. Test CSRF violation: POST with mismatched Origin header -> 403 Forbidden
-	resp = api.Post("/gated-write", "Cookie: nadir_session_id="+token, "Origin: http://evil.com", "Host: example.com", struct{}{})
-	if resp.Code != http.StatusForbidden {
-		t.Errorf("CSRF mismatched Origin: got status %d, want %d", resp.Code, http.StatusForbidden)
-	}
+	t.Run("csrf matching origin returns 200", func(t *testing.T) {
+		resp := api.Post("/gated-write", "Cookie: nadir_session_id="+aliceToken, "Origin: http://example.com", "Host: example.com", struct{}{})
+		if resp.Code != http.StatusOK {
+			t.Errorf("got status %d, want %d", resp.Code, http.StatusOK)
+		}
+	})
 
-	// 6. Test CSRF success: POST with matching Origin header -> 200 OK
-	resp = api.Post("/gated-write", "Cookie: nadir_session_id="+token, "Origin: http://example.com", "Host: example.com", struct{}{})
-	if resp.Code != http.StatusOK {
-		t.Errorf("CSRF matching Origin: got status %d, want %d", resp.Code, http.StatusOK)
-	}
+	t.Run("unauthorized user returns 403", func(t *testing.T) {
+		bobToken, err := sessions.Create("bob")
+		if err != nil {
+			t.Fatal(err)
+		}
+		resp := api.Get("/gated-read", "Cookie: nadir_session_id="+bobToken)
+		if resp.Code != http.StatusForbidden {
+			t.Errorf("got status %d, want %d", resp.Code, http.StatusForbidden)
+		}
+	})
 
-	// 7. Test gated route with unauthorized user -> 403 Forbidden
-	tokenBob, err := sessions.Create("bob")
-	if err != nil {
-		t.Fatal(err)
-	}
-	resp = api.Get("/gated-read", "Cookie: nadir_session_id="+tokenBob)
-	if resp.Code != http.StatusForbidden {
-		t.Errorf("bob unauthorized GET: got status %d, want %d", resp.Code, http.StatusForbidden)
-	}
+	t.Run("valid bearer token returns 200", func(t *testing.T) {
+		rawToken, err := tokenStore.Create("dash")
+		if err != nil {
+			t.Fatal(err)
+		}
+		resp := api.Get("/gated-read", "Authorization: Bearer "+rawToken)
+		if resp.Code != http.StatusOK {
+			t.Errorf("got status %d, want %d", resp.Code, http.StatusOK)
+		}
+	})
 
-	// 8. Bearer token for an assigned name -> 200 OK
-	rawToken, err := tokenStore.Create("dash")
-	if err != nil {
-		t.Fatal(err)
-	}
-	resp = api.Get("/gated-read", "Authorization: Bearer "+rawToken)
-	if resp.Code != http.StatusOK {
-		t.Errorf("valid bearer GET: got status %d, want %d", resp.Code, http.StatusOK)
-	}
+	t.Run("bogus bearer token returns 401", func(t *testing.T) {
+		resp := api.Get("/gated-read", "Authorization: Bearer nad_deadbeef")
+		if resp.Code != http.StatusUnauthorized {
+			t.Errorf("got status %d, want %d", resp.Code, http.StatusUnauthorized)
+		}
+	})
 
-	// 9. Bogus bearer token -> 401 Unauthorized
-	resp = api.Get("/gated-read", "Authorization: Bearer nad_deadbeef")
-	if resp.Code != http.StatusUnauthorized {
-		t.Errorf("bogus bearer GET: got status %d, want %d", resp.Code, http.StatusUnauthorized)
-	}
-
-	// 10. Bearer token with no role assignment -> 403 Forbidden
-	rawUnassigned, err := tokenStore.Create("orphan")
-	if err != nil {
-		t.Fatal(err)
-	}
-	resp = api.Get("/gated-read", "Authorization: Bearer "+rawUnassigned)
-	if resp.Code != http.StatusForbidden {
-		t.Errorf("unassigned bearer GET: got status %d, want %d", resp.Code, http.StatusForbidden)
-	}
+	t.Run("unassigned bearer token returns 403", func(t *testing.T) {
+		rawUnassigned, err := tokenStore.Create("orphan")
+		if err != nil {
+			t.Fatal(err)
+		}
+		resp := api.Get("/gated-read", "Authorization: Bearer "+rawUnassigned)
+		if resp.Code != http.StatusForbidden {
+			t.Errorf("got status %d, want %d", resp.Code, http.StatusForbidden)
+		}
+	})
 }