Release 2026.09.27.r001: support array disk rsync backups to mounted USB disks

internal/platform/storage.go

@@ -0,0 +1,86 @@
+package platform
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+
+	"git.casaderoll.de/michael/urbm/internal/model"
+)
+
+var arrayDiskName = regexp.MustCompile(`^disk[1-9][0-9]*$`)
+
+func isArrayDiskPath(path string) bool {
+	parts := strings.Split(strings.TrimPrefix(filepath.Clean(path), "/"), "/")
+	return len(parts) >= 2 && parts[0] == "mnt" && arrayDiskName.MatchString(parts[1])
+}
+
+func mountedPaths() ([]string, error) {
+	data, err := os.ReadFile("/proc/self/mountinfo")
+	if err != nil {
+		return nil, err
+	}
+	return parseMountPaths(string(data)), nil
+}
+
+func parseMountPaths(data string) []string {
+	var paths []string
+	unescape := strings.NewReplacer(`\040`, " ", `\011`, "\t", `\012`, "\n", `\134`, `\`)
+	for _, line := range strings.Split(data, "\n") {
+		fields := strings.Fields(line)
+		if len(fields) >= 10 {
+			paths = append(paths, unescape.Replace(fields[4]))
+		}
+	}
+	return paths
+}
+
+func storageBrowseRoots(mounts []string) []string {
+	roots := append([]string{}, browseRoots...)
+	seen := make(map[string]bool)
+	for _, mount := range mounts {
+		if filepath.Dir(mount) == "/mnt" && isArrayDiskPath(mount) && !seen[mount] {
+			roots = append(roots, mount)
+			seen[mount] = true
+		}
+	}
+	return roots
+}
+
+func pathUnder(path, root string) bool {
+	return path == root || strings.HasPrefix(path, root+string(os.PathSeparator))
+}
+
+// Require an actual mount for removable disks and array sources. An empty
+// directory left behind by an unmount must never become a backup destination.
+func validateRsyncMounts(job model.Job, mounts []string) error {
+	paths := []string{job.Rsync.Target}
+	for _, source := range job.Sources {
+		paths = append(paths, source.Path)
+	}
+	for _, path := range paths {
+		clean := filepath.Clean(path)
+		if !isArrayDiskPath(clean) && !pathUnder(clean, "/mnt/disks") {
+			continue
+		}
+		resolved, err := filepath.EvalSymlinks(clean)
+		if err != nil {
+			return fmt.Errorf("environment: rsync disk unavailable: %s: %w", clean, err)
+		}
+		if !diskPathMounted(resolved, mounts) {
+			return fmt.Errorf("environment: rsync disk is not mounted: %s", clean)
+		}
+	}
+	return nil
+}
+
+func diskPathMounted(resolved string, mounts []string) bool {
+	for _, mount := range mounts {
+		if ((isArrayDiskPath(mount) && filepath.Dir(mount) == "/mnt") || strings.HasPrefix(mount, "/mnt/disks/")) && pathUnder(resolved, mount) {
+			return true
+		}
+	}
+	return false
+}