Shares of other services and RepoISO integration

- include SMB drop-ins from /etc/samba/smb.conf.d into the generated smb.conf
- keep smbd/nfs-server running while other services (/etc/exports.d, drop-ins) share,
  instead of disabling them when nasmon has no shares of its own
- list those shares read-only on /shares
- settings: RepoISO URL; poll its /api/integration/status, dashboard card, menu link,
  alerts for portal down, stale worker, failed jobs, unmounted publications

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/shares/external.go

@@ -0,0 +1,128 @@
+package shares
+
+import (
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+)
+
+// Other services on the host (e.g. RepoISO) publish their own shares through
+// drop-in files. nasmon includes the SMB drop-ins into the smb.conf it
+// generates and keeps smbd / nfs-server running while any of them define a
+// share, even when nasmon itself has none.
+const (
+	DefaultSMBIncludeDir = "/etc/samba/smb.conf.d"
+	DefaultExportsDir    = "/etc/exports.d"
+)
+
+// ExternalShare is a share defined outside nasmon (read-only in the UI).
+type ExternalShare struct {
+	Kind    string // smb | nfs
+	Source  string // drop-in file name without extension, e.g. "repoiso"
+	Name    string // SMB share name (empty for NFS)
+	Path    string
+	Clients string // NFS clients with options, as written in the file
+}
+
+// IncludeFiles lists the *.conf drop-ins in dir, sorted. A missing dir yields nil.
+func IncludeFiles(dir string) []string {
+	if dir == "" {
+		return nil
+	}
+	m, _ := filepath.Glob(filepath.Join(dir, "*.conf"))
+	sort.Strings(m)
+	return m
+}
+
+func sourceName(file string) string {
+	return strings.TrimSuffix(filepath.Base(file), filepath.Ext(file))
+}
+
+// ParseSMBDropIn returns the shares ([section] other than [global], [homes],
+// [printers]) defined in a Samba config fragment.
+func ParseSMBDropIn(text, source string) []ExternalShare {
+	var out []ExternalShare
+	var cur *ExternalShare
+	for _, raw := range strings.Split(text, "\n") {
+		line := strings.TrimSpace(raw)
+		if line == "" || line[0] == '#' || line[0] == ';' {
+			continue
+		}
+		if strings.HasPrefix(line, "[") && strings.HasSuffix(line, "]") {
+			name := strings.TrimSpace(line[1 : len(line)-1])
+			switch strings.ToLower(name) {
+			case "global", "homes", "printers":
+				cur = nil
+			default:
+				out = append(out, ExternalShare{Kind: "smb", Source: source, Name: name})
+				cur = &out[len(out)-1]
+			}
+			continue
+		}
+		if cur == nil {
+			continue
+		}
+		if k, v, ok := strings.Cut(line, "="); ok && strings.EqualFold(strings.TrimSpace(k), "path") {
+			cur.Path = strings.TrimSpace(v)
+		}
+	}
+	return out
+}
+
+// ParseExportsFile returns the exports in an exports(5) file.
+func ParseExportsFile(text, source string) []ExternalShare {
+	var out []ExternalShare
+	for _, raw := range strings.Split(text, "\n") {
+		line := strings.TrimSpace(raw)
+		if line == "" || line[0] == '#' {
+			continue
+		}
+		var path, rest string
+		if line[0] == '"' {
+			if end := strings.Index(line[1:], `"`); end >= 0 {
+				path, rest = line[1:end+1], line[end+2:]
+			}
+		} else {
+			path, rest, _ = strings.Cut(line, " ")
+		}
+		if path == "" {
+			continue
+		}
+		out = append(out, ExternalShare{Kind: "nfs", Source: source, Path: path, Clients: strings.TrimSpace(rest)})
+	}
+	return out
+}
+
+// External reads the SMB drop-ins and the exports.d files of other services.
+func (m *Manager) External() []ExternalShare {
+	var out []ExternalShare
+	for _, f := range IncludeFiles(m.IncludeDir) {
+		if b, err := os.ReadFile(f); err == nil {
+			out = append(out, ParseSMBDropIn(string(b), sourceName(f))...)
+		}
+	}
+	if m.ExportsDir != "" {
+		files, _ := filepath.Glob(filepath.Join(m.ExportsDir, "*.exports"))
+		sort.Strings(files)
+		for _, f := range files {
+			if filepath.Clean(f) == filepath.Clean(m.Exports) {
+				continue
+			}
+			if b, err := os.ReadFile(f); err == nil {
+				out = append(out, ParseExportsFile(string(b), sourceName(f))...)
+			}
+		}
+	}
+	return out
+}
+
+func countKind(ext []ExternalShare, kind string) int {
+	n := 0
+	for _, e := range ext {
+		if e.Kind == kind {
+			n++
+		}
+	}
+	return n
+}