feat: file and folder properties - mode, owner and group, applied to a folder's contents too (0.0.8)

internal/agent/fsprops.go

@@ -0,0 +1,163 @@
+package agent
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io/fs"
+	"os"
+	"os/user"
+	"path/filepath"
+	"sort"
+	"strconv"
+	"strings"
+	"syscall"
+
+	"github.com/x-grk/longpolling-remote-access/internal/proto"
+)
+
+// fsStat reports a file's properties, following a symlink to what it points
+// at, and the user and group names to choose an owner from.
+func fsStat(path string) (proto.FSStatResult, error) {
+	res := proto.FSStatResult{Path: path}
+	if li, err := os.Lstat(path); err == nil && li.Mode()&os.ModeSymlink != 0 {
+		res.Link, _ = os.Readlink(path)
+	}
+	info, err := os.Stat(path)
+	if err != nil {
+		return res, err
+	}
+	res.IsDir, res.Size, res.MTime = info.IsDir(), info.Size(), info.ModTime().Unix()
+	if st, ok := info.Sys().(*syscall.Stat_t); ok {
+		res.Mode = uint32(st.Mode) & 07777
+		res.UID, res.GID = int(st.Uid), int(st.Gid)
+	} else {
+		res.Mode = uint32(info.Mode().Perm())
+	}
+	res.Owner, res.Group = strconv.Itoa(res.UID), strconv.Itoa(res.GID)
+	if u, err := user.LookupId(res.Owner); err == nil {
+		res.Owner = u.Username
+	}
+	if g, err := user.LookupGroupId(res.Group); err == nil {
+		res.Group = g.Name
+	}
+	res.Users, res.Groups = namesIn("/etc/passwd"), namesIn("/etc/group")
+	return res, nil
+}
+
+// namesIn lists the first field of a passwd- or group-style file.
+func namesIn(file string) []string {
+	f, err := os.Open(file)
+	if err != nil {
+		return nil
+	}
+	defer f.Close()
+	var out []string
+	sc := bufio.NewScanner(f)
+	for sc.Scan() && len(out) < 1000 {
+		line := sc.Text()
+		if line == "" || line[0] == '#' {
+			continue
+		}
+		if name, _, ok := strings.Cut(line, ":"); ok && name != "" {
+			out = append(out, name)
+		}
+	}
+	sort.Strings(out)
+	return out
+}
+
+// lookupID resolves a user or group given by name or number; -1 for none.
+func lookupID(name string, group bool) (int, error) {
+	if name == "" {
+		return -1, nil
+	}
+	if n, err := strconv.Atoi(name); err == nil && n >= 0 {
+		return n, nil
+	}
+	if group {
+		g, err := user.LookupGroup(name)
+		if err != nil {
+			return -1, fmt.Errorf("группа %s не найдена", name)
+		}
+		return strconv.Atoi(g.Gid)
+	}
+	u, err := user.Lookup(name)
+	if err != nil {
+		return -1, fmt.Errorf("пользователь %s не найден", name)
+	}
+	return strconv.Atoi(u.Uid)
+}
+
+// fsChmod sets mode, owner and group on a path, and with Recursive on all
+// that is inside a folder. Symlinks inside are not followed.
+func fsChmod(a proto.FSChmodArgs) (any, error) {
+	if a.Path == "" {
+		return nil, errors.New("не указан путь")
+	}
+	if a.Recursive && filepath.Clean(a.Path) == "/" {
+		return nil, errors.New("отказ: рекурсивно для корня нельзя")
+	}
+	if a.Mode != nil && *a.Mode > 07777 {
+		return nil, errors.New("неверные права")
+	}
+	uid, err := lookupID(a.Owner, false)
+	if err != nil {
+		return nil, err
+	}
+	gid, err := lookupID(a.Group, true)
+	if err != nil {
+		return nil, err
+	}
+	changed, failed := 0, 0
+	var errs []string
+	// The path itself always gets the change; Only picks among what is in it.
+	apply := func(p string, isDir, isLink, self bool) {
+		if !self && ((a.Only == "files" && isDir) || (a.Only == "dirs" && !isDir)) {
+			return
+		}
+		var err error
+		if uid >= 0 || gid >= 0 {
+			err = os.Lchown(p, uid, gid)
+		}
+		// A symlink has no mode of its own: chmod would change its target.
+		if err == nil && a.Mode != nil && !isLink {
+			err = syscall.Chmod(p, *a.Mode)
+		}
+		if err != nil {
+			failed++
+			if len(errs) < 5 {
+				errs = append(errs, err.Error())
+			}
+			return
+		}
+		changed++
+	}
+	info, err := os.Stat(a.Path)
+	if err != nil {
+		return nil, err
+	}
+	if !a.Recursive || !info.IsDir() {
+		apply(a.Path, info.IsDir(), false, true)
+	} else {
+		err = filepath.WalkDir(a.Path, func(p string, d fs.DirEntry, err error) error {
+			if err != nil {
+				failed++
+				if len(errs) < 5 {
+					errs = append(errs, err.Error())
+				}
+				return nil
+			}
+			apply(p, d.IsDir(), d.Type()&fs.ModeSymlink != 0, p == a.Path)
+			return nil
+		})
+		if err != nil {
+			return nil, err
+		}
+	}
+	res := map[string]any{"changed": changed, "failed": failed, "errors": errs}
+	if failed > 0 && changed == 0 {
+		return res, errors.New(errs[0])
+	}
+	return res, nil
+}