aboutsummaryrefslogtreecommitdiff
blob: 2a3a0704f5ca23b106e5d1e75a8f9e248686c253 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
/***
  This file is part of systemd.

  Copyright 2017 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include "user-util.h"
#include "macro.h"
#include "fd-util.h"
#include "dirent-util.h"
#include "chown-recursive.h"

static int chown_one(int fd, const char *name, const struct stat *st, uid_t uid, gid_t gid) {
        int r;

        assert(fd >= 0);
        assert(st);

        if ((!uid_is_valid(uid) || st->st_uid == uid) &&
            (!gid_is_valid(gid) || st->st_gid == gid))
                return 0;

        if (name)
                r = fchownat(fd, name, uid, gid, AT_SYMLINK_NOFOLLOW);
        else
                r = fchown(fd, uid, gid);
        if (r < 0)
                return -errno;

        /* The linux kernel alters the mode in some cases of chown(). Let's undo this. */
        if (name) {
                if (!S_ISLNK(st->st_mode))
                        r = fchmodat(fd, name, st->st_mode, 0);
                else /* There's currently no AT_SYMLINK_NOFOLLOW for fchmodat() */
                        r = 0;
        } else
                r = fchmod(fd, st->st_mode);
        if (r < 0)
                return -errno;

        return 1;
}

static int chown_recursive_internal(int fd, const struct stat *st, uid_t uid, gid_t gid) {
        bool changed = false;
        int r;

        assert(fd >= 0);
        assert(st);

        if (S_ISDIR(st->st_mode)) {
                _cleanup_closedir_ DIR *d = NULL;
                struct dirent *de;

                d = fdopendir(fd);
                if (!d) {
                        r = -errno;
                        goto finish;
                }
                fd = -1;

                FOREACH_DIRENT_ALL(de, d, r = -errno; goto finish) {
                        struct stat fst;

                        if (dot_or_dot_dot(de->d_name))
                                continue;

                        if (fstatat(dirfd(d), de->d_name, &fst, AT_SYMLINK_NOFOLLOW) < 0) {
                                r = -errno;
                                goto finish;
                        }

                        if (S_ISDIR(fst.st_mode)) {
                                int subdir_fd;

                                subdir_fd = openat(dirfd(d), de->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
                                if (subdir_fd < 0) {
                                        r = -errno;
                                        goto finish;
                                }

                                r = chown_recursive_internal(subdir_fd, &fst, uid, gid);
                                if (r < 0)
                                        goto finish;
                                if (r > 0)
                                        changed = true;
                        } else {
                                r = chown_one(dirfd(d), de->d_name, &fst, uid, gid);
                                if (r < 0)
                                        goto finish;
                                if (r > 0)
                                        changed = true;
                        }
                }

                r = chown_one(dirfd(d), NULL, st, uid, gid);
        } else
                r = chown_one(fd, NULL, st, uid, gid);
        if (r < 0)
                goto finish;

        r = r > 0 || changed;

finish:
        safe_close(fd);
        return r;
}

int path_chown_recursive(const char *path, uid_t uid, gid_t gid) {
        _cleanup_close_ int fd = -1;
        struct stat st;
        int r;

        fd = open(path, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
        if (fd < 0)
                return -errno;

        if (!uid_is_valid(uid) && !gid_is_valid(gid))
                return 0; /* nothing to do */

        if (fstat(fd, &st) < 0)
                return -errno;

        /* Let's take a shortcut: if the top-level directory is properly owned, we don't descend into the whole tree,
         * under the assumption that all is OK anyway. */

        if ((!uid_is_valid(uid) || st.st_uid == uid) &&
            (!gid_is_valid(gid) || st.st_gid == gid))
                return 0;

        r = chown_recursive_internal(fd, &st, uid, gid);
        fd = -1; /* we donated the fd to the call, regardless if it succeeded or failed */

        return r;
}