summaryrefslogtreecommitdiff
path: root/src/shared/rm-rf.c
blob: eeb2e3919659a3d9a7a051dd1b5af915579a66c5 (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
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

/***
  This file is part of systemd.

  Copyright 2015 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 "util.h"
#include "path-util.h"
#include "rm-rf.h"

int rm_rf_children(int fd, RemoveFlags flags, struct stat *root_dev) {
        _cleanup_closedir_ DIR *d = NULL;
        int ret = 0, r;

        assert(fd >= 0);

        /* This returns the first error we run into, but nevertheless
         * tries to go on. This closes the passed fd. */

        if (!(flags & REMOVE_PHYSICAL)) {

                r = fd_is_temporary_fs(fd);
                if (r < 0) {
                        safe_close(fd);
                        return r;
                }

                if (!r) {
                        /* We refuse to clean physical file systems
                         * with this call, unless explicitly
                         * requested. This is extra paranoia just to
                         * be sure we never ever remove non-state
                         * data */

                        log_error("Attempted to remove disk file system, and we can't allow that.");
                        safe_close(fd);
                        return -EPERM;
                }
        }

        d = fdopendir(fd);
        if (!d) {
                safe_close(fd);
                return errno == ENOENT ? 0 : -errno;
        }

        for (;;) {
                struct dirent *de;
                bool is_dir;
                struct stat st;

                errno = 0;
                de = readdir(d);
                if (!de) {
                        if (errno != 0 && ret == 0)
                                ret = -errno;
                        return ret;
                }

                if (streq(de->d_name, ".") || streq(de->d_name, ".."))
                        continue;

                if (de->d_type == DT_UNKNOWN || (de->d_type == DT_DIR && root_dev)) {
                        if (fstatat(fd, de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) {
                                if (ret == 0 && errno != ENOENT)
                                        ret = -errno;
                                continue;
                        }

                        is_dir = S_ISDIR(st.st_mode);
                } else
                        is_dir = de->d_type == DT_DIR;

                if (is_dir) {
                        int subdir_fd;

                        /* if root_dev is set, remove subdirectories only if device is same */
                        if (root_dev && st.st_dev != root_dev->st_dev)
                                continue;

                        subdir_fd = openat(fd, de->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
                        if (subdir_fd < 0) {
                                if (ret == 0 && errno != ENOENT)
                                        ret = -errno;
                                continue;
                        }

                        /* Stop at mount points */
                        r = fd_is_mount_point(subdir_fd);
                        if (r < 0) {
                                if (ret == 0 && r != -ENOENT)
                                        ret = r;

                                safe_close(subdir_fd);
                                continue;
                        }
                        if (r) {
                                safe_close(subdir_fd);
                                continue;
                        }

                        /* We pass REMOVE_PHYSICAL here, to avoid
                         * doing the fstatfs() to check the file
                         * system type again for each directory */
                        r = rm_rf_children(subdir_fd, flags | REMOVE_PHYSICAL, root_dev);
                        if (r < 0 && ret == 0)
                                ret = r;

                        if (unlinkat(fd, de->d_name, AT_REMOVEDIR) < 0) {
                                if (ret == 0 && errno != ENOENT)
                                        ret = -errno;
                        }

                } else if (!(flags & REMOVE_ONLY_DIRECTORIES)) {

                        if (unlinkat(fd, de->d_name, 0) < 0) {
                                if (ret == 0 && errno != ENOENT)
                                        ret = -errno;
                        }
                }
        }
}

int rm_rf(const char *path, RemoveFlags flags) {
        int fd, r;
        struct statfs s;

        assert(path);

        /* We refuse to clean the root file system with this
         * call. This is extra paranoia to never cause a really
         * seriously broken system. */
        if (path_equal(path, "/")) {
                log_error("Attempted to remove entire root file system, and we can't allow that.");
                return -EPERM;
        }

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

                if (errno != ENOTDIR && errno != ELOOP)
                        return -errno;

                if (!(flags & REMOVE_PHYSICAL)) {
                        if (statfs(path, &s) < 0)
                                return -errno;

                        if (!is_temporary_fs(&s)) {
                                log_error("Attempted to remove disk file system, and we can't allow that.");
                                return -EPERM;
                        }
                }

                if ((flags & REMOVE_ROOT) && !(flags & REMOVE_ONLY_DIRECTORIES))
                        if (unlink(path) < 0 && errno != ENOENT)
                                return -errno;

                return 0;
        }

        r = rm_rf_children(fd, flags, NULL);

        if (flags & REMOVE_ROOT) {
                if (rmdir(path) < 0 && errno != ENOENT) {
                        if (r == 0)
                                r = -errno;
                }
        }

        return r;
}