Line data Source code
1 : /* SPDX-License-Identifier: LGPL-2.1+ */
2 :
3 : #include <errno.h>
4 : #include <fcntl.h>
5 : #include <stdbool.h>
6 : #include <stddef.h>
7 : #include <sys/stat.h>
8 : #include <sys/statfs.h>
9 : #include <unistd.h>
10 :
11 : #include "alloc-util.h"
12 : #include "btrfs-util.h"
13 : #include "cgroup-util.h"
14 : #include "dirent-util.h"
15 : #include "fd-util.h"
16 : #include "log.h"
17 : #include "macro.h"
18 : #include "mountpoint-util.h"
19 : #include "path-util.h"
20 : #include "rm-rf.h"
21 : #include "stat-util.h"
22 : #include "string-util.h"
23 :
24 0 : static bool is_physical_fs(const struct statfs *sfs) {
25 0 : return !is_temporary_fs(sfs) && !is_cgroup_fs(sfs);
26 : }
27 :
28 117 : int rm_rf_children(int fd, RemoveFlags flags, struct stat *root_dev) {
29 117 : _cleanup_closedir_ DIR *d = NULL;
30 : struct dirent *de;
31 117 : int ret = 0, r;
32 : struct statfs sfs;
33 :
34 117 : assert(fd >= 0);
35 :
36 : /* This returns the first error we run into, but nevertheless tries to go on. This closes the passed
37 : * fd, in all cases, including on failure.. */
38 :
39 117 : if (!(flags & REMOVE_PHYSICAL)) {
40 :
41 0 : r = fstatfs(fd, &sfs);
42 0 : if (r < 0) {
43 0 : safe_close(fd);
44 0 : return -errno;
45 : }
46 :
47 0 : if (is_physical_fs(&sfs)) {
48 : /* We refuse to clean physical file systems with this call,
49 : * unless explicitly requested. This is extra paranoia just
50 : * to be sure we never ever remove non-state data. */
51 0 : _cleanup_free_ char *path = NULL;
52 :
53 0 : (void) fd_get_path(fd, &path);
54 0 : log_error("Attempted to remove disk file system under \"%s\", and we can't allow that.",
55 : strna(path));
56 :
57 0 : safe_close(fd);
58 0 : return -EPERM;
59 : }
60 : }
61 :
62 117 : d = fdopendir(fd);
63 117 : if (!d) {
64 0 : safe_close(fd);
65 0 : return errno == ENOENT ? 0 : -errno;
66 : }
67 :
68 33693 : FOREACH_DIRENT_ALL(de, d, return -errno) {
69 : bool is_dir;
70 : struct stat st;
71 :
72 33576 : if (dot_or_dot_dot(de->d_name))
73 234 : continue;
74 :
75 33342 : if (de->d_type == DT_UNKNOWN ||
76 33342 : (de->d_type == DT_DIR && (root_dev || (flags & REMOVE_SUBVOLUME)))) {
77 0 : if (fstatat(fd, de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) {
78 0 : if (ret == 0 && errno != ENOENT)
79 0 : ret = -errno;
80 0 : continue;
81 : }
82 :
83 0 : is_dir = S_ISDIR(st.st_mode);
84 : } else
85 33342 : is_dir = de->d_type == DT_DIR;
86 :
87 33342 : if (is_dir) {
88 52 : _cleanup_close_ int subdir_fd = -1;
89 :
90 : /* if root_dev is set, remove subdirectories only if device is same */
91 52 : if (root_dev && st.st_dev != root_dev->st_dev)
92 0 : continue;
93 :
94 52 : subdir_fd = openat(fd, de->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
95 52 : if (subdir_fd < 0) {
96 0 : if (ret == 0 && errno != ENOENT)
97 0 : ret = -errno;
98 0 : continue;
99 : }
100 :
101 : /* Stop at mount points */
102 52 : r = fd_is_mount_point(fd, de->d_name, 0);
103 52 : if (r < 0) {
104 0 : if (ret == 0 && r != -ENOENT)
105 0 : ret = r;
106 :
107 0 : continue;
108 : }
109 52 : if (r > 0)
110 0 : continue;
111 :
112 52 : if ((flags & REMOVE_SUBVOLUME) && st.st_ino == 256) {
113 :
114 : /* This could be a subvolume, try to remove it */
115 :
116 0 : r = btrfs_subvol_remove_fd(fd, de->d_name, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA);
117 0 : if (r < 0) {
118 0 : if (!IN_SET(r, -ENOTTY, -EINVAL)) {
119 0 : if (ret == 0)
120 0 : ret = r;
121 :
122 0 : continue;
123 : }
124 :
125 : /* ENOTTY, then it wasn't a btrfs subvolume, continue below. */
126 : } else
127 : /* It was a subvolume, continue. */
128 0 : continue;
129 : }
130 :
131 : /* We pass REMOVE_PHYSICAL here, to avoid doing the fstatfs() to check the file
132 : * system type again for each directory */
133 52 : r = rm_rf_children(TAKE_FD(subdir_fd), flags | REMOVE_PHYSICAL, root_dev);
134 52 : if (r < 0 && ret == 0)
135 0 : ret = r;
136 :
137 52 : if (unlinkat(fd, de->d_name, AT_REMOVEDIR) < 0) {
138 0 : if (ret == 0 && errno != ENOENT)
139 0 : ret = -errno;
140 : }
141 :
142 33290 : } else if (!(flags & REMOVE_ONLY_DIRECTORIES)) {
143 :
144 33290 : if (unlinkat(fd, de->d_name, 0) < 0) {
145 0 : if (ret == 0 && errno != ENOENT)
146 0 : ret = -errno;
147 : }
148 : }
149 : }
150 117 : return ret;
151 : }
152 :
153 161 : int rm_rf(const char *path, RemoveFlags flags) {
154 : int fd, r;
155 : struct statfs s;
156 :
157 161 : assert(path);
158 :
159 : /* For now, don't support dropping subvols when also only dropping directories, since we can't do
160 : * this race-freely. */
161 161 : if (FLAGS_SET(flags, REMOVE_ONLY_DIRECTORIES|REMOVE_SUBVOLUME))
162 0 : return -EINVAL;
163 :
164 : /* We refuse to clean the root file system with this call. This is extra paranoia to never cause a
165 : * really seriously broken system. */
166 161 : if (path_equal_or_files_same(path, "/", AT_SYMLINK_NOFOLLOW))
167 0 : return log_error_errno(SYNTHETIC_ERRNO(EPERM),
168 : "Attempted to remove entire root file system (\"%s\"), and we can't allow that.",
169 : path);
170 :
171 161 : if (FLAGS_SET(flags, REMOVE_SUBVOLUME | REMOVE_ROOT | REMOVE_PHYSICAL)) {
172 : /* Try to remove as subvolume first */
173 0 : r = btrfs_subvol_remove(path, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA);
174 0 : if (r >= 0)
175 0 : return r;
176 :
177 0 : if (FLAGS_SET(flags, REMOVE_MISSING_OK) && r == -ENOENT)
178 0 : return 0;
179 :
180 0 : if (!IN_SET(r, -ENOTTY, -EINVAL, -ENOTDIR))
181 0 : return r;
182 :
183 : /* Not btrfs or not a subvolume */
184 : }
185 :
186 161 : fd = open(path, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
187 161 : if (fd < 0) {
188 96 : if (FLAGS_SET(flags, REMOVE_MISSING_OK) && errno == ENOENT)
189 0 : return 0;
190 :
191 96 : if (!IN_SET(errno, ENOTDIR, ELOOP))
192 90 : return -errno;
193 :
194 6 : if (FLAGS_SET(flags, REMOVE_ONLY_DIRECTORIES))
195 0 : return 0;
196 :
197 6 : if (FLAGS_SET(flags, REMOVE_ROOT)) {
198 :
199 6 : if (!FLAGS_SET(flags, REMOVE_PHYSICAL)) {
200 0 : if (statfs(path, &s) < 0)
201 0 : return -errno;
202 :
203 0 : if (is_physical_fs(&s))
204 0 : return log_error_errno(SYNTHETIC_ERRNO(EPERM),
205 : "Attempted to remove files from a disk file system under \"%s\", refusing.",
206 : path);
207 : }
208 :
209 6 : if (unlink(path) < 0) {
210 0 : if (FLAGS_SET(flags, REMOVE_MISSING_OK) && errno == ENOENT)
211 0 : return 0;
212 :
213 0 : return -errno;
214 : }
215 : }
216 :
217 6 : return 0;
218 : }
219 :
220 65 : r = rm_rf_children(fd, flags, NULL);
221 :
222 130 : if (FLAGS_SET(flags, REMOVE_ROOT) &&
223 65 : rmdir(path) < 0 &&
224 0 : r >= 0 &&
225 0 : (!FLAGS_SET(flags, REMOVE_MISSING_OK) || errno != ENOENT))
226 0 : r = -errno;
227 :
228 65 : return r;
229 : }
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