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
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
|
/* SPDX-License-Identifier: LGPL-2.1+ */
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stddef.h>
#include <unistd.h>
#include "alloc-util.h"
#include "btrfs-util.h"
#include "cgroup-util.h"
#include "dirent-util.h"
#include "fd-util.h"
#include "log.h"
#include "macro.h"
#include "mountpoint-util.h"
#include "path-util.h"
#include "rm-rf.h"
#include "stat-util.h"
#include "string-util.h"
static bool is_physical_fs(const struct statfs *sfs) {
return !is_temporary_fs(sfs) && !is_cgroup_fs(sfs);
}
static int unlinkat_harder(
int dfd,
const char *filename,
int unlink_flags,
RemoveFlags remove_flags) {
struct stat st;
int r;
/* Like unlinkat(), but tries harder: if we get EACCESS we'll try to set the r/w/x bits on the
* directory. This is useful if we run unprivileged and have some files where the w bit is
* missing. */
if (unlinkat(dfd, filename, unlink_flags) >= 0)
return 0;
if (errno != EACCES || !FLAGS_SET(remove_flags, REMOVE_CHMOD))
return -errno;
if (fstat(dfd, &st) < 0)
return -errno;
if (!S_ISDIR(st.st_mode))
return -ENOTDIR;
if (FLAGS_SET(st.st_mode, 0700)) /* Already set? */
return -EACCES; /* original error */
if (st.st_uid != geteuid()) /* this only works if the UID matches ours */
return -EACCES;
if (fchmod(dfd, (st.st_mode | 0700) & 07777) < 0)
return -errno;
if (unlinkat(dfd, filename, unlink_flags) < 0) {
r = -errno;
/* Try to restore the original access mode if this didn't work */
(void) fchmod(dfd, st.st_mode & 07777);
return r;
}
return 0;
}
int rm_rf_children(int fd, RemoveFlags flags, struct stat *root_dev) {
_cleanup_closedir_ DIR *d = NULL;
struct dirent *de;
int ret = 0, r;
struct statfs sfs;
assert(fd >= 0);
/* This returns the first error we run into, but nevertheless tries to go on. This closes the passed
* fd, in all cases, including on failure.. */
if (!(flags & REMOVE_PHYSICAL)) {
r = fstatfs(fd, &sfs);
if (r < 0) {
safe_close(fd);
return -errno;
}
if (is_physical_fs(&sfs)) {
/* 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. */
_cleanup_free_ char *path = NULL;
(void) fd_get_path(fd, &path);
log_error("Attempted to remove disk file system under \"%s\", and we can't allow that.",
strna(path));
safe_close(fd);
return -EPERM;
}
}
d = fdopendir(fd);
if (!d) {
safe_close(fd);
return errno == ENOENT ? 0 : -errno;
}
FOREACH_DIRENT_ALL(de, d, return -errno) {
bool is_dir;
struct stat st;
if (dot_or_dot_dot(de->d_name))
continue;
if (de->d_type == DT_UNKNOWN ||
(de->d_type == DT_DIR && (root_dev || (flags & REMOVE_SUBVOLUME)))) {
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) {
_cleanup_close_ int subdir_fd = -1;
/* 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(fd, de->d_name, 0);
if (r < 0) {
if (ret == 0 && r != -ENOENT)
ret = r;
continue;
}
if (r > 0)
continue;
if ((flags & REMOVE_SUBVOLUME) && st.st_ino == 256) {
/* This could be a subvolume, try to remove it */
r = btrfs_subvol_remove_fd(fd, de->d_name, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA);
if (r < 0) {
if (!IN_SET(r, -ENOTTY, -EINVAL)) {
if (ret == 0)
ret = r;
continue;
}
/* ENOTTY, then it wasn't a btrfs subvolume, continue below. */
} else
/* It was a subvolume, continue. */
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(TAKE_FD(subdir_fd), flags | REMOVE_PHYSICAL, root_dev);
if (r < 0 && ret == 0)
ret = r;
r = unlinkat_harder(fd, de->d_name, AT_REMOVEDIR, flags);
if (r < 0 && r != -ENOENT && ret == 0)
ret = r;
} else if (!(flags & REMOVE_ONLY_DIRECTORIES)) {
r = unlinkat_harder(fd, de->d_name, 0, flags);
if (r < 0 && r != -ENOENT && ret == 0)
ret = r;
}
}
return ret;
}
int rm_rf(const char *path, RemoveFlags flags) {
int fd, r;
struct statfs s;
assert(path);
/* For now, don't support dropping subvols when also only dropping directories, since we can't do
* this race-freely. */
if (FLAGS_SET(flags, REMOVE_ONLY_DIRECTORIES|REMOVE_SUBVOLUME))
return -EINVAL;
/* 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_or_files_same(path, "/", AT_SYMLINK_NOFOLLOW))
return log_error_errno(SYNTHETIC_ERRNO(EPERM),
"Attempted to remove entire root file system (\"%s\"), and we can't allow that.",
path);
if (FLAGS_SET(flags, REMOVE_SUBVOLUME | REMOVE_ROOT | REMOVE_PHYSICAL)) {
/* Try to remove as subvolume first */
r = btrfs_subvol_remove(path, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA);
if (r >= 0)
return r;
if (FLAGS_SET(flags, REMOVE_MISSING_OK) && r == -ENOENT)
return 0;
if (!IN_SET(r, -ENOTTY, -EINVAL, -ENOTDIR))
return r;
/* Not btrfs or not a subvolume */
}
fd = open(path, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
if (fd < 0) {
if (FLAGS_SET(flags, REMOVE_MISSING_OK) && errno == ENOENT)
return 0;
if (!IN_SET(errno, ENOTDIR, ELOOP))
return -errno;
if (FLAGS_SET(flags, REMOVE_ONLY_DIRECTORIES))
return 0;
if (FLAGS_SET(flags, REMOVE_ROOT)) {
if (!FLAGS_SET(flags, REMOVE_PHYSICAL)) {
if (statfs(path, &s) < 0)
return -errno;
if (is_physical_fs(&s))
return log_error_errno(SYNTHETIC_ERRNO(EPERM),
"Attempted to remove files from a disk file system under \"%s\", refusing.",
path);
}
if (unlink(path) < 0) {
if (FLAGS_SET(flags, REMOVE_MISSING_OK) && errno == ENOENT)
return 0;
return -errno;
}
}
return 0;
}
r = rm_rf_children(fd, flags, NULL);
if (FLAGS_SET(flags, REMOVE_ROOT) &&
rmdir(path) < 0 &&
r >= 0 &&
(!FLAGS_SET(flags, REMOVE_MISSING_OK) || errno != ENOENT))
r = -errno;
return r;
}
|
