Bug Summary

File:build-scan/../src/basic/fs-util.c
Warning:line 919, column 13
Potential leak of memory pointed to by 'done'

Annotated Source Code

Press '?' to see keyboard shortcuts

clang -cc1 -cc1 -triple x86_64-unknown-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name fs-util.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 2 -fhalf-no-semantic-interposition -mframe-pointer=all -relaxed-aliasing -menable-no-infs -menable-no-nans -menable-unsafe-fp-math -fno-signed-zeros -mreassociate -freciprocal-math -fdenormal-fp-math=preserve-sign,preserve-sign -ffp-contract=fast -fno-rounding-math -ffast-math -ffinite-math-only -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -fno-split-dwarf-inlining -debugger-tuning=gdb -resource-dir /usr/lib64/clang/12.0.0 -include config.h -I src/basic/libbasic.a.p -I src/basic -I ../src/basic -I src/shared -I ../src/shared -I src/systemd -I ../src/systemd -I src/journal -I ../src/journal -I src/journal-remote -I ../src/journal-remote -I src/nspawn -I ../src/nspawn -I src/resolve -I ../src/resolve -I src/timesync -I ../src/timesync -I ../src/time-wait-sync -I src/login -I ../src/login -I src/udev -I ../src/udev -I src/libudev -I ../src/libudev -I src/core -I ../src/core -I ../src/libsystemd/sd-bus -I ../src/libsystemd/sd-device -I ../src/libsystemd/sd-hwdb -I ../src/libsystemd/sd-id128 -I ../src/libsystemd/sd-netlink -I ../src/libsystemd/sd-network -I src/libsystemd-network -I ../src/libsystemd-network -I . -I .. -I /usr/include/blkid -I /usr/include/libmount -D _FILE_OFFSET_BITS=64 -internal-isystem /usr/local/include -internal-isystem /usr/lib64/clang/12.0.0/include -internal-externc-isystem /include -internal-externc-isystem /usr/include -Wwrite-strings -Wno-unused-parameter -Wno-missing-field-initializers -Wno-unused-result -Wno-format-signedness -Wno-error=nonnull -std=gnu99 -fconst-strings -fdebug-compilation-dir /home/mrc0mmand/repos/@redhat-plumbers/systemd-rhel8/build-scan -ferror-limit 19 -fvisibility default -stack-protector 2 -fgnuc-version=4.2.1 -fcolor-diagnostics -analyzer-output=html -faddrsig -o /tmp/scan-build-2021-07-16-221226-1465241-1 -x c ../src/basic/fs-util.c
1/* SPDX-License-Identifier: LGPL-2.1+ */
2
3#include <errno(*__errno_location ()).h>
4#include <stddef.h>
5#include <stdio.h>
6#include <stdlib.h>
7#include <string.h>
8#include <sys/stat.h>
9#include <linux1/magic.h>
10#include <time.h>
11#include <unistd.h>
12
13#include "alloc-util.h"
14#include "dirent-util.h"
15#include "fd-util.h"
16#include "fileio.h"
17#include "fs-util.h"
18#include "log.h"
19#include "macro.h"
20#include "missing.h"
21#include "mkdir.h"
22#include "parse-util.h"
23#include "path-util.h"
24#include "process-util.h"
25#include "stat-util.h"
26#include "stdio-util.h"
27#include "string-util.h"
28#include "strv.h"
29#include "time-util.h"
30#include "user-util.h"
31#include "util.h"
32
33int unlink_noerrno(const char *path) {
34 PROTECT_ERRNO__attribute__((cleanup(_reset_errno_))) __attribute__((unused
)) int _saved_errno_ = (*__errno_location ());
35 int r;
36
37 r = unlink(path);
38 if (r < 0)
39 return -errno(*__errno_location ());
40
41 return 0;
42}
43
44int rmdir_parents(const char *path, const char *stop) {
45 size_t l;
46 int r = 0;
47
48 assert(path)do { if ((__builtin_expect(!!(!(path)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("path"), "../src/basic/fs-util.c", 48, __PRETTY_FUNCTION__
); } while (0);
49 assert(stop)do { if ((__builtin_expect(!!(!(stop)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("stop"), "../src/basic/fs-util.c", 49, __PRETTY_FUNCTION__
); } while (0);
50
51 l = strlen(path);
52
53 /* Skip trailing slashes */
54 while (l > 0 && path[l-1] == '/')
55 l--;
56
57 while (l > 0) {
58 char *t;
59
60 /* Skip last component */
61 while (l > 0 && path[l-1] != '/')
62 l--;
63
64 /* Skip trailing slashes */
65 while (l > 0 && path[l-1] == '/')
66 l--;
67
68 if (l <= 0)
69 break;
70
71 t = strndup(path, l);
72 if (!t)
73 return -ENOMEM12;
74
75 if (path_startswith(stop, t)) {
76 free(t);
77 return 0;
78 }
79
80 r = rmdir(t);
81 free(t);
82
83 if (r < 0)
84 if (errno(*__errno_location ()) != ENOENT2)
85 return -errno(*__errno_location ());
86 }
87
88 return 0;
89}
90
91int rename_noreplace(int olddirfd, const char *oldpath, int newdirfd, const char *newpath) {
92 struct stat buf;
93 int ret;
94
95 ret = renameat2(olddirfd, oldpath, newdirfd, newpath, RENAME_NOREPLACE(1 << 0));
96 if (ret >= 0)
97 return 0;
98
99 /* renameat2() exists since Linux 3.15, btrfs added support for it later.
100 * If it is not implemented, fallback to another method. */
101 if (!IN_SET(errno, EINVAL, ENOSYS)({ _Bool _found = 0; static __attribute__ ((unused)) char _static_assert__macros_need_to_be_extended
[20 - sizeof((int[]){22, 38})/sizeof(int)]; switch((*__errno_location
())) { case 22: case 38: _found = 1; break; default: break; }
_found; }))
102 return -errno(*__errno_location ());
103
104 /* The link()/unlink() fallback does not work on directories. But
105 * renameat() without RENAME_NOREPLACE gives the same semantics on
106 * directories, except when newpath is an *empty* directory. This is
107 * good enough. */
108 ret = fstatat(olddirfd, oldpath, &buf, AT_SYMLINK_NOFOLLOW0x100);
109 if (ret >= 0 && S_ISDIR(buf.st_mode)((((buf.st_mode)) & 0170000) == (0040000))) {
110 ret = renameat(olddirfd, oldpath, newdirfd, newpath);
111 return ret >= 0 ? 0 : -errno(*__errno_location ());
112 }
113
114 /* If it is not a directory, use the link()/unlink() fallback. */
115 ret = linkat(olddirfd, oldpath, newdirfd, newpath, 0);
116 if (ret < 0)
117 return -errno(*__errno_location ());
118
119 ret = unlinkat(olddirfd, oldpath, 0);
120 if (ret < 0) {
121 /* backup errno before the following unlinkat() alters it */
122 ret = errno(*__errno_location ());
123 (void) unlinkat(newdirfd, newpath, 0);
124 errno(*__errno_location ()) = ret;
125 return -errno(*__errno_location ());
126 }
127
128 return 0;
129}
130
131int readlinkat_malloc(int fd, const char *p, char **ret) {
132 size_t l = 100;
133 int r;
134
135 assert(p)do { if ((__builtin_expect(!!(!(p)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("p"), "../src/basic/fs-util.c", 135, __PRETTY_FUNCTION__
); } while (0);
136 assert(ret)do { if ((__builtin_expect(!!(!(ret)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("ret"), "../src/basic/fs-util.c", 136, __PRETTY_FUNCTION__
); } while (0);
137
138 for (;;) {
139 char *c;
140 ssize_t n;
141
142 c = new(char, l)((char*) malloc_multiply(sizeof(char), (l)));
143 if (!c)
144 return -ENOMEM12;
145
146 n = readlinkat(fd, p, c, l-1);
147 if (n < 0) {
148 r = -errno(*__errno_location ());
149 free(c);
150 return r;
151 }
152
153 if ((size_t) n < l-1) {
154 c[n] = 0;
155 *ret = c;
156 return 0;
157 }
158
159 free(c);
160 l *= 2;
161 }
162}
163
164int readlink_malloc(const char *p, char **ret) {
165 return readlinkat_malloc(AT_FDCWD-100, p, ret);
166}
167
168int readlink_value(const char *p, char **ret) {
169 _cleanup_free___attribute__((cleanup(freep))) char *link = NULL((void*)0);
170 char *value;
171 int r;
172
173 r = readlink_malloc(p, &link);
174 if (r < 0)
175 return r;
176
177 value = basename(link);
178 if (!value)
179 return -ENOENT2;
180
181 value = strdup(value);
182 if (!value)
183 return -ENOMEM12;
184
185 *ret = value;
186
187 return 0;
188}
189
190int readlink_and_make_absolute(const char *p, char **r) {
191 _cleanup_free___attribute__((cleanup(freep))) char *target = NULL((void*)0);
192 char *k;
193 int j;
194
195 assert(p)do { if ((__builtin_expect(!!(!(p)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("p"), "../src/basic/fs-util.c", 195, __PRETTY_FUNCTION__
); } while (0);
196 assert(r)do { if ((__builtin_expect(!!(!(r)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("r"), "../src/basic/fs-util.c", 196, __PRETTY_FUNCTION__
); } while (0);
197
198 j = readlink_malloc(p, &target);
199 if (j < 0)
200 return j;
201
202 k = file_in_same_dir(p, target);
203 if (!k)
204 return -ENOMEM12;
205
206 *r = k;
207 return 0;
208}
209
210int chmod_and_chown(const char *path, mode_t mode, uid_t uid, gid_t gid) {
211 assert(path)do { if ((__builtin_expect(!!(!(path)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("path"), "../src/basic/fs-util.c", 211, __PRETTY_FUNCTION__
); } while (0);
212
213 /* Under the assumption that we are running privileged we
214 * first change the access mode and only then hand out
215 * ownership to avoid a window where access is too open. */
216
217 if (mode != MODE_INVALID((mode_t) -1))
218 if (chmod(path, mode) < 0)
219 return -errno(*__errno_location ());
220
221 if (uid != UID_INVALID((uid_t) -1) || gid != GID_INVALID((gid_t) -1))
222 if (chown(path, uid, gid) < 0)
223 return -errno(*__errno_location ());
224
225 return 0;
226}
227
228int fchmod_and_chown(int fd, mode_t mode, uid_t uid, gid_t gid) {
229 /* Under the assumption that we are running privileged we
230 * first change the access mode and only then hand out
231 * ownership to avoid a window where access is too open. */
232
233 if (mode != MODE_INVALID((mode_t) -1))
234 if (fchmod(fd, mode) < 0)
235 return -errno(*__errno_location ());
236
237 if (uid != UID_INVALID((uid_t) -1) || gid != GID_INVALID((gid_t) -1))
238 if (fchown(fd, uid, gid) < 0)
239 return -errno(*__errno_location ());
240
241 return 0;
242}
243
244int fchmod_umask(int fd, mode_t m) {
245 mode_t u;
246 int r;
247
248 u = umask(0777);
249 r = fchmod(fd, m & (~u)) < 0 ? -errno(*__errno_location ()) : 0;
250 umask(u);
251
252 return r;
253}
254
255int fchmod_opath(int fd, mode_t m) {
256 char procfs_path[STRLEN("/proc/self/fd/")(sizeof("""/proc/self/fd/""") - 1) + DECIMAL_STR_MAX(int)(2+(sizeof(int) <= 1 ? 3 : sizeof(int) <= 2 ? 5 : sizeof
(int) <= 4 ? 10 : sizeof(int) <= 8 ? 20 : sizeof(int[-2
*(sizeof(int) > 8)])))];
257
258 /* This function operates also on fd that might have been opened with
259 * O_PATH. Indeed fchmodat() doesn't have the AT_EMPTY_PATH flag like
260 * fchownat() does. */
261
262 xsprintf(procfs_path, "/proc/self/fd/%i", fd)do { if ((__builtin_expect(!!(!(((size_t) snprintf(procfs_path
, __extension__ (__builtin_choose_expr( !__builtin_types_compatible_p
(typeof(procfs_path), typeof(&*(procfs_path))), sizeof(procfs_path
)/sizeof((procfs_path)[0]), ((void)0))), "/proc/self/fd/%i", fd
) < (__extension__ (__builtin_choose_expr( !__builtin_types_compatible_p
(typeof(procfs_path), typeof(&*(procfs_path))), sizeof(procfs_path
)/sizeof((procfs_path)[0]), ((void)0))))))),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("xsprintf: " "procfs_path" "[] must be big enough"
), "../src/basic/fs-util.c", 262, __PRETTY_FUNCTION__); } while
(0);
263
264 if (chmod(procfs_path, m) < 0)
265 return -errno(*__errno_location ());
266
267 return 0;
268}
269
270int fd_warn_permissions(const char *path, int fd) {
271 struct stat st;
272
273 if (fstat(fd, &st) < 0)
274 return -errno(*__errno_location ());
275
276 if (st.st_mode & 0111)
277 log_warning("Configuration file %s is marked executable. Please remove executable permission bits. Proceeding anyway.", path)({ int _level = (((4))), _e = ((0)), _realm = (LOG_REALM_SYSTEMD
); (log_get_max_level_realm(_realm) >= ((_level) & 0x07
)) ? log_internal_realm(((_realm) << 10 | (_level)), _e
, "../src/basic/fs-util.c", 277, __func__, "Configuration file %s is marked executable. Please remove executable permission bits. Proceeding anyway."
, path) : -abs(_e); });
278
279 if (st.st_mode & 0002)
280 log_warning("Configuration file %s is marked world-writable. Please remove world writability permission bits. Proceeding anyway.", path)({ int _level = (((4))), _e = ((0)), _realm = (LOG_REALM_SYSTEMD
); (log_get_max_level_realm(_realm) >= ((_level) & 0x07
)) ? log_internal_realm(((_realm) << 10 | (_level)), _e
, "../src/basic/fs-util.c", 280, __func__, "Configuration file %s is marked world-writable. Please remove world writability permission bits. Proceeding anyway."
, path) : -abs(_e); });
281
282 if (getpid_cached() == 1 && (st.st_mode & 0044) != 0044)
283 log_warning("Configuration file %s is marked world-inaccessible. This has no effect as configuration data is accessible via APIs without restrictions. Proceeding anyway.", path)({ int _level = (((4))), _e = ((0)), _realm = (LOG_REALM_SYSTEMD
); (log_get_max_level_realm(_realm) >= ((_level) & 0x07
)) ? log_internal_realm(((_realm) << 10 | (_level)), _e
, "../src/basic/fs-util.c", 283, __func__, "Configuration file %s is marked world-inaccessible. This has no effect as configuration data is accessible via APIs without restrictions. Proceeding anyway."
, path) : -abs(_e); });
284
285 return 0;
286}
287
288int touch_file(const char *path, bool_Bool parents, usec_t stamp, uid_t uid, gid_t gid, mode_t mode) {
289 char fdpath[STRLEN("/proc/self/fd/")(sizeof("""/proc/self/fd/""") - 1) + DECIMAL_STR_MAX(int)(2+(sizeof(int) <= 1 ? 3 : sizeof(int) <= 2 ? 5 : sizeof
(int) <= 4 ? 10 : sizeof(int) <= 8 ? 20 : sizeof(int[-2
*(sizeof(int) > 8)])))];
290 _cleanup_close___attribute__((cleanup(closep))) int fd = -1;
291 int r, ret = 0;
292
293 assert(path)do { if ((__builtin_expect(!!(!(path)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("path"), "../src/basic/fs-util.c", 293, __PRETTY_FUNCTION__
); } while (0);
294
295 /* Note that touch_file() does not follow symlinks: if invoked on an existing symlink, then it is the symlink
296 * itself which is updated, not its target
297 *
298 * Returns the first error we encounter, but tries to apply as much as possible. */
299
300 if (parents)
301 (void) mkdir_parents(path, 0755);
302
303 /* Initially, we try to open the node with O_PATH, so that we get a reference to the node. This is useful in
304 * case the path refers to an existing device or socket node, as we can open it successfully in all cases, and
305 * won't trigger any driver magic or so. */
306 fd = open(path, O_PATH010000000|O_CLOEXEC02000000|O_NOFOLLOW0400000);
307 if (fd < 0) {
308 if (errno(*__errno_location ()) != ENOENT2)
309 return -errno(*__errno_location ());
310
311 /* if the node doesn't exist yet, we create it, but with O_EXCL, so that we only create a regular file
312 * here, and nothing else */
313 fd = open(path, O_WRONLY01|O_CREAT0100|O_EXCL0200|O_CLOEXEC02000000, IN_SET(mode, 0, MODE_INVALID)({ _Bool _found = 0; static __attribute__ ((unused)) char _static_assert__macros_need_to_be_extended
[20 - sizeof((int[]){0, ((mode_t) -1)})/sizeof(int)]; switch(
mode) { case 0: case ((mode_t) -1): _found = 1; break; default
: break; } _found; }) ? 0644 : mode);
314 if (fd < 0)
315 return -errno(*__errno_location ());
316 }
317
318 /* Let's make a path from the fd, and operate on that. With this logic, we can adjust the access mode,
319 * ownership and time of the file node in all cases, even if the fd refers to an O_PATH object — which is
320 * something fchown(), fchmod(), futimensat() don't allow. */
321 xsprintf(fdpath, "/proc/self/fd/%i", fd)do { if ((__builtin_expect(!!(!(((size_t) snprintf(fdpath, __extension__
(__builtin_choose_expr( !__builtin_types_compatible_p(typeof
(fdpath), typeof(&*(fdpath))), sizeof(fdpath)/sizeof((fdpath
)[0]), ((void)0))), "/proc/self/fd/%i", fd) < (__extension__
(__builtin_choose_expr( !__builtin_types_compatible_p(typeof
(fdpath), typeof(&*(fdpath))), sizeof(fdpath)/sizeof((fdpath
)[0]), ((void)0))))))),0))) log_assert_failed_realm(LOG_REALM_SYSTEMD
, ("xsprintf: " "fdpath" "[] must be big enough"), "../src/basic/fs-util.c"
, 321, __PRETTY_FUNCTION__); } while (0);
322
323 if (mode != MODE_INVALID((mode_t) -1))
324 if (chmod(fdpath, mode) < 0)
325 ret = -errno(*__errno_location ());
326
327 if (uid_is_valid(uid) || gid_is_valid(gid))
328 if (chown(fdpath, uid, gid) < 0 && ret >= 0)
329 ret = -errno(*__errno_location ());
330
331 if (stamp != USEC_INFINITY((usec_t) -1)) {
332 struct timespec ts[2];
333
334 timespec_store(&ts[0], stamp);
335 ts[1] = ts[0];
336 r = utimensat(AT_FDCWD-100, fdpath, ts, 0);
337 } else
338 r = utimensat(AT_FDCWD-100, fdpath, NULL((void*)0), 0);
339 if (r < 0 && ret >= 0)
340 return -errno(*__errno_location ());
341
342 return ret;
343}
344
345int touch(const char *path) {
346 return touch_file(path, false0, USEC_INFINITY((usec_t) -1), UID_INVALID((uid_t) -1), GID_INVALID((gid_t) -1), MODE_INVALID((mode_t) -1));
347}
348
349int symlink_idempotent(const char *from, const char *to) {
350 int r;
351
352 assert(from)do { if ((__builtin_expect(!!(!(from)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("from"), "../src/basic/fs-util.c", 352, __PRETTY_FUNCTION__
); } while (0);
353 assert(to)do { if ((__builtin_expect(!!(!(to)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("to"), "../src/basic/fs-util.c", 353, __PRETTY_FUNCTION__
); } while (0);
354
355 if (symlink(from, to) < 0) {
356 _cleanup_free___attribute__((cleanup(freep))) char *p = NULL((void*)0);
357
358 if (errno(*__errno_location ()) != EEXIST17)
359 return -errno(*__errno_location ());
360
361 r = readlink_malloc(to, &p);
362 if (r == -EINVAL22) /* Not a symlink? In that case return the original error we encountered: -EEXIST */
363 return -EEXIST17;
364 if (r < 0) /* Any other error? In that case propagate it as is */
365 return r;
366
367 if (!streq(p, from)(strcmp((p),(from)) == 0)) /* Not the symlink we want it to be? In that case, propagate the original -EEXIST */
368 return -EEXIST17;
369 }
370
371 return 0;
372}
373
374int symlink_atomic(const char *from, const char *to) {
375 _cleanup_free___attribute__((cleanup(freep))) char *t = NULL((void*)0);
376 int r;
377
378 assert(from)do { if ((__builtin_expect(!!(!(from)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("from"), "../src/basic/fs-util.c", 378, __PRETTY_FUNCTION__
); } while (0);
379 assert(to)do { if ((__builtin_expect(!!(!(to)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("to"), "../src/basic/fs-util.c", 379, __PRETTY_FUNCTION__
); } while (0);
380
381 r = tempfn_random(to, NULL((void*)0), &t);
382 if (r < 0)
383 return r;
384
385 if (symlink(from, t) < 0)
386 return -errno(*__errno_location ());
387
388 if (rename(t, to) < 0) {
389 unlink_noerrno(t);
390 return -errno(*__errno_location ());
391 }
392
393 return 0;
394}
395
396int mknod_atomic(const char *path, mode_t mode, dev_t dev) {
397 _cleanup_free___attribute__((cleanup(freep))) char *t = NULL((void*)0);
398 int r;
399
400 assert(path)do { if ((__builtin_expect(!!(!(path)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("path"), "../src/basic/fs-util.c", 400, __PRETTY_FUNCTION__
); } while (0);
401
402 r = tempfn_random(path, NULL((void*)0), &t);
403 if (r < 0)
404 return r;
405
406 if (mknod(t, mode, dev) < 0)
407 return -errno(*__errno_location ());
408
409 if (rename(t, path) < 0) {
410 unlink_noerrno(t);
411 return -errno(*__errno_location ());
412 }
413
414 return 0;
415}
416
417int mkfifo_atomic(const char *path, mode_t mode) {
418 _cleanup_free___attribute__((cleanup(freep))) char *t = NULL((void*)0);
419 int r;
420
421 assert(path)do { if ((__builtin_expect(!!(!(path)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("path"), "../src/basic/fs-util.c", 421, __PRETTY_FUNCTION__
); } while (0);
422
423 r = tempfn_random(path, NULL((void*)0), &t);
424 if (r < 0)
425 return r;
426
427 if (mkfifo(t, mode) < 0)
428 return -errno(*__errno_location ());
429
430 if (rename(t, path) < 0) {
431 unlink_noerrno(t);
432 return -errno(*__errno_location ());
433 }
434
435 return 0;
436}
437
438int get_files_in_directory(const char *path, char ***list) {
439 _cleanup_closedir___attribute__((cleanup(closedirp))) DIR *d = NULL((void*)0);
440 struct dirent *de;
441 size_t bufsize = 0, n = 0;
442 _cleanup_strv_free___attribute__((cleanup(strv_freep))) char **l = NULL((void*)0);
443
444 assert(path)do { if ((__builtin_expect(!!(!(path)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("path"), "../src/basic/fs-util.c", 444, __PRETTY_FUNCTION__
); } while (0);
445
446 /* Returns all files in a directory in *list, and the number
447 * of files as return value. If list is NULL returns only the
448 * number. */
449
450 d = opendir(path);
451 if (!d)
452 return -errno(*__errno_location ());
453
454 FOREACH_DIRENT_ALL(de, d, return -errno)for ((*__errno_location ()) = 0, de = readdir(d);; (*__errno_location
()) = 0, de = readdir(d)) if (!de) { if ((*__errno_location (
)) > 0) { return -(*__errno_location ()); } break; } else {
455 dirent_ensure_type(d, de);
456
457 if (!dirent_is_file(de))
458 continue;
459
460 if (list) {
461 /* one extra slot is needed for the terminating NULL */
462 if (!GREEDY_REALLOC(l, bufsize, n + 2)greedy_realloc((void**) &(l), &(bufsize), (n + 2), sizeof
((l)[0])))
463 return -ENOMEM12;
464
465 l[n] = strdup(de->d_name);
466 if (!l[n])
467 return -ENOMEM12;
468
469 l[++n] = NULL((void*)0);
470 } else
471 n++;
472 }
473
474 if (list)
475 *list = TAKE_PTR(l)({ typeof(l) _ptr_ = (l); (l) = ((void*)0); _ptr_; });
476
477 return n;
478}
479
480static int getenv_tmp_dir(const char **ret_path) {
481 const char *n;
482 int r, ret = 0;
483
484 assert(ret_path)do { if ((__builtin_expect(!!(!(ret_path)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("ret_path"), "../src/basic/fs-util.c", 484
, __PRETTY_FUNCTION__); } while (0);
485
486 /* We use the same order of environment variables python uses in tempfile.gettempdir():
487 * https://docs.python.org/3/library/tempfile.html#tempfile.gettempdir */
488 FOREACH_STRING(n, "TMPDIR", "TEMP", "TMP")for (char **_l = ({ char **_ll = ((char**) ((const char*[]) {
"TMPDIR", "TEMP", "TMP", ((void*)0) })); n = _ll ? _ll[0] : (
(void*)0); _ll; }); _l && *_l; n = ({ _l ++; _l[0]; }
)) {
489 const char *e;
490
491 e = secure_getenv(n);
492 if (!e)
493 continue;
494 if (!path_is_absolute(e)) {
495 r = -ENOTDIR20;
496 goto next;
497 }
498 if (!path_is_normalized(e)) {
499 r = -EPERM1;
500 goto next;
501 }
502
503 r = is_dir(e, true1);
504 if (r < 0)
505 goto next;
506 if (r == 0) {
507 r = -ENOTDIR20;
508 goto next;
509 }
510
511 *ret_path = e;
512 return 1;
513
514 next:
515 /* Remember first error, to make this more debuggable */
516 if (ret >= 0)
517 ret = r;
518 }
519
520 if (ret < 0)
521 return ret;
522
523 *ret_path = NULL((void*)0);
524 return ret;
525}
526
527static int tmp_dir_internal(const char *def, const char **ret) {
528 const char *e;
529 int r, k;
530
531 assert(def)do { if ((__builtin_expect(!!(!(def)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("def"), "../src/basic/fs-util.c", 531, __PRETTY_FUNCTION__
); } while (0);
532 assert(ret)do { if ((__builtin_expect(!!(!(ret)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("ret"), "../src/basic/fs-util.c", 532, __PRETTY_FUNCTION__
); } while (0);
533
534 r = getenv_tmp_dir(&e);
535 if (r > 0) {
536 *ret = e;
537 return 0;
538 }
539
540 k = is_dir(def, true1);
541 if (k == 0)
542 k = -ENOTDIR20;
543 if (k < 0)
544 return r < 0 ? r : k;
545
546 *ret = def;
547 return 0;
548}
549
550int var_tmp_dir(const char **ret) {
551
552 /* Returns the location for "larger" temporary files, that is backed by physical storage if available, and thus
553 * even might survive a boot: /var/tmp. If $TMPDIR (or related environment variables) are set, its value is
554 * returned preferably however. Note that both this function and tmp_dir() below are affected by $TMPDIR,
555 * making it a variable that overrides all temporary file storage locations. */
556
557 return tmp_dir_internal("/var/tmp", ret);
558}
559
560int tmp_dir(const char **ret) {
561
562 /* Similar to var_tmp_dir() above, but returns the location for "smaller" temporary files, which is usually
563 * backed by an in-memory file system: /tmp. */
564
565 return tmp_dir_internal("/tmp", ret);
566}
567
568int unlink_or_warn(const char *filename) {
569 if (unlink(filename) < 0 && errno(*__errno_location ()) != ENOENT2)
570 /* If the file doesn't exist and the fs simply was read-only (in which
571 * case unlink() returns EROFS even if the file doesn't exist), don't
572 * complain */
573 if (errno(*__errno_location ()) != EROFS30 || access(filename, F_OK0) >= 0)
574 return log_error_errno(errno, "Failed to remove \"%s\": %m", filename)({ int _level = ((3)), _e = (((*__errno_location ()))), _realm
= (LOG_REALM_SYSTEMD); (log_get_max_level_realm(_realm) >=
((_level) & 0x07)) ? log_internal_realm(((_realm) <<
10 | (_level)), _e, "../src/basic/fs-util.c", 574, __func__,
"Failed to remove \"%s\": %m", filename) : -abs(_e); });
575
576 return 0;
577}
578
579int inotify_add_watch_fd(int fd, int what, uint32_t mask) {
580 char path[STRLEN("/proc/self/fd/")(sizeof("""/proc/self/fd/""") - 1) + DECIMAL_STR_MAX(int)(2+(sizeof(int) <= 1 ? 3 : sizeof(int) <= 2 ? 5 : sizeof
(int) <= 4 ? 10 : sizeof(int) <= 8 ? 20 : sizeof(int[-2
*(sizeof(int) > 8)]))) + 1];
581 int r;
582
583 /* This is like inotify_add_watch(), except that the file to watch is not referenced by a path, but by an fd */
584 xsprintf(path, "/proc/self/fd/%i", what)do { if ((__builtin_expect(!!(!(((size_t) snprintf(path, __extension__
(__builtin_choose_expr( !__builtin_types_compatible_p(typeof
(path), typeof(&*(path))), sizeof(path)/sizeof((path)[0])
, ((void)0))), "/proc/self/fd/%i", what) < (__extension__ (
__builtin_choose_expr( !__builtin_types_compatible_p(typeof(path
), typeof(&*(path))), sizeof(path)/sizeof((path)[0]), ((void
)0))))))),0))) log_assert_failed_realm(LOG_REALM_SYSTEMD, ("xsprintf: "
"path" "[] must be big enough"), "../src/basic/fs-util.c", 584
, __PRETTY_FUNCTION__); } while (0);
585
586 r = inotify_add_watch(fd, path, mask);
587 if (r < 0)
588 return -errno(*__errno_location ());
589
590 return r;
591}
592
593static bool_Bool safe_transition(const struct stat *a, const struct stat *b) {
594 /* Returns true if the transition from a to b is safe, i.e. that we never transition from unprivileged to
595 * privileged files or directories. Why bother? So that unprivileged code can't symlink to privileged files
596 * making us believe we read something safe even though it isn't safe in the specific context we open it in. */
597
598 if (a->st_uid == 0) /* Transitioning from privileged to unprivileged is always fine */
599 return true1;
600
601 return a->st_uid == b->st_uid; /* Otherwise we need to stay within the same UID */
602}
603
604int chase_symlinks(const char *path, const char *original_root, unsigned flags, char **ret) {
605 _cleanup_free___attribute__((cleanup(freep))) char *buffer = NULL((void*)0), *done = NULL((void*)0), *root = NULL((void*)0);
606 _cleanup_close___attribute__((cleanup(closep))) int fd = -1;
607 unsigned max_follow = CHASE_SYMLINKS_MAX32; /* how many symlinks to follow before giving up and returning ELOOP */
608 struct stat previous_stat;
609 bool_Bool exists = true1;
610 char *todo;
611 int r;
612
613 assert(path)do { if ((__builtin_expect(!!(!(path)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("path"), "../src/basic/fs-util.c", 613, __PRETTY_FUNCTION__
); } while (0);
1
Assuming 'path' is non-null
→
2
←
Taking false branch
→
3
←
Loop condition is false. Exiting loop
→
614
615 /* Either the file may be missing, or we return an fd to the final object, but both make no sense */
616 if (FLAGS_SET(flags, CHASE_NONEXISTENT | CHASE_OPEN)(((flags) & (CHASE_NONEXISTENT | CHASE_OPEN)) == (CHASE_NONEXISTENT
| CHASE_OPEN)))
4
←
Assuming the condition is false
→
5
←
Taking false branch
→
617 return -EINVAL22;
618
619 if (FLAGS_SET(flags, CHASE_STEP | CHASE_OPEN)(((flags) & (CHASE_STEP | CHASE_OPEN)) == (CHASE_STEP | CHASE_OPEN
)))
6
←
Assuming the condition is false
→
7
←
Taking false branch
→
620 return -EINVAL22;
621
622 if (isempty(path))
8
←
Taking false branch
→
623 return -EINVAL22;
624
625 /* This is a lot like canonicalize_file_name(), but takes an additional "root" parameter, that allows following
626 * symlinks relative to a root directory, instead of the root of the host.
627 *
628 * Note that "root" primarily matters if we encounter an absolute symlink. It is also used when following
629 * relative symlinks to ensure they cannot be used to "escape" the root directory. The path parameter passed is
630 * assumed to be already prefixed by it, except if the CHASE_PREFIX_ROOT flag is set, in which case it is first
631 * prefixed accordingly.
632 *
633 * Algorithmically this operates on two path buffers: "done" are the components of the path we already
634 * processed and resolved symlinks, "." and ".." of. "todo" are the components of the path we still need to
635 * process. On each iteration, we move one component from "todo" to "done", processing it's special meaning
636 * each time. The "todo" path always starts with at least one slash, the "done" path always ends in no
637 * slash. We always keep an O_PATH fd to the component we are currently processing, thus keeping lookup races
638 * at a minimum.
639 *
640 * Suggested usage: whenever you want to canonicalize a path, use this function. Pass the absolute path you got
641 * as-is: fully qualified and relative to your host's root. Optionally, specify the root parameter to tell this
642 * function what to do when encountering a symlink with an absolute path as directory: prefix it by the
643 * specified path.
644 *
645 * There are three ways to invoke this function:
646 *
647 * 1. Without CHASE_STEP or CHASE_OPEN: in this case the path is resolved and the normalized path is returned
648 * in `ret`. The return value is < 0 on error. If CHASE_NONEXISTENT is also set 0 is returned if the file
649 * doesn't exist, > 0 otherwise. If CHASE_NONEXISTENT is not set >= 0 is returned if the destination was
650 * found, -ENOENT if it doesn't.
651 *
652 * 2. With CHASE_OPEN: in this case the destination is opened after chasing it as O_PATH and this file
653 * descriptor is returned as return value. This is useful to open files relative to some root
654 * directory. Note that the returned O_PATH file descriptors must be converted into a regular one (using
655 * fd_reopen() or such) before it can be used for reading/writing. CHASE_OPEN may not be combined with
656 * CHASE_NONEXISTENT.
657 *
658 * 3. With CHASE_STEP: in this case only a single step of the normalization is executed, i.e. only the first
659 * symlink or ".." component of the path is resolved, and the resulting path is returned. This is useful if
660 * a caller wants to trace the a path through the file system verbosely. Returns < 0 on error, > 0 if the
661 * path is fully normalized, and == 0 for each normalization step. This may be combined with
662 * CHASE_NONEXISTENT, in which case 1 is returned when a component is not found.
663 *
664 * */
665
666 /* A root directory of "/" or "" is identical to none */
667 if (empty_or_root(original_root))
9
←
Assuming the condition is false
→
10
←
Taking false branch
→
668 original_root = NULL((void*)0);
669
670 if (!original_root && !ret && (flags & (CHASE_NONEXISTENT|CHASE_NO_AUTOFS|CHASE_SAFE|CHASE_OPEN|CHASE_STEP)) == CHASE_OPEN) {
11
←
Assuming 'original_root' is null
→
12
←
Assuming 'ret' is null
→
13
←
Assuming the condition is false
→
14
←
Taking false branch
→
671 /* Shortcut the CHASE_OPEN case if the caller isn't interested in the actual path and has no root set
672 * and doesn't care about any of the other special features we provide either. */
673 r = open(path, O_PATH010000000|O_CLOEXEC02000000);
674 if (r < 0)
675 return -errno(*__errno_location ());
676
677 return r;
678 }
679
680 if (original_root
14.1
'original_root' is null
) {
15
←
Taking false branch
→
681 r = path_make_absolute_cwd(original_root, &root);
682 if (r < 0)
683 return r;
684
685 if (flags & CHASE_PREFIX_ROOT) {
686
687 /* We don't support relative paths in combination with a root directory */
688 if (!path_is_absolute(path))
689 return -EINVAL22;
690
691 path = prefix_roota(root, path)({ const char* _path = (path), *_root = (root), *_ret; char *
_p, *_n; size_t _l; while (_path[0] == '/' && _path[1
] == '/') _path ++; if (empty_or_root(_root)) _ret = _path; else
{ _l = strlen(_root) + 1 + strlen(_path) + 1; _n = __builtin_alloca
(_l); _p = stpcpy(_n, _root); while (_p > _n && _p
[-1] == '/') _p--; if (_path[0] != '/') *(_p++) = '/'; strcpy
(_p, _path); _ret = _n; } _ret; });
692 }
693 }
694
695 r = path_make_absolute_cwd(path, &buffer);
696 if (r < 0)
16
←
Assuming 'r' is >= 0
→
17
←
Taking false branch
→
697 return r;
698
699 fd = open("/", O_CLOEXEC02000000|O_NOFOLLOW0400000|O_PATH010000000);
700 if (fd < 0)
18
←
Assuming 'fd' is >= 0
→
19
←
Taking false branch
→
701 return -errno(*__errno_location ());
702
703 if (flags & CHASE_SAFE) {
20
←
Assuming the condition is false
→
21
←
Taking false branch
→
704 if (fstat(fd, &previous_stat) < 0)
705 return -errno(*__errno_location ());
706 }
707
708 todo = buffer;
709 for (;;) {
22
←
Loop condition is true. Entering loop body
→
710 _cleanup_free___attribute__((cleanup(freep))) char *first = NULL((void*)0);
711 _cleanup_close___attribute__((cleanup(closep))) int child = -1;
712 struct stat st;
713 size_t n, m;
714
715 /* Determine length of first component in the path */
716 n = strspn(todo, "/"); /* The slashes */
717 m = n + strcspn(todo + n, "/"); /* The entire length of the component */
718
719 /* Extract the first component. */
720 first = strndup(todo, m);
721 if (!first)
23
←
Assuming 'first' is non-null
→
24
←
Taking false branch
→
722 return -ENOMEM12;
723
724 todo += m;
725
726 /* Empty? Then we reached the end. */
727 if (isempty(first))
25
←
Taking true branch
→
728 break;
26
←
 Execution continues on line 909
→
729
730 /* Just a single slash? Then we reached the end. */
731 if (path_equal(first, "/")) {
732 /* Preserve the trailing slash */
733
734 if (flags & CHASE_TRAIL_SLASH)
735 if (!strextend(&done, "/", NULL)strextend_with_separator(&done, ((void*)0), "/", ((void*)
0)))
736 return -ENOMEM12;
737
738 break;
739 }
740
741 /* Just a dot? Then let's eat this up. */
742 if (path_equal(first, "/."))
743 continue;
744
745 /* Two dots? Then chop off the last bit of what we already found out. */
746 if (path_equal(first, "/..")) {
747 _cleanup_free___attribute__((cleanup(freep))) char *parent = NULL((void*)0);
748 _cleanup_close___attribute__((cleanup(closep))) int fd_parent = -1;
749
750 /* If we already are at the top, then going up will not change anything. This is in-line with
751 * how the kernel handles this. */
752 if (empty_or_root(done))
753 continue;
754
755 parent = dirname_malloc(done);
756 if (!parent)
757 return -ENOMEM12;
758
759 /* Don't allow this to leave the root dir. */
760 if (root &&
761 path_startswith(done, root) &&
762 !path_startswith(parent, root))
763 continue;
764
765 free_and_replace(done, parent)({ free(done); (done) = (parent); (parent) = ((void*)0); 0; }
);
766
767 if (flags & CHASE_STEP)
768 goto chased_one;
769
770 fd_parent = openat(fd, "..", O_CLOEXEC02000000|O_NOFOLLOW0400000|O_PATH010000000);
771 if (fd_parent < 0)
772 return -errno(*__errno_location ());
773
774 if (flags & CHASE_SAFE) {
775 if (fstat(fd_parent, &st) < 0)
776 return -errno(*__errno_location ());
777
778 if (!safe_transition(&previous_stat, &st))
779 return -EPERM1;
780
781 previous_stat = st;
782 }
783
784 safe_close(fd);
785 fd = TAKE_FD(fd_parent)({ int _fd_ = (fd_parent); (fd_parent) = -1; _fd_; });
786
787 continue;
788 }
789
790 /* Otherwise let's see what this is. */
791 child = openat(fd, first + n, O_CLOEXEC02000000|O_NOFOLLOW0400000|O_PATH010000000);
792 if (child < 0) {
793
794 if (errno(*__errno_location ()) == ENOENT2 &&
795 (flags & CHASE_NONEXISTENT) &&
796 (isempty(todo) || path_is_normalized(todo))) {
797
798 /* If CHASE_NONEXISTENT is set, and the path does not exist, then that's OK, return
799 * what we got so far. But don't allow this if the remaining path contains "../ or "./"
800 * or something else weird. */
801
802 /* If done is "/", as first also contains slash at the head, then remove this redundant slash. */
803 if (streq_ptr(done, "/"))
804 *done = '\0';
805
806 if (!strextend(&done, first, todo, NULL)strextend_with_separator(&done, ((void*)0), first, todo, (
(void*)0)))
807 return -ENOMEM12;
808
809 exists = false0;
810 break;
811 }
812
813 return -errno(*__errno_location ());
814 }
815
816 if (fstat(child, &st) < 0)
817 return -errno(*__errno_location ());
818 if ((flags & CHASE_SAFE) &&
819 !safe_transition(&previous_stat, &st))
820 return -EPERM1;
821
822 previous_stat = st;
823
824 if ((flags & CHASE_NO_AUTOFS) &&
825 fd_is_fs_type(child, AUTOFS_SUPER_MAGIC0x0187) > 0)
826 return -EREMOTE66;
827
828 if (S_ISLNK(st.st_mode)((((st.st_mode)) & 0170000) == (0120000))) {
829 char *joined;
830
831 _cleanup_free___attribute__((cleanup(freep))) char *destination = NULL((void*)0);
832
833 /* This is a symlink, in this case read the destination. But let's make sure we don't follow
834 * symlinks without bounds. */
835 if (--max_follow <= 0)
836 return -ELOOP40;
837
838 r = readlinkat_malloc(fd, first + n, &destination);
839 if (r < 0)
840 return r;
841 if (isempty(destination))
842 return -EINVAL22;
843
844 if (path_is_absolute(destination)) {
845
846 /* An absolute destination. Start the loop from the beginning, but use the root
847 * directory as base. */
848
849 safe_close(fd);
850 fd = open(root ?: "/", O_CLOEXEC02000000|O_NOFOLLOW0400000|O_PATH010000000);
851 if (fd < 0)
852 return -errno(*__errno_location ());
853
854 if (flags & CHASE_SAFE) {
855 if (fstat(fd, &st) < 0)
856 return -errno(*__errno_location ());
857
858 if (!safe_transition(&previous_stat, &st))
859 return -EPERM1;
860
861 previous_stat = st;
862 }
863
864 free(done);
865
866 /* Note that we do not revalidate the root, we take it as is. */
867 if (isempty(root))
868 done = NULL((void*)0);
869 else {
870 done = strdup(root);
871 if (!done)
872 return -ENOMEM12;
873 }
874
875 /* Prefix what's left to do with what we just read, and start the loop again, but
876 * remain in the current directory. */
877 joined = strjoin(destination, todo)strjoin_real((destination), todo, ((void*)0));
878 } else
879 joined = strjoin("/", destination, todo)strjoin_real(("/"), destination, todo, ((void*)0));
880 if (!joined)
881 return -ENOMEM12;
882
883 free(buffer);
884 todo = buffer = joined;
885
886 if (flags & CHASE_STEP)
887 goto chased_one;
888
889 continue;
890 }
891
892 /* If this is not a symlink, then let's just add the name we read to what we already verified. */
893 if (!done)
894 done = TAKE_PTR(first)({ typeof(first) _ptr_ = (first); (first) = ((void*)0); _ptr_
; });
895 else {
896 /* If done is "/", as first also contains slash at the head, then remove this redundant slash. */
897 if (streq(done, "/")(strcmp((done),("/")) == 0))
898 *done = '\0';
899
900 if (!strextend(&done, first, NULL)strextend_with_separator(&done, ((void*)0), first, ((void
*)0)))
901 return -ENOMEM12;
902 }
903
904 /* And iterate again, but go one directory further down. */
905 safe_close(fd);
906 fd = TAKE_FD(child)({ int _fd_ = (child); (child) = -1; _fd_; });
907 }
908
909 if (!done
26.1
'done' is null
) {
27
←
Taking true branch
→
910 /* Special case, turn the empty string into "/", to indicate the root directory. */
911 done = strdup("/");
28
←
Memory is allocated
→
912 if (!done)
29
←
Assuming 'done' is non-null
→
30
←
Taking false branch
→
913 return -ENOMEM12;
914 }
915
916 if (ret
30.1
'ret' is null
)
31
←
Taking false branch
→
917 *ret = TAKE_PTR(done)({ typeof(done) _ptr_ = (done); (done) = ((void*)0); _ptr_; }
);
918
919 if (flags & CHASE_OPEN) {
32
←
Potential leak of memory pointed to by 'done'
920 /* Return the O_PATH fd we currently are looking to the caller. It can translate it to a proper fd by
921 * opening /proc/self/fd/xyz. */
922
923 assert(fd >= 0)do { if ((__builtin_expect(!!(!(fd >= 0)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("fd >= 0"), "../src/basic/fs-util.c",
923, __PRETTY_FUNCTION__); } while (0);
924 return TAKE_FD(fd)({ int _fd_ = (fd); (fd) = -1; _fd_; });
925 }
926
927 if (flags & CHASE_STEP)
928 return 1;
929
930 return exists;
931
932chased_one:
933 if (ret) {
934 char *c;
935
936 c = strjoin(strempty(done), todo)strjoin_real((strempty(done)), todo, ((void*)0));
937 if (!c)
938 return -ENOMEM12;
939
940 *ret = c;
941 }
942
943 return 0;
944}
945
946int chase_symlinks_and_open(
947 const char *path,
948 const char *root,
949 unsigned chase_flags,
950 int open_flags,
951 char **ret_path) {
952
953 _cleanup_close___attribute__((cleanup(closep))) int path_fd = -1;
954 _cleanup_free___attribute__((cleanup(freep))) char *p = NULL((void*)0);
955 int r;
956
957 if (chase_flags & CHASE_NONEXISTENT)
958 return -EINVAL22;
959
960 if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) {
961 /* Shortcut this call if none of the special features of this call are requested */
962 r = open(path, open_flags);
963 if (r < 0)
964 return -errno(*__errno_location ());
965
966 return r;
967 }
968
969 path_fd = chase_symlinks(path, root, chase_flags|CHASE_OPEN, ret_path ? &p : NULL((void*)0));
970 if (path_fd < 0)
971 return path_fd;
972
973 r = fd_reopen(path_fd, open_flags);
974 if (r < 0)
975 return r;
976
977 if (ret_path)
978 *ret_path = TAKE_PTR(p)({ typeof(p) _ptr_ = (p); (p) = ((void*)0); _ptr_; });
979
980 return r;
981}
982
983int chase_symlinks_and_opendir(
984 const char *path,
985 const char *root,
986 unsigned chase_flags,
987 char **ret_path,
988 DIR **ret_dir) {
989
990 char procfs_path[STRLEN("/proc/self/fd/")(sizeof("""/proc/self/fd/""") - 1) + DECIMAL_STR_MAX(int)(2+(sizeof(int) <= 1 ? 3 : sizeof(int) <= 2 ? 5 : sizeof
(int) <= 4 ? 10 : sizeof(int) <= 8 ? 20 : sizeof(int[-2
*(sizeof(int) > 8)])))];
991 _cleanup_close___attribute__((cleanup(closep))) int path_fd = -1;
992 _cleanup_free___attribute__((cleanup(freep))) char *p = NULL((void*)0);
993 DIR *d;
994
995 if (!ret_dir)
996 return -EINVAL22;
997 if (chase_flags & CHASE_NONEXISTENT)
998 return -EINVAL22;
999
1000 if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) {
1001 /* Shortcut this call if none of the special features of this call are requested */
1002 d = opendir(path);
1003 if (!d)
1004 return -errno(*__errno_location ());
1005
1006 *ret_dir = d;
1007 return 0;
1008 }
1009
1010 path_fd = chase_symlinks(path, root, chase_flags|CHASE_OPEN, ret_path ? &p : NULL((void*)0));
1011 if (path_fd < 0)
1012 return path_fd;
1013
1014 xsprintf(procfs_path, "/proc/self/fd/%i", path_fd)do { if ((__builtin_expect(!!(!(((size_t) snprintf(procfs_path
, __extension__ (__builtin_choose_expr( !__builtin_types_compatible_p
(typeof(procfs_path), typeof(&*(procfs_path))), sizeof(procfs_path
)/sizeof((procfs_path)[0]), ((void)0))), "/proc/self/fd/%i", path_fd
) < (__extension__ (__builtin_choose_expr( !__builtin_types_compatible_p
(typeof(procfs_path), typeof(&*(procfs_path))), sizeof(procfs_path
)/sizeof((procfs_path)[0]), ((void)0))))))),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("xsprintf: " "procfs_path" "[] must be big enough"
), "../src/basic/fs-util.c", 1014, __PRETTY_FUNCTION__); } while
(0);
1015 d = opendir(procfs_path);
1016 if (!d)
1017 return -errno(*__errno_location ());
1018
1019 if (ret_path)
1020 *ret_path = TAKE_PTR(p)({ typeof(p) _ptr_ = (p); (p) = ((void*)0); _ptr_; });
1021
1022 *ret_dir = d;
1023 return 0;
1024}
1025
1026int chase_symlinks_and_stat(
1027 const char *path,
1028 const char *root,
1029 unsigned chase_flags,
1030 char **ret_path,
1031 struct stat *ret_stat) {
1032
1033 _cleanup_close___attribute__((cleanup(closep))) int path_fd = -1;
1034 _cleanup_free___attribute__((cleanup(freep))) char *p = NULL((void*)0);
1035
1036 assert(path)do { if ((__builtin_expect(!!(!(path)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("path"), "../src/basic/fs-util.c", 1036,
__PRETTY_FUNCTION__); } while (0);
1037 assert(ret_stat)do { if ((__builtin_expect(!!(!(ret_stat)),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("ret_stat"), "../src/basic/fs-util.c", 1037
, __PRETTY_FUNCTION__); } while (0);
1038
1039 if (chase_flags & CHASE_NONEXISTENT)
1040 return -EINVAL22;
1041
1042 if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) {
1043 /* Shortcut this call if none of the special features of this call are requested */
1044 if (stat(path, ret_stat) < 0)
1045 return -errno(*__errno_location ());
1046
1047 return 1;
1048 }
1049
1050 path_fd = chase_symlinks(path, root, chase_flags|CHASE_OPEN, ret_path ? &p : NULL((void*)0));
1051 if (path_fd < 0)
1052 return path_fd;
1053
1054 if (fstat(path_fd, ret_stat) < 0)
1055 return -errno(*__errno_location ());
1056
1057 if (ret_path)
1058 *ret_path = TAKE_PTR(p)({ typeof(p) _ptr_ = (p); (p) = ((void*)0); _ptr_; });
1059
1060 if (chase_flags & CHASE_OPEN)
1061 return TAKE_FD(path_fd)({ int _fd_ = (path_fd); (path_fd) = -1; _fd_; });
1062
1063 return 1;
1064}
1065
1066int access_fd(int fd, int mode) {
1067 char p[STRLEN("/proc/self/fd/")(sizeof("""/proc/self/fd/""") - 1) + DECIMAL_STR_MAX(fd)(2+(sizeof(fd) <= 1 ? 3 : sizeof(fd) <= 2 ? 5 : sizeof(
fd) <= 4 ? 10 : sizeof(fd) <= 8 ? 20 : sizeof(int[-2*(sizeof
(fd) > 8)]))) + 1];
1068 int r;
1069
1070 /* Like access() but operates on an already open fd */
1071
1072 xsprintf(p, "/proc/self/fd/%i", fd)do { if ((__builtin_expect(!!(!(((size_t) snprintf(p, __extension__
(__builtin_choose_expr( !__builtin_types_compatible_p(typeof
(p), typeof(&*(p))), sizeof(p)/sizeof((p)[0]), ((void)0))
), "/proc/self/fd/%i", fd) < (__extension__ (__builtin_choose_expr
( !__builtin_types_compatible_p(typeof(p), typeof(&*(p)))
, sizeof(p)/sizeof((p)[0]), ((void)0))))))),0))) log_assert_failed_realm
(LOG_REALM_SYSTEMD, ("xsprintf: " "p" "[] must be big enough"
), "../src/basic/fs-util.c", 1072, __PRETTY_FUNCTION__); } while
(0);
1073 r = access(p, mode);
1074 if (r < 0)
1075 return -errno(*__errno_location ());
1076
1077 return r;
1078}
1079
1080void unlink_tempfilep(char (*p)[]) {
1081 /* If the file is created with mkstemp(), it will (almost always)
1082 * change the suffix. Treat this as a sign that the file was
1083 * successfully created. We ignore both the rare case where the
1084 * original suffix is used and unlink failures. */
1085 if (!endswith(*p, ".XXXXXX"))
1086 (void) unlink_noerrno(*p);
1087}
1088
1089int unlinkat_deallocate(int fd, const char *name, int flags) {
1090 _cleanup_close___attribute__((cleanup(closep))) int truncate_fd = -1;
1091 struct stat st;
1092 off_t l, bs;
1093
1094 /* Operates like unlinkat() but also deallocates the file contents if it is a regular file and there's no other
1095 * link to it. This is useful to ensure that other processes that might have the file open for reading won't be
1096 * able to keep the data pinned on disk forever. This call is particular useful whenever we execute clean-up
1097 * jobs ("vacuuming"), where we want to make sure the data is really gone and the disk space released and
1098 * returned to the free pool.
1099 *
1100 * Deallocation is preferably done by FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE (👊) if supported, which means
1101 * the file won't change size. That's a good thing since we shouldn't needlessly trigger SIGBUS in other
1102 * programs that have mmap()ed the file. (The assumption here is that changing file contents to all zeroes
1103 * underneath those programs is the better choice than simply triggering SIGBUS in them which truncation does.)
1104 * However if hole punching is not implemented in the kernel or file system we'll fall back to normal file
1105 * truncation (đŸ”Ē), as our goal of deallocating the data space trumps our goal of being nice to readers (💐).
1106 *
1107 * Note that we attempt deallocation, but failure to succeed with that is not considered fatal, as long as the
1108 * primary job – to delete the file – is accomplished. */
1109
1110 if ((flags & AT_REMOVEDIR0x200) == 0) {
1111 truncate_fd = openat(fd, name, O_WRONLY01|O_CLOEXEC02000000|O_NOCTTY0400|O_NOFOLLOW0400000|O_NONBLOCK04000);
1112 if (truncate_fd < 0) {
1113
1114 /* If this failed because the file doesn't exist propagate the error right-away. Also,
1115 * AT_REMOVEDIR wasn't set, and we tried to open the file for writing, which means EISDIR is
1116 * returned when this is a directory but we are not supposed to delete those, hence propagate
1117 * the error right-away too. */
1118 if (IN_SET(errno, ENOENT, EISDIR)({ _Bool _found = 0; static __attribute__ ((unused)) char _static_assert__macros_need_to_be_extended
[20 - sizeof((int[]){2, 21})/sizeof(int)]; switch((*__errno_location
())) { case 2: case 21: _found = 1; break; default: break; }
_found; }))
1119 return -errno(*__errno_location ());
1120
1121 if (errno(*__errno_location ()) != ELOOP40) /* don't complain if this is a symlink */
1122 log_debug_errno(errno, "Failed to open file '%s' for deallocation, ignoring: %m", name)({ int _level = ((7)), _e = (((*__errno_location ()))), _realm
= (LOG_REALM_SYSTEMD); (log_get_max_level_realm(_realm) >=
((_level) & 0x07)) ? log_internal_realm(((_realm) <<
10 | (_level)), _e, "../src/basic/fs-util.c", 1122, __func__
, "Failed to open file '%s' for deallocation, ignoring: %m", name
) : -abs(_e); });
1123 }
1124 }
1125
1126 if (unlinkat(fd, name, flags) < 0)
1127 return -errno(*__errno_location ());
1128
1129 if (truncate_fd < 0) /* Don't have a file handle, can't do more ☚ī¸ */
1130 return 0;
1131
1132 if (fstat(truncate_fd, &st) < 0) {
1133 log_debug_errno(errno, "Failed to stat file '%s' for deallocation, ignoring.", name)({ int _level = ((7)), _e = (((*__errno_location ()))), _realm
= (LOG_REALM_SYSTEMD); (log_get_max_level_realm(_realm) >=
((_level) & 0x07)) ? log_internal_realm(((_realm) <<
10 | (_level)), _e, "../src/basic/fs-util.c", 1133, __func__
, "Failed to stat file '%s' for deallocation, ignoring.", name
) : -abs(_e); });
1134 return 0;
1135 }
1136
1137 if (!S_ISREG(st.st_mode)((((st.st_mode)) & 0170000) == (0100000)) || st.st_blocks == 0 || st.st_nlink > 0)
1138 return 0;
1139
1140 /* If this is a regular file, it actually took up space on disk and there are no other links it's time to
1141 * punch-hole/truncate this to release the disk space. */
1142
1143 bs = MAX(st.st_blksize, 512)__extension__ ({ const typeof((st.st_blksize)) __unique_prefix_A33
= ((st.st_blksize)); const typeof((512)) __unique_prefix_B34
= ((512)); __unique_prefix_A33 > __unique_prefix_B34 ? __unique_prefix_A33
: __unique_prefix_B34; });
1144 l = DIV_ROUND_UP(st.st_size, bs)({ const typeof((st.st_size)) __unique_prefix_X35 = ((st.st_size
)); const typeof((bs)) __unique_prefix_Y36 = ((bs)); (__unique_prefix_X35
/ __unique_prefix_Y36 + !!(__unique_prefix_X35 % __unique_prefix_Y36
)); }) * bs; /* Round up to next block size */
1145
1146 if (fallocate(truncate_fd, FALLOC_FL_PUNCH_HOLE0x02|FALLOC_FL_KEEP_SIZE0x01, 0, l) >= 0)
1147 return 0; /* Successfully punched a hole! 😊 */
1148
1149 /* Fall back to truncation */
1150 if (ftruncate(truncate_fd, 0) < 0) {
1151 log_debug_errno(errno, "Failed to truncate file to 0, ignoring: %m")({ int _level = ((7)), _e = (((*__errno_location ()))), _realm
= (LOG_REALM_SYSTEMD); (log_get_max_level_realm(_realm) >=
((_level) & 0x07)) ? log_internal_realm(((_realm) <<
10 | (_level)), _e, "../src/basic/fs-util.c", 1151, __func__
, "Failed to truncate file to 0, ignoring: %m") : -abs(_e); }
);
1152 return 0;
1153 }
1154
1155 return 0;
1156}
1157
1158int fsync_directory_of_file(int fd) {
1159 _cleanup_free___attribute__((cleanup(freep))) char *path = NULL((void*)0), *dn = NULL((void*)0);
1160 _cleanup_close___attribute__((cleanup(closep))) int dfd = -1;
1161 int r;
1162
1163 r = fd_verify_regular(fd);
1164 if (r < 0)
1165 return r;
1166
1167 r = fd_get_path(fd, &path);
1168 if (r < 0) {
1169 log_debug_errno(r, "Failed to query /proc/self/fd/%d%s: %m",({ int _level = ((7)), _e = ((r)), _realm = (LOG_REALM_SYSTEMD
); (log_get_max_level_realm(_realm) >= ((_level) & 0x07
)) ? log_internal_realm(((_realm) << 10 | (_level)), _e
, "../src/basic/fs-util.c", 1171, __func__, "Failed to query /proc/self/fd/%d%s: %m"
, fd, r == -95 ? ", ignoring" : "") : -abs(_e); })
1170 fd,({ int _level = ((7)), _e = ((r)), _realm = (LOG_REALM_SYSTEMD
); (log_get_max_level_realm(_realm) >= ((_level) & 0x07
)) ? log_internal_realm(((_realm) << 10 | (_level)), _e
, "../src/basic/fs-util.c", 1171, __func__, "Failed to query /proc/self/fd/%d%s: %m"
, fd, r == -95 ? ", ignoring" : "") : -abs(_e); })
1171 r == -EOPNOTSUPP ? ", ignoring" : "")({ int _level = ((7)), _e = ((r)), _realm = (LOG_REALM_SYSTEMD
); (log_get_max_level_realm(_realm) >= ((_level) & 0x07
)) ? log_internal_realm(((_realm) << 10 | (_level)), _e
, "../src/basic/fs-util.c", 1171, __func__, "Failed to query /proc/self/fd/%d%s: %m"
, fd, r == -95 ? ", ignoring" : "") : -abs(_e); });
1172
1173 if (r == -EOPNOTSUPP95)
1174 /* If /proc is not available, we're most likely running in some
1175 * chroot environment, and syncing the directory is not very
1176 * important in that case. Let's just silently do nothing. */
1177 return 0;
1178
1179 return r;
1180 }
1181
1182 if (!path_is_absolute(path))
1183 return -EINVAL22;
1184
1185 dn = dirname_malloc(path);
1186 if (!dn)
1187 return -ENOMEM12;
1188
1189 dfd = open(dn, O_RDONLY00|O_CLOEXEC02000000|O_DIRECTORY0200000);
1190 if (dfd < 0)
1191 return -errno(*__errno_location ());
1192
1193 if (fsync(dfd) < 0)
1194 return -errno(*__errno_location ());
1195
1196 return 0;
1197}