1 /* SPDX-License-Identifier: LGPL-2.1+ */
9 #include <linux/magic.h>
13 #include "alloc-util.h"
14 #include "dirent-util.h"
20 //#include "missing.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"
29 //#include "time-util.h"
30 #include "user-util.h"
33 /// Additional includes needed by elogind
34 #include "process-util.h"
36 int unlink_noerrno(const char *path) {
47 #if 0 /// UNNEEDED by elogind
48 int rmdir_parents(const char *path, const char *stop) {
57 /* Skip trailing slashes */
58 while (l > 0 && path[l-1] == '/')
64 /* Skip last component */
65 while (l > 0 && path[l-1] != '/')
68 /* Skip trailing slashes */
69 while (l > 0 && path[l-1] == '/')
79 if (path_startswith(stop, t)) {
95 int rename_noreplace(int olddirfd, const char *oldpath, int newdirfd, const char *newpath) {
99 ret = renameat2(olddirfd, oldpath, newdirfd, newpath, RENAME_NOREPLACE);
103 /* renameat2() exists since Linux 3.15, btrfs added support for it later.
104 * If it is not implemented, fallback to another method. */
105 if (!IN_SET(errno, EINVAL, ENOSYS))
108 /* The link()/unlink() fallback does not work on directories. But
109 * renameat() without RENAME_NOREPLACE gives the same semantics on
110 * directories, except when newpath is an *empty* directory. This is
112 ret = fstatat(olddirfd, oldpath, &buf, AT_SYMLINK_NOFOLLOW);
113 if (ret >= 0 && S_ISDIR(buf.st_mode)) {
114 ret = renameat(olddirfd, oldpath, newdirfd, newpath);
115 return ret >= 0 ? 0 : -errno;
118 /* If it is not a directory, use the link()/unlink() fallback. */
119 ret = linkat(olddirfd, oldpath, newdirfd, newpath, 0);
123 ret = unlinkat(olddirfd, oldpath, 0);
125 /* backup errno before the following unlinkat() alters it */
127 (void) unlinkat(newdirfd, newpath, 0);
136 int readlinkat_malloc(int fd, const char *p, char **ret) {
151 n = readlinkat(fd, p, c, l-1);
158 if ((size_t) n < l-1) {
169 int readlink_malloc(const char *p, char **ret) {
170 return readlinkat_malloc(AT_FDCWD, p, ret);
173 #if 0 /// UNNEEDED by elogind
174 int readlink_value(const char *p, char **ret) {
175 _cleanup_free_ char *link = NULL;
179 r = readlink_malloc(p, &link);
183 value = basename(link);
187 value = strdup(value);
197 int readlink_and_make_absolute(const char *p, char **r) {
198 _cleanup_free_ char *target = NULL;
205 j = readlink_malloc(p, &target);
209 k = file_in_same_dir(p, target);
217 #if 0 /// UNNEEDED by elogind
219 int chmod_and_chown(const char *path, mode_t mode, uid_t uid, gid_t gid) {
222 /* Under the assumption that we are running privileged we
223 * first change the access mode and only then hand out
224 * ownership to avoid a window where access is too open. */
226 if (mode != MODE_INVALID)
227 if (chmod(path, mode) < 0)
230 if (uid != UID_INVALID || gid != GID_INVALID)
231 if (chown(path, uid, gid) < 0)
237 int fchmod_umask(int fd, mode_t m) {
242 r = fchmod(fd, m & (~u)) < 0 ? -errno : 0;
248 int fchmod_opath(int fd, mode_t m) {
249 char procfs_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)];
251 /* This function operates also on fd that might have been opened with
252 * O_PATH. Indeed fchmodat() doesn't have the AT_EMPTY_PATH flag like
253 * fchownat() does. */
255 xsprintf(procfs_path, "/proc/self/fd/%i", fd);
257 if (chmod(procfs_path, m) < 0)
263 int fd_warn_permissions(const char *path, int fd) {
266 if (fstat(fd, &st) < 0)
269 if (st.st_mode & 0111)
270 log_warning("Configuration file %s is marked executable. Please remove executable permission bits. Proceeding anyway.", path);
272 if (st.st_mode & 0002)
273 log_warning("Configuration file %s is marked world-writable. Please remove world writability permission bits. Proceeding anyway.", path);
275 if (getpid_cached() == 1 && (st.st_mode & 0044) != 0044)
276 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);
281 int touch_file(const char *path, bool parents, usec_t stamp, uid_t uid, gid_t gid, mode_t mode) {
282 char fdpath[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)];
283 _cleanup_close_ int fd = -1;
288 /* Note that touch_file() does not follow symlinks: if invoked on an existing symlink, then it is the symlink
289 * itself which is updated, not its target
291 * Returns the first error we encounter, but tries to apply as much as possible. */
294 (void) mkdir_parents(path, 0755);
296 /* Initially, we try to open the node with O_PATH, so that we get a reference to the node. This is useful in
297 * case the path refers to an existing device or socket node, as we can open it successfully in all cases, and
298 * won't trigger any driver magic or so. */
299 fd = open(path, O_PATH|O_CLOEXEC|O_NOFOLLOW);
304 /* if the node doesn't exist yet, we create it, but with O_EXCL, so that we only create a regular file
305 * here, and nothing else */
306 fd = open(path, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, IN_SET(mode, 0, MODE_INVALID) ? 0644 : mode);
311 /* Let's make a path from the fd, and operate on that. With this logic, we can adjust the access mode,
312 * ownership and time of the file node in all cases, even if the fd refers to an O_PATH object â which is
313 * something fchown(), fchmod(), futimensat() don't allow. */
314 xsprintf(fdpath, "/proc/self/fd/%i", fd);
316 if (mode != MODE_INVALID)
317 if (chmod(fdpath, mode) < 0)
320 if (uid_is_valid(uid) || gid_is_valid(gid))
321 if (chown(fdpath, uid, gid) < 0 && ret >= 0)
324 if (stamp != USEC_INFINITY) {
325 struct timespec ts[2];
327 timespec_store(&ts[0], stamp);
329 r = utimensat(AT_FDCWD, fdpath, ts, 0);
331 r = utimensat(AT_FDCWD, fdpath, NULL, 0);
332 if (r < 0 && ret >= 0)
338 int touch(const char *path) {
339 return touch_file(path, false, USEC_INFINITY, UID_INVALID, GID_INVALID, MODE_INVALID);
342 #if 0 /// UNNEEDED by elogind
343 int symlink_idempotent(const char *from, const char *to) {
349 if (symlink(from, to) < 0) {
350 _cleanup_free_ char *p = NULL;
355 r = readlink_malloc(to, &p);
356 if (r == -EINVAL) /* Not a symlink? In that case return the original error we encountered: -EEXIST */
358 if (r < 0) /* Any other error? In that case propagate it as is */
361 if (!streq(p, from)) /* Not the symlink we want it to be? In that case, propagate the original -EEXIST */
368 int symlink_atomic(const char *from, const char *to) {
369 _cleanup_free_ char *t = NULL;
375 r = tempfn_random(to, NULL, &t);
379 if (symlink(from, t) < 0)
382 if (rename(t, to) < 0) {
390 int mknod_atomic(const char *path, mode_t mode, dev_t dev) {
391 _cleanup_free_ char *t = NULL;
396 r = tempfn_random(path, NULL, &t);
400 if (mknod(t, mode, dev) < 0)
403 if (rename(t, path) < 0) {
411 int mkfifo_atomic(const char *path, mode_t mode) {
412 _cleanup_free_ char *t = NULL;
417 r = tempfn_random(path, NULL, &t);
421 if (mkfifo(t, mode) < 0)
424 if (rename(t, path) < 0) {
433 int get_files_in_directory(const char *path, char ***list) {
434 _cleanup_closedir_ DIR *d = NULL;
436 size_t bufsize = 0, n = 0;
437 _cleanup_strv_free_ char **l = NULL;
441 /* Returns all files in a directory in *list, and the number
442 * of files as return value. If list is NULL returns only the
449 FOREACH_DIRENT_ALL(de, d, return -errno) {
450 dirent_ensure_type(d, de);
452 if (!dirent_is_file(de))
456 /* one extra slot is needed for the terminating NULL */
457 if (!GREEDY_REALLOC(l, bufsize, n + 2))
460 l[n] = strdup(de->d_name);
475 static int getenv_tmp_dir(const char **ret_path) {
481 /* We use the same order of environment variables python uses in tempfile.gettempdir():
482 * https://docs.python.org/3/library/tempfile.html#tempfile.gettempdir */
483 FOREACH_STRING(n, "TMPDIR", "TEMP", "TMP") {
486 e = secure_getenv(n);
489 if (!path_is_absolute(e)) {
493 if (!path_is_normalized(e)) {
510 /* Remember first error, to make this more debuggable */
522 static int tmp_dir_internal(const char *def, const char **ret) {
529 r = getenv_tmp_dir(&e);
535 k = is_dir(def, true);
539 return r < 0 ? r : k;
545 #if 0 /// UNNEEDED by elogind
546 int var_tmp_dir(const char **ret) {
548 /* Returns the location for "larger" temporary files, that is backed by physical storage if available, and thus
549 * even might survive a boot: /var/tmp. If $TMPDIR (or related environment variables) are set, its value is
550 * returned preferably however. Note that both this function and tmp_dir() below are affected by $TMPDIR,
551 * making it a variable that overrides all temporary file storage locations. */
553 return tmp_dir_internal("/var/tmp", ret);
557 int tmp_dir(const char **ret) {
559 /* Similar to var_tmp_dir() above, but returns the location for "smaller" temporary files, which is usually
560 * backed by an in-memory file system: /tmp. */
562 return tmp_dir_internal("/tmp", ret);
565 int unlink_or_warn(const char *filename) {
566 if (unlink(filename) < 0 && errno != ENOENT)
567 /* If the file doesn't exist and the fs simply was read-only (in which
568 * case unlink() returns EROFS even if the file doesn't exist), don't
570 if (errno != EROFS || access(filename, F_OK) >= 0)
571 return log_error_errno(errno, "Failed to remove \"%s\": %m", filename);
576 #if 0 /// UNNEEDED by elogind
577 int inotify_add_watch_fd(int fd, int what, uint32_t mask) {
578 char path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1];
581 /* This is like inotify_add_watch(), except that the file to watch is not referenced by a path, but by an fd */
582 xsprintf(path, "/proc/self/fd/%i", what);
584 r = inotify_add_watch(fd, path, mask);
592 static bool safe_transition(const struct stat *a, const struct stat *b) {
593 /* Returns true if the transition from a to b is safe, i.e. that we never transition from unprivileged to
594 * privileged files or directories. Why bother? So that unprivileged code can't symlink to privileged files
595 * making us believe we read something safe even though it isn't safe in the specific context we open it in. */
597 if (a->st_uid == 0) /* Transitioning from privileged to unprivileged is always fine */
600 return a->st_uid == b->st_uid; /* Otherwise we need to stay within the same UID */
603 int chase_symlinks(const char *path, const char *original_root, unsigned flags, char **ret) {
604 _cleanup_free_ char *buffer = NULL, *done = NULL, *root = NULL;
605 _cleanup_close_ int fd = -1;
606 unsigned max_follow = CHASE_SYMLINKS_MAX; /* how many symlinks to follow before giving up and returning ELOOP */
607 struct stat previous_stat;
614 /* Either the file may be missing, or we return an fd to the final object, but both make no sense */
615 if (FLAGS_SET(flags, CHASE_NONEXISTENT | CHASE_OPEN))
618 if (FLAGS_SET(flags, CHASE_STEP | CHASE_OPEN))
624 /* This is a lot like canonicalize_file_name(), but takes an additional "root" parameter, that allows following
625 * symlinks relative to a root directory, instead of the root of the host.
627 * Note that "root" primarily matters if we encounter an absolute symlink. It is also used when following
628 * relative symlinks to ensure they cannot be used to "escape" the root directory. The path parameter passed is
629 * assumed to be already prefixed by it, except if the CHASE_PREFIX_ROOT flag is set, in which case it is first
630 * prefixed accordingly.
632 * Algorithmically this operates on two path buffers: "done" are the components of the path we already
633 * processed and resolved symlinks, "." and ".." of. "todo" are the components of the path we still need to
634 * process. On each iteration, we move one component from "todo" to "done", processing it's special meaning
635 * each time. The "todo" path always starts with at least one slash, the "done" path always ends in no
636 * slash. We always keep an O_PATH fd to the component we are currently processing, thus keeping lookup races
639 * Suggested usage: whenever you want to canonicalize a path, use this function. Pass the absolute path you got
640 * as-is: fully qualified and relative to your host's root. Optionally, specify the root parameter to tell this
641 * function what to do when encountering a symlink with an absolute path as directory: prefix it by the
644 * There are three ways to invoke this function:
646 * 1. Without CHASE_STEP or CHASE_OPEN: in this case the path is resolved and the normalized path is returned
647 * in `ret`. The return value is < 0 on error. If CHASE_NONEXISTENT is also set 0 is returned if the file
648 * doesn't exist, > 0 otherwise. If CHASE_NONEXISTENT is not set >= 0 is returned if the destination was
649 * found, -ENOENT if it doesn't.
651 * 2. With CHASE_OPEN: in this case the destination is opened after chasing it as O_PATH and this file
652 * descriptor is returned as return value. This is useful to open files relative to some root
653 * directory. Note that the returned O_PATH file descriptors must be converted into a regular one (using
654 * fd_reopen() or such) before it can be used for reading/writing. CHASE_OPEN may not be combined with
657 * 3. With CHASE_STEP: in this case only a single step of the normalization is executed, i.e. only the first
658 * symlink or ".." component of the path is resolved, and the resulting path is returned. This is useful if
659 * a caller wants to trace the a path through the file system verbosely. Returns < 0 on error, > 0 if the
660 * path is fully normalized, and == 0 for each normalization step. This may be combined with
661 * CHASE_NONEXISTENT, in which case 1 is returned when a component is not found.
665 /* A root directory of "/" or "" is identical to none */
666 if (empty_or_root(original_root))
667 original_root = NULL;
669 if (!original_root && !ret && (flags & (CHASE_NONEXISTENT|CHASE_NO_AUTOFS|CHASE_SAFE|CHASE_OPEN|CHASE_STEP)) == CHASE_OPEN) {
670 /* Shortcut the CHASE_OPEN case if the caller isn't interested in the actual path and has no root set
671 * and doesn't care about any of the other special features we provide either. */
672 r = open(path, O_PATH|O_CLOEXEC);
680 r = path_make_absolute_cwd(original_root, &root);
684 if (flags & CHASE_PREFIX_ROOT) {
686 /* We don't support relative paths in combination with a root directory */
687 if (!path_is_absolute(path))
690 path = prefix_roota(root, path);
694 r = path_make_absolute_cwd(path, &buffer);
698 fd = open("/", O_CLOEXEC|O_NOFOLLOW|O_PATH);
702 if (flags & CHASE_SAFE) {
703 if (fstat(fd, &previous_stat) < 0)
709 _cleanup_free_ char *first = NULL;
710 _cleanup_close_ int child = -1;
714 /* Determine length of first component in the path */
715 n = strspn(todo, "/"); /* The slashes */
716 m = n + strcspn(todo + n, "/"); /* The entire length of the component */
718 /* Extract the first component. */
719 first = strndup(todo, m);
725 /* Empty? Then we reached the end. */
729 /* Just a single slash? Then we reached the end. */
730 if (path_equal(first, "/")) {
731 /* Preserve the trailing slash */
733 if (flags & CHASE_TRAIL_SLASH)
734 if (!strextend(&done, "/", NULL))
740 /* Just a dot? Then let's eat this up. */
741 if (path_equal(first, "/."))
744 /* Two dots? Then chop off the last bit of what we already found out. */
745 if (path_equal(first, "/..")) {
746 _cleanup_free_ char *parent = NULL;
747 _cleanup_close_ int fd_parent = -1;
749 /* If we already are at the top, then going up will not change anything. This is in-line with
750 * how the kernel handles this. */
751 if (empty_or_root(done))
754 parent = dirname_malloc(done);
758 /* Don't allow this to leave the root dir. */
760 path_startswith(done, root) &&
761 !path_startswith(parent, root))
764 free_and_replace(done, parent);
766 if (flags & CHASE_STEP)
769 fd_parent = openat(fd, "..", O_CLOEXEC|O_NOFOLLOW|O_PATH);
773 if (flags & CHASE_SAFE) {
774 if (fstat(fd_parent, &st) < 0)
777 if (!safe_transition(&previous_stat, &st))
784 fd = TAKE_FD(fd_parent);
789 /* Otherwise let's see what this is. */
790 child = openat(fd, first + n, O_CLOEXEC|O_NOFOLLOW|O_PATH);
793 if (errno == ENOENT &&
794 (flags & CHASE_NONEXISTENT) &&
795 (isempty(todo) || path_is_normalized(todo))) {
797 /* If CHASE_NONEXISTENT is set, and the path does not exist, then that's OK, return
798 * what we got so far. But don't allow this if the remaining path contains "../ or "./"
799 * or something else weird. */
801 /* If done is "/", as first also contains slash at the head, then remove this redundant slash. */
802 if (streq_ptr(done, "/"))
805 if (!strextend(&done, first, todo, NULL))
815 if (fstat(child, &st) < 0)
817 if ((flags & CHASE_SAFE) &&
818 !safe_transition(&previous_stat, &st))
823 if ((flags & CHASE_NO_AUTOFS) &&
824 fd_is_fs_type(child, AUTOFS_SUPER_MAGIC) > 0)
827 if (S_ISLNK(st.st_mode)) {
830 _cleanup_free_ char *destination = NULL;
832 /* This is a symlink, in this case read the destination. But let's make sure we don't follow
833 * symlinks without bounds. */
834 if (--max_follow <= 0)
837 r = readlinkat_malloc(fd, first + n, &destination);
840 if (isempty(destination))
843 if (path_is_absolute(destination)) {
845 /* An absolute destination. Start the loop from the beginning, but use the root
846 * directory as base. */
849 fd = open(root ?: "/", O_CLOEXEC|O_NOFOLLOW|O_PATH);
853 if (flags & CHASE_SAFE) {
854 if (fstat(fd, &st) < 0)
857 if (!safe_transition(&previous_stat, &st))
865 /* Note that we do not revalidate the root, we take it as is. */
874 /* Prefix what's left to do with what we just read, and start the loop again, but
875 * remain in the current directory. */
876 joined = strjoin(destination, todo);
878 joined = strjoin("/", destination, todo);
883 todo = buffer = joined;
885 if (flags & CHASE_STEP)
891 /* If this is not a symlink, then let's just add the name we read to what we already verified. */
893 done = TAKE_PTR(first);
895 /* If done is "/", as first also contains slash at the head, then remove this redundant slash. */
896 if (streq(done, "/"))
899 if (!strextend(&done, first, NULL))
903 /* And iterate again, but go one directory further down. */
909 /* Special case, turn the empty string into "/", to indicate the root directory. */
916 *ret = TAKE_PTR(done);
918 if (flags & CHASE_OPEN) {
919 /* Return the O_PATH fd we currently are looking to the caller. It can translate it to a proper fd by
920 * opening /proc/self/fd/xyz. */
926 if (flags & CHASE_STEP)
935 c = strjoin(strempty(done), todo);
945 int chase_symlinks_and_open(
948 unsigned chase_flags,
952 _cleanup_close_ int path_fd = -1;
953 _cleanup_free_ char *p = NULL;
956 if (chase_flags & CHASE_NONEXISTENT)
959 if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) {
960 /* Shortcut this call if none of the special features of this call are requested */
961 r = open(path, open_flags);
968 path_fd = chase_symlinks(path, root, chase_flags|CHASE_OPEN, ret_path ? &p : NULL);
972 r = fd_reopen(path_fd, open_flags);
977 *ret_path = TAKE_PTR(p);
982 int chase_symlinks_and_opendir(
985 unsigned chase_flags,
989 char procfs_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)];
990 _cleanup_close_ int path_fd = -1;
991 _cleanup_free_ char *p = NULL;
996 if (chase_flags & CHASE_NONEXISTENT)
999 if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) {
1000 /* Shortcut this call if none of the special features of this call are requested */
1009 path_fd = chase_symlinks(path, root, chase_flags|CHASE_OPEN, ret_path ? &p : NULL);
1013 xsprintf(procfs_path, "/proc/self/fd/%i", path_fd);
1014 d = opendir(procfs_path);
1019 *ret_path = TAKE_PTR(p);
1025 int chase_symlinks_and_stat(
1028 unsigned chase_flags,
1030 struct stat *ret_stat) {
1032 _cleanup_close_ int path_fd = -1;
1033 _cleanup_free_ char *p = NULL;
1038 if (chase_flags & CHASE_NONEXISTENT)
1041 if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) {
1042 /* Shortcut this call if none of the special features of this call are requested */
1043 if (stat(path, ret_stat) < 0)
1049 path_fd = chase_symlinks(path, root, chase_flags|CHASE_OPEN, ret_path ? &p : NULL);
1053 if (fstat(path_fd, ret_stat) < 0)
1057 *ret_path = TAKE_PTR(p);
1059 if (chase_flags & CHASE_OPEN)
1060 return TAKE_FD(path_fd);
1065 int access_fd(int fd, int mode) {
1066 char p[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(fd) + 1];
1069 /* Like access() but operates on an already open fd */
1071 xsprintf(p, "/proc/self/fd/%i", fd);
1072 r = access(p, mode);
1079 void unlink_tempfilep(char (*p)[]) {
1080 /* If the file is created with mkstemp(), it will (almost always)
1081 * change the suffix. Treat this as a sign that the file was
1082 * successfully created. We ignore both the rare case where the
1083 * original suffix is used and unlink failures. */
1084 if (!endswith(*p, ".XXXXXX"))
1085 (void) unlink_noerrno(*p);
1088 int unlinkat_deallocate(int fd, const char *name, int flags) {
1089 _cleanup_close_ int truncate_fd = -1;
1093 /* Operates like unlinkat() but also deallocates the file contents if it is a regular file and there's no other
1094 * link to it. This is useful to ensure that other processes that might have the file open for reading won't be
1095 * able to keep the data pinned on disk forever. This call is particular useful whenever we execute clean-up
1096 * jobs ("vacuuming"), where we want to make sure the data is really gone and the disk space released and
1097 * returned to the free pool.
1099 * Deallocation is preferably done by FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE (đ) if supported, which means
1100 * the file won't change size. That's a good thing since we shouldn't needlessly trigger SIGBUS in other
1101 * programs that have mmap()ed the file. (The assumption here is that changing file contents to all zeroes
1102 * underneath those programs is the better choice than simply triggering SIGBUS in them which truncation does.)
1103 * However if hole punching is not implemented in the kernel or file system we'll fall back to normal file
1104 * truncation (đĒ), as our goal of deallocating the data space trumps our goal of being nice to readers (đ).
1106 * Note that we attempt deallocation, but failure to succeed with that is not considered fatal, as long as the
1107 * primary job â to delete the file â is accomplished. */
1109 if ((flags & AT_REMOVEDIR) == 0) {
1110 truncate_fd = openat(fd, name, O_WRONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW|O_NONBLOCK);
1111 if (truncate_fd < 0) {
1113 /* If this failed because the file doesn't exist propagate the error right-away. Also,
1114 * AT_REMOVEDIR wasn't set, and we tried to open the file for writing, which means EISDIR is
1115 * returned when this is a directory but we are not supposed to delete those, hence propagate
1116 * the error right-away too. */
1117 if (IN_SET(errno, ENOENT, EISDIR))
1120 if (errno != ELOOP) /* don't complain if this is a symlink */
1121 log_debug_errno(errno, "Failed to open file '%s' for deallocation, ignoring: %m", name);
1125 if (unlinkat(fd, name, flags) < 0)
1128 if (truncate_fd < 0) /* Don't have a file handle, can't do more âšī¸ */
1131 if (fstat(truncate_fd, &st) < 0) {
1132 log_debug_errno(errno, "Failed to stat file '%s' for deallocation, ignoring.", name);
1136 if (!S_ISREG(st.st_mode) || st.st_blocks == 0 || st.st_nlink > 0)
1139 /* If this is a regular file, it actually took up space on disk and there are no other links it's time to
1140 * punch-hole/truncate this to release the disk space. */
1142 bs = MAX(st.st_blksize, 512);
1143 l = DIV_ROUND_UP(st.st_size, bs) * bs; /* Round up to next block size */
1145 if (fallocate(truncate_fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE, 0, l) >= 0)
1146 return 0; /* Successfully punched a hole! đ */
1148 /* Fall back to truncation */
1149 if (ftruncate(truncate_fd, 0) < 0) {
1150 log_debug_errno(errno, "Failed to truncate file to 0, ignoring: %m");
1157 int fsync_directory_of_file(int fd) {
1158 _cleanup_free_ char *path = NULL, *dn = NULL;
1159 _cleanup_close_ int dfd = -1;
1162 r = fd_verify_regular(fd);
1166 r = fd_get_path(fd, &path);
1168 log_debug_errno(r, "Failed to query /proc/self/fd/%d%s: %m",
1170 r == -EOPNOTSUPP ? ", ignoring" : "");
1172 if (r == -EOPNOTSUPP)
1173 /* If /proc is not available, we're most likely running in some
1174 * chroot environment, and syncing the directory is not very
1175 * important in that case. Let's just silently do nothing. */
1181 if (!path_is_absolute(path))
1184 dn = dirname_malloc(path);
1188 dfd = open(dn, O_RDONLY|O_CLOEXEC|O_DIRECTORY);