1 /* SPDX-License-Identifier: LGPL-2.1+ */
3 This file is part of systemd.
5 Copyright 2010 Lennart Poettering
14 #include <linux/magic.h>
18 #include "alloc-util.h"
19 #include "dirent-util.h"
25 //#include "missing.h"
27 #include "parse-util.h"
28 #include "path-util.h"
29 //#include "process-util.h"
30 #include "stat-util.h"
31 #include "stdio-util.h"
32 #include "string-util.h"
34 //#include "time-util.h"
35 #include "user-util.h"
38 /// Additional includes needed by elogind
39 #include "process-util.h"
41 int unlink_noerrno(const char *path) {
52 #if 0 /// UNNEEDED by elogind
53 int rmdir_parents(const char *path, const char *stop) {
62 /* Skip trailing slashes */
63 while (l > 0 && path[l-1] == '/')
69 /* Skip last component */
70 while (l > 0 && path[l-1] != '/')
73 /* Skip trailing slashes */
74 while (l > 0 && path[l-1] == '/')
84 if (path_startswith(stop, t)) {
100 int rename_noreplace(int olddirfd, const char *oldpath, int newdirfd, const char *newpath) {
104 ret = renameat2(olddirfd, oldpath, newdirfd, newpath, RENAME_NOREPLACE);
108 /* renameat2() exists since Linux 3.15, btrfs added support for it later.
109 * If it is not implemented, fallback to another method. */
110 if (!IN_SET(errno, EINVAL, ENOSYS))
113 /* The link()/unlink() fallback does not work on directories. But
114 * renameat() without RENAME_NOREPLACE gives the same semantics on
115 * directories, except when newpath is an *empty* directory. This is
117 ret = fstatat(olddirfd, oldpath, &buf, AT_SYMLINK_NOFOLLOW);
118 if (ret >= 0 && S_ISDIR(buf.st_mode)) {
119 ret = renameat(olddirfd, oldpath, newdirfd, newpath);
120 return ret >= 0 ? 0 : -errno;
123 /* If it is not a directory, use the link()/unlink() fallback. */
124 ret = linkat(olddirfd, oldpath, newdirfd, newpath, 0);
128 ret = unlinkat(olddirfd, oldpath, 0);
130 /* backup errno before the following unlinkat() alters it */
132 (void) unlinkat(newdirfd, newpath, 0);
141 int readlinkat_malloc(int fd, const char *p, char **ret) {
156 n = readlinkat(fd, p, c, l-1);
163 if ((size_t) n < l-1) {
174 int readlink_malloc(const char *p, char **ret) {
175 return readlinkat_malloc(AT_FDCWD, p, ret);
178 #if 0 /// UNNEEDED by elogind
179 int readlink_value(const char *p, char **ret) {
180 _cleanup_free_ char *link = NULL;
184 r = readlink_malloc(p, &link);
188 value = basename(link);
192 value = strdup(value);
202 int readlink_and_make_absolute(const char *p, char **r) {
203 _cleanup_free_ char *target = NULL;
210 j = readlink_malloc(p, &target);
214 k = file_in_same_dir(p, target);
222 #if 0 /// UNNEEDED by elogind
224 int chmod_and_chown(const char *path, mode_t mode, uid_t uid, gid_t gid) {
227 /* Under the assumption that we are running privileged we
228 * first change the access mode and only then hand out
229 * ownership to avoid a window where access is too open. */
231 if (mode != MODE_INVALID)
232 if (chmod(path, mode) < 0)
235 if (uid != UID_INVALID || gid != GID_INVALID)
236 if (chown(path, uid, gid) < 0)
242 int fchmod_and_chown(int fd, mode_t mode, uid_t uid, gid_t gid) {
243 /* Under the assumption that we are running privileged we
244 * first change the access mode and only then hand out
245 * ownership to avoid a window where access is too open. */
247 if (mode != MODE_INVALID)
248 if (fchmod(fd, mode) < 0)
251 if (uid != UID_INVALID || gid != GID_INVALID)
252 if (fchown(fd, uid, gid) < 0)
258 int fchmod_umask(int fd, mode_t m) {
263 r = fchmod(fd, m & (~u)) < 0 ? -errno : 0;
269 int fchmod_opath(int fd, mode_t m) {
270 char procfs_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)];
272 /* This function operates also on fd that might have been opened with
273 * O_PATH. Indeed fchmodat() doesn't have the AT_EMPTY_PATH flag like
274 * fchownat() does. */
276 xsprintf(procfs_path, "/proc/self/fd/%i", fd);
278 if (chmod(procfs_path, m) < 0)
284 int fd_warn_permissions(const char *path, int fd) {
287 if (fstat(fd, &st) < 0)
290 if (st.st_mode & 0111)
291 log_warning("Configuration file %s is marked executable. Please remove executable permission bits. Proceeding anyway.", path);
293 if (st.st_mode & 0002)
294 log_warning("Configuration file %s is marked world-writable. Please remove world writability permission bits. Proceeding anyway.", path);
296 if (getpid_cached() == 1 && (st.st_mode & 0044) != 0044)
297 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);
302 int touch_file(const char *path, bool parents, usec_t stamp, uid_t uid, gid_t gid, mode_t mode) {
303 char fdpath[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)];
304 _cleanup_close_ int fd = -1;
309 /* Note that touch_file() does not follow symlinks: if invoked on an existing symlink, then it is the symlink
310 * itself which is updated, not its target
312 * Returns the first error we encounter, but tries to apply as much as possible. */
315 (void) mkdir_parents(path, 0755);
317 /* Initially, we try to open the node with O_PATH, so that we get a reference to the node. This is useful in
318 * case the path refers to an existing device or socket node, as we can open it successfully in all cases, and
319 * won't trigger any driver magic or so. */
320 fd = open(path, O_PATH|O_CLOEXEC|O_NOFOLLOW);
325 /* if the node doesn't exist yet, we create it, but with O_EXCL, so that we only create a regular file
326 * here, and nothing else */
327 fd = open(path, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, IN_SET(mode, 0, MODE_INVALID) ? 0644 : mode);
332 /* Let's make a path from the fd, and operate on that. With this logic, we can adjust the access mode,
333 * ownership and time of the file node in all cases, even if the fd refers to an O_PATH object â which is
334 * something fchown(), fchmod(), futimensat() don't allow. */
335 xsprintf(fdpath, "/proc/self/fd/%i", fd);
337 if (mode != MODE_INVALID)
338 if (chmod(fdpath, mode) < 0)
341 if (uid_is_valid(uid) || gid_is_valid(gid))
342 if (chown(fdpath, uid, gid) < 0 && ret >= 0)
345 if (stamp != USEC_INFINITY) {
346 struct timespec ts[2];
348 timespec_store(&ts[0], stamp);
350 r = utimensat(AT_FDCWD, fdpath, ts, 0);
352 r = utimensat(AT_FDCWD, fdpath, NULL, 0);
353 if (r < 0 && ret >= 0)
359 int touch(const char *path) {
360 return touch_file(path, false, USEC_INFINITY, UID_INVALID, GID_INVALID, MODE_INVALID);
363 #if 0 /// UNNEEDED by elogind
364 int symlink_idempotent(const char *from, const char *to) {
370 if (symlink(from, to) < 0) {
371 _cleanup_free_ char *p = NULL;
376 r = readlink_malloc(to, &p);
377 if (r == -EINVAL) /* Not a symlink? In that case return the original error we encountered: -EEXIST */
379 if (r < 0) /* Any other error? In that case propagate it as is */
382 if (!streq(p, from)) /* Not the symlink we want it to be? In that case, propagate the original -EEXIST */
389 int symlink_atomic(const char *from, const char *to) {
390 _cleanup_free_ char *t = NULL;
396 r = tempfn_random(to, NULL, &t);
400 if (symlink(from, t) < 0)
403 if (rename(t, to) < 0) {
411 int mknod_atomic(const char *path, mode_t mode, dev_t dev) {
412 _cleanup_free_ char *t = NULL;
417 r = tempfn_random(path, NULL, &t);
421 if (mknod(t, mode, dev) < 0)
424 if (rename(t, path) < 0) {
432 int mkfifo_atomic(const char *path, mode_t mode) {
433 _cleanup_free_ char *t = NULL;
438 r = tempfn_random(path, NULL, &t);
442 if (mkfifo(t, mode) < 0)
445 if (rename(t, path) < 0) {
454 int get_files_in_directory(const char *path, char ***list) {
455 _cleanup_closedir_ DIR *d = NULL;
457 size_t bufsize = 0, n = 0;
458 _cleanup_strv_free_ char **l = NULL;
462 /* Returns all files in a directory in *list, and the number
463 * of files as return value. If list is NULL returns only the
470 FOREACH_DIRENT_ALL(de, d, return -errno) {
471 dirent_ensure_type(d, de);
473 if (!dirent_is_file(de))
477 /* one extra slot is needed for the terminating NULL */
478 if (!GREEDY_REALLOC(l, bufsize, n + 2))
481 l[n] = strdup(de->d_name);
496 static int getenv_tmp_dir(const char **ret_path) {
502 /* We use the same order of environment variables python uses in tempfile.gettempdir():
503 * https://docs.python.org/3/library/tempfile.html#tempfile.gettempdir */
504 FOREACH_STRING(n, "TMPDIR", "TEMP", "TMP") {
507 e = secure_getenv(n);
510 if (!path_is_absolute(e)) {
514 if (!path_is_normalized(e)) {
531 /* Remember first error, to make this more debuggable */
543 static int tmp_dir_internal(const char *def, const char **ret) {
550 r = getenv_tmp_dir(&e);
556 k = is_dir(def, true);
560 return r < 0 ? r : k;
566 #if 0 /// UNNEEDED by elogind
567 int var_tmp_dir(const char **ret) {
569 /* Returns the location for "larger" temporary files, that is backed by physical storage if available, and thus
570 * even might survive a boot: /var/tmp. If $TMPDIR (or related environment variables) are set, its value is
571 * returned preferably however. Note that both this function and tmp_dir() below are affected by $TMPDIR,
572 * making it a variable that overrides all temporary file storage locations. */
574 return tmp_dir_internal("/var/tmp", ret);
578 int tmp_dir(const char **ret) {
580 /* Similar to var_tmp_dir() above, but returns the location for "smaller" temporary files, which is usually
581 * backed by an in-memory file system: /tmp. */
583 return tmp_dir_internal("/tmp", ret);
586 int unlink_or_warn(const char *filename) {
587 if (unlink(filename) < 0 && errno != ENOENT)
588 /* If the file doesn't exist and the fs simply was read-only (in which
589 * case unlink() returns EROFS even if the file doesn't exist), don't
591 if (errno != EROFS || access(filename, F_OK) >= 0)
592 return log_error_errno(errno, "Failed to remove \"%s\": %m", filename);
597 #if 0 /// UNNEEDED by elogind
598 int inotify_add_watch_fd(int fd, int what, uint32_t mask) {
599 char path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1];
602 /* This is like inotify_add_watch(), except that the file to watch is not referenced by a path, but by an fd */
603 xsprintf(path, "/proc/self/fd/%i", what);
605 r = inotify_add_watch(fd, path, mask);
613 static bool safe_transition(const struct stat *a, const struct stat *b) {
614 /* Returns true if the transition from a to b is safe, i.e. that we never transition from unprivileged to
615 * privileged files or directories. Why bother? So that unprivileged code can't symlink to privileged files
616 * making us believe we read something safe even though it isn't safe in the specific context we open it in. */
618 if (a->st_uid == 0) /* Transitioning from privileged to unprivileged is always fine */
621 return a->st_uid == b->st_uid; /* Otherwise we need to stay within the same UID */
624 int chase_symlinks(const char *path, const char *original_root, unsigned flags, char **ret) {
625 _cleanup_free_ char *buffer = NULL, *done = NULL, *root = NULL;
626 _cleanup_close_ int fd = -1;
627 unsigned max_follow = CHASE_SYMLINKS_MAX; /* how many symlinks to follow before giving up and returning ELOOP */
628 struct stat previous_stat;
635 /* Either the file may be missing, or we return an fd to the final object, but both make no sense */
636 if (FLAGS_SET(flags, CHASE_NONEXISTENT | CHASE_OPEN))
639 if (FLAGS_SET(flags, CHASE_STEP | CHASE_OPEN))
645 /* This is a lot like canonicalize_file_name(), but takes an additional "root" parameter, that allows following
646 * symlinks relative to a root directory, instead of the root of the host.
648 * Note that "root" primarily matters if we encounter an absolute symlink. It is also used when following
649 * relative symlinks to ensure they cannot be used to "escape" the root directory. The path parameter passed is
650 * assumed to be already prefixed by it, except if the CHASE_PREFIX_ROOT flag is set, in which case it is first
651 * prefixed accordingly.
653 * Algorithmically this operates on two path buffers: "done" are the components of the path we already
654 * processed and resolved symlinks, "." and ".." of. "todo" are the components of the path we still need to
655 * process. On each iteration, we move one component from "todo" to "done", processing it's special meaning
656 * each time. The "todo" path always starts with at least one slash, the "done" path always ends in no
657 * slash. We always keep an O_PATH fd to the component we are currently processing, thus keeping lookup races
660 * Suggested usage: whenever you want to canonicalize a path, use this function. Pass the absolute path you got
661 * as-is: fully qualified and relative to your host's root. Optionally, specify the root parameter to tell this
662 * function what to do when encountering a symlink with an absolute path as directory: prefix it by the
665 * There are three ways to invoke this function:
667 * 1. Without CHASE_STEP or CHASE_OPEN: in this case the path is resolved and the normalized path is returned
668 * in `ret`. The return value is < 0 on error. If CHASE_NONEXISTENT is also set 0 is returned if the file
669 * doesn't exist, > 0 otherwise. If CHASE_NONEXISTENT is not set >= 0 is returned if the destination was
670 * found, -ENOENT if it doesn't.
672 * 2. With CHASE_OPEN: in this case the destination is opened after chasing it as O_PATH and this file
673 * descriptor is returned as return value. This is useful to open files relative to some root
674 * directory. Note that the returned O_PATH file descriptors must be converted into a regular one (using
675 * fd_reopen() or such) before it can be used for reading/writing. CHASE_OPEN may not be combined with
678 * 3. With CHASE_STEP: in this case only a single step of the normalization is executed, i.e. only the first
679 * symlink or ".." component of the path is resolved, and the resulting path is returned. This is useful if
680 * a caller wants to trace the a path through the file system verbosely. Returns < 0 on error, > 0 if the
681 * path is fully normalized, and == 0 for each normalization step. This may be combined with
682 * CHASE_NONEXISTENT, in which case 1 is returned when a component is not found.
686 /* A root directory of "/" or "" is identical to none */
687 if (empty_or_root(original_root))
688 original_root = NULL;
690 if (!original_root && !ret && (flags & (CHASE_NONEXISTENT|CHASE_NO_AUTOFS|CHASE_SAFE|CHASE_OPEN|CHASE_STEP)) == CHASE_OPEN) {
691 /* Shortcut the CHASE_OPEN case if the caller isn't interested in the actual path and has no root set
692 * and doesn't care about any of the other special features we provide either. */
693 r = open(path, O_PATH|O_CLOEXEC);
701 r = path_make_absolute_cwd(original_root, &root);
705 if (flags & CHASE_PREFIX_ROOT) {
707 /* We don't support relative paths in combination with a root directory */
708 if (!path_is_absolute(path))
711 path = prefix_roota(root, path);
715 r = path_make_absolute_cwd(path, &buffer);
719 fd = open("/", O_CLOEXEC|O_NOFOLLOW|O_PATH);
723 if (flags & CHASE_SAFE) {
724 if (fstat(fd, &previous_stat) < 0)
730 _cleanup_free_ char *first = NULL;
731 _cleanup_close_ int child = -1;
735 /* Determine length of first component in the path */
736 n = strspn(todo, "/"); /* The slashes */
737 m = n + strcspn(todo + n, "/"); /* The entire length of the component */
739 /* Extract the first component. */
740 first = strndup(todo, m);
746 /* Empty? Then we reached the end. */
750 /* Just a single slash? Then we reached the end. */
751 if (path_equal(first, "/")) {
752 /* Preserve the trailing slash */
754 if (flags & CHASE_TRAIL_SLASH)
755 if (!strextend(&done, "/", NULL))
761 /* Just a dot? Then let's eat this up. */
762 if (path_equal(first, "/."))
765 /* Two dots? Then chop off the last bit of what we already found out. */
766 if (path_equal(first, "/..")) {
767 _cleanup_free_ char *parent = NULL;
768 _cleanup_close_ int fd_parent = -1;
770 /* If we already are at the top, then going up will not change anything. This is in-line with
771 * how the kernel handles this. */
772 if (empty_or_root(done))
775 parent = dirname_malloc(done);
779 /* Don't allow this to leave the root dir. */
781 path_startswith(done, root) &&
782 !path_startswith(parent, root))
785 free_and_replace(done, parent);
787 if (flags & CHASE_STEP)
790 fd_parent = openat(fd, "..", O_CLOEXEC|O_NOFOLLOW|O_PATH);
794 if (flags & CHASE_SAFE) {
795 if (fstat(fd_parent, &st) < 0)
798 if (!safe_transition(&previous_stat, &st))
805 fd = TAKE_FD(fd_parent);
810 /* Otherwise let's see what this is. */
811 child = openat(fd, first + n, O_CLOEXEC|O_NOFOLLOW|O_PATH);
814 if (errno == ENOENT &&
815 (flags & CHASE_NONEXISTENT) &&
816 (isempty(todo) || path_is_normalized(todo))) {
818 /* If CHASE_NONEXISTENT is set, and the path does not exist, then that's OK, return
819 * what we got so far. But don't allow this if the remaining path contains "../ or "./"
820 * or something else weird. */
822 /* If done is "/", as first also contains slash at the head, then remove this redundant slash. */
823 if (streq_ptr(done, "/"))
826 if (!strextend(&done, first, todo, NULL))
836 if (fstat(child, &st) < 0)
838 if ((flags & CHASE_SAFE) &&
839 !safe_transition(&previous_stat, &st))
844 if ((flags & CHASE_NO_AUTOFS) &&
845 fd_is_fs_type(child, AUTOFS_SUPER_MAGIC) > 0)
848 if (S_ISLNK(st.st_mode)) {
851 _cleanup_free_ char *destination = NULL;
853 /* This is a symlink, in this case read the destination. But let's make sure we don't follow
854 * symlinks without bounds. */
855 if (--max_follow <= 0)
858 r = readlinkat_malloc(fd, first + n, &destination);
861 if (isempty(destination))
864 if (path_is_absolute(destination)) {
866 /* An absolute destination. Start the loop from the beginning, but use the root
867 * directory as base. */
870 fd = open(root ?: "/", O_CLOEXEC|O_NOFOLLOW|O_PATH);
874 if (flags & CHASE_SAFE) {
875 if (fstat(fd, &st) < 0)
878 if (!safe_transition(&previous_stat, &st))
886 /* Note that we do not revalidate the root, we take it as is. */
895 /* Prefix what's left to do with what we just read, and start the loop again, but
896 * remain in the current directory. */
897 joined = strjoin(destination, todo);
899 joined = strjoin("/", destination, todo);
904 todo = buffer = joined;
906 if (flags & CHASE_STEP)
912 /* If this is not a symlink, then let's just add the name we read to what we already verified. */
914 done = TAKE_PTR(first);
916 /* If done is "/", as first also contains slash at the head, then remove this redundant slash. */
917 if (streq(done, "/"))
920 if (!strextend(&done, first, NULL))
924 /* And iterate again, but go one directory further down. */
930 /* Special case, turn the empty string into "/", to indicate the root directory. */
937 *ret = TAKE_PTR(done);
939 if (flags & CHASE_OPEN) {
940 /* Return the O_PATH fd we currently are looking to the caller. It can translate it to a proper fd by
941 * opening /proc/self/fd/xyz. */
947 if (flags & CHASE_STEP)
956 c = strjoin(strempty(done), todo);
966 int chase_symlinks_and_open(
969 unsigned chase_flags,
973 _cleanup_close_ int path_fd = -1;
974 _cleanup_free_ char *p = NULL;
977 if (chase_flags & CHASE_NONEXISTENT)
980 if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) {
981 /* Shortcut this call if none of the special features of this call are requested */
982 r = open(path, open_flags);
989 path_fd = chase_symlinks(path, root, chase_flags|CHASE_OPEN, ret_path ? &p : NULL);
993 r = fd_reopen(path_fd, open_flags);
998 *ret_path = TAKE_PTR(p);
1003 int chase_symlinks_and_opendir(
1006 unsigned chase_flags,
1010 char procfs_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)];
1011 _cleanup_close_ int path_fd = -1;
1012 _cleanup_free_ char *p = NULL;
1017 if (chase_flags & CHASE_NONEXISTENT)
1020 if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) {
1021 /* Shortcut this call if none of the special features of this call are requested */
1030 path_fd = chase_symlinks(path, root, chase_flags|CHASE_OPEN, ret_path ? &p : NULL);
1034 xsprintf(procfs_path, "/proc/self/fd/%i", path_fd);
1035 d = opendir(procfs_path);
1040 *ret_path = TAKE_PTR(p);
1046 int chase_symlinks_and_stat(
1049 unsigned chase_flags,
1051 struct stat *ret_stat) {
1053 _cleanup_close_ int path_fd = -1;
1054 _cleanup_free_ char *p = NULL;
1059 if (chase_flags & CHASE_NONEXISTENT)
1062 if (empty_or_root(root) && !ret_path && (chase_flags & (CHASE_NO_AUTOFS|CHASE_SAFE)) == 0) {
1063 /* Shortcut this call if none of the special features of this call are requested */
1064 if (stat(path, ret_stat) < 0)
1070 path_fd = chase_symlinks(path, root, chase_flags|CHASE_OPEN, ret_path ? &p : NULL);
1074 if (fstat(path_fd, ret_stat) < 0)
1078 *ret_path = TAKE_PTR(p);
1080 if (chase_flags & CHASE_OPEN)
1081 return TAKE_FD(path_fd);
1086 int access_fd(int fd, int mode) {
1087 char p[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(fd) + 1];
1090 /* Like access() but operates on an already open fd */
1092 xsprintf(p, "/proc/self/fd/%i", fd);
1093 r = access(p, mode);
1100 void unlink_tempfilep(char (*p)[]) {
1101 /* If the file is created with mkstemp(), it will (almost always)
1102 * change the suffix. Treat this as a sign that the file was
1103 * successfully created. We ignore both the rare case where the
1104 * original suffix is used and unlink failures. */
1105 if (!endswith(*p, ".XXXXXX"))
1106 (void) unlink_noerrno(*p);
1109 int unlinkat_deallocate(int fd, const char *name, int flags) {
1110 _cleanup_close_ int truncate_fd = -1;
1114 /* Operates like unlinkat() but also deallocates the file contents if it is a regular file and there's no other
1115 * link to it. This is useful to ensure that other processes that might have the file open for reading won't be
1116 * able to keep the data pinned on disk forever. This call is particular useful whenever we execute clean-up
1117 * jobs ("vacuuming"), where we want to make sure the data is really gone and the disk space released and
1118 * returned to the free pool.
1120 * Deallocation is preferably done by FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE (đ) if supported, which means
1121 * the file won't change size. That's a good thing since we shouldn't needlessly trigger SIGBUS in other
1122 * programs that have mmap()ed the file. (The assumption here is that changing file contents to all zeroes
1123 * underneath those programs is the better choice than simply triggering SIGBUS in them which truncation does.)
1124 * However if hole punching is not implemented in the kernel or file system we'll fall back to normal file
1125 * truncation (đĒ), as our goal of deallocating the data space trumps our goal of being nice to readers (đ).
1127 * Note that we attempt deallocation, but failure to succeed with that is not considered fatal, as long as the
1128 * primary job â to delete the file â is accomplished. */
1130 if ((flags & AT_REMOVEDIR) == 0) {
1131 truncate_fd = openat(fd, name, O_WRONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW|O_NONBLOCK);
1132 if (truncate_fd < 0) {
1134 /* If this failed because the file doesn't exist propagate the error right-away. Also,
1135 * AT_REMOVEDIR wasn't set, and we tried to open the file for writing, which means EISDIR is
1136 * returned when this is a directory but we are not supposed to delete those, hence propagate
1137 * the error right-away too. */
1138 if (IN_SET(errno, ENOENT, EISDIR))
1141 if (errno != ELOOP) /* don't complain if this is a symlink */
1142 log_debug_errno(errno, "Failed to open file '%s' for deallocation, ignoring: %m", name);
1146 if (unlinkat(fd, name, flags) < 0)
1149 if (truncate_fd < 0) /* Don't have a file handle, can't do more âšī¸ */
1152 if (fstat(truncate_fd, &st) < 0) {
1153 log_debug_errno(errno, "Failed to stat file '%s' for deallocation, ignoring.", name);
1157 if (!S_ISREG(st.st_mode) || st.st_blocks == 0 || st.st_nlink > 0)
1160 /* If this is a regular file, it actually took up space on disk and there are no other links it's time to
1161 * punch-hole/truncate this to release the disk space. */
1163 bs = MAX(st.st_blksize, 512);
1164 l = DIV_ROUND_UP(st.st_size, bs) * bs; /* Round up to next block size */
1166 if (fallocate(truncate_fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE, 0, l) >= 0)
1167 return 0; /* Successfully punched a hole! đ */
1169 /* Fall back to truncation */
1170 if (ftruncate(truncate_fd, 0) < 0) {
1171 log_debug_errno(errno, "Failed to truncate file to 0, ignoring: %m");
1178 int fsync_directory_of_file(int fd) {
1179 _cleanup_free_ char *path = NULL, *dn = NULL;
1180 _cleanup_close_ int dfd = -1;
1183 r = fd_verify_regular(fd);
1187 r = fd_get_path(fd, &path);
1189 log_debug_errno(r, "Failed to query /proc/self/fd/%d%s: %m",
1191 r == -EOPNOTSUPP ? ", ignoring" : "");
1193 if (r == -EOPNOTSUPP)
1194 /* If /proc is not available, we're most likely running in some
1195 * chroot environment, and syncing the directory is not very
1196 * important in that case. Let's just silently do nothing. */
1202 if (!path_is_absolute(path))
1205 dn = dirname_malloc(path);
1209 dfd = open(dn, O_RDONLY|O_CLOEXEC|O_DIRECTORY);