77f9fa3b8e
We have similar code in stat-util.[ch] and managing this at a central place almost definitely is the better choice.
272 lines
6.7 KiB
C
272 lines
6.7 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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/***
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This file is part of systemd.
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Copyright 2010-2012 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <dirent.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <linux/magic.h>
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#include <sched.h>
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#include <sys/stat.h>
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#include <sys/statvfs.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include "dirent-util.h"
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#include "fd-util.h"
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#include "fs-util.h"
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#include "macro.h"
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#include "missing.h"
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#include "stat-util.h"
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#include "string-util.h"
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int is_symlink(const char *path) {
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struct stat info;
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assert(path);
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if (lstat(path, &info) < 0)
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return -errno;
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return !!S_ISLNK(info.st_mode);
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}
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int is_dir(const char* path, bool follow) {
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struct stat st;
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int r;
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assert(path);
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if (follow)
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r = stat(path, &st);
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else
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r = lstat(path, &st);
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if (r < 0)
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return -errno;
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return !!S_ISDIR(st.st_mode);
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}
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int is_device_node(const char *path) {
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struct stat info;
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assert(path);
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if (lstat(path, &info) < 0)
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return -errno;
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return !!(S_ISBLK(info.st_mode) || S_ISCHR(info.st_mode));
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}
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int dir_is_empty(const char *path) {
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_cleanup_closedir_ DIR *d;
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struct dirent *de;
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d = opendir(path);
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if (!d)
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return -errno;
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FOREACH_DIRENT(de, d, return -errno)
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return 0;
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return 1;
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}
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bool null_or_empty(struct stat *st) {
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assert(st);
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if (S_ISREG(st->st_mode) && st->st_size <= 0)
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return true;
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/* We don't want to hardcode the major/minor of /dev/null,
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* hence we do a simpler "is this a device node?" check. */
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if (S_ISCHR(st->st_mode) || S_ISBLK(st->st_mode))
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return true;
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return false;
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}
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int null_or_empty_path(const char *fn) {
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struct stat st;
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assert(fn);
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if (stat(fn, &st) < 0)
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return -errno;
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return null_or_empty(&st);
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}
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int null_or_empty_fd(int fd) {
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struct stat st;
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assert(fd >= 0);
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if (fstat(fd, &st) < 0)
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return -errno;
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return null_or_empty(&st);
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}
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int path_is_read_only_fs(const char *path) {
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struct statvfs st;
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assert(path);
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if (statvfs(path, &st) < 0)
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return -errno;
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if (st.f_flag & ST_RDONLY)
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return true;
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/* On NFS, statvfs() might not reflect whether we can actually
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* write to the remote share. Let's try again with
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* access(W_OK) which is more reliable, at least sometimes. */
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if (access(path, W_OK) < 0 && errno == EROFS)
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return true;
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return false;
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}
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int path_is_os_tree(const char *path) {
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int r;
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assert(path);
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/* Does the path exist at all? If not, generate an error immediately. This is useful so that a missing root dir
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* always results in -ENOENT, and we can properly distuingish the case where the whole root doesn't exist from
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* the case where just the os-release file is missing. */
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if (laccess(path, F_OK) < 0)
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return -errno;
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/* We use /usr/lib/os-release as flag file if something is an OS */
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r = chase_symlinks("/usr/lib/os-release", path, CHASE_PREFIX_ROOT, NULL);
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if (r == -ENOENT) {
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/* Also check for the old location in /etc, just in case. */
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r = chase_symlinks("/etc/os-release", path, CHASE_PREFIX_ROOT, NULL);
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if (r == -ENOENT)
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return 0; /* We got nothing */
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}
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if (r < 0)
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return r;
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return 1;
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}
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int files_same(const char *filea, const char *fileb, int flags) {
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struct stat a, b;
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assert(filea);
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assert(fileb);
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if (fstatat(AT_FDCWD, filea, &a, flags) < 0)
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return -errno;
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if (fstatat(AT_FDCWD, fileb, &b, flags) < 0)
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return -errno;
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return a.st_dev == b.st_dev &&
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a.st_ino == b.st_ino;
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}
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bool is_fs_type(const struct statfs *s, statfs_f_type_t magic_value) {
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assert(s);
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assert_cc(sizeof(statfs_f_type_t) >= sizeof(s->f_type));
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return F_TYPE_EQUAL(s->f_type, magic_value);
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}
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int fd_is_fs_type(int fd, statfs_f_type_t magic_value) {
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struct statfs s;
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if (fstatfs(fd, &s) < 0)
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return -errno;
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return is_fs_type(&s, magic_value);
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}
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int path_is_fs_type(const char *path, statfs_f_type_t magic_value) {
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_cleanup_close_ int fd = -1;
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fd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_PATH);
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if (fd < 0)
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return -errno;
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return fd_is_fs_type(fd, magic_value);
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}
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bool is_temporary_fs(const struct statfs *s) {
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return is_fs_type(s, TMPFS_MAGIC) ||
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is_fs_type(s, RAMFS_MAGIC);
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}
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bool is_network_fs(const struct statfs *s) {
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return is_fs_type(s, CIFS_MAGIC_NUMBER) ||
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is_fs_type(s, CODA_SUPER_MAGIC) ||
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is_fs_type(s, NCP_SUPER_MAGIC) ||
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is_fs_type(s, NFS_SUPER_MAGIC) ||
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is_fs_type(s, SMB_SUPER_MAGIC) ||
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is_fs_type(s, V9FS_MAGIC) ||
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is_fs_type(s, AFS_SUPER_MAGIC) ||
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is_fs_type(s, OCFS2_SUPER_MAGIC);
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}
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int fd_is_temporary_fs(int fd) {
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struct statfs s;
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if (fstatfs(fd, &s) < 0)
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return -errno;
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return is_temporary_fs(&s);
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}
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int fd_is_network_fs(int fd) {
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struct statfs s;
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if (fstatfs(fd, &s) < 0)
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return -errno;
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return is_network_fs(&s);
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}
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int fd_is_network_ns(int fd) {
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int r;
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r = fd_is_fs_type(fd, NSFS_MAGIC);
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if (r <= 0)
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return r;
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if (ioctl(fd, NS_GET_NSTYPE) < 0)
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return -errno;
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return r == CLONE_NEWNET;
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}
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int path_is_temporary_fs(const char *path) {
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_cleanup_close_ int fd = -1;
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fd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_PATH);
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if (fd < 0)
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return -errno;
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return fd_is_temporary_fs(fd);
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}
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