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