322 lines
7.8 KiB
C
322 lines
7.8 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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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_dir_fd(int fd) {
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struct stat st;
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if (fstat(fd, &st) < 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 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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struct statfs s;
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int r;
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/* Checks whether the specified file descriptor refers to a network namespace. On old kernels there's no nice
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* way to detect that, hence on those we'll return a recognizable error (EUCLEAN), so that callers can handle
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* this somewhat nicely.
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*
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* This function returns > 0 if the fd definitely refers to a network namespace, 0 if it definitely does not
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* refer to a network namespace, -EUCLEAN if we can't determine, and other negative error codes on error. */
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if (fstatfs(fd, &s) < 0)
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return -errno;
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if (!is_fs_type(&s, NSFS_MAGIC)) {
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/* On really old kernels, there was no "nsfs", and network namespace sockets belonged to procfs
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* instead. Handle that in a somewhat smart way. */
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if (is_fs_type(&s, PROC_SUPER_MAGIC)) {
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struct statfs t;
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/* OK, so it is procfs. Let's see if our own network namespace is procfs, too. If so, then the
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* passed fd might refer to a network namespace, but we can't know for sure. In that case,
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* return a recognizable error. */
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if (statfs("/proc/self/ns/net", &t) < 0)
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return -errno;
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if (s.f_type == t.f_type)
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return -EUCLEAN; /* It's possible, we simply don't know */
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}
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return 0; /* No! */
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}
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r = ioctl(fd, NS_GET_NSTYPE);
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if (r < 0) {
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if (errno == ENOTTY) /* Old kernels didn't know this ioctl, let's also return a recognizable error in that case */
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return -EUCLEAN;
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return -errno;
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}
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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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int stat_verify_regular(const struct stat *st) {
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assert(st);
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/* Checks whether the specified stat() structure refers to a regular file. If not returns an appropriate error
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* code. */
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if (S_ISDIR(st->st_mode))
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return -EISDIR;
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if (S_ISLNK(st->st_mode))
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return -ELOOP;
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if (!S_ISREG(st->st_mode))
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return -EBADFD;
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return 0;
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}
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int fd_verify_regular(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 stat_verify_regular(&st);
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}
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int stat_verify_directory(const struct stat *st) {
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assert(st);
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if (S_ISLNK(st->st_mode))
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return -ELOOP;
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if (!S_ISDIR(st->st_mode))
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return -ENOTDIR;
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return 0;
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}
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int fd_verify_directory(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 stat_verify_directory(&st);
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}
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