diff options
Diffstat (limited to 'shared/systemd/src/basic/stat-util.c')
| -rw-r--r-- | shared/systemd/src/basic/stat-util.c | 433 |
1 files changed, 433 insertions, 0 deletions
diff --git a/shared/systemd/src/basic/stat-util.c b/shared/systemd/src/basic/stat-util.c new file mode 100644 index 00000000..686adaf1 --- /dev/null +++ b/shared/systemd/src/basic/stat-util.c @@ -0,0 +1,433 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#include "nm-sd-adapt-shared.h" + +#include <dirent.h> +#include <errno.h> +#include <fcntl.h> +#include <linux/magic.h> +#include <sched.h> +#include <sys/stat.h> +#include <sys/statvfs.h> +#include <sys/types.h> +#include <unistd.h> + +#include "alloc-util.h" +#include "dirent-util.h" +#include "fd-util.h" +#include "fs-util.h" +#include "macro.h" +#include "missing.h" +#include "parse-util.h" +#include "stat-util.h" +#include "string-util.h" + +#if 0 /* NM_IGNORED */ +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_dir_fd(int fd) { + struct stat st; + + if (fstat(fd, &st) < 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_at(int dir_fd, const char *path) { + _cleanup_close_ int fd = -1; + _cleanup_closedir_ DIR *d = NULL; + struct dirent *de; + + if (path) + fd = openat(dir_fd, path, O_RDONLY|O_DIRECTORY|O_CLOEXEC); + else + fd = fcntl(fd, F_DUPFD_CLOEXEC, 3); + if (fd < 0) + return -errno; + + d = fdopendir(fd); + if (!d) + return -errno; + fd = -1; + + 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 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_is_fs_type(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_is_fs_type(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_is_fs_type(fd, magic_value); +} + +bool is_temporary_fs(const struct statfs *s) { + return is_fs_type(s, TMPFS_MAGIC) || + is_fs_type(s, RAMFS_MAGIC); +} + +bool is_network_fs(const struct statfs *s) { + return is_fs_type(s, CIFS_MAGIC_NUMBER) || + is_fs_type(s, CODA_SUPER_MAGIC) || + is_fs_type(s, NCP_SUPER_MAGIC) || + is_fs_type(s, NFS_SUPER_MAGIC) || + is_fs_type(s, SMB_SUPER_MAGIC) || + is_fs_type(s, V9FS_MAGIC) || + is_fs_type(s, AFS_SUPER_MAGIC) || + is_fs_type(s, OCFS2_SUPER_MAGIC); +} + +int fd_is_temporary_fs(int fd) { + struct statfs s; + + if (fstatfs(fd, &s) < 0) + return -errno; + + return is_temporary_fs(&s); +} + +int fd_is_network_fs(int fd) { + struct statfs s; + + if (fstatfs(fd, &s) < 0) + return -errno; + + return is_network_fs(&s); +} + +int fd_is_network_ns(int fd) { + struct statfs s; + int r; + + /* Checks whether the specified file descriptor refers to a network namespace. On old kernels there's no nice + * way to detect that, hence on those we'll return a recognizable error (EUCLEAN), so that callers can handle + * this somewhat nicely. + * + * This function returns > 0 if the fd definitely refers to a network namespace, 0 if it definitely does not + * refer to a network namespace, -EUCLEAN if we can't determine, and other negative error codes on error. */ + + if (fstatfs(fd, &s) < 0) + return -errno; + + if (!is_fs_type(&s, NSFS_MAGIC)) { + /* On really old kernels, there was no "nsfs", and network namespace sockets belonged to procfs + * instead. Handle that in a somewhat smart way. */ + + if (is_fs_type(&s, PROC_SUPER_MAGIC)) { + struct statfs t; + + /* OK, so it is procfs. Let's see if our own network namespace is procfs, too. If so, then the + * passed fd might refer to a network namespace, but we can't know for sure. In that case, + * return a recognizable error. */ + + if (statfs("/proc/self/ns/net", &t) < 0) + return -errno; + + if (s.f_type == t.f_type) + return -EUCLEAN; /* It's possible, we simply don't know */ + } + + return 0; /* No! */ + } + + r = ioctl(fd, NS_GET_NSTYPE); + if (r < 0) { + if (errno == ENOTTY) /* Old kernels didn't know this ioctl, let's also return a recognizable error in that case */ + return -EUCLEAN; + + return -errno; + } + + return r == CLONE_NEWNET; +} + +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); +} +#endif /* NM_IGNORED */ + +int stat_verify_regular(const struct stat *st) { + assert(st); + + /* Checks whether the specified stat() structure refers to a regular file. If not returns an appropriate error + * code. */ + + if (S_ISDIR(st->st_mode)) + return -EISDIR; + + if (S_ISLNK(st->st_mode)) + return -ELOOP; + + if (!S_ISREG(st->st_mode)) + return -EBADFD; + + return 0; +} + +int fd_verify_regular(int fd) { + struct stat st; + + assert(fd >= 0); + + if (fstat(fd, &st) < 0) + return -errno; + + return stat_verify_regular(&st); +} + +#if 0 /* NM_IGNORED */ +int stat_verify_directory(const struct stat *st) { + assert(st); + + if (S_ISLNK(st->st_mode)) + return -ELOOP; + + if (!S_ISDIR(st->st_mode)) + return -ENOTDIR; + + return 0; +} + +int fd_verify_directory(int fd) { + struct stat st; + + assert(fd >= 0); + + if (fstat(fd, &st) < 0) + return -errno; + + return stat_verify_directory(&st); +} + +int device_path_make_major_minor(mode_t mode, dev_t devno, char **ret) { + const char *t; + + /* Generates the /dev/{char|block}/MAJOR:MINOR path for a dev_t */ + + if (S_ISCHR(mode)) + t = "char"; + else if (S_ISBLK(mode)) + t = "block"; + else + return -ENODEV; + + if (asprintf(ret, "/dev/%s/%u:%u", t, major(devno), minor(devno)) < 0) + return -ENOMEM; + + return 0; +} + +int device_path_make_canonical(mode_t mode, dev_t devno, char **ret) { + _cleanup_free_ char *p = NULL; + int r; + + /* Finds the canonical path for a device, i.e. resolves the /dev/{char|block}/MAJOR:MINOR path to the end. */ + + assert(ret); + + if (major(devno) == 0 && minor(devno) == 0) { + char *s; + + /* A special hack to make sure our 'inaccessible' device nodes work. They won't have symlinks in + * /dev/block/ and /dev/char/, hence we handle them specially here. */ + + if (S_ISCHR(mode)) + s = strdup("/run/systemd/inaccessible/chr"); + else if (S_ISBLK(mode)) + s = strdup("/run/systemd/inaccessible/blk"); + else + return -ENODEV; + + if (!s) + return -ENOMEM; + + *ret = s; + return 0; + } + + r = device_path_make_major_minor(mode, devno, &p); + if (r < 0) + return r; + + return chase_symlinks(p, NULL, 0, ret); +} + +int device_path_parse_major_minor(const char *path, mode_t *ret_mode, dev_t *ret_devno) { + mode_t mode; + dev_t devno; + int r; + + /* Tries to extract the major/minor directly from the device path if we can. Handles /dev/block/ and /dev/char/ + * paths, as well out synthetic inaccessible device nodes. Never goes to disk. Returns -ENODEV if the device + * path cannot be parsed like this. */ + + if (path_equal(path, "/run/systemd/inaccessible/chr")) { + mode = S_IFCHR; + devno = makedev(0, 0); + } else if (path_equal(path, "/run/systemd/inaccessible/blk")) { + mode = S_IFBLK; + devno = makedev(0, 0); + } else { + const char *w; + + w = path_startswith(path, "/dev/block/"); + if (w) + mode = S_IFBLK; + else { + w = path_startswith(path, "/dev/char/"); + if (!w) + return -ENODEV; + + mode = S_IFCHR; + } + + r = parse_dev(w, &devno); + if (r < 0) + return r; + } + + if (ret_mode) + *ret_mode = mode; + if (ret_devno) + *ret_devno = devno; + + return 0; +} +#endif /* NM_IGNORED */ |