util-lib: move mount related utility calls to mount-util.[ch]

1 files changed, 0 insertions, 199 deletions

diff --git a/src/basic/path-util.c b/src/basic/path-util.c
index 7abb3a7b9e..b1cab7356c 100644
--- a/src/basic/path-util.c
+++ b/src/basic/path-util.c
@@ -454,205 +454,6 @@ char* path_join(const char *root, const char *path, const char *rest) {
                                NULL);
 }
 
-static int fd_fdinfo_mnt_id(int fd, const char *filename, int flags, int *mnt_id) {
-        char path[strlen("/proc/self/fdinfo/") + DECIMAL_STR_MAX(int)];
-        _cleanup_free_ char *fdinfo = NULL;
-        _cleanup_close_ int subfd = -1;
-        char *p;
-        int r;
-
-        if ((flags & AT_EMPTY_PATH) && isempty(filename))
-                xsprintf(path, "/proc/self/fdinfo/%i", fd);
-        else {
-                subfd = openat(fd, filename, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_PATH);
-                if (subfd < 0)
-                        return -errno;
-
-                xsprintf(path, "/proc/self/fdinfo/%i", subfd);
-        }
-
-        r = read_full_file(path, &fdinfo, NULL);
-        if (r == -ENOENT) /* The fdinfo directory is a relatively new addition */
-                return -EOPNOTSUPP;
-        if (r < 0)
-                return -errno;
-
-        p = startswith(fdinfo, "mnt_id:");
-        if (!p) {
-                p = strstr(fdinfo, "\nmnt_id:");
-                if (!p) /* The mnt_id field is a relatively new addition */
-                        return -EOPNOTSUPP;
-
-                p += 8;
-        }
-
-        p += strspn(p, WHITESPACE);
-        p[strcspn(p, WHITESPACE)] = 0;
-
-        return safe_atoi(p, mnt_id);
-}
-
-int fd_is_mount_point(int fd, const char *filename, int flags) {
-        union file_handle_union h = FILE_HANDLE_INIT, h_parent = FILE_HANDLE_INIT;
-        int mount_id = -1, mount_id_parent = -1;
-        bool nosupp = false, check_st_dev = true;
-        struct stat a, b;
-        int r;
-
-        assert(fd >= 0);
-        assert(filename);
-
-        /* First we will try the name_to_handle_at() syscall, which
-         * tells us the mount id and an opaque file "handle". It is
-         * not supported everywhere though (kernel compile-time
-         * option, not all file systems are hooked up). If it works
-         * the mount id is usually good enough to tell us whether
-         * something is a mount point.
-         *
-         * If that didn't work we will try to read the mount id from
-         * /proc/self/fdinfo/<fd>. This is almost as good as
-         * name_to_handle_at(), however, does not return the
-         * opaque file handle. The opaque file handle is pretty useful
-         * to detect the root directory, which we should always
-         * consider a mount point. Hence we use this only as
-         * fallback. Exporting the mnt_id in fdinfo is a pretty recent
-         * kernel addition.
-         *
-         * As last fallback we do traditional fstat() based st_dev
-         * comparisons. This is how things were traditionally done,
-         * but unionfs breaks breaks this since it exposes file
-         * systems with a variety of st_dev reported. Also, btrfs
-         * subvolumes have different st_dev, even though they aren't
-         * real mounts of their own. */
-
-        r = name_to_handle_at(fd, filename, &h.handle, &mount_id, flags);
-        if (r < 0) {
-                if (errno == ENOSYS)
-                        /* This kernel does not support name_to_handle_at()
-                         * fall back to simpler logic. */
-                        goto fallback_fdinfo;
-                else if (errno == EOPNOTSUPP)
-                        /* This kernel or file system does not support
-                         * name_to_handle_at(), hence let's see if the
-                         * upper fs supports it (in which case it is a
-                         * mount point), otherwise fallback to the
-                         * traditional stat() logic */
-                        nosupp = true;
-                else
-                        return -errno;
-        }
-
-        r = name_to_handle_at(fd, "", &h_parent.handle, &mount_id_parent, AT_EMPTY_PATH);
-        if (r < 0) {
-                if (errno == EOPNOTSUPP) {
-                        if (nosupp)
-                                /* Neither parent nor child do name_to_handle_at()?
-                                   We have no choice but to fall back. */
-                                goto fallback_fdinfo;
-                        else
-                                /* The parent can't do name_to_handle_at() but the
-                                 * directory we are interested in can?
-                                 * If so, it must be a mount point. */
-                                return 1;
-                } else
-                        return -errno;
-        }
-
-        /* The parent can do name_to_handle_at() but the
-         * directory we are interested in can't? If so, it
-         * must be a mount point. */
-        if (nosupp)
-                return 1;
-
-        /* If the file handle for the directory we are
-         * interested in and its parent are identical, we
-         * assume this is the root directory, which is a mount
-         * point. */
-
-        if (h.handle.handle_bytes == h_parent.handle.handle_bytes &&
-            h.handle.handle_type == h_parent.handle.handle_type &&
-            memcmp(h.handle.f_handle, h_parent.handle.f_handle, h.handle.handle_bytes) == 0)
-                return 1;
-
-        return mount_id != mount_id_parent;
-
-fallback_fdinfo:
-        r = fd_fdinfo_mnt_id(fd, filename, flags, &mount_id);
-        if (r == -EOPNOTSUPP)
-                goto fallback_fstat;
-        if (r < 0)
-                return r;
-
-        r = fd_fdinfo_mnt_id(fd, "", AT_EMPTY_PATH, &mount_id_parent);
-        if (r < 0)
-                return r;
-
-        if (mount_id != mount_id_parent)
-                return 1;
-
-        /* Hmm, so, the mount ids are the same. This leaves one
-         * special case though for the root file system. For that,
-         * let's see if the parent directory has the same inode as we
-         * are interested in. Hence, let's also do fstat() checks now,
-         * too, but avoid the st_dev comparisons, since they aren't
-         * that useful on unionfs mounts. */
-        check_st_dev = false;
-
-fallback_fstat:
-        /* yay for fstatat() taking a different set of flags than the other
-         * _at() above */
-        if (flags & AT_SYMLINK_FOLLOW)
-                flags &= ~AT_SYMLINK_FOLLOW;
-        else
-                flags |= AT_SYMLINK_NOFOLLOW;
-        if (fstatat(fd, filename, &a, flags) < 0)
-                return -errno;
-
-        if (fstatat(fd, "", &b, AT_EMPTY_PATH) < 0)
-                return -errno;
-
-        /* A directory with same device and inode as its parent? Must
-         * be the root directory */
-        if (a.st_dev == b.st_dev &&
-            a.st_ino == b.st_ino)
-                return 1;
-
-        return check_st_dev && (a.st_dev != b.st_dev);
-}
-
-/* flags can be AT_SYMLINK_FOLLOW or 0 */
-int path_is_mount_point(const char *t, int flags) {
-        _cleanup_close_ int fd = -1;
-        _cleanup_free_ char *canonical = NULL, *parent = NULL;
-
-        assert(t);
-
-        if (path_equal(t, "/"))
-                return 1;
-
-        /* we need to resolve symlinks manually, we can't just rely on
-         * fd_is_mount_point() to do that for us; if we have a structure like
-         * /bin -> /usr/bin/ and /usr is a mount point, then the parent that we
-         * look at needs to be /usr, not /. */
-        if (flags & AT_SYMLINK_FOLLOW) {
-                canonical = canonicalize_file_name(t);
-                if (!canonical)
-                        return -errno;
-
-                t = canonical;
-        }
-
-        parent = dirname_malloc(t);
-        if (!parent)
-                return -ENOMEM;
-
-        fd = openat(AT_FDCWD, parent, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_PATH);
-        if (fd < 0)
-                return -errno;
-
-        return fd_is_mount_point(fd, basename(t), flags);
-}
-
 int path_is_read_only_fs(const char *path) {
         struct statvfs st;