return safe_atoi(p, mnt_id);
}
-int fd_is_mount_point(int fd) {
+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 = false;
+ 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
*
* 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 the
+ * 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
* subvolumes have different st_dev, even though they aren't
* real mounts of their own. */
- r = name_to_handle_at(fd, "", &h.handle, &mount_id, AT_EMPTY_PATH);
+ 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()
return -errno;
}
- r = name_to_handle_at(fd, "..", &h_parent.handle, &mount_id_parent, 0);
+ r = name_to_handle_at(fd, "", &h_parent.handle, &mount_id_parent, AT_EMPTY_PATH);
if (r < 0) {
if (errno == EOPNOTSUPP) {
if (nosupp)
return mount_id != mount_id_parent;
fallback_fdinfo:
- r = fd_fdinfo_mnt_id(fd, "", AT_EMPTY_PATH, &mount_id);
+ 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, "..", 0, &mount_id_parent);
+ r = fd_fdinfo_mnt_id(fd, "", AT_EMPTY_PATH, &mount_id_parent);
if (r < 0)
return r;
check_st_dev = false;
fallback_fstat:
- if (fstatat(fd, "", &a, AT_EMPTY_PATH) < 0)
+ /* 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, 0) < 0)
+ if (fstatat(fd, "", &b, AT_EMPTY_PATH) < 0)
return -errno;
/* A directory with same device and inode as its parent? Must
return check_st_dev && (a.st_dev != b.st_dev);
}
-int path_is_mount_point(const char *t, bool allow_symlink) {
+/* 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;
+ int r;
assert(t);
if (path_equal(t, "/"))
return 1;
- fd = openat(AT_FDCWD, t, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|(allow_symlink ? 0 : O_PATH));
+ /* 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;
+ }
+
+ r = path_get_parent(canonical ?: t, &parent);
+ if (r < 0)
+ return r;
+
+ 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);
+ return fd_is_mount_point(fd, basename(canonical ?: t), flags);
}
int path_is_read_only_fs(const char *path) {
return 0;
}
+
+char *prefix_root(const char *root, const char *path) {
+ char *n, *p;
+ size_t l;
+
+ /* If root is passed, prefixes path with it. Otherwise returns
+ * it as is. */
+
+ assert(path);
+
+ /* First, drop duplicate prefixing slashes from the path */
+ while (path[0] == '/' && path[1] == '/')
+ path++;
+
+ if (isempty(root) || path_equal(root, "/"))
+ return strdup(path);
+
+ l = strlen(root) + 1 + strlen(path) + 1;
+
+ n = new(char, l);
+ if (!n)
+ return NULL;
+
+ p = stpcpy(n, root);
+
+ while (p > n && p[-1] == '/')
+ p--;
+
+ if (path[0] != '/')
+ *(p++) = '/';
+
+ strcpy(p, path);
+ return n;
+}