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path-util: make sure fd_is_mount_point() returns true for root directory

This commit is contained in:
Lennart Poettering 2015-04-05 11:12:16 +02:00
parent 9e9b663aae
commit 05d990efd7
1 changed files with 22 additions and 4 deletions
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26
src/shared/path-util.c
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@ -471,12 +471,14 @@ char* path_join(const char *root, const char *path, const char *rest) {
}
int fd_is_mount_point(int fd) {
union file_handle_union h = FILE_HANDLE_INIT;
union file_handle_union h = FILE_HANDLE_INIT, h_parent = FILE_HANDLE_INIT;
int mount_id = -1, mount_id_parent = -1;
bool nosupp = false;
struct stat a, b;
int r;
assert(fd >= 0);
/* We are not actually interested in the file handles, but
* name_to_handle_at() also passes us the mount ID, hence use
* it but throw the handle away */
@ -500,8 +502,7 @@ int fd_is_mount_point(int fd) {
return -errno;
}
h.handle.handle_bytes = MAX_HANDLE_SZ;
r = name_to_handle_at(fd, "..", &h.handle, &mount_id_parent, 0);
r = name_to_handle_at(fd, "..", &h_parent.handle, &mount_id_parent, 0);
if (r < 0) {
if (errno == EOPNOTSUPP) {
if (nosupp)
@ -520,8 +521,19 @@ int fd_is_mount_point(int fd) {
* directory we are interested in can't? If so, it
* must be a mount point. */
return 1;
else
else {
/* 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:
r = fstatat(fd, "", &a, AT_EMPTY_PATH);
@ -536,6 +548,12 @@ fallback:
if (r < 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 a.st_dev != b.st_dev;
}