X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fshared%2Fpath-util.c;h=a01475a6144e94e40b712bafe52ea96ca868a6d6;hp=00d2d44993d3711adfc2b244e994360d1f2a8912;hb=9c9d36f9678578d2d321cb18ff31b2e1c224a63a;hpb=2695c5c44e028d1bc07404baf3357e5a6017fc57
diff --git a/src/shared/path-util.c b/src/shared/path-util.c
index 00d2d4499..a01475a61 100644
--- a/src/shared/path-util.c
+++ b/src/shared/path-util.c
@@ -19,15 +19,12 @@
along with systemd; If not, see .
***/
-#include
#include
#include
#include
#include
-#include
#include
#include
-#include
#include
#include "macro.h"
@@ -403,12 +400,18 @@ char* path_startswith(const char *path, const char *prefix) {
}
}
-bool path_equal(const char *a, const char *b) {
+int path_compare(const char *a, const char *b) {
+ int d;
+
assert(a);
assert(b);
- if ((a[0] == '/') != (b[0] == '/'))
- return false;
+ /* A relative path and an abolute path must not compare as equal.
+ * Which one is sorted before the other does not really matter.
+ * Here a relative path is ordered before an absolute path. */
+ d = (a[0] == '/') - (b[0] == '/');
+ if (d)
+ return d;
for (;;) {
size_t j, k;
@@ -417,25 +420,40 @@ bool path_equal(const char *a, const char *b) {
b += strspn(b, "/");
if (*a == 0 && *b == 0)
- return true;
+ return 0;
- if (*a == 0 || *b == 0)
- return false;
+ /* Order prefixes first: "/foo" before "/foo/bar" */
+ if (*a == 0)
+ return -1;
+ if (*b == 0)
+ return 1;
j = strcspn(a, "/");
k = strcspn(b, "/");
- if (j != k)
- return false;
+ /* Alphabetical sort: "/foo/aaa" before "/foo/b" */
+ d = memcmp(a, b, MIN(j, k));
+ if (d)
+ return (d > 0) - (d < 0); /* sign of d */
- if (memcmp(a, b, j) != 0)
- return false;
+ /* Sort "/foo/a" before "/foo/aaa" */
+ d = (j > k) - (j < k); /* sign of (j - k) */
+ if (d)
+ return d;
a += j;
b += k;
}
}
+bool path_equal(const char *a, const char *b) {
+ return path_compare(a, b) == 0;
+}
+
+bool path_equal_or_files_same(const char *a, const char *b) {
+ return path_equal(a, b) || files_same(a, b) > 0;
+}
+
char* path_join(const char *root, const char *path, const char *rest) {
assert(path);
@@ -452,23 +470,20 @@ char* path_join(const char *root, const char *path, const char *rest) {
NULL);
}
-int path_is_mount_point(const char *t, bool allow_symlink) {
-
- union file_handle_union h = FILE_HANDLE_INIT;
+int fd_is_mount_point(int fd) {
+ union file_handle_union h = FILE_HANDLE_INIT, h_parent = FILE_HANDLE_INIT;
int mount_id = -1, mount_id_parent = -1;
- _cleanup_free_ char *parent = NULL;
+ bool nosupp = false;
struct stat a, b;
int r;
- bool nosupp = false;
+
+ 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 */
- if (path_equal(t, "/"))
- return 1;
-
- r = name_to_handle_at(AT_FDCWD, t, &h.handle, &mount_id, allow_symlink ? AT_SYMLINK_FOLLOW : 0);
+ r = name_to_handle_at(fd, "", &h.handle, &mount_id, AT_EMPTY_PATH);
if (r < 0) {
if (errno == ENOSYS)
/* This kernel does not support name_to_handle_at()
@@ -476,65 +491,81 @@ int path_is_mount_point(const char *t, bool allow_symlink) {
goto fallback;
else if (errno == EOPNOTSUPP)
/* This kernel or file system does not support
- * name_to_handle_at(), hence fallback to the
+ * 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 if (errno == ENOENT)
- return 0;
else
return -errno;
}
- r = path_get_parent(t, &parent);
- if (r < 0)
- return r;
-
- h.handle.handle_bytes = MAX_HANDLE_SZ;
- r = name_to_handle_at(AT_FDCWD, parent, &h.handle, &mount_id_parent, AT_SYMLINK_FOLLOW);
- if (r < 0)
- if (errno == EOPNOTSUPP)
+ r = name_to_handle_at(fd, "..", &h_parent.handle, &mount_id_parent, 0);
+ 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;
else
- /* The parent can't do name_to_handle_at() but
- * the directory we are interested in can?
- * Or the other way around?
+ /* 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
+ } else
return -errno;
- else
- return mount_id != mount_id_parent;
+ } else if (nosupp)
+ /* 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. */
+ return 1;
+ 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. */
-fallback:
- if (allow_symlink)
- r = stat(t, &a);
- else
- r = lstat(t, &a);
+ 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;
- if (r < 0) {
- if (errno == ENOENT)
- return 0;
-
- return -errno;
+ return mount_id != mount_id_parent;
}
- free(parent);
- parent = NULL;
-
- r = path_get_parent(t, &parent);
+fallback:
+ r = fstatat(fd, "", &a, AT_EMPTY_PATH);
if (r < 0)
- return r;
+ return -errno;
- r = stat(parent, &b);
+ r = fstatat(fd, "..", &b, 0);
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;
}
+int path_is_mount_point(const char *t, bool allow_symlink) {
+ _cleanup_close_ int fd = -1;
+
+ 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));
+ if (fd < 0)
+ return -errno;
+
+ return fd_is_mount_point(fd);
+}
+
int path_is_read_only_fs(const char *path) {
struct statvfs st;
@@ -560,14 +591,14 @@ int path_is_os_tree(const char *path) {
int r;
/* We use /usr/lib/os-release as flag file if something is an OS */
- p = strappenda(path, "/usr/lib/os-release");
+ p = strjoina(path, "/usr/lib/os-release");
r = access(p, F_OK);
if (r >= 0)
return 1;
/* Also check for the old location in /etc, just in case. */
- p = strappenda(path, "/etc/os-release");
+ p = strjoina(path, "/etc/os-release");
r = access(p, F_OK);
return r >= 0;
@@ -665,7 +696,7 @@ int fsck_exists(const char *fstype) {
const char *checker;
int r;
- checker = strappenda("fsck.", fstype);
+ checker = strjoina("fsck.", fstype);
r = find_binary(checker, true, &p);
if (r < 0)