blockdev-util: add fd-based APIs for getting backing block device for file

poettering · poettering · commit bcf8fc267f90 · 2021-07-08T14:49:02.000+02:00
diff --git a/src/shared/blockdev-util.c b/src/shared/blockdev-util.c
@@ -182,26 +182,39 @@ int block_get_originating(dev_t dt, dev_t *ret) {
         return 1;
 }
 
-int get_block_device_harder(const char *path, dev_t *ret) {
+int get_block_device_harder_fd(int fd, dev_t *ret) {
         int r;
 
-        assert(path);
+        assert(fd >= 0);
         assert(ret);
 
         /* Gets the backing block device for a file system, and handles LUKS encrypted file systems, looking for its
          * immediate parent, if there is one. */
 
-        r = get_block_device(path, ret);
+        r = get_block_device_fd(fd, ret);
         if (r <= 0)
                 return r;
 
         r = block_get_originating(*ret, ret);
         if (r < 0)
-                log_debug_errno(r, "Failed to chase block device '%s', ignoring: %m", path);
+                log_debug_errno(r, "Failed to chase block device, ignoring: %m");
 
         return 1;
 }
 
+int get_block_device_harder(const char *path, dev_t *ret) {
+        _cleanup_close_ int fd = -1;
+
+        assert(path);
+        assert(ret);
+
+        fd = open(path, O_RDONLY|O_NOFOLLOW|O_CLOEXEC);
+        if (fd < 0)
+                return -errno;
+
+        return get_block_device_harder_fd(fd, ret);
+}
+
 int lock_whole_block_device(dev_t devt, int operation) {
         _cleanup_free_ char *whole_node = NULL;
         _cleanup_close_ int lock_fd = -1;
diff --git a/src/shared/blockdev-util.h b/src/shared/blockdev-util.h
@@ -18,6 +18,7 @@ int block_get_originating(dev_t d, dev_t *ret);
 int get_block_device_fd(int fd, dev_t *ret);
 int get_block_device(const char *path, dev_t *dev);
 
+int get_block_device_harder_fd(int fd, dev_t *dev);
 int get_block_device_harder(const char *path, dev_t *dev);
 
 int lock_whole_block_device(dev_t devt, int operation);
