diff --git a/tools.c b/tools.c
index 67723c0..d6229da 100644
--- a/tools.c
+++ b/tools.c
@@ -656,10 +656,12 @@ int string_array_length(char ** a)
 	return i;
 }
 
-int do_losetup(char * device, char * target)
+/* setup loop device from file descriptor targfd */
+int do_losetup_fd(char *device, int targfd, const char *name)
 {
-	int i, loopfd, targfd;
+	int i, loopfd;
 	struct loop_info loopInfo;
+	memset(&loopInfo, 0, sizeof(loopInfo));
 
 	my_insmod("loop", NULL);
 	/* wait for udev's dust settles down */
@@ -670,19 +672,10 @@ int do_losetup(char * device, char * target)
 		return -1;
 	}
 
-	targfd = open( target, O_RDONLY );
-	if ( targfd < 0 )
-	{
-		log_message( "losetup: error opening %s: %s", target, strerror(errno) );
-		close( loopfd );
-		return -1;
-	}
-
 	if ( ioctl(loopfd, LOOP_SET_FD, targfd) < 0 )
 	{
 		log_message( "losetup: error setting up loopback device: %s", strerror(errno) );
 		close( loopfd );
-		close( targfd );
 		return -1;
 	}
 	/* Note: LOOP_SET_FD triggers change event. While processing it
@@ -693,18 +686,19 @@ int do_losetup(char * device, char * target)
 	 */
 	udev_settle();
 
-	memset(&loopInfo, 0, sizeof(loopInfo));
-	strcpy(loopInfo.lo_name, target);
+	if (name) {
+		strcpy(loopInfo.lo_name, name);
 
-	if ( ioctl(loopfd, LOOP_SET_STATUS, &loopInfo) < 0 )
-		log_message( "losetup: error setting up loopback device: %s", strerror(errno) );
+		if ( ioctl(loopfd, LOOP_SET_STATUS, &loopInfo) < 0 )
+			log_message( "losetup: error setting up loopback device: %s", strerror(errno) );
 
-	/* Same here: LOOP_SET_STATUS triggers change event, give udev
-	 * a chance to process it without concurrent access to the loop
-	 * device. In other words, prevent the caller of this function
-	 * from mounting the device while udev still running blkid on it
-	 */
-	udev_settle();
+		/* Same here: LOOP_SET_STATUS triggers change event, give udev
+		 * a chance to process it without concurrent access to the loop
+		 * device. In other words, prevent the caller of this function
+		 * from mounting the device while udev still running blkid on it
+		 */
+		udev_settle();
+	}
 
 	close( loopfd );
 	/* udev might be monitoring loopback device (with fanotify) and
@@ -713,6 +707,20 @@ int do_losetup(char * device, char * target)
 	 * (which is going to mount the newly configured loopback device)
 	 */
 	udev_settle();
-	close( targfd );
 	return 0;
 }
+
+int do_losetup(char * device, char * target)
+{
+	int ret = 0, targfd;
+	targfd = open( target, O_RDONLY );
+	if ( targfd < 0 )
+	{
+		log_message( "losetup: error opening %s: %s", target, strerror(errno) );
+		return -1;
+	}
+	ret = do_losetup_fd(device, targfd, target);
+	close(targfd);
+	return ret;
+}
+
diff --git a/tools.h b/tools.h
index 4b2cf32..2f414d6 100644
--- a/tools.h
+++ b/tools.h
@@ -44,6 +44,19 @@ int pass_env(int);
 char ** list_directory(char * direct);
 int string_array_length(char ** a);
 int do_losetup(char * device, char * target);
+/**
+ * Setup a loopback device backed by fd.
+ *
+ * @param device path to loopback device
+ * @param fd backing file descriptor
+ * @param name for pretty output from losetup, typically name of the backing file.
+ * @return 0 on success, otherwise -1
+ *
+ * @note: should be used instead of do_losetup for anonymous files,
+ * i.e. ones created by memfd_create, open(O_TMPFILE), etc
+ */
+int do_losetup_fd(char *device, int fd, const char *name);
+
 char * get_ramdisk_path(const char *);
 char * get_uid_file_path(const char *, const char *);
 enum return_type verify_ramdisk_digest(const char *filename, const char *sha256_hash);