lib/loopdev: Set errno in is_loopdev on error

The function is_loopdev does not set errno if the supplied string does
not reference a valid loop device. Fix this to avoid an error message
like this one:

  losetup: /: failed to use device: Success

I prefer this one:

  losetup: /: failed to use device: No such device

Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>

diff --git a/lib/loopdev.c b/lib/loopdev.c
index 26c183e8d6a5c03505cf6268e32cb7c315f599df..7a69cd9c7e0ec880699b19ad08944c4c934788f9 100644 (file)
--- a/lib/loopdev.c
+++ b/lib/loopdev.c
@@ -634,12 +634,13 @@ int is_loopdev(const char *device)
 {
        struct stat st;
 
-       if (!device)
-               return 0;
-
-       return (stat(device, &st) == 0 &&
+       if (device && stat(device, &st) == 0 &&
                S_ISBLK(st.st_mode) &&
-               major(st.st_rdev) == LOOPDEV_MAJOR);
+               major(st.st_rdev) == LOOPDEV_MAJOR)
+               return 1;
+
+       errno = ENODEV;
+       return 0;
 }
 
 /*