From: Tobias Stoeckmann <tobias@stoeckmann.org>
Date: Tue, 30 Aug 2016 19:00:38 +0000 (+0200)
Subject: lib/loopdev: Set errno in is_loopdev on error
X-Git-Tag: v2.28.2~12
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ce7d7d2ff9a3d3d2f07dc578c2bc15034e7f44ea;p=thirdparty%2Futil-linux.git

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 26c183e8d6..7a69cd9c7e 100644
--- 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;
 }
 
 /*