From: Karel Zak <kzak@redhat.com>
Date: Wed, 17 Oct 2012 09:43:39 +0000 (+0200)
Subject: lib/loopdev: check for /sys
X-Git-Tag: v2.22.2~42
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=939636dd664cc608232c272de77be96e6f089235;p=thirdparty%2Futil-linux.git

lib/loopdev: check for /sys

The current loopdev code prefers /sys to get information about
loop devices. The old methods like scan /dev are fallback solution
only. Unfortunately, the code does not check if /sys is mounted.

Addresses: http://blog.flameeyes.eu/2012/10/sophistication-can-be-bad
Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/lib/loopdev.c b/lib/loopdev.c
index 0e6033a255..f62af83c28 100644
--- a/lib/loopdev.c
+++ b/lib/loopdev.c
@@ -167,6 +167,12 @@ int loopcxt_init(struct loopdev_cxt *lc, int flags)
 	if (rc)
 		return rc;
 
+	if (stat(_PATH_SYS_BLOCK, &st) || !S_ISDIR(st.st_mode)) {
+		lc->flags |= LOOPDEV_FL_NOSYSFS;
+		lc->flags &= ~LOOPDEV_FL_NOIOCTL;
+		DBG(lc, loopdev_debug("init: disable /sys usage"));
+	}
+
 	if (!(lc->flags & LOOPDEV_FL_NOSYSFS) &&
 	    get_linux_version() >= KERNEL_VERSION(2,6,37)) {
 		/*