Fix a bug where mount could check the wrong device.  st_rdev is the correct
device ID iff the named file is a character or block special device.  Otherwise
it is meaningless junk, in which case st_dev should be used.  This was done
incorrectly, which could cause mount to display bogus mount info.
 -Erik
diff --git a/libbb/find_root_device.c b/libbb/find_root_device.c
index c595321..836ce44 100644
--- a/libbb/find_root_device.c
+++ b/libbb/find_root_device.c
@@ -38,8 +38,11 @@
 	if (stat("/", &rootStat) != 0) 
 		bb_perror_msg("could not stat '/'");
 	else {
-		if ((dev = rootStat.st_rdev)==0) 
-			dev=rootStat.st_dev;
+		/* This check is here in case they pass in /dev name */
+		if ((rootStat.st_mode & S_IFMT) == S_IFBLK)
+			dev = rootStat.st_rdev;
+		else
+			dev = rootStat.st_dev;
 
 		dir = opendir("/dev");
 		if (!dir)