From: Jes Sorensen <Jes.Sorensen@redhat.com>
Date: Tue, 1 Nov 2011 19:30:12 +0000 (+0100)
Subject: make_parts(): Fix case of comparing against uninitialized variables
X-Git-Tag: mdadm-3.2.3~77
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=96ae5973dda6f6f6487c74b5f3944720a5b9d21f;p=thirdparty%2Fmdadm.git

make_parts(): Fix case of comparing against uninitialized variables

Silencing gcc's warning of uninitialized variables was hiding a bug
where if we have /dev/md64 as a symlink, and /dev/md64p1 was a real
device node.

In this case major_num and minor_num would not get populated, but we
end up comparing against them because the stat for md64p1 succeeds.

Instead of using the int foo = foo trick, change the code to set
set the variables to invalid values so comparisons will fail.

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/mdopen.c b/mdopen.c
index 555ab84f..eac1c1fc 100644
--- a/mdopen.c
+++ b/mdopen.c
@@ -38,9 +38,9 @@ void make_parts(char *dev, int cnt)
 	 * else that of dev
 	 */
 	struct stat stb;
-	int major_num = major_num; /* quiet gcc -Os unitialized warning */
-	int minor_num = minor_num; /* quiet gcc -Os unitialized warning */
-	int odig = odig; /* quiet gcc -Os unitialized warning */
+	int major_num;
+	int minor_num;
+	int odig;
 	int i;
 	int nlen = strlen(dev) + 20;
 	char *name;
@@ -53,23 +53,26 @@ void make_parts(char *dev, int cnt)
 	if (lstat(dev, &stb)!= 0)
 		return;
 
-	if (S_ISLNK(stb.st_mode)) {
+	if (S_ISBLK(stb.st_mode)) {
+		major_num = major(stb.st_rdev);
+		minor_num = minor(stb.st_rdev);
+		odig = -1;
+	} else if (S_ISLNK(stb.st_mode)) {
 		int len = readlink(dev, orig, sizeof(orig));
 		if (len < 0 || len > 1000)
 			return;
 		orig[len] = 0;
 		odig = isdigit(orig[len-1]);
-	} else if (S_ISBLK(stb.st_mode)) {
-		major_num = major(stb.st_rdev);
-		minor_num = minor(stb.st_rdev);
+		major_num = -1;
+		minor_num = -1;
 	} else
-		   return;
+		return;
 	name = malloc(nlen);
 	for (i=1; i <= cnt ; i++) {
 		struct stat stb2;
 		snprintf(name, nlen, "%s%s%d", dev, dig?"p":"", i);
 		if (stat(name, &stb2)==0) {
-			if (!S_ISBLK(stb2.st_mode))
+			if (!S_ISBLK(stb2.st_mode) || !S_ISBLK(stb.st_mode))
 				continue;
 			if (stb2.st_rdev == makedev(major_num, minor_num+i))
 				continue;