From: Kay Sievers <kay.sievers@vrfy.org>
Date: Sat, 3 Feb 2007 00:12:34 +0000 (+0100)
Subject: volume_id: really fix endianess bug in linux_raid detection
X-Git-Tag: 174~2072
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=ac77e95948edc199cdd690de38f08e4d1e615840

volume_id: really fix endianess bug in linux_raid detection

Seems we find the md signature in cpu-order on the disk. Let's
look for both endian encodings ...

Thanks to Michael Prokop for his help finding the bug.
---

diff --git a/extras/volume_id/lib/Makefile b/extras/volume_id/lib/Makefile
index a3e947cea..5ad9f2e56 100644
--- a/extras/volume_id/lib/Makefile
+++ b/extras/volume_id/lib/Makefile
@@ -13,7 +13,7 @@ INSTALL_DATA  = ${INSTALL} -m 644
 INSTALL_LIB = ${INSTALL} -m 755
 
 SHLIB_CUR = 0
-SHLIB_REV = 74
+SHLIB_REV = 75
 SHLIB_AGE = 0
 SHLIB = libvolume_id.so.$(SHLIB_CUR).$(SHLIB_REV).$(SHLIB_AGE)
 
diff --git a/extras/volume_id/lib/linux_raid.c b/extras/volume_id/lib/linux_raid.c
index b8a819f67..a9c5d61ad 100644
--- a/extras/volume_id/lib/linux_raid.c
+++ b/extras/volume_id/lib/linux_raid.c
@@ -46,7 +46,8 @@ static struct mdp_super_block {
 } PACKED *mdp;
 
 #define MD_RESERVED_BYTES		0x10000
-#define MD_MAGIC			"\xa9\x2b\x4e\xfc"
+#define MD_MAGIC			"\xfc\x4e\x2b\xa9"
+#define MD_MAGIC_SWAP			"\xa9\x2b\x4e\xfc"
 
 int volume_id_probe_linux_raid(struct volume_id *id, uint64_t off, uint64_t size)
 {
@@ -65,7 +66,8 @@ int volume_id_probe_linux_raid(struct volume_id *id, uint64_t off, uint64_t size
 		return -1;
 	mdp = (struct mdp_super_block *) buf;
 
-	if (memcmp(mdp->md_magic, MD_MAGIC, 4) != 0)
+	if ((memcmp(mdp->md_magic, MD_MAGIC, 4) != 0) &&
+	    (memcmp(mdp->md_magic, MD_MAGIC_SWAP, 4) != 0))
 		return -1;
 
 	memcpy(uuid, &mdp->set_uuid0, 4);