NeilBrown: super0: fix crash on assemble if homehost is not set.

[Martin F. Krafft]

Module: mdadm
Branch: upstream
Commit: 40d28f0d1bf28bc706b734932f46a9190b9fec5b
URL:    http://git.debian.org/?p=pkg-mdadm/mdadm.git;a=commit;h=40d28f0d1bf28bc706b734932f46a9190b9fec5b

Author: NeilBrown <neilb at suse.de>
Date:   Fri Sep 25 17:56:22 2009 +1000

super0: fix crash on assemble if homehost is not set.

If homehost is not set - typically during early boot,
and assemble of v0.90 metadata arrays will crash.

Reported-by: Paweł Sikora <pluto at agmk.net>
Signed-off-by: NeilBrown <neilb at suse.de>

---

 super0.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/super0.c b/super0.c
index 2b4942f..07f4792 100644
--- a/super0.c
+++ b/super0.c
@@ -305,9 +305,13 @@ static int match_home0(struct supertype *st, char *homehost)
 {
 	mdp_super_t *sb = st->sb;
 	char buf[20];
-	char *hash = sha1_buffer(homehost,
-				 strlen(homehost),
-				 buf);
+	char *hash;
+
+	if (!homehost)
+		return 0;
+	hash = sha1_buffer(homehost,
+			   strlen(homehost),
+			   buf);
 
 	return (memcmp(&sb->set_uuid2, hash, 8)==0);
 }