From 68e24566b6ba442b2bdba2dfc111c5a0d333cc42 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Mon, 16 Jan 2012 17:06:41 -0500
Subject: vac: fix segfault on DMSYMLINK or DMDEVICE

Fix segfault when the first archived file is DMSYMLINK or DMDEVICE.
Reinitialize the buffer to zero before calling readlink.

R=rsc
CC=plan9port.codebot
http://codereview.appspot.com/5500097
---
 src/cmd/vac/vac.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

(limited to 'src/cmd')

diff --git a/src/cmd/vac/vac.c b/src/cmd/vac/vac.c
index 5f896310..03ada7b9 100644
--- a/src/cmd/vac/vac.c
+++ b/src/cmd/vac/vac.c
@@ -501,12 +501,17 @@ vac(VacFile *fp, VacFile *diffp, char *name, Dir *d)
 
 	if(vacfilesetdir(f, &vd) < 0)
 		warn("vacfilesetdir %s: %r", name);
-	
+
+	bsize = fs->bsize;
+	if(buf == nil)
+		buf = vtmallocz(bsize);
+
 #ifdef PLAN9PORT
 	if(d->mode&(DMSOCKET|DMNAMEDPIPE)){
 		/* don't write anything */
 	}
 	else if(d->mode&DMSYMLINK){
+		memset(buf, 0, sizeof buf);
 		n = readlink(name, buf, sizeof buf);
 		if(n > 0 && vacfilewrite(f, buf, n, 0) < 0){
 			warn("venti write %s: %r", name);
@@ -539,9 +544,6 @@ vac(VacFile *fp, VacFile *diffp, char *name, Dir *d)
 		}
 	}else{
 		off = 0;
-		bsize = fs->bsize;
-		if(buf == nil)
-			buf = vtmallocz(bsize);
 		if(fdiff){
 			/*
 			 * Copy fdiff's contents into f by moving the score.
-- 
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