commit 61ed2684539f7f31304e193d7c0e68d57ce6be88
author Max Reitz <mreitz@redhat.com> Sat Oct 26 15:44:43 2013 +0200
committer Kevin Wolf <kwolf@redhat.com> Mon Oct 28 17:35:52 2013 +0100
tree 611df1028c679cdfc23e4d40dd8acf918c05ae6e
parent d1f3a23bfac4fe38056ab5e07186939b7be8852b

block: Don't copy backing file name on error

bdrv_open_backing_file() tries to copy the backing file name using
pstrcpy directly after calling bdrv_open() to open the backing file
without checking whether that was actually successful. If it was not,
ps->backing_hd->file will probably be NULL and qemu will crash.

Fix this by moving pstrcpy after checking whether bdrv_open() succeeded.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Amos Kong <kongjianjun@gmail.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block.c

diff --git a/block.c b/block.c
index fd05a80..366999b 100644
--- a/block.c
+++ b/block.c
@@ -1004,8 +1004,6 @@
     ret = bdrv_open(bs->backing_hd,
                     *backing_filename ? backing_filename : NULL, options,
                     back_flags, back_drv, &local_err);
-    pstrcpy(bs->backing_file, sizeof(bs->backing_file),
-            bs->backing_hd->file->filename);
     if (ret < 0) {
         bdrv_unref(bs->backing_hd);
         bs->backing_hd = NULL;
@@ -1013,6 +1011,8 @@
         error_propagate(errp, local_err);
         return ret;
     }
+    pstrcpy(bs->backing_file, sizeof(bs->backing_file),
+            bs->backing_hd->file->filename);
     return 0;
 }