monitor: Rework early disk password inquiry (Jan Kiszka)

Reading the passwords for encrypted hard disks during early startup is
broken (I guess for quiet a while now):
 - No monitor terminal is ready for input at this point
 - Forcing all mux'ed terminals into monitor mode can confuse other
   users of that channels

To overcome these issues and to lay the ground for a clean decoupling of
monitor terminals, this patch changes the initial password inquiry as
follows:
 - Prevent autostart if there is some encrypted disk
 - Once the user tries to resume the VM, prompt for all missing
   passwords
 - Only resume if all passwords were accepted

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6707 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 13 insertions, 1 deletions

diff --git a/block.c b/block.c
index 5f3f780..78ab2d0 100644
--- a/block.c
+++ b/block.c
@@ -336,6 +336,7 @@ int bdrv_open2(BlockDriverState *bs, const char *filename, int flags,
     bs->read_only = 0;
     bs->is_temporary = 0;
     bs->encrypted = 0;
+    bs->valid_key = 0;
 
     if (flags & BDRV_O_SNAPSHOT) {
         BlockDriverState *bs1;
@@ -966,6 +967,15 @@ int bdrv_is_encrypted(BlockDriverState *bs)
     return bs->encrypted;
 }
 
+int bdrv_key_required(BlockDriverState *bs)
+{
+    BlockDriverState *backing_hd = bs->backing_hd;
+
+    if (backing_hd && backing_hd->encrypted && !backing_hd->valid_key)
+        return 1;
+    return (bs->encrypted && !bs->valid_key);
+}
+
 int bdrv_set_key(BlockDriverState *bs, const char *key)
 {
     int ret;
@@ -978,7 +988,9 @@ int bdrv_set_key(BlockDriverState *bs, const char *key)
     }
     if (!bs->encrypted || !bs->drv || !bs->drv->bdrv_set_key)
         return -1;
-    return bs->drv->bdrv_set_key(bs, key);
+    ret = bs->drv->bdrv_set_key(bs, key);
+    bs->valid_key = (ret == 0);
+    return ret;
 }
 
 void bdrv_get_format(BlockDriverState *bs, char *buf, int buf_size)