qemu-io-cmds: assert that we don't have .perm requested in no-blk case

Coverity thinks blk may be NULL. It's a false-positive, as described in
a new comment.

Fixes: Coverity CID 1453194
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210519090532.3753-1-vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 12 insertions, 2 deletions

diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
index 998b67186d..e8d862a426 100644
--- a/qemu-io-cmds.c
+++ b/qemu-io-cmds.c
@@ -92,9 +92,19 @@ static int command(BlockBackend *blk, const cmdinfo_t *ct, int argc,
         return -EINVAL;
     }
 
-    /* Request additional permissions if necessary for this command. The caller
+    /*
+     * Request additional permissions if necessary for this command. The caller
      * is responsible for restoring the original permissions afterwards if this
-     * is what it wants. */
+     * is what it wants.
+     *
+     * Coverity thinks that blk may be NULL in the following if condition. It's
+     * not so: in init_check_command() we fail if blk is NULL for command with
+     * both CMD_FLAG_GLOBAL and CMD_NOFILE_OK flags unset. And in
+     * qemuio_add_command() we assert that command with non-zero .perm field
+     * doesn't set this flags. So, the following assertion is to silence
+     * Coverity:
+     */
+    assert(blk || !ct->perm);
     if (ct->perm && blk_is_available(blk)) {
         uint64_t orig_perm, orig_shared_perm;
         blk_get_perm(blk, &orig_perm, &orig_shared_perm);