ceph.in: better error message when daemon command returns nothing

Fixes: #5683
signed-off-by: Dan Mick <dan.mick@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/src/ceph.in b/src/ceph.in
index 0f7179b8aed..6ba92c99b18 100755
--- a/src/ceph.in
+++ b/src/ceph.in
@@ -290,6 +290,8 @@ def admin_socket(asok_path, cmd):
         sock.sendall(' '.join(cmd) + '\0')
 
         len_str = sock.recv(4)
+        if len(len_str) < 4:
+            raise RuntimeError("no data returned from admin socket")
         l, = struct.unpack(">I", len_str)
         ret = ''