monitor: print message when using 'help' with an unknown command

When typing 'help' followed by an unknown command, QEMU will
not print anything to the command line to let the user know
they typed a bad command. Let's fix this by printing a message
to the monitor when this happens. For example:

    (qemu) help xyz
    unknown command: 'xyz'

Reported-by: Stefan Zimmermann <stzi@linux.ibm.com>
Signed-off-by: Collin Walling <walling@linux.ibm.com>
Message-Id: <1532115624-27568-1-git-send-email-walling@linux.ibm.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

diff --git a/monitor.c b/monitor.c
index 3b90c9eb5fc16417ce49851771156061bd24b57f..c4677b502bb80eaaa6981a09c98783961fc53eed 100644 (file)
--- a/monitor.c
+++ b/monitor.c
@@ -952,6 +952,7 @@ static void help_cmd_dump(Monitor *mon, const mon_cmd_t *cmds,
                           char **args, int nb_args, int arg_index)
 {
     const mon_cmd_t *cmd;
+    size_t i;
 
     /* No valid arg need to compare with, dump all in *cmds */
     if (arg_index >= nb_args) {
@@ -973,9 +974,15 @@ static void help_cmd_dump(Monitor *mon, const mon_cmd_t *cmds,
             } else {
                 help_cmd_dump_one(mon, cmd, args, arg_index);
             }
-            break;
+            return;
         }
     }
+
+    /* Command not found */
+    monitor_printf(mon, "unknown command: '");
+    for (i = 0; i <= arg_index; i++) {
+        monitor_printf(mon, "%s%s", args[i], i == arg_index ? "'\n" : " ");
+    }
 }
 
 static void help_cmd(Monitor *mon, const char *name)