From bdd2925eaebdbba0400da3ebef201f402c3cee90 Mon Sep 17 00:00:00 2001
From: Max Reitz <mreitz@redhat.com>
Date: Mon, 18 Jun 2018 14:59:41 +0200
Subject: [PATCH 068/268] qemu-img: Recognize no creation support in -o help

RH-Author: Max Reitz <mreitz@redhat.com>
Message-id: <20180618145943.4489-6-mreitz@redhat.com>
Patchwork-id: 80759
O-Subject: [RHV-7.6 qemu-kvm-rhev PATCH 5/7] qemu-img: Recognize no creation support in -o help
Bugzilla: 1537956
RH-Acked-by: John Snow <jsnow@redhat.com>
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

The only users of print_block_option_help() are qemu-img create and
qemu-img convert for the output image, so this function is always used
for image creation (it used to be used for amendment also, but that is
no longer the case).

So if image creation is not supported by either the format or the
protocol, there is no need to print any option description, because the
user cannot create an image like this anyway.

This also fixes an assertion failure:

    $ qemu-img create -f bochs -o help
    Supported options:
    qemu-img: util/qemu-option.c:219:
    qemu_opts_print_help: Assertion `list' failed.
    [1]    24831 abort (core dumped)  qemu-img create -f bochs -o help

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20180509210023.20283-6-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
(cherry picked from commit d402b6a21a825a5c07aac9251990860723d49f5d)
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 qemu-img.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/qemu-img.c b/qemu-img.c
index d4cbb63..4bcf157 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -250,6 +250,11 @@ static int print_block_option_help(const char *filename, const char *fmt)
         return 1;
     }
 
+    if (!drv->create_opts) {
+        error_report("Format driver '%s' does not support image creation", fmt);
+        return 1;
+    }
+
     create_opts = qemu_opts_append(create_opts, drv->create_opts);
     if (filename) {
         proto_drv = bdrv_find_protocol(filename, true, &local_err);
@@ -258,6 +263,11 @@ static int print_block_option_help(const char *filename, const char *fmt)
             qemu_opts_free(create_opts);
             return 1;
         }
+        if (!proto_drv->create_opts) {
+            error_report("Protocal driver '%s' does not support image creation",
+                         proto_drv->format_name);
+            return 1;
+        }
         create_opts = qemu_opts_append(create_opts, proto_drv->create_opts);
     }
 
-- 
1.8.3.1