Currently, qemu-io only uses string-valued blockdev options (as all are
converted directly from QemuOpts) -- with one exception: -U adds the
force-share option as a boolean.  This in itself is already a bit
questionable, but a real issue is that it also assumes the value already
existing in the options QDict would be a boolean, which is wrong.

That has the following effect:

$ ./qemu-io -r -U --image-opts \
    driver=file,filename=/dev/null,force-share=off
[1]    15200 segmentation fault (core dumped)  ./qemu-io -r -U
--image-opts driver=file,filename=/dev/null,force-share=off

Since @opts is converted from QemuOpts, the value must be a string, and
we have to compare it as such.  Consequently, it makes sense to also set
it as a string instead of a boolean.

Cc: qemu-stable@nongnu.org
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 qemu-io.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/qemu-io.c b/qemu-io.c
index e692c555e0..0755a30447 100644
--- a/qemu-io.c
+++ b/qemu-io.c
@@ -95,12 +95,12 @@ static int openfile(char *name, int flags, bool writethrough, bool force_share,
             opts = qdict_new();
         }
         if (qdict_haskey(opts, BDRV_OPT_FORCE_SHARE)
-            && !qdict_get_bool(opts, BDRV_OPT_FORCE_SHARE)) {
+            && strcmp(qdict_get_str(opts, BDRV_OPT_FORCE_SHARE), "on")) {
             error_report("-U conflicts with image options");
             QDECREF(opts);
             return 1;
         }
-        qdict_put_bool(opts, BDRV_OPT_FORCE_SHARE, true);
+        qdict_put_str(opts, BDRV_OPT_FORCE_SHARE, "on");
     }
     qemuio_blk = blk_new_open(name, NULL, opts, flags, &local_err);
     if (!qemuio_blk) {
-- 
2.14.3

On 05/02/2018 03:20 PM, Max Reitz wrote:
> Currently, qemu-io only uses string-valued blockdev options (as all are
> converted directly from QemuOpts) -- with one exception: -U adds the
> force-share option as a boolean.  This in itself is already a bit
> questionable, but a real issue is that it also assumes the value already
> existing in the options QDict would be a boolean, which is wrong.
> 
> That has the following effect:
> 
> $ ./qemu-io -r -U --image-opts \
>      driver=file,filename=/dev/null,force-share=off
> [1]    15200 segmentation fault (core dumped)  ./qemu-io -r -U
> --image-opts driver=file,filename=/dev/null,force-share=off
> 
> Since @opts is converted from QemuOpts, the value must be a string, and
> we have to compare it as such.  Consequently, it makes sense to also set
> it as a string instead of a boolean.
> 
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>   qemu-io.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 

The curse of poor typing in QemuOpts keeps on giving ;)
Adding Markus, so he's aware of yet another wart that his command-line 
cleanups may need to visit.

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org