json: Fix to reject duplicate object member names
The JSON parser happily accepts duplicate object member names. The
last value wins. Reproducer #1:
$ qemu-system-x86_64 -qmp stdio
{"QMP": {"version": {"qemu": {"micro": 93, "minor": 0, "major": 3},
"package": "v3.1.0-rc3-7-g87a45d86ed"}, "capabilities": []}}
{'execute':'qmp_capabilities'}
{"return": {}}
{'execute':'blockdev-add','arguments':{'driver':'null-co',
'node-name':'foo','node-name':'bar'}}
{"return": {}}
{'execute':'query-named-block-nodes'}
{"return": [{ [...] "node-name": "bar" [...] }]}
Reproducer #2 is iotest 229.
Fix the parser to reject duplicates, and fix iotest 229 not to use
them.
Reported-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20181206121743.20762-1-armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
[Trailing whitespace tidied up]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
00382fa851