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author | Markus Armbruster <armbru@redhat.com> | 2013-08-02 09:34:00 +0200 |
---|---|---|
committer | Anthony Liguori <aliguori@us.ibm.com> | 2013-08-12 09:15:37 -0500 |
commit | cb77d1925ac4d673e19be58aa39fc53c5d2fed10 (patch) | |
tree | 106654b1271da3ba4f59bb3a8e39546c12607314 | |
parent | 8571fa57cd0426f40629ab77444704745631f168 (diff) | |
download | hqemu-cb77d1925ac4d673e19be58aa39fc53c5d2fed10.zip hqemu-cb77d1925ac4d673e19be58aa39fc53c5d2fed10.tar.gz |
qemu-option: Guard against qemu_opts_set_defaults() misuse
Commit 6d4cd40 fixed qemu_opts_set_defaults() for an existing corner
case, but broke it for another one that can't be reached in current
code.
Quote from its commit message:
I believe [opts_parse()] attempts to do the following:
If options don't yet exist, create new options
Else, if defaults, modify the existing options
Else, if list->merge_lists, modify the existing options
Else, fail
The only caller that passes true for defaults is
qemu_opts_set_defaults().
The commit message then claims:
A straightforward call of qemu_opts_create() does exactly that.
Wrong. When !list->merge_lists, and the option string doesn't contain
id=, and options without ID exist, then we don't actually modify the
existing options, we create new ones.
Not reachable, because we never pass lists with !list->merge_lists to
qemu_opts_set_defaults().
Guard against possible (if unlikely) future misuse with assert().
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1375428840-5275-1-git-send-email-armbru@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
-rw-r--r-- | util/qemu-option.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/util/qemu-option.c b/util/qemu-option.c index 7a1552a..4ebdc4c 100644 --- a/util/qemu-option.c +++ b/util/qemu-option.c @@ -928,6 +928,15 @@ static QemuOpts *opts_parse(QemuOptsList *list, const char *params, get_opt_value(value, sizeof(value), p+4); id = value; } + + /* + * This code doesn't work for defaults && !list->merge_lists: when + * params has no id=, and list has an element with !opts->id, it + * appends a new element instead of returning the existing opts. + * However, we got no use for this case. Guard against possible + * (if unlikely) future misuse: + */ + assert(!defaults || list->merge_lists); opts = qemu_opts_create(list, id, !defaults, &local_err); if (opts == NULL) { if (error_is_set(&local_err)) { |