Mao Zhongyi <maozhon...@cmss.chinamobile.com> writes:
> run:
> (qemu) info migrate_parameters
> announce-initial: 50 ms
> ...
> announce-max: 550 ms
> multifd-compression: none
> xbzrle-cache-size: 4194304
> max-postcopy-bandwidth: 0
> tls-authz: '(null)'
>
> The last line seems a bit out of place, fix it.
Yes, indentation is off, and your patch fixes that. But there's also
the '(null)', which emanates a certain bug smell. Let's have a look at
the code:
> Signed-off-by: Mao Zhongyi <maozhon...@cmss.chinamobile.com>
> ---
> monitor/hmp-cmds.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
> index 58724031ea..f8be6bbb16 100644
> --- a/monitor/hmp-cmds.c
> +++ b/monitor/hmp-cmds.c
> @@ -459,7 +459,7 @@ void hmp_info_migrate_parameters(Monitor *mon, const
> QDict *qdict)
void hmp_info_migrate_parameters(Monitor *mon, const QDict *qdict)
{
MigrationParameters *params;
params = qmp_query_migrate_parameters(NULL);
if (params) {
[...]
> monitor_printf(mon, "%s: %" PRIu64 "\n",
>
> MigrationParameter_str(MIGRATION_PARAMETER_MAX_POSTCOPY_BANDWIDTH),
> params->max_postcopy_bandwidth);
> - monitor_printf(mon, " %s: '%s'\n",
> + monitor_printf(mon, "%s: '%s'\n",
> MigrationParameter_str(MIGRATION_PARAMETER_TLS_AUTHZ),
> params->has_tls_authz ? params->tls_authz : "");
> }
Here, params->tls_authz is null even though params->has_tls_authz is
true.
GNU Libc is nice enough not to crash when you attempt to print a null
pointer, but other libcs are not.
Where does the null pointer come from?
MigrationParameters *qmp_query_migrate_parameters(Error **errp)
{
MigrationParameters *params;
MigrationState *s = migrate_get_current();
/* TODO use QAPI_CLONE() instead of duplicating it inline */
params = g_malloc0(sizeof(*params));
[...]
---> params->has_tls_authz = true;
---> params->tls_authz = g_strdup(s->parameters.tls_authz);
[...]
return params;
}
Note we ignore s->parameters.has_tls_authz.
If @tls_authz is should be present in params exactly when it is present
in s->params, we should do this:
params->has_tls_authz = s->parameters.has_tls_authz;
params->tls_authz = g_strdup(s->parameters.tls_authz);
If @tls_authz is should be present exactly when it's not null, we should
do this:
params->has_tls_authz = !!s->parameters.tls_authz;
params->tls_authz = g_strdup(s->parameters.tls_authz);
If @tls_authz should always be present, we need to substitute the null
pointer by a suitable string, like this:
params->has_tls_authz = true;
params->tls_authz = s->parameters.tls_authz
? g_strdup(s->parameters.tls_authz) : "";
The /* TODO use QAPI_CLONE() instead of duplicating it inline */
suggests yet another possible fix.
David (cc'ed) should be able to tell us which fix is right.
@tls_creds and @tls_hostname look like they could have the same issue.
