Re: [PATCH v3 1/6] migration/tls: save hostname into MigrationState

[Zheng Chuan]

On 2020/9/14 17:00, Daniel P. Berrangé wrote:
> On Sun, Sep 13, 2020 at 10:47:31AM +0800, Chuan Zheng wrote:
>> hostname is need in multifd-tls, save hostname into MigrationState.
>>
>> Signed-off-by: Chuan Zheng <zhengchuan@huawei.com>
>> Signed-off-by: Yan Jin <jinyan12@huawei.com>
>> ---
>>  migration/channel.c   | 6 ++++++
>>  migration/migration.c | 1 +
>>  migration/migration.h | 5 +++++
>>  3 files changed, 12 insertions(+)
>>
>> diff --git a/migration/channel.c b/migration/channel.c
>> index 20e4c8e..0e4104a 100644
>> --- a/migration/channel.c
>> +++ b/migration/channel.c
>> @@ -66,6 +66,11 @@ void migration_channel_connect(MigrationState *s,
>>      trace_migration_set_outgoing_channel(
>>          ioc, object_get_typename(OBJECT(ioc)), hostname, error);
>>  
>> +    /* Save hostname into MigrationState for handshake */
>> +    if (hostname) {
>> +        s->hostname = g_strdup(hostname);
>> +    }
>> +
>>      if (!error) {
>>          if (s->parameters.tls_creds &&
>>              *s->parameters.tls_creds &&
>> @@ -90,5 +95,6 @@ void migration_channel_connect(MigrationState *s,
>>          }
>>      }
>>      migrate_fd_connect(s, error);
>> +    g_free(s->hostname);
>>      error_free(error);
>>  }
> 
> IIUC, this means hostname is free'd once the initial connection is
> established. Don't we have to wait until all the multifd connections
> exist too ?
> 
> IOW, should we be doing this somewhere in a cleanup path. Perhaps
> migrate_fd_cancel() is the rigt place ?
> 

Well, Maybe another alternate way is define series functions to save/destroy 
tls_hostname in 'tls.c'
other than add hostname into MigrationState.
such as:

+static char *migration_tls_hostname = NULL;
+
+void migration_destroy_tls_hostname(void)
+{
+    if (migration_tls_hostname) {
+        g_free(migration_tls_hostname);
+        migration_tls_hostname = NULL;
+    }
+}
+
+static void migration_save_tls_hostname(const char *hostname)
+{
+     migration_destroy_tls_hostname();
+     migration_tls_hostname = g_strdup(hostname);
+}
+
+char *migration_get_tls_hostname(void)
+{
+     return migration_tls_hostname;
+}

How do you think, is that better?

>> diff --git a/migration/migration.c b/migration/migration.c
>> index 58a5452..e20b778 100644
>> --- a/migration/migration.c
>> +++ b/migration/migration.c
>> @@ -1883,6 +1883,7 @@ void migrate_init(MigrationState *s)
>>      s->migration_thread_running = false;
>>      error_free(s->error);
>>      s->error = NULL;
>> +    s->hostname = NULL;
>>  
>>      migrate_set_state(&s->state, MIGRATION_STATUS_NONE, 
>> MIGRATION_STATUS_SETUP);
>>  
>> diff --git a/migration/migration.h b/migration/migration.h
>> index bdc7450..bc96322 100644
>> --- a/migration/migration.h
>> +++ b/migration/migration.h
>> @@ -259,6 +259,11 @@ struct MigrationState
>>       * (which is in 4M chunk).
>>       */
>>      uint8_t clear_bitmap_shift;
>> +
>> +    /*
>> +     * This save hostname when out-going migration starts
>> +     */
>> +    char *hostname;
>>  };
>>  
>>  void migrate_set_state(int *state, int old_state, int new_state);
>> -- 
>> 1.8.3.1
>>
> 
> Regards,
> Daniel
>