ltt-sessiond/ust-comm.c

   1 /*
   2  * Copyright (C)  2011 - David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; only version 2
   7  * of the License.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17  */
  18
  19 #include <config.h>
  20 #include <stdlib.h>
  21 #include <lttngerr.h>
  22 #include <ust/lttng-ust-comm.h>
  23 #include "ust-comm.h"
  24
  25 /*
  26  * Send msg containing a command to an UST application via sock and wait for
  27  * the reply. Caller must free() the reply structure sent back.
  28  *
  29  * Return the replied structure or NULL.
  30  */
  31 struct lttcomm_ust_reply *ustcomm_send_command(int sock,
  32                 struct lttcomm_ust_msg *msg)
  33 {
  34         ssize_t len;
  35         struct lttcomm_ust_reply *reply;
  36
  37         /* Extra safety */
  38         if (msg == NULL || sock < 0) {
  39                 goto error;
  40         }
  41
  42         DBG2("Sending UST command %d to sock %d", msg->cmd, sock);
  43
  44         /* Send UST msg */
  45         len = ustcomm_send_unix_sock(sock, msg, sizeof(*msg));
  46         if (len < 0) {
  47                 goto error;
  48         }
  49
  50         reply = malloc(sizeof(struct lttcomm_ust_reply));
  51         if (reply == NULL) {
  52                 perror("malloc ust reply");
  53                 goto error;
  54         }
  55
  56         DBG2("Receiving UST reply on sock %d", sock);
  57
  58         /* Get UST reply */
  59         len = ustcomm_recv_unix_sock(sock, reply, sizeof(*reply));
  60         if (len < 0 || len < sizeof(*reply)) {
  61                 goto error;
  62         }
  63
  64         return reply;
  65
  66 error:
  67         return NULL;
  68 }