dabba/ipc.c

   1 /**
   2  * \file ipc.c
   3  * \author written by Emmanuel Roullit emmanuel.roullit@gmail.com (c) 2012
   4  * \date 2012
   5  */
   6
   7 /* __LICENSE_HEADER_BEGIN__ */
   8
   9 /*
  10  * Copyright (C) 2012   Emmanuel Roullit <emmanuel.roullit@gmail.com>
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or (at
  15  * your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  19  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
  20  * for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License along
  23  * with this program; if not, write to the Free Software Foundation, Inc.,
  24  * 51 Franklin St, Fifth Floor, Boston, MA 02110, USA
  25  *
  26  */
  27
  28 /* __LICENSE_HEADER_END__ */
  29
  30 #include <stdio.h>
  31 #include <string.h>
  32 #include <unistd.h>
  33 #include <assert.h>
  34 #include <errno.h>
  35 #include <dabba/ipc.h>
  36
  37 /**
  38  * \brief Communicate via IPC to the dabba daemon
  39  * \param[in,out]       msg             IPC message
  40  * \return 0 on success, else on failure.
  41  *
  42  * This function coordinates the communication between dabba and the dabba
  43  * daemon. It first sends a command request packed in an IPC message and
  44  * awaits for a response from the dabba daemon which contains the request error
  45  * code and the requested data.
  46  */
  47
  48 int dabba_ipc_msg(struct dabba_ipc_msg *msg)
  49 {
  50         int qid;
  51         ssize_t rcv;
  52         int snd;
  53
  54         assert(msg);
  55
  56         qid = dabba_get_ipc_queue_id(0660);
  57
  58         if (qid < 0) {
  59                 perror("Cannot get IPC id");
  60                 return errno;
  61         }
  62
  63         snd = msgsnd(qid, msg, sizeof(msg->msg_body), 0);
  64
  65         if (snd < 0) {
  66                 perror("Error while sending IPC msg");
  67                 return errno;
  68         }
  69
  70         usleep(100);
  71
  72         rcv = msgrcv(qid, msg, sizeof(msg->msg_body), 0, 0);
  73
  74         if (rcv <= 0) {
  75                 perror("Error while receiving IPC msg");
  76                 return errno;
  77         }
  78
  79         if (msg->msg_body.error != 0) {
  80                 printf("The daemon reported: %s\n",
  81                        strerror(msg->msg_body.error));
  82                 return msg->msg_body.error;
  83         }
  84
  85         return 0;
  86 }