src/ipc/msgtool.c

   1 /*****************************************************************************
   2  Excerpt from "Linux Programmer's Guide - Chapter 6"
   3  (C)opyright 1994-1995, Scott Burkett
   4  *****************************************************************************
   5  MODULE: msgtool.c
   6  *****************************************************************************
   7  A command line tool for tinkering with SysV style Message Queues
   8  *****************************************************************************/
   9 /*
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License
  12  * as published by the Free Software Foundation; either version 2
  13  * of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  23  *
  24  * See the COPYING file for license information.
  25  */
  26
  27 #if HAVE_CONFIG_H
  28 #  include "config.h"
  29 #endif
  30
  31 #include "common.h"
  32
  33 #if HAVE_SYS_IPC_H
  34 #  include <sys/ipc.h>
  35 #endif
  36 #if HAVE_SYS_MSG_H
  37 #  include <sys/msg.h>
  38 #endif
  39
  40 #define MAX_SEND_SIZE 80
  41
  42 struct mymsgbuf {
  43         long mtype;
  44         char mtext[MAX_SEND_SIZE];
  45 };
  46
  47 void send_message(int qid, struct mymsgbuf *qbuf, long type, char *text);
  48 void read_message(int qid, struct mymsgbuf *qbuf, long type);
  49 void remove_queue(int qid);
  50 void change_queue_mode(int qid, char *mode);
  51 void usage(void);
  52
  53
  54 int main(int argc, char *argv[])
  55 {
  56         key_t key;
  57         int   msgqueue_id;
  58         struct mymsgbuf qbuf;
  59
  60         if(argc == 1)
  61                 usage();
  62
  63         /* Create unique key via call to ftok() */
  64         key = ftok(".", 'm');
  65
  66         /* Open the queue - create if necessary */
  67         if((msgqueue_id = msgget(key, IPC_CREAT|0660)) == -1) {
  68                 perror("msgget");
  69                 exit(1);
  70         }
  71
  72         switch(tolower(argv[1][0]))
  73         {
  74                 case 's': send_message(msgqueue_id, (struct mymsgbuf *)&qbuf,
  75                                        atol(argv[2]), argv[3]);
  76                           break;
  77                 case 'r': read_message(msgqueue_id, &qbuf, atol(argv[2]));
  78                           break;
  79                 case 'd': remove_queue(msgqueue_id);
  80                           break;
  81                 case 'm': change_queue_mode(msgqueue_id, argv[2]);
  82                           break;
  83
  84                  default: usage();
  85
  86         }
  87
  88         return(0);
  89 }
  90
  91 void send_message(int qid, struct mymsgbuf *qbuf, long type, char *text)
  92 {
  93         /* Send a message to the queue */
  94         printf("Sending a message ...\n");
  95         qbuf->mtype = type;
  96         strcpy(qbuf->mtext, text);
  97
  98         if((msgsnd(qid, (struct msgbuf *)qbuf,
  99                 strlen(qbuf->mtext)+1, 0)) ==-1)
 100         {
 101                 perror("msgsnd");
 102                 exit(1);
 103         }
 104 }
 105
 106 void read_message(int qid, struct mymsgbuf *qbuf, long type)
 107 {
 108         /* Read a message from the queue */
 109         printf("Reading a message ...\n");
 110         qbuf->mtype = type;
 111         msgrcv(qid, (struct msgbuf *)qbuf, MAX_SEND_SIZE, type, 0);
 112
 113         printf("Type: %ld Text: %s\n", qbuf->mtype, qbuf->mtext);
 114 }
 115
 116 void remove_queue(int qid)
 117 {
 118         /* Remove the queue */
 119         msgctl(qid, IPC_RMID, 0);
 120 }
 121
 122 void change_queue_mode(int qid, char *mode)
 123 {
 124         struct msqid_ds myqueue_ds;
 125
 126         /* Get current info */
 127         msgctl(qid, IPC_STAT, &myqueue_ds);
 128
 129         /* Convert and load the mode */
 130         sscanf(mode, "%ho", &myqueue_ds.msg_perm.mode);
 131
 132         /* Update the mode */
 133         msgctl(qid, IPC_SET, &myqueue_ds);
 134 }
 135
 136 void usage(void)
 137 {
 138         fprintf(stderr, "msgtool - A utility for tinkering with msg queues\n");
 139         fprintf(stderr, "\nUSAGE: msgtool (s)end <type> <messagetext>\n");
 140         fprintf(stderr, "               (r)ecv <type>\n");
 141         fprintf(stderr, "               (d)elete\n");
 142         fprintf(stderr, "               (m)ode <octal mode>\n");
 143         exit(1);
 144 }