/************  * MsgQue.c * ************/#include <stdio.h>#include <stdlib.h>#include <ctype.h>#include <sys/types.h>#include <sys/ipc.h>#include <sys/msg.h>#define MAX_SEND_SIZE 80struct mymsgbuf {long mtype;char mtext[MAX_SEND_SIZE];};void send_message(int qid, struct mymsgbuf *qbuf, long type, char *text);void read_message(int qid, struct mymsgbuf *qbuf, long type);void remove_queue(int qid);void change_queue_mode(int qid, char *mode);void usage(void);int main(int argc, char *argv[]){key_t key;int msgqueue_id;struct mymsgbuf qbuf;if(argc == 1)usage();/* Create unique key via call to ftok() *//* key = ftok(".", 'w'); */ key = 123456;printf("key=%d\n",key);key=IPC_PRIVATE;/* Open the queue - create if necessary */if((tolower(argv[1][0]))!='s'){if((msgqueue_id = msgget(key, IPC_CREAT|0666)) == -1) {perror("msgget");exit(1);}printf("msgqueue_id=%d\n",msgqueue_id);}switch(tolower(argv[1][0])){case 's': send_message(atoi(argv[4]), (struct mymsgbuf *)&qbuf,atol(argv[2]), argv[3]); break;case 'r': read_message(msgqueue_id, &qbuf, atol(argv[2])); break;case 'd': remove_queue(atoi(argv[2])); remove_queue(msgqueue_id);break; case 'm': change_queue_mode(msgqueue_id, argv[2]); break;default: usage();}return(0);}void send_message(int qid, struct mymsgbuf *qbuf, long type, char *text){printf("msgqueue_id=%d\n",qid);/* Send a message to the queue */printf("Sending a message ...\n");qbuf->mtype = type;strcpy(qbuf->mtext, text);printf(" Type: %ld Text: %s\n", qbuf->mtype, qbuf->mtext);if((msgsnd(qid, (struct msgbuf *)qbuf,strlen(qbuf->mtext)+1, 0)) ==-1){perror("msgsnd");exit(1);}}void read_message(int qid, struct mymsgbuf *qbuf, long type){/* Read a message from the queue */printf("Reading a message ...\n");qbuf->mtype = type;msgrcv(qid, (struct msgbuf *)qbuf, MAX_SEND_SIZE, type, 0);printf(" Type: %ld Text: %s\n", qbuf->mtype, qbuf->mtext);}void remove_queue(int qid){/* Remove the queue */msgctl(qid, IPC_RMID, 0);}void change_queue_mode(int qid, char *mode){struct msqid_ds myqueue_ds;/* Get current info */msgctl(qid, IPC_STAT, &myqueue_ds);/* Convert and load the mode */sscanf(mode, "%ho", &myqueue_ds.msg_perm.mode);/* Update the mode */msgctl(qid, IPC_SET, &myqueue_ds);}void usage(void){fprintf(stderr, "msgtool - A utility for tinkering with msg queues\n");fprintf(stderr, "\nUSAGE: msgtool (s)end <type> <messagetext> <msgid>\n");fprintf(stderr, " (r)ecv <type>\n");fprintf(stderr, " (d)elete\n");fprintf(stderr, " (m)ode <octal mode>\n");fprintf(stderr, "note: type must be number!\n");exit(1);}