153 lines
3.6 KiB
C
153 lines
3.6 KiB
C
/*************************************************************************
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> File Name : ipc_share_mem_client.c
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> Author : TL Song
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> EMail : songtianlun@frytea.com
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> Created Time : Mon 28 Dec 2020 03:54:50 PM CST
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************************************************************************/
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#include<stdio.h>
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#include<stdlib.h>
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#include<sys/shm.h> // shared memory
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#include<sys/sem.h> // semaphore
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#include<sys/msg.h> // message queue
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#include<string.h> // memcpy
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// 消息队列结构
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struct msg_form {
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long mtype;
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char mtext;
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};
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// 联合体，用于semctl初始化
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union semun
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{
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int val; /*for SETVAL*/
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struct semid_ds *buf;
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unsigned short *array;
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};
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// P操作:
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// 若信号量值为1，获取资源并将信号量值-1
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// 若信号量值为0，进程挂起等待
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int sem_p(int sem_id)
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{
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struct sembuf sbuf;
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sbuf.sem_num = 0; /*序号*/
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sbuf.sem_op = -1; /*P操作*/
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sbuf.sem_flg = SEM_UNDO;
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if(semop(sem_id, &sbuf, 1) == -1)
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{
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perror("P operation Error");
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return -1;
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}
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return 0;
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}
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// V操作：
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// 释放资源并将信号量值+1
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// 如果有进程正在挂起等待，则唤醒它们
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int sem_v(int sem_id)
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{
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struct sembuf sbuf;
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sbuf.sem_num = 0; /*序号*/
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sbuf.sem_op = 1; /*V操作*/
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sbuf.sem_flg = SEM_UNDO;
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if(semop(sem_id, &sbuf, 1) == -1)
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{
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perror("V operation Error");
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return -1;
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}
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return 0;
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}
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int main()
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{
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key_t key;
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int shmid, semid, msqid;
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char *shm;
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struct msg_form msg;
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int flag = 1; /*while循环条件*/
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// 获取key值
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if((key = ftok(".", 'z')) < 0)
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{
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perror("ftok error");
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exit(1);
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}
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// 获取共享内存
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if((shmid = shmget(key, 1024, 0)) == -1)
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{
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perror("shmget error");
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exit(1);
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}
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// 连接共享内存
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shm = (char*)shmat(shmid, 0, 0);
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if((int)shm == -1)
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{
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perror("Attach Shared Memory Error");
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exit(1);
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}
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// 创建消息队列
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if ((msqid = msgget(key, 0)) == -1)
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{
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perror("msgget error");
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exit(1);
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}
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// 获取信号量
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if((semid = semget(key, 0, 0)) == -1)
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{
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perror("semget error");
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exit(1);
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}
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// 写数据
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printf("***************************************\n");
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printf("* IPC *\n");
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printf("* Input r to send data to server. *\n");
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printf("* Input q to quit. *\n");
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printf("***************************************\n");
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system("/proc/$$/ns");
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while(flag)
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{
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char c = 'r';
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printf("Please input command: ");
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//scanf("%c", &c);
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switch(c)
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{
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case 'r':
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printf("Data to send: ");
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sem_p(semid); /*访问资源*/
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//scanf("%s", shm);
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strcpy(shm, "hello");
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sem_v(semid); /*释放资源*/
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/*清空标准输入缓冲区*/
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while((c=getchar())!='\n' && c!=EOF);
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msg.mtype = 888;
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msg.mtext = 'r'; /*发送消息通知服务器读数据*/
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msgsnd(msqid, &msg, sizeof(msg.mtext), 0);
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break;
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case 'q':
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msg.mtype = 888;
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msg.mtext = 'q';
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msgsnd(msqid, &msg, sizeof(msg.mtext), 0);
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flag = 0;
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break;
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default:
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printf("Wrong input!\n");
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/*清空标准输入缓冲区*/
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while((c=getchar())!='\n' && c!=EOF);
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}
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}
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// 断开连接
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shmdt(shm);
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return 0;
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}
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