Unix domain socket

Unix domain socket

原文：https://www.cnblogs.com/sparkdev/p/8359028.html

UNIX Domain Socket是在socket架构上发展起来的用于同一台主机的进程间通讯（IPC），它不需要经过网络协议栈，不需要打包拆包、计算校验和、维护序号和应答等，只是将应用层数据从一个进程拷贝到另一个进程。UNIX Domain Socket有SOCK_DGRAM或SOCK_STREAM两种工作模式，类似于UDP和TCP，但是面向消息的UNIX Domain Socket也是可靠的，消息既不会丢失也不会顺序错乱。

#include <stdlib.h>  

#include <stdio.h>  

#include <stddef.h>  

#include <sys/socket.h>  

#include <sys/un.h>  

#include <errno.h>  

#include <string.h>  

#include <unistd.h>  

#include <ctype.h>   

#define MAXLINE 80  

char *socket_path = "server.socket";  

int main(void)  

{  

    struct sockaddr_un serun, cliun;  

    socklen_t cliun_len;  

    int listenfd, connfd, size;  

    char buf[MAXLINE];  

    int i, n;  

    if ((listenfd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {  

        perror("socket error");  

        exit(1);  

    }  

    memset(&serun, 0, sizeof(serun));  

    serun.sun_family = AF_UNIX;  

    strcpy(serun.sun_path, socket_path);  

    size = offsetof(struct sockaddr_un, sun_path) + strlen(serun.sun_path);  

    unlink(socket_path);  

    if (bind(listenfd, (struct sockaddr *)&serun, size) < 0) {  

        perror("bind error");  

        exit(1);  

    }  

    printf("UNIX domain socket bound ");  

      

    if (listen(listenfd, 20) < 0) {  

        perror("listen error");  

        exit(1);          

    }  

    printf("Accepting connections ... ");  

    while(1) {  

        cliun_len = sizeof(cliun);         

        if ((connfd = accept(listenfd, (struct sockaddr *)&cliun, &cliun_len)) < 0){  

            perror("accept error");  

            continue;  

        }  

          

        while(1) {  

            n = read(connfd, buf, sizeof(buf));  

            if (n < 0) {  

                perror("read error");  

                break;  

            } else if(n == 0) {  

                printf("EOF ");  

                break;  

            }  

              

            printf("received: %s", buf);  

            for(i = 0; i < n; i++) {  

                buf[i] = toupper(buf[i]);  

            }  

            write(connfd, buf, n);  

        }  

        close(connfd);  

    }  

    close(listenfd);  

    return 0;  

}

#include <stdlib.h>  

#include <stdio.h>  

#include <stddef.h>  

#include <sys/socket.h>  

#include <sys/un.h>  

#include <errno.h>  

#include <string.h>  

#include <unistd.h>  

#define MAXLINE 80  

char *server_path = "server.socket";  

int main() {  

    struct  sockaddr_un serun;  

    int len;  

    char buf[100];  

    int sockfd, n;  

    if ((sockfd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0){  

        perror("client socket error");  

        exit(1);  

    }   

    memset(&serun, 0, sizeof(serun));  

    serun.sun_family = AF_UNIX;  

    strcpy(serun.sun_path, server_path);  

    len = offsetof(struct sockaddr_un, sun_path) + strlen(serun.sun_path);  

    if (connect(sockfd, (struct sockaddr *)&serun, len) < 0){  

        perror("connect error");  

        exit(1);  

    }  

    while(fgets(buf, MAXLINE, stdin) != NULL) {    

         write(sockfd, buf, strlen(buf));    

         n = read(sockfd, buf, MAXLINE);    

         if ( n < 0 ) {    

            printf("the other side has been closed. ");    

         }else {    

            write(STDOUT_FILENO, buf, n);    

         }    

    }   

    close(sockfd);  

    return 0;  

}