进程间通信-套接字 （文件服务器-下载服务器文件目录）

服务器端

#include <stdio.h>#include <stdlib.h>#include <sys/types.h>#include <sys/socket.h>#include <sys/stat.h>#include <unistd.h>#include <errno.h>#include <dirent.h>#include <fcntl.h>#include <arpa/inet.h>#include <netinet/in.h>#include <string.h>#define errmes(mes) do{perror(mes);exit(1);}while(0)#define N 128int do_list(int acceptfd){    DIR *dir;    struct dirent *dirp;    char buf[N] = {};    if((dir = opendir(".")) == NULL)    {        errmes("fail to opendir");    }    while((dirp = readdir(dir)) != NULL)  //让dirp指向读到的目录文件    {        if(dirp->d_name[0] == '.')   //去掉隐藏文件        {            continue;        }        strcpy(buf, dirp->d_name);   //将目录结构体名字放入buf        if(send(acceptfd, buf, N, 0) < 0)        {            errmes("fail to send");        }        usleep(20);    //避免粘包    }    printf("目录文件已发送完毕\n");    close(acceptfd);    return 0;}int main(int argc, const char *argv[]){    int sockfd, acceptfd;    struct sockaddr_in serveraddr, clientaddr;    socklen_t clientlen = sizeof(clientaddr);    char buf[N] = {};    if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)    {        errmes("fail to socket");    }    serveraddr.sin_family = AF_INET;    serveraddr.sin_addr.s_addr = inet_addr(argv[1]);    serveraddr.sin_port =htons(atoi(argv[2]));    if(bind(sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr)) < 0)    {        errmes("fail to bind");    }    if(listen(sockfd, 10) < 0)    {        errmes("fail to listen");    }    while(1)    {        if((acceptfd = accept(sockfd, (struct sockaddr *)&clientaddr, &clientlen)) < 0)        {            errmes("fail to accept");        }        if(recv(acceptfd, buf, N, 0) < 0)        {            errmes("fail to recv");        }        switch (buf[0])        {        case 'L':            do_list(acceptfd);            break;        default:            printf("输入错素\n");            break;        }    }    return 0;}

客户端

#include <stdio.h>#include <stdlib.h>#include <sys/types.h>#include <sys/socket.h>#include <sys/stat.h>#include <unistd.h>#include <errno.h>#include <dirent.h>#include <fcntl.h>#include <arpa/inet.h>#include <netinet/in.h>#include <string.h>#define errmes(mes) do{perror(mes);exit(1);}while(0)#define N 128int do_list(struct sockaddr_in serveraddr){    int sockfd;    char buf[N] = {};    if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)    {        errmes("fail to socket");    }    if(connect(sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr)))    {        errmes("fail to connect");    }    strcpy(buf, "L");    if(send(sockfd, buf, N, 0) < 0)    {        errmes("fail to send");    }    while(recv(sockfd, buf, N, 0) > 0)    {        printf("%s\n",buf);        usleep(15);  //防止粘包    }    printf("目录文件已接收完毕\n");    close(sockfd);    return 0;}int main(int argc, const char *argv[]){    struct sockaddr_in serveraddr;    char buf[N] = {};    serveraddr.sin_family = AF_INET;    serveraddr.sin_addr.s_addr = inet_addr(argv[1]);    serveraddr.sin_port =htons(atoi(argv[2]));    fgets(buf, N, stdin);    buf[strlen(buf) - 1] = '\0';  //由于fgets函数会将终端输入结束符“\n”也当做字符读入到数组中去，                                   //所以要将数组最后一个元素“\n”替换成字符串结束符"\0"，    if(strncmp(buf, "list", 4) == 0)    {        do_list(serveraddr);    }    return 0;}