unix domain socket 通信实例

下面是一个简单的 Unix Domain Socket 通信实例，包括了服务端和客户端代码：

服务端代码：

#include <sys/socket.h>
#include <sys/un.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#define SOCK_PATH "/tmp/echo_socket"

int main(int argc, char *argv[]) {
    int s, s2, len;
    struct sockaddr_un local, remote;
    char str[100];

    if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
        perror("socket");
        exit(1);
    }

    local.sun_family = AF_UNIX;
    strcpy(local.sun_path, SOCK_PATH);
    unlink(local.sun_path);
    len = strlen(local.sun_path) + sizeof(local.sun_family);
    if (bind(s, (struct sockaddr *)&local, len) == -1) {
        perror("bind");
        exit(1);
    }

    if (listen(s, 5) == -1) {
        perror("listen");
        exit(1);
    }

    printf("Waiting for a connection...\n");
    while (1) {
        int done, n;
        unsigned int t;

        t = sizeof(remote);
        if ((s2 = accept(s, (struct sockaddr *)&remote, &t)) == -1) {
            perror("accept");
            exit(1);
        }

        printf("Connected.\n");

        done = 0;
        do {
            n = recv(s2, str, 100, 0);
            if (n <= 0) {
                if (n < 0) perror("recv");
                done = 1;
            }

            if (!done) {
                if (send(s2, str, n, 0) < 0) {
                    perror("send");
                    done = 1;
                }
            }
        } while (!done);

        close(s2);
    }

    return 0;
}

客户端代码：

#include <sys/socket.h>
#include <sys/un.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#define SOCK_PATH "/tmp/echo_socket"

int main(int argc, char *argv[]) {
    int s, len;
    struct sockaddr_un remote;
    char *str = "hello, world!";

    if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
        perror("socket");
        exit(1);
    }

    remote.sun_family = AF_UNIX;
    strcpy(remote.sun_path, SOCK_PATH);
    len = strlen(remote.sun_path) + sizeof(remote.sun_family);
    if (connect(s, (struct sockaddr *)&remote, len) == -1) {
        perror("connect");
        exit(1);
    }

    if (send(s, str, strlen(str), 0) == -1) {
        perror("send");
        exit(1);
    }

    if (recv(s, str, strlen(str), 0) == -1) {
        perror("recv");
        exit(1);
    }

    printf("Received: %s\n", str);

    close(s);

    return 0;
}

服务端代码创建了一个 Unix Domain Socket 并监听，一旦有客户端连接进来，服务端就接收客户端发送的数据，并将其原样返回。客户端代码连接到服务端，并发送一个字符串，然后等待服务端返回数据并打印。