c - 如何使用unix套接字(AF_UNIX、SOCK_DGRAM)模拟PUB/SUB？

Question

我正在努力让这种简单的沟通发挥作用。

我用 zmq 不到五分钟就搞定了。使用 UNIX 套接字来做这件事很痛苦(显然是因为我缺乏信心)。

这是服务器:

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

#include "streamsocket.h"

char *socket_path = "/tmp/stream";
int socket_fd=0;
struct sockaddr_un addr;

int main(){
        socket_setup();
        while(1){
                socket_sendstr("a");
                sleep(1);
        }
}

void socket_setup(){

  int rc;

  memset(&addr, 0, sizeof(addr));
  addr.sun_family = AF_UNIX;
  strcpy(addr.sun_path, socket_path);

  if ( (socket_fd = socket(AF_UNIX, SOCK_DGRAM, 0)) == -1) {
    perror("socket error");
    exit(-1);
  }

  rc=bind(socket_fd, (struct sockaddr *) &addr, sizeof(addr));
  if(rc<0){
    perror("bind error");
    exit(-2);
  }

}

int socket_sendstr(char* buffer) {
  int len=strlen(buffer);
  // corrected after suggestion in answer below (rc->len)
  // int rc=write(socket_fd, buffer, rc);
  int rc=write(socket_fd, buffer, len);

  if (rc != len) {
      if (rc > 0) fprintf(stderr,"partial write");
      else {
        perror("write error");
        //exit(-1);
      }
  }
}

这是客户端:

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

int main(){
        char * server_filename = "/tmp/stream";
        char * client_filename = "/tmp/stream-client";

        struct sockaddr_un server_addr;
        struct sockaddr_un client_addr;

        int rc;

        memset(&server_addr, 0, sizeof(server_addr));
        server_addr.sun_family = AF_UNIX;
        strncpy(server_addr.sun_path, server_filename, 104); 

        memset(&client_addr, 0, sizeof(client_addr));
        client_addr.sun_family = AF_UNIX;
        strncpy(client_addr.sun_path, client_filename, 104);

        // get socket
        int sockfd = socket(AF_UNIX, SOCK_DGRAM, 0);

        // bind client to client_filename
        rc = bind(sockfd, (struct sockaddr *) &client_addr, sizeof(client_addr));
        if(rc==-1) perror("bind error");

        // connect client to server_filename
        rc = connect(sockfd, (struct sockaddr *) &server_addr, sizeof(server_addr));
        if(rc==-1) perror("connect error");


        char buf[1024];
        int bytes=0;
        while(bytes = read(sockfd, buf, sizeof(buf))){
                printf("%s\n",buf);
        }

        close(sockfd);
}

我做错了什么？

目前客户端没有打印任何内容。

EDIT1:将服务器 write( , ,rc) 中错误的“rc”纠正为 write( , ,len)

编辑2:由于客户端无法工作，因此: socat UNIX-CLIENT:/tmp/stream -

所以我认为问题可能出在服务器上。

Answer 1

int len=strlen(buffer);
  int rc=write(socket_fd, buffer, rc);

不写期望获得第三个参数长度；