client.c

UNIX/Linux环境下使用UNIX domain协议实现的客户端和服务器端程序

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

#define BUFFER_SIZE	1024

int main(int argc, char **argv)
{
  int fd;

  if (argc < 2)
  {
    fprintf(stdout, "Usage: %s <path>\n", argv[0]);
    exit(1);
  }

  // XXX: step 1, socket();
  //int socket(int domain, int type, int protocol);
  if ((fd = socket(PF_LOCAL, SOCK_STREAM, 0)) < 0)
  {
    fprintf(stderr, "socket() failed: %s\n", strerror(errno));
    exit(1);
  }

  // XXX: step 2, bind() (optional)
  // XXX: step 3, connect()
  struct sockaddr_un remote_address;

#if 0
  struct sockaddr_un
  {
    sa_family_t sun_family;
    char sun_path[108];
  }
#endif

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

  remote_address.sun_family = PF_LOCAL;
  memcpy(remote_address.sun_path, argv[1], strlen(argv[1]));

  //int connect(int sockfd, const struct sockaddr *serv_addr, socklen_t addrlen);
  if (connect(fd, (struct sockaddr *) &remote_address, sizeof(remote_address)) < 0)
  {
    fprintf(stderr, "connect() failed: %s\n", strerror(errno));
    // FIXME: 
    close(fd);
    exit(1);
  }

  // XXX: step 4, r/w
  char buffer[BUFFER_SIZE];
  ssize_t n;

again:
  //ssize_t read(int fd, void *buf, size_t count);
  if ((n = read(fd, buffer, BUFFER_SIZE)) < 0)
  {
    if (errno == EINTR)
    {
      goto again;
    }
    else
    {
      fprintf(stderr, "read() failed: %s\n", strerror(errno));
      // FIXME:
      close(fd);
      exit(1);
    }
  }
  else if (n == 0)
  {
    fprintf(stdout, "Connection closed by peer.\n");
  }
  else
  {
    buffer[n] = '\0';
    fprintf(stdout, "read %d bytes from peer: %s\n", n, buffer);
  }

  // XXX: step 5, close()
  close(fd);

  return 0;
}