Linux网络编程 基于TCP的多进程

客户端代码：

#include <stdio.h>  #include <stdlib.h>  #include <unistd.h>  #include <string.h>  #include <sys/types.h>  #include <sys/socket.h>  #include <arpa/inet.h>  #include <netinet/in.h>  static usage(const char* proc)  {      printf("%s [ip] [port\n]", proc);  }  int main(int argc, char** argv)  {      if(argc != 3)      {          usage(argv[0]);          exit(1);      }      int sock = socket(AF_INET, SOCK_STREAM, 0);      struct sockaddr_in server;      if(sock < 0)      {          perror("socket");          return 1;      }      server.sin_family = AF_INET;      server.sin_addr.s_addr = inet_addr(argv[1]);      server.sin_port = htons(atoi(argv[2]));      if(connect(sock ,(struct sockaddr*)&server, sizeof(server) ) < 0)      {          perror("connect");          exit(4);      }      char buf[1024];      while(1)      {          printf("please input #: ");          fflush(stdout);          ssize_t sread = read(0, buf, sizeof(buf)-1);          if(sread > 0)          {              buf[sread-1] = 0;              write(sock, buf, strlen(buf));              printf("server $ %s\n", buf);              read(sock, buf, sizeof(buf) - 1);          }      }      close(sock);  }  

服务端#include

#include <sys/types.h>   //  #include <sys/socket.h>  // socket()  bind()  #include <unistd.h>  #include <string.h>  #include <stdlib.h>  #include <arpa/inet.h>  #include <netinet/in.h>  static void usage(const char* proc)  {      printf("use help : %s [local_ip] [local_port]\n", proc);  }  // 创建并绑定一个socket  int startup(const char* _ip, int _port)  {      // 创建一个socket      int sock = socket(AF_INET, SOCK_STREAM, 0);      if (sock < 0)      {          perror("----sock----fail\n");          exit(-1);      }      // 绑定一个本地socket      struct sockaddr_in local;      local.sin_family = AF_INET;      local.sin_addr.s_addr = inet_addr(_ip);      local.sin_port = htons(_port);      if(bind(sock, (struct sockaddr*)&local, sizeof(local)) != 0)      {          perror("---bind---fail\n");          close(sock);          exit(-2);      }      if(listen(sock, 5) != 0)      {          perror("----listen----fail\n");          close(sock);          exit(-1);      }      return sock;          }  int main(int argc, char**argv)  {      if(argc != 3)      {          usage(argv[0]);          return -1;      }      // 获取一个local socket      int listen_sock = startup(argv[1], atoi(argv[2]));      struct sockaddr_in client;      socklen_t len = sizeof(client);      char buf[1024];      while(1)      {          int new_sock = accept(listen_sock,(struct sockaddr*)&client, &len);          if(new_sock < 0)          {              perror("----accept----fail\n");              close(listen_sock);              exit(-5);          }          pid_t id = fork();          if(id == 0)          {              if(fork() > 0)              {                  exit(0);              }               // ///////////////可以再这里fork 然后退出子进程,这样负责监听的进程PID就不会一直变//////////              close(listen_sock); // 子进程已经获得 sockfd， 不需要listen sock所以关闭              while(1)              {                  ssize_t s = read(new_sock,buf, sizeof(buf)-1);                  if(s > 0 )                  {                      buf[s] = 0;                      printf("client say## %s \n", buf);                      write(new_sock, buf, strlen(buf));                  }                  else if( s == 0)                  {                      printf("client quit. \n");                      break;                  }                  else                      break;              }              exit(0);          }          else if (id > 0)          {              // 父进程              // 在父进程中fork退出的话，会导致监听进程的pid一直在变，所以我们也可以再子进程中fork然后退出              close(new_sock); // 此时子进程已经获取 sockfd， 父进程只需要监听sockfd，又因为每次fork都会赋值描述符，为了节省资源，关闭new_sock          }      }      return 0;  }