Linux_C socket server.c clinet.c功能分开写

socklib.h
1 int make_server_socket(int );
2 int connect_to_server(char* , int );
3 int process_request(int );
4 int talk_with_server(int );

  1 /* socklib.c
  2  * This file contains functions used lots when writing internet
  3  * client/ server programs.    The two main functions here are:
  4  * 
  5  * int make_server_socket(portnum) returns a server socket 
  6  *                                       or -1 if error
  7  * int make_server_socket_q(portnum, backlog)
  8  * 
  9  * int connect_to_server(char* hostname, int portnum) return a connected socket
 10  *                                       or -1 if error
 11  */
 12 #include <stdio.h>
 13 #include <unistd.h>
 14 #include <sys/socket.h>
 15 #include <sys/types.h>
 16 #include <netinet/in.h>
 17 #include <netdb.h>
 18 #include <time.h>
 19 #include <strings.h>
 20 
 21 #define HOSTLEN 256
 22 #define BACKLOG 1
 23 #define oops(msg) {perror(msg); exit(1);}
 24 
 25 int make_server_socket_q(int , int);
 26 
 27 int make_server_socket(int portnum) {
 28   return make_server_socket_q(portnum, BACKLOG);
 29 }
 30 
 31 int make_server_socket_q(int portnum, int backlog) {
 32   struct sockaddr_in saddr;
 33   struct hostent *hp;
 34   char hostname[HOSTLEN];
 35   int sock_id;
 36   sock_id=socket(PF_INET, SOCK_STREAM, 0);
 37   if(sock_id == -1)
 38     return -1;
 39   /*bulid socket bind*/
 40   bzero((void*)&saddr, sizeof(saddr));
 41   gethostname(hostname, HOSTLEN);
 42   hp=gethostbyname(hostname);
 43   
 44   bcopy((void*)hp->h_addr, (void*)&saddr.sin_addr, hp->h_length);
 45   saddr.sin_port=htons(portnum);
 46   saddr.sin_family=AF_INET;
 47   if(bind(sock_id, (struct sockaddr*)&saddr, sizeof(saddr))!=0)
 48     return -1;
 49 
 50   /** arrange for incoming calls **/
 51   if(listen(sock_id, backlog)!=0)
 52     return -1;
 53   return sock_id;
 54 }
 55 
 56 int connect_to_server(char *host, int portnum) {
 57   int sock;
 58   struct sockaddr_in servadd;
 59   struct hostent *hp;
 60   /** Step1: get a socket**/
 61   sock=socket(AF_INET, SOCK_STREAM, 0);
 62   if(sock==-1)
 63     return -1;
 64   /**Step2: connect to server**/
 65   bzero((void*)&servadd, sizeof(servadd));
 66   hp=gethostbyname(host);
 67   if(hp==NULL)
 68     return -1;
 69   bcopy(hp->h_addr, (struct sockaddr*)&servadd.sin_addr, hp->h_length);
 70   servadd.sin_port=htons(portnum);
 71   servadd.sin_family=AF_INET;
 72   if(connect(sock, (struct sockaddr* )&servadd, sizeof(servadd))!=0)
 73     return -1;
 74   return sock; 
 75 }
 76 
 77 int talk_with_server(int fd) {
 78   char buf[BUFSIZ];
 79   int len;
 80   len = read(fd, buf, BUFSIZ);
 81   if(len==-1)
 82     return -1;
 83   if(write(1, buf, len)!=len)
 84     return -1;
 85   return 0;
 86 }
 87 /*
 88 int process_request(int fd) {
 89   time_t thetime;
 90   char *cp;
 91   time(&thetime);
 92   cp=ctime(&thetime);
 93   if(write(fd, cp, strlen(cp)) != strlen(cp))
 94     return -1;
 95   return 0;
 96 }
 97 */
 98 int process_request(int fd) {
 99   int pid = fork();
100   switch(pid) {
101   case -1: return -1;
102   case 0: dup2(fd, 1);
103     close(fd);
104     execl("/bin/date", "date", NULL);
105     oops("execl");
106   default:wait(NULL);
107   }
108 }

/* timeclnt_new.c - a new client for use the socklib.c
 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <time.h>
#include <strings.h>
#include "socklib.h"

#define oops(msg) {perror(msg); exit(1);}

int main(int argc, char* argv[]){
  int sock_id;
  sock_id=connect_to_server(argv[1],atoi(argv[2]));
  if(sock_id==-1)
    oops("connect_to_server");
  if(talk_with_server(sock_id) == -1)
    oops("talk_to_server");
  close(sock_id);
  return 0;
}

 1 #include <stdio.h>
 2 #include <unistd.h>
 3 #include <sys/types.h>
 4 #include <sys/socket.h>
 5 #include <netinet/in.h>
 6 #include <netdb.h>
 7 #include <time.h>
 8 #include <strings.h>
 9 #include "socklib.h"
10 
11 #define oops(msg){ perror(msg); exit(1);}
12 #define PORTNUM 13000
13 int main(void ) {
14   int sockid, fd;
15   sockid=make_server_socket(PORTNUM);
16   if(sockid==-1)
17     oops("make_server_socket");
18   while(1){
19     fd=accept(sockid, NULL, NULL);
20     if(fd==-1)
21       break;
22     process_request(fd);
23     close(fd);
24   }
25   return 0;
26 }