#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/select.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <assert.h>
#define ipaddr “127.0.0.1”
#define port 8787
#define maxline 1024
#define listenq 5
#define size 10
typedef struct server_context_st
{
int cli_cnt; /*客户端个数*/
int clifds[size]; /*客户端的个数*/
fd_set allfds; /*句柄集合*/
int maxfd; /*句柄最大值*/
} server_context_st;
static server_context_st *s_srv_ctx = null;
/*===========================================================================
* ==========================================================================*/
static int create_server_proc(const char* ip,int port)
{
int fd;
struct sockaddr_in servaddr;
fd = socket(af_inet, sock_stream,0);
if (fd == -1) {
fprintf(stderr, “create socket fail,erron:%d,reason:%s\n”,
errno, strerror(errno));
return -1;
}
/*一个端口释放后会等待两分钟之后才能再被使用,so_reuseaddr是让端口释放后立即就可以被再次使用。*/
int reuse = 1;
if (setsockopt(fd, sol_socket, so_reuseaddr, &reuse, sizeof(reuse)) == -1) {
return -1;
}
bzero(&servaddr,sizeof(servaddr));
servaddr.sin_family = af_inet;
inet_pton(af_inet,ip,&servaddr.sin_addr);
servaddr.sin_port = htons(port);
if (bind(fd,(struct sockaddr*)&servaddr,sizeof(servaddr)) == -1) {
perror(“bind error: “);
return -1;
}
listen(fd,listenq);
return fd;
}
static int accept_client_proc(int srvfd)
{
struct sockaddr_in cliaddr;
socklen_t cliaddrlen;
cliaddrlen = sizeof(cliaddr);
int clifd = -1;
printf(“accpet clint proc is called.\n”);
accept:
clifd = accept(srvfd,(struct sockaddr*)&cliaddr,&cliaddrlen);
if (clifd == -1) {
if (errno == eintr) {
goto accept;
} else {
fprintf(stderr, “accept fail,error:%s\n”, strerror(errno));
return -1;
}
}
fprintf(stdout, “accept a new client: %s:%d\n”,
inet_ntoa(cliaddr.sin_addr),cliaddr.sin_port);
//将新的连接描述符添加到数组中
int i = 0;
for (i = 0; i < size; i++) {
if (s_srv_ctx->clifds[i] < 0) {
s_srv_ctx->clifds[i] = clifd;
s_srv_ctx->cli_cnt++;
break;
}
}
if (i == size) {
fprintf(stderr,”too many clients.\n”);
return -1;
}
101 }
static int handle_client_msg(int fd, char *buf)
{
assert(buf);
printf(“recv buf is :%s\n”, buf);
write(fd, buf, strlen(buf) +1);
return 0;
}
static void recv_client_msg(fd_set *readfds)
{
int i = 0, n = 0;
int clifd;
char buf[maxline] = {0};
for (i = 0;i <= s_srv_ctx->cli_cnt;i++) {
clifd = s_srv_ctx->clifds[i];
if (clifd < 0) {
continue;
}
/*判断客户端套接字是否有数据*/
if (fd_isset(clifd, readfds)) {
//接收客户端发送的信息
n = read(clifd, buf, maxline);
if (n <= 0) {
/*n==0表示读取完成,客户都关闭套接字*/
fd_clr(clifd, &s_srv_ctx->allfds);
close(clifd);
s_srv_ctx->clifds[i] = -1;
continue;
}
handle_client_msg(clifd, buf);
}
}
}
static void handle_client_proc(int srvfd)
{
int clifd = -1;
int retval = 0;
fd_set *readfds = &s_srv_ctx->allfds;
struct timeval tv;
int i = 0;
while (1) {
/*每次调用select前都要重新设置文件描述符和时间,因为事件发生后,文件描述符和时间都被内核修改啦*/
fd_zero(readfds);
/*添加监听套接字*/
fd_set(srvfd, readfds);
s_srv_ctx->maxfd = srvfd;
tv.tv_sec = 30;
tv.tv_usec = 0;
/*添加客户端套接字*/
for (i = 0; i < s_srv_ctx->cli_cnt; i++) {
clifd = s_srv_ctx->clifds[i];
/*去除无效的客户端句柄*/
if (clifd != -1) {
fd_set(clifd, readfds);
}
s_srv_ctx->maxfd = (clifd > s_srv_ctx->maxfd ? clifd : s_srv_ctx->maxfd);
}
/*开始轮询接收处理服务端和客户端套接字*/
retval = select(s_srv_ctx->maxfd + 1, readfds, null, null, &tv);
if (retval == -1) {
fprintf(stderr, “select error:%s.\n”, strerror(errno));
return;
}
if (retval == 0) {
fprintf(stdout, “select is timeout.\n”);
continue;
}
if (fd_isset(srvfd, readfds)) {
/*监听客户端请求*/
accept_client_proc(srvfd);
} else {
/*接受处理客户端消息*/
recv_client_msg(readfds);
}
}
}
static void server_uninit()
{
if (s_srv_ctx) {
free(s_srv_ctx);
s_srv_ctx = null;
}
}
static int server_init()
{
s_srv_ctx = (server_context_st *)malloc(sizeof(server_context_st));
if (s_srv_ctx == null) {
return -1;
}
memset(s_srv_ctx, 0, sizeof(server_context_st));
int i = 0;
for (;i < size; i++) {
s_srv_ctx->clifds[i] = -1;
}
return 0;
}
int main(int argc,char *argv[])
{
int srvfd;
/*初始化服务端context*/
if (server_init() < 0) {
return -1;
}
/*创建服务,开始监听客户端请求*/
srvfd = create_server_proc(ipaddr, port);
if (srvfd < 0) {
fprintf(stderr, “socket create or bind fail.\n”);
goto err;
}
/*开始接收并处理客户端请求*/
handle_client_proc(srvfd);
server_uninit();
return 0;
err:
server_uninit();
return -1;
}