一个tcp的客户端服务器程序
服务器端不变，客户端通过I/O复用轮询键盘输入与socket输入（接收客户端的信息）
服务器端：
1 /*selcet服务器客户端模型:
2 1.客户端关闭后，服务器再向客户端发送信息，第一次会收到一个RST复位报文，第二次会收到SIGPIPE信号，导致服务器关闭，必须对这个信号进行处理：
3 1.在服务器对read返回值为0的情况进行处理，不向客户端发送信息
4 2.signal函数: signal(SIGPIPE, handle) 或者直接忽略signal(SIGPIPE, SIG_IGN)
5 */
6 #include <stdio.h>
7 #include <stdlib.h>
8 #include <string.h>
9 #include <unistd.h>
10 #include <errno.h>
11 #include <sys/types.h>
12 #include <sys/stat.h>
13 #include <sys/socket.h>
14 #include <arpa/inet.h>
15 #include <signal.h>
16
17 #define ERR_EXIT(m) 18 do { 19 perror(m);20 exit(EXIT_FAILURE);21 }while(0)//宏定义的错误处理
22
23 static void do_service(int fd)
24 {
25 char recvbuf[1024] = {0};
26 int ret;
27 while(1)
28 {
29 memset(recvbuf, 0, sizeof recvbuf);
30 ret = read(&rt, recvbuf, 1024);
31 sleep(3);
32 if(ret == 0)//关闭客户端时会导致ret == 0
33 printf("no message\n");
34 else if(ret == -1)
35 {
36 if(errno == EINTR)
37 continue;
38 return ;
39 }
40 rio_writen(fd, recvbuf, 5);
41 }
42 }
43
44 void handle(int signum)//SIGPIPE信号处理函数
45 {
46 printf("hello\n");
47 }
48
49 int main(int argc, const char *argv[])
50 {
51 if(signal(SIGPIPE, handle) == SIG_ERR)
52 ERR_EXIT("signal");
53
54 int listenfd = socket(AF_INET, SOCK_STREAM, 0);//准备一个socketfd
55 if(listenfd == -1 )
56 ERR_EXIT("listen");
57
58 int on = 1;
59 if(setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)//setsockopt设置端口复用
60 {
61 close(listenfd);
62 ERR_EXIT("setsockopt");
63 }
64
65 struct sockaddr_in seraddr;
66 seraddr.sin_family = AF_INET;
67 seraddr.sin_port = htons(8888);
68 seraddr.sin_addr.s_addr = htonl(INADDR_ANY);
69 socklen_t len = sizeof(seraddr);
70 if(bind(listenfd, (struct sockaddr*)&seraddr, len) == -1)//监听socket端口，
71 {
72 close(listenfd);
73 ERR_EXIT("bind");
74 }
75 //上述过程可以封装到起来，不用全部写入main
76 if(listen(listenfd, 6) == -1)
77 {
78 close(listenfd);
79 ERR_EXIT("listen");
80 }
81
82 struct sockaddr_in cliaddr;
83 bzero(&cliaddr, sizeof(cliaddr));
84 socklen_t cli_len = sizeof cliaddr;
85
86 int clientfd;
87 clientfd = accept(listenfd, (struct sockaddr*)&cliaddr, &cli_len);
88
89 if(clientfd == -1)
90 {
91 close(listenfd);
92 ERR_EXIT("accept");
93 }
94 do_service(clientfd);
95
96 close(clientfd);
97 close(listenfd);
98 return 0;
99 }
1.select客户端:
1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <string.h>
4 #include <errno.h>
5 #include <sys/types.h>
6 #include <sys/socket.h>
7 #include <netinet/in.h>
8 #include <arpa/inet.h>
9 #include <sys/select.h>
10
11 #define ERR_EXIT(m) 12 do { 13 perror(m);14 exit(EXIT_FAILURE);15 }while(0)
16
17 static void do_client(int fd)
18 {
19 char recvbuf[MAXLINE + 1] = {0};
20 char sendbuf[MAXLINE + 1] = {0};
21
22 fd_set reade, ready;//将ready集合放入select轮询，每次轮询前将reade赋值给ready
23 FD_ZERO(&reade);//清空reade集合
24 int fd_stdin = fileno(stdin);
25 FD_SET(fd_stdin, &reade);
26 FD_SET(fd, &reade);//将需要监听的文件描述符加入集合
27 int fd_max = (fd_stdin > fd) ? fd_stdin : fd;//select轮询的最大文件描述符
28
29 int ret;
30 while(1)
31 {
32 ready = reade;
33 ret = select( fd_max+1, &ready, NULL, NULL, NULL);//轮询，最后一个参数struct *timeval设置为NULL表示即时轮询（每次轮询间没时间间隔）
34 if(ret < 0)
35 {
36 if(errno == EINTR)
37 continue;
38 ERR_EXIT("select");
39 }else if(ret == 0)//监听的文件描述符状态未发生变化
40 {
41 continue;
42 }
43
44 if(FD_ISSET(fd_stdin, &ready))
45 {
46 if(fgets(sendbuf, sizeof(sendbuf), stdin) == NULL)
47 {
48 shutdown(fd, SHUT_WR);//关闭fd的写端，close关闭时关闭整个描述符,若再写的话会导致write返回-1，系统会向客户端进程发送一个SIGPIPE信号， 导致关闭，可以对信号进行signal(SIGPIPE, SIG_IGN)处理，也可将fd_stdin从监听队列删除
49 // close(fd);
50 exit(EXIT_SUCCESS);
51 //break;52 }else
53 write(fd, sendbuf, strlen(sendbuf));
54 }
55
56 if(FD_ISSET(fd, &ready))
57 {
58 int nread = read(fd, recvbuf, MAXLINE);
59 if(nread < 0)
60 ERR_EXIT("read");
61 if(nread == 0)//如果没接收到消息，打印关闭描述符，退出循环
62 {
63 fprintf(stdout, "fd close\n");
64 break;
65 }
66 fprintf(stdout, "receive:%s\n", recvbuf);//注意要刷新
67 }
68 memset(recvbuf, 0, sizeof recvbuf);
69 memset(sendbuf, 0, sizeof sendbuf);
70 }
71 }
72
73 int main(int argc, const char *argv[])
74 {
75 int fd = socket(AF_INET, SOCK_STREAM, 0);
76 if(fd < 0)
77 ERR_EXIT("socket");
78
79 struct sockaddr_in cliaddr;
80 cliaddr.sin_family = AF_INET;
81 cliaddr.sin_port = htons(8888);
82 cliaddr.sin_addr.s_addr = inet_addr("127.0.0.1");
83 socklen_t len = sizeof cliaddr;
84
85 int ret ;
86 if((ret = connect(fd, (struct sockaddr*)&cliaddr, len)) == -1)
87 {
88 close(fd);
89 ERR_EXIT("connect");
90 }
91 do_client(fd);
92 close(fd);
93 printf("123\n");
94 return 0;
95 }
2.poll客户端：
static void do_client(int fd)
{
char recvbuf[MAXLINE + 1] = {0};
char sendbuf[MAXLINE + 1] = {0};
struct pollfd pfd[2];//struct pollfd数组，里面存放监听描述符相关信息，供poll轮询使用
pfd[0].fd = fileno(stdin);
pfd[0].events = POLLIN;
pfd[1].fd = fd;
pfd[1].events = POLLIN;
int ret;
while(1)
{
ret = poll( pfd, 2, -1);//轮询，-1和select中的时间结构体指针为NULL的效果一样
if(ret < 0)
{
if(errno == EINTR)
continue;
ERR_EXIT("select");
}else if(ret == 0)
{
continue;
}
if(pfd[0].revents & POLLIN)
{
if(fgets(sendbuf, sizeof(sendbuf), stdin) == NULL)
{
shutdown(fd, SHUT_WR);//关闭fd的写端
pfd[0].fd = -1;
}else
write(fd, sendbuf, strlen(sendbuf));
}
if(pfd[1].revents & POLLIN)
{
int nread = read(fd, recvbuf, MAXLINE);
if(nread < 0)
ERR_EXIT("read");
if(nread == 0)//如果没接收到消息，打印关闭描述符，退出循环
{
fprintf(stdout, "fd close\n");
break;
}
fprintf(stdout, "receive:%s\n", recvbuf);//注意要刷新
}
memset(recvbuf, 0, sizeof recvbuf);
memset(sendbuf, 0, sizeof sendbuf);
}
}
//其余部分和select中一样
3.epoll客户端
static void do_client(int fd)
{
char recvbuf[MAXLINE + 1] = {0};
char sendbuf[MAXLINE + 1] = {0};
int epollfd = epoll_create(2);//返回值也是一个文件描述符，记得要关闭，不然会导致fd耗尽
if(epollfd == -1)
ERR_EXIT("epoll_create");
struct epoll_event events[2];
struct epoll_event ev;
int ret;
ev.data.fd = fd;
ev.events = EPOLLIN;
ret = epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &ev);//注册fd
if(ret == -1)
ERR_EXIT("epoll_ctl");
ev.data.fd = fileno(stdin);
ev.events = EPOLLIN;
ret = epoll_ctl(epollfd, EPOLL_CTL_ADD, STDIN_FILENO, &ev);//注册fd
if(ret == -1)
ERR_EXIT("epoll_ctl");
int nready;
while(1)
{
nready = epoll_wait(epollfd, events, 2, -1);
if(nready < 0)
{
if(errno == EINTR)
continue;
ERR_EXIT("select");
}else if(nready == 0)
{
continue;
}
int i;
for(i = 0; i < nready; i++)
{
int nfd = events[i].data.fd;
if(nfd == STDIN_FILENO)
{
if(fgets(sendbuf, 1024, stdin) == NULL)
{
shutdown(fd, SHUT_WR);
struct epoll_event ee;
ee.data.fd = STDIN_FILENO;
if(epoll_ctl(epollfd, EPOLL_CTL_DEL, STDIN_FILENO, &ee) == -1)
ERR_EXIT("epoll_ctl");
}else
write(fd, sendbuf, strlen(sendbuf));
}
if(nfd == fd)
{
int ret = read(fd, recvbuf, 1024);
if(ret == -1)
ERR_EXIT("readline");
else if(ret == -1)
{
close(fd);
printf("fd close\n");
exit(EXIT_SUCCESS);
}
printf("recv data :%s\n", recvbuf);
}
}
}
memset(recvbuf, 0, sizeof recvbuf);
memset(sendbuf, 0, sizeof sendbuf);
}
I/O复用的 select poll和epoll的简单实现,布布扣,bubuko.com
时间： 2024-03-24 00:25:03