直接上TCP Server源码：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/socket.h>
#include <sys/epoll.h>
#include <sys/types.h>
#include <sys/resource.h> /*setrlimit */
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <assert.h>
#include <signal.h>
#include <pthread.h>
#define IPADDRESS "127.0.0.1"
#define PORT 8011
#define MAXSIZE 1024
#define LISTENQ 5
#define FDSIZE 50000
#define EPOLLEVENTS 100
int stop_server = 0;
//函数声明
//创建套接字并进行绑定
static int socket_bind(const char* ip,int port);
//IO多路复用epoll
static void do_epoll(int listenfd);
//事件处理函数
static void handle_events(int epollfd,struct epoll_event *events,int num,int listenfd,char *buf);
//处理接收到的连接
static void handle_accpet(int epollfd,int listenfd);
//读处理
static void do_read(int epollfd,int fd,char *buf);
//写处理
static void do_write(int epollfd,int fd,char *buf);
//添加事件
static void add_event(int epollfd,int fd,int state);
//修改事件
static void modify_event(int epollfd,int fd,int state);
//删除事件
static void delete_event(int epollfd,int fd,int state);
//other
static int do_error(int fd, int *error);
static int setnonblocking(int fd);
static void daemonize(void);
static int set_fdlimit();
static void signal_exit_handler();
static void signal_exit_func(int signo);
int main(int argc,char *argv[])
{
//设置每个进程允许打开的最大文件数,socket
if (set_fdlimit() < 0)
{
return -1;
}
int background = 0;
if (background)
{
daemonize();
}
//设置信号处理,SIG_IGN表示忽略信号,SIG_DFL表示使用信号的默认处理方式
//signal(SIGHUP, SIG_IGN); //开启的话，就捕获不到终端窗口关闭的信号了。即窗口关闭，进程仍然进行。
signal(SIGPIPE, SIG_IGN);
/*
if (argc != 2) {
fprintf(stderr, "Usage: %s port\n", argv[0]);
return 1;
}
int port = atoi(argv[1]);*/
int listenfd;
listenfd = socket_bind(IPADDRESS,PORT);
listen(listenfd,LISTENQ);
printf("start listening...\n");
signal_exit_handler();
do_epoll(listenfd);
return 0;
}
static int socket_bind(const char* ip,int port)
{
int listenfd;
struct sockaddr_in servaddr;
listenfd = socket(AF_INET,SOCK_STREAM,0);
if (listenfd == -1)
{
perror("socket error:");
exit(1);
}
bzero(&servaddr,sizeof(servaddr));
servaddr.sin_family = AF_INET;
//inet_pton(AF_INET,ip,&servaddr.sin_addr);
servaddr.sin_port = htons(port);
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
int error;
int reuse = 1;
int ret = setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse));
if (ret == -1)
{
return do_error(listenfd, &error);
}
if (bind(listenfd,(struct sockaddr*)&servaddr,sizeof(servaddr)) == -1)
{
perror("bind error: ");
exit(1);
}
return listenfd;
}
static void do_epoll(int listenfd)
{
int epollfd;
struct epoll_event events[EPOLLEVENTS];
int ret;
char buf[MAXSIZE];
memset(buf,0,MAXSIZE);
//创建一个描述符
int error;
epollfd = epoll_create(1024);//1024 is just a hint for the kernel
if (epollfd == -1)
{
return do_error(epollfd, &error);
}
//添加监听描述符事件
add_event(epollfd,listenfd,EPOLLIN);
while ( stop_server == 0 )
{
//获取已经准备好的描述符事件
ret = epoll_wait(epollfd,events,EPOLLEVENTS,-1);
handle_events(epollfd,events,ret,listenfd,buf);
}
close(epollfd);
}
static void handle_events(int epollfd,struct epoll_event *events,int num,int listenfd,char *buf)
{
int i;
int fd;
//进行选好遍历
for (i = 0;i < num;i++)
{
fd = events[i].data.fd;
//根据描述符的类型和事件类型进行处理
if ((fd == listenfd) &&(events[i].events & EPOLLIN))
handle_accpet(epollfd,listenfd);
else if (events[i].events & EPOLLIN)
do_read(epollfd,fd,buf);
else if (events[i].events & EPOLLOUT)
do_write(epollfd,fd,buf);
}
}
static void handle_accpet(int epollfd,int listenfd)
{
int clifd;
struct sockaddr_in cliaddr;
socklen_t cliaddrlen = sizeof(cliaddr);
clifd = accept(listenfd,(struct sockaddr*)&cliaddr,&cliaddrlen);
if (clifd == -1)
perror("accpet error:");
else
{
printf("accept a new client: %s:%d\n",inet_ntoa(cliaddr.sin_addr),cliaddr.sin_port);
//添加一个客户描述符和事件
add_event(epollfd,clifd,EPOLLIN);
}
}
static void do_read(int epollfd,int fd,char *buf)
{
int nread;
nread = read(fd,buf,MAXSIZE);
if (nread == -1)
{
perror("read error:");
close(fd);
delete_event(epollfd,fd,EPOLLIN);
}
else if (nread == 0)
{
fprintf(stderr,"client close,fd=%d\n",fd);
close(fd);
delete_event(epollfd,fd,EPOLLIN);
}
else
{
printf("read message is: %s,fd=%d\n",buf,fd);
//修改描述符对应的事件，由读改为写
modify_event(epollfd,fd,EPOLLOUT);
}
}
static void do_write(int epollfd,int fd,char *buf)
{
int nwrite;
nwrite = write(fd,buf,strlen(buf));
if (nwrite == -1)
{
perror("write error:");
close(fd);
delete_event(epollfd,fd,EPOLLOUT);
}
else
modify_event(epollfd,fd,EPOLLIN);
memset(buf,0,MAXSIZE);
}
static void add_event(int epollfd,int fd,int state)
{
struct epoll_event ev;
ev.events = state;
ev.data.fd = fd;
epoll_ctl(epollfd,EPOLL_CTL_ADD,fd,&ev);
setnonblocking(fd);
}
static void delete_event(int epollfd,int fd,int state)
{
struct epoll_event ev;
ev.events = state;
ev.data.fd = fd;
epoll_ctl(epollfd,EPOLL_CTL_DEL,fd,&ev);
}
static void modify_event(int epollfd,int fd,int state)
{
struct epoll_event ev;
ev.events = state;
ev.data.fd = fd;
epoll_ctl(epollfd,EPOLL_CTL_MOD,fd,&ev);
}
static int do_error(int fd, int *error)
{
fprintf(stderr, "error: %s\n", strerror(errno));
*error = errno;
while ((close(fd) == -1) && (errno == EINTR));
errno = *error;
return 1;
}
static int setnonblocking(int fd)
{
int old_option = fcntl(fd, F_GETFL);
int new_option = old_option | O_NONBLOCK;
fcntl(fd, F_SETFL, new_option);
return old_option;
}
static void daemonize(void) { //come from /redis/server.c/daemonize()
int fd;
if (fork() != 0) exit(0); /* parent exits */
setsid(); /* create a new session */
/* Every output goes to /dev/null. If Redis is daemonized but
* the 'logfile' is set to 'stdout' in the configuration file
* it will not log at all. */
if ((fd = open("/dev/null", O_RDWR, 0)) != -1) {
dup2(fd, STDIN_FILENO);
dup2(fd, STDOUT_FILENO);
dup2(fd, STDERR_FILENO);
if (fd > STDERR_FILENO) close(fd);
}
}
static int set_fdlimit()
{
//设置每个进程允许打开的最大文件数
//这项功能等价于linux终端命令 "ulimit -n 102400"
struct rlimit rt;
rt.rlim_max = rt.rlim_cur = FDSIZE;
if (setrlimit(RLIMIT_NOFILE, &rt) == -1)
{
perror("setrlimit error");
return -1;
}
return 0;
}
static void signal_exit_handler()
{
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
sa.sa_handler = signal_exit_func;
sigaction(SIGINT, &sa, NULL);//当按下ctrl+c时，它的效果就是发送SIGINT信号
sigaction(SIGTERM, &sa, NULL);//kill pid
sigaction(SIGQUIT, &sa, NULL);//ctrl+\代表退出SIGQUIT
//SIGSTOP和SIGKILL信号是不可捕获的,所以下面两句话写了等于没有写
sigaction(SIGKILL, &sa, NULL);//kill -9 pid
sigaction(SIGSTOP, &sa, NULL);//ctrl+z代表停止
//#define SIGTERM 15
//#define SIGKILL 9
//kill和kill -9，两个命令在linux中都有杀死进程的效果，然而两命令的执行过程却大有不同，在程序中如果用错了，可能会造成莫名其妙的现象。
//执行kill pid命令，系统会发送一个SIGTERM信号给对应的程序。
//执行kill -9 pid命令，系统给对应程序发送的信号是SIGKILL，即exit。exit信号不会被系统阻塞，所以kill -9能顺利杀掉进程。
}
static void signal_exit_func(int signo)
{
printf("exit signo is %d\n", signo);
stop_server = 1;
}
---
参考文章：
我个人的Linux TCP server和client测试源码，C语言（1）（★firecat推荐★）
IO多路复用之epoll总结 --- 注意源码有一处错误，需要修正为：
static void handle_accpet(int epollfd,int listenfd)
{
int clifd;
struct sockaddr_in cliaddr;
socklen_t cliaddrlen = sizeof(cliaddr);