epoll默认情况下是水平触发模式，这次将epoll设置为边缘触发模式来实现服务器，而客户端直接使用完美回声服务器的客户端。
服务器代码
#include
#include
#include
#include
#include
#include
#include
#include
#include
const int BUF_SIZE = 4;
const int EPOLL_SIZE = 50;
void setnonblockingmode(int fd);
void error_handling(const char *buf);
int main(int argc, char *argv[]) {
int server_sock, client_sock;
sockaddr_in server_addr, client_addr;
socklen_t addr_size;
ssize_t str_len;
int i;
char buf[BUF_SIZE];
epoll_event *ep_events;
epoll_event event;
int epfd, event_cnt;
if (argc != 2) {
printf("Usage : %s \n", argv[0]);
exit(1);
}
server_sock = socket(PF_INET, SOCK_STREAM, 0);
memset(&server_addr, 0, sizeof(server_addr));
server_addr.sin_family = AF_INET;
server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
server_addr.sin_port = htons(atoi(argv[1]));
if (bind(server_sock, (sockaddr*)&server_addr, sizeof(server_addr)) == -1) {
error_handling("bind() error");
exit(1);
}
if (listen(server_sock, 5) == -1) {
error_handling("listen() error");
}
epfd = epoll_create(EPOLL_SIZE);
ep_events = (epoll_event*)malloc(sizeof(epoll_event) * EPOLL_SIZE);
event.events = EPOLLIN;
event.data.fd = server_sock;
epoll_ctl(epfd, EPOLL_CTL_ADD, server_sock, &event);
while (1) {
event_cnt = epoll_wait(epfd, ep_events, EPOLL_SIZE, -1);
if (event_cnt == -1) {
puts("epoll_wait() error");
break;
}
for (int i = 0; i < event_cnt; ++i) {
if (ep_events[i].data.fd == server_sock) {
addr_size = sizeof(client_addr);
client_sock = accept(server_sock, (sockaddr*)&client_addr, &addr_size);
setnonblockingmode(client_sock); // 设置client socket为非阻塞模式
event.events = EPOLLIN | EPOLLET; // 设置epoll边缘触发
event.data.fd = client_sock;
epoll_ctl(epfd, EPOLL_CTL_ADD, client_sock, &event);
printf("connect client: %d\n", client_sock);
} else {
while (1) { // 将数据读完为止
str_len = read(ep_events[i].data.fd, buf, BUF_SIZE);
if (str_len == 0) {
epoll_ctl(epfd, EPOLL_CTL_DEL, ep_events[i].data.fd, NULL);
close(ep_events[i].data.fd);
printf("closed client: %d\n", ep_events[i].data.fd);
} else if (str_len < 0) {
if (errno == EAGAIN) { // 已无数据
break;
}
}
else {
write(ep_events[i].data.fd, buf,str_len);
}
}
}
}
}
close(server_sock);
close(epfd);
return 0;
}
// 将文件描述符设置为非阻塞
void setnonblockingmode(int fd) {
int flag = fcntl(fd, F_GETFL, 0);
fcntl(fd, F_SETFL, flag | O_NONBLOCK);
}
项目代码
参考
