多路复用I/O模型epoll() 模型 代码实现

  1 #include <netinet/in.h>
  2 #include <sys/socket.h>
  3 #include <stdio.h>
  4 #include <string.h>
  5 #include <stdlib.h>
  6 #include <sys/epoll.h>
  7 #include <time.h>
  8 #include <unistd.h>
  9 #include <sys/types.h>
 10 #include <arpa/inet.h>
 11 
 12 #define MAXSIZE     1024
 13 #define IPADDRESS   "127.0.0.1"
 14 #define SERV_PORT   8787
 15 #define FDSIZE        1024
 16 #define EPOLLEVENTS 20
 17 
 18 static void handle_connection(int sockfd);
 19 static void
 20 handle_events(int epollfd,struct epoll_event *events,int num,int sockfd,char *buf);
 21 static void do_read(int epollfd,int fd,int sockfd,char *buf);
 22 static void do_read(int epollfd,int fd,int sockfd,char *buf);
 23 static void do_write(int epollfd,int fd,int sockfd,char *buf);
 24 static void add_event(int epollfd,int fd,int state);
 25 static void delete_event(int epollfd,int fd,int state);
 26 static void modify_event(int epollfd,int fd,int state);
 27 
 28 int main(int argc,char *argv[])
 29 {
 30     int                 sockfd;
 31     struct sockaddr_in  servaddr;
 32     sockfd = socket(AF_INET,SOCK_STREAM,0);
 33     bzero(&servaddr,sizeof(servaddr));
 34     servaddr.sin_family = AF_INET;
 35     servaddr.sin_port = htons(SERV_PORT);
 36     inet_pton(AF_INET,IPADDRESS,&servaddr.sin_addr);
 37     connect(sockfd,(struct sockaddr*)&servaddr,sizeof(servaddr));
 38     //处理连接
 39     handle_connection(sockfd);
 40     close(sockfd);
 41     return 0;
 42 }
 43 
 44 
 45 static void handle_connection(int sockfd)
 46 {
 47     int epollfd;
 48     struct epoll_event events[EPOLLEVENTS];
 49     char buf[MAXSIZE];
 50     int ret;
 51     epollfd = epoll_create(FDSIZE);
 52     add_event(epollfd,STDIN_FILENO,EPOLLIN);
 53     for ( ; ; )
 54     {
 55         ret = epoll_wait(epollfd,events,EPOLLEVENTS,-1);
 56         handle_events(epollfd,events,ret,sockfd,buf);
 57     }
 58     close(epollfd);
 59 }
 60 
 61 static void
 62 handle_events(int epollfd,struct epoll_event *events,int num,int sockfd,char *buf)
 63 {
 64     int fd;
 65     int i;
 66     for (i = 0;i < num;i++)
 67     {
 68         fd = events[i].data.fd;
 69         if (events[i].events & EPOLLIN)
 70             do_read(epollfd,fd,sockfd,buf);
 71         else if (events[i].events & EPOLLOUT)
 72             do_write(epollfd,fd,sockfd,buf);
 73     }
 74 }
 75 
 76 static void do_read(int epollfd,int fd,int sockfd,char *buf)
 77 {
 78     int nread;
 79     nread = read(fd,buf,MAXSIZE);
 80         if (nread == -1)
 81     {
 82         perror("read error:");
 83         close(fd);
 84     }
 85     else if (nread == 0)
 86     {
 87         fprintf(stderr,"server close.\n");
 88         close(fd);
 89     }
 90     else
 91     {
 92         if (fd == STDIN_FILENO)
 93             add_event(epollfd,sockfd,EPOLLOUT);
 94         else
 95         {
 96             delete_event(epollfd,sockfd,EPOLLIN);
 97             add_event(epollfd,STDOUT_FILENO,EPOLLOUT);
 98         }
 99     }
100 }
101 
102 static void do_write(int epollfd,int fd,int sockfd,char *buf)
103 {
104     int nwrite;
105     nwrite = write(fd,buf,strlen(buf));
106     if (nwrite == -1)
107     {
108         perror("write error:");
109         close(fd);
110     }
111     else
112     {
113         if (fd == STDOUT_FILENO)
114             delete_event(epollfd,fd,EPOLLOUT);
115         else
116             modify_event(epollfd,fd,EPOLLIN);
117     }
118     memset(buf,0,MAXSIZE);
119 }
120 
121 static void add_event(int epollfd,int fd,int state)
122 {
123     struct epoll_event ev;
124     ev.events = state;
125     ev.data.fd = fd;
126     epoll_ctl(epollfd,EPOLL_CTL_ADD,fd,&ev);
127 }
128 
129 static void delete_event(int epollfd,int fd,int state)
130 {
131     struct epoll_event ev;
132     ev.events = state;
133     ev.data.fd = fd;
134     epoll_ctl(epollfd,EPOLL_CTL_DEL,fd,&ev);
135 }
136 
137 static void modify_event(int epollfd,int fd,int state)
138 {
139     struct epoll_event ev;
140     ev.events = state;
141     ev.data.fd = fd;
142     epoll_ctl(epollfd,EPOLL_CTL_MOD,fd,&ev);
143 }