unix网络编程 str_cli epoll 非阻塞版本
unix网络编程str_cli使用epoll实现讲了使用epoll配合阻塞io来实现str_cli,这个版本是配合非阻塞io.
可以看到采用非阻塞io以后复杂度大大提升了. 这个版本是在原书select版本基础之上修改而来,可以看出epoll又比select版本复杂了很多,每次都需要调用epoll_ctl三次,效率肯定比select还低.
存在一个问题!!就是epoll_wait对于重定向的stdin,始终阻塞,不晓得什么原因,以后再研究吧!
因为不能重定向stdin所以也不能测试性能,只能说是可以工作.
/* include nonb1 */
#include "../lib/unp.h"
#include <sys/epoll.h>
//epoll 非阻塞io， 采用了非阻塞io以后性能得到大幅提升，但是复杂度也飞速提升。
//确保events有足够的空间，这里足够了
//添加一个事件到队列中，可能会改变数组中的epoll_event数量。
static uint32_t addEvents(struct epoll_event * events,uint32_t nfds,int fd,uint32_t event){
int i=0;
for(i=0;i<nfds;i++){
if(events[i].data.fd==fd){
events[i].events|=event;
}
}
if(i==nfds){
events[i].data.fd=fd;
events[i].events=event;
nfds++;
}
return nfds;
}
#define VOL2
void str_cli(FILE *fp, int sockfd)
{
int val,stdineof=0;
ssize_t n, nwritten;
char to[MAXLINE], fr[MAXLINE];
char *toiptr, *tooptr, *friptr, *froptr;
struct epoll_event event;
struct epoll_event events[20];
int i,efd,nfds;
int noevent=0;
val = Fcntl(sockfd, F_GETFL, 0);
Fcntl(sockfd, F_SETFL, val | O_NONBLOCK);
val = Fcntl(STDIN_FILENO, F_GETFL, 0);
Fcntl(STDIN_FILENO, F_SETFL, val | O_NONBLOCK);
val = Fcntl(STDOUT_FILENO, F_GETFL, 0);
Fcntl(STDOUT_FILENO, F_SETFL, val | O_NONBLOCK);
toiptr = tooptr = to; /* initialize buffer pointers */
friptr = froptr = fr;
stdineof = 0;
efd = epoll_create (10);
if(efd<0){
err_sys("epoll create failed");
}
event.data.fd=fileno(fp);
event.events=EPOLLIN;
epoll_ctl(efd,EPOLL_CTL_ADD,fileno(fp),&event);
event.data.fd=sockfd;
event.events=EPOLLIN;
epoll_ctl(efd,EPOLL_CTL_ADD,sockfd,&event);
event.data.fd=STDOUT_FILENO;
event.events=EPOLLOUT;
epoll_ctl(efd,EPOLL_CTL_ADD,STDOUT_FILENO,&event);
for ( ; ; ) {
event.data.fd = fileno(fp);
event.events = 0;
//fprintf(stderr, "tooptr=0x%x,toiptr=0x%x,froptr=0x%x,friptr=0x%x
", tooptr, toiptr, froptr, friptr);
if (stdineof == 0 && toiptr < &to[MAXLINE]) //并不能确定在不在里面，多做一次不是坏事
{
event.events = EPOLLIN;
epoll_ctl(efd, EPOLL_CTL_MOD, fileno(fp), &event); //read from stdin
}
else
epoll_ctl(efd, EPOLL_CTL_MOD, fileno(fp), &event);
event.data.fd = sockfd;
event.events = 0;
if (friptr < &fr[MAXLINE])
event.events |= EPOLLIN; /* read from socket */
if (tooptr != toiptr)
event.events |= EPOLLOUT; /* data to write to socket */
epoll_ctl(efd, EPOLL_CTL_MOD, sockfd, &event);
event.data.fd = STDOUT_FILENO;
event.events = 0;
if (froptr != friptr) {
event.events = EPOLLOUT;
epoll_ctl(efd, EPOLL_CTL_MOD, STDOUT_FILENO, &event); /* data to write to stdout */
}
else {
epoll_ctl(efd, EPOLL_CTL_MOD, STDOUT_FILENO, &event);
}
nfds = epoll_wait(efd, events, sizeof(events) / sizeof(struct epoll_event), -1);
//fprintf(stderr, "nfds return:%d, %d,0x%x,sockfd=%d
", nfds, events[0].data.fd, events[0].events, sockfd);
startloop:
for (i = 0; i < nfds; i++) {
if (events[i].data.fd == STDIN_FILENO && events[i].events != 0) {
events[i].events = 0; //清除处理过的事件
if ((n = read(STDIN_FILENO, toiptr, &to[MAXLINE] - toiptr)) < 0) {
if (errno != EWOULDBLOCK)
err_sys("read error on stdin");
} else if (n == 0) {
#ifdef VOL2
fprintf(stderr, "%s: EOF on stdin
", gf_time());
#endif
stdineof = 1; /* all done with stdin */
if (tooptr == toiptr)
Shutdown(sockfd, SHUT_WR);/* send FIN */
} else {
#ifdef VOL2
fprintf(stderr, "%s: read %d bytes from stdin
", gf_time(), n);
#endif
toiptr += n; /* # just read */
int ret2=addEvents(events, nfds, sockfd, EPOLLOUT);
if(ret2!=nfds){
nfds=ret2;
goto startloop;
}
}
}
if (events[i].data.fd == sockfd && events[i].events != 0) {
if (events[i].events & EPOLLIN) {
printf("read socket
");
if ((n = read(sockfd, friptr, &fr[MAXLINE] - friptr)) < 0) {
printf("read socket error");
if (errno != EWOULDBLOCK)
err_sys("read error on socket");
} else if (n == 0) {
#ifdef VOL2
fprintf(stderr, "%s: EOF on socket
", gf_time());
#endif
if (stdineof)
return; /* normal termination */
else
err_quit("str_cli: server terminated prematurely");
} else {
#ifdef VOL2
fprintf(stderr, "%s: read %d bytes from socket
",
gf_time(), n);
#endif
friptr += n; /* # just read */
int ret2 = addEvents(events, nfds, STDOUT_FILENO, EPOLLOUT);/* try and write for next loop */
if(ret2!=nfds){
nfds=ret2;
events[i].events&=~EPOLLIN; //清除已经处理过的in事件
goto startloop;
}
}
}
if (events[i].events & EPOLLOUT) {
if ((n = toiptr - tooptr) > 0) {
if ((nwritten = write(sockfd, tooptr, n)) < 0) {
if (errno != EWOULDBLOCK)
err_sys("write error to socket");
} else {
#ifdef VOL2
fprintf(stderr, "%s: wrote %d bytes to socket
",
gf_time(), nwritten);
#endif
tooptr += nwritten; /* # just written */
if (tooptr == toiptr) {
toiptr = tooptr = to; /* back to beginning of buffer */
if (stdineof)
Shutdown(sockfd, SHUT_WR); /* send FIN */
}
}
}
}
events[i].events = 0; //清除处理过的事件
}
if (events[i].data.fd == STDOUT_FILENO) {
if ((n = friptr - froptr) > 0) {
if ((nwritten = write(STDOUT_FILENO, froptr, n)) < 0) {
if (errno != EWOULDBLOCK)
err_sys("write error to stdout");
} else {
#ifdef VOL2
fprintf(stderr, "%s: wrote %d bytes to stdout
",
gf_time(), nwritten);
#endif
froptr += nwritten; /* # just written */
if (froptr == friptr)
froptr = friptr = fr; /* back to beginning of buffer */
}
}
}
}
}
}