這是我前兩天所做的一個(gè)小練習(xí)，用epoll寫(xiě)個(gè)echo程序，里面用共享內(nèi)存存儲(chǔ)訪問(wèn)信息，貼在這里，哪天生疏了還可以過(guò)來(lái)查查~~ 更多內(nèi)容請(qǐng)?jiān)L問(wèn)：
http://lmlf001.blog.sohu.com/
//net_echo.cpp
//寫(xiě)一個(gè)程序，支持同時(shí)打開(kāi)10w個(gè)文件句柄，申請(qǐng)1G共享內(nèi)存，是一個(gè)tcp echo的server，采用select或epoll管理多連接
#include<sys/socket.h>
#include<sys/resource.h>
#include<stdio.h>
#include<sys/epoll.h>
#include<arpa/inet.h>
#include<strings.h>
#include<unistd.h>
#include<fcntl.h>
#include<errno.h>
#include<sys/shm.h>
#include<string.h>
#include<time.h>
#define SHM_MAX 1000000000UL //共享內(nèi)存大小
#define SHM_KEY 7896 //共享內(nèi)存申請(qǐng)時(shí)的key
#define SERV_PORT 4466 //服務(wù)端口號(hào)
#define MAX_RLIMIT 100000 //最大訪問(wèn)量
#define LISTENQ 5 //監(jiān)聽(tīng)隊(duì)列長(zhǎng)度
#define MAX_LINE 128 //緩存長(zhǎng)度
const char *local_addr="127.0.0.1";//綁定服務(wù)地址
struct access_info{ //記錄客戶(hù)訪問(wèn)信息
time_t a_time; //客戶(hù)訪問(wèn)時(shí)間
in_addr_t a_ip; //客戶(hù)ip
int a_errno; //是否訪問(wèn)成功，成功為0，否則為其錯(cuò)誤號(hào)
};
bool setnonblocking(int fd); //設(shè)置fd為非阻塞模式
bool set_fd_limit(unsigned int max); //設(shè)置系統(tǒng)允許的進(jìn)程所能打開(kāi)的文件描述符的最大值
int main(int argc,char **argv)
{
int listenfd=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);//建立serv socket
if(listenfd<0){
perror("create socket failed!");
return -1;
}
struct sockaddr_in servaddr,clientaddr;
bzero(&servaddr,sizeof(servaddr));
servaddr.sin_family=AF_INET;
servaddr.sin_port=htons(SERV_PORT);
inet_aton(local_addr,&(servaddr.sin_addr));
if(bind(listenfd,(sockaddr *)&servaddr,sizeof(servaddr))<0) //綁定本機(jī)地址
{
perror("bind error!");
return -1;
}
if(!set_fd_limit(MAX_RLIMIT)){
perror("setrlimit failed!");
return -1;
}
struct epoll_event ev,events[20];
int epfd=epoll_create(MAX_RLIMIT); //epoll_create
if(!setnonblocking(listenfd))return -1;
ev.data.fd=listenfd;
ev.events=EPOLLIN|EPOLLET;
epoll_ctl(epfd,EPOLL_CTL_ADD,listenfd,&ev);//把listenfd加入到epoll監(jiān)聽(tīng)隊(duì)列
int shm_id=shmget(SHM_KEY,SHM_MAX,IPC_CREAT|0600); //申請(qǐng)共享內(nèi)存
if(shm_id==-1){
perror("shmget");
return -2;
}
struct access_info client_info,*pos; //客戶(hù)信息
int *head;
head=(int *)shmat(shm_id,0,0);
if(int(head)==-1){
perror("shmat");
return -1;
}
*head=1; //服務(wù)器在運(yùn)行狀態(tài)，若該值變?yōu)?，則關(guān)閉服務(wù)器
if(*(head+1)!=1){ // head+1服務(wù)器是否第一次運(yùn)行，head+2共享內(nèi)存存儲(chǔ)的信息數(shù)量
*(head+1)=1; // ___________
*(head+2)=0; //head-->|___ 0/1___| 服務(wù)器的運(yùn)行狀態(tài)
} // |___ 0/1___| 共享內(nèi)存是否使用過(guò)，是為1，否則為0
// |___ n____| 共享內(nèi)存存儲(chǔ)信息數(shù)量 0~SHM_MAX/(3*4*8)-1
pos=(struct access_info *)(head)+1+*(head+2); //記錄信息的開(kāi)始位置
listen(listenfd,LISTENQ); //監(jiān)聽(tīng)客戶(hù)端請(qǐng)求
int nfds,i,connfd,sockfd,n;
socklen_t len;
char line[MAX_LINE];
while(*head)
{
nfds=epoll_wait(epfd,events,20,500); //檢測(cè)活躍連接
for(i=0;i<nfds;i++)
{
if(events[i].data.fd==listenfd) //有新連接到來(lái)
{
len=sizeof(clientaddr);
connfd=accept(listenfd,(sockaddr *)&clientaddr,&len);
client_info.a_time=time(NULL); //注冊(cè)客戶(hù)信息
client_info.a_ip=clientaddr.sin_addr.s_addr;
client_info.a_errno=0;
if(connfd<0){
perror("connfd<0!");
client_info.a_errno=errno;
continue;
}
memcpy(pos,&client_info,sizeof(client_info));
pos++; //共享內(nèi)存指針后移，并把信息數(shù)量加1
if((*(head+2))++>4*SHM_MAX/(3*8*4*5)) //共享內(nèi)存剩余不足1/5時(shí)發(fā)出警告信息
fprintf(stderr,"Warning:share memory is being not enough
\n Left:%d\n",SHM_MAX-*(head+2)*3*4*8);
if(!setnonblocking(connfd))continue;
ev.data.fd=connfd;
ev.events=EPOLLIN|EPOLLET;
epoll_ctl(epfd,EPOLL_CTL_ADD,connfd,&ev);//新連接加入epoll_wait
}
else if(events[i].events&EPOLLIN) //連接可讀
{
if((sockfd=events[i].data.fd)<0)continue;
while((n=read(sockfd,line,MAX_LINE))==MAX_LINE)
write(sockfd,line,n);
if(n<0)
{
if (errno == ECONNRESET) {
events[i].data.fd = -1;
epoll_ctl(epfd,EPOLL_CTL_DEL,sockfd,NULL);
close(sockfd);
continue;
}
else continue; //恰好讀完MAX_LINE后無(wú)數(shù)據(jù)
}
else if(n==0){ //客戶(hù)端關(guān)閉連接
epoll_ctl(epfd,EPOLL_CTL_DEL,sockfd,NULL);
close(sockfd);
events[i].data.fd = -1;
continue;
}
else write(sockfd,line,n);
}
/* else if(events[i].events&EPOLLOUT)
{
sockfd=events[i].data.fd;
if(sockfd<0)continue;
write(sockfd,line,n);
ev.data.fd=sockfd;
ev.events=EPOLLIN|EPOLLET;
epoll_ctl(epfd,EPOLL_CTL_MOD,sockfd,&ev);
}
*/ }
}
shmdt(head); //卸載共享內(nèi)存
close(epfd);
close(listenfd);
return 0;
}
bool setnonblocking(int sock)
{
int opts;
opts=fcntl(sock,F_GETFL);
if(opts<0)
{
perror("fcntl(sock,GETFL)");
return false;
}
opts = opts|O_NONBLOCK;
if(fcntl(sock,F_SETFL,opts)<0)
{
perror("fcntl(sock,SETFL,opts)");
return false;
}
return true;
}
bool set_fd_limit(unsigned int max)
{
struct rlimit rlim,rlim_new;
if (getrlimit(RLIMIT_NOFILE, &rlim)!=0)
return false;
if(rlim.rlim_cur>=max) return true;
if(rlim.rlim_max==RLIM_INFINITY||rlim.rlim_max>=max){
rlim_new.rlim_max = rlim.rlim_max;
rlim_new.rlim_cur = max;
}
else{
if(geteuid()!=0){errno=1;return false; }
rlim_new.rlim_max=rlim_new.rlim_cur=max;
}
if (setrlimit(RLIMIT_NOFILE, &rlim_new)!=0) {/* failed. try raising just to the old max */
int err=errno;
setrlimit(RLIMIT_NOFILE, &rlim);
errno=err;
return false;
}
return true;
}/*----------------------------------------------------------------*/
//net_echo_shutdown.cpp
//啟動(dòng)該進(jìn)程時(shí)，關(guān)閉net_echo服務(wù)進(jìn)程
#include<sys/shm.h>
#include<stdio.h>
#include<unistd.h>
#include<errno.h>
#define SHM_MAX 1000000000UL //共享內(nèi)存大小
#define SHM_KEY 7896 //共享內(nèi)存申請(qǐng)時(shí)的key
#ifndef IPC_ALLOC
#define IPC_ALLOC IPC_CREAT
#endif
int main(int argc,char **argv)
{
if(geteuid()!=0){
errno=1;
perror("net_echo_shutdown:");
return -1;
}
int shmid;
if((shmid=shmget(SHM_KEY,SHM_MAX,IPC_ALLOC|0600))==-1)
{
perror("shmget()");
return -1;
}
int *head=(int *)shmat(shmid,0,0);
if(int(head)==-1){
perror("shmat()");
return -1;
}
if(*head!=1){ //服務(wù)器并未運(yùn)行
fprintf(stderr,"Net_echo server is not running\n");
return -1;
}
*head=0; //設(shè)置關(guān)閉標(biāo)志
printf("Shutdown the echo server\n");
sleep(2);
shmdt(head);
return 0;
}
/******************************************************************/
//print_shm.cpp
//讀取并打印共享內(nèi)存信息
#include<stdio.h>
#include<sys/shm.h>
#include<unistd.h>
#include<errno.h>
#include<time.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#include<string.h>
#define SHM_KEY 7896
#define SHM_MAX 1000000000UL
#ifndef IPC_ALLOC
#define IPC_ALLOC IPC_CREAT
#endif
struct access_info{ //記錄客戶(hù)訪問(wèn)信息
time_t a_time; //客戶(hù)訪問(wèn)時(shí)間
in_addr_t a_ip; //客戶(hù)ip
int a_errno; //是否訪問(wèn)成功，成功為0，否則為其錯(cuò)誤號(hào)
};
int main(int argc,char **argv)
{
if(geteuid()!=0){
errno=1;
perror("print_shm:");
return -1;
}
int shmid=shmget(SHM_KEY,SHM_MAX,IPC_ALLOC|0600);
if(shmid==-1)
{
perror("shmget()");
return -1;
}
int *head=(int *)shmat(shmid,0,0);
if(int(head)==-1){
perror("shmat()");
return -1;
}
if(*(head+1)!=1){
fprintf(stderr,"SHM have not be used!\n");
return -1;
}
struct access_info *pos=(access_info *)(head)+1;
for(int i=0;i<*(head+2);i++,pos++)
printf("%-15s%-10s%20s%s",inet_ntoa(*(in_addr *)&(pos->a_ip)),pos->a_errno==0?"Success!":"Failed:",
pos->a_errno==0?"":strerror(pos->a_errno),ctime(&pos->a_time));
shmdt(head);
return 0;
}