网络服务器处理阻塞问题
最近客户采用采用多个进程来同时对snmp服务器来set/get ，有时候会造成网络服务器 net-snmp 的阻塞而无服务器反馈信息
为了改善，自己写了一个简单服务器，为了提高处理效果，创建子进程来处理，并由父进程来回收
代码如下：
头文件：
socket_include.h
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/socket.h> #include <netinet/in.h>
server.c
#include <time.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <termios.h>
#include <string.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/shm.h>
#include "socket_include.h"
#define MAXLINE 80
#define SERV_PORT 1234
struct serialdata{
int cur[10][24];
int mincur[10][24];
int maxcur[10][24];
int minTcur[10][3];
int maxTcur[10][3];
int minTvol[10][3];
int maxTvol[10][3];
int minTH[10][8];
int maxTH[10][8];
int Tcur[10][3];
int Tvol[10][3];
int temp[10][4];
int hum[10][4];
int water[10];
int smoke[10];
int door[10][2];
int kwh[10][24];
int Tpowerfactor[10][3];
int Tkwh[10][3];
int swicth[10][24];
int outputnum[10];
int online[10];
int type[10];
int m_s;
int alramflag[10][24+3+3+9];//output cur vol th
////////////////////////////////////////////////
int numperswicth[6];
int ondelaytime;
int offdelaytime;
char slavename[10][32];
char outputname[10][24][32];
};
struct serialdata *memdata;
struct serialdata *shmdata()
{
key_t shmkey;
int shmid;
shmkey=ftok("/",'b');
shmid=shmget(shmkey,sizeof(struct serialdata)*2,0666|IPC_CREAT);
if(shmid==-1)
return NULL;
struct serialdata * addr;
addr=(struct serialdata*)shmat(shmid,0,0);
if(addr==(struct serialdata*)-1)
return NULL;
return addr;
}
void handler(int num) {
//我接受到了SIGCHLD的信号啦
int status;
int pid = waitpid(-1, &status, WNOHANG);
if (WIFEXITED(status)) {
printf("The child %d exit with code %d\n", pid, WEXITSTATUS(status));
}
}
int main()
{
memdata = NULL;
memdata = shmdata();
if(memdata==NULL)
{
return -1;
}
//网络服务
pid_t pid;
struct sockaddr_in servaddr, cliaddr;
socklen_t cliaddr_len;
int listenfd, connfd;
char buf[MAXLINE];
char str[INET_ADDRSTRLEN];
int i, n;
int index=0;
int outindex=0;
char cmd1[256];
char show[255];
listenfd = socket(AF_INET, SOCK_STREAM, 0);
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port = htons(SERV_PORT);
bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr));
listen(listenfd, 20);
printf("Accepting connections ...\n");
while (1) {
cliaddr_len = sizeof(cliaddr);
connfd = accept(listenfd,
(struct sockaddr *)&cliaddr, &cliaddr_len);
n = read(connfd, buf, MAXLINE);//读取网络数据
buf[n]='\0';
printf("received from %s at PORT %d,buf:%s\n",
inet_ntop(AF_INET, &cliaddr.sin_addr, str, sizeof(str)),
ntohs(cliaddr.sin_port),buf);
signal(SIGCHLD, handler);
pid=fork();
if(pid<0)
{
perror("fork error");
}
else if(pid==0)//子进程处理数据
{
for(index=0;index<10;index++)
{
for(outindex=0;outindex<24;outindex++)
{
memset(cmd1,0,sizeof(char)*255);
sprintf(cmd1,"OFF %d %d",index,outindex+1);
if(strcmp(cmd1,buf)==0)
{
printf("is in readcmd succed!\n");
char sworder[255];
//关输出位
for(n=0;n<2;n++)
{
memdata->swicth[index][outindex]=1;
memset(sworder,0,sizeof(char)*255);
printf("\n");
sprintf(sworder,"/clever/bin/order %d %d 2 1",index,outindex+1);
system(sworder);
printf("the off order is dnoe.\n");
printf("\n");
}
break;
}
memset(cmd1,0,sizeof(char)*255);
sprintf(cmd1,"ON %d %d",index,outindex+1);
if(strcmp(cmd1,buf)==0)
{
printf("is in readcmd succed!\n");
//关输出位
char sworder[255];
for(n=0;n<2;n++)
{
memdata->swicth[index][outindex]=2;
memset(sworder,0,sizeof(char)*255);
printf("\n");
sprintf(sworder,"/clever/bin/order %d %d 1 1",index,outindex+1);
system(sworder);
printf("the on order is dnoe.\n");
printf("\n");
}
break;
}
memset(cmd1,0,sizeof(char)*255);
sprintf(cmd1,"status %d %d",index,outindex+1);
if(strcmp(cmd1,buf)==0)
{
memset(show,0,sizeof(char)*255);
sprintf(show,"status:%s\n",memdata->swicth[index][outindex]==0?"--":
(memdata->swicth[index][outindex]==1?"OFF":"ON"));
write(connfd, show, strlen(show));
break;
}
}
}
//处理完成
write(connfd, "exit sucessed!\n", strlen("exit sucessed!\n"));
close(connfd);//短连接结束
exit(0);
}
/*
for (i = 0; i < n; i++)
buf[i] = toupper(buf[i]);
write(connfd, buf, n);
*/
//write(connfd, "exit sucessed!\n", strlen("exit sucessed!\n"));
// close(connfd);
}
return 0;
}
客户端：
#include "socket_include.h"
#define MAXLINE 80
#define SERV_PORT 1234
int main(int argc, char *argv[])
{
struct sockaddr_in servaddr;
char buf[MAXLINE];
int sockfd, n;
char *str;
if (argc != 2) {
fputs("usage: ./client message\n", stderr);
exit(1);
}
str = argv[1];
sockfd = socket(AF_INET, SOCK_STREAM, 0);
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
//inet_pton(AF_INET, "127.0.0.1", &servaddr.sin_addr);
inet_pton(AF_INET, "192.168.1.239", &servaddr.sin_addr);
servaddr.sin_port = htons(SERV_PORT);
connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr));
write(sockfd, str, strlen(str));
n = read(sockfd, buf, MAXLINE);
buf[n]='\0';
printf("Response from server:%s\n",buf);
//write(STDOUT_FILENO, buf, n);
close(sockfd);
return 0;
}
测试程序：
#include <stdio.h>
int main()
{
int i=0;
for(i=0;i<100;i++)
{
printf("./client 'ON 0 9'\n");
system("./client 'ON 0 9'");
sleep(1);
system("./client 'status 0 9'");
sleep(1);
printf("./client 'OFF 0 9'\n");
system("./client 'OFF 0 9'");
sleep(1);
system("./client 'status 0 9'");
sleep(1);
}
return 0;
}
