1.实现一个多进程的并发服务器

#include<stdio.h>
#include<unistd.h>
#include<stdlib.h>
#include<arpa/inet.h>
#include<strings.h>
#include<ctype.h>
#include<sys/socket.h>
#include<sys/types.h>
#include<signal.h>
#include<sys/wait.h>#define SERV_IP "192.168.0.2"
#define SERV_PORT 8888void wait_child(int signo)
{while(waitpid(0,NULL,WNOHANG)>0);return;
}int main()
{pid_t pid;int lfd,cfd;struct sockaddr_in serv_addr,clie_addr;socklen_t clie_addr_len;char buf[BUFSIZ],clie_IP[BUFSIZ];int n,i,ret;lfd = socket(AF_INET,SOCK_STREAM,0);if(lfd==-1){perror("socket error");exit(1);}bzero(&serv_addr,sizeof(serv_addr));serv_addr.sin_family = AF_INET;serv_addr.sin_port = htons(SERV_PORT);//inet_pton(AF_INET,SERV_IP,&serv_addr.sin_addr.s_addr);serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);ret = bind(lfd,(struct sockaddr *)&serv_addr,sizeof(serv_addr));if(ret==-1){perror("bind error");exit(1);}  ret = listen(lfd,128);if(ret==-1){perror("listen error");exit(1);}while(1){clie_addr_len = sizeof(clie_addr);cfd = accept(lfd,(struct sockaddr *)&clie_addr,&clie_addr_len);if(cfd==-1){perror("accept error");exit(1);}printf("client IP:%s,port:%d\n",inet_ntop(AF_INET,&clie_addr.sin_addr.s_addr,clie_IP,sizeof(clie_IP)),ntohs(clie_addr.sin_port));pid = fork();if(pid<0){perror("fork error");exit(1);}else if(pid == 0){close(lfd);while(1){n = read(cfd,buf,sizeof(buf));if(n==0){close(cfd);return 0;}else if(n==-1){perror("read error");exit(1);}else{for(i=0;i<n;i++){buf[i] = toupper(buf[i]);}write(cfd,buf,n);}}}else{close(cfd);signal(SIGCHLD,wait_child);}}return 0;
}