[root@localhost tcpip]# cat ./echo_mpserver.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <signal.h>
#define BUF_SIZE 1024
void error_handling(char *message);
void read_childproc(int sig);
int main(int argc, char *argv[]){
int serv_sock, clnt_sock;
struct sockaddr_in serv_addr, clnt_addr;
socklen_t addr_size;
int str_len, state;
struct sigaction act;
pid_t pid;
char message[BUF_SIZE];
if(argc!=2){
printf("Usage : %s <PORT> \n",argv[0]);
exit(1);
}
act.sa_handler=read_childproc;
sigemptyset(&act.sa_mask);
act.sa_flags=0;
state=sigaction(SIGCHLD, &act, 0);
serv_sock=socket(PF_INET, SOCK_STREAM, 0);
memset(&serv_addr, 0, sizeof(serv_addr));
serv_addr.sin_family=AF_INET;
serv_addr.sin_addr.s_addr=htonl(INADDR_ANY);
serv_addr.sin_port=htons(atoi(argv[1]));
if(bind(serv_sock, (struct sockaddr*)&serv_addr, sizeof(serv_addr))==-1){
error_handling("bind() error");
}
if(listen(serv_sock, 5)==-1){
error_handling("listen() error");
}
while(1)
{
addr_size=sizeof(clnt_addr);
clnt_sock=accept(serv_sock, (struct sockaddr*)&clnt_addr, &addr_size);
if(clnt_sock==-1){
continue;
}
else{
puts("New Client connected...\n");
}
pid=fork();
if(pid==-1){
close(clnt_sock);
continue;
}
if(pid==0){
close(serv_sock);
while((str_len=read(clnt_sock, message, BUF_SIZE))!=0)
{
write(clnt_sock, message, str_len);
}
close(clnt_sock);
return 0;
}
else{
close(clnt_sock);
}
}
close(serv_sock);
return 0;
}
void error_handling(char *message){
fputs(message, stderr);
fputc('\n', stderr);
exit(1);
}
void read_childproc(int sig){
pid_t pid;
int status;
pid=waitpid(-1, &status, WNOHANG);
printf("removed child process : %d \n", pid);
printf("child process send : %d \n", WEXITSTATUS(status));
}