TCP并发服务器(一)——每个客户一个子进程

#include "unp.h"

int main(int argc, char *argv[])
{
int listenfd;
socklen_t addrlen;
if (argc = 2) {
listenfd = Tcp_listen(NULL, argv[1], &addrlen);
} else if (argc ==3) {
listenfd = Tcp_listen(argv[1], argv[2], &addrlen);
} else {
err_quit("Usage: a.out [ <host> ] <port#>");
}
struct sockaddr *cliaddr = (struct sockaddr*)Malloc(addrlen);

void sig_chld(int), sig_int(int), web_child(int);
Signal(SIGCHLD, sig_chld);
Signal(SIGINT, sig_int);

for ( ; ;) {
socklen_t clilen = addrlen;
DPRINTF("Wait for a connection\n");
int connfd = accept(listenfd, cliaddr, &clilen);    //clilen用于值-结果参数，可能会改变，所以每次重新赋值，所以此处不能使用addrlen
DPRINTF("Accept a connection\n");
if (connfd < 0) {
if (errno == EINTR) {
continue;
} else {
err_sys("accept() error");
}
}

pid_t childpid = Fork();
if (childpid == 0) {        //child process
DPRINTF("Fork a child process\n");
Close(listenfd);        //close listening socket
web_child(connfd);        //process request
exit(0);
}
Close(connfd);                //parent closes connected socket
} //end for(;;)

return 0;
}

void sig_int(int)
{
DPRINTF("sig_int()\n");
void pr_cpu_time(void);
pr_cpu_time();
exit(0);
}

void sig_chld(int)
{
static int cnt = 0;
pid_t pid;
int stat;
//param1: 想要等待的PID；-1: 等待第一个终止的子进程
//param2: 子进程的终止状态(整数)
//param3: 附加选项；WNOHANG：没有子进程终止时，不阻塞
while ((pid = waitpid(-1, &stat, WNOHANG)) > 0) {    //成功：返回进程ID > 0, 出错：0或-1
DPRINTF("Waitpid for %d child process\n", ++cnt);
;
}

return;
}