#include "apue.h"#include <netdb.h>#include <errno.h>#include <syslog.h>#include <fcntl.h>#include <sys/socket.h>#include <sys/wait.h>#define QLEN 10#ifndef HOST_NAME_MAX#define HOST_NAME_MAX 256#endifextern int initserver(int, struct sockaddr *, socklen_t, int);voidserve(int sockfd){	int		clfd, status;	pid_t	pid;	for (;;) {		clfd = accept(sockfd, NULL, NULL);		if (clfd < 0) {			syslog(LOG_ERR, "ruptimed: accept error: %s",			  strerror(errno));			exit(1);		}		if ((pid = fork()) < 0) {			syslog(LOG_ERR, "ruptimed: fork error: %s",			  strerror(errno));			exit(1);		} else if (pid == 0) {	/* child */			/*			 * The parent called daemonize ({Prog daemoninit}), so			 * STDIN_FILENO, STDOUT_FILENO, and STDERR_FILENO			 * are already open to /dev/null.  Thus, the call to			 * close doesn't need to be protected by checks that			 * clfd isn't already equal to one of these values.			 */			if (dup2(clfd, STDOUT_FILENO) != STDOUT_FILENO ||			  dup2(clfd, STDERR_FILENO) != STDERR_FILENO) {				syslog(LOG_ERR, "ruptimed: unexpected error");				exit(1);			}			close(clfd);			execl("/usr/bin/uptime", "uptime", (char *)0);			syslog(LOG_ERR, "ruptimed: unexpected return from exec: %s",			  strerror(errno));		} else {		/* parent */			close(clfd);			waitpid(pid, &status, 0);		}	}}intmain(int argc, char *argv[]){	struct addrinfo	*ailist, *aip;	struct addrinfo	hint;	int				sockfd, err, n;	char			*host;	if (argc != 1)		err_quit("usage: ruptimed");#ifdef _SC_HOST_NAME_MAX	n = sysconf(_SC_HOST_NAME_MAX);	if (n < 0)	/* best guess */#endif		n = HOST_NAME_MAX;	host = malloc(n);	if (host == NULL)		err_sys("malloc error");	if (gethostname(host, n) < 0)		err_sys("gethostname error");	daemonize("ruptimed");	hint.ai_flags = AI_CANONNAME;	hint.ai_family = 0;	hint.ai_socktype = SOCK_STREAM;	hint.ai_protocol = 0;	hint.ai_addrlen = 0;	hint.ai_canonname = NULL;	hint.ai_addr = NULL;	hint.ai_next = NULL;	if ((err = getaddrinfo(host, "ruptime", &hint, &ailist)) != 0) {		syslog(LOG_ERR, "ruptimed: getaddrinfo error: %s",		  gai_strerror(err));		exit(1);	}	for (aip = ailist; aip != NULL; aip = aip->ai_next) {		if ((sockfd = initserver(SOCK_STREAM, aip->ai_addr,		  aip->ai_addrlen, QLEN)) >= 0) {			serve(sockfd);			exit(0);		}	}	exit(1);}