timed.c

早期freebsd实现

#ifdef sgi
	(void)_daemonize(debug ? _DF_NOFORK|_DF_NOCHDIR : 0, sock, -1, -1);
#else
	if (!debug)
		daemon(debug, 0);
#endif /* sgi */

	if (trace)
		traceon();
	openlog("timed", LOG_CONS|LOG_PID, LOG_DAEMON);

	/*
	 * keep returning here
	 */
	ret = setjmp(jmpenv);
	savefromnet = fromnet;
	setstatus();

	if (Mflag) {
		switch (ret) {

		case 0:
			checkignorednets();
			pickslavenet(0);
			break;
		case 1:
			/* Just lost our master */
			if (slavenet != 0)
				slavenet->status = election(slavenet);
			if (!slavenet || slavenet->status == MASTER) {
				checkignorednets();
				pickslavenet(0);
			} else {
				makeslave(slavenet);	/* prune extras */
			}
			break;

		case 2:
			/* Just been told to quit */
			justquit = 1;
			pickslavenet(savefromnet);
			break;
		}

		setstatus();
		if (!(status & MASTER) && sock_raw != -1) {
			/* sock_raw is not being used now */
			(void)close(sock_raw);
			sock_raw = -1;
		}

		if (status == MASTER)
			master();
		else
			slave();

	} else {
		if (sock_raw != -1) {
			(void)close(sock_raw);
			sock_raw = -1;
		}

		if (ret) {
			/* we just lost our master or were told to quit */
			justquit = 1;
		}
		for (ntp = nettab; ntp != NULL; ntp = ntp->next) {
			if (ntp->status == MASTER)
				rmnetmachs(ntp);
				ntp->status = NOMASTER;
		}
		checkignorednets();
		pickslavenet(0);
		setstatus();

		slave();
	}
	/* NOTREACHED */
#ifdef lint
	return(0);
#endif
}

/*
 * suppress an upstart, untrustworthy, self-appointed master
 */
void
suppress(addr, name,net)
	struct sockaddr_in *addr;
	char *name;
	struct netinfo *net;
{
	struct sockaddr_in tgt;
	char tname[MAXHOSTNAMELEN];
	struct tsp msg;
	static struct timeval wait;

	if (trace)
		fprintf(fd, "suppress: %s\n", name);
	tgt = *addr;
	(void)strcpy(tname, name);

	while (0 != readmsg(TSP_ANY, ANYADDR, &wait, net)) {
		if (trace)
			fprintf(fd, "suppress:\tdiscarded packet from %s\n",
				    name);
	}

	syslog(LOG_NOTICE, "suppressing false master %s", tname);
	msg.tsp_type = TSP_QUIT;
	(void)strcpy(msg.tsp_name, hostname);
	(void)acksend(&msg, &tgt, tname, TSP_ACK, 0, 1);
}

void
lookformaster(ntp)
	struct netinfo *ntp;
{
	struct tsp resp, conflict, *answer;
	struct timeval ntime;
	char mastername[MAXHOSTNAMELEN];
	struct sockaddr_in masteraddr;

	get_goodgroup(0);
	ntp->status = SLAVE;

	/* look for master */
	resp.tsp_type = TSP_MASTERREQ;
	(void)strcpy(resp.tsp_name, hostname);
	answer = acksend(&resp, &ntp->dest_addr, ANYADDR,
			 TSP_MASTERACK, ntp, 0);
	if (answer != 0 && !good_host_name(answer->tsp_name)) {
		suppress(&from, answer->tsp_name, ntp);
		ntp->status = NOMASTER;
		answer = 0;
	}
	if (answer == 0) {
		/*
		 * Various conditions can cause conflict: races between
		 * two just started timedaemons when no master is
		 * present, or timedaemons started during an election.
		 * A conservative approach is taken.  Give up and became a
		 * slave, postponing election of a master until first
		 * timer expires.
		 */
		ntime.tv_sec = ntime.tv_usec = 0;
		answer = readmsg(TSP_MASTERREQ, ANYADDR, &ntime, ntp);
		if (answer != 0) {
			if (!good_host_name(answer->tsp_name)) {
				suppress(&from, answer->tsp_name, ntp);
				ntp->status = NOMASTER;
			}
			return;
		}

		ntime.tv_sec = ntime.tv_usec = 0;
		answer = readmsg(TSP_MASTERUP, ANYADDR, &ntime, ntp);
		if (answer != 0) {
			if (!good_host_name(answer->tsp_name)) {
				suppress(&from, answer->tsp_name, ntp);
				ntp->status = NOMASTER;
			}
			return;
		}

		ntime.tv_sec = ntime.tv_usec = 0;
		answer = readmsg(TSP_ELECTION, ANYADDR, &ntime, ntp);
		if (answer != 0) {
			if (!good_host_name(answer->tsp_name)) {
				suppress(&from, answer->tsp_name, ntp);
				ntp->status = NOMASTER;
			}
			return;
		}

		if (Mflag)
			ntp->status = MASTER;
		else
			ntp->status = NOMASTER;
		return;
	}

	ntp->status = SLAVE;
	(void)strcpy(mastername, answer->tsp_name);
	masteraddr = from;

	/*
	 * If network has been partitioned, there might be other
	 * masters; tell the one we have just acknowledged that
	 * it has to gain control over the others.
	 */
	ntime.tv_sec = 0;
	ntime.tv_usec = 300000;
	answer = readmsg(TSP_MASTERACK, ANYADDR, &ntime, ntp);
	/*
	 * checking also not to send CONFLICT to ack'ed master
	 * due to duplicated MASTERACKs
	 */
	if (answer != NULL &&
	    strcmp(answer->tsp_name, mastername) != 0) {
		conflict.tsp_type = TSP_CONFLICT;
		(void)strcpy(conflict.tsp_name, hostname);
		if (!acksend(&conflict, &masteraddr, mastername,
			     TSP_ACK, 0, 0)) {
			syslog(LOG_ERR,
			       "error on sending TSP_CONFLICT");
		}
	}
}

/*
 * based on the current network configuration, set the status, and count
 * networks;
 */
void
setstatus()
{
	struct netinfo *ntp;

	status = 0;
	nmasternets = nslavenets = nnets = nignorednets = 0;
	if (trace)
		fprintf(fd, "Net status:\n");
	for (ntp = nettab; ntp != NULL; ntp = ntp->next) {
		switch ((int)ntp->status) {
		case MASTER:
			nmasternets++;
			break;
		case SLAVE:
			nslavenets++;
			break;
		case NOMASTER:
		case IGNORE:
			nignorednets++;
			break;
		}
		if (trace) {
			fprintf(fd, "\t%-16s", inet_ntoa(ntp->net));
			switch ((int)ntp->status) {
			case NOMASTER:
				fprintf(fd, "NOMASTER\n");
				break;
			case MASTER:
				fprintf(fd, "MASTER\n");
				break;
			case SLAVE:
				fprintf(fd, "SLAVE\n");
				break;
			case IGNORE:
				fprintf(fd, "IGNORE\n");
				break;
			default:
				fprintf(fd, "invalid state %d\n",
					(int)ntp->status);
				break;
			}
		}
		nnets++;
		status |= ntp->status;
	}
	status &= ~IGNORE;
	if (trace)
		fprintf(fd,
			"\tnets=%d masters=%d slaves=%d ignored=%d delay2=%d\n",
			nnets, nmasternets, nslavenets, nignorednets, delay2);
}

void
makeslave(net)
	struct netinfo *net;
{
	register struct netinfo *ntp;

	for (ntp = nettab; ntp != NULL; ntp = ntp->next) {
		if (ntp->status == SLAVE && ntp != net)
			ntp->status = IGNORE;
	}
	slavenet = net;
}

/*
 * Try to become master over ignored nets..
 */
static void
checkignorednets()
{
	register struct netinfo *ntp;

	for (ntp = nettab; ntp != NULL; ntp = ntp->next) {
		if (!Mflag && ntp->status == SLAVE)
			break;

		if (ntp->status == IGNORE || ntp->status == NOMASTER) {
			lookformaster(ntp);
			if (!Mflag && ntp->status == SLAVE)
				break;
		}
	}
}

/*
 * choose a good network on which to be a slave
 *	The ignored networks must have already been checked.
 *	Take a hint about for a good network.
 */
static void
pickslavenet(ntp)
	struct netinfo *ntp;
{
	if (slavenet != 0 && slavenet->status == SLAVE) {
		makeslave(slavenet);		/* prune extras */
		return;
	}

	if (ntp == 0 || ntp->status != SLAVE) {
		for (ntp = nettab; ntp != 0; ntp = ntp->next) {
			if (ntp->status == SLAVE)
				break;
		}
	}
	makeslave(ntp);
}

/*
 * returns a random number in the range [inf, sup]
 */
long
casual(inf, sup)
	long inf, sup;
{
	double value;

	value = ((double)(random() & 0x7fffffff)) / (0x7fffffff*1.0);
	return(inf + (sup - inf)*value);
}

char *
date()
{
#ifdef sgi
	struct	timeval tv;
	static char tm[32];

	(void)gettimeofday(&tv, (struct timezone *)0);
	(void)cftime(tm, "%D %T", &tv.tv_sec);
	return (tm);
#else
	struct	timeval tv;

	(void)gettimeofday(&tv, (struct timezone *)0);
	return (ctime(&tv.tv_sec));
#endif /* sgi */
}

void
addnetname(name)
	char *name;
{
	register struct nets **netlist = &nets;

	while (*netlist)
		netlist = &((*netlist)->next);
	*netlist = (struct nets *)malloc(sizeof **netlist);
	if (*netlist == 0) {
		fprintf(stderr,"malloc failed\n");
		exit(1);
	}
	bzero((char *)*netlist, sizeof(**netlist));
	(*netlist)->name = name;
}

/* note a host as trustworthy */
static void
add_good_host(name, perm)
	char *name;
	int perm;			/* 1=not part of the netgroup */
{
	register struct goodhost *ghp;
	register struct hostent *hentp;

	ghp = (struct goodhost*)malloc(sizeof(*ghp));
	if (!ghp) {
		syslog(LOG_ERR, "malloc failed");
		exit(1);
	}

	bzero((char*)ghp, sizeof(*ghp));
	(void)strncpy(&ghp->name[0], name, sizeof(ghp->name));
	ghp->next = goodhosts;
	ghp->perm = perm;
	goodhosts = ghp;

	hentp = gethostbyname(name);
	if (0 == hentp && perm)
		(void)fprintf(stderr, "unknown host %s\n", name);
}


/* update our image of the net-group of trustworthy hosts
 */
void
get_goodgroup(force)
	int force;
{
# define NG_DELAY (30*60*CLK_TCK)	/* 30 minutes */
	static unsigned long last_update = -NG_DELAY;
	unsigned long new_update;
	struct hosttbl *htp;
	struct goodhost *ghp, **ghpp;
	char *mach, *usr, *dom;
	struct tms tm;


	/* if no netgroup, then we are finished */
	if (goodgroup == 0 || !Mflag)
		return;

	/* Do not chatter with the netgroup master too often.
	 */
	new_update = times(&tm);
	if (new_update < last_update + NG_DELAY
	    && !force)
		return;
	last_update = new_update;

	/* forget the old temporary entries */
	ghpp = &goodhosts;
	while (0 != (ghp = *ghpp)) {
		if (!ghp->perm) {
			*ghpp = ghp->next;
			free((char*)ghp);
		} else {
			ghpp = &ghp->next;
		}
	}

#ifdef HAVENIS
	/* quit now if we are not one of the trusted masters
	 */
	if (!innetgr(goodgroup, &hostname[0], 0,0)) {
		if (trace)
			(void)fprintf(fd, "get_goodgroup: %s not in %s\n",
				      &hostname[0], goodgroup);
		return;
	}
	if (trace)
		(void)fprintf(fd, "get_goodgroup: %s in %s\n",
				  &hostname[0], goodgroup);

	/* mark the entire netgroup as trusted */
	(void)setnetgrent(goodgroup);
	while (getnetgrent(&mach,&usr,&dom)) {
		if (0 != mach)
			add_good_host(mach,0);
	}
	(void)endnetgrent();

	/* update list of slaves */
	for (htp = self.l_fwd; htp != &self; htp = htp->l_fwd) {
		htp->good = good_host_name(&htp->name[0]);
	}
#endif /* HAVENIS */
}


/* see if a machine is trustworthy
 */
int					/* 1=trust hp to change our date */
good_host_name(name)
	char *name;
{
	register struct goodhost *ghp = goodhosts;
	register char c;

	if (!ghp || !Mflag)		/* trust everyone if no one named */
		return 1;

	c = *name;
	do {
		if (c == ghp->name[0]
		    && !strcasecmp(name, ghp->name))
			return 1;	/* found him, so say so */
	} while (0 != (ghp = ghp->next));

	if (!strcasecmp(name,hostname))	/* trust ourself */
		return 1;

	return 0;			/* did not find him */
}