syslogd.c

制作2.6内核的CLFS时 sysklogd-1.5.tar.gz包

		strcpy(tmpline, parts[fd]);
		free(parts[fd]);
		parts[fd] = (char *) 0;
		if ( (strlen(msg) + strlen(tmpline)) > MAXLINE )
		{
			logerror("Cannot glue message parts together");
			printline(hname, tmpline);
			start = msg;
		}
		else
		{
			dprintf("Previous: %s\n", tmpline);
			dprintf("Next: %s\n", msg);
			strcat(tmpline, msg);	/* length checked above */
			printline(hname, tmpline);
			if ( (strlen(msg) + 1) == len )
				return;
			else
				start = strchr(msg, '\0') + 1;
		}
	}

	if ( msg[len-1] != '\0' )
	{
		msg[len] = '\0';
		for(p= msg+len-1; *p != '\0' && p > msg; )
			--p;
		if(*p == '\0') p++;
		ptlngth = strlen(p);
		if ( (parts[fd] = malloc(ptlngth + 1)) == (char *) 0 )
			logerror("Cannot allocate memory for message part.");
		else
		{
			strcpy(parts[fd], p);
			dprintf("Saving partial msg: %s\n", parts[fd]);
			memset(p, '\0', ptlngth);
		}
	}

	do {
		end = strchr(start + 1, '\0');
		printline(hname, start);
		start = end + 1;
	} while ( *start != '\0' );

	return;
}



/*
 * Take a raw input line, decode the message, and print the message
 * on the appropriate log files.
 */

void printline(hname, msg)
	const char *hname;
	char *msg;
{
	register char *p, *q;
	register unsigned char c;
	char line[MAXLINE + 1];
	int pri;

	/* test for special codes */
	pri = DEFUPRI;
	p = msg;

	if (*p == '<') {
		pri = 0;
		while (isdigit(*++p))
		{
		   pri = 10 * pri + (*p - '0');
		}
		if (*p == '>')
			++p;
	}
	if (pri &~ (LOG_FACMASK|LOG_PRIMASK))
		pri = DEFUPRI;

	memset (line, 0, sizeof(line));
	q = line;
	while ((c = *p++) && q < &line[sizeof(line) - 4]) {
		if (c == '\n' || c == 127)
			*q++ = ' ';
		else if (c < 040) {
			*q++ = '^';
			*q++ = c ^ 0100;
		} else
			*q++ = c;
	}
	*q = '\0';

	logmsg(pri, line, hname, SYNC_FILE);
	return;
}



/*
 * Take a raw input line from /dev/klog, split and format similar to syslog().
 */

void printsys(msg)
	char *msg;
{
	register char *p, *q;
	register int c;
	char line[MAXLINE + 1];
	int pri, flags;
	char *lp;

	(void) snprintf(line, sizeof(line), "vmunix: ");
	lp = line + strlen(line);
	for (p = msg; *p != '\0'; ) {
		flags = ADDDATE;
		pri = DEFSPRI;
		if (*p == '<') {
			pri = 0;
			while (isdigit(*++p))
				pri = 10 * pri + (*p - '0');
			if (*p == '>')
				++p;
		} else {
			/* kernel printf's come out on console */
			flags |= IGN_CONS;
		}
		if (pri &~ (LOG_FACMASK|LOG_PRIMASK))
			pri = DEFSPRI;
		q = lp;
		while (*p != '\0' && (c = *p++) != '\n' &&
		    q < &line[MAXLINE])
			*q++ = c;
		*q = '\0';
		logmsg(pri, line, LocalHostName, flags);
	}
	return;
}

/*
 * Decode a priority into textual information like auth.emerg.
 */
char *textpri(pri)
	int pri;
{
	static char res[20];
	CODE *c_pri, *c_fac;

	for (c_fac = facilitynames; c_fac->c_name && !(c_fac->c_val == LOG_FAC(pri)<<3); c_fac++);
	for (c_pri = prioritynames; c_pri->c_name && !(c_pri->c_val == LOG_PRI(pri)); c_pri++);

	snprintf (res, sizeof(res), "%s.%s<%d>", c_fac->c_name, c_pri->c_name, pri);

	return res;
}

time_t	now;

/*
 * Log a message to the appropriate log files, users, etc. based on
 * the priority.
 */

void logmsg(pri, msg, from, flags)
	int pri;
	char *msg;
	const char *from;
	int flags;
{
	register struct filed *f;
	int fac, prilev, lognum;
	int msglen;
	char *timestamp;
#ifdef __gnu_linux__
	sigset_t mask;
#else
#ifndef SYSV
	sigset_t omask;
#endif
#endif

	dprintf("logmsg: %s, flags %x, from %s, msg %s\n", textpri(pri), flags, from, msg);

#ifdef __gnu_linux__
	sigemptyset(&mask);
	sigaddset(&mask, SIGHUP);
	sigaddset(&mask, SIGALRM);
	sigprocmask(SIG_BLOCK, &mask, NULL);
#else
#ifndef SYSV
	omask = sigblock(sigmask(SIGHUP)|sigmask(SIGALRM));
#endif
#endif

	/*
	 * Check to see if msg looks non-standard.
	 *
	 * A message looks like
	 * Nov 17 11:42:33 CRON[
	 * 01234567890123456
	 *    ^  ^  ^  ^  ^
	 *
	 * Remote messages are not accompanied by a timestamp.
	 * Local messages are accompanied by a timestamp (program's timezone)
	 */
	msglen = strlen(msg);
	if (!(msglen < 16 || msg[3] != ' ' || msg[6] != ' ' ||
	    msg[9] != ':' || msg[12] != ':' || msg[15] != ' ')) {
		msg += 16;
		msglen -= 16;
	}

	(void) time(&now);
	timestamp = ctime(&now) + 4;

	/* extract facility and priority level */
	fac = LOG_FAC(pri);
	prilev = LOG_PRI(pri);

	/* log the message to the particular outputs */
	if (!Initialized) {
		f = &consfile;
		f->f_file = open(ctty, O_WRONLY|O_NOCTTY);

		if (f->f_file >= 0) {
			untty();
			fprintlog(f, (char *)from, flags, msg);
			(void) close(f->f_file);
			f->f_file = -1;
		}
#ifdef __gnu_linux__
		sigprocmask(SIG_UNBLOCK, &mask, NULL);
#else
#ifndef SYSV
		(void) sigsetmask(omask);
#endif
#endif
		return;
	}
#ifdef SYSV
	for (lognum = 0; lognum <= nlogs; lognum++) {
		f = &Files[lognum];
#else
	for (f = Files; f; f = f->f_next) {
#endif

		/* skip messages that are incorrect priority */
		if ( (f->f_pmask[fac] == TABLE_NOPRI) || \
		    ((f->f_pmask[fac] & (1<<prilev)) == 0) )
		  	continue;

		if (f->f_type == F_CONSOLE && (flags & IGN_CONS))
			continue;

		/* don't output marks to recently written files */
		if ((flags & MARK) && (now - f->f_time) < MarkInterval / 2)
			continue;

		/*
		 * suppress duplicate lines to this file
		 */
		if ((flags & MARK) == 0 && msglen == f->f_prevlen &&
		    !strcmp(msg, f->f_prevline) &&
		    !strcmp(from, f->f_prevhost)) {
			(void) strncpy(f->f_lasttime, timestamp, 15);
			f->f_prevcount++;
			dprintf("msg repeated %d times, %ld sec of %d.\n",
			    f->f_prevcount, now - f->f_time,
			    repeatinterval[f->f_repeatcount]);
			/*
			 * If domark would have logged this by now,
			 * flush it now (so we don't hold isolated messages),
			 * but back off so we'll flush less often
			 * in the future.
			 */
			if (now > REPEATTIME(f)) {
				fprintlog(f, (char *)from, flags, (char *)NULL);
				BACKOFF(f);
			}
		} else {
			/* new line, save it */
			if (f->f_prevcount)
				fprintlog(f, (char *)from, 0, (char *)NULL);
			f->f_prevpri = pri;
			f->f_repeatcount = 0;
			(void) strncpy(f->f_lasttime, timestamp, 15);
			(void) strncpy(f->f_prevhost, from,
					sizeof(f->f_prevhost));
			if (msglen < MAXSVLINE) {
				f->f_prevlen = msglen;
				(void) strcpy(f->f_prevline, msg);
				fprintlog(f, (char *)from, flags, (char *)NULL);
			} else {
				f->f_prevline[0] = 0;
				f->f_prevlen = 0;
				fprintlog(f, (char *)from, flags, msg);
			}
		}
	}
#ifdef __gnu_linux__
	sigprocmask(SIG_UNBLOCK, &mask, NULL);
#else
#ifndef SYSV
	(void) sigsetmask(omask);
#endif
#endif
}
#if FALSE
} /* balance parentheses for emacs */
#endif

void fprintlog(f, from, flags, msg)
	register struct filed *f;
	char *from;
	int flags;
	char *msg;
{
	struct iovec iov[6];
	register struct iovec *v = iov;
	char repbuf[80];
#ifdef SYSLOG_INET
	register int l;
	char line[MAXLINE + 1];
	time_t fwd_suspend;
	struct hostent *hp;
#endif

	dprintf("Called fprintlog, ");

	v->iov_base = f->f_lasttime;
	v->iov_len = 15;
	v++;
	v->iov_base = " ";
	v->iov_len = 1;
	v++;
	v->iov_base = f->f_prevhost;
	v->iov_len = strlen(v->iov_base);
	v++;
	v->iov_base = " ";
	v->iov_len = 1;
	v++;
	if (msg) {
		v->iov_base = msg;
		v->iov_len = strlen(msg);
	} else if (f->f_prevcount > 1) {
		(void) snprintf(repbuf, sizeof(repbuf), "last message repeated %d times",
		    f->f_prevcount);
		v->iov_base = repbuf;
		v->iov_len = strlen(repbuf);
	} else {
		v->iov_base = f->f_prevline;
		v->iov_len = f->f_prevlen;
	}
	v++;

	dprintf("logging to %s", TypeNames[f->f_type]);

	switch (f->f_type) {
	case F_UNUSED:
		f->f_time = now;
		dprintf("\n");
		break;

#ifdef SYSLOG_INET
	case F_FORW_SUSP:
		fwd_suspend = time((time_t *) 0) - f->f_time;
		if ( fwd_suspend >= INET_SUSPEND_TIME ) {
			dprintf("\nForwarding suspension over, " \
				"retrying FORW ");
			f->f_type = F_FORW;
			goto f_forw;
		}
		else {
			dprintf(" %s\n", f->f_un.f_forw.f_hname);
			dprintf("Forwarding suspension not over, time " \
				"left: %d.\n", INET_SUSPEND_TIME - \
				fwd_suspend);
		}
		break;
		
	/*
	 * The trick is to wait some time, then retry to get the
	 * address. If that fails retry x times and then give up.
	 *
	 * You'll run into this problem mostly if the name server you
	 * need for resolving the address is on the same machine, but
	 * is started after syslogd. 
	 */
	case F_FORW_UNKN:
		dprintf(" %s\n", f->f_un.f_forw.f_hname);
		fwd_suspend = time((time_t *) 0) - f->f_time;
		if ( fwd_suspend >= INET_SUSPEND_TIME ) {
			dprintf("Forwarding suspension to unknown over, retrying\n");
			if ( (hp = gethostbyname(f->f_un.f_forw.f_hname)) == NULL ) {
				dprintf("Failure: %s\n", sys_h_errlist[h_errno]);
				dprintf("Retries: %d\n", f->f_prevcount);
				if ( --f->f_prevcount < 0 ) {
					dprintf("Giving up.\n");
					f->f_type = F_UNUSED;
				}
				else
					dprintf("Left retries: %d\n", f->f_prevcount);
			}
			else {
			        dprintf("%s found, resuming.\n", f->f_un.f_forw.f_hname);
				memcpy((char *) &f->f_un.f_forw.f_addr.sin_addr, hp->h_addr, hp->h_length);
				f->f_prevcount = 0;
				f->f_type = F_FORW;
				goto f_forw;
			}
		}
		else
			dprintf("Forwarding suspension not over, time " \
				"left: %d\n", INET_SUSPEND_TIME - fwd_suspend);
		break;

	case F_FORW:
		/* 
		 * Don't send any message to a remote host if it
		 * already comes from one. (we don't care 'bout who
		 * sent the message, we don't send it anyway)  -Joey
		 */
	f_forw:
		dprintf(" %s\n", f->f_un.f_forw.f_hname);
		if ( strcmp(from, LocalHostName) && NoHops )
			dprintf("Not sending message to remote.\n");
		else {
			f->f_time = now;
			(void) snprintf(line, sizeof(line), "<%d>%s", f->f_prevpri, \
				(char *) iov[4].iov_base);
			l = strlen(line);
			if (l > MAXLINE)
				l = MAXLINE;
			if (sendto(finet, line, l, 0, \
				   (struct sockaddr *) &f->f_un.f_forw.f_addr,
				   sizeof(f->f_un.f_forw.f_addr)) != l) {
				int e = errno;
				dprintf("INET sendto error: %d = %s.\n", 
					e, strerror(e));
				f->f_type = F_FORW_SUSP;
				errno = e;
				logerror("sendto");
			}
		}
		break;
#endif

	case F_CONSOLE:
		f->f_time = now;
#ifdef UNIXPC
		if (1) {
#else
		if (flags & IGN_CONS) {	
#endif
			dprintf(" (ignored).\n");
			break;
		}
		/* FALLTHROUGH */

	case F_TTY:
	case F_FILE:
	case F_PIPE:
		f->f_time = now;
		dprintf(" %s\n", f->f_un.f_fname);
		if (f->f_type == F_TTY || f->f_type == F_CONSOLE) {
			v->iov_base = "\r\n";
			v->iov_len = 2;
		} else {
			v->iov_base = "\n";
			v->iov_len = 1;
		}
	again:
		/* f->f_file == -1 is an indicator that we couldn't
		   open the file at startup. */
		if (f->f_file == -1)
			break;