syslogd.c

制作2.6内核的CLFS时 sysklogd-1.5.tar.gz包

		if (writev(f->f_file, iov, 6) < 0) {
			int e = errno;

			/* If a named pipe is full, just ignore it for now */
			if (f->f_type == F_PIPE && e == EAGAIN)
				break;

			/* If the filesystem is filled up, just ignore
			   it for now and continue writing when
			   possible */
			if (f->f_type == F_FILE && e == ENOSPC)
				break;

			(void) close(f->f_file);
			/*
			 * Check for EBADF on TTY's due to vhangup() XXX
			 * Linux uses EIO instead (mrn 12 May 96)
			 */
			if ((f->f_type == F_TTY || f->f_type == F_CONSOLE)
#ifdef linux
				&& e == EIO) {
#else
				&& e == EBADF) {
#endif
				f->f_file = open(f->f_un.f_fname, O_WRONLY|O_APPEND|O_NOCTTY);
				if (f->f_file < 0) {
					f->f_type = F_UNUSED;
					logerror(f->f_un.f_fname);
				} else {
					untty();
					goto again;
				}
			} else {
				f->f_type = F_UNUSED;
				errno = e;
				logerror(f->f_un.f_fname);
			}
		} else if (f->f_type == F_FILE && (f->f_flags & SYNC_FILE))
			(void) fsync(f->f_file);
		break;

	case F_USERS:
	case F_WALL:
		f->f_time = now;
		dprintf("\n");
		v->iov_base = "\r\n";
		v->iov_len = 2;
		wallmsg(f, iov);
		break;
	} /* switch */
	if (f->f_type != F_FORW_UNKN)
		f->f_prevcount = 0;
	return;		
}
#if FALSE
}} /* balance parentheses for emacs */
#endif

jmp_buf ttybuf;

void endtty()
{
	longjmp(ttybuf, 1);
}

/*
 *  WALLMSG -- Write a message to the world at large
 *
 *	Write the specified message to either the entire
 *	world, or a list of approved users.
 */

void wallmsg(f, iov)
	register struct filed *f;
	struct iovec *iov;
{
	char p[sizeof (_PATH_DEV) + UNAMESZ];
	register int i;
	int ttyf, len;
	static int reenter = 0;
	struct utmp ut;
	struct utmp *uptr;
	char greetings[200];

	(void) &len;

	if (reenter++)
		return;

	/* open the user login file */
	setutent();


	/*
	 * Might as well fork instead of using nonblocking I/O
	 * and doing notty().
	 */
	if (fork() == 0) {
		(void) signal(SIGTERM, SIG_DFL);
		(void) alarm(0);
#ifndef SYSV
		(void) signal(SIGTTOU, SIG_IGN);
		(void) sigsetmask(0);
#endif
		(void) snprintf(greetings, sizeof(greetings),
		    "\r\n\7Message from syslogd@%s at %.24s ...\r\n",
			(char *) iov[2].iov_base, ctime(&now));
		len = strlen(greetings);

		/* scan the user login file */
		while ((uptr = getutent())) {
			memcpy(&ut, uptr, sizeof(ut));
			/* is this slot used? */
			if (ut.ut_name[0] == '\0')
				continue;
			if (ut.ut_type != USER_PROCESS)
			        continue;
			if (!(strcmp (ut.ut_name,"LOGIN"))) /* paranoia */
			        continue;

			/* should we send the message to this user? */
			if (f->f_type == F_USERS) {
				for (i = 0; i < MAXUNAMES; i++) {
					if (!f->f_un.f_uname[i][0]) {
						i = MAXUNAMES;
						break;
					}
					if (strncmp(f->f_un.f_uname[i],
					    ut.ut_name, UNAMESZ) == 0)
						break;
				}
				if (i >= MAXUNAMES)
					continue;
			}

			/* compute the device name */
			strcpy(p, _PATH_DEV);
			strncat(p, ut.ut_line, UNAMESZ);

			if (f->f_type == F_WALL) {
				iov[0].iov_base = greetings;
				iov[0].iov_len = len;
				iov[1].iov_len = 0;
			}
			if (setjmp(ttybuf) == 0) {
				(void) signal(SIGALRM, endtty);
				(void) alarm(15);
				/* open the terminal */
				ttyf = open(p, O_WRONLY|O_NOCTTY);
				if (ttyf >= 0) {
					struct stat statb;

					if (fstat(ttyf, &statb) == 0 &&
					    (statb.st_mode & S_IWRITE))
						(void) writev(ttyf, iov, 6);
					close(ttyf);
					ttyf = -1;
				}
			}
			(void) alarm(0);
		}
		exit(0);
	}
	/* close the user login file */
	endutent();
	reenter = 0;
}

void reapchild()
{
	int saved_errno = errno;
#if defined(SYSV) && !defined(linux)
	(void) signal(SIGCHLD, reapchild);	/* reset signal handler -ASP */
	wait ((int *)0);
#else
	union wait status;

	while (wait3(&status, WNOHANG, (struct rusage *) NULL) > 0)
		;
#endif
#ifdef linux
	(void) signal(SIGCHLD, reapchild);	/* reset signal handler -ASP */
#endif
	errno = saved_errno;
}

/*
 * Return a printable representation of a host address.
 */
const char *cvthname(f)
	struct sockaddr_in *f;
{
	struct hostent *hp;
	register char *p;
	int count;

	if (f->sin_family != AF_INET) {
		dprintf("Malformed from address.\n");
		return ("???");
	}
	hp = gethostbyaddr((char *) &f->sin_addr, sizeof(struct in_addr), \
			   f->sin_family);
	if (hp == 0) {
		dprintf("Host name for your address (%s) unknown.\n",
			inet_ntoa(f->sin_addr));
		return (inet_ntoa(f->sin_addr));
	}
	/*
	 * Convert to lower case, just like LocalDomain above
	 */
	for (p = (char *)hp->h_name; *p ; p++)
		if (isupper(*p))
			*p = tolower(*p);

	/*
	 * Notice that the string still contains the fqdn, but your
	 * hostname and domain are separated by a '\0'.
	 */
	if ((p = strchr(hp->h_name, '.'))) {
		if (strcmp(p + 1, LocalDomain) == 0) {
			*p = '\0';
			return (hp->h_name);
		} else {
			if (StripDomains) {
				count=0;
				while (StripDomains[count]) {
					if (strcmp(p + 1, StripDomains[count]) == 0) {
						*p = '\0';
						return (hp->h_name);
					}
					count++;
				}
			}
			if (LocalHosts) {
				count=0;
				while (LocalHosts[count]) {
					if (!strcmp(hp->h_name, LocalHosts[count])) {
						*p = '\0';
						return (hp->h_name);
					}
					count++;
				}
			}
		}
	}

	return (hp->h_name);
}

void domark()
{
	register struct filed *f;
#ifdef SYSV
	int lognum;
#endif

	if (MarkInterval > 0) {
	now = time(0);
	MarkSeq += TIMERINTVL;
	if (MarkSeq >= MarkInterval) {
		logmsg(LOG_MARK|LOG_INFO, "-- MARK --", LocalHostName, ADDDATE|MARK);
		MarkSeq = 0;
	}

#ifdef SYSV
	for (lognum = 0; lognum <= nlogs; lognum++) {
		f = &Files[lognum];
#else
	for (f = Files; f; f = f->f_next) {
#endif
		if (f->f_prevcount && now >= REPEATTIME(f)) {
			dprintf("flush %s: repeated %d times, %d sec.\n",
			    TypeNames[f->f_type], f->f_prevcount,
			    repeatinterval[f->f_repeatcount]);
			fprintlog(f, LocalHostName, 0, (char *)NULL);
			BACKOFF(f);
		}
	}
	}
	(void) signal(SIGALRM, domark);
	(void) alarm(TIMERINTVL);
}

void debug_switch()

{
	dprintf("Switching debugging_on to %s\n", (debugging_on == 0) ? "true" : "false");
	debugging_on = (debugging_on == 0) ? 1 : 0;
	signal(SIGUSR1, debug_switch);
}


/*
 * Print syslogd errors some place.
 */
void logerror(type)
	char *type;
{
	char buf[100];

	dprintf("Called logerr, msg: %s\n", type);

	if (errno == 0)
		(void) snprintf(buf, sizeof(buf), "syslogd: %s", type);
	else
		(void) snprintf(buf, sizeof(buf), "syslogd: %s: %s", type, strerror(errno));
	errno = 0;
	logmsg(LOG_SYSLOG|LOG_ERR, buf, LocalHostName, ADDDATE);
	return;
}

void die(sig)

	int sig;
	
{
	register struct filed *f;
	char buf[100];
	int lognum;
	int i;
	int was_initialized = Initialized;

	Initialized = 0;	/* Don't log SIGCHLDs in case we
				   receive one during exiting */

	for (lognum = 0; lognum <= nlogs; lognum++) {
		f = &Files[lognum];
		/* flush any pending output */
		if (f->f_prevcount)
			fprintlog(f, LocalHostName, 0, (char *)NULL);
	}

	Initialized = was_initialized;
	if (sig) {
		dprintf("syslogd: exiting on signal %d\n", sig);
		(void) snprintf(buf, sizeof(buf), "exiting on signal %d", sig);
		errno = 0;
		logmsg(LOG_SYSLOG|LOG_INFO, buf, LocalHostName, ADDDATE);
	}

	/* Close the UNIX sockets. */
        for (i = 0; i < nfunix; i++)
		if (funix[i] != -1)
			close(funix[i]);
	/* Close the inet socket. */
	if (InetInuse) close(inetm);

	/* Clean-up files. */
        for (i = 0; i < nfunix; i++)
		if (funixn[i] && funix[i] != -1)
			(void)unlink(funixn[i]);
#ifndef TESTING
	(void) remove_pid(PidFile);
#endif
	exit(0);
}

/*
 * Signal handler to terminate the parent process.
 */
#ifndef TESTING
void doexit(sig)
	int sig;
{
	exit (0);
}
#endif

/*
 *  INIT -- Initialize syslogd from configuration table
 */

void init()
{
	register int i, lognum;
	register FILE *cf;
	register struct filed *f;
#ifndef TESTING
#ifndef SYSV
	register struct filed **nextp = (struct filed **) 0;
#endif
#endif
	register char *p;
	register unsigned int Forwarding = 0;
#ifdef CONT_LINE
	char cbuf[BUFSIZ];
	char *cline;
#else
	char cline[BUFSIZ];
#endif
	struct servent *sp;

	sp = getservbyname("syslog", "udp");
	if (sp == NULL) {
		if (errno == ENOENT) {
			errno = 0;
			logerror("The file /etc/services does not seem exist.");
		}
		errno = 0;
		logerror("network logging disabled (syslog/udp service unknown).");
		logerror("see syslogd(8) for details of whether and how to enable it.");
		LogPort = 0;
	} else
	LogPort = sp->s_port;

	/*
	 *  Close all open log files and free log descriptor array.
	 */
	dprintf("Called init.\n");
	Initialized = 0;
	if ( nlogs > -1 )
	{
		dprintf("Initializing log structures.\n");

		for (lognum = 0; lognum <= nlogs; lognum++ ) {
			f = &Files[lognum];

			/* flush any pending output */
			if (f->f_prevcount)
				fprintlog(f, LocalHostName, 0, (char *)NULL);

			switch (f->f_type) {
				case F_FILE:
				case F_PIPE:
				case F_TTY:
				case F_CONSOLE:
					(void) close(f->f_file);
				break;
			}
		}

		/*
		 * This is needed especially when HUPing syslogd as the
		 * structure would grow infinitively.  -Joey
		 */
		nlogs = -1;
		free((void *) Files);
		Files = (struct filed *) 0;
	}
	

#ifdef SYSV
	lognum = 0;
#else
	f = NULL;
#endif

	/* open the configuration file */
	if ((cf = fopen(ConfFile, "r")) == NULL) {
		dprintf("cannot open %s.\n", ConfFile);
#ifdef SYSV
		allocate_log();
		f = &Files[lognum++];
#ifndef TESTING
		cfline("*.err\t" _PATH_CONSOLE, f);
#else
		snprintf(cbuf,sizeof(cbuf), "*.*\t%s", ttyname(0));
		cfline(cbuf, f);
#endif
#else
		*nextp = (struct filed *)calloc(1, sizeof(*f));
		cfline("*.ERR\t" _PATH_CONSOLE, *nextp);
		(*nextp)->f_next = (struct filed *)calloc(1, sizeof(*f))	/* ASP */
		cfline("*.PANIC\t*", (*nextp)->f_next);
#endif
		Initialized = 1;
		return;
	}

	/*
	 *  Foreach line in the conf table, open that file.
	 */
#if CONT_LINE
	cl