db.c

DHCP服务器源码

	errno = 0;
	fputs ("\n}\n", db_file);
	if (errno) {
		++errors;
	}
	if (errors) {
		log_info ("write_host: unable to write host %s",
			  host -> name);
		lease_file_is_corrupt = 1;
	}
	return !errors;
}

int write_group (group)
	struct group_object *group;
{
	int errors = 0;
	int i;

	/* If the lease file is corrupt, don't try to write any more leases
	   until we've written a good lease file. */
	if (lease_file_is_corrupt)
		if (!new_lease_file ())
			return 0;

	if (!db_printable (group -> name))
		return 0;

	if (counting)
		++count;
	errno = 0;

	fprintf (db_file, "group %s {", group -> name);
	if (errno) {
		++errors;
	}

	if (group -> flags & GROUP_OBJECT_DYNAMIC) {
		errno = 0;
		fprintf (db_file, "\n  dynamic;");
		if (errno)
			++errors;
	}

	if (group -> flags & GROUP_OBJECT_STATIC) {
		errno = 0;
		fprintf (db_file, "\n  static;");
		if (errno)
			++errors;
	}

	if (group -> flags & GROUP_OBJECT_DELETED) {
		errno = 0;
		fprintf (db_file, "\n  deleted;");
		if (errno)
			++errors;
	} else {
		if (group -> group) {
			errno = 0;
			write_statements (db_file,
					  group -> group -> statements, 8);
			if (errno) {
				++errors;
			}
		}
	}

	errno = 0;
	fputs ("\n}\n", db_file);
	if (errno) {
		++errors;
	}
	if (errors) {
		log_info ("write_group: unable to write group %s",
			  group -> name);
		lease_file_is_corrupt = 1;
	}
	return !errors;
}

#if defined (FAILOVER_PROTOCOL)
int write_failover_state (dhcp_failover_state_t *state)
{
	struct tm *t;
	int errors = 0;

	if (lease_file_is_corrupt)
		if (!new_lease_file ())
			return 0;

	errno = 0;
	fprintf (db_file, "\nfailover peer \"%s\" state {", state -> name);
	if (errno)
		++errors;

	t = gmtime (&state -> me.stos);
	errno = 0;
	fprintf (db_file, "\n  my state %s at %d %d/%02d/%02d %02d:%02d:%02d;",
		 /* Never record our state as "startup"! */
		 (state -> me.state == startup
		  ? dhcp_failover_state_name_print (state -> saved_state)
		  : dhcp_failover_state_name_print (state -> me.state)),
		 t -> tm_wday, t -> tm_year + 1900,
		 t -> tm_mon + 1, t -> tm_mday,
		 t -> tm_hour, t -> tm_min, t -> tm_sec);
	if (errno)
		++errors;

	t = gmtime (&state -> partner.stos);
	errno = 0;
	fprintf (db_file,
		 "\n  partner state %s at %d %d/%02d/%02d %02d:%02d:%02d;",
		 dhcp_failover_state_name_print (state -> partner.state),
		 t -> tm_wday, t -> tm_year + 1900,
		 t -> tm_mon + 1, t -> tm_mday,
		 t -> tm_hour, t -> tm_min, t -> tm_sec);
	if (errno)
		++errors;

	if (state -> i_am == secondary) {
		errno = 0;
		fprintf (db_file, "\n  mclt %ld;",
			 (unsigned long)state -> mclt);
		if (errno)
			++errors;
	}
	fprintf (db_file, "\n}\n");
	if (errno)
		++errors;

	if (errors) {
		log_info ("write_failover_state: unable to write state %s",
			  state -> name);
		lease_file_is_corrupt = 1;
		return 0;
	}
	return 1;

}
#endif

int db_printable (s)
	const char *s;
{
	int i;
	for (i = 0; s [i]; i++)
		if (!isascii (s [i]) || !isprint (s [i])
		    || s [i] == '"' || s [i] == '\\')
			return 0;
	return 1;
}

int db_printable_len (s, len)
	const unsigned char *s;
	unsigned len;
{
	int i;
	for (i = 0; i < len; i++)
		if (!isascii (s [i]) || !isprint (s [i]) ||
		    s [i] == '"' || s [i] == '\\')
			return 0;
	return 1;
}

void write_named_billing_class (const char *name, unsigned len,
				struct class *class)
{
	/* XXX billing classes that are modified by OMAPI need
	   XXX to be detected and written out here. */
}

void write_billing_classes ()
{
	struct collection *lp;
	struct class *cp;
	struct hash_bucket *bp;
	int i;

	for (lp = collections; lp; lp = lp -> next) {
	    for (cp = lp -> classes; cp; cp = cp -> nic) {
		if (cp -> spawning && cp -> hash) {
		    class_hash_foreach (cp -> hash, write_named_billing_class);
		}
	    }
	}
}

/* Write a spawned class to the database file. */

int write_billing_class (class)
	struct class *class;
{
	int errors = 0;
	int i;

	if (lease_file_is_corrupt)
		if (!new_lease_file ())
			return 0;

	if (!class -> superclass) {
		errno = 0;
		fprintf (db_file, "\n  billing class \"%s\";", class -> name);
		return !errno;
	}

	errno = 0;
	fprintf (db_file, "\n  billing subclass \"%s\"",
		 class -> superclass -> name);
	if (errno)
		++errors;

	for (i = 0; i < class -> hash_string.len; i++)
		if (!isascii (class -> hash_string.data [i]) ||
		    !isprint (class -> hash_string.data [i]))
			break;
	if (i == class -> hash_string.len) {
		errno = 0;
		fprintf (db_file, " \"%.*s\";",
			 (int)class -> hash_string.len,
			 class -> hash_string.data);
		if (errno)
			++errors;
	} else {
		errno = 0;
		fprintf (db_file, " %2.2x", class -> hash_string.data [0]);
		if (errno)
			++errors;
		for (i = 1; i < class -> hash_string.len; i++) {
			errno = 0;
			fprintf (db_file, ":%2.2x",
				 class -> hash_string.data [i]);
			if (errno)
				++errors;
		}
		errno = 0;
		fprintf (db_file, ";");
		if (errno)
			++errors;
	}

	class -> dirty = !errors;
	if (errors)
		lease_file_is_corrupt = 1;
	return !errors;
}

/* Commit leases after a timeout. */
void commit_leases_timeout (void *foo)
{
	commit_leases ();
}

/* Commit any leases that have been written out... */

int commit_leases ()
{
	/* Commit any outstanding writes to the lease database file.
	   We need to do this even if we're rewriting the file below,
	   just in case the rewrite fails. */
	if (fflush (db_file) == EOF) {
		log_info ("commit_leases: unable to commit: %m");
		return 0;
	}
	if (fsync (fileno (db_file)) < 0) {
		log_info ("commit_leases: unable to commit: %m");
		return 0;
	}

	/* If we haven't rewritten the lease database in over an
	   hour, rewrite it now.  (The length of time should probably
	   be configurable. */
	if (count && cur_time - write_time > 3600) {
		count = 0;
		write_time = cur_time;
		new_lease_file ();
	}
	return 1;
}

void db_startup (testp)
	int testp;
{
	isc_result_t status;

#if defined (TRACING)
	if (!trace_playback ()) {
#endif
		/* Read in the existing lease file... */
		status = read_conf_file (path_dhcpd_db,
					 (struct group *)0, 0, 1);
		/* XXX ignore status? */
#if defined (TRACING)
	}
#endif

#if defined (TRACING)
	/* If we're playing back, there is no lease file, so we can't
	   append it, so we create one immediately (maybe this isn't
	   the best solution... */
	if (trace_playback ()) {
		new_lease_file ();
	}
#endif
	if (!testp) {
		db_file = fopen (path_dhcpd_db, "a");
		if (!db_file)
			log_fatal ("Can't open %s for append.", path_dhcpd_db);
		expire_all_pools ();
#if defined (TRACING)
		if (trace_playback ())
			write_time = cur_time;
		else
#endif
			GET_TIME (&write_time);
		new_lease_file ();
	}
}

int new_lease_file ()
{
	char newfname [512];
	char backfname [512];
	TIME t;
	int db_fd;

	/* If we already have an open database, close it. */
	if (db_file) {
		fclose (db_file);
		db_file = (FILE *)0;
	}

	/* Make a temporary lease file... */
	GET_TIME (&t);

	/* %Audit% Truncated filename causes panic. %2004.06.17,Safe%
	 * This should never happen since the path is a configuration
	 * variable from build-time or command-line.  But if it should,
	 * either by malice or ignorance, we panic, since the potential
	 * for havoc is high.
	 */
	if (snprintf (newfname, sizeof newfname, "%s.%d",
		     path_dhcpd_db, (int)t) >= sizeof newfname)
		log_fatal("new_lease_file: lease file path too long");

	db_fd = open (newfname, O_WRONLY | O_TRUNC | O_CREAT, 0664);
	if (db_fd < 0) {
		log_error ("Can't create new lease file: %m");
		return 0;
	}
	if ((db_file = fdopen (db_fd, "w")) == NULL) {
		log_error ("Can't fdopen new lease file!");
		goto fail;
	}

	/* Write an introduction so people don't complain about time
	   being off. */
	errno = 0;
	fprintf (db_file, "# All times in this file are in UTC (GMT), not %s",
		 "your local timezone.   This is\n");
	if (errno != 0)
		goto fail;
	fprintf (db_file, "# not a bug, so please don't ask about it.   %s",
		 "There is no portable way to\n");
	if (errno != 0)
		goto fail;
	fprintf (db_file, "# store leases in the local timezone, so please %s",
		 "don't request this as a\n");
	if (errno != 0)
		goto fail;
	fprintf (db_file, "# feature.   If this is inconvenient or %s",
		 "confusing to you, we sincerely\n");
	if (errno != 0)
		goto fail;
	fprintf (db_file, "# apologize.   Seriously, though - don't ask.\n");
	if (errno != 0)
		goto fail;
	fprintf (db_file, "# The format of this file is documented in the %s",
		 "dhcpd.leases(5) manual page.\n");
	if (errno != 0)
		goto fail;
	fprintf (db_file, "# This lease file was written by isc-dhcp-%s\n\n",
		 DHCP_VERSION);
	if (errno != 0)
		goto fail;

	/* Write out all the leases that we know of... */
	counting = 0;
	if (!write_leases ())
		goto fail;

#if defined (TRACING)
	if (!trace_playback ()) {
#endif
	    /* %Audit% Truncated filename causes panic. %2004.06.17,Safe%
	     * This should never happen since the path is a configuration
	     * variable from build-time or command-line.  But if it should,
	     * either by malice or ignorance, we panic, since the potential
	     * for havoc is too high.
	     */
	    if (snprintf (backfname, sizeof backfname, "%s~", path_dhcpd_db)
			>= sizeof backfname)
		log_fatal("new_lease_file: backup lease file path too long");

	    /* Get the old database out of the way... */
	    if (unlink (backfname) < 0 && errno != ENOENT) {
		log_error ("Can't remove old lease database backup %s: %m",
			   backfname);
		goto fail;
	    }
	    if (link (path_dhcpd_db, backfname) < 0) {
		log_error ("Can't backup lease database %s to %s: %m",
			   path_dhcpd_db, backfname);
		goto fail;
	    }
#if defined (TRACING)
	}
#endif
	
	/* Move in the new file... */
	if (rename (newfname, path_dhcpd_db) < 0) {
		log_error ("Can't install new lease database %s to %s: %m",
			   newfname, path_dhcpd_db);
		goto fail;
	}

	counting = 1;
	lease_file_is_corrupt = 0;
	return 1;

      fail:
	unlink (newfname);
	lease_file_is_corrupt = 1;
	return 0;
}

int group_writer (struct group_object *group)
{
	if (!write_group (group))
		return 0;
	if (!commit_leases ())
		return 0;
	return 1;
}