/*	$OpenBSD: conflex.c,v 1.7 2004/09/15 19:02:38 deraadt Exp $	*/

/* Lexical scanner for dhcpd config file... */

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1995, 1996, 1997 The Internet Software Consortium.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of The Internet Software Consortium nor the names
 *    of its contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * This software has been written for the Internet Software Consortium
 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
 * Enterprises.  To learn more about the Internet Software Consortium,
 * see ``http://www.vix.com/isc''.  To learn more about Vixie
 * Enterprises, see ``http://www.vix.com''.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <ctype.h>

#include "dhcpd.h"
#include "dhctoken.h"

int lexline;
int lexchar;
char *token_line;
static char *prev_line;
static char *cur_line;
const char *tlname;
int eol_token;

static char line1[81];
static char line2[81];
static unsigned lpos;
static unsigned line;
static int tlpos;
static int tline;
static int token;
static int ugflag;
static char *tval;
static char tokbuf[1500];

static int get_char(FILE *);
static int get_token(FILE *);
static void skip_to_eol(FILE *);
static int read_string(FILE *);
static int read_number(int, FILE *);
static int read_num_or_name(int, FILE *);
static int intern(char *, int);

void
new_parse(const char *name)
{
	tlname = name;
	lpos = line = 1;
	cur_line = line1;
	prev_line = line2;
	token_line = cur_line;
	cur_line[0] = prev_line[0] = 0;
	warnings_occurred = 0;
}

static int
get_char(FILE *cfile)
{
	int c = getc(cfile);
	if (!ugflag) {
		if (c == '\n') {
			if (cur_line == line1) {
				cur_line = line2;
				prev_line = line1;
			} else {
				cur_line = line1;
				prev_line = line2;
			}
			line++;
			lpos = 1;
			cur_line[0] = 0;
		} else if (c != EOF) {
			if (lpos < sizeof(line1)) {
				cur_line[lpos - 1] = c;
				cur_line[lpos] = 0;
			}
			lpos++;
		}
	} else
		ugflag = 0;
	return (c);
}

static int
get_token(FILE *cfile)
{
	int		c, ttok;
	static char	tb[2];
	int		l, p;

	do {
		l = line;
		p = lpos;

		c = get_char(cfile);

		if (!(c == '\n' && eol_token) && isascii(c) && isspace(c))
			continue;
		if (c == '#') {
			skip_to_eol(cfile);
			continue;
		}
		if (c == '"') {
			lexline = l;
			lexchar = p;
			ttok = read_string(cfile);
			break;
		}
		if ((isascii(c) && isdigit(c)) || c == '-') {
			lexline = l;
			lexchar = p;
			ttok = read_number(c, cfile);
			break;
		} else if (isascii(c) && isalpha(c)) {
			lexline = l;
			lexchar = p;
			ttok = read_num_or_name(c, cfile);
			break;
		} else {
			lexline = l;
			lexchar = p;
			tb[0] = c;
			tb[1] = 0;
			tval = tb;
			ttok = c;
			break;
		}
	} while (1);
	return (ttok);
}

int
next_token(char **rval, FILE *cfile)
{
	int	rv;

	if (token) {
		if (lexline != tline)
			token_line = cur_line;
		lexchar = tlpos;
		lexline = tline;
		rv = token;
		token = 0;
	} else {
		rv = get_token(cfile);
		token_line = cur_line;
	}
	if (rval)
		*rval = tval;

	return (rv);
}

int
peek_token(char **rval, FILE *cfile)
{
	int	x;

	if (!token) {
		tlpos = lexchar;
		tline = lexline;
		token = get_token(cfile);
		if (lexline != tline)
			token_line = prev_line;
		x = lexchar;
		lexchar = tlpos;
		tlpos = x;
		x = lexline;
		lexline = tline;
		tline = x;
	}
	if (rval)
		*rval = tval;

	return (token);
}

static void
skip_to_eol(FILE *cfile)
{
	int	c;

	do {
		c = get_char(cfile);
		if (c == EOF)
			return;
		if (c == '\n')
			return;
	} while (1);
}

static int
read_string(FILE *cfile)
{
	int	c, bs = 0;
	unsigned i;

	for (i = 0; i < sizeof(tokbuf); i++) {
		c = get_char(cfile);
		if (c == EOF) {
			parse_warn("eof in string constant");
			break;
		}
		if (bs) {
			bs = 0;
			i--;
			tokbuf[i] = c;
		} else if (c == '\\')
			bs = 1;
		else if (c == '"')
			break;
		else
			tokbuf[i] = c;
	}
	/*
	 * Normally, I'd feel guilty about this, but we're talking about
	 * strings that'll fit in a DHCP packet here...
	 */
	if (i == sizeof(tokbuf)) {
		parse_warn("string constant larger than internal buffer");
		i--;
	}
	tokbuf[i] = 0;
	tval = tokbuf;
	return (STRING);
}

static int
read_number(int c, FILE *cfile)
{
	int	seenx = 0, _token = NUMBER;
	unsigned i = 0;

	tokbuf[i++] = c;
	for (; i < sizeof(tokbuf); i++) {
		c = get_char(cfile);
		if (!seenx && c == 'x')
			seenx = 1;
		else if (!isascii(c) || !isxdigit(c)) {
			ungetc(c, cfile);
			ugflag = 1;
			break;
		}
		tokbuf[i] = c;
	}
	if (i == sizeof(tokbuf)) {
		parse_warn("numeric token larger than internal buffer");
		i--;
	}
	tokbuf[i] = 0;
	tval = tokbuf;

	return (_token);
}

static int
read_num_or_name(int c, FILE *cfile)
{
	unsigned i = 0;
	int	rv = NUMBER_OR_NAME;

	tokbuf[i++] = c;
	for (; i < sizeof(tokbuf); i++) {
		c = get_char(cfile);
		if (!isascii(c) || (c != '-' && c != '_' && !isalnum(c))) {
			ungetc(c, cfile);
			ugflag = 1;
			break;
		}
		if (!isxdigit(c))
			rv = NAME;
		tokbuf[i] = c;
	}
	if (i == sizeof(tokbuf)) {
		parse_warn("token larger than internal buffer");
		i--;
	}
	tokbuf[i] = 0;
	tval = tokbuf;

	return (intern(tval, rv));
}

static int
intern(char *atom, int dfv)
{
	if (!isascii(atom[0]))
		return (dfv);

	switch (tolower(atom[0])) {
	case 'a':
		if (!strcasecmp(atom + 1, "lways-reply-rfc1048"))
			return (ALWAYS_REPLY_RFC1048);
		if (!strcasecmp(atom + 1, "ppend"))
			return (APPEND);
		if (!strcasecmp(atom + 1, "llow"))
			return (ALLOW);
		if (!strcasecmp(atom + 1, "lias"))
			return (ALIAS);
		if (!strcasecmp(atom + 1, "bandoned"))
			return (ABANDONED);
		if (!strcasecmp(atom + 1, "uthoritative"))
			return (AUTHORITATIVE);
		break;
	case 'b':
		if (!strcasecmp(atom + 1, "ackoff-cutoff"))
			return (BACKOFF_CUTOFF);
		if (!strcasecmp(atom + 1, "ootp"))
			return (BOOTP);
		if (!strcasecmp(atom + 1, "ooting"))
			return (BOOTING);
		if (!strcasecmp(atom + 1, "oot-unknown-clients"))
			return (BOOT_UNKNOWN_CLIENTS);
		break;
	case 'c':
		if (!strcasecmp(atom + 1, "lass"))
			return (CLASS);
		if (!strcasecmp(atom + 1, "iaddr"))
			return (CIADDR);
		if (!strcasecmp(atom + 1, "lient-identifier"))
			return (CLIENT_IDENTIFIER);
		if (!strcasecmp(atom + 1, "lient-hostname"))
			return (CLIENT_HOSTNAME);
		break;
	case 'd':
		if (!strcasecmp(atom + 1, "omain"))
			return (DOMAIN);
		if (!strcasecmp(atom + 1, "eny"))
			return (DENY);
		if (!strncasecmp(atom + 1, "efault", 6)) {
			if (!atom[7])
				return (DEFAULT);
			if (!strcasecmp(atom + 7, "-lease-time"))
				return (DEFAULT_LEASE_TIME);
			break;
		}
		if (!strncasecmp(atom + 1, "ynamic-bootp", 12)) {
			if (!atom[13])
				return (DYNAMIC_BOOTP);
			if (!strcasecmp(atom + 13, "-lease-cutoff"))
				return (DYNAMIC_BOOTP_LEASE_CUTOFF);
			if (!strcasecmp(atom + 13, "-lease-length"))
				return (DYNAMIC_BOOTP_LEASE_LENGTH);
			break;
		}
		break;
	case 'e':
		if (!strcasecmp(atom + 1, "thernet"))
			return (ETHERNET);
		if (!strcasecmp(atom + 1, "nds"))
			return (ENDS);
		if (!strcasecmp(atom + 1, "xpire"))
			return (EXPIRE);
		break;
	case 'f':
		if (!strcasecmp(atom + 1, "ilename"))
			return (FILENAME);
		if (!strcasecmp(atom + 1, "ixed-address"))
			return (FIXED_ADDR);
		if (!strcasecmp(atom + 1, "ddi"))
			return (FDDI);
		break;
	case 'g':
		if (!strcasecmp(atom + 1, "iaddr"))
			return (GIADDR);
		if (!strcasecmp(atom + 1, "roup"))
			return (GROUP);
		if (!strcasecmp(atom + 1, "et-lease-hostnames"))
			return (GET_LEASE_HOSTNAMES);
		break;
	case 'h':
		if (!strcasecmp(atom + 1, "ost"))
			return (HOST);
		if (!strcasecmp(atom + 1, "ardware"))
			return (HARDWARE);
		if (!strcasecmp(atom + 1, "ostname"))
			return (HOSTNAME);
		break;
	case 'i':
		if (!strcasecmp(atom + 1, "nitial-interval"))
			return (INITIAL_INTERVAL);
		if (!strcasecmp(atom + 1, "nterface"))
			return (INTERFACE);
		break;
	case 'l':
		if (!strcasecmp(atom + 1, "ease"))
			return (LEASE);
		break;
	case 'm':
		if (!strcasecmp(atom + 1, "ax-lease-time"))
			return (MAX_LEASE_TIME);
		if (!strncasecmp(atom + 1, "edi", 3)) {
			if (!strcasecmp(atom + 4, "a"))
				return (MEDIA);
			if (!strcasecmp(atom + 4, "um"))
				return (MEDIUM);
			break;
		}
		break;
	case 'n':
		if (!strcasecmp(atom + 1, "ameserver"))
			return (NAMESERVER);
		if (!strcasecmp(atom + 1, "etmask"))
			return (NETMASK);
		if (!strcasecmp(atom + 1, "ext-server"))
			return (NEXT_SERVER);
		if (!strcasecmp(atom + 1, "ot"))
			return (TOKEN_NOT);
		break;
	case 'o':
		if (!strcasecmp(atom + 1, "ption"))
			return (OPTION);
		if (!strcasecmp(atom + 1, "ne-lease-per-client"))
			return (ONE_LEASE_PER_CLIENT);
		break;
	case 'p':
		if (!strcasecmp(atom + 1, "repend"))
			return (PREPEND);
		if (!strcasecmp(atom + 1, "acket"))
			return (PACKET);
		break;
	case 'r':
		if (!strcasecmp(atom + 1, "ange"))
			return (RANGE);
		if (!strcasecmp(atom + 1, "equest"))
			return (REQUEST);
		if (!strcasecmp(atom + 1, "equire"))
			return (REQUIRE);
		if (!strcasecmp(atom + 1, "etry"))
			return (RETRY);
		if (!strcasecmp(atom + 1, "enew"))
			return (RENEW);
		if (!strcasecmp(atom + 1, "ebind"))
			return (REBIND);
		if (!strcasecmp(atom + 1, "eboot"))
			return (REBOOT);
		if (!strcasecmp(atom + 1, "eject"))
			return (REJECT);
		break;
	case 's':
		if (!strcasecmp(atom + 1, "earch"))
			return (SEARCH);
		if (!strcasecmp(atom + 1, "tarts"))
			return (STARTS);
		if (!strcasecmp(atom + 1, "iaddr"))
			return (SIADDR);
		if (!strcasecmp(atom + 1, "ubnet"))
			return (SUBNET);
		if (!strcasecmp(atom + 1, "hared-network"))
			return (SHARED_NETWORK);
		if (!strcasecmp(atom + 1, "erver-name"))
			return (SERVER_NAME);
		if (!strcasecmp(atom + 1, "erver-identifier"))
			return (SERVER_IDENTIFIER);
		if (!strcasecmp(atom + 1, "elect-timeout"))
			return (SELECT_TIMEOUT);
		if (!strcasecmp(atom + 1, "end"))
			return (SEND);
		if (!strcasecmp(atom + 1, "cript"))
			return (SCRIPT);
		if (!strcasecmp(atom + 1, "upersede"))
			return (SUPERSEDE);
		break;
	case 't':
		if (!strcasecmp(atom + 1, "imestamp"))
			return (TIMESTAMP);
		if (!strcasecmp(atom + 1, "imeout"))
			return (TIMEOUT);
		if (!strcasecmp(atom + 1, "oken-ring"))
			return (TOKEN_RING);
		break;
	case 'u':
		if (!strncasecmp(atom + 1, "se", 2)) {
			if (!strcasecmp(atom + 3, "r-class"))
				return (USER_CLASS);
			if (!strcasecmp(atom + 3, "-host-decl-names"))
				return (USE_HOST_DECL_NAMES);
			if (!strcasecmp(atom + 3,
					 "-lease-addr-for-default-route"))
				return (USE_LEASE_ADDR_FOR_DEFAULT_ROUTE);
			break;
		}
		if (!strcasecmp(atom + 1, "id"))
			return (UID);
		if (!strcasecmp(atom + 1, "nknown-clients"))
			return (UNKNOWN_CLIENTS);
		break;
	case 'v':
		if (!strcasecmp(atom + 1, "endor-class"))
			return (VENDOR_CLASS);
		break;
	case 'y':
		if (!strcasecmp(atom + 1, "iaddr"))
			return (YIADDR);
		break;
	}
	return (dfv);
}