/*      $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>
#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, "gnore"))
                        return (IGNORE);
                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);
                if (!strcasecmp(atom + 1, "lan-pcp"))
                        return (VLAN_PCP);
                break;
        case 'y':
                if (!strcasecmp(atom + 1, "iaddr"))
                        return (YIADDR);
                break;
        }
        return (dfv);
}