/*      $OpenBSD: src/sbin/dhclient/conflex.c,v 1.15 2012/08/22 00:14:42 tedu Exp $     */

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

/*
 * 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 <ctype.h>

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

int lexline;
int lexchar;
char *token_line;
char *prev_line;
char *cur_line;
char *tlname;

static char line1[81];
static char line2[81];
static uint lpos;
static int 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 *);
int kw_cmp(const void *, const void *);
static int intern(char *, int);

void
new_parse(char *name)
{
        /*
         * Initialize all parsing state, as we are starting to parse a
         * new file, 'name'.
         */

        bzero(line1, sizeof(line1));
        bzero(line2, sizeof(line2));
        bzero(tokbuf, sizeof(tokbuf));

        lpos = line = 1;
        tlpos = tline = token = ugflag = 0;
        tval = NULL;

        lexline = lexchar = 0;
        cur_line = line1;
        prev_line = line2;
        token_line = cur_line;
        tlname = name;

        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 = line2;
                                prev_line = line1;
                        }
                        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 (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)
{
        uint    i;
        int     c, bs = 0;

        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;
                        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 (TOK_STRING);
}

static int
read_number(int c, FILE *cfile)
{
        uint    i = 0;
        int     seenx = 0, token = TOK_NUMBER;

        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)
{
        uint    i = 0;
        int     rv = TOK_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 = TOK_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 const struct keywords {
        const char      *k_name;
        int             k_val;
} keywords[] = {
        { "alias",                              TOK_ALIAS },
        { "append",                             TOK_APPEND },
        { "backoff-cutoff",                     TOK_BACKOFF_CUTOFF },
        { "bootp",                              TOK_BOOTP },
        { "default",                            TOK_DEFAULT },
        { "deny",                               TOK_DENY },
        { "ethernet",                           TOK_ETHERNET },
        { "expire",                             TOK_EXPIRE },
        { "fddi",                               TOK_FDDI },
        { "filename",                           TOK_FILENAME },
        { "fixed-address",                      TOK_FIXED_ADDR },
        { "hardware",                           TOK_HARDWARE },
        { "ignore",                             TOK_IGNORE },
        { "initial-interval",                   TOK_INITIAL_INTERVAL },
        { "interface",                          TOK_INTERFACE },
        { "lease",                              TOK_LEASE },
        { "link-timeout",                       TOK_LINK_TIMEOUT },
        { "media",                              TOK_MEDIA },
        { "medium",                             TOK_MEDIUM },
        { "option",                             TOK_OPTION },
        { "prepend",                            TOK_PREPEND },
        { "rebind",                             TOK_REBIND },
        { "reboot",                             TOK_REBOOT },
        { "reject",                             TOK_REJECT },
        { "renew",                              TOK_RENEW },
        { "request",                            TOK_REQUEST },
        { "require",                            TOK_REQUIRE },
        { "retry",                              TOK_RETRY },
        { "script",                             TOK_SCRIPT },
        { "select-timeout",                     TOK_SELECT_TIMEOUT },
        { "send",                               TOK_SEND },
        { "server-name",                        TOK_SERVER_NAME },
        { "supersede",                          TOK_SUPERSEDE },
        { "timeout",                            TOK_TIMEOUT },
        { "token-ring",                         TOK_TOKEN_RING }
};

int
kw_cmp(const void *k, const void *e)
{
        return (strcasecmp(k, ((const struct keywords *)e)->k_name));
}

static int
intern(char *atom, int dfv)
{
        const struct keywords *p;

        p = bsearch(atom, keywords, sizeof(keywords)/sizeof(keywords[0]),
            sizeof(keywords[0]), kw_cmp);
        if (p)
                return (p->k_val);
        return (dfv);
}