OpenBSD-4.6/sbin/dhclient/parse.c
/* $OpenBSD: parse.c,v 1.18 2007/01/08 13:34:38 krw Exp $ */
/* Common parser code for dhcpd and dhclient. */
/*
* Copyright (c) 1995, 1996, 1997, 1998 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 "dhcpd.h"
#include "dhctoken.h"
/*
* Skip to the semicolon ending the current statement. If we encounter
* braces, the matching closing brace terminates the statement. If we
* encounter a right brace but haven't encountered a left brace, return
* leaving the brace in the token buffer for the caller. If we see a
* semicolon and haven't seen a left brace, return. This lets us skip
* over:
*
* statement;
* statement foo bar { }
* statement foo bar { statement { } }
* statement}
*
* ...et cetera.
*/
void
skip_to_semi(FILE *cfile)
{
int token;
char *val;
int brace_count = 0;
do {
token = peek_token(&val, cfile);
if (token == '}') {
if (brace_count) {
token = next_token(&val, cfile);
if (!--brace_count)
return;
} else
return;
} else if (token == '{') {
brace_count++;
} else if (token == ';' && !brace_count) {
token = next_token(&val, cfile);
return;
} else if (token == '\n') {
/*
* EOL only happens when parsing
* /etc/resolv.conf, and we treat it like a
* semicolon because the resolv.conf file is
* line-oriented.
*/
token = next_token(&val, cfile);
return;
}
token = next_token(&val, cfile);
} while (token != EOF);
}
int
parse_semi(FILE *cfile)
{
int token;
char *val;
token = next_token(&val, cfile);
if (token != ';') {
parse_warn("semicolon expected.");
skip_to_semi(cfile);
return (0);
}
return (1);
}
/*
* string-parameter :== STRING SEMI
*/
char *
parse_string(FILE *cfile)
{
char *val, *s;
int token;
token = next_token(&val, cfile);
if (token != TOK_STRING) {
parse_warn("filename must be a string");
skip_to_semi(cfile);
return (NULL);
}
s = malloc(strlen(val) + 1);
if (!s)
error("no memory for string %s.", val);
strlcpy(s, val, strlen(val) + 1);
if (!parse_semi(cfile)) {
free(s);
return (NULL);
}
return (s);
}
int
parse_ip_addr(FILE *cfile, struct iaddr *addr)
{
addr->len = 4;
return (parse_numeric_aggregate(cfile, addr->iabuf, addr->len, '.',
10));
}
/*
* hardware-parameter :== HARDWARE ETHERNET csns SEMI
* csns :== NUMBER | csns COLON NUMBER
*/
void
parse_hardware_param(FILE *cfile, struct hardware *hardware)
{
int token;
char *val;
token = next_token(&val, cfile);
switch (token) {
case TOK_ETHERNET:
hardware->htype = HTYPE_ETHER;
hardware->hlen = 6;
break;
case TOK_TOKEN_RING:
hardware->htype = HTYPE_IEEE802;
hardware->hlen = 6;
break;
case TOK_FDDI:
hardware->htype = HTYPE_FDDI;
hardware->hlen = 6;
break;
default:
parse_warn("expecting a network hardware type");
skip_to_semi(cfile);
return;
}
if (parse_numeric_aggregate(cfile, hardware->haddr, hardware->hlen,
':', 16) == 0)
return;
token = next_token(&val, cfile);
if (token != ';') {
parse_warn("expecting semicolon.");
skip_to_semi(cfile);
}
}
/*
* lease-time :== NUMBER SEMI
*/
void
parse_lease_time(FILE *cfile, time_t *timep)
{
char *val;
int token;
token = next_token(&val, cfile);
if (token != TOK_NUMBER) {
parse_warn("Expecting numeric lease time");
skip_to_semi(cfile);
return;
}
convert_num((unsigned char *)timep, val, 10, 32);
/* Unswap the number - convert_num returns stuff in NBO. */
*timep = ntohl(*timep); /* XXX */
parse_semi(cfile);
}
/*
* Parse a sequence of numbers separated by the token specified in separator.
* Exactly max numbers are expected.
*/
int
parse_numeric_aggregate(FILE *cfile, unsigned char *buf, int max, int separator,
int base)
{
char *val;
int token, count;
if (buf == NULL || max == 0)
error("no space for numeric aggregate");
for (count = 0; count < max; count++, buf++) {
if (count && (peek_token(&val, cfile) == separator))
token = next_token(&val, cfile);
token = next_token(&val, cfile);
if (token == TOK_NUMBER || (base == 16 && token == TOK_NUMBER_OR_NAME))
/* XXX Need to check if conversion was successful. */
convert_num(buf, val, base, 8);
else
break;
}
if (count < max) {
parse_warn("numeric aggregate too short.");
return (0);
}
return (1);
}
void
convert_num(unsigned char *buf, char *str, int base, int size)
{
int negative = 0, tval, max;
u_int32_t val = 0;
char *ptr = str;
if (*ptr == '-') {
negative = 1;
ptr++;
}
/* If base wasn't specified, figure it out from the data. */
if (!base) {
if (ptr[0] == '0') {
if (ptr[1] == 'x') {
base = 16;
ptr += 2;
} else if (isascii(ptr[1]) && isdigit(ptr[1])) {
base = 8;
ptr += 1;
} else
base = 10;
} else
base = 10;
}
do {
tval = *ptr++;
/* XXX assumes ASCII... */
if (tval >= 'a')
tval = tval - 'a' + 10;
else if (tval >= 'A')
tval = tval - 'A' + 10;
else if (tval >= '0')
tval -= '0';
else {
warning("Bogus number: %s.", str);
break;
}
if (tval >= base) {
warning("Bogus number: %s: digit %d not in base %d",
str, tval, base);
break;
}
val = val * base + tval;
} while (*ptr);
if (negative)
max = (1 << (size - 1));
else
max = (1 << (size - 1)) + ((1 << (size - 1)) - 1);
if (val > max) {
switch (base) {
case 8:
warning("value %s%o exceeds max (%d) for precision.",
negative ? "-" : "", val, max);
break;
case 16:
warning("value %s%x exceeds max (%d) for precision.",
negative ? "-" : "", val, max);
break;
default:
warning("value %s%u exceeds max (%d) for precision.",
negative ? "-" : "", val, max);
break;
}
}
if (negative)
switch (size) {
case 8:
*buf = -(unsigned long)val;
break;
case 16:
putShort(buf, -(unsigned long)val);
break;
case 32:
putLong(buf, -(unsigned long)val);
break;
default:
warning("Unexpected integer size: %d", size);
break;
}
else
switch (size) {
case 8:
*buf = (u_int8_t)val;
break;
case 16:
putUShort(buf, (u_int16_t)val);
break;
case 32:
putULong(buf, val);
break;
default:
warning("Unexpected integer size: %d", size);
break;
}
}
/*
* date :== NUMBER NUMBER SLASH NUMBER SLASH NUMBER
* NUMBER COLON NUMBER COLON NUMBER SEMI
*
* Dates are always in GMT; first number is day of week; next is
* year/month/day; next is hours:minutes:seconds on a 24-hour
* clock.
*/
time_t
parse_date(FILE *cfile)
{
static int months[11] = { 31, 59, 90, 120, 151, 181,
212, 243, 273, 304, 334 };
int guess, token;
struct tm tm;
char *val;
/* Day of week... */
token = next_token(&val, cfile);
if (token != TOK_NUMBER) {
parse_warn("numeric day of week expected.");
if (token != ';')
skip_to_semi(cfile);
return (0);
}
tm.tm_wday = atoi(val);
/* Year... */
token = next_token(&val, cfile);
if (token != TOK_NUMBER) {
parse_warn("numeric year expected.");
if (token != ';')
skip_to_semi(cfile);
return (0);
}
tm.tm_year = atoi(val);
if (tm.tm_year > 1900)
tm.tm_year -= 1900;
/* Slash separating year from month... */
token = next_token(&val, cfile);
if (token != '/') {
parse_warn("expected slash separating year from month.");
if (token != ';')
skip_to_semi(cfile);
return (0);
}
/* Month... */
token = next_token(&val, cfile);
if (token != TOK_NUMBER) {
parse_warn("numeric month expected.");
if (token != ';')
skip_to_semi(cfile);
return (0);
}
tm.tm_mon = atoi(val) - 1;
/* Slash separating month from day... */
token = next_token(&val, cfile);
if (token != '/') {
parse_warn("expected slash separating month from day.");
if (token != ';')
skip_to_semi(cfile);
return (0);
}
/* Day... */
token = next_token(&val, cfile);
if (token != TOK_NUMBER) {
parse_warn("numeric day of month expected.");
if (token != ';')
skip_to_semi(cfile);
return (0);
}
tm.tm_mday = atoi(val);
/* Hour... */
token = next_token(&val, cfile);
if (token != TOK_NUMBER) {
parse_warn("numeric hour expected.");
if (token != ';')
skip_to_semi(cfile);
return (0);
}
tm.tm_hour = atoi(val);
/* Colon separating hour from minute... */
token = next_token(&val, cfile);
if (token != ':') {
parse_warn("expected colon separating hour from minute.");
if (token != ';')
skip_to_semi(cfile);
return (0);
}
/* Minute... */
token = next_token(&val, cfile);
if (token != TOK_NUMBER) {
parse_warn("numeric minute expected.");
if (token != ';')
skip_to_semi(cfile);
return (0);
}
tm.tm_min = atoi(val);
/* Colon separating minute from second... */
token = next_token(&val, cfile);
if (token != ':') {
parse_warn("expected colon separating minute from second.");
if (token != ';')
skip_to_semi(cfile);
return (0);
}
/* Second... */
token = next_token(&val, cfile);
if (token != TOK_NUMBER) {
parse_warn("numeric second expected.");
if (token != ';')
skip_to_semi(cfile);
return (0);
}
tm.tm_sec = atoi(val);
tm.tm_isdst = 0;
/* XXX: We assume that mktime does not use tm_yday. */
tm.tm_yday = 0;
/* Make sure the date ends in a semicolon... */
token = next_token(&val, cfile);
if (token != ';') {
parse_warn("semicolon expected.");
skip_to_semi(cfile);
return (0);
}
/* Guess the time value... */
guess = ((((((365 * (tm.tm_year - 70) + /* Days in years since '70 */
(tm.tm_year - 69) / 4 + /* Leap days since '70 */
(tm.tm_mon /* Days in months this year */
? months[tm.tm_mon - 1] : 0) +
(tm.tm_mon > 1 && /* Leap day this year */
!((tm.tm_year - 72) & 3)) +
tm.tm_mday - 1) * 24) + /* Day of month */
tm.tm_hour) * 60) + tm.tm_min) * 60) + tm.tm_sec;
/*
* This guess could be wrong because of leap seconds or other
* weirdness we don't know about that the system does. For
* now, we're just going to accept the guess, but at some point
* it might be nice to do a successive approximation here to get
* an exact value. Even if the error is small, if the server
* is restarted frequently (and thus the lease database is
* reread), the error could accumulate into something
* significant.
*/
return (guess);
}