OpenBSD-4.6/usr.sbin/dhcpd/parse.c
/* $OpenBSD: parse.c,v 1.11 2007/02/26 00:49:53 stevesk 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);
}
/*
* hostname :== identifier | hostname DOT identifier
*/
char *
parse_host_name(FILE *cfile)
{
char *val, *s, *t;
int token, len = 0;
pair c = NULL;
/* Read a dotted hostname... */
do {
/* Read a token, which should be an identifier. */
token = next_token(&val, cfile);
if (!is_identifier(token) && token != TOK_NUMBER) {
parse_warn("expecting an identifier in hostname");
skip_to_semi(cfile);
return (NULL);
}
/* Store this identifier... */
if (!(s = malloc(strlen(val) + 1)))
error("can't allocate temp space for hostname.");
strlcpy(s, val, strlen(val) + 1);
c = cons((caddr_t) s, c);
len += strlen(s) + 1;
/*
* Look for a dot; if it's there, keep going, otherwise
* we're done.
*/
token = peek_token(&val, cfile);
if (token == '.')
token = next_token(&val, cfile);
} while (token == '.');
/* Assemble the hostname together into a string. */
if (!(s = malloc(len)))
error("can't allocate space for hostname.");
t = s + len;
*--t = '\0';
while (c) {
pair cdr = c->cdr;
int l = strlen((char *)c->car);
t -= l;
memcpy(t, (char *)c->car, l);
/* Free up temp space. */
free(c->car);
free(c);
c = cdr;
if (t != s)
*--t = '.';
}
return (s);
}
/*
* hardware-parameter :== HARDWARE ETHERNET csns SEMI
* csns :== NUMBER | csns COLON NUMBER
*/
void
parse_hardware_param(FILE *cfile, struct hardware *hardware)
{
char *val;
int token, hlen;
unsigned char *t;
token = next_token(&val, cfile);
switch (token) {
case TOK_ETHERNET:
hardware->htype = HTYPE_ETHER;
break;
case TOK_TOKEN_RING:
hardware->htype = HTYPE_IEEE802;
break;
case TOK_FDDI:
hardware->htype = HTYPE_FDDI;
break;
default:
parse_warn("expecting a network hardware type");
skip_to_semi(cfile);
return;
}
/*
* Parse the hardware address information. Technically, it
* would make a lot of sense to restrict the length of the data
* we'll accept here to the length of a particular hardware
* address type. Unfortunately, there are some broken clients
* out there that put bogus data in the chaddr buffer, and we
* accept that data in the lease file rather than simply failing
* on such clients. Yuck.
*/
hlen = 0;
t = parse_numeric_aggregate(cfile, NULL, &hlen, ':', 16, 8);
if (!t)
return;
if (hlen > sizeof(hardware->haddr)) {
free(t);
parse_warn("hardware address too long");
} else {
hardware->hlen = hlen;
memcpy((unsigned char *)&hardware->haddr[0], t, hardware->hlen);
if (hlen < sizeof(hardware->haddr))
memset(&hardware->haddr[hlen], 0,
sizeof(hardware->haddr) - hlen);
free(t);
}
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);
}
/*
* No BNF for numeric aggregates - that's defined by the caller. What
* this function does is to parse a sequence of numbers separated by the
* token specified in separator. If max is zero, any number of numbers
* will be parsed; otherwise, exactly max numbers are expected. Base
* and size tell us how to internalize the numbers once they've been
* tokenized.
*/
unsigned char *
parse_numeric_aggregate(FILE *cfile, unsigned char *buf, int *max,
int separator, int base, int size)
{
char *val, *t;
int token, count = 0;
unsigned char *bufp = buf, *s = NULL;
pair c = NULL;
if (!bufp && *max) {
bufp = malloc(*max * size / 8);
if (!bufp)
error("can't allocate space for numeric aggregate");
} else
s = bufp;
do {
if (count) {
token = peek_token(&val, cfile);
if (token != separator) {
if (!*max)
break;
if (token != '{' && token != '}')
token = next_token(&val, cfile);
parse_warn("too few numbers.");
if (token != ';')
skip_to_semi(cfile);
return (NULL);
}
token = next_token(&val, cfile);
}
token = next_token(&val, cfile);
if (token == EOF) {
parse_warn("unexpected end of file");
break;
}
/* Allow NUMBER_OR_NAME if base is 16. */
if (token != TOK_NUMBER &&
(base != 16 || token != TOK_NUMBER_OR_NAME)) {
parse_warn("expecting numeric value.");
skip_to_semi(cfile);
return (NULL);
}
/*
* If we can, convert the number now; otherwise, build a
* linked list of all the numbers.
*/
if (s) {
convert_num(s, val, base, size);
s += size / 8;
} else {
t = malloc(strlen(val) + 1);
if (!t)
error("no temp space for number.");
strlcpy(t, val, strlen(val) + 1);
c = cons(t, c);
}
} while (++count != *max);
/* If we had to cons up a list, convert it now. */
if (c) {
bufp = malloc(count * size / 8);
if (!bufp)
error("can't allocate space for numeric aggregate.");
s = bufp + count - size / 8;
*max = count;
}
while (c) {
pair cdr = c->cdr;
convert_num(s, (char *)c->car, base, size);
s -= size / 8;
/* Free up temp space. */
free(c->car);
free(c);
c = cdr;
}
return (bufp);
}
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);
}