unrealircd/src/badwords.c

/*
 *   IRC - Internet Relay Chat, badwords.c
 *   Copyleft (C) 2000 meow <csi@gnu.net>
 * 
 *   Provides functions, for loading and filtering unwanted words out of
 *   a string, or in this case part of a message.  Please note that this
 *   is flawed because when mode_strip is set, mode_stripbadwords is not
 *   active.  This is due to the structure of m_message(), and therefore
 *   will not change until I (or someone else) revamps the code.
 *
 *   You can redistribute and/or modify this under the terms of the GNU
 *   General Public License as published by the Free Software Foundation.
 *
 *   Disclaimer: You have no rights.  Use at your own risk.  Don't drink
 *   too much pepsi.
 */

#ifndef _WIN32
#include <unistd.h>
#endif
#include "config.h"
#include "struct.h"
#include "common.h"
#include "h.h"
#ifdef STRIPBADWORDS
#include "badwords.h"

/* This was modified a bit in order to use newconf. The loading functions
 * have been trashed and integrated into the config parser. The striping
 * function now only uses REPLACEWORD if no word is specifically defined
 * for the word found. Also the freeing function has been ditched. -- codemastr
 */

#ifdef FAST_BADWORD_REPLACE
/*
 * our own strcasestr implementation because strcasestr is often not
 * available or is not working correctly (??).
 */
char *our_strcasestr(char *haystack, char *needle) {
int i;
int nlength = strlen (needle);
int hlength = strlen (haystack);

	if (nlength > hlength) return NULL;
	if (hlength <= 0) return NULL;
	if (nlength <= 0) return haystack;
	for (i = 0; i <= (hlength - nlength); i++) {
		if (strncasecmp (haystack + i, needle, nlength) == 0)
			return haystack + i;
	}
  return NULL; /* not found */
}
inline int fast_badword_match(ConfigItem_badword *badword, char *line)
{
 	char *p;
	int bwlen = strlen(badword->word);
	if ((badword->type & BADW_TYPE_FAST_L) && (badword->type & BADW_TYPE_FAST_R))
		return (our_strcasestr(line, badword->word) ? 1 : 0);

	p = line;
	while((p = our_strcasestr(p, badword->word)))
	{
		if (!(badword->type & BADW_TYPE_FAST_L))
		{
			if ((p != line) && isalnum(*(p - 1))) /* aaBLA but no *BLA */
				goto next;
		}
		if (!(badword->type & BADW_TYPE_FAST_R))
		{
			if (isalnum(*(p + bwlen)))  /* BLAaa but no BLA* */
				goto next;
		}
		/* Looks like it matched */
		return 1;
next:
		p += bwlen;
	}
	return 0;
}
/* fast_badword_replace:
 * a fast replace routine written by Syzop used for replacing badwords.
 * searches in line for huntw and replaces it with replacew,
 * buf is used for the result and max is sizeof(buf).
 * (Internal assumptions: max > 0 AND max > strlen(line)+1)
 */
inline int fast_badword_replace(ConfigItem_badword *badword, char *line, char *buf, int max)
{
/* Some aliases ;P */
char *replacew = badword->replace ? badword->replace : REPLACEWORD;
char *pold = line, *pnew = buf; /* Pointers to old string and new string */
char *poldx = line;
int replacen = -1; /* Only calculated if needed. w00t! saves us a few nanosecs? lol */
int searchn = -1;
char *startw, *endw;
char *c_eol = buf + max - 1; /* Cached end of (new) line */
int run = 1;
int cleaned = 0;

	Debug((DEBUG_NOTICE, "replacing %s -> %s in '%s'", badword->word, replacew, line));

	while(run) {
		pold = our_strcasestr(pold, badword->word);
		if (!pold)
			break;
		cleaned = 1;
		if (replacen == -1)
			replacen = strlen(replacew);
		if (searchn == -1)
			searchn = strlen(badword->word);
		/* Hunt for start of word */
 		if (pold > line) {
			for (startw = pold; (isalnum(*startw) && (startw != line)); startw--);
			if (!isalnum(*startw))
				startw++; /* Don't point at the space/seperator but at the word! */
		} else {
			startw = pold;
		}

		if (!(badword->type & BADW_TYPE_FAST_L) && (pold != startw)) {
			/* not matched */
			pold++;
			continue;
		}

		/* Hunt for end of word */
		for (endw = pold; ((*endw != '\0') && (isalnum(*endw))); endw++);

		if (!(badword->type & BADW_TYPE_FAST_R) && (pold+searchn != endw)) {
			/* not matched */
			pold++;
			continue;
		}

		/* Do we have any not-copied-yet data? */
		if (poldx != startw) {
			int tmp_n = startw - poldx;
			if (pnew + tmp_n >= c_eol) {
				/* Partial copy and return... */
				memcpy(pnew, poldx, c_eol - pnew);
				*c_eol = '\0';
				return 1;
			}

			memcpy(pnew, poldx, tmp_n);
			pnew += tmp_n;
		}
		/* Now update the word in buf (pnew is now something like startw-in-new-buffer */

		if (replacen) {
			if ((pnew + replacen) >= c_eol) {
				/* Partial copy and return... */
				memcpy(pnew, replacew, c_eol - pnew);
				*c_eol = '\0';
				return 1;
			}
			memcpy(pnew, replacew, replacen);
			pnew += replacen;
		}
		poldx = pold = endw;
	}
	/* Copy the last part */
	if (*poldx) {
		strncpy(pnew, poldx, c_eol - pnew);
		*(c_eol) = '\0';
	} else {
		*pnew = '\0';
	}
	return cleaned;
}
#endif

/*
 * Returns a string, which has been filtered by the words loaded via
 * the loadbadwords() function.  It's primary use is to filter swearing
 * in both private and public messages
 */

void badwords_stats(aClient *sptr)
{
}

char *stripbadwords(char *str, ConfigItem_badword *start_bw, int *blocked)
{
	regmatch_t pmatch[MAX_MATCH];
	static char cleanstr[4096];
	char buf[4096];
	char *ptr;
	int  matchlen, m, stringlen, cleaned;
	ConfigItem_badword *this_word;
	
	*blocked = 0;

	if (!start_bw)
		return str;

	/*
	 * work on a copy
	 */
	stringlen = strlcpy(cleanstr, StripControlCodes(str), sizeof cleanstr);
	memset(&pmatch, 0, sizeof pmatch);
	matchlen = 0;
	buf[0] = '\0';
	cleaned = 0;

	for (this_word = start_bw; this_word; this_word = (ConfigItem_badword *)this_word->next)
	{
#ifdef FAST_BADWORD_REPLACE
		if (this_word->type & BADW_TYPE_FAST)
		{
			if (this_word->action == BADWORD_BLOCK)
			{
				if (fast_badword_match(this_word, cleanstr))
				{
					*blocked = 1;
					return NULL;
				}
			}
			else
			{
				int n;
				/* fast_badword_replace() does size checking so we can use 512 here instead of 4096 */
				n = fast_badword_replace(this_word, cleanstr, buf, 512);
				if (!cleaned && n)
					cleaned = n;
				strcpy(cleanstr, buf);
				memset(buf, 0, sizeof(buf)); /* regexp likes this somehow */
			}
		} else
		if (this_word->type & BADW_TYPE_REGEX)
		{
#endif
			if (this_word->action == BADWORD_BLOCK)
			{
				if (!regexec(&this_word->expr, cleanstr, 0, NULL, 0))
				{
					*blocked = 1;
					return NULL;
				}
			}
			else
			{
				ptr = cleanstr; /* set pointer to start of string */
				while (regexec(&this_word->expr, ptr, MAX_MATCH, pmatch,0) != REG_NOMATCH)
				{
					if (pmatch[0].rm_so == -1)
						break;
					m = pmatch[0].rm_eo - pmatch[0].rm_so;
					if (m == 0)
						break; /* anti-loop */
					cleaned = 1;
					matchlen += m;
					strlncat(buf, ptr, sizeof buf, pmatch[0].rm_so);
					if (this_word->replace)
						strlcat(buf, this_word->replace, sizeof buf); 
					else
						strlcat(buf, REPLACEWORD, sizeof buf);
					ptr += pmatch[0].rm_eo;	/* Set pointer after the match pos */
					memset(&pmatch, 0, sizeof(pmatch));
				}

				/* All the better to eat you with! */
				strlcat(buf, ptr, sizeof buf);	
				memcpy(cleanstr, buf, sizeof cleanstr);
				memset(buf, 0, sizeof(buf));
				if (matchlen == stringlen)
					break;
			}
#ifdef FAST_BADWORD_REPLACE
		}
#endif
	}

	cleanstr[511] = '\0'; /* cutoff, just to be sure */

	return (cleaned) ? cleanstr : str;
}

char inline *stripbadwords_channel(char *str, int *blocked)
{
	return stripbadwords(str, conf_badword_channel, blocked);
}

char inline *stripbadwords_message(char *str, int *blocked)
{
	return stripbadwords(str, conf_badword_message, blocked);
}
char inline *stripbadwords_quit(char *str, int *blocked)
{
	return stripbadwords(str, conf_badword_quit, blocked);
}

#endif