path: root/epan/dtd_preparse.l

%top {
/* Include this before everything else, for various large-file definitions */
#include "config.h"
#include <wireshark.h>
}

/*
 * We want a reentrant scanner.
 */
%option reentrant

/*
 * We don't use input, so don't generate code for it.
 */
%option noinput

/*
 * We don't use unput, so don't generate code for it.
 */
%option nounput

/*
 * We don't read interactively from the terminal.
 */
%option never-interactive

/*
 * We want to stop processing when we get to the end of the input.
 */
%option noyywrap

/*
 * The type for the state we keep for a scanner.
 */
%option extra-type="Dtd_PreParse_scanner_state_t *"

/*
 * The language we're scanning is case-insensitive.
 */
%option caseless

/*
 * Prefix scanner routines with "Dtd_PreParse_" rather than "yy", so this
 * scanner can coexist with other scanners.
 */
%option prefix="Dtd_PreParse_"

%option outfile="dtd_preparse.c"

/*
 * We have to override the memory allocators so that we don't get
 * "unused argument" warnings from the yyscanner argument (which
 * we don't use, as we have a global memory allocator).
 *
 * We provide, as macros, our own versions of the routines generated by Flex,
 * which just call malloc()/realloc()/free() (as the Flex versions do),
 * discarding the extra argument.
 */
%option noyyalloc
%option noyyrealloc
%option noyyfree

%{
	/*
	 * dtd_preparse.l
	 *
	 * an XML dissector for wireshark
	 *
	 * DTD Preparser -  import a dtd file into a GString
	 *		    including files, removing comments
	 *                  and resolving %entities;
	 *
	 * Copyright 2004, Luis E. Garcia Ontanon <luis@ontanon.org>
	 *
	 * Wireshark - Network traffic analyzer
	 * By Gerald Combs <gerald@wireshark.org>
	 * Copyright 1998 Gerald Combs
	 *
	 * This program is free software; you can redistribute it and/or
	 * modify it under the terms of the GNU General Public License
	 * as published by the Free Software Foundation; either version 2
	 * of the License, or (at your option) any later version.
	 *
	 * This program is distributed in the hope that it will be useful,
	 * but WITHOUT ANY WARRANTY; without even the implied warranty of
	 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	 * GNU General Public License for more details.
	 *
	 * You should have received a copy of the GNU General Public License
	 * along with this program; if not, write to the Free Software
	 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
	 */

#include <glib.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include "dtd.h"
#include <wsutil/file_util.h>

/*
 * Disable diagnostics in the code generated by Flex.
 */
DIAG_OFF_FLEX()

#define ECHO g_string_append(yyextra->current,yytext);

struct _dtd_preparse_scanner_state {
	const char* dtd_dirname;
	const char* filename;
	unsigned linenum;

	GString* error;

	GHashTable* entities;
	GString* current;
	GString* output;
	char* entity_name;
};

static const char* replace_entity(Dtd_PreParse_scanner_state_t* state, char* s);

#define YY_USER_INIT { \
	BEGIN OUTSIDE; \
}

/*
 * Flex (v 2.5.35) uses this symbol to "exclude" unistd.h
 */
#ifdef _WIN32
#define YY_NO_UNISTD_H
#endif

/*
 * Sleazy hack to suppress compiler warnings in yy_fatal_error().
 */
#define YY_EXIT_FAILURE ((void)yyscanner, 2)

/*
 * Macros for the allocators, to discard the extra argument.
 */
#define Dtd_PreParse_alloc(size, yyscanner)		(void *)malloc(size)
#define Dtd_PreParse_realloc(ptr, size, yyscanner)	(void *)realloc((char *)(ptr), (size))
#define Dtd_PreParse_free(ptr, yyscanner)		free((char *)ptr)

%}
xmlpi_start "<?"
xmlpi_stop  "?>"
xmlpi_chars .

comment_start "<!--"
comment_stop "-->"
special_start "<!"
special_stop ">"

entity_start     "<!"[[:blank:]\n]*entity[[:blank:]\n]*"%"
system     SYSTEM
filename   [^"]+


name [A-Za-z][-:A-Za-z0-9_\.]*

quote "\""
percent [%]
escaped_quote "\\\""
non_quote [^"%]+

avoid_editor_bug ["]

entity        [%&][A-Za-z][-A-Za-z0-9_]*;

whitespace [[blank:]]+
newline    \n
%START OUTSIDE IN_COMMENT IN_ENTITY NAMED_ENTITY IN_QUOTE ENTITY_DONE XMLPI
%%


{entity}				if (yyextra->current) g_string_append_printf(yyextra->current,"%s\n%s\n",replace_entity(yyextra, yytext),dtd_location(yyextra));

{whitespace}				if (yyextra->current) g_string_append(yyextra->current," ");

<OUTSIDE>{xmlpi_start}			{ g_string_append(yyextra->current,yytext); BEGIN XMLPI; }
<XMLPI>{xmlpi_chars}			{ g_string_append(yyextra->current,yytext); }
<XMLPI>{newline}			{ g_string_append(yyextra->current,yytext); }
<XMLPI>{xmlpi_stop}			{ g_string_append(yyextra->current,yytext); BEGIN OUTSIDE; }

<OUTSIDE>{comment_start}		{ yyextra->current = NULL; BEGIN IN_COMMENT; }
<IN_COMMENT>[^-]?			|
<IN_COMMENT>[-]				;
<IN_COMMENT>{comment_stop}		{ yyextra->current = yyextra->output; BEGIN OUTSIDE; }

{newline}				{
	yyextra->linenum++;
	if (yyextra->current) g_string_append_printf(yyextra->current,"%s\n",dtd_location(yyextra));
}


<OUTSIDE>{entity_start}			{ BEGIN IN_ENTITY; }
<IN_ENTITY>{name}			{ yyextra->entity_name = ws_strdup_printf("%%%s;",yytext); BEGIN NAMED_ENTITY; }
<NAMED_ENTITY>{quote}			{ yyextra->current = g_string_new(dtd_location(yyextra)); BEGIN IN_QUOTE; }
<IN_QUOTE>{quote}			{ g_hash_table_insert(yyextra->entities,yyextra->entity_name,yyextra->current);  BEGIN ENTITY_DONE; }
<IN_QUOTE>{percent}			|
<IN_QUOTE>{non_quote}			|
<IN_QUOTE>{escaped_quote}		g_string_append(yyextra->current,yytext);
<NAMED_ENTITY>{system}			{
	g_string_append_printf(yyextra->error,"at %s:%u: file inclusion is not supported!", yyextra->filename, yyextra->linenum);
	yyterminate();
}
<ENTITY_DONE>{special_stop}		{ yyextra->current = yyextra->output; g_string_append(yyextra->current,"\n"); BEGIN OUTSIDE; }

%%

/*
 * Turn diagnostics back on, so we check the code that we've written.
 */
DIAG_ON_FLEX()

static const char* replace_entity(Dtd_PreParse_scanner_state_t* state, char* entity) {
	GString* replacement;

	*entity = '%';

	replacement = (GString*)g_hash_table_lookup(state->entities,entity);

	if (replacement) {
		return replacement->str;
	} else {
		g_string_append_printf(state->error,"dtd_preparse: in file '%s': entity %s does not exists\n", state->filename, entity);
		return "";
	}

}

const char* dtd_location(Dtd_PreParse_scanner_state_t* state) {
	static char* loc = NULL;

	g_free(loc);

	if (!state) return NULL;

	loc = ws_strdup_printf("<? wireshark:location %s:%u ?>", state->filename, state->linenum);

	return loc;
}

static gboolean free_gstring_hash_items(void *k,void *v,void *p _U_) {
	g_free(k);
	g_string_free((GString*)v,true);
	return true;
}

extern GString* dtd_preparse(const char* dname,const  char* fname, GString* err) {
	char* fullname = ws_strdup_printf("%s%c%s",dname,G_DIR_SEPARATOR,fname);
	FILE *in;
	yyscan_t scanner;
	Dtd_PreParse_scanner_state_t state;

	in = ws_fopen(fullname,"r");

	if (!in) {
		if (err)
			g_string_append_printf(err, "Could not open file: '%s', error: %s",fullname,g_strerror(errno));
		g_free(fullname);
		return NULL;
	}

	if (Dtd_PreParse_lex_init(&scanner) != 0) {
		if (err)
			g_string_append_printf(err, "Can't initialize scanner: %s",
			    strerror(errno));
		fclose(in);
		g_free(fullname);
		return NULL;
	}

	Dtd_PreParse_set_in(in, scanner);

	state.dtd_dirname = dname;
	state.filename = fname;
	state.linenum = 1;

	state.error = err;

	state.entities = g_hash_table_new(g_str_hash,g_str_equal);
	state.current = state.output = g_string_new(dtd_location(&state));
	state.entity_name = NULL;

	/* Associate the state with the scanner */
	Dtd_PreParse_set_extra(&state, scanner);

	Dtd_PreParse_lex(scanner);

	Dtd_PreParse_lex_destroy(scanner);
	fclose(in);

	g_hash_table_foreach_remove(state.entities,free_gstring_hash_items,NULL);
	g_hash_table_destroy(state.entities);

	g_free(fullname);

	return state.output;
}