asterisk/main/ast_expr2.fl

%{
/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2006, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief Dialplan Expression Lexical Scanner
 */

#include <sys/types.h>
#include <stdio.h>

#if defined(STANDALONE)
#ifndef __USE_ISOC99
#define __USE_ISOC99 1
#endif
#endif

#ifdef __USE_ISOC99
#define FP___PRINTF "%.18Lg"
#define FP___FMOD   fmodl
#define FP___STRTOD  strtold
#define FP___TYPE    long double
#else
#define FP___PRINTF "%.16g"
#define FP___FMOD   fmod
#define FP___STRTOD  strtod
#define FP___TYPE    double
#endif

#include <stdlib.h>
#include <string.h>
#include <locale.h>
#include <ctype.h>
#if !defined(SOLARIS) && !defined(__CYGWIN__)
/* #include <err.h> */
#else
#define quad_t int64_t
#endif
#include <errno.h>
#include <regex.h>
#include <limits.h>

#include "asterisk/ast_expr.h"
#include "asterisk/logger.h"
#ifndef STANDALONE
#include "asterisk/strings.h"
#include "asterisk/channel.h"
#endif

/* Conditionally redefine the macro from flex 2.5.35, in case someone uses flex <2.5.35 to regenerate this file. */
#ifndef ECHO
#define ECHO do { if (fwrite( yytext, yyleng, 1, yyout )) {} } while (0)
#endif

enum valtype {
	AST_EXPR_number, AST_EXPR_numeric_string, AST_EXPR_string
} ;

struct val {
	enum valtype type;
	union {
		char *s;
		FP___TYPE i; /* long double or just double if it's a bad day */
	} u;
} ;

#include "ast_expr2.h" /* the o/p of the bison on ast_expr2.y */

#define SET_COLUMNS	do {		\
	yylloc_param->first_column = (int)(yyg->yytext_r - YY_CURRENT_BUFFER_LVALUE->yy_ch_buf); \
	yylloc_param->last_column += yyleng - 1; \
	yylloc_param->first_line = yylloc_param->last_line = 1; \
	} while (0)

#define SET_STRING	do {		\
	yylval_param->val = calloc(1, sizeof(struct val));	\
	yylval_param->val->type = AST_EXPR_string;		\
	yylval_param->val->u.s = strdup(yytext);		\
	} while (0)

#define SET_NUMERIC_STRING	do {	\
	yylval_param->val = calloc(1, sizeof(struct val));	\
	yylval_param->val->type = AST_EXPR_numeric_string;	\
	yylval_param->val->u.s = strdup(yytext);	\
	} while (0)

struct parse_io
{
	char *string;
	struct val *val;
	yyscan_t scanner;
	struct ast_channel *chan;
};
 
void ast_yyset_column(int column_no, yyscan_t yyscanner);
int ast_yyget_column(yyscan_t yyscanner);
static int curlycount = 0;
static char *expr2_token_subst(const char *mess);
%}

%option prefix="ast_yy"
%option batch
%option 8bit
%option outfile="ast_expr2f.c"
%option reentrant
%option bison-bridge
%option bison-locations
%option noyywrap
%option noyyfree
%x var trail

%%

\|	{ SET_COLUMNS; SET_STRING; return TOK_OR;}
\&	{ SET_COLUMNS; SET_STRING; return TOK_AND;}
\=	{ SET_COLUMNS; SET_STRING; return TOK_EQ;}
\|\|	{ SET_COLUMNS; SET_STRING; return TOK_OR;}
\&\&	{ SET_COLUMNS; SET_STRING; return TOK_AND;}
\=\=	{ SET_COLUMNS; SET_STRING; return TOK_EQ;}
\=~	{ SET_COLUMNS; SET_STRING; return TOK_EQTILDE;}
\~~	{ SET_COLUMNS; SET_STRING; return TOK_TILDETILDE;}
\>	{ SET_COLUMNS; SET_STRING; return TOK_GT;}
\<	{ SET_COLUMNS; SET_STRING; return TOK_LT;}
\>\=	{ SET_COLUMNS; SET_STRING; return TOK_GE;}
\<\=	{ SET_COLUMNS; SET_STRING; return TOK_LE;}
\!\=	{ SET_COLUMNS; SET_STRING; return TOK_NE;}
\+	{ SET_COLUMNS; SET_STRING; return TOK_PLUS;}
\,	{ SET_COLUMNS; SET_STRING; return TOK_COMMA;}
\-	{ SET_COLUMNS; SET_STRING; return TOK_MINUS;}
\*	{ SET_COLUMNS; SET_STRING; return TOK_MULT;}
\/	{ SET_COLUMNS; SET_STRING; return TOK_DIV;}
\%	{ SET_COLUMNS; SET_STRING; return TOK_MOD;}
\?	{ SET_COLUMNS; SET_STRING; return TOK_COND;}
\!	{ SET_COLUMNS; SET_STRING; return TOK_COMPL;}
\:	{ SET_COLUMNS; SET_STRING; return TOK_COLON;}
\:\:	{ SET_COLUMNS; SET_STRING; return TOK_COLONCOLON;}
\(	{ SET_COLUMNS; SET_STRING; return TOK_LP;}
\)	{ SET_COLUMNS; SET_STRING; return TOK_RP;}
\$\{	{
		/* gather the contents of ${} expressions, with trailing stuff,
		 * into a single TOKEN.
		 * They are much more complex now than they used to be
		 */
		curlycount = 0;
		BEGIN(var);
		yymore();
	}

[ \t\r]		{}
\"[^"]*\"	{SET_COLUMNS; SET_STRING; return TOKEN;}

[\n]		{/* what to do with eol */}
[0-9]+(\.[0-9]+)?		{
		SET_COLUMNS;
		/* the original behavior of the expression parser was
		 * to bring in numbers as a numeric string
		 */
		SET_NUMERIC_STRING;
		return TOKEN;
	}

([a-zA-Z0-9\.';\\_^#@]|[\x80-\xff]|($[^{]))+   {
		SET_COLUMNS;
		SET_STRING;
		return TOKEN;
	}

([a-zA-Z0-9\.';\\_^#@]|[\x80-\xff]|($[^{]))+\$\{	{
		curlycount = 0;
		BEGIN(var);
		yymore();
	}

<var>[^{}]*\}	{
		curlycount--;
		if (curlycount < 0) {
			BEGIN(trail);
			yymore();
		} else {
			yymore();
		}
	}
	
<var>[^{}]*\{	{
		curlycount++;
		yymore();
	}
	

<trail>[^-\t\r \n$():?%/+=*<>!|&]*	{
		BEGIN(0);
		SET_COLUMNS;
		SET_STRING;
		return TOKEN;
	}
	
<trail>[^-\t\r \n$():?%/+=*<>!|&]*\$\{	{
		curlycount = 0;
		BEGIN(var);
		yymore();
	}
	
<trail>[-\t\r \n$():?%/+=*<>!|&]	{
		char c = yytext[yyleng-1];
		BEGIN(0);
		unput(c);
		SET_COLUMNS;
		SET_STRING;
		return TOKEN;
	}
	
<trail><<EOF>>	{
		BEGIN(0);
		SET_COLUMNS;
		SET_STRING;
		return TOKEN;
		/*actually, if an expr is only a variable ref, this could happen a LOT */
	}

%%

/* I'm putting the interface routine to the whole parse here in the flexer input file
   mainly because of all the flexer initialization that has to be done. Shouldn't matter
   where it is, as long as it's somewhere. I didn't want to define a prototype for the
   ast_yy_scan_string in the .y file, because then, I'd have to define YY_BUFFER_STATE there...
	UGH! that would be inappropriate. */

int ast_yyparse(void *); /* need to/should define this prototype for the call to yyparse */
int ast_yyerror(const char *, YYLTYPE *, struct parse_io *); /* likewise */

void ast_yyfree(void *ptr, yyscan_t yyscanner)
{
    /* the normal generated yyfree func just frees its first arg;
     this get complaints on some systems, as sometimes this
     arg is a nil ptr! It's usually not fatal, but is irritating! */
	free( (char *) ptr );
}

int ast_expr(char *expr, char *buf, int length, struct ast_channel *chan)
{
	struct parse_io io = { .string = expr, .chan = chan };
	int return_value = 0;

	ast_yylex_init(&io.scanner);

	ast_yy_scan_string(expr, io.scanner);

	ast_yyparse ((void *) &io);

	ast_yylex_destroy(io.scanner);

	if (!io.val) {
		if (length > 1) {
			strcpy(buf, "0");
			return_value = 1;
		}
	} else {
		if (io.val->type == AST_EXPR_number) {
			int res_length;

			res_length = snprintf(buf, length, FP___PRINTF, io.val->u.i);
			return_value = (res_length <= length) ? res_length : length;
		} else {
			if (io.val->u.s)
#if defined(STANDALONE) || defined(LOW_MEMORY) || defined(STANDALONE)
				strncpy(buf, io.val->u.s, length - 1);
#else /* !STANDALONE && !LOW_MEMORY */
				ast_copy_string(buf, io.val->u.s, length);
#endif /* STANDALONE || LOW_MEMORY */
			else
				buf[0] = 0;
			return_value = strlen(buf);
			free(io.val->u.s);
		}
		free(io.val);
	}
	return return_value;
}

#ifndef STANDALONE
int ast_str_expr(struct ast_str **str, ssize_t maxlen, struct ast_channel *chan, char *expr)
{
	struct parse_io io = { .string = expr, .chan = chan };

	ast_yylex_init(&io.scanner);
	ast_yy_scan_string(expr, io.scanner);
	ast_yyparse ((void *) &io);
	ast_yylex_destroy(io.scanner);

	if (!io.val) {
		ast_str_set(str, maxlen, "0");
	} else {
		if (io.val->type == AST_EXPR_number) {
			ast_str_set(str, maxlen, FP___PRINTF, io.val->u.i);
		} else if (io.val->u.s) {
			ast_str_set(str, maxlen, "%s", io.val->u.s);
			free(io.val->u.s);
		}
		free(io.val);
	}
	return ast_str_strlen(*str);
}
#endif


char extra_error_message[4095];
int extra_error_message_supplied = 0;
void  ast_expr_register_extra_error_info(char *message);
void  ast_expr_clear_extra_error_info(void);

void  ast_expr_register_extra_error_info(char *message)
{
       extra_error_message_supplied=1;
       strcpy(extra_error_message, message);
}

void  ast_expr_clear_extra_error_info(void)
{
       extra_error_message_supplied=0;
       extra_error_message[0] = 0;
}

static const char * const expr2_token_equivs1[] = 
{
	"TOKEN",
	"TOK_COND",
	"TOK_COLONCOLON",
	"TOK_OR",
	"TOK_AND",
	"TOK_EQ",
	"TOK_GT",
	"TOK_LT",
	"TOK_GE",
	"TOK_LE",
	"TOK_NE",
	"TOK_PLUS",
	"TOK_MINUS",
	"TOK_MULT",
	"TOK_DIV",
	"TOK_MOD",
	"TOK_COMPL",
	"TOK_COLON",
	"TOK_EQTILDE",
	"TOK_COMMA",
	"TOK_RP",
	"TOK_LP"
};

static const char * const expr2_token_equivs2[] = 
{
	"<token>",
	"?",
	"::",
	"|",
	"&",
	"=",
	">",
	"<",
	">=",
	"<=",
	"!=",
	"+",
	"-",
	"*",
	"/",
	"%",
	"!",
	":",
	"=~",
	",",
	")",
	"("
};


static char *expr2_token_subst(const char *mess)
{
	/* calc a length, malloc, fill, and return; yyerror had better free it! */
	int len=0,i;
	const char *p;
	char *res, *s;
	const char *t;
	int expr2_token_equivs_entries = sizeof(expr2_token_equivs1)/sizeof(char*);

	for (p=mess; *p; p++) {
		for (i=0; i<expr2_token_equivs_entries; i++) {
			if ( strncmp(p,expr2_token_equivs1[i],strlen(expr2_token_equivs1[i])) == 0 )
			{
				len+=strlen(expr2_token_equivs2[i])+2;
				p += strlen(expr2_token_equivs1[i])-1;
				break;
			}
		}
		len++;
	}
	res = (char*)malloc(len+1);
	res[0] = 0;
	s = res;
	for (p=mess; *p;) {
		int found = 0;
		for (i=0; i<expr2_token_equivs_entries; i++) {
			if ( strncmp(p,expr2_token_equivs1[i],strlen(expr2_token_equivs1[i])) == 0 ) {
				*s++ = '\'';
				for (t=expr2_token_equivs2[i]; *t;) {
					*s++ = *t++;
				}
				*s++ = '\'';
				p += strlen(expr2_token_equivs1[i]);
				found = 1;
				break;
			}
		}
		if( !found )
			*s++ = *p++;
	}
	*s++ = 0;
	return res;
}

int ast_yyerror (const char *s,  yyltype *loc, struct parse_io *parseio )
{
	struct yyguts_t * yyg = (struct yyguts_t*)(parseio->scanner);
	char spacebuf[8000]; /* best safe than sorry */
	int i=0;
	char *s2 = expr2_token_subst(s);
	spacebuf[0] = 0;

	for (i = 0; i < (int)(yytext - YY_CURRENT_BUFFER_LVALUE->yy_ch_buf); i++) {
		spacebuf[i] = ' ';
	}
	/* uh... assuming yyg is defined, then I can use the yycolumn macro,
	which is the same thing as... get this:
	yyg->yy_buffer_stack[yyg->yy_buffer_stack_top]->yy_bs_column
	I was tempted to just use yy_buf_pos in the STATE, but..., well:
	a. the yy_buf_pos is the current position in the buffer, which
		may not relate to the entire string/buffer because of the
		buffering.
	b. but, analysis of the situation is that when you use the
		yy_scan_string func, it creates a single buffer the size of
		string, so the two would be the same...
		so, in the end, the yycolumn macro is available, shorter, therefore easier. */

	spacebuf[i++] = '^';
	spacebuf[i] = 0;

#ifdef STANDALONE3
	/* easier to read in the standalone version */
	printf("ast_yyerror(): %s syntax error: %s; Input:\n%s\n%s\n",
			(extra_error_message_supplied ? extra_error_message : ""), s2, parseio->string, spacebuf);
#else
	ast_log(LOG_WARNING,"ast_yyerror(): %s syntax error: %s; Input:\n%s\n%s\n",
			(extra_error_message_supplied ? extra_error_message : ""), s2, parseio->string, spacebuf);
#endif
#ifndef STANDALONE
	ast_log(LOG_WARNING,"If you have questions, please refer to https://wiki.asterisk.org/wiki/display/AST/Channel+Variables\n");
#endif
	free(s2);
	return(0);
}