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/*
* (C) 2006, 2007 Andreas Gruenbacher <agruen@suse.de>
* Copyright (c) 2003-2008 Novell, Inc. (All rights reserved)
* Copyright 2009-2010 Canonical Ltd.
*
* The libapparmor library is licensed under the terms of the GNU
* Lesser General Public License, version 2.1. Please see the file
* COPYING.LGPL.
*
* This library 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*
* Parsing of regular expression into expression trees as implemented in
* expr-tree
*/
%{
/* #define DEBUG_TREE */
#include "expr-tree.h"
%}
%union {
char c;
Node *node;
Chars *cset;
}
%{
void regex_error(Node **, const char *, const char *);
#define YYLEX_PARAM &text
int regex_lex(YYSTYPE *, const char **);
static inline Chars *insert_char(Chars* cset, transchar a)
{
cset->insert(a);
return cset;
}
static inline Chars* insert_char_range(Chars* cset, transchar a, transchar b)
{
if (a > b)
swap(a, b);
for (transchar i = a; i <= b; i++)
cset->insert(i);
return cset;
}
%}
%define api.pure
/* %error-verbose */
%lex-param {YYLEX_PARAM}
%parse-param {Node **root}
%parse-param {const char *text}
%name-prefix "regex_"
%token <c> CHAR
%type <c> regex_char cset_char1 cset_char cset_charN
%type <cset> charset cset_chars
%type <node> regex expr terms0 terms qterm term
/**
* Note: destroy all nodes upon failure, but *not* the start symbol once
* parsing succeeds!
*/
%destructor { $$->release(); } expr terms0 terms qterm term
%destructor { delete $$; } charset cset_chars
%%
/* FIXME: Does not parse "[--]", "[---]", "[^^-x]". I don't actually know
which precise grammar Perl regexs use, and rediscovering that
is proving to be painful. */
regex : /* empty */ { *root = $$ = &epsnode; }
| expr { *root = $$ = $1; }
;
expr : terms
| expr '|' terms0 { $$ = new AltNode($1, $3); }
| '|' terms0 { $$ = new AltNode(&epsnode, $2); }
;
terms0 : /* empty */ { $$ = &epsnode; }
| terms
;
terms : qterm
| terms qterm { $$ = new CatNode($1, $2); }
;
qterm : term
| term '*' { $$ = new StarNode($1); }
| term '+' { $$ = new PlusNode($1); }
;
term : '.' { $$ = new AnyCharNode; }
| regex_char { $$ = new CharNode($1); }
| '[' charset ']' { $$ = new CharSetNode(*$2);
delete $2; }
| '[' '^' charset ']'
{ $$ = new NotCharSetNode(*$3);
delete $3; }
| '[' '^' '^' cset_chars ']'
{ $4->insert('^');
$$ = new NotCharSetNode(*$4);
delete $4; }
| '(' regex ')' { $$ = $2; }
;
regex_char : CHAR
| '^' { $$ = '^'; }
| '-' { $$ = '-'; }
| ']' { $$ = ']'; }
;
charset : cset_char1 cset_chars
{ $$ = insert_char($2, $1); }
| cset_char1 '-' cset_charN cset_chars
{ $$ = insert_char_range($4, $1, $3); }
;
cset_chars : /* nothing */ { $$ = new Chars; }
| cset_chars cset_charN
{ $$ = insert_char($1, $2); }
| cset_chars cset_charN '-' cset_charN
{ $$ = insert_char_range($1, $2, $4); }
;
cset_char1 : cset_char
| ']' { $$ = ']'; }
| '-' { $$ = '-'; }
;
cset_charN : cset_char
| '^' { $$ = '^'; }
;
cset_char : CHAR
| '[' { $$ = '['; }
| '*' { $$ = '*'; }
| '+' { $$ = '+'; }
| '.' { $$ = '.'; }
| '|' { $$ = '|'; }
| '(' { $$ = '('; }
| ')' { $$ = ')'; }
;
%%
#include "../lib.h"
int regex_lex(YYSTYPE *val, const char **pos)
{
int tmp;
val->c = **pos;
switch(*(*pos)++) {
case '\0':
(*pos)--;
return 0;
case '*': case '+': case '.': case '|': case '^': case '-':
case '[': case ']': case '(' : case ')':
return *(*pos - 1);
case '\\':
tmp = str_escseq(pos, "*+.|^$-[](){}");
if (tmp == -1) {
/* bad escape sequence, just skip it for now, that
* is output \\ followed by the invalid esc seq
* TODO: output error message
*/
val->c = '\\';
(*pos)--;
} else
val->c = tmp;
break;
}
return CHAR;
}
void regex_error(Node ** __attribute__((unused)),
const char *text __attribute__((unused)),
const char *error __attribute__((unused)))
{
/* We don't want the library to print error messages. */
}
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