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grub/grub-core/script/parser.y

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/* parser.y - The scripting parser. */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2005,2006,2007,2008,2009,2010 Free Software Foundation, Inc.
*
* GRUB 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 3 of the License, or
* (at your option) any later version.
*
* GRUB 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 GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
%{
#include <grub/script_sh.h>
#include <grub/mm.h>
#include <grub/misc.h>
#include <grub/i18n.h>
#define YYFREE grub_free
#define YYMALLOC grub_malloc
#define YYLTYPE_IS_TRIVIAL 0
#define YYENABLE_NLS 0
#include "grub_script.tab.h"
#pragma GCC diagnostic ignored "-Wmissing-declarations"
%}
%union {
struct grub_script_cmd *cmd;
struct grub_script_arglist *arglist;
struct grub_script_arg *arg;
char *string;
struct {
unsigned offset;
struct grub_script_mem *memory;
struct grub_script *scripts;
};
}
%token GRUB_PARSER_TOKEN_BAD
%token GRUB_PARSER_TOKEN_EOF 0 "end-of-input"
%token GRUB_PARSER_TOKEN_NEWLINE "\n"
%token GRUB_PARSER_TOKEN_AND "&&"
%token GRUB_PARSER_TOKEN_OR "||"
%token GRUB_PARSER_TOKEN_SEMI2 ";;"
%token GRUB_PARSER_TOKEN_PIPE "|"
%token GRUB_PARSER_TOKEN_AMP "&"
%token GRUB_PARSER_TOKEN_SEMI ";"
%token GRUB_PARSER_TOKEN_LBR "{"
%token GRUB_PARSER_TOKEN_RBR "}"
%token GRUB_PARSER_TOKEN_NOT "!"
%token GRUB_PARSER_TOKEN_LSQBR2 "["
%token GRUB_PARSER_TOKEN_RSQBR2 "]"
%token GRUB_PARSER_TOKEN_LT "<"
%token GRUB_PARSER_TOKEN_GT ">"
%token <arg> GRUB_PARSER_TOKEN_CASE "case"
%token <arg> GRUB_PARSER_TOKEN_DO "do"
%token <arg> GRUB_PARSER_TOKEN_DONE "done"
%token <arg> GRUB_PARSER_TOKEN_ELIF "elif"
%token <arg> GRUB_PARSER_TOKEN_ELSE "else"
%token <arg> GRUB_PARSER_TOKEN_ESAC "esac"
%token <arg> GRUB_PARSER_TOKEN_FI "fi"
%token <arg> GRUB_PARSER_TOKEN_FOR "for"
%token <arg> GRUB_PARSER_TOKEN_IF "if"
%token <arg> GRUB_PARSER_TOKEN_IN "in"
%token <arg> GRUB_PARSER_TOKEN_SELECT "select"
%token <arg> GRUB_PARSER_TOKEN_THEN "then"
%token <arg> GRUB_PARSER_TOKEN_UNTIL "until"
%token <arg> GRUB_PARSER_TOKEN_WHILE "while"
%token <arg> GRUB_PARSER_TOKEN_FUNCTION "function"
%token <arg> GRUB_PARSER_TOKEN_NAME "name"
%token <arg> GRUB_PARSER_TOKEN_WORD "word"
%type <arg> block block0
%type <arglist> word argument arguments0 arguments1
%type <cmd> script_init script
%type <cmd> grubcmd ifclause ifcmd forcmd whilecmd untilcmd
%type <cmd> command commands1 statement
%pure-parser
%lex-param { struct grub_parser_param *state };
%parse-param { struct grub_parser_param *state };
%start script_init
%%
/* It should be possible to do this in a clean way... */
script_init: { state->err = 0; } script { state->parsed = $2; state->err = 0; }
;
script: newlines0
{
$$ = 0;
}
| script statement delimiter newlines0
{
$$ = grub_script_append_cmd (state, $1, $2);
}
| error
{
$$ = 0;
yyerror (state, N_("Incorrect command"));
yyerrok;
}
;
newlines0: /* Empty */ | newlines1 ;
newlines1: newlines0 "\n" ;
delimiter: ";"
| "\n"
;
delimiters0: /* Empty */ | delimiters1 ;
delimiters1: delimiter
| delimiters1 "\n"
;
word: GRUB_PARSER_TOKEN_NAME { $$ = grub_script_add_arglist (state, 0, $1); }
| GRUB_PARSER_TOKEN_WORD { $$ = grub_script_add_arglist (state, 0, $1); }
;
statement: command { $$ = $1; }
| function { $$ = 0; }
;
argument : "case" { $$ = grub_script_add_arglist (state, 0, $1); }
| "do" { $$ = grub_script_add_arglist (state, 0, $1); }
| "done" { $$ = grub_script_add_arglist (state, 0, $1); }
| "elif" { $$ = grub_script_add_arglist (state, 0, $1); }
| "else" { $$ = grub_script_add_arglist (state, 0, $1); }
| "esac" { $$ = grub_script_add_arglist (state, 0, $1); }
| "fi" { $$ = grub_script_add_arglist (state, 0, $1); }
| "for" { $$ = grub_script_add_arglist (state, 0, $1); }
| "if" { $$ = grub_script_add_arglist (state, 0, $1); }
| "in" { $$ = grub_script_add_arglist (state, 0, $1); }
| "select" { $$ = grub_script_add_arglist (state, 0, $1); }
| "then" { $$ = grub_script_add_arglist (state, 0, $1); }
| "until" { $$ = grub_script_add_arglist (state, 0, $1); }
| "while" { $$ = grub_script_add_arglist (state, 0, $1); }
| "function" { $$ = grub_script_add_arglist (state, 0, $1); }
| word { $$ = $1; }
;
/*
Block parameter is passed to commands in two forms: as unparsed
string and as pre-parsed grub_script object. Passing as grub_script
object makes memory management difficult, because:
(1) Command may want to keep a reference to grub_script objects for
later use, so script framework may not free the grub_script
object after command completes.
(2) Command may get called multiple times with same grub_script
object under loops, so we should not let command implementation
to free the grub_script object.
To solve above problems, we rely on reference counting for
grub_script objects. Commands that want to keep the grub_script
object must take a reference to it.
Other complexity comes with arbitrary nesting of grub_script
objects: a grub_script object may have commands with several block
parameters, and each block parameter may further contain multiple
block parameters nested. We use temporary variable, state->scripts
to collect nested child scripts (that are linked by siblings and
children members), and will build grub_scripts tree from bottom.
*/
block: "{"
{
grub_script_lexer_ref (state->lexerstate);
$<offset>$ = grub_script_lexer_record_start (state);
$<memory>$ = grub_script_mem_record (state);
/* save currently known scripts. */
$<scripts>$ = state->scripts;
state->scripts = 0;
}
commands1 delimiters0 "}"
{
char *p;
struct grub_script_mem *memory;
struct grub_script *s = $<scripts>2;
memory = grub_script_mem_record_stop (state, $<memory>2);
if ((p = grub_script_lexer_record_stop (state, $<offset>2)))
*grub_strrchr (p, '}') = '\0';
$$ = grub_script_arg_add (state, 0, GRUB_SCRIPT_ARG_TYPE_BLOCK, p);
if (! $$ || ! ($$->script = grub_script_create ($3, memory)))
grub_script_mem_free (memory);
else {
/* attach nested scripts to $$->script as children */
$$->script->children = state->scripts;
/* restore old scripts; append $$->script to siblings. */
state->scripts = $<scripts>2 ?: $$->script;
if (s) {
while (s->next_siblings)
s = s->next_siblings;
s->next_siblings = $$->script;
}
}
grub_script_lexer_deref (state->lexerstate);
}
;
block0: /* Empty */ { $$ = 0; }
| block { $$ = $1; }
;
arguments0: /* Empty */ { $$ = 0; }
| arguments1 { $$ = $1; }
;
arguments1: argument arguments0
{
if ($1 && $2)
{
$1->next = $2;
$1->argcount += $2->argcount;
$2->argcount = 0;
}
$$ = $1;
}
;
grubcmd: word arguments0 block0
{
struct grub_script_arglist *x = $2;
if ($3)
x = grub_script_add_arglist (state, $2, $3);
if ($1 && x) {
$1->next = x;
$1->argcount += x->argcount;
x->argcount = 0;
}
$$ = grub_script_create_cmdline (state, $1);
}
;
/* A single command. */
command: grubcmd { $$ = $1; }
| ifcmd { $$ = $1; }
| forcmd { $$ = $1; }
| whilecmd { $$ = $1; }
| untilcmd { $$ = $1; }
;
/* A list of commands. */
commands1: newlines0 command
{
$$ = grub_script_append_cmd (state, 0, $2);
}
| commands1 delimiters1 command
{
$$ = grub_script_append_cmd (state, $1, $3);
}
;
function: "function" "name"
{
grub_script_lexer_ref (state->lexerstate);
state->func_mem = grub_script_mem_record (state);
$<scripts>$ = state->scripts;
state->scripts = 0;
}
newlines0 "{" commands1 delimiters1 "}"
{
struct grub_script *script;
state->func_mem = grub_script_mem_record_stop (state,
state->func_mem);
script = grub_script_create ($6, state->func_mem);
if (! script)
grub_script_mem_free (state->func_mem);
else {
script->children = state->scripts;
if (!grub_script_function_create ($2, script))
grub_script_free (script);
}
state->scripts = $<scripts>3;
grub_script_lexer_deref (state->lexerstate);
}
;
ifcmd: "if"
{
grub_script_lexer_ref (state->lexerstate);
}
ifclause "fi"
{
$$ = $3;
grub_script_lexer_deref (state->lexerstate);
}
;
ifclause: commands1 delimiters1 "then" commands1 delimiters1
{
$$ = grub_script_create_cmdif (state, $1, $4, 0);
}
| commands1 delimiters1 "then" commands1 delimiters1 "else" commands1 delimiters1
{
$$ = grub_script_create_cmdif (state, $1, $4, $7);
}
| commands1 delimiters1 "then" commands1 delimiters1 "elif" ifclause
{
$$ = grub_script_create_cmdif (state, $1, $4, $7);
}
;
forcmd: "for" "name"
{
grub_script_lexer_ref (state->lexerstate);
}
"in" arguments0 delimiters1 "do" commands1 delimiters1 "done"
{
$$ = grub_script_create_cmdfor (state, $2, $5, $8);
grub_script_lexer_deref (state->lexerstate);
}
;
whilecmd: "while"
{
grub_script_lexer_ref (state->lexerstate);
}
commands1 delimiters1 "do" commands1 delimiters1 "done"
{
$$ = grub_script_create_cmdwhile (state, $3, $6, 0);
grub_script_lexer_deref (state->lexerstate);
}
;
untilcmd: "until"
{
grub_script_lexer_ref (state->lexerstate);
}
commands1 delimiters1 "do" commands1 delimiters1 "done"
{
$$ = grub_script_create_cmdwhile (state, $3, $6, 1);
grub_script_lexer_deref (state->lexerstate);
}
;
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