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