arch/common/boot/grub2/normal/parser.y

   1 /* parser.y - The scripting parser.  */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2005,2006,2007  Free Software Foundation, Inc.
   5  *
   6  *  GRUB is free software: you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation, either version 3 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  GRUB is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 %{
  21 #include <grub/script.h>
  22 #include <grub/mm.h>
  23
  24 #define YYFREE          grub_free
  25 #define YYMALLOC        grub_malloc
  26 #define YYLTYPE_IS_TRIVIAL      0
  27 #define YYENABLE_NLS    0
  28
  29 %}
  30
  31 %union {
  32   struct grub_script_cmd *cmd;
  33   struct grub_script_arglist *arglist;
  34   struct grub_script_arg *arg;
  35   char *string;
  36 }
  37
  38 %token GRUB_PARSER_TOKEN_IF             "if"
  39 %token GRUB_PARSER_TOKEN_WHILE          "while"
  40 %token GRUB_PARSER_TOKEN_FUNCTION       "function"
  41 %token GRUB_PARSER_TOKEN_MENUENTRY      "menuentry"
  42 %token GRUB_PARSER_TOKEN_ELSE           "else"
  43 %token GRUB_PARSER_TOKEN_THEN           "then"
  44 %token GRUB_PARSER_TOKEN_FI             "fi"
  45 %token GRUB_PARSER_TOKEN_NAME
  46 %token GRUB_PARSER_TOKEN_VAR
  47 %type <cmd> script_init script grubcmd command commands commandblock menuentry if
  48 %type <arglist> arguments;
  49 %type <arg> argument;
  50 %type <string> "if" "while" "function" "else" "then" "fi"
  51 %type <string> text GRUB_PARSER_TOKEN_NAME GRUB_PARSER_TOKEN_VAR
  52
  53 %pure-parser
  54 %lex-param { struct grub_parser_param *state };
  55 %parse-param { struct grub_parser_param *state };
  56
  57 %%
  58 /* It should be possible to do this in a clean way...  */
  59 script_init:    { state->err = 0} script
  60                   {
  61                     state->parsed = $2;
  62                   }
  63 ;
  64
  65 script:         commands { $$ = $1; }
  66                 | function '\n' { $$ = 0; }
  67                 | menuentry '\n' { $$ = $1; }
  68 ;
  69
  70 delimiter:      '\n'
  71                 | ';'
  72                 | delimiter '\n'
  73 ;
  74
  75 newlines:       /* Empty */
  76                 | newlines '\n'
  77 ;
  78
  79 /* Some tokens are both used as token or as plain text.  XXX: Add all
  80    tokens without causing conflicts.  */
  81 text:           GRUB_PARSER_TOKEN_NAME
  82                   {
  83                     $$ = $1;
  84                   }
  85                 | "if"
  86                   {
  87                     $$ = $1;
  88                   }
  89                 | "while"
  90                   {
  91                     $$ = $1;
  92                   }
  93 ;
  94
  95 /* An argument can consist of some static text mixed with variables,
  96    for example: `foo${bar}baz'.  */
  97 argument:       GRUB_PARSER_TOKEN_VAR
  98                   {
  99                     $$ = grub_script_arg_add (state, 0, GRUB_SCRIPT_ARG_TYPE_VAR, $1);
 100                   }
 101                 | text
 102                   {
 103                     $$ = grub_script_arg_add (state, 0, GRUB_SCRIPT_ARG_TYPE_STR, $1);
 104                   }
 105 /* XXX: Currently disabled to simplify the parser.  This should be
 106    parsed by yet another parser for readability.  */
 107 /*              | argument GRUB_PARSER_TOKEN_VAR */
 108 /*                { */
 109 /*                  $$ = grub_script_arg_add ($1, GRUB_SCRIPT_ARG_TYPE_VAR, $2); */
 110 /*                } */
 111 /*              | argument text */
 112 /*                { */
 113 /*                  $$ = grub_script_arg_add ($1, GRUB_SCRIPT_ARG_TYPE_STR, $2); */
 114 /*                } */
 115 ;
 116
 117 arguments:      argument
 118                   {
 119                     $$ = grub_script_add_arglist (state, 0, $1);
 120                   }
 121                 | arguments argument
 122                   {
 123                     $$ = grub_script_add_arglist (state, $1, $2);
 124                   }
 125 ;
 126
 127 grubcmd:        GRUB_PARSER_TOKEN_NAME arguments
 128                   {
 129                     $$ = grub_script_create_cmdline (state, $1, $2);
 130                   }
 131                 | GRUB_PARSER_TOKEN_NAME
 132                   {
 133                     $$ = grub_script_create_cmdline (state, $1, 0);
 134                   }
 135 ;
 136
 137 /* A single command.  */
 138 command:        grubcmd delimiter { $$ = $1; }
 139                 | if delimiter  { $$ = $1; }
 140                 | commandblock delimiter { $$ = $1; }
 141                 | error delimiter
 142                   {
 143                     $$ = 0;
 144                     yyerror (state, "Incorrect command");
 145                     state->err = 1;
 146                     yyerrok;
 147                   }
 148 ;
 149
 150 /* A block of commands.  */
 151 commands:       command
 152                   {
 153                     $$ = grub_script_add_cmd (state, 0, $1);
 154                   }
 155                 | command commands
 156                   {
 157                     struct grub_script_cmdblock *cmd;
 158                     cmd = (struct grub_script_cmdblock *) $2;
 159                     $$ = grub_script_add_cmd (state, cmd, $1);
 160                   }
 161 ;
 162
 163 /* A function.  Carefully save the memory that is allocated.  Don't
 164    change any stuff because it might seem like a fun thing to do!
 165    Special care was take to make sure the mid-rule actions are
 166    executed on the right moment.  So the `commands' rule should be
 167    recognized after executing the `grub_script_mem_record; and before
 168    `grub_script_mem_record_stop'.  */
 169 function:       "function" GRUB_PARSER_TOKEN_NAME
 170                   {
 171                     grub_script_lexer_ref (state->lexerstate);
 172                   } newlines '{'
 173                   {
 174                     /* The first part of the function was recognized.
 175                        Now start recording the memory usage to store
 176                        this function.  */
 177                     state->func_mem = grub_script_mem_record (state);
 178                   } newlines commands '}'
 179                   {
 180                     struct grub_script *script;
 181
 182                     /* All the memory usage for parsing this function
 183                        was recorded.  */
 184                     state->func_mem = grub_script_mem_record_stop (state,
 185                                                                    state->func_mem);
 186                     script = grub_script_create ($8, state->func_mem);
 187                     if (script)
 188                       grub_script_function_create ($2, script);
 189                     grub_script_lexer_deref (state->lexerstate);
 190                   }
 191 ;
 192
 193 /* Carefully designed, together with `menuentry' so everything happens
 194    just in the expected order.  */
 195 commandblock:   '{'
 196                   {
 197                     grub_script_lexer_ref (state->lexerstate);
 198                   }
 199                 newlines commands '}'
 200                   {
 201                     grub_script_lexer_deref (state->lexerstate);
 202                     $$ = $4;
 203                   }
 204 ;
 205
 206 /* A menu entry.  Carefully save the memory that is allocated.  */
 207 menuentry:      "menuentry" argument
 208                   {
 209                     grub_script_lexer_ref (state->lexerstate);
 210                   } newlines '{'
 211                   {
 212                     grub_script_lexer_record_start (state->lexerstate);
 213                   } newlines commands '}'
 214                   {
 215                     char *menu_entry;
 216                     menu_entry = grub_script_lexer_record_stop (state->lexerstate);
 217                     grub_script_lexer_deref (state->lexerstate);
 218                     $$ = grub_script_create_cmdmenu (state, $2, menu_entry, 0);
 219                   }
 220 ;
 221
 222 /* The first part of the if statement.  It's used to switch the lexer
 223    to a state in which it demands more tokens.  */
 224 if_statement:   "if" { grub_script_lexer_ref (state->lexerstate); }
 225 ;
 226
 227 /* The if statement.  */
 228 if:              if_statement commands "then" newlines commands "fi"
 229                   {
 230                     $$ = grub_script_create_cmdif (state, $2, $5, 0);
 231                     grub_script_lexer_deref (state->lexerstate);
 232                   }
 233                  | if_statement commands "then" newlines commands "else" newlines commands  "fi"
 234                   {
 235                     $$ = grub_script_create_cmdif (state, $2, $5, $8);
 236                     grub_script_lexer_deref (state->lexerstate);
 237                   }
 238 ;