normal/script.c

   1 /* script.c -- Functions to create an in memory description of the script. */
   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 #include <grub/misc.h>
  21 #include <grub/script.h>
  22 #include <grub/parser.h>
  23 #include <grub/mm.h>
  24
  25 /* It is not possible to deallocate the memory when a syntax error was
  26    found.  Because of that it is required to keep track of all memory
  27    allocations.  The memory is freed in case of an error, or
  28    assigned to the parsed script when parsing was successful.  */
  29
  30 /* XXX */
  31
  32 /* In case of the normal malloc, some additional bytes are allocated
  33    for this datastructure.  All reserved memory is stored in a linked
  34    list so it can be easily freed.  The original memory can be found
  35    from &mem.  */
  36 struct grub_script_mem
  37 {
  38   struct grub_script_mem *next;
  39   char mem;
  40 };
  41
  42 /* Return malloc'ed memory and keep track of the allocation.  */
  43 void *
  44 grub_script_malloc (struct grub_parser_param *state, grub_size_t size)
  45 {
  46   struct grub_script_mem *mem;
  47   mem = (struct grub_script_mem *) grub_malloc (size + sizeof (*mem)
  48                                                 - sizeof (char));
  49
  50   grub_dprintf ("scripting", "malloc %p\n", mem);
  51   mem->next = state->memused;
  52   state->memused = mem;
  53   return (void *) &mem->mem;
  54 }
  55
  56 /* Free all memory described by MEM.  */
  57 static void
  58 grub_script_mem_free (struct grub_script_mem *mem)
  59 {
  60   struct grub_script_mem *memfree;
  61
  62   while (mem)
  63     {
  64       memfree = mem->next;
  65       grub_dprintf ("scripting", "free %p\n", mem);
  66       grub_free (mem);
  67       mem = memfree;
  68     }
  69 }
  70
  71 /* Start recording memory usage.  Returns the memory that should be
  72    restored when calling stop.  */
  73 struct grub_script_mem *
  74 grub_script_mem_record (struct grub_parser_param *state)
  75 {
  76   struct grub_script_mem *mem = state->memused;
  77   state->memused = 0;
  78
  79   return mem;
  80 }
  81
  82 /* Stop recording memory usage.  Restore previous recordings using
  83    RESTORE.  Return the recorded memory.  */
  84 struct grub_script_mem *
  85 grub_script_mem_record_stop (struct grub_parser_param *state,
  86                              struct grub_script_mem *restore)
  87 {
  88   struct grub_script_mem *mem = state->memused;
  89   state->memused = restore;
  90   return mem;
  91 }
  92
  93 /* Free the memory reserved for CMD and all of it's children.  */
  94 void
  95 grub_script_free (struct grub_script *script)
  96 {
  97   if (! script)
  98     return;
  99   grub_script_mem_free (script->mem);
 100   grub_free (script);
 101 }
 102
 103 \f
 104
 105 /* Extend the argument arg with a variable or string of text.  If ARG
 106    is zero a new list is created.  */
 107 struct grub_script_arg *
 108 grub_script_arg_add (struct grub_parser_param *state, struct grub_script_arg *arg,
 109                      grub_script_arg_type_t type, char *str)
 110 {
 111   struct grub_script_arg *argpart;
 112   struct grub_script_arg *ll;
 113
 114   argpart = (struct grub_script_arg *) grub_script_malloc (state, sizeof (*arg));
 115   argpart->type = type;
 116   argpart->str = str;
 117   argpart->next = 0;
 118
 119   if (! arg)
 120     return argpart;
 121
 122   for (ll = arg; ll->next; ll = ll->next);
 123   ll->next = argpart;
 124
 125   return arg;
 126 }
 127
 128 /* Add the argument ARG to the end of the argument list LIST.  If LIST
 129    is zero, a new list will be created.  */
 130 struct grub_script_arglist *
 131 grub_script_add_arglist (struct grub_parser_param *state,
 132                          struct grub_script_arglist *list, struct grub_script_arg *arg)
 133 {
 134   struct grub_script_arglist *link;
 135   struct grub_script_arglist *ll;
 136
 137   grub_dprintf ("scripting", "arglist\n");
 138
 139   link = (struct grub_script_arglist *) grub_script_malloc (state, sizeof (*link));
 140   link->next = 0;
 141   link->arg = arg;
 142   link->argcount = 0;
 143
 144   if (! list)
 145     {
 146       link->argcount++;
 147       return link;
 148     }
 149
 150   list->argcount++;
 151
 152   /* Look up the last link in the chain.  */
 153   for (ll = list; ll->next; ll = ll->next);
 154   ll->next = link;
 155
 156   return list;
 157 }
 158
 159 /* Create a command that describes a single command line.  CMDLINE
 160    contains the name of the command that should be executed.  ARGLIST
 161    holds all arguments for this command.  */
 162 struct grub_script_cmd *
 163 grub_script_create_cmdline (struct grub_parser_param *state,
 164                             char *cmdname, struct grub_script_arglist *arglist)
 165 {
 166   struct grub_script_cmdline *cmd;
 167
 168   grub_dprintf ("scripting", "cmdline\n");
 169
 170   cmd = grub_script_malloc (state, sizeof (*cmd));
 171   cmd->cmd.exec = grub_script_execute_cmdline;
 172   cmd->cmd.next = 0;
 173   cmd->arglist = arglist;
 174   cmd->cmdname = cmdname;
 175
 176   return (struct grub_script_cmd *) cmd;
 177 }
 178
 179 /* Create a command that functions as an if statement.  If BOOL is
 180    evaluated to true (the value is returned in envvar '?'), the
 181    interpreter will run the command TRUE, otherwise the interpreter
 182    runs the command FALSE.  */
 183 struct grub_script_cmd *
 184 grub_script_create_cmdif (struct grub_parser_param *state,
 185                           struct grub_script_cmd *exec_to_evaluate,
 186                           struct grub_script_cmd *exec_on_true,
 187                           struct grub_script_cmd *exec_on_false)
 188 {
 189   struct grub_script_cmdif *cmd;
 190
 191   grub_dprintf ("scripting", "cmdif\n");
 192
 193   cmd = grub_script_malloc (state, sizeof (*cmd));
 194   cmd->cmd.exec = grub_script_execute_cmdif;
 195   cmd->cmd.next = 0;
 196   cmd->exec_to_evaluate = exec_to_evaluate;
 197   cmd->exec_on_true = exec_on_true;
 198   cmd->exec_on_false = exec_on_false;
 199
 200   return (struct grub_script_cmd *) cmd;
 201 }
 202
 203 /* Create a command that adds a menu entry to the menu.  Title is an
 204    argument that is parsed to generate a string that can be used as
 205    the title.  The sourcecode for this entry is passed in SOURCECODE.
 206    The options for this entry are passed in OPTIONS.  */
 207 struct grub_script_cmd *
 208 grub_script_create_cmdmenu (struct grub_parser_param *state,
 209                             struct grub_script_arg *title,
 210                             char *sourcecode,
 211                             int options)
 212 {
 213   struct grub_script_cmd_menuentry *cmd;
 214   int i;
 215
 216   /* Skip leading newlines to make the sourcecode better readable when
 217      using the editor.  */
 218   while (*sourcecode == '\n')
 219     sourcecode++;
 220
 221   /* Having trailing returns can some some annoying conflicts, remove
 222      them.  XXX: Can the parser be improved to handle this?  */
 223   for (i = grub_strlen (sourcecode) - 1; i > 0; i--)
 224     {
 225       if (sourcecode[i] != '\n')
 226         break;
 227       sourcecode[i] = '\0';
 228     }
 229
 230   cmd = grub_script_malloc (state, sizeof (*cmd));
 231   cmd->cmd.exec = grub_script_execute_menuentry;
 232   cmd->cmd.next = 0;
 233   /* XXX: Check if this memory is properly freed.  */
 234   cmd->sourcecode = sourcecode;
 235   cmd->title = title;
 236   cmd->options = options;
 237
 238   return (struct grub_script_cmd *) cmd;
 239 }
 240
 241 /* Create a block of commands.  CMD contains the command that should
 242    be added at the end of CMDBLOCK's list.  If CMDBLOCK is zero, a new
 243    cmdblock will be created.  */
 244 struct grub_script_cmd *
 245 grub_script_add_cmd (struct grub_parser_param *state,
 246                      struct grub_script_cmdblock *cmdblock,
 247                      struct grub_script_cmd *cmd)
 248 {
 249   grub_dprintf ("scripting", "cmdblock\n");
 250
 251   if (! cmd)
 252     return (struct grub_script_cmd *) cmdblock;
 253
 254   if (! cmdblock)
 255     {
 256       cmdblock = (struct grub_script_cmdblock *) grub_script_malloc (state,
 257                                                                      sizeof (*cmdblock));
 258       cmdblock->cmd.exec = grub_script_execute_cmdblock;
 259       cmdblock->cmd.next = 0;
 260       cmdblock->cmdlist = cmd;
 261       cmd->next = 0;
 262     }
 263   else
 264     {
 265       cmd->next = cmdblock->cmdlist;
 266       cmdblock->cmdlist = cmd;
 267     }
 268
 269   return (struct grub_script_cmd *) cmdblock;
 270 }
 271
 272 \f
 273
 274 struct grub_script *
 275 grub_script_create (struct grub_script_cmd *cmd, struct grub_script_mem *mem)
 276 {
 277   struct grub_script *parsed;
 278
 279   parsed = grub_malloc (sizeof (*parsed));
 280   if (! parsed)
 281     {
 282       grub_script_mem_free (mem);
 283       grub_free (cmd);
 284
 285       return 0;
 286     }
 287
 288   parsed->mem = mem;
 289   parsed->cmd = cmd;
 290
 291   return parsed;
 292 }
 293
 294 /* Parse the script passed in SCRIPT and return the parsed
 295    datastructure that is ready to be interpreted.  */
 296 struct grub_script *
 297 grub_script_parse (char *script, grub_err_t (*getline) (char **))
 298 {
 299   struct grub_script *parsed;
 300   struct grub_script_mem *membackup;
 301   struct grub_lexer_param *lexstate;
 302   struct grub_parser_param *parsestate;
 303
 304   parsed = grub_malloc (sizeof (*parsed));
 305   if (! parsed)
 306     return 0;
 307
 308   parsestate = grub_malloc (sizeof (*parsestate));
 309   if (! parsestate)
 310     return 0;
 311
 312   parsestate->err = 0;
 313   parsestate->func_mem = 0;
 314   parsestate->memused = 0;
 315   parsestate->parsed = 0;
 316
 317   /* Initialize the lexer.  */
 318   lexstate = grub_script_lexer_init (script, getline);
 319   if (! lexstate)
 320     {
 321       grub_free (parsed);
 322       grub_free (parsestate);
 323       return 0;
 324     }
 325
 326   parsestate->lexerstate = lexstate;
 327
 328   membackup = grub_script_mem_record (parsestate);
 329
 330   /* Parse the script.  */
 331   if (grub_script_yyparse (parsestate) || parsestate->err)
 332     {
 333       struct grub_script_mem *memfree;
 334       memfree = grub_script_mem_record_stop (parsestate, membackup);
 335       grub_script_mem_free (memfree);
 336       grub_free (lexstate);
 337       grub_free (parsestate);
 338       return 0;
 339     }
 340
 341   parsed->mem = grub_script_mem_record_stop (parsestate, membackup);
 342   parsed->cmd = parsestate->parsed;
 343
 344   grub_free (lexstate);
 345   grub_free (parsestate);
 346
 347   return parsed;
 348 }