arch/common/boot/grub2/normal/execute.c

   1 /* execute.c -- Execute a GRUB script.  */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2005,2007  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/mm.h>
  22 #include <grub/normal.h>
  23 #include <grub/arg.h>
  24 #include <grub/env.h>
  25 #include <grub/script.h>
  26
  27 static grub_err_t
  28 grub_script_execute_cmd (struct grub_script_cmd *cmd)
  29 {
  30   if (cmd == 0)
  31     return 0;
  32
  33   return cmd->exec (cmd);
  34 }
  35
  36 /* Parse ARG and return the textual representation.  Add strings are
  37    concatenated and all values of the variables are filled in.  */
  38 static char *
  39 grub_script_execute_argument_to_string (struct grub_script_arg *arg)
  40 {
  41   int size = 0;
  42   char *val;
  43   char *chararg;
  44   struct grub_script_arg *argi;
  45
  46   /* First determine the size of the argument.  */
  47   for (argi = arg; argi; argi = argi->next)
  48     {
  49       if (argi->type == 1)
  50         {
  51           val = grub_env_get (argi->str);
  52           if (val)
  53             size += grub_strlen (val);
  54         }
  55       else
  56         size += grub_strlen (argi->str);
  57     }
  58
  59   /* Create the argument.  */
  60   chararg = grub_malloc (size + 1);
  61   if (! chararg)
  62     return 0;
  63
  64   *chararg = '\0';
  65   /* First determine the size of the argument.  */
  66   for (argi = arg; argi; argi = argi->next)
  67     {
  68       if (argi->type == 1)
  69         {
  70           val = grub_env_get (argi->str);
  71           if (val)
  72             grub_strcat (chararg, val);
  73         }
  74       else
  75         grub_strcat (chararg, argi->str);
  76     }
  77
  78   return chararg;
  79 }
  80
  81 /* Execute a single command line.  */
  82 grub_err_t
  83 grub_script_execute_cmdline (struct grub_script_cmd *cmd)
  84 {
  85   struct grub_script_cmdline *cmdline = (struct grub_script_cmdline *) cmd;
  86   struct grub_script_arglist *arglist;
  87   char **args = 0;
  88   int i = 0;
  89   grub_command_t grubcmd;
  90   struct grub_arg_list *state;
  91   struct grub_arg_option *parser;
  92   int maxargs = 0;
  93   char **parsed_arglist;
  94   int numargs;
  95   grub_err_t ret = 0;
  96   int argcount = 0;
  97   grub_script_function_t func = 0;
  98   char errnobuf[6];
  99
 100   /* Lookup the command.  */
 101   grubcmd = grub_command_find (cmdline->cmdname);
 102   if (! grubcmd)
 103     {
 104       /* Ignore errors.  */
 105       grub_errno = GRUB_ERR_NONE;
 106
 107       /* It's not a GRUB command, try all functions.  */
 108       func = grub_script_function_find (cmdline->cmdname);
 109       if (! func)
 110         {
 111           /* As a last resort, try if it is an assignment.  */
 112           char *assign = grub_strdup (cmdline->cmdname);
 113           char *eq = grub_strchr (assign, '=');
 114
 115           if (eq)
 116             {
 117               /* Create two strings and set the variable.  */
 118               *eq = '\0';
 119               eq++;
 120               grub_env_set (assign, eq);
 121
 122               /* This was set because the command was not found.  */
 123               grub_errno = GRUB_ERR_NONE;
 124             }
 125           grub_free (assign);
 126           return 0;
 127         }
 128     }
 129
 130   if (cmdline->arglist)
 131     {
 132       argcount = cmdline->arglist->argcount;
 133
 134       /* Create argv from the arguments.  */
 135       args = grub_malloc (sizeof (char *) * argcount);
 136       for (arglist = cmdline->arglist; arglist; arglist = arglist->next)
 137         {
 138           char *str;
 139           str = grub_script_execute_argument_to_string (arglist->arg);
 140           args[i++] = str;
 141         }
 142     }
 143
 144   /* Execute the GRUB command or function.  */
 145   if (grubcmd)
 146     {
 147       /* Count the amount of options the command has.  */
 148       parser = (struct grub_arg_option *) grubcmd->options;
 149       while (parser && (parser++)->doc)
 150         maxargs++;
 151
 152       /* Set up the option state.  */
 153       state = grub_malloc (sizeof (struct grub_arg_list) * maxargs);
 154       grub_memset (state, 0, sizeof (struct grub_arg_list) * maxargs);
 155
 156       /* Start the command.  */
 157       if (! (grubcmd->flags & GRUB_COMMAND_FLAG_NO_ARG_PARSE))
 158         {
 159           if (grub_arg_parse (grubcmd, argcount, args, state, &parsed_arglist, &numargs))
 160             ret = (grubcmd->func) (state, numargs, parsed_arglist);
 161         }
 162       else
 163         ret = (grubcmd->func) (state, argcount, args);
 164
 165       grub_free (state);
 166     }
 167   else
 168     ret = grub_script_function_call (func, argcount, args);
 169
 170   /* Free arguments.  */
 171   for (i = 0; i < argcount; i++)
 172     grub_free (args[i]);
 173   grub_free (args);
 174
 175   grub_sprintf (errnobuf, "%d", ret);
 176   grub_env_set ("?", errnobuf);
 177
 178   return ret;
 179 }
 180
 181 /* Execute a block of one or more commands.  */
 182 grub_err_t
 183 grub_script_execute_cmdblock (struct grub_script_cmd *cmd)
 184 {
 185   struct grub_script_cmdblock *cmdblock = (struct grub_script_cmdblock *) cmd;
 186
 187   /* Loop over every command and execute it.  */
 188   for (cmd = cmdblock->cmdlist; cmd; cmd = cmd->next)
 189     grub_script_execute_cmd (cmd);
 190
 191   return 0;
 192 }
 193
 194 /* Execute an if statement.  */
 195 grub_err_t
 196 grub_script_execute_cmdif (struct grub_script_cmd *cmd)
 197 {
 198   struct grub_script_cmdif *cmdif = (struct grub_script_cmdif *) cmd;
 199   char *result;
 200
 201   /* Check if the commands results in a true or a false.  The value is
 202      read from the env variable `?'.  */
 203   grub_script_execute_cmd (cmdif->exec_to_evaluate);
 204   result = grub_env_get ("?");
 205
 206   /* Execute the `if' or the `else' part depending on the value of
 207      `?'.  */
 208   if (result && ! grub_strcmp (result, "0"))
 209     return grub_script_execute_cmd (cmdif->exec_on_true);
 210   else
 211     return grub_script_execute_cmd (cmdif->exec_on_false);
 212 }
 213
 214 /* Execute the menu entry generate statement.  */
 215 grub_err_t
 216 grub_script_execute_menuentry (struct grub_script_cmd *cmd)
 217 {
 218   struct grub_script_cmd_menuentry *cmd_menuentry;
 219   char *title;
 220   struct grub_script *script;
 221
 222   cmd_menuentry = (struct grub_script_cmd_menuentry *) cmd;
 223
 224   /* The title can contain variables, parse them and generate a string
 225      from it.  */
 226   title = grub_script_execute_argument_to_string (cmd_menuentry->title);
 227   if (! title)
 228     return grub_errno;
 229
 230   /* Parse the menu entry *again*.  */
 231   script = grub_script_parse ((char *) cmd_menuentry->sourcecode, 0);
 232
 233   if (! script)
 234     {
 235       grub_free (title);
 236       return grub_errno;
 237     }
 238
 239   /* XXX: When this fails, the memory should be freed?  */
 240   return grub_normal_menu_addentry (title, script,
 241                                     cmd_menuentry->sourcecode);
 242 }
 243
 244 \f
 245
 246 /* Execute any GRUB pre-parsed command or script.  */
 247 grub_err_t
 248 grub_script_execute (struct grub_script *script)
 249 {
 250   if (script == 0)
 251     return 0;
 252
 253   return grub_script_execute_cmd (script->cmd);
 254 }