GRUB2/MOD_SRC/grub-2.04/grub-core/normal/context.c

   1 /* env.c - Environment variables */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2003,2005,2006,2007,2008,2009  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/env.h>
  21 #include <grub/env_private.h>
  22 #include <grub/misc.h>
  23 #include <grub/mm.h>
  24 #include <grub/command.h>
  25 #include <grub/normal.h>
  26 #include <grub/i18n.h>
  27
  28 struct menu_pointer
  29 {
  30   grub_menu_t menu;
  31   struct menu_pointer *prev;
  32 };
  33
  34 static struct menu_pointer initial_menu;
  35 static struct menu_pointer *current_menu = &initial_menu;
  36
  37 void
  38 grub_env_unset_menu (void)
  39 {
  40   current_menu->menu = NULL;
  41 }
  42
  43 grub_menu_t
  44 grub_env_get_menu (void)
  45 {
  46   return current_menu->menu;
  47 }
  48
  49 void
  50 grub_env_set_menu (grub_menu_t nmenu)
  51 {
  52   current_menu->menu = nmenu;
  53 }
  54
  55 static grub_err_t
  56 grub_env_new_context (int export_all)
  57 {
  58   struct grub_env_context *context;
  59   int i;
  60   struct menu_pointer *menu;
  61
  62   context = grub_zalloc (sizeof (*context));
  63   if (! context)
  64     return grub_errno;
  65   menu = grub_zalloc (sizeof (*menu));
  66   if (! menu)
  67     {
  68       grub_free (context);
  69       return grub_errno;
  70     }
  71
  72   context->prev = grub_current_context;
  73   grub_current_context = context;
  74
  75   menu->prev = current_menu;
  76   current_menu = menu;
  77
  78   /* Copy exported variables.  */
  79   for (i = 0; i < HASHSZ; i++)
  80     {
  81       struct grub_env_var *var;
  82
  83       for (var = context->prev->vars[i]; var; var = var->next)
  84         if (var->global || export_all)
  85           {
  86             if (grub_env_set (var->name, var->value) != GRUB_ERR_NONE)
  87               {
  88                 grub_env_context_close ();
  89                 return grub_errno;
  90               }
  91             grub_env_export (var->name);
  92             grub_register_variable_hook (var->name, var->read_hook, var->write_hook);
  93           }
  94     }
  95
  96   return GRUB_ERR_NONE;
  97 }
  98
  99 grub_err_t
 100 grub_env_context_open (void)
 101 {
 102   return grub_env_new_context (1);
 103 }
 104
 105 int grub_extractor_level = 0;
 106
 107 grub_err_t
 108 grub_env_extractor_open (int source)
 109 {
 110   grub_extractor_level++;
 111   return grub_env_new_context (source);
 112 }
 113
 114 grub_err_t
 115 grub_env_context_close (void)
 116 {
 117   struct grub_env_context *context;
 118   int i;
 119   struct menu_pointer *menu;
 120
 121   if (! grub_current_context->prev)
 122     return grub_error (GRUB_ERR_BAD_ARGUMENT,
 123                        "cannot close the initial context");
 124
 125   /* Free the variables associated with this context.  */
 126   for (i = 0; i < HASHSZ; i++)
 127     {
 128       struct grub_env_var *p, *q;
 129
 130       for (p = grub_current_context->vars[i]; p; p = q)
 131         {
 132           q = p->next;
 133           grub_free (p->name);
 134           grub_free (p->value);
 135           grub_free (p);
 136         }
 137     }
 138
 139   /* Restore the previous context.  */
 140   context = grub_current_context->prev;
 141   grub_free (grub_current_context);
 142   grub_current_context = context;
 143
 144   menu = current_menu->prev;
 145   if (current_menu->menu)
 146     grub_normal_free_menu (current_menu->menu);
 147   grub_free (current_menu);
 148   current_menu = menu;
 149
 150   return GRUB_ERR_NONE;
 151 }
 152
 153 grub_err_t
 154 grub_env_extractor_close (int source)
 155 {
 156   grub_menu_t menu = NULL;
 157   grub_menu_entry_t *last;
 158   grub_err_t err;
 159
 160   if (source)
 161     {
 162       menu = grub_env_get_menu ();
 163       grub_env_unset_menu ();
 164     }
 165   err = grub_env_context_close ();
 166
 167   if (source && menu)
 168     {
 169       grub_menu_t menu2;
 170       menu2 = grub_env_get_menu ();
 171
 172       last = &menu2->entry_list;
 173       while (*last)
 174         last = &(*last)->next;
 175
 176       *last = menu->entry_list;
 177       menu2->size += menu->size;
 178     }
 179
 180   grub_extractor_level--;
 181   return err;
 182 }
 183
 184 static grub_command_t export_cmd;
 185
 186 static grub_err_t
 187 grub_cmd_export (struct grub_command *cmd __attribute__ ((unused)),
 188                  int argc, char **args)
 189 {
 190   int i;
 191
 192   if (argc < 1)
 193     return grub_error (GRUB_ERR_BAD_ARGUMENT,
 194                        N_("one argument expected"));
 195
 196   for (i = 0; i < argc; i++)
 197     grub_env_export (args[i]);
 198
 199   return 0;
 200 }
 201
 202 void
 203 grub_context_init (void)
 204 {
 205   export_cmd = grub_register_command ("export", grub_cmd_export,
 206                                       N_("ENVVAR [ENVVAR] ..."),
 207                                       N_("Export variables."));
 208 }
 209
 210 void
 211 grub_context_fini (void)
 212 {
 213   grub_unregister_command (export_cmd);
 214 }