kern/rescue.c

   1 /* rescue.c - rescue mode */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2002,2003,2005,2007  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/kernel.h>
  21 #include <grub/rescue.h>
  22 #include <grub/term.h>
  23 #include <grub/misc.h>
  24 #include <grub/disk.h>
  25 #include <grub/file.h>
  26 #include <grub/mm.h>
  27 #include <grub/err.h>
  28 #include <grub/loader.h>
  29 #include <grub/dl.h>
  30 #include <grub/partition.h>
  31 #include <grub/env.h>
  32 #include <grub/parser.h>
  33 #include <grub/list.h>
  34 #include <grub/command.h>
  35
  36 #define GRUB_RESCUE_BUF_SIZE    256
  37 #define GRUB_RESCUE_MAX_ARGS    20
  38
  39 static char linebuf[GRUB_RESCUE_BUF_SIZE];
  40
  41 /* Prompt to input a command and read the line.  */
  42 static void
  43 grub_rescue_get_command_line (const char *prompt)
  44 {
  45   int c;
  46   int pos = 0;
  47
  48   grub_printf (prompt);
  49   grub_memset (linebuf, 0, GRUB_RESCUE_BUF_SIZE);
  50
  51   while ((c = GRUB_TERM_ASCII_CHAR (grub_getkey ())) != '\n' && c != '\r')
  52     {
  53       if (grub_isprint (c))
  54         {
  55           if (pos < GRUB_RESCUE_BUF_SIZE - 1)
  56             {
  57               linebuf[pos++] = c;
  58               grub_putchar (c);
  59             }
  60         }
  61       else if (c == '\b')
  62         {
  63           if (pos > 0)
  64             {
  65               linebuf[--pos] = 0;
  66               grub_putchar (c);
  67               grub_putchar (' ');
  68               grub_putchar (c);
  69             }
  70         }
  71       grub_refresh ();
  72     }
  73
  74   grub_putchar ('\n');
  75   grub_refresh ();
  76 }
  77
  78 static void
  79 attempt_normal_mode (void)
  80 {
  81   grub_command_t cmd;
  82
  83   cmd = grub_command_find ("normal");
  84   if (cmd)
  85     (cmd->func) (cmd, 0, 0);
  86 }
  87
  88 /* Enter the rescue mode.  */
  89 void
  90 grub_enter_rescue_mode (void)
  91 {
  92   auto grub_err_t getline (char **line);
  93
  94   grub_err_t getline (char **line)
  95     {
  96       grub_rescue_get_command_line ("> ");
  97       *line = linebuf;
  98       return 0;
  99     }
 100
 101   grub_register_core_commands ();
 102
 103   /* First of all, attempt to execute the normal mode.  */
 104   attempt_normal_mode ();
 105
 106   grub_printf ("Entering rescue mode...\n");
 107
 108   while (1)
 109     {
 110       char *line = linebuf;
 111       char *name;
 112       int n;
 113       grub_command_t cmd;
 114       char **args;
 115
 116       /* Print an error, if any.  */
 117       grub_print_error ();
 118       grub_errno = GRUB_ERR_NONE;
 119
 120       /* Get a command line.  */
 121       grub_rescue_get_command_line ("grub rescue> ");
 122       if (line[0] == 0)
 123         continue;
 124
 125       if (grub_parser_split_cmdline (line, getline, &n, &args) || n < 0)
 126         continue;
 127
 128       /* In case of an assignment set the environment accordingly
 129          instead of calling a function.  */
 130       if (n == 0 && grub_strchr (line, '='))
 131         {
 132           char *val = grub_strchr (args[0], '=');
 133           val[0] = 0;
 134           grub_env_set (args[0], val + 1);
 135           val[0] = '=';
 136           grub_free (args[0]);
 137           continue;
 138         }
 139
 140       /* Get the command name.  */
 141       name = args[0];
 142
 143       /* If nothing is specified, restart.  */
 144       if (*name == '\0')
 145         {
 146           grub_free (args[0]);
 147           continue;
 148         }
 149
 150       cmd = grub_command_find (name);
 151       if (cmd)
 152         {
 153           (cmd->func) (cmd, n, &args[1]);
 154         }
 155       else
 156         {
 157           grub_printf ("Unknown command `%s'\n", name);
 158           grub_printf ("Try `help' for usage\n");
 159         }
 160
 161       grub_free (args[0]);
 162     }
 163 }