arch/common/boot/grub2/commands/help.c

   1 /* help.c - command to show a help text.  */
   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/normal.h>
  21 #include <grub/dl.h>
  22 #include <grub/arg.h>
  23 #include <grub/misc.h>
  24 #include <grub/term.h>
  25
  26 static grub_err_t
  27 grub_cmd_help (struct grub_arg_list *state __attribute__ ((unused)), int argc,
  28                char **args)
  29
  30 {
  31   int cnt = 0;
  32   char *currarg;
  33
  34   auto int print_command_info (grub_command_t cmd);
  35   auto int print_command_help (grub_command_t cmd);
  36
  37   int print_command_info (grub_command_t cmd)
  38     {
  39       if (grub_command_find (cmd->name))
  40         {
  41           if (cmd->flags & GRUB_COMMAND_FLAG_CMDLINE)
  42             {
  43               char description[GRUB_TERM_WIDTH / 2];
  44               int desclen = grub_strlen (cmd->summary);
  45
  46               /* Make a string with a length of GRUB_TERM_WIDTH / 2 - 1 filled
  47                  with the description followed by spaces.  */
  48               grub_memset (description, ' ', GRUB_TERM_WIDTH / 2 - 1);
  49               description[GRUB_TERM_WIDTH / 2 - 1] = '\0';
  50               grub_memcpy (description, cmd->summary,
  51                            (desclen < GRUB_TERM_WIDTH / 2 - 1
  52                             ? desclen : GRUB_TERM_WIDTH / 2 - 1));
  53
  54               grub_printf ("%s%s", description, (cnt++) % 2 ? "\n" : " ");
  55             }
  56         }
  57       return 0;
  58     }
  59
  60   int print_command_help (grub_command_t cmd)
  61     {
  62       if (grub_command_find (cmd->name))
  63         {
  64           if (! grub_strncmp (cmd->name, currarg, grub_strlen (currarg)))
  65             {
  66               if (cnt++ > 0)
  67                 grub_printf ("\n\n");
  68
  69               grub_arg_show_help (cmd);
  70             }
  71         }
  72       return 0;
  73     }
  74
  75   if (argc == 0)
  76     grub_iterate_commands (print_command_info);
  77   else
  78     {
  79       int i;
  80
  81       for (i = 0; i < argc; i++)
  82         {
  83           currarg = args[i];
  84           grub_iterate_commands (print_command_help);
  85         }
  86     }
  87
  88   return 0;
  89 }
  90
  91
  92 \f
  93 GRUB_MOD_INIT(help)
  94 {
  95   (void)mod;                    /* To stop warning. */
  96   grub_register_command ("help", grub_cmd_help, GRUB_COMMAND_FLAG_CMDLINE,
  97                          "help [PATTERN ...]", "Show a help message.", 0);
  98 }
  99
 100 GRUB_MOD_FINI(help)
 101 {
 102   grub_unregister_command ("help");
 103 }