grub-core/commands/help.c

   1 /* help.c - command to show a help text.  */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2005,2007,2008,2009  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/dl.h>
  21 #include <grub/misc.h>
  22 #include <grub/term.h>
  23 #include <grub/extcmd.h>
  24 #include <grub/i18n.h>
  25 #include <grub/mm.h>
  26 #include <grub/normal.h>
  27 #include <grub/charset.h>
  28
  29 GRUB_MOD_LICENSE ("GPLv3+");
  30
  31 static grub_err_t
  32 grub_cmd_help (grub_extcmd_context_t ctxt __attribute__ ((unused)), int argc,
  33                char **args)
  34 {
  35   int cnt = 0;
  36   char *currarg;
  37
  38   if (argc == 0)
  39     {
  40       grub_command_t cmd;
  41       FOR_COMMANDS(cmd)
  42       {
  43         if ((cmd->prio & GRUB_PRIO_LIST_FLAG_ACTIVE))
  44           {
  45             struct grub_term_output *term;
  46             const char *summary_translated = _(cmd->summary);
  47             char *command_help;
  48             grub_uint32_t *unicode_command_help;
  49             grub_uint32_t *unicode_last_position;
  50
  51             command_help = grub_xasprintf ("%s %s", cmd->name, summary_translated);
  52             if (!command_help)
  53               break;
  54
  55             grub_utf8_to_ucs4_alloc (command_help, &unicode_command_help,
  56                                      &unicode_last_position);
  57
  58             FOR_ACTIVE_TERM_OUTPUTS(term)
  59             {
  60               unsigned stringwidth;
  61               grub_uint32_t *unicode_last_screen_position;
  62
  63               unicode_last_screen_position = unicode_command_help;
  64
  65               stringwidth = 0;
  66
  67               while (unicode_last_screen_position < unicode_last_position &&
  68                      stringwidth < ((grub_term_width (term) / 2) - 2))
  69                 {
  70                   struct grub_unicode_glyph glyph;
  71                   unicode_last_screen_position
  72                     += grub_unicode_aglomerate_comb (unicode_last_screen_position,
  73                                                      unicode_last_position
  74                                                      - unicode_last_screen_position,
  75                                                      &glyph);
  76
  77                   stringwidth
  78                     += grub_term_getcharwidth (term, &glyph);
  79                 }
  80
  81               grub_print_ucs4 (unicode_command_help,
  82                                unicode_last_screen_position, 0, 0, term);
  83               if (!(cnt % 2))
  84                 grub_print_spaces (term, grub_term_width (term) / 2
  85                                    - stringwidth);
  86             }
  87
  88             if (cnt % 2)
  89               grub_printf ("\n");
  90             cnt++;
  91
  92             grub_free (command_help);
  93             grub_free (unicode_command_help);
  94           }
  95       }
  96       if (!(cnt % 2))
  97         grub_printf ("\n");
  98     }
  99   else
 100     {
 101       int i;
 102       grub_command_t cmd;
 103
 104       for (i = 0; i < argc; i++)
 105         {
 106           currarg = args[i];
 107           FOR_COMMANDS(cmd)
 108           {
 109             if (cmd->prio & GRUB_PRIO_LIST_FLAG_ACTIVE)
 110               {
 111                 if (! grub_strncmp (cmd->name, currarg, grub_strlen (currarg)))
 112                   {
 113                     if (cnt++ > 0)
 114                       grub_printf ("\n\n");
 115
 116                     if ((cmd->flags & GRUB_COMMAND_FLAG_EXTCMD) &&
 117                         ! (cmd->flags & GRUB_COMMAND_FLAG_DYNCMD))
 118                       grub_arg_show_help ((grub_extcmd_t) cmd->data);
 119                     else
 120                       grub_printf ("%s %s %s\n%s\n", _("Usage:"), cmd->name, _(cmd->summary),
 121                                    _(cmd->description));
 122                   }
 123               }
 124           }
 125         }
 126     }
 127
 128   return 0;
 129 }
 130
 131 static grub_extcmd_t cmd;
 132 \f
 133 GRUB_MOD_INIT(help)
 134 {
 135   cmd = grub_register_extcmd ("help", grub_cmd_help, 0,
 136                               N_("[PATTERN ...]"),
 137                               N_("Show a help message."), 0);
 138 }
 139
 140 GRUB_MOD_FINI(help)
 141 {
 142   grub_unregister_extcmd (cmd);
 143 }