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