GRUB2/MOD_SRC/grub-2.04/grub-core/commands/echo.c

   1 /* echo.c - Command to display a line of text  */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2006,2007,2010  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/extcmd.h>
  23 #include <grub/i18n.h>
  24 #include <grub/term.h>
  25
  26 GRUB_MOD_LICENSE ("GPLv3+");
  27
  28 extern const char *ventoy_get_vmenu_title(const char *vMenu);
  29
  30 static const struct grub_arg_option options[] =
  31   {
  32     {0, 'n', 0, N_("Do not output the trailing newline."), 0, 0},
  33     {0, 'e', 0, N_("Enable interpretation of backslash escapes."), 0, 0},
  34     {0, 'v', 0, N_("ventoy menu language."), 0, 0},
  35     {0, 'V', 0, N_("ventoy menu language with pre-newline."), 0, 0},
  36     {0, 0, 0, 0, 0, 0}
  37   };
  38
  39 static grub_err_t
  40 grub_cmd_echo (grub_extcmd_context_t ctxt, int argc, char **args)
  41 {
  42   struct grub_arg_list *state = ctxt->state;
  43   char ch;
  44   int vtmenu = 0;
  45   int newline = 1;
  46   int i;
  47
  48   /* Check if `-n' was used.  */
  49   if (state[0].set)
  50     newline = 0;
  51
  52   if (state[2].set || state[3].set)
  53     vtmenu = 1;
  54
  55   for (i = 0; i < argc; i++)
  56     {
  57       char *arg = *args;
  58       /* Unescaping results in a string no longer than the original.  */
  59       char *unescaped = grub_malloc (grub_strlen (arg) + 1);
  60       char *p = unescaped;
  61       args++;
  62
  63       if (!unescaped)
  64         return grub_errno;
  65
  66       while (*arg)
  67         {
  68           /* In case `-e' is used, parse backslashes.  */
  69           if (*arg == '\\' && state[1].set)
  70             {
  71               arg++;
  72               if (*arg == '\0')
  73                 break;
  74
  75               switch (*arg)
  76                 {
  77                 case '\\':
  78                   *p++ = '\\';
  79                   break;
  80
  81                 case 'a':
  82                   *p++ = '\a';
  83                   break;
  84
  85                 case 'c':
  86                   newline = 0;
  87                   break;
  88
  89                 case 'f':
  90                   *p++ = '\f';
  91                   break;
  92
  93                 case 'n':
  94                   *p++ = '\n';
  95                   break;
  96
  97                 case 'r':
  98                   *p++ = '\r';
  99                   break;
 100
 101                 case 't':
 102                   *p++ = '\t';
 103                   break;
 104
 105                 case 'v':
 106                   *p++ = '\v';
 107                   break;
 108                 }
 109               arg++;
 110               continue;
 111             }
 112
 113           /* This was not an escaped character, or escaping is not
 114              enabled.  */
 115           *p++ = *arg;
 116           arg++;
 117         }
 118
 119       *p = '\0';
 120
 121     if (vtmenu && grub_strncmp(unescaped, "VTMENU_", 7) == 0)
 122     {
 123         p = unescaped;
 124         while ((*p >= 'A' && *p <= 'Z') || *p == '_')
 125         {
 126             p++;
 127         }
 128
 129         ch = *p;
 130         *p = 0;
 131         if (state[3].set)
 132         {
 133             grub_xputs("\n");
 134         }
 135         grub_xputs(ventoy_get_vmenu_title(unescaped));
 136
 137         *p = ch;
 138         grub_xputs(p);
 139     }
 140     else
 141     {
 142         grub_xputs (unescaped);
 143     }
 144
 145     grub_free (unescaped);
 146
 147     /* If another argument follows, insert a space.  */
 148     if ((0 == vtmenu) && (i != argc - 1))
 149             grub_printf (" " );
 150     }
 151
 152   if (newline)
 153     grub_printf ("\n");
 154
 155   grub_refresh ();
 156
 157   return 0;
 158 }
 159
 160 static grub_extcmd_t cmd;
 161 \f
 162 GRUB_MOD_INIT(echo)
 163 {
 164   cmd = grub_register_extcmd ("echo", grub_cmd_echo,
 165                               GRUB_COMMAND_ACCEPT_DASH
 166                               | GRUB_COMMAND_OPTIONS_AT_START,
 167                               N_("[-e|-n] STRING"), N_("Display a line of text."),
 168                               options);
 169 }
 170
 171 GRUB_MOD_FINI(echo)
 172 {
 173   grub_unregister_extcmd (cmd);
 174 }