test -e command for grub2

test -e command for grub2

[adrian15]

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I attach then new test.c for grub2. (I worked from Grub 1.94 version).

It only implements the test -e feature.
I haven't been able to check it. ./configure says something about a LZO
version.

1) Why cat uses the file = grub_gzfile_open (args[0], 1); sentence to
check if a file can be opened or not? Is it cat supposed to cat also
gzipped files?

Is it better for me to use grub_gzfile_open on my test command?

2) I've done this:

static const struct grub_arg_option options[] =
    {
      {"file", 'e', 0, "test if a file exists", 0, 0},
      {0, 0, 0, 0, 0, 0}
    };

copying-pasting from search.c but I do not understand it too much... if
this is repeated in test.c and search.c the compiler should complain...
isn't it ?

3) And you're free to tell to only attach patchs instead of the full 
file... and you're free to tell me an url for a gnu c syntax or 
convention as far as I do not know if the gnu project has any. And, of 
course, tell me if it compiles or not.

adrian15

P.S.: I am going to update from Knoppix 4 to Knoppix 5 soon and I think 
I won't hae the lzo problem.

[-- Attachment #2: test.c --]
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/* test.c -- The test command..  */
/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 2005  Free Software Foundation, Inc.
 *
 *  GRUB is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with GRUB; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <grub/normal.h>
#include <grub/dl.h>
#include <grub/arg.h>
#include <grub/misc.h>
#include <grub/mm.h>
#include <grub/env.h>


static void
test_file_exists (const char *key, const char *var)
{
	char *p;

	grub_file_t file;

      file = grub_file_open (key);
      if (file)
	{
	  grub_printf (" %s", key);
	  grub_file_close (file);
	  grub_errno = GRUB_ERR_NONE;
	  return 0;
	}
      else
	{
	  grub_error (GRUB_ERR_FILE_NOT_FOUND, "File does not exists.");
	}
}


static const struct grub_arg_option options[] =
  {
    {"file", 'e', 0, "test if a file exists", 0, 0},
    {0, 0, 0, 0, 0, 0}
  };

static grub_err_t
grub_cmd_test (struct grub_arg_list *state, int argc, char **args)
{
  const char *var = 0;
  
  if (argc == 0)
    return grub_error (GRUB_ERR_INVALID_COMMAND, "no argument specified");

  if (state[0].set)
    test_file_exists (args[0], var);

  return grub_errno;
}

\f
GRUB_MOD_INIT(test)
{
  (void)mod;			/* To stop warning. */
  grub_register_command ("[", grub_cmd_test, GRUB_COMMAND_FLAG_CMDLINE,
			 "[ EXPRESSION ]", "Evaluate an expression", 0);
  grub_register_command ("test", grub_cmd_test, GRUB_COMMAND_FLAG_CMDLINE,
			 "test EXPRESSION", "Evaluate an expression", 0);
}

GRUB_MOD_FINI(test)
{
  grub_unregister_command ("[");
  grub_unregister_command ("test");
}

Re: test -e command for grub2

[Hollis Blanchard]

On Tue, 2006-06-13 at 15:00 +0200, adrian15 wrote:
> I attach then new test.c for grub2. (I worked from Grub 1.94 version).
> 
> It only implements the test -e feature.
> I haven't been able to check it. ./configure says something about a LZO
> version.

You haven't even compiled it? Perhaps you should install the LZO
libraries you need.

> 1) Why cat uses the file = grub_gzfile_open (args[0], 1); sentence to
> check if a file can be opened or not? Is it cat supposed to cat also
> gzipped files?

I guess so.

> Is it better for me to use grub_gzfile_open on my test command?

Probably not, since you're just testing for existence.

> 2) I've done this:
> 
> static const struct grub_arg_option options[] =
>     {
>       {"file", 'e', 0, "test if a file exists", 0, 0},
>       {0, 0, 0, 0, 0, 0}
>     };
> 
> copying-pasting from search.c but I do not understand it too much... if
> this is repeated in test.c and search.c the compiler should complain...
> isn't it ?

No, it's static.

> 3) And you're free to tell to only attach patchs instead of the full 
> file... and you're free to tell me an url for a gnu c syntax or 
> convention as far as I do not know if the gnu project has any. And, of 
> course, tell me if it compiles or not.

Google for GNU Coding Style. Then, since that document is incomplete,
you will need to mimic the style you see elsewhere in GRUB.

> P.S.: I am going to update from Knoppix 4 to Knoppix 5 soon and I think 
> I won't hae the lzo problem.

Try installing the LZO development package on Knoppix 4.

-Hollis