On 02.12.2011 07:05, Vladimir Serbinenko wrote:
P.S. Do you know if there are any plans in the future to implement
write operations for filesystems? (I noticed raw disk writing is
currently supported.) If not, is the reason due to the technical
challenges (e.g. NTFS only had read-only access in GNU/Linux for quite
a while) or just a general lack of interest?
Neither. Reliability concerns. Writing to filesystem is potentially
dangerous and needs to be throughly tested. Since writing is rare for
bootloader we won't receive enough testing of these code pathes so every
write will remain a risk. We can't have such risks
I see. Just curious.
Thanks for this. However the coding style isn't according to our
standards. Could you adjust to the standard? I recommend looking at
other code and reading GNU Coding Standard. E.g. we don't use {0}
initialiser, return value of commands, C++ comments or M$-$tyle
variables.
Sorry about that. I've reviewed the standard and perused the source
tree, as you suggested, to determine the best style. Attached is my
updated file.
Much better. There are still few problems like the arbitrary limit (we
avoid any arbitrary limits, you have one easy to avoid on filename
length). Also we don't use such ABORT macros as they offer no
readability advantage. Review in more details when time permits.
Argh. I remember reading about avoiding arbitrary limits too.
I would contend that in this case the macros do improve readability (each
reducing 4-5 lines of code down to 1-2 lines); yet, to be consistent with the
rest of the source base, I've removed them.
Here's the file again. Maybe the third time's the charm?
Thanks for being a stickler for conformance ( I mean it :) ),
Peter Lustig
/* nthibr.c - tests whether an MS Windows system partition is hibernated */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2007,2008,2009,2011 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 3 of the License, or
* (at your option) any later version.
*
* GRUB 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, see <http://www.gnu.org/licenses/>.
*/
#include <grub/types.h>
#include <grub/mm.h>
#include <grub/disk.h>
#include <grub/file.h>
#include <grub/misc.h>
#include <grub/dl.h>
#include <grub/extcmd.h>
#include <grub/lib/arg.h>
#include <grub/err.h>
#include <grub/i18n.h>
GRUB_MOD_LICENSE("GPLv3+");
/* Define this 'empty' array to let the '-h' and '-u' switches be processed */
static const struct grub_arg_option options[] = {
{0, 0, 0, 0, 0, 0}
};
static grub_err_t
grub_cmd_nthibr (grub_extcmd_context_t ctxt __attribute__ ((unused)),
int argc, char **args)
{
grub_err_t status = GRUB_ERR_NONE;
char *partition_name, *hibr_file_path = 0, hibr_file_magic[5];
grub_size_t name_length;
grub_ssize_t magic_size;
grub_disk_t partition;
grub_file_t hibr_file = 0;
/* Check argument count */
if (!argc)
{
status = grub_error (GRUB_ERR_BAD_ARGUMENT,
N_("too few arguments specified"));
goto exit;
}
else if (argc > 1)
{
status = grub_error (GRUB_ERR_BAD_ARGUMENT,
N_("too many arguments specified"));
goto exit;
}
partition_name = args[0];
name_length = grub_strlen (partition_name);
/* Check if partition specifier 'looks right' */
if (partition_name[0] != '(' || partition_name[name_length - 1] != ')')
{
status = grub_error (GRUB_ERR_BAD_FILENAME,
N_("invalid partition specifier"));
goto exit;
}
/* Check if partition actually exists */
partition_name[name_length - 1] = '\0';
partition = grub_disk_open (partition_name + 1);
if (!partition)
{
status = grub_error (GRUB_ERR_UNKNOWN_DEVICE,
N_("partition not found"));
goto exit;
}
else
{
grub_disk_close (partition);
partition_name[name_length - 1] = ')';
}
/* Build path to 'hiberfil.sys' */
hibr_file_path = grub_malloc (grub_strlen (partition_name)
+ grub_strlen ("/hiberfil.sys") + 1);
if (!hibr_file_path)
{
status = grub_error (GRUB_ERR_OUT_OF_MEMORY,
N_("out of memory"));
goto exit;
}
else
{
grub_strcpy (hibr_file_path, partition_name);
grub_strcat (hibr_file_path, "/hiberfil.sys");
}
/* Try to open 'hiberfil.sys' */
hibr_file = grub_file_open (hibr_file_path);
if (!hibr_file)
{
status = grub_error (GRUB_ERR_FILE_NOT_FOUND,
N_("'hiberfil.sys' not found"));
goto exit;
}
/* Try to read magic number of 'hiberfil.sys' */
magic_size = sizeof (hibr_file_magic) - 1;
grub_memset (hibr_file_magic, 0, sizeof (hibr_file_magic));
if (grub_file_read (hibr_file, hibr_file_magic, magic_size) < magic_size)
{
status = grub_error (GRUB_ERR_BAD_FILE_TYPE,
N_("'hiberfil.sys' too small"));
goto exit;
}
/* Return SUCCESS if magic indicates file is active; else return FAILURE */
if (!grub_strncasecmp ("hibr", hibr_file_magic, magic_size))
grub_puts (N_("The system is hibernated."));
else
{
grub_puts (N_("The system is NOT hibernated."));
status = GRUB_ERR_TEST_FAILURE;
}
exit:
/* Ensure unmanaged resources are cleaned up */
if (hibr_file_path)
grub_free (hibr_file_path);
if (hibr_file)
grub_file_close (hibr_file);
return status;
}
static grub_extcmd_t cmd;
GRUB_MOD_INIT (nthibr)
{
cmd = grub_register_extcmd ("nthibr", grub_cmd_nthibr, 0,
N_("DEVICE"),
N_("Test whether an NT system partition "
"is hibernated."),
options);
}
GRUB_MOD_FINI (nthibr)
{
grub_unregister_extcmd (cmd);
}
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