grub/grub-core/fs/cpio_common.c

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/* cpio.c - cpio and tar filesystem. */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2007,2008,2009,2013 Free Software Foundation, Inc.
*
* This program 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.
*
* 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/file.h>
#include <grub/mm.h>
#include <grub/misc.h>
#include <grub/disk.h>
#include <grub/dl.h>
#include <grub/i18n.h>
#include <grub/archelp.h>
GRUB_MOD_LICENSE ("GPLv3+");
struct grub_archelp_data
{
grub_disk_t disk;
grub_off_t hofs;
grub_off_t next_hofs;
grub_off_t dofs;
grub_off_t size;
};
static grub_err_t
grub_cpio_find_file (struct grub_archelp_data *data, char **name,
grub_int32_t *mtime, grub_uint32_t *mode)
{
struct head hd;
grub_size_t namesize;
grub_uint32_t modeval;
data->hofs = data->next_hofs;
if (grub_disk_read (data->disk, 0, data->hofs, sizeof (hd), &hd))
return grub_errno;
if (grub_memcmp (hd.magic, MAGIC, sizeof (hd.magic)) != 0
#ifdef MAGIC2
&& grub_memcmp (hd.magic, MAGIC2, sizeof (hd.magic)) != 0
#endif
)
return grub_error (GRUB_ERR_BAD_FS, "invalid cpio archive");
data->size = read_number (hd.filesize, ARRAY_SIZE (hd.filesize));
if (mtime)
*mtime = read_number (hd.mtime, ARRAY_SIZE (hd.mtime));
modeval = read_number (hd.mode, ARRAY_SIZE (hd.mode));
namesize = read_number (hd.namesize, ARRAY_SIZE (hd.namesize));
/* Don't allow negative numbers. */
if (namesize >= 0x80000000)
{
/* Probably a corruption, don't attempt to recover. */
*mode = GRUB_ARCHELP_ATTR_END;
return GRUB_ERR_NONE;
}
if (mode)
*mode = modeval;
*name = grub_malloc (namesize + 1);
if (*name == NULL)
return grub_errno;
if (grub_disk_read (data->disk, 0, data->hofs + sizeof (hd),
namesize, *name))
{
grub_free (*name);
return grub_errno;
}
(*name)[namesize] = 0;
if (data->size == 0 && modeval == 0 && namesize == 11
&& grub_memcmp(*name, "TRAILER!!!", 11) == 0)
{
*mode = GRUB_ARCHELP_ATTR_END;
grub_free (*name);
return GRUB_ERR_NONE;
}
data->dofs = data->hofs + ALIGN_CPIO (sizeof (hd) + namesize);
data->next_hofs = data->dofs + ALIGN_CPIO (data->size);
return GRUB_ERR_NONE;
}
static char *
grub_cpio_get_link_target (struct grub_archelp_data *data)
{
char *ret;
grub_err_t err;
if (data->size == 0)
return grub_strdup ("");
ret = grub_malloc (data->size + 1);
if (!ret)
return NULL;
err = grub_disk_read (data->disk, 0, data->dofs, data->size,
ret);
if (err)
{
grub_free (ret);
return NULL;
}
ret[data->size] = '\0';
return ret;
}
static void
grub_cpio_rewind (struct grub_archelp_data *data)
{
data->next_hofs = 0;
}
static struct grub_archelp_ops arcops =
{
.find_file = grub_cpio_find_file,
.get_link_target = grub_cpio_get_link_target,
.rewind = grub_cpio_rewind
};
static struct grub_archelp_data *
grub_cpio_mount (grub_disk_t disk)
{
struct head hd;
struct grub_archelp_data *data;
if (grub_disk_read (disk, 0, 0, sizeof (hd), &hd))
goto fail;
if (grub_memcmp (hd.magic, MAGIC, sizeof (MAGIC) - 1)
#ifdef MAGIC2
&& grub_memcmp (hd.magic, MAGIC2, sizeof (MAGIC2) - 1)
#endif
)
goto fail;
data = (struct grub_archelp_data *) grub_zalloc (sizeof (*data));
if (!data)
goto fail;
data->disk = disk;
return data;
fail:
grub_error (GRUB_ERR_BAD_FS, "not a " FSNAME " filesystem");
return 0;
}
static grub_err_t
grub_cpio_dir (grub_device_t device, const char *path_in,
grub_fs_dir_hook_t hook, void *hook_data)
{
struct grub_archelp_data *data;
grub_err_t err;
data = grub_cpio_mount (device->disk);
if (!data)
return grub_errno;
err = grub_archelp_dir (data, &arcops,
path_in, hook, hook_data);
grub_free (data);
return err;
}
static grub_err_t
grub_cpio_open (grub_file_t file, const char *name_in)
{
struct grub_archelp_data *data;
grub_err_t err;
data = grub_cpio_mount (file->device->disk);
if (!data)
return grub_errno;
err = grub_archelp_open (data, &arcops, name_in);
if (err)
{
grub_free (data);
}
else
{
file->data = data;
file->size = data->size;
}
return err;
}
static grub_ssize_t
grub_cpio_read (grub_file_t file, char *buf, grub_size_t len)
{
struct grub_archelp_data *data;
grub_ssize_t ret;
data = file->data;
data->disk->read_hook = file->read_hook;
data->disk->read_hook_data = file->read_hook_data;
ret = (grub_disk_read (data->disk, 0, data->dofs + file->offset,
len, buf)) ? -1 : (grub_ssize_t) len;
data->disk->read_hook = 0;
return ret;
}
static grub_err_t
grub_cpio_close (grub_file_t file)
{
struct grub_archelp_data *data;
data = file->data;
grub_free (data);
return grub_errno;
}
static struct grub_fs grub_cpio_fs = {
.name = FSNAME,
.dir = grub_cpio_dir,
.open = grub_cpio_open,
.read = grub_cpio_read,
.close = grub_cpio_close,
#ifdef GRUB_UTIL
.reserved_first_sector = 0,
.blocklist_install = 0,
#endif
};