244 lines
6 KiB
C
244 lines
6 KiB
C
/* loopback.c - command to add loopback devices. */
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2005,2006,2007 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <grub/dl.h>
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#include <grub/misc.h>
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#include <grub/file.h>
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#include <grub/disk.h>
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#include <grub/mm.h>
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#include <grub/extcmd.h>
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#include <grub/i18n.h>
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struct grub_loopback
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{
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char *devname;
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grub_file_t file;
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int has_partitions;
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struct grub_loopback *next;
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};
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static struct grub_loopback *loopback_list;
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static const struct grub_arg_option options[] =
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{
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{"delete", 'd', 0, N_("Delete the loopback device entry."), 0, 0},
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{"partitions", 'p', 0, N_("Simulate a hard drive with partitions."), 0, 0},
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{0, 0, 0, 0, 0, 0}
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};
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/* Delete the loopback device NAME. */
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static grub_err_t
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delete_loopback (const char *name)
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{
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struct grub_loopback *dev;
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struct grub_loopback **prev;
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/* Search for the device. */
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for (dev = loopback_list, prev = &loopback_list;
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dev;
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prev = &dev->next, dev = dev->next)
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if (grub_strcmp (dev->devname, name) == 0)
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break;
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if (! dev)
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return grub_error (GRUB_ERR_BAD_DEVICE, "device not found");
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/* Remove the device from the list. */
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*prev = dev->next;
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grub_free (dev->devname);
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grub_file_close (dev->file);
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grub_free (dev);
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return 0;
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}
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/* The command to add and remove loopback devices. */
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static grub_err_t
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grub_cmd_loopback (grub_extcmd_context_t ctxt, int argc, char **args)
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{
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struct grub_arg_list *state = ctxt->state;
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grub_file_t file;
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struct grub_loopback *newdev;
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grub_err_t ret;
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if (argc < 1)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "device name required");
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/* Check if `-d' was used. */
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if (state[0].set)
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return delete_loopback (args[0]);
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if (argc < 2)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "file name required");
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file = grub_file_open (args[1]);
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if (! file)
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return grub_errno;
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/* First try to replace the old device. */
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for (newdev = loopback_list; newdev; newdev = newdev->next)
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if (grub_strcmp (newdev->devname, args[0]) == 0)
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break;
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if (newdev)
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{
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char *newname = grub_strdup (args[1]);
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if (! newname)
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goto fail;
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grub_file_close (newdev->file);
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newdev->file = file;
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/* Set has_partitions when `--partitions' was used. */
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newdev->has_partitions = state[1].set;
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return 0;
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}
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/* Unable to replace it, make a new entry. */
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newdev = grub_malloc (sizeof (struct grub_loopback));
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if (! newdev)
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goto fail;
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newdev->devname = grub_strdup (args[0]);
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if (! newdev->devname)
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{
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grub_free (newdev);
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goto fail;
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}
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newdev->file = file;
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/* Set has_partitions when `--partitions' was used. */
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newdev->has_partitions = state[1].set;
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/* Add the new entry to the list. */
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newdev->next = loopback_list;
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loopback_list = newdev;
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return 0;
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fail:
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ret = grub_errno;
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grub_file_close (file);
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return ret;
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}
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static int
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grub_loopback_iterate (int (*hook) (const char *name))
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{
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struct grub_loopback *d;
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for (d = loopback_list; d; d = d->next)
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{
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if (hook (d->devname))
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return 1;
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}
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return 0;
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}
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static grub_err_t
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grub_loopback_open (const char *name, grub_disk_t disk)
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{
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struct grub_loopback *dev;
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for (dev = loopback_list; dev; dev = dev->next)
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if (grub_strcmp (dev->devname, name) == 0)
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break;
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if (! dev)
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return grub_error (GRUB_ERR_UNKNOWN_DEVICE, "can't open device");
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/* Use the filesize for the disk size, round up to a complete sector. */
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if (dev->file->size != GRUB_FILE_SIZE_UNKNOWN)
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disk->total_sectors = ((dev->file->size + GRUB_DISK_SECTOR_SIZE - 1)
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/ GRUB_DISK_SECTOR_SIZE);
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else
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disk->total_sectors = GRUB_DISK_SIZE_UNKNOWN;
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disk->id = (unsigned long) dev;
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disk->has_partitions = dev->has_partitions;
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disk->data = dev->file;
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return 0;
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}
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static grub_err_t
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grub_loopback_read (grub_disk_t disk, grub_disk_addr_t sector,
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grub_size_t size, char *buf)
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{
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grub_file_t file = (grub_file_t) disk->data;
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grub_off_t pos;
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grub_file_seek (file, sector << GRUB_DISK_SECTOR_BITS);
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grub_file_read (file, buf, size << GRUB_DISK_SECTOR_BITS);
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if (grub_errno)
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return grub_errno;
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/* In case there is more data read than there is available, in case
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of files that are not a multiple of GRUB_DISK_SECTOR_SIZE, fill
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the rest with zeros. */
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pos = (sector + size) << GRUB_DISK_SECTOR_BITS;
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if (pos > file->size)
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{
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grub_size_t amount = pos - file->size;
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grub_memset (buf + (size << GRUB_DISK_SECTOR_BITS) - amount, 0, amount);
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}
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return 0;
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}
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static grub_err_t
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grub_loopback_write (grub_disk_t disk __attribute ((unused)),
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grub_disk_addr_t sector __attribute ((unused)),
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grub_size_t size __attribute ((unused)),
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const char *buf __attribute ((unused)))
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{
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return GRUB_ERR_NOT_IMPLEMENTED_YET;
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}
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static struct grub_disk_dev grub_loopback_dev =
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{
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.name = "loopback",
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.id = GRUB_DISK_DEVICE_LOOPBACK_ID,
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.iterate = grub_loopback_iterate,
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.open = grub_loopback_open,
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.read = grub_loopback_read,
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.write = grub_loopback_write,
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.next = 0
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};
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static grub_extcmd_t cmd;
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GRUB_MOD_INIT(loopback)
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{
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cmd = grub_register_extcmd ("loopback", grub_cmd_loopback,
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GRUB_COMMAND_FLAG_BOTH,
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N_("[-d|-p] DEVICENAME FILE."),
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N_("Make a device of a file."), options);
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grub_disk_dev_register (&grub_loopback_dev);
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}
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GRUB_MOD_FINI(loopback)
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{
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grub_unregister_extcmd (cmd);
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grub_disk_dev_unregister (&grub_loopback_dev);
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}
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