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- /* loopback.c - command to add loopback devices. */
- /*
- * GRUB -- GRand Unified Bootloader
- * Copyright (C) 2005,2006,2007 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/dl.h>
- #include <grub/misc.h>
- #include <grub/file.h>
- #include <grub/disk.h>
- #include <grub/mm.h>
- #include <grub/env.h>
- #include <grub/extcmd.h>
- #include <grub/i18n.h>
- struct grub_loopback
- {
- char *devname;
- char *filename;
- grub_file_t file;
- int has_partitions;
- struct grub_loopback *next;
- };
- static struct grub_loopback *loopback_list;
- static const struct grub_arg_option options[] =
- {
- {"delete", 'd', 0, N_("Delete the loopback device entry."), 0, 0},
- {"partitions", 'p', 0, N_("Simulate a hard drive with partitions."), 0, 0},
- {0, 0, 0, 0, 0, 0}
- };
- /* Delete the loopback device NAME. */
- static grub_err_t
- delete_loopback (const char *name)
- {
- struct grub_loopback *dev;
- struct grub_loopback **prev;
- /* Search for the device. */
- for (dev = loopback_list, prev = &loopback_list;
- dev;
- prev = &dev->next, dev = dev->next)
- if (grub_strcmp (dev->devname, name) == 0)
- break;
- if (! dev)
- return grub_error (GRUB_ERR_BAD_DEVICE, "device not found");
- /* Remove the device from the list. */
- *prev = dev->next;
- grub_file_close (dev->file);
- grub_free (dev->devname);
- grub_free (dev);
- return 0;
- }
- /* The command to add and remove loopback devices. */
- static grub_err_t
- grub_cmd_loopback (grub_extcmd_t cmd, int argc, char **args)
- {
- struct grub_arg_list *state = state = cmd->state;
- grub_file_t file;
- struct grub_loopback *newdev;
- if (argc < 1)
- return grub_error (GRUB_ERR_BAD_ARGUMENT, "device name required");
- /* Check if `-d' was used. */
- if (state[0].set)
- return delete_loopback (args[0]);
- if (argc < 2)
- return grub_error (GRUB_ERR_BAD_ARGUMENT, "file name required");
- file = grub_file_open (args[1]);
- if (! file)
- return grub_errno;
- grub_blocklist_convert (file);
- /* First try to replace the old device. */
- for (newdev = loopback_list; newdev; newdev = newdev->next)
- if (grub_strcmp (newdev->devname, args[0]) == 0)
- break;
- if (newdev)
- {
- grub_file_close (newdev->file);
- newdev->file = file;
- /* Set has_partitions when `--partitions' was used. */
- newdev->has_partitions = state[1].set;
- return 0;
- }
- /* Unable to replace it, make a new entry. */
- newdev = grub_malloc (sizeof (struct grub_loopback));
- if (! newdev)
- goto fail;
- newdev->devname = grub_strdup (args[0]);
- if (! newdev->devname)
- goto fail;
- newdev->file = file;
- /* Set has_partitions when `--partitions' was used. */
- newdev->has_partitions = state[1].set;
- /* Add the new entry to the list. */
- newdev->next = loopback_list;
- loopback_list = newdev;
- return 0;
- fail:
- grub_free (newdev);
- grub_file_close (file);
- return grub_errno;
- }
- static int
- grub_loopback_iterate (int (*hook) (const char *name, void *closure),
- void *closure)
- {
- struct grub_loopback *d;
- for (d = loopback_list; d; d = d->next)
- {
- if (hook (d->devname, closure))
- return 1;
- }
- return 0;
- }
- static grub_err_t
- grub_loopback_open (const char *name, grub_disk_t disk)
- {
- grub_file_t file;
- struct grub_loopback *dev;
- for (dev = loopback_list; dev; dev = dev->next)
- if (grub_strcmp (dev->devname, name) == 0)
- break;
- if (! dev)
- return grub_error (GRUB_ERR_UNKNOWN_DEVICE, "can't open device");
- file = dev->file;
- /* Use the filesize for the disk size, round up to a complete sector. */
- disk->total_sectors = ((file->size + GRUB_DISK_SECTOR_SIZE - 1)
- / GRUB_DISK_SECTOR_SIZE);
- disk->id = (unsigned long) dev;
- disk->has_partitions = dev->has_partitions;
- disk->data = file;
- return 0;
- }
- static grub_err_t
- grub_loopback_read (grub_disk_t disk, grub_disk_addr_t sector,
- grub_size_t size, char *buf)
- {
- grub_file_t file = (grub_file_t) disk->data;
- grub_off_t pos;
- grub_file_seek (file, sector << GRUB_DISK_SECTOR_BITS);
- grub_file_read (file, buf, size << GRUB_DISK_SECTOR_BITS);
- if (grub_errno)
- return grub_errno;
- /* In case there is more data read than there is available, in case
- of files that are not a multiple of GRUB_DISK_SECTOR_SIZE, fill
- the rest with zeros. */
- pos = (sector + size) << GRUB_DISK_SECTOR_BITS;
- if (pos > file->size)
- {
- grub_size_t amount = pos - file->size;
- grub_memset (buf + (size << GRUB_DISK_SECTOR_BITS) - amount, 0, amount);
- }
- return 0;
- }
- static grub_err_t
- grub_loopback_write (grub_disk_t disk, grub_disk_addr_t sector,
- grub_size_t size, const char *buf)
- {
- grub_file_t file = (grub_file_t) disk->data;
- grub_file_seek (file, sector << GRUB_DISK_SECTOR_BITS);
- return (grub_blocklist_write (file, buf,
- size << GRUB_DISK_SECTOR_BITS) >= 0) ?
- grub_errno :
- grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, "write operation not supported");
- }
- static struct grub_disk_dev grub_loopback_dev =
- {
- .name = "loopback",
- .id = GRUB_DISK_DEVICE_LOOPBACK_ID,
- .iterate = grub_loopback_iterate,
- .open = grub_loopback_open,
- .read = grub_loopback_read,
- .write = grub_loopback_write,
- .next = 0
- };
- static grub_extcmd_t cmd;
- GRUB_MOD_INIT(loopback)
- {
- cmd = grub_register_extcmd ("loopback", grub_cmd_loopback,
- GRUB_COMMAND_FLAG_BOTH,
- N_("[-d|-p] DEVICENAME FILE."),
- N_("Make a device of a file."), options);
- grub_disk_dev_register (&grub_loopback_dev);
- }
- GRUB_MOD_FINI(loopback)
- {
- grub_unregister_extcmd (cmd);
- grub_disk_dev_unregister (&grub_loopback_dev);
- }
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