merge with mainline

grub-core/disk/loopback.c

@@ -0,0 +1,241 @@
+/* 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/extcmd.h>
+#include <grub/i18n.h>
+
+struct grub_loopback
+{
+  char *devname;
+  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_free (dev->devname);
+  grub_file_close (dev->file);
+  grub_free (dev);
+
+  return 0;
+}
+
+/* The command to add and remove loopback devices.  */
+static grub_err_t
+grub_cmd_loopback (grub_extcmd_context_t ctxt, int argc, char **args)
+{
+  struct grub_arg_list *state = ctxt->state;
+  grub_file_t file;
+  struct grub_loopback *newdev;
+  grub_err_t ret;
+
+  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;
+
+  /* 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)
+    {
+      char *newname = grub_strdup (args[1]);
+      if (! newname)
+	goto fail;
+
+      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)
+    {
+      grub_free (newdev);
+      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:
+  ret = grub_errno;
+  grub_file_close (file);
+  return ret;
+}
+
+
+static int
+grub_loopback_iterate (int (*hook) (const char *name))
+{
+  struct grub_loopback *d;
+  for (d = loopback_list; d; d = d->next)
+    {
+      if (hook (d->devname))
+	return 1;
+    }
+  return 0;
+}
+
+static grub_err_t
+grub_loopback_open (const char *name, grub_disk_t disk)
+{
+  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");
+
+  /* Use the filesize for the disk size, round up to a complete sector.  */
+  disk->total_sectors = ((dev->file->size + GRUB_DISK_SECTOR_SIZE - 1)
+			 / GRUB_DISK_SECTOR_SIZE);
+  disk->id = (unsigned long) dev;
+
+  disk->has_partitions = dev->has_partitions;
+  disk->data = dev->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 __attribute ((unused)),
+		     grub_disk_addr_t sector __attribute ((unused)),
+		     grub_size_t size __attribute ((unused)),
+		     const char *buf __attribute ((unused)))
+{
+  return GRUB_ERR_NOT_IMPLEMENTED_YET;
+}
+
+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);
+}