block/raw_bsd.c - qemu - Git at Google

 /* BlockDriver implementation for "raw"
  *
  * Copyright (C) 2010, 2013, Red Hat, Inc.
  * Copyright (C) 2010, Blue Swirl <blauwirbel@gmail.com>
  * Copyright (C) 2009, Anthony Liguori <aliguori@us.ibm.com>
  *
  * Author:
  *   Laszlo Ersek <lersek@redhat.com>
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to
  * deal in the Software without restriction, including without limitation the
  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
  * sell copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  * IN THE SOFTWARE.
  */

 #include "qemu/osdep.h"
 #include "block/block_int.h"
 #include "qemu/option.h"

 static QemuOptsList raw_create_opts = {
     .name = "raw-create-opts",
     .head = QTAILQ_HEAD_INITIALIZER(raw_create_opts.head),
     .desc = {
         {
             .name = BLOCK_OPT_SIZE,
             .type = QEMU_OPT_SIZE,
             .help = "Virtual disk size"
         },
         { /* end of list */ }
     }
 };

 static int raw_reopen_prepare(BDRVReopenState *reopen_state,
                               BlockReopenQueue *queue, Error **errp)
 {
     return 0;
 }

 static int coroutine_fn raw_co_readv(BlockDriverState *bs, int64_t sector_num,
                                      int nb_sectors, QEMUIOVector *qiov)
 {
     BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
     return bdrv_co_readv(bs->file->bs, sector_num, nb_sectors, qiov);
 }

 static int coroutine_fn raw_co_writev(BlockDriverState *bs, int64_t sector_num,
                                       int nb_sectors, QEMUIOVector *qiov)
 {
     void *buf = NULL;
     BlockDriver *drv;
     QEMUIOVector local_qiov;
     int ret;

     if (bs->probed && sector_num == 0) {
         /* As long as these conditions are true, we can't get partial writes to
          * the probe buffer and can just directly check the request. */
         QEMU_BUILD_BUG_ON(BLOCK_PROBE_BUF_SIZE != 512);
         QEMU_BUILD_BUG_ON(BDRV_SECTOR_SIZE != 512);

         if (nb_sectors == 0) {
             /* qemu_iovec_to_buf() would fail, but we want to return success
              * instead of -EINVAL in this case. */
             return 0;
         }

         buf = qemu_try_blockalign(bs->file->bs, 512);
         if (!buf) {
             ret = -ENOMEM;
             goto fail;
         }

         ret = qemu_iovec_to_buf(qiov, 0, buf, 512);
         if (ret != 512) {
             ret = -EINVAL;
             goto fail;
         }

         drv = bdrv_probe_all(buf, 512, NULL);
         if (drv != bs->drv) {
             ret = -EPERM;
             goto fail;
         }

         /* Use the checked buffer, a malicious guest might be overwriting its
          * original buffer in the background. */
         qemu_iovec_init(&local_qiov, qiov->niov + 1);
         qemu_iovec_add(&local_qiov, buf, 512);
         qemu_iovec_concat(&local_qiov, qiov, 512, qiov->size - 512);
         qiov = &local_qiov;
     }

     BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
     ret = bdrv_co_writev(bs->file->bs, sector_num, nb_sectors, qiov);

 fail:
     if (qiov == &local_qiov) {
         qemu_iovec_destroy(&local_qiov);
     }
     qemu_vfree(buf);
     return ret;
 }

 static int64_t coroutine_fn raw_co_get_block_status(BlockDriverState *bs,
                                             int64_t sector_num,
                                             int nb_sectors, int *pnum,
                                             BlockDriverState **file)
 {
     *pnum = nb_sectors;
     *file = bs->file->bs;
     return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID | BDRV_BLOCK_DATA |
            (sector_num << BDRV_SECTOR_BITS);
 }

 static int coroutine_fn raw_co_write_zeroes(BlockDriverState *bs,
                                             int64_t sector_num, int nb_sectors,
                                             BdrvRequestFlags flags)
 {
     return bdrv_co_write_zeroes(bs->file->bs, sector_num, nb_sectors, flags);
 }

 static int coroutine_fn raw_co_discard(BlockDriverState *bs,
                                        int64_t sector_num, int nb_sectors)
 {
     return bdrv_co_discard(bs->file->bs, sector_num, nb_sectors);
 }

 static int64_t raw_getlength(BlockDriverState *bs)
 {
     return bdrv_getlength(bs->file->bs);
 }

 static int raw_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 {
     return bdrv_get_info(bs->file->bs, bdi);
 }

 static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
 {
     bs->bl = bs->file->bs->bl;
 }

 static int raw_truncate(BlockDriverState *bs, int64_t offset)
 {
     return bdrv_truncate(bs->file->bs, offset);
 }

 static int raw_media_changed(BlockDriverState *bs)
 {
     return bdrv_media_changed(bs->file->bs);
 }

 static void raw_eject(BlockDriverState *bs, bool eject_flag)
 {
     bdrv_eject(bs->file->bs, eject_flag);
 }

 static void raw_lock_medium(BlockDriverState *bs, bool locked)
 {
     bdrv_lock_medium(bs->file->bs, locked);
 }

 static BlockAIOCB *raw_aio_ioctl(BlockDriverState *bs,
                                  unsigned long int req, void *buf,
                                  BlockCompletionFunc *cb,
                                  void *opaque)
 {
     return bdrv_aio_ioctl(bs->file->bs, req, buf, cb, opaque);
 }

 static int raw_has_zero_init(BlockDriverState *bs)
 {
     return bdrv_has_zero_init(bs->file->bs);
 }

 static int raw_create(const char *filename, QemuOpts *opts, Error **errp)
 {
     Error *local_err = NULL;
     int ret;

     ret = bdrv_create_file(filename, opts, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
     }
     return ret;
 }

 static int raw_open(BlockDriverState *bs, QDict *options, int flags,
                     Error **errp)
 {
     bs->sg = bs->file->bs->sg;

     if (bs->probed && !bdrv_is_read_only(bs)) {
         fprintf(stderr,
                 "WARNING: Image format was not specified for '%s' and probing "
                 "guessed raw.\n"
                 "         Automatically detecting the format is dangerous for "
                 "raw images, write operations on block 0 will be restricted.\n"
                 "         Specify the 'raw' format explicitly to remove the "
                 "restrictions.\n",
                 bs->file->bs->filename);
     }

     return 0;
 }

 static void raw_close(BlockDriverState *bs)
 {
 }

 static int raw_probe(const uint8_t *buf, int buf_size, const char *filename)
 {
     /* smallest possible positive score so that raw is used if and only if no
      * other block driver works
      */
     return 1;
 }

 static int raw_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz)
 {
     return bdrv_probe_blocksizes(bs->file->bs, bsz);
 }

 static int raw_probe_geometry(BlockDriverState *bs, HDGeometry *geo)
 {
     return bdrv_probe_geometry(bs->file->bs, geo);
 }

 BlockDriver bdrv_raw = {
     .format_name          = "raw",
     .bdrv_probe           = &raw_probe,
     .bdrv_reopen_prepare  = &raw_reopen_prepare,
     .bdrv_open            = &raw_open,
     .bdrv_close           = &raw_close,
     .bdrv_create          = &raw_create,
     .bdrv_co_readv        = &raw_co_readv,
     .bdrv_co_writev       = &raw_co_writev,
     .bdrv_co_write_zeroes = &raw_co_write_zeroes,
     .bdrv_co_discard      = &raw_co_discard,
     .bdrv_co_get_block_status = &raw_co_get_block_status,
     .bdrv_truncate        = &raw_truncate,
     .bdrv_getlength       = &raw_getlength,
     .has_variable_length  = true,
     .bdrv_get_info        = &raw_get_info,
     .bdrv_refresh_limits  = &raw_refresh_limits,
     .bdrv_probe_blocksizes = &raw_probe_blocksizes,
     .bdrv_probe_geometry  = &raw_probe_geometry,
     .bdrv_media_changed   = &raw_media_changed,
     .bdrv_eject           = &raw_eject,
     .bdrv_lock_medium     = &raw_lock_medium,
     .bdrv_aio_ioctl       = &raw_aio_ioctl,
     .create_opts          = &raw_create_opts,
     .bdrv_has_zero_init   = &raw_has_zero_init
 };

 static void bdrv_raw_init(void)
 {
     bdrv_register(&bdrv_raw);
 }

 block_init(bdrv_raw_init);
	/* BlockDriver implementation for "raw"
	*
	* Copyright (C) 2010, 2013, Red Hat, Inc.
	* Copyright (C) 2010, Blue Swirl <blauwirbel@gmail.com>
	* Copyright (C) 2009, Anthony Liguori <aliguori@us.ibm.com>
	*
	* Author:
	* Laszlo Ersek <lersek@redhat.com>
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to
	* deal in the Software without restriction, including without limitation the
	* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
	* sell copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
	* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
	* IN THE SOFTWARE.
	*/

	#include "qemu/osdep.h"
	#include "block/block_int.h"
	#include "qemu/option.h"

	static QemuOptsList raw_create_opts = {
	.name = "raw-create-opts",
	.head = QTAILQ_HEAD_INITIALIZER(raw_create_opts.head),
	.desc = {
	{
	.name = BLOCK_OPT_SIZE,
	.type = QEMU_OPT_SIZE,
	.help = "Virtual disk size"
	},
	{ /* end of list */ }
	}
	};

	static int raw_reopen_prepare(BDRVReopenState *reopen_state,
	BlockReopenQueue queue, Error *errp)
	{
	return 0;
	}

	static int coroutine_fn raw_co_readv(BlockDriverState *bs, int64_t sector_num,
	int nb_sectors, QEMUIOVector *qiov)
	{
	BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
	return bdrv_co_readv(bs->file->bs, sector_num, nb_sectors, qiov);
	}

	static int coroutine_fn raw_co_writev(BlockDriverState *bs, int64_t sector_num,
	int nb_sectors, QEMUIOVector *qiov)
	{
	void *buf = NULL;
	BlockDriver *drv;
	QEMUIOVector local_qiov;
	int ret;

	if (bs->probed && sector_num == 0) {
	/* As long as these conditions are true, we can't get partial writes to
	* the probe buffer and can just directly check the request. */
	QEMU_BUILD_BUG_ON(BLOCK_PROBE_BUF_SIZE != 512);
	QEMU_BUILD_BUG_ON(BDRV_SECTOR_SIZE != 512);

	if (nb_sectors == 0) {
	/* qemu_iovec_to_buf() would fail, but we want to return success
	* instead of -EINVAL in this case. */
	return 0;
	}

	buf = qemu_try_blockalign(bs->file->bs, 512);
	if (!buf) {
	ret = -ENOMEM;
	goto fail;
	}

	ret = qemu_iovec_to_buf(qiov, 0, buf, 512);
	if (ret != 512) {
	ret = -EINVAL;
	goto fail;
	}

	drv = bdrv_probe_all(buf, 512, NULL);
	if (drv != bs->drv) {
	ret = -EPERM;
	goto fail;
	}

	/* Use the checked buffer, a malicious guest might be overwriting its
	* original buffer in the background. */
	qemu_iovec_init(&local_qiov, qiov->niov + 1);
	qemu_iovec_add(&local_qiov, buf, 512);
	qemu_iovec_concat(&local_qiov, qiov, 512, qiov->size - 512);
	qiov = &local_qiov;
	}

	BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
	ret = bdrv_co_writev(bs->file->bs, sector_num, nb_sectors, qiov);

	fail:
	if (qiov == &local_qiov) {
	qemu_iovec_destroy(&local_qiov);
	}
	qemu_vfree(buf);
	return ret;
	}

	static int64_t coroutine_fn raw_co_get_block_status(BlockDriverState *bs,
	int64_t sector_num,
	int nb_sectors, int *pnum,
	BlockDriverState **file)
	{
	*pnum = nb_sectors;
	*file = bs->file->bs;
	return BDRV_BLOCK_RAW \| BDRV_BLOCK_OFFSET_VALID \| BDRV_BLOCK_DATA \|
	(sector_num << BDRV_SECTOR_BITS);
	}

	static int coroutine_fn raw_co_write_zeroes(BlockDriverState *bs,
	int64_t sector_num, int nb_sectors,
	BdrvRequestFlags flags)
	{
	return bdrv_co_write_zeroes(bs->file->bs, sector_num, nb_sectors, flags);
	}

	static int coroutine_fn raw_co_discard(BlockDriverState *bs,
	int64_t sector_num, int nb_sectors)
	{
	return bdrv_co_discard(bs->file->bs, sector_num, nb_sectors);
	}

	static int64_t raw_getlength(BlockDriverState *bs)
	{
	return bdrv_getlength(bs->file->bs);
	}

	static int raw_get_info(BlockDriverState bs, BlockDriverInfo bdi)
	{
	return bdrv_get_info(bs->file->bs, bdi);
	}

	static void raw_refresh_limits(BlockDriverState bs, Error *errp)
	{
	bs->bl = bs->file->bs->bl;
	}

	static int raw_truncate(BlockDriverState *bs, int64_t offset)
	{
	return bdrv_truncate(bs->file->bs, offset);
	}

	static int raw_media_changed(BlockDriverState *bs)
	{
	return bdrv_media_changed(bs->file->bs);
	}

	static void raw_eject(BlockDriverState *bs, bool eject_flag)
	{
	bdrv_eject(bs->file->bs, eject_flag);
	}

	static void raw_lock_medium(BlockDriverState *bs, bool locked)
	{
	bdrv_lock_medium(bs->file->bs, locked);
	}

	static BlockAIOCB raw_aio_ioctl(BlockDriverState bs,
	unsigned long int req, void *buf,
	BlockCompletionFunc *cb,
	void *opaque)
	{
	return bdrv_aio_ioctl(bs->file->bs, req, buf, cb, opaque);
	}

	static int raw_has_zero_init(BlockDriverState *bs)
	{
	return bdrv_has_zero_init(bs->file->bs);
	}

	static int raw_create(const char filename, QemuOpts opts, Error **errp)
	{
	Error *local_err = NULL;
	int ret;

	ret = bdrv_create_file(filename, opts, &local_err);
	if (local_err) {
	error_propagate(errp, local_err);
	}
	return ret;
	}

	static int raw_open(BlockDriverState bs, QDict options, int flags,
	Error **errp)
	{
	bs->sg = bs->file->bs->sg;

	if (bs->probed && !bdrv_is_read_only(bs)) {
	fprintf(stderr,
	"WARNING: Image format was not specified for '%s' and probing "
	"guessed raw.\n"
	" Automatically detecting the format is dangerous for "
	"raw images, write operations on block 0 will be restricted.\n"
	" Specify the 'raw' format explicitly to remove the "
	"restrictions.\n",
	bs->file->bs->filename);
	}

	return 0;
	}

	static void raw_close(BlockDriverState *bs)
	{
	}

	static int raw_probe(const uint8_t buf, int buf_size, const char filename)
	{
	/* smallest possible positive score so that raw is used if and only if no
	* other block driver works
	*/
	return 1;
	}

	static int raw_probe_blocksizes(BlockDriverState bs, BlockSizes bsz)
	{
	return bdrv_probe_blocksizes(bs->file->bs, bsz);
	}

	static int raw_probe_geometry(BlockDriverState bs, HDGeometry geo)
	{
	return bdrv_probe_geometry(bs->file->bs, geo);
	}

	BlockDriver bdrv_raw = {
	.format_name = "raw",
	.bdrv_probe = &raw_probe,
	.bdrv_reopen_prepare = &raw_reopen_prepare,
	.bdrv_open = &raw_open,
	.bdrv_close = &raw_close,
	.bdrv_create = &raw_create,
	.bdrv_co_readv = &raw_co_readv,
	.bdrv_co_writev = &raw_co_writev,
	.bdrv_co_write_zeroes = &raw_co_write_zeroes,
	.bdrv_co_discard = &raw_co_discard,
	.bdrv_co_get_block_status = &raw_co_get_block_status,
	.bdrv_truncate = &raw_truncate,
	.bdrv_getlength = &raw_getlength,
	.has_variable_length = true,
	.bdrv_get_info = &raw_get_info,
	.bdrv_refresh_limits = &raw_refresh_limits,
	.bdrv_probe_blocksizes = &raw_probe_blocksizes,
	.bdrv_probe_geometry = &raw_probe_geometry,
	.bdrv_media_changed = &raw_media_changed,
	.bdrv_eject = &raw_eject,
	.bdrv_lock_medium = &raw_lock_medium,
	.bdrv_aio_ioctl = &raw_aio_ioctl,
	.create_opts = &raw_create_opts,
	.bdrv_has_zero_init = &raw_has_zero_init
	};

	static void bdrv_raw_init(void)
	{
	bdrv_register(&bdrv_raw);
	}

	block_init(bdrv_raw_init);