142 lines
4.5 KiB
C
142 lines
4.5 KiB
C
/*
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* Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com)
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* - The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#define _LARGEFILE64_SOURCE
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#define _FILE_OFFSET_BITS 64
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#include <ext4_config.h>
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#include <ext4_blockdev.h>
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#include <ext4_errno.h>
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#include <stdio.h>
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#include <stdbool.h>
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#include <string.h>
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/**@brief Default filename.*/
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static const char *fname = "ext2";
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/**@brief Image block size.*/
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#define EXT4_FILEDEV_BSIZE 512
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/**@brief Image file descriptor.*/
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static FILE *dev_file;
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#define DROP_LINUXCACHE_BUFFERS 0
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/**********************BLOCKDEV INTERFACE**************************************/
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static int file_dev_open(struct ext4_blockdev *bdev);
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static int file_dev_bread(struct ext4_blockdev *bdev, void *buf, uint64_t blk_id,
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uint32_t blk_cnt);
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static int file_dev_bwrite(struct ext4_blockdev *bdev, const void *buf,
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uint64_t blk_id, uint32_t blk_cnt);
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static int file_dev_close(struct ext4_blockdev *bdev);
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/******************************************************************************/
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EXT4_BLOCKDEV_STATIC_INSTANCE(file_dev, EXT4_FILEDEV_BSIZE, 0, file_dev_open,
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file_dev_bread, file_dev_bwrite, file_dev_close, 0, 0);
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/******************************************************************************/
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static int file_dev_open(struct ext4_blockdev *bdev)
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{
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dev_file = fopen(fname, "r+b");
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if (!dev_file)
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return EIO;
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/*No buffering at file.*/
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setbuf(dev_file, 0);
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if (fseeko(dev_file, 0, SEEK_END))
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return EFAULT;
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file_dev.part_offset = 0;
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file_dev.part_size = ftello(dev_file);
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file_dev.bdif->ph_bcnt = file_dev.part_size / file_dev.bdif->ph_bsize;
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return EOK;
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}
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/******************************************************************************/
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static int file_dev_bread(struct ext4_blockdev *bdev, void *buf, uint64_t blk_id,
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uint32_t blk_cnt)
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{
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if (fseeko(dev_file, blk_id * bdev->bdif->ph_bsize, SEEK_SET))
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return EIO;
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if (!blk_cnt)
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return EOK;
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if (!fread(buf, bdev->bdif->ph_bsize * blk_cnt, 1, dev_file))
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return EIO;
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return EOK;
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}
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static void drop_cache(void)
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{
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#if defined(__linux__) && DROP_LINUXCACHE_BUFFERS
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int fd;
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char *data = "3";
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sync();
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fd = open("/proc/sys/vm/drop_caches", O_WRONLY);
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write(fd, data, sizeof(char));
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close(fd);
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#endif
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}
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/******************************************************************************/
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static int file_dev_bwrite(struct ext4_blockdev *bdev, const void *buf,
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uint64_t blk_id, uint32_t blk_cnt)
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{
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if (fseeko(dev_file, blk_id * bdev->bdif->ph_bsize, SEEK_SET))
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return EIO;
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if (!blk_cnt)
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return EOK;
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if (!fwrite(buf, bdev->bdif->ph_bsize * blk_cnt, 1, dev_file))
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return EIO;
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drop_cache();
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return EOK;
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}
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/******************************************************************************/
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static int file_dev_close(struct ext4_blockdev *bdev)
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{
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fclose(dev_file);
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return EOK;
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}
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/******************************************************************************/
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struct ext4_blockdev *file_dev_get(void)
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{
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return &file_dev;
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}
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/******************************************************************************/
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void file_dev_name_set(const char *n)
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{
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fname = n;
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}
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/******************************************************************************/
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