зеркало из https://github.com/microsoft/lsvmtools.git
147 строки
3.6 KiB
C
147 строки
3.6 KiB
C
/*
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**==============================================================================
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**
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** LSVMTools
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**
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** MIT License
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**
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** Copyright (c) Microsoft Corporation. All rights reserved.
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**
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** Permission is hereby granted, free of charge, to any person obtaining a copy
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** of this software and associated documentation files (the "Software"), to deal
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** in the Software without restriction, including without limitation the rights
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** to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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** copies of the Software, and to permit persons to whom the Software is
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** furnished to do so, subject to the following conditions:
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**
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** The above copyright notice and this permission notice shall be included in
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** all copies or substantial portions of the Software.
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**
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** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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** IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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** FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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** AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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** LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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** OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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** SOFTWARE
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**
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**==============================================================================
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*/
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#include "blkdev.h"
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#include "strings.h"
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#include "print.h"
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#include "chksum.h"
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int BlkdevRead(
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Blkdev* dev,
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UINTN blkno,
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void* data,
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UINTN size)
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{
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int rc = -1;
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UINTN nblocks;
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UINT8* ptr;
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UINTN rem;
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UINT8 block[BLKDEV_BLKSIZE];
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if (!dev || !data)
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goto done;
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nblocks = (size + BLKDEV_BLKSIZE - 1) / BLKDEV_BLKSIZE;
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ptr = (UINT8*)data;
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rem = size;
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/* Nothing to do. */
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if (nblocks == 0)
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{
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rc = 0;
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goto done;
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}
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/* If size is a multiple of the block size, we just do a batch read. */
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if (size % BLKDEV_BLKSIZE == 0)
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{
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if (dev->GetN(dev, blkno, nblocks, ptr) != 0)
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goto done;
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rc = 0;
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goto done;
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}
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/* Otherwise, we can only read n-1 blocks to avoid overflow. */
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if (dev->GetN(dev, blkno, nblocks - 1, ptr) != 0)
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goto done;
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ptr += (nblocks - 1) * BLKDEV_BLKSIZE;
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rem -= (nblocks - 1) * BLKDEV_BLKSIZE;
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/* Read the last block and copy the remaining bytes to ptr. */
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if (dev->GetN(dev, blkno + nblocks - 1, 1, block) != 0)
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goto done;
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Memcpy(ptr, block, rem);
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rc = 0;
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done:
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return rc;
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}
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int BlkdevWrite(
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Blkdev* dev,
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UINTN blkno,
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const void* data,
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UINTN size)
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{
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int rc = -1;
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UINTN nblocks;
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const UINT8* ptr;
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UINTN rem;
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UINT8 block[BLKDEV_BLKSIZE];
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if (!dev || !data)
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goto done;
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nblocks = (size + BLKDEV_BLKSIZE - 1) / BLKDEV_BLKSIZE;
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ptr = (const UINT8*)data;
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rem = size;
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/* Nothing to do. */
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if (nblocks == 0)
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{
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rc = 0;
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goto done;
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}
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/* If size is aligned to block size, we just do a batch write. */
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if (size % BLKDEV_BLKSIZE == 0)
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{
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if (dev->PutN(dev, blkno, nblocks, ptr) != 0)
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goto done;
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rc = 0;
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goto done;
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}
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/* Otherwise, we can only write nblocks - 1 blocks without overflow. */
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if (dev->PutN(dev, blkno, nblocks - 1, ptr) != 0)
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goto done;
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ptr += (nblocks - 1) * BLKDEV_BLKSIZE;
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rem -= (nblocks - 1) * BLKDEV_BLKSIZE;
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/* Read the last block and rewrite part of it. */
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if (dev->GetN(dev, blkno + nblocks - 1, 1, block) != 0)
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goto done;
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Memcpy(block, ptr, rem);
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if (dev->PutN(dev, blkno + nblocks - 1, 1, block) != 0)
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goto done;
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rc = 0;
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done:
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return rc;
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}
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