53 lines
1.8 KiB
C
53 lines
1.8 KiB
C
/*
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* Copyright (c) 2012, 2016 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* crc32.c
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* Calculates a CRC32 Checksum on binary data.
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*/
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// TODO: Remove this file and this feature after releasing Sortix 1.0. Change
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// the checksum algorithm in the initrd header to say none.
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#include <stdbool.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <unistd.h>
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#include <errno.h>
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#include <error.h>
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#include "crc32.h"
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#include "zcrc32.h"
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bool CRC32File(uint32_t* result, const char* name, int fd, off_t offset,
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off_t length)
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{
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uint32_t crc = crc32(0, NULL, 0);
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const size_t BUFFER_SIZE = 16UL * 1024UL;
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uint8_t buffer[BUFFER_SIZE];
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off_t sofar = 0;
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ssize_t amount = 0;
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while ( sofar < length &&
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0 < (amount = pread(fd, buffer, BUFFER_SIZE, offset + sofar)) )
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{
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if ( length - sofar < amount ) { amount = length - sofar; }
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crc = crc32(crc, buffer, amount);
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sofar += amount;
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}
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if ( amount < 0 ) { error(0, errno, "read: %s", name); return false; }
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if ( sofar < length ) { error(0, EIO, "read: %s", name); return false; }
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*result = crc;
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return true;
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}
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