80 lines
2.2 KiB
C
80 lines
2.2 KiB
C
/*
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* Copyright (c) 2015, 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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* blockdevice.c
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* Block device abstraction.
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*/
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <assert.h>
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#include <errno.h>
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#include <ioleast.h>
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#include <stdbool.h>
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#include <stdint.h>
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#include <mount/blockdevice.h>
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#include <mount/harddisk.h>
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#include <mount/partition.h>
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blksize_t blockdevice_logical_block_size(const struct blockdevice* bdev)
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{
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while ( bdev->p )
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bdev = bdev->p->parent_bdev;
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assert(bdev->hd);
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return bdev->hd->logical_block_size;
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}
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bool blockdevice_check_reasonable_block_size(blksize_t size)
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{
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if ( size < 512 ) // Violates assumptions.
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return false;
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for ( blksize_t cmp = 512; cmp <= 65536; cmp *= 2 )
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if ( cmp == size )
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return true;
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return false;
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}
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off_t blockdevice_size(const struct blockdevice* bdev)
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{
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if ( bdev->p )
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return bdev->p->length;
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assert(bdev->hd);
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return bdev->hd->st.st_size;
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}
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size_t blockdevice_preadall(const struct blockdevice* bdev,
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void* buffer,
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size_t count,
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off_t off)
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{
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if ( off < 0 )
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return errno = EINVAL, 0;
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while ( bdev->p )
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{
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if ( bdev->p->length < off )
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return 0;
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off_t available = bdev->p->length - off;
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if ( (uintmax_t) available < (uintmax_t) count )
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count = (size_t) available;
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if ( __builtin_add_overflow(bdev->p->start, off, &off) )
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return 0;
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bdev = bdev->p->parent_bdev;
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}
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assert(bdev->hd);
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return preadall(bdev->hd->fd, buffer, count, off);
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}
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