85 lines
2.3 KiB
C
85 lines
2.3 KiB
C
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2015, 2016.
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This file is part of Sortix libmount.
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Sortix libmount is free software: you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by the
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Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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Sortix libmount is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with Sortix libmount. If not, see <http://www.gnu.org/licenses/>.
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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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