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17649d4ac8
Rename dev_read() to dev_read_buf() - the function that reads data into a supplied buffer. Introduce a new dev_read() that allocates the buffer it returns and switch the important users over to this. No caller may change the returned data. (For now, callers are responsible for freeing it after use, but later the device layer will take full ownership.) dev_read_buf() should only be used for tiny buffers or unimportant code (such as the old disk formats).
82 lines
1.7 KiB
C
82 lines
1.7 KiB
C
/*
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* Copyright (C) 2009 Red Hat, Inc. All rights reserved.
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*
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* This file is part of LVM2.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU Lesser General Public License v.2.1.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "lib.h"
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#include "dev-type.h"
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#ifdef __linux__
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#define MAX_PAGESIZE (64 * 1024)
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#define SIGNATURE_SIZE 10
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static int _swap_detect_signature(const char *buf)
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{
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if (memcmp(buf, "SWAP-SPACE", 10) == 0 ||
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memcmp(buf, "SWAPSPACE2", 10) == 0)
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return 1;
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if (memcmp(buf, "S1SUSPEND", 9) == 0 ||
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memcmp(buf, "S2SUSPEND", 9) == 0 ||
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memcmp(buf, "ULSUSPEND", 9) == 0 ||
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memcmp(buf, "\xed\xc3\x02\xe9\x98\x56\xe5\x0c", 8) == 0)
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return 1;
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return 0;
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}
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int dev_is_swap(struct device *dev, uint64_t *offset_found)
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{
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char buf[10];
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uint64_t size;
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unsigned page;
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int ret = 0;
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if (!dev_get_size(dev, &size)) {
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stack;
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return -1;
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}
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if (!dev_open_readonly(dev)) {
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stack;
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return -1;
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}
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for (page = 0x1000; page <= MAX_PAGESIZE; page <<= 1) {
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/*
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* skip 32k pagesize since this does not seem to be supported
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*/
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if (page == 0x8000)
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continue;
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if (size < (page >> SECTOR_SHIFT))
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break;
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if (!dev_read_buf(dev, page - SIGNATURE_SIZE, SIGNATURE_SIZE, DEV_IO_SIGNATURES, buf)) {
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ret = -1;
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break;
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}
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if (_swap_detect_signature(buf)) {
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if (offset_found)
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*offset_found = page - SIGNATURE_SIZE;
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ret = 1;
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break;
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}
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}
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if (!dev_close(dev))
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stack;
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return ret;
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}
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#endif
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