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93 lines
2.1 KiB
C
93 lines
2.1 KiB
C
/*-
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* See the file LICENSE for redistribution information.
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*
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* Copyright (c) 2004-2005
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* Sleepycat Software. All rights reserved.
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*
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* $Id: os_truncate.c,v 12.4 2005/10/12 17:57:33 bostic Exp $
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*/
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#include "db_config.h"
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#include "db_int.h"
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/*
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* __os_truncate --
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* Truncate the file.
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*/
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int
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__os_truncate(dbenv, fhp, pgno, pgsize)
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DB_ENV *dbenv;
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DB_FH *fhp;
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db_pgno_t pgno;
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u_int32_t pgsize;
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{
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/* Yes, this really is how Microsoft have designed their API */
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union {
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__int64 bigint;
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struct {
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unsigned long low;
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long high;
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};
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} off;
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off_t offset;
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HANDLE dup_handle;
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int ret;
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ret = 0;
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offset = (off_t)pgsize * pgno;
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if (DB_GLOBAL(j_ftruncate) != NULL) {
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ret = DB_GLOBAL(j_ftruncate)(fhp->fd, offset);
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goto done;
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}
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#ifdef HAVE_FILESYSTEM_NOTZERO
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/*
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* If the filesystem doesn't zero fill, it isn't safe to extend the
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* file, or we end up with junk blocks. Just return in that case.
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*/
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if (__os_fs_notzero()) {
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off_t stat_offset;
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u_int32_t mbytes, bytes;
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/* Stat the file. */
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if ((ret =
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__os_ioinfo(dbenv, NULL, fhp, &mbytes, &bytes, NULL)) != 0)
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return (ret);
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stat_offset = (off_t)mbytes * MEGABYTE + bytes;
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if (offset > stat_offset)
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return (0);
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}
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#endif
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/*
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* Windows doesn't provide truncate directly. Instead, it has
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* SetEndOfFile, which truncates to the current position. To
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* deal with that, we first duplicate the file handle, then
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* seek and set the end of file. This is necessary to avoid
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* races with {Read,Write}File in other threads.
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*/
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if (!DuplicateHandle(GetCurrentProcess(), fhp->handle,
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GetCurrentProcess(), &dup_handle, 0, FALSE,
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DUPLICATE_SAME_ACCESS)) {
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ret = __os_get_errno();
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goto done;
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}
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off.bigint = (__int64)pgsize * pgno;
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RETRY_CHK((SetFilePointer(dup_handle,
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off.low, &off.high, FILE_BEGIN) == INVALID_SET_FILE_POINTER &&
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GetLastError() != NO_ERROR) ||
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!SetEndOfFile(dup_handle), ret);
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if (!CloseHandle(dup_handle) && ret == 0)
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ret = __os_get_errno();
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done: if (ret != 0)
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__db_err(dbenv,
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"ftruncate: %lu: %s", pgno * pgsize, strerror(ret));
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return (ret);
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}
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