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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 2004, 2012 Oracle and/or its affiliates. All rights reserved.
*
* $Id$
*/
#include "db_config.h"
#include "db_int.h"
/*
* __os_truncate --
* Truncate the file.
*/
int
__os_truncate(env, fhp, pgno, pgsize)
ENV *env;
DB_FH *fhp;
db_pgno_t pgno;
u_int32_t pgsize;
{
/* Yes, this really is how Microsoft have designed their API */
union {
__int64 bigint;
struct {
unsigned long low;
long high;
};
} off;
DB_ENV *dbenv;
off_t offset;
int ret;
dbenv = env == NULL ? NULL : env->dbenv;
offset = (off_t)pgsize * pgno;
ret = 0;
if (dbenv != NULL &&
FLD_ISSET(dbenv->verbose, DB_VERB_FILEOPS | DB_VERB_FILEOPS_ALL))
__db_msg(env, DB_STR_A("0021", "fileops: truncate %s to %lu",
"%s %lu"), fhp->name, (u_long)offset);
#ifdef HAVE_FILESYSTEM_NOTZERO
/*
* If the filesystem doesn't zero fill, it isn't safe to extend the
* file, or we end up with junk blocks. Just return in that case.
*/
if (__os_fs_notzero()) {
off_t stat_offset;
u_int32_t mbytes, bytes;
/* Stat the file. */
if ((ret =
__os_ioinfo(env, NULL, fhp, &mbytes, &bytes, NULL)) != 0)
return (ret);
stat_offset = (off_t)mbytes * MEGABYTE + bytes;
if (offset > stat_offset)
return (0);
}
#endif
LAST_PANIC_CHECK_BEFORE_IO(env);
/*
* Windows doesn't provide truncate directly. Instead, it has
* SetEndOfFile, which truncates to the current position. To
* deal with that, we open a duplicate file handle for truncating.
*
* We want to retry the truncate call, which involves a SetFilePointer
* and a SetEndOfFile, but there are several complications:
*
* 1) since the Windows API deals in 32-bit values, it's possible that
* the return from SetFilePointer (the low 32-bits) is
* INVALID_SET_FILE_POINTER even when the call has succeeded. So we
* have to also check whether GetLastError() returns NO_ERROR.
*
* 2) when it returns, SetFilePointer overwrites the high bits of the
* offset, so if we need to retry, we have to reset the offset each
* time.
*
* We can't switch to SetFilePointerEx, which knows about 64-bit
* offsets, because it isn't supported on Win9x/ME.
*/
RETRY_CHK((off.bigint = (__int64)pgsize * pgno,
(SetFilePointer(fhp->trunc_handle, off.low, &off.high, FILE_BEGIN)
== INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR) ||
!SetEndOfFile(fhp->trunc_handle)), ret);
if (ret != 0) {
__db_syserr(env, ret, DB_STR_A("0022", "SetFilePointer: %lu",
"%lu"), pgno * pgsize);
ret = __os_posix_err(ret);
}
return (ret);
}
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