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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 2002, 2015 Oracle and/or its affiliates. All rights reserved.
*
* $Id$
*/
#include "db_config.h"
#include "db_int.h"
/*
* __db_file_extend --
* Initialize or extend a regular file by writing to its last page.
*
* PUBLIC: int __db_file_extend __P((ENV *, DB_FH *, size_t));
*/
int
__db_file_extend(env, fhp, size)
ENV *env;
DB_FH *fhp;
size_t size;
{
db_pgno_t pages;
size_t nw;
u_int32_t relative;
int ret;
char buf;
#ifdef HAVE_MMAP_EXTEND
unsigned pagesize;
/*
* Round up size to the VM pagesize. If it isn't aligned, then the bytes
* ending the mapping might have no corresponding backing location on
* disk, and could be silently lost when the process exits. [#23290]
*/
if (F_ISSET(fhp, DB_FH_REGION)) {
pagesize = (unsigned)getpagesize();
size = DB_ALIGN(size, pagesize);
}
#endif
buf = '\0';
/*
* Extend the file by writing the last page. If the region is >4Gb,
* increment may be larger than the maximum possible seek "relative"
* argument, as it's an unsigned 32-bit value. Break the offset into
* pages of 1MB each so we don't overflow -- (2^20 * 2^32 is bigger
* than any memory I expect to see for awhile).
*/
pages = (db_pgno_t)((size - sizeof(buf)) / MEGABYTE);
relative = (u_int32_t)((size - sizeof(buf)) % MEGABYTE);
if ((ret = __os_seek(env, fhp, pages, MEGABYTE, relative)) == 0)
ret = __os_write(env, fhp, &buf, sizeof(buf), &nw);
return (ret);
}
/*
* __db_file_multi_write --
* Overwrite a file with multiple passes to corrupt the data.
*
* PUBLIC: int __db_file_multi_write __P((ENV *, const char *));
*/
int
__db_file_multi_write(env, path)
ENV *env;
const char *path;
{
DB_FH *fhp;
u_int32_t mbytes, bytes;
int ret;
if ((ret = __os_open(env, path, 0, DB_OSO_REGION, 0, &fhp)) == 0 &&
(ret = __os_ioinfo(env, path, fhp, &mbytes, &bytes, NULL)) == 0) {
/*
* !!!
* Overwrite a regular file with alternating 0xff, 0x00 and 0xff
* byte patterns. Implies a fixed-block filesystem, journaling
* or logging filesystems will require operating system support.
*/
if ((ret =
__db_file_write(env, fhp, mbytes, bytes, 255)) != 0)
goto err;
if ((ret =
__db_file_write(env, fhp, mbytes, bytes, 0)) != 0)
goto err;
if ((ret =
__db_file_write(env, fhp, mbytes, bytes, 255)) != 0)
goto err;
} else
__db_err(env, ret, "%s", path);
err: if (fhp != NULL)
(void)__os_closehandle(env, fhp);
return (ret);
}
/*
* __db_file_write --
* A single pass over the file, writing the specified byte pattern.
*
* PUBLIC: int __db_file_write __P((ENV *,
* PUBLIC: DB_FH *, u_int32_t, u_int32_t, int));
*/
int
__db_file_write(env, fhp, mbytes, bytes, pattern)
ENV *env;
DB_FH *fhp;
int pattern;
u_int32_t mbytes, bytes;
{
size_t len, nw;
int i, ret;
char *buf;
#undef FILE_WRITE_IO_SIZE
#define FILE_WRITE_IO_SIZE (64 * 1024)
if ((ret = __os_malloc(env, FILE_WRITE_IO_SIZE, &buf)) != 0)
return (ret);
memset(buf, pattern, FILE_WRITE_IO_SIZE);
if ((ret = __os_seek(env, fhp, 0, 0, 0)) != 0)
goto err;
for (; mbytes > 0; --mbytes)
for (i = MEGABYTE / FILE_WRITE_IO_SIZE; i > 0; --i)
if ((ret = __os_write(
env, fhp, buf, FILE_WRITE_IO_SIZE, &nw)) != 0)
goto err;
for (; bytes > 0; bytes -= (u_int32_t)len) {
len = bytes < FILE_WRITE_IO_SIZE ? bytes : FILE_WRITE_IO_SIZE;
if ((ret = __os_write(env, fhp, buf, len, &nw)) != 0)
goto err;
}
ret = __os_fsync(env, fhp);
err: __os_free(env, buf);
return (ret);
}
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