1/*-
2 * See the file LICENSE for redistribution information.
3 *
4 * Copyright (c) 2002,2008 Oracle.  All rights reserved.
5 *
6 * $Id: env_file.c,v 12.17 2008/01/08 20:58:22 bostic Exp $
7 */
8
9#include "db_config.h"
10
11#include "db_int.h"
12
13/*
14 * __db_file_extend --
15 *	Initialize a regular file by writing the last page of the file.
16 *
17 * PUBLIC: int __db_file_extend __P((ENV *, DB_FH *, size_t));
18 */
19int
20__db_file_extend(env, fhp, size)
21	ENV *env;
22	DB_FH *fhp;
23	size_t size;
24{
25	db_pgno_t pages;
26	size_t nw;
27	u_int32_t relative;
28	int ret;
29	char *buf;
30
31	/*
32	 * Extend the file by writing the last page.  If the region is >4Gb,
33	 * increment may be larger than the maximum possible seek "relative"
34	 * argument, as it's an unsigned 32-bit value.  Break the offset into
35	 * pages of 1MB each so we don't overflow -- (2^20 + 2^32 is bigger
36	 * than any memory I expect to see for awhile).
37	 */
38#undef	FILE_EXTEND_IO_SIZE
39#define	FILE_EXTEND_IO_SIZE	(8 * 1024)
40	if ((ret = __os_calloc(env, FILE_EXTEND_IO_SIZE, 1, &buf)) != 0)
41		return (ret);
42
43	pages = (db_pgno_t)((size - FILE_EXTEND_IO_SIZE) / MEGABYTE);
44	relative = (u_int32_t)((size - FILE_EXTEND_IO_SIZE) % MEGABYTE);
45	if ((ret = __os_seek(env, fhp, pages, MEGABYTE, relative)) != 0)
46		goto err;
47	if ((ret = __os_write(env, fhp, buf, FILE_EXTEND_IO_SIZE, &nw)) != 0)
48		goto err;
49
50err:	__os_free(env, buf);
51
52	return (0);
53}
54
55/*
56 * __db_file_multi_write  --
57 *	Overwrite a file with multiple passes to corrupt the data.
58 *
59 * PUBLIC: int __db_file_multi_write __P((ENV *, const char *));
60 */
61int
62__db_file_multi_write(env, path)
63	ENV *env;
64	const char *path;
65{
66	DB_FH *fhp;
67	u_int32_t mbytes, bytes;
68	int ret;
69
70	if ((ret = __os_open(env, path, 0, DB_OSO_REGION, 0, &fhp)) == 0 &&
71	    (ret = __os_ioinfo(env, path, fhp, &mbytes, &bytes, NULL)) == 0) {
72		/*
73		 * !!!
74		 * Overwrite a regular file with alternating 0xff, 0x00 and 0xff
75		 * byte patterns.  Implies a fixed-block filesystem, journaling
76		 * or logging filesystems will require operating system support.
77		 */
78		if ((ret =
79		    __db_file_write(env, fhp, mbytes, bytes, 255)) != 0)
80			goto err;
81		if ((ret =
82		    __db_file_write(env, fhp, mbytes, bytes, 0)) != 0)
83			goto err;
84		if ((ret =
85		    __db_file_write(env, fhp, mbytes, bytes, 255)) != 0)
86			goto err;
87	} else
88		__db_err(env, ret, "%s", path);
89
90err:	if (fhp != NULL)
91		(void)__os_closehandle(env, fhp);
92	return (ret);
93}
94
95/*
96 * __db_file_write --
97 *	A single pass over the file, writing the specified byte pattern.
98 *
99 * PUBLIC: int __db_file_write __P((ENV *,
100 * PUBLIC:     DB_FH *, u_int32_t, u_int32_t, int));
101 */
102int
103__db_file_write(env, fhp, mbytes, bytes, pattern)
104	ENV *env;
105	DB_FH *fhp;
106	int pattern;
107	u_int32_t mbytes, bytes;
108{
109	size_t len, nw;
110	int i, ret;
111	char *buf;
112
113#undef	FILE_WRITE_IO_SIZE
114#define	FILE_WRITE_IO_SIZE	(64 * 1024)
115	if ((ret = __os_malloc(env, FILE_WRITE_IO_SIZE, &buf)) != 0)
116		return (ret);
117	memset(buf, pattern, FILE_WRITE_IO_SIZE);
118
119	if ((ret = __os_seek(env, fhp, 0, 0, 0)) != 0)
120		goto err;
121	for (; mbytes > 0; --mbytes)
122		for (i = MEGABYTE / FILE_WRITE_IO_SIZE; i > 0; --i)
123			if ((ret = __os_write(
124			    env, fhp, buf, FILE_WRITE_IO_SIZE, &nw)) != 0)
125				goto err;
126	for (; bytes > 0; bytes -= (u_int32_t)len) {
127		len = bytes < FILE_WRITE_IO_SIZE ? bytes : FILE_WRITE_IO_SIZE;
128		if ((ret = __os_write(env, fhp, buf, len, &nw)) != 0)
129			goto err;
130	}
131
132	ret = __os_fsync(env, fhp);
133
134err:	__os_free(env, buf);
135	return (ret);
136}
137