GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libc/db/btree/bt_open.c Lines: 0 163 0.0 %
Date: 2017-11-13 Branches: 0 128 0.0 %

Line Branch Exec Source
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/*	$OpenBSD: bt_open.c,v 1.19 2015/12/28 22:08:18 mmcc Exp $	*/
2
3
/*-
4
 * Copyright (c) 1990, 1993, 1994
5
 *	The Regents of the University of California.  All rights reserved.
6
 *
7
 * This code is derived from software contributed to Berkeley by
8
 * Mike Olson.
9
 *
10
 * Redistribution and use in source and binary forms, with or without
11
 * modification, are permitted provided that the following conditions
12
 * are met:
13
 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. Neither the name of the University nor the names of its contributors
19
 *    may be used to endorse or promote products derived from this software
20
 *    without specific prior written permission.
21
 *
22
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32
 * SUCH DAMAGE.
33
 */
34
35
/*
36
 * Implementation of btree access method for 4.4BSD.
37
 *
38
 * The design here was originally based on that of the btree access method
39
 * used in the Postgres database system at UC Berkeley.  This implementation
40
 * is wholly independent of the Postgres code.
41
 */
42
43
#include <sys/stat.h>
44
45
#include <errno.h>
46
#include <fcntl.h>
47
#include <limits.h>
48
#include <signal.h>
49
#include <stdio.h>
50
#include <stdlib.h>
51
#include <string.h>
52
#include <unistd.h>
53
54
#include <db.h>
55
#include "btree.h"
56
57
#ifdef DEBUG
58
#undef	MINPSIZE
59
#define	MINPSIZE	128
60
#endif
61
62
static int byteorder(void);
63
static int nroot(BTREE *);
64
static int tmp(void);
65
66
/*
67
 * __BT_OPEN -- Open a btree.
68
 *
69
 * Creates and fills a DB struct, and calls the routine that actually
70
 * opens the btree.
71
 *
72
 * Parameters:
73
 *	fname:	filename (NULL for in-memory trees)
74
 *	flags:	open flag bits
75
 *	mode:	open permission bits
76
 *	b:	BTREEINFO pointer
77
 *
78
 * Returns:
79
 *	NULL on failure, pointer to DB on success.
80
 *
81
 */
82
DB *
83
__bt_open(const char *fname, int flags, int mode, const BTREEINFO *openinfo,
84
    int dflags)
85
{
86
	struct stat sb;
87
	BTMETA m;
88
	BTREE *t;
89
	BTREEINFO b;
90
	DB *dbp;
91
	pgno_t ncache;
92
	ssize_t nr;
93
	int machine_lorder, saved_errno;
94
95
	t = NULL;
96
97
	/*
98
	 * Intention is to make sure all of the user's selections are okay
99
	 * here and then use them without checking.  Can't be complete, since
100
	 * we don't know the right page size, lorder or flags until the backing
101
	 * file is opened.  Also, the file's page size can cause the cachesize
102
	 * to change.
103
	 */
104
	machine_lorder = byteorder();
105
	if (openinfo) {
106
		b = *openinfo;
107
108
		/* Flags: R_DUP. */
109
		if (b.flags & ~(R_DUP))
110
			goto einval;
111
112
		/*
113
		 * Page size must be indx_t aligned and >= MINPSIZE.  Default
114
		 * page size is set farther on, based on the underlying file
115
		 * transfer size.
116
		 */
117
		if (b.psize &&
118
		    (b.psize < MINPSIZE || b.psize > MAX_PAGE_OFFSET + 1 ||
119
		    b.psize & (sizeof(indx_t) - 1)))
120
			goto einval;
121
122
		/* Minimum number of keys per page; absolute minimum is 2. */
123
		if (b.minkeypage) {
124
			if (b.minkeypage < 2)
125
				goto einval;
126
		} else
127
			b.minkeypage = DEFMINKEYPAGE;
128
129
		/* If no comparison, use default comparison and prefix. */
130
		if (b.compare == NULL) {
131
			b.compare = __bt_defcmp;
132
			if (b.prefix == NULL)
133
				b.prefix = __bt_defpfx;
134
		}
135
136
		if (b.lorder == 0)
137
			b.lorder = machine_lorder;
138
	} else {
139
		b.compare = __bt_defcmp;
140
		b.cachesize = 0;
141
		b.flags = 0;
142
		b.lorder = machine_lorder;
143
		b.minkeypage = DEFMINKEYPAGE;
144
		b.prefix = __bt_defpfx;
145
		b.psize = 0;
146
	}
147
148
	/* Check for the ubiquitous PDP-11. */
149
	if (b.lorder != BIG_ENDIAN && b.lorder != LITTLE_ENDIAN)
150
		goto einval;
151
152
	/* Allocate and initialize DB and BTREE structures. */
153
	if ((t = calloc(1, sizeof(BTREE))) == NULL)
154
		goto err;
155
	t->bt_fd = -1;			/* Don't close unopened fd on error. */
156
	t->bt_lorder = b.lorder;
157
	t->bt_order = NOT;
158
	t->bt_cmp = b.compare;
159
	t->bt_pfx = b.prefix;
160
	t->bt_rfd = -1;
161
162
	if ((t->bt_dbp = dbp = calloc(1, sizeof(DB))) == NULL)
163
		goto err;
164
	if (t->bt_lorder != machine_lorder)
165
		F_SET(t, B_NEEDSWAP);
166
167
	dbp->type = DB_BTREE;
168
	dbp->internal = t;
169
	dbp->close = __bt_close;
170
	dbp->del = __bt_delete;
171
	dbp->fd = __bt_fd;
172
	dbp->get = __bt_get;
173
	dbp->put = __bt_put;
174
	dbp->seq = __bt_seq;
175
	dbp->sync = __bt_sync;
176
177
	/*
178
	 * If no file name was supplied, this is an in-memory btree and we
179
	 * open a backing temporary file.  Otherwise, it's a disk-based tree.
180
	 */
181
	if (fname) {
182
		switch (flags & O_ACCMODE) {
183
		case O_RDONLY:
184
			F_SET(t, B_RDONLY);
185
			break;
186
		case O_RDWR:
187
			break;
188
		case O_WRONLY:
189
		default:
190
			goto einval;
191
		}
192
193
		if ((t->bt_fd = open(fname, flags | O_CLOEXEC, mode)) < 0)
194
			goto err;
195
196
	} else {
197
		if ((flags & O_ACCMODE) != O_RDWR)
198
			goto einval;
199
		if ((t->bt_fd = tmp()) == -1)
200
			goto err;
201
		F_SET(t, B_INMEM);
202
	}
203
204
	if (fstat(t->bt_fd, &sb))
205
		goto err;
206
	if (sb.st_size) {
207
		if ((nr = read(t->bt_fd, &m, sizeof(BTMETA))) < 0)
208
			goto err;
209
		if (nr != sizeof(BTMETA))
210
			goto eftype;
211
212
		/*
213
		 * Read in the meta-data.  This can change the notion of what
214
		 * the lorder, page size and flags are, and, when the page size
215
		 * changes, the cachesize value can change too.  If the user
216
		 * specified the wrong byte order for an existing database, we
217
		 * don't bother to return an error, we just clear the NEEDSWAP
218
		 * bit.
219
		 */
220
		if (m.magic == BTREEMAGIC)
221
			F_CLR(t, B_NEEDSWAP);
222
		else {
223
			F_SET(t, B_NEEDSWAP);
224
			M_32_SWAP(m.magic);
225
			M_32_SWAP(m.version);
226
			M_32_SWAP(m.psize);
227
			M_32_SWAP(m.free);
228
			M_32_SWAP(m.nrecs);
229
			M_32_SWAP(m.flags);
230
		}
231
		if (m.magic != BTREEMAGIC || m.version != BTREEVERSION)
232
			goto eftype;
233
		if (m.psize < MINPSIZE || m.psize > MAX_PAGE_OFFSET + 1 ||
234
		    m.psize & (sizeof(indx_t) - 1))
235
			goto eftype;
236
		if (m.flags & ~SAVEMETA)
237
			goto eftype;
238
		b.psize = m.psize;
239
		F_SET(t, m.flags);
240
		t->bt_free = m.free;
241
		t->bt_nrecs = m.nrecs;
242
	} else {
243
		/*
244
		 * Set the page size to the best value for I/O to this file.
245
		 * Don't overflow the page offset type.
246
		 */
247
		if (b.psize == 0) {
248
			b.psize = sb.st_blksize;
249
			if (b.psize < MINPSIZE)
250
				b.psize = MINPSIZE;
251
			if (b.psize > MAX_PAGE_OFFSET + 1)
252
				b.psize = MAX_PAGE_OFFSET + 1;
253
		}
254
255
		/* Set flag if duplicates permitted. */
256
		if (!(b.flags & R_DUP))
257
			F_SET(t, B_NODUPS);
258
259
		t->bt_free = P_INVALID;
260
		t->bt_nrecs = 0;
261
		F_SET(t, B_METADIRTY);
262
	}
263
264
	t->bt_psize = b.psize;
265
266
	/* Set the cache size; must be a multiple of the page size. */
267
	if (b.cachesize && b.cachesize & (b.psize - 1))
268
		b.cachesize += (~b.cachesize & (b.psize - 1)) + 1;
269
	if (b.cachesize < b.psize * MINCACHE)
270
		b.cachesize = b.psize * MINCACHE;
271
272
	/* Calculate number of pages to cache. */
273
	ncache = (b.cachesize + t->bt_psize - 1) / t->bt_psize;
274
275
	/*
276
	 * The btree data structure requires that at least two keys can fit on
277
	 * a page, but other than that there's no fixed requirement.  The user
278
	 * specified a minimum number per page, and we translated that into the
279
	 * number of bytes a key/data pair can use before being placed on an
280
	 * overflow page.  This calculation includes the page header, the size
281
	 * of the index referencing the leaf item and the size of the leaf item
282
	 * structure.  Also, don't let the user specify a minkeypage such that
283
	 * a key/data pair won't fit even if both key and data are on overflow
284
	 * pages.
285
	 */
286
	t->bt_ovflsize = (t->bt_psize - BTDATAOFF) / b.minkeypage -
287
	    (sizeof(indx_t) + NBLEAFDBT(0, 0));
288
	if (t->bt_ovflsize < NBLEAFDBT(NOVFLSIZE, NOVFLSIZE) + sizeof(indx_t))
289
		t->bt_ovflsize =
290
		    NBLEAFDBT(NOVFLSIZE, NOVFLSIZE) + sizeof(indx_t);
291
292
	/* Initialize the buffer pool. */
293
	if ((t->bt_mp =
294
	    mpool_open(NULL, t->bt_fd, t->bt_psize, ncache)) == NULL)
295
		goto err;
296
	if (!F_ISSET(t, B_INMEM))
297
		mpool_filter(t->bt_mp, __bt_pgin, __bt_pgout, t);
298
299
	/* Create a root page if new tree. */
300
	if (nroot(t) == RET_ERROR)
301
		goto err;
302
303
	/* Global flags. */
304
	if (dflags & DB_LOCK)
305
		F_SET(t, B_DB_LOCK);
306
	if (dflags & DB_SHMEM)
307
		F_SET(t, B_DB_SHMEM);
308
	if (dflags & DB_TXN)
309
		F_SET(t, B_DB_TXN);
310
311
	return (dbp);
312
313
einval:	errno = EINVAL;
314
	goto err;
315
316
eftype:	errno = EFTYPE;
317
	goto err;
318
319
err:	saved_errno = errno;
320
	if (t) {
321
		free(t->bt_dbp);
322
		if (t->bt_fd != -1)
323
			(void)close(t->bt_fd);
324
		free(t);
325
	}
326
	errno = saved_errno;
327
	return (NULL);
328
}
329
330
/*
331
 * NROOT -- Create the root of a new tree.
332
 *
333
 * Parameters:
334
 *	t:	tree
335
 *
336
 * Returns:
337
 *	RET_ERROR, RET_SUCCESS
338
 */
339
static int
340
nroot(BTREE *t)
341
{
342
	PAGE *meta, *root;
343
	pgno_t npg;
344
345
	if ((root = mpool_get(t->bt_mp, 1, 0)) != NULL) {
346
		if (root->lower == 0 &&
347
		    root->pgno == 0 &&
348
		    root->linp[0] == 0) {
349
			mpool_delete(t->bt_mp, root);
350
			errno = EINVAL;
351
		} else {
352
			mpool_put(t->bt_mp, root, 0);
353
			return (RET_SUCCESS);
354
		}
355
	}
356
	if (errno != EINVAL)		/* It's OK to not exist. */
357
		return (RET_ERROR);
358
	errno = 0;
359
360
	if ((meta = mpool_new(t->bt_mp, &npg, MPOOL_PAGE_NEXT)) == NULL)
361
		return (RET_ERROR);
362
363
	if ((root = mpool_new(t->bt_mp, &npg, MPOOL_PAGE_NEXT)) == NULL)
364
		return (RET_ERROR);
365
366
	if (npg != P_ROOT)
367
		return (RET_ERROR);
368
	root->pgno = npg;
369
	root->prevpg = root->nextpg = P_INVALID;
370
	root->lower = BTDATAOFF;
371
	root->upper = t->bt_psize;
372
	root->flags = P_BLEAF;
373
	memset(meta, 0, t->bt_psize);
374
	mpool_put(t->bt_mp, meta, MPOOL_DIRTY);
375
	mpool_put(t->bt_mp, root, MPOOL_DIRTY);
376
	return (RET_SUCCESS);
377
}
378
379
static int
380
tmp(void)
381
{
382
	sigset_t set, oset;
383
	int fd, len;
384
	char *envtmp = NULL;
385
	char path[PATH_MAX];
386
387
	if (issetugid() == 0)
388
		envtmp = getenv("TMPDIR");
389
	len = snprintf(path,
390
	    sizeof(path), "%s/bt.XXXXXX", envtmp ? envtmp : "/tmp");
391
	if (len < 0 || len >= sizeof(path)) {
392
		errno = ENAMETOOLONG;
393
		return(-1);
394
	}
395
396
	(void)sigfillset(&set);
397
	(void)sigprocmask(SIG_BLOCK, &set, &oset);
398
	if ((fd = mkostemp(path, O_CLOEXEC)) != -1)
399
		(void)unlink(path);
400
	(void)sigprocmask(SIG_SETMASK, &oset, NULL);
401
	return(fd);
402
}
403
404
static int
405
byteorder(void)
406
{
407
	u_int32_t x;
408
	u_char *p;
409
410
	x = 0x01020304;
411
	p = (u_char *)&x;
412
	switch (*p) {
413
	case 1:
414
		return (BIG_ENDIAN);
415
	case 4:
416
		return (LITTLE_ENDIAN);
417
	default:
418
		return (0);
419
	}
420
}
421
422
int
423
__bt_fd(const DB *dbp)
424
{
425
	BTREE *t;
426
427
	t = dbp->internal;
428
429
	/* Toss any page pinned across calls. */
430
	if (t->bt_pinned != NULL) {
431
		mpool_put(t->bt_mp, t->bt_pinned, 0);
432
		t->bt_pinned = NULL;
433
	}
434
435
	/* In-memory database can't have a file descriptor. */
436
	if (F_ISSET(t, B_INMEM)) {
437
		errno = ENOENT;
438
		return (-1);
439
	}
440
	return (t->bt_fd);
441
}