GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libc/db/hash/hash_page.c Lines: 13 383 3.4 %
Date: 2017-11-07 Branches: 10 226 4.4 %

Line Branch Exec Source
1
/*	$OpenBSD: hash_page.c,v 1.23 2016/12/18 17:07:58 krw 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
 * Margo Seltzer.
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
14
 *    notice, this list of conditions and the following disclaimer.
15
 * 2. Redistributions in binary form must reproduce the above copyright
16
 *    notice, this list of conditions and the following disclaimer in the
17
 *    documentation and/or other materials provided with the distribution.
18
 * 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
23
 * 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
26
 * 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
 * PACKAGE:  hashing
37
 *
38
 * DESCRIPTION:
39
 *	Page manipulation for hashing package.
40
 *
41
 * ROUTINES:
42
 *
43
 * External
44
 *	__get_page
45
 *	__add_ovflpage
46
 * Internal
47
 *	overflow_page
48
 *	open_temp
49
 */
50
51
#include <errno.h>
52
#include <fcntl.h>
53
#include <limits.h>
54
#include <signal.h>
55
#include <stdio.h>
56
#include <stdlib.h>
57
#include <string.h>
58
#include <unistd.h>
59
#ifdef DEBUG
60
#include <assert.h>
61
#endif
62
63
#include <db.h>
64
#include "hash.h"
65
#include "page.h"
66
#include "extern.h"
67
68
static u_int32_t *fetch_bitmap(HTAB *, int);
69
static u_int32_t  first_free(u_int32_t);
70
static int	  open_temp(HTAB *);
71
static u_int16_t  overflow_page(HTAB *);
72
static void	  putpair(char *, const DBT *, const DBT *);
73
static void	  squeeze_key(u_int16_t *, const DBT *, const DBT *);
74
static int	  ugly_split(HTAB *, u_int32_t, BUFHEAD *, BUFHEAD *, int, int);
75
76
#define	PAGE_INIT(P) { \
77
	((u_int16_t *)(P))[0] = 0; \
78
	((u_int16_t *)(P))[1] = hashp->BSIZE - 3 * sizeof(u_int16_t); \
79
	((u_int16_t *)(P))[2] = hashp->BSIZE; \
80
}
81
82
/*
83
 * This is called AFTER we have verified that there is room on the page for
84
 * the pair (PAIRFITS has returned true) so we go right ahead and start moving
85
 * stuff on.
86
 */
87
static void
88
putpair(char *p, const DBT *key, const DBT *val)
89
{
90
	u_int16_t *bp, n, off;
91
92
	bp = (u_int16_t *)p;
93
94
	/* Enter the key first. */
95
	n = bp[0];
96
97
	off = OFFSET(bp) - key->size;
98
	memmove(p + off, key->data, key->size);
99
	bp[++n] = off;
100
101
	/* Now the data. */
102
	off -= val->size;
103
	memmove(p + off, val->data, val->size);
104
	bp[++n] = off;
105
106
	/* Adjust page info. */
107
	bp[0] = n;
108
	bp[n + 1] = off - ((n + 3) * sizeof(u_int16_t));
109
	bp[n + 2] = off;
110
}
111
112
/*
113
 * Returns:
114
 *	 0 OK
115
 *	-1 error
116
 */
117
int
118
__delpair(HTAB *hashp, BUFHEAD *bufp, int ndx)
119
{
120
	u_int16_t *bp, newoff, pairlen;
121
	int n;
122
123
	bp = (u_int16_t *)bufp->page;
124
	n = bp[0];
125
126
	if (bp[ndx + 1] < REAL_KEY)
127
		return (__big_delete(hashp, bufp));
128
	if (ndx != 1)
129
		newoff = bp[ndx - 1];
130
	else
131
		newoff = hashp->BSIZE;
132
	pairlen = newoff - bp[ndx + 1];
133
134
	if (ndx != (n - 1)) {
135
		/* Hard Case -- need to shuffle keys */
136
		int i;
137
		char *src = bufp->page + (int)OFFSET(bp);
138
		char *dst = src + (int)pairlen;
139
		memmove(dst, src, bp[ndx + 1] - OFFSET(bp));
140
141
		/* Now adjust the pointers */
142
		for (i = ndx + 2; i <= n; i += 2) {
143
			if (bp[i + 1] == OVFLPAGE) {
144
				bp[i - 2] = bp[i];
145
				bp[i - 1] = bp[i + 1];
146
			} else {
147
				bp[i - 2] = bp[i] + pairlen;
148
				bp[i - 1] = bp[i + 1] + pairlen;
149
			}
150
		}
151
		if (ndx == hashp->cndx) {
152
			/*
153
			 * We just removed pair we were "pointing" to.
154
			 * By moving back the cndx we ensure subsequent
155
			 * hash_seq() calls won't skip over any entries.
156
			 */
157
			hashp->cndx -= 2;
158
		}
159
	}
160
	/* Finally adjust the page data */
161
	bp[n] = OFFSET(bp) + pairlen;
162
	bp[n - 1] = bp[n + 1] + pairlen + 2 * sizeof(u_int16_t);
163
	bp[0] = n - 2;
164
	hashp->NKEYS--;
165
166
	bufp->flags |= BUF_MOD;
167
	return (0);
168
}
169
/*
170
 * Returns:
171
 *	 0 ==> OK
172
 *	-1 ==> Error
173
 */
174
int
175
__split_page(HTAB *hashp, u_int32_t obucket, u_int32_t nbucket)
176
{
177
	BUFHEAD *new_bufp, *old_bufp;
178
	u_int16_t *ino;
179
	char *np;
180
	DBT key, val;
181
	int n, ndx, retval;
182
	u_int16_t copyto, diff, off, moved;
183
	char *op;
184
185
	copyto = (u_int16_t)hashp->BSIZE;
186
	off = (u_int16_t)hashp->BSIZE;
187
	old_bufp = __get_buf(hashp, obucket, NULL, 0);
188
	if (old_bufp == NULL)
189
		return (-1);
190
	new_bufp = __get_buf(hashp, nbucket, NULL, 0);
191
	if (new_bufp == NULL)
192
		return (-1);
193
194
	old_bufp->flags |= (BUF_MOD | BUF_PIN);
195
	new_bufp->flags |= (BUF_MOD | BUF_PIN);
196
197
	ino = (u_int16_t *)(op = old_bufp->page);
198
	np = new_bufp->page;
199
200
	moved = 0;
201
202
	for (n = 1, ndx = 1; n < ino[0]; n += 2) {
203
		if (ino[n + 1] < REAL_KEY) {
204
			retval = ugly_split(hashp, obucket, old_bufp, new_bufp,
205
			    (int)copyto, (int)moved);
206
			old_bufp->flags &= ~BUF_PIN;
207
			new_bufp->flags &= ~BUF_PIN;
208
			return (retval);
209
210
		}
211
		key.data = (u_char *)op + ino[n];
212
		key.size = off - ino[n];
213
214
		if (__call_hash(hashp, key.data, key.size) == obucket) {
215
			/* Don't switch page */
216
			diff = copyto - off;
217
			if (diff) {
218
				copyto = ino[n + 1] + diff;
219
				memmove(op + copyto, op + ino[n + 1],
220
				    off - ino[n + 1]);
221
				ino[ndx] = copyto + ino[n] - ino[n + 1];
222
				ino[ndx + 1] = copyto;
223
			} else
224
				copyto = ino[n + 1];
225
			ndx += 2;
226
		} else {
227
			/* Switch page */
228
			val.data = (u_char *)op + ino[n + 1];
229
			val.size = ino[n] - ino[n + 1];
230
			putpair(np, &key, &val);
231
			moved += 2;
232
		}
233
234
		off = ino[n + 1];
235
	}
236
237
	/* Now clean up the page */
238
	ino[0] -= moved;
239
	FREESPACE(ino) = copyto - sizeof(u_int16_t) * (ino[0] + 3);
240
	OFFSET(ino) = copyto;
241
242
#ifdef DEBUG3
243
	(void)fprintf(stderr, "split %d/%d\n",
244
	    ((u_int16_t *)np)[0] / 2,
245
	    ((u_int16_t *)op)[0] / 2);
246
#endif
247
	/* unpin both pages */
248
	old_bufp->flags &= ~BUF_PIN;
249
	new_bufp->flags &= ~BUF_PIN;
250
	return (0);
251
}
252
253
/*
254
 * Called when we encounter an overflow or big key/data page during split
255
 * handling.  This is special cased since we have to begin checking whether
256
 * the key/data pairs fit on their respective pages and because we may need
257
 * overflow pages for both the old and new pages.
258
 *
259
 * The first page might be a page with regular key/data pairs in which case
260
 * we have a regular overflow condition and just need to go on to the next
261
 * page or it might be a big key/data pair in which case we need to fix the
262
 * big key/data pair.
263
 *
264
 * Returns:
265
 *	 0 ==> success
266
 *	-1 ==> failure
267
 */
268
static int
269
ugly_split(HTAB *hashp,
270
    u_int32_t obucket,	/* Same as __split_page. */
271
    BUFHEAD *old_bufp,
272
    BUFHEAD *new_bufp,
273
    int copyto,		/* First byte on page which contains key/data values. */
274
    int moved)		/* Number of pairs moved to new page. */
275
{
276
	BUFHEAD *bufp;	/* Buffer header for ino */
277
	u_int16_t *ino;	/* Page keys come off of */
278
	u_int16_t *np;	/* New page */
279
	u_int16_t *op;	/* Page keys go on to if they aren't moving */
280
281
	BUFHEAD *last_bfp;	/* Last buf header OVFL needing to be freed */
282
	DBT key, val;
283
	SPLIT_RETURN ret;
284
	u_int16_t n, off, ov_addr, scopyto;
285
	char *cino;		/* Character value of ino */
286
287
	bufp = old_bufp;
288
	ino = (u_int16_t *)old_bufp->page;
289
	np = (u_int16_t *)new_bufp->page;
290
	op = (u_int16_t *)old_bufp->page;
291
	last_bfp = NULL;
292
	scopyto = (u_int16_t)copyto;	/* ANSI */
293
294
	n = ino[0] - 1;
295
	while (n < ino[0]) {
296
		if (ino[2] < REAL_KEY && ino[2] != OVFLPAGE) {
297
			if (__big_split(hashp, old_bufp,
298
			    new_bufp, bufp, bufp->addr, obucket, &ret))
299
				return (-1);
300
			old_bufp = ret.oldp;
301
			if (!old_bufp)
302
				return (-1);
303
			op = (u_int16_t *)old_bufp->page;
304
			new_bufp = ret.newp;
305
			if (!new_bufp)
306
				return (-1);
307
			np = (u_int16_t *)new_bufp->page;
308
			bufp = ret.nextp;
309
			if (!bufp)
310
				return (0);
311
			cino = (char *)bufp->page;
312
			ino = (u_int16_t *)cino;
313
			last_bfp = ret.nextp;
314
		} else if (ino[n + 1] == OVFLPAGE) {
315
			ov_addr = ino[n];
316
			/*
317
			 * Fix up the old page -- the extra 2 are the fields
318
			 * which contained the overflow information.
319
			 */
320
			ino[0] -= (moved + 2);
321
			FREESPACE(ino) =
322
			    scopyto - sizeof(u_int16_t) * (ino[0] + 3);
323
			OFFSET(ino) = scopyto;
324
325
			bufp = __get_buf(hashp, ov_addr, bufp, 0);
326
			if (!bufp)
327
				return (-1);
328
329
			ino = (u_int16_t *)bufp->page;
330
			n = 1;
331
			scopyto = hashp->BSIZE;
332
			moved = 0;
333
334
			if (last_bfp)
335
				__free_ovflpage(hashp, last_bfp);
336
			last_bfp = bufp;
337
		}
338
		/* Move regular sized pairs of there are any */
339
		off = hashp->BSIZE;
340
		for (n = 1; (n < ino[0]) && (ino[n + 1] >= REAL_KEY); n += 2) {
341
			cino = (char *)ino;
342
			key.data = (u_char *)cino + ino[n];
343
			key.size = off - ino[n];
344
			val.data = (u_char *)cino + ino[n + 1];
345
			val.size = ino[n] - ino[n + 1];
346
			off = ino[n + 1];
347
348
			if (__call_hash(hashp, key.data, key.size) == obucket) {
349
				/* Keep on old page */
350
				if (PAIRFITS(op, (&key), (&val)))
351
					putpair((char *)op, &key, &val);
352
				else {
353
					old_bufp =
354
					    __add_ovflpage(hashp, old_bufp);
355
					if (!old_bufp)
356
						return (-1);
357
					op = (u_int16_t *)old_bufp->page;
358
					putpair((char *)op, &key, &val);
359
				}
360
				old_bufp->flags |= BUF_MOD;
361
			} else {
362
				/* Move to new page */
363
				if (PAIRFITS(np, (&key), (&val)))
364
					putpair((char *)np, &key, &val);
365
				else {
366
					new_bufp =
367
					    __add_ovflpage(hashp, new_bufp);
368
					if (!new_bufp)
369
						return (-1);
370
					np = (u_int16_t *)new_bufp->page;
371
					putpair((char *)np, &key, &val);
372
				}
373
				new_bufp->flags |= BUF_MOD;
374
			}
375
		}
376
	}
377
	if (last_bfp)
378
		__free_ovflpage(hashp, last_bfp);
379
	return (0);
380
}
381
382
/*
383
 * Add the given pair to the page
384
 *
385
 * Returns:
386
 *	0 ==> OK
387
 *	1 ==> failure
388
 */
389
int
390
__addel(HTAB *hashp, BUFHEAD *bufp, const DBT *key, const DBT *val)
391
{
392
	u_int16_t *bp, *sop;
393
	int do_expand;
394
395
	bp = (u_int16_t *)bufp->page;
396
	do_expand = 0;
397
	while (bp[0] && (bp[2] < REAL_KEY || bp[bp[0]] < REAL_KEY))
398
		/* Exception case */
399
		if (bp[2] == FULL_KEY_DATA && bp[0] == 2)
400
			/* This is the last page of a big key/data pair
401
			   and we need to add another page */
402
			break;
403
		else if (bp[2] < REAL_KEY && bp[bp[0]] != OVFLPAGE) {
404
			bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
405
			if (!bufp)
406
				return (-1);
407
			bp = (u_int16_t *)bufp->page;
408
		} else if (bp[bp[0]] != OVFLPAGE) {
409
			/* Short key/data pairs, no more pages */
410
			break;
411
		} else {
412
			/* Try to squeeze key on this page */
413
			if (bp[2] >= REAL_KEY &&
414
			    FREESPACE(bp) >= PAIRSIZE(key, val)) {
415
				squeeze_key(bp, key, val);
416
				goto stats;
417
			} else {
418
				bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0);
419
				if (!bufp)
420
					return (-1);
421
				bp = (u_int16_t *)bufp->page;
422
			}
423
		}
424
425
	if (PAIRFITS(bp, key, val))
426
		putpair(bufp->page, key, val);
427
	else {
428
		do_expand = 1;
429
		bufp = __add_ovflpage(hashp, bufp);
430
		if (!bufp)
431
			return (-1);
432
		sop = (u_int16_t *)bufp->page;
433
434
		if (PAIRFITS(sop, key, val))
435
			putpair((char *)sop, key, val);
436
		else
437
			if (__big_insert(hashp, bufp, key, val))
438
				return (-1);
439
	}
440
stats:
441
	bufp->flags |= BUF_MOD;
442
	/*
443
	 * If the average number of keys per bucket exceeds the fill factor,
444
	 * expand the table.
445
	 */
446
	hashp->NKEYS++;
447
	if (do_expand ||
448
	    (hashp->NKEYS / (hashp->MAX_BUCKET + 1) > hashp->FFACTOR))
449
		return (__expand_table(hashp));
450
	return (0);
451
}
452
453
/*
454
 *
455
 * Returns:
456
 *	pointer on success
457
 *	NULL on error
458
 */
459
BUFHEAD *
460
__add_ovflpage(HTAB *hashp, BUFHEAD *bufp)
461
{
462
	u_int16_t *sp, ndx, ovfl_num;
463
#ifdef DEBUG1
464
	int tmp1, tmp2;
465
#endif
466
	sp = (u_int16_t *)bufp->page;
467
468
	/* Check if we are dynamically determining the fill factor */
469
	if (hashp->FFACTOR == DEF_FFACTOR) {
470
		hashp->FFACTOR = sp[0] >> 1;
471
		if (hashp->FFACTOR < MIN_FFACTOR)
472
			hashp->FFACTOR = MIN_FFACTOR;
473
	}
474
	bufp->flags |= BUF_MOD;
475
	ovfl_num = overflow_page(hashp);
476
#ifdef DEBUG1
477
	tmp1 = bufp->addr;
478
	tmp2 = bufp->ovfl ? bufp->ovfl->addr : 0;
479
#endif
480
	if (!ovfl_num || !(bufp->ovfl = __get_buf(hashp, ovfl_num, bufp, 1)))
481
		return (NULL);
482
	bufp->ovfl->flags |= BUF_MOD;
483
#ifdef DEBUG1
484
	(void)fprintf(stderr, "ADDOVFLPAGE: %d->ovfl was %d is now %d\n",
485
	    tmp1, tmp2, bufp->ovfl->addr);
486
#endif
487
	ndx = sp[0];
488
	/*
489
	 * Since a pair is allocated on a page only if there's room to add
490
	 * an overflow page, we know that the OVFL information will fit on
491
	 * the page.
492
	 */
493
	sp[ndx + 4] = OFFSET(sp);
494
	sp[ndx + 3] = FREESPACE(sp) - OVFLSIZE;
495
	sp[ndx + 1] = ovfl_num;
496
	sp[ndx + 2] = OVFLPAGE;
497
	sp[0] = ndx + 2;
498
#ifdef HASH_STATISTICS
499
	hash_overflows++;
500
#endif
501
	return (bufp->ovfl);
502
}
503
504
/*
505
 * Returns:
506
 *	 0 indicates SUCCESS
507
 *	-1 indicates FAILURE
508
 */
509
int
510
__get_page(HTAB *hashp, char *p, u_int32_t bucket, int is_bucket, int is_disk,
511
    int is_bitmap)
512
{
513
	int fd, page, size, rsize;
514
	u_int16_t *bp;
515
516
6666
	fd = hashp->fp;
517
3333
	size = hashp->BSIZE;
518
519
3333
	if ((fd == -1) || !is_disk) {
520
		PAGE_INIT(p);
521
		return (0);
522
	}
523
3333
	if (is_bucket)
524
8819
		page = BUCKET_TO_PAGE(bucket);
525
	else
526
		page = OADDR_TO_PAGE(bucket);
527
3333
	if ((rsize = pread(fd, p, size, (off_t)page << hashp->BSHIFT)) == -1)
528
		return (-1);
529
3333
	bp = (u_int16_t *)p;
530
3333
	if (!rsize)
531
		bp[0] = 0;	/* We hit the EOF, so initialize a new page */
532
	else
533
3333
		if (rsize != size) {
534
			errno = EFTYPE;
535
			return (-1);
536
		}
537

6666
	if (!is_bitmap && !bp[0]) {
538
		PAGE_INIT(p);
539
	} else
540
3333
		if (hashp->LORDER != BYTE_ORDER) {
541
			int i, max;
542
543
			if (is_bitmap) {
544
				max = hashp->BSIZE >> 2; /* divide by 4 */
545
				for (i = 0; i < max; i++)
546
					M_32_SWAP(((int *)p)[i]);
547
			} else {
548
				M_16_SWAP(bp[0]);
549
				max = bp[0] + 2;
550
				for (i = 1; i <= max; i++)
551
					M_16_SWAP(bp[i]);
552
			}
553
		}
554
3333
	return (0);
555
3333
}
556
557
/*
558
 * Write page p to disk
559
 *
560
 * Returns:
561
 *	 0 ==> OK
562
 *	-1 ==>failure
563
 */
564
int
565
__put_page(HTAB *hashp, char *p, u_int32_t bucket, int is_bucket, int is_bitmap)
566
{
567
	int fd, page, size, wsize;
568
569
	size = hashp->BSIZE;
570
	if ((hashp->fp == -1) && open_temp(hashp))
571
		return (-1);
572
	fd = hashp->fp;
573
574
	if (hashp->LORDER != BYTE_ORDER) {
575
		int i, max;
576
577
		if (is_bitmap) {
578
			max = hashp->BSIZE >> 2;	/* divide by 4 */
579
			for (i = 0; i < max; i++)
580
				M_32_SWAP(((int *)p)[i]);
581
		} else {
582
			max = ((u_int16_t *)p)[0] + 2;
583
			for (i = 0; i <= max; i++)
584
				M_16_SWAP(((u_int16_t *)p)[i]);
585
		}
586
	}
587
	if (is_bucket)
588
		page = BUCKET_TO_PAGE(bucket);
589
	else
590
		page = OADDR_TO_PAGE(bucket);
591
	if ((wsize = pwrite(fd, p, size, (off_t)page << hashp->BSHIFT)) == -1)
592
		/* Errno is set */
593
		return (-1);
594
	if (wsize != size) {
595
		errno = EFTYPE;
596
		return (-1);
597
	}
598
	return (0);
599
}
600
601
#define BYTE_MASK	((1 << INT_BYTE_SHIFT) -1)
602
/*
603
 * Initialize a new bitmap page.  Bitmap pages are left in memory
604
 * once they are read in.
605
 */
606
int
607
__ibitmap(HTAB *hashp, int pnum, int nbits, int ndx)
608
{
609
	u_int32_t *ip;
610
	int clearbytes, clearints;
611
612
	if ((ip = (u_int32_t *)malloc(hashp->BSIZE)) == NULL)
613
		return (1);
614
	hashp->nmaps++;
615
	clearints = ((nbits - 1) >> INT_BYTE_SHIFT) + 1;
616
	clearbytes = clearints << INT_TO_BYTE;
617
	(void)memset((char *)ip, 0, clearbytes);
618
	(void)memset(((char *)ip) + clearbytes, 0xFF,
619
	    hashp->BSIZE - clearbytes);
620
	ip[clearints - 1] = ALL_SET << (nbits & BYTE_MASK);
621
	SETBIT(ip, 0);
622
	hashp->BITMAPS[ndx] = (u_int16_t)pnum;
623
	hashp->mapp[ndx] = ip;
624
	return (0);
625
}
626
627
static u_int32_t
628
first_free(u_int32_t map)
629
{
630
	u_int32_t i, mask;
631
632
	mask = 0x1;
633
	for (i = 0; i < BITS_PER_MAP; i++) {
634
		if (!(mask & map))
635
			return (i);
636
		mask = mask << 1;
637
	}
638
	return (i);
639
}
640
641
static u_int16_t
642
overflow_page(HTAB *hashp)
643
{
644
	u_int32_t *freep;
645
	int max_free, offset, splitnum;
646
	u_int16_t addr;
647
	int bit, first_page, free_bit, free_page, i, in_use_bits, j;
648
#ifdef DEBUG2
649
	int tmp1, tmp2;
650
#endif
651
	splitnum = hashp->OVFL_POINT;
652
	max_free = hashp->SPARES[splitnum];
653
654
	free_page = (max_free - 1) >> (hashp->BSHIFT + BYTE_SHIFT);
655
	free_bit = (max_free - 1) & ((hashp->BSIZE << BYTE_SHIFT) - 1);
656
657
	/* Look through all the free maps to find the first free block */
658
	first_page = hashp->LAST_FREED >>(hashp->BSHIFT + BYTE_SHIFT);
659
	for ( i = first_page; i <= free_page; i++ ) {
660
		if (!(freep = (u_int32_t *)hashp->mapp[i]) &&
661
		    !(freep = fetch_bitmap(hashp, i)))
662
			return (0);
663
		if (i == free_page)
664
			in_use_bits = free_bit;
665
		else
666
			in_use_bits = (hashp->BSIZE << BYTE_SHIFT) - 1;
667
668
		if (i == first_page) {
669
			bit = hashp->LAST_FREED &
670
			    ((hashp->BSIZE << BYTE_SHIFT) - 1);
671
			j = bit / BITS_PER_MAP;
672
			bit = bit & ~(BITS_PER_MAP - 1);
673
		} else {
674
			bit = 0;
675
			j = 0;
676
		}
677
		for (; bit <= in_use_bits; j++, bit += BITS_PER_MAP)
678
			if (freep[j] != ALL_SET)
679
				goto found;
680
	}
681
682
	/* No Free Page Found */
683
	hashp->LAST_FREED = hashp->SPARES[splitnum];
684
	hashp->SPARES[splitnum]++;
685
	offset = hashp->SPARES[splitnum] -
686
	    (splitnum ? hashp->SPARES[splitnum - 1] : 0);
687
688
#define	OVMSG	"HASH: Out of overflow pages.  Increase page size\n"
689
	if (offset > SPLITMASK) {
690
		if (++splitnum >= NCACHED) {
691
			(void)write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1);
692
			errno = EFBIG;
693
			return (0);
694
		}
695
		hashp->OVFL_POINT = splitnum;
696
		hashp->SPARES[splitnum] = hashp->SPARES[splitnum-1];
697
		hashp->SPARES[splitnum-1]--;
698
		offset = 1;
699
	}
700
701
	/* Check if we need to allocate a new bitmap page */
702
	if (free_bit == (hashp->BSIZE << BYTE_SHIFT) - 1) {
703
		free_page++;
704
		if (free_page >= NCACHED) {
705
			(void)write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1);
706
			errno = EFBIG;
707
			return (0);
708
		}
709
		/*
710
		 * This is tricky.  The 1 indicates that you want the new page
711
		 * allocated with 1 clear bit.  Actually, you are going to
712
		 * allocate 2 pages from this map.  The first is going to be
713
		 * the map page, the second is the overflow page we were
714
		 * looking for.  The init_bitmap routine automatically, sets
715
		 * the first bit of itself to indicate that the bitmap itself
716
		 * is in use.  We would explicitly set the second bit, but
717
		 * don't have to if we tell init_bitmap not to leave it clear
718
		 * in the first place.
719
		 */
720
		if (__ibitmap(hashp,
721
		    (int)OADDR_OF(splitnum, offset), 1, free_page))
722
			return (0);
723
		hashp->SPARES[splitnum]++;
724
#ifdef DEBUG2
725
		free_bit = 2;
726
#endif
727
		offset++;
728
		if (offset > SPLITMASK) {
729
			if (++splitnum >= NCACHED) {
730
				(void)write(STDERR_FILENO, OVMSG,
731
				    sizeof(OVMSG) - 1);
732
				errno = EFBIG;
733
				return (0);
734
			}
735
			hashp->OVFL_POINT = splitnum;
736
			hashp->SPARES[splitnum] = hashp->SPARES[splitnum-1];
737
			hashp->SPARES[splitnum-1]--;
738
			offset = 0;
739
		}
740
	} else {
741
		/*
742
		 * Free_bit addresses the last used bit.  Bump it to address
743
		 * the first available bit.
744
		 */
745
		free_bit++;
746
		SETBIT(freep, free_bit);
747
	}
748
749
	/* Calculate address of the new overflow page */
750
	addr = OADDR_OF(splitnum, offset);
751
#ifdef DEBUG2
752
	(void)fprintf(stderr, "OVERFLOW_PAGE: ADDR: %d BIT: %d PAGE %d\n",
753
	    addr, free_bit, free_page);
754
#endif
755
	return (addr);
756
757
found:
758
	bit = bit + first_free(freep[j]);
759
	SETBIT(freep, bit);
760
#ifdef DEBUG2
761
	tmp1 = bit;
762
	tmp2 = i;
763
#endif
764
	/*
765
	 * Bits are addressed starting with 0, but overflow pages are addressed
766
	 * beginning at 1. Bit is a bit addressnumber, so we need to increment
767
	 * it to convert it to a page number.
768
	 */
769
	bit = 1 + bit + (i * (hashp->BSIZE << BYTE_SHIFT));
770
	if (bit >= hashp->LAST_FREED)
771
		hashp->LAST_FREED = bit - 1;
772
773
	/* Calculate the split number for this page */
774
	for (i = 0; (i < splitnum) && (bit > hashp->SPARES[i]); i++);
775
	offset = (i ? bit - hashp->SPARES[i - 1] : bit);
776
	if (offset >= SPLITMASK) {
777
		(void)write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1);
778
		errno = EFBIG;
779
		return (0);	/* Out of overflow pages */
780
	}
781
	addr = OADDR_OF(i, offset);
782
#ifdef DEBUG2
783
	(void)fprintf(stderr, "OVERFLOW_PAGE: ADDR: %d BIT: %d PAGE %d\n",
784
	    addr, tmp1, tmp2);
785
#endif
786
787
	/* Allocate and return the overflow page */
788
	return (addr);
789
}
790
791
/*
792
 * Mark this overflow page as free.
793
 */
794
void
795
__free_ovflpage(HTAB *hashp, BUFHEAD *obufp)
796
{
797
	u_int16_t addr;
798
	u_int32_t *freep;
799
	int bit_address, free_page, free_bit;
800
	u_int16_t ndx;
801
802
	addr = obufp->addr;
803
#ifdef DEBUG1
804
	(void)fprintf(stderr, "Freeing %d\n", addr);
805
#endif
806
	ndx = (((u_int16_t)addr) >> SPLITSHIFT);
807
	bit_address =
808
	    (ndx ? hashp->SPARES[ndx - 1] : 0) + (addr & SPLITMASK) - 1;
809
	 if (bit_address < hashp->LAST_FREED)
810
		hashp->LAST_FREED = bit_address;
811
	free_page = (bit_address >> (hashp->BSHIFT + BYTE_SHIFT));
812
	free_bit = bit_address & ((hashp->BSIZE << BYTE_SHIFT) - 1);
813
814
	if (!(freep = hashp->mapp[free_page]))
815
		freep = fetch_bitmap(hashp, free_page);
816
#ifdef DEBUG
817
	/*
818
	 * This had better never happen.  It means we tried to read a bitmap
819
	 * that has already had overflow pages allocated off it, and we
820
	 * failed to read it from the file.
821
	 */
822
	if (!freep)
823
		assert(0);
824
#endif
825
	CLRBIT(freep, free_bit);
826
#ifdef DEBUG2
827
	(void)fprintf(stderr, "FREE_OVFLPAGE: ADDR: %d BIT: %d PAGE %d\n",
828
	    obufp->addr, free_bit, free_page);
829
#endif
830
	__reclaim_buf(hashp, obufp);
831
}
832
833
/*
834
 * Returns:
835
 *	 0 success
836
 *	-1 failure
837
 */
838
static int
839
open_temp(HTAB *hashp)
840
{
841
	sigset_t set, oset;
842
	int len;
843
	char *envtmp = NULL;
844
	char path[PATH_MAX];
845
846
	if (issetugid() == 0)
847
		envtmp = getenv("TMPDIR");
848
	len = snprintf(path,
849
	    sizeof(path), "%s/_hash.XXXXXX", envtmp ? envtmp : "/tmp");
850
	if (len < 0 || len >= sizeof(path)) {
851
		errno = ENAMETOOLONG;
852
		return (-1);
853
	}
854
855
	/* Block signals; make sure file goes away at process exit. */
856
	(void)sigfillset(&set);
857
	(void)sigprocmask(SIG_BLOCK, &set, &oset);
858
	if ((hashp->fp = mkostemp(path, O_CLOEXEC)) != -1) {
859
		(void)unlink(path);
860
	}
861
	(void)sigprocmask(SIG_SETMASK, &oset, (sigset_t *)NULL);
862
	return (hashp->fp != -1 ? 0 : -1);
863
}
864
865
/*
866
 * We have to know that the key will fit, but the last entry on the page is
867
 * an overflow pair, so we need to shift things.
868
 */
869
static void
870
squeeze_key(u_int16_t *sp, const DBT *key, const DBT *val)
871
{
872
	char *p;
873
	u_int16_t free_space, n, off, pageno;
874
875
	p = (char *)sp;
876
	n = sp[0];
877
	free_space = FREESPACE(sp);
878
	off = OFFSET(sp);
879
880
	pageno = sp[n - 1];
881
	off -= key->size;
882
	sp[n - 1] = off;
883
	memmove(p + off, key->data, key->size);
884
	off -= val->size;
885
	sp[n] = off;
886
	memmove(p + off, val->data, val->size);
887
	sp[0] = n + 2;
888
	sp[n + 1] = pageno;
889
	sp[n + 2] = OVFLPAGE;
890
	FREESPACE(sp) = free_space - PAIRSIZE(key, val);
891
	OFFSET(sp) = off;
892
}
893
894
static u_int32_t *
895
fetch_bitmap(HTAB *hashp, int ndx)
896
{
897
	if (ndx >= hashp->nmaps)
898
		return (NULL);
899
	if ((hashp->mapp[ndx] = (u_int32_t *)malloc(hashp->BSIZE)) == NULL)
900
		return (NULL);
901
	if (__get_page(hashp,
902
	    (char *)hashp->mapp[ndx], hashp->BITMAPS[ndx], 0, 1, 1)) {
903
		free(hashp->mapp[ndx]);
904
		return (NULL);
905
	}
906
	return (hashp->mapp[ndx]);
907
}
908
909
#ifdef DEBUG4
910
int
911
print_chain(int addr)
912
{
913
	BUFHEAD *bufp;
914
	short *bp, oaddr;
915
916
	(void)fprintf(stderr, "%d ", addr);
917
	bufp = __get_buf(hashp, addr, NULL, 0);
918
	bp = (short *)bufp->page;
919
	while (bp[0] && ((bp[bp[0]] == OVFLPAGE) ||
920
		((bp[0] > 2) && bp[2] < REAL_KEY))) {
921
		oaddr = bp[bp[0] - 1];
922
		(void)fprintf(stderr, "%d ", (int)oaddr);
923
		bufp = __get_buf(hashp, (int)oaddr, bufp, 0);
924
		bp = (short *)bufp->page;
925
	}
926
	(void)fprintf(stderr, "\n");
927
}
928
#endif