/*- * Copyright (c) 1990, 1993, 1994 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Margo Seltzer. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #if defined(LIBC_SCCS) && !defined(lint) static char sccsid[] = "@(#)hash_page.c 8.7 (Berkeley) 8/16/94"; #endif /* LIBC_SCCS and not lint */ #include __FBSDID("$FreeBSD: src/lib/libc/db/hash/hash_page.c,v 1.16 2009/03/28 06:30:43 delphij Exp $"); /* * PACKAGE: hashing * * DESCRIPTION: * Page manipulation for hashing package. * * ROUTINES: * * External * __get_page * __add_ovflpage * Internal * overflow_page * open_temp */ #include "namespace.h" #include #include #include #include #include #include #include #include #ifdef DEBUG #include #endif #include "un-namespace.h" #include #include "hash.h" #include "page.h" #include "hash_extern.h" static u_int32_t *fetch_bitmap(HTAB *, int); static u_int32_t first_free(u_int32_t); static int open_temp(HTAB *); static u_int16_t overflow_page(HTAB *); static void putpair(char *, const DBT *, const DBT *); static void squeeze_key(u_int16_t *, const DBT *, const DBT *); static int ugly_split(HTAB *, u_int32_t, BUFHEAD *, BUFHEAD *, int, int); #define PAGE_INIT(P) { \ ((u_int16_t *)(P))[0] = 0; \ ((u_int16_t *)(P))[1] = hashp->BSIZE - 3 * sizeof(u_int16_t); \ ((u_int16_t *)(P))[2] = hashp->BSIZE; \ } /* * This is called AFTER we have verified that there is room on the page for * the pair (PAIRFITS has returned true) so we go right ahead and start moving * stuff on. */ static void putpair(char *p, const DBT *key, const DBT *val) { u_int16_t *bp, n, off; bp = (u_int16_t *)p; /* Enter the key first. */ n = bp[0]; off = OFFSET(bp) - key->size; memmove(p + off, key->data, key->size); bp[++n] = off; /* Now the data. */ off -= val->size; memmove(p + off, val->data, val->size); bp[++n] = off; /* Adjust page info. */ bp[0] = n; bp[n + 1] = off - ((n + 3) * sizeof(u_int16_t)); bp[n + 2] = off; } /* * Returns: * 0 OK * -1 error */ int __delpair(HTAB *hashp, BUFHEAD *bufp, int ndx) { u_int16_t *bp, newoff, pairlen; int n; bp = (u_int16_t *)bufp->page; n = bp[0]; if (bp[ndx + 1] < REAL_KEY) return (__big_delete(hashp, bufp)); if (ndx != 1) newoff = bp[ndx - 1]; else newoff = hashp->BSIZE; pairlen = newoff - bp[ndx + 1]; if (ndx != (n - 1)) { /* Hard Case -- need to shuffle keys */ int i; char *src = bufp->page + (int)OFFSET(bp); char *dst = src + (int)pairlen; memmove(dst, src, bp[ndx + 1] - OFFSET(bp)); /* Now adjust the pointers */ for (i = ndx + 2; i <= n; i += 2) { if (bp[i + 1] == OVFLPAGE) { bp[i - 2] = bp[i]; bp[i - 1] = bp[i + 1]; } else { bp[i - 2] = bp[i] + pairlen; bp[i - 1] = bp[i + 1] + pairlen; } } if (ndx == hashp->cndx) { /* * We just removed pair we were "pointing" to. * By moving back the cndx we ensure subsequent * hash_seq() calls won't skip over any entries. */ hashp->cndx -= 2; } } /* Finally adjust the page data */ bp[n] = OFFSET(bp) + pairlen; bp[n - 1] = bp[n + 1] + pairlen + 2 * sizeof(u_int16_t); bp[0] = n - 2; hashp->NKEYS--; bufp->flags |= BUF_MOD; return (0); } /* * Returns: * 0 ==> OK * -1 ==> Error */ int __split_page(HTAB *hashp, u_int32_t obucket, u_int32_t nbucket) { BUFHEAD *new_bufp, *old_bufp; u_int16_t *ino; char *np; DBT key, val; int n, ndx, retval; u_int16_t copyto, diff, off, moved; char *op; copyto = (u_int16_t)hashp->BSIZE; off = (u_int16_t)hashp->BSIZE; old_bufp = __get_buf(hashp, obucket, NULL, 0); if (old_bufp == NULL) return (-1); new_bufp = __get_buf(hashp, nbucket, NULL, 0); if (new_bufp == NULL) return (-1); old_bufp->flags |= (BUF_MOD | BUF_PIN); new_bufp->flags |= (BUF_MOD | BUF_PIN); ino = (u_int16_t *)(op = old_bufp->page); np = new_bufp->page; moved = 0; for (n = 1, ndx = 1; n < ino[0]; n += 2) { if (ino[n + 1] < REAL_KEY) { retval = ugly_split(hashp, obucket, old_bufp, new_bufp, (int)copyto, (int)moved); old_bufp->flags &= ~BUF_PIN; new_bufp->flags &= ~BUF_PIN; return (retval); } key.data = (u_char *)op + ino[n]; key.size = off - ino[n]; if (__call_hash(hashp, key.data, key.size) == obucket) { /* Don't switch page */ diff = copyto - off; if (diff) { copyto = ino[n + 1] + diff; memmove(op + copyto, op + ino[n + 1], off - ino[n + 1]); ino[ndx] = copyto + ino[n] - ino[n + 1]; ino[ndx + 1] = copyto; } else copyto = ino[n + 1]; ndx += 2; } else { /* Switch page */ val.data = (u_char *)op + ino[n + 1]; val.size = ino[n] - ino[n + 1]; putpair(np, &key, &val); moved += 2; } off = ino[n + 1]; } /* Now clean up the page */ ino[0] -= moved; FREESPACE(ino) = copyto - sizeof(u_int16_t) * (ino[0] + 3); OFFSET(ino) = copyto; #ifdef DEBUG3 (void)fprintf(stderr, "split %d/%d\n", ((u_int16_t *)np)[0] / 2, ((u_int16_t *)op)[0] / 2); #endif /* unpin both pages */ old_bufp->flags &= ~BUF_PIN; new_bufp->flags &= ~BUF_PIN; return (0); } /* * Called when we encounter an overflow or big key/data page during split * handling. This is special cased since we have to begin checking whether * the key/data pairs fit on their respective pages and because we may need * overflow pages for both the old and new pages. * * The first page might be a page with regular key/data pairs in which case * we have a regular overflow condition and just need to go on to the next * page or it might be a big key/data pair in which case we need to fix the * big key/data pair. * * Returns: * 0 ==> success * -1 ==> failure */ static int ugly_split(HTAB *hashp, u_int32_t obucket, /* Same as __split_page. */ BUFHEAD *old_bufp, BUFHEAD *new_bufp, int copyto, /* First byte on page which contains key/data values. */ int moved) /* Number of pairs moved to new page. */ { BUFHEAD *bufp; /* Buffer header for ino */ u_int16_t *ino; /* Page keys come off of */ u_int16_t *np; /* New page */ u_int16_t *op; /* Page keys go on to if they aren't moving */ BUFHEAD *last_bfp; /* Last buf header OVFL needing to be freed */ DBT key, val; SPLIT_RETURN ret; u_int16_t n, off, ov_addr, scopyto; char *cino; /* Character value of ino */ bufp = old_bufp; ino = (u_int16_t *)old_bufp->page; np = (u_int16_t *)new_bufp->page; op = (u_int16_t *)old_bufp->page; last_bfp = NULL; scopyto = (u_int16_t)copyto; /* ANSI */ n = ino[0] - 1; while (n < ino[0]) { if (ino[2] < REAL_KEY && ino[2] != OVFLPAGE) { if (__big_split(hashp, old_bufp, new_bufp, bufp, bufp->addr, obucket, &ret)) return (-1); old_bufp = ret.oldp; if (!old_bufp) return (-1); op = (u_int16_t *)old_bufp->page; new_bufp = ret.newp; if (!new_bufp) return (-1); np = (u_int16_t *)new_bufp->page; bufp = ret.nextp; if (!bufp) return (0); cino = (char *)bufp->page; ino = (u_int16_t *)cino; last_bfp = ret.nextp; } else if (ino[n + 1] == OVFLPAGE) { ov_addr = ino[n]; /* * Fix up the old page -- the extra 2 are the fields * which contained the overflow information. */ ino[0] -= (moved + 2); FREESPACE(ino) = scopyto - sizeof(u_int16_t) * (ino[0] + 3); OFFSET(ino) = scopyto; bufp = __get_buf(hashp, ov_addr, bufp, 0); if (!bufp) return (-1); ino = (u_int16_t *)bufp->page; n = 1; scopyto = hashp->BSIZE; moved = 0; if (last_bfp) __free_ovflpage(hashp, last_bfp); last_bfp = bufp; } /* Move regular sized pairs of there are any */ off = hashp->BSIZE; for (n = 1; (n < ino[0]) && (ino[n + 1] >= REAL_KEY); n += 2) { cino = (char *)ino; key.data = (u_char *)cino + ino[n]; key.size = off - ino[n]; val.data = (u_char *)cino + ino[n + 1]; val.size = ino[n] - ino[n + 1]; off = ino[n + 1]; if (__call_hash(hashp, key.data, key.size) == obucket) { /* Keep on old page */ if (PAIRFITS(op, (&key), (&val))) putpair((char *)op, &key, &val); else { old_bufp = __add_ovflpage(hashp, old_bufp); if (!old_bufp) return (-1); op = (u_int16_t *)old_bufp->page; putpair((char *)op, &key, &val); } old_bufp->flags |= BUF_MOD; } else { /* Move to new page */ if (PAIRFITS(np, (&key), (&val))) putpair((char *)np, &key, &val); else { new_bufp = __add_ovflpage(hashp, new_bufp); if (!new_bufp) return (-1); np = (u_int16_t *)new_bufp->page; putpair((char *)np, &key, &val); } new_bufp->flags |= BUF_MOD; } } } if (last_bfp) __free_ovflpage(hashp, last_bfp); return (0); } /* * Add the given pair to the page * * Returns: * 0 ==> OK * 1 ==> failure */ int __addel(HTAB *hashp, BUFHEAD *bufp, const DBT *key, const DBT *val) { u_int16_t *bp, *sop; int do_expand; bp = (u_int16_t *)bufp->page; do_expand = 0; while (bp[0] && (bp[2] < REAL_KEY || bp[bp[0]] < REAL_KEY)) /* Exception case */ if (bp[2] == FULL_KEY_DATA && bp[0] == 2) /* This is the last page of a big key/data pair and we need to add another page */ break; else if (bp[2] < REAL_KEY && bp[bp[0]] != OVFLPAGE) { bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0); if (!bufp) return (-1); bp = (u_int16_t *)bufp->page; } else if (bp[bp[0]] != OVFLPAGE) { /* Short key/data pairs, no more pages */ break; } else { /* Try to squeeze key on this page */ if (bp[2] >= REAL_KEY && FREESPACE(bp) >= PAIRSIZE(key, val)) { squeeze_key(bp, key, val); goto stats; } else { bufp = __get_buf(hashp, bp[bp[0] - 1], bufp, 0); if (!bufp) return (-1); bp = (u_int16_t *)bufp->page; } } if (PAIRFITS(bp, key, val)) putpair(bufp->page, key, val); else { do_expand = 1; bufp = __add_ovflpage(hashp, bufp); if (!bufp) return (-1); sop = (u_int16_t *)bufp->page; if (PAIRFITS(sop, key, val)) putpair((char *)sop, key, val); else if (__big_insert(hashp, bufp, key, val)) return (-1); } stats: bufp->flags |= BUF_MOD; /* * If the average number of keys per bucket exceeds the fill factor, * expand the table. */ hashp->NKEYS++; if (do_expand || (hashp->NKEYS / (hashp->MAX_BUCKET + 1) > hashp->FFACTOR)) return (__expand_table(hashp)); return (0); } /* * * Returns: * pointer on success * NULL on error */ BUFHEAD * __add_ovflpage(HTAB *hashp, BUFHEAD *bufp) { u_int16_t *sp, ndx, ovfl_num; #ifdef DEBUG1 int tmp1, tmp2; #endif sp = (u_int16_t *)bufp->page; /* Check if we are dynamically determining the fill factor */ if (hashp->FFACTOR == DEF_FFACTOR) { hashp->FFACTOR = sp[0] >> 1; if (hashp->FFACTOR < MIN_FFACTOR) hashp->FFACTOR = MIN_FFACTOR; } bufp->flags |= BUF_MOD; ovfl_num = overflow_page(hashp); #ifdef DEBUG1 tmp1 = bufp->addr; tmp2 = bufp->ovfl ? bufp->ovfl->addr : 0; #endif if (!ovfl_num || !(bufp->ovfl = __get_buf(hashp, ovfl_num, bufp, 1))) return (NULL); bufp->ovfl->flags |= BUF_MOD; #ifdef DEBUG1 (void)fprintf(stderr, "ADDOVFLPAGE: %d->ovfl was %d is now %d\n", tmp1, tmp2, bufp->ovfl->addr); #endif ndx = sp[0]; /* * Since a pair is allocated on a page only if there's room to add * an overflow page, we know that the OVFL information will fit on * the page. */ sp[ndx + 4] = OFFSET(sp); sp[ndx + 3] = FREESPACE(sp) - OVFLSIZE; sp[ndx + 1] = ovfl_num; sp[ndx + 2] = OVFLPAGE; sp[0] = ndx + 2; #ifdef HASH_STATISTICS hash_overflows++; #endif return (bufp->ovfl); } /* * Returns: * 0 indicates SUCCESS * -1 indicates FAILURE */ int __get_page(HTAB *hashp, char *p, u_int32_t bucket, int is_bucket, int is_disk, int is_bitmap) { int fd, page, size, rsize; u_int16_t *bp; fd = hashp->fp; size = hashp->BSIZE; if ((fd == -1) || !is_disk) { PAGE_INIT(p); return (0); } if (is_bucket) page = BUCKET_TO_PAGE(bucket); else page = OADDR_TO_PAGE(bucket); if ((rsize = pread(fd, p, size, (off_t)page << hashp->BSHIFT)) == -1) return (-1); bp = (u_int16_t *)p; if (!rsize) bp[0] = 0; /* We hit the EOF, so initialize a new page */ else if (rsize != size) { errno = EFTYPE; return (-1); } if (!is_bitmap && !bp[0]) { PAGE_INIT(p); } else if (hashp->LORDER != BYTE_ORDER) { int i, max; if (is_bitmap) { max = hashp->BSIZE >> 2; /* divide by 4 */ for (i = 0; i < max; i++) M_32_SWAP(((int *)p)[i]); } else { M_16_SWAP(bp[0]); max = bp[0] + 2; for (i = 1; i <= max; i++) M_16_SWAP(bp[i]); } } return (0); } /* * Write page p to disk * * Returns: * 0 ==> OK * -1 ==>failure */ int __put_page(HTAB *hashp, char *p, u_int32_t bucket, int is_bucket, int is_bitmap) { int fd, page, size, wsize, max; size = hashp->BSIZE; if ((hashp->fp == -1) && open_temp(hashp)) return (-1); fd = hashp->fp; if (hashp->LORDER != BYTE_ORDER) { int i; if (is_bitmap) { max = hashp->BSIZE >> 2; /* divide by 4 */ for (i = 0; i < max; i++) M_32_SWAP(((int *)p)[i]); } else { max = ((u_int16_t *)p)[0] + 2; for (i = 0; i <= max; i++) M_16_SWAP(((u_int16_t *)p)[i]); } } if (is_bucket) page = BUCKET_TO_PAGE(bucket); else page = OADDR_TO_PAGE(bucket); if ((wsize = pwrite(fd, p, size, (off_t)page << hashp->BSHIFT)) == -1) /* Errno is set */ return (-1); if (wsize != size) { errno = EFTYPE; return (-1); } /* 4485533 - reswap the in-memory copy */ if (hashp->LORDER != BYTE_ORDER) { int i; if (is_bitmap) { for (i = 0; i < max; i++) M_32_SWAP(((int *)p)[i]); } else { for (i = 0; i <= max; i++) M_16_SWAP(((u_int16_t *)p)[i]); } } return (0); } #define BYTE_MASK ((1 << INT_BYTE_SHIFT) -1) /* * Initialize a new bitmap page. Bitmap pages are left in memory * once they are read in. */ int __ibitmap(HTAB *hashp, int pnum, int nbits, int ndx) { u_int32_t *ip; int clearbytes, clearints; if ((ip = (u_int32_t *)malloc(hashp->BSIZE)) == NULL) return (1); hashp->nmaps++; clearints = ((nbits - 1) >> INT_BYTE_SHIFT) + 1; clearbytes = clearints << INT_TO_BYTE; (void)memset((char *)ip, 0, clearbytes); (void)memset(((char *)ip) + clearbytes, 0xFF, hashp->BSIZE - clearbytes); ip[clearints - 1] = ALL_SET << (nbits & BYTE_MASK); SETBIT(ip, 0); hashp->BITMAPS[ndx] = (u_int16_t)pnum; hashp->mapp[ndx] = ip; return (0); } static u_int32_t first_free(u_int32_t map) { u_int32_t i, mask; mask = 0x1; for (i = 0; i < BITS_PER_MAP; i++) { if (!(mask & map)) return (i); mask = mask << 1; } return (i); } static u_int16_t overflow_page(HTAB *hashp) { u_int32_t *freep; int max_free, offset, splitnum; u_int16_t addr; int bit, first_page, free_bit, free_page, i, in_use_bits, j; #ifdef DEBUG2 int tmp1, tmp2; #endif splitnum = hashp->OVFL_POINT; max_free = hashp->SPARES[splitnum]; free_page = (max_free - 1) >> (hashp->BSHIFT + BYTE_SHIFT); free_bit = (max_free - 1) & ((hashp->BSIZE << BYTE_SHIFT) - 1); /* Look through all the free maps to find the first free block */ first_page = hashp->LAST_FREED >>(hashp->BSHIFT + BYTE_SHIFT); for ( i = first_page; i <= free_page; i++ ) { if (!(freep = (u_int32_t *)hashp->mapp[i]) && !(freep = fetch_bitmap(hashp, i))) return (0); if (i == free_page) in_use_bits = free_bit; else in_use_bits = (hashp->BSIZE << BYTE_SHIFT) - 1; if (i == first_page) { bit = hashp->LAST_FREED & ((hashp->BSIZE << BYTE_SHIFT) - 1); j = bit / BITS_PER_MAP; bit = bit & ~(BITS_PER_MAP - 1); } else { bit = 0; j = 0; } for (; bit <= in_use_bits; j++, bit += BITS_PER_MAP) if (freep[j] != ALL_SET) goto found; } /* No Free Page Found */ hashp->LAST_FREED = hashp->SPARES[splitnum]; hashp->SPARES[splitnum]++; offset = hashp->SPARES[splitnum] - (splitnum ? hashp->SPARES[splitnum - 1] : 0); #define OVMSG "HASH: Out of overflow pages. Increase page size\n" if (offset > SPLITMASK) { if (++splitnum >= NCACHED) { (void)_write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1); errno = EFBIG; return (0); } hashp->OVFL_POINT = splitnum; hashp->SPARES[splitnum] = hashp->SPARES[splitnum-1]; hashp->SPARES[splitnum-1]--; offset = 1; } /* Check if we need to allocate a new bitmap page */ if (free_bit == (hashp->BSIZE << BYTE_SHIFT) - 1) { free_page++; if (free_page >= NCACHED) { (void)_write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1); errno = EFBIG; return (0); } /* * This is tricky. The 1 indicates that you want the new page * allocated with 1 clear bit. Actually, you are going to * allocate 2 pages from this map. The first is going to be * the map page, the second is the overflow page we were * looking for. The init_bitmap routine automatically, sets * the first bit of itself to indicate that the bitmap itself * is in use. We would explicitly set the second bit, but * don't have to if we tell init_bitmap not to leave it clear * in the first place. */ if (__ibitmap(hashp, (int)OADDR_OF(splitnum, offset), 1, free_page)) return (0); hashp->SPARES[splitnum]++; #ifdef DEBUG2 free_bit = 2; #endif offset++; if (offset > SPLITMASK) { if (++splitnum >= NCACHED) { (void)_write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1); errno = EFBIG; return (0); } hashp->OVFL_POINT = splitnum; hashp->SPARES[splitnum] = hashp->SPARES[splitnum-1]; hashp->SPARES[splitnum-1]--; offset = 0; } } else { /* * Free_bit addresses the last used bit. Bump it to address * the first available bit. */ free_bit++; SETBIT(freep, free_bit); } /* Calculate address of the new overflow page */ addr = OADDR_OF(splitnum, offset); #ifdef DEBUG2 (void)fprintf(stderr, "OVERFLOW_PAGE: ADDR: %d BIT: %d PAGE %d\n", addr, free_bit, free_page); #endif return (addr); found: bit = bit + first_free(freep[j]); SETBIT(freep, bit); #ifdef DEBUG2 tmp1 = bit; tmp2 = i; #endif /* * Bits are addressed starting with 0, but overflow pages are addressed * beginning at 1. Bit is a bit addressnumber, so we need to increment * it to convert it to a page number. */ bit = 1 + bit + (i * (hashp->BSIZE << BYTE_SHIFT)); if (bit >= hashp->LAST_FREED) hashp->LAST_FREED = bit - 1; /* Calculate the split number for this page */ for (i = 0; (i < splitnum) && (bit > hashp->SPARES[i]); i++); offset = (i ? bit - hashp->SPARES[i - 1] : bit); if (offset >= SPLITMASK) { (void)_write(STDERR_FILENO, OVMSG, sizeof(OVMSG) - 1); errno = EFBIG; return (0); /* Out of overflow pages */ } addr = OADDR_OF(i, offset); #ifdef DEBUG2 (void)fprintf(stderr, "OVERFLOW_PAGE: ADDR: %d BIT: %d PAGE %d\n", addr, tmp1, tmp2); #endif /* Allocate and return the overflow page */ return (addr); } /* * Mark this overflow page as free. */ void __free_ovflpage(HTAB *hashp, BUFHEAD *obufp) { u_int16_t addr; u_int32_t *freep; int bit_address, free_page, free_bit; u_int16_t ndx; addr = obufp->addr; #ifdef DEBUG1 (void)fprintf(stderr, "Freeing %d\n", addr); #endif ndx = (((u_int16_t)addr) >> SPLITSHIFT); bit_address = (ndx ? hashp->SPARES[ndx - 1] : 0) + (addr & SPLITMASK) - 1; if (bit_address < hashp->LAST_FREED) hashp->LAST_FREED = bit_address; free_page = (bit_address >> (hashp->BSHIFT + BYTE_SHIFT)); free_bit = bit_address & ((hashp->BSIZE << BYTE_SHIFT) - 1); if (!(freep = hashp->mapp[free_page])) freep = fetch_bitmap(hashp, free_page); #ifdef DEBUG /* * This had better never happen. It means we tried to read a bitmap * that has already had overflow pages allocated off it, and we * failed to read it from the file. */ if (!freep) assert(0); #endif CLRBIT(freep, free_bit); #ifdef DEBUG2 (void)fprintf(stderr, "FREE_OVFLPAGE: ADDR: %d BIT: %d PAGE %d\n", obufp->addr, free_bit, free_page); #endif __reclaim_buf(hashp, obufp); } /* * Returns: * 0 success * -1 failure */ static int open_temp(HTAB *hashp) { sigset_t set, oset; int len; char *envtmp = NULL; char path[MAXPATHLEN]; if (issetugid() == 0) envtmp = getenv("TMPDIR"); len = snprintf(path, sizeof(path), "%s/_hash.XXXXXX", envtmp ? envtmp : "/tmp"); if (len < 0 || len >= sizeof(path)) { errno = ENAMETOOLONG; return (-1); } /* Block signals; make sure file goes away at process exit. */ (void)sigfillset(&set); (void)_sigprocmask(SIG_BLOCK, &set, &oset); if ((hashp->fp = mkstemp(path)) != -1) { (void)unlink(path); (void)_fcntl(hashp->fp, F_SETFD, 1); } (void)_sigprocmask(SIG_SETMASK, &oset, (sigset_t *)NULL); return (hashp->fp != -1 ? 0 : -1); } /* * We have to know that the key will fit, but the last entry on the page is * an overflow pair, so we need to shift things. */ static void squeeze_key(u_int16_t *sp, const DBT *key, const DBT *val) { char *p; u_int16_t free_space, n, off, pageno; p = (char *)sp; n = sp[0]; free_space = FREESPACE(sp); off = OFFSET(sp); pageno = sp[n - 1]; off -= key->size; sp[n - 1] = off; memmove(p + off, key->data, key->size); off -= val->size; sp[n] = off; memmove(p + off, val->data, val->size); sp[0] = n + 2; sp[n + 1] = pageno; sp[n + 2] = OVFLPAGE; FREESPACE(sp) = free_space - PAIRSIZE(key, val); OFFSET(sp) = off; } static u_int32_t * fetch_bitmap(HTAB *hashp, int ndx) { if (ndx >= hashp->nmaps) return (NULL); if ((hashp->mapp[ndx] = (u_int32_t *)malloc(hashp->BSIZE)) == NULL) return (NULL); if (__get_page(hashp, (char *)hashp->mapp[ndx], hashp->BITMAPS[ndx], 0, 1, 1)) { free(hashp->mapp[ndx]); return (NULL); } return (hashp->mapp[ndx]); } #ifdef DEBUG4 int print_chain(int addr) { BUFHEAD *bufp; short *bp, oaddr; (void)fprintf(stderr, "%d ", addr); bufp = __get_buf(hashp, addr, NULL, 0); bp = (short *)bufp->page; while (bp[0] && ((bp[bp[0]] == OVFLPAGE) || ((bp[0] > 2) && bp[2] < REAL_KEY))) { oaddr = bp[bp[0] - 1]; (void)fprintf(stderr, "%d ", (int)oaddr); bufp = __get_buf(hashp, (int)oaddr, bufp, 0); bp = (short *)bufp->page; } (void)fprintf(stderr, "\n"); } #endif