| /*- |
| * 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. |
| * 3. ***REMOVED*** - see |
| * ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change |
| * 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(unix) |
| #define MY_LSEEK lseek |
| #else |
| #define MY_LSEEK new_lseek |
| extern long new_lseek(int fd, long pos, int start); |
| #endif |
| |
| #if defined(LIBC_SCCS) && !defined(lint) |
| static char sccsid[] = "@(#)hash_page.c 8.7 (Berkeley) 8/16/94"; |
| #endif /* LIBC_SCCS and not lint */ |
| |
| /* |
| * PACKAGE: hashing |
| * |
| * DESCRIPTION: |
| * Page manipulation for hashing package. |
| * |
| * ROUTINES: |
| * |
| * External |
| * __get_page |
| * __add_ovflpage |
| * Internal |
| * overflow_page |
| * open_temp |
| */ |
| #ifndef macintosh |
| #include <sys/types.h> |
| #endif |
| |
| #if defined(macintosh) |
| #include <unistd.h> |
| #endif |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #if defined(_WIN32) || defined(_WINDOWS) |
| #include <io.h> |
| #endif |
| #include <signal.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| |
| #if !defined(_WIN32) && !defined(_WINDOWS) && !defined(macintosh) |
| #include <unistd.h> |
| #endif |
| |
| #include <assert.h> |
| |
| #include "mcom_db.h" |
| #include "hash.h" |
| #include "page.h" |
| /* #include "extern.h" */ |
| |
| extern int mkstempflags(char *path, int extraFlags); |
| |
| static uint32 *fetch_bitmap(HTAB *, uint32); |
| static uint32 first_free(uint32); |
| static int open_temp(HTAB *); |
| static uint16 overflow_page(HTAB *); |
| static void squeeze_key(uint16 *, const DBT *, const DBT *); |
| static int ugly_split(HTAB *, uint32, BUFHEAD *, BUFHEAD *, int, int); |
| |
| #define PAGE_INIT(P) \ |
| { \ |
| ((uint16 *)(P))[0] = 0; \ |
| ((uint16 *)(P))[1] = hashp->BSIZE - 3 * sizeof(uint16); \ |
| ((uint16 *)(P))[2] = hashp->BSIZE; \ |
| } |
| |
| /* implement a new lseek using lseek that |
| * writes zero's when extending a file |
| * beyond the end. |
| */ |
| long |
| new_lseek(int fd, long offset, int origin) |
| { |
| long cur_pos = 0; |
| long end_pos = 0; |
| long seek_pos = 0; |
| |
| if (origin == SEEK_CUR) { |
| if (offset < 1) |
| return (lseek(fd, offset, SEEK_CUR)); |
| |
| cur_pos = lseek(fd, 0, SEEK_CUR); |
| |
| if (cur_pos < 0) |
| return (cur_pos); |
| } |
| |
| end_pos = lseek(fd, 0, SEEK_END); |
| if (end_pos < 0) |
| return (end_pos); |
| |
| if (origin == SEEK_SET) |
| seek_pos = offset; |
| else if (origin == SEEK_CUR) |
| seek_pos = cur_pos + offset; |
| else if (origin == SEEK_END) |
| seek_pos = end_pos + offset; |
| else { |
| assert(0); |
| return (-1); |
| } |
| |
| /* the seek position desired is before the |
| * end of the file. We don't need |
| * to do anything special except the seek. |
| */ |
| if (seek_pos <= end_pos) |
| return (lseek(fd, seek_pos, SEEK_SET)); |
| |
| /* the seek position is beyond the end of the |
| * file. Write zero's to the end. |
| * |
| * we are already at the end of the file so |
| * we just need to "write()" zeros for the |
| * difference between seek_pos-end_pos and |
| * then seek to the position to finish |
| * the call |
| */ |
| { |
| char buffer[1024]; |
| long len = seek_pos - end_pos; |
| memset(buffer, 0, 1024); |
| while (len > 0) { |
| if (write(fd, buffer, (size_t)(1024 > len ? len : 1024)) < 0) |
| return (-1); |
| len -= 1024; |
| } |
| return (lseek(fd, seek_pos, SEEK_SET)); |
| } |
| } |
| |
| /* |
| * 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, DBT *val) |
| { |
| register uint16 *bp, n, off; |
| |
| bp = (uint16 *)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(uint16)); |
| bp[n + 2] = off; |
| } |
| |
| /* |
| * Returns: |
| * 0 OK |
| * -1 error |
| */ |
| extern int |
| dbm_delpair(HTAB *hashp, BUFHEAD *bufp, int ndx) |
| { |
| register uint16 *bp, newoff; |
| register int n; |
| uint16 pairlen; |
| |
| bp = (uint16 *)bufp->page; |
| n = bp[0]; |
| |
| if (bp[ndx + 1] < REAL_KEY) |
| return (dbm_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 */ |
| register int i; |
| register char *src = bufp->page + (int)OFFSET(bp); |
| uint32 dst_offset = (uint32)OFFSET(bp) + (uint32)pairlen; |
| register char *dst = bufp->page + dst_offset; |
| uint32 length = bp[ndx + 1] - OFFSET(bp); |
| |
| /* |
| * +-----------+XXX+---------+XXX+---------+---------> +infinity |
| * | | | | |
| * 0 src_offset dst_offset BSIZE |
| * |
| * Dst_offset is > src_offset, so if src_offset were bad, dst_offset |
| * would be too, therefore we check only dst_offset. |
| * |
| * If dst_offset is >= BSIZE, either OFFSET(bp), or pairlen, or both |
| * is corrupted. |
| * |
| * Once we know dst_offset is < BSIZE, we can subtract it from BSIZE |
| * to get an upper bound on length. |
| */ |
| if (dst_offset > (uint32)hashp->BSIZE) |
| return (DATABASE_CORRUPTED_ERROR); |
| |
| if (length > (uint32)(hashp->BSIZE - dst_offset)) |
| return (DATABASE_CORRUPTED_ERROR); |
| |
| memmove(dst, src, length); |
| |
| /* 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; |
| } |
| } |
| } |
| /* Finally adjust the page data */ |
| bp[n] = OFFSET(bp) + pairlen; |
| bp[n - 1] = bp[n + 1] + pairlen + 2 * sizeof(uint16); |
| bp[0] = n - 2; |
| hashp->NKEYS--; |
| |
| bufp->flags |= BUF_MOD; |
| return (0); |
| } |
| /* |
| * Returns: |
| * 0 ==> OK |
| * -1 ==> Error |
| */ |
| extern int |
| dbm_split_page(HTAB *hashp, uint32 obucket, uint32 nbucket) |
| { |
| register BUFHEAD *new_bufp, *old_bufp; |
| register uint16 *ino; |
| register uint16 *tmp_uint16_array; |
| register char *np; |
| DBT key, val; |
| uint16 n, ndx; |
| int retval; |
| uint16 copyto, diff, moved; |
| size_t off; |
| char *op; |
| |
| copyto = (uint16)hashp->BSIZE; |
| off = (uint16)hashp->BSIZE; |
| old_bufp = dbm_get_buf(hashp, obucket, NULL, 0); |
| if (old_bufp == NULL) |
| return (-1); |
| new_bufp = dbm_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 = (uint16 *)(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 = (uint8 *)op + ino[n]; |
| |
| /* check here for ino[n] being greater than |
| * off. If it is then the database has |
| * been corrupted. |
| */ |
| if (ino[n] > off) |
| return (DATABASE_CORRUPTED_ERROR); |
| |
| key.size = off - ino[n]; |
| |
| #ifdef DEBUG |
| /* make sure the size is positive */ |
| assert(((int)key.size) > -1); |
| #endif |
| |
| if (dbm_call_hash(hashp, (char *)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 = (uint8 *)op + ino[n + 1]; |
| val.size = ino[n] - ino[n + 1]; |
| |
| /* if the pair doesn't fit something is horribly |
| * wrong. LJM |
| */ |
| tmp_uint16_array = (uint16 *)np; |
| if (!PAIRFITS(tmp_uint16_array, &key, &val)) |
| return (DATABASE_CORRUPTED_ERROR); |
| |
| putpair(np, &key, &val); |
| moved += 2; |
| } |
| |
| off = ino[n + 1]; |
| } |
| |
| /* Now clean up the page */ |
| ino[0] -= moved; |
| FREESPACE(ino) = copyto - sizeof(uint16) * (ino[0] + 3); |
| OFFSET(ino) = copyto; |
| |
| #ifdef DEBUG3 |
| (void)fprintf(stderr, "split %d/%d\n", |
| ((uint16 *)np)[0] / 2, |
| ((uint16 *)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 |
| */ |
| |
| /* the maximum number of loops we will allow UGLY split to chew |
| * on before we assume the database is corrupted and throw it |
| * away. |
| */ |
| #define MAX_UGLY_SPLIT_LOOPS 10000 |
| |
| static int |
| ugly_split(HTAB *hashp, uint32 obucket, BUFHEAD *old_bufp, |
| BUFHEAD *new_bufp, /* Same as __split_page. */ int copyto, int moved) |
| /* int copyto; First byte on page which contains key/data values. */ |
| /* int moved; Number of pairs moved to new page. */ |
| { |
| register BUFHEAD *bufp; /* Buffer header for ino */ |
| register uint16 *ino; /* Page keys come off of */ |
| register uint16 *np; /* New page */ |
| register uint16 *op; /* Page keys go on to if they aren't moving */ |
| uint32 loop_detection = 0; |
| |
| BUFHEAD *last_bfp; /* Last buf header OVFL needing to be freed */ |
| DBT key, val; |
| SPLIT_RETURN ret; |
| uint16 n, off, ov_addr, scopyto; |
| char *cino; /* Character value of ino */ |
| int status; |
| |
| bufp = old_bufp; |
| ino = (uint16 *)old_bufp->page; |
| np = (uint16 *)new_bufp->page; |
| op = (uint16 *)old_bufp->page; |
| last_bfp = NULL; |
| scopyto = (uint16)copyto; /* ANSI */ |
| |
| if (ino[0] < 1) { |
| return DATABASE_CORRUPTED_ERROR; |
| } |
| n = ino[0] - 1; |
| while (n < ino[0]) { |
| |
| /* this function goes nuts sometimes and never returns. |
| * I havent found the problem yet but I need a solution |
| * so if we loop too often we assume a database curruption error |
| * :LJM |
| */ |
| loop_detection++; |
| |
| if (loop_detection > MAX_UGLY_SPLIT_LOOPS) |
| return DATABASE_CORRUPTED_ERROR; |
| |
| if (ino[2] < REAL_KEY && ino[2] != OVFLPAGE) { |
| if ((status = dbm_big_split(hashp, old_bufp, |
| new_bufp, bufp, bufp->addr, obucket, &ret))) |
| return (status); |
| old_bufp = ret.oldp; |
| if (!old_bufp) |
| return (-1); |
| op = (uint16 *)old_bufp->page; |
| new_bufp = ret.newp; |
| if (!new_bufp) |
| return (-1); |
| np = (uint16 *)new_bufp->page; |
| bufp = ret.nextp; |
| if (!bufp) |
| return (0); |
| cino = (char *)bufp->page; |
| ino = (uint16 *)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. |
| */ |
| if (ino[0] < (moved + 2)) { |
| return DATABASE_CORRUPTED_ERROR; |
| } |
| ino[0] -= (moved + 2); |
| if (scopyto < sizeof(uint16) * (ino[0] + 3)) { |
| return DATABASE_CORRUPTED_ERROR; |
| } |
| FREESPACE(ino) = |
| scopyto - sizeof(uint16) * (ino[0] + 3); |
| OFFSET(ino) = scopyto; |
| |
| bufp = dbm_get_buf(hashp, ov_addr, bufp, 0); |
| if (!bufp) |
| return (-1); |
| |
| ino = (uint16 *)bufp->page; |
| n = 1; |
| scopyto = hashp->BSIZE; |
| moved = 0; |
| |
| if (last_bfp) |
| dbm_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 = (uint8 *)cino + ino[n]; |
| if (off < ino[n]) { |
| return DATABASE_CORRUPTED_ERROR; |
| } |
| key.size = off - ino[n]; |
| val.data = (uint8 *)cino + ino[n + 1]; |
| if (ino[n] < ino[n + 1]) { |
| return DATABASE_CORRUPTED_ERROR; |
| } |
| val.size = ino[n] - ino[n + 1]; |
| off = ino[n + 1]; |
| |
| if (dbm_call_hash(hashp, (char *)key.data, key.size) == obucket) { |
| /* Keep on old page */ |
| if (PAIRFITS(op, (&key), (&val))) |
| putpair((char *)op, &key, &val); |
| else { |
| old_bufp = |
| dbm_add_ovflpage(hashp, old_bufp); |
| if (!old_bufp) |
| return (-1); |
| op = (uint16 *)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 = |
| dbm_add_ovflpage(hashp, new_bufp); |
| if (!new_bufp) |
| return (-1); |
| np = (uint16 *)new_bufp->page; |
| putpair((char *)np, &key, &val); |
| } |
| new_bufp->flags |= BUF_MOD; |
| } |
| } |
| } |
| if (last_bfp) |
| dbm_free_ovflpage(hashp, last_bfp); |
| return (0); |
| } |
| |
| /* |
| * Add the given pair to the page |
| * |
| * Returns: |
| * 0 ==> OK |
| * 1 ==> failure |
| */ |
| extern int |
| dbm_addel(HTAB *hashp, BUFHEAD *bufp, const DBT *key, const DBT *val) |
| { |
| register uint16 *bp, *sop; |
| int do_expand; |
| |
| bp = (uint16 *)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 = dbm_get_buf(hashp, bp[bp[0] - 1], bufp, 0); |
| if (!bufp) { |
| #ifdef DEBUG |
| assert(0); |
| #endif |
| return (-1); |
| } |
| bp = (uint16 *)bufp->page; |
| } else |
| /* Try to squeeze key on this page */ |
| if (FREESPACE(bp) > PAIRSIZE(key, val)) { |
| { |
| squeeze_key(bp, key, val); |
| |
| /* LJM: I added this because I think it was |
| * left out on accident. |
| * if this isn't incremented nkeys will not |
| * be the actual number of keys in the db. |
| */ |
| hashp->NKEYS++; |
| return (0); |
| } |
| } else { |
| bufp = dbm_get_buf(hashp, bp[bp[0] - 1], bufp, 0); |
| if (!bufp) { |
| #ifdef DEBUG |
| assert(0); |
| #endif |
| return (-1); |
| } |
| bp = (uint16 *)bufp->page; |
| } |
| |
| if (PAIRFITS(bp, key, val)) |
| putpair(bufp->page, key, (DBT *)val); |
| else { |
| do_expand = 1; |
| bufp = dbm_add_ovflpage(hashp, bufp); |
| if (!bufp) { |
| #ifdef DEBUG |
| assert(0); |
| #endif |
| return (-1); |
| } |
| sop = (uint16 *)bufp->page; |
| |
| if (PAIRFITS(sop, key, val)) |
| putpair((char *)sop, key, (DBT *)val); |
| else if (dbm_big_insert(hashp, bufp, key, val)) { |
| #ifdef DEBUG |
| assert(0); |
| #endif |
| return (-1); |
| } |
| } |
| 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 (dbm_expand_table(hashp)); |
| return (0); |
| } |
| |
| /* |
| * |
| * Returns: |
| * pointer on success |
| * NULL on error |
| */ |
| extern BUFHEAD * |
| dbm_add_ovflpage(HTAB *hashp, BUFHEAD *bufp) |
| { |
| register uint16 *sp; |
| uint16 ndx, ovfl_num; |
| #ifdef DEBUG1 |
| int tmp1, tmp2; |
| #endif |
| sp = (uint16 *)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 = dbm_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 |
| */ |
| extern int |
| dbm_get_page(HTAB *hashp, |
| char *p, |
| uint32 bucket, |
| int is_bucket, |
| int is_disk, |
| int is_bitmap) |
| { |
| register int fd, page; |
| size_t size; |
| int rsize; |
| uint16 *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 ((MY_LSEEK(fd, (off_t)page << hashp->BSHIFT, SEEK_SET) == -1) || |
| ((rsize = read(fd, p, size)) == -1)) |
| return (-1); |
| |
| bp = (uint16 *)p; |
| if (!rsize) |
| bp[0] = 0; /* We hit the EOF, so initialize a new page */ |
| else if ((unsigned)rsize != size) { |
| errno = EFTYPE; |
| return (-1); |
| } |
| |
| if (!is_bitmap && !bp[0]) { |
| PAGE_INIT(p); |
| } else { |
| |
| if (hashp->LORDER != BYTE_ORDER) { |
| register 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; |
| |
| /* bound the size of max by |
| * the maximum number of entries |
| * in the array |
| */ |
| if ((unsigned)max > (size / sizeof(uint16))) |
| return (DATABASE_CORRUPTED_ERROR); |
| |
| /* do the byte order swap |
| */ |
| for (i = 1; i <= max; i++) |
| M_16_SWAP(bp[i]); |
| } |
| } |
| |
| /* check the validity of the page here |
| * (after doing byte order swaping if necessary) |
| */ |
| if (!is_bitmap && bp[0] != 0) { |
| uint16 num_keys = bp[0]; |
| uint16 offset; |
| uint16 i; |
| |
| /* bp[0] is supposed to be the number of |
| * entries currently in the page. If |
| * bp[0] is too large (larger than the whole |
| * page) then the page is corrupted |
| */ |
| if (bp[0] > (size / sizeof(uint16))) |
| return (DATABASE_CORRUPTED_ERROR); |
| |
| /* bound free space */ |
| if (FREESPACE(bp) > size) |
| return (DATABASE_CORRUPTED_ERROR); |
| |
| /* check each key and data offset to make |
| * sure they are all within bounds they |
| * should all be less than the previous |
| * offset as well. |
| */ |
| offset = size; |
| for (i = 1; i <= num_keys; i += 2) { |
| /* ignore overflow pages etc. */ |
| if (bp[i + 1] >= REAL_KEY) { |
| |
| if (bp[i] > offset || bp[i + 1] > bp[i]) |
| return (DATABASE_CORRUPTED_ERROR); |
| |
| offset = bp[i + 1]; |
| } else { |
| /* there are no other valid keys after |
| * seeing a non REAL_KEY |
| */ |
| break; |
| } |
| } |
| } |
| } |
| return (0); |
| } |
| |
| /* |
| * Write page p to disk |
| * |
| * Returns: |
| * 0 ==> OK |
| * -1 ==>failure |
| */ |
| extern int |
| dbm_put_page(HTAB *hashp, char *p, uint32 bucket, int is_bucket, int is_bitmap) |
| { |
| register int fd, page; |
| size_t size; |
| int wsize; |
| off_t offset; |
| |
| size = hashp->BSIZE; |
| if ((hashp->fp == -1) && open_temp(hashp)) |
| return (-1); |
| fd = hashp->fp; |
| |
| if (hashp->LORDER != BYTE_ORDER) { |
| register int i; |
| register int max; |
| |
| if (is_bitmap) { |
| max = hashp->BSIZE >> 2; /* divide by 4 */ |
| for (i = 0; i < max; i++) |
| M_32_SWAP(((int *)p)[i]); |
| } else { |
| max = ((uint16 *)p)[0] + 2; |
| |
| /* bound the size of max by |
| * the maximum number of entries |
| * in the array |
| */ |
| if ((unsigned)max > (size / sizeof(uint16))) |
| return (DATABASE_CORRUPTED_ERROR); |
| |
| for (i = 0; i <= max; i++) |
| M_16_SWAP(((uint16 *)p)[i]); |
| } |
| } |
| |
| if (is_bucket) |
| page = BUCKET_TO_PAGE(bucket); |
| else |
| page = OADDR_TO_PAGE(bucket); |
| offset = (off_t)page << hashp->BSHIFT; |
| if ((MY_LSEEK(fd, offset, SEEK_SET) == -1) || |
| ((wsize = write(fd, p, size)) == -1)) |
| /* Errno is set */ |
| return (-1); |
| if ((unsigned)wsize != size) { |
| errno = EFTYPE; |
| return (-1); |
| } |
| #if defined(_WIN32) || defined(_WINDOWS) |
| if (offset + size > hashp->file_size) { |
| hashp->updateEOF = 1; |
| } |
| #endif |
| /* put the page back the way it was so that it isn't byteswapped |
| * if it remains in memory - LJM |
| */ |
| if (hashp->LORDER != BYTE_ORDER) { |
| register int i; |
| register int max; |
| |
| if (is_bitmap) { |
| max = hashp->BSIZE >> 2; /* divide by 4 */ |
| for (i = 0; i < max; i++) |
| M_32_SWAP(((int *)p)[i]); |
| } else { |
| uint16 *bp = (uint16 *)p; |
| |
| M_16_SWAP(bp[0]); |
| max = bp[0] + 2; |
| |
| /* no need to bound the size if max again |
| * since it was done already above |
| */ |
| |
| /* do the byte order re-swap |
| */ |
| for (i = 1; i <= max; i++) |
| M_16_SWAP(bp[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. |
| */ |
| extern int |
| dbm_ibitmap(HTAB *hashp, int pnum, int nbits, int ndx) |
| { |
| uint32 *ip; |
| size_t clearbytes, clearints; |
| |
| if ((ip = (uint32 *)malloc((size_t)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] = (uint16)pnum; |
| hashp->mapp[ndx] = ip; |
| return (0); |
| } |
| |
| static uint32 |
| first_free(uint32 map) |
| { |
| register uint32 i, mask; |
| |
| mask = 0x1; |
| for (i = 0; i < BITS_PER_MAP; i++) { |
| if (!(mask & map)) |
| return (i); |
| mask = mask << 1; |
| } |
| return (i); |
| } |
| |
| static uint16 |
| overflow_page(HTAB *hashp) |
| { |
| register uint32 *freep = NULL; |
| register int max_free, offset, splitnum; |
| uint16 addr; |
| uint32 i; |
| int bit, first_page, free_bit, free_page, 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 <= (unsigned)free_page; i++) { |
| if (!(freep = (uint32 *)hashp->mapp[i]) && |
| !(freep = fetch_bitmap(hashp, i))) |
| return (0); |
| if (i == (unsigned)free_page) |
| in_use_bits = free_bit; |
| else |
| in_use_bits = (hashp->BSIZE << BYTE_SHIFT) - 1; |
| |
| if (i == (unsigned)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) { |
| #ifndef macintosh |
| (void)fwrite(OVMSG, 1, sizeof(OVMSG) - 1, stderr); |
| #endif |
| 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) { |
| #ifndef macintosh |
| (void)fwrite(OVMSG, 1, sizeof(OVMSG) - 1, stderr); |
| #endif |
| 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 (dbm_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) { |
| #ifndef macintosh |
| (void)fwrite(OVMSG, 1, sizeof(OVMSG) - 1, stderr); |
| #endif |
| 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 < (unsigned)splitnum) && (bit > hashp->SPARES[i]); i++) { |
| } |
| offset = (i ? bit - hashp->SPARES[i - 1] : bit); |
| if (offset >= SPLITMASK) |
| 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. |
| */ |
| extern void |
| dbm_free_ovflpage(HTAB *hashp, BUFHEAD *obufp) |
| { |
| uint16 addr; |
| uint32 *freep; |
| uint32 bit_address, free_page, free_bit; |
| uint16 ndx; |
| |
| if (!obufp || !obufp->addr) |
| return; |
| |
| addr = obufp->addr; |
| #ifdef DEBUG1 |
| (void)fprintf(stderr, "Freeing %d\n", addr); |
| #endif |
| ndx = (((uint16)addr) >> SPLITSHIFT); |
| bit_address = |
| (ndx ? hashp->SPARES[ndx - 1] : 0) + (addr & SPLITMASK) - 1; |
| if (bit_address < (uint32)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); |
| return; |
| } |
| #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 |
| dbm_reclaim_buf(hashp, obufp); |
| } |
| |
| /* |
| * Returns: |
| * 0 success |
| * -1 failure |
| */ |
| static int |
| open_temp(HTAB *hashp) |
| { |
| #ifdef XP_OS2 |
| hashp->fp = mkstemp(NULL); |
| #else |
| #if !defined(_WIN32) && !defined(_WINDOWS) && !defined(macintosh) |
| sigset_t set, oset; |
| #endif |
| #if !defined(macintosh) |
| char *tmpdir; |
| size_t len; |
| char last; |
| #endif |
| static const char namestr[] = "/_hashXXXXXX"; |
| char filename[1024]; |
| |
| #if !defined(_WIN32) && !defined(_WINDOWS) && !defined(macintosh) |
| /* Block signals; make sure file goes away at process exit. */ |
| (void)sigfillset(&set); |
| (void)sigprocmask(SIG_BLOCK, &set, &oset); |
| #endif |
| |
| filename[0] = 0; |
| #if defined(macintosh) |
| strcat(filename, namestr + 1); |
| #else |
| tmpdir = getenv("TMP"); |
| if (!tmpdir) |
| tmpdir = getenv("TMPDIR"); |
| if (!tmpdir) |
| tmpdir = getenv("TEMP"); |
| if (!tmpdir) |
| tmpdir = "."; |
| len = strlen(tmpdir); |
| if (len && len < (sizeof filename - sizeof namestr)) { |
| strcpy(filename, tmpdir); |
| } |
| len = strlen(filename); |
| last = tmpdir[len - 1]; |
| strcat(filename, (last == '/' || last == '\\') ? namestr + 1 : namestr); |
| #endif |
| |
| #if defined(_WIN32) || defined(_WINDOWS) |
| if ((hashp->fp = mkstempflags(filename, _O_BINARY | _O_TEMPORARY)) != -1) { |
| if (hashp->filename) { |
| free(hashp->filename); |
| } |
| hashp->filename = strdup(filename); |
| hashp->is_temp = 1; |
| } |
| #else |
| if ((hashp->fp = mkstemp(filename)) != -1) { |
| (void)unlink(filename); |
| #if !defined(macintosh) |
| (void)fcntl(hashp->fp, F_SETFD, 1); |
| #endif |
| } |
| #endif |
| |
| #if !defined(_WIN32) && !defined(_WINDOWS) && !defined(macintosh) |
| (void)sigprocmask(SIG_SETMASK, &oset, (sigset_t *)NULL); |
| #endif |
| #endif /* !OS2 */ |
| 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(uint16 *sp, const DBT *key, const DBT *val) |
| { |
| register char *p; |
| uint16 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 uint32 * |
| fetch_bitmap(HTAB *hashp, uint32 ndx) |
| { |
| if (ndx >= (unsigned)hashp->nmaps) |
| return (NULL); |
| if ((hashp->mapp[ndx] = (uint32 *)malloc((size_t)hashp->BSIZE)) == NULL) |
| return (NULL); |
| if (dbm_get_page(hashp, |
| (char *)hashp->mapp[ndx], hashp->BITMAPS[ndx], 0, 1, 1)) { |
| free(hashp->mapp[ndx]); |
| hashp->mapp[ndx] = NULL; /* NEW: 9-11-95 */ |
| return (NULL); |
| } |
| return (hashp->mapp[ndx]); |
| } |
| |
| #ifdef DEBUG4 |
| int |
| print_chain(int addr) |
| { |
| BUFHEAD *bufp; |
| short *bp, oaddr; |
| |
| (void)fprintf(stderr, "%d ", addr); |
| bufp = dbm_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 = dbm_get_buf(hashp, (int)oaddr, bufp, 0); |
| bp = (short *)bufp->page; |
| } |
| (void)fprintf(stderr, "\n"); |
| } |
| #endif |
