| /* Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| /* |
| * sdbm - ndbm work-alike hashed database library |
| * based on Per-Aake Larson's Dynamic Hashing algorithms. BIT 18 (1978). |
| * author: oz@nexus.yorku.ca |
| * ex-public domain, ported to APR for Apache 2 |
| * core routines |
| */ |
| |
| #include "apr.h" |
| #include "apr_file_io.h" |
| #include "apr_strings.h" |
| #include "apr_errno.h" |
| #include "apr_sdbm.h" |
| |
| #include "sdbm_tune.h" |
| #include "sdbm_pair.h" |
| #include "sdbm_private.h" |
| |
| #include <string.h> /* for memset() */ |
| #include <stdlib.h> /* for malloc() and free() */ |
| |
| /* |
| * forward |
| */ |
| static int getdbit (apr_sdbm_t *, long); |
| static apr_status_t setdbit(apr_sdbm_t *, long); |
| static apr_status_t getpage(apr_sdbm_t *db, long); |
| static apr_status_t getnext(apr_sdbm_datum_t *key, apr_sdbm_t *db); |
| static apr_status_t makroom(apr_sdbm_t *, long, int); |
| |
| /* |
| * useful macros |
| */ |
| #define bad(x) ((x).dptr == NULL || (x).dsize <= 0) |
| #define exhash(item) sdbm_hash((item).dptr, (item).dsize) |
| |
| /* ### Does anything need these externally? */ |
| #define sdbm_dirfno(db) ((db)->dirf) |
| #define sdbm_pagfno(db) ((db)->pagf) |
| |
| #define OFF_PAG(off) (apr_off_t) (off) * PBLKSIZ |
| #define OFF_DIR(off) (apr_off_t) (off) * DBLKSIZ |
| |
| static long masks[] = { |
| 000000000000, 000000000001, 000000000003, 000000000007, |
| 000000000017, 000000000037, 000000000077, 000000000177, |
| 000000000377, 000000000777, 000000001777, 000000003777, |
| 000000007777, 000000017777, 000000037777, 000000077777, |
| 000000177777, 000000377777, 000000777777, 000001777777, |
| 000003777777, 000007777777, 000017777777, 000037777777, |
| 000077777777, 000177777777, 000377777777, 000777777777, |
| 001777777777, 003777777777, 007777777777, 017777777777 |
| }; |
| |
| const apr_sdbm_datum_t sdbm_nullitem = { NULL, 0 }; |
| |
| static apr_status_t database_cleanup(void *data) |
| { |
| apr_sdbm_t *db = data; |
| |
| /* |
| * Can't rely on apr_sdbm_unlock, since it will merely |
| * decrement the refcnt if several locks are held. |
| */ |
| if (db->flags & (SDBM_SHARED_LOCK | SDBM_EXCLUSIVE_LOCK)) |
| (void) apr_file_unlock(db->dirf); |
| (void) apr_file_close(db->dirf); |
| (void) apr_file_close(db->pagf); |
| free(db); |
| |
| return APR_SUCCESS; |
| } |
| |
| static apr_status_t prep(apr_sdbm_t **pdb, const char *dirname, const char *pagname, |
| apr_int32_t flags, apr_fileperms_t perms, apr_pool_t *p) |
| { |
| apr_sdbm_t *db; |
| apr_status_t status; |
| |
| *pdb = NULL; |
| |
| db = malloc(sizeof(*db)); |
| memset(db, 0, sizeof(*db)); |
| |
| db->pool = p; |
| |
| /* |
| * adjust user flags so that WRONLY becomes RDWR, |
| * as required by this package. Also set our internal |
| * flag for RDONLY if needed. |
| */ |
| if (!(flags & APR_WRITE)) { |
| db->flags |= SDBM_RDONLY; |
| } |
| |
| /* |
| * adjust the file open flags so that we handle locking |
| * on our own (don't rely on any locking behavior within |
| * an apr_file_t, in case it's ever introduced, and set |
| * our own flag. |
| */ |
| if (flags & APR_SHARELOCK) { |
| db->flags |= SDBM_SHARED; |
| flags &= ~APR_SHARELOCK; |
| } |
| |
| flags |= APR_BINARY | APR_READ; |
| |
| /* |
| * open the files in sequence, and stat the dirfile. |
| * If we fail anywhere, undo everything, return NULL. |
| */ |
| |
| if ((status = apr_file_open(&db->dirf, dirname, flags, perms, p)) |
| != APR_SUCCESS) |
| goto error; |
| |
| if ((status = apr_file_open(&db->pagf, pagname, flags, perms, p)) |
| != APR_SUCCESS) |
| goto error; |
| |
| if ((status = apr_sdbm_lock(db, (db->flags & SDBM_RDONLY) |
| ? APR_FLOCK_SHARED |
| : APR_FLOCK_EXCLUSIVE)) |
| != APR_SUCCESS) |
| goto error; |
| |
| /* apr_pcalloc zeroed the buffers |
| * apr_sdbm_lock stated the dirf->size and invalidated the cache |
| */ |
| |
| /* |
| * if we are opened in SHARED mode, unlock ourself |
| */ |
| if (db->flags & SDBM_SHARED) |
| if ((status = apr_sdbm_unlock(db)) != APR_SUCCESS) |
| goto error; |
| |
| /* make sure that we close the database at some point */ |
| apr_pool_cleanup_register(p, db, database_cleanup, apr_pool_cleanup_null); |
| |
| /* Done! */ |
| *pdb = db; |
| return APR_SUCCESS; |
| |
| error: |
| if (db->dirf && db->pagf) |
| (void) apr_sdbm_unlock(db); |
| if (db->dirf != NULL) |
| (void) apr_file_close(db->dirf); |
| if (db->pagf != NULL) { |
| (void) apr_file_close(db->pagf); |
| } |
| free(db); |
| return status; |
| } |
| |
| APU_DECLARE(apr_status_t) apr_sdbm_open(apr_sdbm_t **db, const char *file, |
| apr_int32_t flags, |
| apr_fileperms_t perms, apr_pool_t *p) |
| { |
| char *dirname = apr_pstrcat(p, file, APR_SDBM_DIRFEXT, NULL); |
| char *pagname = apr_pstrcat(p, file, APR_SDBM_PAGFEXT, NULL); |
| |
| return prep(db, dirname, pagname, flags, perms, p); |
| } |
| |
| APU_DECLARE(apr_status_t) apr_sdbm_close(apr_sdbm_t *db) |
| { |
| return apr_pool_cleanup_run(db->pool, db, database_cleanup); |
| } |
| |
| APU_DECLARE(apr_status_t) apr_sdbm_fetch(apr_sdbm_t *db, apr_sdbm_datum_t *val, |
| apr_sdbm_datum_t key) |
| { |
| apr_status_t status; |
| |
| if (db == NULL || bad(key)) |
| return APR_EINVAL; |
| |
| if ((status = apr_sdbm_lock(db, APR_FLOCK_SHARED)) != APR_SUCCESS) |
| return status; |
| |
| if ((status = getpage(db, exhash(key))) == APR_SUCCESS) { |
| *val = getpair(db->pagbuf, key); |
| /* ### do we want a not-found result? */ |
| } |
| |
| (void) apr_sdbm_unlock(db); |
| |
| return status; |
| } |
| |
| static apr_status_t write_page(apr_sdbm_t *db, const char *buf, long pagno) |
| { |
| apr_status_t status; |
| apr_off_t off = OFF_PAG(pagno); |
| |
| if ((status = apr_file_seek(db->pagf, APR_SET, &off)) == APR_SUCCESS) |
| status = apr_file_write_full(db->pagf, buf, PBLKSIZ, NULL); |
| |
| return status; |
| } |
| |
| APU_DECLARE(apr_status_t) apr_sdbm_delete(apr_sdbm_t *db, |
| const apr_sdbm_datum_t key) |
| { |
| apr_status_t status; |
| |
| if (db == NULL || bad(key)) |
| return APR_EINVAL; |
| if (apr_sdbm_rdonly(db)) |
| return APR_EINVAL; |
| |
| if ((status = apr_sdbm_lock(db, APR_FLOCK_EXCLUSIVE)) != APR_SUCCESS) |
| return status; |
| |
| if ((status = getpage(db, exhash(key))) == APR_SUCCESS) { |
| if (!delpair(db->pagbuf, key)) |
| /* ### should we define some APRUTIL codes? */ |
| status = APR_EGENERAL; |
| else |
| status = write_page(db, db->pagbuf, db->pagbno); |
| } |
| |
| (void) apr_sdbm_unlock(db); |
| |
| return status; |
| } |
| |
| APU_DECLARE(apr_status_t) apr_sdbm_store(apr_sdbm_t *db, apr_sdbm_datum_t key, |
| apr_sdbm_datum_t val, int flags) |
| { |
| int need; |
| register long hash; |
| apr_status_t status; |
| |
| if (db == NULL || bad(key)) |
| return APR_EINVAL; |
| if (apr_sdbm_rdonly(db)) |
| return APR_EINVAL; |
| need = key.dsize + val.dsize; |
| /* |
| * is the pair too big (or too small) for this database ?? |
| */ |
| if (need < 0 || need > PAIRMAX) |
| return APR_EINVAL; |
| |
| if ((status = apr_sdbm_lock(db, APR_FLOCK_EXCLUSIVE)) != APR_SUCCESS) |
| return status; |
| |
| if ((status = getpage(db, (hash = exhash(key)))) == APR_SUCCESS) { |
| |
| /* |
| * if we need to replace, delete the key/data pair |
| * first. If it is not there, ignore. |
| */ |
| if (flags == APR_SDBM_REPLACE) |
| (void) delpair(db->pagbuf, key); |
| else if (!(flags & APR_SDBM_INSERTDUP) && duppair(db->pagbuf, key)) { |
| status = APR_EEXIST; |
| goto error; |
| } |
| /* |
| * if we do not have enough room, we have to split. |
| */ |
| if (!fitpair(db->pagbuf, need)) |
| if ((status = makroom(db, hash, need)) != APR_SUCCESS) |
| goto error; |
| /* |
| * we have enough room or split is successful. insert the key, |
| * and update the page file. |
| */ |
| (void) putpair(db->pagbuf, key, val); |
| |
| status = write_page(db, db->pagbuf, db->pagbno); |
| } |
| |
| error: |
| (void) apr_sdbm_unlock(db); |
| |
| return status; |
| } |
| |
| /* |
| * makroom - make room by splitting the overfull page |
| * this routine will attempt to make room for SPLTMAX times before |
| * giving up. |
| */ |
| static apr_status_t makroom(apr_sdbm_t *db, long hash, int need) |
| { |
| long newp; |
| char twin[PBLKSIZ]; |
| char *pag = db->pagbuf; |
| char *new = twin; |
| register int smax = SPLTMAX; |
| apr_status_t status; |
| |
| do { |
| /* |
| * split the current page |
| */ |
| (void) splpage(pag, new, db->hmask + 1); |
| /* |
| * address of the new page |
| */ |
| newp = (hash & db->hmask) | (db->hmask + 1); |
| |
| /* |
| * write delay, read avoidence/cache shuffle: |
| * select the page for incoming pair: if key is to go to the new page, |
| * write out the previous one, and copy the new one over, thus making |
| * it the current page. If not, simply write the new page, and we are |
| * still looking at the page of interest. current page is not updated |
| * here, as sdbm_store will do so, after it inserts the incoming pair. |
| */ |
| if (hash & (db->hmask + 1)) { |
| if ((status = write_page(db, db->pagbuf, db->pagbno)) |
| != APR_SUCCESS) |
| return status; |
| |
| db->pagbno = newp; |
| (void) memcpy(pag, new, PBLKSIZ); |
| } |
| else { |
| if ((status = write_page(db, new, newp)) != APR_SUCCESS) |
| return status; |
| } |
| |
| if ((status = setdbit(db, db->curbit)) != APR_SUCCESS) |
| return status; |
| /* |
| * see if we have enough room now |
| */ |
| if (fitpair(pag, need)) |
| return APR_SUCCESS; |
| /* |
| * try again... update curbit and hmask as getpage would have |
| * done. because of our update of the current page, we do not |
| * need to read in anything. BUT we have to write the current |
| * [deferred] page out, as the window of failure is too great. |
| */ |
| db->curbit = 2 * db->curbit |
| + ((hash & (db->hmask + 1)) ? 2 : 1); |
| db->hmask |= db->hmask + 1; |
| |
| if ((status = write_page(db, db->pagbuf, db->pagbno)) |
| != APR_SUCCESS) |
| return status; |
| |
| } while (--smax); |
| |
| /* |
| * if we are here, this is real bad news. After SPLTMAX splits, |
| * we still cannot fit the key. say goodnight. |
| */ |
| #if 0 |
| (void) write(2, "sdbm: cannot insert after SPLTMAX attempts.\n", 44); |
| #endif |
| /* ### ENOSPC not really appropriate but better than nothing */ |
| return APR_ENOSPC; |
| |
| } |
| |
| /* Reads 'len' bytes from file 'f' at offset 'off' into buf. |
| * 'off' is given relative to the start of the file. |
| * If EOF is returned while reading, this is taken as success. |
| */ |
| static apr_status_t read_from(apr_file_t *f, void *buf, |
| apr_off_t off, apr_size_t len) |
| { |
| apr_status_t status; |
| |
| if ((status = apr_file_seek(f, APR_SET, &off)) != APR_SUCCESS || |
| ((status = apr_file_read_full(f, buf, len, NULL)) != APR_SUCCESS)) { |
| /* if EOF is reached, pretend we read all zero's */ |
| if (status == APR_EOF) { |
| memset(buf, 0, len); |
| status = APR_SUCCESS; |
| } |
| } |
| |
| return status; |
| } |
| |
| /* |
| * the following two routines will break if |
| * deletions aren't taken into account. (ndbm bug) |
| */ |
| APU_DECLARE(apr_status_t) apr_sdbm_firstkey(apr_sdbm_t *db, |
| apr_sdbm_datum_t *key) |
| { |
| apr_status_t status; |
| |
| if ((status = apr_sdbm_lock(db, APR_FLOCK_SHARED)) != APR_SUCCESS) |
| return status; |
| |
| /* |
| * start at page 0 |
| */ |
| if ((status = read_from(db->pagf, db->pagbuf, OFF_PAG(0), PBLKSIZ)) |
| == APR_SUCCESS) { |
| db->pagbno = 0; |
| db->blkptr = 0; |
| db->keyptr = 0; |
| status = getnext(key, db); |
| } |
| |
| (void) apr_sdbm_unlock(db); |
| |
| return status; |
| } |
| |
| APU_DECLARE(apr_status_t) apr_sdbm_nextkey(apr_sdbm_t *db, |
| apr_sdbm_datum_t *key) |
| { |
| apr_status_t status; |
| |
| if ((status = apr_sdbm_lock(db, APR_FLOCK_SHARED)) != APR_SUCCESS) |
| return status; |
| |
| status = getnext(key, db); |
| |
| (void) apr_sdbm_unlock(db); |
| |
| return status; |
| } |
| |
| /* |
| * all important binary tree traversal |
| */ |
| static apr_status_t getpage(apr_sdbm_t *db, long hash) |
| { |
| register int hbit; |
| register long dbit; |
| register long pagb; |
| apr_status_t status; |
| |
| dbit = 0; |
| hbit = 0; |
| while (dbit < db->maxbno && getdbit(db, dbit)) |
| dbit = 2 * dbit + ((hash & (1 << hbit++)) ? 2 : 1); |
| |
| debug(("dbit: %d...", dbit)); |
| |
| db->curbit = dbit; |
| db->hmask = masks[hbit]; |
| |
| pagb = hash & db->hmask; |
| /* |
| * see if the block we need is already in memory. |
| * note: this lookaside cache has about 10% hit rate. |
| */ |
| if (pagb != db->pagbno) { |
| /* |
| * note: here, we assume a "hole" is read as 0s. |
| * if not, must zero pagbuf first. |
| * ### joe: this assumption was surely never correct? but |
| * ### we make it so in read_from anyway. |
| */ |
| if ((status = read_from(db->pagf, db->pagbuf, OFF_PAG(pagb), PBLKSIZ)) |
| != APR_SUCCESS) |
| return status; |
| |
| if (!chkpage(db->pagbuf)) |
| return APR_ENOSPC; /* ### better error? */ |
| db->pagbno = pagb; |
| |
| debug(("pag read: %d\n", pagb)); |
| } |
| return APR_SUCCESS; |
| } |
| |
| static int getdbit(apr_sdbm_t *db, long dbit) |
| { |
| register long c; |
| register long dirb; |
| |
| c = dbit / BYTESIZ; |
| dirb = c / DBLKSIZ; |
| |
| if (dirb != db->dirbno) { |
| if (read_from(db->dirf, db->dirbuf, OFF_DIR(dirb), DBLKSIZ) |
| != APR_SUCCESS) |
| return 0; |
| |
| db->dirbno = dirb; |
| |
| debug(("dir read: %d\n", dirb)); |
| } |
| |
| return db->dirbuf[c % DBLKSIZ] & (1 << dbit % BYTESIZ); |
| } |
| |
| static apr_status_t setdbit(apr_sdbm_t *db, long dbit) |
| { |
| register long c; |
| register long dirb; |
| apr_status_t status; |
| apr_off_t off; |
| |
| c = dbit / BYTESIZ; |
| dirb = c / DBLKSIZ; |
| |
| if (dirb != db->dirbno) { |
| if ((status = read_from(db->dirf, db->dirbuf, OFF_DIR(dirb), DBLKSIZ)) |
| != APR_SUCCESS) |
| return status; |
| |
| db->dirbno = dirb; |
| |
| debug(("dir read: %d\n", dirb)); |
| } |
| |
| db->dirbuf[c % DBLKSIZ] |= (1 << dbit % BYTESIZ); |
| |
| if (dbit >= db->maxbno) |
| db->maxbno += DBLKSIZ * BYTESIZ; |
| |
| off = OFF_DIR(dirb); |
| if ((status = apr_file_seek(db->dirf, APR_SET, &off)) == APR_SUCCESS) |
| status = apr_file_write_full(db->dirf, db->dirbuf, DBLKSIZ, NULL); |
| |
| return status; |
| } |
| |
| /* |
| * getnext - get the next key in the page, and if done with |
| * the page, try the next page in sequence |
| */ |
| static apr_status_t getnext(apr_sdbm_datum_t *key, apr_sdbm_t *db) |
| { |
| apr_status_t status; |
| for (;;) { |
| db->keyptr++; |
| *key = getnkey(db->pagbuf, db->keyptr); |
| if (key->dptr != NULL) |
| return APR_SUCCESS; |
| /* |
| * we either run out, or there is nothing on this page.. |
| * try the next one... If we lost our position on the |
| * file, we will have to seek. |
| */ |
| db->keyptr = 0; |
| if (db->pagbno != db->blkptr++) { |
| apr_off_t off = OFF_PAG(db->blkptr); |
| if ((status = apr_file_seek(db->pagf, APR_SET, &off) |
| != APR_SUCCESS)) |
| return status; |
| } |
| |
| db->pagbno = db->blkptr; |
| /* ### EOF acceptable here too? */ |
| if ((status = apr_file_read_full(db->pagf, db->pagbuf, PBLKSIZ, NULL)) |
| != APR_SUCCESS) |
| return status; |
| if (!chkpage(db->pagbuf)) |
| return APR_EGENERAL; /* ### need better error */ |
| } |
| |
| /* NOTREACHED */ |
| } |
| |
| |
| APU_DECLARE(int) apr_sdbm_rdonly(apr_sdbm_t *db) |
| { |
| /* ### Should we return true if the first lock is a share lock, |
| * to reflect that apr_sdbm_store and apr_sdbm_delete will fail? |
| */ |
| return (db->flags & SDBM_RDONLY) != 0; |
| } |
| |
