/* * Copyright (c) 1999 Apple Computer, Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * The contents of this file constitute Original Code as defined in and * are subject to the Apple Public Source License Version 1.1 (the * "License"). You may not use this file except in compliance with the * License. Please obtain a copy of the License at * http://www.apple.com/publicsource and read it before using this file. * * This Original Code and all software distributed under the License are * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the * License for the specific language governing rights and limitations * under the License. * * @APPLE_LICENSE_HEADER_END@ */ /* * Copyright (c) 1990, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Mike Olson. * * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 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. */ /* * Implementation of btree access method for 4.4BSD. * * The design here was originally based on that of the btree access method * used in the Postgres database system at UC Berkeley. This implementation * is wholly independent of the Postgres code. */ #include <sys/param.h> #include <sys/stat.h> #include <errno.h> #include <fcntl.h> #include <limits.h> #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <db.h> #include "btree.h" static int byteorder __P((void)); static int nroot __P((BTREE *)); static int tmp __P((void)); /* * __BT_OPEN -- Open a btree. * * Creates and fills a DB struct, and calls the routine that actually * opens the btree. * * Parameters: * fname: filename (NULL for in-memory trees) * flags: open flag bits * mode: open permission bits * b: BTREEINFO pointer * * Returns: * NULL on failure, pointer to DB on success. * */ DB * __bt_open(fname, flags, mode, openinfo, dflags) const char *fname; int flags, mode, dflags; const BTREEINFO *openinfo; { struct stat sb; BTMETA m; BTREE *t; BTREEINFO b; DB *dbp; pgno_t ncache; ssize_t nr; int machine_lorder; t = NULL; /* * Intention is to make sure all of the user's selections are okay * here and then use them without checking. Can't be complete, since * we don't know the right page size, lorder or flags until the backing * file is opened. Also, the file's page size can cause the cachesize * to change. */ machine_lorder = byteorder(); if (openinfo) { b = *openinfo; /* Flags: R_DUP. */ if (b.flags & ~(R_DUP)) goto einval; /* * Page size must be indx_t aligned and >= MINPSIZE. Default * page size is set farther on, based on the underlying file * transfer size. */ if (b.psize && (b.psize < MINPSIZE || b.psize > MAX_PAGE_OFFSET + 1 || b.psize & sizeof(indx_t) - 1)) goto einval; /* Minimum number of keys per page; absolute minimum is 2. */ if (b.minkeypage) { if (b.minkeypage < 2) goto einval; } else b.minkeypage = DEFMINKEYPAGE; /* If no comparison, use default comparison and prefix. */ if (b.compare == NULL) { b.compare = __bt_defcmp; if (b.prefix == NULL) b.prefix = __bt_defpfx; } if (b.lorder == 0) b.lorder = machine_lorder; } else { b.compare = __bt_defcmp; b.cachesize = 0; b.flags = 0; b.lorder = machine_lorder; b.minkeypage = DEFMINKEYPAGE; b.prefix = __bt_defpfx; b.psize = 0; } /* Check for the ubiquitous PDP-11. */ if (b.lorder != BIG_ENDIAN && b.lorder != LITTLE_ENDIAN) goto einval; /* Allocate and initialize DB and BTREE structures. */ if ((t = (BTREE *)malloc(sizeof(BTREE))) == NULL) goto err; memset(t, 0, sizeof(BTREE)); t->bt_bcursor.pgno = P_INVALID; t->bt_fd = -1; /* Don't close unopened fd on error. */ t->bt_lorder = b.lorder; t->bt_order = NOT; t->bt_cmp = b.compare; t->bt_pfx = b.prefix; t->bt_rfd = -1; if ((t->bt_dbp = dbp = (DB *)malloc(sizeof(DB))) == NULL) goto err; t->bt_flags = 0; if (t->bt_lorder != machine_lorder) SET(t, B_NEEDSWAP); dbp->type = DB_BTREE; dbp->internal = t; dbp->close = __bt_close; dbp->del = __bt_delete; dbp->fd = __bt_fd; dbp->get = __bt_get; dbp->put = __bt_put; dbp->seq = __bt_seq; dbp->sync = __bt_sync; /* * If no file name was supplied, this is an in-memory btree and we * open a backing temporary file. Otherwise, it's a disk-based tree. */ if (fname) { switch(flags & O_ACCMODE) { case O_RDONLY: SET(t, B_RDONLY); break; case O_RDWR: break; case O_WRONLY: default: goto einval; } if ((t->bt_fd = open(fname, flags, mode)) < 0) goto err; } else { if ((flags & O_ACCMODE) != O_RDWR) goto einval; if ((t->bt_fd = tmp()) == -1) goto err; SET(t, B_INMEM); } if (fcntl(t->bt_fd, F_SETFD, 1) == -1) goto err; if (fstat(t->bt_fd, &sb)) goto err; if (sb.st_size) { nr = read(t->bt_fd, &m, sizeof(BTMETA)); if (nr < 0) goto err; if (nr != sizeof(BTMETA)) goto eftype; /* * Read in the meta-data. This can change the notion of what * the lorder, page size and flags are, and, when the page size * changes, the cachesize value can change too. If the user * specified the wrong byte order for an existing database, we * don't bother to return an error, we just clear the NEEDSWAP * bit. */ if (m.m_magic == BTREEMAGIC) CLR(t, B_NEEDSWAP); else { SET(t, B_NEEDSWAP); M_32_SWAP(m.m_magic); M_32_SWAP(m.m_version); M_32_SWAP(m.m_psize); M_32_SWAP(m.m_free); M_32_SWAP(m.m_nrecs); M_32_SWAP(m.m_flags); } if (m.m_magic != BTREEMAGIC || m.m_version != BTREEVERSION) goto eftype; if (m.m_psize < MINPSIZE || m.m_psize > MAX_PAGE_OFFSET + 1 || m.m_psize & sizeof(indx_t) - 1) goto eftype; if (m.m_flags & ~SAVEMETA) goto eftype; b.psize = m.m_psize; t->bt_flags |= m.m_flags; t->bt_free = m.m_free; t->bt_nrecs = m.m_nrecs; } else { /* * Set the page size to the best value for I/O to this file. * Don't overflow the page offset type. */ if (b.psize == 0) { b.psize = sb.st_blksize; if (b.psize < MINPSIZE) b.psize = MINPSIZE; if (b.psize > MAX_PAGE_OFFSET + 1) b.psize = MAX_PAGE_OFFSET + 1; } /* Set flag if duplicates permitted. */ if (!(b.flags & R_DUP)) SET(t, B_NODUPS); t->bt_free = P_INVALID; t->bt_nrecs = 0; SET(t, B_METADIRTY); } t->bt_psize = b.psize; /* Set the cache size; must be a multiple of the page size. */ if (b.cachesize && b.cachesize & b.psize - 1) b.cachesize += (~b.cachesize & b.psize - 1) + 1; if (b.cachesize < b.psize * MINCACHE) b.cachesize = b.psize * MINCACHE; /* Calculate number of pages to cache. */ ncache = (b.cachesize + t->bt_psize - 1) / t->bt_psize; /* * The btree data structure requires that at least two keys can fit on * a page, but other than that there's no fixed requirement. The user * specified a minimum number per page, and we translated that into the * number of bytes a key/data pair can use before being placed on an * overflow page. This calculation includes the page header, the size * of the index referencing the leaf item and the size of the leaf item * structure. Also, don't let the user specify a minkeypage such that * a key/data pair won't fit even if both key and data are on overflow * pages. */ t->bt_ovflsize = (t->bt_psize - BTDATAOFF) / b.minkeypage - (sizeof(indx_t) + NBLEAFDBT(0, 0)); if (t->bt_ovflsize < NBLEAFDBT(NOVFLSIZE, NOVFLSIZE) + sizeof(indx_t)) t->bt_ovflsize = NBLEAFDBT(NOVFLSIZE, NOVFLSIZE) + sizeof(indx_t); /* Initialize the buffer pool. */ if ((t->bt_mp = mpool_open(NULL, t->bt_fd, t->bt_psize, ncache)) == NULL) goto err; if (!ISSET(t, B_INMEM)) mpool_filter(t->bt_mp, __bt_pgin, __bt_pgout, t); /* Create a root page if new tree. */ if (nroot(t) == RET_ERROR) goto err; /* Global flags. */ if (dflags & DB_LOCK) SET(t, B_DB_LOCK); if (dflags & DB_SHMEM) SET(t, B_DB_SHMEM); if (dflags & DB_TXN) SET(t, B_DB_TXN); return (dbp); einval: errno = EINVAL; goto err; eftype: errno = EFTYPE; goto err; err: if (t) { if (t->bt_dbp) free(t->bt_dbp); if (t->bt_fd != -1) (void)close(t->bt_fd); free(t); } return (NULL); } /* * NROOT -- Create the root of a new tree. * * Parameters: * t: tree * * Returns: * RET_ERROR, RET_SUCCESS */ static int nroot(t) BTREE *t; { PAGE *meta, *root; pgno_t npg; if ((meta = mpool_get(t->bt_mp, 0, 0)) != NULL) { mpool_put(t->bt_mp, meta, 0); return (RET_SUCCESS); } if (errno != EINVAL) return (RET_ERROR); if ((meta = mpool_new(t->bt_mp, &npg)) == NULL) return (RET_ERROR); if ((root = mpool_new(t->bt_mp, &npg)) == NULL) return (RET_ERROR); if (npg != P_ROOT) return (RET_ERROR); root->pgno = npg; root->prevpg = root->nextpg = P_INVALID; root->lower = BTDATAOFF; root->upper = t->bt_psize; root->flags = P_BLEAF; memset(meta, 0, t->bt_psize); mpool_put(t->bt_mp, meta, MPOOL_DIRTY); mpool_put(t->bt_mp, root, MPOOL_DIRTY); return (RET_SUCCESS); } static int tmp() { sigset_t set, oset; int fd; char *envtmp; char path[MAXPATHLEN]; envtmp = getenv("TMPDIR"); (void)snprintf(path, sizeof(path), "%s/bt.XXXXXX", envtmp ? envtmp : "/tmp"); (void)sigfillset(&set); (void)sigprocmask(SIG_BLOCK, &set, &oset); if ((fd = mkstemp(path)) != -1) (void)unlink(path); (void)sigprocmask(SIG_SETMASK, &oset, NULL); return(fd); } static int byteorder() { u_int32_t x; u_char *p; x = 0x01020304; p = (u_char *)&x; switch (*p) { case 1: return (BIG_ENDIAN); case 4: return (LITTLE_ENDIAN); default: return (0); } } int __bt_fd(dbp) const DB *dbp; { BTREE *t; t = dbp->internal; /* Toss any page pinned across calls. */ if (t->bt_pinned != NULL) { mpool_put(t->bt_mp, t->bt_pinned, 0); t->bt_pinned = NULL; } /* In-memory database can't have a file descriptor. */ if (ISSET(t, B_INMEM)) { errno = ENOENT; return (-1); } return (t->bt_fd); }