bt_open.c revision 190344
1262569Simp/*- 2262569Simp * Copyright (c) 1990, 1993, 1994 3262569Simp * The Regents of the University of California. All rights reserved. 4262569Simp * 5262569Simp * This code is derived from software contributed to Berkeley by 6262569Simp * Mike Olson. 7262569Simp * 8262569Simp * Redistribution and use in source and binary forms, with or without 9262569Simp * modification, are permitted provided that the following conditions 10262569Simp * are met: 11270864Simp * 1. Redistributions of source code must retain the above copyright 12270864Simp * notice, this list of conditions and the following disclaimer. 13262569Simp * 2. Redistributions in binary form must reproduce the above copyright 14262569Simp * notice, this list of conditions and the following disclaimer in the 15262569Simp * documentation and/or other materials provided with the distribution. 16262569Simp * 4. Neither the name of the University nor the names of its contributors 17262569Simp * may be used to endorse or promote products derived from this software 18262569Simp * without specific prior written permission. 19262569Simp * 20262569Simp * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21262569Simp * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22262569Simp * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23279385Simp * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24279385Simp * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25279385Simp * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26279385Simp * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27279385Simp * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28279385Simp * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29279385Simp * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30270864Simp * SUCH DAMAGE. 31270864Simp */ 32270864Simp 33270864Simp#if defined(LIBC_SCCS) && !defined(lint) 34270864Simpstatic char sccsid[] = "@(#)bt_open.c 8.10 (Berkeley) 8/17/94"; 35270864Simp#endif /* LIBC_SCCS and not lint */ 36270864Simp#include <sys/cdefs.h> 37270864Simp__FBSDID("$FreeBSD: head/lib/libc/db/btree/bt_open.c 190344 2009-03-23 23:43:07Z delphij $"); 38270864Simp 39270864Simp/* 40270864Simp * Implementation of btree access method for 4.4BSD. 41270864Simp * 42262569Simp * The design here was originally based on that of the btree access method 43262569Simp * used in the Postgres database system at UC Berkeley. This implementation 44270864Simp * is wholly independent of the Postgres code. 45270864Simp */ 46262569Simp 47270864Simp#include "namespace.h" 48262569Simp#include <sys/param.h> 49270864Simp#include <sys/stat.h> 50262569Simp 51262569Simp#include <errno.h> 52262569Simp#include <fcntl.h> 53262569Simp#include <limits.h> 54262569Simp#include <signal.h> 55295436Sandrew#include <stdio.h> 56262569Simp#include <stdlib.h> 57262569Simp#include <string.h> 58270864Simp#include <unistd.h> 59262569Simp#include "un-namespace.h" 60270864Simp 61262569Simp#include <db.h> 62262569Simp#include "btree.h" 63262569Simp 64262569Simp#ifdef DEBUG 65262569Simp#undef MINPSIZE 66295436Sandrew#define MINPSIZE 128 67262569Simp#endif 68270864Simp 69270864Simpstatic int byteorder(void); 70270864Simpstatic int nroot(BTREE *); 71270864Simpstatic int tmp(void); 72270864Simp 73270864Simp/* 74270864Simp * __BT_OPEN -- Open a btree. 75270864Simp * 76270864Simp * Creates and fills a DB struct, and calls the routine that actually 77270864Simp * opens the btree. 78270864Simp * 79270864Simp * Parameters: 80270864Simp * fname: filename (NULL for in-memory trees) 81270864Simp * flags: open flag bits 82270864Simp * mode: open permission bits 83270864Simp * b: BTREEINFO pointer 84270864Simp * 85270864Simp * Returns: 86279385Simp * NULL on failure, pointer to DB on success. 87279385Simp * 88279385Simp */ 89279385SimpDB * 90279385Simp__bt_open(const char *fname, int flags, int mode, const BTREEINFO *openinfo, int dflags) 91279385Simp{ 92279385Simp struct stat sb; 93279385Simp BTMETA m; 94262569Simp BTREE *t; 95270864Simp BTREEINFO b; 96270864Simp DB *dbp; 97270864Simp pgno_t ncache; 98270864Simp ssize_t nr; 99270864Simp int machine_lorder, saved_errno; 100270864Simp 101270864Simp t = NULL; 102270864Simp 103270864Simp /* 104270864Simp * Intention is to make sure all of the user's selections are okay 105270864Simp * here and then use them without checking. Can't be complete, since 106270864Simp * we don't know the right page size, lorder or flags until the backing 107270864Simp * file is opened. Also, the file's page size can cause the cachesize 108270864Simp * to change. 109270864Simp */ 110270864Simp machine_lorder = byteorder(); 111262569Simp if (openinfo) { 112262569Simp b = *openinfo; 113270864Simp 114270864Simp /* Flags: R_DUP. */ 115270864Simp if (b.flags & ~(R_DUP)) 116270864Simp goto einval; 117270864Simp 118270864Simp /* 119262569Simp * Page size must be indx_t aligned and >= MINPSIZE. Default 120262569Simp * page size is set farther on, based on the underlying file 121262569Simp * transfer size. 122262569Simp */ 123270864Simp if (b.psize && 124262569Simp (b.psize < MINPSIZE || b.psize > MAX_PAGE_OFFSET + 1 || 125262569Simp b.psize & (sizeof(indx_t) - 1) )) 126262569Simp goto einval; 127262569Simp 128262569Simp /* Minimum number of keys per page; absolute minimum is 2. */ 129295436Sandrew if (b.minkeypage) { 130262569Simp if (b.minkeypage < 2) 131262569Simp goto einval; 132262569Simp } else 133262569Simp b.minkeypage = DEFMINKEYPAGE; 134262569Simp 135262569Simp /* If no comparison, use default comparison and prefix. */ 136270864Simp if (b.compare == NULL) { 137270864Simp b.compare = __bt_defcmp; 138270864Simp if (b.prefix == NULL) 139262569Simp b.prefix = __bt_defpfx; 140262569Simp } 141262569Simp 142262569Simp if (b.lorder == 0) 143270864Simp b.lorder = machine_lorder; 144270864Simp } else { 145270864Simp b.compare = __bt_defcmp; 146270864Simp b.cachesize = 0; 147270864Simp b.flags = 0; 148270864Simp b.lorder = machine_lorder; 149270864Simp b.minkeypage = DEFMINKEYPAGE; 150270864Simp b.prefix = __bt_defpfx; 151270864Simp b.psize = 0; 152270864Simp } 153270864Simp 154270864Simp /* Check for the ubiquitous PDP-11. */ 155270864Simp if (b.lorder != BIG_ENDIAN && b.lorder != LITTLE_ENDIAN) 156270864Simp goto einval; 157270864Simp 158270864Simp /* Allocate and initialize DB and BTREE structures. */ 159270864Simp if ((t = (BTREE *)malloc(sizeof(BTREE))) == NULL) 160270864Simp goto err; 161270864Simp memset(t, 0, sizeof(BTREE)); 162270864Simp t->bt_fd = -1; /* Don't close unopened fd on error. */ 163270864Simp t->bt_lorder = b.lorder; 164270864Simp t->bt_order = NOT; 165270864Simp t->bt_cmp = b.compare; 166270864Simp t->bt_pfx = b.prefix; 167270864Simp t->bt_rfd = -1; 168270864Simp 169270864Simp if ((t->bt_dbp = dbp = (DB *)malloc(sizeof(DB))) == NULL) 170270864Simp goto err; 171270864Simp memset(t->bt_dbp, 0, sizeof(DB)); 172270864Simp if (t->bt_lorder != machine_lorder) 173270864Simp F_SET(t, B_NEEDSWAP); 174270864Simp 175270864Simp dbp->type = DB_BTREE; 176270864Simp dbp->internal = t; 177270864Simp dbp->close = __bt_close; 178270864Simp dbp->del = __bt_delete; 179270864Simp dbp->fd = __bt_fd; 180270864Simp dbp->get = __bt_get; 181270864Simp dbp->put = __bt_put; 182270864Simp dbp->seq = __bt_seq; 183270864Simp dbp->sync = __bt_sync; 184270864Simp 185270864Simp /* 186270864Simp * If no file name was supplied, this is an in-memory btree and we 187270864Simp * open a backing temporary file. Otherwise, it's a disk-based tree. 188270864Simp */ 189270864Simp if (fname) { 190270864Simp switch (flags & O_ACCMODE) { 191270864Simp case O_RDONLY: 192270864Simp F_SET(t, B_RDONLY); 193270864Simp break; 194270864Simp case O_RDWR: 195270864Simp break; 196270864Simp case O_WRONLY: 197270864Simp default: 198270864Simp goto einval; 199270864Simp } 200270864Simp 201270864Simp if ((t->bt_fd = _open(fname, flags, mode)) < 0) 202270864Simp goto err; 203270864Simp 204270864Simp } else { 205270864Simp if ((flags & O_ACCMODE) != O_RDWR) 206270864Simp goto einval; 207270864Simp if ((t->bt_fd = tmp()) == -1) 208270864Simp goto err; 209270864Simp F_SET(t, B_INMEM); 210270864Simp } 211270864Simp 212270864Simp if (_fcntl(t->bt_fd, F_SETFD, 1) == -1) 213270864Simp goto err; 214270864Simp 215270864Simp if (_fstat(t->bt_fd, &sb)) 216270864Simp goto err; 217270864Simp if (sb.st_size) { 218270864Simp if ((nr = _read(t->bt_fd, &m, sizeof(BTMETA))) < 0) 219270864Simp goto err; 220270864Simp if (nr != sizeof(BTMETA)) 221270864Simp goto eftype; 222270864Simp 223270864Simp /* 224270864Simp * Read in the meta-data. This can change the notion of what 225270864Simp * the lorder, page size and flags are, and, when the page size 226270864Simp * changes, the cachesize value can change too. If the user 227270864Simp * specified the wrong byte order for an existing database, we 228270864Simp * don't bother to return an error, we just clear the NEEDSWAP 229270864Simp * bit. 230270864Simp */ 231270864Simp if (m.magic == BTREEMAGIC) 232270864Simp F_CLR(t, B_NEEDSWAP); 233270864Simp else { 234270864Simp F_SET(t, B_NEEDSWAP); 235270864Simp M_32_SWAP(m.magic); 236270864Simp M_32_SWAP(m.version); 237270864Simp M_32_SWAP(m.psize); 238270864Simp M_32_SWAP(m.free); 239270864Simp M_32_SWAP(m.nrecs); 240270864Simp M_32_SWAP(m.flags); 241270864Simp } 242270864Simp if (m.magic != BTREEMAGIC || m.version != BTREEVERSION) 243270864Simp goto eftype; 244270864Simp if (m.psize < MINPSIZE || m.psize > MAX_PAGE_OFFSET + 1 || 245270864Simp m.psize & (sizeof(indx_t) - 1) ) 246270864Simp goto eftype; 247270864Simp if (m.flags & ~SAVEMETA) 248270864Simp goto eftype; 249270864Simp b.psize = m.psize; 250270864Simp F_SET(t, m.flags); 251270864Simp t->bt_free = m.free; 252270864Simp t->bt_nrecs = m.nrecs; 253270864Simp } else { 254270864Simp /* 255270864Simp * Set the page size to the best value for I/O to this file. 256270864Simp * Don't overflow the page offset type. 257270864Simp */ 258270864Simp if (b.psize == 0) { 259270864Simp b.psize = sb.st_blksize; 260270864Simp if (b.psize < MINPSIZE) 261270864Simp b.psize = MINPSIZE; 262270864Simp if (b.psize > MAX_PAGE_OFFSET + 1) 263270864Simp b.psize = MAX_PAGE_OFFSET + 1; 264270864Simp } 265270864Simp 266270864Simp /* Set flag if duplicates permitted. */ 267270864Simp if (!(b.flags & R_DUP)) 268270864Simp F_SET(t, B_NODUPS); 269270864Simp 270270864Simp t->bt_free = P_INVALID; 271262569Simp t->bt_nrecs = 0; 272262569Simp F_SET(t, B_METADIRTY); 273262569Simp } 274262569Simp 275270864Simp t->bt_psize = b.psize; 276262569Simp 277262569Simp /* Set the cache size; must be a multiple of the page size. */ 278262569Simp if (b.cachesize && b.cachesize & (b.psize - 1) ) 279262569Simp b.cachesize += (~b.cachesize & (b.psize - 1) ) + 1; 280262569Simp if (b.cachesize < b.psize * MINCACHE) 281262569Simp b.cachesize = b.psize * MINCACHE; 282262569Simp 283262569Simp /* Calculate number of pages to cache. */ 284262569Simp ncache = (b.cachesize + t->bt_psize - 1) / t->bt_psize; 285270864Simp 286262569Simp /* 287262569Simp * The btree data structure requires that at least two keys can fit on 288270864Simp * a page, but other than that there's no fixed requirement. The user 289270864Simp * specified a minimum number per page, and we translated that into the 290270864Simp * number of bytes a key/data pair can use before being placed on an 291270864Simp * overflow page. This calculation includes the page header, the size 292270864Simp * of the index referencing the leaf item and the size of the leaf item 293270864Simp * structure. Also, don't let the user specify a minkeypage such that 294270864Simp * a key/data pair won't fit even if both key and data are on overflow 295270864Simp * pages. 296270864Simp */ 297270864Simp t->bt_ovflsize = (t->bt_psize - BTDATAOFF) / b.minkeypage - 298270864Simp (sizeof(indx_t) + NBLEAFDBT(0, 0)); 299270864Simp if (t->bt_ovflsize < NBLEAFDBT(NOVFLSIZE, NOVFLSIZE) + sizeof(indx_t)) 300270864Simp t->bt_ovflsize = 301270864Simp NBLEAFDBT(NOVFLSIZE, NOVFLSIZE) + sizeof(indx_t); 302270864Simp 303270864Simp /* Initialize the buffer pool. */ 304270864Simp if ((t->bt_mp = 305270864Simp mpool_open(NULL, t->bt_fd, t->bt_psize, ncache)) == NULL) 306270864Simp goto err; 307270864Simp if (!F_ISSET(t, B_INMEM)) 308270864Simp mpool_filter(t->bt_mp, __bt_pgin, __bt_pgout, t); 309270864Simp 310270864Simp /* Create a root page if new tree. */ 311270864Simp if (nroot(t) == RET_ERROR) 312270864Simp goto err; 313270864Simp 314270864Simp /* Global flags. */ 315270864Simp if (dflags & DB_LOCK) 316270864Simp F_SET(t, B_DB_LOCK); 317270864Simp if (dflags & DB_SHMEM) 318270864Simp F_SET(t, B_DB_SHMEM); 319270864Simp if (dflags & DB_TXN) 320270864Simp F_SET(t, B_DB_TXN); 321270864Simp 322270864Simp return (dbp); 323270864Simp 324270864Simpeinval: errno = EINVAL; 325270864Simp goto err; 326270864Simp 327270864Simpeftype: errno = EFTYPE; 328270864Simp goto err; 329270864Simp 330270864Simperr: saved_errno = errno; 331270864Simp if (t) { 332270864Simp if (t->bt_dbp) 333270864Simp free(t->bt_dbp); 334270864Simp if (t->bt_fd != -1) 335270864Simp (void)_close(t->bt_fd); 336270864Simp free(t); 337270864Simp } 338270864Simp errno = saved_errno; 339270864Simp return (NULL); 340270864Simp} 341270864Simp 342270864Simp/* 343270864Simp * NROOT -- Create the root of a new tree. 344270864Simp * 345270864Simp * Parameters: 346270864Simp * t: tree 347270864Simp * 348270864Simp * Returns: 349270864Simp * RET_ERROR, RET_SUCCESS 350270864Simp */ 351270864Simpstatic int 352270864Simpnroot(BTREE *t) 353270864Simp{ 354270864Simp PAGE *meta, *root; 355270864Simp pgno_t npg; 356270864Simp 357270864Simp if ((meta = mpool_get(t->bt_mp, 0, 0)) != NULL) { 358270864Simp mpool_put(t->bt_mp, meta, 0); 359270864Simp return (RET_SUCCESS); 360279385Simp } 361279385Simp if (errno != EINVAL) /* It's OK to not exist. */ 362279385Simp return (RET_ERROR); 363279385Simp errno = 0; 364279385Simp 365279385Simp if ((meta = mpool_new(t->bt_mp, &npg)) == NULL) 366279385Simp return (RET_ERROR); 367279385Simp 368279385Simp if ((root = mpool_new(t->bt_mp, &npg)) == NULL) 369279385Simp return (RET_ERROR); 370279385Simp 371279385Simp if (npg != P_ROOT) 372279385Simp return (RET_ERROR); 373279385Simp root->pgno = npg; 374279385Simp root->prevpg = root->nextpg = P_INVALID; 375279385Simp root->lower = BTDATAOFF; 376279385Simp root->upper = t->bt_psize; 377279385Simp root->flags = P_BLEAF; 378279385Simp memset(meta, 0, t->bt_psize); 379279385Simp mpool_put(t->bt_mp, meta, MPOOL_DIRTY); 380279385Simp mpool_put(t->bt_mp, root, MPOOL_DIRTY); 381279385Simp return (RET_SUCCESS); 382279385Simp} 383279385Simp 384279385Simpstatic int 385279385Simptmp(void) 386279385Simp{ 387279385Simp sigset_t set, oset; 388279385Simp int fd; 389279385Simp char *envtmp = NULL; 390279385Simp char path[MAXPATHLEN]; 391279385Simp 392279385Simp if (issetugid() == 0) 393279385Simp envtmp = getenv("TMPDIR"); 394279385Simp (void)snprintf(path, 395279385Simp sizeof(path), "%s/bt.XXXXXXXXXX", envtmp ? envtmp : "/tmp"); 396279385Simp 397279385Simp (void)sigfillset(&set); 398279385Simp (void)_sigprocmask(SIG_BLOCK, &set, &oset); 399279385Simp if ((fd = mkstemp(path)) != -1) 400279385Simp (void)unlink(path); 401279385Simp (void)_sigprocmask(SIG_SETMASK, &oset, NULL); 402279385Simp return(fd); 403279385Simp} 404279385Simp 405270864Simpstatic int 406270864Simpbyteorder(void) 407270864Simp{ 408270864Simp u_int32_t x; 409270864Simp u_char *p; 410270864Simp 411270864Simp x = 0x01020304; 412270864Simp p = (u_char *)&x; 413270864Simp switch (*p) { 414270864Simp case 1: 415270864Simp return (BIG_ENDIAN); 416270864Simp case 4: 417270864Simp return (LITTLE_ENDIAN); 418270864Simp default: 419270864Simp return (0); 420270864Simp } 421270864Simp} 422270864Simp 423270864Simpint 424270864Simp__bt_fd(const DB *dbp) 425270864Simp{ 426270864Simp BTREE *t; 427270864Simp 428270864Simp t = dbp->internal; 429270864Simp 430270864Simp /* Toss any page pinned across calls. */ 431270864Simp if (t->bt_pinned != NULL) { 432270864Simp mpool_put(t->bt_mp, t->bt_pinned, 0); 433270864Simp t->bt_pinned = NULL; 434270864Simp } 435270864Simp 436270864Simp /* In-memory database can't have a file descriptor. */ 437270864Simp if (F_ISSET(t, B_INMEM)) { 438270864Simp errno = ENOENT; 439270864Simp return (-1); 440270864Simp } 441270864Simp return (t->bt_fd); 442270864Simp} 443270864Simp