1/*- 2 * Copyright (c) 1990, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Mike Olson. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33#if defined(LIBC_SCCS) && !defined(lint) 34static char sccsid[] = "@(#)bt_open.c 8.10 (Berkeley) 8/17/94"; 35#endif /* LIBC_SCCS and not lint */ 36#include <sys/cdefs.h> 37__FBSDID("$FreeBSD$"); 38 39/* 40 * Implementation of btree access method for 4.4BSD. 41 * 42 * The design here was originally based on that of the btree access method 43 * used in the Postgres database system at UC Berkeley. This implementation 44 * is wholly independent of the Postgres code. 45 */ 46 47#include "namespace.h" 48#include <sys/param.h> 49#include <sys/stat.h> 50 51#include <errno.h> 52#include <fcntl.h> 53#include <limits.h> 54#include <signal.h> 55#include <stdio.h> 56#include <stdlib.h> 57#include <string.h> 58#include <unistd.h> 59#include "un-namespace.h" 60 61#include <db.h> 62#include "btree.h" 63 64#ifdef DEBUG 65#undef MINPSIZE 66#define MINPSIZE 128 67#endif 68 69static int byteorder(void); 70static int nroot(BTREE *); 71static int tmp(void); 72 73/* 74 * __BT_OPEN -- Open a btree. 75 * 76 * Creates and fills a DB struct, and calls the routine that actually 77 * opens the btree. 78 * 79 * Parameters: 80 * fname: filename (NULL for in-memory trees) 81 * flags: open flag bits 82 * mode: open permission bits 83 * b: BTREEINFO pointer 84 * 85 * Returns: 86 * NULL on failure, pointer to DB on success. 87 * 88 */ 89DB * 90__bt_open(const char *fname, int flags, int mode, const BTREEINFO *openinfo, int dflags) 91{ 92 struct stat sb; 93 BTMETA m; 94 BTREE *t; 95 BTREEINFO b; 96 DB *dbp; 97 pgno_t ncache; 98 ssize_t nr; 99 int machine_lorder, saved_errno; 100 101 t = NULL; 102 103 /* 104 * Intention is to make sure all of the user's selections are okay 105 * here and then use them without checking. Can't be complete, since 106 * we don't know the right page size, lorder or flags until the backing 107 * file is opened. Also, the file's page size can cause the cachesize 108 * to change. 109 */ 110 machine_lorder = byteorder(); 111 if (openinfo) { 112 b = *openinfo; 113 114 /* Flags: R_DUP. */ 115 if (b.flags & ~(R_DUP)) 116 goto einval; 117 118 /* 119 * Page size must be indx_t aligned and >= MINPSIZE. Default 120 * page size is set farther on, based on the underlying file 121 * transfer size. 122 */ 123 if (b.psize && 124 (b.psize < MINPSIZE || b.psize > MAX_PAGE_OFFSET + 1 || 125 b.psize & (sizeof(indx_t) - 1) )) 126 goto einval; 127 128 /* Minimum number of keys per page; absolute minimum is 2. */ 129 if (b.minkeypage) { 130 if (b.minkeypage < 2) 131 goto einval; 132 } else 133 b.minkeypage = DEFMINKEYPAGE; 134 135 /* If no comparison, use default comparison and prefix. */ 136 if (b.compare == NULL) { 137 b.compare = __bt_defcmp; 138 if (b.prefix == NULL) 139 b.prefix = __bt_defpfx; 140 } 141 142 if (b.lorder == 0) 143 b.lorder = machine_lorder; 144 } else { 145 b.compare = __bt_defcmp; 146 b.cachesize = 0; 147 b.flags = 0; 148 b.lorder = machine_lorder; 149 b.minkeypage = DEFMINKEYPAGE; 150 b.prefix = __bt_defpfx; 151 b.psize = 0; 152 } 153 154 /* Check for the ubiquitous PDP-11. */ 155 if (b.lorder != BIG_ENDIAN && b.lorder != LITTLE_ENDIAN) 156 goto einval; 157 158 /* Allocate and initialize DB and BTREE structures. */ 159 if ((t = (BTREE *)calloc(1, sizeof(BTREE))) == NULL) 160 goto err; 161 t->bt_fd = -1; /* Don't close unopened fd on error. */ 162 t->bt_lorder = b.lorder; 163 t->bt_order = NOT; 164 t->bt_cmp = b.compare; 165 t->bt_pfx = b.prefix; 166 t->bt_rfd = -1; 167 168 if ((t->bt_dbp = dbp = (DB *)calloc(1, sizeof(DB))) == NULL) 169 goto err; 170 if (t->bt_lorder != machine_lorder) 171 F_SET(t, B_NEEDSWAP); 172 173 dbp->type = DB_BTREE; 174 dbp->internal = t; 175 dbp->close = __bt_close; 176 dbp->del = __bt_delete; 177 dbp->fd = __bt_fd; 178 dbp->get = __bt_get; 179 dbp->put = __bt_put; 180 dbp->seq = __bt_seq; 181 dbp->sync = __bt_sync; 182 183 /* 184 * If no file name was supplied, this is an in-memory btree and we 185 * open a backing temporary file. Otherwise, it's a disk-based tree. 186 */ 187 if (fname) { 188 switch (flags & O_ACCMODE) { 189 case O_RDONLY: 190 F_SET(t, B_RDONLY); 191 break; 192 case O_RDWR: 193 break; 194 case O_WRONLY: 195 default: 196 goto einval; 197 } 198 199 if ((t->bt_fd = _open(fname, flags | O_CLOEXEC, mode)) < 0) 200 goto err; 201 202 } else { 203 if ((flags & O_ACCMODE) != O_RDWR) 204 goto einval; 205 if ((t->bt_fd = tmp()) == -1) 206 goto err; 207 F_SET(t, B_INMEM); 208 } 209 210 if (_fstat(t->bt_fd, &sb)) 211 goto err; 212 if (sb.st_size) { 213 if ((nr = _read(t->bt_fd, &m, sizeof(BTMETA))) < 0) 214 goto err; 215 if (nr != sizeof(BTMETA)) 216 goto eftype; 217 218 /* 219 * Read in the meta-data. This can change the notion of what 220 * the lorder, page size and flags are, and, when the page size 221 * changes, the cachesize value can change too. If the user 222 * specified the wrong byte order for an existing database, we 223 * don't bother to return an error, we just clear the NEEDSWAP 224 * bit. 225 */ 226 if (m.magic == BTREEMAGIC) 227 F_CLR(t, B_NEEDSWAP); 228 else { 229 F_SET(t, B_NEEDSWAP); 230 M_32_SWAP(m.magic); 231 M_32_SWAP(m.version); 232 M_32_SWAP(m.psize); 233 M_32_SWAP(m.free); 234 M_32_SWAP(m.nrecs); 235 M_32_SWAP(m.flags); 236 } 237 if (m.magic != BTREEMAGIC || m.version != BTREEVERSION) 238 goto eftype; 239 if (m.psize < MINPSIZE || m.psize > MAX_PAGE_OFFSET + 1 || 240 m.psize & (sizeof(indx_t) - 1) ) 241 goto eftype; 242 if (m.flags & ~SAVEMETA) 243 goto eftype; 244 b.psize = m.psize; 245 F_SET(t, m.flags); 246 t->bt_free = m.free; 247 t->bt_nrecs = m.nrecs; 248 } else { 249 /* 250 * Set the page size to the best value for I/O to this file. 251 * Don't overflow the page offset type. 252 */ 253 if (b.psize == 0) { 254 b.psize = sb.st_blksize; 255 if (b.psize < MINPSIZE) 256 b.psize = MINPSIZE; 257 if (b.psize > MAX_PAGE_OFFSET + 1) 258 b.psize = MAX_PAGE_OFFSET + 1; 259 } 260 261 /* Set flag if duplicates permitted. */ 262 if (!(b.flags & R_DUP)) 263 F_SET(t, B_NODUPS); 264 265 t->bt_free = P_INVALID; 266 t->bt_nrecs = 0; 267 F_SET(t, B_METADIRTY); 268 } 269 270 t->bt_psize = b.psize; 271 272 /* Set the cache size; must be a multiple of the page size. */ 273 if (b.cachesize && b.cachesize & (b.psize - 1) ) 274 b.cachesize += (~b.cachesize & (b.psize - 1) ) + 1; 275 if (b.cachesize < b.psize * MINCACHE) 276 b.cachesize = b.psize * MINCACHE; 277 278 /* Calculate number of pages to cache. */ 279 ncache = (b.cachesize + t->bt_psize - 1) / t->bt_psize; 280 281 /* 282 * The btree data structure requires that at least two keys can fit on 283 * a page, but other than that there's no fixed requirement. The user 284 * specified a minimum number per page, and we translated that into the 285 * number of bytes a key/data pair can use before being placed on an 286 * overflow page. This calculation includes the page header, the size 287 * of the index referencing the leaf item and the size of the leaf item 288 * structure. Also, don't let the user specify a minkeypage such that 289 * a key/data pair won't fit even if both key and data are on overflow 290 * pages. 291 */ 292 t->bt_ovflsize = (t->bt_psize - BTDATAOFF) / b.minkeypage - 293 (sizeof(indx_t) + NBLEAFDBT(0, 0)); 294 if (t->bt_ovflsize < NBLEAFDBT(NOVFLSIZE, NOVFLSIZE) + sizeof(indx_t)) 295 t->bt_ovflsize = 296 NBLEAFDBT(NOVFLSIZE, NOVFLSIZE) + sizeof(indx_t); 297 298 /* Initialize the buffer pool. */ 299 if ((t->bt_mp = 300 mpool_open(NULL, t->bt_fd, t->bt_psize, ncache)) == NULL) 301 goto err; 302 if (!F_ISSET(t, B_INMEM)) 303 mpool_filter(t->bt_mp, __bt_pgin, __bt_pgout, t); 304 305 /* Create a root page if new tree. */ 306 if (nroot(t) == RET_ERROR) 307 goto err; 308 309 /* Global flags. */ 310 if (dflags & DB_LOCK) 311 F_SET(t, B_DB_LOCK); 312 if (dflags & DB_SHMEM) 313 F_SET(t, B_DB_SHMEM); 314 if (dflags & DB_TXN) 315 F_SET(t, B_DB_TXN); 316 317 return (dbp); 318 319einval: errno = EINVAL; 320 goto err; 321 322eftype: errno = EFTYPE; 323 goto err; 324 325err: saved_errno = errno; 326 if (t) { 327 if (t->bt_dbp) 328 free(t->bt_dbp); 329 if (t->bt_fd != -1) 330 (void)_close(t->bt_fd); 331 free(t); 332 } 333 errno = saved_errno; 334 return (NULL); 335} 336 337/* 338 * NROOT -- Create the root of a new tree. 339 * 340 * Parameters: 341 * t: tree 342 * 343 * Returns: 344 * RET_ERROR, RET_SUCCESS 345 */ 346static int 347nroot(BTREE *t) 348{ 349 PAGE *meta, *root; 350 pgno_t npg; 351 352 if ((root = mpool_get(t->bt_mp, 1, 0)) != NULL) { 353 if (root->lower == 0 && 354 root->pgno == 0 && 355 root->linp[0] == 0) { 356 mpool_delete(t->bt_mp, root); 357 errno = EINVAL; 358 } else { 359 mpool_put(t->bt_mp, root, 0); 360 return (RET_SUCCESS); 361 } 362 } 363 if (errno != EINVAL) /* It's OK to not exist. */ 364 return (RET_ERROR); 365 errno = 0; 366 367 if ((meta = mpool_new(t->bt_mp, &npg, MPOOL_PAGE_NEXT)) == NULL) 368 return (RET_ERROR); 369 370 if ((root = mpool_new(t->bt_mp, &npg, MPOOL_PAGE_NEXT)) == NULL) 371 return (RET_ERROR); 372 373 if (npg != P_ROOT) 374 return (RET_ERROR); 375 root->pgno = npg; 376 root->prevpg = root->nextpg = P_INVALID; 377 root->lower = BTDATAOFF; 378 root->upper = t->bt_psize; 379 root->flags = P_BLEAF; 380 memset(meta, 0, t->bt_psize); 381 mpool_put(t->bt_mp, meta, MPOOL_DIRTY); 382 mpool_put(t->bt_mp, root, MPOOL_DIRTY); 383 return (RET_SUCCESS); 384} 385 386static int 387tmp(void) 388{ 389 sigset_t set, oset; 390 int fd, len; 391 char *envtmp = NULL; 392 char path[MAXPATHLEN]; 393 394 if (issetugid() == 0) 395 envtmp = getenv("TMPDIR"); 396 len = snprintf(path, 397 sizeof(path), "%s/bt.XXXXXXXXXX", envtmp ? envtmp : "/tmp"); 398 if (len < 0 || len >= (int)sizeof(path)) { 399 errno = ENAMETOOLONG; 400 return(-1); 401 } 402 403 (void)sigfillset(&set); 404 (void)_sigprocmask(SIG_BLOCK, &set, &oset); 405 if ((fd = mkostemp(path, O_CLOEXEC)) != -1) 406 (void)unlink(path); 407 (void)_sigprocmask(SIG_SETMASK, &oset, NULL); 408 return(fd); 409} 410 411static int 412byteorder(void) 413{ 414 u_int32_t x; 415 u_char *p; 416 417 x = 0x01020304; 418 p = (u_char *)&x; 419 switch (*p) { 420 case 1: 421 return (BIG_ENDIAN); 422 case 4: 423 return (LITTLE_ENDIAN); 424 default: 425 return (0); 426 } 427} 428 429int 430__bt_fd(const DB *dbp) 431{ 432 BTREE *t; 433 434 t = dbp->internal; 435 436 /* Toss any page pinned across calls. */ 437 if (t->bt_pinned != NULL) { 438 mpool_put(t->bt_mp, t->bt_pinned, 0); 439 t->bt_pinned = NULL; 440 } 441 442 /* In-memory database can't have a file descriptor. */ 443 if (F_ISSET(t, B_INMEM)) { 444 errno = ENOENT; 445 return (-1); 446 } 447 return (t->bt_fd); 448} 449