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-rw-r--r--utils/db1-ast/btree/bt_open.c458
1 files changed, 458 insertions, 0 deletions
diff --git a/utils/db1-ast/btree/bt_open.c b/utils/db1-ast/btree/bt_open.c
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+++ b/utils/db1-ast/btree/bt_open.c
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+/*-
+ * 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
+ * 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.
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)bt_open.c 8.10 (Berkeley) 8/17/94";
+#endif /* LIBC_SCCS and not lint */
+
+/*
+ * 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 "../include/db.h"
+#include "btree.h"
+
+#ifdef DEBUG
+#undef MINPSIZE
+#define MINPSIZE 128
+#endif
+
+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_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;
+ memset(t->bt_dbp, 0, sizeof(DB));
+ if (t->bt_lorder != machine_lorder)
+ F_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:
+ F_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;
+ F_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) {
+ if ((nr = read(t->bt_fd, &m, sizeof(BTMETA))) < 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.magic == BTREEMAGIC)
+ F_CLR(t, B_NEEDSWAP);
+ else {
+ F_SET(t, B_NEEDSWAP);
+ M_32_SWAP(m.magic);
+ M_32_SWAP(m.version);
+ M_32_SWAP(m.psize);
+ M_32_SWAP(m.free);
+ M_32_SWAP(m.nrecs);
+ M_32_SWAP(m.flags);
+ }
+ if (m.magic != BTREEMAGIC || m.version != BTREEVERSION)
+ goto eftype;
+ if (m.psize < MINPSIZE || m.psize > MAX_PAGE_OFFSET + 1 ||
+ m.psize & (sizeof(indx_t) - 1))
+ goto eftype;
+ if (m.flags & ~SAVEMETA)
+ goto eftype;
+ b.psize = m.psize;
+ F_SET(t, m.flags);
+ t->bt_free = m.free;
+ t->bt_nrecs = 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) {
+#ifdef _STATBUF_ST_BLKSIZE
+ b.psize = sb.st_blksize;
+#endif
+ 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))
+ F_SET(t, B_NODUPS);
+
+ t->bt_free = P_INVALID;
+ t->bt_nrecs = 0;
+ F_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 (!F_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)
+ F_SET(t, B_DB_LOCK);
+ if (dflags & DB_SHMEM)
+ F_SET(t, B_DB_SHMEM);
+ if (dflags & DB_TXN)
+ F_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) /* It's OK to not exist. */
+ return (RET_ERROR);
+ errno = 0;
+
+ 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;
+ const char *envtmp;
+ char *path;
+ static const char fmt[] = "%s/bt.XXXXXX";
+ size_t n;
+
+ envtmp = getenv("TMPDIR");
+ if (!envtmp)
+ envtmp = "/tmp";
+ n = strlen (envtmp) + sizeof fmt;
+#ifdef __GNUC__
+ path = __builtin_alloca(n);
+#else
+ path = malloc(n);
+#endif
+ (void)snprintf(path, n, fmt, 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);
+#ifndef __GNUC__
+ free(path);
+#endif
+ 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 (F_ISSET(t, B_INMEM)) {
+ errno = ENOENT;
+ return (-1);
+ }
+ return (t->bt_fd);
+}