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authorRoland McGrath <roland@gnu.org>1996-01-02 08:57:42 +0000
committerRoland McGrath <roland@gnu.org>1996-01-02 08:57:42 +0000
commit71733723fb421bd54467d1a27096463ed1dcc2ed (patch)
treef304556d491722c797d876911834dc4afbfa2740 /db/btree/bt_open.c
parentfc4026d8e43407ba2739e493878d1ce259500059 (diff)
downloadglibc-71733723fb421bd54467d1a27096463ed1dcc2ed.tar.gz
glibc-71733723fb421bd54467d1a27096463ed1dcc2ed.tar.xz
glibc-71733723fb421bd54467d1a27096463ed1dcc2ed.zip
* hurd/hurd/signal.h (struct hurd_sigstate): New member `preempters'. cvs/libc-960102
	(hurd_preempt_signals, hurd_unpreempt_signals): Decls removed.
	* hurd/hurd/sigpreempt.h: New file.
	* hurd/preempt-sig.c: Rewritten with new interface.
	* sysdeps/mach/hurd/jmp-unwind.c (_longjmp_unwind): Remove local signal
	preempters being unwound past.

	* db: New directory, 4.4 BSD db package incorporated from BSD db-1.85
	release.

	* sysdeps/unix/sysv/linux/sys/param.h: Several new macros for BSD
	compatibility.
Diffstat (limited to 'db/btree/bt_open.c')
-rw-r--r--db/btree/bt_open.c444
1 files changed, 444 insertions, 0 deletions
diff --git a/db/btree/bt_open.c b/db/btree/bt_open.c
new file mode 100644
index 0000000000..f052249777
--- /dev/null
+++ b/db/btree/bt_open.c
@@ -0,0 +1,444 @@
+/*-
+ * 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 <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) {
+			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))
+			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;
+	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 (F_ISSET(t, B_INMEM)) {
+		errno = ENOENT;
+		return (-1);
+	}
+	return (t->bt_fd);
+}