freebsd-dev/lib/libc/db/btree/bt_open.c
Daniel Eischen d201fe46e3 Remove _THREAD_SAFE and make libc thread-safe by default by
adding (weak definitions to) stubs for some of the pthread
functions.  If the threads library is linked in, the real
pthread functions will pulled in.

Use the following convention for system calls wrapped by the
threads library:
	__sys_foo - actual system call
	_foo - weak definition to __sys_foo
	foo - weak definition to __sys_foo

Change all libc uses of system calls wrapped by the threads
library from foo to _foo.  In order to define the prototypes
for _foo(), we introduce namespace.h and un-namespace.h
(suggested by bde).  All files that need to reference these
system calls, should include namespace.h before any standard
includes, then include un-namespace.h after the standard
includes and before any local includes.  <db.h> is an exception
and shouldn't be included in between namespace.h and
un-namespace.h  namespace.h will define foo to _foo, and
un-namespace.h will undefine foo.

Try to eliminate some of the recursive calls to MT-safe
functions in libc/stdio in preparation for adding a mutex
to FILE.  We have recursive mutexes, but would like to avoid
using them if possible.

Remove uneeded includes of <errno.h> from a few files.

Add $FreeBSD$ to a few files in order to pass commitprep.

Approved by:	-arch
2001-01-24 13:01:12 +00:00

450 lines
11 KiB
C

/*-
* 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.
*
* $FreeBSD$
*/
#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 "namespace.h"
#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 "un-namespace.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 = NULL;
char path[MAXPATHLEN];
if (issetugid() == 0)
envtmp = getenv("TMPDIR");
(void)snprintf(path,
sizeof(path), "%s/bt.XXXXXXXXXX", 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);
}