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+++ Libc/Libc-262.3.2/db/mpool/mpool.c
@@ -0,0 +1,555 @@
+/*
+ * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ *
+ * Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved.
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_LICENSE_HEADER_END@
+ */
+/*
+ * Copyright (c) 1990, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * 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.
+ */
+
+
+#include <sys/param.h>
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <db.h>
+#define __MPOOLINTERFACE_PRIVATE
+#include "mpool.h"
+
+static BKT *mpool_bkt __P((MPOOL *));
+static BKT *mpool_look __P((MPOOL *, pgno_t));
+static int mpool_write __P((MPOOL *, BKT *));
+#ifdef DEBUG
+static void __mpoolerr __P((const char *fmt, ...));
+#endif
+
+/*
+ * MPOOL_OPEN -- initialize a memory pool.
+ *
+ * Parameters:
+ * key: Shared buffer key.
+ * fd: File descriptor.
+ * pagesize: File page size.
+ * maxcache: Max number of cached pages.
+ *
+ * Returns:
+ * MPOOL pointer, NULL on error.
+ */
+MPOOL *
+mpool_open(key, fd, pagesize, maxcache)
+ DBT *key;
+ int fd;
+ pgno_t pagesize, maxcache;
+{
+ struct stat sb;
+ MPOOL *mp;
+ int entry;
+
+ if (fstat(fd, &sb))
+ return (NULL);
+ /* XXX
+ * We should only set st_size to 0 for pipes -- 4.4BSD has the fix so
+ * that stat(2) returns true for ISSOCK on pipes. Until then, this is
+ * fairly close.
+ */
+ if (!S_ISREG(sb.st_mode)) {
+ errno = ESPIPE;
+ return (NULL);
+ }
+
+ if ((mp = (MPOOL *)malloc(sizeof(MPOOL))) == NULL)
+ return (NULL);
+ mp->free.cnext = mp->free.cprev = (BKT *)&mp->free;
+ mp->lru.cnext = mp->lru.cprev = (BKT *)&mp->lru;
+ for (entry = 0; entry < HASHSIZE; ++entry)
+ mp->hashtable[entry].hnext = mp->hashtable[entry].hprev =
+ mp->hashtable[entry].cnext = mp->hashtable[entry].cprev =
+ (BKT *)&mp->hashtable[entry];
+ mp->curcache = 0;
+ mp->maxcache = maxcache;
+ mp->pagesize = pagesize;
+ mp->npages = sb.st_size / pagesize;
+ mp->fd = fd;
+ mp->pgcookie = NULL;
+ mp->pgin = mp->pgout = NULL;
+
+#ifdef STATISTICS
+ mp->cachehit = mp->cachemiss = mp->pagealloc = mp->pageflush =
+ mp->pageget = mp->pagenew = mp->pageput = mp->pageread =
+ mp->pagewrite = 0;
+#endif
+ return (mp);
+}
+
+/*
+ * MPOOL_FILTER -- initialize input/output filters.
+ *
+ * Parameters:
+ * pgin: Page in conversion routine.
+ * pgout: Page out conversion routine.
+ * pgcookie: Cookie for page in/out routines.
+ */
+void
+mpool_filter(mp, pgin, pgout, pgcookie)
+ MPOOL *mp;
+ void (*pgin) __P((void *, pgno_t, void *));
+ void (*pgout) __P((void *, pgno_t, void *));
+ void *pgcookie;
+{
+ mp->pgin = pgin;
+ mp->pgout = pgout;
+ mp->pgcookie = pgcookie;
+}
+
+/*
+ * MPOOL_NEW -- get a new page
+ *
+ * Parameters:
+ * mp: mpool cookie
+ * pgnoadddr: place to store new page number
+ * Returns:
+ * RET_ERROR, RET_SUCCESS
+ */
+void *
+mpool_new(mp, pgnoaddr)
+ MPOOL *mp;
+ pgno_t *pgnoaddr;
+{
+ BKT *b;
+ BKTHDR *hp;
+
+#ifdef STATISTICS
+ ++mp->pagenew;
+#endif
+ /*
+ * Get a BKT from the cache. Assign a new page number, attach it to
+ * the hash and lru chains and return.
+ */
+ if ((b = mpool_bkt(mp)) == NULL)
+ return (NULL);
+ *pgnoaddr = b->pgno = mp->npages++;
+ b->flags = MPOOL_PINNED;
+ inshash(b, b->pgno);
+ inschain(b, &mp->lru);
+ return (b->page);
+}
+
+/*
+ * MPOOL_GET -- get a page from the pool
+ *
+ * Parameters:
+ * mp: mpool cookie
+ * pgno: page number
+ * flags: not used
+ *
+ * Returns:
+ * RET_ERROR, RET_SUCCESS
+ */
+void *
+mpool_get(mp, pgno, flags)
+ MPOOL *mp;
+ pgno_t pgno;
+ u_int flags; /* XXX not used? */
+{
+ BKT *b;
+ BKTHDR *hp;
+ off_t off;
+ int nr;
+
+ /*
+ * If asking for a specific page that is already in the cache, find
+ * it and return it.
+ */
+ if (b = mpool_look(mp, pgno)) {
+#ifdef STATISTICS
+ ++mp->pageget;
+#endif
+#ifdef DEBUG
+ if (b->flags & MPOOL_PINNED)
+ __mpoolerr("mpool_get: page %d already pinned",
+ b->pgno);
+#endif
+ rmchain(b);
+ inschain(b, &mp->lru);
+ b->flags |= MPOOL_PINNED;
+ return (b->page);
+ }
+
+ /* Not allowed to retrieve a non-existent page. */
+ if (pgno >= mp->npages) {
+ errno = EINVAL;
+ return (NULL);
+ }
+
+ /* Get a page from the cache. */
+ if ((b = mpool_bkt(mp)) == NULL)
+ return (NULL);
+ b->pgno = pgno;
+ b->flags = MPOOL_PINNED;
+
+#ifdef STATISTICS
+ ++mp->pageread;
+#endif
+ /* Read in the contents. */
+ off = mp->pagesize * pgno;
+ if (lseek(mp->fd, off, SEEK_SET) != off)
+ return (NULL);
+ if ((nr = read(mp->fd, b->page, mp->pagesize)) != mp->pagesize) {
+ if (nr >= 0)
+ errno = EFTYPE;
+ return (NULL);
+ }
+ if (mp->pgin)
+ (mp->pgin)(mp->pgcookie, b->pgno, b->page);
+
+ inshash(b, b->pgno);
+ inschain(b, &mp->lru);
+#ifdef STATISTICS
+ ++mp->pageget;
+#endif
+ return (b->page);
+}
+
+/*
+ * MPOOL_PUT -- return a page to the pool
+ *
+ * Parameters:
+ * mp: mpool cookie
+ * page: page pointer
+ * pgno: page number
+ *
+ * Returns:
+ * RET_ERROR, RET_SUCCESS
+ */
+int
+mpool_put(mp, page, flags)
+ MPOOL *mp;
+ void *page;
+ u_int flags;
+{
+ BKT *baddr;
+#ifdef DEBUG
+ BKT *b;
+#endif
+
+#ifdef STATISTICS
+ ++mp->pageput;
+#endif
+ baddr = (BKT *)((char *)page - sizeof(BKT));
+#ifdef DEBUG
+ if (!(baddr->flags & MPOOL_PINNED))
+ __mpoolerr("mpool_put: page %d not pinned", b->pgno);
+ for (b = mp->lru.cnext; b != (BKT *)&mp->lru; b = b->cnext) {
+ if (b == (BKT *)&mp->lru)
+ __mpoolerr("mpool_put: %0x: bad address", baddr);
+ if (b == baddr)
+ break;
+ }
+#endif
+ baddr->flags &= ~MPOOL_PINNED;
+ baddr->flags |= flags & MPOOL_DIRTY;
+ return (RET_SUCCESS);
+}
+
+/*
+ * MPOOL_CLOSE -- close the buffer pool
+ *
+ * Parameters:
+ * mp: mpool cookie
+ *
+ * Returns:
+ * RET_ERROR, RET_SUCCESS
+ */
+int
+mpool_close(mp)
+ MPOOL *mp;
+{
+ BKT *b, *next;
+
+ /* Free up any space allocated to the lru pages. */
+ for (b = mp->lru.cprev; b != (BKT *)&mp->lru; b = next) {
+ next = b->cprev;
+ free(b);
+ }
+ free(mp);
+ return (RET_SUCCESS);
+}
+
+/*
+ * MPOOL_SYNC -- sync the file to disk.
+ *
+ * Parameters:
+ * mp: mpool cookie
+ *
+ * Returns:
+ * RET_ERROR, RET_SUCCESS
+ */
+int
+mpool_sync(mp)
+ MPOOL *mp;
+{
+ BKT *b;
+
+ for (b = mp->lru.cprev; b != (BKT *)&mp->lru; b = b->cprev)
+ if (b->flags & MPOOL_DIRTY && mpool_write(mp, b) == RET_ERROR)
+ return (RET_ERROR);
+ return (fsync(mp->fd) ? RET_ERROR : RET_SUCCESS);
+}
+
+/*
+ * MPOOL_BKT -- get/create a BKT from the cache
+ *
+ * Parameters:
+ * mp: mpool cookie
+ *
+ * Returns:
+ * NULL on failure and a pointer to the BKT on success
+ */
+static BKT *
+mpool_bkt(mp)
+ MPOOL *mp;
+{
+ BKT *b;
+
+ if (mp->curcache < mp->maxcache)
+ goto new;
+
+ /*
+ * If the cache is maxxed out, search the lru list for a buffer we
+ * can flush. If we find one, write it if necessary and take it off
+ * any lists. If we don't find anything we grow the cache anyway.
+ * The cache never shrinks.
+ */
+ for (b = mp->lru.cprev; b != (BKT *)&mp->lru; b = b->cprev)
+ if (!(b->flags & MPOOL_PINNED)) {
+ if (b->flags & MPOOL_DIRTY &&
+ mpool_write(mp, b) == RET_ERROR)
+ return (NULL);
+ rmhash(b);
+ rmchain(b);
+#ifdef STATISTICS
+ ++mp->pageflush;
+#endif
+#ifdef DEBUG
+ {
+ void *spage;
+ spage = b->page;
+ memset(b, 0xff, sizeof(BKT) + mp->pagesize);
+ b->page = spage;
+ }
+#endif
+ return (b);
+ }
+
+new: if ((b = (BKT *)malloc(sizeof(BKT) + mp->pagesize)) == NULL)
+ return (NULL);
+#ifdef STATISTICS
+ ++mp->pagealloc;
+#endif
+#ifdef DEBUG
+ memset(b, 0xff, sizeof(BKT) + mp->pagesize);
+#endif
+ b->page = (char *)b + sizeof(BKT);
+ ++mp->curcache;
+ return (b);
+}
+
+/*
+ * MPOOL_WRITE -- sync a page to disk
+ *
+ * Parameters:
+ * mp: mpool cookie
+ *
+ * Returns:
+ * RET_ERROR, RET_SUCCESS
+ */
+static int
+mpool_write(mp, b)
+ MPOOL *mp;
+ BKT *b;
+{
+ off_t off;
+
+ if (mp->pgout)
+ (mp->pgout)(mp->pgcookie, b->pgno, b->page);
+
+#ifdef STATISTICS
+ ++mp->pagewrite;
+#endif
+ off = mp->pagesize * b->pgno;
+ if (lseek(mp->fd, off, SEEK_SET) != off)
+ return (RET_ERROR);
+ if (write(mp->fd, b->page, mp->pagesize) != mp->pagesize)
+ return (RET_ERROR);
+ b->flags &= ~MPOOL_DIRTY;
+ return (RET_SUCCESS);
+}
+
+/*
+ * MPOOL_LOOK -- lookup a page
+ *
+ * Parameters:
+ * mp: mpool cookie
+ * pgno: page number
+ *
+ * Returns:
+ * NULL on failure and a pointer to the BKT on success
+ */
+static BKT *
+mpool_look(mp, pgno)
+ MPOOL *mp;
+ pgno_t pgno;
+{
+ register BKT *b;
+ register BKTHDR *tb;
+
+ /* XXX
+ * If find the buffer, put it first on the hash chain so can
+ * find it again quickly.
+ */
+ tb = &mp->hashtable[HASHKEY(pgno)];
+ for (b = tb->hnext; b != (BKT *)tb; b = b->hnext)
+ if (b->pgno == pgno) {
+#ifdef STATISTICS
+ ++mp->cachehit;
+#endif
+ return (b);
+ }
+#ifdef STATISTICS
+ ++mp->cachemiss;
+#endif
+ return (NULL);
+}
+
+#ifdef STATISTICS
+/*
+ * MPOOL_STAT -- cache statistics
+ *
+ * Parameters:
+ * mp: mpool cookie
+ */
+void
+mpool_stat(mp)
+ MPOOL *mp;
+{
+ BKT *b;
+ int cnt;
+ char *sep;
+
+ (void)fprintf(stderr, "%lu pages in the file\n", mp->npages);
+ (void)fprintf(stderr,
+ "page size %lu, cacheing %lu pages of %lu page max cache\n",
+ mp->pagesize, mp->curcache, mp->maxcache);
+ (void)fprintf(stderr, "%lu page puts, %lu page gets, %lu page new\n",
+ mp->pageput, mp->pageget, mp->pagenew);
+ (void)fprintf(stderr, "%lu page allocs, %lu page flushes\n",
+ mp->pagealloc, mp->pageflush);
+ if (mp->cachehit + mp->cachemiss)
+ (void)fprintf(stderr,
+ "%.0f%% cache hit rate (%lu hits, %lu misses)\n",
+ ((double)mp->cachehit / (mp->cachehit + mp->cachemiss))
+ * 100, mp->cachehit, mp->cachemiss);
+ (void)fprintf(stderr, "%lu page reads, %lu page writes\n",
+ mp->pageread, mp->pagewrite);
+
+ sep = "";
+ cnt = 0;
+ for (b = mp->lru.cnext; b != (BKT *)&mp->lru; b = b->cnext) {
+ (void)fprintf(stderr, "%s%d", sep, b->pgno);
+ if (b->flags & MPOOL_DIRTY)
+ (void)fprintf(stderr, "d");
+ if (b->flags & MPOOL_PINNED)
+ (void)fprintf(stderr, "P");
+ if (++cnt == 10) {
+ sep = "\n";
+ cnt = 0;
+ } else
+ sep = ", ";
+
+ }
+ (void)fprintf(stderr, "\n");
+}
+#endif
+
+#ifdef DEBUG
+#if __STDC__
+#include <stdarg.h>
+#else
+#include <varargs.h>
+#endif
+
+static void
+#if __STDC__
+__mpoolerr(const char *fmt, ...)
+#else
+__mpoolerr(fmt, va_alist)
+ char *fmt;
+ va_dcl
+#endif
+{
+ va_list ap;
+#if __STDC__
+ va_start(ap, fmt);
+#else
+ va_start(ap);
+#endif
+ (void)vfprintf(stderr, fmt, ap);
+ va_end(ap);
+ (void)fprintf(stderr, "\n");
+ abort();
+ /* NOTREACHED */
+}
+#endif