mpool: Refactor to call file operation via vtable.

Don't assume there's a POSIX system with read()/write(), etc., instead
accept function pointers to such routines via FILEVTABLE structure.

Other changes, like avoiding fstat() usage, using bundled version of BSD
sys/queue.h, etc.

PORT/include/bsd-queue.h

@@ -0,0 +1 @@
+queue.h

PORT/include/filevtable.h

@@ -0,0 +1 @@
+../../include/filevtable.h

include/filevtable.h

@@ -0,0 +1,54 @@
+/*-
+ * Copyright (c) 1991, 1993, 1994
+ *	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.
+ */
+
+#ifndef _BDB_FILEVTABLE_H_
+#define _BDB_FILEVTABLE_H_
+
+#ifdef VIRT_FD_T_HEADER
+#include VIRT_FD_T_HEADER
+#endif
+#include <sys/types.h>
+#include <unistd.h>
+
+#ifndef virt_fd_t
+#define virt_fd_t int
+#endif
+
+typedef struct FILEVTABLE {
+	ssize_t (*read) __P((virt_fd_t, void *, size_t));
+	ssize_t (*write) __P((virt_fd_t, const void *, size_t));
+	off_t   (*lseek) __P((virt_fd_t, off_t, int));
+	int     (*fsync) __P((virt_fd_t));
+} FILEVTABLE;
+
+#endif /* _BDB_FILEVTABLE_H_ */

include/mpool.h

@@ -33,7 +33,8 @@
  *	@(#)mpool.h	8.2 (Berkeley) 7/14/94
  */
 
-#include <sys/queue.h>
+#include <bsd-queue.h>
+#include <filevtable.h>
 
 /*
  * The memory pool scheme is a simple one.  Each in-memory page is referenced
@@ -65,8 +66,9 @@ typedef struct MPOOL {
 	pgno_t	maxcache;		/* max number of cached pages */
 	pgno_t	npages;			/* number of pages in the file */
 	u_long	pagesize;		/* file page size */
-	int	fd;			/* file descriptor */
+	virt_fd_t fd;			/* virtual file descriptor */
 					/* page in conversion routine */
+	const FILEVTABLE *fvtable;
 	void    (*pgin) __P((void *, pgno_t, void *));
 					/* page out conversion routine */
 	void    (*pgout) __P((void *, pgno_t, void *));
@@ -85,7 +87,7 @@ typedef struct MPOOL {
 } MPOOL;
 
 __BEGIN_DECLS
-MPOOL	*mpool_open __P((void *, int, pgno_t, pgno_t));
+MPOOL	*mpool_open __P((void *, virt_fd_t, const FILEVTABLE *, pgno_t, pgno_t));
 void	 mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *),
 	    void (*)(void *, pgno_t, void *), void *));
 void	*mpool_new __P((MPOOL *, pgno_t *));

mpool/mpool.c

@@ -36,14 +36,12 @@ static char sccsid[] = "@(#)mpool.c	8.5 (Berkeley) 7/26/94";
 #endif /* LIBC_SCCS and not lint */
 
 #include <sys/param.h>
-#include <sys/queue.h>
+#include <bsd-queue.h>
-#include <sys/stat.h>
 
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <unistd.h>
 
 #include <db.h>
 
@@ -59,28 +57,15 @@ static int  mpool_write __P((MPOOL *, BKT *));
  *	Initialize a memory pool.
  */
 MPOOL *
-mpool_open(key, fd, pagesize, maxcache)
+mpool_open(key, fd, fvtable, pagesize, maxcache)
 	void *key;
-	int fd;
+	virt_fd_t fd;
+	const FILEVTABLE * fvtable;
 	pgno_t pagesize, maxcache;
 {
-	struct stat sb;
 	MPOOL *mp;
 	int entry;
 
-	/*
-	 * Get information about the file.
-	 *
-	 * XXX
-	 * We don't currently handle pipes, although we should.
-	 */
-	if (fstat(fd, &sb))
-		return (NULL);
-	if (!S_ISREG(sb.st_mode)) {
-		errno = ESPIPE;
-		return (NULL);
-	}
-
 	/* Allocate and initialize the MPOOL cookie. */
 	if ((mp = (MPOOL *)calloc(1, sizeof(MPOOL))) == NULL)
 		return (NULL);
@@ -88,7 +73,11 @@ mpool_open(key, fd, pagesize, maxcache)
 	for (entry = 0; entry < HASHSIZE; ++entry)
 		CIRCLEQ_INIT(&mp->hqh[entry]);
 	mp->maxcache = maxcache;
-	mp->npages = sb.st_size / pagesize;
+	mp->fvtable = fvtable;
+	off_t file_size = mp->fvtable->lseek(fd, 0, SEEK_END);
+	if (file_size == (off_t)-1)
+		return (NULL);
+	mp->npages = file_size / pagesize;
 	mp->pagesize = pagesize;
 	mp->fd = fd;
 	return (mp);
@@ -203,9 +192,9 @@ mpool_get(mp, pgno, flags)
 	++mp->pageread;
 #endif
 	off = mp->pagesize * pgno;
-	if (lseek(mp->fd, off, SEEK_SET) != off)
+	if (mp->fvtable->lseek(mp->fd, off, SEEK_SET) != off)
 		return (NULL);
-	if ((nr = read(mp->fd, bp->page, mp->pagesize)) != mp->pagesize) {
+	if ((nr = mp->fvtable->read(mp->fd, bp->page, mp->pagesize)) != mp->pagesize) {
 		if (nr >= 0)
 			errno = EFTYPE;
 		return (NULL);
@@ -297,7 +286,7 @@ mpool_sync(mp)
 			return (RET_ERROR);
 
 	/* Sync the file descriptor. */
-	return (fsync(mp->fd) ? RET_ERROR : RET_SUCCESS);
+	return (mp->fvtable->fsync(mp->fd) ? RET_ERROR : RET_SUCCESS);
 }
 
 /*
@@ -378,9 +367,9 @@ mpool_write(mp, bp)
 		(mp->pgout)(mp->pgcookie, bp->pgno, bp->page);
 
 	off = mp->pagesize * bp->pgno;
-	if (lseek(mp->fd, off, SEEK_SET) != off)
+	if (mp->fvtable->lseek(mp->fd, off, SEEK_SET) != off)
 		return (RET_ERROR);
-	if (write(mp->fd, bp->page, mp->pagesize) != mp->pagesize)
+	if (mp->fvtable->write(mp->fd, bp->page, mp->pagesize) != mp->pagesize)
 		return (RET_ERROR);
 
 	bp->flags &= ~MPOOL_DIRTY;