d91a4a5990
overhead not to go look it up a zillion times when running fstat or ps on a machine with a billion people logged in. fstat mostly.
192 lines
6.4 KiB
C
192 lines
6.4 KiB
C
/* $NetBSD: devname.c,v 1.16 2004/12/16 04:33:03 atatat Exp $ */
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/*-
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* Copyright (c) 2000 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Simon Burge.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*-
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* Copyright (c) 1992 Keith Muller.
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* Copyright (c) 1989, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Keith Muller of the University of California, San Diego.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#if defined(LIBC_SCCS) && !defined(lint)
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#if 0
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static char sccsid[] = "@(#)devname.c 8.2 (Berkeley) 4/29/95";
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#else
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__RCSID("$NetBSD: devname.c,v 1.16 2004/12/16 04:33:03 atatat Exp $");
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#endif
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#endif /* LIBC_SCCS and not lint */
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#include "namespace.h"
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/param.h>
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#include <db.h>
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#include <fcntl.h>
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#include <paths.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <err.h>
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#ifdef __weak_alias
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__weak_alias(devname,_devname)
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#endif
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#define DEV_SZ 317 /* show be prime for best results */
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#define VALID 1 /* entry and devname are valid */
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#define INVALID 2 /* entry valid, devname NOT valid */
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typedef struct devc {
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int valid; /* entry valid? */
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dev_t dev; /* cached device */
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mode_t type; /* cached file type */
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char name[NAME_MAX]; /* device name */
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} DEVC;
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char *
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devname(dev, type)
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dev_t dev;
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mode_t type;
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{
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struct {
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mode_t type;
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dev_t dev;
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} bkey;
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static DB *db;
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static int failure;
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DBT data, key;
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DEVC *ptr, **pptr;
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static DEVC **devtb = NULL;
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static dev_t pts = (dev_t)~1;
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if (!db && !failure &&
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!(db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL))) {
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warn("warning: %s", _PATH_DEVDB);
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failure = 1;
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}
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/* initialise dev cache */
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if (!failure && devtb == NULL) {
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devtb = (DEVC **)calloc(DEV_SZ, sizeof(DEVC *));
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if (devtb == NULL)
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failure= 1;
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}
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if (failure)
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return (NULL);
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/* see if we have this dev/type cached */
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pptr = devtb + ((dev + type) % DEV_SZ);
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ptr = *pptr;
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if (ptr && ptr->valid > 0 && ptr->dev == dev && ptr->type == type) {
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if (ptr->valid == VALID)
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return (ptr->name);
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return (NULL);
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}
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if (ptr == NULL)
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*pptr = ptr = (DEVC *)malloc(sizeof(DEVC));
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/*
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* Keys are a mode_t followed by a dev_t. The former is the type of
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* the file (mode & S_IFMT), the latter is the st_rdev field. Be
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* sure to clear any padding that may be found in bkey.
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*/
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memset(&bkey, 0, sizeof(bkey));
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bkey.dev = dev;
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bkey.type = type;
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key.data = &bkey;
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key.size = sizeof(bkey);
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if ((db->get)(db, &key, &data, 0) == 0) {
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if (ptr == NULL)
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return (char *)data.data;
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ptr->dev = dev;
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ptr->type = type;
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strncpy(ptr->name, (char *)data.data, NAME_MAX);
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ptr->name[NAME_MAX - 1] = '\0';
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ptr->valid = VALID;
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} else {
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if (ptr == NULL)
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return (NULL);
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ptr->valid = INVALID;
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if (type == S_IFCHR) {
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if (pts == (dev_t)~1)
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pts = getdevmajor("pts", S_IFCHR);
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if (pts != (dev_t)~0 && major(dev) == pts) {
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(void)snprintf(ptr->name, sizeof(ptr->name),
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"%s%d", _PATH_DEV_PTS +
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sizeof(_PATH_DEV) - 1, minor(dev));
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ptr->valid = VALID;
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}
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}
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ptr->dev = dev;
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ptr->type = type;
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}
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if (ptr->valid == VALID)
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return (ptr->name);
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else
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return (NULL);
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}
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