202 lines
6.0 KiB
C
202 lines
6.0 KiB
C
/* $NetBSD: pt_file.c,v 1.13 2001/01/10 03:33:16 lukem Exp $ */
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/*
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* Copyright (c) 1992, 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 donated to Berkeley by
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* Jan-Simon Pendry.
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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 University of
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* California, Berkeley and its contributors.
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* 4. 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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* from: Id: pt_file.c,v 1.1 1992/05/25 21:43:09 jsp Exp
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* @(#)pt_file.c 8.3 (Berkeley) 7/3/94
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*/
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#include <sys/cdefs.h>
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#ifndef lint
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__RCSID("$NetBSD: pt_file.c,v 1.13 2001/01/10 03:33:16 lukem Exp $");
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#endif /* not lint */
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#include <stdio.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <sys/types.h>
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#include <sys/param.h>
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#include <sys/syslog.h>
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#include "portald.h"
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#ifdef DEBUG
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#define DEBUG_SYSLOG syslog
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#else
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/*
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* The "if (0) ..." will be optimized away by the compiler if
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* DEBUG is not defined.
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*/
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#define DEBUG_SYSLOG if (0) syslog
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#endif
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int
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lose_credentials(pcr)
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struct portal_cred *pcr;
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{
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/*
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* If we are root, then switch into the caller's credentials.
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* By the way, we _always_ log failures, to make
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* sure questionable activity is noticed.
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*/
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if (getuid() == 0) {
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/* Set groups first ... */
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if (setgroups(pcr->pcr_ngroups, pcr->pcr_groups) < 0) {
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syslog(LOG_WARNING,
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"lose_credentials: setgroups() failed (%m)");
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return (errno);
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}
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/* ... then gid ... */
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if (setgid(pcr->pcr_gid) < 0) {
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syslog(LOG_WARNING,
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"lose_credentials: setgid(%d) failed (%m)",
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pcr->pcr_gid);
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}
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/*
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* ... and now do the setuid() where we lose all special
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* powers (both real and effective userid).
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*/
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if (setuid(pcr->pcr_uid) < 0) {
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syslog(LOG_WARNING,
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"lose_credentials: setuid(%d) failed (%m)",
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pcr->pcr_uid);
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}
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/* The credential change was successful! */
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DEBUG_SYSLOG(LOG_DEBUG, "Root-owned mount process lowered credentials -- returning successfully!\n");
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return 0;
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}
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DEBUG_SYSLOG(LOG_DEBUG, "Actual/effective/caller's creds are:");
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DEBUG_SYSLOG(LOG_DEBUG, "%d/%d %d/%d %d/%d", getuid(),
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getgid(), geteuid(), getegid(), pcr->pcr_uid, pcr->pcr_gid);
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/*
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* Else, fail if the uid is neither actual or effective
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* uid of mount process...
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*/
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if ((getuid() != pcr->pcr_uid) && (geteuid() != pcr->pcr_uid)) {
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syslog(LOG_WARNING,
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"lose_credentials: uid %d != uid %d, or euid %d != uid %d",
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getuid(), pcr->pcr_uid, geteuid(), pcr->pcr_uid);
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return EPERM;
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}
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/*
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* ... or the gid is neither the actual or effective
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* gid of the mount process.
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*/
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if ((getgid() != pcr->pcr_gid) && (getegid() != pcr->pcr_gid)) {
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syslog(LOG_WARNING,
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"lose_credentials: gid %d != gid %d, or egid %d != gid %d",
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getgid(), pcr->pcr_gid, getegid(), pcr->pcr_gid);
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return EPERM;
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}
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/*
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* If we make it here, we have a uid _and_ gid match! Allow the
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* access.
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*/
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DEBUG_SYSLOG(LOG_DEBUG, "Returning successfully!\n");
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return 0;
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}
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int
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portal_file(pcr, key, v, so, fdp)
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struct portal_cred *pcr;
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char *key;
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char **v;
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int so;
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int *fdp;
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{
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int fd;
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char pbuf[MAXPATHLEN];
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int error;
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int origuid, origgid;
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origuid = getuid();
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origgid = getgid();
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pbuf[0] = '/';
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strcpy(pbuf + 1, key + (v[1] ? strlen(v[1]) : 0));
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DEBUG_SYSLOG(LOG_DEBUG, "path = %s, uid = %d, gid = %d",
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pbuf, pcr->pcr_uid, pcr->pcr_gid);
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if ((error = lose_credentials(pcr)) != 0) {
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DEBUG_SYSLOG(LOG_DEBUG, "portal_file: Credential err %d", error);
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return error;
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}
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error = 0;
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/*
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* Be careful -- only set error to errno if there is an error.
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* errno could hold an old, uncaught value, from a routine
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* called long before now.
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*/
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fd = open(pbuf, O_RDWR | O_CREAT, 0666);
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if (fd < 0) {
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error = errno;
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if (error == EACCES) {
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DEBUG_SYSLOG(LOG_DEBUG, "Error: could not open '%s' "
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"read/write with create flag. "
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"Trying read-only open...", pbuf);
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/* Try opening read-only. */
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fd = open(pbuf, O_RDONLY, 0);
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if (fd < 0) {
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error = errno;
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DEBUG_SYSLOG(LOG_DEBUG, "That failed too! %m");
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} else {
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/* Clear the error indicator. */
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error = 0;
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}
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} else {
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DEBUG_SYSLOG(LOG_DEBUG, "Error: could not open '%s': %m", pbuf);
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}
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}
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if (seteuid((uid_t) origuid) < 0) { /* XXX - should reset gidset
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* too */
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error = errno;
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syslog(LOG_WARNING, "setcred: %m");
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if (fd >= 0) {
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(void) close(fd);
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fd = -1;
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}
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}
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if (error == 0)
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*fdp = fd;
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DEBUG_SYSLOG(LOG_DEBUG, "pt_file returns *fdp = %d, error = %d", *fdp,
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error);
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return (error);
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}
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