73 lines
2.7 KiB
C
73 lines
2.7 KiB
C
/* $OpenBSD: login.c,v 1.11 2015/12/28 20:11:36 guenther Exp $ */
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/*
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* Copyright (c) 1988, 1993
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* The Regents of the University of California. All rights reserved.
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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/types.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <utmp.h>
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#include <stdio.h>
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#include <string.h>
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#include "util.h"
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void
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login(struct utmp *utp)
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{
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struct utmp old_ut;
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int fd, tty;
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off_t pos;
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tty = ttyslot();
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if (tty > 0 && (fd = open(_PATH_UTMP, O_RDWR|O_CREAT|O_CLOEXEC, 0644))
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>= 0) {
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/*
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* Prevent luser from zero'ing out ut_host.
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* If the new ut_line is empty but the old one is not
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* and ut_line and ut_name match, preserve the old ut_line.
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*/
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pos = (off_t)tty * sizeof(struct utmp);
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if (utp->ut_host[0] == '\0' &&
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pread(fd, &old_ut, sizeof(struct utmp), pos) ==
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sizeof(struct utmp) &&
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old_ut.ut_host[0] != '\0' &&
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strncmp(old_ut.ut_line, utp->ut_line, UT_LINESIZE) == 0 &&
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strncmp(old_ut.ut_name, utp->ut_name, UT_NAMESIZE) == 0)
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(void)memcpy(utp->ut_host, old_ut.ut_host, UT_HOSTSIZE);
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(void)pwrite(fd, utp, sizeof(struct utmp), pos);
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(void)close(fd);
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}
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if ((fd = open(_PATH_WTMP, O_WRONLY|O_APPEND|O_CLOEXEC)) >= 0) {
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(void)write(fd, utp, sizeof(struct utmp));
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(void)close(fd);
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}
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}
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