383 lines
10 KiB
C
383 lines
10 KiB
C
/* $NetBSD: sliplogin.c,v 1.20 2003/10/21 02:53:57 fvdl Exp $ */
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/*-
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* Copyright (c) 1990, 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/cdefs.h>
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#ifndef lint
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__COPYRIGHT("@(#) Copyright (c) 1990, 1993\n\
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The Regents of the University of California. All rights reserved.\n");
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#endif /* not lint */
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#ifndef lint
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#if 0
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static char sccsid[] = "@(#)sliplogin.c 8.2 (Berkeley) 2/1/94";
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#else
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__RCSID("$NetBSD: sliplogin.c,v 1.20 2003/10/21 02:53:57 fvdl Exp $");
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#endif
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#endif /* not lint */
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/*
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* sliplogin.c
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* [MUST BE RUN SUID, SLOPEN DOES A SUSER()!]
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*
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* This program initializes its own tty port to be an async TCP/IP interface.
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* It sets the line discipline to slip, invokes a shell script to initialize
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* the network interface, then pauses forever waiting for hangup.
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*
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* It is a remote descendant of several similar programs with incestuous ties:
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* - Kirk Smith's slipconf, modified by Richard Johnsson @ DEC WRL.
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* - slattach, probably by Rick Adams but touched by countless hordes.
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* - the original sliplogin for 4.2bsd, Doug Kingston the mover behind it.
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*
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* There are two forms of usage:
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*
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* "sliplogin"
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* Invoked simply as "sliplogin", the program looks up the username
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* in the file /etc/slip.hosts.
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* If an entry is found, the line on fd0 is configured for SLIP operation
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* as specified in the file.
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*
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* "sliplogin IPhostlogin </dev/ttyb"
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* Invoked by root with a username, the name is looked up in the
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* /etc/slip.hosts file and if found fd0 is configured as in case 1.
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*/
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#include <sys/types.h>
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#include <sys/file.h>
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <sys/stat.h>
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#include <sys/syslog.h>
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#if BSD >= 199006
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#define POSIX
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#endif
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#ifdef POSIX
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#include <termios.h>
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#include <sys/ioctl.h>
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#include <ttyent.h>
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#else
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#include <sgtty.h>
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#endif
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#include <net/slip.h>
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#include <ctype.h>
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#include <err.h>
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#include <errno.h>
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#include <netdb.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "pathnames.h"
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int unit;
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int speed;
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int uid;
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char loginargs[BUFSIZ];
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char loginfile[MAXPATHLEN];
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char loginname[BUFSIZ];
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void findid __P((char *));
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void hup_handler __P((int));
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int main __P((int, char **));
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const char *sigstr __P((int));
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void
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findid(name)
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char *name;
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{
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FILE *fp;
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static char slopt[5][16];
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static char laddr[16];
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static char raddr[16];
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static char mask[16];
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char user[16];
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int n;
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(void)strlcpy(loginname, name, sizeof(loginname));
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if ((fp = fopen(_PATH_ACCESS, "r")) == NULL) {
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syslog(LOG_ERR, "%s: %m\n", _PATH_ACCESS);
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err(1, "%s", _PATH_ACCESS);
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}
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while (fgets(loginargs, sizeof(loginargs) - 1, fp)) {
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if (ferror(fp))
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break;
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n = sscanf(loginargs, "%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s%*[ \t]%15s\n",
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user, laddr, raddr, mask, slopt[0], slopt[1],
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slopt[2], slopt[3], slopt[4]);
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if (user[0] == '#' || isspace(user[0]))
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continue;
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if (strcmp(user, name) != 0)
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continue;
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/*
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* we've found the guy we're looking for -- see if
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* there's a login file we can use. First check for
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* one specific to this host. If none found, try for
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* a generic one.
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*/
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(void)snprintf(loginfile, sizeof loginfile, "%s.%s",
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_PATH_LOGIN, name);
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if (access(loginfile, R_OK|X_OK) != 0) {
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(void)strlcpy(loginfile, _PATH_LOGIN, sizeof(loginfile));
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if (access(loginfile, R_OK|X_OK)) {
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fputs("access denied - no login file\n",
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stderr);
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syslog(LOG_ERR,
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"access denied for %s - no %s\n",
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name, _PATH_LOGIN);
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exit(5);
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}
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}
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(void)fclose(fp);
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return;
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}
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syslog(LOG_ERR, "SLIP access denied for %s\n", name);
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errx(1, "SLIP access denied for %s", name);
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/* NOTREACHED */
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}
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const char *
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sigstr(s)
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int s;
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{
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if (s > 0 && s < NSIG)
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return (sys_signame[s]);
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else {
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static char buf[32];
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(void)snprintf(buf, sizeof buf, "sig %d", s);
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return (buf);
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}
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}
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void
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hup_handler(s)
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int s;
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{
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char logoutfile[MAXPATHLEN];
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(void)snprintf(logoutfile, sizeof logoutfile, "%s.%s", _PATH_LOGOUT,
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loginname);
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if (access(logoutfile, R_OK|X_OK) != 0)
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(void)strlcpy(logoutfile, _PATH_LOGOUT, sizeof(logoutfile));
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if (access(logoutfile, R_OK|X_OK) == 0) {
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char logincmd[2*MAXPATHLEN+32];
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(void)snprintf(logincmd, sizeof logincmd, "%s %d %d %s",
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logoutfile, unit, speed, loginargs);
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(void)system(logincmd);
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}
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(void)close(0);
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syslog(LOG_INFO, "closed %s slip unit %d (%s)\n", loginname, unit,
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sigstr(s));
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exit(1);
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/* NOTREACHED */
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}
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int
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main(argc, argv)
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int argc;
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char *argv[];
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{
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int fd, s, ldisc, odisc;
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char *name;
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#ifdef POSIX
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struct termios tios, otios;
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#else
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struct sgttyb tty, otty;
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#endif
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char logincmd[2*BUFSIZ+32];
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if (strlen(argv[0]) > MAXLOGNAME)
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errx(1, "login %s too long", argv[0]);
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if ((name = strrchr(argv[0], '/')) == NULL)
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name = argv[0];
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else
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name++;
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s = getdtablesize();
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for (fd = 3 ; fd < s ; fd++)
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(void)close(fd);
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openlog(name, LOG_PID, LOG_DAEMON);
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uid = getuid();
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if (argc > 1) {
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findid(argv[1]);
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/*
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* Disassociate from current controlling terminal, if any,
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* and ensure that the slip line is our controlling terminal.
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*/
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#ifdef POSIX
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switch (fork()) {
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case -1:
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perror("fork");
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syslog(LOG_ERR, "could not fork: %m");
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exit(1);
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case 0:
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break;
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default:
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exit(0);
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}
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if (setsid() < 0)
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perror("setsid");
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#else
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if ((fd = open("/dev/tty", O_RDONLY, 0)) >= 0) {
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extern char *ttyname();
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(void)ioctl(fd, TIOCNOTTY, (caddr_t)0);
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(void)close(fd);
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/* open slip tty again to acquire as controlling tty? */
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fd = open(ttyname(0), O_RDWR, 0);
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if (fd >= 0)
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(void)close(fd);
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}
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(void)setpgrp(0, getpid());
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#endif
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if (argc > 2) {
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if ((fd = open(argv[2], O_RDWR)) == -1) {
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perror(argv[2]);
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exit(2);
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}
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(void)dup2(fd, 0);
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if (fd > 2)
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close(fd);
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}
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#ifdef TIOCSCTTY
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if (ioctl(STDIN_FILENO, TIOCSCTTY, (caddr_t)0) != 0)
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perror("ioctl (TIOCSCTTY)");
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#endif
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} else {
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if ((name = getlogin()) == NULL) {
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syslog(LOG_ERR,
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"access denied - getlogin returned 0\n");
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errx(1, "access denied - no username");
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}
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findid(name);
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}
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if (!isatty(STDIN_FILENO)) {
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syslog(LOG_ERR, "stdin not a tty");
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errx(1, "stdin not a tty");
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}
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(void)fchmod(STDIN_FILENO, 0600);
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warnx("starting slip login for %s", loginname);
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#ifdef POSIX
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/* set up the line parameters */
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if (tcgetattr(STDIN_FILENO, &tios) < 0) {
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syslog(LOG_ERR, "tcgetattr: %m");
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exit(1);
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}
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otios = tios;
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cfmakeraw(&tios);
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tios.c_iflag &= ~IMAXBEL;
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if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &tios) < 0) {
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syslog(LOG_ERR, "tcsetattr: %m");
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exit(1);
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}
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speed = cfgetispeed(&tios);
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#else
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/* set up the line parameters */
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if (ioctl(STDIN_FILENO, TIOCGETP, (caddr_t)&tty) < 0) {
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syslog(LOG_ERR, "ioctl (TIOCGETP): %m");
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exit(1);
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}
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otty = tty;
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speed = tty.sg_ispeed;
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tty.sg_flags = RAW | ANYP;
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if (ioctl(STDIN_FILENO, TIOCSETP, (caddr_t)&tty) < 0) {
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syslog(LOG_ERR, "ioctl (TIOCSETP): %m");
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exit(1);
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}
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#endif
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/* find out what ldisc we started with */
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if (ioctl(STDIN_FILENO, TIOCGETD, (caddr_t)&odisc) < 0) {
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syslog(LOG_ERR, "ioctl(TIOCGETD) (1): %m");
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exit(1);
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}
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ldisc = SLIPDISC;
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if (ioctl(STDIN_FILENO, TIOCSETD, (caddr_t)&ldisc) < 0) {
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syslog(LOG_ERR, "ioctl(TIOCSETD): %m");
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exit(1);
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}
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/* find out what unit number we were assigned */
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if (ioctl(STDIN_FILENO, SLIOCGUNIT, (caddr_t)&unit) < 0) {
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syslog(LOG_ERR, "ioctl (SLIOCGUNIT): %m");
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exit(1);
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}
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(void)signal(SIGHUP, hup_handler);
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(void)signal(SIGTERM, hup_handler);
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syslog(LOG_INFO, "attaching slip unit %d for %s\n", unit, loginname);
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(void)snprintf(logincmd, sizeof logincmd, "%s %d %d %s", loginfile,
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unit, speed, loginargs);
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/*
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* aim stdout and errout at /dev/null so logincmd output won't
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* babble into the slip tty line.
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*/
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(void)close(1);
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if ((fd = open(_PATH_DEVNULL, O_WRONLY)) != 1) {
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if (fd < 0) {
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syslog(LOG_ERR, "open /dev/null: %m");
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exit(1);
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}
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(void)dup2(fd, 1);
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(void)close(fd);
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}
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(void)dup2(1, 2);
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/*
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* Run login and logout scripts as root (real and effective);
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* current route(8) is setuid root, and checks the real uid
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* to see whether changes are allowed (or just "route get").
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*/
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(void)setuid(0);
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if ((s = system(logincmd)) != 0) {
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syslog(LOG_ERR, "%s login failed: exit status %d from %s",
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loginname, s, loginfile);
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(void)ioctl(STDIN_FILENO, TIOCSETD, (caddr_t)&odisc);
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#ifdef POSIX
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(void)tcsetattr(STDIN_FILENO, TCSAFLUSH, &otios);
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#else
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(void)ioctl(STDIN_FILENO, TIOCSETP, (caddr_t)&otty);
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#endif
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exit(6);
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}
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/* twiddle thumbs until we get a signal */
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while (1)
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sigpause(0);
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/* NOTREACHED */
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}
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