xref: /illumos-gate/usr/src/cmd/cmd-inet/usr.bin/pppd/main.c (revision 88f8b78a88cbdc6d8c1af5c3e54bc49d25095c98)
1 /*
2  * main.c - Point-to-Point Protocol main module
3  *
4  * Copyright 2000-2002 Sun Microsystems, Inc.  All rights reserved.
5  * Use is subject to license terms.
6  *
7  * Permission to use, copy, modify, and distribute this software and its
8  * documentation is hereby granted, provided that the above copyright
9  * notice appears in all copies.
10  *
11  * SUN MAKES NO REPRESENTATION OR WARRANTIES ABOUT THE SUITABILITY OF
12  * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
13  * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
14  * PARTICULAR PURPOSE, OR NON-INFRINGEMENT.  SUN SHALL NOT BE LIABLE FOR
15  * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
16  * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES
17  *
18  * Copyright (c) 1989 Carnegie Mellon University.
19  * All rights reserved.
20  *
21  * Redistribution and use in source and binary forms are permitted
22  * provided that the above copyright notice and this paragraph are
23  * duplicated in all such forms and that any documentation,
24  * advertising materials, and other materials related to such
25  * distribution and use acknowledge that the software was developed
26  * by Carnegie Mellon University.  The name of the
27  * University may not be used to endorse or promote products derived
28  * from this software without specific prior written permission.
29  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
30  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
31  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
32  */
33 
34 #pragma ident	"%Z%%M%	%I%	%E% SMI"
35 #define RCSID	"$Id: main.c,v 1.97 2000/04/24 02:54:16 masputra Exp $"
36 
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <string.h>
40 #include <unistd.h>
41 #include <signal.h>
42 #include <errno.h>
43 #include <fcntl.h>
44 #include <syslog.h>
45 #include <netdb.h>
46 #include <pwd.h>
47 #include <setjmp.h>
48 #include <sys/param.h>
49 #include <sys/types.h>
50 #include <sys/wait.h>
51 #include <sys/time.h>
52 #include <sys/resource.h>
53 #include <sys/stat.h>
54 #include <sys/socket.h>
55 #include <netinet/in.h>
56 #include <arpa/inet.h>
57 
58 #include "pppd.h"
59 #include "magic.h"
60 #include "fsm.h"
61 #include "lcp.h"
62 #include "ipcp.h"
63 #ifdef INET6
64 #include "ipv6cp.h"
65 #endif
66 #include "upap.h"
67 #include "chap.h"
68 #include "ccp.h"
69 #include "pathnames.h"
70 #include "patchlevel.h"
71 
72 #ifdef HAVE_MULTILINK
73 #include "tdb.h"
74 #endif
75 
76 #ifdef CBCP_SUPPORT
77 #include "cbcp.h"
78 #endif
79 
80 #ifdef IPX_CHANGE
81 #include "ipxcp.h"
82 #endif /* IPX_CHANGE */
83 #ifdef AT_CHANGE
84 #include "atcp.h"
85 #endif
86 
87 #if !defined(lint) && !defined(_lint)
88 static const char rcsid[] = RCSID;
89 #endif
90 
91 /* interface vars */
92 char ifname[32];		/* Interface name */
93 int ifunit = -1;		/* Interface unit number */
94 
95 char *progname;			/* Name of this program */
96 char hostname[MAXHOSTNAMELEN+1]; /* Our hostname */
97 static char pidfilename[MAXPATHLEN]; /* name of pid file */
98 static char linkpidfile[MAXPATHLEN]; /* name of linkname pid file */
99 char ppp_devnam[MAXPATHLEN];	/* name of PPP tty (maybe ttypx) */
100 static uid_t uid;		/* Our real user-id */
101 static int conn_running;	/* we have a [dis]connector running */
102 
103 int ttyfd;			/* Serial port file descriptor */
104 mode_t tty_mode = (mode_t)-1;	/* Original access permissions to tty */
105 int baud_rate;			/* Actual bits/second for serial device */
106 bool hungup;			/* terminal has been hung up */
107 bool privileged;		/* we're running as real uid root */
108 bool need_holdoff;		/* need holdoff period before restarting */
109 bool detached;			/* have detached from terminal */
110 struct stat devstat;		/* result of stat() on devnam */
111 bool prepass = 0;		/* doing prepass to find device name */
112 int devnam_fixed;		/* set while in options.ttyxx file */
113 volatile int status;		/* exit status for pppd */
114 int unsuccess;			/* # unsuccessful connection attempts */
115 int do_callback;		/* != 0 if we should do callback next */
116 int doing_callback;		/* != 0 if we are doing callback */
117 char *callback_script;		/* script for doing callback */
118 #ifdef HAVE_MULTILINK
119 TDB_CONTEXT *pppdb;		/* database for storing status etc. */
120 char db_key[32];
121 #endif
122 
123 /*
124  * For plug-in usage:
125  *
126  *	holdoff_hook - Can be used to change the demand-dial hold-off
127  *		time dynamically.  This is normally set by the
128  *		"holdoff" option, and is 30 seconds by default.
129  *
130  *	new_phase_hook - This is called for each change in the PPP
131  *		phase (per RFC 1661).  This can be used to log
132  *		progress.
133  *
134  *	check_options_hook - This is called before doing sys_init()
135  *		and allows the plugin to verify the selected options.
136  *
137  *	updown_script_hook - This is called with the proposed
138  *		command-line arguments for any of the
139  *		/etc/ppp/{ip,ipv6,ipx,auth}-{up,down} scripts before
140  *		fork/exec.  It can be used to add or change arguments.
141  *
142  *	device_pipe_hook - If this is set, then an extra fd (3) is
143  *		passed to the connect/disconnect script.  This extra
144  *		fd is the write side of a pipe, and the read side is
145  *		passed to this routine.  This can be used to pass
146  *		arbitrary data from the script back to pppd.
147  */
148 int (*holdoff_hook) __P((void)) = NULL;
149 int (*new_phase_hook) __P((int new, int old)) = NULL;
150 int (*check_options_hook) __P((uid_t uid)) = NULL;
151 int (*updown_script_hook) __P((const char ***argsp)) = NULL;
152 void (*device_pipe_hook) __P((int pipefd)) = NULL;
153 
154 static int fd_ppp = -1;		/* fd for talking PPP */
155 static int fd_loop;		/* fd for getting demand-dial packets */
156 static int pty_master;		/* fd for master side of pty */
157 int pty_slave = -1;		/* fd for slave side of pty */
158 static int real_ttyfd;		/* fd for actual serial port (not pty) */
159 
160 int phase;			/* where the link is at */
161 int kill_link;
162 int open_ccp_flag;
163 
164 static int waiting;		/* for input from peer or timer expiration */
165 static sigjmp_buf sigjmp;
166 
167 char **script_env;		/* Env. variable values for scripts */
168 int s_env_nalloc;		/* # words avail at script_env */
169 
170 u_char outpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for outgoing packet */
171 u_char inpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for incoming packet */
172 u_char nak_buffer[PPP_MRU];	/* where we construct a nak packet */
173 
174 static int n_children;		/* # child processes still running */
175 static bool got_sigchld;	/* set if we have received a SIGCHLD */
176 static sigset_t main_sigmask;	/* signals blocked while dispatching */
177 
178 static bool locked;		/* lock() has succeeded */
179 static bool privopen;		/* don't lock, open device as root */
180 
181 char *no_ppp_msg = "Sorry - this system lacks PPP kernel support\n";
182 
183 GIDSET_TYPE groups[NGROUPS_MAX];/* groups the user is in */
184 int ngroups;			/* How many groups valid in groups */
185 
186 static struct timeval start_time; /* Time when link was started. */
187 
188 struct pppd_stats link_stats;
189 int link_connect_time;
190 bool link_stats_valid;
191 
192 static pid_t charshunt_pid;	/* Process ID for charshunt */
193 
194 extern option_t general_options[];
195 extern option_t auth_options[];
196 
197 /*
198  * We maintain a list of child process pids and
199  * functions to call when they exit.
200  */
201 struct subprocess {
202     pid_t	pid;
203     char	*prog;
204     void	(*done) __P((void *, int));
205     void	*arg;
206     struct subprocess *next;
207 };
208 
209 static struct subprocess *children;
210 
211 /* Prototypes for procedures local to this file. */
212 
213 static void setup_signals __P((void));
214 static void create_pidfile __P((void));
215 static void create_linkpidfile __P((void));
216 static void cleanup __P((void));
217 static void close_tty __P((void));
218 static void get_input __P((void));
219 static void calltimeout __P((void));
220 static struct timeval *timeleft __P((struct timeval *));
221 static void kill_my_pg __P((int));
222 static void hup __P((int));
223 static void term __P((int));
224 static void chld __P((int));
225 static void toggle_debug __P((int));
226 static void open_ccp __P((int));
227 static void bad_signal __P((int));
228 static void holdoff_end __P((void *));
229 static int device_script __P((char *, int, int, int, char *));
230 static int reap_kids __P((int waitfor));
231 static void record_child __P((pid_t, char *, void (*) (void *, int), void *));
232 static int open_socket __P((char *));
233 static int start_charshunt __P((int, int));
234 static void charshunt_done __P((void *, int));
235 static void charshunt __P((int, int, char *));
236 static int record_write __P((FILE *, int code, u_char *buf, int nb,
237     struct timeval *));
238 static void final_reap __P((void));
239 
240 #ifdef HAVE_MULTILINK
241 static void update_db_entry __P((void));
242 static void add_db_key __P((const char *));
243 static void delete_db_key __P((const char *));
244 static void cleanup_db __P((void));
245 #endif
246 
247 int main __P((int, char *[]));
248 
249 #ifdef ultrix
250 #undef	O_NONBLOCK
251 #define	O_NONBLOCK	O_NDELAY
252 #endif
253 
254 #ifdef ULTRIX
255 #define setlogmask(x)	0
256 #endif
257 
258 /* Backward compatibility for Linux */
259 #ifndef RECMARK_TIMESTART
260 #define	RECMARK_STARTSEND	1
261 #define	RECMARK_STARTRECV	2
262 #define	RECMARK_ENDSEND		3
263 #define	RECMARK_ENDRECV		4
264 #define	RECMARK_TIMEDELTA32	5
265 #define	RECMARK_TIMEDELTA8	6
266 #define	RECMARK_TIMESTART	7
267 #endif
268 
269 /*
270  * PPP Data Link Layer "protocol" table.
271  * One entry per supported protocol.
272  * The last entry must be NULL.
273  */
274 struct protent *protocols[] = {
275     &lcp_protent,
276     &pap_protent,
277     &chap_protent,
278 #ifdef CBCP_SUPPORT
279     &cbcp_protent,
280 #endif
281     &ipcp_protent,
282 #ifdef INET6
283     &ipv6cp_protent,
284 #endif
285     &ccp_protent,
286 #ifdef IPX_CHANGE
287     &ipxcp_protent,
288 #endif
289 #ifdef AT_CHANGE
290     &atcp_protent,
291 #endif
292     NULL
293 };
294 
295 int
296 main(argc, argv)
297     int argc;
298     char *argv[];
299 {
300     int i, fdflags, t;
301     char *p, *connector;
302     struct passwd *pw;
303     struct timeval timo;
304     struct protent *protp;
305     struct stat statbuf;
306     char numbuf[16];
307 
308     ifname[0] = '\0';
309     new_phase(PHASE_INITIALIZE);
310 
311     /*
312      * Ensure that fds 0, 1, 2 are open, to /dev/null if nowhere else.
313      * This way we can close 0, 1, 2 in detach() without clobbering
314      * a fd that we are using.
315      */
316     if ((i = open(_PATH_DEVNULL, O_RDWR)) >= 0) {
317 	while (0 <= i && i <= 2)
318 	    i = dup(i);
319 	if (i >= 0)
320 	    (void) close(i);
321     }
322 
323     script_env = NULL;
324 
325     /* Initialize syslog facilities */
326     reopen_log();
327 
328     if (gethostname(hostname, MAXHOSTNAMELEN+1) < 0 ) {
329 	option_error("Couldn't get hostname: %m");
330 	exit(1);
331     }
332     hostname[MAXHOSTNAMELEN] = '\0';
333 
334     /* make sure we don't create world or group writable files. */
335     (void) umask(umask(0777) | 022);
336 
337     uid = getuid();
338     privileged = (uid == 0);
339     (void) slprintf(numbuf, sizeof(numbuf), "%d", uid);
340     script_setenv("ORIG_UID", numbuf, 0);
341 
342     ngroups = getgroups(NGROUPS_MAX, groups);
343 
344     /*
345      * Initialize magic number generator now so that protocols may
346      * use magic numbers in initialization.
347      */
348     magic_init();
349 
350     progname = *argv;
351     prepass = 0;
352     /*
353      * Initialize to the standard option set, then parse, in order, the
354      * system options file, the user's options file, the tty's options file,
355      * and the command line arguments.  At last, install the options declared
356      * by each protocol into the extra_option list.
357      */
358     for (i = 0; (protp = protocols[i]) != NULL; ++i) {
359         (*protp->init)(0);
360 	if (protp->options != NULL) {
361 	    add_options(protp->options);
362 	}
363     }
364 
365     /*
366      * Install "generic" options into the extra_options list.
367      */
368     add_options(auth_options);
369     add_options(general_options);
370 
371     /* Install any system-specific options (or remove unusable ones) */
372     sys_options();
373 
374     if (!options_from_file(_PATH_SYSOPTIONS, !privileged, 0, 1)
375 	|| !options_from_user())
376 	exit(EXIT_OPTION_ERROR);
377 
378     /* scan command line and options files to find device name */
379     prepass = 1;
380     (void) parse_args(argc-1, argv+1);
381     prepass = 0;
382 
383     /*
384      * Work out the device name, if it hasn't already been specified.
385      */
386     using_pty = notty || ptycommand != NULL || pty_socket != NULL;
387     if (!using_pty && default_device && !direct_tty) {
388 	char *p;
389 
390 	if (!isatty(0) || (p = ttyname(0)) == NULL) {
391 	    option_error("no device specified and stdin is not a tty");
392 	    exit(EXIT_OPTION_ERROR);
393 	}
394 	(void) strlcpy(devnam, p, sizeof(devnam));
395 	if (stat(devnam, &devstat) < 0)
396 	    fatal("Couldn't stat default device %s: %m", devnam);
397     }
398 
399     /*
400      * Parse the tty options file and the command line.
401      * The per-tty options file should not change
402      * ptycommand, pty_socket, notty or devnam.
403      */
404     devnam_fixed = 1;
405     if (!using_pty && !direct_tty) {
406 	if (!options_for_tty())
407 	    exit(EXIT_OPTION_ERROR);
408     }
409 
410     devnam_fixed = 0;
411     if (!parse_args(argc-1, argv+1))
412 	exit(EXIT_OPTION_ERROR);
413 
414     /*
415      * Check that we are running as root.
416      */
417     if (geteuid() != 0) {
418 	option_error("must be root to run %s, since it is not setuid-root",
419 		     argv[0]);
420 	exit(EXIT_NOT_ROOT);
421     }
422 
423     if (!ppp_available()) {
424 	option_error(no_ppp_msg);
425 	exit(EXIT_NO_KERNEL_SUPPORT);
426     }
427 
428     /*
429      * Check that the options given are valid and consistent.
430      */
431     if (!sys_check_options())
432 	exit(EXIT_OPTION_ERROR);
433     auth_check_options();
434 #ifdef HAVE_MULTILINK
435     mp_check_options();
436 #endif
437     for (i = 0; (protp = protocols[i]) != NULL; ++i)
438 	if (protp->enabled_flag && protp->check_options != NULL)
439 	    (*protp->check_options)();
440     if (demand && (connect_script == NULL)) {
441 	option_error("connect script is required for demand-dialling\n");
442 	exit(EXIT_OPTION_ERROR);
443     }
444     if (updetach && (nodetach || demand)) {
445 	option_error("updetach cannot be used with %s",
446 	    nodetach ? "nodetach" : "demand");
447 	exit(EXIT_OPTION_ERROR);
448     }
449     /* default holdoff to 0 if no connect script has been given */
450     if ((connect_script == NULL) && !holdoff_specified)
451 	holdoff = 0;
452 
453     if (using_pty || direct_tty) {
454 	if (!default_device) {
455 	    option_error("%s option precludes specifying device name",
456 			 notty? "notty": "pty");
457 	    exit(EXIT_OPTION_ERROR);
458 	}
459 	if (ptycommand != NULL && (notty || direct_tty)) {
460 	    option_error("pty option is incompatible with notty option");
461 	    exit(EXIT_OPTION_ERROR);
462 	}
463 	if (pty_socket != NULL && (ptycommand != NULL || notty ||
464 	    direct_tty)) {
465 	    option_error("socket option is incompatible with pty and notty");
466 	    exit(EXIT_OPTION_ERROR);
467 	}
468 	default_device = notty || direct_tty;
469 	lockflag = 0;
470 	modem = 0;
471 	if (default_device && log_to_fd <= 1)
472 	    log_to_fd = -1;
473     } else {
474 	/*
475 	 * If the user has specified a device which is the same as
476 	 * the one on stdin, pretend they didn't specify any.
477 	 * If the device is already open read/write on stdin,
478 	 * we assume we don't need to lock it, and we can open it as root.
479 	 */
480 	if (fstat(0, &statbuf) >= 0 && S_ISCHR(statbuf.st_mode)
481 	    && statbuf.st_rdev == devstat.st_rdev) {
482 	    default_device = 1;
483 	    fdflags = fcntl(0, F_GETFL);
484 	    if (fdflags != -1 && (fdflags & O_ACCMODE) == O_RDWR)
485 		privopen = 1;
486 	}
487     }
488     if (default_device)
489 	nodetach = 1;
490 
491     /*
492      * Don't send log messages to the serial port, it tends to
493      * confuse the peer. :-)
494      */
495     if (log_to_fd >= 0 && fstat(log_to_fd, &statbuf) >= 0
496 	&& S_ISCHR(statbuf.st_mode) && statbuf.st_rdev == devstat.st_rdev)
497 	log_to_fd = -1;
498     early_log = 0;
499 
500     if (debug)
501 	(void) setlogmask(LOG_UPTO(LOG_DEBUG));
502 
503     /*
504      * Initialize system-dependent stuff.
505      */
506     if (check_options_hook != NULL &&
507 	(*check_options_hook)(uid) == -1) {
508 	exit(EXIT_OPTION_ERROR);
509     }
510     sys_init(!devnam_info.priv && !privopen);
511 
512 #ifdef HAVE_MULTILINK
513     pppdb = tdb_open(_PATH_PPPDB, 0, 0, O_RDWR|O_CREAT, 0644);
514     if (pppdb != NULL) {
515 	(void) slprintf(db_key, sizeof(db_key), "pppd%d", getpid());
516 	update_db_entry();
517     } else {
518 	warn("Warning: couldn't open ppp database %s", _PATH_PPPDB);
519 	if (multilink) {
520 	    warn("Warning: disabling multilink");
521 	    multilink = 0;
522 	}
523     }
524 #endif
525 
526     /*
527      * Detach ourselves from the terminal, if required, and identify
528      * who is running us.  Printing to stderr stops here unless
529      * nodetach or updetach is set.
530      */
531     if (!nodetach && !updetach)
532 	detach();
533     p = getlogin();
534     if (p == NULL) {
535 	pw = getpwuid(uid);
536 	if (pw != NULL && pw->pw_name != NULL)
537 	    p = pw->pw_name;
538 	else
539 	    p = "(unknown)";
540     }
541     syslog(LOG_NOTICE, "pppd %s.%d%s started by %s, uid %d",
542 	   VERSION, PATCHLEVEL, IMPLEMENTATION, p, uid);
543     script_setenv("PPPLOGNAME", p, 0);
544 
545     if (devnam[0] != '\0')
546 	script_setenv("DEVICE", devnam, 1);
547     (void) slprintf(numbuf, sizeof(numbuf), "%d", getpid());
548     script_setenv("PPPD_PID", numbuf, 1);
549 
550     setup_signals();
551 
552     waiting = 0;
553 
554     create_linkpidfile();
555 
556     /*
557      * If we're doing dial-on-demand, set up the interface now.
558      */
559     if (demand) {
560 	/*
561 	 * Open the loopback channel and set it up to be the ppp interface.
562 	 */
563 #ifdef HAVE_MULTILINK
564 	(void) tdb_writelock(pppdb);
565 #endif
566 	set_ifunit(1);
567 	fd_loop = open_ppp_loopback();
568 #ifdef HAVE_MULTILINK
569 	(void) tdb_writeunlock(pppdb);
570 #endif
571 
572 	/*
573 	 * Configure the interface and mark it up, etc.
574 	 */
575 	demand_conf();
576     }
577 
578     new_phase(PHASE_INITIALIZED);
579     do_callback = 0;
580     for (;;) {
581 
582 	need_holdoff = 1;
583 	ttyfd = -1;
584 	real_ttyfd = -1;
585 	status = EXIT_OK;
586 	++unsuccess;
587 	doing_callback = do_callback;
588 	do_callback = 0;
589 
590 	if (demand && !doing_callback) {
591 	    /*
592 	     * Don't do anything until we see some activity.
593 	     */
594 	    kill_link = 0;
595 	    new_phase(PHASE_DORMANT);
596 	    demand_unblock();
597 	    add_fd(fd_loop);
598 	    for (;;) {
599 		if (sigsetjmp(sigjmp, 1) == 0) {
600 		    (void) sigprocmask(SIG_BLOCK, &main_sigmask, NULL);
601 		    if (kill_link || got_sigchld) {
602 			(void) sigprocmask(SIG_UNBLOCK, &main_sigmask, NULL);
603 		    } else {
604 			waiting = 1;
605 			(void) sigprocmask(SIG_UNBLOCK, &main_sigmask, NULL);
606 			wait_input(timeleft(&timo));
607 		    }
608 		}
609 		waiting = 0;
610 		calltimeout();
611 		if (kill_link) {
612 		    if (!persist)
613 			break;
614 		    kill_link = 0;
615 		}
616 		if (get_loop_output())
617 		    break;
618 		if (got_sigchld)
619 		    (void) reap_kids(0);
620 	    }
621 	    remove_fd(fd_loop);
622 	    if (kill_link && !persist)
623 		break;
624 
625 	    /*
626 	     * Now we want to bring up the link.
627 	     */
628 	    demand_block();
629 	    info("Starting link");
630 	}
631 
632 	new_phase(doing_callback ? PHASE_CALLINGBACK : PHASE_SERIALCONN);
633 
634 	/*
635 	 * Get a pty master/slave pair if the pty, notty, socket,
636 	 * or record options were specified.
637 	 */
638 	(void) strlcpy(ppp_devnam, devnam, sizeof(ppp_devnam));
639 	pty_master = -1;
640 	pty_slave = -1;
641 	if (using_pty || record_file != NULL) {
642 	    if (!get_pty(&pty_master, &pty_slave, ppp_devnam, uid)) {
643 		error("Couldn't allocate pseudo-tty");
644 		status = EXIT_FATAL_ERROR;
645 		goto fail;
646 	    }
647 	    set_up_tty(pty_slave, 1);
648 	}
649 
650 	/*
651 	 * Lock the device if we've been asked to.
652 	 */
653 	status = EXIT_LOCK_FAILED;
654 	if (lockflag && !privopen && !direct_tty) {
655 	    if (lock(devnam) < 0)
656 		goto fail;
657 	    locked = 1;
658 	}
659 
660 	/*
661 	 * Open the serial device and set it up to be the ppp interface.
662 	 * First we open it in non-blocking mode so we can set the
663 	 * various termios flags appropriately.  If we aren't dialling
664 	 * out and we want to use the modem lines, we reopen it later
665 	 * in order to wait for the carrier detect signal from the modem.
666 	 */
667 	hungup = 0;
668 	kill_link = 0;
669 	connector = doing_callback? callback_script: connect_script;
670 	if (direct_tty) {
671 	    ttyfd = 0;
672 	} else if (devnam[0] != '\0') {
673 	    for (;;) {
674 		/* If the user specified the device name, become the
675 		   user before opening it. */
676 		int err;
677 		if (!devnam_info.priv && !privopen)
678 		    (void) seteuid(uid);
679 		if ((ttyfd = sys_extra_fd()) < 0)
680 		    ttyfd = open(devnam, O_NONBLOCK | O_RDWR);
681 		err = errno;
682 		if (!devnam_info.priv && !privopen)
683 		    (void) seteuid(0);
684 		if (ttyfd >= 0)
685 		    break;
686 		errno = err;
687 		if (err != EINTR) {
688 		    error("Failed to open %s: %m", devnam);
689 		    status = EXIT_OPEN_FAILED;
690 		}
691 		if (!persist || err != EINTR)
692 		    goto fail;
693 	    }
694 	    if ((fdflags = fcntl(ttyfd, F_GETFL)) == -1
695 		|| fcntl(ttyfd, F_SETFL, fdflags & ~O_NONBLOCK) < 0)
696 		warn("Couldn't reset non-blocking mode on device: %m");
697 
698 	    /*
699 	     * Do the equivalent of `mesg n' to stop broadcast messages.
700 	     */
701 	    if (fstat(ttyfd, &statbuf) < 0
702 		|| fchmod(ttyfd, statbuf.st_mode & ~(S_IWGRP | S_IWOTH)) < 0) {
703 		warn("Couldn't restrict write permissions to %s: %m", devnam);
704 	    } else
705 		tty_mode = statbuf.st_mode;
706 
707 	    /*
708 	     * Set line speed, flow control, etc.
709 	     * If we have a non-null connection or initializer script,
710 	     * on most systems we set CLOCAL for now so that we can talk
711 	     * to the modem before carrier comes up.  But this has the
712 	     * side effect that we might miss it if CD drops before we
713 	     * get to clear CLOCAL below.  On systems where we can talk
714 	     * successfully to the modem with CLOCAL clear and CD down,
715 	     * we could clear CLOCAL at this point.
716 	     */
717 	    set_up_tty(ttyfd, ((connector != NULL && connector[0] != '\0')
718 			       || initializer != NULL));
719 	    real_ttyfd = ttyfd;
720 	}
721 
722 	/*
723 	 * If the pty, socket, notty and/or record option was specified,
724 	 * start up the character shunt now.
725 	 */
726 	status = EXIT_PTYCMD_FAILED;
727 	if (ptycommand != NULL) {
728 	    if (record_file != NULL) {
729 		int ipipe[2], opipe[2], ok;
730 
731 		if (pipe(ipipe) < 0 || pipe(opipe) < 0)
732 		    fatal("Couldn't create pipes for record option: %m");
733 		dbglog("starting charshunt for pty option");
734 		ok = device_script(ptycommand, opipe[0], ipipe[1], 1,
735 		    "record") == 0 && start_charshunt(ipipe[0], opipe[1]);
736 		(void) close(ipipe[0]);
737 		(void) close(ipipe[1]);
738 		(void) close(opipe[0]);
739 		(void) close(opipe[1]);
740 		if (!ok)
741 		    goto fail;
742 	    } else {
743 		if (device_script(ptycommand, pty_master, pty_master, 1,
744 		    "pty") < 0)
745 		    goto fail;
746 		ttyfd = pty_slave;
747 		(void) close(pty_master);
748 		pty_master = -1;
749 	    }
750 	} else if (pty_socket != NULL) {
751 	    int fd = open_socket(pty_socket);
752 	    if (fd < 0)
753 		goto fail;
754 	    dbglog("starting charshunt for socket option");
755 	    if (!start_charshunt(fd, fd))
756 		goto fail;
757 	} else if (notty) {
758 	    dbglog("starting charshunt for notty option");
759 	    if (!start_charshunt(0, 1))
760 		goto fail;
761 	} else if (record_file != NULL) {
762 	    dbglog("starting charshunt for record option");
763 	    if (!start_charshunt(ttyfd, ttyfd))
764 		goto fail;
765 	}
766 
767 	/* run connection script */
768 	if (((connector != NULL) && (connector[0] != '\0')) || initializer) {
769 	    if (real_ttyfd != -1) {
770 		/* XXX do this if doing_callback == CALLBACK_DIALIN? */
771 		if (!default_device && modem && !direct_tty) {
772 		    setdtr(real_ttyfd, 0);	/* in case modem is off hook */
773 		    (void) sleep(1);
774 		    setdtr(real_ttyfd, 1);
775 		}
776 	    }
777 
778 	    if ((initializer != NULL) && (initializer[0] != '\0')) {
779 		if (device_script(initializer, ttyfd, ttyfd, 0, "init") < 0) {
780 		    error("Initializer script failed");
781 		    status = EXIT_INIT_FAILED;
782 		    goto fail;
783 		}
784 		if (kill_link)
785 		    goto disconnect;
786 
787 		info("Serial port initialized.");
788 	    }
789 
790 	    if ((connector != NULL) && (connector[0] != '\0')) {
791 		if (device_script(connector, ttyfd, ttyfd, 0, "connect") < 0) {
792 		    error("Connect script failed");
793 		    status = EXIT_CONNECT_FAILED;
794 		    goto fail;
795 		}
796 		if (kill_link)
797 		    goto disconnect;
798 
799 		info("Serial connection established.");
800 	    }
801 
802 	    /*
803 	     * Clear CLOCAL if modem option -- we now have carrier
804 	     * established, and we should respect loss of carrier.
805 	     */
806 	    if (real_ttyfd != -1)
807 		set_up_tty(real_ttyfd, 0);
808 
809 	    if (doing_callback == CALLBACK_DIALIN)
810 		connector = NULL;
811 	}
812 
813 	/* reopen tty if necessary to wait for carrier */
814 	if (connector == NULL && modem && devnam[0] != '\0' && !direct_tty) {
815 	    for (;;) {
816 		if ((i = open(devnam, O_RDWR)) >= 0)
817 		    break;
818 		if (errno != EINTR) {
819 		    error("Failed to reopen %s: %m", devnam);
820 		    status = EXIT_OPEN_FAILED;
821 		}
822 		if (!persist || errno != EINTR || hungup || kill_link)
823 		    goto fail;
824 	    }
825 	    (void) close(i);
826 	}
827 
828 	(void) slprintf(numbuf, sizeof(numbuf), "%d", baud_rate);
829 	script_setenv("SPEED", numbuf, 0);
830 
831 	/* run welcome script, if any */
832 	if ((welcomer != NULL) && (welcomer[0] != '\0')) {
833 	    if (device_script(welcomer, ttyfd, ttyfd, 0, "welcome") < 0)
834 		warn("Welcome script failed");
835 	}
836 
837 	/* set up the serial device as a ppp interface */
838 #ifdef HAVE_MULTILINK
839 	(void) tdb_writelock(pppdb);
840 #endif
841 	fd_ppp = establish_ppp(ttyfd);
842 	if (fd_ppp < 0) {
843 #ifdef HAVE_MULTILINK
844 	    (void) tdb_writeunlock(pppdb);
845 #endif
846 	    status = EXIT_FATAL_ERROR;
847 	    goto disconnect;
848 	}
849 
850 	if (!demand && ifunit >= 0)
851 	    set_ifunit(1);
852 #ifdef HAVE_MULTILINK
853 	(void) tdb_writeunlock(pppdb);
854 #endif
855 
856 	/*
857 	 * Start opening the connection and wait for
858 	 * incoming events (reply, timeout, etc.).
859 	 */
860 	notice("Connect: %s <--> %s", ifname, ppp_devnam);
861 	(void) gettimeofday(&start_time, NULL);
862 	link_stats_valid = 0;
863 	script_unsetenv("CONNECT_TIME");
864 	script_unsetenv("BYTES_SENT");
865 	script_unsetenv("BYTES_RCVD");
866 	lcp_lowerup(0);
867 
868 	/* Mostly for accounting purposes */
869 	new_phase(PHASE_CONNECTED);
870 
871 	/*
872 	 * If we are initiating this connection, wait for a short
873 	 * time for something from the peer.  This can avoid bouncing
874 	 * our packets off his tty before he has it set up.
875 	 */
876 	add_fd(fd_ppp);
877 	if (connect_delay != 0 && (connector != NULL || ptycommand != NULL)) {
878 	    struct timeval t;
879 	    t.tv_sec = connect_delay / 1000;
880 	    t.tv_usec = connect_delay % 1000;
881 	    wait_input(&t);
882 	}
883 
884 	lcp_open(0);		/* Start protocol */
885 	open_ccp_flag = 0;
886 	status = EXIT_NEGOTIATION_FAILED;
887 	new_phase(PHASE_ESTABLISH);
888 	while (phase != PHASE_DEAD) {
889 	    if (sigsetjmp(sigjmp, 1) == 0) {
890 		(void) sigprocmask(SIG_BLOCK, &main_sigmask, NULL);
891 		if (kill_link || open_ccp_flag || got_sigchld) {
892 		    (void) sigprocmask(SIG_UNBLOCK, &main_sigmask, NULL);
893 		} else {
894 		    waiting = 1;
895 		    (void) sigprocmask(SIG_UNBLOCK, &main_sigmask, NULL);
896 		    wait_input(timeleft(&timo));
897 		}
898 	    }
899 	    waiting = 0;
900 	    calltimeout();
901 	    get_input();
902 	    if (kill_link) {
903 		lcp_close(0, "User request");
904 		kill_link = 0;
905 	    }
906 	    if (open_ccp_flag) {
907 		if (phase == PHASE_NETWORK || phase == PHASE_RUNNING) {
908 		    /* Uncloak ourselves. */
909 		    ccp_fsm[0].flags &= ~OPT_SILENT;
910 		    (*ccp_protent.open)(0);
911 		}
912 		open_ccp_flag = 0;
913 	    }
914 	    if (got_sigchld)
915 		(void) reap_kids(0);	/* Don't leave dead kids lying around */
916 	}
917 
918 	/*
919 	 * Print connect time and statistics.
920 	 */
921 	if (link_stats_valid) {
922 	    int t = (link_connect_time + 5) / 6;    /* 1/10ths of minutes */
923 	    info("Connect time %d.%d minutes.", t/10, t%10);
924 	    info("Sent %" PPP_COUNTER_F " bytes (%" PPP_COUNTER_F
925 		" packets), received %" PPP_COUNTER_F " bytes (%" PPP_COUNTER_F
926 		" packets).",
927 		 link_stats.bytes_out, link_stats.pkts_out,
928 		 link_stats.bytes_in, link_stats.pkts_in);
929 	}
930 
931 	/*
932 	 * Delete pid file before disestablishing ppp.  Otherwise it
933 	 * can happen that another pppd gets the same unit and then
934 	 * we delete its pid file.
935 	 */
936 	if (!demand) {
937 	    if (pidfilename[0] != '\0'
938 		&& unlink(pidfilename) < 0 && errno != ENOENT)
939 		warn("unable to delete pid file %s: %m", pidfilename);
940 	    pidfilename[0] = '\0';
941 	}
942 
943 	/*
944 	 * If we may want to bring the link up again, transfer
945 	 * the ppp unit back to the loopback.  Set the
946 	 * real serial device back to its normal mode of operation.
947 	 */
948 	remove_fd(fd_ppp);
949 	clean_check();
950 	if (demand)
951 	    restore_loop();
952 	disestablish_ppp(ttyfd);
953 	fd_ppp = -1;
954 	if (!hungup)
955 	    lcp_lowerdown(0);
956 	if (!demand)
957 	    script_unsetenv("IFNAME");
958 
959 	/*
960 	 * Run disconnector script, if requested.
961 	 * XXX we may not be able to do this if the line has hung up!
962 	 */
963     disconnect:
964 	if ((disconnect_script != NULL) && (disconnect_script[0] != '\0') &&
965 	    !hungup) {
966 	    new_phase(PHASE_DISCONNECT);
967 	    if (real_ttyfd >= 0)
968 		set_up_tty(real_ttyfd, 1);
969 	    if (device_script(disconnect_script, ttyfd, ttyfd, 0,
970 		"disconnect") < 0) {
971 		warn("disconnect script failed");
972 	    } else {
973 		info("Serial link disconnected.");
974 	    }
975 	}
976 
977     fail:
978 	if (pty_master >= 0)
979 	    (void) close(pty_master);
980 	if (pty_slave >= 0) {
981 	    (void) close(pty_slave);
982 	    pty_slave = -1;
983 	}
984 	if (real_ttyfd >= 0)
985 	    close_tty();
986 	if (locked) {
987 	    locked = 0;
988 	    unlock();
989 	}
990 
991 	if (!demand) {
992 	    if (pidfilename[0] != '\0'
993 		&& unlink(pidfilename) < 0 && errno != ENOENT)
994 		warn("unable to delete pid file %s: %m", pidfilename);
995 	    pidfilename[0] = '\0';
996 	}
997 
998 	if (!persist || (maxfail > 0 && unsuccess >= maxfail))
999 	    break;
1000 
1001 	kill_link = 0;
1002 	if (demand)
1003 	    demand_discard();
1004 	t = need_holdoff? holdoff: 0;
1005 	if (holdoff_hook != NULL)
1006 	    t = (*holdoff_hook)();
1007 	if (t > 0) {
1008 	    new_phase(PHASE_HOLDOFF);
1009 	    TIMEOUT(holdoff_end, NULL, t);
1010 	    do {
1011 		if (sigsetjmp(sigjmp, 1) == 0) {
1012 		    (void) sigprocmask(SIG_BLOCK, &main_sigmask, NULL);
1013 		    if (kill_link || got_sigchld) {
1014 			(void) sigprocmask(SIG_UNBLOCK, &main_sigmask, NULL);
1015 		    } else {
1016 			waiting = 1;
1017 			(void) sigprocmask(SIG_UNBLOCK, &main_sigmask, NULL);
1018 			wait_input(timeleft(&timo));
1019 		    }
1020 		}
1021 		waiting = 0;
1022 		calltimeout();
1023 		if (kill_link) {
1024 		    kill_link = 0;
1025 		    new_phase(PHASE_DORMANT); /* allow signal to end holdoff */
1026 		}
1027 		if (got_sigchld)
1028 		    (void) reap_kids(0);
1029 	    } while (phase == PHASE_HOLDOFF);
1030 	    if (!persist)
1031 		break;
1032 	}
1033     }
1034 
1035     /* Wait for scripts to finish */
1036     final_reap();
1037 
1038     die(status);
1039     return (0);
1040 }
1041 
1042 /*
1043  * setup_signals - initialize signal handling.
1044  */
1045 static void
1046 setup_signals()
1047 {
1048     struct sigaction sa;
1049 
1050     /*
1051      * Compute mask of all interesting signals and install signal handlers
1052      * for each.  Only one signal handler may be active at a time.  Therefore,
1053      * all other signals should be masked when any handler is executing.
1054      */
1055     (void) sigemptyset(&main_sigmask);
1056     (void) sigaddset(&main_sigmask, SIGHUP);
1057     (void) sigaddset(&main_sigmask, SIGINT);
1058     (void) sigaddset(&main_sigmask, SIGTERM);
1059     (void) sigaddset(&main_sigmask, SIGCHLD);
1060     (void) sigaddset(&main_sigmask, SIGUSR2);
1061 
1062 #define SIGNAL(s, handler)	if (1) { \
1063 	sa.sa_handler = handler; \
1064 	if (sigaction(s, &sa, NULL) < 0) \
1065 	    fatal("Couldn't establish signal handler (%d): %m", s); \
1066     } else ((void)0)
1067 
1068     sa.sa_mask = main_sigmask;
1069     sa.sa_flags = 0;
1070 /*CONSTANTCONDITION*/ SIGNAL(SIGHUP, hup);		/* Hangup */
1071 /*CONSTANTCONDITION*/ SIGNAL(SIGINT, term);		/* Interrupt */
1072 /*CONSTANTCONDITION*/ SIGNAL(SIGTERM, term);		/* Terminate */
1073 /*CONSTANTCONDITION*/ SIGNAL(SIGCHLD, chld);
1074 
1075 /*CONSTANTCONDITION*/ SIGNAL(SIGUSR1, toggle_debug);	/* Toggle debug flag */
1076 /*CONSTANTCONDITION*/ SIGNAL(SIGUSR2, open_ccp);	/* Reopen CCP */
1077 
1078     /*
1079      * Install a handler for other signals which would otherwise
1080      * cause pppd to exit without cleaning up.
1081      */
1082 /*CONSTANTCONDITION*/ SIGNAL(SIGABRT, bad_signal);
1083 /*CONSTANTCONDITION*/ SIGNAL(SIGALRM, bad_signal);
1084 /*CONSTANTCONDITION*/ SIGNAL(SIGFPE, bad_signal);
1085 /*CONSTANTCONDITION*/ SIGNAL(SIGILL, bad_signal);
1086 /*CONSTANTCONDITION*/ SIGNAL(SIGPIPE, bad_signal);
1087 /*CONSTANTCONDITION*/ SIGNAL(SIGQUIT, bad_signal);
1088 #ifndef DEBUG
1089 /*CONSTANTCONDITION*/ SIGNAL(SIGSEGV, bad_signal);
1090 #endif
1091 #ifdef SIGBUS
1092 /*CONSTANTCONDITION*/ SIGNAL(SIGBUS, bad_signal);
1093 #endif
1094 #ifdef SIGEMT
1095 /*CONSTANTCONDITION*/ SIGNAL(SIGEMT, bad_signal);
1096 #endif
1097 #ifdef SIGPOLL
1098 /*CONSTANTCONDITION*/ SIGNAL(SIGPOLL, bad_signal);
1099 #endif
1100 #ifdef SIGPROF
1101 /*CONSTANTCONDITION*/ SIGNAL(SIGPROF, bad_signal);
1102 #endif
1103 #ifdef SIGSYS
1104 /*CONSTANTCONDITION*/ SIGNAL(SIGSYS, bad_signal);
1105 #endif
1106 #ifdef SIGTRAP
1107 /*CONSTANTCONDITION*/ SIGNAL(SIGTRAP, bad_signal);
1108 #endif
1109 #ifdef SIGVTALRM
1110 /*CONSTANTCONDITION*/ SIGNAL(SIGVTALRM, bad_signal);
1111 #endif
1112 #ifdef SIGXCPU
1113 /*CONSTANTCONDITION*/ SIGNAL(SIGXCPU, bad_signal);
1114 #endif
1115 #ifdef SIGXFSZ
1116 /*CONSTANTCONDITION*/ SIGNAL(SIGXFSZ, bad_signal);
1117 #endif
1118 
1119     /*
1120      * Apparently we can get a SIGPIPE when we call syslog, if
1121      * syslogd has died and been restarted.  Ignoring it seems
1122      * be sufficient.
1123      */
1124     (void) signal(SIGPIPE, SIG_IGN);
1125 }
1126 
1127 /*
1128  * set_ifunit - do things we need to do once we know which ppp
1129  * unit we are using.
1130  */
1131 void
1132 set_ifunit(iskey)
1133     int iskey;
1134 {
1135     sys_ifname();
1136     info("Using interface %s", ifname);
1137     script_setenv("IFNAME", ifname, iskey);
1138     if (iskey) {
1139 	create_pidfile();	/* write pid to file */
1140 	create_linkpidfile();
1141     }
1142 }
1143 
1144 /*
1145  * detach - detach us from the controlling terminal.
1146  */
1147 void
1148 detach()
1149 {
1150     pid_t pid;
1151     char numbuf[16];
1152 
1153     if (detached)
1154 	return;
1155     if ((pid = fork()) == (pid_t)-1) {
1156 	error("Couldn't detach (fork failed: %m)");
1157 	die(1);			/* or just return? */
1158     }
1159     if (pid != (pid_t)0) {
1160 	/* parent */
1161 	if (locked)
1162 	    (void) relock(pid);
1163 	exit(0);		/* parent dies */
1164     }
1165     (void) setsid();
1166 	/*
1167 	 * Fork again to relinquish session leadership. This is needed
1168 	 * to prevent the daemon from acquiring controlling terminal.
1169 	 */
1170     if ((pid = fork()) == (pid_t)-1) {
1171 	error("Couldn't detach (second fork failed: %m)");
1172 	die(1);			/* or just return? */
1173     }
1174     if (pid != (pid_t)0) {
1175 	/* parent */
1176 	if (locked)
1177 	    (void) relock(pid);
1178 	exit(0);		/* parent dies */
1179     }
1180     (void) chdir("/");
1181     (void) close(0);
1182     (void) close(1);
1183     (void) close(2);
1184     detached = 1;
1185     if (!log_to_file && !log_to_specific_fd)
1186 	log_to_fd = -1;
1187     /* update pid files if they have been written already */
1188     if (pidfilename[0] != '\0')
1189 	create_pidfile();
1190     if (linkpidfile[0] != '\0')
1191 	create_linkpidfile();
1192     (void) slprintf(numbuf, sizeof(numbuf), "%d", getpid());
1193     script_setenv("PPPD_PID", numbuf, 1);
1194 }
1195 
1196 /*
1197  * reopen_log - (re)open our connection to syslog.
1198  */
1199 void
1200 reopen_log()
1201 {
1202 #ifdef ULTRIX
1203     openlog("pppd", LOG_PID);
1204 #else
1205     openlog("pppd", LOG_PID | LOG_NDELAY, LOG_PPP);
1206     (void) setlogmask(LOG_UPTO(LOG_INFO));
1207 #endif
1208 }
1209 
1210 /*
1211  * Create a file containing our process ID.
1212  */
1213 static void
1214 create_pidfile()
1215 {
1216     FILE *pidfile;
1217 
1218     (void) slprintf(pidfilename, sizeof(pidfilename), "%s%s.pid",
1219 	     _PATH_VARRUN, ifname);
1220     if ((pidfile = fopen(pidfilename, "w")) != NULL) {
1221 	(void) fprintf(pidfile, "%u\n", (unsigned)getpid());
1222 	(void) fclose(pidfile);
1223     } else {
1224 	error("Failed to create pid file %s: %m", pidfilename);
1225 	pidfilename[0] = '\0';
1226     }
1227 }
1228 
1229 static void
1230 create_linkpidfile()
1231 {
1232     FILE *pidfile;
1233 
1234     if (linkname[0] == '\0')
1235 	return;
1236     script_setenv("LINKNAME", linkname, 1);
1237     (void) slprintf(linkpidfile, sizeof(linkpidfile), "%sppp-%s.pid",
1238 	     _PATH_VARRUN, linkname);
1239     if ((pidfile = fopen(linkpidfile, "w")) != NULL) {
1240 	(void) fprintf(pidfile, "%u\n", (unsigned)getpid());
1241 	if (ifname[0] != '\0')
1242 	    (void) fprintf(pidfile, "%s\n", ifname);
1243 	(void) fclose(pidfile);
1244     } else {
1245 	error("Failed to create pid file %s: %m", linkpidfile);
1246 	linkpidfile[0] = '\0';
1247     }
1248 }
1249 
1250 /*
1251  * holdoff_end - called via a timeout when the holdoff period ends.
1252  */
1253 /*ARGSUSED*/
1254 static void
1255 holdoff_end(arg)
1256     void *arg;
1257 {
1258     new_phase(PHASE_DORMANT);
1259 }
1260 
1261 /* List of protocol names, to make our messages a little more informative. */
1262 struct protocol_list {
1263     u_short	proto;
1264     const char	*name;
1265 } protocol_list[] = {
1266     { 0x21,	"IP" },
1267     { 0x23,	"OSI Network Layer" },
1268     { 0x25,	"Xerox NS IDP" },
1269     { 0x27,	"DECnet Phase IV" },
1270     { 0x29,	"Appletalk" },
1271     { 0x2b,	"Novell IPX" },
1272     { 0x2d,	"VJ compressed TCP/IP" },
1273     { 0x2f,	"VJ uncompressed TCP/IP" },
1274     { 0x31,	"Bridging PDU" },
1275     { 0x33,	"Stream Protocol ST-II" },
1276     { 0x35,	"Banyan Vines" },
1277     { 0x37,	"Old VJ compressed TCP/IP" },
1278     { 0x39,	"AppleTalk EDDP" },
1279     { 0x3b,	"AppleTalk SmartBuffered" },
1280     { 0x3d,	"Multilink" },
1281     { 0x3f,	"NetBIOS Frame" },
1282     { 0x41,	"Cisco LAN Extension" },
1283     { 0x43,	"Ascom Timeplex" },
1284     { 0x45,	"Fujitsu Link Backup and Load Balancing (LBLB)" },
1285     { 0x47,	"DCA Remote Lan" },
1286     { 0x49,	"Serial Data Transport Protocol (PPP-SDTP)" },
1287     { 0x4b,	"SNA over 802.2" },
1288     { 0x4d,	"SNA" },
1289     { 0x4f,	"IP6 Header Compression" },
1290     { 0x51,	"KNX Bridging" },
1291     { 0x53,	"Encrypted" },
1292     { 0x55,	"per-link encrypted" },
1293     { 0x57,	"IPv6" },
1294     { 0x59,	"PPP Muxing" },
1295     { 0x6f,	"Stampede Bridging" },
1296     { 0x73,	"MP+" },
1297     { 0xc1,	"STMF" },
1298     { 0xfb,	"per-link compressed" },
1299     { 0xfd,	"compressed datagram" },
1300     { 0x0201,	"802.1d Hello Packets" },
1301     { 0x0203,	"IBM Source Routing BPDU" },
1302     { 0x0205,	"DEC LANBridge100 Spanning Tree" },
1303     { 0x0207,	"Cisco Discovery Protocol" },
1304     { 0x0231,	"Luxcom" },
1305     { 0x0233,	"Sigma Network Systems" },
1306     { 0x0235,	"Apple Client Server Protocol" },
1307     { 0x0281,	"MPLS Unicast" },
1308     { 0x0283,	"MPLS Multicast" },
1309     { 0x0285,	"IEEE p1284.4" },
1310     { 0x0287,	"ETSI TETRA TNP1" },
1311     { 0x4021,	"Stacker LZS" },
1312     { 0x8021,	"Internet Protocol Control Protocol" },
1313     { 0x8023,	"OSI Network Layer Control Protocol" },
1314     { 0x8025,	"Xerox NS IDP Control Protocol" },
1315     { 0x8027,	"DECnet Phase IV Control Protocol" },
1316     { 0x8029,	"Appletalk Control Protocol" },
1317     { 0x802b,	"Novell IPX Control Protocol" },
1318     { 0x8031,	"Bridging Control Protocol" },
1319     { 0x8033,	"Stream Protocol Control Protocol" },
1320     { 0x8035,	"Banyan Vines Control Protocol" },
1321     { 0x803f,	"NetBIOS Frames Control Protocol" },
1322     { 0x8041,	"Cisco LAN Extension Control Protocol" },
1323     { 0x8043,	"Ascom Timeplex Control Protocol" },
1324     { 0x8045,	"Fujitsu LBLB Control Protocol" },
1325     { 0x8047,	"DCA Remote Lan Network Control Protocol (RLNCP)" },
1326     { 0x8049,	"Serial Data Control Protocol (PPP-SDCP)" },
1327     { 0x804b,	"SNA over 802.2 Control Protocol" },
1328     { 0x804d,	"SNA Control Protocol" },
1329     { 0x8051,	"KNX Bridging Control Protocol" },
1330     { 0x8053,	"Encryption Control Protocol" },
1331     { 0x8055,	"Per-link Encryption Control Protocol" },
1332     { 0x8057,	"IPv6 Control Protocol" },
1333     { 0x806f,	"Stampede Bridging Control Protocol" },
1334     { 0x80c1,	"STMF Control Protocol" },
1335     { 0x80fb,	"Per-link Compression Control Protocol" },
1336     { 0x80fd,	"Compression Control Protocol" },
1337     { 0x8207,	"Cisco Discovery Control Protocol" },
1338     { 0x8235,	"Apple Client Server Control Protocol" },
1339     { 0x8281,	"MPLS Control Protocol" },
1340     { 0x8287,	"ETSI TETRA TNP1 Control Protocol" },
1341     { 0xc021,	"Link Control Protocol" },
1342     { 0xc023,	"Password Authentication Protocol" },
1343     { 0xc025,	"Link Quality Report" },
1344     { 0xc027,	"Shiva Password Authentication Protocol" },
1345     { 0xc029,	"CallBack Control Protocol (CBCP)" },
1346     { 0xc02b,	"Bandwidth Allocation Control Protocol" },
1347     { 0xc02d,	"BAP" },
1348     { 0xc081,	"Container Control Protocol" },
1349     { 0xc223,	"Challenge Handshake Authentication Protocol" },
1350     { 0xc227,	"Extensible Authentication Protocol" },
1351     { 0xc281,	"Funk Proprietary Authentication Protocol" },
1352     { 0,	NULL },
1353 };
1354 
1355 /*
1356  * protocol_name - find a name for a PPP protocol.
1357  */
1358 const char *
1359 protocol_name(proto)
1360     int proto;
1361 {
1362     struct protocol_list *lp;
1363 
1364     for (lp = protocol_list; lp->proto != 0; ++lp)
1365 	if (proto == lp->proto)
1366 	    return (lp->name);
1367     return (NULL);
1368 }
1369 
1370 static const char *phase_names[] = { PHASE__NAMES };
1371 
1372 const char *
1373 phase_name(pval)
1374     int pval;
1375 {
1376     static char buf[32];
1377 
1378     if (pval < 0 || pval >= Dim(phase_names)) {
1379 	(void) slprintf(buf, sizeof (buf), "unknown %d", pval);
1380 	return ((const char *)buf);
1381     }
1382     return (phase_names[pval]);
1383 }
1384 
1385 /*
1386  * get_input - called when incoming data is available.
1387  */
1388 static void
1389 get_input()
1390 {
1391     int len, i;
1392     u_char *p;
1393     u_short protocol;
1394     struct protent *protp;
1395     const char *pname;
1396 
1397     p = inpacket_buf;	/* point to beginning of packet buffer */
1398 
1399     len = read_packet(inpacket_buf);
1400     if (len < 0)
1401 	return;
1402 
1403     if (len == 0) {
1404 	notice("Modem hangup");
1405 	hungup = 1;
1406 	status = EXIT_HANGUP;
1407 	lcp_lowerdown(0);	/* serial link is no longer available */
1408 	link_terminated(0);
1409 	return;
1410     }
1411 
1412     if (debug /*&& (debugflags & DBG_INPACKET)*/)
1413 	dbglog("rcvd %P", p, len);
1414 
1415     if (len < PPP_HDRLEN) {
1416 	dbglog("Discarded short packet (%d < %d)", len, PPP_HDRLEN);
1417 	return;
1418     }
1419 
1420     p += 2;				/* Skip address and control */
1421     GETSHORT(protocol, p);
1422     len -= PPP_HDRLEN;
1423 
1424     pname = debug ? NULL : protocol_name(protocol);
1425 
1426     /*
1427      * Toss all non-LCP packets unless LCP is in Opened state and
1428      * discard non-authentication protocols if we're not yet
1429      * authenticated.
1430      */
1431     if ((protocol != PPP_LCP &&
1432 	(phase < PHASE_AUTHENTICATE || phase > PHASE_RUNNING)) ||
1433 	(phase <= PHASE_AUTHENTICATE &&
1434 	    !(protocol == PPP_LCP || protocol == PPP_LQR ||
1435 		protocol == PPP_PAP || protocol == PPP_CHAP))) {
1436 	    if (pname == NULL)
1437 		    dbglog("Discarded proto 0x%x in %s phase",
1438 			protocol, phase_name(phase));
1439 	    else
1440 		    dbglog("Discarded %s (0x%x) in %s phase",
1441 			pname, protocol, phase_name(phase));
1442 	return;
1443     }
1444 
1445     /*
1446      * Upcall the proper protocol input routine.
1447      */
1448     for (i = 0; (protp = protocols[i]) != NULL; ++i) {
1449 	if (protp->protocol == protocol && protp->enabled_flag) {
1450 	    (*protp->input)(0, p, len);
1451 	    return;
1452 	}
1453         if (protocol == (protp->protocol & ~0x8000) && protp->enabled_flag
1454 	    && protp->datainput != NULL) {
1455 	    (*protp->datainput)(0, p, len);
1456 	    return;
1457 	}
1458     }
1459 
1460     if (debug) {
1461 	if (pname != NULL)
1462 	    warn("Unsupported protocol '%s' (0x%x) received", pname, protocol);
1463 	else
1464 	    warn("Unsupported protocol 0x%x received", protocol);
1465     }
1466     lcp_sprotrej(0, p - PPP_HDRLEN, len + PPP_HDRLEN);
1467 }
1468 
1469 /*
1470  * new_phase - signal the start of a new phase of pppd's operation.
1471  */
1472 void
1473 new_phase(p)
1474     int p;
1475 {
1476     if (new_phase_hook != NULL)
1477 	(*new_phase_hook)(p, phase);
1478     phase = p;
1479 }
1480 
1481 /*
1482  * die - clean up state and exit with the specified status.
1483  */
1484 void
1485 die(status)
1486     int status;
1487 {
1488     cleanup();
1489     if (phase != PHASE_EXIT) {
1490 	syslog(LOG_INFO, "Exit.");
1491 	new_phase(PHASE_EXIT);
1492     }
1493     exit(status);
1494 }
1495 
1496 /*
1497  * cleanup - restore anything which needs to be restored before we exit
1498  */
1499 static void
1500 cleanup()
1501 {
1502     sys_cleanup();  /* XXX: Need to check if this is okay after close_tty */
1503 
1504     if (fd_ppp >= 0) {
1505 	fd_ppp = -1;
1506 	disestablish_ppp(ttyfd);
1507     }
1508     if (real_ttyfd >= 0)
1509 	close_tty();
1510 
1511     if (pidfilename[0] != '\0' && unlink(pidfilename) < 0 && errno != ENOENT)
1512 	warn("unable to delete pid file %s: %m", pidfilename);
1513     pidfilename[0] = '\0';
1514     if (linkpidfile[0] != '\0' && unlink(linkpidfile) < 0 && errno != ENOENT)
1515 	warn("unable to delete pid file %s: %m", linkpidfile);
1516     linkpidfile[0] = '\0';
1517 
1518     if (locked) {
1519 	locked = 0;
1520 	unlock();
1521     }
1522 
1523 #ifdef HAVE_MULTILINK
1524     if (pppdb != NULL) {
1525 	cleanup_db();
1526 	pppdb = NULL;
1527     }
1528 #endif
1529 }
1530 
1531 /*
1532  * close_tty - restore the terminal device and close it.
1533  */
1534 static void
1535 close_tty()
1536 {
1537     int fd = real_ttyfd;
1538 
1539     real_ttyfd = -1;
1540 
1541     /* drop dtr to hang up */
1542     if (!default_device && modem) {
1543 	setdtr(fd, 0);
1544 	/*
1545 	 * This sleep is in case the serial port has CLOCAL set by default,
1546 	 * and consequently will reassert DTR when we close the device.
1547 	 */
1548 	(void) sleep(1);
1549     }
1550 
1551     restore_tty(fd);
1552 
1553     if (tty_mode != (mode_t) -1) {
1554 	if (fchmod(fd, tty_mode) != 0) {
1555 	    /* XXX if devnam is a symlink, this will change the link */
1556 	    if (chmod(devnam, tty_mode) != 0) {
1557 		error("Unable to chmod file %s: %m", devnam);
1558 	    }
1559 	}
1560     }
1561 
1562     (void) close(fd);
1563 }
1564 
1565 /*
1566  * update_link_stats - get stats at link termination.
1567  */
1568 void
1569 update_link_stats(u)
1570     int u;
1571 {
1572     struct timeval now;
1573     char numbuf[32];
1574 
1575     if (gettimeofday(&now, NULL) >= 0) {
1576 	link_connect_time = now.tv_sec - start_time.tv_sec;
1577 	(void) slprintf(numbuf, sizeof(numbuf), "%d", link_connect_time);
1578 	script_setenv("CONNECT_TIME", numbuf, 0);
1579     } else {
1580 	link_connect_time = 0;
1581     }
1582 
1583     if (get_ppp_stats(u, &link_stats)) {
1584 	(void) slprintf(numbuf, sizeof(numbuf), "%" PPP_COUNTER_F,
1585 	    link_stats.bytes_out);
1586 	script_setenv("BYTES_SENT", numbuf, 0);
1587 	(void) slprintf(numbuf, sizeof(numbuf), "%" PPP_COUNTER_F,
1588 	    link_stats.bytes_in);
1589 	script_setenv("BYTES_RCVD", numbuf, 0);
1590 	(void) slprintf(numbuf, sizeof(numbuf), "%" PPP_COUNTER_F,
1591 	    link_stats.pkts_in);
1592 	script_setenv("PKTS_RCVD", numbuf, 0);
1593 	(void) slprintf(numbuf, sizeof(numbuf), "%" PPP_COUNTER_F,
1594 	    link_stats.pkts_out);
1595 	script_setenv("PKTS_SENT", numbuf, 0);
1596 	link_stats_valid = 1;
1597     }
1598 }
1599 
1600 
1601 struct	callout {
1602     struct timeval	c_time;		/* time at which to call routine */
1603     void		*c_arg;		/* argument to routine */
1604     void		(*c_func) __P((void *)); /* routine */
1605     struct		callout *c_next;
1606 };
1607 
1608 static struct callout *callout = NULL;	/* Callout list */
1609 static struct timeval timenow;		/* Current time */
1610 
1611 /*
1612  * timeout - Schedule a timeout.
1613  *
1614  * Note that this timeout takes the number of seconds, NOT hz (as in
1615  * the kernel).
1616  */
1617 void
1618 timeout(func, arg, time)
1619     void (*func) __P((void *));
1620     void *arg;
1621     int time;
1622 {
1623     struct callout *newp, *p, **pp;
1624 
1625     MAINDEBUG(("Timeout %p:%p in %d seconds.", func, arg, time));
1626 
1627     /*
1628      * Allocate timeout.
1629      */
1630     if ((newp = (struct callout *) malloc(sizeof(struct callout))) == NULL)
1631 	novm("callout structure for timeout.");
1632     newp->c_arg = arg;
1633     newp->c_func = func;
1634     (void) gettimeofday(&timenow, NULL);
1635     newp->c_time.tv_sec = timenow.tv_sec + time;
1636     newp->c_time.tv_usec = timenow.tv_usec;
1637 
1638     /*
1639      * Find correct place and link it in.
1640      */
1641     for (pp = &callout; (p = *pp) != NULL; pp = &p->c_next)
1642 	if (newp->c_time.tv_sec < p->c_time.tv_sec
1643 	    || (newp->c_time.tv_sec == p->c_time.tv_sec
1644 		&& newp->c_time.tv_usec < p->c_time.tv_usec))
1645 	    break;
1646     newp->c_next = p;
1647     *pp = newp;
1648 }
1649 
1650 
1651 /*
1652  * untimeout - Unschedule a timeout.
1653  */
1654 void
1655 untimeout(func, arg)
1656     void (*func) __P((void *));
1657     void *arg;
1658 {
1659     struct callout **copp, *freep;
1660 
1661     MAINDEBUG(("Untimeout %p:%p.", func, arg));
1662 
1663     /*
1664      * Find first matching timeout and remove it from the list.
1665      */
1666     for (copp = &callout; (freep = *copp) != NULL; copp = &freep->c_next)
1667 	if (freep->c_func == func && freep->c_arg == arg) {
1668 	    *copp = freep->c_next;
1669 	    free((char *) freep);
1670 	    break;
1671 	}
1672 }
1673 
1674 
1675 /*
1676  * calltimeout - Call any timeout routines which are now due.
1677  */
1678 static void
1679 calltimeout()
1680 {
1681     struct callout *p;
1682 
1683     while (callout != NULL) {
1684 	p = callout;
1685 
1686 	if (gettimeofday(&timenow, NULL) < 0)
1687 	    fatal("Failed to get time of day: %m");
1688 	if (!(p->c_time.tv_sec < timenow.tv_sec
1689 	      || (p->c_time.tv_sec == timenow.tv_sec
1690 		  && p->c_time.tv_usec <= timenow.tv_usec)))
1691 	    break;		/* no, it's not time yet */
1692 
1693 	callout = p->c_next;
1694 	(*p->c_func)(p->c_arg);
1695 
1696 	free((char *) p);
1697     }
1698 }
1699 
1700 
1701 /*
1702  * timeleft - return the length of time until the next timeout is due.
1703  */
1704 static struct timeval *
1705 timeleft(tvp)
1706     struct timeval *tvp;
1707 {
1708     if (callout == NULL)
1709 	return (NULL);
1710 
1711     (void) gettimeofday(&timenow, NULL);
1712     tvp->tv_sec = callout->c_time.tv_sec - timenow.tv_sec;
1713     tvp->tv_usec = callout->c_time.tv_usec - timenow.tv_usec;
1714     if (tvp->tv_usec < 0) {
1715 	tvp->tv_usec += 1000000;
1716 	tvp->tv_sec -= 1;
1717     }
1718     if (tvp->tv_sec < 0)
1719 	tvp->tv_sec = tvp->tv_usec = 0;
1720 
1721     return (tvp);
1722 }
1723 
1724 
1725 /*
1726  * kill_my_pg - send a signal to our process group, and ignore it ourselves.
1727  */
1728 static void
1729 kill_my_pg(sig)
1730     int sig;
1731 {
1732     struct sigaction act, oldact;
1733     sigset_t mask;
1734 
1735     BZERO(&act, sizeof (act));
1736     act.sa_handler = SIG_IGN;
1737     (void) sigemptyset(&mask);
1738     (void) sigaddset(&mask, sig);
1739     /*
1740      * Ignore signal 'sig' temporarily, before finally re-activating the
1741      * original handler.  We need to do it in the following sequence, since
1742      * otherwise the signal handler for 'sig' will be called forever.
1743      */
1744     if (sigaction(sig, &act, &oldact) < 0) {
1745 	fatal("kill_my_pg: couldn't establish signal handler (%d): %m", sig);
1746     }
1747     (void) sigprocmask(SIG_UNBLOCK, &mask, NULL);
1748     /*
1749      * Send signal 'sig' to all processes whose process group ID is equal
1750      * to the process group ID of the sender.
1751      */
1752     (void) kill(0, sig);
1753     if (sigaction(sig, &oldact, NULL) < 0) {
1754 	fatal("kill_my_pg: couldn't establish signal handler (%d): %m", sig);
1755     }
1756 }
1757 
1758 
1759 /*
1760  * hup - Catch SIGHUP signal.
1761  *
1762  * Indicates that the physical layer has been disconnected.
1763  * We don't rely on this indication; if the user has sent this
1764  * signal, we just take the link down.
1765  */
1766 static void
1767 hup(sig)
1768     int sig;
1769 {
1770     info("Hangup (SIGHUP)");
1771     kill_link = 1;
1772     if (status != EXIT_HANGUP)
1773 	status = EXIT_USER_REQUEST;
1774     if (conn_running > 0)
1775 	/* Send the signal to the [dis]connector process(es) also */
1776 	kill_my_pg(sig);
1777     if (charshunt_pid)
1778 	(void) kill(charshunt_pid, sig);
1779     if (waiting)
1780 	siglongjmp(sigjmp, 1);
1781 }
1782 
1783 
1784 /*
1785  * term - Catch SIGTERM signal and SIGINT signal (^C/del).
1786  *
1787  * Indicates that we should initiate a graceful disconnect and exit.
1788  */
1789 /*ARGSUSED*/
1790 static void
1791 term(sig)
1792     int sig;
1793 {
1794     info("Terminating on signal %d.", sig);
1795     persist = 0;		/* don't try to restart */
1796     kill_link = 1;
1797     status = EXIT_USER_REQUEST;
1798     if (conn_running > 0)
1799 	/* Send the signal to the [dis]connector process(es) also */
1800 	kill_my_pg(sig);
1801     if (charshunt_pid)
1802 	(void) kill(charshunt_pid, sig);
1803     if (waiting)
1804 	siglongjmp(sigjmp, 1);
1805 }
1806 
1807 
1808 /*
1809  * chld - Catch SIGCHLD signal.
1810  * Sets a flag so we will call reap_kids in the mainline.
1811  */
1812 /*ARGSUSED*/
1813 static void
1814 chld(sig)
1815     int sig;
1816 {
1817     got_sigchld = 1;
1818     if (waiting)
1819 	siglongjmp(sigjmp, 1);
1820 }
1821 
1822 /*
1823  * toggle_debug - Catch SIGUSR1 signal.
1824  *
1825  * Toggle debug flag.
1826  */
1827 /*ARGSUSED*/
1828 static void
1829 toggle_debug(sig)
1830     int sig;
1831 {
1832     if (debug) {
1833 	print_ncpstate(0, NULL);
1834 	dbglog("debug logging disabled");
1835 	(void) setlogmask(LOG_UPTO(LOG_WARNING));
1836 	debug = 0;
1837     } else {
1838 	(void) setlogmask(LOG_UPTO(LOG_DEBUG));
1839 	dbglog("debug logging enabled");
1840 	print_ncpstate(0, NULL);
1841 	debug = 1;
1842     }
1843 }
1844 
1845 
1846 /*
1847  * open_ccp - Catch SIGUSR2 signal.
1848  *
1849  * Try to (re)negotiate compression.
1850  */
1851 /*ARGSUSED*/
1852 static void
1853 open_ccp(sig)
1854     int sig;
1855 {
1856     open_ccp_flag = 1;
1857     if (waiting)
1858 	siglongjmp(sigjmp, 1);
1859 }
1860 
1861 
1862 /*
1863  * bad_signal - We've caught a fatal signal.  Clean up state and exit.
1864  */
1865 static void
1866 bad_signal(sig)
1867     int sig;
1868 {
1869     static int crashed = 0;
1870 
1871     if (crashed)
1872 	_exit(127);
1873     crashed = 1;
1874     error("Fatal signal %d", sig);
1875     if (conn_running > 0)
1876 	kill_my_pg(SIGTERM);
1877     if (charshunt_pid)
1878 	(void) kill(charshunt_pid, SIGTERM);
1879     die(127);
1880 }
1881 
1882 
1883 /*
1884  * device_script - run a program to talk to the serial device
1885  * (e.g. to run the connector or disconnector script).
1886  */
1887 static int
1888 device_script(program, in, out, dont_wait, optname)
1889     char *program;
1890     int in, out;
1891     int dont_wait;
1892     char *optname;
1893 {
1894     pid_t pid;
1895     int status = -1;
1896     int errfd;
1897     int envpipe[2];
1898 
1899     envpipe[0] = envpipe[1] = -1;
1900     if (!dont_wait && device_pipe_hook != NULL && pipe(envpipe) == -1) {
1901 	error("Cannot create pipe for child: %m");
1902 	return (-1);
1903     }
1904 
1905     ++conn_running;
1906     pid = fork();
1907 
1908     if (pid == (pid_t)-1) {
1909 	--conn_running;
1910 	error("Failed to create child process: %m");
1911 	return (-1);
1912     }
1913 
1914     if (pid == (pid_t)0) {
1915 	sys_close();
1916 	closelog();
1917 	if (envpipe[0] >= 0) {
1918 	    if (envpipe[1] <= 2)
1919 		envpipe[1] = dup(envpipe[1]);
1920 	    (void) close(envpipe[0]);
1921 	}
1922 	if (in == 2) {
1923 	    /* aargh!!! */
1924 	    int newin = dup(in);
1925 	    if (in == out)
1926 		out = newin;
1927 	    in = newin;
1928 	} else if (out == 2) {
1929 	    out = dup(out);
1930 	}
1931 	if (log_to_fd >= 0) {
1932 	    if (log_to_fd != 2) {
1933 		if (dup2(log_to_fd, 2) < 0)
1934 		    error("dup2(log_to_fd, STDERR) failed: %m");
1935 	    }
1936 	} else {
1937 	    (void) close(2);
1938 	    errfd = open(_PATH_CONNERRS, O_WRONLY | O_APPEND | O_CREAT, 0600);
1939 	    if (errfd >= 0 && errfd != 2) {
1940 		if (dup2(errfd, 2) < 0)
1941 		    error("dup2(errfd, STDERR) failed: %m");
1942 		(void) close(errfd);
1943 	    }
1944 	}
1945 	if (in != 0) {
1946 	    if (out == 0)
1947 		out = dup(out);
1948 	    if (dup2(in, 0) < 0)
1949 		error("dup2(in, STDIN) failed: %m");
1950 	}
1951 	if (out != 1) {
1952 	    if (dup2(out, 1) < 0)
1953 		error("dup2(out, STDOUT) failed: %m");
1954 	}
1955 	if (envpipe[0] >= 0 && dup2(envpipe[1], 3) < 0)
1956 	    error("dup2(pipe, pipeout) failed: %m");
1957 	if (real_ttyfd > 2)
1958 	    (void) close(real_ttyfd);
1959 	if (pty_master > 2)
1960 	    (void) close(pty_master);
1961 	if (pty_slave > 2) {
1962 	    (void) close(pty_slave);
1963 	    pty_slave = -1;
1964 	}
1965 	(void) setuid(uid);
1966 	if (getuid() != uid) {
1967 	    error("setuid failed");
1968 	    exit(1);
1969 	}
1970 	(void) setgid(getgid());
1971 	if (script_env != NULL) {
1972 	    while (*script_env != NULL) {
1973 		if (putenv(*script_env) == -1)
1974 		    warn("unable to set %s for %s: %m", *script_env, program);
1975 		script_env++;
1976 	    }
1977 	}
1978 	(void) execl("/bin/sh", "sh", "-c", program, (char *)0);
1979 	error("could not exec /bin/sh: %m");
1980 	exit(99);
1981 	/* NOTREACHED */
1982     }
1983 
1984     if (debug)
1985 	dbglog("%s option: '%s' started (pid %d)", optname, program, pid);
1986     if (dont_wait) {
1987 	record_child(pid, program, NULL, NULL);
1988 	status = 0;
1989     } else {
1990 	if (envpipe[0] >= 0) {
1991 	    (void) close(envpipe[1]);
1992 	    (*device_pipe_hook)(envpipe[0]);
1993 	}
1994 	while (waitpid(pid, &status, 0) < 0) {
1995 	    if (errno == EINTR)
1996 		continue;
1997 	    fatal("error waiting for (dis)connection process: %m");
1998 	}
1999 	if (envpipe[0] >= 0)
2000 	    (void) close(envpipe[0]);
2001 	--conn_running;
2002     }
2003 
2004     return (status == 0 ? 0 : -1);
2005 }
2006 
2007 
2008 /*
2009  * run-program - execute a program with given arguments,
2010  * but don't wait for it.
2011  * If the program can't be executed, logs an error unless
2012  * must_exist is 0 and the program file doesn't exist.
2013  * Returns -1 if it couldn't fork, 0 if the file doesn't exist
2014  * or isn't an executable plain file, or the process ID of the child.
2015  * If done != NULL, (*done)(arg, int) will be called later (within
2016  * reap_kids) if this routine returns value > 0.
2017  */
2018 pid_t
2019 run_program(prog, args, must_exist, done, arg)
2020     char *prog;
2021     char **args;
2022     int must_exist;
2023     void (*done) __P((void *arg, int status));
2024     void *arg;
2025 {
2026     pid_t pid;
2027     struct stat sbuf;
2028     int retv;
2029 
2030     /*
2031      * First check if the file exists and is executable.
2032      * We don't use access() because that would use the
2033      * real user-id, which might not be root, and the script
2034      * might be accessible only to root.
2035      */
2036     errno = EINVAL;
2037     if (stat(prog, &sbuf) < 0 || !S_ISREG(sbuf.st_mode)
2038 	|| (sbuf.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0) {
2039 	if (must_exist || errno != ENOENT)
2040 	    warn("Can't execute %s: %m", prog);
2041 	return (0);
2042     }
2043 
2044     if (updown_script_hook != NULL) {
2045 	retv = (*updown_script_hook)((const char ***)&args);
2046 	if (retv == -1) {
2047 	    return (-1);
2048 	}
2049     }
2050 
2051     pid = fork();
2052     if (pid == (pid_t)-1) {
2053 	error("Failed to create child process for %s: %m", prog);
2054 	return (-1);
2055     }
2056     if (pid == (pid_t)0) {
2057 	int new_fd;
2058 
2059 	/* Leave the current location */
2060 	(void) setsid();	/* No controlling tty. */
2061 	(void) umask (S_IRWXG|S_IRWXO);
2062 	(void) chdir ("/");	/* no current directory. */
2063 	(void) setuid(0);	/* set real UID = root */
2064 	(void) setgid(getegid());
2065 
2066 	/* Ensure that nothing of our device environment is inherited. */
2067 	sys_close();
2068 	closelog();
2069 	(void) close(0);
2070 	(void) close(1);
2071 	(void) close(2);
2072 	(void) close(ttyfd);  /* tty interface to the ppp device */
2073 	if (real_ttyfd >= 0)
2074 	    (void) close(real_ttyfd);
2075 
2076         /* Don't pass handles to the PPP device, even by accident. */
2077 	new_fd = open (_PATH_DEVNULL, O_RDWR);
2078 	if (new_fd >= 0) {
2079 	    if (new_fd != 0) {
2080 	        if (dup2(new_fd, 0) < 0) /* stdin <- /dev/null */
2081 		    error("dup2(/dev/null, STDIN) failed: %m");
2082 		(void) close(new_fd);
2083 	    }
2084 	    if (dup2(0, 1) < 0) /* stdout -> /dev/null */
2085 		error("dup2(/dev/null, STDOUT) failed: %m");
2086 	    if (dup2(0, 2) < 0) /* stderr -> /dev/null */
2087 		error("dup2(/dev/null, STDERR) failed: %m");
2088 	}
2089 
2090 #ifdef BSD
2091 	/* Force the priority back to zero if pppd is running higher. */
2092 	if (setpriority (PRIO_PROCESS, 0, 0) < 0)
2093 	    warn("can't reset priority to 0: %m");
2094 #endif
2095 
2096 	/* SysV recommends a second fork at this point. */
2097 
2098 	/* run the program */
2099 	(void) execve(prog, args, script_env);
2100 	if (must_exist || errno != ENOENT) {
2101 	    /* have to reopen the log, there's nowhere else
2102 	       for the message to go. */
2103 	    reopen_log();
2104 	    syslog(LOG_ERR, "Can't execute %s: %m", prog);
2105 	    closelog();
2106 	}
2107 	_exit(-1);
2108     }
2109 
2110     if (debug)
2111 	dbglog("Script %s started (pid %d)", prog, pid);
2112     record_child(pid, prog, done, arg);
2113 
2114     return (pid);
2115 }
2116 
2117 
2118 /*
2119  * record_child - add a child process to the list for reap_kids
2120  * to use.
2121  */
2122 static void
2123 record_child(pid, prog, done, arg)
2124     pid_t pid;
2125     char *prog;
2126     void (*done) __P((void *, int));
2127     void *arg;
2128 {
2129     struct subprocess *chp;
2130 
2131     ++n_children;
2132 
2133     chp = (struct subprocess *) malloc(sizeof(struct subprocess));
2134     if (chp == NULL) {
2135 	warn("losing track of %s process", prog);
2136     } else {
2137 	chp->pid = pid;
2138 	chp->prog = prog;
2139 	chp->done = done;
2140 	chp->arg = arg;
2141 	chp->next = children;
2142 	children = chp;
2143     }
2144 }
2145 
2146 
2147 /*
2148  * reap_kids - get status from any dead child processes,
2149  * and log a message for abnormal terminations.
2150  */
2151 static int
2152 reap_kids(waitfor)
2153     int waitfor;
2154 {
2155     pid_t pid;
2156     int status, i;
2157     struct subprocess *chp, **prevp;
2158 
2159     got_sigchld = 0;
2160     if (n_children == 0)
2161 	return (0);
2162 
2163     /*CONSTANTCONDITION*/
2164     while (1) {
2165 	pid = waitpid(-1, &status, (waitfor ? 0 : WNOHANG));
2166 	if (pid == 0) {
2167 	    break;	/* return 0 */
2168 	} else if (pid == -1) {
2169 	    if (errno == EINTR)
2170 		continue;
2171 	    if (errno != ECHILD)
2172 		error("Error waiting for child process: %m");
2173 	    return (-1);
2174 	} else {
2175 	    for (prevp = &children; (chp = *prevp) != NULL;
2176 		prevp = &chp->next) {
2177 		if (chp->pid == pid) {
2178 		    --n_children;
2179 		    *prevp = chp->next;
2180 		    break;
2181 		}
2182 	    }
2183 	    if (WIFSIGNALED(status) || WIFSTOPPED(status)) {
2184 		i = WIFSIGNALED(status) ? WTERMSIG(status) : WSTOPSIG(status);
2185 		warn("Child process %s (pid %d) %s with signal %d (%s)",
2186 		    (chp != NULL ? chp->prog : "??"), pid,
2187 		    (WIFSIGNALED(status) ? "terminated" : "stopped"),
2188 		    i, signal_name(i));
2189 	    } else if (debug) {
2190 		dbglog("Child process %s finished (pid %d), status = %d",
2191 		       (chp != NULL ? chp->prog: "??"), pid,
2192 		    WEXITSTATUS(status));
2193 	    }
2194 	    if ((chp != NULL) && (chp->done != NULL))
2195 		(*chp->done)(chp->arg, status);
2196 	    if (chp != NULL)
2197 		free(chp);
2198 	}
2199     }
2200     return (0);
2201 }
2202 
2203 /*
2204  * infanticide - timeout while waiting for child process.
2205  */
2206 /*ARGSUSED*/
2207 static void
2208 infanticide(sig)
2209     int sig;
2210 {
2211     struct subprocess *chp;
2212     static int runcount = 0;
2213 
2214     if (runcount < 2) {
2215 	for (chp = children; chp != NULL; chp = chp->next)
2216 	    (void) kill(chp->pid, runcount == 0 ? SIGTERM : SIGKILL);
2217     } else {
2218 	kill_my_pg(SIGTERM);
2219 	/* Quit and hope for the best. */
2220 	n_children = 0;
2221     }
2222     runcount++;
2223 }
2224 
2225 /*
2226  * Perform final wait before exiting.
2227  */
2228 static void
2229 final_reap()
2230 {
2231     struct sigaction sa;
2232     struct subprocess *chp;
2233 
2234     if (n_children > 0 && debug) {
2235 	dbglog("Waiting for %d child processes...", n_children);
2236 	for (chp = children; chp != NULL; chp = chp->next)
2237 	    dbglog("  pid %d: %s", chp->pid, chp->prog);
2238     }
2239     BZERO(&sa, sizeof (sa));
2240 /*CONSTANTCONDITION*/ SIGNAL(SIGALRM, infanticide);
2241     while (n_children > 0) {
2242 	(void) alarm(7);
2243 	if (reap_kids(1) < 0)
2244 	    break;
2245     }
2246     (void) alarm(0);
2247 }
2248 
2249 /*
2250  * novm - log an error message saying we ran out of memory, and die.
2251  */
2252 void
2253 novm(msg)
2254     char *msg;
2255 {
2256     fatal("Virtual memory exhausted allocating %s\n", msg);
2257 }
2258 
2259 /*
2260  * script_setenv - set an environment variable value to be used
2261  * for scripts that we run (e.g. ip-up, auth-up, etc.)
2262  */
2263 void
2264 script_setenv(var, value, iskey)
2265     const char *var;
2266     const char *value;
2267     int iskey;
2268 {
2269     size_t varl = strlen(var);
2270     size_t vl = varl + strlen(value) + 2;
2271     int i;
2272     char *p, *newstring;
2273 
2274     /*
2275      * XXX: Can we assert that a tdb write lock is held here ?  It appears that
2276      *	    Linux's use of tdb is not safe.
2277      */
2278     newstring = (char *) malloc(vl+1);
2279     if (newstring == NULL) {
2280 	novm("script environment string");
2281 	return;
2282     }
2283     *newstring++ = iskey;
2284     (void) slprintf(newstring, vl, "%s=%s", var, value);
2285 
2286     /* check if this variable is already set */
2287     if (script_env != NULL) {
2288 	for (i = 0; (p = script_env[i]) != NULL; ++i) {
2289 	    if (strncmp(p, var, varl) == 0 && p[varl] == '=') {
2290 #ifdef HAVE_MULTILINK
2291 		if (p[-1] != '\0' && pppdb != NULL)
2292 		    delete_db_key(p);
2293 #endif
2294 		free(p-1);
2295 		script_env[i] = newstring;
2296 #ifdef HAVE_MULTILINK
2297 		if (iskey && pppdb != NULL)
2298 		    add_db_key(newstring);
2299 		update_db_entry();
2300 #endif
2301 		return;
2302 	    }
2303 	}
2304     } else {
2305 	/* no space allocated for script env. ptrs. yet */
2306 	i = 0;
2307 	script_env = (char **) malloc(16 * sizeof(char *));
2308 	if (script_env == NULL) {
2309 	    novm("script environment variable.");
2310 	    return;
2311 	}
2312 	s_env_nalloc = 16;
2313     }
2314 
2315     /* reallocate script_env with more space if needed */
2316     if (i + 1 >= s_env_nalloc) {
2317 	int new_n = i + 17;
2318 	char **newenv = (char **) realloc((void *)script_env,
2319 					  new_n * sizeof(char *));
2320 	if (newenv == NULL) {
2321 	    novm("expanded script environment variable.");
2322 	    return;
2323 	}
2324 	script_env = newenv;
2325 	s_env_nalloc = new_n;
2326     }
2327 
2328     script_env[i] = newstring;
2329     script_env[i+1] = NULL;
2330 
2331 #ifdef HAVE_MULTILINK
2332     if (pppdb != NULL) {
2333 	if (iskey)
2334 	    add_db_key(newstring);
2335 	update_db_entry();
2336     }
2337 #endif
2338 }
2339 
2340 /*
2341  * script_unsetenv - remove a variable from the environment
2342  * for scripts.
2343  */
2344 void
2345 script_unsetenv(var)
2346     const char *var;
2347 {
2348     int vl = strlen(var);
2349     int i;
2350     char *p;
2351 
2352     /*
2353      * XXX: Can we assert that a tdb write lock is held here ?  It appears that
2354      *	    Linux's use of tdb is not safe.
2355      */
2356     if (script_env == NULL)
2357 	return;
2358     for (i = 0; (p = script_env[i]) != NULL; ++i) {
2359 	if (strncmp(p, var, vl) == 0 && p[vl] == '=') {
2360 #ifdef HAVE_MULTILINK
2361 	    if (p[-1] != '\0' && pppdb != NULL)
2362 		delete_db_key(p);
2363 #endif
2364 	    free(p-1);
2365 	    while ((script_env[i] = script_env[i+1]) != NULL)
2366 		++i;
2367 	    break;
2368 	}
2369     }
2370 #ifdef HAVE_MULTILINK
2371     if ((pppdb != NULL) && (p != NULL))
2372 	update_db_entry();
2373 #endif
2374 }
2375 
2376 /*
2377  * script_getenv - find a variable in the script environment.
2378  */
2379 const char *
2380 script_getenv(var)
2381     const char *var;
2382 {
2383     int vl = strlen(var);
2384     int i;
2385     char *p;
2386 
2387     if (script_env == NULL)
2388 	return (NULL);
2389     for (i = 0; (p = script_env[i]) != NULL; ++i) {
2390 	if (strncmp(p, var, vl) == 0 && p[vl] == '=')
2391 	    return ((const char *)p+vl+1);
2392     }
2393     return (NULL);
2394 }
2395 
2396 #ifdef HAVE_MULTILINK
2397 /*
2398  * update_db_entry - update our entry in the database.
2399  */
2400 static void
2401 update_db_entry()
2402 {
2403     TDB_DATA key, dbuf;
2404     int vlen, i;
2405     char *p, *q, *vbuf;
2406 
2407     if (script_env == NULL)
2408 	return;
2409     /*
2410      * vlen needs to be initialized as 1, or otherwise, the last string
2411      * is truncated by slprintf.
2412      */
2413     vlen = 1;
2414     for (i = 0; (p = script_env[i]) != NULL; ++i)
2415 	vlen += strlen(p) + 1;
2416     vbuf = malloc(vlen);
2417     if (vbuf == NULL)
2418 	novm("database entry");
2419     q = vbuf;
2420     for (i = 0; (p = script_env[i]) != NULL; ++i)
2421 	q += slprintf(q, vbuf + vlen - q, "%s;", p);
2422 
2423     key.dptr = db_key;
2424     key.dsize = strlen(db_key);
2425     dbuf.dptr = vbuf;
2426     dbuf.dsize = vlen;
2427     if (tdb_store(pppdb, key, dbuf, TDB_REPLACE))
2428 	error("tdb_store failed: %s", tdb_error(pppdb));
2429 }
2430 
2431 /*
2432  * add_db_key - add a key that we can use to look up our database entry.
2433  */
2434 static void
2435 add_db_key(str)
2436     const char *str;
2437 {
2438     TDB_DATA key, dbuf;
2439 
2440     key.dptr = (char *) str;
2441     key.dsize = strlen(str);
2442     dbuf.dptr = db_key;
2443     dbuf.dsize = strlen(db_key);
2444     if (tdb_store(pppdb, key, dbuf, TDB_REPLACE))
2445 	error("tdb_store key failed: %s", tdb_error(pppdb));
2446 }
2447 
2448 /*
2449  * delete_db_key - delete a key for looking up our database entry.
2450  */
2451 static void
2452 delete_db_key(str)
2453     const char *str;
2454 {
2455     TDB_DATA key;
2456 
2457     key.dptr = (char *) str;
2458     key.dsize = strlen(str);
2459     (void) tdb_delete(pppdb, key);
2460 }
2461 
2462 /*
2463  * cleanup_db - delete all the entries we put in the database.
2464  */
2465 static void
2466 cleanup_db()
2467 {
2468     TDB_DATA key;
2469     int i;
2470     char *p;
2471 
2472     key.dptr = db_key;
2473     key.dsize = strlen(db_key);
2474     (void) tdb_delete(pppdb, key);
2475     for (i = 0; (p = script_env[i]) != NULL; ++i)
2476 	if (p[-1] != '\0')
2477 	    delete_db_key(p);
2478 }
2479 #endif /* HAVE_MULTILINK */
2480 
2481 /*
2482  * open_socket - establish a stream socket connection to the nominated
2483  * host and port.
2484  * XXX: Need IPv6 support for those systems that support it (use getaddrinfo),
2485  *	but requires portability changes.
2486  */
2487 static int
2488 open_socket(dest)
2489     char *dest;
2490 {
2491     char *sep, *endp = NULL;
2492     int sock;
2493     int port = -1;
2494     u_int32_t host;
2495     struct hostent *hent = NULL;
2496     struct sockaddr_in sad;
2497     struct servent *se;
2498 
2499     /* parse host:port and resolve host to an IP address */
2500     sep = strchr(dest, ':');
2501     if (sep != NULL) {
2502 	se = getservbyname((const char *)sep+1, "tcp");
2503 	if (se != NULL) {
2504 	    port = ntohs(se->s_port);
2505 	} else {
2506 	    port = strtol(sep+1, &endp, 10);
2507 	    if (endp == sep+1 || *endp != '\0') {
2508 		error("Can't parse host:port for socket destination");
2509 		return (-1);
2510 	    }
2511 	}
2512     }
2513     if (port < 0 || port > 65535 || sep == dest) {
2514 	error("Can't parse host:port for socket destination");
2515 	return (-1);
2516     }
2517     *sep = '\0';
2518     host = inet_addr(dest);
2519     if (host == (u_int32_t) -1) {
2520 	hent = gethostbyname(dest);
2521 	if (hent == NULL) {
2522 	    error("%s: unknown host in socket option", dest);
2523 	    *sep = ':';
2524 	    return (-1);
2525 	}
2526 	BCOPY(hent->h_addr_list[0], &host, sizeof(host));
2527 	hent->h_addr_list++;
2528     }
2529     *sep = ':';
2530 
2531     for (;;) {
2532 	/* get a socket and connect it to the other end */
2533 	sock = socket(PF_INET, SOCK_STREAM, 0);
2534 	if (sock < 0) {
2535 	    error("Can't create socket: %m");
2536 	    return (-1);
2537 	}
2538 	BZERO(&sad, sizeof(sad));
2539 	sad.sin_family = AF_INET;
2540 	sad.sin_port = htons(port);
2541 	sad.sin_addr.s_addr = host;
2542 	if (connect(sock, (struct sockaddr *)&sad, sizeof(sad)) >= 0) {
2543 	    break;  /* return sock file descriptor */
2544 	}
2545 	if ((hent != NULL) && (hent->h_addr_list != NULL)) {
2546 	    BCOPY(hent->h_addr_list[0], &host, sizeof(host));
2547 	    hent->h_addr_list++;
2548 	    (void) close(sock);
2549 	    continue;
2550 	}
2551 	error("Can't connect to %s: %m", dest);
2552 	(void) close(sock);
2553 	return (-1);
2554     }
2555     return (sock);
2556 }
2557 
2558 /*
2559  * print_ncpstate - prints out current NCP state.
2560  *
2561  * We're normally called from SIGUSR1 here, but this is safe because
2562  * these signals are blocked unless we're idle waiting for events.
2563  * There's no need to otherwise lock the data structures referenced.
2564  */
2565 void
2566 print_ncpstate(unit, strptr)
2567     int unit;
2568     FILE *strptr;
2569 {
2570     struct protent *protp;
2571     int i;
2572 
2573     (void) flprintf(strptr, "In %s phase\n", phase_name(phase));
2574     for (i = 0; (protp = protocols[i]) != NULL; ++i) {
2575 	if (protp->print_stat != NULL)
2576 	    (*protp->print_stat)(unit, strptr);
2577     }
2578     sys_print_state(strptr);
2579 }
2580 
2581 /*
2582  * start_charshunt - create a child process to run the character shunt.
2583  */
2584 static int
2585 start_charshunt(ifd, ofd)
2586     int ifd, ofd;
2587 {
2588     pid_t cpid;
2589 
2590     cpid = fork();
2591     if (cpid == (pid_t)-1) {
2592 	error("Can't fork process for character shunt: %m");
2593 	return (0);
2594     }
2595     if (cpid == (pid_t)0) {
2596 	/* child */
2597 	(void) close(pty_slave);
2598 	pty_slave = -1;
2599 	(void) setgid(getgid());
2600 	(void) setuid(uid);
2601 	if (getuid() != uid)
2602 	    fatal("setuid failed");
2603 	if (!nodetach)
2604 	    log_to_fd = -1;
2605 	charshunt(ifd, ofd, record_file);
2606 	exit(0);
2607     }
2608     charshunt_pid = cpid;
2609     (void) close(pty_master);
2610     pty_master = -1;
2611     ttyfd = pty_slave;
2612     record_child(cpid, "pppd (charshunt)", charshunt_done, NULL);
2613     return (1);
2614 }
2615 
2616 /*ARGSUSED*/
2617 static void
2618 charshunt_done(arg, status)
2619     void *arg;
2620     int status;
2621 {
2622     charshunt_pid = (pid_t)0;
2623 }
2624 
2625 static void
2626 reportme(int signo)
2627 {
2628     dbglog("charshunt taking signal %d", signo);
2629     exit(1);
2630 }
2631 
2632 /*
2633  * charshunt - the character shunt, which passes characters between
2634  * the pty master side and the serial port (or stdin/stdout).
2635  * This runs as the user (not as root).
2636  * (We assume ofd >= ifd which is true the way this gets called. :-).
2637  */
2638 static void
2639 charshunt(ifd, ofd, record_file)
2640     int ifd, ofd;
2641     char *record_file;
2642 {
2643     int n, nfds;
2644     fd_set ready, writey;
2645     u_char *ibufp, *obufp;
2646     int nibuf, nobuf;
2647     int flags;
2648     struct timeval lasttime;
2649     FILE *recordf = NULL;
2650     int ilevel, olevel, max_level;
2651     struct timeval levelt, tout, *top;
2652 
2653     /*
2654      * Reset signal handlers.
2655      */
2656     (void) signal(SIGHUP, SIG_IGN);		/* Hangup */
2657     (void) signal(SIGINT, reportme);		/* Interrupt */
2658     (void) signal(SIGTERM, reportme);		/* Terminate */
2659     (void) signal(SIGCHLD, reportme);
2660     (void) signal(SIGUSR1, reportme);
2661     (void) signal(SIGUSR2, reportme);
2662     (void) signal(SIGABRT, reportme);
2663     (void) signal(SIGALRM, reportme);
2664     (void) signal(SIGFPE, reportme);
2665     (void) signal(SIGILL, reportme);
2666     (void) signal(SIGPIPE, reportme);
2667     (void) signal(SIGQUIT, reportme);
2668 #ifndef DEBUG
2669     (void) signal(SIGSEGV, reportme);
2670 #endif
2671 #ifdef SIGBUS
2672     (void) signal(SIGBUS, reportme);
2673 #endif
2674 #ifdef SIGEMT
2675     (void) signal(SIGEMT, reportme);
2676 #endif
2677 #ifdef SIGPOLL
2678     (void) signal(SIGPOLL, reportme);
2679 #endif
2680 #ifdef SIGPROF
2681     (void) signal(SIGPROF, reportme);
2682 #endif
2683 #ifdef SIGSYS
2684     (void) signal(SIGSYS, reportme);
2685 #endif
2686 #ifdef SIGTRAP
2687     (void) signal(SIGTRAP, reportme);
2688 #endif
2689 #ifdef SIGVTALRM
2690     (void) signal(SIGVTALRM, reportme);
2691 #endif
2692 #ifdef SIGXCPU
2693     (void) signal(SIGXCPU, reportme);
2694 #endif
2695 #ifdef SIGXFSZ
2696     (void) signal(SIGXFSZ, reportme);
2697 #endif
2698 
2699     /*
2700      * Open the record file if required.
2701      */
2702     if (record_file != NULL) {
2703 	recordf = fopen(record_file, "a");
2704 	if (recordf == NULL)
2705 	    error("Couldn't create record file %s: %m", record_file);
2706     }
2707 
2708     /* set all the fds to non-blocking mode */
2709     flags = fcntl(pty_master, F_GETFL);
2710     if (flags == -1
2711 	|| fcntl(pty_master, F_SETFL, flags | O_NONBLOCK) == -1)
2712 	warn("couldn't set pty master to nonblock: %m");
2713     flags = fcntl(ifd, F_GETFL);
2714     if (flags == -1
2715 	|| fcntl(ifd, F_SETFL, flags | O_NONBLOCK) == -1)
2716 	warn("couldn't set %s to nonblock: %m", (ifd==0? "stdin": "tty"));
2717     if (ofd != ifd) {
2718 	flags = fcntl(ofd, F_GETFL);
2719 	if (flags == -1
2720 	    || fcntl(ofd, F_SETFL, flags | O_NONBLOCK) == -1)
2721 	    warn("couldn't set stdout to nonblock: %m");
2722     }
2723 
2724     nibuf = nobuf = 0;
2725     ibufp = obufp = NULL;
2726 
2727     ilevel = olevel = 0;
2728     (void) gettimeofday(&levelt, NULL);
2729     if (max_data_rate) {
2730 	max_level = max_data_rate / 10;
2731 	if (max_level < MAXLEVELMINSIZE)
2732 	    max_level = MAXLEVELMINSIZE;
2733     } else
2734 	max_level = sizeof(inpacket_buf) + 1;
2735 
2736     nfds = (ofd > pty_master? ofd: pty_master) + 1;
2737     if (recordf != NULL) {
2738 	(void) gettimeofday(&lasttime, NULL);
2739 	(void) putc(RECMARK_TIMESTART, recordf);	/* put start marker */
2740 	(void) putc(lasttime.tv_sec >> 24, recordf);
2741 	(void) putc(lasttime.tv_sec >> 16, recordf);
2742 	(void) putc(lasttime.tv_sec >> 8, recordf);
2743 	(void) putc(lasttime.tv_sec, recordf);
2744 	lasttime.tv_usec = 0;
2745     }
2746 
2747     while (nibuf != 0 || nobuf != 0 || ofd >= 0 || pty_master >= 0) {
2748 	top = 0;
2749 	tout.tv_sec = 0;
2750 	tout.tv_usec = 10000;
2751 	FD_ZERO(&ready);
2752 	FD_ZERO(&writey);
2753 	if (nibuf != 0) {
2754 	    if (ilevel >= max_level)
2755 		top = &tout;
2756 	    else if (pty_master >= 0)
2757 		FD_SET(pty_master, &writey);
2758 	} else if (ifd >= 0)
2759 	    FD_SET(ifd, &ready);
2760 	if (nobuf != 0) {
2761 	    if (olevel >= max_level)
2762 		top = &tout;
2763 	    else if (ofd >= 0)
2764 		FD_SET(ofd, &writey);
2765 	} else {
2766 	    /* Don't read from pty if it's gone or it has closed. */
2767 	    if (pty_master >= 0 && ofd >= 0)
2768 		FD_SET(pty_master, &ready);
2769 	}
2770 	if (select(nfds, &ready, &writey, NULL, top) < 0) {
2771 	    if (errno != EINTR)
2772 		fatal("select");
2773 	    continue;
2774 	}
2775 	if (max_data_rate) {
2776 	    double dt;
2777 	    int nbt;
2778 	    struct timeval now;
2779 
2780 	    (void) gettimeofday(&now, NULL);
2781 	    dt = (now.tv_sec - levelt.tv_sec
2782 		  + (now.tv_usec - levelt.tv_usec) / 1e6);
2783 	    nbt = (int)(dt * max_data_rate);
2784 	    ilevel = (nbt < 0 || nbt > ilevel)? 0: ilevel - nbt;
2785 	    olevel = (nbt < 0 || nbt > olevel)? 0: olevel - nbt;
2786 	    levelt = now;
2787 	} else
2788 	    ilevel = olevel = 0;
2789 	if (FD_ISSET(ifd, &ready)) {
2790 	    ibufp = inpacket_buf;
2791 	    nibuf = read(ifd, ibufp, sizeof(inpacket_buf));
2792 	    if (nibuf < 0 && errno == EIO)
2793 		nibuf = 0;
2794 	    if (nibuf < 0 || pty_master == -1) {
2795 		if (errno != EINTR && errno != EAGAIN) {
2796 		    error("Error reading standard input: %m");
2797 		    break;
2798 		}
2799 		nibuf = 0;
2800 	    } else if (nibuf == 0) {
2801 		/* end of file from stdin */
2802 		(void) close(pty_master);
2803 		pty_master = -1;
2804 		(void) close(ifd);
2805 		ifd = -1;
2806 		if (recordf)
2807 		    if (!record_write(recordf, RECMARK_ENDRECV, NULL, 0,
2808 			&lasttime))
2809 			recordf = NULL;
2810 	    } else {
2811 		FD_SET(pty_master, &writey);
2812 		if (recordf)
2813 		    if (!record_write(recordf, RECMARK_STARTRECV, ibufp, nibuf,
2814 			&lasttime))
2815 			recordf = NULL;
2816 	    }
2817 	}
2818 	if (ofd >= 0 && pty_master >= 0 && FD_ISSET(pty_master, &ready)) {
2819 	    obufp = outpacket_buf;
2820 	    nobuf = read(pty_master, obufp, sizeof(outpacket_buf));
2821 	    if (nobuf < 0 && errno == EIO)
2822 		nobuf = 0;
2823 	    if (nobuf < 0 || ofd == -1) {
2824 		if (!(errno == EINTR || errno == EAGAIN)) {
2825 		    error("Error reading pseudo-tty master: %m");
2826 		    break;
2827 		}
2828 		nobuf = 0;
2829 	    } else if (nobuf == 0) {
2830 		/* end of file from the pty - slave side has closed */
2831 		nibuf = 0;
2832 		(void) close(ofd);
2833 		ofd = -1;
2834 		if (recordf)
2835 		    if (!record_write(recordf, RECMARK_ENDSEND, NULL, 0,
2836 			&lasttime))
2837 			recordf = NULL;
2838 	    } else {
2839 		FD_SET(ofd, &writey);
2840 		if (recordf)
2841 		    if (!record_write(recordf, RECMARK_STARTSEND, obufp, nobuf,
2842 			&lasttime))
2843 			recordf = NULL;
2844 	    }
2845 	}
2846 	if (ofd == -1)
2847 	    nobuf = 0;
2848 	else if (FD_ISSET(ofd, &writey)) {
2849 	    n = nobuf;
2850 	    if (olevel + n > max_level)
2851 		n = max_level - olevel;
2852 	    n = write(ofd, obufp, n);
2853 	    if (n < 0) {
2854 		if (errno == EIO) {
2855 		    (void) close(ofd);
2856 		    ofd = -1;
2857 		    nobuf = 0;
2858 		} else if (errno != EAGAIN && errno != EINTR) {
2859 		    error("Error writing standard output: %m");
2860 		    break;
2861 		}
2862 	    } else {
2863 		obufp += n;
2864 		nobuf -= n;
2865 		olevel += n;
2866 	    }
2867 	}
2868 	if (pty_master == -1)
2869 	    nibuf = 0;
2870 	else if (FD_ISSET(pty_master, &writey)) {
2871 	    n = nibuf;
2872 	    if (ilevel + n > max_level)
2873 		n = max_level - ilevel;
2874 	    n = write(pty_master, ibufp, n);
2875 	    if (n < 0) {
2876 		if (errno == EAGAIN || errno == EINTR)
2877 		    continue;
2878 		if (errno != EIO) {
2879 		    error("Error writing pseudo-tty master: %m");
2880 		    break;
2881 		}
2882 		(void) close(pty_master);
2883 		pty_master = -1;
2884 		nibuf = 0;
2885 	    } else {
2886 		ibufp += n;
2887 		nibuf -= n;
2888 		ilevel += n;
2889 	    }
2890 	}
2891     }
2892     exit(0);
2893 }
2894 
2895 static int
2896 record_write(f, code, buf, nb, tp)
2897     FILE *f;
2898     int code;
2899     u_char *buf;
2900     int nb;
2901     struct timeval *tp;
2902 {
2903     struct timeval now;
2904     int diff;
2905 
2906     (void) gettimeofday(&now, NULL);
2907     now.tv_usec /= 100000;	/* actually 1/10 s, not usec now */
2908     diff = (now.tv_sec - tp->tv_sec) * 10 + (now.tv_usec - tp->tv_usec);
2909     if (diff > 0) {
2910 	if (diff > 255) {
2911 	    (void) putc(RECMARK_TIMEDELTA32, f);
2912 	    (void) putc(diff >> 24, f);
2913 	    (void) putc(diff >> 16, f);
2914 	    (void) putc(diff >> 8, f);
2915 	    (void) putc(diff, f);
2916 	} else {
2917 	    (void) putc(RECMARK_TIMEDELTA8, f);
2918 	    (void) putc(diff, f);
2919 	}
2920 	*tp = now;
2921     }
2922     (void) putc(code, f);
2923     if (buf != NULL) {
2924 	(void) putc(nb >> 8, f);
2925 	(void) putc(nb, f);
2926 	(void) fwrite(buf, nb, 1, f);
2927     }
2928     (void) fflush(f);
2929     if (ferror(f)) {
2930 	error("Error writing record file: %m");
2931 	return (0);
2932     }
2933     return (1);
2934 }
2935