main.c revision 1.52 
1/*	$OpenBSD: main.c,v 1.52 2015/10/26 11:10:53 deraadt Exp $	*/
2
3/*
4 * main.c - Point-to-Point Protocol main module
5 *
6 * Copyright (c) 1984-2000 Carnegie Mellon University. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in
17 *    the documentation and/or other materials provided with the
18 *    distribution.
19 *
20 * 3. The name "Carnegie Mellon University" must not be used to
21 *    endorse or promote products derived from this software without
22 *    prior written permission. For permission or any legal
23 *    details, please contact
24 *      Office of Technology Transfer
25 *      Carnegie Mellon University
26 *      5000 Forbes Avenue
27 *      Pittsburgh, PA  15213-3890
28 *      (412) 268-4387, fax: (412) 268-7395
29 *      tech-transfer@andrew.cmu.edu
30 *
31 * 4. Redistributions of any form whatsoever must retain the following
32 *    acknowledgment:
33 *    "This product includes software developed by Computing Services
34 *     at Carnegie Mellon University (http://www.cmu.edu/computing/)."
35 *
36 * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
37 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
38 * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
39 * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
40 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
41 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
42 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
43 */
44
45#include <sys/types.h>
46#include <sys/wait.h>
47#include <sys/time.h>
48#include <sys/resource.h>
49#include <sys/stat.h>
50#include <sys/socket.h>
51#include <net/if.h>
52#include <stdio.h>
53#include <ctype.h>
54#include <stdlib.h>
55#include <string.h>
56#include <unistd.h>
57#include <limits.h>
58#include <signal.h>
59#include <errno.h>
60#include <fcntl.h>
61#include <syslog.h>
62#include <netdb.h>
63#include <utmp.h>
64#include <pwd.h>
65
66#include "pppd.h"
67#include "magic.h"
68#include "fsm.h"
69#include "lcp.h"
70#include "ipcp.h"
71#include "upap.h"
72#include "chap.h"
73#include "ccp.h"
74#include "pathnames.h"
75#include "patchlevel.h"
76
77#ifdef CBCP_SUPPORT
78#include "cbcp.h"
79#endif
80
81#if defined(SUNOS4)
82extern char *strerror();
83#endif
84
85#ifdef AT_CHANGE
86#include "atcp.h"
87#endif
88
89/* interface vars */
90char ifname[IFNAMSIZ];		/* Interface name */
91int ifunit;			/* Interface unit number */
92
93char *progname;			/* Name of this program */
94char hostname[HOST_NAME_MAX+1];	/* Our hostname */
95static char default_devnam[PATH_MAX];	/* name of default device */
96static pid_t pid;		/* Our pid */
97static uid_t uid;		/* Our real user-id */
98static int conn_running;	/* we have a [dis]connector running */
99static int crashed = 0;
100
101int ttyfd = -1;			/* Serial port file descriptor */
102mode_t tty_mode = -1;		/* Original access permissions to tty */
103int baud_rate;			/* Actual bits/second for serial device */
104int hungup;			/* terminal has been hung up */
105int privileged;			/* we're running as real uid root */
106int need_holdoff;		/* need holdoff period before restarting */
107int detached;			/* have detached from terminal */
108
109int phase;			/* where the link is at */
110int kill_link;
111int open_ccp_flag;
112
113char **script_env;		/* Env. variable values for scripts */
114int s_env_nalloc;		/* # words avail at script_env */
115
116u_char outpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for outgoing packet */
117u_char inpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for incoming packet */
118
119static int n_children;		/* # child processes still running */
120
121static int locked;		/* lock() has succeeded */
122
123char *no_ppp_msg = "Sorry - this system lacks PPP kernel support\n";
124
125/* Prototypes for procedures local to this file. */
126
127static void cleanup(void);
128static void close_tty(void);
129static void get_input(void);
130static void calltimeout(void);
131static struct timeval *timeleft(struct timeval *);
132static void kill_my_pg(int);
133static void hup(int);
134static void term(int);
135static void chld(int);
136static void toggle_debug(int);
137static void open_ccp(int);
138static void bad_signal(int);
139static void holdoff_end(void *);
140static int device_script(char *, int, int);
141static void reap_kids(void);
142static void pr_log(void *, char *, ...);
143
144extern	char	*ttyname(int);
145extern	char	*getlogin(void);
146int main(int, char *[]);
147
148#ifdef ultrix
149#undef	O_NONBLOCK
150#define	O_NONBLOCK	O_NDELAY
151#endif
152
153#ifdef ULTRIX
154#define setlogmask(x)
155#endif
156
157/*
158 * PPP Data Link Layer "protocol" table.
159 * One entry per supported protocol.
160 * The last entry must be NULL.
161 */
162struct protent *protocols[] = {
163    &lcp_protent,
164    &pap_protent,
165    &chap_protent,
166#ifdef CBCP_SUPPORT
167    &cbcp_protent,
168#endif
169    &ipcp_protent,
170    &ccp_protent,
171#ifdef AT_CHANGE
172    &atcp_protent,
173#endif
174    NULL
175};
176
177int
178main(argc, argv)
179    int argc;
180    char *argv[];
181{
182    int i, fdflags;
183    struct sigaction sa;
184    char *p;
185    struct passwd *pw;
186    struct timeval timo;
187    sigset_t mask;
188    struct protent *protp;
189    struct stat statbuf;
190    char numbuf[16];
191
192    phase = PHASE_INITIALIZE;
193    p = ttyname(0);
194    if (p)
195	strlcpy(devnam, p, PATH_MAX);
196    strlcpy(default_devnam, devnam, sizeof default_devnam);
197
198    script_env = NULL;
199
200    /* Initialize syslog facilities */
201#ifdef ULTRIX
202    openlog("pppd", LOG_PID);
203#else
204    openlog("pppd", LOG_PID | LOG_NDELAY, LOG_PPP);
205    setlogmask(LOG_UPTO(LOG_INFO));
206#endif
207
208    if (gethostname(hostname, sizeof hostname) < 0 ) {
209	option_error("Couldn't get hostname: %m");
210	die(1);
211    }
212
213    uid = getuid();
214    privileged = uid == 0;
215    snprintf(numbuf, sizeof numbuf, "%u", uid);
216    script_setenv("UID", numbuf);
217
218    /*
219     * Initialize to the standard option set, then parse, in order,
220     * the system options file, the user's options file,
221     * the tty's options file, and the command line arguments.
222     */
223    for (i = 0; (protp = protocols[i]) != NULL; ++i)
224	(*protp->init)(0);
225
226    progname = *argv;
227
228    if (!options_from_file(_PATH_SYSOPTIONS, !privileged, 0, 1)
229	|| !options_from_user())
230	exit(1);
231    scan_args(argc-1, argv+1);	/* look for tty name on command line */
232    if (!options_for_tty()
233	|| !parse_args(argc-1, argv+1))
234	exit(1);
235
236    /*
237     * Check that we are running as root.
238     */
239    if (geteuid() != 0) {
240	option_error("must be root to run %s, since it is not setuid-root",
241		     argv[0]);
242	die(1);
243    }
244
245    if (!ppp_available()) {
246	option_error(no_ppp_msg);
247	exit(1);
248    }
249
250    /*
251     * Check that the options given are valid and consistent.
252     */
253    sys_check_options();
254    auth_check_options();
255    for (i = 0; (protp = protocols[i]) != NULL; ++i)
256	if (protp->check_options != NULL)
257	    (*protp->check_options)();
258    if (demand && connector == 0) {
259	option_error("connect script required for demand-dialling\n");
260	exit(1);
261    }
262
263    script_setenv("DEVICE", devnam);
264    snprintf(numbuf, sizeof numbuf, "%d", baud_rate);
265    script_setenv("SPEED", numbuf);
266
267    /*
268     * If the user has specified the default device name explicitly,
269     * pretend they hadn't.
270     */
271    if (!default_device && strcmp(devnam, default_devnam) == 0)
272	default_device = 1;
273    if (default_device)
274	nodetach = 1;
275
276    /*
277     * Initialize system-dependent stuff and magic number package.
278     */
279    sys_init();
280    magic_init();
281    if (debug)
282	setlogmask(LOG_UPTO(LOG_DEBUG));
283
284    /*
285     * Detach ourselves from the terminal, if required,
286     * and identify who is running us.
287     */
288    if (nodetach == 0)
289	detach();
290    pid = getpid();
291    p = getlogin();
292    if (p == NULL) {
293	pw = getpwuid(uid);
294	if (pw != NULL && pw->pw_name != NULL)
295	    p = pw->pw_name;
296	else
297	    p = "(unknown)";
298    }
299    syslog(LOG_NOTICE, "pppd %s.%d%s started by %s, uid %u",
300	   VERSION, PATCHLEVEL, IMPLEMENTATION, p, uid);
301
302    /*
303     * Compute mask of all interesting signals and install signal handlers
304     * for each.  Only one signal handler may be active at a time.  Therefore,
305     * all other signals should be masked when any handler is executing.
306     */
307    sigemptyset(&mask);
308    sigaddset(&mask, SIGHUP);
309    sigaddset(&mask, SIGINT);
310    sigaddset(&mask, SIGTERM);
311    sigaddset(&mask, SIGCHLD);
312
313#define SIGNAL(s, handler)	{ \
314	sa.sa_handler = handler; \
315	if (sigaction(s, &sa, NULL) < 0) { \
316	    syslog(LOG_ERR, "Couldn't establish signal handler (%d): %m", s); \
317	    die(1); \
318	} \
319    }
320
321    sa.sa_mask = mask;
322    sa.sa_flags = 0;
323    SIGNAL(SIGHUP, hup);		/* Hangup */
324    SIGNAL(SIGINT, term);		/* Interrupt */
325    SIGNAL(SIGTERM, term);		/* Terminate */
326    SIGNAL(SIGCHLD, chld);
327
328    SIGNAL(SIGUSR1, toggle_debug);	/* Toggle debug flag */
329    SIGNAL(SIGUSR2, open_ccp);		/* Reopen CCP */
330
331    /*
332     * Install a handler for other signals which would otherwise
333     * cause pppd to exit without cleaning up.
334     */
335    SIGNAL(SIGABRT, bad_signal);
336    SIGNAL(SIGALRM, bad_signal);
337    SIGNAL(SIGFPE, bad_signal);
338    SIGNAL(SIGILL, bad_signal);
339    SIGNAL(SIGPIPE, bad_signal);
340    SIGNAL(SIGQUIT, bad_signal);
341#if SIGSEGV_CHECK
342    SIGNAL(SIGSEGV, bad_signal);
343#endif
344#ifdef SIGBUS
345    SIGNAL(SIGBUS, bad_signal);
346#endif
347#ifdef SIGEMT
348    SIGNAL(SIGEMT, bad_signal);
349#endif
350#ifdef SIGPOLL
351    SIGNAL(SIGPOLL, bad_signal);
352#endif
353#ifdef SIGPROF
354    SIGNAL(SIGPROF, bad_signal);
355#endif
356#ifdef SIGSYS
357    SIGNAL(SIGSYS, bad_signal);
358#endif
359#ifdef SIGTRAP
360    SIGNAL(SIGTRAP, bad_signal);
361#endif
362#ifdef SIGVTALRM
363    SIGNAL(SIGVTALRM, bad_signal);
364#endif
365#ifdef SIGXCPU
366    SIGNAL(SIGXCPU, bad_signal);
367#endif
368#ifdef SIGXFSZ
369    SIGNAL(SIGXFSZ, bad_signal);
370#endif
371
372    /*
373     * Apparently we can get a SIGPIPE when we call syslog, if
374     * syslogd has died and been restarted.  Ignoring it seems
375     * be sufficient.
376     */
377    signal(SIGPIPE, SIG_IGN);
378
379    /*
380     * If we're doing dial-on-demand, set up the interface now.
381     */
382    if (demand) {
383	/*
384	 * Open the loopback channel and set it up to be the ppp interface.
385	 */
386	open_ppp_loopback();
387
388	syslog(LOG_INFO, "Using interface ppp%d", ifunit);
389	(void) snprintf(ifname, sizeof ifname, "ppp%d", ifunit);
390	script_setenv("IFNAME", ifname);
391
392	/*
393	 * Configure the interface and mark it up, etc.
394	 */
395	demand_conf();
396    }
397
398    for (;;) {
399
400	need_holdoff = 1;
401
402	if (demand) {
403	    /*
404	     * Don't do anything until we see some activity.
405	     */
406	    phase = PHASE_DORMANT;
407	    kill_link = 0;
408	    demand_unblock();
409	    for (;;) {
410		wait_loop_output(timeleft(&timo));
411		calltimeout();
412		if (kill_link) {
413		    if (!persist)
414			die(0);
415		    kill_link = 0;
416		}
417		if (get_loop_output())
418		    break;
419		reap_kids();
420	    }
421
422	    /*
423	     * Now we want to bring up the link.
424	     */
425	    demand_drop();
426	    syslog(LOG_INFO, "Starting link");
427	}
428
429	/*
430	 * Lock the device if we've been asked to.
431	 */
432	if (lockflag && !default_device) {
433	    if (lock(devnam) < 0)
434		goto fail;
435	    locked = 1;
436	}
437
438	/*
439	 * Open the serial device and set it up to be the ppp interface.
440	 * First we open it in non-blocking mode so we can set the
441	 * various termios flags appropriately.  If we aren't dialling
442	 * out and we want to use the modem lines, we reopen it later
443	 * in order to wait for the carrier detect signal from the modem.
444	 */
445	while ((ttyfd = open(devnam, O_NONBLOCK | O_RDWR, 0)) < 0) {
446	    if (errno != EINTR)
447		syslog(LOG_ERR, "Failed to open %s: %m", devnam);
448	    if (!persist || errno != EINTR)
449		goto fail;
450	}
451	if ((fdflags = fcntl(ttyfd, F_GETFL)) == -1
452	    || fcntl(ttyfd, F_SETFL, fdflags & ~O_NONBLOCK) < 0)
453	    syslog(LOG_WARNING,
454		   "Couldn't reset non-blocking mode on device: %m");
455
456	hungup = 0;
457	kill_link = 0;
458
459	/*
460	 * Do the equivalent of `mesg n' to stop broadcast messages.
461	 */
462	if (fstat(ttyfd, &statbuf) < 0
463	    || fchmod(ttyfd, statbuf.st_mode & ~(S_IWGRP | S_IWOTH)) < 0) {
464	    syslog(LOG_WARNING,
465		   "Couldn't restrict write permissions to %s: %m", devnam);
466	} else
467	    tty_mode = statbuf.st_mode;
468
469	/* run connection script */
470	if (connector && connector[0]) {
471	    MAINDEBUG((LOG_INFO, "Connecting with <%s>", connector));
472
473	    /*
474	     * Set line speed, flow control, etc.
475	     * On most systems we set CLOCAL for now so that we can talk
476	     * to the modem before carrier comes up.  But this has the
477	     * side effect that we might miss it if CD drops before we
478	     * get to clear CLOCAL below.  On systems where we can talk
479	     * successfully to the modem with CLOCAL clear and CD down,
480	     * we can clear CLOCAL at this point.
481	     */
482	    set_up_tty(ttyfd, (modem_chat == 0));
483
484	    /* drop dtr to hang up in case modem is off hook */
485	    if (!default_device && modem) {
486		setdtr(ttyfd, FALSE);
487		sleep(1);
488		setdtr(ttyfd, TRUE);
489	    }
490
491	    if (device_script(connector, ttyfd, ttyfd) < 0) {
492		syslog(LOG_ERR, "Connect script failed");
493		setdtr(ttyfd, FALSE);
494		goto fail;
495	    }
496
497	    syslog(LOG_INFO, "Serial connection established.");
498	    sleep(1);		/* give it time to set up its terminal */
499	}
500
501	set_up_tty(ttyfd, 0);
502
503	/* reopen tty if necessary to wait for carrier */
504	if (connector == NULL && modem) {
505	    while ((i = open(devnam, O_RDWR)) < 0) {
506		if (errno != EINTR)
507		    syslog(LOG_ERR, "Failed to reopen %s: %m", devnam);
508		if (!persist || errno != EINTR || hungup || kill_link)
509		    goto fail;
510	    }
511	    close(i);
512	}
513
514	/* run welcome script, if any */
515	if (welcomer && welcomer[0]) {
516	    if (device_script(welcomer, ttyfd, ttyfd) < 0)
517		syslog(LOG_WARNING, "Welcome script failed");
518	}
519
520	/* set up the serial device as a ppp interface */
521	establish_ppp(ttyfd);
522
523	if (!demand) {
524
525	    syslog(LOG_INFO, "Using interface ppp%d", ifunit);
526	    (void) snprintf(ifname, sizeof ifname, "ppp%d", ifunit);
527	    script_setenv("IFNAME", ifname);
528	}
529
530	/*
531	 * Start opening the connection and wait for
532	 * incoming events (reply, timeout, etc.).
533	 */
534	syslog(LOG_NOTICE, "Connect: %s <--> %s", ifname, devnam);
535	lcp_lowerup(0);
536	lcp_open(0);		/* Start protocol */
537	for (phase = PHASE_ESTABLISH; phase != PHASE_DEAD; ) {
538	    wait_input(timeleft(&timo));
539	    calltimeout();
540	    get_input();
541	    if (kill_link) {
542		lcp_close(0, "User request");
543		kill_link = 0;
544	    }
545	    if (open_ccp_flag) {
546		if (phase == PHASE_NETWORK) {
547		    ccp_fsm[0].flags = OPT_RESTART; /* clears OPT_SILENT */
548		    (*ccp_protent.open)(0);
549		}
550		open_ccp_flag = 0;
551	    }
552	    reap_kids();	/* Don't leave dead kids lying around */
553	}
554
555	/*
556	 * If we may want to bring the link up again, transfer
557	 * the ppp unit back to the loopback.  Set the
558	 * real serial device back to its normal mode of operation.
559	 */
560	clean_check();
561	if (demand)
562	    restore_loop();
563	disestablish_ppp(ttyfd);
564
565	/*
566	 * Run disconnector script, if requested.
567	 * XXX we may not be able to do this if the line has hung up!
568	 */
569	if (disconnector && !hungup) {
570	    set_up_tty(ttyfd, 1);
571	    if (device_script(disconnector, ttyfd, ttyfd) < 0) {
572		syslog(LOG_WARNING, "disconnect script failed");
573	    } else {
574		syslog(LOG_INFO, "Serial link disconnected.");
575	    }
576	}
577
578    fail:
579	if (ttyfd >= 0)
580	    close_tty();
581	if (locked) {
582	    unlock();
583	    locked = 0;
584	}
585
586	if (!persist)
587	    die(1);
588
589	if (holdoff > 0 && need_holdoff) {
590	    phase = PHASE_HOLDOFF;
591	    TIMEOUT(holdoff_end, NULL, holdoff);
592	    do {
593		wait_time(timeleft(&timo));
594		calltimeout();
595		if (kill_link) {
596		    if (!persist)
597			die(0);
598		    kill_link = 0;
599		    phase = PHASE_DORMANT; /* allow signal to end holdoff */
600		}
601		reap_kids();
602	    } while (phase == PHASE_HOLDOFF);
603	}
604    }
605
606    die(0);
607    return 0;
608}
609
610/*
611 * detach - detach us from the controlling terminal.
612 */
613void
614detach()
615{
616    if (detached)
617	return;
618    if (daemon(0, 0) < 0) {
619	perror("Couldn't detach from controlling terminal");
620	die(1);
621    }
622    detached = 1;
623    pid = getpid();
624}
625
626/*
627 * holdoff_end - called via a timeout when the holdoff period ends.
628 */
629static void
630holdoff_end(arg)
631    void *arg;
632{
633    phase = PHASE_DORMANT;
634}
635
636/*
637 * get_input - called when incoming data is available.
638 */
639static void
640get_input()
641{
642    int len, i;
643    u_char *p;
644    u_short protocol;
645    struct protent *protp;
646
647    p = inpacket_buf;	/* point to beginning of packet buffer */
648
649    len = read_packet(inpacket_buf);
650    if (len < 0)
651	return;
652
653    if (len == 0) {
654	syslog(LOG_NOTICE, "Modem hangup");
655	hungup = 1;
656	lcp_lowerdown(0);	/* serial link is no longer available */
657	link_terminated(0);
658	return;
659    }
660
661    if (debug /*&& (debugflags & DBG_INPACKET)*/)
662	log_packet(p, len, "rcvd ", LOG_DEBUG);
663
664    if (len < PPP_HDRLEN) {
665	MAINDEBUG((LOG_INFO, "io(): Received short packet."));
666	return;
667    }
668
669    p += 2;				/* Skip address and control */
670    GETSHORT(protocol, p);
671    len -= PPP_HDRLEN;
672
673    /*
674     * Toss all non-LCP packets unless LCP is OPEN.
675     */
676    if (protocol != PPP_LCP && lcp_fsm[0].state != OPENED) {
677	MAINDEBUG((LOG_INFO,
678		   "get_input: Received non-LCP packet when LCP not open."));
679	return;
680    }
681
682    /*
683     * Until we get past the authentication phase, toss all packets
684     * except LCP, LQR and authentication packets.
685     */
686    if (phase <= PHASE_AUTHENTICATE
687	&& !(protocol == PPP_LCP || protocol == PPP_LQR
688	|| protocol == PPP_PAP || protocol == PPP_CHAP)) {
689	MAINDEBUG((LOG_INFO, "get_input: discarding proto 0x%x in phase %d",
690		   protocol, phase));
691	return;
692    }
693
694    /*
695     * Upcall the proper protocol input routine.
696     */
697    for (i = 0; (protp = protocols[i]) != NULL; ++i) {
698	if (protp->protocol == protocol && protp->enabled_flag) {
699	    (*protp->input)(0, p, len);
700	    return;
701	}
702	if (protocol == (protp->protocol & ~0x8000) && protp->enabled_flag
703	    && protp->datainput != NULL) {
704	    (*protp->datainput)(0, p, len);
705	    return;
706	}
707    }
708
709    if (debug)
710    	syslog(LOG_WARNING, "Unsupported protocol (0x%x) received", protocol);
711    lcp_sprotrej(0, p - PPP_HDRLEN, len + PPP_HDRLEN);
712}
713
714
715/*
716 * quit - Clean up state and exit (with an error indication).
717 */
718void
719quit()
720{
721    die(1);
722}
723
724/*
725 * die - like quit, except we can specify an exit status.
726 */
727void
728die(status)
729    int status;
730{
731    struct syslog_data sdata = SYSLOG_DATA_INIT;
732
733    cleanup();
734    syslog_r(LOG_INFO, &sdata, "Exit.");
735    _exit(status);
736}
737
738/*
739 * cleanup - restore anything which needs to be restored before we exit
740 */
741/* ARGSUSED */
742static void
743cleanup()
744{
745    sys_cleanup();
746
747    if (ttyfd >= 0)
748	close_tty();
749
750    if (locked)
751	unlock();
752}
753
754/*
755 * close_tty - restore the terminal device and close it.
756 */
757static void
758close_tty()
759{
760    disestablish_ppp(ttyfd);
761
762    /* drop dtr to hang up */
763    if (modem) {
764	setdtr(ttyfd, FALSE);
765	/*
766	 * This sleep is in case the serial port has CLOCAL set by default,
767	 * and consequently will reassert DTR when we close the device.
768	 */
769	sleep(1);
770    }
771
772    restore_tty(ttyfd);
773
774    if (tty_mode != (mode_t) -1)
775	fchmod(ttyfd, tty_mode);
776
777    close(ttyfd);
778    ttyfd = -1;
779}
780
781
782struct	callout {
783    struct timeval	c_time;		/* time at which to call routine */
784    void		*c_arg;		/* argument to routine */
785    void		(*c_func)(void *); /* routine */
786    struct		callout *c_next;
787};
788
789static struct callout *callout = NULL;	/* Callout list */
790static struct timeval timenow;		/* Current time */
791
792/*
793 * timeout - Schedule a timeout.
794 *
795 * Note that this timeout takes the number of seconds, NOT hz (as in
796 * the kernel).
797 */
798void
799timeout(func, arg, time)
800    void (*func)(void *);
801    void *arg;
802    int time;
803{
804    struct callout *newp, *p, **pp;
805
806    MAINDEBUG((LOG_DEBUG, "Timeout %lx:%lx in %d seconds.",
807	       (long) func, (long) arg, time));
808
809    /*
810     * Allocate timeout.
811     */
812    if ((newp = (struct callout *) malloc(sizeof(struct callout))) == NULL) {
813	syslog(LOG_ERR, "Out of memory in timeout()!");
814	die(1);
815    }
816    newp->c_arg = arg;
817    newp->c_func = func;
818    gettimeofday(&timenow, NULL);
819    newp->c_time.tv_sec = timenow.tv_sec + time;
820    newp->c_time.tv_usec = timenow.tv_usec;
821
822    /*
823     * Find correct place and link it in.
824     */
825    for (pp = &callout; (p = *pp); pp = &p->c_next)
826	if (newp->c_time.tv_sec < p->c_time.tv_sec
827	    || (newp->c_time.tv_sec == p->c_time.tv_sec
828		&& newp->c_time.tv_usec < p->c_time.tv_sec))
829	    break;
830    newp->c_next = p;
831    *pp = newp;
832}
833
834
835/*
836 * untimeout - Unschedule a timeout.
837 */
838void
839untimeout(func, arg)
840    void (*func)(void *);
841    void *arg;
842{
843    struct callout **copp, *freep;
844
845    MAINDEBUG((LOG_DEBUG, "Untimeout %lx:%lx.", (long) func, (long) arg));
846
847    /*
848     * Find first matching timeout and remove it from the list.
849     */
850    for (copp = &callout; (freep = *copp); copp = &freep->c_next)
851	if (freep->c_func == func && freep->c_arg == arg) {
852	    *copp = freep->c_next;
853	    (void) free((char *) freep);
854	    break;
855	}
856}
857
858
859/*
860 * calltimeout - Call any timeout routines which are now due.
861 */
862static void
863calltimeout()
864{
865    struct callout *p;
866
867    while (callout != NULL) {
868	p = callout;
869
870	if (gettimeofday(&timenow, NULL) < 0) {
871	    syslog(LOG_ERR, "Failed to get time of day: %m");
872	    die(1);
873	}
874	if (!(p->c_time.tv_sec < timenow.tv_sec
875	      || (p->c_time.tv_sec == timenow.tv_sec
876		  && p->c_time.tv_usec <= timenow.tv_usec)))
877	    break;		/* no, it's not time yet */
878
879	callout = p->c_next;
880	(*p->c_func)(p->c_arg);
881
882	free((char *) p);
883    }
884}
885
886
887/*
888 * timeleft - return the length of time until the next timeout is due.
889 */
890static struct timeval *
891timeleft(tvp)
892    struct timeval *tvp;
893{
894    if (callout == NULL)
895	return NULL;
896
897    gettimeofday(&timenow, NULL);
898    tvp->tv_sec = callout->c_time.tv_sec - timenow.tv_sec;
899    tvp->tv_usec = callout->c_time.tv_usec - timenow.tv_usec;
900    if (tvp->tv_usec < 0) {
901	tvp->tv_usec += 1000000;
902	tvp->tv_sec -= 1;
903    }
904    if (tvp->tv_sec < 0)
905	tvp->tv_sec = tvp->tv_usec = 0;
906
907    return tvp;
908}
909
910
911/*
912 * kill_my_pg - send a signal to our process group, and ignore it ourselves.
913 */
914static void
915kill_my_pg(sig)
916    int sig;
917{
918    struct sigaction act, oldact;
919
920    act.sa_handler = SIG_IGN;
921    act.sa_flags = 0;
922    kill(0, sig);
923    sigaction(sig, &act, &oldact);
924    sigaction(sig, &oldact, NULL);
925}
926
927
928/*
929 * hup - Catch SIGHUP signal.
930 *
931 * Indicates that the physical layer has been disconnected.
932 * We don't rely on this indication; if the user has sent this
933 * signal, we just take the link down.
934 */
935static void
936hup(sig)
937    int sig;
938{
939    int save_errno = errno;
940    struct syslog_data sdata = SYSLOG_DATA_INIT;
941
942    if (crashed)
943	_exit(127);
944    syslog_r(LOG_INFO, &sdata, "Hangup (SIGHUP)");
945    kill_link = 1;
946    if (conn_running)
947	/* Send the signal to the [dis]connector process(es) also */
948	kill_my_pg(sig);
949    errno = save_errno;
950}
951
952
953/*
954 * term - Catch SIGTERM signal and SIGINT signal (^C/del).
955 *
956 * Indicates that we should initiate a graceful disconnect and exit.
957 */
958/*ARGSUSED*/
959static void
960term(sig)
961    int sig;
962{
963    int save_errno = errno;
964    struct syslog_data sdata = SYSLOG_DATA_INIT;
965
966    if (crashed)
967	_exit(127);
968    syslog_r(LOG_INFO, &sdata, "Terminating on signal %d.", sig);
969    persist = 0;		/* don't try to restart */
970    kill_link = 1;
971    if (conn_running)
972	/* Send the signal to the [dis]connector process(es) also */
973	kill_my_pg(sig);
974    errno = save_errno;
975}
976
977
978/*
979 * chld - Catch SIGCHLD signal.
980 * Calls reap_kids to get status for any dead kids.
981 */
982static void
983chld(sig)
984    int sig;
985{
986    int save_errno = errno;
987
988    reap_kids();		/* XXX somewhat unsafe */
989    errno = save_errno;
990}
991
992
993/*
994 * toggle_debug - Catch SIGUSR1 signal.
995 *
996 * Toggle debug flag.
997 */
998/*ARGSUSED*/
999static void
1000toggle_debug(sig)
1001    int sig;
1002{
1003    debug = !debug;
1004    if (debug) {
1005	setlogmask(LOG_UPTO(LOG_DEBUG));	/* XXX safe, but wrong */
1006    } else {
1007	setlogmask(LOG_UPTO(LOG_WARNING));	/* XXX safe, but wrong */
1008    }
1009}
1010
1011
1012/*
1013 * open_ccp - Catch SIGUSR2 signal.
1014 *
1015 * Try to (re)negotiate compression.
1016 */
1017/*ARGSUSED*/
1018static void
1019open_ccp(sig)
1020    int sig;
1021{
1022    open_ccp_flag = 1;
1023}
1024
1025
1026/*
1027 * bad_signal - We've caught a fatal signal.  Clean up state and exit.
1028 */
1029static void
1030bad_signal(sig)
1031    int sig;
1032{
1033    struct syslog_data sdata = SYSLOG_DATA_INIT;
1034
1035    if (crashed)
1036	_exit(127);
1037    crashed = 1;
1038    syslog_r(LOG_ERR, &sdata, "Fatal signal %d", sig);
1039    if (conn_running)
1040	kill_my_pg(SIGTERM);
1041    die(1);					/* XXX unsafe! */
1042}
1043
1044
1045/*
1046 * device_script - run a program to connect or disconnect the
1047 * serial device.
1048 */
1049static int
1050device_script(program, in, out)
1051    char *program;
1052    int in, out;
1053{
1054    pid_t pid;
1055    int status;
1056    int errfd;
1057    gid_t gid;
1058    uid_t uid;
1059
1060    conn_running = 1;
1061    pid = fork();
1062
1063    if (pid < 0) {
1064	conn_running = 0;
1065	syslog(LOG_ERR, "Failed to create child process: %m");
1066	die(1);
1067    }
1068
1069    if (pid == 0) {
1070	sys_close();
1071	closelog();
1072	if (in == out) {
1073	    if (in != 0) {
1074		dup2(in, 0);
1075		close(in);
1076	    }
1077	    dup2(0, 1);
1078	} else {
1079	    if (out == 0)
1080		out = dup(out);
1081	    if (in != 0) {
1082		dup2(in, 0);
1083		close(in);
1084	    }
1085	    if (out != 1) {
1086		dup2(out, 1);
1087		close(out);
1088	    }
1089	}
1090	if (nodetach == 0) {
1091	    close(2);
1092	    errfd = open(_PATH_CONNERRS, O_WRONLY | O_APPEND | O_CREAT, 0600);
1093	    if (errfd >= 0 && errfd != 2) {
1094		dup2(errfd, 2);
1095		close(errfd);
1096	    }
1097	}
1098
1099	/* revoke privs */
1100	gid = getgid();
1101	uid = getuid();
1102	if (setresgid(gid, gid, gid) == -1 || setresuid(uid, uid, uid) == -1) {
1103		syslog(LOG_ERR, "revoke privileges: %s", strerror(errno));
1104		_exit(1);
1105	}
1106
1107	execl("/bin/sh", "sh", "-c", program, (char *)0);
1108	syslog(LOG_ERR, "could not exec /bin/sh: %m");
1109	_exit(99);
1110	/* NOTREACHED */
1111    }
1112
1113    while (waitpid(pid, &status, 0) < 0) {
1114	if (errno == EINTR)
1115	    continue;
1116	syslog(LOG_ERR, "error waiting for (dis)connection process: %m");
1117	die(1);
1118    }
1119    conn_running = 0;
1120
1121    return (status == 0 ? 0 : -1);
1122}
1123
1124
1125/*
1126 * run-program - execute a program with given arguments,
1127 * but don't wait for it.
1128 * If the program can't be executed, logs an error unless
1129 * must_exist is 0 and the program file doesn't exist.
1130 */
1131int
1132run_program(prog, args, must_exist)
1133    char *prog;
1134    char **args;
1135    int must_exist;
1136{
1137    pid_t pid;
1138    uid_t uid;
1139    gid_t gid;
1140
1141    pid = fork();
1142    if (pid == -1) {
1143	syslog(LOG_ERR, "Failed to create child process for %s: %m", prog);
1144	return -1;
1145    }
1146    if (pid == 0) {
1147	int new_fd;
1148
1149	/* Leave the current location */
1150	(void) setsid();    /* No controlling tty. */
1151	(void) umask (S_IRWXG|S_IRWXO);
1152	(void) chdir ("/"); /* no current directory. */
1153
1154	/* revoke privs */
1155	uid = getuid();
1156	gid = getgid();
1157	if (setresgid(gid, gid, gid) == -1 || setresuid(uid, uid, uid) == -1) {
1158		syslog(LOG_ERR, "revoke privileges: %s", strerror(errno));
1159		_exit(1);
1160	}
1161
1162	/* Ensure that nothing of our device environment is inherited. */
1163	sys_close();
1164	closelog();
1165	close (0);
1166	close (1);
1167	close (2);
1168	close (ttyfd);  /* tty interface to the ppp device */
1169
1170	/* Don't pass handles to the PPP device, even by accident. */
1171	new_fd = open (_PATH_DEVNULL, O_RDWR);
1172	if (new_fd >= 0) {
1173	    if (new_fd != 0) {
1174		dup2  (new_fd, 0); /* stdin <- /dev/null */
1175		close (new_fd);
1176	    }
1177	    dup2 (0, 1); /* stdout -> /dev/null */
1178	    dup2 (0, 2); /* stderr -> /dev/null */
1179	}
1180
1181	/* Force the priority back to zero if pppd is running higher. */
1182	if (setpriority (PRIO_PROCESS, 0, 0) < 0)
1183	    syslog (LOG_WARNING, "can't reset priority to 0: %m");
1184
1185	/* SysV recommends a second fork at this point. */
1186
1187	/* run the program; give it a null environment */
1188	execve(prog, args, script_env);
1189	if (must_exist || errno != ENOENT)
1190	    syslog(LOG_WARNING, "Can't execute %s: %m", prog);
1191	_exit(1);
1192    }
1193    MAINDEBUG((LOG_DEBUG, "Script %s started; pid = %ld", prog, (long)pid));
1194    ++n_children;
1195    return 0;
1196}
1197
1198
1199/*
1200 * reap_kids - get status from any dead child processes,
1201 * and log a message for abnormal terminations.
1202 */
1203static void
1204reap_kids()
1205{
1206    int status;
1207    pid_t pid;
1208
1209    if (n_children == 0)
1210	return;
1211    if ((pid = waitpid(-1, &status, WNOHANG)) == -1) {
1212	if (errno != ECHILD)
1213	    syslog(LOG_ERR, "Error waiting for child process: %m");
1214	return;
1215    }
1216    if (pid > 0) {
1217	--n_children;
1218	if (WIFSIGNALED(status)) {
1219	    syslog(LOG_WARNING, "Child process %ld terminated with signal %d",
1220		   (long)pid, WTERMSIG(status));
1221	}
1222    }
1223}
1224
1225
1226/*
1227 * log_packet - format a packet and log it.
1228 */
1229
1230char line[256];			/* line to be logged accumulated here */
1231char *linep;
1232
1233void
1234log_packet(p, len, prefix, level)
1235    u_char *p;
1236    int len;
1237    char *prefix;
1238    int level;
1239{
1240    strlcpy(line, prefix, sizeof line);
1241    linep = line + strlen(line);
1242    format_packet(p, len, pr_log, NULL);
1243    if (linep != line)
1244	syslog(level, "%s", line);
1245}
1246
1247/*
1248 * format_packet - make a readable representation of a packet,
1249 * calling `printer(arg, format, ...)' to output it.
1250 */
1251void
1252format_packet(p, len, printer, arg)
1253    u_char *p;
1254    int len;
1255    void (*printer)(void *, char *, ...);
1256    void *arg;
1257{
1258    int i, n;
1259    u_short proto;
1260    u_char x;
1261    struct protent *protp;
1262
1263    if (len >= PPP_HDRLEN && p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) {
1264	p += 2;
1265	GETSHORT(proto, p);
1266	len -= PPP_HDRLEN;
1267	for (i = 0; (protp = protocols[i]) != NULL; ++i)
1268	    if (proto == protp->protocol)
1269		break;
1270	if (protp != NULL) {
1271	    printer(arg, "[%s", protp->name);
1272	    n = (*protp->printpkt)(p, len, printer, arg);
1273	    printer(arg, "]");
1274	    p += n;
1275	    len -= n;
1276	} else {
1277	    printer(arg, "[proto=0x%x]", proto);
1278	}
1279    }
1280
1281    for (; len > 0; --len) {
1282	GETCHAR(x, p);
1283	printer(arg, " %.2x", x);
1284    }
1285}
1286
1287static void
1288pr_log(void *arg, char *fmt, ...)
1289{
1290    int n;
1291    va_list pvar;
1292    char buf[256];
1293
1294    va_start(pvar, fmt);
1295
1296    n = vfmtmsg(buf, sizeof(buf), fmt, pvar);
1297    va_end(pvar);
1298
1299    if (linep + n + 1 > line + sizeof(line)) {
1300	syslog(LOG_DEBUG, "%s", line);
1301	linep = line;
1302    }
1303    strlcpy(linep, buf, line + sizeof line - linep);
1304    linep += n;
1305}
1306
1307/*
1308 * print_string - print a readable representation of a string using
1309 * printer.
1310 */
1311void
1312print_string(p, len, printer, arg)
1313    char *p;
1314    int len;
1315    void (*printer)(void *, char *, ...);
1316    void *arg;
1317{
1318    int c;
1319
1320    printer(arg, "\"");
1321    for (; len > 0; --len) {
1322	c = *p++;
1323	if (' ' <= c && c <= '~') {
1324	    if (c == '\\' || c == '"')
1325		printer(arg, "\\");
1326	    printer(arg, "%c", c);
1327	} else {
1328	    switch (c) {
1329	    case '\n':
1330		printer(arg, "\\n");
1331		break;
1332	    case '\r':
1333		printer(arg, "\\r");
1334		break;
1335	    case '\t':
1336		printer(arg, "\\t");
1337		break;
1338	    default:
1339		printer(arg, "\\%.3o", c);
1340	    }
1341	}
1342    }
1343    printer(arg, "\"");
1344}
1345
1346/*
1347 * novm - log an error message saying we ran out of memory, and die.
1348 */
1349void
1350novm(msg)
1351    char *msg;
1352{
1353    syslog(LOG_ERR, "Virtual memory exhausted allocating %s", msg);
1354    die(1);
1355}
1356
1357/*
1358 * fmtmsg - format a message into a buffer.  Like snprintf except we
1359 * also specify the length of the output buffer, and we handle
1360 * %m (error message) and %I (IP address) formats.
1361 * Doesn't do floating-point formats.
1362 * Returns the number of chars put into buf.
1363 */
1364int
1365fmtmsg(char *buf, int buflen, char *fmt, ...)
1366{
1367    va_list args;
1368    int n;
1369
1370    va_start(args, fmt);
1371    n = vfmtmsg(buf, buflen, fmt, args);
1372    va_end(args);
1373    return n;
1374}
1375
1376/*
1377 * vfmtmsg - like fmtmsg, takes a va_list instead of a list of args.
1378 */
1379#define OUTCHAR(c)	(buflen > 0? (--buflen, *buf++ = (c)): 0)
1380
1381int
1382vfmtmsg(buf, buflen, fmt, args)
1383    char *buf;
1384    int buflen;
1385    char *fmt;
1386    va_list args;
1387{
1388    int c, i, n;
1389    int width, prec, fillch;
1390    int base, len, neg, quoted;
1391    unsigned long val = 0;
1392    char *str, *f, *buf0;
1393    unsigned char *p;
1394    char num[32];
1395    time_t t;
1396    static char hexchars[] = "0123456789abcdef";
1397
1398    buf0 = buf;
1399    --buflen;
1400    while (buflen > 0) {
1401	for (f = fmt; *f != '%' && *f != 0; ++f)
1402	    ;
1403	if (f > fmt) {
1404	    len = f - fmt;
1405	    if (len > buflen)
1406		len = buflen;
1407	    memcpy(buf, fmt, len);
1408	    buf += len;
1409	    buflen -= len;
1410	    fmt = f;
1411	}
1412	if (*fmt == 0)
1413	    break;
1414	c = *++fmt;
1415	width = prec = 0;
1416	fillch = ' ';
1417	if (c == '0') {
1418	    fillch = '0';
1419	    c = *++fmt;
1420	}
1421	if (c == '*') {
1422	    width = va_arg(args, int);
1423	    c = *++fmt;
1424	} else {
1425	    while (isdigit(c)) {
1426		width = width * 10 + c - '0';
1427		c = *++fmt;
1428	    }
1429	}
1430	if (c == '.') {
1431	    c = *++fmt;
1432	    if (c == '*') {
1433		prec = va_arg(args, int);
1434		c = *++fmt;
1435	    } else {
1436		while (isdigit(c)) {
1437		    prec = prec * 10 + c - '0';
1438		    c = *++fmt;
1439		}
1440	    }
1441	}
1442	str = 0;
1443	base = 0;
1444	neg = 0;
1445	++fmt;
1446	switch (c) {
1447	case 'd':
1448	    i = va_arg(args, int);
1449	    if (i < 0) {
1450		neg = 1;
1451		val = -i;
1452	    } else
1453		val = i;
1454	    base = 10;
1455	    break;
1456	case 'o':
1457	    val = va_arg(args, unsigned int);
1458	    base = 8;
1459	    break;
1460	case 'x':
1461	    val = va_arg(args, unsigned int);
1462	    base = 16;
1463	    break;
1464	case 'p':
1465	    val = (unsigned long) va_arg(args, void *);
1466	    base = 16;
1467	    neg = 2;
1468	    break;
1469	case 's':
1470	    str = va_arg(args, char *);
1471	    break;
1472	case 'c':
1473	    num[0] = va_arg(args, int);
1474	    num[1] = 0;
1475	    str = num;
1476	    break;
1477	case 'm':
1478	    str = strerror(errno);
1479	    break;
1480	case 'I':
1481	    str = ip_ntoa(va_arg(args, u_int32_t));
1482	    break;
1483	case 't':
1484	    time(&t);
1485	    str = ctime(&t);
1486	    str += 4;		/* chop off the day name */
1487	    str[15] = 0;	/* chop off year and newline */
1488	    break;
1489	case 'v':		/* "visible" string */
1490	case 'q':		/* quoted string */
1491	    quoted = c == 'q';
1492	    p = va_arg(args, unsigned char *);
1493	    if (fillch == '0' && prec > 0) {
1494		n = prec;
1495	    } else {
1496		n = strlen((char *)p);
1497		if (prec > 0 && prec < n)
1498		    n = prec;
1499	    }
1500	    while (n > 0 && buflen > 0) {
1501		c = *p++;
1502		--n;
1503		if (!quoted && c >= 0x80) {
1504		    OUTCHAR('M');
1505		    OUTCHAR('-');
1506		    c -= 0x80;
1507		}
1508		if (quoted && (c == '"' || c == '\\'))
1509		    OUTCHAR('\\');
1510		if (c < 0x20 || (0x7f <= c && c < 0xa0)) {
1511		    if (quoted) {
1512			OUTCHAR('\\');
1513			switch (c) {
1514			case '\t':	OUTCHAR('t');	break;
1515			case '\n':	OUTCHAR('n');	break;
1516			case '\b':	OUTCHAR('b');	break;
1517			case '\f':	OUTCHAR('f');	break;
1518			default:
1519			    OUTCHAR('x');
1520			    OUTCHAR(hexchars[c >> 4]);
1521			    OUTCHAR(hexchars[c & 0xf]);
1522			}
1523		    } else {
1524			if (c == '\t')
1525			    OUTCHAR(c);
1526			else {
1527			    OUTCHAR('^');
1528			    OUTCHAR(c ^ 0x40);
1529			}
1530		    }
1531		} else
1532		    OUTCHAR(c);
1533	    }
1534	    continue;
1535	default:
1536	    *buf++ = '%';
1537	    if (c != '%')
1538		--fmt;		/* so %z outputs %z etc. */
1539	    --buflen;
1540	    continue;
1541	}
1542	if (base != 0) {
1543	    str = num + sizeof(num);
1544	    *--str = 0;
1545	    while (str > num + neg) {
1546		*--str = hexchars[val % base];
1547		val = val / base;
1548		if (--prec <= 0 && val == 0)
1549		    break;
1550	    }
1551	    switch (neg) {
1552	    case 1:
1553		*--str = '-';
1554		break;
1555	    case 2:
1556		*--str = 'x';
1557		*--str = '0';
1558		break;
1559	    }
1560	    len = num + sizeof(num) - 1 - str;
1561	} else {
1562	    len = strlen(str);
1563	    if (prec > 0 && len > prec)
1564		len = prec;
1565	}
1566	if (width > 0) {
1567	    if (width > buflen)
1568		width = buflen;
1569	    if ((n = width - len) > 0) {
1570		buflen -= n;
1571		for (; n > 0; --n)
1572		    *buf++ = fillch;
1573	    }
1574	}
1575	if (len > buflen)
1576	    len = buflen;
1577	memcpy(buf, str, len);
1578	buf += len;
1579	buflen -= len;
1580    }
1581    *buf = 0;
1582    return buf - buf0;
1583}
1584
1585/*
1586 * script_setenv - set an environment variable value to be used
1587 * for scripts that we run (e.g. ip-up, auth-up, etc.)
1588 */
1589void
1590script_setenv(var, value)
1591    char *var, *value;
1592{
1593    int vl = strlen(var);
1594    int i;
1595    char *p, *newstring;
1596
1597    if (asprintf(&newstring, "%s=%s", var, value) == -1)
1598	novm("script_setenv");
1599
1600    /* check if this variable is already set */
1601    if (script_env != 0) {
1602	for (i = 0; (p = script_env[i]) != 0; ++i) {
1603	    if (strncmp(p, var, vl) == 0 && p[vl] == '=') {
1604		free(p);
1605		script_env[i] = newstring;
1606		return;
1607	    }
1608	}
1609    } else {
1610	i = 0;
1611	script_env = (char **) calloc(16, sizeof(char *));
1612	if (script_env == 0)
1613	    novm("script_setenv");
1614	s_env_nalloc = 16;
1615    }
1616
1617    /* reallocate script_env with more space if needed */
1618    if (i + 1 >= s_env_nalloc) {
1619	int new_n = i + 17;
1620	char **newenv = reallocarray(script_env,
1621	    new_n, sizeof(char *));
1622	if (newenv == 0)
1623	    novm("script_setenv");
1624	script_env = newenv;
1625	s_env_nalloc = new_n;
1626    }
1627
1628    script_env[i] = newstring;
1629    script_env[i+1] = 0;
1630}
1631