main.c revision 1.16 
1/*	$OpenBSD: main.c,v 1.16 1997/07/25 20:12:16 mickey Exp $	*/
2
3/*
4 * main.c - Point-to-Point Protocol main module
5 *
6 * Copyright (c) 1989 Carnegie Mellon University.
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms are permitted
10 * provided that the above copyright notice and this paragraph are
11 * duplicated in all such forms and that any documentation,
12 * advertising materials, and other materials related to such
13 * distribution and use acknowledge that the software was developed
14 * by Carnegie Mellon University.  The name of the
15 * University may not be used to endorse or promote products derived
16 * from this software without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
19 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20 */
21
22#ifndef lint
23static char rcsid[] = "$OpenBSD: main.c,v 1.16 1997/07/25 20:12:16 mickey Exp $";
24#endif
25
26#include <stdio.h>
27#include <stdlib.h>
28#include <string.h>
29#include <unistd.h>
30#include <signal.h>
31#include <errno.h>
32#include <fcntl.h>
33#include <syslog.h>
34#include <netdb.h>
35#include <utmp.h>
36#include <pwd.h>
37#include <sys/param.h>
38#include <sys/types.h>
39#include <sys/wait.h>
40#include <sys/time.h>
41#include <sys/resource.h>
42#include <sys/stat.h>
43#include <sys/socket.h>
44#include <net/if.h>
45
46#include "pppd.h"
47#include "magic.h"
48#include "fsm.h"
49#include "lcp.h"
50#include "ipcp.h"
51#include "upap.h"
52#include "chap.h"
53#include "ccp.h"
54#include "pathnames.h"
55#include "patchlevel.h"
56
57#ifdef CBCP_SUPPORT
58#include "cbcp.h"
59#endif
60
61#if defined(SUNOS4)
62extern char *strerror();
63#endif
64
65#ifdef IPX_CHANGE
66#include "ipxcp.h"
67#endif /* IPX_CHANGE */
68
69/* interface vars */
70char ifname[IFNAMSIZ];		/* Interface name */
71int ifunit;			/* Interface unit number */
72
73char *progname;			/* Name of this program */
74char hostname[MAXNAMELEN];	/* Our hostname */
75static char pidfilename[MAXPATHLEN];	/* name of pid file */
76static char default_devnam[MAXPATHLEN];	/* name of default device */
77static pid_t pid;		/* Our pid */
78static uid_t uid;		/* Our real user-id */
79static int conn_running;	/* we have a [dis]connector running */
80
81int ttyfd = -1;			/* Serial port file descriptor */
82mode_t tty_mode = -1;           /* Original access permissions to tty */
83int baud_rate;                  /* Actual bits/second for serial device */
84int hungup;                     /* terminal has been hung up */
85int privileged;			/* we're running as real uid root */
86int need_holdoff;		/* need holdoff period before restarting */
87
88int phase;			/* where the link is at */
89int kill_link;
90int open_ccp_flag;
91int redirect_stderr;          /* Connector's stderr should go to file */
92
93u_char outpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for outgoing packet */
94u_char inpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for incoming packet */
95
96static int n_children;		/* # child processes still running */
97
98static int locked;		/* lock() has succeeded */
99
100char *no_ppp_msg = "Sorry - this system lacks PPP kernel support\n";
101
102/* Prototypes for procedures local to this file. */
103
104static void cleanup __P((void));
105static void close_tty __P((void));
106static void get_input __P((void));
107static void connect_time_expired __P((caddr_t));
108static void calltimeout __P((void));
109static struct timeval *timeleft __P((struct timeval *));
110static void hup __P((int));
111static void term __P((int));
112static void chld __P((int));
113static void toggle_debug __P((int));
114static void open_ccp __P((int));
115static void bad_signal __P((int));
116static void holdoff_end __P((void *));
117static int device_script __P((char *, int, int));
118static void reap_kids __P((void));
119static void pr_log __P((void *, char *, ...));
120
121extern	char	*ttyname __P((int));
122extern	char	*getlogin __P((void));
123
124#ifdef ultrix
125#undef	O_NONBLOCK
126#define	O_NONBLOCK	O_NDELAY
127#endif
128
129#ifdef ULTRIX
130#define setlogmask(x)
131#endif
132
133/*
134 * PPP Data Link Layer "protocol" table.
135 * One entry per supported protocol.
136 * The last entry must be NULL.
137 */
138struct protent *protocols[] = {
139    &lcp_protent,
140    &pap_protent,
141    &chap_protent,
142#ifdef CBCP_SUPPORT
143    &cbcp_protent,
144#endif
145    &ipcp_protent,
146    &ccp_protent,
147#ifdef IPX_CHANGE
148    &ipxcp_protent,
149#endif
150    NULL
151};
152
153int
154main(argc, argv)
155    int argc;
156    char *argv[];
157{
158    int i, nonblock, fdflags;
159    struct sigaction sa;
160    FILE *pidfile;
161    char *p;
162    struct passwd *pw;
163    struct timeval timo;
164    sigset_t mask;
165    struct protent *protp;
166    struct stat statbuf;
167
168    phase = PHASE_INITIALIZE;
169    p = ttyname(0);
170    if (p)
171	strcpy(devnam, p);
172    strcpy(default_devnam, devnam);
173
174    /* Initialize syslog facilities */
175#ifdef ULTRIX
176    openlog("pppd", LOG_PID);
177#else
178    openlog("pppd", LOG_PID | LOG_NDELAY, LOG_PPP);
179    setlogmask(LOG_UPTO(LOG_INFO));
180#endif
181
182    if (gethostname(hostname, MAXNAMELEN) < 0 ) {
183	option_error("Couldn't get hostname: %m");
184	die(1);
185    }
186    hostname[MAXNAMELEN-1] = 0;
187
188    uid = getuid();
189    privileged = uid == 0;
190
191    /*
192     * Initialize to the standard option set, then parse, in order,
193     * the system options file, the user's options file,
194     * the tty's options file, and the command line arguments.
195     */
196    for (i = 0; (protp = protocols[i]) != NULL; ++i)
197        (*protp->init)(0);
198
199    progname = *argv;
200
201    if (!options_from_file(_PATH_SYSOPTIONS, !privileged, 0, 1)
202        || !options_from_user())
203        exit(1);
204    scan_args(argc-1, argv+1);  /* look for tty name on command line */
205    if (!options_for_tty()
206        || !parse_args(argc-1, argv+1))
207	exit(1);
208
209    if (!ppp_available()) {
210	option_error(no_ppp_msg);
211	exit(1);
212    }
213
214    /*
215     * Check that we are running as root.
216     */
217    if (geteuid() != 0) {
218	option_error("must be root to run %s, since it is not setuid-root",
219		     argv[0]);
220	die(1);
221    }
222
223    /*
224     * Check that the options given are valid and consistent.
225     */
226    sys_check_options();
227    auth_check_options();
228    for (i = 0; (protp = protocols[i]) != NULL; ++i)
229	if (protp->check_options != NULL)
230	    (*protp->check_options)();
231    if (demand && connector == 0) {
232	option_error("connect script required for demand-dialling\n");
233	exit(1);
234    }
235
236    /*
237     * If the user has specified the default device name explicitly,
238     * pretend they hadn't.
239     */
240    if (!default_device && strcmp(devnam, default_devnam) == 0)
241	default_device = 1;
242    redirect_stderr = !nodetach || default_device;
243
244
245    /*
246     * Initialize system-dependent stuff and magic number package.
247     */
248    sys_init();
249    magic_init();
250    if (debug)
251      setlogmask(LOG_UPTO(LOG_DEBUG));
252
253
254    /*
255     * Detach ourselves from the terminal, if required,
256     * and identify who is running us.
257     */
258    if (!default_device && !nodetach && daemon(0, 0) < 0) {
259	perror("Couldn't detach from controlling terminal");
260	exit(1);
261    }
262    pid = getpid();
263    p = getlogin();
264    if (p == NULL) {
265	pw = getpwuid(uid);
266	if (pw != NULL && pw->pw_name != NULL)
267	    p = pw->pw_name;
268	else
269	    p = "(unknown)";
270    }
271    syslog(LOG_NOTICE, "pppd %s.%d started by %s, uid %d",
272	   VERSION, PATCHLEVEL, p, uid);
273
274    /*
275     * Compute mask of all interesting signals and install signal handlers
276     * for each.  Only one signal handler may be active at a time.  Therefore,
277     * all other signals should be masked when any handler is executing.
278     */
279    sigemptyset(&mask);
280    sigaddset(&mask, SIGHUP);
281    sigaddset(&mask, SIGINT);
282    sigaddset(&mask, SIGTERM);
283    sigaddset(&mask, SIGCHLD);
284
285#define SIGNAL(s, handler)	{ \
286	sa.sa_handler = handler; \
287	if (sigaction(s, &sa, NULL) < 0) { \
288	    syslog(LOG_ERR, "Couldn't establish signal handler (%d): %m", s); \
289	    die(1); \
290	} \
291    }
292
293    sa.sa_mask = mask;
294    sa.sa_flags = 0;
295    SIGNAL(SIGHUP, hup);		/* Hangup */
296    SIGNAL(SIGINT, term);		/* Interrupt */
297    SIGNAL(SIGTERM, term);		/* Terminate */
298    SIGNAL(SIGCHLD, chld);
299
300    SIGNAL(SIGUSR1, toggle_debug);	/* Toggle debug flag */
301    SIGNAL(SIGUSR2, open_ccp);		/* Reopen CCP */
302
303    /*
304     * Install a handler for other signals which would otherwise
305     * cause pppd to exit without cleaning up.
306     */
307    SIGNAL(SIGABRT, bad_signal);
308    SIGNAL(SIGALRM, bad_signal);
309    SIGNAL(SIGFPE, bad_signal);
310    SIGNAL(SIGILL, bad_signal);
311    SIGNAL(SIGPIPE, bad_signal);
312    SIGNAL(SIGQUIT, bad_signal);
313    SIGNAL(SIGSEGV, bad_signal);
314#ifdef SIGBUS
315    SIGNAL(SIGBUS, bad_signal);
316#endif
317#ifdef SIGEMT
318    SIGNAL(SIGEMT, bad_signal);
319#endif
320#ifdef SIGPOLL
321    SIGNAL(SIGPOLL, bad_signal);
322#endif
323#ifdef SIGPROF
324    SIGNAL(SIGPROF, bad_signal);
325#endif
326#ifdef SIGSYS
327    SIGNAL(SIGSYS, bad_signal);
328#endif
329#ifdef SIGTRAP
330    SIGNAL(SIGTRAP, bad_signal);
331#endif
332#ifdef SIGVTALRM
333    SIGNAL(SIGVTALRM, bad_signal);
334#endif
335#ifdef SIGXCPU
336    SIGNAL(SIGXCPU, bad_signal);
337#endif
338#ifdef SIGXFSZ
339    SIGNAL(SIGXFSZ, bad_signal);
340#endif
341
342    /*
343     * Apparently we can get a SIGPIPE when we call syslog, if
344     * syslogd has died and been restarted.  Ignoring it seems
345     * be sufficient.
346     */
347    signal(SIGPIPE, SIG_IGN);
348
349    /*
350     * If we're doing dial-on-demand, set up the interface now.
351     */
352    if (demand) {
353	/*
354	 * Open the loopback channel and set it up to be the ppp interface.
355	 */
356	open_ppp_loopback();
357
358	syslog(LOG_INFO, "Using interface ppp%d", ifunit);
359	(void) sprintf(ifname, "ppp%d", ifunit);
360
361	/* write pid to file */
362	(void) sprintf(pidfilename, "%s%s.pid", _PATH_VARRUN, ifname);
363	if ((pidfile = fopen(pidfilename, "w")) != NULL) {
364	    fprintf(pidfile, "%d\n", pid);
365	    (void) fclose(pidfile);
366	} else {
367	    syslog(LOG_ERR, "Failed to create pid file %s: %m", pidfilename);
368	    pidfilename[0] = 0;
369	}
370
371	/*
372	 * Configure the interface and mark it up, etc.
373	 */
374	demand_conf();
375    }
376
377    for (;;) {
378
379	need_holdoff = 1;
380
381	if (demand) {
382	    /*
383	     * Don't do anything until we see some activity.
384	     */
385	    phase = PHASE_DORMANT;
386	    kill_link = 0;
387	    demand_unblock();
388	    for (;;) {
389		wait_loop_output(timeleft(&timo));
390		calltimeout();
391		if (kill_link) {
392		    if (!persist)
393			die(0);
394		    kill_link = 0;
395		}
396		if (get_loop_output())
397		    break;
398		reap_kids();
399	    }
400
401	    /*
402	     * Now we want to bring up the link.
403	     */
404	    demand_block();
405	    syslog(LOG_INFO, "Starting link");
406	}
407
408	/*
409	 * Lock the device if we've been asked to.
410	 */
411	if (lockflag && !default_device) {
412	    if (lock(devnam) < 0)
413		goto fail;
414	    locked = 1;
415	}
416
417	/*
418	 * Open the serial device and set it up to be the ppp interface.
419	 * If we're dialling out, or we don't want to use the modem lines,
420	 * we open it in non-blocking mode, but then we need to clear
421	 * the non-blocking I/O bit.
422	 */
423	nonblock = (connector || !modem)? O_NONBLOCK: 0;
424	if ((ttyfd = open(devnam, nonblock | O_RDWR, 0)) < 0) {
425	    syslog(LOG_ERR, "Failed to open %s: %m", devnam);
426	    goto fail;
427	}
428	if (nonblock) {
429	    if ((fdflags = fcntl(ttyfd, F_GETFL)) == -1
430		|| fcntl(ttyfd, F_SETFL, fdflags & ~O_NONBLOCK) < 0)
431		syslog(LOG_WARNING,
432		       "Couldn't reset non-blocking mode on device: %m");
433	}
434	hungup = 0;
435	kill_link = 0;
436
437        /*
438         * Do the equivalent of `mesg n' to stop broadcast messages.
439         */
440        if (fstat(ttyfd, &statbuf) < 0
441            || fchmod(ttyfd, statbuf.st_mode & ~(S_IWGRP | S_IWOTH)) < 0) {
442            syslog(LOG_WARNING,
443                   "Couldn't restrict write permissions to %s: %m", devnam);
444        } else
445            tty_mode = statbuf.st_mode;
446
447	/* run connection script */
448	if (connector && connector[0]) {
449	    MAINDEBUG((LOG_INFO, "Connecting with <%s>", connector));
450
451	    /* set line speed, flow control, etc.; set CLOCAL for now */
452	    set_up_tty(ttyfd, 1);
453
454	    /* drop dtr to hang up in case modem is off hook */
455	    if (!default_device && modem) {
456		setdtr(ttyfd, FALSE);
457		sleep(1);
458		setdtr(ttyfd, TRUE);
459	    }
460
461	    if (device_script(connector, ttyfd, ttyfd) < 0) {
462		syslog(LOG_ERR, "Connect script failed");
463		setdtr(ttyfd, FALSE);
464		goto fail;
465	    }
466
467	    syslog(LOG_INFO, "Serial connection established.");
468	    sleep(1);		/* give it time to set up its terminal */
469	}
470
471	/* set line speed, flow control, etc.; clear CLOCAL if modem option */
472	set_up_tty(ttyfd, 0);
473
474	/* run welcome script, if any */
475	if (welcomer && welcomer[0]) {
476	    if (device_script(welcomer, ttyfd, ttyfd) < 0)
477		syslog(LOG_WARNING, "Welcome script failed");
478	}
479
480	/* set up the serial device as a ppp interface */
481	establish_ppp(ttyfd);
482
483	if (!demand) {
484
485	    syslog(LOG_INFO, "Using interface ppp%d", ifunit);
486	    (void) sprintf(ifname, "ppp%d", ifunit);
487
488	    /* write pid to file */
489	    (void) sprintf(pidfilename, "%s%s.pid", _PATH_VARRUN, ifname);
490	    if ((pidfile = fopen(pidfilename, "w")) != NULL) {
491		fprintf(pidfile, "%d\n", pid);
492		(void) fclose(pidfile);
493	    } else {
494		syslog(LOG_ERR, "Failed to create pid file %s: %m",
495		       pidfilename);
496		pidfilename[0] = 0;
497	    }
498	}
499
500	/*
501	 * Set a timeout to close the connection once the maximum
502	 * connect time has expired.
503	 */
504	if (maxconnect > 0)
505	    TIMEOUT(connect_time_expired, 0, maxconnect);
506
507	/*
508	 * Start opening the connection and wait for
509	 * incoming events (reply, timeout, etc.).
510	 */
511	syslog(LOG_NOTICE, "Connect: %s <--> %s", ifname, devnam);
512	lcp_lowerup(0);
513	lcp_open(0);		/* Start protocol */
514	for (phase = PHASE_ESTABLISH; phase != PHASE_DEAD; ) {
515	    wait_input(timeleft(&timo));
516	    calltimeout();
517	    get_input();
518	    if (kill_link) {
519		lcp_close(0, "User request");
520		kill_link = 0;
521	    }
522	    if (open_ccp_flag) {
523		if (phase == PHASE_NETWORK) {
524		    ccp_fsm[0].flags = OPT_RESTART; /* clears OPT_SILENT */
525                    (*ccp_protent.open)(0);
526		}
527		open_ccp_flag = 0;
528	    }
529	    reap_kids();	/* Don't leave dead kids lying around */
530	}
531
532	/*
533	 * If we may want to bring the link up again, transfer
534	 * the ppp unit back to the loopback.  Set the
535	 * real serial device back to its normal mode of operation.
536	 */
537	clean_check();
538	if (demand)
539	    restore_loop();
540	disestablish_ppp(ttyfd);
541
542	/*
543	 * Run disconnector script, if requested.
544	 * XXX we may not be able to do this if the line has hung up!
545	 */
546	if (disconnector && !hungup) {
547	    set_up_tty(ttyfd, 1);
548	    if (device_script(disconnector, ttyfd, ttyfd) < 0) {
549		syslog(LOG_WARNING, "disconnect script failed");
550	    } else {
551		syslog(LOG_INFO, "Serial link disconnected.");
552	    }
553	}
554
555    fail:
556	close_tty();
557	if (locked) {
558	    unlock();
559	    locked = 0;
560	}
561
562	if (!demand) {
563            if (pidfilename[0] != 0
564                && unlink(pidfilename) < 0 && errno != ENOENT)
565		syslog(LOG_WARNING, "unable to delete pid file: %m");
566	    pidfilename[0] = 0;
567	}
568
569	if (!persist)
570	    break;
571
572	if (demand)
573	    demand_discard();
574	if (holdoff > 0 && need_holdoff) {
575	    phase = PHASE_HOLDOFF;
576	    TIMEOUT(holdoff_end, NULL, holdoff);
577	    do {
578		wait_time(timeleft(&timo));
579		calltimeout();
580		if (kill_link) {
581		    if (!persist)
582			die(0);
583		    kill_link = 0;
584		    phase = PHASE_DORMANT; /* allow signal to end holdoff */
585		}
586		reap_kids();
587	    } while (phase == PHASE_HOLDOFF);
588	}
589    }
590
591    die(0);
592}
593
594/*
595 * holdoff_end - called via a timeout when the holdoff period ends.
596 */
597static void
598holdoff_end(arg)
599    void *arg;
600{
601    phase = PHASE_DORMANT;
602}
603
604/*
605 * get_input - called when incoming data is available.
606 */
607static void
608get_input()
609{
610    int len, i;
611    u_char *p;
612    u_short protocol;
613    struct protent *protp;
614
615    p = inpacket_buf;	/* point to beginning of packet buffer */
616
617    len = read_packet(inpacket_buf);
618    if (len < 0)
619	return;
620
621    if (len == 0) {
622	syslog(LOG_NOTICE, "Modem hangup");
623	hungup = 1;
624	lcp_lowerdown(0);	/* serial link is no longer available */
625	link_terminated(0);
626	return;
627    }
628
629    if (debug /*&& (debugflags & DBG_INPACKET)*/)
630	log_packet(p, len, "rcvd ");
631
632    if (len < PPP_HDRLEN) {
633	MAINDEBUG((LOG_INFO, "io(): Received short packet."));
634	return;
635    }
636
637    p += 2;				/* Skip address and control */
638    GETSHORT(protocol, p);
639    len -= PPP_HDRLEN;
640
641    /*
642     * Toss all non-LCP packets unless LCP is OPEN.
643     */
644    if (protocol != PPP_LCP && lcp_fsm[0].state != OPENED) {
645	MAINDEBUG((LOG_INFO,
646		   "io(): Received non-LCP packet when LCP not open."));
647	return;
648    }
649
650    /*
651     * Upcall the proper protocol input routine.
652     */
653    for (i = 0; (protp = protocols[i]) != NULL; ++i) {
654	if (protp->protocol == protocol && protp->enabled_flag) {
655	    (*protp->input)(0, p, len);
656	    return;
657	}
658        if (protocol == (protp->protocol & ~0x8000) && protp->enabled_flag
659	    && protp->datainput != NULL) {
660	    (*protp->datainput)(0, p, len);
661	    return;
662	}
663    }
664
665    if (debug)
666    	syslog(LOG_WARNING, "Unsupported protocol (0x%x) received", protocol);
667    lcp_sprotrej(0, p - PPP_HDRLEN, len + PPP_HDRLEN);
668}
669
670
671/*
672 * quit - Clean up state and exit (with an error indication).
673 */
674void
675quit()
676{
677    die(1);
678}
679
680/*
681 * die - like quit, except we can specify an exit status.
682 */
683void
684die(status)
685    int status;
686{
687    cleanup();
688    syslog(LOG_INFO, "Exit.");
689    exit(status);
690}
691
692/*
693 * connect_time_expired - log a message and close the connection.
694 */
695static void
696connect_time_expired(arg)
697    caddr_t arg;
698{
699    syslog(LOG_INFO, "Connect time expired");
700    lcp_close(0, "Connect time expired");	/* Close connection */
701}
702
703/*
704 * cleanup - restore anything which needs to be restored before we exit
705 */
706/* ARGSUSED */
707static void
708cleanup()
709{
710    sys_cleanup();
711
712    if (ttyfd >= 0)
713	close_tty();
714
715    if (pidfilename[0] != 0 && unlink(pidfilename) < 0 && errno != ENOENT)
716	syslog(LOG_WARNING, "unable to delete pid file: %m");
717    pidfilename[0] = 0;
718
719    if (locked)
720	unlock();
721}
722
723/*
724 * close_tty - restore the terminal device and close it.
725 */
726static void
727close_tty()
728{
729    disestablish_ppp(ttyfd);
730
731    /* drop dtr to hang up */
732    if (modem) {
733	setdtr(ttyfd, FALSE);
734	/*
735	 * This sleep is in case the serial port has CLOCAL set by default,
736	 * and consequently will reassert DTR when we close the device.
737	 */
738	sleep(1);
739    }
740
741    restore_tty(ttyfd);
742
743    if (tty_mode != (mode_t) -1)
744      chmod(devnam, tty_mode);
745
746    close(ttyfd);
747    ttyfd = -1;
748}
749
750
751struct	callout {
752    struct timeval	c_time;		/* time at which to call routine */
753    caddr_t		c_arg;		/* argument to routine */
754    void		(*c_func)();	/* routine */
755    struct		callout *c_next;
756};
757
758static struct callout *callout = NULL;	/* Callout list */
759static struct timeval timenow;		/* Current time */
760
761/*
762 * timeout - Schedule a timeout.
763 *
764 * Note that this timeout takes the number of seconds, NOT hz (as in
765 * the kernel).
766 */
767void
768timeout(func, arg, time)
769    void (*func)();
770    caddr_t arg;
771    int time;
772{
773    struct callout *newp, *p, **pp;
774
775    MAINDEBUG((LOG_DEBUG, "Timeout %lx:%lx in %d seconds.",
776	       (long) func, (long) arg, time));
777
778    /*
779     * Allocate timeout.
780     */
781    if ((newp = (struct callout *) malloc(sizeof(struct callout))) == NULL) {
782	syslog(LOG_ERR, "Out of memory in timeout()!");
783	die(1);
784    }
785    newp->c_arg = arg;
786    newp->c_func = func;
787    gettimeofday(&timenow, NULL);
788    newp->c_time.tv_sec = timenow.tv_sec + time;
789    newp->c_time.tv_usec = timenow.tv_usec;
790
791    /*
792     * Find correct place and link it in.
793     */
794    for (pp = &callout; (p = *pp); pp = &p->c_next)
795	if (newp->c_time.tv_sec < p->c_time.tv_sec
796	    || (newp->c_time.tv_sec == p->c_time.tv_sec
797		&& newp->c_time.tv_usec < p->c_time.tv_sec))
798	    break;
799    newp->c_next = p;
800    *pp = newp;
801}
802
803
804/*
805 * untimeout - Unschedule a timeout.
806 */
807void
808untimeout(func, arg)
809    void (*func)();
810    caddr_t arg;
811{
812    struct callout **copp, *freep;
813
814    MAINDEBUG((LOG_DEBUG, "Untimeout %lx:%lx.", (long) func, (long) arg));
815
816    /*
817     * Find first matching timeout and remove it from the list.
818     */
819    for (copp = &callout; (freep = *copp); copp = &freep->c_next)
820	if (freep->c_func == func && freep->c_arg == arg) {
821	    *copp = freep->c_next;
822	    (void) free((char *) freep);
823	    break;
824	}
825}
826
827
828/*
829 * calltimeout - Call any timeout routines which are now due.
830 */
831static void
832calltimeout()
833{
834    struct callout *p;
835
836    while (callout != NULL) {
837	p = callout;
838
839	if (gettimeofday(&timenow, NULL) < 0) {
840	    syslog(LOG_ERR, "Failed to get time of day: %m");
841	    die(1);
842	}
843	if (!(p->c_time.tv_sec < timenow.tv_sec
844	      || (p->c_time.tv_sec == timenow.tv_sec
845		  && p->c_time.tv_usec <= timenow.tv_usec)))
846	    break;		/* no, it's not time yet */
847
848	callout = p->c_next;
849	(*p->c_func)(p->c_arg);
850
851	free((char *) p);
852    }
853}
854
855
856/*
857 * timeleft - return the length of time until the next timeout is due.
858 */
859static struct timeval *
860timeleft(tvp)
861    struct timeval *tvp;
862{
863    if (callout == NULL)
864	return NULL;
865
866    gettimeofday(&timenow, NULL);
867    tvp->tv_sec = callout->c_time.tv_sec - timenow.tv_sec;
868    tvp->tv_usec = callout->c_time.tv_usec - timenow.tv_usec;
869    if (tvp->tv_usec < 0) {
870	tvp->tv_usec += 1000000;
871	tvp->tv_sec -= 1;
872    }
873    if (tvp->tv_sec < 0)
874	tvp->tv_sec = tvp->tv_usec = 0;
875
876    return tvp;
877}
878
879
880/*
881 * kill_my_pg - send a signal to our process group, and ignore it ourselves.
882 */
883static void
884kill_my_pg(sig)
885    int sig;
886{
887    struct sigaction act, oldact;
888
889    act.sa_handler = SIG_IGN;
890    act.sa_flags = 0;
891    sigaction(sig, &act, &oldact);
892    kill(-getpgrp(), sig);
893    sigaction(sig, &oldact, NULL);
894}
895
896
897/*
898 * hup - Catch SIGHUP signal.
899 *
900 * Indicates that the physical layer has been disconnected.
901 * We don't rely on this indication; if the user has sent this
902 * signal, we just take the link down.
903 */
904static void
905hup(sig)
906    int sig;
907{
908    syslog(LOG_INFO, "Hangup (SIGHUP)");
909    kill_link = 1;
910    if (conn_running)
911	/* Send the signal to the [dis]connector process(es) also */
912	kill_my_pg(sig);
913}
914
915
916/*
917 * term - Catch SIGTERM signal and SIGINT signal (^C/del).
918 *
919 * Indicates that we should initiate a graceful disconnect and exit.
920 */
921/*ARGSUSED*/
922static void
923term(sig)
924    int sig;
925{
926    syslog(LOG_INFO, "Terminating on signal %d.", sig);
927    persist = 0;		/* don't try to restart */
928    kill_link = 1;
929    if (conn_running)
930	/* Send the signal to the [dis]connector process(es) also */
931	kill_my_pg(sig);
932}
933
934
935/*
936 * chld - Catch SIGCHLD signal.
937 * Calls reap_kids to get status for any dead kids.
938 */
939static void
940chld(sig)
941    int sig;
942{
943    reap_kids();
944}
945
946
947/*
948 * toggle_debug - Catch SIGUSR1 signal.
949 *
950 * Toggle debug flag.
951 */
952/*ARGSUSED*/
953static void
954toggle_debug(sig)
955    int sig;
956{
957    debug = !debug;
958    if (debug) {
959      setlogmask(LOG_UPTO(LOG_DEBUG));
960    } else {
961      setlogmask(LOG_UPTO(LOG_WARNING));
962    }
963}
964
965
966/*
967 * open_ccp - Catch SIGUSR2 signal.
968 *
969 * Try to (re)negotiate compression.
970 */
971/*ARGSUSED*/
972static void
973open_ccp(sig)
974    int sig;
975{
976    open_ccp_flag = 1;
977}
978
979
980/*
981 * bad_signal - We've caught a fatal signal.  Clean up state and exit.
982 */
983static void
984bad_signal(sig)
985    int sig;
986{
987    syslog(LOG_ERR, "Fatal signal %d", sig);
988    if (conn_running)
989	kill_my_pg(SIGTERM);
990    die(1);
991}
992
993
994/*
995 * device_script - run a program to connect or disconnect the
996 * serial device.
997 */
998static int
999device_script(program, in, out)
1000    char *program;
1001    int in, out;
1002{
1003    int pid;
1004    int status;
1005    int errfd;
1006
1007    conn_running = 1;
1008    pid = fork();
1009
1010    if (pid < 0) {
1011	conn_running = 0;
1012	syslog(LOG_ERR, "Failed to create child process: %m");
1013	die(1);
1014    }
1015
1016    if (pid == 0) {
1017	sys_close();
1018        closelog();
1019        if (in == out) {
1020            if (in != 0) {
1021                dup2(in, 0);
1022                close(in);
1023            }
1024            dup2(0, 1);
1025        } else {
1026            if (out == 0)
1027                out = dup(out);
1028            if (in != 0) {
1029                dup2(in, 0);
1030                close(in);
1031            }
1032            if (out != 1) {
1033	        dup2(out, 1);
1034                close(out);
1035            }
1036        }
1037        if (redirect_stderr) {
1038            close(2);
1039            errfd = open(_PATH_CONNERRS, O_WRONLY | O_APPEND | O_CREAT, 0644);
1040            if (errfd >= 0 && errfd != 2) {
1041	        dup2(errfd, 2);
1042                close(errfd);
1043            }
1044        }
1045	/* revoke privs */
1046	seteuid(getuid());
1047	setuid(getuid());
1048	setegid(getgid());
1049	setgid(getgid());
1050	execl("/bin/sh", "sh", "-c", program, (char *)0);
1051	syslog(LOG_ERR, "could not exec /bin/sh: %m");
1052	_exit(99);
1053	/* NOTREACHED */
1054    }
1055
1056    while (waitpid(pid, &status, 0) < 0) {
1057	if (errno == EINTR)
1058	    continue;
1059	syslog(LOG_ERR, "error waiting for (dis)connection process: %m");
1060	die(1);
1061    }
1062    conn_running = 0;
1063
1064    return (status == 0 ? 0 : -1);
1065}
1066
1067
1068/*
1069 * run-program - execute a program with given arguments,
1070 * but don't wait for it.
1071 * If the program can't be executed, logs an error unless
1072 * must_exist is 0 and the program file doesn't exist.
1073 */
1074int
1075run_program(prog, args, must_exist)
1076    char *prog;
1077    char **args;
1078    int must_exist;
1079{
1080    int pid;
1081    char *nullenv[1];
1082
1083    pid = fork();
1084    if (pid == -1) {
1085	syslog(LOG_ERR, "Failed to create child process for %s: %m", prog);
1086	return -1;
1087    }
1088    if (pid == 0) {
1089	int new_fd;
1090
1091	/* Leave the current location */
1092	(void) setsid();    /* No controlling tty. */
1093	(void) umask (S_IRWXG|S_IRWXO);
1094	(void) chdir ("/"); /* no current directory. */
1095	setuid(geteuid());
1096	setgid(getegid());
1097
1098	/* Ensure that nothing of our device environment is inherited. */
1099	sys_close();
1100        closelog();
1101	close (0);
1102	close (1);
1103	close (2);
1104	close (ttyfd);  /* tty interface to the ppp device */
1105
1106        /* Don't pass handles to the PPP device, even by accident. */
1107	new_fd = open (_PATH_DEVNULL, O_RDWR);
1108	if (new_fd >= 0) {
1109	    if (new_fd != 0) {
1110	        dup2  (new_fd, 0); /* stdin <- /dev/null */
1111		close (new_fd);
1112	    }
1113	    dup2 (0, 1); /* stdout -> /dev/null */
1114	    dup2 (0, 2); /* stderr -> /dev/null */
1115	}
1116
1117#ifdef BSD
1118	/* Force the priority back to zero if pppd is running higher. */
1119	if (setpriority (PRIO_PROCESS, 0, 0) < 0)
1120	    syslog (LOG_WARNING, "can't reset priority to 0: %m");
1121#endif
1122
1123	/* SysV recommends a second fork at this point. */
1124
1125        /* run the program; give it a null environment */
1126	nullenv[0] = NULL;
1127	execve(prog, args, nullenv);
1128	if (must_exist || errno != ENOENT)
1129	    syslog(LOG_WARNING, "Can't execute %s: %m", prog);
1130	_exit(-1);
1131    }
1132    MAINDEBUG((LOG_DEBUG, "Script %s started; pid = %d", prog, pid));
1133    ++n_children;
1134    return 0;
1135}
1136
1137
1138/*
1139 * reap_kids - get status from any dead child processes,
1140 * and log a message for abnormal terminations.
1141 */
1142static void
1143reap_kids()
1144{
1145    int pid, status;
1146
1147    if (n_children == 0)
1148	return;
1149    if ((pid = waitpid(-1, &status, WNOHANG)) == -1) {
1150	if (errno != ECHILD)
1151	    syslog(LOG_ERR, "Error waiting for child process: %m");
1152	return;
1153    }
1154    if (pid > 0) {
1155	--n_children;
1156	if (WIFSIGNALED(status)) {
1157	    syslog(LOG_WARNING, "Child process %d terminated with signal %d",
1158		   pid, WTERMSIG(status));
1159	}
1160    }
1161}
1162
1163
1164/*
1165 * log_packet - format a packet and log it.
1166 */
1167
1168char line[256];			/* line to be logged accumulated here */
1169char *linep;
1170
1171void
1172log_packet(p, len, prefix)
1173    u_char *p;
1174    int len;
1175    char *prefix;
1176{
1177    strcpy(line, prefix);
1178    linep = line + strlen(line);
1179    format_packet(p, len, pr_log, NULL);
1180    if (linep != line)
1181	syslog(LOG_DEBUG, "%s", line);
1182}
1183
1184/*
1185 * format_packet - make a readable representation of a packet,
1186 * calling `printer(arg, format, ...)' to output it.
1187 */
1188void
1189format_packet(p, len, printer, arg)
1190    u_char *p;
1191    int len;
1192    void (*printer) __P((void *, char *, ...));
1193    void *arg;
1194{
1195    int i, n;
1196    u_short proto;
1197    u_char x;
1198    struct protent *protp;
1199
1200    if (len >= PPP_HDRLEN && p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) {
1201	p += 2;
1202	GETSHORT(proto, p);
1203	len -= PPP_HDRLEN;
1204	for (i = 0; (protp = protocols[i]) != NULL; ++i)
1205	    if (proto == protp->protocol)
1206		break;
1207	if (protp != NULL) {
1208	    printer(arg, "[%s", protp->name);
1209	    n = (*protp->printpkt)(p, len, printer, arg);
1210	    printer(arg, "]");
1211	    p += n;
1212	    len -= n;
1213	} else {
1214	    printer(arg, "[proto=0x%x]", proto);
1215	}
1216    }
1217
1218    for (; len > 0; --len) {
1219	GETCHAR(x, p);
1220	printer(arg, " %.2x", x);
1221    }
1222}
1223
1224static void
1225pr_log __V((void *arg, char *fmt, ...))
1226{
1227    int n;
1228    va_list pvar;
1229    char buf[256];
1230
1231#ifdef __STDC__
1232    va_start(pvar, fmt);
1233#else
1234    void *arg;
1235    char *fmt;
1236    va_start(pvar);
1237    arg = va_arg(pvar, void *);
1238    fmt = va_arg(pvar, char *);
1239#endif
1240
1241    vsprintf(buf, fmt, pvar);
1242    va_end(pvar);
1243
1244    n = strlen(buf);
1245    if (linep + n + 1 > line + sizeof(line)) {
1246	syslog(LOG_DEBUG, "%s", line);
1247	linep = line;
1248    }
1249    strcpy(linep, buf);
1250    linep += n;
1251}
1252
1253/*
1254 * print_string - print a readable representation of a string using
1255 * printer.
1256 */
1257void
1258print_string(p, len, printer, arg)
1259    char *p;
1260    int len;
1261    void (*printer) __P((void *, char *, ...));
1262    void *arg;
1263{
1264    int c;
1265
1266    printer(arg, "\"");
1267    for (; len > 0; --len) {
1268	c = *p++;
1269        if (' ' <= c && c <= '~') {
1270            if (c == '\\' || c == '"')
1271                printer(arg, "\\");
1272	    printer(arg, "%c", c);
1273        } else {
1274            switch (c) {
1275            case '\n':
1276                printer(arg, "\\n");
1277                break;
1278            case '\r':
1279                printer(arg, "\\r");
1280                break;
1281            case '\t':
1282                printer(arg, "\\t");
1283                break;
1284            default:
1285	        printer(arg, "\\%.3o", c);
1286            }
1287      }
1288    }
1289
1290    printer(arg, "\"");
1291}
1292
1293/*
1294 * novm - log an error message saying we ran out of memory, and die.
1295 */
1296void
1297novm(msg)
1298    char *msg;
1299{
1300    syslog(LOG_ERR, "Virtual memory exhausted allocating %s\n", msg);
1301    die(1);
1302}
1303
1304/*
1305 * fmtmsg - format a message into a buffer.  Like sprintf except we
1306 * also specify the length of the output buffer, and we handle
1307 * %r (recursive format), %m (error message) and %I (IP address) formats.
1308 * Doesn't do floating-point formats.
1309 * Returns the number of chars put into buf.
1310 */
1311int
1312fmtmsg __V((char *buf, int buflen, char *fmt, ...))
1313{
1314    va_list args;
1315    int n;
1316
1317#ifdef __STDC__
1318    va_start(args, fmt);
1319#else
1320    char *buf;
1321    int buflen;
1322    char *fmt;
1323    va_start(args);
1324    buf = va_arg(args, char *);
1325    buflen = va_arg(args, int);
1326    fmt = va_arg(args, char *);
1327#endif
1328    n = vfmtmsg(buf, buflen, fmt, args);
1329    va_end(args);
1330    return n;
1331}
1332
1333/*
1334 * vfmtmsg - like fmtmsg, takes a va_list instead of a list of args.
1335 */
1336#define OUTCHAR(c)      (buflen > 0? (--buflen, *buf++ = (c)): 0)
1337
1338int
1339vfmtmsg(buf, buflen, fmt, args)
1340    char *buf;
1341    int buflen;
1342    char *fmt;
1343    va_list args;
1344{
1345    int c, i, n;
1346    int width, prec, fillch;
1347    int base, len, neg, quoted;
1348    unsigned long val;
1349    char *str, *f, *buf0;
1350    unsigned char *p;
1351    va_list a;
1352    char num[32];
1353    time_t t;
1354    static char hexchars[] = "0123456789abcdef";
1355
1356    buf0 = buf;
1357    --buflen;
1358    while (buflen > 0) {
1359        for (f = fmt; *f != '%' && *f != 0; ++f)
1360            ;
1361        if (f > fmt) {
1362            len = f - fmt;
1363            if (len > buflen)
1364                len = buflen;
1365            memcpy(buf, fmt, len);
1366            buf += len;
1367            buflen -= len;
1368            fmt = f;
1369        }
1370        if (*fmt == 0)
1371            break;
1372        c = *++fmt;
1373        width = prec = 0;
1374        fillch = ' ';
1375        if (c == '0') {
1376            fillch = '0';
1377            c = *++fmt;
1378        }
1379        if (c == '*') {
1380            width = va_arg(args, int);
1381            c = *++fmt;
1382        } else {
1383            while (isdigit(c)) {
1384                width = width * 10 + c - '0';
1385                c = *++fmt;
1386            }
1387        }
1388        if (c == '.') {
1389            c = *++fmt;
1390            if (c == '*') {
1391                prec = va_arg(args, int);
1392                c = *++fmt;
1393            } else {
1394                while (isdigit(c)) {
1395                    prec = prec * 10 + c - '0';
1396                    c = *++fmt;
1397                }
1398            }
1399        }
1400        str = 0;
1401        base = 0;
1402        neg = 0;
1403        ++fmt;
1404        switch (c) {
1405        case 'd':
1406            i = va_arg(args, int);
1407            if (i < 0) {
1408                neg = 1;
1409                val = -i;
1410            } else
1411                val = i;
1412            base = 10;
1413            break;
1414        case 'o':
1415            val = va_arg(args, unsigned int);
1416            base = 8;
1417            break;
1418        case 'x':
1419            val = va_arg(args, unsigned int);
1420            base = 16;
1421            break;
1422        case 'p':
1423            val = (unsigned long) va_arg(args, void *);
1424            base = 16;
1425            neg = 2;
1426            break;
1427        case 's':
1428            str = va_arg(args, char *);
1429            break;
1430        case 'c':
1431            num[0] = va_arg(args, int);
1432            num[1] = 0;
1433            str = num;
1434            break;
1435        case 'm':
1436            str = strerror(errno);
1437            break;
1438        case 'I':
1439            str = ip_ntoa(va_arg(args, u_int32_t));
1440            break;
1441        case 'r':
1442            f = va_arg(args, char *);
1443	    /*
1444	     * XXX We assume a va_list is either a pointer or an array, so
1445	     * what gets passed for a va_list is like a void * in some sense.
1446	     */
1447	    a = va_arg(args, va_list);
1448            n = vfmtmsg(buf, buflen + 1, f, a);
1449            buf += n;
1450            buflen -= n;
1451            continue;
1452        case 't':
1453            time(&t);
1454            str = ctime(&t);
1455            str += 4;           /* chop off the day name */
1456            str[15] = 0;        /* chop off year and newline */
1457            break;
1458        case 'v':               /* "visible" string */
1459        case 'q':               /* quoted string */
1460            quoted = c == 'q';
1461            p = va_arg(args, unsigned char *);
1462            if (fillch == '0' && prec > 0) {
1463                n = prec;
1464            } else {
1465                n = strlen((char *)p);
1466                if (prec > 0 && prec < n)
1467                    n = prec;
1468            }
1469            while (n > 0 && buflen > 0) {
1470                c = *p++;
1471                --n;
1472                if (!quoted && c >= 0x80) {
1473                    OUTCHAR('M');
1474                    OUTCHAR('-');
1475                    c -= 0x80;
1476                }
1477                if (quoted && (c == '"' || c == '\\'))
1478                    OUTCHAR('\\');
1479                if (c < 0x20 || 0x7f <= c && c < 0xa0) {
1480                    if (quoted) {
1481                        OUTCHAR('\\');
1482                        switch (c) {
1483                        case '\t':      OUTCHAR('t');   break;
1484                        case '\n':      OUTCHAR('n');   break;
1485                        case '\b':      OUTCHAR('b');   break;
1486                        case '\f':      OUTCHAR('f');   break;
1487                        default:
1488                            OUTCHAR('x');
1489                            OUTCHAR(hexchars[c >> 4]);
1490                            OUTCHAR(hexchars[c & 0xf]);
1491                        }
1492                    } else {
1493                        if (c == '\t')
1494                            OUTCHAR(c);
1495                        else {
1496                            OUTCHAR('^');
1497                            OUTCHAR(c ^ 0x40);
1498                        }
1499                    }
1500                } else
1501                    OUTCHAR(c);
1502            }
1503            continue;
1504        default:
1505            *buf++ = '%';
1506            if (c != '%')
1507                --fmt;          /* so %z outputs %z etc. */
1508            --buflen;
1509            continue;
1510        }
1511        if (base != 0) {
1512            str = num + sizeof(num);
1513            *--str = 0;
1514            while (str > num + neg) {
1515                *--str = hexchars[val % base];
1516                val = val / base;
1517                if (--prec <= 0 && val == 0)
1518                    break;
1519            }
1520            switch (neg) {
1521            case 1:
1522                *--str = '-';
1523                break;
1524            case 2:
1525                *--str = 'x';
1526                *--str = '0';
1527                break;
1528            }
1529            len = num + sizeof(num) - 1 - str;
1530        } else {
1531            len = strlen(str);
1532            if (prec > 0 && len > prec)
1533                len = prec;
1534        }
1535        if (width > 0) {
1536            if (width > buflen)
1537                width = buflen;
1538            if ((n = width - len) > 0) {
1539                buflen -= n;
1540                for (; n > 0; --n)
1541                    *buf++ = fillch;
1542            }
1543        }
1544        if (len > buflen)
1545            len = buflen;
1546        memcpy(buf, str, len);
1547        buf += len;
1548        buflen -= len;
1549    }
1550    *buf = 0;
1551    return buf - buf0;
1552}
1553