xref: /openbsd/usr.sbin/pppd/main.c (revision 404b540a)
1 /*	$OpenBSD: main.c,v 1.47 2007/09/02 15:19:39 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 #ifndef lint
46 #if 0
47 static char rcsid[] = "Id: main.c,v 1.49 1998/05/05 05:24:17 paulus Exp $";
48 #else
49 static char rcsid[] = "$OpenBSD: main.c,v 1.47 2007/09/02 15:19:39 deraadt Exp $";
50 #endif
51 #endif
52 
53 #include <stdio.h>
54 #include <ctype.h>
55 #include <stdlib.h>
56 #include <string.h>
57 #include <unistd.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 #include <sys/param.h>
66 #include <sys/types.h>
67 #include <sys/wait.h>
68 #include <sys/time.h>
69 #include <sys/resource.h>
70 #include <sys/stat.h>
71 #include <sys/socket.h>
72 #include <net/if.h>
73 
74 #include "pppd.h"
75 #include "magic.h"
76 #include "fsm.h"
77 #include "lcp.h"
78 #include "ipcp.h"
79 #include "upap.h"
80 #include "chap.h"
81 #include "ccp.h"
82 #include "pathnames.h"
83 #include "patchlevel.h"
84 
85 #ifdef CBCP_SUPPORT
86 #include "cbcp.h"
87 #endif
88 
89 #if defined(SUNOS4)
90 extern char *strerror();
91 #endif
92 
93 #ifdef AT_CHANGE
94 #include "atcp.h"
95 #endif
96 
97 /* interface vars */
98 char ifname[IFNAMSIZ];		/* Interface name */
99 int ifunit;			/* Interface unit number */
100 
101 char *progname;			/* Name of this program */
102 char hostname[MAXHOSTNAMELEN];	/* Our hostname */
103 static char pidfilename[MAXPATHLEN];	/* name of pid file */
104 static char default_devnam[MAXPATHLEN];	/* name of default device */
105 static pid_t pid;		/* Our pid */
106 static uid_t uid;		/* Our real user-id */
107 static int conn_running;	/* we have a [dis]connector running */
108 static int crashed = 0;
109 
110 int ttyfd = -1;			/* Serial port file descriptor */
111 mode_t tty_mode = -1;		/* Original access permissions to tty */
112 int baud_rate;			/* Actual bits/second for serial device */
113 int hungup;			/* terminal has been hung up */
114 int privileged;			/* we're running as real uid root */
115 int need_holdoff;		/* need holdoff period before restarting */
116 int detached;			/* have detached from terminal */
117 
118 int phase;			/* where the link is at */
119 int kill_link;
120 int open_ccp_flag;
121 
122 char **script_env;		/* Env. variable values for scripts */
123 int s_env_nalloc;		/* # words avail at script_env */
124 
125 u_char outpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for outgoing packet */
126 u_char inpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for incoming packet */
127 
128 static int n_children;		/* # child processes still running */
129 
130 static int locked;		/* lock() has succeeded */
131 
132 char *no_ppp_msg = "Sorry - this system lacks PPP kernel support\n";
133 
134 /* Prototypes for procedures local to this file. */
135 
136 static void create_pidfile(void);
137 static void cleanup(void);
138 static void close_tty(void);
139 static void get_input(void);
140 static void calltimeout(void);
141 static struct timeval *timeleft(struct timeval *);
142 static void kill_my_pg(int);
143 static void hup(int);
144 static void term(int);
145 static void chld(int);
146 static void toggle_debug(int);
147 static void open_ccp(int);
148 static void bad_signal(int);
149 static void holdoff_end(void *);
150 static int device_script(char *, int, int);
151 static void reap_kids(void);
152 static void pr_log(void *, char *, ...);
153 
154 extern	char	*ttyname(int);
155 extern	char	*getlogin(void);
156 int main(int, char *[]);
157 
158 #ifdef ultrix
159 #undef	O_NONBLOCK
160 #define	O_NONBLOCK	O_NDELAY
161 #endif
162 
163 #ifdef ULTRIX
164 #define setlogmask(x)
165 #endif
166 
167 /*
168  * PPP Data Link Layer "protocol" table.
169  * One entry per supported protocol.
170  * The last entry must be NULL.
171  */
172 struct protent *protocols[] = {
173     &lcp_protent,
174     &pap_protent,
175     &chap_protent,
176 #ifdef CBCP_SUPPORT
177     &cbcp_protent,
178 #endif
179     &ipcp_protent,
180     &ccp_protent,
181 #ifdef AT_CHANGE
182     &atcp_protent,
183 #endif
184     NULL
185 };
186 
187 int
188 main(argc, argv)
189     int argc;
190     char *argv[];
191 {
192     int i, fdflags;
193     struct sigaction sa;
194     char *p;
195     struct passwd *pw;
196     struct timeval timo;
197     sigset_t mask;
198     struct protent *protp;
199     struct stat statbuf;
200     char numbuf[16];
201 
202     phase = PHASE_INITIALIZE;
203     p = ttyname(0);
204     if (p)
205 	strlcpy(devnam, p, MAXPATHLEN);
206     strlcpy(default_devnam, devnam, sizeof default_devnam);
207 
208     script_env = NULL;
209 
210     /* Initialize syslog facilities */
211 #ifdef ULTRIX
212     openlog("pppd", LOG_PID);
213 #else
214     openlog("pppd", LOG_PID | LOG_NDELAY, LOG_PPP);
215     setlogmask(LOG_UPTO(LOG_INFO));
216 #endif
217 
218     if (gethostname(hostname, sizeof hostname) < 0 ) {
219 	option_error("Couldn't get hostname: %m");
220 	die(1);
221     }
222 
223     uid = getuid();
224     privileged = uid == 0;
225     snprintf(numbuf, sizeof numbuf, "%u", uid);
226     script_setenv("UID", numbuf);
227 
228     /*
229      * Initialize to the standard option set, then parse, in order,
230      * the system options file, the user's options file,
231      * the tty's options file, and the command line arguments.
232      */
233     for (i = 0; (protp = protocols[i]) != NULL; ++i)
234 	(*protp->init)(0);
235 
236     progname = *argv;
237 
238     if (!options_from_file(_PATH_SYSOPTIONS, !privileged, 0, 1)
239 	|| !options_from_user())
240 	exit(1);
241     scan_args(argc-1, argv+1);	/* look for tty name on command line */
242     if (!options_for_tty()
243 	|| !parse_args(argc-1, argv+1))
244 	exit(1);
245 
246     /*
247      * Check that we are running as root.
248      */
249     if (geteuid() != 0) {
250 	option_error("must be root to run %s, since it is not setuid-root",
251 		     argv[0]);
252 	die(1);
253     }
254 
255     if (!ppp_available()) {
256 	option_error(no_ppp_msg);
257 	exit(1);
258     }
259 
260     /*
261      * Check that the options given are valid and consistent.
262      */
263     sys_check_options();
264     auth_check_options();
265     for (i = 0; (protp = protocols[i]) != NULL; ++i)
266 	if (protp->check_options != NULL)
267 	    (*protp->check_options)();
268     if (demand && connector == 0) {
269 	option_error("connect script required for demand-dialling\n");
270 	exit(1);
271     }
272 
273     script_setenv("DEVICE", devnam);
274     snprintf(numbuf, sizeof numbuf, "%d", baud_rate);
275     script_setenv("SPEED", numbuf);
276 
277     /*
278      * If the user has specified the default device name explicitly,
279      * pretend they hadn't.
280      */
281     if (!default_device && strcmp(devnam, default_devnam) == 0)
282 	default_device = 1;
283     if (default_device)
284 	nodetach = 1;
285 
286     /*
287      * Initialize system-dependent stuff and magic number package.
288      */
289     sys_init();
290     magic_init();
291     if (debug)
292 	setlogmask(LOG_UPTO(LOG_DEBUG));
293 
294     /*
295      * Detach ourselves from the terminal, if required,
296      * and identify who is running us.
297      */
298     if (nodetach == 0)
299 	detach();
300     pid = getpid();
301     p = getlogin();
302     if (p == NULL) {
303 	pw = getpwuid(uid);
304 	if (pw != NULL && pw->pw_name != NULL)
305 	    p = pw->pw_name;
306 	else
307 	    p = "(unknown)";
308     }
309     syslog(LOG_NOTICE, "pppd %s.%d%s started by %s, uid %u",
310 	   VERSION, PATCHLEVEL, IMPLEMENTATION, p, uid);
311 
312     /*
313      * Compute mask of all interesting signals and install signal handlers
314      * for each.  Only one signal handler may be active at a time.  Therefore,
315      * all other signals should be masked when any handler is executing.
316      */
317     sigemptyset(&mask);
318     sigaddset(&mask, SIGHUP);
319     sigaddset(&mask, SIGINT);
320     sigaddset(&mask, SIGTERM);
321     sigaddset(&mask, SIGCHLD);
322 
323 #define SIGNAL(s, handler)	{ \
324 	sa.sa_handler = handler; \
325 	if (sigaction(s, &sa, NULL) < 0) { \
326 	    syslog(LOG_ERR, "Couldn't establish signal handler (%d): %m", s); \
327 	    die(1); \
328 	} \
329     }
330 
331     sa.sa_mask = mask;
332     sa.sa_flags = 0;
333     SIGNAL(SIGHUP, hup);		/* Hangup */
334     SIGNAL(SIGINT, term);		/* Interrupt */
335     SIGNAL(SIGTERM, term);		/* Terminate */
336     SIGNAL(SIGCHLD, chld);
337 
338     SIGNAL(SIGUSR1, toggle_debug);	/* Toggle debug flag */
339     SIGNAL(SIGUSR2, open_ccp);		/* Reopen CCP */
340 
341     /*
342      * Install a handler for other signals which would otherwise
343      * cause pppd to exit without cleaning up.
344      */
345     SIGNAL(SIGABRT, bad_signal);
346     SIGNAL(SIGALRM, bad_signal);
347     SIGNAL(SIGFPE, bad_signal);
348     SIGNAL(SIGILL, bad_signal);
349     SIGNAL(SIGPIPE, bad_signal);
350     SIGNAL(SIGQUIT, bad_signal);
351 #if SIGSEGV_CHECK
352     SIGNAL(SIGSEGV, bad_signal);
353 #endif
354 #ifdef SIGBUS
355     SIGNAL(SIGBUS, bad_signal);
356 #endif
357 #ifdef SIGEMT
358     SIGNAL(SIGEMT, bad_signal);
359 #endif
360 #ifdef SIGPOLL
361     SIGNAL(SIGPOLL, bad_signal);
362 #endif
363 #ifdef SIGPROF
364     SIGNAL(SIGPROF, bad_signal);
365 #endif
366 #ifdef SIGSYS
367     SIGNAL(SIGSYS, bad_signal);
368 #endif
369 #ifdef SIGTRAP
370     SIGNAL(SIGTRAP, bad_signal);
371 #endif
372 #ifdef SIGVTALRM
373     SIGNAL(SIGVTALRM, bad_signal);
374 #endif
375 #ifdef SIGXCPU
376     SIGNAL(SIGXCPU, bad_signal);
377 #endif
378 #ifdef SIGXFSZ
379     SIGNAL(SIGXFSZ, bad_signal);
380 #endif
381 
382     /*
383      * Apparently we can get a SIGPIPE when we call syslog, if
384      * syslogd has died and been restarted.  Ignoring it seems
385      * be sufficient.
386      */
387     signal(SIGPIPE, SIG_IGN);
388 
389     /*
390      * If we're doing dial-on-demand, set up the interface now.
391      */
392     if (demand) {
393 	/*
394 	 * Open the loopback channel and set it up to be the ppp interface.
395 	 */
396 	open_ppp_loopback();
397 
398 	syslog(LOG_INFO, "Using interface ppp%d", ifunit);
399 	(void) snprintf(ifname, sizeof ifname, "ppp%d", ifunit);
400 	script_setenv("IFNAME", ifname);
401 
402 	create_pidfile();	/* write pid to file */
403 
404 	/*
405 	 * Configure the interface and mark it up, etc.
406 	 */
407 	demand_conf();
408     }
409 
410     for (;;) {
411 
412 	need_holdoff = 1;
413 
414 	if (demand) {
415 	    /*
416 	     * Don't do anything until we see some activity.
417 	     */
418 	    phase = PHASE_DORMANT;
419 	    kill_link = 0;
420 	    demand_unblock();
421 	    for (;;) {
422 		wait_loop_output(timeleft(&timo));
423 		calltimeout();
424 		if (kill_link) {
425 		    if (!persist)
426 			die(0);
427 		    kill_link = 0;
428 		}
429 		if (get_loop_output())
430 		    break;
431 		reap_kids();
432 	    }
433 
434 	    /*
435 	     * Now we want to bring up the link.
436 	     */
437 	    demand_drop();
438 	    syslog(LOG_INFO, "Starting link");
439 	}
440 
441 	/*
442 	 * Lock the device if we've been asked to.
443 	 */
444 	if (lockflag && !default_device) {
445 	    if (lock(devnam) < 0)
446 		goto fail;
447 	    locked = 1;
448 	}
449 
450 	/*
451 	 * Open the serial device and set it up to be the ppp interface.
452 	 * First we open it in non-blocking mode so we can set the
453 	 * various termios flags appropriately.  If we aren't dialling
454 	 * out and we want to use the modem lines, we reopen it later
455 	 * in order to wait for the carrier detect signal from the modem.
456 	 */
457 	while ((ttyfd = open(devnam, O_NONBLOCK | O_RDWR, 0)) < 0) {
458 	    if (errno != EINTR)
459 		syslog(LOG_ERR, "Failed to open %s: %m", devnam);
460 	    if (!persist || errno != EINTR)
461 		goto fail;
462 	}
463 	if ((fdflags = fcntl(ttyfd, F_GETFL)) == -1
464 	    || fcntl(ttyfd, F_SETFL, fdflags & ~O_NONBLOCK) < 0)
465 	    syslog(LOG_WARNING,
466 		   "Couldn't reset non-blocking mode on device: %m");
467 
468 	hungup = 0;
469 	kill_link = 0;
470 
471 	/*
472 	 * Do the equivalent of `mesg n' to stop broadcast messages.
473 	 */
474 	if (fstat(ttyfd, &statbuf) < 0
475 	    || fchmod(ttyfd, statbuf.st_mode & ~(S_IWGRP | S_IWOTH)) < 0) {
476 	    syslog(LOG_WARNING,
477 		   "Couldn't restrict write permissions to %s: %m", devnam);
478 	} else
479 	    tty_mode = statbuf.st_mode;
480 
481 	/* run connection script */
482 	if (connector && connector[0]) {
483 	    MAINDEBUG((LOG_INFO, "Connecting with <%s>", connector));
484 
485 	    /*
486 	     * Set line speed, flow control, etc.
487 	     * On most systems we set CLOCAL for now so that we can talk
488 	     * to the modem before carrier comes up.  But this has the
489 	     * side effect that we might miss it if CD drops before we
490 	     * get to clear CLOCAL below.  On systems where we can talk
491 	     * successfully to the modem with CLOCAL clear and CD down,
492 	     * we can clear CLOCAL at this point.
493 	     */
494 	    set_up_tty(ttyfd, (modem_chat == 0));
495 
496 	    /* drop dtr to hang up in case modem is off hook */
497 	    if (!default_device && modem) {
498 		setdtr(ttyfd, FALSE);
499 		sleep(1);
500 		setdtr(ttyfd, TRUE);
501 	    }
502 
503 	    if (device_script(connector, ttyfd, ttyfd) < 0) {
504 		syslog(LOG_ERR, "Connect script failed");
505 		setdtr(ttyfd, FALSE);
506 		goto fail;
507 	    }
508 
509 	    syslog(LOG_INFO, "Serial connection established.");
510 	    sleep(1);		/* give it time to set up its terminal */
511 	}
512 
513 	set_up_tty(ttyfd, 0);
514 
515 	/* reopen tty if necessary to wait for carrier */
516 	if (connector == NULL && modem) {
517 	    while ((i = open(devnam, O_RDWR)) < 0) {
518 		if (errno != EINTR)
519 		    syslog(LOG_ERR, "Failed to reopen %s: %m", devnam);
520 		if (!persist || errno != EINTR || hungup || kill_link)
521 		    goto fail;
522 	    }
523 	    close(i);
524 	}
525 
526 	/* run welcome script, if any */
527 	if (welcomer && welcomer[0]) {
528 	    if (device_script(welcomer, ttyfd, ttyfd) < 0)
529 		syslog(LOG_WARNING, "Welcome script failed");
530 	}
531 
532 	/* set up the serial device as a ppp interface */
533 	establish_ppp(ttyfd);
534 
535 	if (!demand) {
536 
537 	    syslog(LOG_INFO, "Using interface ppp%d", ifunit);
538 	    (void) snprintf(ifname, sizeof ifname, "ppp%d", ifunit);
539 	    script_setenv("IFNAME", ifname);
540 
541 	    create_pidfile();	/* write pid to file */
542 	}
543 
544 	/*
545 	 * Start opening the connection and wait for
546 	 * incoming events (reply, timeout, etc.).
547 	 */
548 	syslog(LOG_NOTICE, "Connect: %s <--> %s", ifname, devnam);
549 	lcp_lowerup(0);
550 	lcp_open(0);		/* Start protocol */
551 	for (phase = PHASE_ESTABLISH; phase != PHASE_DEAD; ) {
552 	    wait_input(timeleft(&timo));
553 	    calltimeout();
554 	    get_input();
555 	    if (kill_link) {
556 		lcp_close(0, "User request");
557 		kill_link = 0;
558 	    }
559 	    if (open_ccp_flag) {
560 		if (phase == PHASE_NETWORK) {
561 		    ccp_fsm[0].flags = OPT_RESTART; /* clears OPT_SILENT */
562 		    (*ccp_protent.open)(0);
563 		}
564 		open_ccp_flag = 0;
565 	    }
566 	    reap_kids();	/* Don't leave dead kids lying around */
567 	}
568 
569 	/*
570 	 * If we may want to bring the link up again, transfer
571 	 * the ppp unit back to the loopback.  Set the
572 	 * real serial device back to its normal mode of operation.
573 	 */
574 	clean_check();
575 	if (demand)
576 	    restore_loop();
577 	disestablish_ppp(ttyfd);
578 
579 	/*
580 	 * Run disconnector script, if requested.
581 	 * XXX we may not be able to do this if the line has hung up!
582 	 */
583 	if (disconnector && !hungup) {
584 	    set_up_tty(ttyfd, 1);
585 	    if (device_script(disconnector, ttyfd, ttyfd) < 0) {
586 		syslog(LOG_WARNING, "disconnect script failed");
587 	    } else {
588 		syslog(LOG_INFO, "Serial link disconnected.");
589 	    }
590 	}
591 
592     fail:
593 	if (ttyfd >= 0)
594 	    close_tty();
595 	if (locked) {
596 	    unlock();
597 	    locked = 0;
598 	}
599 
600 	if (!demand) {
601 	    if (pidfilename[0] != 0
602 		&& unlink(pidfilename) < 0 && errno != ENOENT)
603 		syslog(LOG_WARNING, "unable to delete pid file: %m");
604 	    pidfilename[0] = 0;
605 	}
606 
607 	if (!persist)
608 	    die(1);
609 
610 	if (holdoff > 0 && need_holdoff) {
611 	    phase = PHASE_HOLDOFF;
612 	    TIMEOUT(holdoff_end, NULL, holdoff);
613 	    do {
614 		wait_time(timeleft(&timo));
615 		calltimeout();
616 		if (kill_link) {
617 		    if (!persist)
618 			die(0);
619 		    kill_link = 0;
620 		    phase = PHASE_DORMANT; /* allow signal to end holdoff */
621 		}
622 		reap_kids();
623 	    } while (phase == PHASE_HOLDOFF);
624 	}
625     }
626 
627     die(0);
628     return 0;
629 }
630 
631 /*
632  * detach - detach us from the controlling terminal.
633  */
634 void
635 detach()
636 {
637     if (detached)
638 	return;
639     if (daemon(0, 0) < 0) {
640 	perror("Couldn't detach from controlling terminal");
641 	die(1);
642     }
643     detached = 1;
644     pid = getpid();
645     /* update pid file if it has been written already */
646     if (pidfilename[0])
647 	create_pidfile();
648 }
649 
650 /*
651  * Create a file containing our process ID.
652  */
653 static void
654 create_pidfile()
655 {
656     FILE *pidfile;
657 
658     (void) snprintf(pidfilename, sizeof pidfilename,
659 	"%s%s.pid", _PATH_VARRUN, ifname);
660     if ((pidfile = fopen(pidfilename, "w")) != NULL) {
661 	fprintf(pidfile, "%ld\n", (long)pid);
662 	(void) fclose(pidfile);
663     } else {
664 	syslog(LOG_ERR, "Failed to create pid file %s: %m", pidfilename);
665 	pidfilename[0] = 0;
666     }
667 }
668 
669 /*
670  * holdoff_end - called via a timeout when the holdoff period ends.
671  */
672 static void
673 holdoff_end(arg)
674     void *arg;
675 {
676     phase = PHASE_DORMANT;
677 }
678 
679 /*
680  * get_input - called when incoming data is available.
681  */
682 static void
683 get_input()
684 {
685     int len, i;
686     u_char *p;
687     u_short protocol;
688     struct protent *protp;
689 
690     p = inpacket_buf;	/* point to beginning of packet buffer */
691 
692     len = read_packet(inpacket_buf);
693     if (len < 0)
694 	return;
695 
696     if (len == 0) {
697 	syslog(LOG_NOTICE, "Modem hangup");
698 	hungup = 1;
699 	lcp_lowerdown(0);	/* serial link is no longer available */
700 	link_terminated(0);
701 	return;
702     }
703 
704     if (debug /*&& (debugflags & DBG_INPACKET)*/)
705 	log_packet(p, len, "rcvd ", LOG_DEBUG);
706 
707     if (len < PPP_HDRLEN) {
708 	MAINDEBUG((LOG_INFO, "io(): Received short packet."));
709 	return;
710     }
711 
712     p += 2;				/* Skip address and control */
713     GETSHORT(protocol, p);
714     len -= PPP_HDRLEN;
715 
716     /*
717      * Toss all non-LCP packets unless LCP is OPEN.
718      */
719     if (protocol != PPP_LCP && lcp_fsm[0].state != OPENED) {
720 	MAINDEBUG((LOG_INFO,
721 		   "get_input: Received non-LCP packet when LCP not open."));
722 	return;
723     }
724 
725     /*
726      * Until we get past the authentication phase, toss all packets
727      * except LCP, LQR and authentication packets.
728      */
729     if (phase <= PHASE_AUTHENTICATE
730 	&& !(protocol == PPP_LCP || protocol == PPP_LQR
731 	|| protocol == PPP_PAP || protocol == PPP_CHAP)) {
732 	MAINDEBUG((LOG_INFO, "get_input: discarding proto 0x%x in phase %d",
733 		   protocol, phase));
734 	return;
735     }
736 
737     /*
738      * Upcall the proper protocol input routine.
739      */
740     for (i = 0; (protp = protocols[i]) != NULL; ++i) {
741 	if (protp->protocol == protocol && protp->enabled_flag) {
742 	    (*protp->input)(0, p, len);
743 	    return;
744 	}
745 	if (protocol == (protp->protocol & ~0x8000) && protp->enabled_flag
746 	    && protp->datainput != NULL) {
747 	    (*protp->datainput)(0, p, len);
748 	    return;
749 	}
750     }
751 
752     if (debug)
753     	syslog(LOG_WARNING, "Unsupported protocol (0x%x) received", protocol);
754     lcp_sprotrej(0, p - PPP_HDRLEN, len + PPP_HDRLEN);
755 }
756 
757 
758 /*
759  * quit - Clean up state and exit (with an error indication).
760  */
761 void
762 quit()
763 {
764     die(1);
765 }
766 
767 /*
768  * die - like quit, except we can specify an exit status.
769  */
770 void
771 die(status)
772     int status;
773 {
774     struct syslog_data sdata = SYSLOG_DATA_INIT;
775 
776     cleanup();
777     syslog_r(LOG_INFO, &sdata, "Exit.");
778     _exit(status);
779 }
780 
781 /*
782  * cleanup - restore anything which needs to be restored before we exit
783  */
784 /* ARGSUSED */
785 static void
786 cleanup()
787 {
788     sys_cleanup();
789 
790     if (ttyfd >= 0)
791 	close_tty();
792 
793     if (pidfilename[0] != 0 && unlink(pidfilename) < 0 && errno != ENOENT)
794 	syslog(LOG_WARNING, "unable to delete pid file: %m");
795     pidfilename[0] = 0;
796 
797     if (locked)
798 	unlock();
799 }
800 
801 /*
802  * close_tty - restore the terminal device and close it.
803  */
804 static void
805 close_tty()
806 {
807     disestablish_ppp(ttyfd);
808 
809     /* drop dtr to hang up */
810     if (modem) {
811 	setdtr(ttyfd, FALSE);
812 	/*
813 	 * This sleep is in case the serial port has CLOCAL set by default,
814 	 * and consequently will reassert DTR when we close the device.
815 	 */
816 	sleep(1);
817     }
818 
819     restore_tty(ttyfd);
820 
821     if (tty_mode != (mode_t) -1)
822 	fchmod(ttyfd, tty_mode);
823 
824     close(ttyfd);
825     ttyfd = -1;
826 }
827 
828 
829 struct	callout {
830     struct timeval	c_time;		/* time at which to call routine */
831     void		*c_arg;		/* argument to routine */
832     void		(*c_func)(void *); /* routine */
833     struct		callout *c_next;
834 };
835 
836 static struct callout *callout = NULL;	/* Callout list */
837 static struct timeval timenow;		/* Current time */
838 
839 /*
840  * timeout - Schedule a timeout.
841  *
842  * Note that this timeout takes the number of seconds, NOT hz (as in
843  * the kernel).
844  */
845 void
846 timeout(func, arg, time)
847     void (*func)(void *);
848     void *arg;
849     int time;
850 {
851     struct callout *newp, *p, **pp;
852 
853     MAINDEBUG((LOG_DEBUG, "Timeout %lx:%lx in %d seconds.",
854 	       (long) func, (long) arg, time));
855 
856     /*
857      * Allocate timeout.
858      */
859     if ((newp = (struct callout *) malloc(sizeof(struct callout))) == NULL) {
860 	syslog(LOG_ERR, "Out of memory in timeout()!");
861 	die(1);
862     }
863     newp->c_arg = arg;
864     newp->c_func = func;
865     gettimeofday(&timenow, NULL);
866     newp->c_time.tv_sec = timenow.tv_sec + time;
867     newp->c_time.tv_usec = timenow.tv_usec;
868 
869     /*
870      * Find correct place and link it in.
871      */
872     for (pp = &callout; (p = *pp); pp = &p->c_next)
873 	if (newp->c_time.tv_sec < p->c_time.tv_sec
874 	    || (newp->c_time.tv_sec == p->c_time.tv_sec
875 		&& newp->c_time.tv_usec < p->c_time.tv_sec))
876 	    break;
877     newp->c_next = p;
878     *pp = newp;
879 }
880 
881 
882 /*
883  * untimeout - Unschedule a timeout.
884  */
885 void
886 untimeout(func, arg)
887     void (*func)(void *);
888     void *arg;
889 {
890     struct callout **copp, *freep;
891 
892     MAINDEBUG((LOG_DEBUG, "Untimeout %lx:%lx.", (long) func, (long) arg));
893 
894     /*
895      * Find first matching timeout and remove it from the list.
896      */
897     for (copp = &callout; (freep = *copp); copp = &freep->c_next)
898 	if (freep->c_func == func && freep->c_arg == arg) {
899 	    *copp = freep->c_next;
900 	    (void) free((char *) freep);
901 	    break;
902 	}
903 }
904 
905 
906 /*
907  * calltimeout - Call any timeout routines which are now due.
908  */
909 static void
910 calltimeout()
911 {
912     struct callout *p;
913 
914     while (callout != NULL) {
915 	p = callout;
916 
917 	if (gettimeofday(&timenow, NULL) < 0) {
918 	    syslog(LOG_ERR, "Failed to get time of day: %m");
919 	    die(1);
920 	}
921 	if (!(p->c_time.tv_sec < timenow.tv_sec
922 	      || (p->c_time.tv_sec == timenow.tv_sec
923 		  && p->c_time.tv_usec <= timenow.tv_usec)))
924 	    break;		/* no, it's not time yet */
925 
926 	callout = p->c_next;
927 	(*p->c_func)(p->c_arg);
928 
929 	free((char *) p);
930     }
931 }
932 
933 
934 /*
935  * timeleft - return the length of time until the next timeout is due.
936  */
937 static struct timeval *
938 timeleft(tvp)
939     struct timeval *tvp;
940 {
941     if (callout == NULL)
942 	return NULL;
943 
944     gettimeofday(&timenow, NULL);
945     tvp->tv_sec = callout->c_time.tv_sec - timenow.tv_sec;
946     tvp->tv_usec = callout->c_time.tv_usec - timenow.tv_usec;
947     if (tvp->tv_usec < 0) {
948 	tvp->tv_usec += 1000000;
949 	tvp->tv_sec -= 1;
950     }
951     if (tvp->tv_sec < 0)
952 	tvp->tv_sec = tvp->tv_usec = 0;
953 
954     return tvp;
955 }
956 
957 
958 /*
959  * kill_my_pg - send a signal to our process group, and ignore it ourselves.
960  */
961 static void
962 kill_my_pg(sig)
963     int sig;
964 {
965     struct sigaction act, oldact;
966 
967     act.sa_handler = SIG_IGN;
968     act.sa_flags = 0;
969     kill(0, sig);
970     sigaction(sig, &act, &oldact);
971     sigaction(sig, &oldact, NULL);
972 }
973 
974 
975 /*
976  * hup - Catch SIGHUP signal.
977  *
978  * Indicates that the physical layer has been disconnected.
979  * We don't rely on this indication; if the user has sent this
980  * signal, we just take the link down.
981  */
982 static void
983 hup(sig)
984     int sig;
985 {
986     int save_errno = errno;
987     struct syslog_data sdata = SYSLOG_DATA_INIT;
988 
989     if (crashed)
990 	_exit(127);
991     syslog_r(LOG_INFO, &sdata, "Hangup (SIGHUP)");
992     kill_link = 1;
993     if (conn_running)
994 	/* Send the signal to the [dis]connector process(es) also */
995 	kill_my_pg(sig);
996     errno = save_errno;
997 }
998 
999 
1000 /*
1001  * term - Catch SIGTERM signal and SIGINT signal (^C/del).
1002  *
1003  * Indicates that we should initiate a graceful disconnect and exit.
1004  */
1005 /*ARGSUSED*/
1006 static void
1007 term(sig)
1008     int sig;
1009 {
1010     int save_errno = errno;
1011     struct syslog_data sdata = SYSLOG_DATA_INIT;
1012 
1013     if (crashed)
1014 	_exit(127);
1015     syslog_r(LOG_INFO, &sdata, "Terminating on signal %d.", sig);
1016     persist = 0;		/* don't try to restart */
1017     kill_link = 1;
1018     if (conn_running)
1019 	/* Send the signal to the [dis]connector process(es) also */
1020 	kill_my_pg(sig);
1021     errno = save_errno;
1022 }
1023 
1024 
1025 /*
1026  * chld - Catch SIGCHLD signal.
1027  * Calls reap_kids to get status for any dead kids.
1028  */
1029 static void
1030 chld(sig)
1031     int sig;
1032 {
1033     int save_errno = errno;
1034 
1035     reap_kids();		/* XXX somewhat unsafe */
1036     errno = save_errno;
1037 }
1038 
1039 
1040 /*
1041  * toggle_debug - Catch SIGUSR1 signal.
1042  *
1043  * Toggle debug flag.
1044  */
1045 /*ARGSUSED*/
1046 static void
1047 toggle_debug(sig)
1048     int sig;
1049 {
1050     debug = !debug;
1051     if (debug) {
1052 	setlogmask(LOG_UPTO(LOG_DEBUG));	/* XXX safe, but wrong */
1053     } else {
1054 	setlogmask(LOG_UPTO(LOG_WARNING));	/* XXX safe, but wrong */
1055     }
1056 }
1057 
1058 
1059 /*
1060  * open_ccp - Catch SIGUSR2 signal.
1061  *
1062  * Try to (re)negotiate compression.
1063  */
1064 /*ARGSUSED*/
1065 static void
1066 open_ccp(sig)
1067     int sig;
1068 {
1069     open_ccp_flag = 1;
1070 }
1071 
1072 
1073 /*
1074  * bad_signal - We've caught a fatal signal.  Clean up state and exit.
1075  */
1076 static void
1077 bad_signal(sig)
1078     int sig;
1079 {
1080     struct syslog_data sdata = SYSLOG_DATA_INIT;
1081 
1082     if (crashed)
1083 	_exit(127);
1084     crashed = 1;
1085     syslog_r(LOG_ERR, &sdata, "Fatal signal %d", sig);
1086     if (conn_running)
1087 	kill_my_pg(SIGTERM);
1088     die(1);					/* XXX unsafe! */
1089 }
1090 
1091 
1092 /*
1093  * device_script - run a program to connect or disconnect the
1094  * serial device.
1095  */
1096 static int
1097 device_script(program, in, out)
1098     char *program;
1099     int in, out;
1100 {
1101     pid_t pid;
1102     int status;
1103     int errfd;
1104     gid_t gid;
1105     uid_t uid;
1106 
1107     conn_running = 1;
1108     pid = fork();
1109 
1110     if (pid < 0) {
1111 	conn_running = 0;
1112 	syslog(LOG_ERR, "Failed to create child process: %m");
1113 	die(1);
1114     }
1115 
1116     if (pid == 0) {
1117 	sys_close();
1118 	closelog();
1119 	if (in == out) {
1120 	    if (in != 0) {
1121 		dup2(in, 0);
1122 		close(in);
1123 	    }
1124 	    dup2(0, 1);
1125 	} else {
1126 	    if (out == 0)
1127 		out = dup(out);
1128 	    if (in != 0) {
1129 		dup2(in, 0);
1130 		close(in);
1131 	    }
1132 	    if (out != 1) {
1133 		dup2(out, 1);
1134 		close(out);
1135 	    }
1136 	}
1137 	if (nodetach == 0) {
1138 	    close(2);
1139 	    errfd = open(_PATH_CONNERRS, O_WRONLY | O_APPEND | O_CREAT, 0600);
1140 	    if (errfd >= 0 && errfd != 2) {
1141 		dup2(errfd, 2);
1142 		close(errfd);
1143 	    }
1144 	}
1145 
1146 	/* revoke privs */
1147 	gid = getgid();
1148 	uid = getuid();
1149 	if (setresgid(gid, gid, gid) == -1 || setresuid(uid, uid, uid) == -1) {
1150 		syslog(LOG_ERR, "revoke privileges: %s", strerror(errno));
1151 		_exit(1);
1152 	}
1153 
1154 	execl("/bin/sh", "sh", "-c", program, (char *)0);
1155 	syslog(LOG_ERR, "could not exec /bin/sh: %m");
1156 	_exit(99);
1157 	/* NOTREACHED */
1158     }
1159 
1160     while (waitpid(pid, &status, 0) < 0) {
1161 	if (errno == EINTR)
1162 	    continue;
1163 	syslog(LOG_ERR, "error waiting for (dis)connection process: %m");
1164 	die(1);
1165     }
1166     conn_running = 0;
1167 
1168     return (status == 0 ? 0 : -1);
1169 }
1170 
1171 
1172 /*
1173  * run-program - execute a program with given arguments,
1174  * but don't wait for it.
1175  * If the program can't be executed, logs an error unless
1176  * must_exist is 0 and the program file doesn't exist.
1177  */
1178 int
1179 run_program(prog, args, must_exist)
1180     char *prog;
1181     char **args;
1182     int must_exist;
1183 {
1184     pid_t pid;
1185     uid_t uid;
1186     gid_t gid;
1187 
1188     pid = fork();
1189     if (pid == -1) {
1190 	syslog(LOG_ERR, "Failed to create child process for %s: %m", prog);
1191 	return -1;
1192     }
1193     if (pid == 0) {
1194 	int new_fd;
1195 
1196 	/* Leave the current location */
1197 	(void) setsid();    /* No controlling tty. */
1198 	(void) umask (S_IRWXG|S_IRWXO);
1199 	(void) chdir ("/"); /* no current directory. */
1200 
1201 	/* revoke privs */
1202 	uid = getuid();
1203 	gid = getgid();
1204 	if (setresgid(gid, gid, gid) == -1 || setresuid(uid, uid, uid) == -1) {
1205 		syslog(LOG_ERR, "revoke privileges: %s", strerror(errno));
1206 		_exit(1);
1207 	}
1208 
1209 	/* Ensure that nothing of our device environment is inherited. */
1210 	sys_close();
1211 	closelog();
1212 	close (0);
1213 	close (1);
1214 	close (2);
1215 	close (ttyfd);  /* tty interface to the ppp device */
1216 
1217 	/* Don't pass handles to the PPP device, even by accident. */
1218 	new_fd = open (_PATH_DEVNULL, O_RDWR);
1219 	if (new_fd >= 0) {
1220 	    if (new_fd != 0) {
1221 		dup2  (new_fd, 0); /* stdin <- /dev/null */
1222 		close (new_fd);
1223 	    }
1224 	    dup2 (0, 1); /* stdout -> /dev/null */
1225 	    dup2 (0, 2); /* stderr -> /dev/null */
1226 	}
1227 
1228 #ifdef BSD
1229 	/* Force the priority back to zero if pppd is running higher. */
1230 	if (setpriority (PRIO_PROCESS, 0, 0) < 0)
1231 	    syslog (LOG_WARNING, "can't reset priority to 0: %m");
1232 #endif
1233 
1234 	/* SysV recommends a second fork at this point. */
1235 
1236 	/* run the program; give it a null environment */
1237 	execve(prog, args, script_env);
1238 	if (must_exist || errno != ENOENT)
1239 	    syslog(LOG_WARNING, "Can't execute %s: %m", prog);
1240 	_exit(1);
1241     }
1242     MAINDEBUG((LOG_DEBUG, "Script %s started; pid = %ld", prog, (long)pid));
1243     ++n_children;
1244     return 0;
1245 }
1246 
1247 
1248 /*
1249  * reap_kids - get status from any dead child processes,
1250  * and log a message for abnormal terminations.
1251  */
1252 static void
1253 reap_kids()
1254 {
1255     int status;
1256     pid_t pid;
1257 
1258     if (n_children == 0)
1259 	return;
1260     if ((pid = waitpid(-1, &status, WNOHANG)) == -1) {
1261 	if (errno != ECHILD)
1262 	    syslog(LOG_ERR, "Error waiting for child process: %m");
1263 	return;
1264     }
1265     if (pid > 0) {
1266 	--n_children;
1267 	if (WIFSIGNALED(status)) {
1268 	    syslog(LOG_WARNING, "Child process %ld terminated with signal %d",
1269 		   (long)pid, WTERMSIG(status));
1270 	}
1271     }
1272 }
1273 
1274 
1275 /*
1276  * log_packet - format a packet and log it.
1277  */
1278 
1279 char line[256];			/* line to be logged accumulated here */
1280 char *linep;
1281 
1282 void
1283 log_packet(p, len, prefix, level)
1284     u_char *p;
1285     int len;
1286     char *prefix;
1287     int level;
1288 {
1289     strlcpy(line, prefix, sizeof line);
1290     linep = line + strlen(line);
1291     format_packet(p, len, pr_log, NULL);
1292     if (linep != line)
1293 	syslog(level, "%s", line);
1294 }
1295 
1296 /*
1297  * format_packet - make a readable representation of a packet,
1298  * calling `printer(arg, format, ...)' to output it.
1299  */
1300 void
1301 format_packet(p, len, printer, arg)
1302     u_char *p;
1303     int len;
1304     void (*printer)(void *, char *, ...);
1305     void *arg;
1306 {
1307     int i, n;
1308     u_short proto;
1309     u_char x;
1310     struct protent *protp;
1311 
1312     if (len >= PPP_HDRLEN && p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) {
1313 	p += 2;
1314 	GETSHORT(proto, p);
1315 	len -= PPP_HDRLEN;
1316 	for (i = 0; (protp = protocols[i]) != NULL; ++i)
1317 	    if (proto == protp->protocol)
1318 		break;
1319 	if (protp != NULL) {
1320 	    printer(arg, "[%s", protp->name);
1321 	    n = (*protp->printpkt)(p, len, printer, arg);
1322 	    printer(arg, "]");
1323 	    p += n;
1324 	    len -= n;
1325 	} else {
1326 	    printer(arg, "[proto=0x%x]", proto);
1327 	}
1328     }
1329 
1330     for (; len > 0; --len) {
1331 	GETCHAR(x, p);
1332 	printer(arg, " %.2x", x);
1333     }
1334 }
1335 
1336 static void
1337 pr_log(void *arg, char *fmt, ...)
1338 {
1339     int n;
1340     va_list pvar;
1341     char buf[256];
1342 
1343     va_start(pvar, fmt);
1344 
1345     n = vfmtmsg(buf, sizeof(buf), fmt, pvar);
1346     va_end(pvar);
1347 
1348     if (linep + n + 1 > line + sizeof(line)) {
1349 	syslog(LOG_DEBUG, "%s", line);
1350 	linep = line;
1351     }
1352     strlcpy(linep, buf, line + sizeof line - linep);
1353     linep += n;
1354 }
1355 
1356 /*
1357  * print_string - print a readable representation of a string using
1358  * printer.
1359  */
1360 void
1361 print_string(p, len, printer, arg)
1362     char *p;
1363     int len;
1364     void (*printer)(void *, char *, ...);
1365     void *arg;
1366 {
1367     int c;
1368 
1369     printer(arg, "\"");
1370     for (; len > 0; --len) {
1371 	c = *p++;
1372 	if (' ' <= c && c <= '~') {
1373 	    if (c == '\\' || c == '"')
1374 		printer(arg, "\\");
1375 	    printer(arg, "%c", c);
1376 	} else {
1377 	    switch (c) {
1378 	    case '\n':
1379 		printer(arg, "\\n");
1380 		break;
1381 	    case '\r':
1382 		printer(arg, "\\r");
1383 		break;
1384 	    case '\t':
1385 		printer(arg, "\\t");
1386 		break;
1387 	    default:
1388 		printer(arg, "\\%.3o", c);
1389 	    }
1390 	}
1391     }
1392     printer(arg, "\"");
1393 }
1394 
1395 /*
1396  * novm - log an error message saying we ran out of memory, and die.
1397  */
1398 void
1399 novm(msg)
1400     char *msg;
1401 {
1402     syslog(LOG_ERR, "Virtual memory exhausted allocating %s", msg);
1403     die(1);
1404 }
1405 
1406 /*
1407  * fmtmsg - format a message into a buffer.  Like snprintf except we
1408  * also specify the length of the output buffer, and we handle
1409  * %m (error message) and %I (IP address) formats.
1410  * Doesn't do floating-point formats.
1411  * Returns the number of chars put into buf.
1412  */
1413 int
1414 fmtmsg(char *buf, int buflen, char *fmt, ...)
1415 {
1416     va_list args;
1417     int n;
1418 
1419     va_start(args, fmt);
1420     n = vfmtmsg(buf, buflen, fmt, args);
1421     va_end(args);
1422     return n;
1423 }
1424 
1425 /*
1426  * vfmtmsg - like fmtmsg, takes a va_list instead of a list of args.
1427  */
1428 #define OUTCHAR(c)	(buflen > 0? (--buflen, *buf++ = (c)): 0)
1429 
1430 int
1431 vfmtmsg(buf, buflen, fmt, args)
1432     char *buf;
1433     int buflen;
1434     char *fmt;
1435     va_list args;
1436 {
1437     int c, i, n;
1438     int width, prec, fillch;
1439     int base, len, neg, quoted;
1440     unsigned long val = 0;
1441     char *str, *f, *buf0;
1442     unsigned char *p;
1443     char num[32];
1444     time_t t;
1445     static char hexchars[] = "0123456789abcdef";
1446 
1447     buf0 = buf;
1448     --buflen;
1449     while (buflen > 0) {
1450 	for (f = fmt; *f != '%' && *f != 0; ++f)
1451 	    ;
1452 	if (f > fmt) {
1453 	    len = f - fmt;
1454 	    if (len > buflen)
1455 		len = buflen;
1456 	    memcpy(buf, fmt, len);
1457 	    buf += len;
1458 	    buflen -= len;
1459 	    fmt = f;
1460 	}
1461 	if (*fmt == 0)
1462 	    break;
1463 	c = *++fmt;
1464 	width = prec = 0;
1465 	fillch = ' ';
1466 	if (c == '0') {
1467 	    fillch = '0';
1468 	    c = *++fmt;
1469 	}
1470 	if (c == '*') {
1471 	    width = va_arg(args, int);
1472 	    c = *++fmt;
1473 	} else {
1474 	    while (isdigit(c)) {
1475 		width = width * 10 + c - '0';
1476 		c = *++fmt;
1477 	    }
1478 	}
1479 	if (c == '.') {
1480 	    c = *++fmt;
1481 	    if (c == '*') {
1482 		prec = va_arg(args, int);
1483 		c = *++fmt;
1484 	    } else {
1485 		while (isdigit(c)) {
1486 		    prec = prec * 10 + c - '0';
1487 		    c = *++fmt;
1488 		}
1489 	    }
1490 	}
1491 	str = 0;
1492 	base = 0;
1493 	neg = 0;
1494 	++fmt;
1495 	switch (c) {
1496 	case 'd':
1497 	    i = va_arg(args, int);
1498 	    if (i < 0) {
1499 		neg = 1;
1500 		val = -i;
1501 	    } else
1502 		val = i;
1503 	    base = 10;
1504 	    break;
1505 	case 'o':
1506 	    val = va_arg(args, unsigned int);
1507 	    base = 8;
1508 	    break;
1509 	case 'x':
1510 	    val = va_arg(args, unsigned int);
1511 	    base = 16;
1512 	    break;
1513 	case 'p':
1514 	    val = (unsigned long) va_arg(args, void *);
1515 	    base = 16;
1516 	    neg = 2;
1517 	    break;
1518 	case 's':
1519 	    str = va_arg(args, char *);
1520 	    break;
1521 	case 'c':
1522 	    num[0] = va_arg(args, int);
1523 	    num[1] = 0;
1524 	    str = num;
1525 	    break;
1526 	case 'm':
1527 	    str = strerror(errno);
1528 	    break;
1529 	case 'I':
1530 	    str = ip_ntoa(va_arg(args, u_int32_t));
1531 	    break;
1532 	case 't':
1533 	    time(&t);
1534 	    str = ctime(&t);
1535 	    str += 4;		/* chop off the day name */
1536 	    str[15] = 0;	/* chop off year and newline */
1537 	    break;
1538 	case 'v':		/* "visible" string */
1539 	case 'q':		/* quoted string */
1540 	    quoted = c == 'q';
1541 	    p = va_arg(args, unsigned char *);
1542 	    if (fillch == '0' && prec > 0) {
1543 		n = prec;
1544 	    } else {
1545 		n = strlen((char *)p);
1546 		if (prec > 0 && prec < n)
1547 		    n = prec;
1548 	    }
1549 	    while (n > 0 && buflen > 0) {
1550 		c = *p++;
1551 		--n;
1552 		if (!quoted && c >= 0x80) {
1553 		    OUTCHAR('M');
1554 		    OUTCHAR('-');
1555 		    c -= 0x80;
1556 		}
1557 		if (quoted && (c == '"' || c == '\\'))
1558 		    OUTCHAR('\\');
1559 		if (c < 0x20 || (0x7f <= c && c < 0xa0)) {
1560 		    if (quoted) {
1561 			OUTCHAR('\\');
1562 			switch (c) {
1563 			case '\t':	OUTCHAR('t');	break;
1564 			case '\n':	OUTCHAR('n');	break;
1565 			case '\b':	OUTCHAR('b');	break;
1566 			case '\f':	OUTCHAR('f');	break;
1567 			default:
1568 			    OUTCHAR('x');
1569 			    OUTCHAR(hexchars[c >> 4]);
1570 			    OUTCHAR(hexchars[c & 0xf]);
1571 			}
1572 		    } else {
1573 			if (c == '\t')
1574 			    OUTCHAR(c);
1575 			else {
1576 			    OUTCHAR('^');
1577 			    OUTCHAR(c ^ 0x40);
1578 			}
1579 		    }
1580 		} else
1581 		    OUTCHAR(c);
1582 	    }
1583 	    continue;
1584 	default:
1585 	    *buf++ = '%';
1586 	    if (c != '%')
1587 		--fmt;		/* so %z outputs %z etc. */
1588 	    --buflen;
1589 	    continue;
1590 	}
1591 	if (base != 0) {
1592 	    str = num + sizeof(num);
1593 	    *--str = 0;
1594 	    while (str > num + neg) {
1595 		*--str = hexchars[val % base];
1596 		val = val / base;
1597 		if (--prec <= 0 && val == 0)
1598 		    break;
1599 	    }
1600 	    switch (neg) {
1601 	    case 1:
1602 		*--str = '-';
1603 		break;
1604 	    case 2:
1605 		*--str = 'x';
1606 		*--str = '0';
1607 		break;
1608 	    }
1609 	    len = num + sizeof(num) - 1 - str;
1610 	} else {
1611 	    len = strlen(str);
1612 	    if (prec > 0 && len > prec)
1613 		len = prec;
1614 	}
1615 	if (width > 0) {
1616 	    if (width > buflen)
1617 		width = buflen;
1618 	    if ((n = width - len) > 0) {
1619 		buflen -= n;
1620 		for (; n > 0; --n)
1621 		    *buf++ = fillch;
1622 	    }
1623 	}
1624 	if (len > buflen)
1625 	    len = buflen;
1626 	memcpy(buf, str, len);
1627 	buf += len;
1628 	buflen -= len;
1629     }
1630     *buf = 0;
1631     return buf - buf0;
1632 }
1633 
1634 /*
1635  * script_setenv - set an environment variable value to be used
1636  * for scripts that we run (e.g. ip-up, auth-up, etc.)
1637  */
1638 void
1639 script_setenv(var, value)
1640     char *var, *value;
1641 {
1642     int vl = strlen(var);
1643     int i;
1644     char *p, *newstring;
1645 
1646     if (asprintf(&newstring, "%s=%s", var, value) == -1)
1647 	novm("script_setenv");
1648 
1649     /* check if this variable is already set */
1650     if (script_env != 0) {
1651 	for (i = 0; (p = script_env[i]) != 0; ++i) {
1652 	    if (strncmp(p, var, vl) == 0 && p[vl] == '=') {
1653 		free(p);
1654 		script_env[i] = newstring;
1655 		return;
1656 	    }
1657 	}
1658     } else {
1659 	i = 0;
1660 	script_env = (char **) calloc(16, sizeof(char *));
1661 	if (script_env == 0)
1662 	    novm("script_setenv");
1663 	s_env_nalloc = 16;
1664     }
1665 
1666     /* reallocate script_env with more space if needed */
1667     if (i + 1 >= s_env_nalloc) {
1668 	int new_n = i + 17;
1669 	char **newenv = (char **) realloc((void *)script_env,
1670 					  new_n * sizeof(char *));
1671 	if (newenv == 0)
1672 	    novm("script_setenv");
1673 	script_env = newenv;
1674 	s_env_nalloc = new_n;
1675     }
1676 
1677     script_env[i] = newstring;
1678     script_env[i+1] = 0;
1679 }
1680 
1681 /*
1682  * script_unsetenv - remove a variable from the environment
1683  * for scripts.
1684  */
1685 void
1686 script_unsetenv(var)
1687     char *var;
1688 {
1689     int vl = strlen(var);
1690     int i;
1691     char *p;
1692 
1693     if (script_env == 0)
1694 	return;
1695     for (i = 0; (p = script_env[i]) != 0; ++i) {
1696 	if (strncmp(p, var, vl) == 0 && p[vl] == '=') {
1697 	    free(p);
1698 	    while ((script_env[i] = script_env[i+1]) != 0)
1699 		++i;
1700 	    break;
1701 	}
1702     }
1703 }
1704