main.c revision 1.33 
1/*	$OpenBSD: main.c,v 1.33 2002/02/16 21:28:07 millert 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
23#if 0
24static char rcsid[] = "Id: main.c,v 1.49 1998/05/05 05:24:17 paulus Exp $";
25#else
26static char rcsid[] = "$OpenBSD: main.c,v 1.33 2002/02/16 21:28:07 millert Exp $";
27#endif
28#endif
29
30#include <stdio.h>
31#include <ctype.h>
32#include <stdlib.h>
33#include <string.h>
34#include <unistd.h>
35#include <signal.h>
36#include <errno.h>
37#include <fcntl.h>
38#include <syslog.h>
39#include <netdb.h>
40#include <utmp.h>
41#include <pwd.h>
42#include <sys/param.h>
43#include <sys/types.h>
44#include <sys/wait.h>
45#include <sys/time.h>
46#include <sys/resource.h>
47#include <sys/stat.h>
48#include <sys/socket.h>
49#include <net/if.h>
50
51#include "pppd.h"
52#include "magic.h"
53#include "fsm.h"
54#include "lcp.h"
55#include "ipcp.h"
56#include "upap.h"
57#include "chap.h"
58#include "ccp.h"
59#include "pathnames.h"
60#include "patchlevel.h"
61
62#ifdef CBCP_SUPPORT
63#include "cbcp.h"
64#endif
65
66#if defined(SUNOS4)
67extern char *strerror();
68#endif
69
70#ifdef IPX_CHANGE
71#include "ipxcp.h"
72#endif /* IPX_CHANGE */
73#ifdef AT_CHANGE
74#include "atcp.h"
75#endif
76
77/* interface vars */
78char ifname[IFNAMSIZ];		/* Interface name */
79int ifunit;			/* Interface unit number */
80
81char *progname;			/* Name of this program */
82char hostname[MAXHOSTNAMELEN];	/* Our hostname */
83static char pidfilename[MAXPATHLEN];	/* name of pid file */
84static char default_devnam[MAXPATHLEN];	/* name of default device */
85static pid_t pid;		/* Our pid */
86static uid_t uid;		/* Our real user-id */
87static int conn_running;	/* we have a [dis]connector running */
88static int crashed = 0;
89
90int ttyfd = -1;			/* Serial port file descriptor */
91mode_t tty_mode = -1;		/* Original access permissions to tty */
92int baud_rate;			/* Actual bits/second for serial device */
93int hungup;			/* terminal has been hung up */
94int privileged;			/* we're running as real uid root */
95int need_holdoff;		/* need holdoff period before restarting */
96int detached;			/* have detached from terminal */
97
98int phase;			/* where the link is at */
99int kill_link;
100int open_ccp_flag;
101
102char **script_env;		/* Env. variable values for scripts */
103int s_env_nalloc;		/* # words avail at script_env */
104
105u_char outpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for outgoing packet */
106u_char inpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for incoming packet */
107
108static int n_children;		/* # child processes still running */
109
110static int locked;		/* lock() has succeeded */
111
112char *no_ppp_msg = "Sorry - this system lacks PPP kernel support\n";
113
114/* Prototypes for procedures local to this file. */
115
116static void create_pidfile(void);
117static void cleanup(void);
118static void close_tty(void);
119static void get_input(void);
120static void calltimeout(void);
121static struct timeval *timeleft(struct timeval *);
122static void kill_my_pg(int);
123static void hup(int);
124static void term(int);
125static void chld(int);
126static void toggle_debug(int);
127static void open_ccp(int);
128static void bad_signal(int);
129static void holdoff_end(void *);
130static int device_script(char *, int, int);
131static void reap_kids(void);
132static void pr_log(void *, char *, ...);
133
134extern	char	*ttyname(int);
135extern	char	*getlogin(void);
136int main(int, char *[]);
137
138#ifdef ultrix
139#undef	O_NONBLOCK
140#define	O_NONBLOCK	O_NDELAY
141#endif
142
143#ifdef ULTRIX
144#define setlogmask(x)
145#endif
146
147/*
148 * PPP Data Link Layer "protocol" table.
149 * One entry per supported protocol.
150 * The last entry must be NULL.
151 */
152struct protent *protocols[] = {
153    &lcp_protent,
154    &pap_protent,
155    &chap_protent,
156#ifdef CBCP_SUPPORT
157    &cbcp_protent,
158#endif
159    &ipcp_protent,
160    &ccp_protent,
161#ifdef IPX_CHANGE
162    &ipxcp_protent,
163#endif
164#ifdef AT_CHANGE
165    &atcp_protent,
166#endif
167    NULL
168};
169
170int
171main(argc, argv)
172    int argc;
173    char *argv[];
174{
175    int i, fdflags;
176    struct sigaction sa;
177    char *p;
178    struct passwd *pw;
179    struct timeval timo;
180    sigset_t mask;
181    struct protent *protp;
182    struct stat statbuf;
183    char numbuf[16];
184
185    phase = PHASE_INITIALIZE;
186    p = ttyname(0);
187    if (p)
188	strcpy(devnam, p);
189    strcpy(default_devnam, devnam);
190
191    script_env = NULL;
192
193    /* Initialize syslog facilities */
194#ifdef ULTRIX
195    openlog("pppd", LOG_PID);
196#else
197    openlog("pppd", LOG_PID | LOG_NDELAY, LOG_PPP);
198    setlogmask(LOG_UPTO(LOG_INFO));
199#endif
200
201    if (gethostname(hostname, sizeof hostname) < 0 ) {
202	option_error("Couldn't get hostname: %m");
203	die(1);
204    }
205
206    uid = getuid();
207    privileged = uid == 0;
208    sprintf(numbuf, "%u", uid);
209    script_setenv("UID", numbuf);
210
211    /*
212     * Initialize to the standard option set, then parse, in order,
213     * the system options file, the user's options file,
214     * the tty's options file, and the command line arguments.
215     */
216    for (i = 0; (protp = protocols[i]) != NULL; ++i)
217	(*protp->init)(0);
218
219    progname = *argv;
220
221    if (!options_from_file(_PATH_SYSOPTIONS, !privileged, 0, 1)
222	|| !options_from_user())
223	exit(1);
224    scan_args(argc-1, argv+1);	/* look for tty name on command line */
225    if (!options_for_tty()
226	|| !parse_args(argc-1, argv+1))
227	exit(1);
228
229    /*
230     * Check that we are running as root.
231     */
232    if (geteuid() != 0) {
233	option_error("must be root to run %s, since it is not setuid-root",
234		     argv[0]);
235	die(1);
236    }
237
238    if (!ppp_available()) {
239	option_error(no_ppp_msg);
240	exit(1);
241    }
242
243    /*
244     * Check that the options given are valid and consistent.
245     */
246    sys_check_options();
247    auth_check_options();
248    for (i = 0; (protp = protocols[i]) != NULL; ++i)
249	if (protp->check_options != NULL)
250	    (*protp->check_options)();
251    if (demand && connector == 0) {
252	option_error("connect script required for demand-dialling\n");
253	exit(1);
254    }
255
256    script_setenv("DEVICE", devnam);
257    sprintf(numbuf, "%d", baud_rate);
258    script_setenv("SPEED", numbuf);
259
260    /*
261     * If the user has specified the default device name explicitly,
262     * pretend they hadn't.
263     */
264    if (!default_device && strcmp(devnam, default_devnam) == 0)
265	default_device = 1;
266    if (default_device)
267	nodetach = 1;
268
269    /*
270     * Initialize system-dependent stuff and magic number package.
271     */
272    sys_init();
273    magic_init();
274    if (debug)
275	setlogmask(LOG_UPTO(LOG_DEBUG));
276
277    /*
278     * Detach ourselves from the terminal, if required,
279     * and identify who is running us.
280     */
281    if (nodetach == 0)
282	detach();
283    pid = getpid();
284    p = getlogin();
285    if (p == NULL) {
286	pw = getpwuid(uid);
287	if (pw != NULL && pw->pw_name != NULL)
288	    p = pw->pw_name;
289	else
290	    p = "(unknown)";
291    }
292    syslog(LOG_NOTICE, "pppd %s.%d%s started by %s, uid %u",
293	   VERSION, PATCHLEVEL, IMPLEMENTATION, p, uid);
294
295    /*
296     * Compute mask of all interesting signals and install signal handlers
297     * for each.  Only one signal handler may be active at a time.  Therefore,
298     * all other signals should be masked when any handler is executing.
299     */
300    sigemptyset(&mask);
301    sigaddset(&mask, SIGHUP);
302    sigaddset(&mask, SIGINT);
303    sigaddset(&mask, SIGTERM);
304    sigaddset(&mask, SIGCHLD);
305
306#define SIGNAL(s, handler)	{ \
307	sa.sa_handler = handler; \
308	if (sigaction(s, &sa, NULL) < 0) { \
309	    syslog(LOG_ERR, "Couldn't establish signal handler (%d): %m", s); \
310	    die(1); \
311	} \
312    }
313
314    sa.sa_mask = mask;
315    sa.sa_flags = 0;
316    SIGNAL(SIGHUP, hup);		/* Hangup */
317    SIGNAL(SIGINT, term);		/* Interrupt */
318    SIGNAL(SIGTERM, term);		/* Terminate */
319    SIGNAL(SIGCHLD, chld);
320
321    SIGNAL(SIGUSR1, toggle_debug);	/* Toggle debug flag */
322    SIGNAL(SIGUSR2, open_ccp);		/* Reopen CCP */
323
324    /*
325     * Install a handler for other signals which would otherwise
326     * cause pppd to exit without cleaning up.
327     */
328    SIGNAL(SIGABRT, bad_signal);
329    SIGNAL(SIGALRM, bad_signal);
330    SIGNAL(SIGFPE, bad_signal);
331    SIGNAL(SIGILL, bad_signal);
332    SIGNAL(SIGPIPE, bad_signal);
333    SIGNAL(SIGQUIT, bad_signal);
334    SIGNAL(SIGSEGV, bad_signal);
335#ifdef SIGBUS
336    SIGNAL(SIGBUS, bad_signal);
337#endif
338#ifdef SIGEMT
339    SIGNAL(SIGEMT, bad_signal);
340#endif
341#ifdef SIGPOLL
342    SIGNAL(SIGPOLL, bad_signal);
343#endif
344#ifdef SIGPROF
345    SIGNAL(SIGPROF, bad_signal);
346#endif
347#ifdef SIGSYS
348    SIGNAL(SIGSYS, bad_signal);
349#endif
350#ifdef SIGTRAP
351    SIGNAL(SIGTRAP, bad_signal);
352#endif
353#ifdef SIGVTALRM
354    SIGNAL(SIGVTALRM, bad_signal);
355#endif
356#ifdef SIGXCPU
357    SIGNAL(SIGXCPU, bad_signal);
358#endif
359#ifdef SIGXFSZ
360    SIGNAL(SIGXFSZ, bad_signal);
361#endif
362
363    /*
364     * Apparently we can get a SIGPIPE when we call syslog, if
365     * syslogd has died and been restarted.  Ignoring it seems
366     * be sufficient.
367     */
368    signal(SIGPIPE, SIG_IGN);
369
370    /*
371     * If we're doing dial-on-demand, set up the interface now.
372     */
373    if (demand) {
374	/*
375	 * Open the loopback channel and set it up to be the ppp interface.
376	 */
377	open_ppp_loopback();
378
379	syslog(LOG_INFO, "Using interface ppp%d", ifunit);
380	(void) sprintf(ifname, "ppp%d", ifunit);
381	script_setenv("IFNAME", ifname);
382
383	create_pidfile();	/* write pid to file */
384
385	/*
386	 * Configure the interface and mark it up, etc.
387	 */
388	demand_conf();
389    }
390
391    for (;;) {
392
393	need_holdoff = 1;
394
395	if (demand) {
396	    /*
397	     * Don't do anything until we see some activity.
398	     */
399	    phase = PHASE_DORMANT;
400	    kill_link = 0;
401	    demand_unblock();
402	    for (;;) {
403		wait_loop_output(timeleft(&timo));
404		calltimeout();
405		if (kill_link) {
406		    if (!persist)
407			die(0);
408		    kill_link = 0;
409		}
410		if (get_loop_output())
411		    break;
412		reap_kids();
413	    }
414
415	    /*
416	     * Now we want to bring up the link.
417	     */
418	    demand_drop();
419	    syslog(LOG_INFO, "Starting link");
420	}
421
422	/*
423	 * Lock the device if we've been asked to.
424	 */
425	if (lockflag && !default_device) {
426	    if (lock(devnam) < 0)
427		goto fail;
428	    locked = 1;
429	}
430
431	/*
432	 * Open the serial device and set it up to be the ppp interface.
433	 * First we open it in non-blocking mode so we can set the
434	 * various termios flags appropriately.  If we aren't dialling
435	 * out and we want to use the modem lines, we reopen it later
436	 * in order to wait for the carrier detect signal from the modem.
437	 */
438	while ((ttyfd = open(devnam, O_NONBLOCK | O_RDWR, 0)) < 0) {
439	    if (errno != EINTR)
440		syslog(LOG_ERR, "Failed to open %s: %m", devnam);
441	    if (!persist || errno != EINTR)
442		goto fail;
443	}
444	if ((fdflags = fcntl(ttyfd, F_GETFL)) == -1
445	    || fcntl(ttyfd, F_SETFL, fdflags & ~O_NONBLOCK) < 0)
446	    syslog(LOG_WARNING,
447		   "Couldn't reset non-blocking mode on device: %m");
448
449	hungup = 0;
450	kill_link = 0;
451
452	/*
453	 * Do the equivalent of `mesg n' to stop broadcast messages.
454	 */
455	if (fstat(ttyfd, &statbuf) < 0
456	    || fchmod(ttyfd, statbuf.st_mode & ~(S_IWGRP | S_IWOTH)) < 0) {
457	    syslog(LOG_WARNING,
458		   "Couldn't restrict write permissions to %s: %m", devnam);
459	} else
460	    tty_mode = statbuf.st_mode;
461
462	/* run connection script */
463	if (connector && connector[0]) {
464	    MAINDEBUG((LOG_INFO, "Connecting with <%s>", connector));
465
466	    /*
467	     * Set line speed, flow control, etc.
468	     * On most systems we set CLOCAL for now so that we can talk
469	     * to the modem before carrier comes up.  But this has the
470	     * side effect that we might miss it if CD drops before we
471	     * get to clear CLOCAL below.  On systems where we can talk
472	     * successfully to the modem with CLOCAL clear and CD down,
473	     * we can clear CLOCAL at this point.
474	     */
475	    set_up_tty(ttyfd, (modem_chat == 0));
476
477	    /* drop dtr to hang up in case modem is off hook */
478	    if (!default_device && modem) {
479		setdtr(ttyfd, FALSE);
480		sleep(1);
481		setdtr(ttyfd, TRUE);
482	    }
483
484	    if (device_script(connector, ttyfd, ttyfd) < 0) {
485		syslog(LOG_ERR, "Connect script failed");
486		setdtr(ttyfd, FALSE);
487		goto fail;
488	    }
489
490	    syslog(LOG_INFO, "Serial connection established.");
491	    sleep(1);		/* give it time to set up its terminal */
492	}
493
494	set_up_tty(ttyfd, 0);
495
496	/* reopen tty if necessary to wait for carrier */
497	if (connector == NULL && modem) {
498	    while ((i = open(devnam, O_RDWR)) < 0) {
499		if (errno != EINTR)
500		    syslog(LOG_ERR, "Failed to reopen %s: %m", devnam);
501		if (!persist || errno != EINTR || hungup || kill_link)
502		    goto fail;
503	    }
504	    close(i);
505	}
506
507	/* run welcome script, if any */
508	if (welcomer && welcomer[0]) {
509	    if (device_script(welcomer, ttyfd, ttyfd) < 0)
510		syslog(LOG_WARNING, "Welcome script failed");
511	}
512
513	/* set up the serial device as a ppp interface */
514	establish_ppp(ttyfd);
515
516	if (!demand) {
517
518	    syslog(LOG_INFO, "Using interface ppp%d", ifunit);
519	    (void) sprintf(ifname, "ppp%d", ifunit);
520	    script_setenv("IFNAME", ifname);
521
522	    create_pidfile();	/* write pid to file */
523	}
524
525	/*
526	 * Start opening the connection and wait for
527	 * incoming events (reply, timeout, etc.).
528	 */
529	syslog(LOG_NOTICE, "Connect: %s <--> %s", ifname, devnam);
530	lcp_lowerup(0);
531	lcp_open(0);		/* Start protocol */
532	for (phase = PHASE_ESTABLISH; phase != PHASE_DEAD; ) {
533	    wait_input(timeleft(&timo));
534	    calltimeout();
535	    get_input();
536	    if (kill_link) {
537		lcp_close(0, "User request");
538		kill_link = 0;
539	    }
540	    if (open_ccp_flag) {
541		if (phase == PHASE_NETWORK) {
542		    ccp_fsm[0].flags = OPT_RESTART; /* clears OPT_SILENT */
543		    (*ccp_protent.open)(0);
544		}
545		open_ccp_flag = 0;
546	    }
547	    reap_kids();	/* Don't leave dead kids lying around */
548	}
549
550	/*
551	 * If we may want to bring the link up again, transfer
552	 * the ppp unit back to the loopback.  Set the
553	 * real serial device back to its normal mode of operation.
554	 */
555	clean_check();
556	if (demand)
557	    restore_loop();
558	disestablish_ppp(ttyfd);
559
560	/*
561	 * Run disconnector script, if requested.
562	 * XXX we may not be able to do this if the line has hung up!
563	 */
564	if (disconnector && !hungup) {
565	    set_up_tty(ttyfd, 1);
566	    if (device_script(disconnector, ttyfd, ttyfd) < 0) {
567		syslog(LOG_WARNING, "disconnect script failed");
568	    } else {
569		syslog(LOG_INFO, "Serial link disconnected.");
570	    }
571	}
572
573    fail:
574	if (ttyfd >= 0)
575	    close_tty();
576	if (locked) {
577	    unlock();
578	    locked = 0;
579	}
580
581	if (!demand) {
582	    if (pidfilename[0] != 0
583		&& unlink(pidfilename) < 0 && errno != ENOENT)
584		syslog(LOG_WARNING, "unable to delete pid file: %m");
585	    pidfilename[0] = 0;
586	}
587
588	if (!persist)
589	    die(1);
590
591	if (holdoff > 0 && need_holdoff) {
592	    phase = PHASE_HOLDOFF;
593	    TIMEOUT(holdoff_end, NULL, holdoff);
594	    do {
595		wait_time(timeleft(&timo));
596		calltimeout();
597		if (kill_link) {
598		    if (!persist)
599			die(0);
600		    kill_link = 0;
601		    phase = PHASE_DORMANT; /* allow signal to end holdoff */
602		}
603		reap_kids();
604	    } while (phase == PHASE_HOLDOFF);
605	}
606    }
607
608    die(0);
609    return 0;
610}
611
612/*
613 * detach - detach us from the controlling terminal.
614 */
615void
616detach()
617{
618    if (detached)
619	return;
620    if (daemon(0, 0) < 0) {
621	perror("Couldn't detach from controlling terminal");
622	die(1);
623    }
624    detached = 1;
625    pid = getpid();
626    /* update pid file if it has been written already */
627    if (pidfilename[0])
628	create_pidfile();
629}
630
631/*
632 * Create a file containing our process ID.
633 */
634static void
635create_pidfile()
636{
637    FILE *pidfile;
638
639    (void) sprintf(pidfilename, "%s%s.pid", _PATH_VARRUN, ifname);
640    if ((pidfile = fopen(pidfilename, "w")) != NULL) {
641	fprintf(pidfile, "%d\n", pid);
642	(void) fclose(pidfile);
643    } else {
644	syslog(LOG_ERR, "Failed to create pid file %s: %m", pidfilename);
645	pidfilename[0] = 0;
646    }
647}
648
649/*
650 * holdoff_end - called via a timeout when the holdoff period ends.
651 */
652static void
653holdoff_end(arg)
654    void *arg;
655{
656    phase = PHASE_DORMANT;
657}
658
659/*
660 * get_input - called when incoming data is available.
661 */
662static void
663get_input()
664{
665    int len, i;
666    u_char *p;
667    u_short protocol;
668    struct protent *protp;
669
670    p = inpacket_buf;	/* point to beginning of packet buffer */
671
672    len = read_packet(inpacket_buf);
673    if (len < 0)
674	return;
675
676    if (len == 0) {
677	syslog(LOG_NOTICE, "Modem hangup");
678	hungup = 1;
679	lcp_lowerdown(0);	/* serial link is no longer available */
680	link_terminated(0);
681	return;
682    }
683
684    if (debug /*&& (debugflags & DBG_INPACKET)*/)
685	log_packet(p, len, "rcvd ", LOG_DEBUG);
686
687    if (len < PPP_HDRLEN) {
688	MAINDEBUG((LOG_INFO, "io(): Received short packet."));
689	return;
690    }
691
692    p += 2;				/* Skip address and control */
693    GETSHORT(protocol, p);
694    len -= PPP_HDRLEN;
695
696    /*
697     * Toss all non-LCP packets unless LCP is OPEN.
698     */
699    if (protocol != PPP_LCP && lcp_fsm[0].state != OPENED) {
700	MAINDEBUG((LOG_INFO,
701		   "get_input: Received non-LCP packet when LCP not open."));
702	return;
703    }
704
705    /*
706     * Until we get past the authentication phase, toss all packets
707     * except LCP, LQR and authentication packets.
708     */
709    if (phase <= PHASE_AUTHENTICATE
710	&& !(protocol == PPP_LCP || protocol == PPP_LQR
711	|| protocol == PPP_PAP || protocol == PPP_CHAP)) {
712	MAINDEBUG((LOG_INFO, "get_input: discarding proto 0x%x in phase %d",
713		   protocol, phase));
714	return;
715    }
716
717    /*
718     * Upcall the proper protocol input routine.
719     */
720    for (i = 0; (protp = protocols[i]) != NULL; ++i) {
721	if (protp->protocol == protocol && protp->enabled_flag) {
722	    (*protp->input)(0, p, len);
723	    return;
724	}
725	if (protocol == (protp->protocol & ~0x8000) && protp->enabled_flag
726	    && protp->datainput != NULL) {
727	    (*protp->datainput)(0, p, len);
728	    return;
729	}
730    }
731
732    if (debug)
733    	syslog(LOG_WARNING, "Unsupported protocol (0x%x) received", protocol);
734    lcp_sprotrej(0, p - PPP_HDRLEN, len + PPP_HDRLEN);
735}
736
737
738/*
739 * quit - Clean up state and exit (with an error indication).
740 */
741void
742quit()
743{
744    die(1);
745}
746
747/*
748 * die - like quit, except we can specify an exit status.
749 */
750void
751die(status)
752    int status;
753{
754    struct syslog_data sdata = SYSLOG_DATA_INIT;
755
756    cleanup();
757    syslog_r(LOG_INFO, &sdata, "Exit.");
758    _exit(status);
759}
760
761/*
762 * cleanup - restore anything which needs to be restored before we exit
763 */
764/* ARGSUSED */
765static void
766cleanup()
767{
768    sys_cleanup();
769
770    if (ttyfd >= 0)
771	close_tty();
772
773    if (pidfilename[0] != 0 && unlink(pidfilename) < 0 && errno != ENOENT)
774	syslog(LOG_WARNING, "unable to delete pid file: %m");
775    pidfilename[0] = 0;
776
777    if (locked)
778	unlock();
779}
780
781/*
782 * close_tty - restore the terminal device and close it.
783 */
784static void
785close_tty()
786{
787    disestablish_ppp(ttyfd);
788
789    /* drop dtr to hang up */
790    if (modem) {
791	setdtr(ttyfd, FALSE);
792	/*
793	 * This sleep is in case the serial port has CLOCAL set by default,
794	 * and consequently will reassert DTR when we close the device.
795	 */
796	sleep(1);
797    }
798
799    restore_tty(ttyfd);
800
801    if (tty_mode != (mode_t) -1)
802	chmod(devnam, tty_mode);
803
804    close(ttyfd);
805    ttyfd = -1;
806}
807
808
809struct	callout {
810    struct timeval	c_time;		/* time at which to call routine */
811    void		*c_arg;		/* argument to routine */
812    void		(*c_func)(void *); /* routine */
813    struct		callout *c_next;
814};
815
816static struct callout *callout = NULL;	/* Callout list */
817static struct timeval timenow;		/* Current time */
818
819/*
820 * timeout - Schedule a timeout.
821 *
822 * Note that this timeout takes the number of seconds, NOT hz (as in
823 * the kernel).
824 */
825void
826timeout(func, arg, time)
827    void (*func)(void *);
828    void *arg;
829    int time;
830{
831    struct callout *newp, *p, **pp;
832
833    MAINDEBUG((LOG_DEBUG, "Timeout %lx:%lx in %d seconds.",
834	       (long) func, (long) arg, time));
835
836    /*
837     * Allocate timeout.
838     */
839    if ((newp = (struct callout *) malloc(sizeof(struct callout))) == NULL) {
840	syslog(LOG_ERR, "Out of memory in timeout()!");
841	die(1);
842    }
843    newp->c_arg = arg;
844    newp->c_func = func;
845    gettimeofday(&timenow, NULL);
846    newp->c_time.tv_sec = timenow.tv_sec + time;
847    newp->c_time.tv_usec = timenow.tv_usec;
848
849    /*
850     * Find correct place and link it in.
851     */
852    for (pp = &callout; (p = *pp); pp = &p->c_next)
853	if (newp->c_time.tv_sec < p->c_time.tv_sec
854	    || (newp->c_time.tv_sec == p->c_time.tv_sec
855		&& newp->c_time.tv_usec < p->c_time.tv_sec))
856	    break;
857    newp->c_next = p;
858    *pp = newp;
859}
860
861
862/*
863 * untimeout - Unschedule a timeout.
864 */
865void
866untimeout(func, arg)
867    void (*func)(void *);
868    void *arg;
869{
870    struct callout **copp, *freep;
871
872    MAINDEBUG((LOG_DEBUG, "Untimeout %lx:%lx.", (long) func, (long) arg));
873
874    /*
875     * Find first matching timeout and remove it from the list.
876     */
877    for (copp = &callout; (freep = *copp); copp = &freep->c_next)
878	if (freep->c_func == func && freep->c_arg == arg) {
879	    *copp = freep->c_next;
880	    (void) free((char *) freep);
881	    break;
882	}
883}
884
885
886/*
887 * calltimeout - Call any timeout routines which are now due.
888 */
889static void
890calltimeout()
891{
892    struct callout *p;
893
894    while (callout != NULL) {
895	p = callout;
896
897	if (gettimeofday(&timenow, NULL) < 0) {
898	    syslog(LOG_ERR, "Failed to get time of day: %m");
899	    die(1);
900	}
901	if (!(p->c_time.tv_sec < timenow.tv_sec
902	      || (p->c_time.tv_sec == timenow.tv_sec
903		  && p->c_time.tv_usec <= timenow.tv_usec)))
904	    break;		/* no, it's not time yet */
905
906	callout = p->c_next;
907	(*p->c_func)(p->c_arg);
908
909	free((char *) p);
910    }
911}
912
913
914/*
915 * timeleft - return the length of time until the next timeout is due.
916 */
917static struct timeval *
918timeleft(tvp)
919    struct timeval *tvp;
920{
921    if (callout == NULL)
922	return NULL;
923
924    gettimeofday(&timenow, NULL);
925    tvp->tv_sec = callout->c_time.tv_sec - timenow.tv_sec;
926    tvp->tv_usec = callout->c_time.tv_usec - timenow.tv_usec;
927    if (tvp->tv_usec < 0) {
928	tvp->tv_usec += 1000000;
929	tvp->tv_sec -= 1;
930    }
931    if (tvp->tv_sec < 0)
932	tvp->tv_sec = tvp->tv_usec = 0;
933
934    return tvp;
935}
936
937
938/*
939 * kill_my_pg - send a signal to our process group, and ignore it ourselves.
940 */
941static void
942kill_my_pg(sig)
943    int sig;
944{
945    struct sigaction act, oldact;
946
947    act.sa_handler = SIG_IGN;
948    act.sa_flags = 0;
949    kill(0, sig);
950    sigaction(sig, &act, &oldact);
951    sigaction(sig, &oldact, NULL);
952}
953
954
955/*
956 * hup - Catch SIGHUP signal.
957 *
958 * Indicates that the physical layer has been disconnected.
959 * We don't rely on this indication; if the user has sent this
960 * signal, we just take the link down.
961 */
962static void
963hup(sig)
964    int sig;
965{
966    int save_errno = errno;
967    struct syslog_data sdata = SYSLOG_DATA_INIT;
968
969    if (crashed)
970	_exit(127);
971    syslog_r(LOG_INFO, &sdata, "Hangup (SIGHUP)");
972    kill_link = 1;
973    if (conn_running)
974	/* Send the signal to the [dis]connector process(es) also */
975	kill_my_pg(sig);
976    errno = save_errno;
977}
978
979
980/*
981 * term - Catch SIGTERM signal and SIGINT signal (^C/del).
982 *
983 * Indicates that we should initiate a graceful disconnect and exit.
984 */
985/*ARGSUSED*/
986static void
987term(sig)
988    int sig;
989{
990    int save_errno = errno;
991    struct syslog_data sdata = SYSLOG_DATA_INIT;
992
993    if (crashed)
994	_exit(127);
995    syslog_r(LOG_INFO, &sdata, "Terminating on signal %d.", sig);
996    persist = 0;		/* don't try to restart */
997    kill_link = 1;
998    if (conn_running)
999	/* Send the signal to the [dis]connector process(es) also */
1000	kill_my_pg(sig);
1001    errno = save_errno;
1002}
1003
1004
1005/*
1006 * chld - Catch SIGCHLD signal.
1007 * Calls reap_kids to get status for any dead kids.
1008 */
1009static void
1010chld(sig)
1011    int sig;
1012{
1013    int save_errno = errno;
1014
1015    reap_kids();		/* XXX somewhat unsafe */
1016    errno = save_errno;
1017}
1018
1019
1020/*
1021 * toggle_debug - Catch SIGUSR1 signal.
1022 *
1023 * Toggle debug flag.
1024 */
1025/*ARGSUSED*/
1026static void
1027toggle_debug(sig)
1028    int sig;
1029{
1030    debug = !debug;
1031    if (debug) {
1032	setlogmask(LOG_UPTO(LOG_DEBUG));	/* XXX safe, but wrong */
1033    } else {
1034	setlogmask(LOG_UPTO(LOG_WARNING));	/* XXX safe, but wrong */
1035    }
1036}
1037
1038
1039/*
1040 * open_ccp - Catch SIGUSR2 signal.
1041 *
1042 * Try to (re)negotiate compression.
1043 */
1044/*ARGSUSED*/
1045static void
1046open_ccp(sig)
1047    int sig;
1048{
1049    open_ccp_flag = 1;
1050}
1051
1052
1053/*
1054 * bad_signal - We've caught a fatal signal.  Clean up state and exit.
1055 */
1056static void
1057bad_signal(sig)
1058    int sig;
1059{
1060    struct syslog_data sdata = SYSLOG_DATA_INIT;
1061
1062    if (crashed)
1063	_exit(127);
1064    crashed = 1;
1065    syslog_r(LOG_ERR, &sdata, "Fatal signal %d", sig);
1066    if (conn_running)
1067	kill_my_pg(SIGTERM);
1068    die(1);					/* XXX unsafe! */
1069}
1070
1071
1072/*
1073 * device_script - run a program to connect or disconnect the
1074 * serial device.
1075 */
1076static int
1077device_script(program, in, out)
1078    char *program;
1079    int in, out;
1080{
1081    int pid;
1082    int status;
1083    int errfd;
1084
1085    conn_running = 1;
1086    pid = fork();
1087
1088    if (pid < 0) {
1089	conn_running = 0;
1090	syslog(LOG_ERR, "Failed to create child process: %m");
1091	die(1);
1092    }
1093
1094    if (pid == 0) {
1095	sys_close();
1096	closelog();
1097	if (in == out) {
1098	    if (in != 0) {
1099		dup2(in, 0);
1100		close(in);
1101	    }
1102	    dup2(0, 1);
1103	} else {
1104	    if (out == 0)
1105		out = dup(out);
1106	    if (in != 0) {
1107		dup2(in, 0);
1108		close(in);
1109	    }
1110	    if (out != 1) {
1111		dup2(out, 1);
1112		close(out);
1113	    }
1114	}
1115	if (nodetach == 0) {
1116	    close(2);
1117	    errfd = open(_PATH_CONNERRS, O_WRONLY | O_APPEND | O_CREAT, 0600);
1118	    if (errfd >= 0 && errfd != 2) {
1119		dup2(errfd, 2);
1120		close(errfd);
1121	    }
1122	}
1123	/* revoke privs */
1124	seteuid(getuid());
1125	setuid(getuid());
1126	setegid(getgid());
1127	setgid(getgid());
1128	execl("/bin/sh", "sh", "-c", program, (char *)0);
1129	syslog(LOG_ERR, "could not exec /bin/sh: %m");
1130	_exit(99);
1131	/* NOTREACHED */
1132    }
1133
1134    while (waitpid(pid, &status, 0) < 0) {
1135	if (errno == EINTR)
1136	    continue;
1137	syslog(LOG_ERR, "error waiting for (dis)connection process: %m");
1138	die(1);
1139    }
1140    conn_running = 0;
1141
1142    return (status == 0 ? 0 : -1);
1143}
1144
1145
1146/*
1147 * run-program - execute a program with given arguments,
1148 * but don't wait for it.
1149 * If the program can't be executed, logs an error unless
1150 * must_exist is 0 and the program file doesn't exist.
1151 */
1152int
1153run_program(prog, args, must_exist)
1154    char *prog;
1155    char **args;
1156    int must_exist;
1157{
1158    int pid;
1159
1160    pid = fork();
1161    if (pid == -1) {
1162	syslog(LOG_ERR, "Failed to create child process for %s: %m", prog);
1163	return -1;
1164    }
1165    if (pid == 0) {
1166	int new_fd;
1167
1168	/* Leave the current location */
1169	(void) setsid();    /* No controlling tty. */
1170	(void) umask (S_IRWXG|S_IRWXO);
1171	(void) chdir ("/"); /* no current directory. */
1172	setuid(geteuid());
1173	setgid(getegid());
1174
1175	/* Ensure that nothing of our device environment is inherited. */
1176	sys_close();
1177	closelog();
1178	close (0);
1179	close (1);
1180	close (2);
1181	close (ttyfd);  /* tty interface to the ppp device */
1182
1183	/* Don't pass handles to the PPP device, even by accident. */
1184	new_fd = open (_PATH_DEVNULL, O_RDWR);
1185	if (new_fd >= 0) {
1186	    if (new_fd != 0) {
1187		dup2  (new_fd, 0); /* stdin <- /dev/null */
1188		close (new_fd);
1189	    }
1190	    dup2 (0, 1); /* stdout -> /dev/null */
1191	    dup2 (0, 2); /* stderr -> /dev/null */
1192	}
1193
1194#ifdef BSD
1195	/* Force the priority back to zero if pppd is running higher. */
1196	if (setpriority (PRIO_PROCESS, 0, 0) < 0)
1197	    syslog (LOG_WARNING, "can't reset priority to 0: %m");
1198#endif
1199
1200	/* SysV recommends a second fork at this point. */
1201
1202	/* run the program; give it a null environment */
1203	execve(prog, args, script_env);
1204	if (must_exist || errno != ENOENT)
1205	    syslog(LOG_WARNING, "Can't execute %s: %m", prog);
1206	_exit(1);
1207    }
1208    MAINDEBUG((LOG_DEBUG, "Script %s started; pid = %d", prog, pid));
1209    ++n_children;
1210    return 0;
1211}
1212
1213
1214/*
1215 * reap_kids - get status from any dead child processes,
1216 * and log a message for abnormal terminations.
1217 */
1218static void
1219reap_kids()
1220{
1221    int pid, status;
1222
1223    if (n_children == 0)
1224	return;
1225    if ((pid = waitpid(-1, &status, WNOHANG)) == -1) {
1226	if (errno != ECHILD)
1227	    syslog(LOG_ERR, "Error waiting for child process: %m");
1228	return;
1229    }
1230    if (pid > 0) {
1231	--n_children;
1232	if (WIFSIGNALED(status)) {
1233	    syslog(LOG_WARNING, "Child process %d terminated with signal %d",
1234		   pid, WTERMSIG(status));
1235	}
1236    }
1237}
1238
1239
1240/*
1241 * log_packet - format a packet and log it.
1242 */
1243
1244char line[256];			/* line to be logged accumulated here */
1245char *linep;
1246
1247void
1248log_packet(p, len, prefix, level)
1249    u_char *p;
1250    int len;
1251    char *prefix;
1252    int level;
1253{
1254    strcpy(line, prefix);
1255    linep = line + strlen(line);
1256    format_packet(p, len, pr_log, NULL);
1257    if (linep != line)
1258	syslog(level, "%s", line);
1259}
1260
1261/*
1262 * format_packet - make a readable representation of a packet,
1263 * calling `printer(arg, format, ...)' to output it.
1264 */
1265void
1266format_packet(p, len, printer, arg)
1267    u_char *p;
1268    int len;
1269    void (*printer)(void *, char *, ...);
1270    void *arg;
1271{
1272    int i, n;
1273    u_short proto;
1274    u_char x;
1275    struct protent *protp;
1276
1277    if (len >= PPP_HDRLEN && p[0] == PPP_ALLSTATIONS && p[1] == PPP_UI) {
1278	p += 2;
1279	GETSHORT(proto, p);
1280	len -= PPP_HDRLEN;
1281	for (i = 0; (protp = protocols[i]) != NULL; ++i)
1282	    if (proto == protp->protocol)
1283		break;
1284	if (protp != NULL) {
1285	    printer(arg, "[%s", protp->name);
1286	    n = (*protp->printpkt)(p, len, printer, arg);
1287	    printer(arg, "]");
1288	    p += n;
1289	    len -= n;
1290	} else {
1291	    printer(arg, "[proto=0x%x]", proto);
1292	}
1293    }
1294
1295    for (; len > 0; --len) {
1296	GETCHAR(x, p);
1297	printer(arg, " %.2x", x);
1298    }
1299}
1300
1301static void
1302pr_log __V((void *arg, char *fmt, ...))
1303{
1304    int n;
1305    va_list pvar;
1306    char buf[256];
1307
1308#ifdef __STDC__
1309    va_start(pvar, fmt);
1310#else
1311    void *arg;
1312    char *fmt;
1313    va_start(pvar);
1314    arg = va_arg(pvar, void *);
1315    fmt = va_arg(pvar, char *);
1316#endif
1317
1318    n = vfmtmsg(buf, sizeof(buf), fmt, pvar);
1319    va_end(pvar);
1320
1321    if (linep + n + 1 > line + sizeof(line)) {
1322	syslog(LOG_DEBUG, "%s", line);
1323	linep = line;
1324    }
1325    strcpy(linep, buf);
1326    linep += n;
1327}
1328
1329/*
1330 * print_string - print a readable representation of a string using
1331 * printer.
1332 */
1333void
1334print_string(p, len, printer, arg)
1335    char *p;
1336    int len;
1337    void (*printer)(void *, char *, ...);
1338    void *arg;
1339{
1340    int c;
1341
1342    printer(arg, "\"");
1343    for (; len > 0; --len) {
1344	c = *p++;
1345	if (' ' <= c && c <= '~') {
1346	    if (c == '\\' || c == '"')
1347		printer(arg, "\\");
1348	    printer(arg, "%c", c);
1349	} else {
1350	    switch (c) {
1351	    case '\n':
1352		printer(arg, "\\n");
1353		break;
1354	    case '\r':
1355		printer(arg, "\\r");
1356		break;
1357	    case '\t':
1358		printer(arg, "\\t");
1359		break;
1360	    default:
1361		printer(arg, "\\%.3o", c);
1362	    }
1363	}
1364    }
1365    printer(arg, "\"");
1366}
1367
1368/*
1369 * novm - log an error message saying we ran out of memory, and die.
1370 */
1371void
1372novm(msg)
1373    char *msg;
1374{
1375    syslog(LOG_ERR, "Virtual memory exhausted allocating %s", msg);
1376    die(1);
1377}
1378
1379/*
1380 * fmtmsg - format a message into a buffer.  Like sprintf except we
1381 * also specify the length of the output buffer, and we handle
1382 * %r (recursive format), %m (error message) and %I (IP address) formats.
1383 * Doesn't do floating-point formats.
1384 * Returns the number of chars put into buf.
1385 */
1386int
1387fmtmsg __V((char *buf, int buflen, char *fmt, ...))
1388{
1389    va_list args;
1390    int n;
1391
1392#ifdef __STDC__
1393    va_start(args, fmt);
1394#else
1395    char *buf;
1396    int buflen;
1397    char *fmt;
1398    va_start(args);
1399    buf = va_arg(args, char *);
1400    buflen = va_arg(args, int);
1401    fmt = va_arg(args, char *);
1402#endif
1403    n = vfmtmsg(buf, buflen, fmt, args);
1404    va_end(args);
1405    return n;
1406}
1407
1408/*
1409 * vfmtmsg - like fmtmsg, takes a va_list instead of a list of args.
1410 */
1411#define OUTCHAR(c)	(buflen > 0? (--buflen, *buf++ = (c)): 0)
1412
1413int
1414vfmtmsg(buf, buflen, fmt, args)
1415    char *buf;
1416    int buflen;
1417    char *fmt;
1418    va_list args;
1419{
1420    int c, i, n;
1421    int width, prec, fillch;
1422    int base, len, neg, quoted;
1423    unsigned long val = 0;
1424    char *str, *f, *buf0;
1425    unsigned char *p;
1426    char num[32];
1427    time_t t;
1428    static char hexchars[] = "0123456789abcdef";
1429
1430    buf0 = buf;
1431    --buflen;
1432    while (buflen > 0) {
1433	for (f = fmt; *f != '%' && *f != 0; ++f)
1434	    ;
1435	if (f > fmt) {
1436	    len = f - fmt;
1437	    if (len > buflen)
1438		len = buflen;
1439	    memcpy(buf, fmt, len);
1440	    buf += len;
1441	    buflen -= len;
1442	    fmt = f;
1443	}
1444	if (*fmt == 0)
1445	    break;
1446	c = *++fmt;
1447	width = prec = 0;
1448	fillch = ' ';
1449	if (c == '0') {
1450	    fillch = '0';
1451	    c = *++fmt;
1452	}
1453	if (c == '*') {
1454	    width = va_arg(args, int);
1455	    c = *++fmt;
1456	} else {
1457	    while (isdigit(c)) {
1458		width = width * 10 + c - '0';
1459		c = *++fmt;
1460	    }
1461	}
1462	if (c == '.') {
1463	    c = *++fmt;
1464	    if (c == '*') {
1465		prec = va_arg(args, int);
1466		c = *++fmt;
1467	    } else {
1468		while (isdigit(c)) {
1469		    prec = prec * 10 + c - '0';
1470		    c = *++fmt;
1471		}
1472	    }
1473	}
1474	str = 0;
1475	base = 0;
1476	neg = 0;
1477	++fmt;
1478	switch (c) {
1479	case 'd':
1480	    i = va_arg(args, int);
1481	    if (i < 0) {
1482		neg = 1;
1483		val = -i;
1484	    } else
1485		val = i;
1486	    base = 10;
1487	    break;
1488	case 'o':
1489	    val = va_arg(args, unsigned int);
1490	    base = 8;
1491	    break;
1492	case 'x':
1493	    val = va_arg(args, unsigned int);
1494	    base = 16;
1495	    break;
1496	case 'p':
1497	    val = (unsigned long) va_arg(args, void *);
1498	    base = 16;
1499	    neg = 2;
1500	    break;
1501	case 's':
1502	    str = va_arg(args, char *);
1503	    break;
1504	case 'c':
1505	    num[0] = va_arg(args, int);
1506	    num[1] = 0;
1507	    str = num;
1508	    break;
1509	case 'm':
1510	    str = strerror(errno);
1511	    break;
1512	case 'I':
1513	    str = ip_ntoa(va_arg(args, u_int32_t));
1514	    break;
1515	case 'r':
1516	    f = va_arg(args, char *);
1517#ifndef __powerpc__
1518	    n = vfmtmsg(buf, buflen + 1, f, va_arg(args, va_list));
1519#else
1520	    /* On the powerpc, a va_list is an array of 1 structure */
1521	    n = vfmtmsg(buf, buflen + 1, f, va_arg(args, void *));
1522#endif
1523	    buf += n;
1524	    buflen -= n;
1525	    continue;
1526	case 't':
1527	    time(&t);
1528	    str = ctime(&t);
1529	    str += 4;		/* chop off the day name */
1530	    str[15] = 0;	/* chop off year and newline */
1531	    break;
1532	case 'v':		/* "visible" string */
1533	case 'q':		/* quoted string */
1534	    quoted = c == 'q';
1535	    p = va_arg(args, unsigned char *);
1536	    if (fillch == '0' && prec > 0) {
1537		n = prec;
1538	    } else {
1539		n = strlen((char *)p);
1540		if (prec > 0 && prec < n)
1541		    n = prec;
1542	    }
1543	    while (n > 0 && buflen > 0) {
1544		c = *p++;
1545		--n;
1546		if (!quoted && c >= 0x80) {
1547		    OUTCHAR('M');
1548		    OUTCHAR('-');
1549		    c -= 0x80;
1550		}
1551		if (quoted && (c == '"' || c == '\\'))
1552		    OUTCHAR('\\');
1553		if (c < 0x20 || (0x7f <= c && c < 0xa0)) {
1554		    if (quoted) {
1555			OUTCHAR('\\');
1556			switch (c) {
1557			case '\t':	OUTCHAR('t');	break;
1558			case '\n':	OUTCHAR('n');	break;
1559			case '\b':	OUTCHAR('b');	break;
1560			case '\f':	OUTCHAR('f');	break;
1561			default:
1562			    OUTCHAR('x');
1563			    OUTCHAR(hexchars[c >> 4]);
1564			    OUTCHAR(hexchars[c & 0xf]);
1565			}
1566		    } else {
1567			if (c == '\t')
1568			    OUTCHAR(c);
1569			else {
1570			    OUTCHAR('^');
1571			    OUTCHAR(c ^ 0x40);
1572			}
1573		    }
1574		} else
1575		    OUTCHAR(c);
1576	    }
1577	    continue;
1578	default:
1579	    *buf++ = '%';
1580	    if (c != '%')
1581		--fmt;		/* so %z outputs %z etc. */
1582	    --buflen;
1583	    continue;
1584	}
1585	if (base != 0) {
1586	    str = num + sizeof(num);
1587	    *--str = 0;
1588	    while (str > num + neg) {
1589		*--str = hexchars[val % base];
1590		val = val / base;
1591		if (--prec <= 0 && val == 0)
1592		    break;
1593	    }
1594	    switch (neg) {
1595	    case 1:
1596		*--str = '-';
1597		break;
1598	    case 2:
1599		*--str = 'x';
1600		*--str = '0';
1601		break;
1602	    }
1603	    len = num + sizeof(num) - 1 - str;
1604	} else {
1605	    len = strlen(str);
1606	    if (prec > 0 && len > prec)
1607		len = prec;
1608	}
1609	if (width > 0) {
1610	    if (width > buflen)
1611		width = buflen;
1612	    if ((n = width - len) > 0) {
1613		buflen -= n;
1614		for (; n > 0; --n)
1615		    *buf++ = fillch;
1616	    }
1617	}
1618	if (len > buflen)
1619	    len = buflen;
1620	memcpy(buf, str, len);
1621	buf += len;
1622	buflen -= len;
1623    }
1624    *buf = 0;
1625    return buf - buf0;
1626}
1627
1628/*
1629 * script_setenv - set an environment variable value to be used
1630 * for scripts that we run (e.g. ip-up, auth-up, etc.)
1631 */
1632void
1633script_setenv(var, value)
1634    char *var, *value;
1635{
1636    int vl = strlen(var);
1637    int i;
1638    char *p, *newstring;
1639
1640    newstring = (char *) malloc(vl + strlen(value) + 2);
1641    if (newstring == 0)
1642	novm("script_setenv");
1643    strcpy(newstring, var);
1644    newstring[vl] = '=';
1645    strcpy(newstring+vl+1, value);
1646
1647    /* check if this variable is already set */
1648    if (script_env != 0) {
1649	for (i = 0; (p = script_env[i]) != 0; ++i) {
1650	    if (strncmp(p, var, vl) == 0 && p[vl] == '=') {
1651		free(p);
1652		script_env[i] = newstring;
1653		return;
1654	    }
1655	}
1656    } else {
1657	i = 0;
1658	script_env = (char **) malloc(16 * sizeof(char *));
1659	if (script_env == 0)
1660	    novm("script_setenv");
1661	s_env_nalloc = 16;
1662    }
1663
1664    /* reallocate script_env with more space if needed */
1665    if (i + 1 >= s_env_nalloc) {
1666	int new_n = i + 17;
1667	char **newenv = (char **) realloc((void *)script_env,
1668					  new_n * sizeof(char *));
1669	if (newenv == 0)
1670	    novm("script_setenv");
1671	script_env = newenv;
1672	s_env_nalloc = new_n;
1673    }
1674
1675    script_env[i] = newstring;
1676    script_env[i+1] = 0;
1677}
1678
1679/*
1680 * script_unsetenv - remove a variable from the environment
1681 * for scripts.
1682 */
1683void
1684script_unsetenv(var)
1685    char *var;
1686{
1687    int vl = strlen(var);
1688    int i;
1689    char *p;
1690
1691    if (script_env == 0)
1692	return;
1693    for (i = 0; (p = script_env[i]) != 0; ++i) {
1694	if (strncmp(p, var, vl) == 0 && p[vl] == '=') {
1695	    free(p);
1696	    while ((script_env[i] = script_env[i+1]) != 0)
1697		++i;
1698	    break;
1699	}
1700    }
1701}
1702