1/*
2 * main.c - Point-to-Point Protocol main module
3 *
4 * Copyright (c) 1984-2000 Carnegie Mellon University. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in
15 *    the documentation and/or other materials provided with the
16 *    distribution.
17 *
18 * 3. The name "Carnegie Mellon University" must not be used to
19 *    endorse or promote products derived from this software without
20 *    prior written permission. For permission or any legal
21 *    details, please contact
22 *      Office of Technology Transfer
23 *      Carnegie Mellon University
24 *      5000 Forbes Avenue
25 *      Pittsburgh, PA  15213-3890
26 *      (412) 268-4387, fax: (412) 268-7395
27 *      tech-transfer@andrew.cmu.edu
28 *
29 * 4. Redistributions of any form whatsoever must retain the following
30 *    acknowledgment:
31 *    "This product includes software developed by Computing Services
32 *     at Carnegie Mellon University (http://www.cmu.edu/computing/)."
33 *
34 * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
35 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
36 * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
37 * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
38 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
39 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
40 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
41 *
42 * Copyright (c) 1999-2004 Paul Mackerras. All rights reserved.
43 *
44 * Redistribution and use in source and binary forms, with or without
45 * modification, are permitted provided that the following conditions
46 * are met:
47 *
48 * 1. Redistributions of source code must retain the above copyright
49 *    notice, this list of conditions and the following disclaimer.
50 *
51 * 2. The name(s) of the authors of this software must not be used to
52 *    endorse or promote products derived from this software without
53 *    prior written permission.
54 *
55 * 3. Redistributions of any form whatsoever must retain the following
56 *    acknowledgment:
57 *    "This product includes software developed by Paul Mackerras
58 *     <paulus@samba.org>".
59 *
60 * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
61 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
62 * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
63 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
64 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
65 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
66 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
67 */
68
69#define RCSID	"$Id: main.c,v 1.148 2004/11/13 12:05:48 paulus Exp $"
70
71#include <stdio.h>
72#include <ctype.h>
73#include <stdlib.h>
74#include <string.h>
75#include <unistd.h>
76#include <signal.h>
77#include <errno.h>
78#include <fcntl.h>
79#include <syslog.h>
80#include <netdb.h>
81#include <utmp.h>
82#include <pwd.h>
83#include <setjmp.h>
84#include <sys/param.h>
85#include <sys/types.h>
86#include <sys/wait.h>
87#include <sys/time.h>
88#include <sys/resource.h>
89#include <sys/stat.h>
90#include <sys/socket.h>
91#include <netinet/in.h>
92#include <arpa/inet.h>
93#include <cutils/properties.h>
94
95#include "pppd.h"
96#include "magic.h"
97#include "fsm.h"
98#include "lcp.h"
99#include "ipcp.h"
100#ifdef INET6
101#include "ipv6cp.h"
102#endif
103#include "upap.h"
104#include "chap-new.h"
105#include "eap.h"
106#include "ccp.h"
107#include "ecp.h"
108#include "pathnames.h"
109
110#ifdef USE_TDB
111#include "tdb.h"
112#endif
113
114#ifdef CBCP_SUPPORT
115#include "cbcp.h"
116#endif
117
118#ifdef IPX_CHANGE
119#include "ipxcp.h"
120#endif /* IPX_CHANGE */
121#ifdef AT_CHANGE
122#include "atcp.h"
123#endif
124
125static const char rcsid[] = RCSID;
126
127/* interface vars */
128char ifname[32];		/* Interface name */
129int ifunit;			/* Interface unit number */
130
131struct channel *the_channel;
132
133char *progname;			/* Name of this program */
134char hostname[MAXNAMELEN];	/* Our hostname */
135static char pidfilename[MAXPATHLEN];	/* name of pid file */
136static char linkpidfile[MAXPATHLEN];	/* name of linkname pid file */
137char ppp_devnam[MAXPATHLEN];	/* name of PPP tty (maybe ttypx) */
138uid_t uid;			/* Our real user-id */
139struct notifier *pidchange = NULL;
140struct notifier *phasechange = NULL;
141struct notifier *exitnotify = NULL;
142struct notifier *sigreceived = NULL;
143struct notifier *fork_notifier = NULL;
144
145int hungup;			/* terminal has been hung up */
146int privileged;			/* we're running as real uid root */
147int need_holdoff;		/* need holdoff period before restarting */
148int detached;			/* have detached from terminal */
149volatile int status;		/* exit status for pppd */
150int unsuccess;			/* # unsuccessful connection attempts */
151int do_callback;		/* != 0 if we should do callback next */
152int doing_callback;		/* != 0 if we are doing callback */
153int ppp_session_number;		/* Session number, for channels with such a
154				   concept (eg PPPoE) */
155int childwait_done;		/* have timed out waiting for children */
156
157#ifdef USE_TDB
158TDB_CONTEXT *pppdb;		/* database for storing status etc. */
159#endif
160
161char db_key[32];
162
163int (*holdoff_hook) __P((void)) = NULL;
164int (*new_phase_hook) __P((int)) = NULL;
165void (*snoop_recv_hook) __P((unsigned char *p, int len)) = NULL;
166void (*snoop_send_hook) __P((unsigned char *p, int len)) = NULL;
167
168static int conn_running;	/* we have a [dis]connector running */
169static int fd_loop;		/* fd for getting demand-dial packets */
170
171int fd_devnull;			/* fd for /dev/null */
172int devfd = -1;			/* fd of underlying device */
173int fd_ppp = -1;		/* fd for talking PPP */
174int phase;			/* where the link is at */
175int kill_link;
176int asked_to_quit;
177int open_ccp_flag;
178int listen_time;
179int got_sigusr2;
180int got_sigterm;
181int got_sighup;
182
183static sigset_t signals_handled;
184static int waiting;
185static sigjmp_buf sigjmp;
186
187char **script_env;		/* Env. variable values for scripts */
188int s_env_nalloc;		/* # words avail at script_env */
189
190u_char outpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for outgoing packet */
191u_char inpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for incoming packet */
192
193static int n_children;		/* # child processes still running */
194static int got_sigchld;		/* set if we have received a SIGCHLD */
195
196int privopen;			/* don't lock, open device as root */
197
198char *no_ppp_msg = "Sorry - this system lacks PPP kernel support\n";
199
200GIDSET_TYPE groups[NGROUPS_MAX];/* groups the user is in */
201int ngroups;			/* How many groups valid in groups */
202
203static struct timeval start_time;	/* Time when link was started. */
204
205static struct pppd_stats old_link_stats;
206struct pppd_stats link_stats;
207unsigned link_connect_time;
208int link_stats_valid;
209
210int error_count;
211
212bool bundle_eof;
213bool bundle_terminating;
214
215int sent_since_received = 0;
216int sent_total = 0;
217int received_total = 0;
218
219/*
220 * We maintain a list of child process pids and
221 * functions to call when they exit.
222 */
223struct subprocess {
224    pid_t	pid;
225    char	*prog;
226    void	(*done) __P((void *));
227    void	*arg;
228    struct subprocess *next;
229};
230
231static struct subprocess *children;
232
233/* Prototypes for procedures local to this file. */
234
235static void setup_signals __P((void));
236static void create_pidfile __P((int pid));
237static void create_linkpidfile __P((int pid));
238static void cleanup __P((void));
239static void get_input __P((void));
240static void calltimeout __P((void));
241static struct timeval *timeleft __P((struct timeval *));
242static void kill_my_pg __P((int));
243static void hup __P((int));
244static void term __P((int));
245static void chld __P((int));
246static void toggle_debug __P((int));
247static void open_ccp __P((int));
248static void bad_signal __P((int));
249static void holdoff_end __P((void *));
250static int reap_kids __P((void));
251static void childwait_end __P((void *));
252
253#ifdef USE_TDB
254static void update_db_entry __P((void));
255static void add_db_key __P((const char *));
256static void delete_db_key __P((const char *));
257static void cleanup_db __P((void));
258#endif
259
260static void handle_events __P((void));
261void print_link_stats __P((void));
262
263extern	char	*ttyname __P((int));
264extern	char	*getlogin __P((void));
265int main __P((int, char *[]));
266
267#ifdef ultrix
268#undef	O_NONBLOCK
269#define	O_NONBLOCK	O_NDELAY
270#endif
271
272#ifdef ULTRIX
273#define setlogmask(x)
274#endif
275
276/*
277 * PPP Data Link Layer "protocol" table.
278 * One entry per supported protocol.
279 * The last entry must be NULL.
280 */
281struct protent *protocols[] = {
282    &lcp_protent,
283    &pap_protent,
284    &chap_protent,
285#ifdef CBCP_SUPPORT
286    &cbcp_protent,
287#endif
288    &ipcp_protent,
289#ifdef INET6
290    &ipv6cp_protent,
291#endif
292    &ccp_protent,
293    &ecp_protent,
294#ifdef IPX_CHANGE
295    &ipxcp_protent,
296#endif
297#ifdef AT_CHANGE
298    &atcp_protent,
299#endif
300    &eap_protent,
301    NULL
302};
303
304/*
305 * If PPP_DRV_NAME is not defined, use the default "ppp" as the device name.
306 */
307#if !defined(PPP_DRV_NAME)
308#define PPP_DRV_NAME	"ppp"
309#endif /* !defined(PPP_DRV_NAME) */
310
311int
312main(argc, argv)
313    int argc;
314    char *argv[];
315{
316    int i, t;
317    char *p;
318    struct passwd *pw;
319    struct protent *protp;
320    char numbuf[16];
321
322    link_stats_valid = 0;
323    new_phase(PHASE_INITIALIZE);
324
325    script_env = NULL;
326
327    /* Initialize syslog facilities */
328    reopen_log();
329
330    if (gethostname(hostname, MAXNAMELEN) < 0 ) {
331	option_error("Couldn't get hostname: %m");
332	exit(1);
333    }
334    hostname[MAXNAMELEN-1] = 0;
335
336    /* make sure we don't create world or group writable files. */
337    umask(umask(0777) | 022);
338
339    uid = getuid();
340    privileged = uid == 0;
341    slprintf(numbuf, sizeof(numbuf), "%d", uid);
342    script_setenv("ORIG_UID", numbuf, 0);
343
344    ngroups = getgroups(NGROUPS_MAX, groups);
345
346    /*
347     * Initialize magic number generator now so that protocols may
348     * use magic numbers in initialization.
349     */
350    magic_init();
351
352    /*
353     * Initialize each protocol.
354     */
355    for (i = 0; (protp = protocols[i]) != NULL; ++i)
356        (*protp->init)(0);
357
358    /*
359     * Initialize the default channel.
360     */
361    tty_init();
362
363    progname = *argv;
364
365#ifdef ANDROID_CHANGES
366    {
367        extern void pppox_init();
368        pppox_init();
369        privileged = 1;
370    }
371    {
372        char *envargs = getenv("envargs");
373        if (envargs) {
374            int i;
375            /* Decode the arguments in-place and count the number of them.
376             * They were hex encoded using [A-P] instead of [0-9A-F]. */
377            for (argc = 0, i = 0; envargs[i] && envargs[i + 1]; i += 2) {
378                char c = ((envargs[i] - 'A') << 4) + (envargs[i + 1] - 'A');
379                if (c == 0) {
380                    ++argc;
381                }
382                envargs[i / 2 + 1] = c;
383            }
384            if (argc == 0 || (argv = malloc(sizeof(char *) * argc)) == NULL) {
385                fatal("Failed to parse envargs!");
386            }
387            for (envargs[0] = 0, i = 0; i < argc; ++envargs) {
388                if (envargs[0] == 0) {
389                    argv[i++] = &envargs[1];
390                }
391            }
392        }
393    }
394#endif
395
396    /*
397     * Parse, in order, the system options file, the user's options file,
398     * and the command line arguments.
399     */
400#ifdef ANDROID_CHANGES
401    /* Android: only take options from commandline */
402    if (!parse_args(argc-1, argv+1))
403	exit(EXIT_OPTION_ERROR);
404
405#else
406    if (!options_from_file(_PATH_SYSOPTIONS, !privileged, 0, 1)
407	|| !options_from_user()
408	|| !parse_args(argc-1, argv+1))
409	exit(EXIT_OPTION_ERROR);
410
411#endif
412
413    devnam_fixed = 1;		/* can no longer change device name */
414
415    /*
416     * Work out the device name, if it hasn't already been specified,
417     * and parse the tty's options file.
418     */
419    if (the_channel->process_extra_options)
420	(*the_channel->process_extra_options)();
421
422    if (debug)
423	setlogmask(LOG_UPTO(LOG_DEBUG));
424
425#ifndef ANDROID_CHANGES
426    /*
427     * Check that we are running as root.
428     */
429    if (geteuid() != 0) {
430	option_error("must be root to run %s, since it is not setuid-root",
431		     argv[0]);
432	exit(EXIT_NOT_ROOT);
433    }
434#endif
435
436    if (!ppp_available()) {
437	option_error("%s", no_ppp_msg);
438	exit(EXIT_NO_KERNEL_SUPPORT);
439    }
440
441    /*
442     * Check that the options given are valid and consistent.
443     */
444    check_options();
445    if (!sys_check_options())
446	exit(EXIT_OPTION_ERROR);
447    auth_check_options();
448#ifdef HAVE_MULTILINK
449    mp_check_options();
450#endif
451    for (i = 0; (protp = protocols[i]) != NULL; ++i)
452	if (protp->check_options != NULL)
453	    (*protp->check_options)();
454    if (the_channel->check_options)
455	(*the_channel->check_options)();
456
457
458    if (dump_options || dryrun) {
459	init_pr_log(NULL, LOG_INFO);
460	print_options(pr_log, NULL);
461	end_pr_log();
462    }
463
464    if (dryrun)
465	die(0);
466
467    /* Make sure fds 0, 1, 2 are open to somewhere. */
468    fd_devnull = open(_PATH_DEVNULL, O_RDWR);
469    if (fd_devnull < 0)
470	fatal("Couldn't open %s: %m", _PATH_DEVNULL);
471    while (fd_devnull <= 2) {
472	i = dup(fd_devnull);
473	if (i < 0)
474	    fatal("Critical shortage of file descriptors: dup failed: %m");
475	fd_devnull = i;
476    }
477
478    /*
479     * Initialize system-dependent stuff.
480     */
481    sys_init();
482#ifdef USE_TDB
483    pppdb = tdb_open(_PATH_PPPDB, 0, 0, O_RDWR|O_CREAT, 0644);
484    if (pppdb != NULL) {
485	slprintf(db_key, sizeof(db_key), "pppd%d", getpid());
486	update_db_entry();
487    } else {
488	warn("Warning: couldn't open ppp database %s", _PATH_PPPDB);
489	if (multilink) {
490	    warn("Warning: disabling multilink");
491	    multilink = 0;
492	}
493    }
494#endif
495
496    /*
497     * Detach ourselves from the terminal, if required,
498     * and identify who is running us.
499     */
500    if (!nodetach && !updetach)
501	detach();
502    p = getlogin();
503    if (p == NULL) {
504	pw = getpwuid(uid);
505	if (pw != NULL && pw->pw_name != NULL)
506	    p = pw->pw_name;
507	else
508	    p = "(unknown)";
509    }
510    syslog(LOG_NOTICE, "pppd %s started by %s, uid %d", VERSION, p, uid);
511    script_setenv("PPPLOGNAME", p, 0);
512
513    if (devnam[0])
514	script_setenv("DEVICE", devnam, 1);
515    slprintf(numbuf, sizeof(numbuf), "%d", getpid());
516    script_setenv("PPPD_PID", numbuf, 1);
517
518    setup_signals();
519
520    create_linkpidfile(getpid());
521
522    waiting = 0;
523
524    /*
525     * If we're doing dial-on-demand, set up the interface now.
526     */
527    if (demand) {
528	/*
529	 * Open the loopback channel and set it up to be the ppp interface.
530	 */
531	fd_loop = open_ppp_loopback();
532	set_ifunit(1);
533	/*
534	 * Configure the interface and mark it up, etc.
535	 */
536	demand_conf();
537    }
538
539    do_callback = 0;
540    for (;;) {
541
542	bundle_eof = 0;
543	bundle_terminating = 0;
544	listen_time = 0;
545	need_holdoff = 1;
546	devfd = -1;
547	status = EXIT_OK;
548	++unsuccess;
549	doing_callback = do_callback;
550	do_callback = 0;
551
552	if (demand && !doing_callback) {
553	    /*
554	     * Don't do anything until we see some activity.
555	     */
556	    new_phase(PHASE_DORMANT);
557	    demand_unblock();
558	    add_fd(fd_loop);
559	    for (;;) {
560		handle_events();
561		if (asked_to_quit)
562		    break;
563		if (get_loop_output())
564		    break;
565	    }
566	    remove_fd(fd_loop);
567	    if (asked_to_quit)
568		break;
569
570	    /*
571	     * Now we want to bring up the link.
572	     */
573	    demand_block();
574	    info("Starting link");
575	}
576
577	gettimeofday(&start_time, NULL);
578	script_unsetenv("CONNECT_TIME");
579	script_unsetenv("BYTES_SENT");
580	script_unsetenv("BYTES_RCVD");
581
582	lcp_open(0);		/* Start protocol */
583	while (phase != PHASE_DEAD) {
584	    handle_events();
585	    get_input();
586	    if (kill_link)
587		lcp_close(0, "User request");
588	    if (asked_to_quit) {
589		bundle_terminating = 1;
590		if (phase == PHASE_MASTER)
591		    mp_bundle_terminated();
592	    }
593	    if (open_ccp_flag) {
594		if (phase == PHASE_NETWORK || phase == PHASE_RUNNING) {
595		    ccp_fsm[0].flags = OPT_RESTART; /* clears OPT_SILENT */
596		    (*ccp_protent.open)(0);
597		}
598	    }
599	}
600
601	if (!persist || asked_to_quit || (maxfail > 0 && unsuccess >= maxfail))
602	    break;
603
604	if (demand)
605	    demand_discard();
606	t = need_holdoff? holdoff: 0;
607	if (holdoff_hook)
608	    t = (*holdoff_hook)();
609	if (t > 0) {
610	    new_phase(PHASE_HOLDOFF);
611	    TIMEOUT(holdoff_end, NULL, t);
612	    do {
613		handle_events();
614		if (kill_link)
615		    new_phase(PHASE_DORMANT); /* allow signal to end holdoff */
616	    } while (phase == PHASE_HOLDOFF);
617	    if (!persist)
618		break;
619	}
620    }
621
622    /* Wait for scripts to finish */
623    reap_kids();
624    if (n_children > 0) {
625	if (child_wait > 0)
626	    TIMEOUT(childwait_end, NULL, child_wait);
627	if (debug) {
628	    struct subprocess *chp;
629	    dbglog("Waiting for %d child processes...", n_children);
630	    for (chp = children; chp != NULL; chp = chp->next)
631		dbglog("  script %s, pid %d", chp->prog, chp->pid);
632	}
633	while (n_children > 0 && !childwait_done) {
634	    handle_events();
635	    if (kill_link && !childwait_done)
636		childwait_end(NULL);
637	}
638    }
639
640    die(status);
641    return 0;
642}
643
644/*
645 * handle_events - wait for something to happen and respond to it.
646 */
647static void
648handle_events()
649{
650    struct timeval timo;
651
652    kill_link = open_ccp_flag = 0;
653    if (sigsetjmp(sigjmp, 1) == 0) {
654	sigprocmask(SIG_BLOCK, &signals_handled, NULL);
655	if (got_sighup || got_sigterm || got_sigusr2 || got_sigchld) {
656	    sigprocmask(SIG_UNBLOCK, &signals_handled, NULL);
657	} else {
658	    waiting = 1;
659	    sigprocmask(SIG_UNBLOCK, &signals_handled, NULL);
660	    wait_input(timeleft(&timo));
661	}
662    }
663    waiting = 0;
664    calltimeout();
665    if (got_sighup) {
666	info("Hangup (SIGHUP)");
667	kill_link = 1;
668	got_sighup = 0;
669	if (status != EXIT_HANGUP)
670	    status = EXIT_USER_REQUEST;
671    }
672    if (got_sigterm) {
673	info("Terminating on signal %d", got_sigterm);
674	kill_link = 1;
675	asked_to_quit = 1;
676	persist = 0;
677	status = EXIT_USER_REQUEST;
678	got_sigterm = 0;
679    }
680    if (got_sigchld) {
681	got_sigchld = 0;
682	reap_kids();	/* Don't leave dead kids lying around */
683    }
684    if (got_sigusr2) {
685	open_ccp_flag = 1;
686	got_sigusr2 = 0;
687    }
688}
689
690/*
691 * setup_signals - initialize signal handling.
692 */
693static void
694setup_signals()
695{
696    struct sigaction sa;
697
698    /*
699     * Compute mask of all interesting signals and install signal handlers
700     * for each.  Only one signal handler may be active at a time.  Therefore,
701     * all other signals should be masked when any handler is executing.
702     */
703    sigemptyset(&signals_handled);
704    sigaddset(&signals_handled, SIGHUP);
705    sigaddset(&signals_handled, SIGINT);
706    sigaddset(&signals_handled, SIGTERM);
707    sigaddset(&signals_handled, SIGCHLD);
708    sigaddset(&signals_handled, SIGUSR2);
709
710#define SIGNAL(s, handler)	do { \
711	sa.sa_handler = handler; \
712	if (sigaction(s, &sa, NULL) < 0) \
713	    fatal("Couldn't establish signal handler (%d): %m", s); \
714    } while (0)
715
716    sa.sa_mask = signals_handled;
717    sa.sa_flags = 0;
718    SIGNAL(SIGHUP, hup);		/* Hangup */
719    SIGNAL(SIGINT, term);		/* Interrupt */
720    SIGNAL(SIGTERM, term);		/* Terminate */
721    SIGNAL(SIGCHLD, chld);
722
723    SIGNAL(SIGUSR1, toggle_debug);	/* Toggle debug flag */
724    SIGNAL(SIGUSR2, open_ccp);		/* Reopen CCP */
725
726    /*
727     * Install a handler for other signals which would otherwise
728     * cause pppd to exit without cleaning up.
729     */
730    SIGNAL(SIGABRT, bad_signal);
731    SIGNAL(SIGALRM, bad_signal);
732    SIGNAL(SIGFPE, bad_signal);
733    SIGNAL(SIGILL, bad_signal);
734    SIGNAL(SIGPIPE, bad_signal);
735    SIGNAL(SIGQUIT, bad_signal);
736    SIGNAL(SIGSEGV, bad_signal);
737#ifdef SIGBUS
738    SIGNAL(SIGBUS, bad_signal);
739#endif
740#ifdef SIGEMT
741    SIGNAL(SIGEMT, bad_signal);
742#endif
743#ifdef SIGPOLL
744    SIGNAL(SIGPOLL, bad_signal);
745#endif
746#ifdef SIGPROF
747    SIGNAL(SIGPROF, bad_signal);
748#endif
749#ifdef SIGSYS
750    SIGNAL(SIGSYS, bad_signal);
751#endif
752#ifdef SIGTRAP
753    SIGNAL(SIGTRAP, bad_signal);
754#endif
755#ifdef SIGVTALRM
756    SIGNAL(SIGVTALRM, bad_signal);
757#endif
758#ifdef SIGXCPU
759    SIGNAL(SIGXCPU, bad_signal);
760#endif
761#ifdef SIGXFSZ
762    SIGNAL(SIGXFSZ, bad_signal);
763#endif
764
765    /*
766     * Apparently we can get a SIGPIPE when we call syslog, if
767     * syslogd has died and been restarted.  Ignoring it seems
768     * be sufficient.
769     */
770    signal(SIGPIPE, SIG_IGN);
771}
772
773/*
774 * set_ifunit - do things we need to do once we know which ppp
775 * unit we are using.
776 */
777void
778set_ifunit(iskey)
779    int iskey;
780{
781    info("Using interface %s%d", PPP_DRV_NAME, ifunit);
782    slprintf(ifname, sizeof(ifname), "%s%d", PPP_DRV_NAME, ifunit);
783    script_setenv("IFNAME", ifname, iskey);
784    if (iskey) {
785	create_pidfile(getpid());	/* write pid to file */
786	create_linkpidfile(getpid());
787    }
788}
789
790/*
791 * detach - detach us from the controlling terminal.
792 */
793void
794detach()
795{
796    int pid;
797    char numbuf[16];
798    int pipefd[2];
799
800    if (detached)
801	return;
802    if (pipe(pipefd) == -1)
803	pipefd[0] = pipefd[1] = -1;
804    if ((pid = fork()) < 0) {
805	error("Couldn't detach (fork failed: %m)");
806	die(1);			/* or just return? */
807    }
808    if (pid != 0) {
809	/* parent */
810	notify(pidchange, pid);
811	/* update pid files if they have been written already */
812	if (pidfilename[0])
813	    create_pidfile(pid);
814	if (linkpidfile[0])
815	    create_linkpidfile(pid);
816	exit(0);		/* parent dies */
817    }
818    setsid();
819    chdir("/");
820    dup2(fd_devnull, 0);
821    dup2(fd_devnull, 1);
822    dup2(fd_devnull, 2);
823    detached = 1;
824    if (log_default)
825	log_to_fd = -1;
826    slprintf(numbuf, sizeof(numbuf), "%d", getpid());
827    script_setenv("PPPD_PID", numbuf, 1);
828
829    /* wait for parent to finish updating pid & lock files and die */
830    close(pipefd[1]);
831    complete_read(pipefd[0], numbuf, 1);
832    close(pipefd[0]);
833}
834
835/*
836 * reopen_log - (re)open our connection to syslog.
837 */
838void
839reopen_log()
840{
841#ifndef ANDROID_CHANGES
842    openlog("pppd", LOG_PID | LOG_NDELAY, LOG_PPP);
843    setlogmask(LOG_UPTO(LOG_INFO));
844#endif
845}
846
847/*
848 * Create a file containing our process ID.
849 */
850static void
851create_pidfile(pid)
852    int pid;
853{
854#ifndef ANDROID_CHANGES
855    FILE *pidfile;
856
857    slprintf(pidfilename, sizeof(pidfilename), "%s%s.pid",
858	     _PATH_VARRUN, ifname);
859    if ((pidfile = fopen(pidfilename, "w")) != NULL) {
860	fprintf(pidfile, "%d\n", pid);
861	(void) fclose(pidfile);
862    } else {
863	error("Failed to create pid file %s: %m", pidfilename);
864	pidfilename[0] = 0;
865    }
866#endif
867}
868
869void
870create_linkpidfile(pid)
871    int pid;
872{
873#ifndef ANDROID_CHANGES
874    FILE *pidfile;
875
876    if (linkname[0] == 0)
877	return;
878    script_setenv("LINKNAME", linkname, 1);
879    slprintf(linkpidfile, sizeof(linkpidfile), "%sppp-%s.pid",
880	     _PATH_VARRUN, linkname);
881    if ((pidfile = fopen(linkpidfile, "w")) != NULL) {
882	fprintf(pidfile, "%d\n", pid);
883	if (ifname[0])
884	    fprintf(pidfile, "%s\n", ifname);
885	(void) fclose(pidfile);
886    } else {
887	error("Failed to create pid file %s: %m", linkpidfile);
888	linkpidfile[0] = 0;
889    }
890#endif
891}
892
893/*
894 * remove_pidfile - remove our pid files
895 */
896void remove_pidfiles()
897{
898#ifndef ANDROID_CHANGES
899    if (pidfilename[0] != 0 && unlink(pidfilename) < 0 && errno != ENOENT)
900	warn("unable to delete pid file %s: %m", pidfilename);
901    pidfilename[0] = 0;
902    if (linkpidfile[0] != 0 && unlink(linkpidfile) < 0 && errno != ENOENT)
903	warn("unable to delete pid file %s: %m", linkpidfile);
904    linkpidfile[0] = 0;
905#endif
906}
907
908/*
909 * holdoff_end - called via a timeout when the holdoff period ends.
910 */
911static void
912holdoff_end(arg)
913    void *arg;
914{
915    new_phase(PHASE_DORMANT);
916}
917
918/* List of protocol names, to make our messages a little more informative. */
919struct protocol_list {
920    u_short	proto;
921    const char	*name;
922} protocol_list[] = {
923    { 0x21,	"IP" },
924    { 0x23,	"OSI Network Layer" },
925    { 0x25,	"Xerox NS IDP" },
926    { 0x27,	"DECnet Phase IV" },
927    { 0x29,	"Appletalk" },
928    { 0x2b,	"Novell IPX" },
929    { 0x2d,	"VJ compressed TCP/IP" },
930    { 0x2f,	"VJ uncompressed TCP/IP" },
931    { 0x31,	"Bridging PDU" },
932    { 0x33,	"Stream Protocol ST-II" },
933    { 0x35,	"Banyan Vines" },
934    { 0x39,	"AppleTalk EDDP" },
935    { 0x3b,	"AppleTalk SmartBuffered" },
936    { 0x3d,	"Multi-Link" },
937    { 0x3f,	"NETBIOS Framing" },
938    { 0x41,	"Cisco Systems" },
939    { 0x43,	"Ascom Timeplex" },
940    { 0x45,	"Fujitsu Link Backup and Load Balancing (LBLB)" },
941    { 0x47,	"DCA Remote Lan" },
942    { 0x49,	"Serial Data Transport Protocol (PPP-SDTP)" },
943    { 0x4b,	"SNA over 802.2" },
944    { 0x4d,	"SNA" },
945    { 0x4f,	"IP6 Header Compression" },
946    { 0x6f,	"Stampede Bridging" },
947    { 0xfb,	"single-link compression" },
948    { 0xfd,	"1st choice compression" },
949    { 0x0201,	"802.1d Hello Packets" },
950    { 0x0203,	"IBM Source Routing BPDU" },
951    { 0x0205,	"DEC LANBridge100 Spanning Tree" },
952    { 0x0231,	"Luxcom" },
953    { 0x0233,	"Sigma Network Systems" },
954    { 0x8021,	"Internet Protocol Control Protocol" },
955    { 0x8023,	"OSI Network Layer Control Protocol" },
956    { 0x8025,	"Xerox NS IDP Control Protocol" },
957    { 0x8027,	"DECnet Phase IV Control Protocol" },
958    { 0x8029,	"Appletalk Control Protocol" },
959    { 0x802b,	"Novell IPX Control Protocol" },
960    { 0x8031,	"Bridging NCP" },
961    { 0x8033,	"Stream Protocol Control Protocol" },
962    { 0x8035,	"Banyan Vines Control Protocol" },
963    { 0x803d,	"Multi-Link Control Protocol" },
964    { 0x803f,	"NETBIOS Framing Control Protocol" },
965    { 0x8041,	"Cisco Systems Control Protocol" },
966    { 0x8043,	"Ascom Timeplex" },
967    { 0x8045,	"Fujitsu LBLB Control Protocol" },
968    { 0x8047,	"DCA Remote Lan Network Control Protocol (RLNCP)" },
969    { 0x8049,	"Serial Data Control Protocol (PPP-SDCP)" },
970    { 0x804b,	"SNA over 802.2 Control Protocol" },
971    { 0x804d,	"SNA Control Protocol" },
972    { 0x804f,	"IP6 Header Compression Control Protocol" },
973    { 0x006f,	"Stampede Bridging Control Protocol" },
974    { 0x80fb,	"Single Link Compression Control Protocol" },
975    { 0x80fd,	"Compression Control Protocol" },
976    { 0xc021,	"Link Control Protocol" },
977    { 0xc023,	"Password Authentication Protocol" },
978    { 0xc025,	"Link Quality Report" },
979    { 0xc027,	"Shiva Password Authentication Protocol" },
980    { 0xc029,	"CallBack Control Protocol (CBCP)" },
981    { 0xc081,	"Container Control Protocol" },
982    { 0xc223,	"Challenge Handshake Authentication Protocol" },
983    { 0xc281,	"Proprietary Authentication Protocol" },
984    { 0,	NULL },
985};
986
987/*
988 * protocol_name - find a name for a PPP protocol.
989 */
990const char *
991protocol_name(proto)
992    int proto;
993{
994    struct protocol_list *lp;
995
996    for (lp = protocol_list; lp->proto != 0; ++lp)
997	if (proto == lp->proto)
998	    return lp->name;
999    return NULL;
1000}
1001
1002/*
1003 * get_input - called when incoming data is available.
1004 */
1005static void
1006get_input()
1007{
1008    int len, i;
1009    u_char *p;
1010    u_short protocol;
1011    struct protent *protp;
1012
1013    p = inpacket_buf;	/* point to beginning of packet buffer */
1014
1015    len = read_packet(inpacket_buf);
1016    if (len < 0)
1017	return;
1018
1019    if (len == 0) {
1020	if (bundle_eof && multilink_master) {
1021	    notice("Last channel has disconnected");
1022	    mp_bundle_terminated();
1023	    return;
1024	}
1025	notice("Modem hangup");
1026	hungup = 1;
1027	status = EXIT_HANGUP;
1028	lcp_lowerdown(0);	/* serial link is no longer available */
1029	link_terminated(0);
1030	return;
1031    }
1032
1033    if (len < PPP_HDRLEN) {
1034	dbglog("received short packet:%.*B", len, p);
1035	return;
1036    }
1037
1038    dump_packet("rcvd", p, len);
1039    if (snoop_recv_hook) snoop_recv_hook(p, len);
1040
1041    p += 2;				/* Skip address and control */
1042    GETSHORT(protocol, p);
1043    len -= PPP_HDRLEN;
1044
1045    /*
1046     * Toss all non-LCP packets unless LCP is OPEN.
1047     */
1048    if (protocol != PPP_LCP && lcp_fsm[0].state != OPENED) {
1049	dbglog("Discarded non-LCP packet when LCP not open");
1050	return;
1051    }
1052
1053    /*
1054     * Until we get past the authentication phase, toss all packets
1055     * except LCP, LQR and authentication packets.
1056     */
1057    if (phase <= PHASE_AUTHENTICATE
1058	&& !(protocol == PPP_LCP || protocol == PPP_LQR
1059	     || protocol == PPP_PAP || protocol == PPP_CHAP ||
1060		protocol == PPP_EAP)) {
1061	dbglog("discarding proto 0x%x in phase %d",
1062		   protocol, phase);
1063	return;
1064    }
1065
1066    /*
1067     * Upcall the proper protocol input routine.
1068     */
1069    for (i = 0; (protp = protocols[i]) != NULL; ++i) {
1070	if (protp->protocol == protocol && protp->enabled_flag) {
1071	    (*protp->input)(0, p, len);
1072	    return;
1073	}
1074        if (protocol == (protp->protocol & ~0x8000) && protp->enabled_flag
1075	    && protp->datainput != NULL) {
1076	    (*protp->datainput)(0, p, len);
1077	    return;
1078	}
1079    }
1080
1081    if (debug) {
1082	const char *pname = protocol_name(protocol);
1083	if (pname != NULL)
1084	    warn("Unsupported protocol '%s' (0x%x) received", pname, protocol);
1085	else
1086	    warn("Unsupported protocol 0x%x received", protocol);
1087    }
1088    lcp_sprotrej(0, p - PPP_HDRLEN, len + PPP_HDRLEN);
1089}
1090
1091/*
1092 * ppp_send_config - configure the transmit-side characteristics of
1093 * the ppp interface.  Returns -1, indicating an error, if the channel
1094 * send_config procedure called error() (or incremented error_count
1095 * itself), otherwise 0.
1096 */
1097int
1098ppp_send_config(unit, mtu, accm, pcomp, accomp)
1099    int unit, mtu;
1100    u_int32_t accm;
1101    int pcomp, accomp;
1102{
1103	int errs;
1104
1105	if (the_channel->send_config == NULL)
1106		return 0;
1107	errs = error_count;
1108	(*the_channel->send_config)(mtu, accm, pcomp, accomp);
1109	return (error_count != errs)? -1: 0;
1110}
1111
1112/*
1113 * ppp_recv_config - configure the receive-side characteristics of
1114 * the ppp interface.  Returns -1, indicating an error, if the channel
1115 * recv_config procedure called error() (or incremented error_count
1116 * itself), otherwise 0.
1117 */
1118int
1119ppp_recv_config(unit, mru, accm, pcomp, accomp)
1120    int unit, mru;
1121    u_int32_t accm;
1122    int pcomp, accomp;
1123{
1124	int errs;
1125
1126	if (the_channel->recv_config == NULL)
1127		return 0;
1128	errs = error_count;
1129	(*the_channel->recv_config)(mru, accm, pcomp, accomp);
1130	return (error_count != errs)? -1: 0;
1131}
1132
1133/*
1134 * new_phase - signal the start of a new phase of pppd's operation.
1135 */
1136void
1137new_phase(p)
1138    int p;
1139{
1140    phase = p;
1141    if (new_phase_hook)
1142	(*new_phase_hook)(p);
1143    notify(phasechange, p);
1144}
1145
1146/*
1147 * die - clean up state and exit with the specified status.
1148 */
1149void
1150die(status)
1151    int status;
1152{
1153    if (!doing_multilink || multilink_master)
1154	print_link_stats();
1155    cleanup();
1156    notify(exitnotify, status);
1157    syslog(LOG_INFO, "Exit.");
1158    exit(status);
1159}
1160
1161/*
1162 * cleanup - restore anything which needs to be restored before we exit
1163 */
1164/* ARGSUSED */
1165static void
1166cleanup()
1167{
1168    sys_cleanup();
1169
1170    if (fd_ppp >= 0)
1171	the_channel->disestablish_ppp(devfd);
1172    if (the_channel->cleanup)
1173	(*the_channel->cleanup)();
1174    remove_pidfiles();
1175
1176#ifdef USE_TDB
1177    if (pppdb != NULL)
1178	cleanup_db();
1179#endif
1180
1181}
1182
1183void
1184print_link_stats()
1185{
1186    /*
1187     * Print connect time and statistics.
1188     */
1189    if (link_stats_valid) {
1190       int t = (link_connect_time + 5) / 6;    /* 1/10ths of minutes */
1191       info("Connect time %d.%d minutes.", t/10, t%10);
1192       info("Sent %u bytes, received %u bytes.",
1193	    link_stats.bytes_out, link_stats.bytes_in);
1194       link_stats_valid = 0;
1195    }
1196}
1197
1198/*
1199 * reset_link_stats - "reset" stats when link goes up.
1200 */
1201void
1202reset_link_stats(u)
1203    int u;
1204{
1205    if (!get_ppp_stats(u, &old_link_stats))
1206	return;
1207    gettimeofday(&start_time, NULL);
1208}
1209
1210/*
1211 * update_link_stats - get stats at link termination.
1212 */
1213void
1214update_link_stats(u)
1215    int u;
1216{
1217    struct timeval now;
1218    char numbuf[32];
1219
1220    if (!get_ppp_stats(u, &link_stats)
1221	|| gettimeofday(&now, NULL) < 0)
1222	return;
1223    link_connect_time = now.tv_sec - start_time.tv_sec;
1224    link_stats_valid = 1;
1225
1226    link_stats.bytes_in  -= old_link_stats.bytes_in;
1227    link_stats.bytes_out -= old_link_stats.bytes_out;
1228    link_stats.pkts_in   -= old_link_stats.pkts_in;
1229    link_stats.pkts_out  -= old_link_stats.pkts_out;
1230
1231    slprintf(numbuf, sizeof(numbuf), "%u", link_connect_time);
1232    script_setenv("CONNECT_TIME", numbuf, 0);
1233    slprintf(numbuf, sizeof(numbuf), "%u", link_stats.bytes_out);
1234    script_setenv("BYTES_SENT", numbuf, 0);
1235    slprintf(numbuf, sizeof(numbuf), "%u", link_stats.bytes_in);
1236    script_setenv("BYTES_RCVD", numbuf, 0);
1237}
1238
1239
1240struct	callout {
1241    struct timeval	c_time;		/* time at which to call routine */
1242    void		*c_arg;		/* argument to routine */
1243    void		(*c_func) __P((void *)); /* routine */
1244    struct		callout *c_next;
1245};
1246
1247static struct callout *callout = NULL;	/* Callout list */
1248static struct timeval timenow;		/* Current time */
1249
1250/*
1251 * timeout - Schedule a timeout.
1252 */
1253void
1254timeout(func, arg, secs, usecs)
1255    void (*func) __P((void *));
1256    void *arg;
1257    int secs, usecs;
1258{
1259    struct callout *newp, *p, **pp;
1260
1261    /*
1262     * Allocate timeout.
1263     */
1264    if ((newp = (struct callout *) malloc(sizeof(struct callout))) == NULL)
1265	fatal("Out of memory in timeout()!");
1266    newp->c_arg = arg;
1267    newp->c_func = func;
1268    gettimeofday(&timenow, NULL);
1269    newp->c_time.tv_sec = timenow.tv_sec + secs;
1270    newp->c_time.tv_usec = timenow.tv_usec + usecs;
1271    if (newp->c_time.tv_usec >= 1000000) {
1272	newp->c_time.tv_sec += newp->c_time.tv_usec / 1000000;
1273	newp->c_time.tv_usec %= 1000000;
1274    }
1275
1276    /*
1277     * Find correct place and link it in.
1278     */
1279    for (pp = &callout; (p = *pp); pp = &p->c_next)
1280	if (newp->c_time.tv_sec < p->c_time.tv_sec
1281	    || (newp->c_time.tv_sec == p->c_time.tv_sec
1282		&& newp->c_time.tv_usec < p->c_time.tv_usec))
1283	    break;
1284    newp->c_next = p;
1285    *pp = newp;
1286}
1287
1288
1289/*
1290 * untimeout - Unschedule a timeout.
1291 */
1292void
1293untimeout(func, arg)
1294    void (*func) __P((void *));
1295    void *arg;
1296{
1297    struct callout **copp, *freep;
1298
1299    /*
1300     * Find first matching timeout and remove it from the list.
1301     */
1302    for (copp = &callout; (freep = *copp); copp = &freep->c_next)
1303	if (freep->c_func == func && freep->c_arg == arg) {
1304	    *copp = freep->c_next;
1305	    free((char *) freep);
1306	    break;
1307	}
1308}
1309
1310
1311/*
1312 * calltimeout - Call any timeout routines which are now due.
1313 */
1314static void
1315calltimeout()
1316{
1317    struct callout *p;
1318
1319    while (callout != NULL) {
1320	p = callout;
1321
1322	if (gettimeofday(&timenow, NULL) < 0)
1323	    fatal("Failed to get time of day: %m");
1324	if (!(p->c_time.tv_sec < timenow.tv_sec
1325	      || (p->c_time.tv_sec == timenow.tv_sec
1326		  && p->c_time.tv_usec <= timenow.tv_usec)))
1327	    break;		/* no, it's not time yet */
1328
1329	callout = p->c_next;
1330	(*p->c_func)(p->c_arg);
1331
1332	free((char *) p);
1333    }
1334}
1335
1336
1337/*
1338 * timeleft - return the length of time until the next timeout is due.
1339 */
1340static struct timeval *
1341timeleft(tvp)
1342    struct timeval *tvp;
1343{
1344    if (callout == NULL)
1345	return NULL;
1346
1347    gettimeofday(&timenow, NULL);
1348    tvp->tv_sec = callout->c_time.tv_sec - timenow.tv_sec;
1349    tvp->tv_usec = callout->c_time.tv_usec - timenow.tv_usec;
1350    if (tvp->tv_usec < 0) {
1351	tvp->tv_usec += 1000000;
1352	tvp->tv_sec -= 1;
1353    }
1354    if (tvp->tv_sec < 0)
1355	tvp->tv_sec = tvp->tv_usec = 0;
1356
1357    return tvp;
1358}
1359
1360
1361/*
1362 * kill_my_pg - send a signal to our process group, and ignore it ourselves.
1363 * We assume that sig is currently blocked.
1364 */
1365static void
1366kill_my_pg(sig)
1367    int sig;
1368{
1369    struct sigaction act, oldact;
1370
1371    sigemptyset(&act.sa_mask);		/* unnecessary in fact */
1372    act.sa_handler = SIG_IGN;
1373    act.sa_flags = 0;
1374    kill(0, sig);
1375    /*
1376     * The kill() above made the signal pending for us, as well as
1377     * the rest of our process group, but we don't want it delivered
1378     * to us.  It is blocked at the moment.  Setting it to be ignored
1379     * will cause the pending signal to be discarded.  If we did the
1380     * kill() after setting the signal to be ignored, it is unspecified
1381     * (by POSIX) whether the signal is immediately discarded or left
1382     * pending, and in fact Linux would leave it pending, and so it
1383     * would be delivered after the current signal handler exits,
1384     * leading to an infinite loop.
1385     */
1386    sigaction(sig, &act, &oldact);
1387    sigaction(sig, &oldact, NULL);
1388}
1389
1390
1391/*
1392 * hup - Catch SIGHUP signal.
1393 *
1394 * Indicates that the physical layer has been disconnected.
1395 * We don't rely on this indication; if the user has sent this
1396 * signal, we just take the link down.
1397 */
1398static void
1399hup(sig)
1400    int sig;
1401{
1402    /* can't log a message here, it can deadlock */
1403    got_sighup = 1;
1404    if (conn_running)
1405	/* Send the signal to the [dis]connector process(es) also */
1406	kill_my_pg(sig);
1407    notify(sigreceived, sig);
1408    if (waiting)
1409	siglongjmp(sigjmp, 1);
1410}
1411
1412
1413/*
1414 * term - Catch SIGTERM signal and SIGINT signal (^C/del).
1415 *
1416 * Indicates that we should initiate a graceful disconnect and exit.
1417 */
1418/*ARGSUSED*/
1419static void
1420term(sig)
1421    int sig;
1422{
1423    /* can't log a message here, it can deadlock */
1424    got_sigterm = sig;
1425    if (conn_running)
1426	/* Send the signal to the [dis]connector process(es) also */
1427	kill_my_pg(sig);
1428    notify(sigreceived, sig);
1429    if (waiting)
1430	siglongjmp(sigjmp, 1);
1431}
1432
1433
1434/*
1435 * chld - Catch SIGCHLD signal.
1436 * Sets a flag so we will call reap_kids in the mainline.
1437 */
1438static void
1439chld(sig)
1440    int sig;
1441{
1442    got_sigchld = 1;
1443    if (waiting)
1444	siglongjmp(sigjmp, 1);
1445}
1446
1447
1448/*
1449 * toggle_debug - Catch SIGUSR1 signal.
1450 *
1451 * Toggle debug flag.
1452 */
1453/*ARGSUSED*/
1454static void
1455toggle_debug(sig)
1456    int sig;
1457{
1458    debug = !debug;
1459    if (debug) {
1460	setlogmask(LOG_UPTO(LOG_DEBUG));
1461    } else {
1462	setlogmask(LOG_UPTO(LOG_WARNING));
1463    }
1464}
1465
1466
1467/*
1468 * open_ccp - Catch SIGUSR2 signal.
1469 *
1470 * Try to (re)negotiate compression.
1471 */
1472/*ARGSUSED*/
1473static void
1474open_ccp(sig)
1475    int sig;
1476{
1477    got_sigusr2 = 1;
1478    if (waiting)
1479	siglongjmp(sigjmp, 1);
1480}
1481
1482
1483/*
1484 * bad_signal - We've caught a fatal signal.  Clean up state and exit.
1485 */
1486static void
1487bad_signal(sig)
1488    int sig;
1489{
1490    static int crashed = 0;
1491
1492    if (crashed)
1493	_exit(127);
1494    crashed = 1;
1495    error("Fatal signal %d", sig);
1496    if (conn_running)
1497	kill_my_pg(SIGTERM);
1498    notify(sigreceived, sig);
1499    die(127);
1500}
1501
1502/*
1503 * safe_fork - Create a child process.  The child closes all the
1504 * file descriptors that we don't want to leak to a script.
1505 * The parent waits for the child to do this before returning.
1506 * This also arranges for the specified fds to be dup'd to
1507 * fds 0, 1, 2 in the child.
1508 */
1509pid_t
1510safe_fork(int infd, int outfd, int errfd)
1511{
1512	pid_t pid;
1513	int fd, pipefd[2];
1514	char buf[1];
1515
1516	/* make sure fds 0, 1, 2 are occupied (probably not necessary) */
1517	while ((fd = dup(fd_devnull)) >= 0) {
1518		if (fd > 2) {
1519			close(fd);
1520			break;
1521		}
1522	}
1523
1524	if (pipe(pipefd) == -1)
1525		pipefd[0] = pipefd[1] = -1;
1526	pid = fork();
1527	if (pid < 0) {
1528		error("fork failed: %m");
1529		return -1;
1530	}
1531	if (pid > 0) {
1532		/* parent */
1533		close(pipefd[1]);
1534		/* this read() blocks until the close(pipefd[1]) below */
1535		complete_read(pipefd[0], buf, 1);
1536		close(pipefd[0]);
1537		return pid;
1538	}
1539
1540	/* Executing in the child */
1541	sys_close();
1542#ifdef USE_TDB
1543	tdb_close(pppdb);
1544#endif
1545
1546	/* make sure infd, outfd and errfd won't get tromped on below */
1547	if (infd == 1 || infd == 2)
1548		infd = dup(infd);
1549	if (outfd == 0 || outfd == 2)
1550		outfd = dup(outfd);
1551	if (errfd == 0 || errfd == 1)
1552		errfd = dup(errfd);
1553
1554	/* dup the in, out, err fds to 0, 1, 2 */
1555	if (infd != 0)
1556		dup2(infd, 0);
1557	if (outfd != 1)
1558		dup2(outfd, 1);
1559	if (errfd != 2)
1560		dup2(errfd, 2);
1561
1562#ifndef ANDROID_CHANGES
1563	closelog();
1564#endif
1565	if (log_to_fd > 2)
1566		close(log_to_fd);
1567	if (the_channel->close)
1568		(*the_channel->close)();
1569	else
1570		close(devfd);	/* some plugins don't have a close function */
1571	close(fd_ppp);
1572	close(fd_devnull);
1573	if (infd != 0)
1574		close(infd);
1575	if (outfd != 1)
1576		close(outfd);
1577	if (errfd != 2)
1578		close(errfd);
1579
1580	notify(fork_notifier, 0);
1581	close(pipefd[0]);
1582	/* this close unblocks the read() call above in the parent */
1583	close(pipefd[1]);
1584
1585	return 0;
1586}
1587
1588/*
1589 * device_script - run a program to talk to the specified fds
1590 * (e.g. to run the connector or disconnector script).
1591 * stderr gets connected to the log fd or to the _PATH_CONNERRS file.
1592 */
1593int
1594device_script(program, in, out, dont_wait)
1595    char *program;
1596    int in, out;
1597    int dont_wait;
1598{
1599    int pid;
1600    int status = -1;
1601    int errfd;
1602
1603    if (log_to_fd >= 0)
1604	errfd = log_to_fd;
1605    else
1606	errfd = open(_PATH_CONNERRS, O_WRONLY | O_APPEND | O_CREAT, 0600);
1607
1608    ++conn_running;
1609    pid = safe_fork(in, out, errfd);
1610
1611    if (pid != 0 && log_to_fd < 0)
1612	close(errfd);
1613
1614    if (pid < 0) {
1615	--conn_running;
1616	error("Failed to create child process: %m");
1617	return -1;
1618    }
1619
1620    if (pid != 0) {
1621	if (dont_wait) {
1622	    record_child(pid, program, NULL, NULL);
1623	    status = 0;
1624	} else {
1625	    while (waitpid(pid, &status, 0) < 0) {
1626		if (errno == EINTR)
1627		    continue;
1628		fatal("error waiting for (dis)connection process: %m");
1629	    }
1630	    --conn_running;
1631	}
1632	return (status == 0 ? 0 : -1);
1633    }
1634
1635    /* here we are executing in the child */
1636
1637    setgid(getgid());
1638    setuid(uid);
1639    if (getuid() != uid) {
1640	fprintf(stderr, "pppd: setuid failed\n");
1641	exit(1);
1642    }
1643    execl("/system/bin/sh", "sh", "-c", program, NULL);
1644    perror("pppd: could not exec /bin/sh");
1645    exit(99);
1646    /* NOTREACHED */
1647}
1648
1649
1650/*
1651 * run-program - execute a program with given arguments,
1652 * but don't wait for it.
1653 * If the program can't be executed, logs an error unless
1654 * must_exist is 0 and the program file doesn't exist.
1655 * Returns -1 if it couldn't fork, 0 if the file doesn't exist
1656 * or isn't an executable plain file, or the process ID of the child.
1657 * If done != NULL, (*done)(arg) will be called later (within
1658 * reap_kids) iff the return value is > 0.
1659 */
1660pid_t
1661run_program(prog, args, must_exist, done, arg)
1662    char *prog;
1663    char **args;
1664    int must_exist;
1665    void (*done) __P((void *));
1666    void *arg;
1667{
1668    int pid;
1669    struct stat sbuf;
1670
1671#ifdef ANDROID_CHANGES
1672    /* Originally linkname is used to create named pid files, which is
1673    * meaningless to android. Here we use it as a suffix of program names,
1674    * so different users can run their own program by specifying it. For
1675    * example, "/etc/ppp/ip-up-vpn" will be executed when IPCP is up and
1676    * linkname is "vpn". Note that "/" is not allowed for security reasons. */
1677    char file[MAXPATHLEN];
1678
1679    if (linkname[0] && !strchr(linkname, '/')) {
1680        snprintf(file, MAXPATHLEN, "%s-%s", prog, linkname);
1681        file[MAXPATHLEN - 1] = '\0';
1682        prog = file;
1683    }
1684#endif
1685
1686    /*
1687     * First check if the file exists and is executable.
1688     * We don't use access() because that would use the
1689     * real user-id, which might not be root, and the script
1690     * might be accessible only to root.
1691     */
1692    errno = EINVAL;
1693    if (stat(prog, &sbuf) < 0 || !S_ISREG(sbuf.st_mode)
1694	|| (sbuf.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0) {
1695	if (must_exist || errno != ENOENT)
1696	    warn("Can't execute %s: %m", prog);
1697	return 0;
1698    }
1699
1700    pid = safe_fork(fd_devnull, fd_devnull, fd_devnull);
1701    if (pid == -1) {
1702	error("Failed to create child process for %s: %m", prog);
1703	return -1;
1704    }
1705    if (pid != 0) {
1706	if (debug)
1707	    dbglog("Script %s started (pid %d)", prog, pid);
1708	record_child(pid, prog, done, arg);
1709	return pid;
1710    }
1711
1712    /* Leave the current location */
1713    (void) setsid();	/* No controlling tty. */
1714    (void) umask (S_IRWXG|S_IRWXO);
1715    (void) chdir ("/");	/* no current directory. */
1716    setuid(0);		/* set real UID = root */
1717    setgid(getegid());
1718
1719#ifdef BSD
1720    /* Force the priority back to zero if pppd is running higher. */
1721    if (setpriority (PRIO_PROCESS, 0, 0) < 0)
1722	warn("can't reset priority to 0: %m");
1723#endif
1724
1725    /* run the program */
1726    execve(prog, args, script_env);
1727    if (must_exist || errno != ENOENT) {
1728#ifndef ANDROID_CHANGES
1729	/* have to reopen the log, there's nowhere else
1730	   for the message to go. */
1731	reopen_log();
1732	syslog(LOG_ERR, "Can't execute %s: %m", prog);
1733	closelog();
1734#else
1735	error("Can't execute %s: %m", prog);
1736#endif
1737    }
1738    _exit(-1);
1739}
1740
1741
1742/*
1743 * record_child - add a child process to the list for reap_kids
1744 * to use.
1745 */
1746void
1747record_child(pid, prog, done, arg)
1748    int pid;
1749    char *prog;
1750    void (*done) __P((void *));
1751    void *arg;
1752{
1753    struct subprocess *chp;
1754
1755    ++n_children;
1756
1757    chp = (struct subprocess *) malloc(sizeof(struct subprocess));
1758    if (chp == NULL) {
1759	warn("losing track of %s process", prog);
1760    } else {
1761	chp->pid = pid;
1762	chp->prog = prog;
1763	chp->done = done;
1764	chp->arg = arg;
1765	chp->next = children;
1766	children = chp;
1767    }
1768}
1769
1770/*
1771 * childwait_end - we got fed up waiting for the child processes to
1772 * exit, send them all a SIGTERM.
1773 */
1774static void
1775childwait_end(arg)
1776    void *arg;
1777{
1778    struct subprocess *chp;
1779
1780    for (chp = children; chp != NULL; chp = chp->next) {
1781	if (debug)
1782	    dbglog("sending SIGTERM to process %d", chp->pid);
1783	kill(chp->pid, SIGTERM);
1784    }
1785    childwait_done = 1;
1786}
1787
1788/*
1789 * reap_kids - get status from any dead child processes,
1790 * and log a message for abnormal terminations.
1791 */
1792static int
1793reap_kids()
1794{
1795    int pid, status;
1796    struct subprocess *chp, **prevp;
1797
1798    if (n_children == 0)
1799	return 0;
1800    while ((pid = waitpid(-1, &status, WNOHANG)) != -1 && pid != 0) {
1801	for (prevp = &children; (chp = *prevp) != NULL; prevp = &chp->next) {
1802	    if (chp->pid == pid) {
1803		--n_children;
1804		*prevp = chp->next;
1805		break;
1806	    }
1807	}
1808	if (WIFSIGNALED(status)) {
1809	    warn("Child process %s (pid %d) terminated with signal %d",
1810		 (chp? chp->prog: "??"), pid, WTERMSIG(status));
1811	} else if (debug)
1812	    dbglog("Script %s finished (pid %d), status = 0x%x",
1813		   (chp? chp->prog: "??"), pid,
1814		   WIFEXITED(status) ? WEXITSTATUS(status) : status);
1815	if (chp && chp->done)
1816	    (*chp->done)(chp->arg);
1817	if (chp)
1818	    free(chp);
1819    }
1820    if (pid == -1) {
1821	if (errno == ECHILD)
1822	    return -1;
1823	if (errno != EINTR)
1824	    error("Error waiting for child process: %m");
1825    }
1826    return 0;
1827}
1828
1829/*
1830 * add_notifier - add a new function to be called when something happens.
1831 */
1832void
1833add_notifier(notif, func, arg)
1834    struct notifier **notif;
1835    notify_func func;
1836    void *arg;
1837{
1838    struct notifier *np;
1839
1840    np = malloc(sizeof(struct notifier));
1841    if (np == 0)
1842	novm("notifier struct");
1843    np->next = *notif;
1844    np->func = func;
1845    np->arg = arg;
1846    *notif = np;
1847}
1848
1849/*
1850 * remove_notifier - remove a function from the list of things to
1851 * be called when something happens.
1852 */
1853void
1854remove_notifier(notif, func, arg)
1855    struct notifier **notif;
1856    notify_func func;
1857    void *arg;
1858{
1859    struct notifier *np;
1860
1861    for (; (np = *notif) != 0; notif = &np->next) {
1862	if (np->func == func && np->arg == arg) {
1863	    *notif = np->next;
1864	    free(np);
1865	    break;
1866	}
1867    }
1868}
1869
1870/*
1871 * notify - call a set of functions registered with add_notifier.
1872 */
1873void
1874notify(notif, val)
1875    struct notifier *notif;
1876    int val;
1877{
1878    struct notifier *np;
1879
1880    while ((np = notif) != 0) {
1881	notif = np->next;
1882	(*np->func)(np->arg, val);
1883    }
1884}
1885
1886/*
1887 * novm - log an error message saying we ran out of memory, and die.
1888 */
1889void
1890novm(msg)
1891    char *msg;
1892{
1893    fatal("Virtual memory exhausted allocating %s\n", msg);
1894}
1895
1896/*
1897 * script_setenv - set an environment variable value to be used
1898 * for scripts that we run (e.g. ip-up, auth-up, etc.)
1899 */
1900void
1901script_setenv(var, value, iskey)
1902    char *var, *value;
1903    int iskey;
1904{
1905    size_t varl = strlen(var);
1906    size_t vl = varl + strlen(value) + 2;
1907    int i;
1908    char *p, *newstring;
1909
1910    newstring = (char *) malloc(vl+1);
1911    if (newstring == 0)
1912	return;
1913    *newstring++ = iskey;
1914    slprintf(newstring, vl, "%s=%s", var, value);
1915
1916    /* check if this variable is already set */
1917    if (script_env != 0) {
1918	for (i = 0; (p = script_env[i]) != 0; ++i) {
1919	    if (strncmp(p, var, varl) == 0 && p[varl] == '=') {
1920#ifdef USE_TDB
1921		if (p[-1] && pppdb != NULL)
1922		    delete_db_key(p);
1923#endif
1924		free(p-1);
1925		script_env[i] = newstring;
1926#ifdef USE_TDB
1927		if (iskey && pppdb != NULL)
1928		    add_db_key(newstring);
1929		update_db_entry();
1930#endif
1931		return;
1932	    }
1933	}
1934    } else {
1935	/* no space allocated for script env. ptrs. yet */
1936	i = 0;
1937	script_env = (char **) malloc(16 * sizeof(char *));
1938	if (script_env == 0)
1939	    return;
1940	s_env_nalloc = 16;
1941    }
1942
1943    /* reallocate script_env with more space if needed */
1944    if (i + 1 >= s_env_nalloc) {
1945	int new_n = i + 17;
1946	char **newenv = (char **) realloc((void *)script_env,
1947					  new_n * sizeof(char *));
1948	if (newenv == 0)
1949	    return;
1950	script_env = newenv;
1951	s_env_nalloc = new_n;
1952    }
1953
1954    script_env[i] = newstring;
1955    script_env[i+1] = 0;
1956
1957#ifdef USE_TDB
1958    if (pppdb != NULL) {
1959	if (iskey)
1960	    add_db_key(newstring);
1961	update_db_entry();
1962    }
1963#endif
1964}
1965
1966/*
1967 * script_unsetenv - remove a variable from the environment
1968 * for scripts.
1969 */
1970void
1971script_unsetenv(var)
1972    char *var;
1973{
1974    int vl = strlen(var);
1975    int i;
1976    char *p;
1977
1978    if (script_env == 0)
1979	return;
1980    for (i = 0; (p = script_env[i]) != 0; ++i) {
1981	if (strncmp(p, var, vl) == 0 && p[vl] == '=') {
1982#ifdef USE_TDB
1983	    if (p[-1] && pppdb != NULL)
1984		delete_db_key(p);
1985#endif
1986	    free(p-1);
1987	    while ((script_env[i] = script_env[i+1]) != 0)
1988		++i;
1989	    break;
1990	}
1991    }
1992#ifdef USE_TDB
1993    if (pppdb != NULL)
1994	update_db_entry();
1995#endif
1996}
1997
1998/*
1999 * Any arbitrary string used as a key for locking the database.
2000 * It doesn't matter what it is as long as all pppds use the same string.
2001 */
2002#define PPPD_LOCK_KEY	"pppd lock"
2003
2004/*
2005 * lock_db - get an exclusive lock on the TDB database.
2006 * Used to ensure atomicity of various lookup/modify operations.
2007 */
2008void lock_db()
2009{
2010#ifdef USE_TDB
2011	TDB_DATA key;
2012
2013	key.dptr = PPPD_LOCK_KEY;
2014	key.dsize = strlen(key.dptr);
2015	tdb_chainlock(pppdb, key);
2016#endif
2017}
2018
2019/*
2020 * unlock_db - remove the exclusive lock obtained by lock_db.
2021 */
2022void unlock_db()
2023{
2024#ifdef USE_TDB
2025	TDB_DATA key;
2026
2027	key.dptr = PPPD_LOCK_KEY;
2028	key.dsize = strlen(key.dptr);
2029	tdb_chainunlock(pppdb, key);
2030#endif
2031}
2032
2033#ifdef USE_TDB
2034/*
2035 * update_db_entry - update our entry in the database.
2036 */
2037static void
2038update_db_entry()
2039{
2040    TDB_DATA key, dbuf;
2041    int vlen, i;
2042    char *p, *q, *vbuf;
2043
2044    if (script_env == NULL)
2045	return;
2046    vlen = 0;
2047    for (i = 0; (p = script_env[i]) != 0; ++i)
2048	vlen += strlen(p) + 1;
2049    vbuf = malloc(vlen + 1);
2050    if (vbuf == 0)
2051	novm("database entry");
2052    q = vbuf;
2053    for (i = 0; (p = script_env[i]) != 0; ++i)
2054	q += slprintf(q, vbuf + vlen - q, "%s;", p);
2055
2056    key.dptr = db_key;
2057    key.dsize = strlen(db_key);
2058    dbuf.dptr = vbuf;
2059    dbuf.dsize = vlen;
2060    if (tdb_store(pppdb, key, dbuf, TDB_REPLACE))
2061	error("tdb_store failed: %s", tdb_error(pppdb));
2062
2063    if (vbuf)
2064        free(vbuf);
2065
2066}
2067
2068/*
2069 * add_db_key - add a key that we can use to look up our database entry.
2070 */
2071static void
2072add_db_key(str)
2073    const char *str;
2074{
2075    TDB_DATA key, dbuf;
2076
2077    key.dptr = (char *) str;
2078    key.dsize = strlen(str);
2079    dbuf.dptr = db_key;
2080    dbuf.dsize = strlen(db_key);
2081    if (tdb_store(pppdb, key, dbuf, TDB_REPLACE))
2082	error("tdb_store key failed: %s", tdb_error(pppdb));
2083}
2084
2085/*
2086 * delete_db_key - delete a key for looking up our database entry.
2087 */
2088static void
2089delete_db_key(str)
2090    const char *str;
2091{
2092    TDB_DATA key;
2093
2094    key.dptr = (char *) str;
2095    key.dsize = strlen(str);
2096    tdb_delete(pppdb, key);
2097}
2098
2099/*
2100 * cleanup_db - delete all the entries we put in the database.
2101 */
2102static void
2103cleanup_db()
2104{
2105    TDB_DATA key;
2106    int i;
2107    char *p;
2108
2109    key.dptr = db_key;
2110    key.dsize = strlen(db_key);
2111    tdb_delete(pppdb, key);
2112    for (i = 0; (p = script_env[i]) != 0; ++i)
2113	if (p[-1])
2114	    delete_db_key(p);
2115}
2116#endif /* USE_TDB */
2117