Initial revision

1 files changed, 1831 insertions, 0 deletions

diff --git a/mdk-stage1/ppp/pppd/main.c b/mdk-stage1/ppp/pppd/main.c
new file mode 100644
index 000000000..8789d3b1d
--- /dev/null
+++ b/mdk-stage1/ppp/pppd/main.c
@@ -0,0 +1,1831 @@
+/*
+ * main.c - Point-to-Point Protocol main module
+ *
+ * Copyright (c) 1989 Carnegie Mellon University.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by Carnegie Mellon University.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#define RCSID	"$Id$"
+
+#include <stdio.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <signal.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <syslog.h>
+#include <netdb.h>
+#include <utmp.h>
+#include <pwd.h>
+#include <setjmp.h>
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include "pppd.h"
+#include "magic.h"
+#include "fsm.h"
+#include "lcp.h"
+#include "ipcp.h"
+#ifdef INET6
+#include "ipv6cp.h"
+#endif
+#include "upap.h"
+#include "chap.h"
+#include "ccp.h"
+#include "pathnames.h"
+#include "tdb.h"
+
+#ifdef CBCP_SUPPORT
+#include "cbcp.h"
+#endif
+
+#ifdef IPX_CHANGE
+#include "ipxcp.h"
+#endif /* IPX_CHANGE */
+#ifdef AT_CHANGE
+#include "atcp.h"
+#endif
+
+static const char rcsid[] = RCSID;
+
+/* interface vars */
+char ifname[32];		/* Interface name */
+int ifunit;			/* Interface unit number */
+
+struct channel *the_channel;
+
+char *progname;			/* Name of this program */
+char hostname[MAXNAMELEN];	/* Our hostname */
+static char pidfilename[MAXPATHLEN];	/* name of pid file */
+static char linkpidfile[MAXPATHLEN];	/* name of linkname pid file */
+char ppp_devnam[MAXPATHLEN];	/* name of PPP tty (maybe ttypx) */
+uid_t uid;			/* Our real user-id */
+struct notifier *pidchange = NULL;
+struct notifier *phasechange = NULL;
+struct notifier *exitnotify = NULL;
+struct notifier *sigreceived = NULL;
+
+int hungup;			/* terminal has been hung up */
+int privileged;			/* we're running as real uid root */
+int need_holdoff;		/* need holdoff period before restarting */
+int detached;			/* have detached from terminal */
+volatile int status;		/* exit status for pppd */
+int unsuccess;			/* # unsuccessful connection attempts */
+int do_callback;		/* != 0 if we should do callback next */
+int doing_callback;		/* != 0 if we are doing callback */
+TDB_CONTEXT *pppdb;		/* database for storing status etc. */
+char db_key[32];
+
+int (*holdoff_hook) __P((void)) = NULL;
+int (*new_phase_hook) __P((int)) = NULL;
+
+static int conn_running;	/* we have a [dis]connector running */
+static int devfd;		/* fd of underlying device */
+static int fd_ppp = -1;		/* fd for talking PPP */
+static int fd_loop;		/* fd for getting demand-dial packets */
+
+int phase;			/* where the link is at */
+int kill_link;
+int open_ccp_flag;
+int listen_time;
+int got_sigusr2;
+int got_sigterm;
+int got_sighup;
+
+static int waiting;
+static sigjmp_buf sigjmp;
+
+char **script_env;		/* Env. variable values for scripts */
+int s_env_nalloc;		/* # words avail at script_env */
+
+u_char outpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for outgoing packet */
+u_char inpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for incoming packet */
+
+static int n_children;		/* # child processes still running */
+static int got_sigchld;		/* set if we have received a SIGCHLD */
+
+int privopen;			/* don't lock, open device as root */
+
+char *no_ppp_msg = "Sorry - this system lacks PPP kernel support\n";
+
+GIDSET_TYPE groups[NGROUPS_MAX];/* groups the user is in */
+int ngroups;			/* How many groups valid in groups */
+
+static struct timeval start_time;	/* Time when link was started. */
+
+struct pppd_stats link_stats;
+int link_connect_time;
+int link_stats_valid;
+
+/*
+ * We maintain a list of child process pids and
+ * functions to call when they exit.
+ */
+struct subprocess {
+    pid_t	pid;
+    char	*prog;
+    void	(*done) __P((void *));
+    void	*arg;
+    struct subprocess *next;
+};
+
+static struct subprocess *children;
+
+/* Prototypes for procedures local to this file. */
+
+static void setup_signals __P((void));
+static void create_pidfile __P((void));
+static void create_linkpidfile __P((void));
+static void cleanup __P((void));
+static void get_input __P((void));
+static void calltimeout __P((void));
+static struct timeval *timeleft __P((struct timeval *));
+static void kill_my_pg __P((int));
+static void hup __P((int));
+static void term __P((int));
+static void chld __P((int));
+static void toggle_debug __P((int));
+static void open_ccp __P((int));
+static void bad_signal __P((int));
+static void holdoff_end __P((void *));
+static int reap_kids __P((int waitfor));
+static void update_db_entry __P((void));
+static void add_db_key __P((const char *));
+static void delete_db_key __P((const char *));
+static void cleanup_db __P((void));
+static void handle_events __P((void));
+
+extern	char	*ttyname __P((int));
+extern	char	*getlogin __P((void));
+int main __P((int, char *[]));
+
+#ifdef ultrix
+#undef	O_NONBLOCK
+#define	O_NONBLOCK	O_NDELAY
+#endif
+
+#ifdef ULTRIX
+#define setlogmask(x)
+#endif
+
+/*
+ * PPP Data Link Layer "protocol" table.
+ * One entry per supported protocol.
+ * The last entry must be NULL.
+ */
+struct protent *protocols[] = {
+    &lcp_protent,
+    &pap_protent,
+    &chap_protent,
+#ifdef CBCP_SUPPORT
+    &cbcp_protent,
+#endif
+    &ipcp_protent,
+#ifdef INET6
+    &ipv6cp_protent,
+#endif
+    &ccp_protent,
+#ifdef IPX_CHANGE
+    &ipxcp_protent,
+#endif
+#ifdef AT_CHANGE
+    &atcp_protent,
+#endif
+    NULL
+};
+
+/*
+ * If PPP_DRV_NAME is not defined, use the default "ppp" as the device name.
+ */
+#if !defined(PPP_DRV_NAME)
+#define PPP_DRV_NAME	"ppp"
+#endif /* !defined(PPP_DRV_NAME) */
+
+int
+main(argc, argv)
+    int argc;
+    char *argv[];
+{
+    int i, t;
+    char *p;
+    struct passwd *pw;
+    struct protent *protp;
+    char numbuf[16];
+
+    new_phase(PHASE_INITIALIZE);
+
+    /*
+     * Ensure that fds 0, 1, 2 are open, to /dev/null if nowhere else.
+     * This way we can close 0, 1, 2 in detach() without clobbering
+     * a fd that we are using.
+     */
+    if ((i = open("/dev/null", O_RDWR)) >= 0) {
+	while (0 <= i && i <= 2)
+	    i = dup(i);
+	if (i >= 0)
+	    close(i);
+    }
+
+    script_env = NULL;
+
+    /* Initialize syslog facilities */
+    reopen_log();
+
+    if (gethostname(hostname, MAXNAMELEN) < 0 ) {
+	option_error("Couldn't get hostname: %m");
+	exit(1);
+    }
+    hostname[MAXNAMELEN-1] = 0;
+
+    /* make sure we don't create world or group writable files. */
+    umask(umask(0777) | 022);
+
+    uid = getuid();
+    privileged = uid == 0;
+    slprintf(numbuf, sizeof(numbuf), "%d", uid);
+    script_setenv("ORIG_UID", numbuf, 0);
+
+    ngroups = getgroups(NGROUPS_MAX, groups);
+
+    /*
+     * Initialize magic number generator now so that protocols may
+     * use magic numbers in initialization.
+     */
+    magic_init();
+
+    /*
+     * Initialize each protocol.
+     */
+    for (i = 0; (protp = protocols[i]) != NULL; ++i)
+        (*protp->init)(0);
+
+    /*
+     * Initialize the default channel.
+     */
+    tty_init();
+
+    progname = *argv;
+
+    /*
+     * Parse, in order, the system options file, the user's options file,
+     * and the command line arguments.
+     */
+    if (!options_from_file(_PATH_SYSOPTIONS, !privileged, 0, 1)
+	|| !options_from_user()
+	|| !parse_args(argc-1, argv+1))
+	exit(EXIT_OPTION_ERROR);
+    devnam_fixed = 1;		/* can no longer change device name */
+
+    /*
+     * Work out the device name, if it hasn't already been specified,
+     * and parse the tty's options file.
+     */
+    if (the_channel->process_extra_options)
+	(*the_channel->process_extra_options)();
+
+    if (debug)
+	setlogmask(LOG_UPTO(LOG_DEBUG));
+
+    /*
+     * Check that we are running as root.
+     */
+    if (geteuid() != 0) {
+	option_error("must be root to run %s, since it is not setuid-root",
+		     argv[0]);
+	exit(EXIT_NOT_ROOT);
+    }
+
+    if (!ppp_available()) {
+	option_error("%s", no_ppp_msg);
+	exit(EXIT_NO_KERNEL_SUPPORT);
+    }
+
+    /*
+     * Check that the options given are valid and consistent.
+     */
+    check_options();
+    if (!sys_check_options())
+	exit(EXIT_OPTION_ERROR);
+    auth_check_options();
+#ifdef HAVE_MULTILINK
+    mp_check_options();
+#endif
+    for (i = 0; (protp = protocols[i]) != NULL; ++i)
+	if (protp->check_options != NULL)
+	    (*protp->check_options)();
+    if (the_channel->check_options)
+	(*the_channel->check_options)();
+
+
+    if (dump_options || dryrun) {
+	init_pr_log(NULL, LOG_INFO);
+	print_options(pr_log, NULL);
+	end_pr_log();
+	if (dryrun)
+	    die(0);
+    }
+
+    /*
+     * Initialize system-dependent stuff.
+     */
+    sys_init();
+
+    pppdb = tdb_open(_PATH_PPPDB, 0, 0, O_RDWR|O_CREAT, 0644);
+    if (pppdb != NULL) {
+	slprintf(db_key, sizeof(db_key), "pppd%d", getpid());
+	update_db_entry();
+    } else {
+	warn("Warning: couldn't open ppp database %s", _PATH_PPPDB);
+	if (multilink) {
+	    warn("Warning: disabling multilink");
+	    multilink = 0;
+	}
+    }
+
+    /*
+     * Detach ourselves from the terminal, if required,
+     * and identify who is running us.
+     */
+    if (!nodetach && !updetach)
+	detach();
+    p = getlogin();
+    if (p == NULL) {
+	pw = getpwuid(uid);
+	if (pw != NULL && pw->pw_name != NULL)
+	    p = pw->pw_name;
+	else
+	    p = "(unknown)";
+    }
+    syslog(LOG_NOTICE, "pppd %s started by %s, uid %d", VERSION, p, uid);
+    script_setenv("PPPLOGNAME", p, 0);
+
+    if (devnam[0])
+	script_setenv("DEVICE", devnam, 1);
+    slprintf(numbuf, sizeof(numbuf), "%d", getpid());
+    script_setenv("PPPD_PID", numbuf, 1);
+
+    setup_signals();
+
+    waiting = 0;
+
+    create_linkpidfile();
+
+    /*
+     * If we're doing dial-on-demand, set up the interface now.
+     */
+    if (demand) {
+	/*
+	 * Open the loopback channel and set it up to be the ppp interface.
+	 */
+	tdb_writelock(pppdb);
+	fd_loop = open_ppp_loopback();
+	set_ifunit(1);
+	tdb_writeunlock(pppdb);
+
+	/*
+	 * Configure the interface and mark it up, etc.
+	 */
+	demand_conf();
+    }
+
+    do_callback = 0;
+    for (;;) {
+
+	listen_time = 0;
+	need_holdoff = 1;
+	devfd = -1;
+	status = EXIT_OK;
+	++unsuccess;
+	doing_callback = do_callback;
+	do_callback = 0;
+
+	if (demand && !doing_callback) {
+	    /*
+	     * Don't do anything until we see some activity.
+	     */
+	    new_phase(PHASE_DORMANT);
+	    demand_unblock();
+	    add_fd(fd_loop);
+	    for (;;) {
+		handle_events();
+		if (kill_link && !persist)
+		    break;
+		if (get_loop_output())
+		    break;
+	    }
+	    remove_fd(fd_loop);
+	    if (kill_link && !persist)
+		break;
+
+	    /*
+	     * Now we want to bring up the link.
+	     */
+	    demand_block();
+	    info("Starting link");
+	}
+
+	new_phase(PHASE_SERIALCONN);
+
+	devfd = the_channel->connect();
+	if (devfd < 0)
+	    goto fail;
+
+	/* set up the serial device as a ppp interface */
+	tdb_writelock(pppdb);
+	fd_ppp = the_channel->establish_ppp(devfd);
+	if (fd_ppp < 0) {
+	    tdb_writeunlock(pppdb);
+	    status = EXIT_FATAL_ERROR;
+	    goto disconnect;
+	}
+
+	if (!demand && ifunit >= 0)
+	    set_ifunit(1);
+	tdb_writeunlock(pppdb);
+
+	/*
+	 * Start opening the connection and wait for
+	 * incoming events (reply, timeout, etc.).
+	 */
+	notice("Connect: %s <--> %s", ifname, ppp_devnam);
+	gettimeofday(&start_time, NULL);
+	link_stats_valid = 0;
+	script_unsetenv("CONNECT_TIME");
+	script_unsetenv("BYTES_SENT");
+	script_unsetenv("BYTES_RCVD");
+	lcp_lowerup(0);
+
+	add_fd(fd_ppp);
+	lcp_open(0);		/* Start protocol */
+	status = EXIT_NEGOTIATION_FAILED;
+	new_phase(PHASE_ESTABLISH);
+	while (phase != PHASE_DEAD) {
+	    handle_events();
+	    get_input();
+	    if (kill_link)
+		lcp_close(0, "User request");
+	    if (open_ccp_flag) {
+		if (phase == PHASE_NETWORK || phase == PHASE_RUNNING) {
+		    ccp_fsm[0].flags = OPT_RESTART; /* clears OPT_SILENT */
+		    (*ccp_protent.open)(0);
+		}
+	    }
+	}
+
+	/*
+	 * Print connect time and statistics.
+	 */
+	if (link_stats_valid) {
+	    int t = (link_connect_time + 5) / 6;    /* 1/10ths of minutes */
+	    info("Connect time %d.%d minutes.", t/10, t%10);
+	    info("Sent %u bytes, received %u bytes.",
+		 link_stats.bytes_out, link_stats.bytes_in);
+	}
+
+	/*
+	 * Delete pid file before disestablishing ppp.  Otherwise it
+	 * can happen that another pppd gets the same unit and then
+	 * we delete its pid file.
+	 */
+	if (!demand) {
+	    if (pidfilename[0] != 0
+		&& unlink(pidfilename) < 0 && errno != ENOENT) 
+		warn("unable to delete pid file %s: %m", pidfilename);
+	    pidfilename[0] = 0;
+	}
+
+	/*
+	 * If we may want to bring the link up again, transfer
+	 * the ppp unit back to the loopback.  Set the
+	 * real serial device back to its normal mode of operation.
+	 */
+	remove_fd(fd_ppp);
+	clean_check();
+	the_channel->disestablish_ppp(devfd);
+	fd_ppp = -1;
+	if (!hungup)
+	    lcp_lowerdown(0);
+	if (!demand)
+	    script_unsetenv("IFNAME");
+
+	/*
+	 * Run disconnector script, if requested.
+	 * XXX we may not be able to do this if the line has hung up!
+	 */
+    disconnect:
+	new_phase(PHASE_DISCONNECT);
+	the_channel->disconnect();
+
+    fail:
+	if (the_channel->cleanup)
+	    (*the_channel->cleanup)();
+
+	if (!demand) {
+	    if (pidfilename[0] != 0
+		&& unlink(pidfilename) < 0 && errno != ENOENT) 
+		warn("unable to delete pid file %s: %m", pidfilename);
+	    pidfilename[0] = 0;
+	}
+
+	if (!persist || (maxfail > 0 && unsuccess >= maxfail))
+	    break;
+
+	if (demand)
+	    demand_discard();
+	t = need_holdoff? holdoff: 0;
+	if (holdoff_hook)
+	    t = (*holdoff_hook)();
+	if (t > 0) {
+	    new_phase(PHASE_HOLDOFF);
+	    TIMEOUT(holdoff_end, NULL, t);
+	    do {
+		handle_events();
+		if (kill_link)
+		    new_phase(PHASE_DORMANT); /* allow signal to end holdoff */
+	    } while (phase == PHASE_HOLDOFF);
+	    if (!persist)
+		break;
+	}
+    }
+
+    /* Wait for scripts to finish */
+    /* XXX should have a timeout here */
+    while (n_children > 0) {
+	if (debug) {
+	    struct subprocess *chp;
+	    dbglog("Waiting for %d child processes...", n_children);
+	    for (chp = children; chp != NULL; chp = chp->next)
+		dbglog("  script %s, pid %d", chp->prog, chp->pid);
+	}
+	if (reap_kids(1) < 0)
+	    break;
+    }
+
+    die(status);
+    return 0;
+}
+
+/*
+ * handle_events - wait for something to happen and respond to it.
+ */
+static void
+handle_events()
+{
+    struct timeval timo;
+    sigset_t mask;
+
+    kill_link = open_ccp_flag = 0;
+    if (sigsetjmp(sigjmp, 1) == 0) {
+	sigprocmask(SIG_BLOCK, &mask, NULL);
+	if (got_sighup || got_sigterm || got_sigusr2 || got_sigchld) {
+	    sigprocmask(SIG_UNBLOCK, &mask, NULL);
+	} else {
+	    waiting = 1;
+	    sigprocmask(SIG_UNBLOCK, &mask, NULL);
+	    wait_input(timeleft(&timo));
+	}
+    }
+    waiting = 0;
+    calltimeout();
+    if (got_sighup) {
+	kill_link = 1;
+	got_sighup = 0;
+	if (status != EXIT_HANGUP)
+	    status = EXIT_USER_REQUEST;
+    }
+    if (got_sigterm) {
+	kill_link = 1;
+	persist = 0;
+	status = EXIT_USER_REQUEST;
+	got_sigterm = 0;
+    }
+    if (got_sigchld) {
+	reap_kids(0);	/* Don't leave dead kids lying around */
+	got_sigchld = 0;
+    }
+    if (got_sigusr2) {
+	open_ccp_flag = 1;
+	got_sigusr2 = 0;
+    }
+}
+
+/*
+ * setup_signals - initialize signal handling.
+ */
+static void
+setup_signals()
+{
+    struct sigaction sa;
+    sigset_t mask;
+
+    /*
+     * Compute mask of all interesting signals and install signal handlers
+     * for each.  Only one signal handler may be active at a time.  Therefore,
+     * all other signals should be masked when any handler is executing.
+     */
+    sigemptyset(&mask);
+    sigaddset(&mask, SIGHUP);
+    sigaddset(&mask, SIGINT);
+    sigaddset(&mask, SIGTERM);
+    sigaddset(&mask, SIGCHLD);
+    sigaddset(&mask, SIGUSR2);
+
+#define SIGNAL(s, handler)	do { \
+	sa.sa_handler = handler; \
+	if (sigaction(s, &sa, NULL) < 0) \
+	    fatal("Couldn't establish signal handler (%d): %m", s); \
+    } while (0)
+
+    sa.sa_mask = mask;
+    sa.sa_flags = 0;
+    SIGNAL(SIGHUP, hup);		/* Hangup */
+    SIGNAL(SIGINT, term);		/* Interrupt */
+    SIGNAL(SIGTERM, term);		/* Terminate */
+    SIGNAL(SIGCHLD, chld);
+
+    SIGNAL(SIGUSR1, toggle_debug);	/* Toggle debug flag */
+    SIGNAL(SIGUSR2, open_ccp);		/* Reopen CCP */
+
+    /*
+     * Install a handler for other signals which would otherwise
+     * cause pppd to exit without cleaning up.
+     */
+    SIGNAL(SIGABRT, bad_signal);
+    SIGNAL(SIGALRM, bad_signal);
+    SIGNAL(SIGFPE, bad_signal);
+    SIGNAL(SIGILL, bad_signal);
+    SIGNAL(SIGPIPE, bad_signal);
+    SIGNAL(SIGQUIT, bad_signal);
+    SIGNAL(SIGSEGV, bad_signal);
+#ifdef SIGBUS
+    SIGNAL(SIGBUS, bad_signal);
+#endif
+#ifdef SIGEMT
+    SIGNAL(SIGEMT, bad_signal);
+#endif
+#ifdef SIGPOLL
+    SIGNAL(SIGPOLL, bad_signal);
+#endif
+#ifdef SIGPROF
+    SIGNAL(SIGPROF, bad_signal);
+#endif
+#ifdef SIGSYS
+    SIGNAL(SIGSYS, bad_signal);
+#endif
+#ifdef SIGTRAP
+    SIGNAL(SIGTRAP, bad_signal);
+#endif
+#ifdef SIGVTALRM
+    SIGNAL(SIGVTALRM, bad_signal);
+#endif
+#ifdef SIGXCPU
+    SIGNAL(SIGXCPU, bad_signal);
+#endif
+#ifdef SIGXFSZ
+    SIGNAL(SIGXFSZ, bad_signal);
+#endif
+
+    /*
+     * Apparently we can get a SIGPIPE when we call syslog, if
+     * syslogd has died and been restarted.  Ignoring it seems
+     * be sufficient.
+     */
+    signal(SIGPIPE, SIG_IGN);
+}
+
+/*
+ * set_ifunit - do things we need to do once we know which ppp
+ * unit we are using.
+ */
+void
+set_ifunit(iskey)
+    int iskey;
+{
+    info("Using interface %s%d", PPP_DRV_NAME, ifunit);
+    slprintf(ifname, sizeof(ifname), "%s%d", PPP_DRV_NAME, ifunit);
+    script_setenv("IFNAME", ifname, iskey);
+    if (iskey) {
+	create_pidfile();	/* write pid to file */
+	create_linkpidfile();
+    }
+}
+
+/*
+ * detach - detach us from the controlling terminal.
+ */
+void
+detach()
+{
+    int pid;
+    char numbuf[16];
+
+    if (detached)
+	return;
+    if ((pid = fork()) < 0) {
+	error("Couldn't detach (fork failed: %m)");
+	die(1);			/* or just return? */
+    }
+    if (pid != 0) {
+	/* parent */
+	notify(pidchange, pid);
+	exit(0);		/* parent dies */
+    }
+    setsid();
+    chdir("/");
+    close(0);
+    close(1);
+    close(2);
+    detached = 1;
+    if (log_default)
+	log_to_fd = -1;
+    /* update pid files if they have been written already */
+    if (pidfilename[0])
+	create_pidfile();
+    if (linkpidfile[0])
+	create_linkpidfile();
+    slprintf(numbuf, sizeof(numbuf), "%d", getpid());
+    script_setenv("PPPD_PID", numbuf, 1);
+}
+
+/*
+ * reopen_log - (re)open our connection to syslog.
+ */
+void
+reopen_log()
+{
+#ifdef ULTRIX
+    openlog("pppd", LOG_PID);
+#else
+    openlog("pppd", LOG_PID | LOG_NDELAY, LOG_PPP);
+    setlogmask(LOG_UPTO(LOG_INFO));
+#endif
+}
+
+/*
+ * Create a file containing our process ID.
+ */
+static void
+create_pidfile()
+{
+    FILE *pidfile;
+
+    slprintf(pidfilename, sizeof(pidfilename), "%s%s.pid",
+	     _PATH_VARRUN, ifname);
+    if ((pidfile = fopen(pidfilename, "w")) != NULL) {
+	fprintf(pidfile, "%d\n", getpid());
+	(void) fclose(pidfile);
+    } else {
+	error("Failed to create pid file %s: %m", pidfilename);
+	pidfilename[0] = 0;
+    }
+}
+
+static void
+create_linkpidfile()
+{
+    FILE *pidfile;
+
+    if (linkname[0] == 0)
+	return;
+    script_setenv("LINKNAME", linkname, 1);
+    slprintf(linkpidfile, sizeof(linkpidfile), "%sppp-%s.pid",
+	     _PATH_VARRUN, linkname);
+    if ((pidfile = fopen(linkpidfile, "w")) != NULL) {
+	fprintf(pidfile, "%d\n", getpid());
+	if (ifname[0])
+	    fprintf(pidfile, "%s\n", ifname);
+	(void) fclose(pidfile);
+    } else {
+	error("Failed to create pid file %s: %m", linkpidfile);
+	linkpidfile[0] = 0;
+    }
+}
+
+/*
+ * holdoff_end - called via a timeout when the holdoff period ends.
+ */
+static void
+holdoff_end(arg)
+    void *arg;
+{
+    new_phase(PHASE_DORMANT);
+}
+
+/* List of protocol names, to make our messages a little more informative. */
+struct protocol_list {
+    u_short	proto;
+    const char	*name;
+} protocol_list[] = {
+    { 0x21,	"IP" },
+    { 0x23,	"OSI Network Layer" },
+    { 0x25,	"Xerox NS IDP" },
+    { 0x27,	"DECnet Phase IV" },
+    { 0x29,	"Appletalk" },
+    { 0x2b,	"Novell IPX" },
+    { 0x2d,	"VJ compressed TCP/IP" },
+    { 0x2f,	"VJ uncompressed TCP/IP" },
+    { 0x31,	"Bridging PDU" },
+    { 0x33,	"Stream Protocol ST-II" },
+    { 0x35,	"Banyan Vines" },
+    { 0x39,	"AppleTalk EDDP" },
+    { 0x3b,	"AppleTalk SmartBuffered" },
+    { 0x3d,	"Multi-Link" },
+    { 0x3f,	"NETBIOS Framing" },
+    { 0x41,	"Cisco Systems" },
+    { 0x43,	"Ascom Timeplex" },
+    { 0x45,	"Fujitsu Link Backup and Load Balancing (LBLB)" },
+    { 0x47,	"DCA Remote Lan" },
+    { 0x49,	"Serial Data Transport Protocol (PPP-SDTP)" },
+    { 0x4b,	"SNA over 802.2" },
+    { 0x4d,	"SNA" },
+    { 0x4f,	"IP6 Header Compression" },
+    { 0x6f,	"Stampede Bridging" },
+    { 0xfb,	"single-link compression" },
+    { 0xfd,	"1st choice compression" },
+    { 0x0201,	"802.1d Hello Packets" },
+    { 0x0203,	"IBM Source Routing BPDU" },
+    { 0x0205,	"DEC LANBridge100 Spanning Tree" },
+    { 0x0231,	"Luxcom" },
+    { 0x0233,	"Sigma Network Systems" },
+    { 0x8021,	"Internet Protocol Control Protocol" },
+    { 0x8023,	"OSI Network Layer Control Protocol" },
+    { 0x8025,	"Xerox NS IDP Control Protocol" },
+    { 0x8027,	"DECnet Phase IV Control Protocol" },
+    { 0x8029,	"Appletalk Control Protocol" },
+    { 0x802b,	"Novell IPX Control Protocol" },
+    { 0x8031,	"Bridging NCP" },
+    { 0x8033,	"Stream Protocol Control Protocol" },
+    { 0x8035,	"Banyan Vines Control Protocol" },
+    { 0x803d,	"Multi-Link Control Protocol" },
+    { 0x803f,	"NETBIOS Framing Control Protocol" },
+    { 0x8041,	"Cisco Systems Control Protocol" },
+    { 0x8043,	"Ascom Timeplex" },
+    { 0x8045,	"Fujitsu LBLB Control Protocol" },
+    { 0x8047,	"DCA Remote Lan Network Control Protocol (RLNCP)" },
+    { 0x8049,	"Serial Data Control Protocol (PPP-SDCP)" },
+    { 0x804b,	"SNA over 802.2 Control Protocol" },
+    { 0x804d,	"SNA Control Protocol" },
+    { 0x804f,	"IP6 Header Compression Control Protocol" },
+    { 0x006f,	"Stampede Bridging Control Protocol" },
+    { 0x80fb,	"Single Link Compression Control Protocol" },
+    { 0x80fd,	"Compression Control Protocol" },
+    { 0xc021,	"Link Control Protocol" },
+    { 0xc023,	"Password Authentication Protocol" },
+    { 0xc025,	"Link Quality Report" },
+    { 0xc027,	"Shiva Password Authentication Protocol" },
+    { 0xc029,	"CallBack Control Protocol (CBCP)" },
+    { 0xc081,	"Container Control Protocol" },
+    { 0xc223,	"Challenge Handshake Authentication Protocol" },
+    { 0xc281,	"Proprietary Authentication Protocol" },
+    { 0,	NULL },
+};
+
+/*
+ * protocol_name - find a name for a PPP protocol.
+ */
+const char *
+protocol_name(proto)
+    int proto;
+{
+    struct protocol_list *lp;
+
+    for (lp = protocol_list; lp->proto != 0; ++lp)
+	if (proto == lp->proto)
+	    return lp->name;
+    return NULL;
+}
+
+/*
+ * get_input - called when incoming data is available.
+ */
+static void
+get_input()
+{
+    int len, i;
+    u_char *p;
+    u_short protocol;
+    struct protent *protp;
+
+    p = inpacket_buf;	/* point to beginning of packet buffer */
+
+    len = read_packet(inpacket_buf);
+    if (len < 0)
+	return;
+
+    if (len == 0) {
+	notice("Modem hangup");
+	hungup = 1;
+	status = EXIT_HANGUP;
+	lcp_lowerdown(0);	/* serial link is no longer available */
+	link_terminated(0);
+	return;
+    }
+
+    if (debug /*&& (debugflags & DBG_INPACKET)*/)
+	dbglog("rcvd %P", p, len);
+
+    if (len < PPP_HDRLEN) {
+	MAINDEBUG(("io(): Received short packet."));
+	return;
+    }
+
+    p += 2;				/* Skip address and control */
+    GETSHORT(protocol, p);
+    len -= PPP_HDRLEN;
+
+    /*
+     * Toss all non-LCP packets unless LCP is OPEN.
+     */
+    if (protocol != PPP_LCP && lcp_fsm[0].state != OPENED) {
+	MAINDEBUG(("get_input: Received non-LCP packet when LCP not open."));
+	return;
+    }
+
+    /*
+     * Until we get past the authentication phase, toss all packets
+     * except LCP, LQR and authentication packets.
+     */
+    if (phase <= PHASE_AUTHENTICATE
+	&& !(protocol == PPP_LCP || protocol == PPP_LQR
+	     || protocol == PPP_PAP || protocol == PPP_CHAP)) {
+	MAINDEBUG(("get_input: discarding proto 0x%x in phase %d",
+		   protocol, phase));
+	return;
+    }
+
+    /*
+     * Upcall the proper protocol input routine.
+     */
+    for (i = 0; (protp = protocols[i]) != NULL; ++i) {
+	if (protp->protocol == protocol && protp->enabled_flag) {
+	    (*protp->input)(0, p, len);
+	    return;
+	}
+        if (protocol == (protp->protocol & ~0x8000) && protp->enabled_flag
+	    && protp->datainput != NULL) {
+	    (*protp->datainput)(0, p, len);
+	    return;
+	}
+    }
+
+    if (debug) {
+	const char *pname = protocol_name(protocol);
+	if (pname != NULL)
+	    warn("Unsupported protocol '%s' (0x%x) received", pname, protocol);
+	else
+	    warn("Unsupported protocol 0x%x received", protocol);
+    }
+    lcp_sprotrej(0, p - PPP_HDRLEN, len + PPP_HDRLEN);
+}
+
+/*
+ * new_phase - signal the start of a new phase of pppd's operation.
+ */
+void
+new_phase(p)
+    int p;
+{
+    phase = p;
+    if (new_phase_hook)
+	(*new_phase_hook)(p);
+    notify(phasechange, p);
+}
+
+/*
+ * die - clean up state and exit with the specified status.
+ */
+void
+die(status)
+    int status;
+{
+    cleanup();
+    notify(exitnotify, status);
+    syslog(LOG_INFO, "Exit.");
+    exit(status);
+}
+
+/*
+ * cleanup - restore anything which needs to be restored before we exit
+ */
+/* ARGSUSED */
+static void
+cleanup()
+{
+    sys_cleanup();
+
+    if (fd_ppp >= 0)
+	the_channel->disestablish_ppp(devfd);
+    if (the_channel->cleanup)
+	(*the_channel->cleanup)();
+
+    if (pidfilename[0] != 0 && unlink(pidfilename) < 0 && errno != ENOENT) 
+	warn("unable to delete pid file %s: %m", pidfilename);
+    pidfilename[0] = 0;
+    if (linkpidfile[0] != 0 && unlink(linkpidfile) < 0 && errno != ENOENT) 
+	warn("unable to delete pid file %s: %m", linkpidfile);
+    linkpidfile[0] = 0;
+
+    if (pppdb != NULL)
+	cleanup_db();
+}
+
+/*
+ * update_link_stats - get stats at link termination.
+ */
+void
+update_link_stats(u)
+    int u;
+{
+    struct timeval now;
+    char numbuf[32];
+
+    if (!get_ppp_stats(u, &link_stats)
+	|| gettimeofday(&now, NULL) < 0)
+	return;
+    link_connect_time = now.tv_sec - start_time.tv_sec;
+    link_stats_valid = 1;
+
+    slprintf(numbuf, sizeof(numbuf), "%d", link_connect_time);
+    script_setenv("CONNECT_TIME", numbuf, 0);
+    slprintf(numbuf, sizeof(numbuf), "%d", link_stats.bytes_out);
+    script_setenv("BYTES_SENT", numbuf, 0);
+    slprintf(numbuf, sizeof(numbuf), "%d", link_stats.bytes_in);
+    script_setenv("BYTES_RCVD", numbuf, 0);
+}
+
+
+struct	callout {
+    struct timeval	c_time;		/* time at which to call routine */
+    void		*c_arg;		/* argument to routine */
+    void		(*c_func) __P((void *)); /* routine */
+    struct		callout *c_next;
+};
+
+static struct callout *callout = NULL;	/* Callout list */
+static struct timeval timenow;		/* Current time */
+
+/*
+ * timeout - Schedule a timeout.
+ *
+ * Note that this timeout takes the number of milliseconds, NOT hz (as in
+ * the kernel).
+ */
+void
+timeout(func, arg, secs, usecs)
+    void (*func) __P((void *));
+    void *arg;
+    int secs, usecs;
+{
+    struct callout *newp, *p, **pp;
+  
+    MAINDEBUG(("Timeout %p:%p in %d.%03d seconds.", func, arg,
+	       time / 1000, time % 1000));
+  
+    /*
+     * Allocate timeout.
+     */
+    if ((newp = (struct callout *) malloc(sizeof(struct callout))) == NULL)
+	fatal("Out of memory in timeout()!");
+    newp->c_arg = arg;
+    newp->c_func = func;
+    gettimeofday(&timenow, NULL);
+    newp->c_time.tv_sec = timenow.tv_sec + secs;
+    newp->c_time.tv_usec = timenow.tv_usec + usecs;
+    if (newp->c_time.tv_usec >= 1000000) {
+	newp->c_time.tv_sec += newp->c_time.tv_usec / 1000000;
+	newp->c_time.tv_usec %= 1000000;
+    }
+
+    /*
+     * Find correct place and link it in.
+     */
+    for (pp = &callout; (p = *pp); pp = &p->c_next)
+	if (newp->c_time.tv_sec < p->c_time.tv_sec
+	    || (newp->c_time.tv_sec == p->c_time.tv_sec
+		&& newp->c_time.tv_usec < p->c_time.tv_usec))
+	    break;
+    newp->c_next = p;
+    *pp = newp;
+}
+
+
+/*
+ * untimeout - Unschedule a timeout.
+ */
+void
+untimeout(func, arg)
+    void (*func) __P((void *));
+    void *arg;
+{
+    struct callout **copp, *freep;
+  
+    MAINDEBUG(("Untimeout %p:%p.", func, arg));
+  
+    /*
+     * Find first matching timeout and remove it from the list.
+     */
+    for (copp = &callout; (freep = *copp); copp = &freep->c_next)
+	if (freep->c_func == func && freep->c_arg == arg) {
+	    *copp = freep->c_next;
+	    free((char *) freep);
+	    break;
+	}
+}
+
+
+/*
+ * calltimeout - Call any timeout routines which are now due.
+ */
+static void
+calltimeout()
+{
+    struct callout *p;
+
+    while (callout != NULL) {
+	p = callout;
+
+	if (gettimeofday(&timenow, NULL) < 0)
+	    fatal("Failed to get time of day: %m");
+	if (!(p->c_time.tv_sec < timenow.tv_sec
+	      || (p->c_time.tv_sec == timenow.tv_sec
+		  && p->c_time.tv_usec <= timenow.tv_usec)))
+	    break;		/* no, it's not time yet */
+
+	callout = p->c_next;
+	(*p->c_func)(p->c_arg);
+
+	free((char *) p);
+    }
+}
+
+
+/*
+ * timeleft - return the length of time until the next timeout is due.
+ */
+static struct timeval *
+timeleft(tvp)
+    struct timeval *tvp;
+{
+    if (callout == NULL)
+	return NULL;
+
+    gettimeofday(&timenow, NULL);
+    tvp->tv_sec = callout->c_time.tv_sec - timenow.tv_sec;
+    tvp->tv_usec = callout->c_time.tv_usec - timenow.tv_usec;
+    if (tvp->tv_usec < 0) {
+	tvp->tv_usec += 1000000;
+	tvp->tv_sec -= 1;
+    }
+    if (tvp->tv_sec < 0)
+	tvp->tv_sec = tvp->tv_usec = 0;
+
+    return tvp;
+}
+
+
+/*
+ * kill_my_pg - send a signal to our process group, and ignore it ourselves.
+ */
+static void
+kill_my_pg(sig)
+    int sig;
+{
+    struct sigaction act, oldact;
+
+    act.sa_handler = SIG_IGN;
+    act.sa_flags = 0;
+    kill(0, sig);
+    sigaction(sig, &act, &oldact);
+    sigaction(sig, &oldact, NULL);
+}
+
+
+/*
+ * hup - Catch SIGHUP signal.
+ *
+ * Indicates that the physical layer has been disconnected.
+ * We don't rely on this indication; if the user has sent this
+ * signal, we just take the link down.
+ */
+static void
+hup(sig)
+    int sig;
+{
+    info("Hangup (SIGHUP)");
+    got_sighup = 1;
+    if (conn_running)
+	/* Send the signal to the [dis]connector process(es) also */
+	kill_my_pg(sig);
+    notify(sigreceived, sig);
+    if (waiting)
+	siglongjmp(sigjmp, 1);
+}
+
+
+/*
+ * term - Catch SIGTERM signal and SIGINT signal (^C/del).
+ *
+ * Indicates that we should initiate a graceful disconnect and exit.
+ */
+/*ARGSUSED*/
+static void
+term(sig)
+    int sig;
+{
+    info("Terminating on signal %d.", sig);
+    got_sigterm = 1;
+    if (conn_running)
+	/* Send the signal to the [dis]connector process(es) also */
+	kill_my_pg(sig);
+    notify(sigreceived, sig);
+    if (waiting)
+	siglongjmp(sigjmp, 1);
+}
+
+
+/*
+ * chld - Catch SIGCHLD signal.
+ * Sets a flag so we will call reap_kids in the mainline.
+ */
+static void
+chld(sig)
+    int sig;
+{
+    got_sigchld = 1;
+    if (waiting)
+	siglongjmp(sigjmp, 1);
+}
+
+
+/*
+ * toggle_debug - Catch SIGUSR1 signal.
+ *
+ * Toggle debug flag.
+ */
+/*ARGSUSED*/
+static void
+toggle_debug(sig)
+    int sig;
+{
+    debug = !debug;
+    if (debug) {
+	setlogmask(LOG_UPTO(LOG_DEBUG));
+    } else {
+	setlogmask(LOG_UPTO(LOG_WARNING));
+    }
+}
+
+
+/*
+ * open_ccp - Catch SIGUSR2 signal.
+ *
+ * Try to (re)negotiate compression.
+ */
+/*ARGSUSED*/
+static void
+open_ccp(sig)
+    int sig;
+{
+    got_sigusr2 = 1;
+    if (waiting)
+	siglongjmp(sigjmp, 1);
+}
+
+
+/*
+ * bad_signal - We've caught a fatal signal.  Clean up state and exit.
+ */
+static void
+bad_signal(sig)
+    int sig;
+{
+    static int crashed = 0;
+
+    if (crashed)
+	_exit(127);
+    crashed = 1;
+    error("Fatal signal %d", sig);
+    if (conn_running)
+	kill_my_pg(SIGTERM);
+    notify(sigreceived, sig);
+    die(127);
+}
+
+
+/*
+ * device_script - run a program to talk to the specified fds
+ * (e.g. to run the connector or disconnector script).
+ * stderr gets connected to the log fd or to the _PATH_CONNERRS file.
+ */
+int
+device_script(program, in, out, dont_wait)
+    char *program;
+    int in, out;
+    int dont_wait;
+{
+    int pid, fd;
+    int status = -1;
+    int errfd;
+
+    ++conn_running;
+    pid = fork();
+
+    if (pid < 0) {
+	--conn_running;
+	error("Failed to create child process: %m");
+	return -1;
+    }
+
+    if (pid != 0) {
+	if (dont_wait) {
+	    record_child(pid, program, NULL, NULL);
+	    status = 0;
+	} else {
+	    while (waitpid(pid, &status, 0) < 0) {
+		if (errno == EINTR)
+		    continue;
+		fatal("error waiting for (dis)connection process: %m");
+	    }
+	    --conn_running;
+	}
+	return (status == 0 ? 0 : -1);
+    }
+
+    /* here we are executing in the child */
+    /* make sure fds 0, 1, 2 are occupied */
+    while ((fd = dup(in)) >= 0) {
+	if (fd > 2) {
+	    close(fd);
+	    break;
+	}
+    }
+
+    /* dup in and out to fds > 2 */
+    in = dup(in);
+    out = dup(out);
+    if (log_to_fd >= 0) {
+	errfd = dup(log_to_fd);
+    } else {
+	errfd = open(_PATH_CONNERRS, O_WRONLY | O_APPEND | O_CREAT, 0600);
+    }
+
+    /* close fds 0 - 2 and any others we can think of */
+    close(0);
+    close(1);
+    close(2);
+    sys_close();
+    if (the_channel->close)
+	(*the_channel->close)();
+    closelog();
+
+    /* dup the in, out, err fds to 0, 1, 2 */
+    dup2(in, 0);
+    close(in);
+    dup2(out, 1);
+    close(out);
+    if (errfd >= 0) {
+	dup2(errfd, 2);
+	close(errfd);
+    }
+
+    setuid(uid);
+    if (getuid() != uid) {
+	error("setuid failed");
+	exit(1);
+    }
+    setgid(getgid());
+    execl("/bin/sh", "sh", "-c", program, (char *)0);
+    error("could not exec /bin/sh: %m");
+    exit(99);
+    /* NOTREACHED */
+}
+
+
+/*
+ * run-program - execute a program with given arguments,
+ * but don't wait for it.
+ * If the program can't be executed, logs an error unless
+ * must_exist is 0 and the program file doesn't exist.
+ * Returns -1 if it couldn't fork, 0 if the file doesn't exist
+ * or isn't an executable plain file, or the process ID of the child.
+ * If done != NULL, (*done)(arg) will be called later (within
+ * reap_kids) iff the return value is > 0.
+ */
+pid_t
+run_program(prog, args, must_exist, done, arg)
+    char *prog;
+    char **args;
+    int must_exist;
+    void (*done) __P((void *));
+    void *arg;
+{
+    int pid;
+    struct stat sbuf;
+
+    /*
+     * First check if the file exists and is executable.
+     * We don't use access() because that would use the
+     * real user-id, which might not be root, and the script
+     * might be accessible only to root.
+     */
+    errno = EINVAL;
+    if (stat(prog, &sbuf) < 0 || !S_ISREG(sbuf.st_mode)
+	|| (sbuf.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0) {
+	if (must_exist || errno != ENOENT)
+	    warn("Can't execute %s: %m", prog);
+	return 0;
+    }
+
+    pid = fork();
+    if (pid == -1) {
+	error("Failed to create child process for %s: %m", prog);
+	return -1;
+    }
+    if (pid == 0) {
+	int new_fd;
+
+	/* Leave the current location */
+	(void) setsid();	/* No controlling tty. */
+	(void) umask (S_IRWXG|S_IRWXO);
+	(void) chdir ("/");	/* no current directory. */
+	setuid(0);		/* set real UID = root */
+	setgid(getegid());
+
+	/* Ensure that nothing of our device environment is inherited. */
+	sys_close();
+	closelog();
+	close (0);
+	close (1);
+	close (2);
+	if (the_channel->close)
+	    (*the_channel->close)();
+
+        /* Don't pass handles to the PPP device, even by accident. */
+	new_fd = open (_PATH_DEVNULL, O_RDWR);
+	if (new_fd >= 0) {
+	    if (new_fd != 0) {
+	        dup2  (new_fd, 0); /* stdin <- /dev/null */
+		close (new_fd);
+	    }
+	    dup2 (0, 1); /* stdout -> /dev/null */
+	    dup2 (0, 2); /* stderr -> /dev/null */
+	}
+
+#ifdef BSD
+	/* Force the priority back to zero if pppd is running higher. */
+	if (setpriority (PRIO_PROCESS, 0, 0) < 0)
+	    warn("can't reset priority to 0: %m"); 
+#endif
+
+	/* SysV recommends a second fork at this point. */
+
+	/* run the program */
+	execve(prog, args, script_env);
+	if (must_exist || errno != ENOENT) {
+	    /* have to reopen the log, there's nowhere else
+	       for the message to go. */
+	    reopen_log();
+	    syslog(LOG_ERR, "Can't execute %s: %m", prog);
+	    closelog();
+	}
+	_exit(-1);
+    }
+
+    if (debug)
+	dbglog("Script %s started (pid %d)", prog, pid);
+    record_child(pid, prog, done, arg);
+
+    return pid;
+}
+
+
+/*
+ * record_child - add a child process to the list for reap_kids
+ * to use.
+ */
+void
+record_child(pid, prog, done, arg)
+    int pid;
+    char *prog;
+    void (*done) __P((void *));
+    void *arg;
+{
+    struct subprocess *chp;
+
+    ++n_children;
+
+    chp = (struct subprocess *) malloc(sizeof(struct subprocess));
+    if (chp == NULL) {
+	warn("losing track of %s process", prog);
+    } else {
+	chp->pid = pid;
+	chp->prog = prog;
+	chp->done = done;
+	chp->arg = arg;
+	chp->next = children;
+	children = chp;
+    }
+}
+
+
+/*
+ * reap_kids - get status from any dead child processes,
+ * and log a message for abnormal terminations.
+ */
+static int
+reap_kids(waitfor)
+    int waitfor;
+{
+    int pid, status;
+    struct subprocess *chp, **prevp;
+
+    if (n_children == 0)
+	return 0;
+    while ((pid = waitpid(-1, &status, (waitfor? 0: WNOHANG))) != -1
+	   && pid != 0) {
+	for (prevp = &children; (chp = *prevp) != NULL; prevp = &chp->next) {
+	    if (chp->pid == pid) {
+		--n_children;
+		*prevp = chp->next;
+		break;
+	    }
+	}
+	if (WIFSIGNALED(status)) {
+	    warn("Child process %s (pid %d) terminated with signal %d",
+		 (chp? chp->prog: "??"), pid, WTERMSIG(status));
+	} else if (debug)
+	    dbglog("Script %s finished (pid %d), status = 0x%x",
+		   (chp? chp->prog: "??"), pid, status);
+	if (chp && chp->done)
+	    (*chp->done)(chp->arg);
+	if (chp)
+	    free(chp);
+    }
+    if (pid == -1) {
+	if (errno == ECHILD)
+	    return -1;
+	if (errno != EINTR)
+	    error("Error waiting for child process: %m");
+    }
+    return 0;
+}
+
+/*
+ * add_notifier - add a new function to be called when something happens.
+ */
+void
+add_notifier(notif, func, arg)
+    struct notifier **notif;
+    notify_func func;
+    void *arg;
+{
+    struct notifier *np;
+
+    np = malloc(sizeof(struct notifier));
+    if (np == 0)
+	novm("notifier struct");
+    np->next = *notif;
+    np->func = func;
+    np->arg = arg;
+    *notif = np;
+}
+
+/*
+ * remove_notifier - remove a function from the list of things to
+ * be called when something happens.
+ */
+void
+remove_notifier(notif, func, arg)
+    struct notifier **notif;
+    notify_func func;
+    void *arg;
+{
+    struct notifier *np;
+
+    for (; (np = *notif) != 0; notif = &np->next) {
+	if (np->func == func && np->arg == arg) {
+	    *notif = np->next;
+	    free(np);
+	    break;
+	}
+    }
+}
+
+/*
+ * notify - call a set of functions registered with add_notify.
+ */
+void
+notify(notif, val)
+    struct notifier *notif;
+    int val;
+{
+    struct notifier *np;
+
+    while ((np = notif) != 0) {
+	notif = np->next;
+	(*np->func)(np->arg, val);
+    }
+}
+
+/*
+ * novm - log an error message saying we ran out of memory, and die.
+ */
+void
+novm(msg)
+    char *msg;
+{
+    fatal("Virtual memory exhausted allocating %s\n", msg);
+}
+
+/*
+ * script_setenv - set an environment variable value to be used
+ * for scripts that we run (e.g. ip-up, auth-up, etc.)
+ */
+void
+script_setenv(var, value, iskey)
+    char *var, *value;
+    int iskey;
+{
+    size_t varl = strlen(var);
+    size_t vl = varl + strlen(value) + 2;
+    int i;
+    char *p, *newstring;
+
+    newstring = (char *) malloc(vl+1);
+    if (newstring == 0)
+	return;
+    *newstring++ = iskey;
+    slprintf(newstring, vl, "%s=%s", var, value);
+
+    /* check if this variable is already set */
+    if (script_env != 0) {
+	for (i = 0; (p = script_env[i]) != 0; ++i) {
+	    if (strncmp(p, var, varl) == 0 && p[varl] == '=') {
+		if (p[-1] && pppdb != NULL)
+		    delete_db_key(p);
+		free(p-1);
+		script_env[i] = newstring;
+		if (iskey && pppdb != NULL)
+		    add_db_key(newstring);
+		update_db_entry();
+		return;
+	    }
+	}
+    } else {
+	/* no space allocated for script env. ptrs. yet */
+	i = 0;
+	script_env = (char **) malloc(16 * sizeof(char *));
+	if (script_env == 0)
+	    return;
+	s_env_nalloc = 16;
+    }
+
+    /* reallocate script_env with more space if needed */
+    if (i + 1 >= s_env_nalloc) {
+	int new_n = i + 17;
+	char **newenv = (char **) realloc((void *)script_env,
+					  new_n * sizeof(char *));
+	if (newenv == 0)
+	    return;
+	script_env = newenv;
+	s_env_nalloc = new_n;
+    }
+
+    script_env[i] = newstring;
+    script_env[i+1] = 0;
+
+    if (pppdb != NULL) {
+	if (iskey)
+	    add_db_key(newstring);
+	update_db_entry();
+    }
+}
+
+/*
+ * script_unsetenv - remove a variable from the environment
+ * for scripts.
+ */
+void
+script_unsetenv(var)
+    char *var;
+{
+    int vl = strlen(var);
+    int i;
+    char *p;
+
+    if (script_env == 0)
+	return;
+    for (i = 0; (p = script_env[i]) != 0; ++i) {
+	if (strncmp(p, var, vl) == 0 && p[vl] == '=') {
+	    if (p[-1] && pppdb != NULL)
+		delete_db_key(p);
+	    free(p-1);
+	    while ((script_env[i] = script_env[i+1]) != 0)
+		++i;
+	    break;
+	}
+    }
+    if (pppdb != NULL)
+	update_db_entry();
+}
+
+/*
+ * update_db_entry - update our entry in the database.
+ */
+static void
+update_db_entry()
+{
+    TDB_DATA key, dbuf;
+    int vlen, i;
+    char *p, *q, *vbuf;
+
+    if (script_env == NULL)
+	return;
+    vlen = 0;
+    for (i = 0; (p = script_env[i]) != 0; ++i)
+	vlen += strlen(p) + 1;
+    vbuf = malloc(vlen);
+    if (vbuf == 0)
+	novm("database entry");
+    q = vbuf;
+    for (i = 0; (p = script_env[i]) != 0; ++i)
+	q += slprintf(q, vbuf + vlen - q, "%s;", p);
+
+    key.dptr = db_key;
+    key.dsize = strlen(db_key);
+    dbuf.dptr = vbuf;
+    dbuf.dsize = vlen;
+    if (tdb_store(pppdb, key, dbuf, TDB_REPLACE))
+	error("tdb_store failed: %s", tdb_error(pppdb));
+
+}
+
+/*
+ * add_db_key - add a key that we can use to look up our database entry.
+ */
+static void
+add_db_key(str)
+    const char *str;
+{
+    TDB_DATA key, dbuf;
+
+    key.dptr = (char *) str;
+    key.dsize = strlen(str);
+    dbuf.dptr = db_key;
+    dbuf.dsize = strlen(db_key);
+    if (tdb_store(pppdb, key, dbuf, TDB_REPLACE))
+	error("tdb_store key failed: %s", tdb_error(pppdb));
+}
+
+/*
+ * delete_db_key - delete a key for looking up our database entry.
+ */
+static void
+delete_db_key(str)
+    const char *str;
+{
+    TDB_DATA key;
+
+    key.dptr = (char *) str;
+    key.dsize = strlen(str);
+    tdb_delete(pppdb, key);
+}
+
+/*
+ * cleanup_db - delete all the entries we put in the database.
+ */
+static void
+cleanup_db()
+{
+    TDB_DATA key;
+    int i;
+    char *p;
+
+    key.dptr = db_key;
+    key.dsize = strlen(db_key);
+    tdb_delete(pppdb, key);
+    for (i = 0; (p = script_env[i]) != 0; ++i)
+	if (p[-1])
+	    delete_db_key(p);
+}