main.c

自己精简过的PPPD代码。在嵌入中应用可以更好的发挥。比原先的小了很多

/*
 * main.c - Point-to-Point Protocol main module
 *
 * Copyright (c) 1984-2000 Carnegie Mellon University. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The name "Carnegie Mellon University" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For permission or any legal
 *    details, please contact
 *      Office of Technology Transfer
 *      Carnegie Mellon University
 *      5000 Forbes Avenue
 *      Pittsburgh, PA  15213-3890
 *      [phone], fax: [phone]
 *      [e-mail]
 *
 * 4. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by Computing Services
 *     at Carnegie Mellon University (http://www.cmu.edu/computing/)."
 *
 * CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
 * FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * Copyright (c) 1999-2004 Paul Mackerras. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. The name(s) of the authors of this software must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission.
 *
 * 3. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by Paul Mackerras
 *     <[e-mail]>".
 *
 * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#define RCSID	"$Id: main.c,v 1.153 2006/06/04 03:52:50 paulus Exp $"

#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-new.h"
#include "eap.h"
#include "ccp.h"
#include "ecp.h"
#include "pathnames.h"

#ifdef USE_TDB
#include "tdb.h"
#endif

#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;
struct notifier *fork_notifier = 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 */
int ppp_session_number;		/* Session number, for channels with such a
				   concept (eg PPPoE) */
int childwait_done;		/* have timed out waiting for children */

#ifdef USE_TDB
TDB_CONTEXT *pppdb;		/* database for storing status etc. */
#endif

char db_key[32];

int (*holdoff_hook) __P((void)) = NULL;
int (*new_phase_hook) __P((int)) = NULL;
void (*snoop_recv_hook) __P((unsigned char *p, int len)) = NULL;
void (*snoop_send_hook) __P((unsigned char *p, int len)) = NULL;

static int conn_running;	/* we have a [dis]connector running */
static int fd_loop;		/* fd for getting demand-dial packets */

int fd_devnull;			/* fd for /dev/null */
int devfd = -1;			/* fd of underlying device */
int fd_ppp = -1;		/* fd for talking PPP */
int phase;			/* where the link is at */
int kill_link;
int asked_to_quit;
int open_ccp_flag;
int listen_time;
int got_sigusr2;
int got_sigterm;
int got_sighup;

static sigset_t signals_handled;
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. */

static struct pppd_stats old_link_stats;
struct pppd_stats link_stats;
unsigned link_connect_time;
int link_stats_valid;

int error_count;

bool bundle_eof;
bool bundle_terminating;

/*
 * 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((int pid));
static void create_linkpidfile __P((int pid));
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 void forget_child __P((int pid, int status));
static int reap_kids __P((void));
static void childwait_end __P((void *));

#ifdef USE_TDB
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));
#endif

static void handle_events __P((void));
void print_link_stats __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,
    //&ecp_protent,
#ifdef IPX_CHANGE
    &ipxcp_protent,
#endif
#ifdef AT_CHANGE
    &atcp_protent,
#endif
    //&eap_protent,
    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];

    link_stats_valid = 0;
    new_phase(PHASE_INITIALIZE);

    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);*/
	
	strncpy(user,argv[4],MAXNAMELEN);
	strncpy(passwd,argv[6],MAXSECRETLEN);
	ptycommand = malloc(strlen(argv[2]));
	strncpy(ptycommand,argv[2],strlen(argv[2]));
    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);

    /* Make sure fds 0, 1, 2 are open to somewhere. */
    fd_devnull = open(_PATH_DEVNULL, O_RDWR);
    if (fd_devnull < 0)
	fatal("Couldn't open %s: %m", _PATH_DEVNULL);
    while (fd_devnull <= 2) {
	i = dup(fd_devnull);
	if (i < 0)
	    fatal("Critical shortage of file descriptors: dup failed: %m");
	fd_devnull = i;
    }

    /*
     * Initialize system-dependent stuff.
     */
    sys_init();

#ifdef USE_TDB
    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;
	}
    }
#endif

    /*
     * 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();

    create_linkpidfile(getpid());

    waiting = 0;

    /*
     * 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.
	 */
	fd_loop = open_ppp_loopback();
	set_ifunit(1);
	/*
	 * Configure the interface and mark it up, etc.
	 */
	demand_conf();
    }

    do_callback = 0;
    for (;;) {

	bundle_eof = 0;
	bundle_terminating = 0;
	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 (asked_to_quit)
		    break;
		if (get_loop_output())
		    break;
	    }
	    remove_fd(fd_loop);
	    if (asked_to_quit)
		break;

	    /*
	     * Now we want to bring up the link.
	     */
	    demand_block();
	    info("Starting link");
	}