/*
 * Copyright (c) 1995
 *      Bill Paul <wpaul@ctr.columbia.edu>.  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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Bill Paul.
 * 4. Neither the name of the author nor the names of any co-contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL Bill Paul OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD: src/usr.sbin/ypserv/yp_main.c,v 1.29 2008/02/03 17:39:37 matteo Exp $
 */

/*
 * ypserv startup function.
 * We need out own main() since we have to do some additional work
 * that rpcgen won't do for us. Most of this file was generated using
 * rpcgen.new, and later modified.
 */

#include "yp.h"
#include <err.h>
#include <errno.h>
#include <memory.h>
#include <stdio.h>
#include <signal.h>
#include <stdlib.h> /* getenv, exit */
#include <string.h> /* strcmp */
#include <syslog.h>
#include <unistd.h>
#include <rpc/pmap_clnt.h> /* for pmap_unset */
#ifdef __cplusplus
#include <sysent.h> /* getdtablesize, open */
#endif /* __cplusplus */
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/wait.h>
#include "yp_extern.h"
#include <rpc/rpc.h>

#ifndef SIG_PF
#define SIG_PF void(*)(int)
#endif

#define _RPCSVC_CLOSEDOWN 120
int _rpcpmstart;                /* Started by a port monitor ? */
static int _rpcfdtype;
                 /* Whether Stream or Datagram ? */
        /* States a server can be in wrt request */

#define _IDLE 0
#define _SERVED 1
#define _SERVING 2

extern void ypprog_1(struct svc_req *, SVCXPRT *);
extern void ypprog_2(struct svc_req *, SVCXPRT *);
extern int _rpc_dtablesize(void);
extern int _rpcsvcstate;         /* Set when a request is serviced */
char *progname = "ypserv";
const char *yp_dir = _PATH_YP;
int debug = 0;
int do_dns = 0;
int resfd;

struct socktype {
        const char *st_name;
        int        st_type;
};
static struct socktype stlist[] = {
        { "tcp", SOCK_STREAM },
        { "udp", SOCK_DGRAM },
        { NULL, 0 }
};

static void
_msgout(char *msg)
{
        if (debug) {
                if (_rpcpmstart)
                        syslog(LOG_ERR, "%s", msg);
                else
                        warnx("%s", msg);
        } else
                syslog(LOG_ERR, "%s", msg);
}

pid_t   yp_pid;

static void
yp_svc_run(void)
{
#ifdef FD_SETSIZE
        fd_set readfds;
#else
        int readfds;
#endif /* def FD_SETSIZE */
        int fd_setsize = _rpc_dtablesize();
        struct timeval timeout;

        /* Establish the identity of the parent ypserv process. */
        yp_pid = getpid();

        for (;;) {
#ifdef FD_SETSIZE
                readfds = svc_fdset;
#else
                readfds = svc_fds;
#endif /* def FD_SETSIZE */

                FD_SET(resfd, &readfds);

                timeout.tv_sec = RESOLVER_TIMEOUT;
                timeout.tv_usec = 0;
                switch (select(fd_setsize, &readfds, NULL, NULL,
                               &timeout)) {
                case -1:
                        if (errno == EINTR) {
                                continue;
                        }
                        warn("svc_run: - select failed");
                        return;
                case 0:
                        if (getpid() == yp_pid)
                                yp_prune_dnsq();
                        break;
                default:
                        if (getpid() == yp_pid) {
                                if (FD_ISSET(resfd, &readfds)) {
                                        yp_run_dnsq();
                                        FD_CLR(resfd, &readfds);
                                }
                                svc_getreqset(&readfds);
                        }
                }
                if (yp_pid != getpid())
                        _exit(0);
        }
}

static void
unregister(void)
{
        pmap_unset(YPPROG, YPVERS);
        pmap_unset(YPPROG, YPOLDVERS);
}

static void
reaper(int sig)
{
        int status;
        int saved_errno;

        saved_errno = errno;

        if (sig == SIGHUP) {
                load_securenets();
#ifdef DB_CACHE
                yp_flush_all();
#endif
                errno = saved_errno;
                return;
        }

        if (sig == SIGCHLD) {
                while (wait3(&status, WNOHANG, NULL) > 0)
                        children--;
        } else {
                unregister();
                exit(0);
        }
        errno = saved_errno;
        return;
}

static void
usage(void)
{
        fprintf(stderr, "usage: ypserv [-h] [-d] [-n] [-p path] [-P port]\n");
        exit(1);
}

static void
closedown(int sig)
{
        if (_rpcsvcstate == _IDLE) {
                extern fd_set svc_fdset;
                static int size;
                int i, openfd;

                if (_rpcfdtype == SOCK_DGRAM) {
                        unregister();
                        exit(0);
                }
                if (size == 0) {
                        size = getdtablesize();
                }
                for (i = 0, openfd = 0; i < size && openfd < 2; i++)
                        if (FD_ISSET(i, &svc_fdset))
                                openfd++;
                if (openfd <= 1) {
                        unregister();
                        exit(0);
                }
        }
        if (_rpcsvcstate == _SERVED)
                _rpcsvcstate = _IDLE;

        signal(SIGALRM, (SIG_PF)closedown);
        alarm(_RPCSVC_CLOSEDOWN / 2);
}

int
main(int argc, char *argv[])
{
        SVCXPRT *transp = NULL;
        int sock;
        int proto = 0;
        struct sockaddr_in saddr;
        socklen_t asize = sizeof (saddr);
        int ch;
        in_port_t yp_port = 0;
        char *errstr;
        struct socktype *st;

        while ((ch = getopt(argc, argv, "hdnp:P:")) != -1) {
                switch (ch) {
                case 'd':
                        debug = ypdb_debug = 1;
                        break;
                case 'n':
                        do_dns = 1;
                        break;
                case 'p':
                        yp_dir = optarg;
                        break;
                case 'P':
                        yp_port = (in_port_t)strtonum(optarg, 1, 65535,
                            (const char **)&errstr);
                        if (yp_port == 0 && errstr != NULL) {
                                _msgout("invalid port number provided");
                                exit(1);
                        }
                        break;
                case 'h':
                default:
                        usage();
                }
        }

        load_securenets();
        yp_init_resolver();
#ifdef DB_CACHE
        yp_init_dbs();
#endif
        if (getsockname(0, (struct sockaddr *)&saddr, &asize) == 0) {
                int ssize = sizeof (int);

                if (saddr.sin_family != AF_INET)
                        exit(1);
                if (getsockopt(0, SOL_SOCKET, SO_TYPE,
                                (char *)&_rpcfdtype, &ssize) == -1)
                        exit(1);
                sock = 0;
                _rpcpmstart = 1;
                proto = 0;
                openlog("ypserv", LOG_PID, LOG_DAEMON);
        } else {
                if (!debug) {
                        if (daemon(0,0)) {
                                err(1,"cannot fork");
                        }
                        openlog("ypserv", LOG_PID, LOG_DAEMON);
                }
                sock = RPC_ANYSOCK;
                pmap_unset(YPPROG, YPVERS);
                pmap_unset(YPPROG, 1);
        }

        /*
         * Initialize TCP/UDP sockets.
         */
        memset((char *)&saddr, 0, sizeof(saddr));
        saddr.sin_family = AF_INET;
        saddr.sin_addr.s_addr = htonl(INADDR_ANY);
        saddr.sin_port = htons(yp_port);
        for (st = stlist; st->st_name != NULL; st++) {
                /* Do not bind the socket if the user didn't specify a port */
                if (yp_port == 0)
                        break;

                sock = socket(AF_INET, st->st_type, 0);
                if (sock == -1) {
                        if ((asprintf(&errstr, "cannot create a %s socket",
                            st->st_name)) == -1)
                                err(1, "unexpected failure in asprintf()");
                        _msgout(errstr);
                        free((void *)errstr);
                        exit(1);
                }
                if (bind(sock, (struct sockaddr *) &saddr, sizeof(saddr))
                    == -1) {
                        if ((asprintf(&errstr, "cannot bind %s socket",
                            st->st_name)) == -1)
                                err(1, "unexpected failure in asprintf()");
                        _msgout(errstr);
                        free((void *)errstr);
                        exit(1);
                }
                errstr = NULL;
        }

        if ((_rpcfdtype == 0) || (_rpcfdtype == SOCK_DGRAM)) {
                transp = svcudp_create(sock);
                if (transp == NULL) {
                        _msgout("cannot create udp service");
                        exit(1);
                }
                if (!_rpcpmstart)
                        proto = IPPROTO_UDP;
                if (!svc_register(transp, YPPROG, YPOLDVERS, ypprog_1, proto)) {
                        _msgout("unable to register (YPPROG, YPOLDVERS, udp)");
                        exit(1);
                }
                if (!svc_register(transp, YPPROG, YPVERS, ypprog_2, proto)) {
                        _msgout("unable to register (YPPROG, YPVERS, udp)");
                        exit(1);
                }
        }

        if ((_rpcfdtype == 0) || (_rpcfdtype == SOCK_STREAM)) {
                transp = svctcp_create(sock, 0, 0);
                if (transp == NULL) {
                        _msgout("cannot create tcp service");
                        exit(1);
                }
                if (!_rpcpmstart)
                        proto = IPPROTO_TCP;
                if (!svc_register(transp, YPPROG, YPOLDVERS, ypprog_1, proto)) {
                        _msgout("unable to register (YPPROG, YPOLDVERS, tcp)");
                        exit(1);
                }
                if (!svc_register(transp, YPPROG, YPVERS, ypprog_2, proto)) {
                        _msgout("unable to register (YPPROG, YPVERS, tcp)");
                        exit(1);
                }
        }

        if (transp == NULL) {
                _msgout("could not create a handle");
                exit(1);
        }
        if (_rpcpmstart) {
                signal(SIGALRM, (SIG_PF)closedown);
                alarm(_RPCSVC_CLOSEDOWN / 2);
        }
/*
 * Make sure SIGPIPE doesn't blow us away while servicing TCP
 * connections.
 */
        signal(SIGPIPE, SIG_IGN);
        signal(SIGCHLD, (SIG_PF) reaper);
        signal(SIGTERM, (SIG_PF) reaper);
        signal(SIGINT, (SIG_PF) reaper);
        signal(SIGHUP, (SIG_PF) reaper);
        yp_svc_run();
        _msgout("svc_run returned");
        exit(1);
        /* NOTREACHED */
}