/*
 * Copyright (c) 1992, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Rick Macklem at The University of Guelph.
 *
 * 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. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 THE REGENTS 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.
 *
 * @(#) Copyright (c) 1992, 1993, 1994 The Regents of the University of California.  All rights reserved.
 * @(#)mount_nfs.c      8.11 (Berkeley) 5/4/95
 * $FreeBSD: src/sbin/mount_nfs/mount_nfs.c,v 1.36.2.6 2003/05/13 14:45:40 trhodes Exp $
 */

#include <sys/param.h>
#include <sys/mount.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/syslog.h>

#include <rpc/rpc.h>
#include <rpc/pmap_clnt.h>
#include <rpc/pmap_prot.h>

#include <vfs/nfs/rpcv2.h>
#include <vfs/nfs/nfsproto.h>
#include <vfs/nfs/nfs.h>

#include <arpa/inet.h>

#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <mntopts.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>

#include "mounttab.h"

#define ALTF_BG         0x1
#define ALTF_NOCONN     0x2
#define ALTF_DUMBTIMR   0x4
#define ALTF_INTR       0x8
/* 0x10 was for ALTF_KERB */
#define ALTF_NFSV3      0x20
#define ALTF_RDIRPLUS   0x40
#define ALTF_CACHE      0x80
#define ALTF_RESVPORT   0x100
#define ALTF_SEQPACKET  0x200
#define ALTF_UNUSED400  0x400
#define ALTF_SOFT       0x800
#define ALTF_TCP        0x1000
#define ALTF_PORT       0x2000
#define ALTF_NFSV2      0x4000
#define ALTF_ACREGMIN   0x8000
#define ALTF_ACREGMAX   0x10000
#define ALTF_ACDIRMIN   0x20000
#define ALTF_ACDIRMAX   0x40000
#define ALTF_RETRYCNT   0x80000

struct mntopt mopts[] = {
        MOPT_STDOPTS,
        MOPT_FORCE,
        MOPT_UPDATE,
        MOPT_ASYNC,
        { "bg", 0, ALTF_BG, 1 },
        { "conn", 1, ALTF_NOCONN, 1 },
        { "dumbtimer", 0, ALTF_DUMBTIMR, 1 },
        { "intr", 0, ALTF_INTR, 1 },
        { "nfsv3", 0, ALTF_NFSV3, 1 },
        { "rdirplus", 0, ALTF_RDIRPLUS, 1 },
        { "mntudp", 1, ALTF_TCP, 1 },
        { "resvport", 0, ALTF_RESVPORT, 1 },
        { "soft", 0, ALTF_SOFT, 1 },
        { "tcp", 0, ALTF_TCP, 1 },
        { "udp", 1, ALTF_TCP, 1 },
        { "port=", 0, ALTF_PORT, 1 },
        { "nfsv2", 0, ALTF_NFSV2, 1 },
        { "acregmin=", 0, ALTF_ACREGMIN, 1 },
        { "acregmax=", 0, ALTF_ACREGMAX, 1 },
        { "acdirmin=", 0, ALTF_ACDIRMIN, 1 },
        { "acdirmax=", 0, ALTF_ACDIRMAX, 1 },
        { "cache", 0, ALTF_CACHE, 1 },
        { "retrycnt=", 0, ALTF_RETRYCNT, 1 },
        MOPT_NULL
};

struct nfs_args nfsdefargs = {
        NFS_ARGSVERSION,
        NULL,
        sizeof (struct sockaddr_in),
        0,
        0,
        NULL,
        0,
        NFSMNT_RESVPORT,
        NFS_WSIZE,
        NFS_RSIZE,
        NFS_READDIRSIZE,
        10,
        NFS_RETRANS,
        NFS_MAXGRPS,
        NFS_DEFRAHEAD,
        0,
        NFS_DEADTHRESH,
        NULL,
        /* args version 4 */
        NFS_MINATTRTIMO,
        NFS_MAXATTRTIMO,
        NFS_MINDIRATTRTIMO,
        NFS_MAXDIRATTRTIMO,
};

/* Table for af,sotype -> netid conversions. */
struct nc_protos {
        const char *netid;
        int af;
        int sotype;
} nc_protos[] = {
        {"udp",         AF_INET,        SOCK_DGRAM},
        {"tcp",         AF_INET,        SOCK_STREAM},
        {"udp6",        AF_INET6,       SOCK_DGRAM},
        {"tcp6",        AF_INET6,       SOCK_STREAM},
        {NULL,          0,              0}
};

struct nfhret {
        u_long          stat;
        long            vers;
        long            auth;
        long            fhsize;
        u_char          nfh[NFSX_V3FHMAX];
};
#define BGRND   1
#define ISBGRND 2
int retrycnt = -1;
int opflags = 0;
int nfsproto;
char *portspec = NULL;  /* Server nfs port; NULL means look up via rpcbind. */
enum mountmode {
        ANY,
        V2,
        V3
} mountmode = ANY;

/* Return codes for nfs_tryproto. */
enum tryret {
        TRYRET_SUCCESS,
        TRYRET_TIMEOUT,         /* No response received. */
        TRYRET_REMOTEERR,       /* Error received from remote server. */
        TRYRET_LOCALERR         /* Local failure. */
};

#if 0
void    set_rpc_maxgrouplist(int);
#endif
static struct netconfig *getnetconf_cached(const char *);
static const char       *netidbytype(int, int);
static int      getnfsargs(char *, struct nfs_args *);
static void     usage(void) __dead2;
static int      xdr_dir(XDR *, char *);
static int      xdr_fh(XDR *, struct nfhret *);
static enum tryret
                nfs_tryproto(struct nfs_args *, struct addrinfo *,
                             char *, char *, char **);
static enum tryret
                returncode(enum clnt_stat, struct rpc_err *);

/*
 * Used to set mount flags with getmntopts.  Call with dir=TRUE to
 * initialize altflags from the current mount flags.  Call with
 * dir=FALSE to update mount flags with the new value of altflags after
 * the call to getmntopts.
 */
static void
set_flags(int* altflags, int* nfsflags, int dir)
{
#define F2(af, nf)                                      \
        if (dir) {                                      \
                if (*nfsflags & NFSMNT_##nf)            \
                        *altflags |= ALTF_##af;         \
                else                                    \
                        *altflags &= ~ALTF_##af;        \
        } else {                                        \
                if (*altflags & ALTF_##af)              \
                        *nfsflags |= NFSMNT_##nf;       \
                else                                    \
                        *nfsflags &= ~NFSMNT_##nf;      \
        }
#define F(f)    F2(f,f)

        F(NOCONN);
        F(DUMBTIMR);
        F2(INTR, INT);
        F(RDIRPLUS);
        F(RESVPORT);
        F(SOFT);
        F(ACREGMIN);
        F(ACREGMAX);
        F(ACDIRMIN);
        F(ACDIRMAX);
#ifdef NFSMNT_CACHE
        F(CACHE);
#endif
        F(RETRYCNT);

#undef F
#undef F2
}

int
main(int argc, char **argv)
{
        int c;
        struct nfs_args *nfsargsp;
        struct nfs_args nfsargs;
        int mntflags, altflags, num;
        char *name, *p, *spec;
        char mntpath[MAXPATHLEN];
        struct vfsconf vfc;
        int error = 0;

        mntflags = 0;
        altflags = ALTF_TCP | ALTF_RDIRPLUS;
        nfsargs = nfsdefargs;
        nfsargsp = &nfsargs;
        if (altflags & ALTF_TCP) {
                nfsproto = IPPROTO_TCP;
                nfsargsp->sotype = SOCK_STREAM;
        } else {
                nfsproto = IPPROTO_UDP;
                nfsargsp->sotype = SOCK_DGRAM;
        }
        while ((c = getopt(argc, argv,
            "23a:bcdD:g:I:ilNo:PR:r:sTt:w:x:U")) != -1)
                switch (c) {
                case '2':
                        mountmode = V2;
                        break;
                case '3':
                        mountmode = V3;
                        break;
                case 'a':
                        num = strtol(optarg, &p, 10);
                        if (*p || num < 0)
                                errx(1, "illegal -a value -- %s", optarg);
                        nfsargsp->readahead = num;
                        nfsargsp->flags |= NFSMNT_READAHEAD;
                        break;
                case 'b':
                        opflags |= BGRND;
                        break;
                case 'c':
                        nfsargsp->flags |= NFSMNT_NOCONN;
                        break;
                case 'D':
                        num = strtol(optarg, &p, 10);
                        if (*p || num <= 0)
                                errx(1, "illegal -D value -- %s", optarg);
                        nfsargsp->deadthresh = num;
                        nfsargsp->flags |= NFSMNT_DEADTHRESH;
                        break;
                case 'd':
                        nfsargsp->flags |= NFSMNT_DUMBTIMR;
                        break;
#if 0 /* XXXX */
                case 'g':
                        num = strtol(optarg, &p, 10);
                        if (*p || num <= 0)
                                errx(1, "illegal -g value -- %s", optarg);
                        set_rpc_maxgrouplist(num);
                        nfsargsp->maxgrouplist = num;
                        nfsargsp->flags |= NFSMNT_MAXGRPS;
                        break;
#endif
                case 'I':
                        num = strtol(optarg, &p, 10);
                        if (*p || num <= 0)
                                errx(1, "illegal -I value -- %s", optarg);
                        nfsargsp->readdirsize = num;
                        nfsargsp->flags |= NFSMNT_READDIRSIZE;
                        break;
                case 'i':
                        nfsargsp->flags |= NFSMNT_INT;
                        break;
                case 'l':
                        nfsargsp->flags |= NFSMNT_RDIRPLUS;
                        break;
                case 'N':
                        nfsargsp->flags &= ~NFSMNT_RESVPORT;
                        break;
                case 'o':
                        set_flags(&altflags, &nfsargsp->flags, TRUE);
                        altflags |= ALTF_RDIRPLUS;
                        if (nfsproto == IPPROTO_TCP)
                                altflags |= ALTF_TCP;
                        if (mountmode == V2)
                                altflags |= ALTF_NFSV2;
                        else if (mountmode == V3)
                                altflags |= ALTF_NFSV3;
                        getmntopts(optarg, mopts, &mntflags, &altflags);
                        set_flags(&altflags, &nfsargsp->flags, FALSE);
                        /*
                         * Handle altflags which don't map directly to
                         * mount flags.
                         */
                        if(altflags & ALTF_BG)
                                opflags |= BGRND;
                        if (altflags & ALTF_TCP) {
                                nfsproto = IPPROTO_TCP;
                                nfsargsp->sotype = SOCK_STREAM;
                        } else {
                                nfsproto = IPPROTO_UDP;
                                nfsargsp->sotype = SOCK_DGRAM;
                        }
                        if(altflags & ALTF_PORT) {
                                /*
                                 * XXX Converting from a string to an int
                                 * and back again is silly, and we should
                                 * allow /etc/services names.
                                 */
                                asprintf(&portspec, "%d",
                                         atoi(strstr(optarg, "port=") + 5));
                                if (portspec == NULL)
                                        err(1, "asprintf");
                        }
                        mountmode = ANY;
                        if(altflags & ALTF_NFSV2)
                                mountmode = V2;
                        if(altflags & ALTF_NFSV3)
                                mountmode = V3;
                        if(altflags & ALTF_ACREGMIN)
                                nfsargsp->acregmin = atoi(strstr(optarg,
                                    "acregmin=") + 9);
                        if(altflags & ALTF_ACREGMAX)
                                nfsargsp->acregmax = atoi(strstr(optarg,
                                    "acregmax=") + 9);
                        if(altflags & ALTF_ACDIRMIN)
                                nfsargsp->acdirmin = atoi(strstr(optarg,
                                    "acdirmin=") + 9);
                        if(altflags & ALTF_ACDIRMAX)
                                nfsargsp->acdirmax = atoi(strstr(optarg,
                                    "acdirmax=") + 9);
                        if(altflags & ALTF_RETRYCNT) {
                                num = atoi(strstr(optarg, "retrycnt=") + 9);
                                if (num < 0)
                                        errx(1, "illegal -o retrycnt value -- %s", optarg);
                                retrycnt = num;
                        }
                        break;
                case 'P':
                        /* obsolete for NFSMNT_RESVPORT, now default */
                        break;
                case 'R':
                        num = strtol(optarg, &p, 10);
                        if (*p || num < 0)
                                errx(1, "illegal -R value -- %s", optarg);
                        retrycnt = num;
                        break;
                case 'r':
                        num = strtol(optarg, &p, 10);
                        if (*p || num <= 0)
                                errx(1, "illegal -r value -- %s", optarg);
                        nfsargsp->rsize = num;
                        nfsargsp->flags |= NFSMNT_RSIZE;
                        break;
                case 's':
                        nfsargsp->flags |= NFSMNT_SOFT;
                        break;
                case 'T':
                        nfsargsp->sotype = SOCK_STREAM;
                        nfsproto = IPPROTO_TCP;
                        altflags |= ALTF_TCP;
                        break;
                case 't':
                        num = strtol(optarg, &p, 10);
                        if (*p || num <= 0)
                                errx(1, "illegal -t value -- %s", optarg);
                        nfsargsp->timeo = num;
                        nfsargsp->flags |= NFSMNT_TIMEO;
                        break;
                case 'w':
                        num = strtol(optarg, &p, 10);
                        if (*p || num <= 0)
                                errx(1, "illegal -w value -- %s", optarg);
                        nfsargsp->wsize = num;
                        nfsargsp->flags |= NFSMNT_WSIZE;
                        break;
                case 'x':
                        num = strtol(optarg, &p, 10);
                        if (*p || num <= 0)
                                errx(1, "illegal -x value -- %s", optarg);
                        nfsargsp->retrans = num;
                        nfsargsp->flags |= NFSMNT_RETRANS;
                        break;
                case 'U':
                        nfsargsp->sotype = SOCK_DGRAM;
                        nfsproto = IPPROTO_UDP;
                        altflags &= ~ALTF_TCP;
                        break;
                default:
                        usage();
                        break;
                }
        argc -= optind;
        argv += optind;

        if (argc != 2) {
                usage();
                /* NOTREACHED */
        }

        spec = *argv++;
        name = *argv;

        if (retrycnt == -1)
                /* The default is to keep retrying forever. */
                retrycnt = 0;
        if (!getnfsargs(spec, nfsargsp))
                exit(1);

        /* resolve the mountpoint with realpath(3) */
        checkpath(name, mntpath);

        error = getvfsbyname("nfs", &vfc);
        if (error && vfsisloadable("nfs")) {
                if(vfsload("nfs"))
                        err(EX_OSERR, "vfsload(nfs)");
                endvfsent();    /* clear cache */
                error = getvfsbyname("nfs", &vfc);
        }
        if (error)
                errx(EX_OSERR, "nfs filesystem is not available");

        if (mount(vfc.vfc_name, mntpath, mntflags, nfsargsp))
                err(1, "%s", mntpath);
        exit(0);
}

static int
getnfsargs(char *spec, struct nfs_args *nfsargsp)
{
        struct addrinfo hints, *ai_nfs, *ai;
        enum tryret ret;
        int ecode, speclen, remoteerr;
        char *hostp, *delimp, *errstr;
        size_t len;
        static char nam[MNAMELEN + 1];

        if ((delimp = strrchr(spec, ':')) != NULL) {
                hostp = spec;
                spec = delimp + 1;
        } else if ((delimp = strrchr(spec, '@')) != NULL) {
                warnx("path@server syntax is deprecated, use server:path");
                hostp = delimp + 1;
        } else {
                warnx("no <host>:<dirpath> nfs-name");
                return (0);
        }
        *delimp = '\0';

        /*
         * If there has been a trailing slash at mounttime it seems
         * that some mountd implementations fail to remove the mount
         * entries from their mountlist while unmounting.
         */
        for (speclen = strlen(spec);
                speclen > 1 && spec[speclen - 1] == '/';
                speclen--)
                spec[speclen - 1] = '\0';
        if (strlen(hostp) + strlen(spec) + 1 > MNAMELEN) {
                warnx("%s:%s: %s", hostp, spec, strerror(ENAMETOOLONG));
                return (0);
        }
        /* Make both '@' and ':' notations equal */
        if (*hostp != '\0') {
                len = strlen(hostp);
                memmove(nam, hostp, len);
                nam[len] = ':';
                memmove(nam + len + 1, spec, speclen);
                nam[len + speclen + 1] = '\0';
        }

        /*
         * Handle an internet host address.
         */
        memset(&hints, 0, sizeof hints);
        hints.ai_flags = AI_NUMERICHOST;
        hints.ai_socktype = nfsargsp->sotype;
        if (getaddrinfo(hostp, portspec, &hints, &ai_nfs) != 0) {
                hints.ai_flags = 0;
                if ((ecode = getaddrinfo(hostp, portspec, &hints, &ai_nfs))
                    != 0) {
                        if (portspec == NULL)
                                errx(1, "%s: %s", hostp, gai_strerror(ecode));
                        else
                                errx(1, "%s:%s: %s", hostp, portspec,
                                    gai_strerror(ecode));
                        return (0);
                }
        }

        ret = TRYRET_LOCALERR;
        for (;;) {
                /*
                 * Try each entry returned by getaddrinfo(). Note the
                 * occurence of remote errors by setting `remoteerr'.
                 */
                remoteerr = 0;
                for (ai = ai_nfs; ai != NULL; ai = ai->ai_next) {
                        ret = nfs_tryproto(nfsargsp, ai, hostp, spec, &errstr);
                        if (ret == TRYRET_SUCCESS)
                                break;
                        if (ret != TRYRET_LOCALERR)
                                remoteerr = 1;
                        if ((opflags & ISBGRND) == 0)
                                fprintf(stderr, "%s\n", errstr);
                }
                if (ret == TRYRET_SUCCESS)
                        break;

                /* Exit if all errors were local. */
                if (!remoteerr)
                        exit(1);

                /*
                 * If retrycnt == 0, we are to keep retrying forever.
                 * Otherwise decrement it, and exit if it hits zero.
                 */
                if (retrycnt != 0 && --retrycnt == 0)
                        exit(1);

                if ((opflags & (BGRND | ISBGRND)) == BGRND) {
                        warnx("Cannot immediately mount %s:%s, backgrounding",
                            hostp, spec);
                        opflags |= ISBGRND;
                        if (daemon(0, 0) != 0)
                                err(1, "daemon");
                }
                sleep(60);
        }
        freeaddrinfo(ai_nfs);
        nfsargsp->hostname = nam;
        /* Add mounted filesystem to PATH_MOUNTTAB */
        if (!add_mtab(hostp, spec))
                warnx("can't update %s for %s:%s", PATH_MOUNTTAB, hostp, spec);
        return (1);
}

/*
 * Try to set up the NFS arguments according to the address
 * family, protocol (and possibly port) specified in `ai'.
 *
 * Returns TRYRET_SUCCESS if successful, or:
 *   TRYRET_TIMEOUT             The server did not respond.
 *   TRYRET_REMOTEERR           The server reported an error.
 *   TRYRET_LOCALERR            Local failure.
 *
 * In all error cases, *errstr will be set to a statically-allocated string
 * describing the error.
 */
static enum tryret
nfs_tryproto(struct nfs_args *nfsargsp, struct addrinfo *ai, char *hostp,
    char *spec, char **errstr)
{
        static char errbuf[256];
        struct sockaddr_storage nfs_ss;
        struct netbuf nfs_nb;
        struct nfhret nfhret;
        struct timeval try;
        struct rpc_err rpcerr;
        CLIENT *clp;
        struct netconfig *nconf, *nconf_mnt;
        const char *netid, *netid_mnt;
        int doconnect, nfsvers, mntvers;
        enum clnt_stat status;
        enum mountmode trymntmode;

        trymntmode = mountmode;
        errbuf[0] = '\0';
        *errstr = errbuf;

        if ((netid = netidbytype(ai->ai_family, nfsargsp->sotype)) == NULL) {
                snprintf(errbuf, sizeof errbuf,
                    "af %d sotype %d not supported", ai->ai_family,
                    nfsargsp->sotype);
                return (TRYRET_LOCALERR);
        }
        if ((nconf = getnetconf_cached(netid)) == NULL) {
                snprintf(errbuf, sizeof errbuf, "%s: %s", netid, nc_sperror());
                return (TRYRET_LOCALERR);
        }

        netid_mnt = netid;
        nconf_mnt = nconf;

tryagain:
        if (trymntmode == V2) {
                nfsvers = 2;
                mntvers = 1;
        } else {
                nfsvers = 3;
                mntvers = 3;
        }

        if (portspec != NULL) {
                /* `ai' contains the complete nfsd sockaddr. */
                nfs_nb.buf = ai->ai_addr;
                nfs_nb.len = nfs_nb.maxlen = ai->ai_addrlen;
        } else {
                /* Ask the remote rpcbind. */
                nfs_nb.buf = &nfs_ss;
                nfs_nb.len = nfs_nb.maxlen = sizeof nfs_ss;

                if (!rpcb_getaddr(RPCPROG_NFS, nfsvers, nconf, &nfs_nb,
                    hostp)) {
                        if (rpc_createerr.cf_stat == RPC_PROGVERSMISMATCH &&
                            trymntmode == ANY) {
                                trymntmode = V2;
                                goto tryagain;
                        }
                        snprintf(errbuf, sizeof errbuf, "[%s] %s:%s: %s",
                            netid, hostp, spec,
                            clnt_spcreateerror("RPCPROG_NFS"));
                        return (returncode(rpc_createerr.cf_stat,
                            &rpc_createerr.cf_error));
                }
        }

        /* Check that the server (nfsd) responds on the port we have chosen. */
        clp = clnt_tli_create(RPC_ANYFD, nconf, &nfs_nb, RPCPROG_NFS, nfsvers,
            0, 0);
        if (clp == NULL) {
                snprintf(errbuf, sizeof errbuf, "[%s] %s:%s: %s", netid,
                    hostp, spec, clnt_spcreateerror("nfsd: RPCPROG_NFS"));
                return (returncode(rpc_createerr.cf_stat,
                    &rpc_createerr.cf_error));
        }
        if (nfsargsp->sotype == SOCK_DGRAM &&
            !(nfsargsp->flags & NFSMNT_NOCONN)) {
                /*
                 * Use connect(), to match what the kernel does. This
                 * catches cases where the server responds from the
                 * wrong source address.
                 */
                doconnect = 1;
                if (!clnt_control(clp, CLSET_CONNECT, (char *)&doconnect)) {
                        clnt_destroy(clp);
                        snprintf(errbuf, sizeof errbuf,
                            "[%s] %s:%s: CLSET_CONNECT failed", netid, hostp,
                            spec);
                        return (TRYRET_LOCALERR);
                }
        }

        try.tv_sec = 10;
        try.tv_usec = 0;
        status = clnt_call(clp, NFSPROC_NULL, (xdrproc_t)xdr_void, NULL,
            (xdrproc_t)xdr_void, NULL, try);
        if (status != RPC_SUCCESS) {
                if (status == RPC_PROGVERSMISMATCH && trymntmode == ANY) {
                        clnt_destroy(clp);
                        trymntmode = V2;
                        goto tryagain;
                }
                clnt_geterr(clp, &rpcerr);
                snprintf(errbuf, sizeof errbuf, "[%s] %s:%s: %s", netid,
                    hostp, spec, clnt_sperror(clp, "NFSPROC_NULL"));
                clnt_destroy(clp);
                return (returncode(status, &rpcerr));
        }
        clnt_destroy(clp);

        /* Send the RPCMNT_MOUNT RPC to get the root filehandle. */
        try.tv_sec = 10;
        try.tv_usec = 0;
        clp = clnt_tp_create(hostp, RPCPROG_MNT, mntvers, nconf_mnt);
        if (clp == NULL) {
                snprintf(errbuf, sizeof errbuf, "[%s] %s:%s: %s", netid_mnt,
                    hostp, spec, clnt_spcreateerror("RPCMNT: clnt_create"));
                return (returncode(rpc_createerr.cf_stat,
                    &rpc_createerr.cf_error));
        }
        clp->cl_auth = authsys_create_default();
        nfhret.auth = RPCAUTH_UNIX;
        nfhret.vers = mntvers;
        status = clnt_call(clp, RPCMNT_MOUNT, (xdrproc_t)xdr_dir, spec,
            (xdrproc_t)xdr_fh, &nfhret, try);
        auth_destroy(clp->cl_auth);
        if (status != RPC_SUCCESS) {
                if (status == RPC_PROGVERSMISMATCH && trymntmode == ANY) {
                        clnt_destroy(clp);
                        trymntmode = V2;
                        goto tryagain;
                }
                clnt_geterr(clp, &rpcerr);
                snprintf(errbuf, sizeof errbuf, "[%s] %s:%s: %s", netid_mnt,
                    hostp, spec, clnt_sperror(clp, "RPCPROG_MNT"));
                clnt_destroy(clp);
                return (returncode(status, &rpcerr));
        }
        clnt_destroy(clp);

        if (nfhret.stat != 0) {
                snprintf(errbuf, sizeof errbuf, "[%s] %s:%s: %s", netid_mnt,
                    hostp, spec, strerror(nfhret.stat));
                return (TRYRET_REMOTEERR);
        }

        /*
         * Store the filehandle and server address in nfsargsp, making
         * sure to copy any locally allocated structures.
         */
        nfsargsp->addrlen = nfs_nb.len;
        nfsargsp->addr = malloc(nfsargsp->addrlen);
        nfsargsp->fhsize = nfhret.fhsize;
        nfsargsp->fh = malloc(nfsargsp->fhsize);
        if (nfsargsp->addr == NULL || nfsargsp->fh == NULL)
                err(1, "malloc");
        bcopy(nfs_nb.buf, nfsargsp->addr, nfsargsp->addrlen);
        bcopy(nfhret.nfh, nfsargsp->fh, nfsargsp->fhsize);

        if (nfsvers == 3)
                nfsargsp->flags |= NFSMNT_NFSV3;
        else
                nfsargsp->flags &= ~NFSMNT_NFSV3;

        return (TRYRET_SUCCESS);
}


/*
 * Catagorise a RPC return status and error into an `enum tryret'
 * return code.
 */
static enum tryret
returncode(enum clnt_stat status, struct rpc_err *rpcerr)
{
        switch (status) {
        case RPC_TIMEDOUT:
                return (TRYRET_TIMEOUT);
        case RPC_PMAPFAILURE:
        case RPC_PROGNOTREGISTERED:
        case RPC_PROGVERSMISMATCH:
        /* XXX, these can be local or remote. */
        case RPC_CANTSEND:
        case RPC_CANTRECV:
                return (TRYRET_REMOTEERR);
        case RPC_SYSTEMERROR:
                switch (rpcerr->re_errno) {
                case ETIMEDOUT:
                        return (TRYRET_TIMEOUT);
                case ENOMEM:
                        break;
                default:
                        return (TRYRET_REMOTEERR);
                }
                /* FALLTHROUGH */
        default:
                break;
        }
        return (TRYRET_LOCALERR);
}

/*
 * Look up a netid based on an address family and socket type.
 * `af' is the address family, and `sotype' is SOCK_DGRAM or SOCK_STREAM.
 *
 * XXX there should be a library function for this.
 */
static const char *
netidbytype(int af, int sotype)
{
        struct nc_protos *p;

        for (p = nc_protos; p->netid != NULL; p++) {
                if (af != p->af || sotype != p->sotype)
                        continue;
                return (p->netid);
        }
        return (NULL);
}

/*
 * Look up a netconfig entry based on a netid, and cache the result so
 * that we don't need to remember to call freenetconfigent().
 *
 * Otherwise it behaves just like getnetconfigent(), so nc_*error()
 * work on failure.
 */
static struct netconfig *
getnetconf_cached(const char *netid)
{
        static struct nc_entry {
                struct netconfig *nconf;
                struct nc_entry *next;
        } *head;
        struct nc_entry *p;
        struct netconfig *nconf;

        for (p = head; p != NULL; p = p->next)
                if (strcmp(netid, p->nconf->nc_netid) == 0)
                        return (p->nconf);

        if ((nconf = getnetconfigent(netid)) == NULL)
                return (NULL);
        if ((p = malloc(sizeof(*p))) == NULL)
                err(1, "malloc");
        p->nconf = nconf;
        p->next = head;
        head = p;

        return (p->nconf);
}

/*
 * xdr routines for mount rpc's
 */
static int
xdr_dir(XDR *xdrsp, char *dirp)
{
        return (xdr_string(xdrsp, &dirp, RPCMNT_PATHLEN));
}

static int
xdr_fh(XDR *xdrsp, struct nfhret *np)
{
        int i;
        long auth, authcnt, authfnd = 0;

        if (!xdr_u_long(xdrsp, &np->stat))
                return (0);
        if (np->stat)
                return (1);
        switch (np->vers) {
        case 1:
                np->fhsize = NFSX_V2FH;
                return (xdr_opaque(xdrsp, (caddr_t)np->nfh, NFSX_V2FH));
        case 3:
                if (!xdr_long(xdrsp, &np->fhsize))
                        return (0);
                if (np->fhsize <= 0 || np->fhsize > NFSX_V3FHMAX)
                        return (0);
                if (!xdr_opaque(xdrsp, (caddr_t)np->nfh, np->fhsize))
                        return (0);
                if (!xdr_long(xdrsp, &authcnt))
                        return (0);
                for (i = 0; i < authcnt; i++) {
                        if (!xdr_long(xdrsp, &auth))
                                return (0);
                        if (auth == np->auth)
                                authfnd++;
                }
                /*
                 * Some servers, such as DEC's OSF/1 return a nil authenticator
                 * list to indicate RPCAUTH_UNIX.
                 */
                if (!authfnd && (authcnt > 0 || np->auth != RPCAUTH_UNIX))
                        np->stat = EAUTH;
                return (1);
        }
        return (0);
}

static void
usage(void)
{
        fprintf(stderr, "%s\n%s\n%s\n%s\n",
"usage: mount_nfs [-23NPTUbcdils] [-D deadthresh] [-I readdirsize]",
"                 [-R retrycnt] [-a maxreadahead]",
"                 [-g maxgroups] [-o options] [-r readsize]",
"                 [-t timeout] [-w writesize] [-x retrans] rhost:path node");
        exit(1);
}