/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*        All Rights Reserved   */

/*
 * University Copyright- Copyright (c) 1982, 1986, 1988
 * The Regents of the University of California
 * All Rights Reserved
 *
 * University Acknowledgment- Portions of this document are derived from
 * software developed by the University of California, Berkeley, and its
 * contributors.
 */

/*
 * nfs umount
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <signal.h>
#include <unistd.h>
#include <kstat.h>
#include <rpc/rpc.h>
#include <sys/mnttab.h>
#include <sys/mount.h>
#include <sys/mntent.h>
#include <nfs/nfs.h>
#include <nfs/nfs_clnt.h>
#include <rpcsvc/mount.h>
#include <errno.h>
#include <locale.h>
#include <fslib.h>
#include <priv.h>
#include <tsol/label.h>
#include "replica.h"

#define RET_OK  0
#define RET_ERR 32

#ifdef __STDC__
static void pr_err(const char *fmt, ...);
#else
static void pr_err(char *fmt, va_dcl);
#endif
static  void    usage();
static  int     nfs_unmount(char *, int);
static  void    inform_server(char *, char *, bool_t);
static  struct extmnttab *mnttab_find();
extern int __clnt_bindresvport(CLIENT *);

static  int is_v4_mount(struct extmnttab *);

static char *myname;
static char typename[64];

int
main(int argc, char *argv[])
{
        extern int optind;
        int c;
        int umnt_flag = 0;

        (void) setlocale(LC_ALL, "");

#if !defined(TEXT_DOMAIN)
#define TEXT_DOMAIN "SYS_TEST"
#endif
        (void) textdomain(TEXT_DOMAIN);

        myname = strrchr(argv[0], '/');
        myname = myname ? myname+1 : argv[0];
        (void) snprintf(typename, sizeof (typename), "nfs %s", myname);
        argv[0] = typename;

        /*
         * Set options
         */
        while ((c = getopt(argc, argv, "f")) != EOF) {
                switch (c) {
                case 'f':
                        umnt_flag |= MS_FORCE; /* forced unmount is desired */
                        break;
                default:
                        usage();
                        exit(RET_ERR);
                }
        }
        if (argc - optind != 1) {
                usage();
                exit(RET_ERR);
        }

        if (!priv_ineffect(PRIV_SYS_MOUNT) ||
            !priv_ineffect(PRIV_NET_PRIVADDR)) {
                pr_err(gettext("insufficient privileges\n"));
                exit(RET_ERR);
        }

        /*
         * On a labeled system, a MAC flag may be needed if the mount is
         * read-down, so attempt to assert it but ignore errors in any case.
         */
        if (is_system_labeled())
                (void) setpflags(NET_MAC_AWARE, 1);

        /*
         * exit, really
         */
        return (nfs_unmount(argv[optind], umnt_flag));
}

static void
pr_err(const char *fmt, ...)
{
        va_list ap;

        va_start(ap, fmt);
        (void) fprintf(stderr, "%s: ", typename);
        (void) vfprintf(stderr, fmt, ap);
        (void) fflush(stderr);
        va_end(ap);
}

static void
usage()
{
        (void) fprintf(stderr,
            gettext("Usage: nfs umount [-f] {server:path | dir}\n"));
        exit(RET_ERR);
}

static int
nfs_unmount(char *pathname, int umnt_flag)
{
        struct extmnttab *mntp;
        bool_t quick = FALSE;
        int is_v4 = FALSE;

        mntp = mnttab_find(pathname);
        if (mntp) {
                pathname = mntp->mnt_mountp;
        }

        if (mntp)
                is_v4 = is_v4_mount(mntp);

        /* Forced unmount will almost always be successful */
        if (umount2(pathname, umnt_flag) < 0) {
                if (errno == EBUSY) {
                        pr_err(gettext("%s: is busy\n"), pathname);
                } else {
                        pr_err(gettext("%s: not mounted\n"), pathname);
                }
                return (RET_ERR);
        }

        /* All done if it's v4 */
        if (is_v4 == TRUE)
                return (RET_OK);

        /* Inform server quickly in case of forced unmount */
        if (umnt_flag & MS_FORCE)
                quick = TRUE;

        if (mntp) {
                inform_server(mntp->mnt_special, mntp->mnt_mntopts, quick);
        }

        return (RET_OK);
}

/*
 *  Find the mnttab entry that corresponds to "name".
 *  We're not sure what the name represents: either
 *  a mountpoint name, or a special name (server:/path).
 *  Return the last entry in the file that matches.
 */
static struct extmnttab *
mnttab_find(dirname)
        char *dirname;
{
        FILE *fp;
        struct extmnttab mnt;
        struct extmnttab *res = NULL;

        fp = fopen(MNTTAB, "r");
        if (fp == NULL) {
                pr_err("%s: %s\n", MNTTAB, strerror(errno));
                return (NULL);
        }
        while (getextmntent(fp, &mnt, sizeof (struct extmnttab)) == 0) {
                if (strcmp(mnt.mnt_mountp, dirname) == 0 ||
                    strcmp(mnt.mnt_special, dirname) == 0) {
                        if (res)
                                fsfreemnttab(res);
                        res = fsdupmnttab(&mnt);
                }
        }

        (void) fclose(fp);
        return (res);
}

/*
 * If quick is TRUE, it will try to inform server quickly
 * as possible.
 */
static void
inform_server(char *string, char *opts, bool_t quick)
{
        struct timeval timeout;
        CLIENT *cl;
        enum clnt_stat rpc_stat;
        struct replica *list;
        int i, n;
        char *p = NULL;
        static struct timeval create_timeout = {5, 0};
        static struct timeval *timep;

        list = parse_replica(string, &n);

        if (list == NULL) {
                if (n < 0)
                        pr_err(gettext("%s is not hostname:path format\n"),
                            string);
                else
                        pr_err(gettext("no memory\n"));
                return;
        }

        /*
         * If mounted with -o public, then no need to contact server
         * because mount protocol was not used.
         */
        if (opts != NULL)
                p = strstr(opts, MNTOPT_PUBLIC);

        if (p != NULL) {
                i = strlen(MNTOPT_PUBLIC);
                /*
                 * Now make sure the match of "public" isn't a substring
                 * of another option.
                 */
                if (((p == opts) || (*(p-1) == ',')) &&
                    ((p[i] == ',') || (p[i] == '\0')))
                        return;
        }

        for (i = 0; i < n; i++) {
                int vers;

                /*
                 * Skip file systems mounted using WebNFS, because mount
                 * protocol was not used.
                 */
                if (strcmp(list[i].host, "nfs") == 0 && strncmp(list[i].path,
                    "//", 2) == 0)
                        continue;

                vers =  MOUNTVERS;
retry:
                /*
                 * Use 5 sec. timeout if file system is forced unmounted,
                 * otherwise use default timeout to create a client handle.
                 * This would minimize the time to force unmount a file
                 * system reside on a server that is down.
                 */
                timep = (quick ? &create_timeout : NULL);
                cl = clnt_create_timed(list[i].host, MOUNTPROG, vers,
                    "datagram_n", timep);
                /*
                 * Do not print any error messages in case of forced
                 * unmount.
                 */
                if (cl == NULL) {
                        if (!quick)
                                pr_err("%s:%s %s\n", list[i].host, list[i].path,
                                    clnt_spcreateerror(
                                    "server not responding"));
                        continue;
                }
                /*
                 * Now it is most likely that the NFS client will be able
                 * to contact the server since rpcbind is running on
                 * the server. There is still a small window in which
                 * server can be unreachable.
                 */

                if (__clnt_bindresvport(cl) < 0) {
                        if (!quick)
                                pr_err(gettext(
                                    "couldn't bind to reserved port\n"));
                        clnt_destroy(cl);
                        return;
                }
                if ((cl->cl_auth = authsys_create_default()) == NULL) {
                        if (!quick)
                                pr_err(gettext(
                                    "couldn't create authsys structure\n"));
                        clnt_destroy(cl);
                        return;
                }
                timeout.tv_usec = 0;
                timeout.tv_sec = 5;
                clnt_control(cl, CLSET_RETRY_TIMEOUT, (char *)&timeout);
                timeout.tv_sec = 25;
                rpc_stat = clnt_call(cl, MOUNTPROC_UMNT, xdr_dirpath,
                    (char *)&list[i].path, xdr_void, (char *)NULL,
                    timeout);
                AUTH_DESTROY(cl->cl_auth);
                clnt_destroy(cl);
                if (rpc_stat == RPC_PROGVERSMISMATCH && vers == MOUNTVERS) {
                        /*
                         * The rare case of a v3-only server
                         */
                        vers = MOUNTVERS3;
                        goto retry;
                }
                if (rpc_stat != RPC_SUCCESS)
                        pr_err("%s\n", clnt_sperror(cl, "unmount"));
        }

        free_replica(list, n);
}

/*
 * This function's behavior is taken from nfsstat.
 * Trying to determine what NFS version was used for the mount.
 */
int
is_v4_mount(struct extmnttab *mntp)
{
        kstat_ctl_t *kc = NULL;         /* libkstat cookie */
        kstat_t *ksp;
        struct mntinfo_kstat mik;

        if (mntp == NULL)
                return (FALSE);

        if ((kc = kstat_open()) == NULL)
                return (FALSE);

        for (ksp = kc->kc_chain; ksp; ksp = ksp->ks_next) {
                if (ksp->ks_type != KSTAT_TYPE_RAW)
                        continue;
                if (strcmp(ksp->ks_module, "nfs") != 0)
                        continue;
                if (strcmp(ksp->ks_name, "mntinfo") != 0)
                        continue;
                if (mntp->mnt_minor != ksp->ks_instance)
                        continue;

                if (kstat_read(kc, ksp, &mik) == -1)
                        continue;

                if (mik.mik_vers == 4)
                        return (TRUE);
                else
                        return (FALSE);
        }
        return (FALSE);
}