/*      $OpenBSD: host_ops.c,v 1.20 2021/10/21 10:55:56 deraadt Exp $   */

/*
 * Copyright (c) 1990 Jan-Simon Pendry
 * Copyright (c) 1990 Imperial College of Science, Technology & Medicine
 * Copyright (c) 1990, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Jan-Simon Pendry at Imperial College, London.
 *
 * 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.
 *
 *      from: @(#)host_ops.c    8.1 (Berkeley) 6/6/93
 */

#include "am.h"

#ifdef HAS_HOST

#include "mount.h"
#include <sys/stat.h>

/*
 * NFS host file system.
 * Mounts all exported filesystems from a given host.
 * This has now degenerated into a mess but will not
 * be rewritten.  Amd 6 will support the abstractions
 * needed to make this work correctly.
 */

/*
 * Define HOST_RPC_UDP to use dgram instead of stream RPC.
 * Datagrams are generally much faster.
 */
/*#define       HOST_RPC_UDP*/

/*
 * Define HOST_MKDIRS to make Amd automatically try
 * to create the mount points.
 */
#define HOST_MKDIRS

/*
 * Determine the mount point
 */
#define MAKE_MNTPT(mntpt, ex, mf) { \
                        if (strcmp((ex)->ex_dir, "/") == 0) \
                                strlcpy((mntpt), (mf)->mf_mount, sizeof((mntpt))); \
                        else \
                                snprintf((mntpt), sizeof(mntpt), "%s%s", (mf)->mf_mount, (ex)->ex_dir); \
}

/*
 * Execute needs the same as NFS plus a helper command
 */
static char *
host_match(am_opts *fo)
{
#ifdef HOST_EXEC
        if (!host_helper) {
                plog(XLOG_USER, "No host helper command given");
                return FALSE;
        }
#endif /* HOST_EXEC */

        /*
         * Make sure rfs is specified to keep nfs_match happy...
         */
        if (!fo->opt_rfs)
                fo->opt_rfs = "/";

        return (*nfs_ops.fs_match)(fo);
}

static int
host_init(mntfs *mf)
{
        if (strchr(mf->mf_info, ':') == 0)
                return ENOENT;
        return 0;
}

/*
 * Two implementations:
 * HOST_EXEC gets you the external version.  The program specified with
 * the -h option is called.  The external program is not published...
 * roll your own.
 *
 * Otherwise you get the native version.  Faster but makes the program
 * bigger.
 */

#ifndef HOST_EXEC

static bool_t
xdr_pri_free(xdrproc_t xdr_args, void *args_ptr)
{
        XDR xdr;

        xdr.x_op = XDR_FREE;
        return ((*xdr_args)(&xdr, args_ptr));
}

static int
do_mount(fhstatus *fhp, char *dir, char *fs_name, char *opts, mntfs *mf)
{
        struct stat stb;

#ifdef DEBUG
        dlog("host: mounting fs %s on %s", fs_name, dir);
#endif /* DEBUG */
#ifdef HOST_MKDIRS
        (void) mkdirs(dir, 0555);
#endif /* HOST_MKDIRS */
        if (stat(dir, &stb) < 0 || (stb.st_mode & S_IFMT) != S_IFDIR) {
                plog(XLOG_ERROR, "No mount point for %s - skipping", dir);
                return ENOENT;
        }

        return mount_nfs_fh(fhp, dir, fs_name, opts, mf);
}

static int
sortfun(const void *arg1, const void *arg2)
{
        const exports *a = arg1, *b = arg2;
        return strcmp((*a)->ex_dir, (*b)->ex_dir);
}

/*
 * Get filehandle
 */
static int
fetch_fhandle(CLIENT *client, char *dir, fhstatus *fhp)
{
        struct timeval tv;
        enum clnt_stat clnt_stat;

        /*
         * Pick a number, any number...
         */
        tv.tv_sec = 20;
        tv.tv_usec = 0;

#ifdef DEBUG
        dlog("Fetching fhandle for %s", dir);
#endif /* DEBUG */
        /*
         * Call the mount daemon on the remote host to
         * get the filehandle.
         */
        fhp->fhs_vers = MOUNTVERS;
        clnt_stat = clnt_call(client, MOUNTPROC_MNT, xdr_dirpath, &dir, xdr_fhstatus, fhp, tv);
        if (clnt_stat != RPC_SUCCESS) {
                char *msg = clnt_sperrno(clnt_stat);
                plog(XLOG_ERROR, "mountd rpc failed: %s", msg);
                return EIO;
        }
        /*
         * Check status of filehandle
         */
        if (fhp->fhs_stat) {
#ifdef DEBUG
                errno = fhp->fhs_stat;
                dlog("fhandle fetch failed: %m");
#endif /* DEBUG */
                return fhp->fhs_stat;
        }
        return 0;
}

/*
 * Scan mount table to see if something already mounted
 */
static int
already_mounted(mntlist *mlist, char *dir)
{
        mntlist *ml;

        for (ml = mlist; ml; ml = ml->mnext)
                if (strcmp(ml->mnt->mnt_dir, dir) == 0)
                        return 1;
        return 0;
}

/*
 * Mount the export tree from a host
 */
static int
host_fmount(mntfs *mf)
{
        struct timeval tv2;
        CLIENT *client;
        enum clnt_stat clnt_stat;
        int n_export;
        int j, k;
        exports exlist = 0, ex;
        exports *ep = 0;
        fhstatus *fp = 0;
        char *host = mf->mf_server->fs_host;
        int error = 0;
        struct sockaddr_in sin;
        int sock = RPC_ANYSOCK;
        int ok = FALSE;
        mntlist *mlist;
        char fs_name[PATH_MAX], *rfs_dir;
        char mntpt[PATH_MAX];
        struct timeval tv;
        tv.tv_sec = 10; tv.tv_usec = 0;

        /*
         * Read the mount list
         */
        mlist = read_mtab(mf->mf_mount);

        /*
         * Take a copy of the server address
         */
        sin = *mf->mf_server->fs_ip;

        /*
         * Zero out the port - make sure we recompute
         */
        sin.sin_port = 0;
        /*
         * Make a client end-point.
         * Try TCP first
         */
        if ((client = clnttcp_create(&sin, MOUNTPROG, MOUNTVERS, &sock, 0, 0)) == NULL &&
                (client = clntudp_create(&sin, MOUNTPROG, MOUNTVERS, tv, &sock)) == NULL) {
                plog(XLOG_ERROR, "Failed to make rpc connection to mountd on %s", host);
                error = EIO;
                goto out;
        }

        if (!nfs_auth) {
                error = make_nfs_auth();
                if (error)
                        goto out;
        }

        client->cl_auth = nfs_auth;

#ifdef DEBUG
        dlog("Fetching export list from %s", host);
#endif /* DEBUG */

        /*
         * Fetch the export list
         */
        tv2.tv_sec = 10; tv2.tv_usec = 0;
        clnt_stat = clnt_call(client, MOUNTPROC_EXPORT, xdr_void, 0, xdr_exports, &exlist, tv2);
        if (clnt_stat != RPC_SUCCESS) {
                /*clnt_perror(client, "rpc");*/
                error = EIO;
                goto out;
        }

        /*
         * Figure out how many exports were returned
         */
        for (n_export = 0, ex = exlist; ex; ex = ex->ex_next) {
                /*printf("export %s\n", ex->ex_dir);*/
                n_export++;
        }
#ifdef DEBUG
        /*dlog("%d exports returned", n_export);*/
#endif /* DEBUG */

        /*
         * Allocate an array of pointers into the list
         * so that they can be sorted.  If the filesystem
         * is already mounted then ignore it.
         */
        ep = xreallocarray(NULL, n_export, sizeof *ep);
        for (j = 0, ex = exlist; ex; ex = ex->ex_next) {
                MAKE_MNTPT(mntpt, ex, mf);
                if (!already_mounted(mlist, mntpt))
                        ep[j++] = ex;
        }
        n_export = j;

        /*
         * Sort into order.
         * This way the mounts are done in order down the tree,
         * instead of any random order returned by the mount
         * daemon (the protocol doesn't specify...).
         */
        qsort(ep, n_export, sizeof(exports), sortfun);

        /*
         * Allocate an array of filehandles
         */
        fp = xreallocarray(NULL, n_export, sizeof *fp);

        /*
         * Try to obtain filehandles for each directory.
         * If a fetch fails then just zero out the array
         * reference but discard the error.
         */
        for (j = k = 0; j < n_export; j++) {
                /* Check and avoid a duplicated export entry */
                if (j > k && ep[k] && strcmp(ep[j]->ex_dir, ep[k]->ex_dir) == 0) {
#ifdef DEBUG
                        dlog("avoiding dup fhandle requested for %s", ep[j]->ex_dir);
#endif
                        ep[j] = 0;
                } else {
                        k = j;
                        if ((error = fetch_fhandle(client, ep[j]->ex_dir, &fp[j])))
                                ep[j] = 0;
                }
        }

        /*
         * Mount each filesystem for which we have a filehandle.
         * If any of the mounts succeed then mark "ok" and return
         * error code 0 at the end.  If they all fail then return
         * the last error code.
         */
        strlcpy(fs_name, mf->mf_info, sizeof(fs_name));
        if ((rfs_dir = strchr(fs_name, ':')) == (char *) 0) {
                plog(XLOG_FATAL, "host_fmount: mf_info has no colon");
                error = EINVAL;
                goto out;
        }
        ++rfs_dir;
        for (j = 0; j < n_export; j++) {
                ex = ep[j];
                if (ex) {
                        strlcpy(rfs_dir, ex->ex_dir, fs_name + sizeof fs_name - rfs_dir);
                        MAKE_MNTPT(mntpt, ex, mf);
                        if (do_mount(&fp[j], mntpt, fs_name, mf->mf_mopts, mf) == 0)
                                ok = TRUE;
                }
        }

        /*
         * Clean up and exit
         */
out:
        discard_mntlist(mlist);
        free(ep);
        free(fp);
        if (client)
                clnt_destroy(client);
        if (exlist)
                xdr_pri_free(xdr_exports, &exlist);
        if (ok)
                return 0;
        return error;
}

/*
 * Return true if pref is a directory prefix of dir.
 *
 * TODO:
 * Does not work if pref is "/".
 */
static int
directory_prefix(char *pref, char *dir)
{
        int len = strlen(pref);
        if (strncmp(pref, dir, len) != 0)
                return FALSE;
        if (dir[len] == '/' || dir[len] == '\0')
                return TRUE;
        return FALSE;
}

/*
 * Unmount a mount tree
 */
static int
host_fumount(mntfs *mf)
{
        mntlist *ml, *mprev;
        int xerror = 0;

        /*
         * Read the mount list
         */
        mntlist *mlist = read_mtab(mf->mf_mount);

        /*
         * Reverse list...
         */
        ml = mlist;
        mprev = 0;
        while (ml) {
                mntlist *ml2 = ml->mnext;
                ml->mnext = mprev;
                mprev = ml;
                ml = ml2;
        }
        mlist = mprev;

        /*
         * Unmount all filesystems...
         */
        for (ml = mlist; ml && !xerror; ml = ml->mnext) {
                char *dir = ml->mnt->mnt_dir;
                if (directory_prefix(mf->mf_mount, dir)) {
                        int error;
#ifdef DEBUG
                        dlog("host: unmounts %s", dir);
#endif /* DEBUG */
                        /*
                         * Unmount "dir"
                         */
                        error = umount_fs(dir);
                        /*
                         * Keep track of errors
                         */
                        if (error) {
                                if (!xerror)
                                        xerror = error;
                                if (error != EBUSY) {
                                        errno = error;
                                        plog(XLOG_ERROR, "Tree unmount of %s failed: %m", ml->mnt->mnt_dir);
                                }
                        } else {
#ifdef HOST_MKDIRS
                                (void) rmdirs(dir);
#endif /* HOST_MKDIRS */
                        }
                }
        }

        /*
         * Throw away mount list
         */
        discard_mntlist(mlist);

        /*
         * Try to remount, except when we are shutting down.
         */
        if (xerror && amd_state != Finishing) {
                xerror = host_fmount(mf);
                if (!xerror) {
                        /*
                         * Don't log this - it's usually too verbose
                        plog(XLOG_INFO, "Remounted host %s", mf->mf_info);
                         */
                        xerror = EBUSY;
                }
        }
        return xerror;
}

/*
 * Tell mountd we're done.
 * This is not quite right, because we may still
 * have other filesystems mounted, but the existing
 * mountd protocol is badly broken anyway.
 */
static void host_umounted(am_node *mp)
{
}


#else /* HOST_EXEC */

static int
host_exec(char *op, char *host, char *fs, char *opts)
{
        int error;
        char *argv[7];

        /*
         * Build arg vector
         */
        argv[0] = host_helper;
        argv[1] = host_helper;
        argv[2] = op;
        argv[3] = host;
        argv[4] = fs;
        argv[5] = opts && *opts ? opts : "rw,default";
        argv[6] = 0;

        /*
         * Put stdout to stderr
         */
        (void) fclose(stdout);
        (void) dup(fileno(logfp));
        if (fileno(logfp) != fileno(stderr)) {
                (void) fclose(stderr);
                (void) dup(fileno(logfp));
        }
        /*
         * Try the exec
         */
#ifdef DEBUG
        Debug(D_FULL) {
                char **cp = argv;
                plog(XLOG_DEBUG, "executing (un)mount command...");
                while (*cp) {
                        plog(XLOG_DEBUG, "arg[%d] = '%s'", cp-argv, *cp);
                        cp++;
                }
        }
#endif /* DEBUG */
        if (argv[0] == 0 || argv[1] == 0) {
                errno = EINVAL;
                plog(XLOG_USER, "1st/2nd args missing to (un)mount program");
        } else {
                (void) execv(argv[0], argv+1);
        }
        /*
         * Save error number
         */
        error = errno;
        plog(XLOG_ERROR, "exec %s failed: %m", argv[0]);

        /*
         * Return error
         */
        return error;
}

static int
host_mount(am_node *mp)
{
        mntfs *mf = mp->am_mnt;

        return host_exec("mount", mf->mf_server->fs_host, mf->mf_mount, mf->mf_opts);
}

static int
host_umount(am_node *mp)
{
        mntfs *mf = mp->am_mnt;

        return host_exec("unmount", mf->mf_server->fs_host, mf->mf_mount, "xxx");
}

#endif /* HOST_EXEC */

/*
 * Ops structure
 */
am_ops host_ops = {
        "host",
        host_match,
        host_init,
        auto_fmount,
        host_fmount,
        auto_fumount,
        host_fumount,
        efs_lookuppn,
        efs_readdir,
        0, /* host_readlink */
        0, /* host_mounted */
#ifdef HOST_EXEC
        0, /* host_umounted */
#else
        host_umounted,
#endif
        find_nfs_srvr,
        FS_MKMNT|FS_BACKGROUND|FS_AMQINFO
};

#endif /* HAS_HOST */