/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * Copyright (c) 2016 Tomohiro Kusumi <tkusumi@netbsd.org>
 * Copyright (c) 2016 The DragonFly Project
 * Copyright (c) 2014 The FreeBSD Foundation
 * All rights reserved.
 *
 * This software was developed by Edward Tomasz Napierala under sponsorship
 * from the FreeBSD Foundation.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 *
 */

#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/stat.h>

#include "autofs.h"
#include "autofs_mount.h"

static int      autofs_statfs(struct mount *mp, struct statfs *sbp,
                    struct ucred *cred);

static struct objcache_malloc_args autofs_request_args = {
        sizeof(struct autofs_request), M_AUTOFS,
};
static struct objcache_malloc_args autofs_node_args = {
        sizeof(struct autofs_node), M_AUTOFS,
};

static int
autofs_init(struct vfsconf *vfsp)
{
        KASSERT(autofs_softc == NULL,
            ("softc %p, should be NULL", autofs_softc));

        autofs_softc = kmalloc(sizeof(*autofs_softc), M_AUTOFS,
            M_WAITOK | M_ZERO);

        autofs_request_objcache = objcache_create("autofs_request", 0, 0,
                NULL, NULL, NULL,
                objcache_malloc_alloc_zero, objcache_malloc_free,
                &autofs_request_args);

        autofs_node_objcache = objcache_create("autofs_node", 0, 0,
                NULL, NULL, NULL,
                objcache_malloc_alloc_zero, objcache_malloc_free,
                &autofs_node_args);

        TAILQ_INIT(&autofs_softc->sc_requests);
        cv_init(&autofs_softc->sc_cv, "autofscv");
        mtx_init(&autofs_softc->sc_lock, "autofssclk");
        autofs_softc->sc_dev_opened = false;

        autofs_softc->sc_cdev = make_dev(&autofs_ops, 0, UID_ROOT, GID_OPERATOR,
            0640, "autofs");
        if (autofs_softc->sc_cdev == NULL) {
                AUTOFS_WARN("failed to create device node");
                objcache_destroy(autofs_request_objcache);
                objcache_destroy(autofs_node_objcache);
                kfree(autofs_softc, M_AUTOFS);
                return (ENODEV);
        }
        autofs_softc->sc_cdev->si_drv1 = autofs_softc;

        return (0);
}

static int
autofs_uninit(struct vfsconf *vfsp)
{
        mtx_lock_ex_quick(&autofs_softc->sc_lock);
        if (autofs_softc->sc_dev_opened) {
                mtx_unlock_ex(&autofs_softc->sc_lock);
                return (EBUSY);
        }

        if (autofs_softc->sc_cdev != NULL)
                destroy_dev(autofs_softc->sc_cdev);

        objcache_destroy(autofs_request_objcache);
        objcache_destroy(autofs_node_objcache);

        mtx_unlock_ex(&autofs_softc->sc_lock);

        kfree(autofs_softc, M_AUTOFS); /* race with open */
        autofs_softc = NULL;

        return (0);
}

static int
autofs_mount(struct mount *mp, char *mntpt, caddr_t data, struct ucred *cred)
{
        struct autofs_mount_info info;
        struct autofs_mount *amp;
        struct statfs *sbp = &mp->mnt_stat;
        int error;

        if (mp->mnt_flag & MNT_UPDATE) {
                autofs_flush(VFSTOAUTOFS(mp));
                return (0);
        }

        error = copyin(data, &info, sizeof(info));
        if (error)
                return (error);

        /*
         * Copy-in ->f_mntfromname string.
         */
        memset(sbp->f_mntfromname, 0, sizeof(sbp->f_mntfromname));
        error = copyinstr(info.from, sbp->f_mntfromname,
            sizeof(sbp->f_mntfromname), NULL);
        if (error)
                return (error);
        /*
         * Copy-in ->f_mntonname string.
         */
        memset(sbp->f_mntonname, 0, sizeof(sbp->f_mntonname));
        error = copyinstr(mntpt, sbp->f_mntonname, sizeof(sbp->f_mntonname),
            NULL);
        if (error)
                return (error);

        /*
         * Allocate the autofs mount.
         */
        amp = kmalloc(sizeof(*amp), M_AUTOFS, M_WAITOK | M_ZERO);
        mp->mnt_data = (qaddr_t)amp;
        strlcpy(amp->am_from, sbp->f_mntfromname, sizeof(amp->am_from));
        strlcpy(amp->am_on, sbp->f_mntonname, sizeof(amp->am_on));

        /*
         * Copy-in master_options string.
         */
        error = copyinstr(info.master_options, amp->am_options,
            sizeof(amp->am_options), NULL);
        if (error)
                goto fail;
        /*
         * Copy-in master_prefix string.
         */
        error = copyinstr(info.master_prefix, amp->am_prefix,
            sizeof(amp->am_prefix), NULL);
        if (error)
                goto fail;

        /*
         * Initialize the autofs mount.
         */
        mtx_init(&amp->am_lock, "autofsmnlk");
        amp->am_last_ino = AUTOFS_ROOTINO;

        mtx_lock_ex_quick(&amp->am_lock);
        error = autofs_node_new(NULL, amp, ".", -1, &amp->am_root);
        mtx_unlock_ex(&amp->am_lock);
        KKASSERT(error == 0);
        KKASSERT(amp->am_root->an_ino == AUTOFS_ROOTINO);

        vfs_getnewfsid(mp);
        vfs_add_vnodeops(mp, &autofs_vnode_vops, &mp->mnt_vn_norm_ops);

        VFS_STATFS(mp, &mp->mnt_stat, cred);

        return (0);

fail:
        kfree(amp, M_AUTOFS);
        return (error);
}

static int
autofs_unmount(struct mount *mp, int mntflags)
{
        struct autofs_mount *amp = VFSTOAUTOFS(mp);
        int error, flags;

        flags = 0;
        if (mntflags & MNT_FORCE)
                flags |= FORCECLOSE;
        error = vflush(mp, 0, flags);
        if (error) {
                AUTOFS_DEBUG("vflush failed with error %d", error);
                return (error);
        }

        /*
         * All vnodes are gone, and new one will not appear - so,
         * no new triggerings.
         */
        for (;;) {
                struct autofs_request *ar;
                int dummy;
                bool found;

                found = false;
                mtx_lock_ex_quick(&autofs_softc->sc_lock);
                TAILQ_FOREACH(ar, &autofs_softc->sc_requests, ar_next) {
                        if (ar->ar_mount != amp)
                                continue;
                        ar->ar_error = ENXIO;
                        ar->ar_done = true;
                        ar->ar_in_progress = false;
                        found = true;
                }
                if (found == false) {
                        mtx_unlock_ex(&autofs_softc->sc_lock);
                        break;
                }

                cv_broadcast(&autofs_softc->sc_cv);
                mtx_unlock_ex(&autofs_softc->sc_lock);

                tsleep(&dummy, 0, "autofs_umount", hz);
        }

        mtx_lock_ex_quick(&amp->am_lock);
        while (!RB_EMPTY(&amp->am_root->an_children)) {
                struct autofs_node *anp;
                /*
                 * Force delete all nodes when more than one level of
                 * directories are created via indirect map. Autofs doesn't
                 * support rmdir(2), thus this is the only way to get out.
                 */
                anp = RB_MIN(autofs_node_tree, &amp->am_root->an_children);
                while (!RB_EMPTY(&anp->an_children))
                        anp = RB_MIN(autofs_node_tree, &anp->an_children);
                autofs_node_delete(anp);
        }
        autofs_node_delete(amp->am_root);
        mp->mnt_data = NULL;
        mtx_unlock_ex(&amp->am_lock);

        mtx_uninit(&amp->am_lock);

        kfree(amp, M_AUTOFS);

        return (0);
}

static int
autofs_root(struct mount *mp, struct vnode **vpp)
{
        struct autofs_mount *amp = VFSTOAUTOFS(mp);
        int error;

        KASSERT(amp->am_root, ("no root node"));

        error = autofs_node_vn(amp->am_root, mp, LK_EXCLUSIVE, vpp);
        if (error == 0) {
                struct vnode *vp = *vpp;
                vp->v_flag |= VROOT;
                KKASSERT(vp->v_type == VDIR);
        }

        return (error);
}

static int
autofs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
{
        sbp->f_bsize = S_BLKSIZE;
        sbp->f_iosize = 0;
        sbp->f_blocks = 0;
        sbp->f_bfree = 0;
        sbp->f_bavail = 0;
        sbp->f_files = 0;
        sbp->f_ffree = 0;

        return (0);
}

static int
autofs_statvfs(struct mount *mp, struct statvfs *sbp, struct ucred *cred)
{
        sbp->f_bsize = S_BLKSIZE;
        sbp->f_frsize = 0;
        sbp->f_blocks = 0;
        sbp->f_bfree = 0;
        sbp->f_bavail = 0;
        sbp->f_files = 0;
        sbp->f_ffree = 0;

        return (0);
}

static struct vfsops autofs_vfsops = {
        .vfs_flags =            0,
        .vfs_mount =            autofs_mount,
        .vfs_unmount =          autofs_unmount,
        .vfs_root =             autofs_root,
        .vfs_statfs =           autofs_statfs,
        .vfs_statvfs =          autofs_statvfs,
        .vfs_init =             autofs_init,
        .vfs_uninit =           autofs_uninit,
};

VFS_SET(autofs_vfsops, autofs, VFCF_SYNTHETIC | VFCF_MPSAFE);
MODULE_VERSION(autofs, 1);