/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2000,2004
 *      Poul-Henning Kamp.  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. 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: FreeBSD: src/sys/miscfs/kernfs/kernfs_vfsops.c 1.36
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/dirent.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/vnode.h>

#include <sys/kdb.h>

#include <fs/devfs/devfs.h>
#include <fs/devfs/devfs_int.h>

#include <security/mac/mac_framework.h>

/*
 * The one true (but secret) list of active devices in the system.
 * Locked by dev_lock()/devmtx
 */
struct cdev_priv_list cdevp_list = TAILQ_HEAD_INITIALIZER(cdevp_list);

struct unrhdr *devfs_inos;

static MALLOC_DEFINE(M_DEVFS2, "DEVFS2", "DEVFS data 2");
static MALLOC_DEFINE(M_DEVFS3, "DEVFS3", "DEVFS data 3");
static MALLOC_DEFINE(M_CDEVP, "DEVFS1", "DEVFS cdev_priv storage");

SYSCTL_NODE(_vfs, OID_AUTO, devfs, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "DEVFS filesystem");

static unsigned devfs_generation;
SYSCTL_UINT(_vfs_devfs, OID_AUTO, generation, CTLFLAG_RD,
        &devfs_generation, 0, "DEVFS generation number");

unsigned devfs_rule_depth = 1;
SYSCTL_UINT(_vfs_devfs, OID_AUTO, rule_depth, CTLFLAG_RW,
        &devfs_rule_depth, 0, "Max depth of ruleset include");

/*
 * Helper sysctl for devname(3).  We're given a dev_t and return the
 * name, if any, registered by the device driver.
 */
static int
sysctl_devname(SYSCTL_HANDLER_ARGS)
{
        int error;
        dev_t ud;
#ifdef COMPAT_FREEBSD11
        uint32_t ud_compat;
#endif
        struct cdev_priv *cdp;
        struct cdev *dev;

        if (req->newptr == NULL)
                return (EINVAL);

#ifdef COMPAT_FREEBSD11
        if (req->newlen == sizeof(ud_compat)) {
                error = SYSCTL_IN(req, &ud_compat, sizeof(ud_compat));
                if (error == 0)
                        ud = ud_compat == (uint32_t)NODEV ? NODEV : ud_compat;
        } else
#endif
                error = SYSCTL_IN(req, &ud, sizeof (ud));
        if (error)
                return (error);
        if (ud == NODEV)
                return (EINVAL);
        dev = NULL;
        dev_lock();
        TAILQ_FOREACH(cdp, &cdevp_list, cdp_list)
                if (cdp->cdp_inode == ud) {
                        dev = &cdp->cdp_c;
                        dev_refl(dev);
                        break;
                }
        dev_unlock();
        if (dev == NULL)
                return (ENOENT);
        error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
        dev_rel(dev);
        return (error);
}

SYSCTL_PROC(_kern, OID_AUTO, devname,
    CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY|CTLFLAG_MPSAFE,
    NULL, 0, sysctl_devname, "", "devname(3) handler");

SYSCTL_SIZEOF_STRUCT(cdev);
SYSCTL_SIZEOF_STRUCT(cdev_priv);

struct cdev *
devfs_alloc(int flags)
{
        struct cdev_priv *cdp;
        struct cdev *cdev;
        struct timespec ts;

        cdp = malloc(sizeof *cdp, M_CDEVP, M_ZERO |
            ((flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK));
        if (cdp == NULL)
                return (NULL);

        mtx_init(&cdp->cdp_threadlock, "devthrd", NULL, MTX_DEF);

        cdp->cdp_dirents = &cdp->cdp_dirent0;

        cdev = &cdp->cdp_c;
        LIST_INIT(&cdev->si_children);
        vfs_timestamp(&ts);
        cdev->si_atime = cdev->si_mtime = cdev->si_ctime = ts;

        return (cdev);
}

int
devfs_dev_exists(const char *name)
{
        struct cdev_priv *cdp;

        dev_lock_assert_locked();

        TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
                if ((cdp->cdp_flags & CDP_ACTIVE) == 0)
                        continue;
                if (devfs_pathpath(cdp->cdp_c.si_name, name) != 0)
                        return (1);
                if (devfs_pathpath(name, cdp->cdp_c.si_name) != 0)
                        return (1);
        }
        if (devfs_dir_find(name) != 0)
                return (1);

        return (0);
}

void
devfs_free(struct cdev *cdev)
{
        struct cdev_priv *cdp;

        cdp = cdev2priv(cdev);
        KASSERT((cdp->cdp_flags & (CDP_ACTIVE | CDP_ON_ACTIVE_LIST)) == 0,
            ("%s: cdp %p (%s) still on active list",
            __func__, cdp, cdev->si_name));
        if (cdev->si_cred != NULL)
                crfree(cdev->si_cred);
        devfs_free_cdp_inode(cdp->cdp_inode);
        if (cdp->cdp_maxdirent > 0) 
                free(cdp->cdp_dirents, M_DEVFS2);
        mtx_destroy(&cdp->cdp_threadlock);
        free(cdp, M_CDEVP);
}

struct devfs_dirent *
devfs_find(struct devfs_dirent *dd, const char *name, int namelen, int type)
{
        struct devfs_dirent *de;

        TAILQ_FOREACH(de, &dd->de_dlist, de_list) {
                if (namelen != de->de_dirent->d_namlen)
                        continue;
                if (type != 0 && type != de->de_dirent->d_type)
                        continue;

                /*
                 * The race with finding non-active name is not
                 * completely closed by the check, but it is similar
                 * to the devfs_allocv() in making it unlikely enough.
                 */
                if (de->de_dirent->d_type == DT_CHR &&
                    (de->de_cdp->cdp_flags & CDP_ACTIVE) == 0)
                        continue;

                if (bcmp(name, de->de_dirent->d_name, namelen) != 0)
                        continue;
                break;
        }
        KASSERT(de == NULL || (de->de_flags & DE_DOOMED) == 0,
            ("devfs_find: returning a doomed entry"));
        return (de);
}

struct devfs_dirent *
devfs_newdirent(char *name, int namelen)
{
        int i;
        struct devfs_dirent *de;
        struct dirent d;

        d.d_namlen = namelen;
        i = sizeof(*de) + GENERIC_DIRSIZ(&d);
        de = malloc(i, M_DEVFS3, M_WAITOK | M_ZERO);
        de->de_dirent = (struct dirent *)(de + 1);
        de->de_dirent->d_namlen = namelen;
        de->de_dirent->d_reclen = GENERIC_DIRSIZ(&d);
        bcopy(name, de->de_dirent->d_name, namelen);
        dirent_terminate(de->de_dirent);
        vfs_timestamp(&de->de_ctime);
        de->de_mtime = de->de_atime = de->de_ctime;
        de->de_links = 1;
        de->de_holdcnt = 1;
#ifdef MAC
        mac_devfs_init(de);
#endif
        return (de);
}

struct devfs_dirent *
devfs_parent_dirent(struct devfs_dirent *de)
{

        if (de->de_dirent->d_type != DT_DIR)
                return (de->de_dir);

        if (de->de_flags & (DE_DOT | DE_DOTDOT))
                return (NULL);

        de = TAILQ_FIRST(&de->de_dlist);        /* "." */
        if (de == NULL)
                return (NULL);
        de = TAILQ_NEXT(de, de_list);           /* ".." */
        if (de == NULL)
                return (NULL);

        return (de->de_dir);
}

struct devfs_dirent *
devfs_vmkdir(struct devfs_mount *dmp, char *name, int namelen,
    struct devfs_dirent *dotdot, u_int inode)
{
        struct devfs_dirent *dd;
        struct devfs_dirent *de;

        /* Create the new directory */
        dd = devfs_newdirent(name, namelen);
        TAILQ_INIT(&dd->de_dlist);
        dd->de_dirent->d_type = DT_DIR;
        dd->de_mode = 0555;
        dd->de_links = 2;
        dd->de_dir = dd;
        if (inode != 0)
                dd->de_inode = inode;
        else
                dd->de_inode = alloc_unr(devfs_inos);

        /*
         * "." and ".." are always the two first entries in the
         * de_dlist list.
         *
         * Create the "." entry in the new directory.
         */
        de = devfs_newdirent(".", 1);
        de->de_dirent->d_type = DT_DIR;
        de->de_flags |= DE_DOT;
        TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
        de->de_dir = dd;

        /* Create the ".." entry in the new directory. */
        de = devfs_newdirent("..", 2);
        de->de_dirent->d_type = DT_DIR;
        de->de_flags |= DE_DOTDOT;
        TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
        if (dotdot == NULL) {
                de->de_dir = dd;
        } else {
                de->de_dir = dotdot;
                sx_assert(&dmp->dm_lock, SX_XLOCKED);
                TAILQ_INSERT_TAIL(&dotdot->de_dlist, dd, de_list);
                dotdot->de_links++;
                devfs_rules_apply(dmp, dd);
        }

#ifdef MAC
        mac_devfs_create_directory(dmp->dm_mount, name, namelen, dd);
#endif
        return (dd);
}

void
devfs_dirent_free(struct devfs_dirent *de)
{
        struct vnode *vp;

        vp = de->de_vnode;
        mtx_lock(&devfs_de_interlock);
        if (vp != NULL && vp->v_data == de)
                vp->v_data = NULL;
        mtx_unlock(&devfs_de_interlock);
        free(de, M_DEVFS3);
}

/*
 * Removes a directory if it is empty. Also empty parent directories are
 * removed recursively.
 */
static void
devfs_rmdir_empty(struct devfs_mount *dm, struct devfs_dirent *de)
{
        struct devfs_dirent *dd, *de_dot, *de_dotdot;

        sx_assert(&dm->dm_lock, SX_XLOCKED);

        for (;;) {
                KASSERT(de->de_dirent->d_type == DT_DIR,
                    ("devfs_rmdir_empty: de is not a directory"));

                if ((de->de_flags & DE_DOOMED) != 0 || de == dm->dm_rootdir)
                        return;

                de_dot = TAILQ_FIRST(&de->de_dlist);
                KASSERT(de_dot != NULL, ("devfs_rmdir_empty: . missing"));
                de_dotdot = TAILQ_NEXT(de_dot, de_list);
                KASSERT(de_dotdot != NULL, ("devfs_rmdir_empty: .. missing"));
                /* Return if the directory is not empty. */
                if (TAILQ_NEXT(de_dotdot, de_list) != NULL)
                        return;

                dd = devfs_parent_dirent(de);
                KASSERT(dd != NULL, ("devfs_rmdir_empty: NULL dd"));
                TAILQ_REMOVE(&de->de_dlist, de_dot, de_list);
                TAILQ_REMOVE(&de->de_dlist, de_dotdot, de_list);
                TAILQ_REMOVE(&dd->de_dlist, de, de_list);
                DEVFS_DE_HOLD(dd);
                devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
                devfs_delete(dm, de_dot, DEVFS_DEL_NORECURSE);
                devfs_delete(dm, de_dotdot, DEVFS_DEL_NORECURSE);
                if (DEVFS_DE_DROP(dd)) {
                        devfs_dirent_free(dd);
                        return;
                }

                de = dd;
        }
}

/*
 * The caller needs to hold the dm for the duration of the call since
 * dm->dm_lock may be temporary dropped.
 */
void
devfs_delete(struct devfs_mount *dm, struct devfs_dirent *de, int flags)
{
        struct devfs_dirent *dd;
        struct vnode *vp;

        KASSERT((de->de_flags & DE_DOOMED) == 0,
                ("devfs_delete doomed dirent"));
        de->de_flags |= DE_DOOMED;

        if ((flags & DEVFS_DEL_NORECURSE) == 0) {
                dd = devfs_parent_dirent(de);
                if (dd != NULL)
                        DEVFS_DE_HOLD(dd);
                if (de->de_flags & DE_USER) {
                        KASSERT(dd != NULL, ("devfs_delete: NULL dd"));
                        devfs_dir_unref_de(dm, dd);
                }
        } else
                dd = NULL;

        mtx_lock(&devfs_de_interlock);
        vp = de->de_vnode;
        if (vp != NULL) {
                vhold(vp);
                mtx_unlock(&devfs_de_interlock);
                sx_unlock(&dm->dm_lock);
                vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
                vgone(vp);
                VOP_UNLOCK(vp);
                vdrop(vp);
                sx_xlock(&dm->dm_lock);
        } else
                mtx_unlock(&devfs_de_interlock);
        if (de->de_symlink) {
                free(de->de_symlink, M_DEVFS);
                de->de_symlink = NULL;
        }
#ifdef MAC
        mac_devfs_destroy(de);
#endif
        if (de->de_inode > DEVFS_ROOTINO) {
                devfs_free_cdp_inode(de->de_inode);
                de->de_inode = 0;
        }
        if (DEVFS_DE_DROP(de))
                devfs_dirent_free(de);

        if (dd != NULL) {
                if (DEVFS_DE_DROP(dd))
                        devfs_dirent_free(dd);
                else
                        devfs_rmdir_empty(dm, dd);
        }
}

/*
 * Called on unmount.
 * Recursively removes the entire tree.
 * The caller needs to hold the dm for the duration of the call.
 */

static void
devfs_purge(struct devfs_mount *dm, struct devfs_dirent *dd)
{
        struct devfs_dirent *de;

        sx_assert(&dm->dm_lock, SX_XLOCKED);

        DEVFS_DE_HOLD(dd);
        for (;;) {
                /*
                 * Use TAILQ_LAST() to remove "." and ".." last.
                 * We might need ".." to resolve a path in
                 * devfs_dir_unref_de().
                 */
                de = TAILQ_LAST(&dd->de_dlist, devfs_dlist_head);
                if (de == NULL)
                        break;
                TAILQ_REMOVE(&dd->de_dlist, de, de_list);
                if (de->de_flags & DE_USER)
                        devfs_dir_unref_de(dm, dd);
                if (de->de_flags & (DE_DOT | DE_DOTDOT))
                        devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
                else if (de->de_dirent->d_type == DT_DIR)
                        devfs_purge(dm, de);
                else
                        devfs_delete(dm, de, DEVFS_DEL_NORECURSE);
        }
        if (DEVFS_DE_DROP(dd))
                devfs_dirent_free(dd);
        else if ((dd->de_flags & DE_DOOMED) == 0)
                devfs_delete(dm, dd, DEVFS_DEL_NORECURSE);
}

/*
 * Each cdev_priv has an array of pointers to devfs_dirent which is indexed
 * by the mount points dm_idx.
 * This function extends the array when necessary, taking into account that
 * the default array is 1 element and not malloc'ed.
 */
static void
devfs_metoo(struct cdev_priv *cdp, struct devfs_mount *dm)
{
        struct devfs_dirent **dep, **olddep;
        int siz;

        siz = (dm->dm_idx + 1) * sizeof *dep;
        dep = malloc(siz, M_DEVFS2, M_WAITOK | M_ZERO);
        dev_lock();
        if (dm->dm_idx <= cdp->cdp_maxdirent) {
                /* We got raced */
                dev_unlock();
                free(dep, M_DEVFS2);
                return;
        } 
        memcpy(dep, cdp->cdp_dirents, (cdp->cdp_maxdirent + 1) * sizeof *dep);
        olddep = cdp->cdp_maxdirent > 0 ? cdp->cdp_dirents : NULL;
        cdp->cdp_dirents = dep;
        /*
         * XXX: if malloc told us how much we actually got this could
         * XXX: be optimized.
         */
        cdp->cdp_maxdirent = dm->dm_idx;
        dev_unlock();
        free(olddep, M_DEVFS2);
}

/*
 * The caller needs to hold the dm for the duration of the call.
 */
static int
devfs_populate_loop(struct devfs_mount *dm, int cleanup)
{
        struct cdev_priv *cdp;
        struct devfs_dirent *de;
        struct devfs_dirent *dd, *dt;
        struct cdev *pdev;
        int de_flags, depth, j;
        char *q, *s;

        sx_assert(&dm->dm_lock, SX_XLOCKED);
        dev_lock();
        TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
                KASSERT(cdp->cdp_dirents != NULL, ("NULL cdp_dirents"));
                KASSERT((cdp->cdp_flags & CDP_ON_ACTIVE_LIST) != 0,
                    ("%s: cdp %p (%s) should not be on active list",
                    __func__, cdp, cdp->cdp_c.si_name));

                /*
                 * If we are unmounting, or the device has been destroyed,
                 * clean up our dirent.
                 */
                if ((cleanup || !(cdp->cdp_flags & CDP_ACTIVE)) &&
                    dm->dm_idx <= cdp->cdp_maxdirent &&
                    cdp->cdp_dirents[dm->dm_idx] != NULL) {
                        de = cdp->cdp_dirents[dm->dm_idx];
                        cdp->cdp_dirents[dm->dm_idx] = NULL;
                        KASSERT(cdp == de->de_cdp,
                            ("%s %d %s %p %p", __func__, __LINE__,
                            cdp->cdp_c.si_name, cdp, de->de_cdp));
                        KASSERT(de->de_dir != NULL, ("Null de->de_dir"));
                        dev_unlock();

                        TAILQ_REMOVE(&de->de_dir->de_dlist, de, de_list);
                        de->de_cdp = NULL;
                        de->de_inode = 0;
                        devfs_delete(dm, de, 0);
                        dev_lock();
                        cdp->cdp_inuse--;
                        dev_unlock();
                        return (1);
                }
                /*
                 * GC any lingering devices
                 */
                if (!(cdp->cdp_flags & CDP_ACTIVE)) {
                        if (cdp->cdp_inuse > 0)
                                continue;
                        cdp->cdp_flags &= ~CDP_ON_ACTIVE_LIST;
                        TAILQ_REMOVE(&cdevp_list, cdp, cdp_list);
                        dev_unlock();
                        dev_rel(&cdp->cdp_c);
                        return (1);
                }
                /*
                 * Don't create any new dirents if we are unmounting
                 */
                if (cleanup)
                        continue;
                KASSERT((cdp->cdp_flags & CDP_ACTIVE), ("Bogons, I tell ya'!"));

                if (dm->dm_idx <= cdp->cdp_maxdirent &&
                    cdp->cdp_dirents[dm->dm_idx] != NULL) {
                        de = cdp->cdp_dirents[dm->dm_idx];
                        KASSERT(cdp == de->de_cdp, ("inconsistent cdp"));
                        continue;
                }

                cdp->cdp_inuse++;
                dev_unlock();

                if (dm->dm_idx > cdp->cdp_maxdirent)
                        devfs_metoo(cdp, dm);

                dd = dm->dm_rootdir;
                s = cdp->cdp_c.si_name;
                for (;;) {
                        for (q = s; *q != '/' && *q != '\0'; q++)
                                continue;
                        if (*q != '/')
                                break;
                        de = devfs_find(dd, s, q - s, 0);
                        if (de == NULL)
                                de = devfs_vmkdir(dm, s, q - s, dd, 0);
                        else if (de->de_dirent->d_type == DT_LNK) {
                                de = devfs_find(dd, s, q - s, DT_DIR);
                                if (de == NULL)
                                        de = devfs_vmkdir(dm, s, q - s, dd, 0);
                                de->de_flags |= DE_COVERED;
                        }
                        s = q + 1;
                        dd = de;
                        KASSERT(dd->de_dirent->d_type == DT_DIR &&
                            (dd->de_flags & (DE_DOT | DE_DOTDOT)) == 0,
                            ("%s: invalid directory (si_name=%s)",
                            __func__, cdp->cdp_c.si_name));
                }
                de_flags = 0;
                de = devfs_find(dd, s, q - s, DT_LNK);
                if (de != NULL)
                        de_flags |= DE_COVERED;

                de = devfs_newdirent(s, q - s);
                if (cdp->cdp_c.si_flags & SI_ALIAS) {
                        de->de_uid = 0;
                        de->de_gid = 0;
                        de->de_mode = 0755;
                        de->de_dirent->d_type = DT_LNK;
                        pdev = cdp->cdp_c.si_parent;
                        dt = dd;
                        depth = 0;
                        while (dt != dm->dm_rootdir &&
                            (dt = devfs_parent_dirent(dt)) != NULL)
                                depth++;
                        j = depth * 3 + strlen(pdev->si_name) + 1;
                        de->de_symlink = malloc(j, M_DEVFS, M_WAITOK);
                        de->de_symlink[0] = 0;
                        while (depth-- > 0)
                                strcat(de->de_symlink, "../");
                        strcat(de->de_symlink, pdev->si_name);
                } else {
                        de->de_uid = cdp->cdp_c.si_uid;
                        de->de_gid = cdp->cdp_c.si_gid;
                        de->de_mode = cdp->cdp_c.si_mode;
                        de->de_dirent->d_type = DT_CHR;
                }
                de->de_flags |= de_flags;
                de->de_inode = cdp->cdp_inode;
                de->de_cdp = cdp;
#ifdef MAC
                mac_devfs_create_device(cdp->cdp_c.si_cred, dm->dm_mount,
                    &cdp->cdp_c, de);
#endif
                de->de_dir = dd;
                TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
                devfs_rules_apply(dm, de);
                dev_lock();
                /* XXX: could check that cdp is still active here */
                KASSERT(cdp->cdp_dirents[dm->dm_idx] == NULL,
                    ("%s %d\n", __func__, __LINE__));
                cdp->cdp_dirents[dm->dm_idx] = de;
                KASSERT(de->de_cdp != (void *)0xdeadc0de,
                    ("%s %d\n", __func__, __LINE__));
                dev_unlock();
                return (1);
        }
        dev_unlock();
        return (0);
}

int
devfs_populate_needed(struct devfs_mount *dm)
{

        return (dm->dm_generation != devfs_generation);
}

/*
 * The caller needs to hold the dm for the duration of the call.
 */
void
devfs_populate(struct devfs_mount *dm)
{
        unsigned gen;

        sx_assert(&dm->dm_lock, SX_XLOCKED);
        if (!devfs_populate_needed(dm))
                return;
        gen = devfs_generation;
        while (devfs_populate_loop(dm, 0))
                continue;
        dm->dm_generation = gen;
}

/*
 * The caller needs to hold the dm for the duration of the call.
 */
void
devfs_cleanup(struct devfs_mount *dm)
{

        sx_assert(&dm->dm_lock, SX_XLOCKED);
        while (devfs_populate_loop(dm, 1))
                continue;
        devfs_purge(dm, dm->dm_rootdir);
}

/*
 * devfs_create() and devfs_destroy() are called from kern_conf.c and
 * in both cases the devlock() mutex is held, so no further locking
 * is necessary and no sleeping allowed.
 */

void
devfs_create(struct cdev *dev)
{
        struct cdev_priv *cdp;

        dev_lock_assert_locked();
        cdp = cdev2priv(dev);
        KASSERT((cdp->cdp_flags & CDP_ON_ACTIVE_LIST) == 0,
            ("%s: cdp %p (%s) already on active list",
            __func__, cdp, dev->si_name));
        cdp->cdp_flags |= (CDP_ACTIVE | CDP_ON_ACTIVE_LIST);
        cdp->cdp_inode = alloc_unrl(devfs_inos);
        dev_refl(dev);
        TAILQ_INSERT_TAIL(&cdevp_list, cdp, cdp_list);
        devfs_generation++;
}

void
devfs_destroy(struct cdev *dev)
{
        struct cdev_priv *cdp;

        dev_lock_assert_locked();
        cdp = cdev2priv(dev);
        cdp->cdp_flags &= ~CDP_ACTIVE;
        devfs_generation++;
}

ino_t
devfs_alloc_cdp_inode(void)
{

        return (alloc_unr(devfs_inos));
}

void
devfs_free_cdp_inode(ino_t ino)
{

        if (ino > 0)
                free_unr(devfs_inos, ino);
}

static void
devfs_devs_init(void *junk __unused)
{

        devfs_inos = new_unrhdr(DEVFS_ROOTINO + 1, INT_MAX, &devmtx);
}

SYSINIT(devfs_devs, SI_SUB_DEVFS, SI_ORDER_FIRST, devfs_devs_init, NULL);