sys/kern/vfs_syscalls.c

root/sys/kern/vfs_syscalls.c
/*      $OpenBSD: vfs_syscalls.c,v 1.380 2026/03/09 02:44:04 deraadt Exp $      */
/*      $NetBSD: vfs_syscalls.c,v 1.71 1996/04/23 10:29:02 mycroft Exp $        */

/*
 * Copyright (c) 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * 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.
 *
 *      @(#)vfs_syscalls.c      8.28 (Berkeley) 12/10/94
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/namei.h>
#include <sys/filedesc.h>
#include <sys/conf.h>
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/lock.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/proc.h>
#include <sys/pledge.h>
#include <sys/uio.h>
#include <sys/malloc.h>
#include <sys/pool.h>
#include <sys/ktrace.h>
#include <sys/unistd.h>
#include <sys/specdev.h>
#include <sys/resourcevar.h>
#include <sys/signalvar.h>

#include <sys/syscallargs.h>

static int change_dir(struct nameidata *, struct proc *);

void checkdirs(struct vnode *);

int copyout_statfs(struct statfs *, void *, struct proc *);

int doopenat(struct proc *, int, const char *, int, mode_t, int, register_t *);
int domknodat(struct proc *, int, const char *, mode_t, dev_t);
int dolinkat(struct proc *, int, const char *, int, const char *, int);
int dosymlinkat(struct proc *, const char *, int, const char *);
int dounlinkat(struct proc *, int, const char *, int);
int dofaccessat(struct proc *, int, const char *, int, int);
int dofstatat(struct proc *, int, const char *, struct stat *, int);
int dopathconfat(struct proc *, int, const char *, int, int, register_t *);
int doreadlinkat(struct proc *, int, const char *, char *, size_t,
    register_t *);
int dochflagsat(struct proc *, int, const char *, u_int, int);
int dovchflags(struct proc *, struct vnode *, u_int);
int dofchmodat(struct proc *, int, const char *, mode_t, int);
int dofchownat(struct proc *, int, const char *, uid_t, gid_t, int);
int dorenameat(struct proc *, int, const char *, int, const char *);
int domkdirat(struct proc *, int, const char *, mode_t);
int doutimensat(struct proc *, int, const char *, struct timespec [2], int);
int dovutimens(struct proc *, struct vnode *, struct timespec [2]);
int dofutimens(struct proc *, int, struct timespec [2]);
int dounmount_leaf(struct mount *, int, struct proc *);

/*
 * Virtual File System System Calls
 */

/*
 * Mount a file system.
 */
int
sys_mount(struct proc *p, void *v, register_t *retval)
{
        struct sys_mount_args /* {
                syscallarg(const char *) type;
                syscallarg(const char *) path;
                syscallarg(int) flags;
                syscallarg(void *) data;
        } */ *uap = v;
        struct vnode *vp;
        struct mount *mp;
        int error, mntflag = 0;
        char fstypename[MFSNAMELEN];
        char fspath[MNAMELEN];
        struct nameidata nd;
        struct vfsconf *vfsp;
        int flags = SCARG(uap, flags);
        void *args = NULL;

        if ((error = suser(p)))
                return (error);

        /*
         * Mount points must fit in MNAMELEN, not MAXPATHLEN.
         */
        error = copyinstr(SCARG(uap, path), fspath, MNAMELEN, NULL);
        if (error)
                return(error);

        /*
         * Get vnode to be covered
         */
        NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, fspath, p);
        if ((error = namei(&nd)) != 0)
                goto fail;
        vp = nd.ni_vp;
        if (flags & MNT_UPDATE) {
                if ((vp->v_flag & VROOT) == 0) {
                        vput(vp);
                        error = EINVAL;
                        goto fail;
                }
                mp = vp->v_mount;
                vfsp = mp->mnt_vfc;

                args = malloc(vfsp->vfc_datasize, M_TEMP, M_WAITOK | M_ZERO);
                error = copyin(SCARG(uap, data), args, vfsp->vfc_datasize);
                if (error) {
                        vput(vp);
                        goto fail;
                }

                mntflag = mp->mnt_flag;
                /*
                 * We only allow the filesystem to be reloaded if it
                 * is currently mounted read-only.
                 */
                if ((flags & MNT_RELOAD) &&
                    ((mp->mnt_flag & MNT_RDONLY) == 0)) {
                        vput(vp);
                        error = EOPNOTSUPP;     /* Needs translation */
                        goto fail;
                }

                if ((error = vfs_busy(mp, VB_READ|VB_NOWAIT)) != 0) {
                        vput(vp);
                        goto fail;
                }
                mp->mnt_flag |= flags & (MNT_RELOAD | MNT_UPDATE);
                goto update;
        }
        /*
         * Do not allow disabling of permission checks unless exec and access to
         * device files is disabled too.
         */
        if ((flags & MNT_NOPERM) &&
            (flags & (MNT_NODEV | MNT_NOEXEC)) != (MNT_NODEV | MNT_NOEXEC)) {
                vput(vp);
                error = EPERM;
                goto fail;
        }
        if ((error = vinvalbuf(vp, V_SAVE, p->p_ucred, p, 0, INFSLP)) != 0) {
                vput(vp);
                goto fail;
        }
        if (vp->v_type != VDIR) {
                vput(vp);
                goto fail;
        }
        error = copyinstr(SCARG(uap, type), fstypename, MFSNAMELEN, NULL);
        if (error) {
                vput(vp);
                goto fail;
        }
        vfsp = vfs_byname(fstypename);
        if (vfsp == NULL) {
                vput(vp);
                error = EOPNOTSUPP;
                goto fail;
        }

        args = malloc(vfsp->vfc_datasize, M_TEMP, M_WAITOK | M_ZERO);
        error = copyin(SCARG(uap, data), args, vfsp->vfc_datasize);
        if (error) {
                vput(vp);
                goto fail;
        }

        if (vp->v_mountedhere != NULL) {
                vput(vp);
                error = EBUSY;
                goto fail;
        }

        /*
         * Allocate and initialize the file system.
         */
        mp = vfs_mount_alloc(vp, vfsp);
        mp->mnt_stat.f_owner = p->p_ucred->cr_uid;

update:
        /* Ensure that the parent mountpoint does not get unmounted. */
        error = vfs_busy(vp->v_mount, VB_READ|VB_NOWAIT|VB_DUPOK);
        if (error) {
                if (mp->mnt_flag & MNT_UPDATE) {
                        mp->mnt_flag = mntflag;
                        vfs_unbusy(mp);
                } else {
                        vfs_unbusy(mp);
                        vfs_mount_free(mp);
                }
                vput(vp);
                goto fail;
        }

        /*
         * Set the mount level flags.
         */
        if (flags & MNT_RDONLY)
                mp->mnt_flag |= MNT_RDONLY;
        else if (mp->mnt_flag & MNT_RDONLY)
                mp->mnt_flag |= MNT_WANTRDWR;
        mp->mnt_flag &=~ (MNT_NOSUID | MNT_NOEXEC | MNT_WXALLOWED | MNT_NODEV |
            MNT_SYNCHRONOUS | MNT_ASYNC | MNT_NOATIME | MNT_NOPERM | MNT_FORCE);
        mp->mnt_flag |= flags & (MNT_NOSUID | MNT_NOEXEC | MNT_WXALLOWED |
            MNT_NODEV | MNT_SYNCHRONOUS | MNT_ASYNC | MNT_NOATIME | MNT_NOPERM |
            MNT_FORCE);
        /*
         * Mount the filesystem.
         */
        error = VFS_MOUNT(mp, fspath, args, &nd, p);
        if (!error) {
                mp->mnt_stat.f_ctime = gettime();
        }
        if (mp->mnt_flag & MNT_UPDATE) {
                vfs_unbusy(vp->v_mount);
                vput(vp);
                if (mp->mnt_flag & MNT_WANTRDWR)
                        mp->mnt_flag &= ~MNT_RDONLY;
                mp->mnt_flag &= ~MNT_OP_FLAGS;
                if (error)
                        mp->mnt_flag = mntflag;

                if ((mp->mnt_flag & MNT_RDONLY) == 0) {
                        if (mp->mnt_syncer == NULL)
                                error = vfs_allocate_syncvnode(mp);
                } else {
                        if (mp->mnt_syncer != NULL)
                                vgone(mp->mnt_syncer);
                        mp->mnt_syncer = NULL;
                }

                vfs_unbusy(mp);
                goto fail;
        }

        mp->mnt_flag &= ~MNT_OP_FLAGS;
        vp->v_mountedhere = mp;

        /*
         * Put the new filesystem on the mount list after root.
         */
        cache_purge(vp);
        if (!error) {
                TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
                checkdirs(vp);
                vfs_unbusy(vp->v_mount);
                VOP_UNLOCK(vp);
                if ((mp->mnt_flag & MNT_RDONLY) == 0)
                        error = vfs_allocate_syncvnode(mp);
                vfs_unbusy(mp);
                (void) VFS_STATFS(mp, &mp->mnt_stat, p);
                if ((error = VFS_START(mp, 0, p)) != 0)
                        vrele(vp);
        } else {
                mp->mnt_vnodecovered->v_mountedhere = NULL;
                vfs_unbusy(mp);
                vfs_mount_free(mp);
                vfs_unbusy(vp->v_mount);
                vput(vp);
        }
fail:
        if (args)
                free(args, M_TEMP, vfsp->vfc_datasize);
        return (error);
}

/*
 * Scan all active processes to see if any of them have a current
 * or root directory onto which the new filesystem has just been
 * mounted. If so, replace them with the new mount point, keeping
 * track of how many were replaced.  That's the number of references
 * the old vnode had that we've replaced, so finish by vrele()'ing
 * it that many times.  This puts off any possible sleeping until
 * we've finished walking the allprocess list.
 */
void
checkdirs(struct vnode *olddp)
{
        struct filedesc *fdp;
        struct vnode *newdp;
        struct process *pr;
        u_int  free_count = 0;

        if (olddp->v_usecount == 1)
                return;
        if (VFS_ROOT(olddp->v_mountedhere, &newdp))
                panic("mount: lost mount");
        LIST_FOREACH(pr, &allprocess, ps_list) {
                fdp = pr->ps_fd;
                if (fdp->fd_cdir == olddp) {
                        free_count++;
                        vref(newdp);
                        fdp->fd_cdir = newdp;
                }
                if (fdp->fd_rdir == olddp) {
                        free_count++;
                        vref(newdp);
                        fdp->fd_rdir = newdp;
                }
        }
        if (rootvnode == olddp) {
                free_count++;
                vref(newdp);
                rootvnode = newdp;
        }
        while (free_count-- > 0)
                vrele(olddp);
        vput(newdp);
}

/*
 * Unmount a file system.
 *
 * Note: unmount takes a path to the vnode mounted on as argument,
 * not special file (as before).
 */
int
sys_unmount(struct proc *p, void *v, register_t *retval)
{
        struct sys_unmount_args /* {
                syscallarg(const char *) path;
                syscallarg(int) flags;
        } */ *uap = v;
        struct vnode *vp;
        struct mount *mp;
        int error;
        struct nameidata nd;

        if ((error = suser(p)) != 0)
                return (error);

        NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_USERSPACE,
            SCARG(uap, path), p);
        if ((error = namei(&nd)) != 0)
                return (error);
        vp = nd.ni_vp;
        mp = vp->v_mount;

        /*
         * Don't allow unmounting the root file system.
         */
        if (mp->mnt_flag & MNT_ROOTFS) {
                vput(vp);
                return (EINVAL);
        }

        /*
         * Must be the root of the filesystem
         */
        if ((vp->v_flag & VROOT) == 0) {
                vput(vp);
                return (EINVAL);
        }
        vput(vp);

        if (vfs_busy(mp, VB_WRITE|VB_WAIT))
                return (EBUSY);

        return (dounmount(mp, SCARG(uap, flags) & MNT_FORCE, p));
}

/*
 * Do the actual file system unmount.
 */
int
dounmount(struct mount *mp, int flags, struct proc *p)
{
        SLIST_HEAD(, mount) mplist;
        struct mount *nmp;
        int error;

        SLIST_INIT(&mplist);
        SLIST_INSERT_HEAD(&mplist, mp, mnt_dounmount);

        /*
         * Collect nested mount points. This takes advantage of the mount list
         * being ordered - nested mount points come after their parent.
         */
        while ((mp = TAILQ_NEXT(mp, mnt_list)) != NULL) {
                SLIST_FOREACH(nmp, &mplist, mnt_dounmount) {
                        if (mp->mnt_vnodecovered == NULL ||
                            mp->mnt_vnodecovered->v_mount != nmp)
                                continue;

                        if ((flags & MNT_FORCE) == 0) {
                                error = EBUSY;
                                goto err;
                        }
                        error = vfs_busy(mp, VB_WRITE|VB_WAIT|VB_DUPOK);
                        if (error) {
                                if ((flags & MNT_DOOMED)) {
                                        /*
                                         * If the mount point was busy due to
                                         * being unmounted, it has been removed
                                         * from the mount list already.
                                         * Restart the iteration from the last
                                         * collected busy entry.
                                         */
                                        mp = SLIST_FIRST(&mplist);
                                        break;
                                }
                                goto err;
                        }
                        SLIST_INSERT_HEAD(&mplist, mp, mnt_dounmount);
                        break;
                }
        }

        /*
         * Nested mount points cannot appear during this loop as mounting
         * requires a read lock for the parent mount point.
         */
        while ((mp = SLIST_FIRST(&mplist)) != NULL) {
                SLIST_REMOVE(&mplist, mp, mount, mnt_dounmount);
                error = dounmount_leaf(mp, flags, p);
                if (error)
                        goto err;
        }
        return (0);

err:
        while ((mp = SLIST_FIRST(&mplist)) != NULL) {
                SLIST_REMOVE(&mplist, mp, mount, mnt_dounmount);
                vfs_unbusy(mp);
        }
        return (error);
}

int
dounmount_leaf(struct mount *mp, int flags, struct proc *p)
{
        struct vnode *coveredvp;
        struct vnode *vp, *nvp;
        int error;
        int hadsyncer = 0;

        mp->mnt_flag &=~ MNT_ASYNC;
        cache_purgevfs(mp);     /* remove cache entries for this file sys */
        if (mp->mnt_syncer != NULL) {
                hadsyncer = 1;
                vgone(mp->mnt_syncer);
                mp->mnt_syncer = NULL;
        }

        /*
         * Before calling file system unmount, make sure
         * all unveils to vnodes in here are dropped.
         */
        TAILQ_FOREACH_SAFE(vp , &mp->mnt_vnodelist, v_mntvnodes, nvp) {
                unveil_removevnode(vp);
        }

        if (((mp->mnt_flag & MNT_RDONLY) ||
            (error = VFS_SYNC(mp, MNT_WAIT, 0, p->p_ucred, p)) == 0) ||
            (flags & MNT_FORCE))
                error = VFS_UNMOUNT(mp, flags, p);

        if (error && !(flags & MNT_DOOMED)) {
                if ((mp->mnt_flag & MNT_RDONLY) == 0 && hadsyncer)
                        (void) vfs_allocate_syncvnode(mp);
                vfs_unbusy(mp);
                return (error);
        }

        TAILQ_REMOVE(&mountlist, mp, mnt_list);
        if ((coveredvp = mp->mnt_vnodecovered) != NULL) {
                coveredvp->v_mountedhere = NULL;
                vrele(coveredvp);
        }

        if (!TAILQ_EMPTY(&mp->mnt_vnodelist))
                panic("unmount: dangling vnode");

        vfs_unbusy(mp);
        vfs_mount_free(mp);

        return (0);
}

/*
 * Sync each mounted filesystem.
 */
int
sys_sync(struct proc *p, void *v, register_t *retval)
{
        struct mount *mp;
        int asyncflag;

        TAILQ_FOREACH_REVERSE(mp, &mountlist, mntlist, mnt_list) {
                if (vfs_busy(mp, VB_READ|VB_NOWAIT))
                        continue;
                if ((mp->mnt_flag & MNT_RDONLY) == 0) {
                        asyncflag = mp->mnt_flag & MNT_ASYNC;
                        mp->mnt_flag &= ~MNT_ASYNC;
                        uvm_vnp_sync(mp);
                        VFS_SYNC(mp, MNT_NOWAIT, 0, p->p_ucred, p);
                        if (asyncflag)
                                mp->mnt_flag |= MNT_ASYNC;
                }
                vfs_unbusy(mp);
        }

        return (0);
}

/*
 * Change filesystem quotas.
 */
int
sys_quotactl(struct proc *p, void *v, register_t *retval)
{
        struct sys_quotactl_args /* {
                syscallarg(const char *) path;
                syscallarg(int) cmd;
                syscallarg(int) uid;
                syscallarg(char *) arg;
        } */ *uap = v;
        struct mount *mp;
        int error;
        struct nameidata nd;

        NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
        if ((error = namei(&nd)) != 0)
                return (error);
        mp = nd.ni_vp->v_mount;
        vrele(nd.ni_vp);
        return (VFS_QUOTACTL(mp, SCARG(uap, cmd), SCARG(uap, uid),
            SCARG(uap, arg), p));
}

int
copyout_statfs(struct statfs *sp, void *uaddr, struct proc *p)
{
        size_t co_sz1 = offsetof(struct statfs, f_fsid);
        size_t co_off2 = co_sz1 + sizeof(fsid_t);
        size_t co_sz2 = sizeof(struct statfs) - co_off2;
        char *s, *d;
        int error;

        /* Don't let non-root see filesystem id (for NFS security) */
        if (suser(p)) {
                fsid_t fsid;

                s = (char *)sp;
                d = (char *)uaddr;

                memset(&fsid, 0, sizeof(fsid));

                if ((error = copyout(s, d, co_sz1)) != 0)
                        return (error);
                if ((error = copyout(&fsid, d + co_sz1, sizeof(fsid))) != 0)
                        return (error);
                return (copyout(s + co_off2, d + co_off2, co_sz2));
        }

        return (copyout(sp, uaddr, sizeof(*sp)));
}

/*
 * Get filesystem statistics.
 */
int
sys_statfs(struct proc *p, void *v, register_t *retval)
{
        struct sys_statfs_args /* {
                syscallarg(const char *) path;
                syscallarg(struct statfs *) buf;
        } */ *uap = v;
        struct mount *mp;
        struct statfs *sp;
        int error;
        struct nameidata nd;

        NDINIT(&nd, LOOKUP, FOLLOW | BYPASSUNVEIL, UIO_USERSPACE,
            SCARG(uap, path), p);
        nd.ni_pledge = PLEDGE_RPATH;
        nd.ni_unveil = UNVEIL_READ;
        if ((error = namei(&nd)) != 0)
                return (error);
        mp = nd.ni_vp->v_mount;
        sp = &mp->mnt_stat;
        vrele(nd.ni_vp);
        if ((error = VFS_STATFS(mp, sp, p)) != 0)
                return (error);
        sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;

        return (copyout_statfs(sp, SCARG(uap, buf), p));
}

/*
 * Get filesystem statistics.
 */
int
sys_fstatfs(struct proc *p, void *v, register_t *retval)
{
        struct sys_fstatfs_args /* {
                syscallarg(int) fd;
                syscallarg(struct statfs *) buf;
        } */ *uap = v;
        struct file *fp;
        struct mount *mp;
        struct statfs *sp;
        int error;

        if ((error = getvnode(p, SCARG(uap, fd), &fp)) != 0)
                return (error);
        mp = ((struct vnode *)fp->f_data)->v_mount;
        if (!mp) {
                FRELE(fp, p);
                return (ENOENT);
        }
        sp = &mp->mnt_stat;
        error = VFS_STATFS(mp, sp, p);
        FRELE(fp, p);
        if (error)
                return (error);
        sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;

        return (copyout_statfs(sp, SCARG(uap, buf), p));
}

/*
 * Get statistics on all filesystems.
 */
int
sys_getfsstat(struct proc *p, void *v, register_t *retval)
{
        struct sys_getfsstat_args /* {
                syscallarg(struct statfs *) buf;
                syscallarg(size_t) bufsize;
                syscallarg(int) flags;
        } */ *uap = v;
        struct mount *mp;
        struct statfs *sp;
        struct statfs *sfsp;
        size_t count, maxcount;
        int error, flags = SCARG(uap, flags);

        maxcount = SCARG(uap, bufsize) / sizeof(struct statfs);
        sfsp = SCARG(uap, buf);
        count = 0;

        TAILQ_FOREACH(mp, &mountlist, mnt_list) {
                if (vfs_busy(mp, VB_READ|VB_NOWAIT))
                        continue;
                if (sfsp && count < maxcount) {
                        sp = &mp->mnt_stat;

                        /* Refresh stats unless MNT_NOWAIT is specified */
                        if (flags != MNT_NOWAIT &&
                            flags != MNT_LAZY &&
                            (flags == MNT_WAIT ||
                            flags == 0) &&
                            (error = VFS_STATFS(mp, sp, p))) {
                                vfs_unbusy(mp);
                                continue;
                        }

                        sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
                        error = (copyout_statfs(sp, sfsp, p));
                        if (error) {
                                vfs_unbusy(mp);
                                return (error);
                        }
                        sfsp++;
                }
                count++;
                vfs_unbusy(mp);
        }

        if (sfsp && count > maxcount)
                *retval = maxcount;
        else
                *retval = count;

        return (0);
}

/*
 * Change current working directory to a given file descriptor.
 */
int
sys_fchdir(struct proc *p, void *v, register_t *retval)
{
        struct sys_fchdir_args /* {
                syscallarg(int) fd;
        } */ *uap = v;
        struct filedesc *fdp = p->p_fd;
        struct vnode *vp, *tdp, *old_cdir;
        struct mount *mp;
        struct file *fp;
        int error;

        if ((fp = fd_getfile(fdp, SCARG(uap, fd))) == NULL)
                return (EBADF);
        vp = fp->f_data;
        if (fp->f_type != DTYPE_VNODE || vp->v_type != VDIR) {
                FRELE(fp, p);
                return (ENOTDIR);
        }
        vref(vp);
        FRELE(fp, p);
        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
        error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p);

        while (!error && (mp = vp->v_mountedhere) != NULL) {
                if (vfs_busy(mp, VB_READ|VB_WAIT))
                        continue;
                error = VFS_ROOT(mp, &tdp);
                vfs_unbusy(mp);
                if (error)
                        break;
                vput(vp);
                vp = tdp;
        }
        if (error) {
                vput(vp);
                return (error);
        }
        VOP_UNLOCK(vp);
        old_cdir = fdp->fd_cdir;
        fdp->fd_cdir = vp;
        vrele(old_cdir);
        return (0);
}

/*
 * Change current working directory (``.'').
 */
int
sys_chdir(struct proc *p, void *v, register_t *retval)
{
        struct sys_chdir_args /* {
                syscallarg(const char *) path;
        } */ *uap = v;
        struct filedesc *fdp = p->p_fd;
        struct vnode *old_cdir;
        int error;
        struct nameidata nd;

        NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_USERSPACE,
            SCARG(uap, path), p);
        nd.ni_pledge = PLEDGE_RPATH;
        nd.ni_unveil = UNVEIL_READ;
        if ((error = change_dir(&nd, p)) != 0)
                return (error);
        old_cdir = fdp->fd_cdir;
        fdp->fd_cdir = nd.ni_vp;
        vrele(old_cdir);
        return (0);
}

/*
 * Change notion of root (``/'') directory.
 */
int
sys_chroot(struct proc *p, void *v, register_t *retval)
{
        struct sys_chroot_args /* {
                syscallarg(const char *) path;
        } */ *uap = v;
        struct filedesc *fdp = p->p_fd;
        struct vnode *old_cdir, *old_rdir;
        int error;
        struct nameidata nd;

        if ((error = suser(p)) != 0)
                return (error);
        NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_USERSPACE,
            SCARG(uap, path), p);
        if ((error = change_dir(&nd, p)) != 0)
                return (error);
        if (fdp->fd_rdir != NULL) {
                /*
                 * A chroot() done inside a changed root environment does
                 * an automatic chdir to avoid the out-of-tree experience.
                 */
                vref(nd.ni_vp);
                old_rdir = fdp->fd_rdir;
                old_cdir = fdp->fd_cdir;
                fdp->fd_rdir = fdp->fd_cdir = nd.ni_vp;
                vrele(old_rdir);
                vrele(old_cdir);
        } else
                fdp->fd_rdir = nd.ni_vp;
        atomic_setbits_int(&p->p_p->ps_flags, PS_CHROOT);
        return (0);
}

/*
 * Common routine for chroot and chdir.
 */
static int
change_dir(struct nameidata *ndp, struct proc *p)
{
        struct vnode *vp;
        int error;

        if ((error = namei(ndp)) != 0)
                return (error);
        vp = ndp->ni_vp;
        if (vp->v_type != VDIR)
                error = ENOTDIR;
        else
                error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p);
        if (error)
                vput(vp);
        else
                VOP_UNLOCK(vp);
        return (error);
}

int
sys___realpath(struct proc *p, void *v, register_t *retval)
{
        struct sys___realpath_args /* {
                syscallarg(const char *) pathname;
                syscallarg(char *) resolved;
        } */ *uap = v;
        char *pathname;
        char *rpbuf;
        struct nameidata nd;
        size_t pathlen;
        int error = 0;

        if (SCARG(uap, pathname) == NULL)
                return (EINVAL);

        pathname = pool_get(&namei_pool, PR_WAITOK);
        rpbuf = pool_get(&namei_pool, PR_WAITOK);

        if ((error = copyinstr(SCARG(uap, pathname), pathname, MAXPATHLEN,
            &pathlen)))
                goto end;

        if (pathlen == 1) { /* empty string "" */
                error = ENOENT;
                goto end;
        }
        if (pathlen < 2) {
                error = EINVAL;
                goto end;
        }

        /* Get cwd for relative path if needed, prepend to rpbuf */
        rpbuf[0] = '\0';
        if (pathname[0] != '/') {
                int cwdlen = MAXPATHLEN * 4; /* for vfs_getcwd_common */
                char *cwdbuf, *bp;

                cwdbuf = malloc(cwdlen, M_TEMP, M_WAITOK);

                /* vfs_getcwd_common fills this in backwards */
                bp = &cwdbuf[cwdlen - 1];
                *bp = '\0';

                KERNEL_LOCK();
                error = vfs_getcwd_common(p->p_fd->fd_cdir, NULL, &bp, cwdbuf,
                    cwdlen/2, GETCWD_CHECK_ACCESS, p);
                KERNEL_UNLOCK();

                if (error) {
                        free(cwdbuf, M_TEMP, cwdlen);
                        goto end;
                }

                if (strlcpy(rpbuf, bp, MAXPATHLEN) >= MAXPATHLEN) {
                        free(cwdbuf, M_TEMP, cwdlen);
                        error = ENAMETOOLONG;
                        goto end;
                }

                free(cwdbuf, M_TEMP, cwdlen);
        }

        NDINIT(&nd, LOOKUP, FOLLOW | SAVENAME | REALPATH, UIO_SYSSPACE,
            pathname, p);

        nd.ni_cnd.cn_rpbuf = rpbuf;
        nd.ni_cnd.cn_rpi = strlen(rpbuf);

        nd.ni_pledge = PLEDGE_RPATH;
        nd.ni_unveil = UNVEIL_READ;
        KERNEL_LOCK();
        if ((error = namei(&nd)) != 0) {
                KERNEL_UNLOCK();
                goto end;
        }

        /* release reference from namei */
        if (nd.ni_vp)
                vrele(nd.ni_vp);
        KERNEL_UNLOCK();

        error = copyoutstr(nd.ni_cnd.cn_rpbuf, SCARG(uap, resolved),
            MAXPATHLEN, NULL);

#ifdef KTRACE
        if (KTRPOINT(p, KTR_NAMEI))
                ktrnamei(p, nd.ni_cnd.cn_rpbuf);
#endif
        pool_put(&namei_pool, nd.ni_cnd.cn_pnbuf);
end:
        pool_put(&namei_pool, rpbuf);
        pool_put(&namei_pool, pathname);
        return (error);
}

int
sys_unveil(struct proc *p, void *v, register_t *retval)
{
        struct sys_unveil_args /* {
                syscallarg(const char *) path;
                syscallarg(const char *) permissions;
        } */ *uap = v;
        struct process *pr = p->p_p;
        char *pathname, *c;
        struct nameidata nd;
        size_t pathlen;
        char permissions[5];
        int error, allow;

        if (SCARG(uap, path) == NULL && SCARG(uap, permissions) == NULL) {
                pr->ps_uvdone = 1;
                return (0);
        }

        if (pr->ps_uvdone != 0)
                return EPERM;

        error = copyinstr(SCARG(uap, permissions), permissions,
            sizeof(permissions), NULL);
        if (error)
                return (error);

        /*
         * System calls in other threads may sleep between unveil
         * datastructure inspections -- this is the simplest way to
         * provide consistency 
         */
        single_thread_set(p, SINGLE_UNWIND);

        pathname = pool_get(&namei_pool, PR_WAITOK);
        error = copyinstr(SCARG(uap, path), pathname, MAXPATHLEN, &pathlen);
        if (error)
                goto end;

#ifdef KTRACE
        if (KTRPOINT(p, KTR_STRUCT))
                ktrstruct(p, "unveil", permissions, strlen(permissions));
#endif
        if (pathlen < 2) {
                error = EINVAL;
                goto end;
        }

        /* find root "/" or "//" */
        for (c = pathname; *c != '\0'; c++) {
                if (*c != '/')
                        break;
        }
        if (*c == '\0')
                /* root directory */
                NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | SAVENAME,
                    UIO_SYSSPACE, pathname, p);
        else
                NDINIT(&nd, CREATE, FOLLOW | LOCKLEAF | LOCKPARENT | SAVENAME,
                    UIO_SYSSPACE, pathname, p);

        nd.ni_pledge = PLEDGE_UNVEIL;
        if ((error = namei(&nd)) != 0)
                goto end;

        /*
         * XXX Any access to the file or directory will allow us to
         * pledge path it
         */
        allow = ((nd.ni_vp &&
            (VOP_ACCESS(nd.ni_vp, VREAD, p->p_ucred, p) == 0 ||
            VOP_ACCESS(nd.ni_vp, VWRITE, p->p_ucred, p) == 0 ||
            VOP_ACCESS(nd.ni_vp, VEXEC, p->p_ucred, p) == 0)) ||
            (nd.ni_dvp &&
            (VOP_ACCESS(nd.ni_dvp, VREAD, p->p_ucred, p) == 0 ||
            VOP_ACCESS(nd.ni_dvp, VWRITE, p->p_ucred, p) == 0 ||
            VOP_ACCESS(nd.ni_dvp, VEXEC, p->p_ucred, p) == 0)));

        /* release lock from namei, but keep ref */
        if (nd.ni_vp)
                VOP_UNLOCK(nd.ni_vp);
        if (nd.ni_dvp && nd.ni_dvp != nd.ni_vp)
                VOP_UNLOCK(nd.ni_dvp);

        if (allow)
                error = unveil_add(p, &nd, permissions);
        else
                error = EPERM;

        /* release vref from namei, but not vref from unveil_add */
        if (nd.ni_vp)
                vrele(nd.ni_vp);
        if (nd.ni_dvp)
                vrele(nd.ni_dvp);

        pool_put(&namei_pool, nd.ni_cnd.cn_pnbuf);
end:
        pool_put(&namei_pool, pathname);

        single_thread_clear(p);
        return (error);
}

/*
 * Check permissions, allocate an open file structure,
 * and call the device open routine if any.
 */
int
sys_open(struct proc *p, void *v, register_t *retval)
{
        struct sys_open_args /* {
                syscallarg(const char *) path;
                syscallarg(int) flags;
                syscallarg(mode_t) mode;
        } */ *uap = v;

        return (doopenat(p, AT_FDCWD, SCARG(uap, path), SCARG(uap, flags),
            SCARG(uap, mode), 0, retval));
}

/*
 * Check permissions, allocate an open file structure,
 * and call the device open routine if any.
 */
int
sys___pledge_open(struct proc *p, void *v, register_t *retval)
{
        struct sys___pledge_open_args /* {
                syscallarg(const char *) path;
                syscallarg(int) flags;
                syscallarg(mode_t) mode;
        } */ *uap = v;

        return (doopenat(p, AT_FDCWD, SCARG(uap, path), SCARG(uap, flags),
            SCARG(uap, mode), UNVEIL_PLEDGEOPEN, retval));
}

int
sys_openat(struct proc *p, void *v, register_t *retval)
{
        struct sys_openat_args /* {
                syscallarg(int) fd;
                syscallarg(const char *) path;
                syscallarg(int) flags;
                syscallarg(mode_t) mode;
        } */ *uap = v;

        return (doopenat(p, SCARG(uap, fd), SCARG(uap, path),
            SCARG(uap, flags), SCARG(uap, mode), 0, retval));
}

int
doopenat(struct proc *p, int fd, const char *path, int oflags, mode_t mode,
    int pledgeopen, register_t *retval)
{
        struct filedesc *fdp = p->p_fd;
        struct file *fp;
        struct vnode *vp;
        struct vattr vattr;
        int flags, fdflags, cmode;
        int type, indx, error, localtrunc = 0;
        struct flock lf;
        struct nameidata nd;
        uint64_t ni_pledge = 0;
        u_char ni_unveil = pledgeopen;

        if (oflags & (O_EXLOCK | O_SHLOCK)) {
                error = pledge_flock(p);
                if (error != 0)
                        return (error);
        }

        fdflags = ((oflags & O_CLOEXEC) ? UF_EXCLOSE : 0)
            | ((oflags & O_CLOFORK) ? UF_FORKCLOSE : 0);

        fdplock(fdp);
        if ((error = falloc(p, &fp, &indx)) != 0) {
                fdpunlock(fdp);
                return (error);
        }
        fdpunlock(fdp);

        flags = FFLAGS(oflags);
        if (flags & FREAD) {
                ni_pledge |= PLEDGE_RPATH;
                ni_unveil |= UNVEIL_READ;
        }
        if (flags & FWRITE) {
                ni_pledge |= PLEDGE_WPATH;
                ni_unveil |= UNVEIL_WRITE;
        }
        if (oflags & O_CREAT) {
                ni_pledge |= PLEDGE_CPATH;
                ni_unveil |= UNVEIL_CREATE;
        }

        cmode = ((mode &~ fdp->fd_cmask) & ALLPERMS) &~ S_ISTXT;
        if ((p->p_p->ps_flags & PS_PLEDGE))
                cmode &= ACCESSPERMS;
        NDINITAT(&nd, 0, 0, UIO_USERSPACE, fd, path, p);
        nd.ni_pledge = ni_pledge;
        nd.ni_unveil = ni_unveil;
        p->p_dupfd = -1;                        /* XXX check for fdopen */
        if ((flags & O_TRUNC) && (flags & (O_EXLOCK | O_SHLOCK))) {
                localtrunc = 1;
                flags &= ~O_TRUNC;      /* Must do truncate ourselves */
        }
        KERNEL_LOCK();
        if ((error = vn_open(&nd, flags, cmode)) != 0) {
                fdplock(fdp);
                if (error == ENODEV &&
                    p->p_dupfd >= 0 &&                  /* XXX from fdopen */
                    (error =
                        dupfdopen(p, indx, flags)) == 0) {
                        *retval = indx;
                        goto error;
                }
                if (error == ERESTART)
                        error = EINTR;
                fdremove(fdp, indx);
                goto error;
        }
        p->p_dupfd = 0;
        vp = nd.ni_vp;
        if (pledgeopen && vp->v_type != VCHR)
                fdflags |= UF_PLEDGEOPEN;
        fp->f_flag = flags & FMASK;
        fp->f_type = DTYPE_VNODE;
        fp->f_ops = &vnops;
        fp->f_data = vp;
        if (flags & (O_EXLOCK | O_SHLOCK)) {
                lf.l_whence = SEEK_SET;
                lf.l_start = 0;
                lf.l_len = 0;
                if (flags & O_EXLOCK)
                        lf.l_type = F_WRLCK;
                else
                        lf.l_type = F_RDLCK;
                type = F_FLOCK;
                if ((flags & FNONBLOCK) == 0)
                        type |= F_WAIT;
                VOP_UNLOCK(vp);
                error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type);
                if (error) {
                        fdplock(fdp);
                        /* closef will vn_close the file for us. */
                        fdremove(fdp, indx);
                        goto error;
                }
                vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
                atomic_setbits_int(&fp->f_iflags, FIF_HASLOCK);
        }
        if (localtrunc) {
                if ((fp->f_flag & FWRITE) == 0)
                        error = EACCES;
                else if (vp->v_mount && (vp->v_mount->mnt_flag & MNT_RDONLY))
                        error = EROFS;
                else if (vp->v_type == VDIR)
                        error = EISDIR;
                else if ((error = vn_writechk(vp)) == 0) {
                        vattr_null(&vattr);
                        vattr.va_size = 0;
                        error = VOP_SETATTR(vp, &vattr, fp->f_cred, p);
                }
                if (error) {
                        VOP_UNLOCK(vp);
                        fdplock(fdp);
                        /* closef will close the file for us. */
                        fdremove(fdp, indx);
                        goto error;
                }
        }
        VOP_UNLOCK(vp);
        KERNEL_UNLOCK();
        *retval = indx;
        fdplock(fdp);
        fdinsert(fdp, indx, fdflags, fp);
        fdpunlock(fdp);
        FRELE(fp, p);
        return (error);
error:
        KERNEL_UNLOCK();
        fdpunlock(fdp);
        closef(fp, p);
        return (error);
}

/*
 * Open a new created file (in /tmp) suitable for mmaping.
 */
int
sys___tmpfd(struct proc *p, void *v, register_t *retval)
{
        struct sys___tmpfd_args /* {
                syscallarg(int) flags;
        } */ *uap = v;
        struct filedesc *fdp = p->p_fd;
        struct file *fp;
        struct vnode *vp;
        int oflags = SCARG(uap, flags);
        int flags, fdflags, cmode;
        int indx, error;
        unsigned int i;
        struct nameidata nd;
        char path[64];
        static const char *letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_-";

        /* most flags are hardwired */
        oflags = O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW |
            (oflags & (O_CLOEXEC | O_CLOFORK));

        fdflags = ((oflags & O_CLOEXEC) ? UF_EXCLOSE : 0)
            | ((oflags & O_CLOFORK) ? UF_FORKCLOSE : 0);

        fdplock(fdp);
        if ((error = falloc(p, &fp, &indx)) != 0) {
                fdpunlock(fdp);
                return (error);
        }
        fdpunlock(fdp);

        flags = FFLAGS(oflags);

        arc4random_buf(path, sizeof(path));
        memcpy(path, "/tmp/", 5);
        for (i = 5; i < sizeof(path) - 1; i++)
                path[i] = letters[(unsigned char)path[i] & 63];
        path[sizeof(path)-1] = 0;

        cmode = 0600;
        NDINITAT(&nd, 0, KERNELPATH, UIO_SYSSPACE, AT_FDCWD, path, p);
        if ((error = vn_open(&nd, flags, cmode)) != 0) {
                if (error == ERESTART)
                        error = EINTR;
                fdplock(fdp);
                fdremove(fdp, indx);
                fdpunlock(fdp);
                closef(fp, p);
                return (error);
        }
        vp = nd.ni_vp;
        fp->f_flag = flags & FMASK;
        fp->f_type = DTYPE_VNODE;
        fp->f_ops = &vnops;
        fp->f_data = vp;
        VOP_UNLOCK(vp);
        *retval = indx;
        fdplock(fdp);
        fdinsert(fdp, indx, fdflags, fp);
        fdpunlock(fdp);
        FRELE(fp, p);

        /* unlink it */
        /* XXX
         * there is a wee race here, although it is mostly inconsequential.
         * perhaps someday we can create a file like object without a name...
         */
        NDINITAT(&nd, DELETE, KERNELPATH | LOCKPARENT | LOCKLEAF, UIO_SYSSPACE,
            AT_FDCWD, path, p);
        if ((error = namei(&nd)) != 0) {
                printf("can't unlink temp file! %d\n", error);
                error = 0;
        } else {
                vp = nd.ni_vp;
                uvm_vnp_uncache(vp);
                error = VOP_REMOVE(nd.ni_dvp, nd.ni_vp, &nd.ni_cnd);
                if (error) {
                        printf("error removing vop: %d\n", error);
                        error = 0;
                }
        }

        return (error);
}

/*
 * Get file handle system call
 */
int
sys_getfh(struct proc *p, void *v, register_t *retval)
{
        struct sys_getfh_args /* {
                syscallarg(const char *) fname;
                syscallarg(fhandle_t *) fhp;
        } */ *uap = v;
        struct vnode *vp;
        fhandle_t fh;
        int error;
        struct nameidata nd;

        /*
         * Must be super user
         */
        error = suser(p);
        if (error)
                return (error);
        NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_USERSPACE,
            SCARG(uap, fname), p);
        error = namei(&nd);
        if (error)
                return (error);
        vp = nd.ni_vp;
        memset(&fh, 0, sizeof(fh));
        fh.fh_fsid = vp->v_mount->mnt_stat.f_fsid;
        error = VFS_VPTOFH(vp, &fh.fh_fid);
        vput(vp);
        if (error)
                return (error);
        error = copyout(&fh, SCARG(uap, fhp), sizeof(fh));
        return (error);
}

/*
 * Open a file given a file handle.
 *
 * Check permissions, allocate an open file structure,
 * and call the device open routine if any.
 */
int
sys_fhopen(struct proc *p, void *v, register_t *retval)
{
        struct sys_fhopen_args /* {
                syscallarg(const fhandle_t *) fhp;
                syscallarg(int) flags;
        } */ *uap = v;
        struct filedesc *fdp = p->p_fd;
        struct file *fp;
        struct vnode *vp = NULL;
        struct mount *mp;
        struct ucred *cred = p->p_ucred;
        int flags, fdflags;
        int type, indx, error=0;
        struct flock lf;
        struct vattr va;
        fhandle_t fh;

        /*
         * Must be super user
         */
        if ((error = suser(p)))
                return (error);

        flags = FFLAGS(SCARG(uap, flags));
        if ((flags & (FREAD | FWRITE)) == 0)
                return (EINVAL);
        if ((flags & O_CREAT))
                return (EINVAL);

        fdflags = ((flags & O_CLOEXEC) ? UF_EXCLOSE : 0)
            | ((flags & O_CLOFORK) ? UF_FORKCLOSE : 0);

        fdplock(fdp);
        if ((error = falloc(p, &fp, &indx)) != 0) {
                fdpunlock(fdp);
                fp = NULL;
                goto bad;
        }
        fdpunlock(fdp);

        if ((error = copyin(SCARG(uap, fhp), &fh, sizeof(fhandle_t))) != 0)
                goto bad;

        if ((mp = vfs_getvfs(&fh.fh_fsid)) == NULL) {
                error = ESTALE;
                goto bad;
        }

        if ((error = VFS_FHTOVP(mp, &fh.fh_fid, &vp)) != 0) {
                vp = NULL;      /* most likely unnecessary sanity for bad: */
                goto bad;
        }

        /* Now do an effective vn_open */

        if (vp->v_type == VSOCK) {
                error = EOPNOTSUPP;
                goto bad;
        }
        if ((flags & O_DIRECTORY) && vp->v_type != VDIR) {
                error = ENOTDIR;
                goto bad;
        }
        if (flags & FREAD) {
                if ((error = VOP_ACCESS(vp, VREAD, cred, p)) != 0)
                        goto bad;
        }
        if (flags & (FWRITE | O_TRUNC)) {
                if (vp->v_type == VDIR) {
                        error = EISDIR;
                        goto bad;
                }
                if ((error = VOP_ACCESS(vp, VWRITE, cred, p)) != 0 ||
                    (error = vn_writechk(vp)) != 0)
                        goto bad;
        }
        if (flags & O_TRUNC) {
                vattr_null(&va);
                va.va_size = 0;
                if ((error = VOP_SETATTR(vp, &va, cred, p)) != 0)
                        goto bad;
        }
        if ((error = VOP_OPEN(vp, flags, cred, p)) != 0)
                goto bad;
        if (flags & FWRITE)
                vp->v_writecount++;

        /* done with modified vn_open, now finish what sys_open does. */

        fp->f_flag = flags & FMASK;
        fp->f_type = DTYPE_VNODE;
        fp->f_ops = &vnops;
        fp->f_data = vp;
        if (flags & (O_EXLOCK | O_SHLOCK)) {
                lf.l_whence = SEEK_SET;
                lf.l_start = 0;
                lf.l_len = 0;
                if (flags & O_EXLOCK)
                        lf.l_type = F_WRLCK;
                else
                        lf.l_type = F_RDLCK;
                type = F_FLOCK;
                if ((flags & FNONBLOCK) == 0)
                        type |= F_WAIT;
                VOP_UNLOCK(vp);
                error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type);
                if (error) {
                        vp = NULL;      /* closef will vn_close the file */
                        goto bad;
                }
                vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
                atomic_setbits_int(&fp->f_iflags, FIF_HASLOCK);
        }
        VOP_UNLOCK(vp);
        *retval = indx;
        fdplock(fdp);
        fdinsert(fdp, indx, fdflags, fp);
        fdpunlock(fdp);
        FRELE(fp, p);
        return (0);

bad:
        if (fp) {
                fdplock(fdp);
                fdremove(fdp, indx);
                fdpunlock(fdp);
                closef(fp, p);
                if (vp != NULL)
                        vput(vp);
        }
        return (error);
}

int
sys_fhstat(struct proc *p, void *v, register_t *retval)
{
        struct sys_fhstat_args /* {
                syscallarg(const fhandle_t *) fhp;
                syscallarg(struct stat *) sb;
        } */ *uap = v;
        struct stat sb;
        int error;
        fhandle_t fh;
        struct mount *mp;
        struct vnode *vp;

        /*
         * Must be super user
         */
        if ((error = suser(p)))
                return (error);

        if ((error = copyin(SCARG(uap, fhp), &fh, sizeof(fhandle_t))) != 0)
                return (error);

        if ((mp = vfs_getvfs(&fh.fh_fsid)) == NULL)
                return (ESTALE);
        if ((error = VFS_FHTOVP(mp, &fh.fh_fid, &vp)))
                return (error);
        error = vn_stat(vp, &sb, p);
        vput(vp);
        if (error)
                return (error);
        error = copyout(&sb, SCARG(uap, sb), sizeof(sb));
        return (error);
}

int
sys_fhstatfs(struct proc *p, void *v, register_t *retval)
{
        struct sys_fhstatfs_args /* {
                syscallarg(const fhandle_t *) fhp;
                syscallarg(struct statfs *) buf;
        } */ *uap = v;
        struct statfs *sp;
        fhandle_t fh;
        struct mount *mp;
        struct vnode *vp;
        int error;

        /*
         * Must be super user
         */
        if ((error = suser(p)))
                return (error);

        if ((error = copyin(SCARG(uap, fhp), &fh, sizeof(fhandle_t))) != 0)
                return (error);

        if ((mp = vfs_getvfs(&fh.fh_fsid)) == NULL)
                return (ESTALE);
        if ((error = VFS_FHTOVP(mp, &fh.fh_fid, &vp)))
                return (error);
        mp = vp->v_mount;
        sp = &mp->mnt_stat;
        vput(vp);
        if ((error = VFS_STATFS(mp, sp, p)) != 0)
                return (error);
        sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
        return (copyout(sp, SCARG(uap, buf), sizeof(*sp)));
}

/*
 * Create a special file or named pipe.
 */
int
sys_mknod(struct proc *p, void *v, register_t *retval)
{
        struct sys_mknod_args /* {
                syscallarg(const char *) path;
                syscallarg(mode_t) mode;
                syscallarg(int) dev;
        } */ *uap = v;

        return (domknodat(p, AT_FDCWD, SCARG(uap, path), SCARG(uap, mode),
            SCARG(uap, dev)));
}

int
sys_mknodat(struct proc *p, void *v, register_t *retval)
{
        struct sys_mknodat_args /* {
                syscallarg(int) fd;
                syscallarg(const char *) path;
                syscallarg(mode_t) mode;
                syscallarg(dev_t) dev;
        } */ *uap = v;

        return (domknodat(p, SCARG(uap, fd), SCARG(uap, path),
            SCARG(uap, mode), SCARG(uap, dev)));
}

int
domknodat(struct proc *p, int fd, const char *path, mode_t mode, dev_t dev)
{
        struct vnode *vp;
        struct vattr vattr;
        int error;
        struct nameidata nd;

        if (dev == VNOVAL)
                return (EINVAL);
        NDINITAT(&nd, CREATE, LOCKPARENT, UIO_USERSPACE, fd, path, p);
        nd.ni_pledge = PLEDGE_DPATH;
        nd.ni_unveil = UNVEIL_CREATE;
        if ((error = namei(&nd)) != 0)
                return (error);
        vp = nd.ni_vp;
        if (!S_ISFIFO(mode) || dev != 0) {
                if (!vnoperm(nd.ni_dvp) && (error = suser(p)) != 0)
                        goto out;
                if (p->p_fd->fd_rdir) {
                        error = EINVAL;
                        goto out;
                }
        }
        if (vp != NULL)
                error = EEXIST;
        else {
                vattr_null(&vattr);
                vattr.va_mode = (mode & ALLPERMS) &~ p->p_fd->fd_cmask;
                if ((p->p_p->ps_flags & PS_PLEDGE))
                        vattr.va_mode &= ACCESSPERMS;
                vattr.va_rdev = dev;

                switch (mode & S_IFMT) {
                case S_IFMT:    /* used by badsect to flag bad sectors */
                        vattr.va_type = VBAD;
                        break;
                case S_IFCHR:
                        vattr.va_type = VCHR;
                        break;
                case S_IFBLK:
                        vattr.va_type = VBLK;
                        break;
                case S_IFIFO:
#ifndef FIFO
                        error = EOPNOTSUPP;
                        break;
#else
                        if (dev == 0) {
                                vattr.va_type = VFIFO;
                                break;
                        }
                        /* FALLTHROUGH */
#endif /* FIFO */
                default:
                        error = EINVAL;
                        break;
                }
        }
out:
        if (!error) {
                error = VOP_MKNOD(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr);
                vput(nd.ni_dvp);
        } else {
                VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
                if (nd.ni_dvp == vp)
                        vrele(nd.ni_dvp);
                else
                        vput(nd.ni_dvp);
                if (vp)
                        vrele(vp);
        }
        return (error);
}

/*
 * Create a named pipe.
 */
int
sys_mkfifo(struct proc *p, void *v, register_t *retval)
{
        struct sys_mkfifo_args /* {
                syscallarg(const char *) path;
                syscallarg(mode_t) mode;
        } */ *uap = v;

        return (domknodat(p, AT_FDCWD, SCARG(uap, path),
            (SCARG(uap, mode) & ALLPERMS) | S_IFIFO, 0));
}

int
sys_mkfifoat(struct proc *p, void *v, register_t *retval)
{
        struct sys_mkfifoat_args /* {
                syscallarg(int) fd;
                syscallarg(const char *) path;
                syscallarg(mode_t) mode;
        } */ *uap = v;

        return (domknodat(p, SCARG(uap, fd), SCARG(uap, path),
            (SCARG(uap, mode) & ALLPERMS) | S_IFIFO, 0));
}

/*
 * Make a hard file link.
 */
int
sys_link(struct proc *p, void *v, register_t *retval)
{
        struct sys_link_args /* {
                syscallarg(const char *) path;
                syscallarg(const char *) link;
        } */ *uap = v;

        return (dolinkat(p, AT_FDCWD, SCARG(uap, path), AT_FDCWD,
            SCARG(uap, link), AT_SYMLINK_FOLLOW));
}

int
sys_linkat(struct proc *p, void *v, register_t *retval)
{
        struct sys_linkat_args /* {
                syscallarg(int) fd1;
                syscallarg(const char *) path1;
                syscallarg(int) fd2;
                syscallarg(const char *) path2;
                syscallarg(int) flag;
        } */ *uap = v;

        return (dolinkat(p, SCARG(uap, fd1), SCARG(uap, path1),
            SCARG(uap, fd2), SCARG(uap, path2), SCARG(uap, flag)));
}

int
dolinkat(struct proc *p, int fd1, const char *path1, int fd2,
    const char *path2, int flag)
{
        struct vnode *vp;
        struct nameidata nd;
        int error, follow;

        if (flag & ~AT_SYMLINK_FOLLOW)
                return (EINVAL);

        follow = (flag & AT_SYMLINK_FOLLOW) ? FOLLOW : NOFOLLOW;
        NDINITAT(&nd, LOOKUP, follow, UIO_USERSPACE, fd1, path1, p);
        nd.ni_pledge = PLEDGE_RPATH;
        nd.ni_unveil = UNVEIL_READ;
        if ((error = namei(&nd)) != 0)
                return (error);
        vp = nd.ni_vp;

        if (vp->v_type == VDIR) {
                error = EPERM;
                goto out;
        }

        NDINITAT(&nd, CREATE, LOCKPARENT, UIO_USERSPACE, fd2, path2, p);
        nd.ni_pledge = PLEDGE_CPATH;
        nd.ni_unveil = UNVEIL_CREATE;
        if ((error = namei(&nd)) != 0)
                goto out;
        if (nd.ni_vp) {
                VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
                if (nd.ni_dvp == nd.ni_vp)
                        vrele(nd.ni_dvp);
                else
                        vput(nd.ni_dvp);
                vrele(nd.ni_vp);
                error = EEXIST;
                goto out;
        }

        /* No cross-mount links! */
        if (nd.ni_dvp->v_mount != vp->v_mount) {
                VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
                vput(nd.ni_dvp);
                error = EXDEV;
                goto out;
        }

        error = VOP_LINK(nd.ni_dvp, vp, &nd.ni_cnd);
out:
        vrele(vp);
        return (error);
}

/*
 * Make a symbolic link.
 */
int
sys_symlink(struct proc *p, void *v, register_t *retval)
{
        struct sys_symlink_args /* {
                syscallarg(const char *) path;
                syscallarg(const char *) link;
        } */ *uap = v;

        return (dosymlinkat(p, SCARG(uap, path), AT_FDCWD, SCARG(uap, link)));
}

int
sys_symlinkat(struct proc *p, void *v, register_t *retval)
{
        struct sys_symlinkat_args /* {
                syscallarg(const char *) path;
                syscallarg(int) fd;
                syscallarg(const char *) link;
        } */ *uap = v;

        return (dosymlinkat(p, SCARG(uap, path), SCARG(uap, fd),
            SCARG(uap, link)));
}

int
dosymlinkat(struct proc *p, const char *upath, int fd, const char *link)
{
        struct vattr vattr;
        char *path;
        int error;
        struct nameidata nd;

        path = pool_get(&namei_pool, PR_WAITOK);
        error = copyinstr(upath, path, MAXPATHLEN, NULL);
        if (error)
                goto out;
        NDINITAT(&nd, CREATE, LOCKPARENT, UIO_USERSPACE, fd, link, p);
        nd.ni_pledge = PLEDGE_CPATH;
        nd.ni_unveil = UNVEIL_CREATE;
        if ((error = namei(&nd)) != 0)
                goto out;
        if (nd.ni_vp) {
                VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
                if (nd.ni_dvp == nd.ni_vp)
                        vrele(nd.ni_dvp);
                else
                        vput(nd.ni_dvp);
                vrele(nd.ni_vp);
                error = EEXIST;
                goto out;
        }
        vattr_null(&vattr);
        vattr.va_mode = ACCESSPERMS &~ p->p_fd->fd_cmask;
        error = VOP_SYMLINK(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr, path);
out:
        pool_put(&namei_pool, path);
        return (error);
}

/*
 * Delete a name from the filesystem.
 */
int
sys_unlink(struct proc *p, void *v, register_t *retval)
{
        struct sys_unlink_args /* {
                syscallarg(const char *) path;
        } */ *uap = v;

        return (dounlinkat(p, AT_FDCWD, SCARG(uap, path), 0));
}

int
sys_unlinkat(struct proc *p, void *v, register_t *retval)
{
        struct sys_unlinkat_args /* {
                syscallarg(int) fd;
                syscallarg(const char *) path;
                syscallarg(int) flag;
        } */ *uap = v;

        return (dounlinkat(p, SCARG(uap, fd), SCARG(uap, path),
            SCARG(uap, flag)));
}

int
dounlinkat(struct proc *p, int fd, const char *path, int flag)
{
        struct vnode *vp;
        int error;
        struct nameidata nd;

        if (flag & ~AT_REMOVEDIR)
                return (EINVAL);

        NDINITAT(&nd, DELETE, LOCKPARENT | LOCKLEAF, UIO_USERSPACE,
            fd, path, p);
        nd.ni_pledge = PLEDGE_CPATH;
        nd.ni_unveil = UNVEIL_CREATE;
        if ((error = namei(&nd)) != 0)
                return (error);
        vp = nd.ni_vp;

        if (flag & AT_REMOVEDIR) {
                if (vp->v_type != VDIR) {
                        error = ENOTDIR;
                        goto out;
                }
                /*
                 * No rmdir "." please.
                 */
                if (nd.ni_dvp == vp) {
                        error = EINVAL;
                        goto out;
                }
                /*
                 * A mounted on directory cannot be deleted.
                 */
                if (vp->v_mountedhere != NULL) {
                        error = EBUSY;
                        goto out;
                }
        }

        /*
         * The root of a mounted filesystem cannot be deleted.
         */
        if (vp->v_flag & VROOT)
                error = EBUSY;
out:
        if (!error) {
                if (flag & AT_REMOVEDIR) {
                        error = VOP_RMDIR(nd.ni_dvp, nd.ni_vp, &nd.ni_cnd);
                } else {
                        (void)uvm_vnp_uncache(vp);
                        error = VOP_REMOVE(nd.ni_dvp, nd.ni_vp, &nd.ni_cnd);
                }
        } else {
                VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
                if (nd.ni_dvp == vp)
                        vrele(nd.ni_dvp);
                else
                        vput(nd.ni_dvp);
                vput(vp);
        }
        return (error);
}

/*
 * Reposition read/write file offset.
 */
int
sys_lseek(struct proc *p, void *v, register_t *retval)
{
        struct sys_lseek_args /* {
                syscallarg(int) fd;
                syscallarg(off_t) offset;
                syscallarg(int) whence;
        } */ *uap = v;
        struct filedesc *fdp = p->p_fd;
        struct file *fp;
        off_t offset;
        int error;

        if ((fp = fd_getfile(fdp, SCARG(uap, fd))) == NULL)
                return (EBADF);
        if (fp->f_ops->fo_seek == NULL) {
                error = ESPIPE;
                goto bad;
        }
        offset = SCARG(uap, offset);

        error = (*fp->f_ops->fo_seek)(fp, &offset, SCARG(uap, whence), p);
        if (error)
                goto bad;

        *(off_t *)retval = offset;
        mtx_enter(&fp->f_mtx);
        fp->f_seek++;
        mtx_leave(&fp->f_mtx);
        error = 0;
 bad:
        FRELE(fp, p);
        return (error);
}

/*
 * Check access permissions.
 */
int
sys_access(struct proc *p, void *v, register_t *retval)
{
        struct sys_access_args /* {
                syscallarg(const char *) path;
                syscallarg(int) amode;
        } */ *uap = v;

        return (dofaccessat(p, AT_FDCWD, SCARG(uap, path),
            SCARG(uap, amode), 0));
}

int
sys_faccessat(struct proc *p, void *v, register_t *retval)
{
        struct sys_faccessat_args /* {
                syscallarg(int) fd;
                syscallarg(const char *) path;
                syscallarg(int) amode;
                syscallarg(int) flag;
        } */ *uap = v;

        return (dofaccessat(p, SCARG(uap, fd), SCARG(uap, path),
            SCARG(uap, amode), SCARG(uap, flag)));
}

int
dofaccessat(struct proc *p, int fd, const char *path, int amode, int flag)
{
        struct vnode *vp;
        struct ucred *newcred, *oldcred;
        struct nameidata nd;
        int vflags = 0, error;

        if (amode & ~(R_OK | W_OK | X_OK))
                return (EINVAL);
        if (flag & ~AT_EACCESS)
                return (EINVAL);

        newcred = NULL;
        oldcred = p->p_ucred;

        /*
         * If access as real ids was requested and they really differ,
         * give the thread new creds with them reset
         */
        if ((flag & AT_EACCESS) == 0 &&
            (oldcred->cr_uid != oldcred->cr_ruid ||
            (oldcred->cr_gid != oldcred->cr_rgid))) {
                p->p_ucred = newcred = crdup(oldcred);
                newcred->cr_uid = newcred->cr_ruid;
                newcred->cr_gid = newcred->cr_rgid;
        }

        NDINITAT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_USERSPACE, fd, path, p);
        nd.ni_pledge = PLEDGE_RPATH;
        nd.ni_unveil = UNVEIL_READ;
        if (amode & R_OK)
                vflags |= VREAD;
        if (amode & W_OK) {
                vflags |= VWRITE;
                nd.ni_unveil |= UNVEIL_WRITE;
        }
        if (amode & X_OK)
                vflags |= VEXEC;
        if ((error = namei(&nd)) != 0)
                goto out;
        vp = nd.ni_vp;

        /* Flags == 0 means only check for existence. */
        if (amode) {
                error = VOP_ACCESS(vp, vflags, p->p_ucred, p);
                if (!error && (vflags & VWRITE))
                        error = vn_writechk(vp);
        }
        vput(vp);
out:
        if (newcred != NULL) {
                p->p_ucred = oldcred;
                crfree(newcred);
        }
        return (error);
}

/*
 * Get file status; this version follows links.
 */
int
sys_stat(struct proc *p, void *v, register_t *retval)
{
        struct sys_stat_args /* {
                syscallarg(const char *) path;
                syscallarg(struct stat *) ub;
        } */ *uap = v;

        return (dofstatat(p, AT_FDCWD, SCARG(uap, path), SCARG(uap, ub), 0));
}

int
sys_fstatat(struct proc *p, void *v, register_t *retval)
{
        struct sys_fstatat_args /* {
                syscallarg(int) fd;
                syscallarg(const char *) path;
                syscallarg(struct stat *) buf;
                syscallarg(int) flag;
        } */ *uap = v;

        return (dofstatat(p, SCARG(uap, fd), SCARG(uap, path),
            SCARG(uap, buf), SCARG(uap, flag)));
}

int
dofstatat(struct proc *p, int fd, const char *path, struct stat *buf, int flag)
{
        struct stat sb;
        int error, follow;
        struct nameidata nd;

        if (flag & ~AT_SYMLINK_NOFOLLOW)
                return (EINVAL);


        follow = (flag & AT_SYMLINK_NOFOLLOW) ? NOFOLLOW : FOLLOW;
        NDINITAT(&nd, LOOKUP, follow | LOCKLEAF, UIO_USERSPACE, fd, path, p);
        nd.ni_pledge = PLEDGE_RPATH;
        nd.ni_unveil = UNVEIL_READ;
        KERNEL_LOCK();
        if ((error = namei(&nd)) != 0) {
                KERNEL_UNLOCK();
                return (error);
        }
        error = vn_stat(nd.ni_vp, &sb, p);
        vput(nd.ni_vp);
        KERNEL_UNLOCK();
        if (error)
                return (error);
        /* Don't let non-root see generation numbers (for NFS security) */
        if (suser(p))
                sb.st_gen = 0;
        error = copyout(&sb, buf, sizeof(sb));
#ifdef KTRACE
        if (error == 0 && KTRPOINT(p, KTR_STRUCT))
                ktrstat(p, &sb);
#endif
        return (error);
}

/*
 * Get file status; this version does not follow links.
 */
int
sys_lstat(struct proc *p, void *v, register_t *retval)
{
        struct sys_lstat_args /* {
                syscallarg(const char *) path;
                syscallarg(struct stat *) ub;
        } */ *uap = v;

        return (dofstatat(p, AT_FDCWD, SCARG(uap, path), SCARG(uap, ub),
            AT_SYMLINK_NOFOLLOW));
}

/*
 * Get configurable pathname variables.
 */
int
sys_pathconf(struct proc *p, void *v, register_t *retval)
{
        struct sys_pathconf_args /* {
                syscallarg(const char *) path;
                syscallarg(int) name;
        } */ *uap = v;

        return dopathconfat(p, AT_FDCWD, SCARG(uap, path), SCARG(uap, name),
            0, retval);
}

int
sys_pathconfat(struct proc *p, void *v, register_t *retval)
{
        struct sys_pathconfat_args /* {
                syscallarg(int) fd;
                syscallarg(const char *) path;
                syscallarg(int) name;
                syscallarg(int) flag;
        } */ *uap = v;

        return dopathconfat(p, SCARG(uap, fd), SCARG(uap, path),
            SCARG(uap, name), SCARG(uap, flag), retval);
}

int
dopathconfat(struct proc *p, int fd, const char *path, int name, int flag,
    register_t *retval)
{
        int follow, error;
        struct nameidata nd;

        if (flag & ~AT_SYMLINK_NOFOLLOW)
                return EINVAL;

        follow = (flag & AT_SYMLINK_NOFOLLOW) ? NOFOLLOW : FOLLOW;
        NDINITAT(&nd, LOOKUP, follow | LOCKLEAF, UIO_USERSPACE, fd, path, p);
        nd.ni_pledge = PLEDGE_RPATH;
        nd.ni_unveil = UNVEIL_READ;
        if ((error = namei(&nd)) != 0)
                return (error);
        error = VOP_PATHCONF(nd.ni_vp, name, retval);
        vput(nd.ni_vp);
        return (error);
}

/*
 * Return target name of a symbolic link.
 */
int
sys_readlink(struct proc *p, void *v, register_t *retval)
{
        struct sys_readlink_args /* {
                syscallarg(const char *) path;
                syscallarg(char *) buf;
                syscallarg(size_t) count;
        } */ *uap = v;

        return (doreadlinkat(p, AT_FDCWD, SCARG(uap, path), SCARG(uap, buf),
            SCARG(uap, count), retval));
}

int
sys_readlinkat(struct proc *p, void *v, register_t *retval)
{
        struct sys_readlinkat_args /* {
                syscallarg(int) fd;
                syscallarg(const char *) path;
                syscallarg(char *) buf;
                syscallarg(size_t) count;
        } */ *uap = v;

        return (doreadlinkat(p, SCARG(uap, fd), SCARG(uap, path),
            SCARG(uap, buf), SCARG(uap, count), retval));
}

int
doreadlinkat(struct proc *p, int fd, const char *path, char *buf,
    size_t count, register_t *retval)
{
        struct vnode *vp;
        struct iovec aiov;
        struct uio auio;
        int error;
        struct nameidata nd;

        NDINITAT(&nd, LOOKUP, NOFOLLOW | LOCKLEAF, UIO_USERSPACE, fd, path, p);
        nd.ni_pledge = PLEDGE_RPATH;
        nd.ni_unveil = UNVEIL_READ;
        if ((error = namei(&nd)) != 0)
                return (error);
        vp = nd.ni_vp;
        if (vp->v_type != VLNK)
                error = EINVAL;
        else {
                aiov.iov_base = buf;
                aiov.iov_len = count;
                auio.uio_iov = &aiov;
                auio.uio_iovcnt = 1;
                auio.uio_offset = 0;
                auio.uio_rw = UIO_READ;
                auio.uio_segflg = UIO_USERSPACE;
                auio.uio_procp = p;
                auio.uio_resid = count;
                error = VOP_READLINK(vp, &auio, p->p_ucred);
                *retval = count - auio.uio_resid;
        }
        vput(vp);
        return (error);
}

/*
 * Change flags of a file given a path name.
 */
int
sys_chflags(struct proc *p, void *v, register_t *retval)
{
        struct sys_chflags_args /* {
                syscallarg(const char *) path;
                syscallarg(u_int) flags;
        } */ *uap = v;

        return (dochflagsat(p, AT_FDCWD, SCARG(uap, path),
            SCARG(uap, flags), 0));
}

int
sys_chflagsat(struct proc *p, void *v, register_t *retval)
{
        struct sys_chflagsat_args /* {
                syscallarg(int) fd;
                syscallarg(const char *) path;
                syscallarg(u_int) flags;
                syscallarg(int) atflags;
        } */ *uap = v;

        return (dochflagsat(p, SCARG(uap, fd), SCARG(uap, path),
            SCARG(uap, flags), SCARG(uap, atflags)));
}

int
dochflagsat(struct proc *p, int fd, const char *path, u_int flags, int atflags)
{
        struct nameidata nd;
        int error, follow;

        if (atflags & ~AT_SYMLINK_NOFOLLOW)
                return (EINVAL);

        follow = (atflags & AT_SYMLINK_NOFOLLOW) ? NOFOLLOW : FOLLOW;
        NDINITAT(&nd, LOOKUP, follow, UIO_USERSPACE, fd, path, p);
        nd.ni_pledge = PLEDGE_FATTR | PLEDGE_RPATH;
        nd.ni_unveil = UNVEIL_WRITE;
        if ((error = namei(&nd)) != 0)
                return (error);
        return (dovchflags(p, nd.ni_vp, flags));
}

/*
 * Change flags of a file given a file descriptor.
 */
int
sys_fchflags(struct proc *p, void *v, register_t *retval)
{
        struct sys_fchflags_args /* {
                syscallarg(int) fd;
                syscallarg(u_int) flags;
        } */ *uap = v;
        struct file *fp;
        struct vnode *vp;
        int error;

        if ((error = getvnode(p, SCARG(uap, fd), &fp)) != 0)
                return (error);
        vp = fp->f_data;
        if (p->p_fd->fd_ofileflags[SCARG(uap, fd)] & UF_PLEDGEOPEN) {
                vput(vp);
                return (EPERM);
        }
        vref(vp);
        FRELE(fp, p);
        return (dovchflags(p, vp, SCARG(uap, flags)));
}

int
dovchflags(struct proc *p, struct vnode *vp, u_int flags)
{
        struct vattr vattr;
        int error;

        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
        if (vp->v_mount && vp->v_mount->mnt_flag & MNT_RDONLY)
                error = EROFS;
        else if (flags == VNOVAL)
                error = EINVAL;
        else {
                if (suser(p)) {
                        if ((error = VOP_GETATTR(vp, &vattr, p->p_ucred, p))
                            != 0)
                                goto out;
                        if (vattr.va_type == VCHR || vattr.va_type == VBLK) {
                                error = EINVAL;
                                goto out;
                        }
                }
                vattr_null(&vattr);
                vattr.va_flags = flags;
                error = VOP_SETATTR(vp, &vattr, p->p_ucred, p);
        }
out:
        vput(vp);
        return (error);
}

/*
 * Change mode of a file given path name.
 */
int
sys_chmod(struct proc *p, void *v, register_t *retval)
{
        struct sys_chmod_args /* {
                syscallarg(const char *) path;
                syscallarg(mode_t) mode;
        } */ *uap = v;

        return (dofchmodat(p, AT_FDCWD, SCARG(uap, path), SCARG(uap, mode), 0));
}

int
sys_fchmodat(struct proc *p, void *v, register_t *retval)
{
        struct sys_fchmodat_args /* {
                syscallarg(int) fd;
                syscallarg(const char *) path;
                syscallarg(mode_t) mode;
                syscallarg(int) flag;
        } */ *uap = v;

        return (dofchmodat(p, SCARG(uap, fd), SCARG(uap, path),
            SCARG(uap, mode), SCARG(uap, flag)));
}

int
dofchmodat(struct proc *p, int fd, const char *path, mode_t mode, int flag)
{
        struct vnode *vp;
        struct vattr vattr;
        int error, follow;
        struct nameidata nd;

        if (mode & ~(S_IFMT | ALLPERMS))
                return (EINVAL);
        if ((p->p_p->ps_flags & PS_PLEDGE))
                mode &= ACCESSPERMS;
        if (flag & ~AT_SYMLINK_NOFOLLOW)
                return (EINVAL);

        follow = (flag & AT_SYMLINK_NOFOLLOW) ? NOFOLLOW : FOLLOW;
        NDINITAT(&nd, LOOKUP, follow, UIO_USERSPACE, fd, path, p);
        nd.ni_pledge = PLEDGE_FATTR | PLEDGE_RPATH;
        nd.ni_unveil = UNVEIL_WRITE;
        if ((error = namei(&nd)) != 0)
                return (error);
        vp = nd.ni_vp;
        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
        if (vp->v_mount->mnt_flag & MNT_RDONLY)
                error = EROFS;
        else {
                vattr_null(&vattr);
                vattr.va_mode = mode & ALLPERMS;
                error = VOP_SETATTR(vp, &vattr, p->p_ucred, p);
        }
        vput(vp);
        return (error);
}

/*
 * Change mode of a file given a file descriptor.
 */
int
sys_fchmod(struct proc *p, void *v, register_t *retval)
{
        struct sys_fchmod_args /* {
                syscallarg(int) fd;
                syscallarg(mode_t) mode;
        } */ *uap = v;
        struct vattr vattr;
        struct vnode *vp;
        struct file *fp;
        mode_t mode = SCARG(uap, mode);
        int error;

        if (mode & ~(S_IFMT | ALLPERMS))
                return (EINVAL);
        if ((p->p_p->ps_flags & PS_PLEDGE))
                mode &= ACCESSPERMS;

        if ((error = getvnode(p, SCARG(uap, fd), &fp)) != 0)
                return (error);
        vp = fp->f_data;
        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
        if (vp->v_mount && vp->v_mount->mnt_flag & MNT_RDONLY)
                error = EROFS;
        else if (p->p_fd->fd_ofileflags[SCARG(uap, fd)] & UF_PLEDGEOPEN)
                error = EPERM;
        else {
                vattr_null(&vattr);
                vattr.va_mode = mode & ALLPERMS;
                error = VOP_SETATTR(vp, &vattr, p->p_ucred, p);
        }
        VOP_UNLOCK(vp);
        FRELE(fp, p);
        return (error);
}

/*
 * Set ownership given a path name.
 */
int
sys_chown(struct proc *p, void *v, register_t *retval)
{
        struct sys_chown_args /* {
                syscallarg(const char *) path;
                syscallarg(uid_t) uid;
                syscallarg(gid_t) gid;
        } */ *uap = v;

        return (dofchownat(p, AT_FDCWD, SCARG(uap, path), SCARG(uap, uid),
            SCARG(uap, gid), 0));
}

int
sys_fchownat(struct proc *p, void *v, register_t *retval)
{
        struct sys_fchownat_args /* {
                syscallarg(int) fd;
                syscallarg(const char *) path;
                syscallarg(uid_t) uid;
                syscallarg(gid_t) gid;
                syscallarg(int) flag;
        } */ *uap = v;

        return (dofchownat(p, SCARG(uap, fd), SCARG(uap, path),
            SCARG(uap, uid), SCARG(uap, gid), SCARG(uap, flag)));
}

int
dofchownat(struct proc *p, int fd, const char *path, uid_t uid, gid_t gid,
    int flag)
{
        struct vnode *vp;
        struct vattr vattr;
        int error, follow;
        struct nameidata nd;
        mode_t mode;

        if (flag & ~AT_SYMLINK_NOFOLLOW)
                return (EINVAL);

        follow = (flag & AT_SYMLINK_NOFOLLOW) ? NOFOLLOW : FOLLOW;
        NDINITAT(&nd, LOOKUP, follow, UIO_USERSPACE, fd, path, p);
        nd.ni_pledge = PLEDGE_CHOWN | PLEDGE_RPATH;
        nd.ni_unveil = UNVEIL_WRITE;
        if ((error = namei(&nd)) != 0)
                return (error);
        vp = nd.ni_vp;
        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
        if (vp->v_mount->mnt_flag & MNT_RDONLY)
                error = EROFS;
        else {
                if ((error = pledge_chown(p, uid, gid)))
                        goto out;
                if ((uid != -1 || gid != -1) && !vnoperm(vp)) {
                        error = VOP_GETATTR(vp, &vattr, p->p_ucred, p);
                        if (error)
                                goto out;
                        mode = vattr.va_mode & ~(VSUID | VSGID);
                        if (mode == vattr.va_mode)
                                mode = VNOVAL;
                } else
                        mode = VNOVAL;
                vattr_null(&vattr);
                vattr.va_uid = uid;
                vattr.va_gid = gid;
                vattr.va_mode = mode;
                error = VOP_SETATTR(vp, &vattr, p->p_ucred, p);
        }
out:
        vput(vp);
        return (error);
}

/*
 * Set ownership given a path name, without following links.
 */
int
sys_lchown(struct proc *p, void *v, register_t *retval)
{
        struct sys_lchown_args /* {
                syscallarg(const char *) path;
                syscallarg(uid_t) uid;
                syscallarg(gid_t) gid;
        } */ *uap = v;
        struct vnode *vp;
        struct vattr vattr;
        int error;
        struct nameidata nd;
        mode_t mode;
        uid_t uid = SCARG(uap, uid);
        gid_t gid = SCARG(uap, gid);

        NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
        nd.ni_pledge = PLEDGE_CHOWN | PLEDGE_RPATH;
        nd.ni_unveil = UNVEIL_WRITE;
        if ((error = namei(&nd)) != 0)
                return (error);
        vp = nd.ni_vp;
        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
        if (vp->v_mount->mnt_flag & MNT_RDONLY)
                error = EROFS;
        else {
                if ((error = pledge_chown(p, uid, gid)))
                        goto out;
                if ((uid != -1 || gid != -1) && !vnoperm(vp)) {
                        error = VOP_GETATTR(vp, &vattr, p->p_ucred, p);
                        if (error)
                                goto out;
                        mode = vattr.va_mode & ~(VSUID | VSGID);
                        if (mode == vattr.va_mode)
                                mode = VNOVAL;
                } else
                        mode = VNOVAL;
                vattr_null(&vattr);
                vattr.va_uid = uid;
                vattr.va_gid = gid;
                vattr.va_mode = mode;
                error = VOP_SETATTR(vp, &vattr, p->p_ucred, p);
        }
out:
        vput(vp);
        return (error);
}

/*
 * Set ownership given a file descriptor.
 */
int
sys_fchown(struct proc *p, void *v, register_t *retval)
{
        struct sys_fchown_args /* {
                syscallarg(int) fd;
                syscallarg(uid_t) uid;
                syscallarg(gid_t) gid;
        } */ *uap = v;
        struct vnode *vp;
        struct vattr vattr;
        int error;
        struct file *fp;
        mode_t mode;
        uid_t uid = SCARG(uap, uid);
        gid_t gid = SCARG(uap, gid);

        if ((error = getvnode(p, SCARG(uap, fd), &fp)) != 0)
                return (error);
        vp = fp->f_data;
        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
        if (vp->v_mount && (vp->v_mount->mnt_flag & MNT_RDONLY))
                error = EROFS;
        else if (p->p_fd->fd_ofileflags[SCARG(uap, fd)] & UF_PLEDGEOPEN)
                error = EPERM;
        else {
                if ((error = pledge_chown(p, uid, gid)))
                        goto out;
                if ((uid != -1 || gid != -1) && !vnoperm(vp)) {
                        error = VOP_GETATTR(vp, &vattr, p->p_ucred, p);
                        if (error)
                                goto out;
                        mode = vattr.va_mode & ~(VSUID | VSGID);
                        if (mode == vattr.va_mode)
                                mode = VNOVAL;
                } else
                        mode = VNOVAL;
                vattr_null(&vattr);
                vattr.va_uid = uid;
                vattr.va_gid = gid;
                vattr.va_mode = mode;
                error = VOP_SETATTR(vp, &vattr, p->p_ucred, p);
        }
out:
        VOP_UNLOCK(vp);
        FRELE(fp, p);
        return (error);
}

/*
 * Set the access and modification times given a path name.
 */
int
sys_utimes(struct proc *p, void *v, register_t *retval)
{
        struct sys_utimes_args /* {
                syscallarg(const char *) path;
                syscallarg(const struct timeval *) tptr;
        } */ *uap = v;

        struct timespec ts[2];
        struct timeval tv[2];
        const struct timeval *tvp;
        int error;

        tvp = SCARG(uap, tptr);
        if (tvp != NULL) {
                error = copyin(tvp, tv, sizeof(tv));
                if (error)
                        return (error);
#ifdef KTRACE
                if (KTRPOINT(p, KTR_STRUCT))
                        ktrabstimeval(p, &tv);
#endif
                if (!timerisvalid(&tv[0]) || !timerisvalid(&tv[1]))
                        return (EINVAL);
                TIMEVAL_TO_TIMESPEC(&tv[0], &ts[0]);
                TIMEVAL_TO_TIMESPEC(&tv[1], &ts[1]);
        } else
                ts[0].tv_nsec = ts[1].tv_nsec = UTIME_NOW;

        return (doutimensat(p, AT_FDCWD, SCARG(uap, path), ts, 0));
}

int
sys_utimensat(struct proc *p, void *v, register_t *retval)
{
        struct sys_utimensat_args /* {
                syscallarg(int) fd;
                syscallarg(const char *) path;
                syscallarg(const struct timespec *) times;
                syscallarg(int) flag;
        } */ *uap = v;

        struct timespec ts[2];
        const struct timespec *tsp;
        int error, i;

        tsp = SCARG(uap, times);
        if (tsp != NULL) {
                error = copyin(tsp, ts, sizeof(ts));
                if (error)
                        return (error);
                for (i = 0; i < nitems(ts); i++) {
                        if (ts[i].tv_nsec == UTIME_NOW)
                                continue;
                        if (ts[i].tv_nsec == UTIME_OMIT)
                                continue;
#ifdef KTRACE
                        if (KTRPOINT(p, KTR_STRUCT))
                                ktrabstimespec(p, &ts[i]);
#endif
                        if (!timespecisvalid(&ts[i]))
                                return (EINVAL);
                }
        } else
                ts[0].tv_nsec = ts[1].tv_nsec = UTIME_NOW;

        return (doutimensat(p, SCARG(uap, fd), SCARG(uap, path), ts,
            SCARG(uap, flag)));
}

int
doutimensat(struct proc *p, int fd, const char *path,
    struct timespec ts[2], int flag)
{
        struct vnode *vp;
        int error, follow;
        struct nameidata nd;

        if (flag & ~AT_SYMLINK_NOFOLLOW)
                return (EINVAL);

        follow = (flag & AT_SYMLINK_NOFOLLOW) ? NOFOLLOW : FOLLOW;
        NDINITAT(&nd, LOOKUP, follow, UIO_USERSPACE, fd, path, p);
        nd.ni_pledge = PLEDGE_FATTR | PLEDGE_RPATH;
        nd.ni_unveil = UNVEIL_WRITE;
        if ((error = namei(&nd)) != 0)
                return (error);
        vp = nd.ni_vp;

        return (dovutimens(p, vp, ts));
}

int
dovutimens(struct proc *p, struct vnode *vp, struct timespec ts[2])
{
        struct vattr vattr;
        struct timespec now;
        int error;

#ifdef KTRACE
        /* if they're both UTIME_NOW, then don't report either */
        if ((ts[0].tv_nsec != UTIME_NOW || ts[1].tv_nsec != UTIME_NOW) &&
            KTRPOINT(p, KTR_STRUCT)) {
                ktrabstimespec(p, &ts[0]);
                ktrabstimespec(p, &ts[1]);
        }
#endif

        vattr_null(&vattr);

        /*  make sure ctime is updated even if neither mtime nor atime is */
        vattr.va_vaflags = VA_UTIMES_CHANGE;

        if (ts[0].tv_nsec == UTIME_NOW || ts[1].tv_nsec == UTIME_NOW) {
                if (ts[0].tv_nsec == UTIME_NOW && ts[1].tv_nsec == UTIME_NOW)
                        vattr.va_vaflags |= VA_UTIMES_NULL;

                getnanotime(&now);
                if (ts[0].tv_nsec == UTIME_NOW)
                        ts[0] = now;
                if (ts[1].tv_nsec == UTIME_NOW)
                        ts[1] = now;
        }

        if (ts[0].tv_nsec != UTIME_OMIT)
                vattr.va_atime = ts[0];
        if (ts[1].tv_nsec != UTIME_OMIT)
                vattr.va_mtime = ts[1];

        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
        if (vp->v_mount->mnt_flag & MNT_RDONLY)
                error = EROFS;
        else
                error = VOP_SETATTR(vp, &vattr, p->p_ucred, p);
        vput(vp);
        return (error);
}

/*
 * Set the access and modification times given a file descriptor.
 */
int
sys_futimes(struct proc *p, void *v, register_t *retval)
{
        struct sys_futimes_args /* {
                syscallarg(int) fd;
                syscallarg(const struct timeval *) tptr;
        } */ *uap = v;
        struct timeval tv[2];
        struct timespec ts[2];
        const struct timeval *tvp;
        int error;

        tvp = SCARG(uap, tptr);
        if (tvp != NULL) {
                error = copyin(tvp, tv, sizeof(tv));
                if (error)
                        return (error);
#ifdef KTRACE
                if (KTRPOINT(p, KTR_STRUCT)) {
                        ktrabstimeval(p, &tv[0]);
                        ktrabstimeval(p, &tv[1]);
                }
#endif
                if (!timerisvalid(&tv[0]) || !timerisvalid(&tv[1]))
                        return (EINVAL);
                TIMEVAL_TO_TIMESPEC(&tv[0], &ts[0]);
                TIMEVAL_TO_TIMESPEC(&tv[1], &ts[1]);
        } else
                ts[0].tv_nsec = ts[1].tv_nsec = UTIME_NOW;

        return (dofutimens(p, SCARG(uap, fd), ts));
}

int
sys_futimens(struct proc *p, void *v, register_t *retval)
{
        struct sys_futimens_args /* {
                syscallarg(int) fd;
                syscallarg(const struct timespec *) times;
        } */ *uap = v;
        struct timespec ts[2];
        const struct timespec *tsp;
        int error, i;

        tsp = SCARG(uap, times);
        if (tsp != NULL) {
                error = copyin(tsp, ts, sizeof(ts));
                if (error)
                        return (error);
                for (i = 0; i < nitems(ts); i++) {
                        if (ts[i].tv_nsec == UTIME_NOW)
                                continue;
                        if (ts[i].tv_nsec == UTIME_OMIT)
                                continue;
#ifdef KTRACE
                        if (KTRPOINT(p, KTR_STRUCT))
                                ktrabstimespec(p, &ts[i]);
#endif
                        if (!timespecisvalid(&ts[i]))
                                return (EINVAL);
                }
        } else
                ts[0].tv_nsec = ts[1].tv_nsec = UTIME_NOW;

        return (dofutimens(p, SCARG(uap, fd), ts));
}

int
dofutimens(struct proc *p, int fd, struct timespec ts[2])
{
        struct file *fp;
        struct vnode *vp;
        int error;

        if ((error = getvnode(p, fd, &fp)) != 0)
                return (error);
        vp = fp->f_data;
        vref(vp);
        FRELE(fp, p);

        return (dovutimens(p, vp, ts));
}

/*
 * Truncate a file given a vnode.
 */
int
dotruncate(struct proc *p, struct vnode *vp, off_t len)
{
        struct vattr vattr;
        int error;

        if (len < 0)
                return EINVAL;
        if (vp->v_type == VDIR)
                return EISDIR;
        if ((error = vn_writechk(vp)) != 0)
                return error;
        if (vp->v_type == VREG && len > lim_cur_proc(p, RLIMIT_FSIZE)) {
                if ((error = VOP_GETATTR(vp, &vattr, p->p_ucred, p)) != 0)
                        return error;
                if (len > vattr.va_size) {
                        /* if extending over the limit, send signal and fail */
                        psignal(p, SIGXFSZ);
                        return EFBIG;
                }
        }
        vattr_null(&vattr);
        vattr.va_size = len;
        return VOP_SETATTR(vp, &vattr, p->p_ucred, p);
}

/*
 * Truncate a file given its path name.
 */
int
sys_truncate(struct proc *p, void *v, register_t *retval)
{
        struct sys_truncate_args /* {
                syscallarg(const char *) path;
                syscallarg(off_t) length;
        } */ *uap = v;
        struct vnode *vp;
        int error;
        struct nameidata nd;

        NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
        nd.ni_pledge = PLEDGE_FATTR | PLEDGE_RPATH;
        nd.ni_unveil = UNVEIL_WRITE;
        if ((error = namei(&nd)) != 0)
                return (error);
        vp = nd.ni_vp;
        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
        if ((error = VOP_ACCESS(vp, VWRITE, p->p_ucred, p)) == 0)
                error = dotruncate(p, vp, SCARG(uap, length));
        vput(vp);
        return (error);
}

/*
 * Truncate a file given a file descriptor.
 */
int
sys_ftruncate(struct proc *p, void *v, register_t *retval)
{
        struct sys_ftruncate_args /* {
                syscallarg(int) fd;
                syscallarg(off_t) length;
        } */ *uap = v;
        struct vnode *vp;
        struct file *fp;
        int error;

        if ((error = getvnode(p, SCARG(uap, fd), &fp)) != 0)
                return (error);
        if ((fp->f_flag & FWRITE) == 0) {
                error = EINVAL;
                goto bad;
        } else if (p->p_fd->fd_ofileflags[SCARG(uap, fd)] & UF_PLEDGEOPEN) {
                error = EPERM;
                goto bad;
        }
        vp = fp->f_data;
        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
        error = dotruncate(p, vp, SCARG(uap, length));
        VOP_UNLOCK(vp);
bad:
        FRELE(fp, p);
        return (error);
}

/*
 * Sync an open file.
 */
int
sys_fsync(struct proc *p, void *v, register_t *retval)
{
        struct sys_fsync_args /* {
                syscallarg(int) fd;
        } */ *uap = v;
        struct vnode *vp;
        struct file *fp;
        int error;

        if ((error = getvnode(p, SCARG(uap, fd), &fp)) != 0)
                return (error);
        vp = fp->f_data;
        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
        error = VOP_FSYNC(vp, fp->f_cred, MNT_WAIT, p);

        VOP_UNLOCK(vp);
        FRELE(fp, p);
        return (error);
}

/*
 * Rename files.  Source and destination must either both be directories,
 * or both not be directories.  If target is a directory, it must be empty.
 */
int
sys_rename(struct proc *p, void *v, register_t *retval)
{
        struct sys_rename_args /* {
                syscallarg(const char *) from;
                syscallarg(const char *) to;
        } */ *uap = v;

        return (dorenameat(p, AT_FDCWD, SCARG(uap, from), AT_FDCWD,
            SCARG(uap, to)));
}

int
sys_renameat(struct proc *p, void *v, register_t *retval)
{
        struct sys_renameat_args /* {
                syscallarg(int) fromfd;
                syscallarg(const char *) from;
                syscallarg(int) tofd;
                syscallarg(const char *) to;
        } */ *uap = v;

        return (dorenameat(p, SCARG(uap, fromfd), SCARG(uap, from),
            SCARG(uap, tofd), SCARG(uap, to)));
}

int
dorenameat(struct proc *p, int fromfd, const char *from, int tofd,
    const char *to)
{
        struct vnode *tvp, *fvp, *tdvp;
        struct nameidata fromnd, tond;
        int error;
        int flags;

        NDINITAT(&fromnd, DELETE, WANTPARENT | SAVESTART, UIO_USERSPACE,
            fromfd, from, p);
        fromnd.ni_pledge = PLEDGE_RPATH | PLEDGE_CPATH;
        fromnd.ni_unveil = UNVEIL_READ | UNVEIL_CREATE;
        if ((error = namei(&fromnd)) != 0)
                return (error);
        fvp = fromnd.ni_vp;

        flags = LOCKPARENT | LOCKLEAF | NOCACHE | SAVESTART;
        /*
         * rename("foo/", "bar/");  is  OK
         */
        if (fvp->v_type == VDIR)
                flags |= STRIPSLASHES;

        NDINITAT(&tond, RENAME, flags, UIO_USERSPACE, tofd, to, p);
        tond.ni_pledge = PLEDGE_CPATH;
        tond.ni_unveil = UNVEIL_CREATE;
        if ((error = namei(&tond)) != 0) {
                VOP_ABORTOP(fromnd.ni_dvp, &fromnd.ni_cnd);
                vrele(fromnd.ni_dvp);
                vrele(fvp);
                goto out1;
        }
        tdvp = tond.ni_dvp;
        tvp = tond.ni_vp;
        if (tvp != NULL) {
                if (fvp->v_type == VDIR && tvp->v_type != VDIR) {
                        error = ENOTDIR;
                        goto out;
                } else if (fvp->v_type != VDIR && tvp->v_type == VDIR) {
                        error = EISDIR;
                        goto out;
                }
        }
        if (fvp == tdvp)
                error = EINVAL;
        /*
         * If source is the same as the destination (that is the
         * same inode number)
         */
        if (fvp == tvp)
                error = -1;
out:
        if (!error) {
                if (tvp) {
                        (void)uvm_vnp_uncache(tvp);
                }
                error = VOP_RENAME(fromnd.ni_dvp, fromnd.ni_vp, &fromnd.ni_cnd,
                                   tond.ni_dvp, tond.ni_vp, &tond.ni_cnd);
        } else {
                VOP_ABORTOP(tond.ni_dvp, &tond.ni_cnd);
                if (tdvp == tvp)
                        vrele(tdvp);
                else
                        vput(tdvp);
                if (tvp)
                        vput(tvp);
                VOP_ABORTOP(fromnd.ni_dvp, &fromnd.ni_cnd);
                vrele(fromnd.ni_dvp);
                vrele(fvp);
        }
        vrele(tond.ni_startdir);
        pool_put(&namei_pool, tond.ni_cnd.cn_pnbuf);
out1:
        if (fromnd.ni_startdir)
                vrele(fromnd.ni_startdir);
        pool_put(&namei_pool, fromnd.ni_cnd.cn_pnbuf);
        if (error == -1)
                return (0);
        return (error);
}

/*
 * Make a directory file.
 */
int
sys_mkdir(struct proc *p, void *v, register_t *retval)
{
        struct sys_mkdir_args /* {
                syscallarg(const char *) path;
                syscallarg(mode_t) mode;
        } */ *uap = v;

        return (domkdirat(p, AT_FDCWD, SCARG(uap, path), SCARG(uap, mode)));
}

int
sys_mkdirat(struct proc *p, void *v, register_t *retval)
{
        struct sys_mkdirat_args /* {
                syscallarg(int) fd;
                syscallarg(const char *) path;
                syscallarg(mode_t) mode;
        } */ *uap = v;

        return (domkdirat(p, SCARG(uap, fd), SCARG(uap, path),
            SCARG(uap, mode)));
}

int
domkdirat(struct proc *p, int fd, const char *path, mode_t mode)
{
        struct vnode *vp;
        struct vattr vattr;
        int error;
        struct nameidata nd;

        NDINITAT(&nd, CREATE, LOCKPARENT | STRIPSLASHES, UIO_USERSPACE,
            fd, path, p);
        nd.ni_pledge = PLEDGE_CPATH;
        nd.ni_unveil = UNVEIL_CREATE;
        if ((error = namei(&nd)) != 0)
                return (error);
        vp = nd.ni_vp;
        if (vp != NULL) {
                VOP_ABORTOP(nd.ni_dvp, &nd.ni_cnd);
                if (nd.ni_dvp == vp)
                        vrele(nd.ni_dvp);
                else
                        vput(nd.ni_dvp);
                vrele(vp);
                return (EEXIST);
        }
        vattr_null(&vattr);
        vattr.va_type = VDIR;
        vattr.va_mode = (mode & ACCESSPERMS) &~ p->p_fd->fd_cmask;
        error = VOP_MKDIR(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr);
        if (!error)
                vput(nd.ni_vp);
        return (error);
}

/*
 * Remove a directory file.
 */
int
sys_rmdir(struct proc *p, void *v, register_t *retval)
{
        struct sys_rmdir_args /* {
                syscallarg(const char *) path;
        } */ *uap = v;

        return (dounlinkat(p, AT_FDCWD, SCARG(uap, path), AT_REMOVEDIR));
}

/*
 * Read a block of directory entries in a file system independent format.
 */
int
sys_getdents(struct proc *p, void *v, register_t *retval)
{
        struct sys_getdents_args /* {
                syscallarg(int) fd;
                syscallarg(void *) buf;
                syscallarg(size_t) buflen;
        } */ *uap = v;
        struct vnode *vp;
        struct file *fp;
        struct uio auio;
        struct iovec aiov;
        size_t buflen;
        int error, eofflag;

        buflen = SCARG(uap, buflen);

        if (buflen > INT_MAX)
                return (EINVAL);
        if ((error = getvnode(p, SCARG(uap, fd), &fp)) != 0)
                return (error);
        if ((fp->f_flag & FREAD) == 0) {
                error = EBADF;
                goto bad;
        }
        vp = fp->f_data;
        if (vp->v_type != VDIR) {
                error = EINVAL;
                goto bad;
        }

        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);

        if (fp->f_offset < 0) {
                VOP_UNLOCK(vp);
                error = EINVAL;
                goto bad;
        }

        aiov.iov_base = SCARG(uap, buf);
        aiov.iov_len = buflen;
        auio.uio_iov = &aiov;
        auio.uio_iovcnt = 1;
        auio.uio_rw = UIO_READ;
        auio.uio_segflg = UIO_USERSPACE;
        auio.uio_procp = p;
        auio.uio_resid = buflen;
        auio.uio_offset = fp->f_offset;
        error = VOP_READDIR(vp, &auio, fp->f_cred, &eofflag);
        mtx_enter(&fp->f_mtx);
        fp->f_offset = auio.uio_offset;
        mtx_leave(&fp->f_mtx);
        VOP_UNLOCK(vp);
        if (error)
                goto bad;
        *retval = buflen - auio.uio_resid;
bad:
        FRELE(fp, p);
        return (error);
}

/*
 * Set the mode mask for creation of filesystem nodes.
 */
int
sys_umask(struct proc *p, void *v, register_t *retval)
{
        struct sys_umask_args /* {
                syscallarg(mode_t) newmask;
        } */ *uap = v;
        struct filedesc *fdp = p->p_fd;

        fdplock(fdp);
        *retval = fdp->fd_cmask;
        fdp->fd_cmask = SCARG(uap, newmask) & ACCESSPERMS;
        fdpunlock(fdp);
        return (0);
}

/*
 * Void all references to file by ripping underlying filesystem
 * away from vnode.
 */
int
sys_revoke(struct proc *p, void *v, register_t *retval)
{
        struct sys_revoke_args /* {
                syscallarg(const char *) path;
        } */ *uap = v;
        struct vnode *vp;
        struct vattr vattr;
        int error;
        struct nameidata nd;

        NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
        nd.ni_pledge = PLEDGE_RPATH | PLEDGE_TTY;
        nd.ni_unveil = UNVEIL_READ;
        if ((error = namei(&nd)) != 0)
                return (error);
        vp = nd.ni_vp;
        if (vp->v_type != VCHR || (u_int)major(vp->v_rdev) >= nchrdev ||
            cdevsw[major(vp->v_rdev)].d_type != D_TTY) {
                error = ENOTTY;
                goto out;
        }
        if ((error = VOP_GETATTR(vp, &vattr, p->p_ucred, p)) != 0)
                goto out;
        if (p->p_ucred->cr_uid != vattr.va_uid &&
            (error = suser(p)))
                goto out;
        if (vp->v_usecount > 1 || (vp->v_flag & (VALIASED)))
                VOP_REVOKE(vp, REVOKEALL);
out:
        vrele(vp);
        return (error);
}

/*
 * Convert a user file descriptor to a kernel file entry.
 *
 * On return *fpp is FREF:ed.
 */
int
getvnode(struct proc *p, int fd, struct file **fpp)
{
        struct file *fp;
        struct vnode *vp;

        if ((fp = fd_getfile(p->p_fd, fd)) == NULL)
                return (EBADF);

        if (fp->f_type != DTYPE_VNODE) {
                FRELE(fp, p);
                return (EINVAL);
        }

        vp = fp->f_data;
        if (vp->v_type == VBAD) {
                FRELE(fp, p);
                return (EBADF);
        }

        *fpp = fp;

        return (0);
}

/*
 * Positional read system call.
 */
int
sys_pread(struct proc *p, void *v, register_t *retval)
{
        struct sys_pread_args /* {
                syscallarg(int) fd;
                syscallarg(void *) buf;
                syscallarg(size_t) nbyte;
                syscallarg(off_t) offset;
        } */ *uap = v;
        struct iovec iov;
        struct uio auio;

        iov.iov_base = SCARG(uap, buf);
        iov.iov_len = SCARG(uap, nbyte);
        if (iov.iov_len > SSIZE_MAX)
                return (EINVAL);

        auio.uio_iov = &iov;
        auio.uio_iovcnt = 1;
        auio.uio_resid = iov.iov_len;
        auio.uio_offset = SCARG(uap, offset);

        return (dofilereadv(p, SCARG(uap, fd), &auio, FO_POSITION, retval));
}

/*
 * Positional scatter read system call.
 */
int
sys_preadv(struct proc *p, void *v, register_t *retval)
{
        struct sys_preadv_args /* {
                syscallarg(int) fd;
                syscallarg(const struct iovec *) iovp;
                syscallarg(int) iovcnt;
                syscallarg(off_t) offset;
        } */ *uap = v;
        struct iovec aiov[UIO_SMALLIOV], *iov = NULL;
        int error, iovcnt = SCARG(uap, iovcnt);
        struct uio auio;
        size_t resid;

        error = iovec_copyin(SCARG(uap, iovp), &iov, aiov, iovcnt, &resid);
        if (error)
                goto done;

        auio.uio_iov = iov;
        auio.uio_iovcnt = iovcnt;
        auio.uio_resid = resid;
        auio.uio_offset = SCARG(uap, offset);

        error = dofilereadv(p, SCARG(uap, fd), &auio, FO_POSITION, retval);
 done:
        iovec_free(iov, iovcnt);
        return (error);
}

/*
 * Positional write system call.
 */
int
sys_pwrite(struct proc *p, void *v, register_t *retval)
{
        struct sys_pwrite_args /* {
                syscallarg(int) fd;
                syscallarg(const void *) buf;
                syscallarg(size_t) nbyte;
                syscallarg(off_t) offset;
        } */ *uap = v;
        struct iovec iov;
        struct uio auio;

        iov.iov_base = (void *)SCARG(uap, buf);
        iov.iov_len = SCARG(uap, nbyte);
        if (iov.iov_len > SSIZE_MAX)
                return (EINVAL);

        auio.uio_iov = &iov;
        auio.uio_iovcnt = 1;
        auio.uio_resid = iov.iov_len;
        auio.uio_offset = SCARG(uap, offset);

        return (dofilewritev(p, SCARG(uap, fd), &auio, FO_POSITION, retval));
}

/*
 * Positional gather write system call.
 */
int
sys_pwritev(struct proc *p, void *v, register_t *retval)
{
        struct sys_pwritev_args /* {
                syscallarg(int) fd;
                syscallarg(const struct iovec *) iovp;
                syscallarg(int) iovcnt;
                syscallarg(off_t) offset;
        } */ *uap = v;
        struct iovec aiov[UIO_SMALLIOV], *iov = NULL;
        int error, iovcnt = SCARG(uap, iovcnt);
        struct uio auio;
        size_t resid;

        error = iovec_copyin(SCARG(uap, iovp), &iov, aiov, iovcnt, &resid);
        if (error)
                goto done;

        auio.uio_iov = iov;
        auio.uio_iovcnt = iovcnt;
        auio.uio_resid = resid;
        auio.uio_offset = SCARG(uap, offset);

        error = dofilewritev(p, SCARG(uap, fd), &auio, FO_POSITION, retval);
 done:
        iovec_free(iov, iovcnt);
        return (error);
}