[unix-history] / usr / src / sys / kern / vfs_syscalls.c

/*
* Copyright (c) 1989 The Regents of the University of California.
* All rights reserved.
*
* %sccs.include.redist.c%
*
*      @(#)vfs_syscalls.c      7.66 (Berkeley) %G%
*/

#include "param.h"
#include "systm.h"
#include "namei.h"
#include "filedesc.h"
#include "kernel.h"
#include "file.h"
#include "stat.h"
#include "vnode.h"
#include "mount.h"
#include "proc.h"
#include "uio.h"
#include "malloc.h"

/*
* Virtual File System System Calls
*/

/*
* mount system call
*/
/* ARGSUSED */
mount(p, uap, retval)
       struct proc *p;
       register struct args {
               int     type;
               char    *dir;
               int     flags;
               caddr_t data;
       } *uap;
       int *retval;
{
       register struct nameidata *ndp;
       register struct vnode *vp;
       register struct mount *mp;
       int error, flag;
       struct nameidata nd;

       /*
        * Must be super user
        */
       if (error = suser(p->p_ucred, &p->p_acflag))
               return (error);
       /*
        * Get vnode to be covered
        */
       ndp = &nd;
       ndp->ni_nameiop = LOOKUP | FOLLOW | LOCKLEAF;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->dir;
       if (error = namei(ndp, p))
               return (error);
       vp = ndp->ni_vp;
       if (uap->flags & MNT_UPDATE) {
               if ((vp->v_flag & VROOT) == 0) {
                       vput(vp);
                       return (EINVAL);
               }
               mp = vp->v_mount;
               /*
                * We allow going from read-only to read-write,
                * but not from read-write to read-only.
                */
               if ((mp->mnt_flag & MNT_RDONLY) == 0 &&
                   (uap->flags & MNT_RDONLY) != 0) {
                       vput(vp);
                       return (EOPNOTSUPP);    /* Needs translation */
               }
               flag = mp->mnt_flag;
               mp->mnt_flag |= MNT_UPDATE;
               VOP_UNLOCK(vp);
               goto update;
       }
       vinvalbuf(vp, 1);
       if (vp->v_usecount != 1) {
               vput(vp);
               return (EBUSY);
       }
       if (vp->v_type != VDIR) {
               vput(vp);
               return (ENOTDIR);
       }
       if ((unsigned long)uap->type > MOUNT_MAXTYPE ||
           vfssw[uap->type] == (struct vfsops *)0) {
               vput(vp);
               return (ENODEV);
       }

       /*
        * Allocate and initialize the file system.
        */
       mp = (struct mount *)malloc((u_long)sizeof(struct mount),
               M_MOUNT, M_WAITOK);
       mp->mnt_op = vfssw[uap->type];
       mp->mnt_flag = 0;
       mp->mnt_exroot = 0;
       mp->mnt_mounth = NULLVP;
       if (error = vfs_lock(mp)) {
               free((caddr_t)mp, M_MOUNT);
               vput(vp);
               return (error);
       }
       if (vp->v_mountedhere != (struct mount *)0) {
               vfs_unlock(mp);
               free((caddr_t)mp, M_MOUNT);
               vput(vp);
               return (EBUSY);
       }
       vp->v_mountedhere = mp;
       mp->mnt_vnodecovered = vp;
update:
       /*
        * Set the mount level flags.
        */
       if (uap->flags & MNT_RDONLY)
               mp->mnt_flag |= MNT_RDONLY;
       else
               mp->mnt_flag &= ~MNT_RDONLY;
       if (uap->flags & MNT_NOSUID)
               mp->mnt_flag |= MNT_NOSUID;
       else
               mp->mnt_flag &= ~MNT_NOSUID;
       if (uap->flags & MNT_NOEXEC)
               mp->mnt_flag |= MNT_NOEXEC;
       else
               mp->mnt_flag &= ~MNT_NOEXEC;
       if (uap->flags & MNT_NODEV)
               mp->mnt_flag |= MNT_NODEV;
       else
               mp->mnt_flag &= ~MNT_NODEV;
       if (uap->flags & MNT_SYNCHRONOUS)
               mp->mnt_flag |= MNT_SYNCHRONOUS;
       else
               mp->mnt_flag &= ~MNT_SYNCHRONOUS;
       /*
        * Mount the filesystem.
        */
       error = VFS_MOUNT(mp, uap->dir, uap->data, ndp);
       if (mp->mnt_flag & MNT_UPDATE) {
               mp->mnt_flag &= ~MNT_UPDATE;
               vrele(vp);
               if (error)
                       mp->mnt_flag = flag;
               return (error);
       }
       /*
        * Put the new filesystem on the mount list after root.
        */
       mp->mnt_next = rootfs->mnt_next;
       mp->mnt_prev = rootfs;
       rootfs->mnt_next = mp;
       mp->mnt_next->mnt_prev = mp;
       cache_purge(vp);
       if (!error) {
               VOP_UNLOCK(vp);
               vfs_unlock(mp);
               error = VFS_START(mp, 0);
       } else {
               vfs_remove(mp);
               free((caddr_t)mp, M_MOUNT);
               vput(vp);
       }
       return (error);
}

/*
* Unmount system call.
*
* Note: unmount takes a path to the vnode mounted on as argument,
* not special file (as before).
*/
/* ARGSUSED */
unmount(p, uap, retval)
       struct proc *p;
       register struct args {
               char    *pathp;
               int     flags;
       } *uap;
       int *retval;
{
       register struct vnode *vp;
       register struct nameidata *ndp;
       struct mount *mp;
       int error;
       struct nameidata nd;

       /*
        * Must be super user
        */
       if (error = suser(p->p_ucred, &p->p_acflag))
               return (error);

       ndp = &nd;
       ndp->ni_nameiop = LOOKUP | LOCKLEAF | FOLLOW;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->pathp;
       if (error = namei(ndp, p))
               return (error);
       vp = ndp->ni_vp;
       /*
        * Must be the root of the filesystem
        */
       if ((vp->v_flag & VROOT) == 0) {
               vput(vp);
               return (EINVAL);
       }
       mp = vp->v_mount;
       vput(vp);
       return (dounmount(mp, uap->flags));
}

/*
* Do an unmount.
*/
dounmount(mp, flags)
       register struct mount *mp;
       int flags;
{
       struct vnode *coveredvp;
       int error;

       coveredvp = mp->mnt_vnodecovered;
       if (vfs_busy(mp))
               return (EBUSY);
       mp->mnt_flag |= MNT_UNMOUNT;
       if (error = vfs_lock(mp))
               return (error);

#ifdef NVM
       vnode_pager_umount(mp); /* release cached vnodes */
#else
       xumount(mp);            /* remove unused sticky files from text table */
#endif
       cache_purgevfs(mp);     /* remove cache entries for this file sys */
       if ((error = VFS_SYNC(mp, MNT_WAIT)) == 0 || (flags & MNT_FORCE))
               error = VFS_UNMOUNT(mp, flags);
       mp->mnt_flag &= ~MNT_UNMOUNT;
       vfs_unbusy(mp);
       if (error) {
               vfs_unlock(mp);
       } else {
               vrele(coveredvp);
               vfs_remove(mp);
               free((caddr_t)mp, M_MOUNT);
       }
       return (error);
}

/*
* Sync system call.
* Sync each mounted filesystem.
*/
/* ARGSUSED */
sync(p, uap, retval)
       struct proc *p;
       void *uap;
       int *retval;
{
       register struct mount *mp;
       struct mount *omp;

       mp = rootfs;
       do {
               /*
                * The lock check below is to avoid races with mount
                * and unmount.
                */
               if ((mp->mnt_flag & (MNT_MLOCK|MNT_RDONLY|MNT_MPBUSY)) == 0 &&
                   !vfs_busy(mp)) {
                       VFS_SYNC(mp, MNT_NOWAIT);
                       omp = mp;
                       mp = mp->mnt_next;
                       vfs_unbusy(omp);
               } else
                       mp = mp->mnt_next;
       } while (mp != rootfs);
       return (0);
}

/*
* operate on filesystem quotas
*/
/* ARGSUSED */
quotactl(p, uap, retval)
       struct proc *p;
       register struct args {
               char *path;
               int cmd;
               int uid;
               caddr_t arg;
       } *uap;
       int *retval;
{
       register struct mount *mp;
       register struct nameidata *ndp;
       int error;
       struct nameidata nd;

       ndp = &nd;
       ndp->ni_nameiop = LOOKUP | FOLLOW;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->path;
       if (error = namei(ndp, p))
               return (error);
       mp = ndp->ni_vp->v_mount;
       vrele(ndp->ni_vp);
       return (VFS_QUOTACTL(mp, uap->cmd, uap->uid, uap->arg));
}

/*
* get filesystem statistics
*/
/* ARGSUSED */
statfs(p, uap, retval)
       struct proc *p;
       register struct args {
               char *path;
               struct statfs *buf;
       } *uap;
       int *retval;
{
       register struct mount *mp;
       register struct nameidata *ndp;
       register struct statfs *sp;
       int error;
       struct nameidata nd;

       ndp = &nd;
       ndp->ni_nameiop = LOOKUP | FOLLOW;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->path;
       if (error = namei(ndp, p))
               return (error);
       mp = ndp->ni_vp->v_mount;
       sp = &mp->mnt_stat;
       vrele(ndp->ni_vp);
       if (error = VFS_STATFS(mp, sp))
               return (error);
       sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
       return (copyout((caddr_t)sp, (caddr_t)uap->buf, sizeof(*sp)));
}

/*
* get filesystem statistics
*/
/* ARGSUSED */
fstatfs(p, uap, retval)
       struct proc *p;
       register struct args {
               int fd;
               struct statfs *buf;
       } *uap;
       int *retval;
{
       struct file *fp;
       struct mount *mp;
       register struct statfs *sp;
       int error;

       if (error = getvnode(p->p_fd, uap->fd, &fp))
               return (error);
       mp = ((struct vnode *)fp->f_data)->v_mount;
       sp = &mp->mnt_stat;
       if (error = VFS_STATFS(mp, sp))
               return (error);
       sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
       return (copyout((caddr_t)sp, (caddr_t)uap->buf, sizeof(*sp)));
}

/*
* get statistics on all filesystems
*/
getfsstat(p, uap, retval)
       struct proc *p;
       register struct args {
               struct statfs *buf;
               long bufsize;
               int flags;
       } *uap;
       int *retval;
{
       register struct mount *mp;
       register struct statfs *sp;
       caddr_t sfsp;
       long count, maxcount, error;

       maxcount = uap->bufsize / sizeof(struct statfs);
       sfsp = (caddr_t)uap->buf;
       mp = rootfs;
       count = 0;
       do {
               if (sfsp && count < maxcount &&
                   ((mp->mnt_flag & MNT_MLOCK) == 0)) {
                       sp = &mp->mnt_stat;
                       /*
                        * If MNT_NOWAIT is specified, do not refresh the
                        * fsstat cache. MNT_WAIT overrides MNT_NOWAIT.
                        */
                       if (((uap->flags & MNT_NOWAIT) == 0 ||
                           (uap->flags & MNT_WAIT)) &&
                           (error = VFS_STATFS(mp, sp))) {
                               mp = mp->mnt_prev;
                               continue;
                       }
                       sp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
                       if (error = copyout((caddr_t)sp, sfsp, sizeof(*sp)))
                               return (error);
                       sfsp += sizeof(*sp);
               }
               count++;
               mp = mp->mnt_prev;
       } while (mp != rootfs);
       if (sfsp && count > maxcount)
               *retval = maxcount;
       else
               *retval = count;
       return (0);
}

/*
* Change current working directory to a given file descriptor.
*/
/* ARGSUSED */
fchdir(p, uap, retval)
       struct proc *p;
       struct args {
               int     fd;
       } *uap;
       int *retval;
{
       register struct filedesc *fdp = p->p_fd;
       register struct vnode *vp;
       struct file *fp;
       int error;

       if (error = getvnode(fdp, uap->fd, &fp))
               return (error);
       vp = (struct vnode *)fp->f_data;
       VOP_LOCK(vp);
       if (vp->v_type != VDIR)
               error = ENOTDIR;
       else
               error = VOP_ACCESS(vp, VEXEC, p->p_ucred);
       VOP_UNLOCK(vp);
       if (error)
               return (error);
       VREF(vp);
       vrele(fdp->fd_cdir);
       fdp->fd_cdir = vp;
       return (0);
}

/*
* Change current working directory (``.'').
*/
/* ARGSUSED */
chdir(p, uap, retval)
       struct proc *p;
       struct args {
               char    *fname;
       } *uap;
       int *retval;
{
       register struct nameidata *ndp;
       register struct filedesc *fdp = p->p_fd;
       int error;
       struct nameidata nd;

       ndp = &nd;
       ndp->ni_nameiop = LOOKUP | FOLLOW | LOCKLEAF;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->fname;
       if (error = chdirec(ndp, p))
               return (error);
       vrele(fdp->fd_cdir);
       fdp->fd_cdir = ndp->ni_vp;
       return (0);
}

/*
* Change notion of root (``/'') directory.
*/
/* ARGSUSED */
chroot(p, uap, retval)
       struct proc *p;
       struct args {
               char    *fname;
       } *uap;
       int *retval;
{
       register struct nameidata *ndp;
       register struct filedesc *fdp = p->p_fd;
       int error;
       struct nameidata nd;

       if (error = suser(p->p_ucred, &p->p_acflag))
               return (error);
       ndp = &nd;
       ndp->ni_nameiop = LOOKUP | FOLLOW | LOCKLEAF;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->fname;
       if (error = chdirec(ndp, p))
               return (error);
       if (fdp->fd_rdir != NULL)
               vrele(fdp->fd_rdir);
       fdp->fd_rdir = ndp->ni_vp;
       return (0);
}

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

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

/*
* Open system call.
* Check permissions, allocate an open file structure,
* and call the device open routine if any.
*/
open(p, uap, retval)
       struct proc *p;
       register struct args {
               char    *fname;
               int     mode;
               int     crtmode;
       } *uap;
       int *retval;
{
       struct nameidata *ndp;
       register struct filedesc *fdp = p->p_fd;
       register struct file *fp;
       int fmode, cmode;
       struct file *nfp;
       int indx, error;
       struct nameidata nd;
       extern struct fileops vnops;

       if (error = falloc(p, &nfp, &indx))
               return (error);
       fp = nfp;
       fmode = FFLAGS(uap->mode);
       cmode = ((uap->crtmode &~ fdp->fd_cmask) & 07777) &~ S_ISVTX;
       ndp = &nd;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->fname;
       p->p_dupfd = -indx - 1;                 /* XXX check for fdopen */
       if (error = vn_open(ndp, p, fmode, cmode)) {
               crfree(fp->f_cred);
               fp->f_count--;
               if (error == ENODEV &&          /* XXX from fdopen */
                   p->p_dupfd >= 0 &&
                   (error = dupfdopen(fdp, indx, p->p_dupfd, fmode)) == 0) {
                       *retval = indx;
                       return (0);
               }
               if (error == ERESTART)
                       error = EINTR;
               fdp->fd_ofiles[indx] = NULL;
               return (error);
       }
       fp->f_flag = fmode & FMASK;
       fp->f_type = DTYPE_VNODE;
       fp->f_ops = &vnops;
       fp->f_data = (caddr_t)ndp->ni_vp;
       *retval = indx;
       return (0);
}

#ifdef COMPAT_43
/*
* Creat system call.
*/
ocreat(p, uap, retval)
       struct proc *p;
       register struct args {
               char    *fname;
               int     fmode;
       } *uap;
       int *retval;
{
       struct args {
               char    *fname;
               int     mode;
               int     crtmode;
       } openuap;

       openuap.fname = uap->fname;
       openuap.crtmode = uap->fmode;
       openuap.mode = O_WRONLY | O_CREAT | O_TRUNC;
       return (open(p, &openuap, retval));
}
#endif /* COMPAT_43 */

/*
* Mknod system call
*/
/* ARGSUSED */
mknod(p, uap, retval)
       struct proc *p;
       register struct args {
               char    *fname;
               int     fmode;
               int     dev;
       } *uap;
       int *retval;
{
       register struct nameidata *ndp;
       register struct vnode *vp;
       struct vattr vattr;
       int error;
       struct nameidata nd;

       if (error = suser(p->p_ucred, &p->p_acflag))
               return (error);
       ndp = &nd;
       ndp->ni_nameiop = CREATE | LOCKPARENT;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->fname;
       if (error = namei(ndp, p))
               return (error);
       vp = ndp->ni_vp;
       if (vp != NULL) {
               error = EEXIST;
               goto out;
       }
       VATTR_NULL(&vattr);
       switch (uap->fmode & 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;
       default:
               error = EINVAL;
               goto out;
       }
       vattr.va_mode = (uap->fmode & 07777) &~ p->p_fd->fd_cmask;
       vattr.va_rdev = uap->dev;
out:
       if (!error) {
               error = VOP_MKNOD(ndp, &vattr, p->p_ucred);
       } else {
               VOP_ABORTOP(ndp);
               if (ndp->ni_dvp == vp)
                       vrele(ndp->ni_dvp);
               else
                       vput(ndp->ni_dvp);
               if (vp)
                       vrele(vp);
       }
       return (error);
}

/*
* Mkfifo system call
*/
/* ARGSUSED */
mkfifo(p, uap, retval)
       struct proc *p;
       register struct args {
               char    *fname;
               int     fmode;
       } *uap;
       int *retval;
{
       register struct nameidata *ndp;
       struct vattr vattr;
       int error;
       struct nameidata nd;

#ifndef FIFO
       return (EOPNOTSUPP);
#else
       ndp = &nd;
       ndp->ni_nameiop = CREATE | LOCKPARENT;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->fname;
       if (error = namei(ndp, p))
               return (error);
       if (ndp->ni_vp != NULL) {
               VOP_ABORTOP(ndp);
               if (ndp->ni_dvp == ndp->ni_vp)
                       vrele(ndp->ni_dvp);
               else
                       vput(ndp->ni_dvp);
               vrele(ndp->ni_vp);
               return (EEXIST);
       }
       VATTR_NULL(&vattr);
       vattr.va_type = VFIFO;
       vattr.va_mode = (uap->fmode & 07777) &~ p->p_fd->fd_cmask;
       return (VOP_MKNOD(ndp, &vattr, p->p_ucred));
#endif /* FIFO */
}

/*
* link system call
*/
/* ARGSUSED */
link(p, uap, retval)
       struct proc *p;
       register struct args {
               char    *target;
               char    *linkname;
       } *uap;
       int *retval;
{
       register struct nameidata *ndp;
       register struct vnode *vp, *xp;
       int error;
       struct nameidata nd;

       ndp = &nd;
       ndp->ni_nameiop = LOOKUP | FOLLOW;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->target;
       if (error = namei(ndp, p))
               return (error);
       vp = ndp->ni_vp;
       if (vp->v_type == VDIR &&
           (error = suser(p->p_ucred, &p->p_acflag)))
               goto out1;
       ndp->ni_nameiop = CREATE | LOCKPARENT;
       ndp->ni_dirp = (caddr_t)uap->linkname;
       if (error = namei(ndp, p))
               goto out1;
       xp = ndp->ni_vp;
       if (xp != NULL) {
               error = EEXIST;
               goto out;
       }
       xp = ndp->ni_dvp;
       if (vp->v_mount != xp->v_mount)
               error = EXDEV;
out:
       if (!error) {
               error = VOP_LINK(vp, ndp);
       } else {
               VOP_ABORTOP(ndp);
               if (ndp->ni_dvp == ndp->ni_vp)
                       vrele(ndp->ni_dvp);
               else
                       vput(ndp->ni_dvp);
               if (ndp->ni_vp)
                       vrele(ndp->ni_vp);
       }
out1:
       vrele(vp);
       return (error);
}

/*
* symlink -- make a symbolic link
*/
/* ARGSUSED */
symlink(p, uap, retval)
       struct proc *p;
       register struct args {
               char    *target;
               char    *linkname;
       } *uap;
       int *retval;
{
       register struct nameidata *ndp;
       struct vattr vattr;
       char *target;
       int error;
       struct nameidata nd;

       ndp = &nd;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->linkname;
       MALLOC(target, char *, MAXPATHLEN, M_NAMEI, M_WAITOK);
       if (error = copyinstr(uap->target, target, MAXPATHLEN, (u_int *)0))
               goto out;
       ndp->ni_nameiop = CREATE | LOCKPARENT;
       if (error = namei(ndp, p))
               goto out;
       if (ndp->ni_vp) {
               VOP_ABORTOP(ndp);
               if (ndp->ni_dvp == ndp->ni_vp)
                       vrele(ndp->ni_dvp);
               else
                       vput(ndp->ni_dvp);
               vrele(ndp->ni_vp);
               error = EEXIST;
               goto out;
       }
       VATTR_NULL(&vattr);
       vattr.va_mode = 0777 &~ p->p_fd->fd_cmask;
       error = VOP_SYMLINK(ndp, &vattr, target);
out:
       FREE(target, M_NAMEI);
       return (error);
}

/*
* Unlink system call.
* Hard to avoid races here, especially
* in unlinking directories.
*/
/* ARGSUSED */
unlink(p, uap, retval)
       struct proc *p;
       struct args {
               char    *fname;
       } *uap;
       int *retval;
{
       register struct nameidata *ndp;
       register struct vnode *vp;
       int error;
       struct nameidata nd;

       ndp = &nd;
       ndp->ni_nameiop = DELETE | LOCKPARENT | LOCKLEAF;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->fname;
       if (error = namei(ndp, p))
               return (error);
       vp = ndp->ni_vp;
       if (vp->v_type == VDIR &&
           (error = suser(p->p_ucred, &p->p_acflag)))
               goto out;
       /*
        * Don't unlink a mounted file.
        */
       if (vp->v_flag & VROOT) {
               error = EBUSY;
               goto out;
       }
#ifdef NVM
       (void) vnode_pager_uncache(vp);
#else
       if (vp->v_flag & VTEXT)
               xrele(vp);      /* try once to free text */
#endif
out:
       if (!error) {
               error = VOP_REMOVE(ndp);
       } else {
               VOP_ABORTOP(ndp);
               if (ndp->ni_dvp == vp)
                       vrele(ndp->ni_dvp);
               else
                       vput(ndp->ni_dvp);
               vput(vp);
       }
       return (error);
}

/*
* Seek system call
*/
lseek(p, uap, retval)
       struct proc *p;
       register struct args {
               int     fdes;
               off_t   off;
               int     sbase;
       } *uap;
       off_t *retval;
{
       struct ucred *cred = p->p_ucred;
       register struct filedesc *fdp = p->p_fd;
       register struct file *fp;
       struct vattr vattr;
       int error;

       if ((unsigned)uap->fdes >= fdp->fd_nfiles ||
           (fp = fdp->fd_ofiles[uap->fdes]) == NULL)
               return (EBADF);
       if (fp->f_type != DTYPE_VNODE)
               return (ESPIPE);
       switch (uap->sbase) {

       case L_INCR:
               fp->f_offset += uap->off;
               break;

       case L_XTND:
               if (error = VOP_GETATTR((struct vnode *)fp->f_data,
                   &vattr, cred))
                       return (error);
               fp->f_offset = uap->off + vattr.va_size;
               break;

       case L_SET:
               fp->f_offset = uap->off;
               break;

       default:
               return (EINVAL);
       }
       *retval = fp->f_offset;
       return (0);
}

/*
* Access system call
*/
/* ARGSUSED */
saccess(p, uap, retval)
       struct proc *p;
       register struct args {
               char    *fname;
               int     fmode;
       } *uap;
       int *retval;
{
       register struct nameidata *ndp;
       register struct ucred *cred = p->p_ucred;
       register struct vnode *vp;
       int error, mode, svuid, svgid;
       struct nameidata nd;

       ndp = &nd;
       svuid = cred->cr_uid;
       svgid = cred->cr_groups[0];
       cred->cr_uid = p->p_cred->p_ruid;
       cred->cr_groups[0] = p->p_cred->p_rgid;
       ndp->ni_nameiop = LOOKUP | FOLLOW | LOCKLEAF;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->fname;
       if (error = namei(ndp, p))
               goto out1;
       vp = ndp->ni_vp;
       /*
        * fmode == 0 means only check for exist
        */
       if (uap->fmode) {
               mode = 0;
               if (uap->fmode & R_OK)
                       mode |= VREAD;
               if (uap->fmode & W_OK)
                       mode |= VWRITE;
               if (uap->fmode & X_OK)
                       mode |= VEXEC;
               if ((mode & VWRITE) == 0 || (error = vn_writechk(vp)) == 0)
                       error = VOP_ACCESS(vp, mode, cred);
       }
       vput(vp);
out1:
       cred->cr_uid = svuid;
       cred->cr_groups[0] = svgid;
       return (error);
}

/*
* Stat system call.  This version follows links.
*/
/* ARGSUSED */
stat(p, uap, retval)
       struct proc *p;
       register struct args {
               char    *fname;
               struct stat *ub;
       } *uap;
       int *retval;
{
       register struct nameidata *ndp;
       struct stat sb;
       int error;
       struct nameidata nd;

       ndp = &nd;
       ndp->ni_nameiop = LOOKUP | LOCKLEAF | FOLLOW;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->fname;
       if (error = namei(ndp, p))
               return (error);
       error = vn_stat(ndp->ni_vp, &sb);
       vput(ndp->ni_vp);
       if (error)
               return (error);
       error = copyout((caddr_t)&sb, (caddr_t)uap->ub, sizeof (sb));
       return (error);
}

/*
* Lstat system call.  This version does not follow links.
*/
/* ARGSUSED */
lstat(p, uap, retval)
       struct proc *p;
       register struct args {
               char    *fname;
               struct stat *ub;
       } *uap;
       int *retval;
{
       register struct nameidata *ndp;
       struct stat sb;
       int error;
       struct nameidata nd;

       ndp = &nd;
       ndp->ni_nameiop = LOOKUP | LOCKLEAF | NOFOLLOW;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->fname;
       if (error = namei(ndp, p))
               return (error);
       error = vn_stat(ndp->ni_vp, &sb);
       vput(ndp->ni_vp);
       if (error)
               return (error);
       error = copyout((caddr_t)&sb, (caddr_t)uap->ub, sizeof (sb));
       return (error);
}

/*
* Return target name of a symbolic link
*/
/* ARGSUSED */
readlink(p, uap, retval)
       struct proc *p;
       register struct args {
               char    *name;
               char    *buf;
               int     count;
       } *uap;
       int *retval;
{
       register struct nameidata *ndp;
       register struct vnode *vp;
       struct iovec aiov;
       struct uio auio;
       int error;
       struct nameidata nd;

       ndp = &nd;
       ndp->ni_nameiop = LOOKUP | LOCKLEAF;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->name;
       if (error = namei(ndp, p))
               return (error);
       vp = ndp->ni_vp;
       if (vp->v_type != VLNK) {
               error = EINVAL;
               goto out;
       }
       aiov.iov_base = uap->buf;
       aiov.iov_len = uap->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_resid = uap->count;
       error = VOP_READLINK(vp, &auio, p->p_ucred);
out:
       vput(vp);
       *retval = uap->count - auio.uio_resid;
       return (error);
}

/*
* Change flags of a file given path name.
*/
/* ARGSUSED */
chflags(p, uap, retval)
       struct proc *p;
       register struct args {
               char    *fname;
               int     flags;
       } *uap;
       int *retval;
{
       register struct nameidata *ndp;
       register struct vnode *vp;
       struct vattr vattr;
       int error;
       struct nameidata nd;

       ndp = &nd;
       ndp->ni_nameiop = LOOKUP | FOLLOW | LOCKLEAF;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->fname;
       if (error = namei(ndp, p))
               return (error);
       vp = ndp->ni_vp;
       if (vp->v_mount->mnt_flag & MNT_RDONLY) {
               error = EROFS;
               goto out;
       }
       VATTR_NULL(&vattr);
       vattr.va_flags = uap->flags;
       error = VOP_SETATTR(vp, &vattr, p->p_ucred);
out:
       vput(vp);
       return (error);
}

/*
* Change flags of a file given a file descriptor.
*/
/* ARGSUSED */
fchflags(p, uap, retval)
       struct proc *p;
       register struct args {
               int     fd;
               int     flags;
       } *uap;
       int *retval;
{
       struct vattr vattr;
       struct vnode *vp;
       struct file *fp;
       int error;

       if (error = getvnode(p->p_fd, uap->fd, &fp))
               return (error);
       vp = (struct vnode *)fp->f_data;
       VOP_LOCK(vp);
       if (vp->v_mount->mnt_flag & MNT_RDONLY) {
               error = EROFS;
               goto out;
       }
       VATTR_NULL(&vattr);
       vattr.va_flags = uap->flags;
       error = VOP_SETATTR(vp, &vattr, p->p_ucred);
out:
       VOP_UNLOCK(vp);
       return (error);
}

/*
* Change mode of a file given path name.
*/
/* ARGSUSED */
chmod(p, uap, retval)
       struct proc *p;
       register struct args {
               char    *fname;
               int     fmode;
       } *uap;
       int *retval;
{
       register struct nameidata *ndp;
       register struct vnode *vp;
       struct vattr vattr;
       int error;
       struct nameidata nd;

       ndp = &nd;
       ndp->ni_nameiop = LOOKUP | FOLLOW | LOCKLEAF;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->fname;
       if (error = namei(ndp, p))
               return (error);
       vp = ndp->ni_vp;
       if (vp->v_mount->mnt_flag & MNT_RDONLY) {
               error = EROFS;
               goto out;
       }
       VATTR_NULL(&vattr);
       vattr.va_mode = uap->fmode & 07777;
       error = VOP_SETATTR(vp, &vattr, p->p_ucred);
out:
       vput(vp);
       return (error);
}

/*
* Change mode of a file given a file descriptor.
*/
/* ARGSUSED */
fchmod(p, uap, retval)
       struct proc *p;
       register struct args {
               int     fd;
               int     fmode;
       } *uap;
       int *retval;
{
       struct vattr vattr;
       struct vnode *vp;
       struct file *fp;
       int error;

       if (error = getvnode(p->p_fd, uap->fd, &fp))
               return (error);
       vp = (struct vnode *)fp->f_data;
       VOP_LOCK(vp);
       if (vp->v_mount->mnt_flag & MNT_RDONLY) {
               error = EROFS;
               goto out;
       }
       VATTR_NULL(&vattr);
       vattr.va_mode = uap->fmode & 07777;
       error = VOP_SETATTR(vp, &vattr, p->p_ucred);
out:
       VOP_UNLOCK(vp);
       return (error);
}

/*
* Set ownership given a path name.
*/
/* ARGSUSED */
chown(p, uap, retval)
       struct proc *p;
       register struct args {
               char    *fname;
               int     uid;
               int     gid;
       } *uap;
       int *retval;
{
       register struct nameidata *ndp;
       register struct vnode *vp;
       struct vattr vattr;
       int error;
       struct nameidata nd;

       ndp = &nd;
       ndp->ni_nameiop = LOOKUP | NOFOLLOW | LOCKLEAF;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->fname;
       if (error = namei(ndp, p))
               return (error);
       vp = ndp->ni_vp;
       if (vp->v_mount->mnt_flag & MNT_RDONLY) {
               error = EROFS;
               goto out;
       }
       VATTR_NULL(&vattr);
       vattr.va_uid = uap->uid;
       vattr.va_gid = uap->gid;
       error = VOP_SETATTR(vp, &vattr, p->p_ucred);
out:
       vput(vp);
       return (error);
}

/*
* Set ownership given a file descriptor.
*/
/* ARGSUSED */
fchown(p, uap, retval)
       struct proc *p;
       register struct args {
               int     fd;
               int     uid;
               int     gid;
       } *uap;
       int *retval;
{
       struct vattr vattr;
       struct vnode *vp;
       struct file *fp;
       int error;

       if (error = getvnode(p->p_fd, uap->fd, &fp))
               return (error);
       vp = (struct vnode *)fp->f_data;
       VOP_LOCK(vp);
       if (vp->v_mount->mnt_flag & MNT_RDONLY) {
               error = EROFS;
               goto out;
       }
       VATTR_NULL(&vattr);
       vattr.va_uid = uap->uid;
       vattr.va_gid = uap->gid;
       error = VOP_SETATTR(vp, &vattr, p->p_ucred);
out:
       VOP_UNLOCK(vp);
       return (error);
}

/*
* Set the access and modification times of a file.
*/
/* ARGSUSED */
utimes(p, uap, retval)
       struct proc *p;
       register struct args {
               char    *fname;
               struct  timeval *tptr;
       } *uap;
       int *retval;
{
       register struct nameidata *ndp;
       register struct vnode *vp;
       struct timeval tv[2];
       struct vattr vattr;
       int error;
       struct nameidata nd;

       if (error = copyin((caddr_t)uap->tptr, (caddr_t)tv, sizeof (tv)))
               return (error);
       ndp = &nd;
       ndp->ni_nameiop = LOOKUP | FOLLOW | LOCKLEAF;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->fname;
       if (error = namei(ndp, p))
               return (error);
       vp = ndp->ni_vp;
       if (vp->v_mount->mnt_flag & MNT_RDONLY) {
               error = EROFS;
               goto out;
       }
       VATTR_NULL(&vattr);
       vattr.va_atime = tv[0];
       vattr.va_mtime = tv[1];
       error = VOP_SETATTR(vp, &vattr, p->p_ucred);
out:
       vput(vp);
       return (error);
}

/*
* Truncate a file given its path name.
*/
/* ARGSUSED */
truncate(p, uap, retval)
       struct proc *p;
       register struct args {
               char    *fname;
               off_t   length;
       } *uap;
       int *retval;
{
       register struct nameidata *ndp;
       register struct vnode *vp;
       struct vattr vattr;
       int error;
       struct nameidata nd;

       ndp = &nd;
       ndp->ni_nameiop = LOOKUP | FOLLOW | LOCKLEAF;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->fname;
       if (error = namei(ndp, p))
               return (error);
       vp = ndp->ni_vp;
       if (vp->v_type == VDIR) {
               error = EISDIR;
               goto out;
       }
       if ((error = vn_writechk(vp)) ||
           (error = VOP_ACCESS(vp, VWRITE, p->p_ucred)))
               goto out;
       VATTR_NULL(&vattr);
       vattr.va_size = uap->length;
       error = VOP_SETATTR(vp, &vattr, p->p_ucred);
out:
       vput(vp);
       return (error);
}

/*
* Truncate a file given a file descriptor.
*/
/* ARGSUSED */
ftruncate(p, uap, retval)
       struct proc *p;
       register struct args {
               int     fd;
               off_t   length;
       } *uap;
       int *retval;
{
       struct vattr vattr;
       struct vnode *vp;
       struct file *fp;
       int error;

       if (error = getvnode(p->p_fd, uap->fd, &fp))
               return (error);
       if ((fp->f_flag & FWRITE) == 0)
               return (EINVAL);
       vp = (struct vnode *)fp->f_data;
       VOP_LOCK(vp);
       if (vp->v_type == VDIR) {
               error = EISDIR;
               goto out;
       }
       if (error = vn_writechk(vp))
               goto out;
       VATTR_NULL(&vattr);
       vattr.va_size = uap->length;
       error = VOP_SETATTR(vp, &vattr, fp->f_cred);
out:
       VOP_UNLOCK(vp);
       return (error);
}

/*
* Synch an open file.
*/
/* ARGSUSED */
fsync(p, uap, retval)
       struct proc *p;
       struct args {
               int     fd;
       } *uap;
       int *retval;
{
       register struct vnode *vp;
       struct file *fp;
       int error;

       if (error = getvnode(p->p_fd, uap->fd, &fp))
               return (error);
       vp = (struct vnode *)fp->f_data;
       VOP_LOCK(vp);
       error = VOP_FSYNC(vp, fp->f_flag, fp->f_cred, MNT_WAIT);
       VOP_UNLOCK(vp);
       return (error);
}

/*
* Rename system call.
*
* Source and destination must either both be directories, or both
* not be directories.  If target is a directory, it must be empty.
*/
/* ARGSUSED */
rename(p, uap, retval)
       struct proc *p;
       register struct args {
               char    *from;
               char    *to;
       } *uap;
       int *retval;
{
       register struct vnode *tvp, *fvp, *tdvp;
       register struct nameidata *ndp;
       int error;
       struct nameidata nd, tond;

       ndp = &nd;
       ndp->ni_nameiop = DELETE | WANTPARENT;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->from;
       if (error = namei(ndp, p))
               return (error);
       fvp = ndp->ni_vp;
       nddup(ndp, &tond);
       tond.ni_nameiop = RENAME | LOCKPARENT | LOCKLEAF | NOCACHE;
       tond.ni_segflg = UIO_USERSPACE;
       tond.ni_dirp = uap->to;
       if (error = namei(&tond, p)) {
               VOP_ABORTOP(ndp);
               vrele(ndp->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->v_mount != tvp->v_mount) {
                       error = EXDEV;
                       goto out;
               }
       }
       if (fvp->v_mount != tdvp->v_mount) {
               error = EXDEV;
               goto out;
       }
       if (fvp == tdvp)
               error = EINVAL;
       /*
        * If source is the same as the destination,
        * then there is nothing to do.
        */
       if (fvp == tvp)
               error = -1;
out:
       if (!error) {
               error = VOP_RENAME(ndp, &tond);
       } else {
               VOP_ABORTOP(&tond);
               if (tdvp == tvp)
                       vrele(tdvp);
               else
                       vput(tdvp);
               if (tvp)
                       vput(tvp);
               VOP_ABORTOP(ndp);
               vrele(ndp->ni_dvp);
               vrele(fvp);
       }
out1:
       ndrele(&tond);
       if (error == -1)
               return (0);
       return (error);
}

/*
* Mkdir system call
*/
/* ARGSUSED */
mkdir(p, uap, retval)
       struct proc *p;
       register struct args {
               char    *name;
               int     dmode;
       } *uap;
       int *retval;
{
       register struct nameidata *ndp;
       register struct vnode *vp;
       struct vattr vattr;
       int error;
       struct nameidata nd;

       ndp = &nd;
       ndp->ni_nameiop = CREATE | LOCKPARENT;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->name;
       if (error = namei(ndp, p))
               return (error);
       vp = ndp->ni_vp;
       if (vp != NULL) {
               VOP_ABORTOP(ndp);
               if (ndp->ni_dvp == vp)
                       vrele(ndp->ni_dvp);
               else
                       vput(ndp->ni_dvp);
               vrele(vp);
               return (EEXIST);
       }
       VATTR_NULL(&vattr);
       vattr.va_type = VDIR;
       vattr.va_mode = (uap->dmode & 0777) &~ p->p_fd->fd_cmask;
       error = VOP_MKDIR(ndp, &vattr);
       if (!error)
               vput(ndp->ni_vp);
       return (error);
}

/*
* Rmdir system call.
*/
/* ARGSUSED */
rmdir(p, uap, retval)
       struct proc *p;
       struct args {
               char    *name;
       } *uap;
       int *retval;
{
       register struct nameidata *ndp;
       register struct vnode *vp;
       int error;
       struct nameidata nd;

       ndp = &nd;
       ndp->ni_nameiop = DELETE | LOCKPARENT | LOCKLEAF;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->name;
       if (error = namei(ndp, p))
               return (error);
       vp = ndp->ni_vp;
       if (vp->v_type != VDIR) {
               error = ENOTDIR;
               goto out;
       }
       /*
        * No rmdir "." please.
        */
       if (ndp->ni_dvp == vp) {
               error = EINVAL;
               goto out;
       }
       /*
        * Don't unlink a mounted file.
        */
       if (vp->v_flag & VROOT)
               error = EBUSY;
out:
       if (!error) {
               error = VOP_RMDIR(ndp);
       } else {
               VOP_ABORTOP(ndp);
               if (ndp->ni_dvp == vp)
                       vrele(ndp->ni_dvp);
               else
                       vput(ndp->ni_dvp);
               vput(vp);
       }
       return (error);
}

/*
* Read a block of directory entries in a file system independent format
*/
getdirentries(p, uap, retval)
       struct proc *p;
       register struct args {
               int     fd;
               char    *buf;
               unsigned count;
               long    *basep;
       } *uap;
       int *retval;
{
       register struct vnode *vp;
       struct file *fp;
       struct uio auio;
       struct iovec aiov;
       off_t off;
       int error, eofflag;

       if (error = getvnode(p->p_fd, uap->fd, &fp))
               return (error);
       if ((fp->f_flag & FREAD) == 0)
               return (EBADF);
       vp = (struct vnode *)fp->f_data;
       if (vp->v_type != VDIR)
               return (EINVAL);
       aiov.iov_base = uap->buf;
       aiov.iov_len = uap->count;
       auio.uio_iov = &aiov;
       auio.uio_iovcnt = 1;
       auio.uio_rw = UIO_READ;
       auio.uio_segflg = UIO_USERSPACE;
       auio.uio_resid = uap->count;
       VOP_LOCK(vp);
       auio.uio_offset = off = fp->f_offset;
       error = VOP_READDIR(vp, &auio, fp->f_cred, &eofflag);
       fp->f_offset = auio.uio_offset;
       VOP_UNLOCK(vp);
       if (error)
               return (error);
       error = copyout((caddr_t)&off, (caddr_t)uap->basep, sizeof(long));
       *retval = uap->count - auio.uio_resid;
       return (error);
}

/*
* mode mask for creation of files
*/
mode_t
umask(p, uap, retval)
       struct proc *p;
       struct args {
               int     mask;
       } *uap;
       int *retval;
{
       register struct filedesc *fdp = p->p_fd;

       *retval = fdp->fd_cmask;
       fdp->fd_cmask = uap->mask & 07777;
       return (0);
}

/*
* Void all references to file by ripping underlying filesystem
* away from vnode.
*/
/* ARGSUSED */
revoke(p, uap, retval)
       struct proc *p;
       register struct args {
               char    *fname;
       } *uap;
       int *retval;
{
       register struct nameidata *ndp;
       register struct vnode *vp;
       struct vattr vattr;
       int error;
       struct nameidata nd;

       ndp = &nd;
       ndp->ni_nameiop = LOOKUP | FOLLOW;
       ndp->ni_segflg = UIO_USERSPACE;
       ndp->ni_dirp = uap->fname;
       if (error = namei(ndp, p))
               return (error);
       vp = ndp->ni_vp;
       if (vp->v_type != VCHR && vp->v_type != VBLK) {
               error = EINVAL;
               goto out;
       }
       if (error = VOP_GETATTR(vp, &vattr, p->p_ucred))
               goto out;
       if (p->p_ucred->cr_uid != vattr.va_uid &&
           (error = suser(p->p_ucred, &p->p_acflag)))
               goto out;
       if (vp->v_usecount > 1 || (vp->v_flag & VALIASED))
               vgoneall(vp);
out:
       vrele(vp);
       return (error);
}

getvnode(fdp, fdes, fpp)
       struct filedesc *fdp;
       struct file **fpp;
       int fdes;
{
       struct file *fp;

       if ((unsigned)fdes >= fdp->fd_nfiles ||
           (fp = fdp->fd_ofiles[fdes]) == NULL)
               return (EBADF);
       if (fp->f_type != DTYPE_VNODE)
               return (EINVAL);
       *fpp = fp;
       return (0);
}