xnu-201.tar.gz

[apple/xnu.git] / bsd / kern / kern_descrip.c

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1995, 1997 Apple Computer, Inc. All Rights Reserved */
/*
 * Copyright (c) 1982, 1986, 1989, 1991, 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. 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.
 *
 *      @(#)kern_descrip.c      8.8 (Berkeley) 2/14/95
 *
 *     History:
 *              CHW     8/5/98    Added F_SETSIZE command to truncate without
 *                                      zero filling space 
 *              CHW     7/6/98    Updated Preallocate command to take a structure
 *                                and return output.
 *              CHW     6/25/98   Fixed a bug in the lock call in fcntl 
 *                                Preallocate command
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/filedesc.h>
#include <sys/kernel.h>
#include <sys/vnode.h>
#include <sys/proc.h>
#include <sys/file.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/fcntl.h>
#include <sys/malloc.h>
#include <sys/syslog.h>
#include <sys/unistd.h>
#include <sys/resourcevar.h>

#include <sys/mount.h>

/*
 * Descriptor management.
 */
struct filelist filehead;       /* head of list of open files */
int nfiles;                     /* actual number of open files */

/*
 * System calls on descriptors.
 */
/* ARGSUSED */
int
getdtablesize(p, uap, retval)
        struct proc *p;
        void *uap;
        register_t *retval;
{

        *retval = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles);
        return (0);
}

/* ARGSUSED */
int
ogetdtablesize(p, uap, retval)
        struct proc *p;
        void *uap;
        register_t *retval;
{

        *retval = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, NOFILE);
        return (0);
}

static __inline__
void _fdrelse(fdp, fd)
        register struct filedesc *fdp;
        register int fd;
{
        if (fd < fdp->fd_freefile)
                fdp->fd_freefile = fd;
#if DIAGNOSTIC
        if (fd > fdp->fd_lastfile)
                panic("fdrelse: fd_lastfile inconsistent");
#endif
        fdp->fd_ofiles[fd] = NULL;
        fdp->fd_ofileflags[fd] = 0;
        while ((fd = fdp->fd_lastfile) > 0 &&
                        fdp->fd_ofiles[fd] == NULL &&
                        !(fdp->fd_ofileflags[fd] & UF_RESERVED))
                fdp->fd_lastfile--;
}

/*
 * Duplicate a file descriptor.
 */
struct dup_args {
        u_int   fd;
};
/* ARGSUSED */
int
dup(p, uap, retval)
        struct proc *p;
        struct dup_args *uap;
        register_t *retval;
{
        register struct filedesc *fdp = p->p_fd;
        register int old = uap->fd;
        int new, error;

        if ((u_int)old >= fdp->fd_nfiles ||
                        fdp->fd_ofiles[old] == NULL ||
                        (fdp->fd_ofileflags[old] & UF_RESERVED))
                return (EBADF);
        if (error = fdalloc(p, 0, &new))
                return (error);
        return (finishdup(fdp, old, new, retval));
}

/*
 * Duplicate a file descriptor to a particular value.
 */
struct dup2_args {
        u_int   from;
        u_int   to;
};
/* ARGSUSED */
int
dup2(p, uap, retval)
        struct proc *p;
        struct dup2_args *uap;
        register_t *retval;
{
        register struct filedesc *fdp = p->p_fd;
        register int old = uap->from, new = uap->to;
        int i, error;

        if ((u_int)old >= fdp->fd_nfiles ||
                fdp->fd_ofiles[old] == NULL ||
                (fdp->fd_ofileflags[old] & UF_RESERVED) ||
            (u_int)new >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur ||
            (u_int)new >= maxfiles)
                return (EBADF);
        if (old == new) {
                *retval = new;
                return (0);
        }
        if ((u_int)new >= fdp->fd_nfiles) {
                if (error = fdalloc(p, new, &i))
                        return (error);
                if (new != i) {
                        _fdrelse(fdp, i);
                        goto closeit;
                }
        }
        else {
                struct file **fpp;
                char flags;
closeit:
                if ((flags = fdp->fd_ofileflags[new]) & UF_RESERVED)
                        return (EBADF);
                fdp->fd_ofileflags[new] = (flags & ~UF_MAPPED) | UF_RESERVED;
                /*
                 * dup2() must succeed even if the close has an error.
                 */
                if (*(fpp = &fdp->fd_ofiles[new])) {
                        struct file *fp = *fpp;

                        *fpp = NULL; (void) closef(fp, p);
                }
        }
        return (finishdup(fdp, old, new, retval));
}

/*
 * The file control system call.
 */
struct fcntl_args {
        int     fd;
        int     cmd;
        int     arg;
};
/* ARGSUSED */
int
fcntl(p, uap, retval)
        struct proc *p;
        register struct fcntl_args *uap;
        register_t *retval;
{
        int fd = uap->fd;
        register struct filedesc *fdp = p->p_fd;
        register struct file *fp;
        register char *pop;
        struct vnode *vp, *devvp;
        int i, tmp, error, error2, flg = F_POSIX;
        struct flock fl;
        fstore_t alloc_struct;    /* structure for allocate command */
        u_int32_t alloc_flags = 0;
        off_t offset;             /* used for F_SETSIZE */
        int newmin;
        struct radvisory ra_struct;
        fbootstraptransfer_t fbt_struct; /* for F_READBOOTSTRAP and F_WRITEBOOTSTRAP */
        struct log2phys l2p_struct;    /* structure for allocate command */
        daddr_t lbn, bn;
        int devBlockSize = 0;

        if ((u_int)fd >= fdp->fd_nfiles ||
                        (fp = fdp->fd_ofiles[fd]) == NULL ||
                        (fdp->fd_ofileflags[fd] & UF_RESERVED))
                return (EBADF);
        pop = &fdp->fd_ofileflags[fd];
        switch (uap->cmd) {

        case F_DUPFD:
                newmin = (long)uap->arg;
                if ((u_int)newmin >= p->p_rlimit[RLIMIT_NOFILE].rlim_cur ||
                    (u_int)newmin >= maxfiles)
                        return (EINVAL);
                if (error = fdalloc(p, newmin, &i))
                        return (error);
                return (finishdup(fdp, fd, i, retval));

        case F_GETFD:
                *retval = (*pop & UF_EXCLOSE)? 1 : 0;
                return (0);

        case F_SETFD:
                *pop = (*pop &~ UF_EXCLOSE) |
                        ((long)(uap->arg) & 1)? UF_EXCLOSE : 0;
                return (0);

        case F_GETFL:
                *retval = OFLAGS(fp->f_flag);
                return (0);

        case F_SETFL:
                fp->f_flag &= ~FCNTLFLAGS;
                fp->f_flag |= FFLAGS((long)uap->arg) & FCNTLFLAGS;
                tmp = fp->f_flag & FNONBLOCK;
                error = (*fp->f_ops->fo_ioctl)(fp, FIONBIO, (caddr_t)&tmp, p);
                if (error)
                        return (error);
                tmp = fp->f_flag & FASYNC;
                error = (*fp->f_ops->fo_ioctl)(fp, FIOASYNC, (caddr_t)&tmp, p);
                if (!error)
                        return (0);
                fp->f_flag &= ~FNONBLOCK;
                tmp = 0;
                (void) (*fp->f_ops->fo_ioctl)(fp, FIONBIO, (caddr_t)&tmp, p);
                return (error);

        case F_GETOWN:
                if (fp->f_type == DTYPE_SOCKET) {
                        *retval = ((struct socket *)fp->f_data)->so_pgid;
                        return (0);
                }
                error = (*fp->f_ops->fo_ioctl)
                        (fp, (int)TIOCGPGRP, (caddr_t)retval, p);
                *retval = -*retval;
                return (error);

        case F_SETOWN:
                if (fp->f_type == DTYPE_SOCKET) {
                        ((struct socket *)fp->f_data)->so_pgid =
                            (long)uap->arg;
                        return (0);
                }
                if ((long)uap->arg <= 0) {
                        uap->arg = (void *)(-(long)(uap->arg));
                } else {
                        struct proc *p1 = pfind((long)uap->arg);
                        if (p1 == 0)
                                return (ESRCH);
                        uap->arg = (void *)(long)p1->p_pgrp->pg_id;
                }
                return ((*fp->f_ops->fo_ioctl)
                        (fp, (int)TIOCSPGRP, (caddr_t)&uap->arg, p));

        case F_SETLKW:
                flg |= F_WAIT;
                /* Fall into F_SETLK */

        case F_SETLK:
                if (fp->f_type != DTYPE_VNODE)
                        return (EBADF);
                vp = (struct vnode *)fp->f_data;
                /* Copy in the lock structure */
                error = copyin((caddr_t)uap->arg, (caddr_t)&fl,
                    sizeof (fl));
                if (error)
                        return (error);
                if (fl.l_whence == SEEK_CUR)
                        fl.l_start += fp->f_offset;
                switch (fl.l_type) {

                case F_RDLCK:
                        if ((fp->f_flag & FREAD) == 0)
                                return (EBADF);
                        p->p_flag |= P_ADVLOCK;
                        return (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &fl, flg));

                case F_WRLCK:
                        if ((fp->f_flag & FWRITE) == 0)
                                return (EBADF);
                        p->p_flag |= P_ADVLOCK;
                        return (VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &fl, flg));

                case F_UNLCK:
                        return (VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &fl,
                                F_POSIX));

                default:
                        return (EINVAL);
                }

        case F_GETLK:
                if (fp->f_type != DTYPE_VNODE)
                        return (EBADF);
                vp = (struct vnode *)fp->f_data;
                /* Copy in the lock structure */
                error = copyin((caddr_t)uap->arg, (caddr_t)&fl,
                    sizeof (fl));
                if (error)
                        return (error);
                if (fl.l_whence == SEEK_CUR)
                        fl.l_start += fp->f_offset;
                if (error = VOP_ADVLOCK(vp, (caddr_t)p, F_GETLK, &fl, F_POSIX))
                        return (error);
                return (copyout((caddr_t)&fl, (caddr_t)uap->arg,
                    sizeof (fl)));

        case F_PREALLOCATE:
                
                /* Copy in the structure */

                error = copyin((caddr_t)uap->arg, (caddr_t)&alloc_struct,
                    sizeof (alloc_struct));

                if (error)
                        return (error);

                /* now set the space allocated to 0 and pass it out in
                   case we get a parameter checking error */
                
                alloc_struct.fst_bytesalloc = 0;
                
                error = copyout((caddr_t)&alloc_struct, (caddr_t)uap->arg,
                    sizeof (alloc_struct));

                        if (error)
                                return(error);

                /* First make sure that we have write permission */

                if ((fp->f_flag & FWRITE) == 0)
                        return (EBADF);


                /* Do some simple parameter checking */


                /* set up the flags */

                alloc_flags |= PREALLOCATE;
                
                if (alloc_struct.fst_flags & F_ALLOCATECONTIG) {
                        alloc_flags |= ALLOCATECONTIG;
                }

                if (alloc_struct.fst_flags & F_ALLOCATEALL) {
                        alloc_flags |= ALLOCATEALL;
                }

                /* Do any position mode specific stuff.  The only   */
                /* position mode  supported now is PEOFPOSMODE      */

                switch (alloc_struct.fst_posmode) {
        
                case F_PEOFPOSMODE:

                        if (alloc_struct.fst_offset != 0)
                                return (EINVAL);

                        alloc_flags |= ALLOCATEFROMPEOF;
                        break;

                case F_VOLPOSMODE:

                        if (alloc_struct.fst_offset <= 0)
                                return (EINVAL);

                        alloc_flags |= ALLOCATEFROMVOL;
                        break;

                default:

                        return(EINVAL);

                }

                /* Now lock the vnode and call allocate to get the space */

                vp = (struct vnode *)fp->f_data;

                VOP_LOCK(vp,LK_EXCLUSIVE,p);
                error = VOP_ALLOCATE(vp,alloc_struct.fst_length,alloc_flags,
                                     &alloc_struct.fst_bytesalloc, alloc_struct.fst_offset,
                                     fp->f_cred, p);
                VOP_UNLOCK(vp,0,p);

                if (error2 = (copyout((caddr_t)&alloc_struct, (caddr_t)uap->arg,
                    sizeof (alloc_struct)))) {
                        if (error) {
                                return(error);
                        } else {
                                return(error2);
                        }
                }

                return(error);
                
        case F_SETSIZE:
                
                /* Copy in the structure */

                error = copyin((caddr_t)uap->arg, (caddr_t)&offset,
                    sizeof (off_t));

                if (error)
                        return (error);


                /* First make sure that we are root.  Growing a file */
                /* without zero filling the data is a security hole  */
                /* root would have access anyway so we'll allow it   */

                if (!is_suser()) {
                        return (EACCES);
                        }

                /* Now lock the vnode and call allocate to get the space */

                vp = (struct vnode *)fp->f_data;

                VOP_LOCK(vp,LK_EXCLUSIVE,p);
                error = VOP_TRUNCATE(vp,offset,IO_NOZEROFILL,fp->f_cred,p);
                VOP_UNLOCK(vp,0,p);

                return(error);
                
        case F_RDAHEAD:
                vp = (struct vnode *)fp->f_data;
          
                simple_lock(&vp->v_interlock);
                if (uap->arg)
                      vp->v_flag &= ~VRAOFF;
                else
                      vp->v_flag |= VRAOFF;
                simple_unlock(&vp->v_interlock);

                return (0);

        case F_NOCACHE:
                vp = (struct vnode *)fp->f_data;
          
                simple_lock(&vp->v_interlock);
                if (uap->arg)
                        vp->v_flag |= VNOCACHE_DATA;
                else
                        vp->v_flag &= ~VNOCACHE_DATA;
                simple_unlock(&vp->v_interlock);

                return (0);

        case F_RDADVISE:
                vp = (struct vnode *)fp->f_data;

                if (error = copyin((caddr_t)uap->arg, (caddr_t)&ra_struct, sizeof (ra_struct)))
                        return(error);
                return (VOP_IOCTL(vp, 1, &ra_struct, 0, fp->f_cred, p));
                
        case F_READBOOTSTRAP:
        case F_WRITEBOOTSTRAP:
                
                /* Copy in the structure */

                error = copyin((caddr_t)uap->arg, (caddr_t)&fbt_struct,
                    sizeof (fbt_struct));

                if (error)
                        return (error);


                if (uap->cmd == F_WRITEBOOTSTRAP) {
                  /* First make sure that we are root.  Updating the */
                  /* bootstrap on a disk could be a security hole */

                  if (!is_suser()) {
                    return (EACCES);
                  }
                };

                /* Now lock the vnode and call VOP_IOCTL to handle the I/O: */

                vp = (struct vnode *)fp->f_data;
                if (vp->v_tag != VT_HFS) {
                  error = EINVAL;
                } else {
                  VOP_LOCK(vp,LK_EXCLUSIVE,p);
                  error = VOP_IOCTL(vp, (uap->cmd == F_WRITEBOOTSTRAP) ? 3 : 2, &fbt_struct, 0, fp->f_cred, p);
                  VOP_UNLOCK(vp,0,p);
                };

                return(error);
                
        case F_LOG2PHYS:
                if (fp->f_type != DTYPE_VNODE)
                        return (EBADF);
                vp = (struct vnode *)fp->f_data;
                VOP_LOCK(vp, LK_EXCLUSIVE, p);
                if (VOP_OFFTOBLK(vp, fp->f_offset, &lbn))
                        panic("fcntl LOG2PHYS OFFTOBLK");
                if (VOP_BLKTOOFF(vp, lbn, &offset))
                        panic("fcntl LOG2PHYS BLKTOOFF1");
                error = VOP_BMAP(vp, lbn, &devvp, &bn, 0);
                VOP_DEVBLOCKSIZE(devvp, &devBlockSize);
                VOP_UNLOCK(vp, 0, p);
                if (!error) {
                        l2p_struct.l2p_flags = 0;       /* for now */
                        l2p_struct.l2p_contigbytes = 0; /* for now */
                        l2p_struct.l2p_devoffset = bn * devBlockSize;
                        l2p_struct.l2p_devoffset += fp->f_offset - offset;
                        error = copyout((caddr_t)&l2p_struct,
                                        (caddr_t)uap->arg,
                                        sizeof (l2p_struct));
                }
                return (error);


        default:
                return (EINVAL);
        }
        /* NOTREACHED */
}

/*
 * Common code for dup, dup2, and fcntl(F_DUPFD).
 */
int
finishdup(fdp, old, new, retval)
        register struct filedesc *fdp;
        register int old, new;
        register_t *retval;
{
        register struct file *fp;

        if ((fp = fdp->fd_ofiles[old]) == NULL ||
                        (fdp->fd_ofileflags[old] & UF_RESERVED)) {
                _fdrelse(fdp, new);
                return (EBADF);
        }
        fdp->fd_ofiles[new] = fp;
        fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE;
        (void)fref(fp);
        if (new > fdp->fd_lastfile)
                fdp->fd_lastfile = new;
        *retval = new;
        return (0);
}

/*
 * Close a file descriptor.
 */
struct close_args {
        int     fd;
};
/* ARGSUSED */
int
close(p, uap, retval)
        struct proc *p;
        struct close_args *uap;
        register_t *retval;
{
        int fd = uap->fd;
        register struct filedesc *fdp = p->p_fd;
        register struct file *fp;

        if ((u_int)fd >= fdp->fd_nfiles ||
                        (fp = fdp->fd_ofiles[fd]) == NULL ||
                        (fdp->fd_ofileflags[fd] & UF_RESERVED))
                return (EBADF);
        _fdrelse(fdp, fd);
        return (closef(fp, p));
}

/*
 * Return status information about a file descriptor.
 */
struct fstat_args {
        int     fd;
        struct  stat *sb;
};
/* ARGSUSED */
int
fstat(p, uap, retval)
        struct proc *p;
        register struct fstat_args *uap;
        register_t *retval;
{
        int fd = uap->fd;
        register struct filedesc *fdp = p->p_fd;
        register struct file *fp;
        struct stat ub;
        int error;

        if ((u_int)fd >= fdp->fd_nfiles ||
                        (fp = fdp->fd_ofiles[fd]) == NULL ||
                        (fdp->fd_ofileflags[fd] & UF_RESERVED))
                return (EBADF);
        switch (fp->f_type) {

        case DTYPE_VNODE:
                error = vn_stat((struct vnode *)fp->f_data, &ub, p);
                break;

        case DTYPE_SOCKET:
                error = soo_stat((struct socket *)fp->f_data, &ub);
                break;

        case DTYPE_PSXSHM:
                error = pshm_stat((void *)fp->f_data, &ub);
                break;
        default:
                panic("fstat");
                /*NOTREACHED*/
        }
        if (error == 0)
                error = copyout((caddr_t)&ub, (caddr_t)uap->sb,
                    sizeof (ub));
        return (error);
}

#if COMPAT_43
/*
 * Return status information about a file descriptor.
 */
struct ofstat_args {
        int     fd;
        struct  ostat *sb;
};
/* ARGSUSED */
ofstat(p, uap, retval)
        struct proc *p;
        register struct ofstat_args *uap;
        register_t *retval;
{
        int fd = uap->fd;
        register struct filedesc *fdp = p->p_fd;
        register struct file *fp;
        struct stat ub;
        struct ostat oub;
        int error;

        if ((u_int)fd >= fdp->fd_nfiles ||
                        (fp = fdp->fd_ofiles[fd]) == NULL ||
                        (fdp->fd_ofileflags[fd] & UF_RESERVED))
                return (EBADF);
        switch (fp->f_type) {

        case DTYPE_VNODE:
                error = vn_stat((struct vnode *)fp->f_data, &ub, p);
                break;

        case DTYPE_SOCKET:
                error = soo_stat((struct socket *)fp->f_data, &ub);
                break;

        default:
                panic("ofstat");
                /*NOTREACHED*/
        }
        cvtstat(&ub, &oub);
        if (error == 0)
                error = copyout((caddr_t)&oub, (caddr_t)uap->sb,
                    sizeof (oub));
        return (error);
}
#endif /* COMPAT_43 */

/*
 * Return pathconf information about a file descriptor.
 */
struct fpathconf_args {
        int     fd;
        int     name;
};
/* ARGSUSED */
fpathconf(p, uap, retval)
        struct proc *p;
        register struct fpathconf_args *uap;
        register_t *retval;
{
        int fd = uap->fd;
        struct filedesc *fdp = p->p_fd;
        struct file *fp;
        struct vnode *vp;

        if ((u_int)fd >= fdp->fd_nfiles ||
                        (fp = fdp->fd_ofiles[fd]) == NULL ||
                        (fdp->fd_ofileflags[fd] & UF_RESERVED))
                return (EBADF);
        switch (fp->f_type) {

        case DTYPE_SOCKET:
                if (uap->name != _PC_PIPE_BUF)
                        return (EINVAL);
                *retval = PIPE_BUF;
                return (0);

        case DTYPE_VNODE:
                vp = (struct vnode *)fp->f_data;
                return (VOP_PATHCONF(vp, uap->name, retval));

        default:
                panic("fpathconf");
        }
        /*NOTREACHED*/
}

/*
 * Allocate a file descriptor for the process.
 */
int fdexpand;

int
fdalloc(p, want, result)
        struct proc *p;
        int want;
        int *result;
{
        register struct filedesc *fdp = p->p_fd;
        register int i;
        int lim, last, nfiles, oldnfiles;
        struct file **newofiles, **ofiles;
        char *newofileflags, *ofileflags;

        /*
         * Search for a free descriptor starting at the higher
         * of want or fd_freefile.  If that fails, consider
         * expanding the ofile array.
         */
        lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles);
        for (;;) {
                last = min(fdp->fd_nfiles, lim);
                if ((i = want) < fdp->fd_freefile)
                        i = fdp->fd_freefile;
                ofiles = &fdp->fd_ofiles[i];
                ofileflags = &fdp->fd_ofileflags[i];
                for (; i < last; i++) {
                        if (*ofiles == NULL && !(*ofileflags & UF_RESERVED)) {
                                *ofileflags = UF_RESERVED;
                                if (i > fdp->fd_lastfile)
                                        fdp->fd_lastfile = i;
                                if (want <= fdp->fd_freefile)
                                        fdp->fd_freefile = i;
                                *result = i;
                                return (0);
                        }
                        ofiles++; ofileflags++;
                }

                /*
                 * No space in current array.  Expand?
                 */
                if (fdp->fd_nfiles >= lim)
                        return (EMFILE);
                if (fdp->fd_nfiles < NDEXTENT)
                        nfiles = NDEXTENT;
                else
                        nfiles = 2 * fdp->fd_nfiles;
                /* Enforce lim */
                if (nfiles > lim)
                        nfiles = lim;
                MALLOC_ZONE(newofiles, struct file **,
                                nfiles * OFILESIZE, M_OFILETABL, M_WAITOK);
                if (fdp->fd_nfiles >= nfiles) {
                        FREE_ZONE(newofiles, nfiles * OFILESIZE, M_OFILETABL);
                        continue;
                }
                newofileflags = (char *) &newofiles[nfiles];
                /*
                 * Copy the existing ofile and ofileflags arrays
                 * and zero the new portion of each array.
                 */
                oldnfiles = fdp->fd_nfiles;
                (void) memcpy(newofiles, fdp->fd_ofiles,
                                oldnfiles * sizeof *fdp->fd_ofiles);
                (void) memset(&newofiles[oldnfiles], 0,
                                (nfiles - oldnfiles) * sizeof *fdp->fd_ofiles);

                (void) memcpy(newofileflags, fdp->fd_ofileflags,
                                oldnfiles * sizeof *fdp->fd_ofileflags);
                (void) memset(&newofileflags[oldnfiles], 0,
                                (nfiles - oldnfiles) *
                                                sizeof *fdp->fd_ofileflags);
                ofiles = fdp->fd_ofiles;
                fdp->fd_ofiles = newofiles;
                fdp->fd_ofileflags = newofileflags;
                fdp->fd_nfiles = nfiles;
                FREE_ZONE(ofiles, oldnfiles * OFILESIZE, M_OFILETABL);
                fdexpand++;
        }
}

/*
 * Check to see whether n user file descriptors
 * are available to the process p.
 */
int
fdavail(p, n)
        struct proc *p;
        register int n;
{
        register struct filedesc *fdp = p->p_fd;
        register struct file **fpp;
        register char *flags;
        register int i, lim;

        lim = min((int)p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles);
        if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0)
                return (1);
        fpp = &fdp->fd_ofiles[fdp->fd_freefile];
        flags = &fdp->fd_ofileflags[fdp->fd_freefile];
        for (i = fdp->fd_nfiles - fdp->fd_freefile; --i >= 0; fpp++, flags++)
                if (*fpp == NULL && !(*flags & UF_RESERVED) && --n <= 0)
                        return (1);
        return (0);
}

void
fdrelse(p, fd)
        struct proc *p;
        int fd;
{
        _fdrelse(p->p_fd, fd);
}

int
fdgetf(p, fd, resultfp)
        register struct proc *p;
        register int fd;
        struct file **resultfp;
{
        register struct filedesc *fdp = p->p_fd;
        struct file *fp;

        if ((u_int)fd >= fdp->fd_nfiles ||
                        (fp = fdp->fd_ofiles[fd]) == NULL ||
                        (fdp->fd_ofileflags[fd] & UF_RESERVED))
                return (EBADF);

        if (resultfp)
                *resultfp = fp;
        return (0);
}

/*
 * Create a new open file structure and allocate
 * a file decriptor for the process that refers to it.
 */
int
falloc(p, resultfp, resultfd)
        register struct proc *p;
        struct file **resultfp;
        int *resultfd;
{
        register struct file *fp, *fq;
        int error, i;

        if (error = fdalloc(p, 0, &i))
                return (error);
        if (nfiles >= maxfiles) {
                tablefull("file");
                return (ENFILE);
        }
        /*
         * Allocate a new file descriptor.
         * If the process has file descriptor zero open, add to the list
         * of open files at that point, otherwise put it at the front of
         * the list of open files.
         */
        nfiles++;
        MALLOC_ZONE(fp, struct file *, sizeof(struct file), M_FILE, M_WAITOK);
        bzero(fp, sizeof(struct file));
        if (fq = p->p_fd->fd_ofiles[0]) {
                LIST_INSERT_AFTER(fq, fp, f_list);
        } else {
                LIST_INSERT_HEAD(&filehead, fp, f_list);
        }
        p->p_fd->fd_ofiles[i] = fp;
        fp->f_count = 1;
        fp->f_cred = p->p_ucred;
        crhold(fp->f_cred);
        if (resultfp)
                *resultfp = fp;
        if (resultfd)
                *resultfd = i;
        return (0);
}

/*
 * Free a file structure.
 */
void
ffree(fp)
        register struct file *fp;
{
        register struct file *fq;
        struct ucred *cred;

        LIST_REMOVE(fp, f_list);
        cred = fp->f_cred;
        if (cred != NOCRED) {
                fp->f_cred = NOCRED;
                crfree(cred);
        }
#if 1 || DIAGNOSTIC
        fp->f_count = 0;
#endif
        nfiles--;
        FREE_ZONE(fp, sizeof *fp, M_FILE);
}

void
fdexec(p)
        struct proc *p;
{
        register struct filedesc *fdp = p->p_fd;
        register int i = fdp->fd_lastfile;
        register struct file **fpp = &fdp->fd_ofiles[i];
        register char *flags = &fdp->fd_ofileflags[i];

        while (i >= 0) {
                if ((*flags & (UF_RESERVED|UF_EXCLOSE)) == UF_EXCLOSE) {
                        register struct file *fp = *fpp;

                        *fpp = NULL; *flags = 0;
                        if (i == fdp->fd_lastfile && i > 0)
                                fdp->fd_lastfile--;
                        closef(fp, p);
                }
                else
                        *flags &= ~UF_MAPPED;

                i--; fpp--; flags--;
        }
}

/*
 * Copy a filedesc structure.
 */
struct filedesc *
fdcopy(p)
        struct proc *p;
{
        register struct filedesc *newfdp, *fdp = p->p_fd;
        register int i;

        MALLOC_ZONE(newfdp, struct filedesc *,
                        sizeof *newfdp, M_FILEDESC, M_WAITOK);
        (void) memcpy(newfdp, fdp, sizeof *newfdp);
        VREF(newfdp->fd_cdir);
        if (newfdp->fd_rdir)
                VREF(newfdp->fd_rdir);
        newfdp->fd_refcnt = 1;

        /*
         * If the number of open files fits in the internal arrays
         * of the open file structure, use them, otherwise allocate
         * additional memory for the number of descriptors currently
         * in use.
         */
        if (newfdp->fd_lastfile < NDFILE)
                i = NDFILE;
        else {
                /*
                 * Compute the smallest multiple of NDEXTENT needed
                 * for the file descriptors currently in use,
                 * allowing the table to shrink.
                 */
                i = newfdp->fd_nfiles;
                while (i > 2 * NDEXTENT && i > newfdp->fd_lastfile * 2)
                        i /= 2;
        }
        MALLOC_ZONE(newfdp->fd_ofiles, struct file **,
                                i * OFILESIZE, M_OFILETABL, M_WAITOK);
        newfdp->fd_ofileflags = (char *) &newfdp->fd_ofiles[i];
        newfdp->fd_nfiles = i;
        if (fdp->fd_nfiles > 0) {
                register struct file **fpp;
                register char *flags;

                (void) memcpy(newfdp->fd_ofiles, fdp->fd_ofiles,
                                        i * sizeof *fdp->fd_ofiles);
                (void) memcpy(newfdp->fd_ofileflags, fdp->fd_ofileflags,
                                        i * sizeof *fdp->fd_ofileflags);

                fpp = newfdp->fd_ofiles;
                flags = newfdp->fd_ofileflags;
                for (i = newfdp->fd_lastfile; i-- >= 0; fpp++, flags++)
                        if (*fpp != NULL && !(*flags & UF_RESERVED)) {
                                (void)fref(*fpp);
                        } else {
                                *fpp = NULL;
                                *flags = 0;
                        }
        }
        else
                (void) memset(newfdp->fd_ofiles, 0, i * OFILESIZE);

        return (newfdp);
}

/*
 * Release a filedesc structure.
 */
void
fdfree(p)
        struct proc *p;
{
        register struct filedesc *fdp;
        register struct file **fpp;
        register int i;

        if ((fdp = p->p_fd) == NULL)
                return;
        if (--fdp->fd_refcnt > 0)
                return;
        p->p_fd = NULL;
        if (fdp->fd_nfiles > 0) {
                fpp = fdp->fd_ofiles;
                for (i = fdp->fd_lastfile; i-- >= 0; fpp++)
                        if (*fpp)
                                (void) closef(*fpp, p);
                FREE_ZONE(fdp->fd_ofiles,
                                fdp->fd_nfiles * OFILESIZE, M_OFILETABL);
        }
        vrele(fdp->fd_cdir);
        if (fdp->fd_rdir)
                vrele(fdp->fd_rdir);
        FREE_ZONE(fdp, sizeof *fdp, M_FILEDESC);
}

/*
 * Internal form of close.
 * Decrement reference count on file structure.
 * Note: p may be NULL when closing a file
 * that was being passed in a message.
 */
int
closef(fp, p)
        register struct file *fp;
        register struct proc *p;
{
        struct vnode *vp;
        struct flock lf;
        int error;

        if (fp == NULL)
                return (0);
        /*
         * POSIX record locking dictates that any close releases ALL
         * locks owned by this process.  This is handled by setting
         * a flag in the unlock to free ONLY locks obeying POSIX
         * semantics, and not to free BSD-style file locks.
         * If the descriptor was in a message, POSIX-style locks
         * aren't passed with the descriptor.
         */
        if (p && (p->p_flag & P_ADVLOCK) && fp->f_type == DTYPE_VNODE) {
                lf.l_whence = SEEK_SET;
                lf.l_start = 0;
                lf.l_len = 0;
                lf.l_type = F_UNLCK;
                vp = (struct vnode *)fp->f_data;
                (void) VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_POSIX);
        }
        if (frele(fp) > 0)
                return (0);
        if ((fp->f_flag & FHASLOCK) && fp->f_type == DTYPE_VNODE) {
                lf.l_whence = SEEK_SET;
                lf.l_start = 0;
                lf.l_len = 0;
                lf.l_type = F_UNLCK;
                vp = (struct vnode *)fp->f_data;
                (void) VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK);
        }
        if (fp->f_ops)
                error = (*fp->f_ops->fo_close)(fp, p);
        else
                error = 0;
        ffree(fp);
        return (error);
}

/*
 * Apply an advisory lock on a file descriptor.
 *
 * Just attempt to get a record lock of the requested type on
 * the entire file (l_whence = SEEK_SET, l_start = 0, l_len = 0).
 */
struct flock_args {
        int     fd;
        int     how;
};
/* ARGSUSED */
int
flock(p, uap, retval)
        struct proc *p;
        register struct flock_args *uap;
        register_t *retval;
{
        int fd = uap->fd;
        int how = uap->how;
        register struct filedesc *fdp = p->p_fd;
        register struct file *fp;
        struct vnode *vp;
        struct flock lf;

        if ((u_int)fd >= fdp->fd_nfiles ||
                        (fp = fdp->fd_ofiles[fd]) == NULL ||
                        (fdp->fd_ofileflags[fd] & UF_RESERVED))
                return (EBADF);
        if (fp->f_type != DTYPE_VNODE)
                return (EOPNOTSUPP);
        vp = (struct vnode *)fp->f_data;
        lf.l_whence = SEEK_SET;
        lf.l_start = 0;
        lf.l_len = 0;
        if (how & LOCK_UN) {
                lf.l_type = F_UNLCK;
                fp->f_flag &= ~FHASLOCK;
                return (VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK));
        }
        if (how & LOCK_EX)
                lf.l_type = F_WRLCK;
        else if (how & LOCK_SH)
                lf.l_type = F_RDLCK;
        else
                return (EBADF);
        fp->f_flag |= FHASLOCK;
        if (how & LOCK_NB)
                return (VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK));
        return (VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, F_FLOCK|F_WAIT));
}

/*
 * File Descriptor pseudo-device driver (/dev/fd/).
 *
 * Opening minor device N dup()s the file (if any) connected to file
 * descriptor N belonging to the calling process.  Note that this driver
 * consists of only the ``open()'' routine, because all subsequent
 * references to this file will be direct to the other driver.
 */
/* ARGSUSED */
int
fdopen(dev, mode, type, p)
        dev_t dev;
        int mode, type;
        struct proc *p;
{

        /*
         * XXX Kludge: set curproc->p_dupfd to contain the value of the
         * the file descriptor being sought for duplication. The error 
         * return ensures that the vnode for this device will be released
         * by vn_open. Open will detect this special error and take the
         * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN
         * will simply report the error.
         */
        p->p_dupfd = minor(dev);
        return (ENODEV);
}

/*
 * Duplicate the specified descriptor to a free descriptor.
 */
int
dupfdopen(fdp, indx, dfd, mode, error)
        register struct filedesc *fdp;
        register int indx, dfd;
        int mode;
        int error;
{
        register struct file *wfp;
        struct file *fp;

        /*
         * If the to-be-dup'd fd number is greater than the allowed number
         * of file descriptors, or the fd to be dup'd has already been
         * closed, reject.  Note, check for new == old is necessary as
         * falloc could allocate an already closed to-be-dup'd descriptor
         * as the new descriptor.
         */
        fp = fdp->fd_ofiles[indx];
        if ((u_int)dfd >= fdp->fd_nfiles ||
                        (wfp = fdp->fd_ofiles[dfd]) == NULL || wfp == fp ||
                        (fdp->fd_ofileflags[dfd] & UF_RESERVED))
                return (EBADF);

        /*
         * There are two cases of interest here.
         *
         * For ENODEV simply dup (dfd) to file descriptor
         * (indx) and return.
         *
         * For ENXIO steal away the file structure from (dfd) and
         * store it in (indx).  (dfd) is effectively closed by
         * this operation.
         *
         * Any other error code is just returned.
         */
        switch (error) {
        case ENODEV:
                /*
                 * Check that the mode the file is being opened for is a
                 * subset of the mode of the existing descriptor.
                 */
                if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag)
                        return (EACCES);
                (void)fref(wfp);
                if (indx > fdp->fd_lastfile)
                        fdp->fd_lastfile = indx;;
                fdp->fd_ofiles[indx] = wfp;
                fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
                return (0);

        case ENXIO:
                /*
                 * Steal away the file pointer from dfd, and stuff it into indx.
                 */
                if (indx > fdp->fd_lastfile)
                        fdp->fd_lastfile = indx;;
                fdp->fd_ofiles[indx] = fdp->fd_ofiles[dfd];
                fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
                _fdrelse(fdp, dfd);
                return (0);

        default:
                return (error);
        }
        /* NOTREACHED */
}

/* Reference manipulation routines for the file structure */

int
fref(struct file *fp)
{
        if (++fp->f_count <= 0)
                panic("fref: f_count");
        return ((int)fp->f_count);
}

int
frele(struct file *fp)
{
        if (--fp->f_count < 0)
                panic("frele: count < 0");
        return ((int)fp->f_count);
}

int
fcount(struct file *fp)
{
        return ((int)fp->f_count);
}