xnu-4903.221.2.tar.gz

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

/*
 * Copyright (c) 2000-2015 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The 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, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
/*
 * Copyright (c) 1982, 1986, 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. 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.
 *
 *      @(#)sys_generic.c       8.9 (Berkeley) 2/14/95
 */
/*
 * NOTICE: This file was modified by SPARTA, Inc. in 2006 to introduce
 * support for mandatory and extensible security protections.  This notice
 * is included in support of clause 2.2 (b) of the Apple Public License,
 * Version 2.0.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/filedesc.h>
#include <sys/ioctl.h>
#include <sys/file_internal.h>
#include <sys/proc_internal.h>
#include <sys/socketvar.h>
#include <sys/uio_internal.h>
#include <sys/kernel.h>
#include <sys/guarded.h>
#include <sys/stat.h>
#include <sys/malloc.h>
#include <sys/sysproto.h>

#include <sys/mount_internal.h>
#include <sys/protosw.h>
#include <sys/ev.h>
#include <sys/user.h>
#include <sys/kdebug.h>
#include <sys/poll.h>
#include <sys/event.h>
#include <sys/eventvar.h>
#include <sys/proc.h>
#include <sys/kauth.h>

#include <machine/smp.h>
#include <mach/mach_types.h>
#include <kern/kern_types.h>
#include <kern/assert.h>
#include <kern/kalloc.h>
#include <kern/thread.h>
#include <kern/clock.h>
#include <kern/ledger.h>
#include <kern/task.h>
#include <kern/telemetry.h>
#include <kern/waitq.h>
#include <kern/sched_prim.h>

#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/errno.h>
#include <sys/syscall.h>
#include <sys/pipe.h>

#include <security/audit/audit.h>

#include <net/if.h>
#include <net/route.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/ip_var.h>
#include <netinet/ip6.h>
#include <netinet/tcp.h>
#include <netinet/tcp_fsm.h>
#include <netinet/tcp_seq.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#include <netinet/tcpip.h>
#include <netinet/tcp_debug.h>
/* for wait queue based select */
#include <kern/waitq.h>
#include <kern/kalloc.h>
#include <sys/vnode_internal.h>

#if CONFIG_MACF
#include <security/mac_framework.h>
#endif

/* XXX should be in a header file somewhere */
void evsofree(struct socket *);
void evpipefree(struct pipe *);
void postpipeevent(struct pipe *, int);
void postevent(struct socket *, struct sockbuf *, int);
extern kern_return_t IOBSDGetPlatformUUID(__darwin_uuid_t uuid, mach_timespec_t timeoutp);

int rd_uio(struct proc *p, int fdes, uio_t uio, user_ssize_t *retval);
int wr_uio(struct proc *p, struct fileproc *fp, uio_t uio, user_ssize_t *retval);

__private_extern__ int  dofileread(vfs_context_t ctx, struct fileproc *fp,
                                                                   user_addr_t bufp, user_size_t nbyte, 
                                                                   off_t offset, int flags, user_ssize_t *retval);
__private_extern__ int  dofilewrite(vfs_context_t ctx, struct fileproc *fp,
                                                                        user_addr_t bufp, user_size_t nbyte, 
                                                                        off_t offset, int flags, user_ssize_t *retval);
__private_extern__ int  preparefileread(struct proc *p, struct fileproc **fp_ret, int fd, int check_for_vnode);
__private_extern__ void donefileread(struct proc *p, struct fileproc *fp_ret, int fd);

/* Conflict wait queue for when selects collide (opaque type) */
struct waitq select_conflict_queue;

/*
 * Init routine called from bsd_init.c
 */
void select_waitq_init(void);
void
select_waitq_init(void)
{
        waitq_init(&select_conflict_queue, SYNC_POLICY_FIFO);
}

#define f_flag f_fglob->fg_flag
#define f_type f_fglob->fg_ops->fo_type
#define f_msgcount f_fglob->fg_msgcount
#define f_cred f_fglob->fg_cred
#define f_ops f_fglob->fg_ops
#define f_offset f_fglob->fg_offset
#define f_data f_fglob->fg_data

/*
 * Read system call.
 *
 * Returns:     0                       Success
 *      preparefileread:EBADF
 *      preparefileread:ESPIPE
 *      preparefileread:ENXIO
 *      preparefileread:EBADF
 *      dofileread:???
 */
int
read(struct proc *p, struct read_args *uap, user_ssize_t *retval)
{
        __pthread_testcancel(1);
        return(read_nocancel(p, (struct read_nocancel_args *)uap, retval));
}

int
read_nocancel(struct proc *p, struct read_nocancel_args *uap, user_ssize_t *retval)
{
        struct fileproc *fp;
        int error;
        int fd = uap->fd;
        struct vfs_context context;

        if ( (error = preparefileread(p, &fp, fd, 0)) )
                return (error);

        context = *(vfs_context_current());
        context.vc_ucred = fp->f_fglob->fg_cred;

        error = dofileread(&context, fp, uap->cbuf, uap->nbyte,
                           (off_t)-1, 0, retval);

        donefileread(p, fp, fd);

        return (error);
}

/* 
 * Pread system call
 *
 * Returns:     0                       Success
 *      preparefileread:EBADF
 *      preparefileread:ESPIPE
 *      preparefileread:ENXIO
 *      preparefileread:EBADF
 *      dofileread:???
 */
int
pread(struct proc *p, struct pread_args *uap, user_ssize_t *retval)
{
        __pthread_testcancel(1);
        return(pread_nocancel(p, (struct pread_nocancel_args *)uap, retval));
}

int
pread_nocancel(struct proc *p, struct pread_nocancel_args *uap, user_ssize_t *retval)
{
        struct fileproc *fp = NULL;     /* fp set by preparefileread() */
        int fd = uap->fd;
        int error;
        struct vfs_context context;

        if ( (error = preparefileread(p, &fp, fd, 1)) )
                goto out;

        context = *(vfs_context_current());
        context.vc_ucred = fp->f_fglob->fg_cred;

        error = dofileread(&context, fp, uap->buf, uap->nbyte,
                        uap->offset, FOF_OFFSET, retval);
        
        donefileread(p, fp, fd);

        KERNEL_DEBUG_CONSTANT((BSDDBG_CODE(DBG_BSD_SC_EXTENDED_INFO, SYS_pread) | DBG_FUNC_NONE),
              uap->fd, uap->nbyte, (unsigned int)((uap->offset >> 32)), (unsigned int)(uap->offset), 0);

out:
        return (error);
}

/*
 * Code common for read and pread
 */

void
donefileread(struct proc *p, struct fileproc *fp, int fd)
{
        proc_fdlock_spin(p);
        fp_drop(p, fd, fp, 1);
        proc_fdunlock(p);
}

/*
 * Returns:     0                       Success
 *              EBADF
 *              ESPIPE
 *              ENXIO
 *      fp_lookup:EBADF
 *      fo_read:???
 */
int
preparefileread(struct proc *p, struct fileproc **fp_ret, int fd, int check_for_pread)
{
        vnode_t vp;
        int     error;
        struct fileproc *fp;

        AUDIT_ARG(fd, fd);

        proc_fdlock_spin(p);

        error = fp_lookup(p, fd, &fp, 1);

        if (error) {
                proc_fdunlock(p);
                return (error);
        }
        if ((fp->f_flag & FREAD) == 0) {
                error = EBADF;
                goto out;
        }
        if (check_for_pread && (fp->f_type != DTYPE_VNODE)) {
                error = ESPIPE;
                goto out;
        }
        if (fp->f_type == DTYPE_VNODE) {
                vp = (struct vnode *)fp->f_fglob->fg_data;

                if (check_for_pread && (vnode_isfifo(vp))) {
                        error = ESPIPE;
                        goto out;
                } 
                if (check_for_pread && (vp->v_flag & VISTTY)) {
                        error = ENXIO;
                        goto out;
                }
        }

        *fp_ret = fp;

        proc_fdunlock(p);
        return (0);

out:
        fp_drop(p, fd, fp, 1);
        proc_fdunlock(p);
        return (error);
}


/*
 * Returns:     0                       Success
 *              EINVAL
 *      fo_read:???
 */
__private_extern__ int
dofileread(vfs_context_t ctx, struct fileproc *fp,
           user_addr_t bufp, user_size_t nbyte, off_t offset, int flags,
           user_ssize_t *retval)
{
        uio_t auio;
        user_ssize_t bytecnt;
        long error = 0;
        char uio_buf[ UIO_SIZEOF(1) ];

        if (nbyte > INT_MAX)
                return (EINVAL);

        if (IS_64BIT_PROCESS(vfs_context_proc(ctx))) {
                auio = uio_createwithbuffer(1, offset, UIO_USERSPACE64, UIO_READ, 
                                                                          &uio_buf[0], sizeof(uio_buf));
        } else {
                auio = uio_createwithbuffer(1, offset, UIO_USERSPACE32, UIO_READ, 
                                                                          &uio_buf[0], sizeof(uio_buf));
        }
        uio_addiov(auio, bufp, nbyte);

        bytecnt = nbyte;

        if ((error = fo_read(fp, auio, flags, ctx))) {
                if (uio_resid(auio) != bytecnt && (error == ERESTART ||
                        error == EINTR || error == EWOULDBLOCK))
                        error = 0;
        }
        bytecnt -= uio_resid(auio);

        *retval = bytecnt;

        return (error);
}

/*      
 * Scatter read system call.
 *
 * Returns:     0                       Success
 *              EINVAL
 *              ENOMEM
 *      copyin:EFAULT
 *      rd_uio:???
 */
int
readv(struct proc *p, struct readv_args *uap, user_ssize_t *retval)
{
        __pthread_testcancel(1);
        return(readv_nocancel(p, (struct readv_nocancel_args *)uap, retval));
}

int
readv_nocancel(struct proc *p, struct readv_nocancel_args *uap, user_ssize_t *retval)
{
        uio_t auio = NULL;
        int error;
        struct user_iovec *iovp;

        /* Verify range bedfore calling uio_create() */
        if (uap->iovcnt <= 0 || uap->iovcnt > UIO_MAXIOV)
                return (EINVAL);

        /* allocate a uio large enough to hold the number of iovecs passed */
        auio = uio_create(uap->iovcnt, 0,
                                  (IS_64BIT_PROCESS(p) ? UIO_USERSPACE64 : UIO_USERSPACE32),
                                  UIO_READ);
                                  
        /* get location of iovecs within the uio.  then copyin the iovecs from
         * user space.
         */
        iovp = uio_iovsaddr(auio);
        if (iovp == NULL) {
                error = ENOMEM;
                goto ExitThisRoutine;
        }
        error = copyin_user_iovec_array(uap->iovp,
                IS_64BIT_PROCESS(p) ? UIO_USERSPACE64 : UIO_USERSPACE32,
                uap->iovcnt, iovp);
        if (error) {
                goto ExitThisRoutine;
        }
        
        /* finalize uio_t for use and do the IO 
         */
        error = uio_calculateresid(auio);
        if (error) {
                goto ExitThisRoutine;
        }
        error = rd_uio(p, uap->fd, auio, retval);

ExitThisRoutine:
        if (auio != NULL) {
                uio_free(auio);
        }
        return (error);
}

/*
 * Write system call
 *
 * Returns:     0                       Success
 *              EBADF
 *      fp_lookup:EBADF
 *      dofilewrite:???
 */
int
write(struct proc *p, struct write_args *uap, user_ssize_t *retval)
{
        __pthread_testcancel(1);
        return(write_nocancel(p, (struct write_nocancel_args *)uap, retval));

}

int
write_nocancel(struct proc *p, struct write_nocancel_args *uap, user_ssize_t *retval)
{
        struct fileproc *fp;
        int error;      
        int fd = uap->fd;
        bool wrote_some = false;

        AUDIT_ARG(fd, fd);

        error = fp_lookup(p,fd,&fp,0);
        if (error)
                return(error);
        if ((fp->f_flag & FWRITE) == 0) {
                error = EBADF;
        } else if (FP_ISGUARDED(fp, GUARD_WRITE)) {
                proc_fdlock(p);
                error = fp_guard_exception(p, fd, fp, kGUARD_EXC_WRITE);
                proc_fdunlock(p);
        } else {
                struct vfs_context context = *(vfs_context_current());
                context.vc_ucred = fp->f_fglob->fg_cred;

                error = dofilewrite(&context, fp, uap->cbuf, uap->nbyte,
                        (off_t)-1, 0, retval);

                wrote_some = *retval > 0;
        }
        if (wrote_some)
                fp_drop_written(p, fd, fp);
        else
                fp_drop(p, fd, fp, 0);
        return(error);  
}

/*                          
 * pwrite system call
 *
 * Returns:     0                       Success
 *              EBADF
 *              ESPIPE
 *              ENXIO
 *              EINVAL
 *      fp_lookup:EBADF
 *      dofilewrite:???
 */
int
pwrite(struct proc *p, struct pwrite_args *uap, user_ssize_t *retval)
{
        __pthread_testcancel(1);
        return(pwrite_nocancel(p, (struct pwrite_nocancel_args *)uap, retval));
}

int
pwrite_nocancel(struct proc *p, struct pwrite_nocancel_args *uap, user_ssize_t *retval)
{
        struct fileproc *fp;
        int error; 
        int fd = uap->fd;
        vnode_t vp  = (vnode_t)0;
        bool wrote_some = false;

        AUDIT_ARG(fd, fd);

        error = fp_lookup(p,fd,&fp,0);
        if (error)
                return(error);

        if ((fp->f_flag & FWRITE) == 0) {
                error = EBADF;
        } else if (FP_ISGUARDED(fp, GUARD_WRITE)) {
                proc_fdlock(p);
                error = fp_guard_exception(p, fd, fp, kGUARD_EXC_WRITE);
                proc_fdunlock(p);
        } else {
                struct vfs_context context = *vfs_context_current();
                context.vc_ucred = fp->f_fglob->fg_cred;

                if (fp->f_type != DTYPE_VNODE) {
                        error = ESPIPE;
                        goto errout;
                }
                vp = (vnode_t)fp->f_fglob->fg_data;
                if (vnode_isfifo(vp)) {
                        error = ESPIPE;
                        goto errout;
                } 
                if ((vp->v_flag & VISTTY)) {
                        error = ENXIO;
                        goto errout;
                }
                if (uap->offset == (off_t)-1) {
                        error = EINVAL;
                        goto errout;
                }

                    error = dofilewrite(&context, fp, uap->buf, uap->nbyte,
                        uap->offset, FOF_OFFSET, retval);
                        wrote_some = *retval > 0;
        }
errout:
        if (wrote_some)
                fp_drop_written(p, fd, fp);
        else
                fp_drop(p, fd, fp, 0);

        KERNEL_DEBUG_CONSTANT((BSDDBG_CODE(DBG_BSD_SC_EXTENDED_INFO, SYS_pwrite) | DBG_FUNC_NONE),
              uap->fd, uap->nbyte, (unsigned int)((uap->offset >> 32)), (unsigned int)(uap->offset), 0);
        
        return(error);
}

/*
 * Returns:     0                       Success
 *              EINVAL
 *      <fo_write>:EPIPE
 *      <fo_write>:???                  [indirect through struct fileops]
 */
__private_extern__ int                  
dofilewrite(vfs_context_t ctx, struct fileproc *fp,
            user_addr_t bufp, user_size_t nbyte, off_t offset, int flags,
            user_ssize_t *retval)
{       
        uio_t auio;
        long error = 0;
        user_ssize_t bytecnt;
        char uio_buf[ UIO_SIZEOF(1) ];

        if (nbyte > INT_MAX) {
                *retval = 0;
                return (EINVAL);
        }

        if (IS_64BIT_PROCESS(vfs_context_proc(ctx))) {
                auio = uio_createwithbuffer(1, offset, UIO_USERSPACE64, UIO_WRITE, 
                                                                          &uio_buf[0], sizeof(uio_buf));
        } else {
                auio = uio_createwithbuffer(1, offset, UIO_USERSPACE32, UIO_WRITE, 
                                                                          &uio_buf[0], sizeof(uio_buf));
        }
        uio_addiov(auio, bufp, nbyte);

        bytecnt = nbyte; 
        if ((error = fo_write(fp, auio, flags, ctx))) {
                if (uio_resid(auio) != bytecnt && (error == ERESTART ||
                        error == EINTR || error == EWOULDBLOCK))
                        error = 0;
                /* The socket layer handles SIGPIPE */
                if (error == EPIPE && fp->f_type != DTYPE_SOCKET &&
                    (fp->f_fglob->fg_lflags & FG_NOSIGPIPE) == 0) {
                        /* XXX Raise the signal on the thread? */
                        psignal(vfs_context_proc(ctx), SIGPIPE);
                }
        }
        bytecnt -= uio_resid(auio);
        *retval = bytecnt;

        return (error); 
}
        
/*      
 * Gather write system call  
 */     
int
writev(struct proc *p, struct writev_args *uap, user_ssize_t *retval)
{
        __pthread_testcancel(1);
        return(writev_nocancel(p, (struct writev_nocancel_args *)uap, retval));
}

int
writev_nocancel(struct proc *p, struct writev_nocancel_args *uap, user_ssize_t *retval)
{
        uio_t auio = NULL;
        int error;
        struct fileproc *fp;
        struct user_iovec *iovp;
        bool wrote_some = false;

        AUDIT_ARG(fd, uap->fd);

        /* Verify range bedfore calling uio_create() */
        if (uap->iovcnt <= 0 || uap->iovcnt > UIO_MAXIOV)
                return (EINVAL);

        /* allocate a uio large enough to hold the number of iovecs passed */
        auio = uio_create(uap->iovcnt, 0,
                                  (IS_64BIT_PROCESS(p) ? UIO_USERSPACE64 : UIO_USERSPACE32),
                                  UIO_WRITE);
                                  
        /* get location of iovecs within the uio.  then copyin the iovecs from
         * user space.
         */
        iovp = uio_iovsaddr(auio);
        if (iovp == NULL) {
                error = ENOMEM;
                goto ExitThisRoutine;
        }
        error = copyin_user_iovec_array(uap->iovp,
                IS_64BIT_PROCESS(p) ? UIO_USERSPACE64 : UIO_USERSPACE32,
                uap->iovcnt, iovp);
        if (error) {
                goto ExitThisRoutine;
        }
        
        /* finalize uio_t for use and do the IO 
         */
        error = uio_calculateresid(auio);
        if (error) {
                goto ExitThisRoutine;
        }

        error = fp_lookup(p, uap->fd, &fp, 0);
        if (error)
                goto ExitThisRoutine;
        
        if ((fp->f_flag & FWRITE) == 0) {
                error = EBADF;
        } else if (FP_ISGUARDED(fp, GUARD_WRITE)) {
                proc_fdlock(p);
                error = fp_guard_exception(p, uap->fd, fp, kGUARD_EXC_WRITE);
                proc_fdunlock(p);
        } else {
                error = wr_uio(p, fp, auio, retval);
                wrote_some = *retval > 0;
        }
        
        if (wrote_some)
                fp_drop_written(p, uap->fd, fp);
        else
                fp_drop(p, uap->fd, fp, 0);

ExitThisRoutine:
        if (auio != NULL) {
                uio_free(auio);
        }
        return (error);
}


int
wr_uio(struct proc *p, struct fileproc *fp, uio_t uio, user_ssize_t *retval)
{
        int error;
        user_ssize_t count;
        struct vfs_context context = *vfs_context_current();

        count = uio_resid(uio);

        context.vc_ucred = fp->f_cred;
        error = fo_write(fp, uio, 0, &context);
        if (error) {
                if (uio_resid(uio) != count && (error == ERESTART ||
                                                error == EINTR || error == EWOULDBLOCK))
                        error = 0;
                /* The socket layer handles SIGPIPE */
                if (error == EPIPE && fp->f_type != DTYPE_SOCKET &&
                    (fp->f_fglob->fg_lflags & FG_NOSIGPIPE) == 0)
                        psignal(p, SIGPIPE);
        }
        *retval = count - uio_resid(uio);

        return(error);
}


int
rd_uio(struct proc *p, int fdes, uio_t uio, user_ssize_t *retval)
{
        struct fileproc *fp;
        int error;
        user_ssize_t count;
        struct vfs_context context = *vfs_context_current();

        if ( (error = preparefileread(p, &fp, fdes, 0)) )
                return (error);

        count = uio_resid(uio);

        context.vc_ucred = fp->f_cred;

        error = fo_read(fp, uio, 0, &context);

        if (error) {
                if (uio_resid(uio) != count && (error == ERESTART ||
                                                error == EINTR || error == EWOULDBLOCK))
                        error = 0;
        }
        *retval = count - uio_resid(uio);

        donefileread(p, fp, fdes);

        return (error);
}

/*
 * Ioctl system call
 *
 * Returns:     0                       Success
 *              EBADF
 *              ENOTTY
 *              ENOMEM
 *              ESRCH
 *      copyin:EFAULT
 *      copyoutEFAULT
 *      fp_lookup:EBADF                 Bad file descriptor
 *      fo_ioctl:???
 */
int
ioctl(struct proc *p, struct ioctl_args *uap, __unused int32_t *retval)
{
        struct fileproc *fp = NULL;
        int error = 0;
        u_int size = 0;
        caddr_t datap = NULL, memp = NULL;
        boolean_t is64bit = FALSE;
        int tmp = 0;
#define STK_PARAMS      128
        char stkbuf[STK_PARAMS] = {};
        int fd = uap->fd;
        u_long com = uap->com;
        struct vfs_context context = *vfs_context_current();

        AUDIT_ARG(fd, uap->fd);
        AUDIT_ARG(addr, uap->data);

        is64bit = proc_is64bit(p);
#if CONFIG_AUDIT
        if (is64bit)
                AUDIT_ARG(value64, com);
        else
                AUDIT_ARG(cmd, CAST_DOWN_EXPLICIT(int, com));
#endif /* CONFIG_AUDIT */

        /*
         * Interpret high order word to find amount of data to be
         * copied to/from the user's address space.
         */
        size = IOCPARM_LEN(com);
        if (size > IOCPARM_MAX)
                        return ENOTTY;
        if (size > sizeof (stkbuf)) {
                if ((memp = (caddr_t)kalloc(size)) == 0)
                        return ENOMEM;
                datap = memp;
        } else
                datap = &stkbuf[0];
        if (com & IOC_IN) {
                if (size) {
                        error = copyin(uap->data, datap, size);
                        if (error)
                                goto out_nofp;
                } else {
                        /* XXX - IOC_IN and no size?  we should proably return an error here!! */
                        if (is64bit) {
                                *(user_addr_t *)datap = uap->data;
                        }
                        else {
                                *(uint32_t *)datap = (uint32_t)uap->data;
                        }
                }
        } else if ((com & IOC_OUT) && size)
                /*
                 * Zero the buffer so the user always
                 * gets back something deterministic.
                 */
                bzero(datap, size);
        else if (com & IOC_VOID) {
                /* XXX - this is odd since IOC_VOID means no parameters */
                if (is64bit) {
                        *(user_addr_t *)datap = uap->data;
                }
                else {
                        *(uint32_t *)datap = (uint32_t)uap->data;
                }
        }

        proc_fdlock(p);
        error = fp_lookup(p,fd,&fp,1);
        if (error)  {
                proc_fdunlock(p);
                goto out_nofp;
        }

        AUDIT_ARG(file, p, fp);

        if ((fp->f_flag & (FREAD | FWRITE)) == 0) {
                        error = EBADF;
                        goto out;
        }

        context.vc_ucred = fp->f_fglob->fg_cred;

#if CONFIG_MACF
        error = mac_file_check_ioctl(context.vc_ucred, fp->f_fglob, com);
        if (error)
                goto out;
#endif

        switch (com) {
        case FIONCLEX:
                *fdflags(p, fd) &= ~UF_EXCLOSE;
                break;

        case FIOCLEX:
                *fdflags(p, fd) |= UF_EXCLOSE;
                break;

        case FIONBIO:
                if ( (tmp = *(int *)datap) )
                        fp->f_flag |= FNONBLOCK;
                else
                        fp->f_flag &= ~FNONBLOCK;
                error = fo_ioctl(fp, FIONBIO, (caddr_t)&tmp, &context);
                break;

        case FIOASYNC:
                if ( (tmp = *(int *)datap) )
                        fp->f_flag |= FASYNC;
                else
                        fp->f_flag &= ~FASYNC;
                error = fo_ioctl(fp, FIOASYNC, (caddr_t)&tmp, &context);
                break;

        case FIOSETOWN:
                tmp = *(int *)datap;
                if (fp->f_type == DTYPE_SOCKET) {
                        ((struct socket *)fp->f_data)->so_pgid = tmp;
                        break;
                }
                if (fp->f_type == DTYPE_PIPE) {
                        error = fo_ioctl(fp, (int)TIOCSPGRP, (caddr_t)&tmp, &context);
                        break;
                }
                if (tmp <= 0) {
                        tmp = -tmp;
                } else {
                        struct proc *p1 = proc_find(tmp);
                        if (p1 == 0) {
                                error = ESRCH;
                                break;
                        }
                        tmp = p1->p_pgrpid;
                        proc_rele(p1);
                }
                error = fo_ioctl(fp, (int)TIOCSPGRP, (caddr_t)&tmp, &context);
                break;

        case FIOGETOWN:
                if (fp->f_type == DTYPE_SOCKET) {
                        *(int *)datap = ((struct socket *)fp->f_data)->so_pgid;
                        break;
                }
                error = fo_ioctl(fp, TIOCGPGRP, datap, &context);
                *(int *)datap = -*(int *)datap;
                break;

        default:
                error = fo_ioctl(fp, com, datap, &context);
                /*
                 * Copy any data to user, size was
                 * already set and checked above.
                 */
                if (error == 0 && (com & IOC_OUT) && size)
                        error = copyout(datap, uap->data, (u_int)size);
                break;
        }
out:
        fp_drop(p, fd, fp, 1);
        proc_fdunlock(p);

out_nofp:
        if (memp)
                kfree(memp, size);
        return(error);
}

int     selwait, nselcoll;
#define SEL_FIRSTPASS 1
#define SEL_SECONDPASS 2
extern int selcontinue(int error);
extern int selprocess(int error, int sel_pass);
static int selscan(struct proc *p, struct _select * sel, struct _select_data * seldata,
                        int nfd, int32_t *retval, int sel_pass, struct waitq_set *wqset);
static int selcount(struct proc *p, u_int32_t *ibits, int nfd, int *count);
static int seldrop_locked(struct proc *p, u_int32_t *ibits, int nfd, int lim, int *need_wakeup, int fromselcount);
static int seldrop(struct proc *p, u_int32_t *ibits, int nfd);
static int select_internal(struct proc *p, struct select_nocancel_args *uap, uint64_t timeout, int32_t *retval);

/*
 * Select system call.
 *
 * Returns:     0                       Success
 *              EINVAL                  Invalid argument
 *              EAGAIN                  Nonconformant error if allocation fails
 */
int
select(struct proc *p, struct select_args *uap, int32_t *retval)
{
        __pthread_testcancel(1);
        return select_nocancel(p, (struct select_nocancel_args *)uap, retval);
}

int
select_nocancel(struct proc *p, struct select_nocancel_args *uap, int32_t *retval)
{
        uint64_t timeout = 0;

        if (uap->tv) {
                int err;
                struct timeval atv;
                if (IS_64BIT_PROCESS(p)) {
                        struct user64_timeval atv64;
                        err = copyin(uap->tv, (caddr_t)&atv64, sizeof(atv64));
                        /* Loses resolution - assume timeout < 68 years */
                        atv.tv_sec = atv64.tv_sec;
                        atv.tv_usec = atv64.tv_usec;
                } else {
                        struct user32_timeval atv32;
                        err = copyin(uap->tv, (caddr_t)&atv32, sizeof(atv32));
                        atv.tv_sec = atv32.tv_sec;
                        atv.tv_usec = atv32.tv_usec;
                }
                if (err)
                        return err;

                if (itimerfix(&atv)) {
                        err = EINVAL;
                        return err;
                }

                clock_absolutetime_interval_to_deadline(tvtoabstime(&atv), &timeout);
        }

        return select_internal(p, uap, timeout, retval);
}

int
pselect(struct proc *p, struct pselect_args *uap, int32_t *retval)
{
        __pthread_testcancel(1);
        return pselect_nocancel(p, (struct pselect_nocancel_args *)uap, retval);
}

int
pselect_nocancel(struct proc *p, struct pselect_nocancel_args *uap, int32_t *retval)
{
        int err;
        struct uthread *ut;
        uint64_t timeout = 0;

        if (uap->ts) {
                struct timespec ts;

                if (IS_64BIT_PROCESS(p)) {
                        struct user64_timespec ts64;
                        err = copyin(uap->ts, (caddr_t)&ts64, sizeof(ts64));
                        ts.tv_sec = ts64.tv_sec;
                        ts.tv_nsec = ts64.tv_nsec;
                } else {
                        struct user32_timespec ts32;
                        err = copyin(uap->ts, (caddr_t)&ts32, sizeof(ts32));
                        ts.tv_sec = ts32.tv_sec;
                        ts.tv_nsec = ts32.tv_nsec;
                }
                if (err) {
                        return err;
                }

                if (!timespec_is_valid(&ts)) {
                        return EINVAL;
                }
                clock_absolutetime_interval_to_deadline(tstoabstime(&ts), &timeout);
        }

        ut = get_bsdthread_info(current_thread());

        if (uap->mask != USER_ADDR_NULL) {
                /* save current mask, then copyin and set new mask */
                sigset_t newset;
                err = copyin(uap->mask, &newset, sizeof(sigset_t));
                if (err) {
                        return err;
                }
                ut->uu_oldmask = ut->uu_sigmask;
                ut->uu_flag |= UT_SAS_OLDMASK;
                ut->uu_sigmask = (newset & ~sigcantmask);
        }

        err = select_internal(p, (struct select_nocancel_args *)uap, timeout, retval);

        if (err != EINTR && ut->uu_flag & UT_SAS_OLDMASK) {
                /*
                 * Restore old mask (direct return case). NOTE: EINTR can also be returned
                 * if the thread is cancelled. In that case, we don't reset the signal
                 * mask to its original value (which usually happens in the signal
                 * delivery path). This behavior is permitted by POSIX.
                 */
                ut->uu_sigmask = ut->uu_oldmask;
                ut->uu_oldmask = 0;
                ut->uu_flag &= ~UT_SAS_OLDMASK;
        }

        return err;
}

/*
 * Generic implementation of {,p}select. Care: we type-pun uap across the two
 * syscalls, which differ slightly. The first 4 arguments (nfds and the fd sets)
 * are identical. The 5th (timeout) argument points to different types, so we
 * unpack in the syscall-specific code, but the generic code still does a null
 * check on this argument to determine if a timeout was specified.
 */
static int
select_internal(struct proc *p, struct select_nocancel_args *uap, uint64_t timeout, int32_t *retval)
{
        int error = 0;
        u_int ni, nw;
        thread_t th_act;
        struct uthread  *uth;
        struct _select *sel;
        struct _select_data *seldata;
        int needzerofill = 1;
        int count = 0;
        size_t sz = 0;

        th_act = current_thread();
        uth = get_bsdthread_info(th_act);
        sel = &uth->uu_select;
        seldata = &uth->uu_save.uus_select_data;
        *retval = 0;

        seldata->args = uap;
        seldata->retval = retval;
        seldata->wqp = NULL;
        seldata->count = 0;

        if (uap->nd < 0) {
                return (EINVAL);
        }

        /* select on thread of process that already called proc_exit() */
        if (p->p_fd == NULL) {
                return (EBADF);
        }

        if (uap->nd > p->p_fd->fd_nfiles)
                uap->nd = p->p_fd->fd_nfiles; /* forgiving; slightly wrong */

        nw = howmany(uap->nd, NFDBITS);
        ni = nw * sizeof(fd_mask);

        /*
         * if the previously allocated space for the bits is smaller than
         * what is requested or no space has yet been allocated for this
         * thread, allocate enough space now.
         *
         * Note: If this process fails, select() will return EAGAIN; this
         * is the same thing pool() returns in a no-memory situation, but
         * it is not a POSIX compliant error code for select().
         */
        if (sel->nbytes < (3 * ni)) {
                int nbytes = 3 * ni;

                /* Free previous allocation, if any */
                if (sel->ibits != NULL)
                        FREE(sel->ibits, M_TEMP);
                if (sel->obits != NULL) {
                        FREE(sel->obits, M_TEMP);
                        /* NULL out; subsequent ibits allocation may fail */
                        sel->obits = NULL;
                }

                MALLOC(sel->ibits, u_int32_t *, nbytes, M_TEMP, M_WAITOK | M_ZERO);
                if (sel->ibits == NULL)
                        return (EAGAIN);
                MALLOC(sel->obits, u_int32_t *, nbytes, M_TEMP, M_WAITOK | M_ZERO);
                if (sel->obits == NULL) {
                        FREE(sel->ibits, M_TEMP);
                        sel->ibits = NULL;
                        return (EAGAIN);
                }
                sel->nbytes = nbytes;
                needzerofill = 0;
        }

        if (needzerofill) {
                bzero((caddr_t)sel->ibits, sel->nbytes);
                bzero((caddr_t)sel->obits, sel->nbytes);
        }

        /*
         * get the bits from the user address space
         */
#define getbits(name, x) \
        do { \
                if (uap->name && (error = copyin(uap->name, \
                        (caddr_t)&sel->ibits[(x) * nw], ni))) \
                        goto continuation; \
        } while (0)

        getbits(in, 0);
        getbits(ou, 1);
        getbits(ex, 2);
#undef  getbits

        seldata->abstime = timeout;

        if ( (error = selcount(p, sel->ibits, uap->nd, &count)) ) {
                        goto continuation;
        }

        /*
         * We need an array of waitq pointers. This is due to the new way
         * in which waitqs are linked to sets. When a thread selects on a
         * file descriptor, a waitq (embedded in a selinfo structure) is
         * added to the thread's local waitq set. There is no longer any
         * way to directly iterate over all members of a given waitq set.
         * The process of linking a waitq into a set may allocate a link
         * table object. Because we can't iterate over all the waitqs to
         * which our thread waitq set belongs, we need a way of removing
         * this link object!
         *
         * Thus we need a buffer which will hold one waitq pointer
         * per FD being selected. During the tear-down phase we can use
         * these pointers to dis-associate the underlying selinfo's waitq
         * from our thread's waitq set.
         *
         * Because we also need to allocate a waitq set for this thread,
         * we use a bare buffer pointer to hold all the memory. Note that
         * this memory is cached in the thread pointer and not reaped until
         * the thread exists. This is generally OK because threads that
         * call select tend to keep calling select repeatedly.
         */
        sz = ALIGN(sizeof(struct waitq_set)) + (count * sizeof(uint64_t));
        if (sz > uth->uu_wqstate_sz) {
                /* (re)allocate a buffer to hold waitq pointers */
                if (uth->uu_wqset) {
                        if (waitq_set_is_valid(uth->uu_wqset))
                                waitq_set_deinit(uth->uu_wqset);
                        FREE(uth->uu_wqset, M_SELECT);
                } else if (uth->uu_wqstate_sz && !uth->uu_wqset)
                        panic("select: thread structure corrupt! "
                              "uu_wqstate_sz:%ld, wqstate_buf == NULL",
                              uth->uu_wqstate_sz);
                uth->uu_wqstate_sz = sz;
                MALLOC(uth->uu_wqset, struct waitq_set *, sz, M_SELECT, M_WAITOK);
                if (!uth->uu_wqset)
                        panic("can't allocate %ld bytes for wqstate buffer",
                              uth->uu_wqstate_sz);
                waitq_set_init(uth->uu_wqset,
                               SYNC_POLICY_FIFO|SYNC_POLICY_PREPOST, NULL, NULL);
        }

        if (!waitq_set_is_valid(uth->uu_wqset))
                waitq_set_init(uth->uu_wqset,
                               SYNC_POLICY_FIFO|SYNC_POLICY_PREPOST, NULL, NULL);

        /* the last chunk of our buffer is an array of waitq pointers */
        seldata->wqp = (uint64_t *)((char *)(uth->uu_wqset) + ALIGN(sizeof(struct waitq_set)));
        bzero(seldata->wqp, sz - ALIGN(sizeof(struct waitq_set)));

        seldata->count = count;

continuation:

        if (error) {
                /*
                 * We have already cleaned up any state we established,
                 * either locally or as a result of selcount().  We don't
                 * need to wait_subqueue_unlink_all(), since we haven't set
                 * anything at this point.
                 */
                return (error);
        }

        return selprocess(0, SEL_FIRSTPASS);
}

int
selcontinue(int error)
{
        return selprocess(error, SEL_SECONDPASS);
}


/*
 * selprocess
 *
 * Parameters:  error                   The error code from our caller
 *              sel_pass                The pass we are on
 */
int
selprocess(int error, int sel_pass)
{
        int ncoll;
        u_int ni, nw;
        thread_t th_act;
        struct uthread  *uth;
        struct proc *p;
        struct select_nocancel_args *uap;
        int *retval;
        struct _select *sel;
        struct _select_data *seldata;
        int unwind = 1;
        int prepost = 0;
        int somewakeup = 0;
        int doretry = 0;
        wait_result_t wait_result;

        p = current_proc();
        th_act = current_thread();
        uth = get_bsdthread_info(th_act);
        sel = &uth->uu_select;
        seldata = &uth->uu_save.uus_select_data;
        uap = seldata->args;
        retval = seldata->retval;

        if ((error != 0) && (sel_pass == SEL_FIRSTPASS))
                unwind = 0;
        if (seldata->count == 0)
                unwind = 0;
retry:
        if (error != 0)
                goto done;

        ncoll = nselcoll;
        OSBitOrAtomic(P_SELECT, &p->p_flag);

        /* skip scans if the select is just for timeouts */
        if (seldata->count) {
                error = selscan(p, sel, seldata, uap->nd, retval, sel_pass, uth->uu_wqset);
                if (error || *retval) {
                        goto done;
                }
                if (prepost || somewakeup) {
                        /*
                         * if the select of log, then we can wakeup and
                         * discover some one else already read the data;
                         * go to select again if time permits
                         */
                        prepost = 0;
                        somewakeup = 0;
                        doretry = 1;
                }
        }

        if (uap->tv) {
                uint64_t        now;

                clock_get_uptime(&now);
                if (now >= seldata->abstime)
                        goto done;
        }

        if (doretry) {
                /* cleanup obits and try again */
                doretry = 0;
                sel_pass = SEL_FIRSTPASS;
                goto retry;
        }

        /*
         * To effect a poll, the timeout argument should be
         * non-nil, pointing to a zero-valued timeval structure.
         */
        if (uap->tv && seldata->abstime == 0) {
                goto done;
        }

        /* No spurious wakeups due to colls,no need to check for them */
         if ((sel_pass == SEL_SECONDPASS) || ((p->p_flag & P_SELECT) == 0)) {
                sel_pass = SEL_FIRSTPASS;
                goto retry;
        }

        OSBitAndAtomic(~((uint32_t)P_SELECT), &p->p_flag);

        /* if the select is just for timeout skip check */
        if (seldata->count && (sel_pass == SEL_SECONDPASS))
                panic("selprocess: 2nd pass assertwaiting");

        /* waitq_set has waitqueue as first element */
        wait_result = waitq_assert_wait64_leeway((struct waitq *)uth->uu_wqset,
                                                 NO_EVENT64, THREAD_ABORTSAFE,
                                                 TIMEOUT_URGENCY_USER_NORMAL,
                                                 seldata->abstime,
                                                 TIMEOUT_NO_LEEWAY);
        if (wait_result != THREAD_AWAKENED) {
                /* there are no preposted events */
                error = tsleep1(NULL, PSOCK | PCATCH,
                                "select", 0, selcontinue);
        } else  {
                prepost = 1;
                error = 0;
        }

        if (error == 0) {
                sel_pass = SEL_SECONDPASS;
                if (!prepost)
                        somewakeup = 1;
                goto retry;
        }
done:
        if (unwind) {
                seldrop(p, sel->ibits, uap->nd);
                waitq_set_deinit(uth->uu_wqset);
                /*
                 * zero out the waitq pointer array to avoid use-after free
                 * errors in the selcount error path (seldrop_locked) if/when
                 * the thread re-calls select().
                 */
                bzero((void *)uth->uu_wqset, uth->uu_wqstate_sz);
        }
        OSBitAndAtomic(~((uint32_t)P_SELECT), &p->p_flag);
        /* select is not restarted after signals... */
        if (error == ERESTART)
                error = EINTR;
        if (error == EWOULDBLOCK)
                error = 0;
        nw = howmany(uap->nd, NFDBITS);
        ni = nw * sizeof(fd_mask);

#define putbits(name, x) \
        do { \
                if (uap->name && (error2 = \
                        copyout((caddr_t)&sel->obits[(x) * nw], uap->name, ni))) \
                        error = error2; \
        } while (0)

        if (error == 0) {
                int error2;

                putbits(in, 0);
                putbits(ou, 1);
                putbits(ex, 2);
#undef putbits
        }

        if (error != EINTR && sel_pass == SEL_SECONDPASS && uth->uu_flag & UT_SAS_OLDMASK) {
                /* restore signal mask - continuation case */
                uth->uu_sigmask = uth->uu_oldmask;
                uth->uu_oldmask = 0;
                uth->uu_flag &= ~UT_SAS_OLDMASK;
        }

        return(error);
}


/**
 * remove the fileproc's underlying waitq from the supplied waitq set;
 * clear FP_INSELECT when appropriate
 *
 * Parameters:
 *              fp      File proc that is potentially currently in select
 *              wqset   Waitq set to which the fileproc may belong
 *                      (usually this is the thread's private waitq set)
 * Conditions:
 *              proc_fdlock is held
 */
static void selunlinkfp(struct fileproc *fp, uint64_t wqp_id, struct waitq_set *wqset)
{
        int valid_set = waitq_set_is_valid(wqset);
        int valid_q = !!wqp_id;

        /*
         * This could be called (from selcount error path) before we setup
         * the thread's wqset. Check the wqset passed in, and only unlink if
         * the set is valid.
         */

        /* unlink the underlying waitq from the input set (thread waitq set) */
        if (valid_q && valid_set)
                waitq_unlink_by_prepost_id(wqp_id, wqset);

        /* allow passing a NULL/invalid fp for seldrop unwind */
        if (!fp || !(fp->f_flags & (FP_INSELECT|FP_SELCONFLICT)))
                return;

        /*
         * We can always remove the conflict queue from our thread's set: this
         * will not affect other threads that potentially need to be awoken on
         * the conflict queue during a fileproc_drain - those sets will still
         * be linked with the global conflict queue, and the last waiter
         * on the fp clears the CONFLICT marker.
         */
        if (valid_set && (fp->f_flags & FP_SELCONFLICT))
                waitq_unlink(&select_conflict_queue, wqset);

        /* jca: TODO:
         * This isn't quite right - we don't actually know if this
         * fileproc is in another select or not! Here we just assume
         * that if we were the first thread to select on the FD, then
         * we'll be the one to clear this flag...
         */
        if (valid_set && fp->f_wset == (void *)wqset) {
                fp->f_flags &= ~FP_INSELECT;
                fp->f_wset = NULL;
        }
}

/**
 * connect a fileproc to the given wqset, potentially bridging to a waitq
 * pointed to indirectly by wq_data
 *
 * Parameters:
 *              fp      File proc potentially currently in select
 *              wq_data Pointer to a pointer to a waitq (could be NULL)
 *              wqset   Waitq set to which the fileproc should now belong
 *                      (usually this is the thread's private waitq set)
 *
 * Conditions:
 *              proc_fdlock is held
 */
static uint64_t sellinkfp(struct fileproc *fp, void **wq_data, struct waitq_set *wqset)
{
        struct waitq *f_wq = NULL;

        if ((fp->f_flags & FP_INSELECT) != FP_INSELECT) {
                if (wq_data)
                        panic("non-null data:%p on fp:%p not in select?!"
                              "(wqset:%p)", wq_data, fp, wqset);
                return 0;
        }

        if ((fp->f_flags & FP_SELCONFLICT) == FP_SELCONFLICT) {
                waitq_link(&select_conflict_queue, wqset, WAITQ_SHOULD_LOCK, NULL);
        }

        /*
         * The wq_data parameter has potentially been set by selrecord called
         * from a subsystems fo_select() function. If the subsystem does not
         * call selrecord, then wq_data will be NULL
         *
         * Use memcpy to get the value into a proper pointer because
         * wq_data most likely points to a stack variable that could be
         * unaligned on 32-bit systems.
         */
        if (wq_data) {
                memcpy(&f_wq, wq_data, sizeof(f_wq));
                if (!waitq_is_valid(f_wq))
                        f_wq = NULL;
        }

        /* record the first thread's wqset in the fileproc structure */
        if (!fp->f_wset)
                fp->f_wset = (void *)wqset;

        /* handles NULL f_wq */
        return waitq_get_prepost_id(f_wq);
}


/*
 * selscan
 *
 * Parameters:  p                       Process performing the select
 *              sel                     The per-thread select context structure
 *              nfd                     The number of file descriptors to scan
 *              retval                  The per thread system call return area
 *              sel_pass                Which pass this is; allowed values are
 *                                              SEL_FIRSTPASS and SEL_SECONDPASS
 *              wqset                   The per thread wait queue set
 *
 * Returns:     0                       Success
 *              EIO                     Invalid p->p_fd field XXX Obsolete?
 *              EBADF                   One of the files in the bit vector is
 *                                              invalid.
 */
static int
selscan(struct proc *p, struct _select *sel, struct _select_data * seldata,
        int nfd, int32_t *retval, int sel_pass, struct waitq_set *wqset)
{
        struct filedesc *fdp = p->p_fd;
        int msk, i, j, fd;
        u_int32_t bits;
        struct fileproc *fp;
        int n = 0;              /* count of bits */
        int nc = 0;             /* bit vector offset (nc'th bit) */
        static int flag[3] = { FREAD, FWRITE, 0 };
        u_int32_t *iptr, *optr;
        u_int nw;
        u_int32_t *ibits, *obits;
        uint64_t reserved_link, *rl_ptr = NULL;
        int count;
        struct vfs_context context = *vfs_context_current();

        /*
         * Problems when reboot; due to MacOSX signal probs
         * in Beaker1C ; verify that the p->p_fd is valid
         */
        if (fdp == NULL) {
                *retval=0;
                return(EIO);
        }
        ibits = sel->ibits;
        obits = sel->obits;

        nw = howmany(nfd, NFDBITS);

        count = seldata->count;

        nc = 0;
        if (!count) {
                *retval = 0;
                return 0;
        }

        proc_fdlock(p);
        for (msk = 0; msk < 3; msk++) {
                iptr = (u_int32_t *)&ibits[msk * nw];
                optr = (u_int32_t *)&obits[msk * nw];

                for (i = 0; i < nfd; i += NFDBITS) {
                        bits = iptr[i/NFDBITS];

                        while ((j = ffs(bits)) && (fd = i + --j) < nfd) {
                                bits &= ~(1 << j);

                                if (fd < fdp->fd_nfiles)
                                        fp = fdp->fd_ofiles[fd];
                                else
                                        fp = NULL;

                                if (fp == NULL || (fdp->fd_ofileflags[fd] & UF_RESERVED)) {
                                        /*
                                         * If we abort because of a bad
                                         * fd, let the caller unwind...
                                         */
                                        proc_fdunlock(p);
                                        return(EBADF);
                                }
                                if (sel_pass == SEL_SECONDPASS) {
                                        reserved_link = 0;
                                        rl_ptr = NULL;
                                        selunlinkfp(fp, seldata->wqp[nc], wqset);
                                } else {
                                        reserved_link = waitq_link_reserve((struct waitq *)wqset);
                                        rl_ptr = &reserved_link;
                                        if (fp->f_flags & FP_INSELECT)
                                                /* someone is already in select on this fp */
                                                fp->f_flags |= FP_SELCONFLICT;
                                        else
                                                fp->f_flags |= FP_INSELECT;

                                        waitq_set_lazy_init_link(wqset);
                                }

                                context.vc_ucred = fp->f_cred;

                                /*
                                 * stash this value b/c fo_select may replace
                                 * reserved_link with a pointer to a waitq object
                                 */
                                uint64_t rsvd = reserved_link;

                                /* The select; set the bit, if true */
                                if (fp->f_ops && fp->f_type
                                        && fo_select(fp, flag[msk], rl_ptr, &context)) {
                                        optr[fd/NFDBITS] |= (1 << (fd % NFDBITS));
                                        n++;
                                }
                                if (sel_pass == SEL_FIRSTPASS) {
                                        waitq_link_release(rsvd);
                                        /*
                                         * If the fp's supporting selinfo structure was linked
                                         * to this thread's waitq set, then 'reserved_link'
                                         * will have been updated by selrecord to be a pointer
                                         * to the selinfo's waitq.
                                         */
                                        if (reserved_link == rsvd)
                                                rl_ptr = NULL; /* fo_select never called selrecord() */
                                        /*
                                         * Hook up the thread's waitq set either to
                                         * the fileproc structure, or to the global
                                         * conflict queue: but only on the first
                                         * select pass.
                                         */
                                        seldata->wqp[nc] = sellinkfp(fp, (void **)rl_ptr, wqset);
                                }
                                nc++;
                        }
                }
        }
        proc_fdunlock(p);

        *retval = n;
        return (0);
}

int poll_callback(struct kqueue *, struct kevent_internal_s *, void *);

struct poll_continue_args {
        user_addr_t pca_fds;
        u_int pca_nfds;
        u_int pca_rfds;
};

int
poll(struct proc *p, struct poll_args *uap, int32_t *retval)
{
        __pthread_testcancel(1);
        return(poll_nocancel(p, (struct poll_nocancel_args *)uap, retval));
}


int
poll_nocancel(struct proc *p, struct poll_nocancel_args *uap, int32_t *retval)
{
        struct poll_continue_args *cont;
        struct pollfd *fds;
        struct kqueue *kq;
        struct timeval atv;
        int ncoll, error = 0;
        u_int nfds = uap->nfds;
        u_int rfds = 0;
        u_int i;
        size_t ni;

        /*
         * This is kinda bogus.  We have fd limits, but that is not
         * really related to the size of the pollfd array.  Make sure
         * we let the process use at least FD_SETSIZE entries and at
         * least enough for the current limits.  We want to be reasonably
         * safe, but not overly restrictive.
         */
        if (nfds > OPEN_MAX ||
            (nfds > p->p_rlimit[RLIMIT_NOFILE].rlim_cur && (proc_suser(p) || nfds > FD_SETSIZE)))
                return (EINVAL);

        kq = kqueue_alloc(p, 0);
        if (kq == NULL)
                return (EAGAIN);

        ni = nfds * sizeof(struct pollfd) + sizeof(struct poll_continue_args);
        MALLOC(cont, struct poll_continue_args *, ni, M_TEMP, M_WAITOK);
        if (NULL == cont) {
                error = EAGAIN;
                goto out;
        }
        
        fds = (struct pollfd *)&cont[1];
        error = copyin(uap->fds, fds, nfds * sizeof(struct pollfd));
        if (error)
                goto out;

        if (uap->timeout != -1) {
                struct timeval rtv;

                atv.tv_sec = uap->timeout / 1000;
                atv.tv_usec = (uap->timeout % 1000) * 1000;
                if (itimerfix(&atv)) {
                        error = EINVAL;
                        goto out;
                }
                getmicrouptime(&rtv);
                timevaladd(&atv, &rtv);
        } else {
                atv.tv_sec = 0;
                atv.tv_usec = 0;
        }

        /* JMM - all this P_SELECT stuff is bogus */
        ncoll = nselcoll;
        OSBitOrAtomic(P_SELECT, &p->p_flag);
        for (i = 0; i < nfds; i++) {
                short events = fds[i].events;
                KNOTE_LOCK_CTX(knlc);
                __assert_only int rc;

                /* per spec, ignore fd values below zero */
                if (fds[i].fd < 0) {
                        fds[i].revents = 0;
                        continue;
                }

                /* convert the poll event into a kqueue kevent */
                struct kevent_internal_s kev = {
                        .ident = fds[i].fd,
                        .flags = EV_ADD | EV_ONESHOT | EV_POLL,
                        .udata = CAST_USER_ADDR_T(&fds[i]) };

                /* Handle input events */
                if (events & ( POLLIN | POLLRDNORM | POLLPRI | POLLRDBAND | POLLHUP )) {
                        kev.filter = EVFILT_READ;
                        if (events & ( POLLPRI | POLLRDBAND ))
                                kev.flags |= EV_OOBAND;
                        rc = kevent_register(kq, &kev, &knlc);
                        assert((rc & FILTER_REGISTER_WAIT) == 0);
                }

                /* Handle output events */
                if ((kev.flags & EV_ERROR) == 0 &&
                    (events & ( POLLOUT | POLLWRNORM | POLLWRBAND ))) {
                        kev.filter = EVFILT_WRITE;
                        rc = kevent_register(kq, &kev, &knlc);
                        assert((rc & FILTER_REGISTER_WAIT) == 0);
                }

                /* Handle BSD extension vnode events */
                if ((kev.flags & EV_ERROR) == 0 &&
                    (events & ( POLLEXTEND | POLLATTRIB | POLLNLINK | POLLWRITE ))) {
                        kev.filter = EVFILT_VNODE;
                        kev.fflags = 0;
                        if (events & POLLEXTEND)
                                kev.fflags |= NOTE_EXTEND;
                        if (events & POLLATTRIB)
                                kev.fflags |= NOTE_ATTRIB;
                        if (events & POLLNLINK)
                                kev.fflags |= NOTE_LINK;
                        if (events & POLLWRITE)
                                kev.fflags |= NOTE_WRITE;
                        rc = kevent_register(kq, &kev, &knlc);
                        assert((rc & FILTER_REGISTER_WAIT) == 0);
                }

                if (kev.flags & EV_ERROR) {
                        fds[i].revents = POLLNVAL;
                        rfds++;
                } else
                        fds[i].revents = 0;
        }

        /*
         * Did we have any trouble registering?
         * If user space passed 0 FDs, then respect any timeout value passed.
         * This is an extremely inefficient sleep. If user space passed one or
         * more FDs, and we had trouble registering _all_ of them, then bail
         * out. If a subset of the provided FDs failed to register, then we
         * will still call the kqueue_scan function.
         */
        if (nfds && (rfds == nfds))
                goto done;

        /*
         * If any events have trouble registering, an event has fired and we
         * shouldn't wait for events in kqueue_scan -- use the current time as
         * the deadline.
         */
        if (rfds)
                getmicrouptime(&atv);

        /* scan for, and possibly wait for, the kevents to trigger */
        cont->pca_fds = uap->fds;
        cont->pca_nfds = nfds;
        cont->pca_rfds = rfds;
        error = kqueue_scan(kq, poll_callback, NULL, cont, NULL, &atv, p);
        rfds = cont->pca_rfds;

 done:
        OSBitAndAtomic(~((uint32_t)P_SELECT), &p->p_flag);
        /* poll is not restarted after signals... */
        if (error == ERESTART)
                error = EINTR;
        if (error == EWOULDBLOCK)
                error = 0;
        if (error == 0) {
                error = copyout(fds, uap->fds, nfds * sizeof(struct pollfd));
                *retval = rfds;
        }

 out:
        if (NULL != cont)
                FREE(cont, M_TEMP);

        kqueue_dealloc(kq);
        return (error);
}

int
poll_callback(__unused struct kqueue *kq, struct kevent_internal_s *kevp, void *data)
{
        struct poll_continue_args *cont = (struct poll_continue_args *)data;
        struct pollfd *fds = CAST_DOWN(struct pollfd *, kevp->udata);
        short prev_revents = fds->revents;
        short mask = 0;

        /* convert the results back into revents */
        if (kevp->flags & EV_EOF)
                fds->revents |= POLLHUP;
        if (kevp->flags & EV_ERROR)
                fds->revents |= POLLERR;

        switch (kevp->filter) {
        case EVFILT_READ:
                if (fds->revents & POLLHUP)
                        mask = (POLLIN | POLLRDNORM | POLLPRI | POLLRDBAND );
                else {
                        mask = (POLLIN | POLLRDNORM);
                        if (kevp->flags & EV_OOBAND)
                                mask |= (POLLPRI | POLLRDBAND);
                }
                fds->revents |= (fds->events & mask);
                break;

        case EVFILT_WRITE:
                if (!(fds->revents & POLLHUP))
                        fds->revents |= (fds->events & ( POLLOUT | POLLWRNORM | POLLWRBAND ));
                break;

        case EVFILT_VNODE:
                if (kevp->fflags & NOTE_EXTEND)
                        fds->revents |= (fds->events & POLLEXTEND);
                if (kevp->fflags & NOTE_ATTRIB)
                        fds->revents |= (fds->events & POLLATTRIB);
                if (kevp->fflags & NOTE_LINK)
                        fds->revents |= (fds->events & POLLNLINK);
                if (kevp->fflags & NOTE_WRITE)
                        fds->revents |= (fds->events & POLLWRITE);
                break;
        }

        if (fds->revents != 0 && prev_revents == 0)
                cont->pca_rfds++;

        return 0;
}
        
int
seltrue(__unused dev_t dev, __unused int flag, __unused struct proc *p)
{

        return (1);
}

/*
 * selcount
 *
 * Count the number of bits set in the input bit vector, and establish an
 * outstanding fp->f_iocount for each of the descriptors which will be in
 * use in the select operation.
 *
 * Parameters:  p                       The process doing the select
 *              ibits                   The input bit vector
 *              nfd                     The number of fd's in the vector
 *              countp                  Pointer to where to store the bit count
 *
 * Returns:     0                       Success
 *              EIO                     Bad per process open file table
 *              EBADF                   One of the bits in the input bit vector
 *                                              references an invalid fd
 *
 * Implicit:    *countp (modified)      Count of fd's
 *
 * Notes:       This function is the first pass under the proc_fdlock() that
 *              permits us to recognize invalid descriptors in the bit vector;
 *              the may, however, not remain valid through the drop and
 *              later reacquisition of the proc_fdlock().
 */
static int
selcount(struct proc *p, u_int32_t *ibits, int nfd, int *countp)
{
        struct filedesc *fdp = p->p_fd;
        int msk, i, j, fd;
        u_int32_t bits;
        struct fileproc *fp;
        int n = 0;
        u_int32_t *iptr;
        u_int nw;
        int error=0; 
        int dropcount;
        int need_wakeup = 0;

        /*
         * Problems when reboot; due to MacOSX signal probs
         * in Beaker1C ; verify that the p->p_fd is valid
         */
        if (fdp == NULL) {
                *countp = 0;
                return(EIO);
        }
        nw = howmany(nfd, NFDBITS);

        proc_fdlock(p);
        for (msk = 0; msk < 3; msk++) {
                iptr = (u_int32_t *)&ibits[msk * nw];
                for (i = 0; i < nfd; i += NFDBITS) {
                        bits = iptr[i/NFDBITS];
                        while ((j = ffs(bits)) && (fd = i + --j) < nfd) {
                                bits &= ~(1 << j);

                                if (fd < fdp->fd_nfiles)
                                        fp = fdp->fd_ofiles[fd];
                                else
                                        fp = NULL;

                                if (fp == NULL ||
                                        (fdp->fd_ofileflags[fd] & UF_RESERVED)) {
                                                *countp = 0;
                                                error = EBADF;
                                                goto bad;
                                }
                                fp->f_iocount++;
                                n++;
                        }
                }
        }
        proc_fdunlock(p);

        *countp = n;
        return (0);

bad:
        dropcount = 0;
        
        if (n == 0)
                goto out;
        /* Ignore error return; it's already EBADF */
        (void)seldrop_locked(p, ibits, nfd, n, &need_wakeup, 1);

out:
        proc_fdunlock(p);
        if (need_wakeup) {
                wakeup(&p->p_fpdrainwait);
        }
        return(error);
}


/*
 * seldrop_locked
 *
 * Drop outstanding wait queue references set up during selscan(); drop the
 * outstanding per fileproc f_iocount() picked up during the selcount().
 *
 * Parameters:  p                       Process performing the select
 *              ibits                   Input bit bector of fd's
 *              nfd                     Number of fd's
 *              lim                     Limit to number of vector entries to
 *                                              consider, or -1 for "all"
 *              inselect                True if
 *              need_wakeup             Pointer to flag to set to do a wakeup
 *                                      if f_iocont on any descriptor goes to 0
 *
 * Returns:     0                       Success
 *              EBADF                   One or more fds in the bit vector
 *                                              were invalid, but the rest
 *                                              were successfully dropped
 *
 * Notes:       An fd make become bad while the proc_fdlock() is not held,
 *              if a multithreaded application closes the fd out from under
 *              the in progress select.  In this case, we still have to
 *              clean up after the set up on the remaining fds.
 */
static int
seldrop_locked(struct proc *p, u_int32_t *ibits, int nfd, int lim, int *need_wakeup, int fromselcount)
{
        struct filedesc *fdp = p->p_fd;
        int msk, i, j, nc, fd;
        u_int32_t bits;
        struct fileproc *fp;
        u_int32_t *iptr;
        u_int nw;
        int error = 0;
        int dropcount = 0;
        uthread_t uth = get_bsdthread_info(current_thread());
        struct _select_data *seldata;

        *need_wakeup = 0;

        /*
         * Problems when reboot; due to MacOSX signal probs
         * in Beaker1C ; verify that the p->p_fd is valid
         */
        if (fdp == NULL) {
                return(EIO);
        }

        nw = howmany(nfd, NFDBITS);
        seldata = &uth->uu_save.uus_select_data;

        nc = 0;
        for (msk = 0; msk < 3; msk++) {
                iptr = (u_int32_t *)&ibits[msk * nw];
                for (i = 0; i < nfd; i += NFDBITS) {
                        bits = iptr[i/NFDBITS];
                        while ((j = ffs(bits)) && (fd = i + --j) < nfd) {
                                bits &= ~(1 << j);
                                fp = fdp->fd_ofiles[fd];
                                /*
                                 * If we've already dropped as many as were
                                 * counted/scanned, then we are done.  
                                 */
                                if ((fromselcount != 0) && (++dropcount > lim))
                                        goto done;

                                /*
                                 * unlink even potentially NULL fileprocs.
                                 * If the FD was closed from under us, we
                                 * still need to cleanup the waitq links!
                                 */
                                selunlinkfp(fp,
                                            seldata->wqp ? seldata->wqp[nc] : 0,
                                            uth->uu_wqset);

                                nc++;

                                if (fp == NULL) {
                                        /* skip (now) bad fds */
                                        error = EBADF;
                                        continue;
                                }

                                fp->f_iocount--;
                                if (fp->f_iocount < 0)
                                        panic("f_iocount overdecrement!");

                                if (fp->f_iocount == 0) {
                                        /*
                                         * The last iocount is responsible for clearing
                                         * selconfict flag - even if we didn't set it -
                                         * and is also responsible for waking up anyone
                                         * waiting on iocounts to drain.
                                         */
                                        if (fp->f_flags & FP_SELCONFLICT)
                                                fp->f_flags &= ~FP_SELCONFLICT;
                                        if (p->p_fpdrainwait) {
                                                p->p_fpdrainwait = 0;
                                                *need_wakeup = 1;
                                        }
                                }
                        }
                }
        }
done:
        return (error);
}


static int
seldrop(struct proc *p, u_int32_t *ibits, int nfd)
{
        int error;
        int need_wakeup = 0;

        proc_fdlock(p);
        error =  seldrop_locked(p, ibits, nfd, nfd, &need_wakeup, 0);
        proc_fdunlock(p);
        if (need_wakeup) {
                wakeup(&p->p_fpdrainwait);
        }
        return (error);
}

/*
 * Record a select request.
 */
void
selrecord(__unused struct proc *selector, struct selinfo *sip, void *s_data)
{
        thread_t        cur_act = current_thread();
        struct uthread * ut = get_bsdthread_info(cur_act);
        /* on input, s_data points to the 64-bit ID of a reserved link object */
        uint64_t *reserved_link = (uint64_t *)s_data;

        /* need to look at collisions */

        /*do not record if this is second pass of select */
        if (!s_data)
                return;

        if ((sip->si_flags & SI_INITED) == 0) {
                waitq_init(&sip->si_waitq, SYNC_POLICY_FIFO);
                sip->si_flags |= SI_INITED;
                sip->si_flags &= ~SI_CLEAR;
        }

        if (sip->si_flags & SI_RECORDED)
                sip->si_flags |= SI_COLL;
        else
                sip->si_flags &= ~SI_COLL;

        sip->si_flags |= SI_RECORDED;
        /* note: this checks for pre-existing linkage */
        waitq_link(&sip->si_waitq, ut->uu_wqset,
                   WAITQ_SHOULD_LOCK, reserved_link);

        /*
         * Always consume the reserved link.
         * We can always call waitq_link_release() safely because if
         * waitq_link is successful, it consumes the link and resets the
         * value to 0, in which case our call to release becomes a no-op.
         * If waitq_link fails, then the following release call will actually
         * release the reserved link object.
         */
        waitq_link_release(*reserved_link);
        *reserved_link = 0;

        /*
         * Use the s_data pointer as an output parameter as well
         * This avoids changing the prototype for this function which is
         * used by many kexts. We need to surface the waitq object
         * associated with the selinfo we just added to the thread's select
         * set. New waitq sets do not have back-pointers to set members, so
         * the only way to clear out set linkage objects is to go from the
         * waitq to the set. We use a memcpy because s_data could be
         * pointing to an unaligned value on the stack
         * (especially on 32-bit systems)
         */
        void *wqptr = (void *)&sip->si_waitq;
        memcpy((void *)s_data, (void *)&wqptr, sizeof(void *));

        return;
}

void
selwakeup(struct selinfo *sip)
{
        
        if ((sip->si_flags & SI_INITED) == 0) {
                return;
        }

        if (sip->si_flags & SI_COLL) {
                nselcoll++;
                sip->si_flags &= ~SI_COLL;
#if 0
                /* will not  support */
                //wakeup((caddr_t)&selwait);
#endif
        }

        if (sip->si_flags & SI_RECORDED) {
                waitq_wakeup64_all(&sip->si_waitq, NO_EVENT64,
                                   THREAD_AWAKENED, WAITQ_ALL_PRIORITIES);
                sip->si_flags &= ~SI_RECORDED;
        }

}

void 
selthreadclear(struct selinfo *sip)
{
        struct waitq *wq;

        if ((sip->si_flags & SI_INITED) == 0) {
                return;
        }
        if (sip->si_flags & SI_RECORDED) {
                        selwakeup(sip);
                        sip->si_flags &= ~(SI_RECORDED | SI_COLL);
        }
        sip->si_flags |= SI_CLEAR;
        sip->si_flags &= ~SI_INITED;

        wq = &sip->si_waitq;

        /*
         * Higher level logic may have a handle on this waitq's prepost ID,
         * but that's OK because the waitq_deinit will remove/invalidate the
         * prepost object (as well as mark the waitq invalid). This de-couples
         * us from any callers that may have a handle to this waitq via the
         * prepost ID.
         */
        waitq_deinit(wq);
}




#define DBG_POST        0x10
#define DBG_WATCH       0x11
#define DBG_WAIT        0x12
#define DBG_MOD         0x13
#define DBG_EWAKEUP     0x14
#define DBG_ENQUEUE     0x15
#define DBG_DEQUEUE     0x16

#define DBG_MISC_POST MISCDBG_CODE(DBG_EVENT,DBG_POST)
#define DBG_MISC_WATCH MISCDBG_CODE(DBG_EVENT,DBG_WATCH)
#define DBG_MISC_WAIT MISCDBG_CODE(DBG_EVENT,DBG_WAIT)
#define DBG_MISC_MOD MISCDBG_CODE(DBG_EVENT,DBG_MOD)
#define DBG_MISC_EWAKEUP MISCDBG_CODE(DBG_EVENT,DBG_EWAKEUP)
#define DBG_MISC_ENQUEUE MISCDBG_CODE(DBG_EVENT,DBG_ENQUEUE)
#define DBG_MISC_DEQUEUE MISCDBG_CODE(DBG_EVENT,DBG_DEQUEUE)


#define EVPROCDEQUE(p, evq)     do {                            \
        proc_lock(p);                                           \
        if (evq->ee_flags & EV_QUEUED) {                        \
                TAILQ_REMOVE(&p->p_evlist, evq, ee_plist);      \
                evq->ee_flags &= ~EV_QUEUED;                    \
        }                                                       \
        proc_unlock(p);                                         \
} while (0);


/*
 * called upon socket close. deque and free all events for
 * the socket...  socket must be locked by caller.
 */
void
evsofree(struct socket *sp)
{
        struct eventqelt *evq, *next;
        proc_t  p;

        if (sp == NULL)
                return;

        for (evq = sp->so_evlist.tqh_first; evq != NULL; evq = next) {
                next = evq->ee_slist.tqe_next;
                p = evq->ee_proc;

                if (evq->ee_flags & EV_QUEUED) {
                        EVPROCDEQUE(p, evq);
                }
                TAILQ_REMOVE(&sp->so_evlist, evq, ee_slist); // remove from socket q
                FREE(evq, M_TEMP);
        }
}


/*
 * called upon pipe close. deque and free all events for
 * the pipe... pipe must be locked by caller
 */
void
evpipefree(struct pipe *cpipe)
{
        struct eventqelt *evq, *next;
        proc_t  p;

        for (evq = cpipe->pipe_evlist.tqh_first; evq != NULL; evq = next) {
                next = evq->ee_slist.tqe_next;
                p = evq->ee_proc;

                EVPROCDEQUE(p, evq);

                TAILQ_REMOVE(&cpipe->pipe_evlist, evq, ee_slist); // remove from pipe q
                FREE(evq, M_TEMP);
        }
}


/*
 * enqueue this event if it's not already queued. wakeup
 * the proc if we do queue this event to it...
 * entered with proc lock held... we drop it before
 * doing the wakeup and return in that state
 */
static void
evprocenque(struct eventqelt *evq)
{
        proc_t  p;

        assert(evq);
        p = evq->ee_proc;

        KERNEL_DEBUG(DBG_MISC_ENQUEUE|DBG_FUNC_START, (uint32_t)evq, evq->ee_flags, evq->ee_eventmask,0,0);

        proc_lock(p);

        if (evq->ee_flags & EV_QUEUED) {
                proc_unlock(p);

                KERNEL_DEBUG(DBG_MISC_ENQUEUE|DBG_FUNC_END, 0,0,0,0,0);
                return;
        }
        evq->ee_flags |= EV_QUEUED;

        TAILQ_INSERT_TAIL(&p->p_evlist, evq, ee_plist);

        proc_unlock(p);

        wakeup(&p->p_evlist);

        KERNEL_DEBUG(DBG_MISC_ENQUEUE|DBG_FUNC_END, 0,0,0,0,0);
}


/*
 * pipe lock must be taken by the caller
 */
void
postpipeevent(struct pipe *pipep, int event)
{
        int     mask;
        struct eventqelt *evq;

        if (pipep == NULL)
                return;
        KERNEL_DEBUG(DBG_MISC_POST|DBG_FUNC_START, event,0,0,1,0);

        for (evq = pipep->pipe_evlist.tqh_first;
             evq != NULL; evq = evq->ee_slist.tqe_next) {

                if (evq->ee_eventmask == 0)
                        continue;
                mask = 0;

                switch (event & (EV_RWBYTES | EV_RCLOSED | EV_WCLOSED)) {

                case EV_RWBYTES:
                  if ((evq->ee_eventmask & EV_RE) && pipep->pipe_buffer.cnt) {
                          mask |= EV_RE;
                          evq->ee_req.er_rcnt = pipep->pipe_buffer.cnt;
                  }
                  if ((evq->ee_eventmask & EV_WR) && 
                      (MAX(pipep->pipe_buffer.size,PIPE_SIZE) - pipep->pipe_buffer.cnt) >= PIPE_BUF) {

                          if (pipep->pipe_state & PIPE_EOF) {
                                  mask |= EV_WR|EV_RESET;
                                  break;
                          }
                          mask |= EV_WR;
                          evq->ee_req.er_wcnt = MAX(pipep->pipe_buffer.size, PIPE_SIZE) - pipep->pipe_buffer.cnt;
                  }
                  break;

                case EV_WCLOSED:
                case EV_RCLOSED:
                  if ((evq->ee_eventmask & EV_RE)) {
                          mask |= EV_RE|EV_RCLOSED;
                  }
                  if ((evq->ee_eventmask & EV_WR)) {
                          mask |= EV_WR|EV_WCLOSED;
                  }
                  break;

                default:
                  return;
                }
                if (mask) {
                        /*
                         * disarm... postevents are nops until this event is 'read' via
                         * waitevent and then re-armed via modwatch
                         */
                        evq->ee_eventmask = 0;

                        /*
                         * since events are disarmed until after the waitevent
                         * the ee_req.er_xxxx fields can't change once we've
                         * inserted this event into the proc queue...
                         * therefore, the waitevent will see a 'consistent'
                         * snapshot of the event, even though it won't hold
                         * the pipe lock, and we're updating the event outside
                         * of the proc lock, which it will hold
                         */
                        evq->ee_req.er_eventbits |= mask;

                        KERNEL_DEBUG(DBG_MISC_POST, (uint32_t)evq, evq->ee_req.er_eventbits, mask, 1,0);

                        evprocenque(evq);
                }
        }
        KERNEL_DEBUG(DBG_MISC_POST|DBG_FUNC_END, 0,0,0,1,0);
}

#if SOCKETS
/*
 * given either a sockbuf or a socket run down the
 * event list and queue ready events found...
 * the socket must be locked by the caller
 */
void
postevent(struct socket *sp, struct sockbuf *sb, int event)
{
        int     mask;
        struct  eventqelt *evq;
        struct  tcpcb *tp;

        if (sb)
                sp = sb->sb_so;
        if (sp == NULL)
                return;

        KERNEL_DEBUG(DBG_MISC_POST|DBG_FUNC_START, (int)sp, event, 0, 0, 0);

        for (evq = sp->so_evlist.tqh_first;
             evq != NULL; evq = evq->ee_slist.tqe_next) {

                if (evq->ee_eventmask == 0)
                        continue;
                mask = 0;

                /* ready for reading:
                   - byte cnt >= receive low water mark
                   - read-half of conn closed
                   - conn pending for listening sock
                   - socket error pending

                   ready for writing
                   - byte cnt avail >= send low water mark
                   - write half of conn closed
                   - socket error pending
                   - non-blocking conn completed successfully

                   exception pending
                   - out of band data
                   - sock at out of band mark
                */

                switch (event & EV_DMASK) {

                case EV_OOB:
                  if ((evq->ee_eventmask & EV_EX)) {
                          if (sp->so_oobmark || ((sp->so_state & SS_RCVATMARK)))
                                  mask |= EV_EX|EV_OOB;
                  }
                  break;

                case EV_RWBYTES|EV_OOB:
                  if ((evq->ee_eventmask & EV_EX)) {
                          if (sp->so_oobmark || ((sp->so_state & SS_RCVATMARK)))
                                  mask |= EV_EX|EV_OOB;
                  }
                  /*
                   * fall into the next case
                   */
                case EV_RWBYTES:
                  if ((evq->ee_eventmask & EV_RE) && soreadable(sp)) {
                          /* for AFP/OT purposes; may go away in future */
                          if ((SOCK_DOM(sp) == PF_INET ||
                              SOCK_DOM(sp) == PF_INET6) &&
                              SOCK_PROTO(sp) == IPPROTO_TCP &&
                              (sp->so_error == ECONNREFUSED ||
                              sp->so_error == ECONNRESET)) {
                                  if (sp->so_pcb == NULL ||
                                      sotoinpcb(sp)->inp_state ==
                                      INPCB_STATE_DEAD ||
                                      (tp = sototcpcb(sp)) == NULL ||
                                      tp->t_state == TCPS_CLOSED) {
                                          mask |= EV_RE|EV_RESET;
                                          break;
                                  }
                          }
                          mask |= EV_RE;
                          evq->ee_req.er_rcnt = sp->so_rcv.sb_cc;

                          if (sp->so_state & SS_CANTRCVMORE) {
                                  mask |= EV_FIN;
                                  break;
                          }
                  }
                  if ((evq->ee_eventmask & EV_WR) && sowriteable(sp)) {
                          /* for AFP/OT purposes; may go away in future */
                          if ((SOCK_DOM(sp) == PF_INET ||
                              SOCK_DOM(sp) == PF_INET6) &&
                              SOCK_PROTO(sp) == IPPROTO_TCP &&
                              (sp->so_error == ECONNREFUSED ||
                              sp->so_error == ECONNRESET)) {
                                  if (sp->so_pcb == NULL ||
                                      sotoinpcb(sp)->inp_state ==
                                      INPCB_STATE_DEAD ||
                                      (tp = sototcpcb(sp)) == NULL ||
                                      tp->t_state == TCPS_CLOSED) {
                                          mask |= EV_WR|EV_RESET;
                                          break;
                                  }
                          }
                          mask |= EV_WR;
                          evq->ee_req.er_wcnt = sbspace(&sp->so_snd);
                  }
                  break;

                case EV_RCONN:
                  if ((evq->ee_eventmask & EV_RE)) {
                          mask |= EV_RE|EV_RCONN;
                          evq->ee_req.er_rcnt = sp->so_qlen + 1;  // incl this one
                  }
                  break;

                case EV_WCONN:
                  if ((evq->ee_eventmask & EV_WR)) {
                          mask |= EV_WR|EV_WCONN;
                  }
                  break;

                case EV_RCLOSED:
                  if ((evq->ee_eventmask & EV_RE)) {
                          mask |= EV_RE|EV_RCLOSED;
                  }
                  break;

                case EV_WCLOSED:
                  if ((evq->ee_eventmask & EV_WR)) {
                          mask |= EV_WR|EV_WCLOSED;
                  }
                  break;

                case EV_FIN:
                  if (evq->ee_eventmask & EV_RE) {
                          mask |= EV_RE|EV_FIN;
                  }
                  break;

                case EV_RESET:
                case EV_TIMEOUT:
                  if (evq->ee_eventmask & EV_RE) {
                          mask |= EV_RE | event;
                  } 
                  if (evq->ee_eventmask & EV_WR) {
                          mask |= EV_WR | event;
                  }
                  break;

                default:
                  KERNEL_DEBUG(DBG_MISC_POST|DBG_FUNC_END, (int)sp, -1, 0, 0, 0);
                  return;
                } /* switch */

                KERNEL_DEBUG(DBG_MISC_POST, (int)evq, evq->ee_eventmask, evq->ee_req.er_eventbits, mask, 0);

                if (mask) {
                        /*
                         * disarm... postevents are nops until this event is 'read' via
                         * waitevent and then re-armed via modwatch
                         */
                        evq->ee_eventmask = 0;

                        /*
                         * since events are disarmed until after the waitevent
                         * the ee_req.er_xxxx fields can't change once we've
                         * inserted this event into the proc queue...
                         * since waitevent can't see this event until we 
                         * enqueue it, waitevent will see a 'consistent'
                         * snapshot of the event, even though it won't hold
                         * the socket lock, and we're updating the event outside
                         * of the proc lock, which it will hold
                         */
                        evq->ee_req.er_eventbits |= mask;

                        evprocenque(evq);
                }
        }
        KERNEL_DEBUG(DBG_MISC_POST|DBG_FUNC_END, (int)sp, 0, 0, 0, 0);
}
#endif /* SOCKETS */


/*
 * watchevent system call. user passes us an event to watch
 * for. we malloc an event object, initialize it, and queue
 * it to the open socket. when the event occurs, postevent()
 * will enque it back to our proc where we can retrieve it
 * via waitevent().
 *
 * should this prevent duplicate events on same socket?
 *
 * Returns:
 *              ENOMEM                  No memory for operation
 *      copyin:EFAULT
 */
int
watchevent(proc_t p, struct watchevent_args *uap, __unused int *retval)
{
        struct eventqelt *evq = (struct eventqelt *)0;
        struct eventqelt *np = NULL;
        struct eventreq64 *erp;
        struct fileproc *fp = NULL;
        int error;

        KERNEL_DEBUG(DBG_MISC_WATCH|DBG_FUNC_START, 0,0,0,0,0);

        // get a qelt and fill with users req
        MALLOC(evq, struct eventqelt *, sizeof(struct eventqelt), M_TEMP, M_WAITOK);

        if (evq == NULL)
                return (ENOMEM);
        erp = &evq->ee_req;

        // get users request pkt

        if (IS_64BIT_PROCESS(p)) {
                error = copyin(uap->u_req, (caddr_t)erp, sizeof(struct eventreq64));
        } else {
                struct eventreq32 er32;

                error = copyin(uap->u_req, (caddr_t)&er32, sizeof(struct eventreq32));
                if (error == 0) {
                       /*
                        * the user only passes in the
                        * er_type, er_handle and er_data...
                        * the other fields are initialized
                        * below, so don't bother to copy
                        */
                        erp->er_type = er32.er_type;
                        erp->er_handle = er32.er_handle;
                        erp->er_data = (user_addr_t)er32.er_data;
                }
        }
        if (error) {
                FREE(evq, M_TEMP);
                KERNEL_DEBUG(DBG_MISC_WATCH|DBG_FUNC_END, error,0,0,0,0);

                return(error);          
        }
        KERNEL_DEBUG(DBG_MISC_WATCH, erp->er_handle,uap->u_eventmask,(uint32_t)evq,0,0);

        // validate, freeing qelt if errors
        error = 0;
        proc_fdlock(p);

        if (erp->er_type != EV_FD) {
                error = EINVAL;
        } else if ((error = fp_lookup(p, erp->er_handle, &fp, 1)) != 0) {
                error = EBADF;
#if SOCKETS
        } else if (fp->f_type == DTYPE_SOCKET) {
                socket_lock((struct socket *)fp->f_data, 1);
                np = ((struct socket *)fp->f_data)->so_evlist.tqh_first;
#endif /* SOCKETS */
        } else if (fp->f_type == DTYPE_PIPE) {
                PIPE_LOCK((struct pipe *)fp->f_data);
                np = ((struct pipe *)fp->f_data)->pipe_evlist.tqh_first;
        } else {
                fp_drop(p, erp->er_handle, fp, 1);
                error = EINVAL;
        }
        proc_fdunlock(p);

        if (error) {
                FREE(evq, M_TEMP);

                KERNEL_DEBUG(DBG_MISC_WATCH|DBG_FUNC_END, error,0,0,0,0);
                return(error);
        }
                
        /*
         * only allow one watch per file per proc
         */
        for ( ; np != NULL; np = np->ee_slist.tqe_next) {
                if (np->ee_proc == p) {
#if SOCKETS
                        if (fp->f_type == DTYPE_SOCKET)
                                socket_unlock((struct socket *)fp->f_data, 1);
                        else 
#endif /* SOCKETS */
                                PIPE_UNLOCK((struct pipe *)fp->f_data);
                        fp_drop(p, erp->er_handle, fp, 0);
                        FREE(evq, M_TEMP);
                        
                        KERNEL_DEBUG(DBG_MISC_WATCH|DBG_FUNC_END, EINVAL,0,0,0,0);
                        return(EINVAL);
                }
        }
        erp->er_ecnt = erp->er_rcnt = erp->er_wcnt = erp->er_eventbits = 0;
        evq->ee_proc = p;
        evq->ee_eventmask = uap->u_eventmask & EV_MASK;
        evq->ee_flags = 0;

#if SOCKETS
        if (fp->f_type == DTYPE_SOCKET) {
                TAILQ_INSERT_TAIL(&((struct socket *)fp->f_data)->so_evlist, evq, ee_slist);
                postevent((struct socket *)fp->f_data, 0, EV_RWBYTES); // catch existing events

                socket_unlock((struct socket *)fp->f_data, 1);
        } else
#endif /* SOCKETS */
        {
                TAILQ_INSERT_TAIL(&((struct pipe *)fp->f_data)->pipe_evlist, evq, ee_slist);
                postpipeevent((struct pipe *)fp->f_data, EV_RWBYTES);

                PIPE_UNLOCK((struct pipe *)fp->f_data);
        }
        fp_drop_event(p, erp->er_handle, fp);

        KERNEL_DEBUG(DBG_MISC_WATCH|DBG_FUNC_END, 0,0,0,0,0);
        return(0);
}



/*
 * waitevent system call.
 * grabs the next waiting event for this proc and returns
 * it. if no events, user can request to sleep with timeout
 * or without or poll mode
 *    ((tv != NULL && interval == 0) || tv == -1)
 */
int
waitevent(proc_t p, struct waitevent_args *uap, int *retval)
{
        int error = 0;
        struct eventqelt *evq;
        struct eventreq64 *erp;
        uint64_t abstime, interval;
        boolean_t fast_poll = FALSE;
        union {
                struct eventreq64 er64;
                struct eventreq32 er32;
        } uer = {};

        interval = 0;

        if (uap->tv) {
                struct timeval atv;
                /*
                 * check for fast poll method
                 */
                if (IS_64BIT_PROCESS(p)) {
                        if (uap->tv == (user_addr_t)-1)
                                fast_poll = TRUE;
                } else if (uap->tv == (user_addr_t)((uint32_t)-1))
                        fast_poll = TRUE;

                if (fast_poll == TRUE) {
                        if (p->p_evlist.tqh_first == NULL) {
                                KERNEL_DEBUG(DBG_MISC_WAIT|DBG_FUNC_NONE, -1,0,0,0,0);
                                /*
                                 * poll failed
                                 */
                                *retval = 1;
                                return (0);
                        }
                        proc_lock(p);
                        goto retry;
                }
                if (IS_64BIT_PROCESS(p)) {
                        struct user64_timeval atv64;
                        error = copyin(uap->tv, (caddr_t)&atv64, sizeof(atv64));
                        /* Loses resolution - assume timeout < 68 years */
                        atv.tv_sec = atv64.tv_sec;
                        atv.tv_usec = atv64.tv_usec;
                } else {
                        struct user32_timeval atv32;
                        error = copyin(uap->tv, (caddr_t)&atv32, sizeof(atv32));
                        atv.tv_sec = atv32.tv_sec;
                        atv.tv_usec = atv32.tv_usec;
                }

                if (error)
                        return(error);
                if (itimerfix(&atv)) {
                        error = EINVAL;
                        return(error);
                }
                interval = tvtoabstime(&atv);
        }
        KERNEL_DEBUG(DBG_MISC_WAIT|DBG_FUNC_START, 0,0,0,0,0);

        proc_lock(p);
retry:
        if ((evq = p->p_evlist.tqh_first) != NULL) {
                /*
                 * found one... make a local copy while it's still on the queue
                 * to prevent it from changing while in the midst of copying
                 * don't want to hold the proc lock across a copyout because
                 * it might block on a page fault at the target in user space
                 */
                erp = &evq->ee_req;

                if (IS_64BIT_PROCESS(p))
                        bcopy((caddr_t)erp, (caddr_t)&uer.er64, sizeof (struct eventreq64));
                else {
                        uer.er32.er_type  = erp->er_type;
                        uer.er32.er_handle  = erp->er_handle;
                        uer.er32.er_data  = (uint32_t)erp->er_data;
                        uer.er32.er_ecnt  = erp->er_ecnt;
                        uer.er32.er_rcnt  = erp->er_rcnt;
                        uer.er32.er_wcnt  = erp->er_wcnt;
                        uer.er32.er_eventbits = erp->er_eventbits;
                }
                TAILQ_REMOVE(&p->p_evlist, evq, ee_plist);

                evq->ee_flags &= ~EV_QUEUED;

                proc_unlock(p);

                if (IS_64BIT_PROCESS(p))
                        error = copyout((caddr_t)&uer.er64, uap->u_req, sizeof(struct eventreq64));
                else
                        error = copyout((caddr_t)&uer.er32, uap->u_req, sizeof(struct eventreq32));

                KERNEL_DEBUG(DBG_MISC_WAIT|DBG_FUNC_END, error,
                             evq->ee_req.er_handle,evq->ee_req.er_eventbits,(uint32_t)evq,0);
                return (error);
        }
        else {
                if (uap->tv && interval == 0) {
                        proc_unlock(p);
                        *retval = 1;  // poll failed

                        KERNEL_DEBUG(DBG_MISC_WAIT|DBG_FUNC_END, error,0,0,0,0);
                        return (error);
                }
                if (interval != 0)
                        clock_absolutetime_interval_to_deadline(interval, &abstime);
                else
                        abstime = 0;

                KERNEL_DEBUG(DBG_MISC_WAIT, 1,(uint32_t)&p->p_evlist,0,0,0);

                error = msleep1(&p->p_evlist, &p->p_mlock, (PSOCK | PCATCH), "waitevent", abstime);

                KERNEL_DEBUG(DBG_MISC_WAIT, 2,(uint32_t)&p->p_evlist,0,0,0);

                if (error == 0)
                        goto retry;
                if (error == ERESTART)
                        error = EINTR;
                if (error == EWOULDBLOCK) {
                        *retval = 1;
                        error = 0;
                }
        }
        proc_unlock(p);

        KERNEL_DEBUG(DBG_MISC_WAIT|DBG_FUNC_END, 0,0,0,0,0);
        return (error);
}


/*
 * modwatch system call. user passes in event to modify.
 * if we find it we reset the event bits and que/deque event
 * it needed.
 */
int
modwatch(proc_t p, struct modwatch_args *uap, __unused int *retval)
{
        struct eventreq64 er;
        struct eventreq64 *erp = &er;
        struct eventqelt *evq = NULL;   /* protected by error return */
        int error;
        struct fileproc *fp;
        int flag;

        KERNEL_DEBUG(DBG_MISC_MOD|DBG_FUNC_START, 0,0,0,0,0);

        /*
         * get user's request pkt
         * just need the er_type and er_handle which sit above the
         * problematic er_data (32/64 issue)... so only copy in
         * those 2 fields
         */
        if ((error = copyin(uap->u_req, (caddr_t)erp, sizeof(er.er_type) + sizeof(er.er_handle)))) {
                KERNEL_DEBUG(DBG_MISC_MOD|DBG_FUNC_END, error,0,0,0,0);
                return(error);
        }
        proc_fdlock(p);

        if (erp->er_type != EV_FD) {
                error = EINVAL;
        } else if ((error = fp_lookup(p, erp->er_handle, &fp, 1)) != 0) {
                error = EBADF;
#if SOCKETS
        } else if (fp->f_type == DTYPE_SOCKET) {
                socket_lock((struct socket *)fp->f_data, 1);
                evq = ((struct socket *)fp->f_data)->so_evlist.tqh_first;
#endif /* SOCKETS */
        } else if (fp->f_type == DTYPE_PIPE) {
                PIPE_LOCK((struct pipe *)fp->f_data);
                evq = ((struct pipe *)fp->f_data)->pipe_evlist.tqh_first;
        } else {
                fp_drop(p, erp->er_handle, fp, 1);
                error = EINVAL;
        }

        if (error) {
                proc_fdunlock(p);
                KERNEL_DEBUG(DBG_MISC_MOD|DBG_FUNC_END, error,0,0,0,0);
                return(error);
        }

        if ((uap->u_eventmask == EV_RM) && (fp->f_flags & FP_WAITEVENT)) {
                fp->f_flags &= ~FP_WAITEVENT;
        }
        proc_fdunlock(p);

        // locate event if possible
        for ( ; evq != NULL; evq = evq->ee_slist.tqe_next) {
                if (evq->ee_proc == p)
                        break;
        }
        if (evq == NULL) {
#if SOCKETS
                if (fp->f_type == DTYPE_SOCKET) 
                        socket_unlock((struct socket *)fp->f_data, 1);
                else
#endif /* SOCKETS */
                        PIPE_UNLOCK((struct pipe *)fp->f_data);
                fp_drop(p, erp->er_handle, fp, 0);
                KERNEL_DEBUG(DBG_MISC_MOD|DBG_FUNC_END, EINVAL,0,0,0,0);
                return(EINVAL);
        }
        KERNEL_DEBUG(DBG_MISC_MOD, erp->er_handle,uap->u_eventmask,(uint32_t)evq,0,0);

        if (uap->u_eventmask == EV_RM) {
                EVPROCDEQUE(p, evq);

#if SOCKETS
                if (fp->f_type == DTYPE_SOCKET) {
                        TAILQ_REMOVE(&((struct socket *)fp->f_data)->so_evlist, evq, ee_slist);
                        socket_unlock((struct socket *)fp->f_data, 1);
                } else
#endif /* SOCKETS */
                {
                        TAILQ_REMOVE(&((struct pipe *)fp->f_data)->pipe_evlist, evq, ee_slist);
                        PIPE_UNLOCK((struct pipe *)fp->f_data);
                }
                fp_drop(p, erp->er_handle, fp, 0);
                FREE(evq, M_TEMP);
                KERNEL_DEBUG(DBG_MISC_MOD|DBG_FUNC_END, 0,0,0,0,0);
                return(0);
        }
        switch (uap->u_eventmask & EV_MASK) {
 
        case 0:
                flag = 0;
                break;

        case EV_RE:
        case EV_WR:
        case EV_RE|EV_WR:
                flag = EV_RWBYTES;
                break;

        case EV_EX:
                flag = EV_OOB;
                break;

        case EV_EX|EV_RE:
        case EV_EX|EV_WR:
        case EV_EX|EV_RE|EV_WR:
                flag = EV_OOB|EV_RWBYTES;
                break;

        default:
#if SOCKETS
                if (fp->f_type == DTYPE_SOCKET) 
                        socket_unlock((struct socket *)fp->f_data, 1);
                else 
#endif /* SOCKETS */
                        PIPE_UNLOCK((struct pipe *)fp->f_data);
                fp_drop(p, erp->er_handle, fp, 0);
                KERNEL_DEBUG(DBG_MISC_WATCH|DBG_FUNC_END, EINVAL,0,0,0,0);
                return(EINVAL);
        }
        /*
         * since we're holding the socket/pipe lock, the event
         * cannot go from the unqueued state to the queued state
         * however, it can go from the queued state to the unqueued state
         * since that direction is protected by the proc_lock...
         * so do a quick check for EV_QUEUED w/o holding the proc lock
         * since by far the common case will be NOT EV_QUEUED, this saves
         * us taking the proc_lock the majority of the time
         */
        if (evq->ee_flags & EV_QUEUED) {
                /*
                 * EVPROCDEQUE will recheck the state after it grabs the proc_lock
                 */
                EVPROCDEQUE(p, evq);
        }
        /*
         * while the event is off the proc queue and
         * we're holding the socket/pipe lock
         * it's safe to update these fields...
         */
        evq->ee_req.er_eventbits = 0;
        evq->ee_eventmask = uap->u_eventmask & EV_MASK;

#if SOCKETS
        if (fp->f_type == DTYPE_SOCKET) {
                postevent((struct socket *)fp->f_data, 0, flag);
                socket_unlock((struct socket *)fp->f_data, 1);
        } else
#endif /* SOCKETS */
        {
                postpipeevent((struct pipe *)fp->f_data, flag);
                PIPE_UNLOCK((struct pipe *)fp->f_data);
        }
        fp_drop(p, erp->er_handle, fp, 0);
        KERNEL_DEBUG(DBG_MISC_MOD|DBG_FUNC_END, evq->ee_req.er_handle,evq->ee_eventmask,(uint32_t)fp->f_data,flag,0);
        return(0);
}

/* this routine is called from the close of fd with proc_fdlock held */
int
waitevent_close(struct proc *p, struct fileproc *fp)
{
        struct eventqelt *evq;


        fp->f_flags &= ~FP_WAITEVENT;

#if SOCKETS
        if (fp->f_type == DTYPE_SOCKET) {
                socket_lock((struct socket *)fp->f_data, 1);
                evq = ((struct socket *)fp->f_data)->so_evlist.tqh_first;
        } else
#endif /* SOCKETS */
        if (fp->f_type == DTYPE_PIPE) {
                PIPE_LOCK((struct pipe *)fp->f_data);
                evq = ((struct pipe *)fp->f_data)->pipe_evlist.tqh_first;
        }
        else {
                return(EINVAL);
        }
        proc_fdunlock(p);


        // locate event if possible
        for ( ; evq != NULL; evq = evq->ee_slist.tqe_next) {
                if (evq->ee_proc == p)
                        break;
        }
        if (evq == NULL) {
#if SOCKETS
                if (fp->f_type == DTYPE_SOCKET) 
                        socket_unlock((struct socket *)fp->f_data, 1);
                else 
#endif /* SOCKETS */
                        PIPE_UNLOCK((struct pipe *)fp->f_data);

                proc_fdlock(p);

                return(EINVAL);
        }
        EVPROCDEQUE(p, evq);

#if SOCKETS
        if (fp->f_type == DTYPE_SOCKET) {
                TAILQ_REMOVE(&((struct socket *)fp->f_data)->so_evlist, evq, ee_slist);
                socket_unlock((struct socket *)fp->f_data, 1);
        } else
#endif /* SOCKETS */
        {
                TAILQ_REMOVE(&((struct pipe *)fp->f_data)->pipe_evlist, evq, ee_slist);
                PIPE_UNLOCK((struct pipe *)fp->f_data);
        }
        FREE(evq, M_TEMP);

        proc_fdlock(p);

        return(0);
}


/*
 * gethostuuid
 *
 * Description: Get the host UUID from IOKit and return it to user space.
 *
 * Parameters:  uuid_buf                Pointer to buffer to receive UUID
 *              timeout                 Timespec for timout
 *              spi                             SPI, skip sandbox check (temporary)
 *
 * Returns:     0                       Success
 *              EWOULDBLOCK             Timeout is too short
 *              copyout:EFAULT          Bad user buffer
 *              mac_system_check_info:EPERM             Client not allowed to perform this operation
 *
 * Notes:       A timeout seems redundant, since if it's tolerable to not
 *              have a system UUID in hand, then why ask for one?
 */
int
gethostuuid(struct proc *p, struct gethostuuid_args *uap, __unused int32_t *retval)
{
        kern_return_t kret;
        int error;
        mach_timespec_t mach_ts;        /* for IOKit call */
        __darwin_uuid_t uuid_kern = {}; /* for IOKit call */

        if (!uap->spi) {
#if CONFIG_EMBEDDED
#if CONFIG_MACF
                if ((error = mac_system_check_info(kauth_cred_get(), "hw.uuid")) != 0) {
                        /* EPERM invokes userspace upcall if present */
                        return (error);
                }
#endif
#endif
        }

        /* Convert the 32/64 bit timespec into a mach_timespec_t */
        if ( proc_is64bit(p) ) {
                struct user64_timespec ts;
                error = copyin(uap->timeoutp, &ts, sizeof(ts));
                if (error)
                        return (error);
                mach_ts.tv_sec = ts.tv_sec;
                mach_ts.tv_nsec = ts.tv_nsec;
        } else {
                struct user32_timespec ts;
                error = copyin(uap->timeoutp, &ts, sizeof(ts) );
                if (error)
                        return (error);
                mach_ts.tv_sec = ts.tv_sec;
                mach_ts.tv_nsec = ts.tv_nsec;
        }

        /* Call IOKit with the stack buffer to get the UUID */
        kret = IOBSDGetPlatformUUID(uuid_kern, mach_ts);

        /*
         * If we get it, copy out the data to the user buffer; note that a
         * uuid_t is an array of characters, so this is size invariant for
         * 32 vs. 64 bit.
         */
        if (kret == KERN_SUCCESS) {
                error = copyout(uuid_kern, uap->uuid_buf, sizeof(uuid_kern));
        } else {
                error = EWOULDBLOCK;
        }

        return (error);
}

/*
 * ledger
 *
 * Description: Omnibus system call for ledger operations
 */
int
ledger(struct proc *p, struct ledger_args *args, __unused int32_t *retval)
{
#if !CONFIG_MACF
#pragma unused(p)
#endif
        int rval, pid, len, error;
#ifdef LEDGER_DEBUG
        struct ledger_limit_args lla;
#endif
        task_t task;
        proc_t proc;

        /* Finish copying in the necessary args before taking the proc lock */
        error = 0;
        len = 0;
        if (args->cmd == LEDGER_ENTRY_INFO)
                error = copyin(args->arg3, (char *)&len, sizeof (len));
        else if (args->cmd == LEDGER_TEMPLATE_INFO)
                error = copyin(args->arg2, (char *)&len, sizeof (len));
        else if (args->cmd == LEDGER_LIMIT)
#ifdef LEDGER_DEBUG
                error = copyin(args->arg2, (char *)&lla, sizeof (lla));
#else
                return (EINVAL);
#endif
        else if ((args->cmd < 0) || (args->cmd > LEDGER_MAX_CMD))
                return (EINVAL);

        if (error)
                return (error);
        if (len < 0)
                return (EINVAL);

        rval = 0;
        if (args->cmd != LEDGER_TEMPLATE_INFO) {
                pid = args->arg1;
                proc = proc_find(pid);
                if (proc == NULL)
                        return (ESRCH);

#if CONFIG_MACF
                error = mac_proc_check_ledger(p, proc, args->cmd);
                if (error) {
                        proc_rele(proc);
                        return (error);
                }
#endif

                task = proc->task;
        }
                
        switch (args->cmd) {
#ifdef LEDGER_DEBUG
                case LEDGER_LIMIT: {
                        if (!kauth_cred_issuser(kauth_cred_get()))
                                rval = EPERM;
                        rval = ledger_limit(task, &lla);
                        proc_rele(proc);
                        break;
                }
#endif
                case LEDGER_INFO: {
                        struct ledger_info info = {};

                        rval = ledger_info(task, &info);
                        proc_rele(proc);
                        if (rval == 0)
                                rval = copyout(&info, args->arg2,
                                    sizeof (info));
                        break;
                }

                case LEDGER_ENTRY_INFO: {
                        void *buf;
                        int sz;

                        rval = ledger_get_task_entry_info_multiple(task, &buf, &len);
                        proc_rele(proc);
                        if ((rval == 0) && (len >= 0)) {
                                sz = len * sizeof (struct ledger_entry_info);
                                rval = copyout(buf, args->arg2, sz);
                                kfree(buf, sz);
                        }
                        if (rval == 0)
                                rval = copyout(&len, args->arg3, sizeof (len));
                        break;
                }

                case LEDGER_TEMPLATE_INFO: {
                        void *buf;
                        int sz;

                        rval = ledger_template_info(&buf, &len);
                        if ((rval == 0) && (len >= 0)) {
                                sz = len * sizeof (struct ledger_template_info);
                                rval = copyout(buf, args->arg1, sz);
                                kfree(buf, sz);
                        }
                        if (rval == 0)
                                rval = copyout(&len, args->arg2, sizeof (len));
                        break;
                }

                default:
                        panic("ledger syscall logic error -- command type %d", args->cmd);
                        proc_rele(proc);
                        rval = EINVAL;
        }

        return (rval);
}

int
telemetry(__unused struct proc *p, struct telemetry_args *args, __unused int32_t *retval)
{
        int error = 0;

        switch (args->cmd) {
#if CONFIG_TELEMETRY
        case TELEMETRY_CMD_TIMER_EVENT:
                error = telemetry_timer_event(args->deadline, args->interval, args->leeway);
                break;
        case TELEMETRY_CMD_PMI_SETUP:
                error = telemetry_pmi_setup((enum telemetry_pmi)args->deadline, args->interval);
                break;
#endif /* CONFIG_TELEMETRY */
        case TELEMETRY_CMD_VOUCHER_NAME:
                if (thread_set_voucher_name((mach_port_name_t)args->deadline))
                        error = EINVAL;
                break;

        default:
                error = EINVAL;
                break;
        }

        return (error);
}

#if DEVELOPMENT || DEBUG
#if CONFIG_WAITQ_DEBUG
static uint64_t g_wqset_num = 0;
struct g_wqset {
        queue_chain_t      link;
        struct waitq_set  *wqset;
};

static queue_head_t         g_wqset_list;
static struct waitq_set    *g_waitq_set = NULL;

static inline struct waitq_set *sysctl_get_wqset(int idx)
{
        struct g_wqset *gwqs;

        if (!g_wqset_num)
                queue_init(&g_wqset_list);

        /* don't bother with locks: this is test-only code! */
        qe_foreach_element(gwqs, &g_wqset_list, link) {
                if ((int)(wqset_id(gwqs->wqset) & 0xffffffff) == idx)
                        return gwqs->wqset;
        }

        /* allocate a new one */
        ++g_wqset_num;
        gwqs = (struct g_wqset *)kalloc(sizeof(*gwqs));
        assert(gwqs != NULL);

        gwqs->wqset = waitq_set_alloc(SYNC_POLICY_FIFO|SYNC_POLICY_PREPOST, NULL);
        enqueue_tail(&g_wqset_list, &gwqs->link);
        printf("[WQ]: created new waitq set 0x%llx\n", wqset_id(gwqs->wqset));

        return gwqs->wqset;
}

#define MAX_GLOBAL_TEST_QUEUES 64
static int g_wq_init = 0;
static struct waitq  g_wq[MAX_GLOBAL_TEST_QUEUES];

static inline struct waitq *global_test_waitq(int idx)
{
        if (idx < 0)
                return NULL;

        if (!g_wq_init) {
                g_wq_init = 1;
                for (int i = 0; i < MAX_GLOBAL_TEST_QUEUES; i++)
                        waitq_init(&g_wq[i], SYNC_POLICY_FIFO);
        }

        return &g_wq[idx % MAX_GLOBAL_TEST_QUEUES];
}

static int sysctl_waitq_wakeup_one SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
        int error;
        int index;
        struct waitq *waitq;
        kern_return_t kr;
        int64_t event64 = 0;

        error = SYSCTL_IN(req, &event64, sizeof(event64));
        if (error)
                return error;

        if (!req->newptr)
                return SYSCTL_OUT(req, &event64, sizeof(event64));

        if (event64 < 0) {
                index = (int)((-event64) & 0xffffffff);
                waitq = wqset_waitq(sysctl_get_wqset(index));
                index = -index;
        } else {
                index = (int)event64;
                waitq = global_test_waitq(index);
        }

        event64 = 0;

        printf("[WQ]: Waking one thread on waitq [%d] event:0x%llx\n",
               index, event64);
        kr = waitq_wakeup64_one(waitq, (event64_t)event64, THREAD_AWAKENED,
                                WAITQ_ALL_PRIORITIES);
        printf("[WQ]: \tkr=%d\n", kr);

        return SYSCTL_OUT(req, &kr, sizeof(kr));
}
SYSCTL_PROC(_kern, OID_AUTO, waitq_wakeup_one, CTLTYPE_QUAD | CTLFLAG_RW | CTLFLAG_LOCKED,
            0, 0, sysctl_waitq_wakeup_one, "Q", "wakeup one thread waiting on given event");


static int sysctl_waitq_wakeup_all SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
        int error;
        int index;
        struct waitq *waitq;
        kern_return_t kr;
        int64_t event64 = 0;

        error = SYSCTL_IN(req, &event64, sizeof(event64));
        if (error)
                return error;

        if (!req->newptr)
                return SYSCTL_OUT(req, &event64, sizeof(event64));

        if (event64 < 0) {
                index = (int)((-event64) & 0xffffffff);
                waitq = wqset_waitq(sysctl_get_wqset(index));
                index = -index;
        } else {
                index = (int)event64;
                waitq = global_test_waitq(index);
        }

        event64 = 0;

        printf("[WQ]: Waking all threads on waitq [%d] event:0x%llx\n",
               index, event64);
        kr = waitq_wakeup64_all(waitq, (event64_t)event64,
                                THREAD_AWAKENED, WAITQ_ALL_PRIORITIES);
        printf("[WQ]: \tkr=%d\n", kr);

        return SYSCTL_OUT(req, &kr, sizeof(kr));
}
SYSCTL_PROC(_kern, OID_AUTO, waitq_wakeup_all, CTLTYPE_QUAD | CTLFLAG_RW | CTLFLAG_LOCKED,
            0, 0, sysctl_waitq_wakeup_all, "Q", "wakeup all threads waiting on given event");


static int sysctl_waitq_wait SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
        int error;
        int index;
        struct waitq *waitq;
        kern_return_t kr;
        int64_t event64 = 0;

        error = SYSCTL_IN(req, &event64, sizeof(event64));
        if (error)
                return error;

        if (!req->newptr)
                return SYSCTL_OUT(req, &event64, sizeof(event64));

        if (event64 < 0) {
                index = (int)((-event64) & 0xffffffff);
                waitq = wqset_waitq(sysctl_get_wqset(index));
                index = -index;
        } else {
                index = (int)event64;
                waitq = global_test_waitq(index);
        }

        event64 = 0;

        printf("[WQ]: Current thread waiting on waitq [%d] event:0x%llx\n",
               index, event64);
        kr = waitq_assert_wait64(waitq, (event64_t)event64, THREAD_INTERRUPTIBLE, 0);
        if (kr == THREAD_WAITING)
                thread_block(THREAD_CONTINUE_NULL);
        printf("[WQ]: \tWoke Up: kr=%d\n", kr);

        return SYSCTL_OUT(req, &kr, sizeof(kr));
}
SYSCTL_PROC(_kern, OID_AUTO, waitq_wait, CTLTYPE_QUAD | CTLFLAG_RW | CTLFLAG_LOCKED,
            0, 0, sysctl_waitq_wait, "Q", "start waiting on given event");


static int sysctl_wqset_select SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
        int error;
        struct waitq_set *wqset;
        uint64_t event64 = 0;

        error = SYSCTL_IN(req, &event64, sizeof(event64));
        if (error)
                return error;

        if (!req->newptr)
                goto out;

        wqset = sysctl_get_wqset((int)(event64 & 0xffffffff));
        g_waitq_set = wqset;

        event64 = wqset_id(wqset);
        printf("[WQ]: selected wqset 0x%llx\n", event64);

out:
        if (g_waitq_set)
                event64 = wqset_id(g_waitq_set);
        else
                event64 = (uint64_t)(-1);

        return SYSCTL_OUT(req, &event64, sizeof(event64));
}
SYSCTL_PROC(_kern, OID_AUTO, wqset_select, CTLTYPE_QUAD | CTLFLAG_RW | CTLFLAG_LOCKED,
            0, 0, sysctl_wqset_select, "Q", "select/create a global waitq set");


static int sysctl_waitq_link SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
        int error;
        int index;
        struct waitq *waitq;
        struct waitq_set *wqset;
        kern_return_t kr;
        uint64_t reserved_link = 0;
        int64_t event64 = 0;

        error = SYSCTL_IN(req, &event64, sizeof(event64));
        if (error)
                return error;

        if (!req->newptr)
                return SYSCTL_OUT(req, &event64, sizeof(event64));

        if (!g_waitq_set)
                g_waitq_set = sysctl_get_wqset(1);
        wqset = g_waitq_set;

        if (event64 < 0) {
                struct waitq_set *tmp;
                index = (int)((-event64) & 0xffffffff);
                tmp = sysctl_get_wqset(index);
                if (tmp == wqset)
                        goto out;
                waitq = wqset_waitq(tmp);
                index = -index;
        } else {
                index = (int)event64;
                waitq = global_test_waitq(index);
        }

        printf("[WQ]: linking waitq [%d] to global wqset (0x%llx)\n",
               index, wqset_id(wqset));
        reserved_link = waitq_link_reserve(waitq);
        kr = waitq_link(waitq, wqset, WAITQ_SHOULD_LOCK, &reserved_link);
        waitq_link_release(reserved_link);

        printf("[WQ]: \tkr=%d\n", kr);

out:
        return SYSCTL_OUT(req, &kr, sizeof(kr));
}
SYSCTL_PROC(_kern, OID_AUTO, waitq_link, CTLTYPE_QUAD | CTLFLAG_RW | CTLFLAG_LOCKED,
            0, 0, sysctl_waitq_link, "Q", "link global waitq to test waitq set");


static int sysctl_waitq_unlink SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
        int error;
        int index;
        struct waitq *waitq;
        struct waitq_set *wqset;
        kern_return_t kr;
        uint64_t event64 = 0;

        error = SYSCTL_IN(req, &event64, sizeof(event64));
        if (error)
                return error;

        if (!req->newptr)
                return SYSCTL_OUT(req, &event64, sizeof(event64));

        if (!g_waitq_set)
                g_waitq_set = sysctl_get_wqset(1);
        wqset = g_waitq_set;

        index = (int)event64;
        waitq = global_test_waitq(index);

        printf("[WQ]: unlinking waitq [%d] from global wqset (0x%llx)\n",
               index, wqset_id(wqset));

        kr = waitq_unlink(waitq, wqset);
        printf("[WQ]: \tkr=%d\n", kr);

        return SYSCTL_OUT(req, &kr, sizeof(kr));
}
SYSCTL_PROC(_kern, OID_AUTO, waitq_unlink, CTLTYPE_QUAD | CTLFLAG_RW | CTLFLAG_LOCKED,
            0, 0, sysctl_waitq_unlink, "Q", "unlink global waitq from test waitq set");


static int sysctl_waitq_clear_prepost SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
        struct waitq *waitq;
        uint64_t event64 = 0;
        int error, index;

        error = SYSCTL_IN(req, &event64, sizeof(event64));
        if (error)
                return error;

        if (!req->newptr)
                return SYSCTL_OUT(req, &event64, sizeof(event64));

        index = (int)event64;
        waitq = global_test_waitq(index);

        printf("[WQ]: clearing prepost on waitq [%d]\n", index);
        waitq_clear_prepost(waitq);

        return SYSCTL_OUT(req, &event64, sizeof(event64));
}
SYSCTL_PROC(_kern, OID_AUTO, waitq_clear_prepost, CTLTYPE_QUAD | CTLFLAG_RW | CTLFLAG_LOCKED,
            0, 0, sysctl_waitq_clear_prepost, "Q", "clear prepost on given waitq");


static int sysctl_wqset_unlink_all SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
        int error;
        struct waitq_set *wqset;
        kern_return_t kr;
        uint64_t event64 = 0;

        error = SYSCTL_IN(req, &event64, sizeof(event64));
        if (error)
                return error;

        if (!req->newptr)
                return SYSCTL_OUT(req, &event64, sizeof(event64));

        if (!g_waitq_set)
                g_waitq_set = sysctl_get_wqset(1);
        wqset = g_waitq_set;

        printf("[WQ]: unlinking all queues from global wqset (0x%llx)\n",
               wqset_id(wqset));

        kr = waitq_set_unlink_all(wqset);
        printf("[WQ]: \tkr=%d\n", kr);

        return SYSCTL_OUT(req, &kr, sizeof(kr));
}
SYSCTL_PROC(_kern, OID_AUTO, wqset_unlink_all, CTLTYPE_QUAD | CTLFLAG_RW | CTLFLAG_LOCKED,
            0, 0, sysctl_wqset_unlink_all, "Q", "unlink all queues from test waitq set");


static int sysctl_wqset_clear_preposts SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
        struct waitq_set *wqset = NULL;
        uint64_t event64 = 0;
        int error, index;

        error = SYSCTL_IN(req, &event64, sizeof(event64));
        if (error)
                return error;

        if (!req->newptr)
                goto out;

        index = (int)((event64) & 0xffffffff);
        wqset = sysctl_get_wqset(index);
        assert(wqset != NULL);

        printf("[WQ]: clearing preposts on wqset 0x%llx\n", wqset_id(wqset));
        waitq_set_clear_preposts(wqset);

out:
        if (wqset)
                event64 = wqset_id(wqset);
        else
                event64 = (uint64_t)(-1);

        return SYSCTL_OUT(req, &event64, sizeof(event64));
}
SYSCTL_PROC(_kern, OID_AUTO, wqset_clear_preposts, CTLTYPE_QUAD | CTLFLAG_RW | CTLFLAG_LOCKED,
            0, 0, sysctl_wqset_clear_preposts, "Q", "clear preposts on given waitq set");

#endif /* CONFIG_WAITQ_DEBUG */

static int
sysctl_waitq_set_nelem SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
        int nelem;

        /* Read only  */
        if (req->newptr != USER_ADDR_NULL)
                return (EPERM);

        nelem = sysctl_helper_waitq_set_nelem();

        return SYSCTL_OUT(req, &nelem, sizeof(nelem));
}

SYSCTL_PROC(_kern, OID_AUTO, n_ltable_entries, CTLFLAG_RD | CTLFLAG_LOCKED,
                0, 0, sysctl_waitq_set_nelem, "I", "ltable elementis currently used");


#endif /* DEVELOPMENT || DEBUG */