xnu-124.8.tar.gz

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

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/* Copyright (c) 1995 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
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/filedesc.h>
#include <sys/ioctl.h>
#include <sys/file.h>
#include <sys/proc.h>
#include <sys/socketvar.h>
#include <sys/uio.h>
#include <sys/kernel.h>
#include <sys/stat.h>
#include <sys/malloc.h>

#if KTRACE
#include <sys/ktrace.h>
#endif

#include <sys/mount.h>
#include <sys/protosw.h>
#include <sys/ev.h>
#include <sys/user.h>
#include <sys/kdebug.h>
#include <kern/assert.h>
#include <kern/thread_act.h>

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

/*
 * Read system call.
 */
struct read_args {
        int fd;
        char *cbuf;
        u_int nbyte;
};
/* ARGSUSED */
read(p, uap, retval)
        struct proc *p;
        register struct read_args *uap;
        register_t *retval;
{
        struct uio auio;
        struct iovec aiov;

        aiov.iov_base = (caddr_t)uap->cbuf;
        aiov.iov_len = uap->nbyte;
        auio.uio_iov = &aiov;
        auio.uio_iovcnt = 1;
        auio.uio_rw = UIO_READ;
        return (rwuio(p, uap->fd, &auio, UIO_READ, retval));    
}

struct readv_args {
        int fd;
        struct iovec *iovp;
        u_int iovcnt;
};
readv(p, uap, retval)
        struct proc *p;
        register struct readv_args *uap;
        int *retval;
{
        struct uio auio;
        register struct iovec *iov;
        int error;
        struct iovec aiov[UIO_SMALLIOV];

        if (uap->iovcnt > UIO_SMALLIOV) {
                if (uap->iovcnt > UIO_MAXIOV)
                        return (EINVAL);        
                if ((iov = (struct iovec *)
                            kalloc(sizeof(struct iovec) * (uap->iovcnt))) == 0)
                        return (ENOMEM);
        } else
                iov = aiov;
        auio.uio_iov = iov;
        auio.uio_iovcnt = uap->iovcnt;
        auio.uio_rw = UIO_READ;
        error = copyin((caddr_t)uap->iovp, (caddr_t)iov,
            uap->iovcnt * sizeof (struct iovec));
        if (!error)
                error = rwuio(p, uap->fd, &auio, UIO_READ, retval);
        if (uap->iovcnt > UIO_SMALLIOV)
                kfree(iov, sizeof(struct iovec)*uap->iovcnt);
        return (error);
}

/*
 * Write system call
 */
struct write_args {
        int fd;
        char *cbuf;
        u_int nbyte;
};
write(p, uap, retval)
        struct proc *p;
        register struct write_args *uap;
        int *retval;
{
        struct uio auio;
        struct iovec aiov;

        aiov.iov_base = uap->cbuf;
        aiov.iov_len = uap->nbyte;
        auio.uio_iov = &aiov;
        auio.uio_iovcnt = 1;
        auio.uio_rw = UIO_WRITE;
        return (rwuio(p, uap->fd, &auio, UIO_WRITE, retval));
}

struct writev_args {
        int fd;
        struct iovec *iovp;
        u_int iovcnt;
};
writev(p, uap, retval)
        struct proc *p;
        register struct writev_args *uap;
        int *retval;
{
        struct uio auio;
        register struct iovec *iov;
        int error;
        struct iovec aiov[UIO_SMALLIOV];

        if (uap->iovcnt > UIO_SMALLIOV) {
                if (uap->iovcnt > UIO_MAXIOV)
                        return (EINVAL);        
                if ((iov = (struct iovec *)
                            kalloc(sizeof(struct iovec) * (uap->iovcnt))) == 0)
                        return (ENOMEM);
        } else
                iov = aiov;
        auio.uio_iov = iov;
        auio.uio_iovcnt = uap->iovcnt;
        auio.uio_rw = UIO_WRITE;
        error = copyin((caddr_t)uap->iovp, (caddr_t)iov,
            uap->iovcnt * sizeof (struct iovec));
        if (!error)
                error = rwuio(p, uap->fd, &auio, UIO_WRITE, retval);
        if (uap->iovcnt > UIO_SMALLIOV)
                kfree(iov, sizeof(struct iovec)*uap->iovcnt);
        return (error);
}

rwuio(p, fdes, uio, rw, retval)
        struct proc *p;
        int fdes;
        register struct uio *uio;
        enum uio_rw rw;
        int *retval;
{
        struct file *fp;
        register struct iovec *iov;
        int i, count, flag, error;

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

        if ((fp->f_flag&(rw==UIO_READ ? FREAD : FWRITE)) == 0) {
                return(EBADF);
        }
        uio->uio_resid = 0;
        uio->uio_segflg = UIO_USERSPACE;
        uio->uio_procp = p;
        iov = uio->uio_iov;
        for (i = 0; i < uio->uio_iovcnt; i++) {
                if (iov->iov_len < 0) {
                        return(EINVAL);
                }
                uio->uio_resid += iov->iov_len;
                if (uio->uio_resid < 0) {
                        return(EINVAL);
                }
                iov++;
        }
        count = uio->uio_resid;
        if (rw == UIO_READ) {
                if (error = (*fp->f_ops->fo_read)(fp, uio, fp->f_cred))
                                if (uio->uio_resid != count && (error == ERESTART ||
                                        error == EINTR || error == EWOULDBLOCK))
                                                error = 0;
        } else {
                if (error = (*fp->f_ops->fo_write)(fp, uio, fp->f_cred)) {
                        if (uio->uio_resid != count && (error == ERESTART ||
                        error == EINTR || error == EWOULDBLOCK))
                                error = 0;
                        if (error == EPIPE)
                                psignal(p, SIGPIPE);
                }
        }
        *retval = count - uio->uio_resid;
        return(error);
}

/*
 * Ioctl system call
 */
struct ioctl_args {
        int fd;
        u_long com;
        caddr_t data;
};
/* ARGSUSED */
ioctl(p, uap, retval)
        struct proc *p;
        register struct ioctl_args *uap;
        register_t *retval;
{
        struct file *fp;
        register u_long com;
        register int error;
        register u_int size;
        caddr_t data, memp;
        int tmp;
#define STK_PARAMS      128
        char stkbuf[STK_PARAMS];

        if (error = fdgetf(p, uap->fd, &fp))
                return (error);

        if ((fp->f_flag & (FREAD | FWRITE)) == 0)
                return (EBADF);
                
        /*### LD 6/11/97 Hack Alert: this is to get AppleTalk to work
         * while implementing an ATioctl system call
         */
#if NETAT
        {
                extern int appletalk_inited;

                if (appletalk_inited && ((uap->com & 0x0000FFFF) == 0xff99)) {
#ifdef APPLETALK_DEBUG
                        kprintf("ioctl: special AppleTalk \n");
#endif
                        error = (*fp->f_ops->fo_ioctl)(fp, uap->com, uap->data, p);
                        return(error);
                }
        }

#endif /* NETAT */


        switch (com = uap->com) {
        case FIONCLEX:
                *fdflags(p, uap->fd) &= ~UF_EXCLOSE;
                return (0);
        case FIOCLEX:
                *fdflags(p, uap->fd) |= UF_EXCLOSE;
                return (0);
        }

        /*
         * 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);
        memp = NULL;
        if (size > sizeof (stkbuf)) {
                if ((memp = (caddr_t)kalloc(size)) == 0)
                        return(ENOMEM);
                data = memp;
        } else
                data = stkbuf;
        if (com&IOC_IN) {
                if (size) {
                        error = copyin(uap->data, data, (u_int)size);
                        if (error) {
                                if (memp)
                                        kfree(memp, size);
                                return (error);
                        }
                } else
                        *(caddr_t *)data = uap->data;
        } else if ((com&IOC_OUT) && size)
                /*
                 * Zero the buffer so the user always
                 * gets back something deterministic.
                 */
                bzero(data, size);
        else if (com&IOC_VOID)
                *(caddr_t *)data = uap->data;

        switch (com) {

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

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

        case FIOSETOWN:
                tmp = *(int *)data;
                if (fp->f_type == DTYPE_SOCKET) {
                        ((struct socket *)fp->f_data)->so_pgid = tmp;
                        error = 0;
                        break;
                }
                if (tmp <= 0) {
                        tmp = -tmp;
                } else {
                        struct proc *p1 = pfind(tmp);
                        if (p1 == 0) {
                                error = ESRCH;
                                break;
                        }
                        tmp = p1->p_pgrp->pg_id;
                }
                error = (*fp->f_ops->fo_ioctl)
                        (fp, (int)TIOCSPGRP, (caddr_t)&tmp, p);
                break;

        case FIOGETOWN:
                if (fp->f_type == DTYPE_SOCKET) {
                        error = 0;
                        *(int *)data = ((struct socket *)fp->f_data)->so_pgid;
                        break;
                }
                error = (*fp->f_ops->fo_ioctl)(fp, TIOCGPGRP, data, p);
                *(int *)data = -*(int *)data;
                break;

        default:
                error = (*fp->f_ops->fo_ioctl)(fp, com, data, p);
                /*
                 * Copy any data to user, size was
                 * already set and checked above.
                 */
                if (error == 0 && (com&IOC_OUT) && size)
                        error = copyout(data, uap->data, (u_int)size);
                break;
        }
        if (memp)
                kfree(memp, size);
        return (error);
}


int     selwait, nselcoll;

/*
 * Select system call.
 */
struct select_args {
        int nd;
        u_int32_t *in;
        u_int32_t *ou;
        u_int32_t *ex;
        struct timeval *tv;
};

extern int selcontinue(int error);
static int selscan(     struct proc *p, u_int32_t *ibits, u_int32_t *obits,
                                        int nfd, register_t *retval);

select(p, uap, retval)
        register struct proc *p;
        register struct select_args *uap;
        register_t *retval;
{
        int s, error = 0, timo;
        u_int ni, nw;
        thread_act_t th_act;
        struct uthread  *uth;
        struct _select *sel;
        int needzerofill = 1;

        th_act = current_act();
        uth = get_bsdthread_info(th_act);
        sel = &uth->uu_state.ss_select;
        retval = (int *)get_bsduthreadrval(th_act);
        *retval = 0;

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

        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 this is the first select by the thread 
         * allocate the space for bits.
         */
        if (sel->nbytes == 0) {
                sel->nbytes = 3 * ni;
                MALLOC(sel->ibits, u_int32_t *, sel->nbytes, M_TEMP, M_WAITOK);
                MALLOC(sel->obits, u_int32_t *, sel->nbytes, M_TEMP, M_WAITOK);
                bzero((caddr_t)sel->ibits, sel->nbytes);
                bzero((caddr_t)sel->obits, sel->nbytes);
                needzerofill = 0;
        }

        /*
         * if the previously allocated space for the bits
         * is smaller than what is requested. Reallocate.
         */
        if (sel->nbytes < (3 * ni)) {
                sel->nbytes = (3 * ni);
                FREE(sel->ibits, M_TEMP);
                FREE(sel->obits, M_TEMP);
                MALLOC(sel->ibits, u_int32_t *, sel->nbytes, M_TEMP, M_WAITOK);
                MALLOC(sel->obits, u_int32_t *, sel->nbytes, M_TEMP, M_WAITOK);
                bzero((caddr_t)sel->ibits, sel->nbytes);
                bzero((caddr_t)sel->obits, sel->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((caddr_t)uap->name, \
                        (caddr_t)&sel->ibits[(x) * nw], ni))) \
                        goto continuation; \
        } while (0)

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

        if (uap->tv) {
                error = copyin((caddr_t)uap->tv, (caddr_t)&sel->atv,
                        sizeof (sel->atv));
                if (error)
                        goto continuation;
                if (itimerfix(&sel->atv)) {
                        error = EINVAL;
                        goto continuation;
                }
                s = splhigh();
                timeradd(&sel->atv, &time, &sel->atv);
                timo = hzto(&sel->atv);
                splx(s);
        } else
                timo = 0;
        sel->poll = timo;
continuation:
        selcontinue(error);
}

int
selcontinue(error)
{
        int s, ncoll, timo;
        u_int ni, nw;
        thread_act_t th_act;
        struct uthread  *uth;
        struct proc *p;
        struct select_args *uap;
        int *retval;
        struct _select *sel;

        p = current_proc();
        th_act = current_act();
        uap = (struct select_args *)get_bsduthreadarg(th_act);
        retval = (int *)get_bsduthreadrval(th_act);
        uth = get_bsdthread_info(th_act);
        sel = &uth->uu_state.ss_select;

retry:
        if (error != 0)
          goto done;
        ncoll = nselcoll;
        p->p_flag |= P_SELECT;
        error = selscan(p, sel->ibits, sel->obits, uap->nd, retval);
        if (error || *retval)
                goto done;
        s = splhigh();
        /* this should be timercmp(&time, &atv, >=) */
        if (uap->tv && (time.tv_sec > sel->atv.tv_sec ||
            time.tv_sec == sel->atv.tv_sec && time.tv_usec >= sel->atv.tv_usec)) {
                splx(s);
                goto done;
        }
        /*
         * To effect a poll, the timeout argument should be
         * non-nil, pointing to a zero-valued timeval structure.
         */
        timo = sel->poll;

        if (uap->tv && (timo == 0)) {
                splx(s);
                goto done;
        }
        if ((p->p_flag & P_SELECT) == 0 || nselcoll != ncoll) {
                splx(s);
                goto retry;
        }
        p->p_flag &= ~P_SELECT;

#if 1 /* Use Continuations */
        error = tsleep0((caddr_t)&selwait, PSOCK | PCATCH, "select", timo, selcontinue);
        /* NOTREACHED */
#else
        error = tsleep((caddr_t)&selwait, PSOCK | PCATCH, "select", timo);
#endif
        splx(s);
        if (error == 0)
                goto retry;
done:
        p->p_flag &= ~P_SELECT;
        /* 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], \
                        (caddr_t)uap->name, ni))) \
                        error = error2; \
        } while (0)

        if (error == 0) {
                int error2;

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

#if defined (__i386__)
        return(error);
#else
        unix_syscall_return(error);
#endif
}

static int
selscan(p, ibits, obits, nfd, retval)
        struct proc *p;
        u_int32_t *ibits, *obits;
        int nfd;
        register_t *retval;
{
        register struct filedesc *fdp = p->p_fd;
        register int msk, i, j, fd;
        register u_int32_t bits;
        struct file *fp;
        int n = 0;
        static int flag[3] = { FREAD, FWRITE, 0 };
        u_int32_t *iptr, *optr;
        u_int nw;

        /*
         * 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);
        }

        nw = howmany(nfd, NFDBITS);

        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);
                                fp = fdp->fd_ofiles[fd];
                                if (fp == NULL ||
                                        (fdp->fd_ofileflags[fd] & UF_RESERVED))
                                        return (EBADF);
                                if (fp->f_ops && (*fp->f_ops->fo_select)(fp, flag[msk], p)) {
                                        optr[fd/NFDBITS] |= (1 << (fd % NFDBITS));
                                        n++;
                                }
                        }
                }
        }
        *retval = n;
        return (0);
}

/*ARGSUSED*/
seltrue(dev, flag, p)
        dev_t dev;
        int flag;
        struct proc *p;
{

        return (1);
}

/*
 * Record a select request.
 */
void
selrecord(selector, sip)
        struct proc *selector;
        struct selinfo *sip;
{
        int             oldpri = splhigh();
        thread_t        my_thread = current_thread();
        thread_t        selthread;

        selthread = sip->si_thread;
        
        if (selthread == my_thread) {
                splx(oldpri);
                return;
        }
        
        if (selthread && is_thread_active(selthread) &&
                get_thread_waitevent(selthread) == (caddr_t)&selwait) {
                sip->si_flags |= SI_COLL;
                splx(oldpri);
        } else {
                sip->si_thread = my_thread;
                splx(oldpri);
                act_reference(current_act());
                if (selthread) {
                        act_deallocate(getact_thread(selthread));
                }
        }

        return;
}

void
selwakeup(sip)
        register struct selinfo *sip;
{
        register thread_t       the_thread = (thread_t)sip->si_thread;
        int oldpri;
        struct proc *p;
        thread_act_t th_act;
        
        if (the_thread == 0)
                return;

        if (sip->si_flags & SI_COLL) {
                nselcoll++;
                sip->si_flags &= ~SI_COLL;
                wakeup((caddr_t)&selwait);
        }
        
        oldpri = splhigh();

        th_act = (thread_act_t)getact_thread(the_thread);

        if (is_thread_active(the_thread)) {
                if (get_thread_waitevent(the_thread) == &selwait)
                        clear_wait(the_thread, THREAD_AWAKENED);
                if (p = current_proc())
                        p->p_flag &= ~P_SELECT;
        }
        
        /* th_act = (thread_act_t)getact_thread(the_thread); */

        act_deallocate(th_act);
        
        sip->si_thread = 0;
        
        splx(oldpri);
}

void 
selthreadclear(sip)
        register struct selinfo *sip;
{
        thread_act_t th_act;

        if (sip->si_thread) {
                th_act = (thread_act_t)getact_thread(sip->si_thread);
                act_deallocate(th_act);
        }
}


extern struct eventqelt *evprocdeque(struct proc *p, struct eventqelt *eqp);

/*
 * called upon socket close. deque and free all events for
 * the socket
 */
evsofree(struct socket *sp)
{
  struct eventqelt *eqp, *next;

  if (sp == NULL) return;

  for (eqp = sp->so_evlist.tqh_first; eqp != NULL; eqp = next) {
    next = eqp->ee_slist.tqe_next;
    evprocdeque(eqp->ee_proc, eqp); // remove from proc q if there
    TAILQ_REMOVE(&sp->so_evlist, eqp, ee_slist); // remove from socket q
    FREE(eqp, M_TEMP);
  }
}


#define DBG_EVENT 0x10

#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)


/*
 * enque this event if it's not already queued. wakeup
   the proc if we do queue this event to it.
 */
evprocenque(struct eventqelt *eqp)
{
  struct proc *p;

  assert(eqp);
  KERNEL_DEBUG(DBG_MISC_ENQUEUE|DBG_FUNC_START, eqp, eqp->ee_flags, eqp->ee_eventmask,0,0);
  if (eqp->ee_flags & EV_QUEUED) {
    KERNEL_DEBUG(DBG_MISC_ENQUEUE|DBG_FUNC_END, 0,0,0,0,0);
    return;
  }
  eqp->ee_flags |= EV_QUEUED;
  eqp->ee_eventmask = 0;  // disarm
  p = eqp->ee_proc;
  TAILQ_INSERT_TAIL(&p->p_evlist, eqp, ee_plist);
  KERNEL_DEBUG(DBG_MISC_EWAKEUP,0,0,0,eqp,0);
  wakeup(&p->p_evlist);
  KERNEL_DEBUG(DBG_MISC_ENQUEUE|DBG_FUNC_END, 0,0,0,0,0);
}

/*
 * given either a sockbuf or a socket run down the
 * event list and queue ready events found
 */
postevent(struct socket *sp, struct sockbuf *sb, int event)
{
  int mask;
  struct eventqelt *evq;
  register struct tcpcb *tp;

  if (sb) sp = sb->sb_so;
  if (!sp || sp->so_evlist.tqh_first == NULL) return;

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

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

    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_RWBYTES:
    case EV_OOB:
    case EV_RWBYTES|EV_OOB:
      if (event & EV_OOB) {
      if ((evq->ee_eventmask & EV_EX)) {
        if (sp->so_oobmark || ((sp->so_state & SS_RCVATMARK))) {
          mask |= EV_EX|EV_OOB;
        }
      }
      }
      if (event & EV_RWBYTES) {
      if ((evq->ee_eventmask & EV_RE) && soreadable(sp)) {
        if ((sp->so_type == SOCK_STREAM) && (sp->so_error == ECONNREFUSED) ||
            (sp->so_error == ECONNRESET)) {
          if ((sp->so_pcb == 0) ||
              !(tp = sototcpcb(sp)) ||
              (tp->t_state == TCPS_CLOSED)) {
            mask |= EV_RE|EV_RESET;
            break;
          }
        }
        if (sp->so_state & SS_CANTRCVMORE) {
          mask |= EV_RE|EV_FIN;
          evq->ee_req.er_rcnt = sp->so_rcv.sb_cc;
          break;
        }
        mask |= EV_RE;
        evq->ee_req.er_rcnt = sp->so_rcv.sb_cc;
      }

      if ((evq->ee_eventmask & EV_WR) && sowriteable(sp)) {
        if ((sp->so_type == SOCK_STREAM) &&(sp->so_error == ECONNREFUSED) ||
            (sp->so_error == ECONNRESET)) {
          if ((sp->so_pcb == 0) ||
              !(tp = sototcpcb(sp)) ||
              (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)) {
        evq->ee_req.er_rcnt = sp->so_qlen + 1;  // incl this one
        mask |= EV_RE|EV_RCONN;
      }
      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:
      return;
    } /* switch */

    if (mask) {
      evq->ee_req.er_eventbits |= mask;
      KERNEL_DEBUG(DBG_MISC_POST, evq, evq->ee_req.er_eventbits, mask,0,0);
      evprocenque(evq);
    }
  }
  KERNEL_DEBUG(DBG_MISC_POST|DBG_FUNC_END, 0,0,0,0,0);
}

/*
 * remove and return the first event (eqp=NULL) or a specific
 * event, or return NULL if no events found
 */
struct eventqelt *
evprocdeque(struct proc *p, struct eventqelt *eqp)
{
  
  KERNEL_DEBUG(DBG_MISC_DEQUEUE|DBG_FUNC_START,p,eqp,0,0,0);

  if (eqp && ((eqp->ee_flags & EV_QUEUED) == NULL)) {
    KERNEL_DEBUG(DBG_MISC_DEQUEUE|DBG_FUNC_END,0,0,0,0,0);
    return(NULL);
  }
  if (p->p_evlist.tqh_first == NULL) {
    KERNEL_DEBUG(DBG_MISC_DEQUEUE|DBG_FUNC_END,0,0,0,0,0);
    return(NULL);
  }
  if (eqp == NULL) {  // remove first
    eqp = p->p_evlist.tqh_first;
  }
  TAILQ_REMOVE(&p->p_evlist, eqp, ee_plist);
  eqp->ee_flags &= ~EV_QUEUED;
  KERNEL_DEBUG(DBG_MISC_DEQUEUE|DBG_FUNC_END,eqp,0,0,0,0);
  return(eqp);
}

struct evwatch_args {
  struct eventreq  *u_req;
  int               u_eventmask;
};


/*
 * 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?
 */
int
watchevent(p, uap, retval)
     struct proc *p;
     struct evwatch_args *uap;
     register_t *retval;
{
  struct eventqelt *eqp = (struct eventqelt *)0;
  struct eventqelt *np;
  struct eventreq *erp;
  struct file *fp;
  struct socket *sp;
  int error;

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

  // get a qelt and fill with users req
  MALLOC(eqp, struct eventqelt *, sizeof(struct eventqelt), M_TEMP, M_WAITOK);
  if (!eqp) panic("can't MALLOC eqp");
  erp = &eqp->ee_req;
  // get users request pkt
  if (error = copyin((caddr_t)uap->u_req, (caddr_t)erp,
                     sizeof(struct eventreq))) {
    FREE(eqp, 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,eqp,0,0);
  // validate, freeing qelt if errors
  error = 0;
  if (erp->er_type != EV_FD) {
    error = EINVAL;
  } else  if (erp->er_handle < 0) {
    error = EBADF;
  } else  if (erp->er_handle > p->p_fd->fd_nfiles) {
    error = EBADF;
  } else if ((fp = *fdfile(p, erp->er_handle)) == NULL) {
    error = EBADF;
  } else if (fp->f_type != DTYPE_SOCKET) {
    error = EINVAL;
  }
  if (error) {
    FREE(eqp,M_TEMP);
    KERNEL_DEBUG(DBG_MISC_WATCH|DBG_FUNC_END, error,0,0,0,0);
    return(error);
  }

  erp->er_rcnt = erp->er_wcnt = erp->er_eventbits = 0;
  eqp->ee_proc = p;
  eqp->ee_eventmask = uap->u_eventmask & EV_MASK;
  eqp->ee_flags = 0;

  sp = (struct socket *)fp->f_data;
  assert(sp != NULL);

  // only allow one watch per file per proc
  for (np = sp->so_evlist.tqh_first; np != NULL; np = np->ee_slist.tqe_next) {
    if (np->ee_proc == p) {
      FREE(eqp,M_TEMP);
      KERNEL_DEBUG(DBG_MISC_WATCH|DBG_FUNC_END, EINVAL,0,0,0,0);
      return(EINVAL);
    }
  }

  TAILQ_INSERT_TAIL(&sp->so_evlist, eqp, ee_slist);
  postevent(sp, 0, EV_RWBYTES); // catch existing events
  KERNEL_DEBUG(DBG_MISC_WATCH|DBG_FUNC_END, 0,0,0,0,0);
  return(0);
}

struct evwait_args {
  struct eventreq *u_req;
  struct timeval *tv;
};

/*
 * 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 poll mode (tv=NULL);
 */
int
waitevent(p, uap, retval)
     struct proc *p;
     struct evwait_args *uap;
     register_t *retval;
{
  int error = 0;
  struct eventqelt *eqp;
  int timo;
  struct timeval atv;
  int s;

        if (uap->tv) {
                error = copyin((caddr_t)uap->tv, (caddr_t)&atv,
                        sizeof (atv));
                if (error)
                        return(error);
                if (itimerfix(&atv)) {
                        error = EINVAL;
                        return(error);
                }
                s = splhigh();
                timeradd(&atv, &time, &atv);
                timo = hzto(&atv);
                splx(s);
        } else
                timo = 0;

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

retry:
  s = splhigh();
  if ((eqp = evprocdeque(p,NULL)) != NULL) {
    splx(s);
    error = copyout((caddr_t)&eqp->ee_req, (caddr_t)uap->u_req,
                    sizeof(struct eventreq));
    KERNEL_DEBUG(DBG_MISC_WAIT|DBG_FUNC_END, error,
                 eqp->ee_req.er_handle,eqp->ee_req.er_eventbits,eqp,0);
    return(error);
  } else {
    if (uap->tv && (timo == 0)) {
        splx(s);
        *retval = 1;  // poll failed
                KERNEL_DEBUG(DBG_MISC_WAIT|DBG_FUNC_END, error,0,0,0,0);
        return(error);
    }

    KERNEL_DEBUG(DBG_MISC_WAIT, 1,&p->p_evlist,0,0,0);
    error = tsleep(&p->p_evlist, PSOCK | PCATCH, "waitevent", timo);
    KERNEL_DEBUG(DBG_MISC_WAIT, 2,&p->p_evlist,0,0,0);
    splx(s);
    if (error == 0)
      goto retry;
    if (error == ERESTART)
      error = EINTR;
    if (error == EWOULDBLOCK) {
      *retval = 1;
      error = 0;
    }
  }
  KERNEL_DEBUG(DBG_MISC_WAIT|DBG_FUNC_END, 0,0,0,0,0);
  return(error);
}

struct modwatch_args {
  struct eventreq *u_req;
  int               u_eventmask;
};

/*
 * 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(p, uap, retval)
     struct proc *p;
     struct modwatch_args *uap;
     register_t *retval;
{
  struct eventreq er;
  struct eventreq *erp = &er;
  struct eventqelt *evq;
  int error;
  struct file *fp;
  struct socket *sp;
  int flag;

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

  // get users request pkt
  if (error = copyin((caddr_t)uap->u_req, (caddr_t)erp,
                     sizeof(struct eventreq))) return(error);

  if (erp->er_type != EV_FD) return(EINVAL);
  if (erp->er_handle < 0) return(EBADF);
  if (erp->er_handle > p->p_fd->fd_nfiles) return(EBADF);
  if ((fp = *fdfile(p, erp->er_handle)) == NULL)
    return(EBADF);
  if (fp->f_type != DTYPE_SOCKET) return(EINVAL); // for now must be sock
  sp = (struct socket *)fp->f_data;
  assert(sp != NULL);


  // locate event if possible
  for (evq = sp->so_evlist.tqh_first;
       evq != NULL; evq = evq->ee_slist.tqe_next) {
    if (evq->ee_proc == p) break;
  }

  if (evq == NULL) {
        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,evq,0,0);

    if (uap->u_eventmask == EV_RM) {
    evprocdeque(p, evq);
    TAILQ_REMOVE(&sp->so_evlist, evq, ee_slist);
    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:
    return(EINVAL);
  }

   evq->ee_eventmask = uap->u_eventmask & EV_MASK;
   evprocdeque(p, evq);
   evq->ee_req.er_eventbits = 0;
   postevent(sp, 0, flag);
   KERNEL_DEBUG(DBG_MISC_MOD|DBG_FUNC_END, evq->ee_req.er_handle,evq->ee_eventmask,sp,flag,0);
   return(0);
}