[apple/xnu.git] / bsd / miscfs / fifofs / fifo_vnops.c

/*
 * Copyright (c) 2000-2006 Apple Computer, 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) 1990, 1993, 1995
 *      The Regents of the University of California.  All rights reserved.
 *
 * 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.
 *
 *      @(#)fifo_vnops.c        8.4 (Berkeley) 8/10/94
 */

#include <sys/param.h>
#include <sys/proc.h>
#include <sys/time.h>
#include <sys/namei.h>
#include <sys/vnode_internal.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/stat.h>
#include <sys/systm.h>
#include <sys/ioctl.h>
#include <sys/file_internal.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <miscfs/fifofs/fifo.h>
#include <vfs/vfs_support.h>

#define VOPFUNC int (*)(void *)

extern int      soo_ioctl(struct fileproc *fp, u_long cmd, caddr_t data, vfs_context_t ctx);
extern int      soo_select(struct fileproc *fp, int which, void * wql, vfs_context_t ctx);

int (**fifo_vnodeop_p)(void *);
struct vnodeopv_entry_desc fifo_vnodeop_entries[] = {
        { &vnop_default_desc, (VOPFUNC)vn_default_error },
        { &vnop_lookup_desc, (VOPFUNC)fifo_lookup },            /* lookup */
        { &vnop_create_desc, (VOPFUNC)err_create },             /* create */
        { &vnop_mknod_desc, (VOPFUNC)err_mknod },               /* mknod */
        { &vnop_open_desc, (VOPFUNC)fifo_open },                        /* open */
        { &vnop_close_desc, (VOPFUNC)fifo_close },              /* close */
        { &vnop_access_desc, (VOPFUNC)fifo_access },            /* access */
        { &vnop_getattr_desc, (VOPFUNC)fifo_getattr },          /* getattr */
        { &vnop_setattr_desc, (VOPFUNC)fifo_setattr },          /* setattr */
        { &vnop_read_desc, (VOPFUNC)fifo_read },                        /* read */
        { &vnop_write_desc, (VOPFUNC)fifo_write },              /* write */
        { &vnop_ioctl_desc, (VOPFUNC)fifo_ioctl },              /* ioctl */
        { &vnop_select_desc, (VOPFUNC)fifo_select },            /* select */
        { &vnop_revoke_desc, (VOPFUNC)fifo_revoke },            /* revoke */
        { &vnop_mmap_desc, (VOPFUNC)err_mmap },                 /* mmap */
        { &vnop_fsync_desc, (VOPFUNC)fifo_fsync },              /* fsync */
        { &vnop_remove_desc, (VOPFUNC)err_remove },             /* remove */
        { &vnop_link_desc, (VOPFUNC)err_link },                 /* link */
        { &vnop_rename_desc, (VOPFUNC)err_rename },             /* rename */
        { &vnop_mkdir_desc, (VOPFUNC)err_mkdir },               /* mkdir */
        { &vnop_rmdir_desc, (VOPFUNC)err_rmdir },               /* rmdir */
        { &vnop_symlink_desc, (VOPFUNC)err_symlink },           /* symlink */
        { &vnop_readdir_desc, (VOPFUNC)err_readdir },           /* readdir */
        { &vnop_readlink_desc, (VOPFUNC)err_readlink },         /* readlink */
        { &vnop_inactive_desc, (VOPFUNC)fifo_inactive },                /* inactive */
        { &vnop_reclaim_desc, (VOPFUNC)fifo_reclaim },          /* reclaim */
        { &vnop_strategy_desc, (VOPFUNC)err_strategy },         /* strategy */
        { &vnop_pathconf_desc, (VOPFUNC)fifo_pathconf },                /* pathconf */
        { &vnop_advlock_desc, (VOPFUNC)fifo_advlock },          /* advlock */
        { &vnop_bwrite_desc, (VOPFUNC)fifo_bwrite },            /* bwrite */
        { &vnop_pagein_desc, (VOPFUNC)err_pagein },             /* Pagein */
        { &vnop_pageout_desc, (VOPFUNC)err_pageout },           /* Pageout */
        { &vnop_copyfile_desc, (VOPFUNC)err_copyfile },         /* Copyfile */
        { &vnop_blktooff_desc, (VOPFUNC)err_blktooff },         /* blktooff */
        { &vnop_offtoblk_desc, (VOPFUNC)err_offtoblk },         /* offtoblk */
        { &vnop_blockmap_desc, (VOPFUNC)err_blockmap },                 /* blockmap */
        { (struct vnodeop_desc*)NULL, (int(*)())NULL }
};
struct vnodeopv_desc fifo_vnodeop_opv_desc =
        { &fifo_vnodeop_p, fifo_vnodeop_entries };

/*
 * Trivial lookup routine that always fails.
 */
/* ARGSUSED */
int
fifo_lookup(struct vnop_lookup_args *ap)
{
        
        *ap->a_vpp = NULL;
        return (ENOTDIR);
}

/*
 * Open called to set up a new instance of a fifo or
 * to find an active instance of a fifo.
 */
/* ARGSUSED */
int
fifo_open(struct vnop_open_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct fifoinfo *fip;
        struct socket *rso, *wso;
        int error;

        vnode_lock(vp);

retry:

        fip = vp->v_fifoinfo;

        if (fip == (struct fifoinfo *)0)
                panic("fifo_open with no fifoinfo");

        if ((fip->fi_flags & FIFO_CREATED) == 0) {
                if (fip->fi_flags & FIFO_INCREATE) {
                        fip->fi_flags |= FIFO_CREATEWAIT;       
                        error = msleep(&fip->fi_flags, &vp->v_lock, PRIBIO | PCATCH, "fifocreatewait", NULL);
                        if (error) {
                                vnode_unlock(vp);
                                return(error);
                        }
                        goto retry;
                } else {
                        fip->fi_flags |= FIFO_INCREATE; 
                        vnode_unlock(vp);
                        if ( (error = socreate(AF_LOCAL, &rso, SOCK_STREAM, 0)) ) {
                                goto bad1;
                        }

                        if ( (error = socreate(AF_LOCAL, &wso, SOCK_STREAM, 0)) ) {
                                (void)soclose(rso);
                                goto bad1;
                        }

                        if ( (error = soconnect2(wso, rso)) ) {
                                (void)soclose(wso);
                                (void)soclose(rso);
                                goto bad1;
                        }
                        fip->fi_readers = fip->fi_writers = 0;

                        /* Lock ordering between wso and rso does not matter here 
                         * because they are just created and no one has a reference to them
                         */
                        socket_lock(wso, 1);
                        wso->so_state |= SS_CANTRCVMORE;
                        wso->so_snd.sb_lowat = PIPE_BUF;
                        socket_unlock(wso, 1);

                        socket_lock(rso, 1);
                        rso->so_state |= SS_CANTSENDMORE;
                        socket_unlock(rso, 1);

                        vnode_lock(vp);
                        fip->fi_readsock = rso;
                        fip->fi_writesock = wso;

                        fip->fi_flags |= FIFO_CREATED;
                        fip->fi_flags &= ~FIFO_INCREATE;
                        
                        if ((fip->fi_flags & FIFO_CREATEWAIT)) {
                                fip->fi_flags &= ~FIFO_CREATEWAIT;
                                wakeup(&fip->fi_flags);
                        }
                        /* vnode lock is held  to process further */
                }
        }

        /* vnode is locked at this point */
        /* fifo in created already */
        if (ap->a_mode & FREAD) {
                fip->fi_readers++;
                if (fip->fi_readers == 1) {
                        socket_lock(fip->fi_writesock, 1);
                        fip->fi_writesock->so_state &= ~SS_CANTSENDMORE;
                        socket_unlock(fip->fi_writesock, 1);

                        if (fip->fi_writers > 0)
                                wakeup((caddr_t)&fip->fi_writers);
                }
        }
        if (ap->a_mode & FWRITE) {
                fip->fi_writers++;
                if (fip->fi_writers == 1) {
                        socket_lock(fip->fi_readsock, 1);
                        fip->fi_readsock->so_state &= ~SS_CANTRCVMORE;
                        socket_unlock(fip->fi_readsock, 1);
        
                        if (fip->fi_readers > 0)
                                wakeup((caddr_t)&fip->fi_readers);
                }
        }
        if ((ap->a_mode & FREAD) && (ap->a_mode & O_NONBLOCK) == 0) {
                if (fip->fi_writers == 0) {
                        error = msleep((caddr_t)&fip->fi_readers, &vp->v_lock,
                                        PCATCH | PSOCK, "fifoor", NULL);
                        if (error)
                                goto bad;
                        if (fip->fi_readers == 1) {
                                if (fip->fi_writers > 0)
                                        wakeup((caddr_t)&fip->fi_writers);
                        }
                }
        }
        if (ap->a_mode & FWRITE) {
                if (ap->a_mode & O_NONBLOCK) {
                        if (fip->fi_readers == 0) {
                                        error = ENXIO;
                                        goto bad;
                        }
                } else {
                        if (fip->fi_readers == 0) {
                                error = msleep((caddr_t)&fip->fi_writers,&vp->v_lock,
                                                PCATCH | PSOCK, "fifoow", NULL);
                                if (error)
                                        goto bad;
                                if (fip->fi_writers == 1) {
                                        if (fip->fi_readers > 0)
                                                wakeup((caddr_t)&fip->fi_readers);
                                }
                        }
                }
        }

        vnode_unlock(vp);
        return (0);
bad:
        fifo_close_internal(vp, ap->a_mode, ap->a_context, 1);

        vnode_unlock(vp);
        return (error);
bad1:
        vnode_lock(vp);

        fip->fi_flags &= ~FIFO_INCREATE;
                        
        if ((fip->fi_flags & FIFO_CREATEWAIT)) {
                fip->fi_flags &= ~FIFO_CREATEWAIT;
                wakeup(&fip->fi_flags);
        }
        vnode_unlock(vp);

        return (error);
}

/*
 * Vnode op for read
 */
int
fifo_read(struct vnop_read_args *ap)
{
        struct uio *uio = ap->a_uio;
        struct socket *rso = ap->a_vp->v_fifoinfo->fi_readsock;
        user_ssize_t startresid;
        int error;
        int rflags;

#if DIAGNOSTIC
        if (uio->uio_rw != UIO_READ)
                panic("fifo_read mode");
#endif
        if (uio_resid(uio) == 0)
                return (0);

        rflags = (ap->a_ioflag & IO_NDELAY) ? MSG_NBIO : 0;

        startresid = uio_resid(uio);

        /* fifo conformance - if we have a reader open on the fifo but no 
         * writers then we need to make sure we do not block.  We do that by 
         * checking the receive buffer and if empty set error to EWOULDBLOCK.
         * If error is set to EWOULDBLOCK we skip the call into soreceive
         */
        error = 0;
        if (ap->a_vp->v_fifoinfo->fi_writers < 1) {
                socket_lock(rso, 1);
                error = (rso->so_rcv.sb_cc == 0) ? EWOULDBLOCK : 0;
                socket_unlock(rso, 1);
        }

        /* skip soreceive to avoid blocking when we have no writers */
        if (error != EWOULDBLOCK) {
                error = soreceive(rso, (struct sockaddr **)0, uio, (struct mbuf **)0,
                                                (struct mbuf **)0, &rflags);
        }
        else {
                /* clear EWOULDBLOCK and return EOF (zero) */
                error = 0;
        }
        /*
         * Clear EOF indication after first such return.
         */
        if (uio_resid(uio) == startresid) {
                socket_lock(rso, 1);
                rso->so_state &= ~SS_CANTRCVMORE;
                socket_unlock(rso, 1);
        }
        return (error);
}

/*
 * Vnode op for write
 */
int
fifo_write(struct vnop_write_args *ap)
{
        struct socket *wso = ap->a_vp->v_fifoinfo->fi_writesock;
        int error;

#if DIAGNOSTIC
        if (ap->a_uio->uio_rw != UIO_WRITE)
                panic("fifo_write mode");
#endif
        error = sosend(wso, (struct sockaddr *)0, ap->a_uio, NULL,
                       (struct mbuf *)0, (ap->a_ioflag & IO_NDELAY) ? MSG_NBIO : 0);

        return (error);
}

/*
 * Device ioctl operation.
 */
int
fifo_ioctl(struct vnop_ioctl_args *ap)
{
        struct fileproc filetmp;
        struct fileglob filefg;
        int error;

        if (ap->a_command == FIONBIO)
                return (0);
        bzero(&filetmp, sizeof(struct fileproc));
        filetmp.f_fglob = &filefg;
        if (ap->a_fflag & FREAD) {
                filetmp.f_fglob->fg_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_readsock;
                error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, ap->a_context);
                if (error)
                        return (error);
        }
        if (ap->a_fflag & FWRITE) {
                filetmp.f_fglob->fg_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_writesock;
                error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, ap->a_context);
                if (error)
                        return (error);
        }
        return (0);
}

int
fifo_select(struct vnop_select_args *ap)
{
        struct fileproc filetmp;
        struct fileglob filefg;
        int ready;

        bzero(&filetmp, sizeof(struct fileproc));
        filetmp.f_fglob = &filefg;
        if (ap->a_which & FREAD) {
                filetmp.f_fglob->fg_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_readsock;
                ready = soo_select(&filetmp, ap->a_which, ap->a_wql, ap->a_context);
                if (ready)
                        return (ready);
        }
        if (ap->a_which & FWRITE) {
                filetmp.f_fglob->fg_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_writesock;
                ready = soo_select(&filetmp, ap->a_which, ap->a_wql, ap->a_context);
                if (ready)
                        return (ready);
        }
        return (0);
}

int
fifo_inactive(__unused struct vnop_inactive_args *ap)
{
        return (0);
}


/*
 * Device close routine
 */
int
fifo_close(struct vnop_close_args *ap)
{
        return fifo_close_internal(ap->a_vp, ap->a_fflag, ap->a_context, 0);
}

int
fifo_close_internal(vnode_t vp, int fflag, __unused vfs_context_t context, int locked)
{
        struct fifoinfo *fip = vp->v_fifoinfo;
        int error1, error2;
        struct socket *rso;
        struct socket *wso;

        if (!locked)
                vnode_lock(vp);

        if ((fip->fi_flags & FIFO_CREATED) == 0) {
                if (!locked)
                        vnode_unlock(vp);
                return(0);

        }
                
        if (fflag & FREAD) {
                fip->fi_readers--;
                if (fip->fi_readers == 0){
                        socket_lock(fip->fi_writesock, 1);
                        socantsendmore(fip->fi_writesock);
                        socket_unlock(fip->fi_writesock, 1);
                }
        }

        if (fflag & FWRITE) {
                fip->fi_writers--;
                if (fip->fi_writers == 0) {
                        socket_lock(fip->fi_readsock, 1);
                        socantrcvmore(fip->fi_readsock);
                        socket_unlock(fip->fi_readsock, 1);
                }
        }
#if 0
        if (vnode_isinuse_locked(vp, 0, 1)) {
                if (!locked)
                        vnode_unlock(vp);
                return (0);
        }
#endif

        if (fip->fi_writers || fip->fi_readers) {
                if (!locked)
                        vnode_unlock(vp);
                return (0);
        }

        wso = fip->fi_writesock;
        rso = fip->fi_readsock;
        fip->fi_readsock = NULL;
        fip->fi_writesock = NULL;
        fip->fi_flags &= ~FIFO_CREATED;
        if (!locked)
                vnode_unlock(vp);
        error1 = soclose(rso);
        error2 = soclose(wso);

        if (error1)
                return (error1);
        return (error2);
}

/*
 * Print out internal contents of a fifo vnode.
 */
void
fifo_printinfo(struct vnode *vp)
{
        struct fifoinfo *fip = vp->v_fifoinfo;

        printf(", fifo with %ld readers and %ld writers",
                fip->fi_readers, fip->fi_writers);
}

/*
 * Return POSIX pathconf information applicable to fifo's.
 */
int
fifo_pathconf(struct vnop_pathconf_args *ap)
{
        switch (ap->a_name) {
        case _PC_LINK_MAX:
                *ap->a_retval = LINK_MAX;
                return (0);
        case _PC_PIPE_BUF:
                *ap->a_retval = PIPE_BUF;
                return (0);
        case _PC_CHOWN_RESTRICTED:
                *ap->a_retval = 200112;         /* _POSIX_CHOWN_RESTRICTED */
                return (0);
        default:
                return (EINVAL);
        }
        /* NOTREACHED */
}

/*
 * Fifo failed operation
 */
int
fifo_ebadf(__unused void *dummy)
{

        return (EBADF);
}

/*
 * Fifo advisory byte-level locks.
 */
int
fifo_advlock(__unused struct vnop_advlock_args *ap)
{

        return (ENOTSUP);
}


/* You'd certainly better have an iocount on the vnode! */
int
fifo_freespace(struct vnode *vp, long *count) 
{
        struct socket *rsock;
        rsock = vp->v_fifoinfo->fi_readsock;
        socket_lock(rsock, 1);
        *count = sbspace(&rsock->so_rcv);
        socket_unlock(rsock, 1);
        return 0;
}

int
fifo_charcount(struct vnode *vp, int *count) 
{
        int mcount;
        int err = sock_ioctl(vp->v_fifoinfo->fi_readsock, FIONREAD, (void*)&mcount);
        if (err == 0) {
                *count = mcount;
        }
        return err;
}