freebsd-src/sys/fs/fifofs/fifo_vnops.c

/*
 * Copyright (c) 1990, 1993
 *	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	8.2 (Berkeley) 1/4/94
 */

#include <sys/param.h>
#include <sys/proc.h>
#include <sys/time.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/stat.h>
#include <sys/systm.h>
#include <sys/ioctl.h>
#include <sys/file.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <miscfs/fifofs/fifo.h>

/*
 * This structure is associated with the FIFO vnode and stores
 * the state associated with the FIFO.
 */
struct fifoinfo {
	struct socket	*fi_readsock;
	struct socket	*fi_writesock;
	long		fi_readers;
	long		fi_writers;
};

int (**fifo_vnodeop_p)();
struct vnodeopv_entry_desc fifo_vnodeop_entries[] = {
	{ &vop_default_desc, vn_default_error },
	{ &vop_lookup_desc, fifo_lookup },		/* lookup */
	{ &vop_create_desc, fifo_create },		/* create */
	{ &vop_mknod_desc, fifo_mknod },		/* mknod */
	{ &vop_open_desc, fifo_open },			/* open */
	{ &vop_close_desc, fifo_close },		/* close */
	{ &vop_access_desc, fifo_access },		/* access */
	{ &vop_getattr_desc, fifo_getattr },		/* getattr */
	{ &vop_setattr_desc, fifo_setattr },		/* setattr */
	{ &vop_read_desc, fifo_read },			/* read */
	{ &vop_write_desc, fifo_write },		/* write */
	{ &vop_ioctl_desc, fifo_ioctl },		/* ioctl */
	{ &vop_select_desc, fifo_select },		/* select */
	{ &vop_mmap_desc, fifo_mmap },			/* mmap */
	{ &vop_fsync_desc, fifo_fsync },		/* fsync */
	{ &vop_seek_desc, fifo_seek },			/* seek */
	{ &vop_remove_desc, fifo_remove },		/* remove */
	{ &vop_link_desc, fifo_link },			/* link */
	{ &vop_rename_desc, fifo_rename },		/* rename */
	{ &vop_mkdir_desc, fifo_mkdir },		/* mkdir */
	{ &vop_rmdir_desc, fifo_rmdir },		/* rmdir */
	{ &vop_symlink_desc, fifo_symlink },		/* symlink */
	{ &vop_readdir_desc, fifo_readdir },		/* readdir */
	{ &vop_readlink_desc, fifo_readlink },		/* readlink */
	{ &vop_abortop_desc, fifo_abortop },		/* abortop */
	{ &vop_inactive_desc, fifo_inactive },		/* inactive */
	{ &vop_reclaim_desc, fifo_reclaim },		/* reclaim */
	{ &vop_lock_desc, fifo_lock },			/* lock */
	{ &vop_unlock_desc, fifo_unlock },		/* unlock */
	{ &vop_bmap_desc, fifo_bmap },			/* bmap */
	{ &vop_strategy_desc, fifo_strategy },		/* strategy */
	{ &vop_print_desc, fifo_print },		/* print */
	{ &vop_islocked_desc, fifo_islocked },		/* islocked */
	{ &vop_pathconf_desc, fifo_pathconf },		/* pathconf */
	{ &vop_advlock_desc, fifo_advlock },		/* advlock */
	{ &vop_blkatoff_desc, fifo_blkatoff },		/* blkatoff */
	{ &vop_valloc_desc, fifo_valloc },		/* valloc */
	{ &vop_vfree_desc, fifo_vfree },		/* vfree */
	{ &vop_truncate_desc, fifo_truncate },		/* truncate */
	{ &vop_update_desc, fifo_update },		/* update */
	{ &vop_bwrite_desc, fifo_bwrite },		/* bwrite */
	{ (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(ap)
	struct vop_lookup_args /* {
		struct vnode * a_dvp;
		struct vnode ** a_vpp;
		struct componentname * a_cnp;
	} */ *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(ap)
	struct vop_open_args /* {
		struct vnode *a_vp;
		int  a_mode;
		struct ucred *a_cred;
		struct proc *a_p;
	} */ *ap;
{
	register struct vnode *vp = ap->a_vp;
	register struct fifoinfo *fip;
	struct socket *rso, *wso;
	int error;
	static char openstr[] = "fifo";

	if ((ap->a_mode & (FREAD|FWRITE)) == (FREAD|FWRITE))
		return (EINVAL);
	if ((fip = vp->v_fifoinfo) == NULL) {
		MALLOC(fip, struct fifoinfo *, sizeof(*fip), M_VNODE, M_WAITOK);
		vp->v_fifoinfo = fip;
		if (error = socreate(AF_UNIX, &rso, SOCK_STREAM, 0)) {
			free(fip, M_VNODE);
			vp->v_fifoinfo = NULL;
			return (error);
		}
		fip->fi_readsock = rso;
		if (error = socreate(AF_UNIX, &wso, SOCK_STREAM, 0)) {
			(void)soclose(rso);
			free(fip, M_VNODE);
			vp->v_fifoinfo = NULL;
			return (error);
		}
		fip->fi_writesock = wso;
		if (error = unp_connect2(wso, rso)) {
			(void)soclose(wso);
			(void)soclose(rso);
			free(fip, M_VNODE);
			vp->v_fifoinfo = NULL;
			return (error);
		}
		fip->fi_readers = fip->fi_writers = 0;
		wso->so_state |= SS_CANTRCVMORE;
		rso->so_state |= SS_CANTSENDMORE;
	}
	error = 0;
	if (ap->a_mode & FREAD) {
		fip->fi_readers++;
		if (fip->fi_readers == 1) {
			fip->fi_writesock->so_state &= ~SS_CANTSENDMORE;
			if (fip->fi_writers > 0)
				wakeup((caddr_t)&fip->fi_writers);
		}
		if (ap->a_mode & O_NONBLOCK)
			return (0);
		while (fip->fi_writers == 0) {
			VOP_UNLOCK(vp);
			error = tsleep((caddr_t)&fip->fi_readers,
			    PCATCH | PSOCK, openstr, 0);
			VOP_LOCK(vp);
			if (error)
				break;
		}
	} else {
		fip->fi_writers++;
		if (fip->fi_readers == 0 && (ap->a_mode & O_NONBLOCK)) {
			error = ENXIO;
		} else {
			if (fip->fi_writers == 1) {
				fip->fi_readsock->so_state &= ~SS_CANTRCVMORE;
				if (fip->fi_readers > 0)
					wakeup((caddr_t)&fip->fi_readers);
			}
			while (fip->fi_readers == 0) {
				VOP_UNLOCK(vp);
				error = tsleep((caddr_t)&fip->fi_writers,
				    PCATCH | PSOCK, openstr, 0);
				VOP_LOCK(vp);
				if (error)
					break;
			}
		}
	}
	if (error)
		VOP_CLOSE(vp, ap->a_mode, ap->a_cred, ap->a_p);
	return (error);
}

/*
 * Vnode op for read
 */
/* ARGSUSED */
int
fifo_read(ap)
	struct vop_read_args /* {
		struct vnode *a_vp;
		struct uio *a_uio;
		int  a_ioflag;
		struct ucred *a_cred;
	} */ *ap;
{
	register struct uio *uio = ap->a_uio;
	register struct socket *rso = ap->a_vp->v_fifoinfo->fi_readsock;
	int error, startresid;

#ifdef DIAGNOSTIC
	if (uio->uio_rw != UIO_READ)
		panic("fifo_read mode");
#endif
	if (uio->uio_resid == 0)
		return (0);
	if (ap->a_ioflag & IO_NDELAY)
		rso->so_state |= SS_NBIO;
	startresid = uio->uio_resid;
	VOP_UNLOCK(ap->a_vp);
	error = soreceive(rso, (struct mbuf **)0, uio, (int *)0,
		(struct mbuf **)0, (struct mbuf **)0);
	VOP_LOCK(ap->a_vp);
	/*
	 * Clear EOF indication after first such return.
	 */
	if (uio->uio_resid == startresid)
		rso->so_state &= ~SS_CANTRCVMORE;
	if (ap->a_ioflag & IO_NDELAY)
		rso->so_state &= ~SS_NBIO;
	return (error);
}

/*
 * Vnode op for write
 */
/* ARGSUSED */
int
fifo_write(ap)
	struct vop_write_args /* {
		struct vnode *a_vp;
		struct uio *a_uio;
		int  a_ioflag;
		struct ucred *a_cred;
	} */ *ap;
{
	struct socket *wso = ap->a_vp->v_fifoinfo->fi_writesock;
	int error;

#ifdef DIAGNOSTIC
	if (ap->a_uio->uio_rw != UIO_WRITE)
		panic("fifo_write mode");
#endif
	if (ap->a_ioflag & IO_NDELAY)
		wso->so_state |= SS_NBIO;
	VOP_UNLOCK(ap->a_vp);
	error = sosend(wso, (struct mbuf *)0, ap->a_uio, 0, (struct mbuf *)0, 0);
	VOP_LOCK(ap->a_vp);
	if (ap->a_ioflag & IO_NDELAY)
		wso->so_state &= ~SS_NBIO;
	return (error);
}

/*
 * Device ioctl operation.
 */
/* ARGSUSED */
int
fifo_ioctl(ap)
	struct vop_ioctl_args /* {
		struct vnode *a_vp;
		int  a_command;
		caddr_t  a_data;
		int  a_fflag;
		struct ucred *a_cred;
		struct proc *a_p;
	} */ *ap;
{
	struct file filetmp;

	if (ap->a_command == FIONBIO)
		return (0);
	if (ap->a_fflag & FREAD)
		filetmp.f_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_readsock;
	else
		filetmp.f_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_writesock;
	return (soo_ioctl(&filetmp, ap->a_command, ap->a_data, ap->a_p));
}

/* ARGSUSED */
int
fifo_select(ap)
	struct vop_select_args /* {
		struct vnode *a_vp;
		int  a_which;
		int  a_fflags;
		struct ucred *a_cred;
		struct proc *a_p;
	} */ *ap;
{
	struct file filetmp;

	if (ap->a_fflags & FREAD)
		filetmp.f_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_readsock;
	else
		filetmp.f_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_writesock;
	return (soo_select(&filetmp, ap->a_which, ap->a_p));
}

/*
 * This is a noop, simply returning what one has been given.
 */
int
fifo_bmap(ap)
	struct vop_bmap_args /* {
		struct vnode *a_vp;
		daddr_t  a_bn;
		struct vnode **a_vpp;
		daddr_t *a_bnp;
	} */ *ap;
{

	if (ap->a_vpp != NULL)
		*ap->a_vpp = ap->a_vp;
	if (ap->a_bnp != NULL)
		*ap->a_bnp = ap->a_bn;
	return (0);
}

/*
 * At the moment we do not do any locking.
 */
/* ARGSUSED */
int
fifo_lock(ap)
	struct vop_lock_args /* {
		struct vnode *a_vp;
	} */ *ap;
{

	return (0);
}

/* ARGSUSED */
int
fifo_unlock(ap)
	struct vop_unlock_args /* {
		struct vnode *a_vp;
	} */ *ap;
{

	return (0);
}

/*
 * Device close routine
 */
/* ARGSUSED */
int
fifo_close(ap)
	struct vop_close_args /* {
		struct vnode *a_vp;
		int  a_fflag;
		struct ucred *a_cred;
		struct proc *a_p;
	} */ *ap;
{
	register struct vnode *vp = ap->a_vp;
	register struct fifoinfo *fip = vp->v_fifoinfo;
	int error1, error2;

	if (ap->a_fflag & FWRITE) {
		fip->fi_writers--;
		if (fip->fi_writers == 0)
			socantrcvmore(fip->fi_readsock);
	} else {
		fip->fi_readers--;
		if (fip->fi_readers == 0)
			socantsendmore(fip->fi_writesock);
	}
	if (vp->v_usecount > 1)
		return (0);
	error1 = soclose(fip->fi_readsock);
	error2 = soclose(fip->fi_writesock);
	FREE(fip, M_VNODE);
	vp->v_fifoinfo = NULL;
	if (error1)
		return (error1);
	return (error2);
}

/*
 * Print out the contents of a fifo vnode.
 */
int
fifo_print(ap)
	struct vop_print_args /* {
		struct vnode *a_vp;
	} */ *ap;
{

	printf("tag VT_NON");
	fifo_printinfo(ap->a_vp);
	printf("\n");
	return (0);
}

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

	printf(", fifo with %d readers and %d writers",
		fip->fi_readers, fip->fi_writers);
	return (0);
}

/*
 * Return POSIX pathconf information applicable to fifo's.
 */
int
fifo_pathconf(ap)
	struct vop_pathconf_args /* {
		struct vnode *a_vp;
		int a_name;
		int *a_retval;
	} */ *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 = 1;
		return (0);
	default:
		return (EINVAL);
	}
	/* NOTREACHED */
}

/*
 * Fifo failed operation
 */
int
fifo_ebadf()
{

	return (EBADF);
}

/*
 * Fifo advisory byte-level locks.
 */
/* ARGSUSED */
int
fifo_advlock(ap)
	struct vop_advlock_args /* {
		struct vnode *a_vp;
		caddr_t  a_id;
		int  a_op;
		struct flock *a_fl;
		int  a_flags;
	} */ *ap;
{

	return (EOPNOTSUPP);
}

/*
 * Fifo bad operation
 */
int
fifo_badop()
{

	panic("fifo_badop called");
	/* NOTREACHED */
}