xref: /illumos-gate/usr/src/uts/common/syscall/pipe.c (revision da6c28aa)

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
/*	  All Rights Reserved  	*/


#pragma ident	"%Z%%M%	%I%	%E% SMI"	/* from SVr4.0 1.11 */

#include <sys/types.h>
#include <sys/sysmacros.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/cred.h>
#include <sys/user.h>
#include <sys/vnode.h>
#include <sys/file.h>
#include <sys/stream.h>
#include <sys/strsubr.h>
#include <sys/errno.h>
#include <sys/debug.h>
#include <sys/fs/fifonode.h>

/*
 * This is the loadable module wrapper.
 */
#include <sys/modctl.h>
#include <sys/syscall.h>

char _depends_on[] = "fs/fifofs";

longlong_t pipe();

static struct sysent pipe_sysent = {
	0,
	SE_32RVAL1 | SE_32RVAL2 | SE_NOUNLOAD | SE_ARGC,
	(int (*)())pipe
};

/*
 * Module linkage information for the kernel.
 */
static struct modlsys modlsys = {
	&mod_syscallops, "pipe(2) syscall", &pipe_sysent
};

#ifdef _SYSCALL32_IMPL
static struct modlsys modlsys32 = {
	&mod_syscallops32, "32-bit pipe(2) syscall", &pipe_sysent
};
#endif

static struct modlinkage modlinkage = {
	MODREV_1,
	&modlsys,
#ifdef _SYSCALL32_IMPL
	&modlsys32,
#endif
	NULL
};

int
_init(void)
{
	return (mod_install(&modlinkage));
}

int
_fini(void)
{
	return (EBUSY);
}

int
_info(struct modinfo *modinfop)
{
	return (mod_info(&modlinkage, modinfop));
}

/*
 * pipe(2) system call.
 * Create a pipe by connecting two streams together. Associate
 * each end of the pipe with a vnode, a file descriptor and
 * one of the streams.
 */
longlong_t
pipe()
{
	vnode_t *vp1, *vp2;
	struct file *fp1, *fp2;
	int error = 0;
	int fd1, fd2;
	rval_t	r;

	/*
	 * Allocate and initialize two vnodes.
	 */
	makepipe(&vp1, &vp2);

	/*
	 * Allocate and initialize two file table entries and two
	 * file pointers. Each file pointer is open for read and
	 * write.
	 */
	if (error = falloc(vp1, FWRITE|FREAD, &fp1, &fd1)) {
		VN_RELE(vp1);
		VN_RELE(vp2);
		return ((longlong_t)set_errno(error));
	}

	if (error = falloc(vp2, FWRITE|FREAD, &fp2, &fd2))
		goto out2;

	/*
	 * Create two stream heads and attach to each vnode.
	 */
	if (error = fifo_stropen(&vp1, FWRITE|FREAD, fp1->f_cred, 0, 0))
		goto out;

	if (error = fifo_stropen(&vp2, FWRITE|FREAD, fp2->f_cred, 0, 0)) {
		(void) VOP_CLOSE(vp1, FWRITE|FREAD, 1, (offset_t)0,
		    fp1->f_cred, NULL);
		goto out;
	}

	strmate(vp1, vp2);

	VTOF(vp1)->fn_ino = VTOF(vp2)->fn_ino = fifogetid();

	/*
	 * Now fill in the entries that falloc reserved
	 */
	mutex_exit(&fp1->f_tlock);
	mutex_exit(&fp2->f_tlock);
	setf(fd1, fp1);
	setf(fd2, fp2);

	/*
	 * Return the file descriptors to the user. They now
	 * point to two different vnodes which have different
	 * stream heads.
	 */
	r.r_val1 = fd1;
	r.r_val2 = fd2;
	return (r.r_vals);
out:
	unfalloc(fp2);
	setf(fd2, NULL);
out2:
	unfalloc(fp1);
	setf(fd1, NULL);
	VN_RELE(vp1);
	VN_RELE(vp2);
	return ((longlong_t)set_errno(error));
}