/*
 * 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 2013 OmniTI Computer Consulting, Inc. All rights reserved.
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 * Copyright (c) 2011 Bayard G. Bell. All rights reserved.
 */

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


#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>
#include <sys/fcntl.h>

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

int pipe(intptr_t fds, int);

static struct sysent pipe_sysent = {
        2,
        SE_ARGC | SE_32RVAL1 | SE_NOUNLOAD,
        (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.
 */
int
pipe(intptr_t arg, int flags)
{
        vnode_t *vp1, *vp2;
        struct file *fp1, *fp2;
        int error = 0;
        int flag1, flag2, iflags;
        int fd1, fd2;

        /*
         * Validate allowed flags.
         */
        if ((flags & ~(FCLOEXEC|FNONBLOCK|FCLOFORK)) != 0) {
                return (set_errno(EINVAL));
        }
        /*
         * 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 (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();

        /*
         * Set the O_NONBLOCK flag if requested.
         */
        if (flags & FNONBLOCK) {
                flag1 = fp1->f_flag;
                flag2 = fp2->f_flag;
                iflags = flags & FNONBLOCK;

                if (error = VOP_SETFL(vp1, flag1, iflags, fp1->f_cred, NULL)) {
                        goto out_vop_close;
                }
                fp1->f_flag |= iflags;

                if (error = VOP_SETFL(vp2, flag2, iflags, fp2->f_cred, NULL)) {
                        goto out_vop_close;
                }
                fp2->f_flag |= iflags;
        }

        /*
         * Return the file descriptors to the user. They now
         * point to two different vnodes which have different
         * stream heads.
         */
        if (copyout(&fd1, &((int *)arg)[0], sizeof (int)) ||
            copyout(&fd2, &((int *)arg)[1], sizeof (int))) {
                error = EFAULT;
                goto out_vop_close;
        }

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

        /*
         * Optionally set the FCLOEXEC and FCLOFORK flags
         */
        if ((flags & FCLOEXEC) != 0) {
                f_setfd_or(fd1, FD_CLOEXEC);
                f_setfd_or(fd2, FD_CLOEXEC);
        }

        if ((flags & FCLOFORK) != 0) {
                f_setfd_or(fd1, FD_CLOFORK);
                f_setfd_or(fd2, FD_CLOFORK);
        }

        return (0);
out_vop_close:
        (void) VOP_CLOSE(vp1, FWRITE|FREAD, 1, (offset_t)0, fp1->f_cred, NULL);
        (void) VOP_CLOSE(vp2, FWRITE|FREAD, 1, (offset_t)0, fp2->f_cred, NULL);
out:
        setf(fd2, NULL);
        unfalloc(fp2);
out2:
        setf(fd1, NULL);
        unfalloc(fp1);
        VN_RELE(vp1);
        VN_RELE(vp2);
        return (set_errno(error));
}