common/syscall/pipe.c

/*
 * 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)) != 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 flag
     */
    if ((flags & FCLOEXEC) != 0) {
        f_setfd(fd1, FD_CLOEXEC);
        f_setfd(fd2, FD_CLOEXEC);
    }

    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));
}