adtools/clib2

/*
 * $Id: fcntl_read.c,v 1.10 2006-01-08 12:04:22 obarthel Exp $
 *
 * :ts=4
 *
 * Portable ISO 'C' (1994) runtime library for the Amiga computer
 * Copyright (c) 2002-2015 by Olaf Barthel <obarthel (at) gmx.net>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Neither the name of Olaf Barthel nor the names of contributors
 *     may be used to endorse or promote products derived from this
 *     software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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.
 */

#ifndef _STDLIB_NULL_POINTER_CHECK_H
#include "stdlib_null_pointer_check.h"
#endif /* _STDLIB_NULL_POINTER_CHECK_H */

/****************************************************************************/

#ifndef _FCNTL_HEADERS_H
#include "fcntl_headers.h"
#endif /* _FCNTL_HEADERS_H */

/****************************************************************************/

/* The following is not part of the ISO 'C' (1994) standard. */

/****************************************************************************/

ssize_t
read(int file_descriptor, void * buffer, size_t num_bytes)
{
    ssize_t num_bytes_read;
    struct fd * fd = NULL;
    ssize_t result = EOF;

    ENTER();

    SHOWVALUE(file_descriptor);
    SHOWPOINTER(buffer);
    SHOWVALUE(num_bytes);

    assert( buffer != NULL );
    assert( (int)num_bytes >= 0);

    if(__check_abort_enabled)
        __check_abort();

    __stdio_lock();

    #if defined(CHECK_FOR_NULL_POINTERS)
    {
        if(buffer == NULL)
        {
            SHOWMSG("invalid buffer");

            __set_errno(EFAULT);
            goto out;
        }
    }
    #endif /* CHECK_FOR_NULL_POINTERS */

    assert( file_descriptor >= 0 && file_descriptor < __num_fd );
    assert( __fd[file_descriptor] != NULL );
    assert( FLAG_IS_SET(__fd[file_descriptor]->fd_Flags,FDF_IN_USE) );

    fd = __get_file_descriptor(file_descriptor);
    if(fd == NULL)
    {
        __set_errno(EBADF);
        goto out;
    }

    __fd_lock(fd);

    if(FLAG_IS_CLEAR(fd->fd_Flags,FDF_READ))
    {
        SHOWMSG("this descriptor is not read-enabled");

        __set_errno(EBADF);
        goto out;
    }

    if(num_bytes > 0)
    {
        struct file_action_message fam;

        SHOWMSG("calling the hook");

        fam.fam_Action    = file_action_read;
        fam.fam_Data    = buffer;
        fam.fam_Size    = num_bytes;

        assert( fd->fd_Action != NULL );

        num_bytes_read = (*fd->fd_Action)(fd,&fam);
        if(num_bytes_read == EOF)
        {
            __set_errno(fam.fam_Error);
            goto out;
        }
    }
    else
    {
        num_bytes_read = 0;
    }

    result = num_bytes_read;

 out:

    __fd_unlock(fd);

    __stdio_unlock();

    RETURN(result);
    return(result);
}