adtools/clib2

/*
 * $Id: uio_readv.c,v 1.6 2006-01-08 12:04:27 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 _UIO_HEADERS_H
#include "uio_headers.h"
#endif /* _UIO_HEADERS_H */

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

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

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

ssize_t
readv(int file_descriptor,const struct iovec *iov,int vec_count)
{
    ssize_t result = EOF;
    struct file_action_message msg;
    ssize_t total_num_bytes_read;
    ssize_t part_num_bytes_read;
    ssize_t num_bytes_read;
    struct fd * fd = NULL;
    int i;

    ENTER();

    SHOWVALUE(file_descriptor);
    SHOWPOINTER(iov);
    SHOWVALUE(vec_count);

    __stdio_lock();

    #if defined(CHECK_FOR_NULL_POINTERS)
    {
        if(iov == NULL)
        {
            __set_errno(EFAULT);
            goto out;
        }
    }
    #endif /* CHECK_FOR_NULL_POINTERS */

    if(vec_count < 1 || vec_count > MAX_IOVEC)
    {
        __set_errno(EINVAL);
        goto out;
    }

    /* Check for overflow. An expensive test, but better to do it here than in the read loop. */
    for(i = 0, total_num_bytes_read = 0 ; i < vec_count ; i++)
    {
        total_num_bytes_read += iov[i].iov_len;
        if(total_num_bytes_read < 0) /* Rollover. */
        {
            __set_errno(EINVAL);
            goto out;
        }
    }

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

    __fd_lock(fd);

    total_num_bytes_read = 0;
    part_num_bytes_read = 0;

    i = 0;

    while(i < vec_count) /* XXX: Should this loop be locked? */
    {
        if(__check_abort_enabled)
            __check_abort();

        if(iov[i].iov_len > 0)
        {
            msg.fam_Action    = file_action_read;
            msg.fam_Data    = (char *)iov[i].iov_base + part_num_bytes_read;
            msg.fam_Size    = iov[i].iov_len - part_num_bytes_read;

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

            /* End of file reached? */
            if(num_bytes_read == 0)
                break;

            total_num_bytes_read += num_bytes_read;

            part_num_bytes_read += num_bytes_read;
            if((size_t)part_num_bytes_read < iov[i].iov_len)
            {
                /* Avoid busy-waiting for more data here? */
                continue;
            }
        }

        part_num_bytes_read = 0;

        i++;
    }

    result = total_num_bytes_read;

 out:

    __fd_unlock(fd);

    __stdio_unlock();

    RETURN(result);
    return(result);
}