libexplain/iocontrol/vidiocgchan.c

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/*
 * libexplain - a library of system-call-specific strerror replacements
 * Copyright (C) 2011, 2013 Peter Miller
 * Written by Peter Miller <pmiller@opensource.org.au>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include <libexplain/ac/errno.h>
#include <libexplain/ac/linux/videodev.h>
#include <libexplain/ac/sys/ioctl.h>

#include <libexplain/buffer/einval.h>
#include <libexplain/buffer/is_the_null_pointer.h>
#include <libexplain/buffer/video_channel.h>
#include <libexplain/iocontrol/generic.h>
#include <libexplain/iocontrol/vidiocgchan.h>
#include <libexplain/is_efault.h>

#ifdef VIDIOCGCHAN


static void
print_data(const explain_iocontrol_t *p, explain_string_buffer_t *sb,
    int errnum, int fildes, int request, const void *data)
{
    (void)p;
    (void)errnum;
    (void)fildes;
    (void)request;
    explain_buffer_video_channel(sb, data, 0);
}


static void
print_explanation(const explain_iocontrol_t *p, explain_string_buffer_t *sb,
    int errnum, int fildes, int request, const void *data)
{
    switch (errnum)
    {
    case EINVAL:
        if (!data)
        {
            explain_buffer_is_the_null_pointer(sb, "data");
            return;
        }

        {
            const struct video_channel *arg;

            arg = data;
            if (!explain_is_efault_pointer(arg, sizeof(*arg)))
            {
                int             nchannels;

                nchannels = explain_video_channel_get_n(fildes);

                /* pre-3.1: the ioctl may not be supported */
                if (nchannels == 0)
                {
                    explain_iocontrol_generic_print_explanation
                    (
                        p,
                        sb,
                        ENOTTY,
                        fildes,
                        request,
                        data
                    );
                    return;
                }

                /* the channel number may be out of range */
                if
                (
                    nchannels > 0
                &&
                    (unsigned)arg->channel >= (unsigned)nchannels
                )
                {
                    explain_buffer_einval_out_of_range
                    (
                        sb,
                        "data->channel",
                        0,
                        nchannels - 1
                    );
                    return;
                }
            }
        }

        /* no idea */
        explain_buffer_einval_vague(sb, "data");
        break;

    default:
        explain_iocontrol_generic_print_explanation
        (
            p,
            sb,
            errnum,
            fildes,
            request,
            data
        );
        break;
    }
}


static void
print_data_returned(const explain_iocontrol_t *p, explain_string_buffer_t *sb,
    int errnum, int fildes, int request, const void *data)
{
    (void)p;
    (void)errnum;
    (void)fildes;
    (void)request;
    explain_buffer_video_channel(sb, data, 1);
}


const explain_iocontrol_t explain_iocontrol_vidiocgchan =
{
    "VIDIOCGCHAN", /* name */
    VIDIOCGCHAN, /* value */
    0, /* disambiguate */
    0, /* print_name */
    print_data,
    print_explanation,
    print_data_returned,
    sizeof(struct video_channel), /* data_size */
    "struct video_channel *", /* data_type */
    0, /* flags */
    __FILE__,
    __LINE__,
};

#else /* ndef VIDIOCGCHAN */

const explain_iocontrol_t explain_iocontrol_vidiocgchan =
{
    0, /* name */
    0, /* value */
    0, /* disambiguate */
    0, /* print_name */
    0, /* print_data */
    0, /* print_explanation */
    0, /* print_data_returned */
    0, /* data_size */
    0, /* data_type */
    0, /* flags */
    __FILE__,
    __LINE__,
};

#endif /* VIDIOCGCHAN */

/* vim: set ts=8 sw=4 et : */