libexplain/buffer/errno/getgroups.c

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/*
 * libexplain - Explain errno values returned by libc functions
 * Copyright (C) 2009, 2010, 2013 Peter Miller
 *
 * 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/limits.h> /* for NGROUPS_MAX on Solaris */
#include <libexplain/ac/unistd.h>

#include <libexplain/buffer/efault.h>
#include <libexplain/buffer/einval.h>
#include <libexplain/buffer/errno/generic.h>
#include <libexplain/buffer/errno/getgroups.h>
#include <libexplain/buffer/pointer.h>
#include <libexplain/explanation.h>
#include <libexplain/option.h>


static void
explain_buffer_errno_getgroups_system_call(explain_string_buffer_t *sb, int
    errnum, int data_size, gid_t *data)
{
    (void)errnum;
    explain_string_buffer_puts(sb, "getgroups(data_size = ");
    explain_string_buffer_printf(sb, "%d", data_size);
    explain_string_buffer_puts(sb, ", data = ");
    explain_buffer_pointer(sb, data);
    explain_string_buffer_putc(sb, ')');
}


static void
explain_buffer_errno_getgroups_explanation(explain_string_buffer_t *sb,
    int errnum, int data_size, gid_t *data)
{
    /*
     * http://www.opengroup.org/onlinepubs/009695399/functions/getgroups.html
     */
    (void)data;
    switch (errnum)
    {
    case EFAULT:
        explain_buffer_efault(sb, "data");
        break;

    case EINVAL:
        explain_buffer_einval_too_small(sb, "data_size", data_size);
        if (data_size >= 0 && explain_option_dialect_specific())
        {
            gid_t groups[NGROUPS_MAX];
            int ngroups;

            ngroups = getgroups(NGROUPS_MAX, groups);
            if (ngroups >= 0 && data_size < ngroups)
            {
                explain_string_buffer_printf
                (
                    sb,
                    " (%d < %d)",
                    data_size,
                    ngroups
                );
            }
        }
        break;

    default:
        explain_buffer_errno_generic(sb, errnum, "getgroups");
        break;
    }
}


void
explain_buffer_errno_getgroups(explain_string_buffer_t *sb, int errnum, int
    data_size, gid_t *data)
{
    explain_explanation_t exp;

    explain_explanation_init(&exp, errnum);
    explain_buffer_errno_getgroups_system_call(&exp.system_call_sb, errnum,
        data_size, data);
    explain_buffer_errno_getgroups_explanation(&exp.explanation_sb, errnum,
        data_size, data);
    explain_explanation_assemble(&exp, sb);
}


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