fdmisc.c

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/*
 *  OpenVPN -- An application to securely tunnel IP networks
 *             over a single UDP port, with support for SSL/TLS-based
 *             session authentication and key exchange,
 *             packet encryption, packet authentication, and
 *             packet compression.
 *
 *  Copyright (C) 2002-2026 OpenVPN Inc <sales@openvpn.net>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, see <https://www.gnu.org/licenses/>.
 */
 
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
 
#include "syshead.h"
 
#include "fdmisc.h"
#include "error.h"
 
#include "memdbg.h"
 
#if defined(_WIN32) && (defined(__GNUC__) || defined(__clang__))
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wsign-conversion"
#endif
 
/* Set a file descriptor to non-blocking */
bool
set_nonblock_action(socket_descriptor_t fd)
{
#ifdef _WIN32
    u_long arg = 1;
    if (ioctlsocket(fd, FIONBIO, &arg))
    {
        return false;
    }
#else /* ifdef _WIN32 */
    if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0)
    {
        return false;
    }
#endif
    return true;
}
 
#if defined(_WIN32) && (defined(__GNUC__) || defined(__clang__))
#pragma GCC diagnostic pop
#endif
 
/* Set a file descriptor to not be passed across execs */
bool
set_cloexec_action(socket_descriptor_t fd)
{
#ifndef _WIN32
    if (fcntl(fd, F_SETFD, FD_CLOEXEC) < 0)
    {
        return false;
    }
#endif
    return true;
}
 
/* Set a file descriptor to non-blocking */
void
set_nonblock(socket_descriptor_t fd)
{
    if (!set_nonblock_action(fd))
    {
        msg(M_ERR, "Set socket to non-blocking mode failed");
    }
}
 
/* Set a file descriptor to not be passed across execs */
void
set_cloexec(socket_descriptor_t fd)
{
    if (!set_cloexec_action(fd))
    {
        msg(M_ERR, "Set FD_CLOEXEC flag on file descriptor failed");
    }
}