<?xml version='1.0'?> <!--*-nxml-*--> <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> <!-- This file is part of systemd. Copyright 2010 Lennart Poettering systemd 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 2.1 of the License, or (at your option) any later version. systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>. --> <refentry id="sd_is_fifo" xmlns:xi="http://www.w3.org/2001/XInclude"> <refentryinfo> <title>sd_is_fifo</title> <productname>systemd</productname> <authorgroup> <author> <contrib>Developer</contrib> <firstname>Lennart</firstname> <surname>Poettering</surname> <email>lennart@poettering.net</email> </author> </authorgroup> </refentryinfo> <refmeta> <refentrytitle>sd_is_fifo</refentrytitle> <manvolnum>3</manvolnum> </refmeta> <refnamediv> <refname>sd_is_fifo</refname> <refname>sd_is_socket</refname> <refname>sd_is_socket_inet</refname> <refname>sd_is_socket_unix</refname> <refname>sd_is_mq</refname> <refname>sd_is_special</refname> <refpurpose>Check the type of a file descriptor</refpurpose> </refnamediv> <refsynopsisdiv> <funcsynopsis> <funcsynopsisinfo>#include <systemd/sd-daemon.h></funcsynopsisinfo> <funcprototype> <funcdef>int <function>sd_is_fifo</function></funcdef> <paramdef>int <parameter>fd</parameter></paramdef> <paramdef>const char *<parameter>path</parameter></paramdef> </funcprototype> <funcprototype> <funcdef>int <function>sd_is_socket</function></funcdef> <paramdef>int <parameter>fd</parameter></paramdef> <paramdef>int <parameter>family</parameter></paramdef> <paramdef>int <parameter>type</parameter></paramdef> <paramdef>int <parameter>listening</parameter></paramdef> </funcprototype> <funcprototype> <funcdef>int <function>sd_is_socket_inet</function></funcdef> <paramdef>int <parameter>fd</parameter></paramdef> <paramdef>int <parameter>family</parameter></paramdef> <paramdef>int <parameter>type</parameter></paramdef> <paramdef>int <parameter>listening</parameter></paramdef> <paramdef>uint16_t <parameter>port</parameter></paramdef> </funcprototype> <funcprototype> <funcdef>int <function>sd_is_socket_unix</function></funcdef> <paramdef>int <parameter>fd</parameter></paramdef> <paramdef>int <parameter>type</parameter></paramdef> <paramdef>int <parameter>listening</parameter></paramdef> <paramdef>const char *<parameter>path</parameter></paramdef> <paramdef>size_t <parameter>length</parameter></paramdef> </funcprototype> <funcprototype> <funcdef>int <function>sd_is_mq</function></funcdef> <paramdef>int <parameter>fd</parameter></paramdef> <paramdef>const char *<parameter>path</parameter></paramdef> </funcprototype> <funcprototype> <funcdef>int <function>sd_is_special</function></funcdef> <paramdef>int <parameter>fd</parameter></paramdef> <paramdef>const char *<parameter>path</parameter></paramdef> </funcprototype> </funcsynopsis> </refsynopsisdiv> <refsect1> <title>Description</title> <para><function>sd_is_fifo()</function> may be called to check whether the specified file descriptor refers to a FIFO or pipe. If the <parameter>path</parameter> parameter is not <constant>NULL</constant>, it is checked whether the FIFO is bound to the specified file system path.</para> <para><function>sd_is_socket()</function> may be called to check whether the specified file descriptor refers to a socket. If the <parameter>family</parameter> parameter is not <constant>AF_UNSPEC</constant>, it is checked whether the socket is of the specified family (AF_UNIX, <constant>AF_INET</constant>, ...). If the <parameter>type</parameter> parameter is not 0, it is checked whether the socket is of the specified type (<constant>SOCK_STREAM</constant>, <constant>SOCK_DGRAM</constant>, ...). If the <parameter>listening</parameter> parameter is positive, it is checked whether the socket is in accepting mode, i.e. <function>listen()</function> has been called for it. If <parameter>listening</parameter> is 0, it is checked whether the socket is not in this mode. If the parameter is negative, no such check is made. The <parameter>listening</parameter> parameter should only be used for stream sockets and should be set to a negative value otherwise.</para> <para><function>sd_is_socket_inet()</function> is similar to <function>sd_is_socket()</function>, but optionally checks the IPv4 or IPv6 port number the socket is bound to, unless <parameter>port</parameter> is zero. For this call <parameter>family</parameter> must be passed as either <constant>AF_UNSPEC</constant>, <constant>AF_INET</constant>, or <constant>AF_INET6</constant>.</para> <para><function>sd_is_socket_unix()</function> is similar to <function>sd_is_socket()</function> but optionally checks the <constant>AF_UNIX</constant> path the socket is bound to, unless the <parameter>path</parameter> parameter is <constant>NULL</constant>. For normal file system <constant>AF_UNIX</constant> sockets, set the <parameter>length</parameter> parameter to 0. For Linux abstract namespace sockets, set the <parameter>length</parameter> to the size of the address, including the initial 0 byte, and set the <parameter>path</parameter> to the initial 0 byte of the socket address.</para> <para><function>sd_is_mq()</function> may be called to check whether the specified file descriptor refers to a POSIX message queue. If the <parameter>path</parameter> parameter is not <constant>NULL</constant>, it is checked whether the message queue is bound to the specified name.</para> <para><function>sd_is_special()</function> may be called to check whether the specified file descriptor refers to a special file. If the <parameter>path</parameter> parameter is not <constant>NULL</constant>, it is checked whether the file descriptor is bound to the specified file name. Special files in this context are character device nodes and files in <filename>/proc</filename> or <filename>/sys</filename>.</para> </refsect1> <refsect1> <title>Return Value</title> <para>On failure, these calls return a negative errno-style error code. If the file descriptor is of the specified type and bound to the specified address, a positive return value is returned, otherwise zero.</para> </refsect1> <refsect1> <title>Notes</title> <xi:include href="libsystemd-pkgconfig.xml" xpointer="pkgconfig-text"/> <para>Internally, these function use a combination of <filename>fstat()</filename> and <filename>getsockname()</filename> to check the file descriptor type and where it is bound to.</para> </refsect1> <refsect1> <title>See Also</title> <para> <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>, <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>, <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>, <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry> </para> </refsect1> </refentry>