Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
+ 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
- General Public License for more details.
+ Lesser General Public License for more details.
- You should have received a copy of the GNU General Public License
+ You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<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 "sd-daemon.h"</funcsynopsisinfo>
+ <funcsynopsisinfo>#include <systemd/sd-daemon.h></funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_is_fifo</function></funcdef>
<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>
<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 NULL, it is checked whether the FIFO
- is bound to the specified file system path.</para>
+ 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. It the
+ refers to a socket. If the
<parameter>family</parameter> parameter is not
- AF_UNSPEC it is checked whether the socket is of the
- specified family (AF_UNIX, AF_INET, ...). If the
- <parameter>type</parameter> parameter is not 0 it is
+ <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
- (SOCK_STREAM, SOCK_DGRAM, ...). If the
- <parameter>listening</parameter> parameter is positive
+ (<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
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 AF_UNSPEC, AF_INET or
- AF_INET6.</para>
+ 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 AF_UNIX path the socket is bound
+ 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 NULL. For normal file system AF_UNIX sockets set
- the <parameter>length</parameter> parameter to 0. For
- Linux abstract namespace sockets set the
+ 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
+ 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 NULL, it
- is checked whether the message queue is bound to the
- specified name.</para>
+ <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>
<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
+ the specified type and bound to the specified address,
a positive return value is returned, otherwise
zero.</para>
</refsect1>
<refsect1>
<title>Notes</title>
- <para>These functions are provided by the reference
- implementation of APIs for new-style daemons and
- distributed with the systemd package. The algorithms
- they implement are simple, and can easily be
- reimplemented in daemons if it is important to support
- this interface without using the reference
- implementation.</para>
+ <para>These APIs are implemented as a shared library,
+ which can be compiled and linked to with the
+ <constant>libsystemd</constant> <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ file.</para>
<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>
-
- <para>For details about the algorithms check the
- liberally licensed reference implementation sources:
- <ulink url="http://cgit.freedesktop.org/systemd/tree/src/sd-daemon.c"/>
- resp. <ulink
- url="http://cgit.freedesktop.org/systemd/tree/src/sd-daemon.h"/></para>
-
- <para><function>sd_is_fifo()</function> and the
- related functions are implemented in the reference
- implementation's <filename>sd-daemon.c</filename> and
- <filename>sd-daemon.h</filename> files. These
- interfaces are available as shared library, which can
- be compiled and linked to with the
- <literal>libsystemd-daemon</literal>
- <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
- file. Alternatively, applications consuming these APIs
- may copy the implementation into their source
- tree. For more details about the reference
- implementation see
- <citerefentry><refentrytitle>sd_daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
-
- <para>These functions continue to work as described,
- even if -DDISABLE_SYSTEMD is set during
- compilation.</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>7</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>
~ianmdlvl / elogind.git / blobdiff