<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>
<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. If the
<parameter>family</parameter> parameter is not
- <constant>AF_UNSPEC</constant> it is checked whether
+ <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
+ <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
+ <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
<constant>AF_INET6</constant>.</para>
<para><function>sd_is_socket_unix()</function> is
- similar to <function>sd_is_socket()</function>, but
+ 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
+ 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 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>
<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
+ they implement are simple, and they can easily be
reimplemented in daemons if it is important to support
this interface without using the reference
implementation.</para>
<filename>getsockname()</filename> to check the file
descriptor type and where it is bound to.</para>
- <para>For details about the algorithms check the
+ <para>For details about the algorithms, check the
liberally licensed reference implementation sources:
<ulink url="http://cgit.freedesktop.org/systemd/systemd/plain/src/libsystemd-daemon/sd-daemon.c"/>
and <ulink
<filename>sd-daemon.h</filename> files. These
interfaces are available as shared library, which can
be compiled and linked to with the
- <constant>libsystemd-daemon</constant>
- <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ <constant>libsystemd-daemon</constant> <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
~ianmdlvl / elogind.git / blobdiff