Copyright 2010 Lennart Poettering
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- 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.
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- 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/>.
-->
<refnamediv>
<refname>systemd.socket</refname>
- <refpurpose>systemd socket configuration files</refpurpose>
+ <refpurpose>Socket unit configuration</refpurpose>
</refnamediv>
<refsynopsisdiv>
- <para><filename>systemd.socket</filename></para>
+ <para><filename><replaceable>socket</replaceable>.socket</filename></para>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
- <para>A unit configuration file whose name ends in .socket
- encodes information about an IPC or network socket or
- a file system FIFO controlled and supervised by systemd,
- for socket-based activation.</para>
+ <para>A unit configuration file whose name ends in
+ <literal>.socket</literal> encodes information about
+ an IPC or network socket or a file system FIFO
+ controlled and supervised by systemd, for socket-based
+ activation.</para>
<para>This man page lists the configuration options
specific to this unit type. See
in the [Socket] section.</para>
<para>Additional options are listed in
- <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
-
- <para>For each socket file a matching service file (see <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details)
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ which define the execution environment the
+ <option>ExecStartPre=</option>,
+ <option>ExecStartPost=</option>,
+ <option>ExecStopPre=</option> and
+ <option>ExecStopPost=</option> commands are executed
+ in, and in
+ <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ which define the way the processes are terminated, and
+ in
+ <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ which configure resource control settings for the
+ processes of the socket.</para>
+
+ <para>For each socket file, a matching service file
must exist, describing the service to start on
- incoming traffic on the socket. Depending on the
- setting of <option>Accept=</option> (see below) this
- must either be named like the socket unit, but with
- the suffix replaced; or it must be a template file
- named the same way. Example: a socket file
+ incoming traffic on the socket (see
+ <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for more information about .service files). The name
+ of the .service unit is by default the same as the
+ name of the .socket unit, but can be altered with the
+ <option>Service=</option> option described below.
+ Depending on the setting of the <option>Accept=</option>
+ option described below, this .service unit must either
+ be named like the .socket unit, but with the suffix
+ replaced, unless overridden with
+ <option>Service=</option>; or it must be a template
+ unit named the same way. Example: a socket file
<filename>foo.socket</filename> needs a matching
service <filename>foo.service</filename> if
<option>Accept=false</option> is set. If
- <option>Accept=true</option> is set a service template
- file <filename>foo@.service</filename> must exist from
- which services are instantiated for each incoming
- connection.</para>
+ <option>Accept=true</option> is set, a service
+ template file <filename>foo@.service</filename> must
+ exist from which services are instantiated for each
+ incoming connection.</para>
+
+ <para>Unless <varname>DefaultDependencies=</varname>
+ is set to <option>false</option>, socket units will
+ implicitly have dependencies of type
+ <varname>Requires=</varname> and
+ <varname>After=</varname> on
+ <filename>sysinit.target</filename> as well as
+ dependencies of type <varname>Conflicts=</varname> and
+ <varname>Before=</varname> on
+ <filename>shutdown.target</filename>. These ensure
+ that socket units pull in basic system
+ initialization, and are terminated cleanly prior to
+ system shutdown. Only sockets involved with early
+ boot or late system shutdown should disable this
+ option.</para>
+
+ <para>Socket units will have a
+ <varname>Before=</varname> dependency on the service
+ which they trigger added implicitly. No implicit
+ <varname>WantedBy=</varname> or
+ <varname>RequiredBy=</varname> dependency from the
+ socket to the service is added. This means that the
+ service may be started without the socket, in which
+ case it must be able to open sockets by itself. To
+ prevent this, an explicit <varname>Requires=</varname>
+ dependency may be added.</para>
+
+ <para>Socket units may be used to implement on-demand
+ starting of services, as well as parallelized starting
+ of services. See the blog stories linked at the end
+ for an introduction.</para>
+
+ <para>Note that the daemon software configured for
+ socket activation with socket units needs to be able
+ to accept sockets from systemd, either via systemd's
+ native socket passing interface (see
+ <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ for details) or via the traditional
+ <citerefentry><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry>-style
+ socket passing (i.e. sockets passed in via standard input and
+ output, using <varname>StandardInput=socket</varname>
+ in the service file).</para>
</refsect1>
<refsect1>
supervises. A number of options that may be used in
this section are shared with other unit types. These
options are documented in
- <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
- options specific to the [Socket] section of service
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ and
+ <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
+ options specific to the [Socket] section of socket
units are the following:</para>
- <variablelist>
+ <variablelist class='unit-directives'>
<varlistentry>
<term><varname>ListenStream=</varname></term>
<term><varname>ListenDatagram=</varname></term>
<term><varname>ListenSequentialPacket=</varname></term>
<listitem><para>Specifies an address
to listen on for a stream
- (SOCK_STREAM), datagram (SOCK_DGRAM)
- resp. sequential packet
- (SOCK_SEQPACKET) socket. The address
+ (<constant>SOCK_STREAM</constant>), datagram (<constant>SOCK_DGRAM</constant>),
+ or sequential packet
+ (<constant>SOCK_SEQPACKET</constant>) socket, respectively. The address
can be written in various formats:</para>
<para>If the address starts with a
- slash (/), it is read as file system
- socket in the AF_UNIX socket
+ slash (<literal>/</literal>), it is read as file system
+ socket in the <constant>AF_UNIX</constant> socket
family.</para>
- <para>If the address starts with an
- ampersand (@) it is read as abstract
- namespace socket in the AF_UNIX
- family. The @ is replaced with a NUL
- character before binding. For details
- see
+ <para>If the address starts with an at
+ symbol (<literal>@</literal>), it is read as abstract
+ namespace socket in the
+ <constant>AF_UNIX</constant>
+ family. The <literal>@</literal> is
+ replaced with a
+ <constant>NUL</constant> character
+ before binding. For details, see
<citerefentry><refentrytitle>unix</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
<para>If the address string is a
- single number it is read as port
- number to listen on for both IPv4 and
- IPv6.</para>
+ single number, it is read as port
+ number to listen on via
+ IPv6. Depending on the value of
+ <varname>BindIPv6Only=</varname> (see below) this
+ might result in the service being
+ available via both IPv6 and IPv4 (default) or
+ just via IPv6.
+ </para>
<para>If the address string is a
- string in the format v.w.x.y:z it is
+ string in the format v.w.x.y:z, it is
read as IPv4 specifier for listening
on an address v.w.x.y on a port
z.</para>
<para>If the address string is a
- string in the format [x]:y it is read
- as IPv6 address x on a port y.</para>
-
- <para>Note that SOCK_SEQPACKET
+ string in the format [x]:y, it is read
+ as IPv6 address x on a port y. Note
+ that this might make the service
+ available via IPv4, too, depending on
+ the <varname>BindIPv6Only=</varname>
+ setting (see below).
+ </para>
+
+ <para>Note that <constant>SOCK_SEQPACKET</constant>
(i.e. <varname>ListenSequentialPacket=</varname>)
- is only available for AF_UNIX
- sockets. SOCK_STREAM
+ is only available for <constant>AF_UNIX</constant>
+ sockets. <constant>SOCK_STREAM</constant>
(i.e. <varname>ListenStream=</varname>)
when used for IP sockets refers to TCP
- sockets, SOCK_DGRAM
+ sockets, <constant>SOCK_DGRAM</constant>
(i.e. <varname>ListenDatagram=</varname>)
to UDP.</para>
<para>These options may be specified
more than once in which case incoming
- traffic on any of the sockets will trigger
- service activation, and all listed
- sockets will be passed to the service,
- regardless whether there is incoming
- traffic on them or not.</para>
-
- <para>If an IP address is used here it
- is often desirable to listen on it
+ traffic on any of the sockets will
+ trigger service activation, and all
+ listed sockets will be passed to the
+ service, regardless of whether there is
+ incoming traffic on them or not. If
+ the empty string is assigned to any of
+ these options, the list of addresses
+ to listen on is reset, all prior uses
+ of any of these options will have no
+ effect.</para>
+
+ <para>It is also possible to have more
+ than one socket unit for the same
+ service when using
+ <varname>Service=</varname>, and the
+ service will receive all the sockets
+ configured in all the socket units.
+ Sockets configured in one unit are
+ passed in the order of configuration,
+ but no ordering between socket units
+ is specified.</para>
+
+ <para>If an IP address is used here,
+ it is often desirable to listen on it
before the interface it is configured
on is up and running, and even
- regardless whether it will be up and
- running ever at all. To deal with this it is
- recommended to set the
+ regardless of whether it will be up and
+ running at any point. To deal with this,
+ it is recommended to set the
<varname>FreeBind=</varname> option
described below.</para></listitem>
</varlistentry>
<listitem><para>Specifies a file
system FIFO to listen on. This expects
an absolute file system path as
- argument. Behaviour otherwise is very
+ argument. Behavior otherwise is very
similar to the
<varname>ListenDatagram=</varname>
directive above.</para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><varname>ListenSpecial=</varname></term>
+ <listitem><para>Specifies a special
+ file in the file system to listen
+ on. This expects an absolute file
+ system path as argument. Behavior
+ otherwise is very similar to the
+ <varname>ListenFIFO=</varname>
+ directive above. Use this to open
+ character device nodes as well as
+ special files in
+ <filename>/proc</filename> and
+ <filename>/sys</filename>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>ListenNetlink=</varname></term>
+ <listitem><para>Specifies a Netlink
+ family to create a socket for to
+ listen on. This expects a short string
+ referring to the <constant>AF_NETLINK</constant> family
+ name (such as <varname>audit</varname>
+ or <varname>kobject-uevent</varname>)
+ as argument, optionally suffixed by a
+ whitespace followed by a multicast
+ group integer. Behavior otherwise is
+ very similar to the
+ <varname>ListenDatagram=</varname>
+ directive above.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>ListenMessageQueue=</varname></term>
+ <listitem><para>Specifies a POSIX
+ message queue name to listen on. This
+ expects a valid message queue name
+ (i.e. beginning with /). Behavior
+ otherwise is very similar to the
+ <varname>ListenFIFO=</varname>
+ directive above. On Linux message
+ queue descriptors are actually file
+ descriptors and can be inherited
+ between processes.</para></listitem>
+ </varlistentry>
+
<varlistentry>
<term><varname>BindIPv6Only=</varname></term>
<listitem><para>Takes a one of
<option>ipv6-only</option>, they will
be accessible via IPv6 only. If
<option>default</option> (which is the
- default, surprise!) the system wide
+ default, surprise!), the system wide
default setting is used, as controlled
by
- <filename>/proc/sys/net/ipv6/bindv6only</filename>.</para>
+ <filename>/proc/sys/net/ipv6/bindv6only</filename>,
+ which in turn defaults to the
+ equivalent of
+ <option>both</option>.</para>
</listitem>
</varlistentry>
<term><varname>BindToDevice=</varname></term>
<listitem><para>Specifies a network
interface name to bind this socket
- to. If set traffic will only be
+ to. If set, traffic will only be
accepted from the specified network
interfaces. This controls the
SO_BINDTODEVICE socket option (see
<citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
- for details). If this option is used
+ for details). If this option is used,
an automatic dependency from this
socket unit on the network interface
device unit
</varlistentry>
<varlistentry>
- <term><varname>DirectoryMode=</varname></term>
- <listitem><para>If listening on a file
- system socket of FIFO the parent
- directories are automatically created
- if needed. This option specifies the
- file system access mode used when
- creating these directories. Defaults
- to 0755.</para></listitem>
+ <term><varname>SocketUser=</varname></term>
+ <term><varname>SocketGroup=</varname></term>
+
+ <listitem><para>Takes a UNIX
+ user/group name. When specified,
+ all AF_UNIX sockets and FIFO nodes in
+ the file system are owned by the
+ specified user and group. If unset
+ (the default), the nodes are owned by
+ the root user/group (if run in system
+ context) or the invoking user/group
+ (if run in user context). If only a
+ user is specified but no group, then
+ the group is derived from the user's
+ default group.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>SocketMode=</varname></term>
<listitem><para>If listening on a file
- system socket of FIFO this option
+ system socket or FIFO, this option
specifies the file system access mode
used when creating the file
- node. Defaults to
+ node. Takes an access mode in octal
+ notation. Defaults to
0666.</para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><varname>DirectoryMode=</varname></term>
+ <listitem><para>If listening on a file
+ system socket or FIFO, the parent
+ directories are automatically created
+ if needed. This option specifies the
+ file system access mode used when
+ creating these directories. Takes an
+ access mode in octal
+ notation. Defaults to
+ 0755.</para></listitem>
+ </varlistentry>
+
<varlistentry>
<term><varname>Accept=</varname></term>
<listitem><para>Takes a boolean
- argument. If true a service instance
+ argument. If true, a service instance
is spawned for each incoming
connection and only the connection
- socket is passed to it. If false all
+ socket is passed to it. If false, all
listening sockets themselves are
passed to the started service unit,
and only one service unit is spawned
for all connections (also see
above). This value is ignored for
- datagram sockets and FIFOs where
- unconditionally a single service unit
+ datagram sockets and FIFOs where a
+ single service unit unconditionally
handles all incoming traffic. Defaults
to <option>false</option>. For
- performance reasons it is recommended
+ performance reasons, it is recommended
to write new daemons only in a way
that is suitable for
- <option>Accept=false</option>. This
- option is mostly useful to allow
- daemons designed for usage with
+ <option>Accept=false</option>. A
+ daemon listening on an <constant>AF_UNIX</constant> socket
+ may, but does not need to, call
+ <citerefentry><refentrytitle>close</refentrytitle><manvolnum>2</manvolnum></citerefentry>
+ on the received socket before
+ exiting. However, it must not unlink
+ the socket from a file system. It
+ should not invoke
+ <citerefentry><refentrytitle>shutdown</refentrytitle><manvolnum>2</manvolnum></citerefentry>
+ on sockets it got with
+ <varname>Accept=false</varname>, but
+ it may do so for sockets it got with
+ <varname>Accept=true</varname> set.
+ Setting <varname>Accept=true</varname>
+ is mostly useful to allow daemons
+ designed for usage with
<citerefentry><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- to work unmodified with system socket
+ to work unmodified with systemd socket
activation.</para></listitem>
</varlistentry>
services instances for, when
<option>Accept=true</option> is
set. If more concurrent connections
- are coming in they will be refused,
+ are coming in, they will be refused
until at least one existing connection
is terminated. This setting has no
- effect for sockets configured with
- <option>Accept=no</option> or datagram
+ effect on sockets configured with
+ <option>Accept=false</option> or datagram
sockets. Defaults to
64.</para></listitem>
</varlistentry>
<term><varname>ReceiveBuffer=</varname></term>
<term><varname>SendBuffer=</varname></term>
<listitem><para>Takes an integer
- argument controlling the receive
- resp. send buffer sizes of this
- socket. This controls the SO_RCVBUF
- resp. SO_SNDBUF socket options (see
+ argument controlling the receive or
+ send buffer sizes of this socket,
+ respectively. This controls the
+ SO_RCVBUF and SO_SNDBUF socket options
+ (see
<citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
- for details.).</para></listitem>
+ for details.). The usual suffixes K,
+ M, G are supported and are understood
+ to the base of 1024.</para></listitem>
</varlistentry>
<varlistentry>
for details.</para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><varname>ReusePort=</varname></term>
+ <listitem><para>Takes a boolean
+ value. If true, allows multiple <citerefentry><refentrytitle>bind</refentrytitle><manvolnum>2</manvolnum></citerefentry>s
+ to this TCP or UDP port. This
+ controls the SO_REUSEPORT socket
+ option. See
+ <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+ for details.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>SmackLabel=</varname></term>
+ <term><varname>SmackLabelIPIn=</varname></term>
+ <term><varname>SmackLabelIPOut=</varname></term>
+ <listitem><para>Takes a string
+ value. Controls the extended
+ attributes
+ <literal>security.SMACK64</literal>,
+ <literal>security.SMACK64IPIN</literal>
+ and
+ <literal>security.SMACK64IPOUT</literal>,
+ respectively, i.e. the security label
+ of the FIFO, or the security label for
+ the incoming or outgoing connections
+ of the socket, respectively. See
+ <ulink
+ url="https://www.kernel.org/doc/Documentation/security/Smack.txt">Smack.txt</ulink>
+ for details.</para></listitem>
+ </varlistentry>
+
<varlistentry>
<term><varname>PipeSize=</varname></term>
- <listitem><para>Takes an integer
- value. Controls the pipe buffer size
+ <listitem><para>Takes a size in
+ bytes. Controls the pipe buffer size
of FIFOs configured in this socket
- unit. See
+ unit. See
<citerefentry><refentrytitle>fcntl</refentrytitle><manvolnum>2</manvolnum></citerefentry>
+ for details. The usual suffixes K, M,
+ G are supported and are understood to
+ the base of 1024.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>MessageQueueMaxMessages=</varname>,
+ <varname>MessageQueueMessageSize=</varname></term>
+ <listitem><para>These two settings
+ take integer values and control the
+ mq_maxmsg field or the mq_msgsize field, respectively, when
+ creating the message queue. Note that
+ either none or both of these variables
+ need to be set. See
+ <citerefentry><refentrytitle>mq_setattr</refentrytitle><manvolnum>3</manvolnum></citerefentry>
for details.</para></listitem>
</varlistentry>
address. Defaults to <option>false</option>.</para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><varname>Transparent=</varname></term>
+ <listitem><para>Takes a boolean
+ value. Controls the IP_TRANSPARENT
+ socket option. Defaults to
+ <option>false</option>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>Broadcast=</varname></term>
+ <listitem><para>Takes a boolean
+ value. This controls the SO_BROADCAST
+ socket option, which allows broadcast
+ datagrams to be sent from this
+ socket. Defaults to
+ <option>false</option>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>PassCredentials=</varname></term>
+ <listitem><para>Takes a boolean
+ value. This controls the SO_PASSCRED
+ socket option, which allows <constant>AF_UNIX</constant> sockets to
+ receive the credentials of the sending
+ process in an ancillary message.
+ Defaults to
+ <option>false</option>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>PassSecurity=</varname></term>
+ <listitem><para>Takes a boolean
+ value. This controls the SO_PASSSEC
+ socket option, which allows <constant>AF_UNIX</constant>
+ sockets to receive the security
+ context of the sending process in an
+ ancillary message. Defaults to
+ <option>false</option>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>TCPCongestion=</varname></term>
+ <listitem><para>Takes a string
+ value. Controls the TCP congestion
+ algorithm used by this socket. Should
+ be one of "westwood", "veno", "cubic",
+ "lp" or any other available algorithm
+ supported by the IP stack. This
+ setting applies only to stream
+ sockets.</para></listitem>
+ </varlistentry>
+
<varlistentry>
<term><varname>ExecStartPre=</varname></term>
<term><varname>ExecStartPost=</varname></term>
- <listitem><para>Takes a command line
- that is executed before (resp. after)
- the listening sockets/FIFOs are created and
- bound. The first token of the command
- line must be an absolute file name,
+ <listitem><para>Takes one or more
+ command lines, which are executed
+ before or after the listening
+ sockets/FIFOs are created and
+ bound, respectively. The first token of the command
+ line must be an absolute filename,
then followed by arguments for the
- process. If specified more than once,
- all commands are executed one after
- the other, serially. Use of these
- settings is optional.</para></listitem>
+ process. Multiple command lines may be
+ specified following the same scheme as
+ used for
+ <varname>ExecStartPre=</varname> of
+ service unit files.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>ExecStopPre=</varname></term>
<term><varname>ExecStopPost=</varname></term>
<listitem><para>Additional commands
- that are executed before (resp. after)
+ that are executed before or after
the listening sockets/FIFOs are closed
- and removed. If specified more than
- once, all commands are executed one
- after the other, serially. Use of
- these settings is
- optional.</para></listitem>
+ and removed, respectively. Multiple command lines
+ may be specified following the same
+ scheme as used for
+ <varname>ExecStartPre=</varname> of
+ service unit files.</para></listitem>
</varlistentry>
<varlistentry>
<varname>ExecStartPost=</varname>,
<varname>ExecStopPre=</varname> and
<varname>ExecStopPost=</varname> to
- finish. If a comand does not exit
- within the configured time the socket
+ finish. If a command does not exit
+ within the configured time, the socket
will be considered failed and be shut
- down again. All commands still running
+ down again. All commands still running,
will be terminated forcibly via
- SIGTERM, and after another delay of
- this time with SIGKILL. (See
- <option>KillMode=</option> below.)
+ <constant>SIGTERM</constant>, and after another delay of
+ this time with <constant>SIGKILL</constant>. (See
+ <option>KillMode=</option> in <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>.)
Takes a unit-less value in seconds, or
a time span value such as "5min
20s". Pass 0 to disable the timeout
- logic. Defaults to
- 60s.</para></listitem>
+ logic. Defaults to <varname>TimeoutStartSec=</varname> from the
+ manager configuration file.</para></listitem>
</varlistentry>
<varlistentry>
- <term><varname>KillMode=</varname></term>
- <listitem><para>Specifies how
- processes of this socket unit shall be
- killed. One of
- <option>control-group</option>,
- <option>process-group</option>,
- <option>process</option>,
- <option>none</option>.</para>
+ <term><varname>Service=</varname></term>
+ <listitem><para>Specifies the service
+ unit name to activate on incoming
+ traffic. This setting is only allowed
+ for sockets with
+ <varname>Accept=no</varname>. It
+ defaults to the service that bears the
+ same name as the socket (with the
+ suffix replaced). In most cases, it
+ should not be necessary to use this
+ option.</para></listitem>
+ </varlistentry>
- <para>This option is mostly equivalent
- to the <option>KillMode=</option>
- option of service files. See
- <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- for details.</para></listitem>
+ <varlistentry>
+ <term><varname>RemoveOnStop=</varname></term>
+ <listitem><para>Takes a boolean
+ argument. If enabled, any file nodes
+ created by this socket unit are
+ removed when it is stopped. This
+ applies to AF_UNIX sockets in the file
+ system, POSIX message queues, FIFOs,
+ as well as any symlinks to
+ them configured with
+ <varname>Symlinks=</varname>. Normally,
+ it should not be necessary to use this
+ option, and is not recommended as
+ services might continue to run after
+ the socket unit has been terminated
+ and it should still be possible to
+ communicate with them via their file
+ system node. Defaults to
+ off.</para></listitem>
</varlistentry>
+
+ <varlistentry>
+ <term><varname>Symlinks=</varname></term>
+ <listitem><para>Takes a list of file
+ system paths. The specified paths will
+ be created as symlinks to the AF_UNIX
+ socket path or FIFO path of this
+ socket unit. If this setting is used,
+ only one AF_UNIX socket in the file
+ system or one FIFO may be configured
+ for the socket unit. Use this option
+ to manage one or more symlinked alias
+ names for a socket, binding their
+ lifecycle together. Defaults to the
+ empty list.</para></listitem>
+ </varlistentry>
+
</variablelist>
+
+ <para>Check
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ and
+ <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for more settings.</para>
+
</refsect1>
<refsect1>
<title>See Also</title>
<para>
- <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+ </para>
+
+ <para>
+ For more extensive descriptions see the "systemd for Developers" series:
+ <ulink url="http://0pointer.de/blog/projects/socket-activation.html">Socket Activation</ulink>,
+ <ulink url="http://0pointer.de/blog/projects/socket-activation2.html">Socket Activation, part II</ulink>,
+ <ulink url="http://0pointer.de/blog/projects/inetd.html">Converting inetd Services</ulink>,
+ <ulink url="http://0pointer.de/blog/projects/socket-activated-containers.html">Socket Activated Internet Services and OS Containers</ulink>.
</para>
</refsect1>
~ianmdlvl / elogind.git / blobdiff