X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=man%2Fsystemd.socket.xml;h=946c30a757a69390d07abdaf17acc953c7b83a86;hp=22567d483e8804b8a0e67f76ef65a53eb48f930c;hb=3cf148f307e6450aa3411968f59a2563fe9cb154;hpb=916abb21d0a6653e0187b91591e492026886b0a4 diff --git a/man/systemd.socket.xml b/man/systemd.socket.xml index 22567d483..946c30a75 100644 --- a/man/systemd.socket.xml +++ b/man/systemd.socket.xml @@ -9,16 +9,16 @@ 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 . --> @@ -44,18 +44,18 @@ systemd.socket - systemd socket configuration files + Socket unit configuration - systemd.socket + socket.socket Description A unit configuration file whose name ends in - .socket encodes information about + .socket encodes information about an IPC or network socket or a file system FIFO controlled and supervised by systemd, for socket-based activation. @@ -75,25 +75,36 @@ , , and - commands are executed - in. + commands are executed + in, and in + systemd.kill5, + which define the way the processes are terminated, and + in + systemd.resource-control5, + which configure resource control settings for the + processes of the socket. For each socket file a matching service file - (see + must exist, describing the service to start on + incoming traffic on the socket (see systemd.service5 - for details) must exist, describing the service to - start on incoming traffic on the socket. Depending on - the setting of (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 + 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 + option described below. + Depending on the setting of + option described below, this .service unit must either + be named like the .socket unit, but with the suffix + replaced, unless overridden with + ; or it must be a template + unit named the same way. Example: a socket file foo.socket needs a matching service foo.service if is set. If - is set a service template - file foo@.service must exist from - which services are instantiated for each incoming - connection. + is set, a service + template file foo@.service must + exist from which services are instantiated for each + incoming connection. Unless DefaultDependencies= is set to , socket units will @@ -110,9 +121,21 @@ boot or late system shutdown should disable this option. + Socket units will have a + Before= dependency on the service + which they trigger added implicitly. No implicit + WantedBy= or + RequiredBy= 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 Requires= + dependency may be added. + Socket units may be used to implement on-demand starting of services, as well as parallelized starting - of services. + of services. See the blog stories linked at the end + for introduction. Note that the daemon software configured for socket activation with socket units needs to be able @@ -134,75 +157,105 @@ supervises. A number of options that may be used in this section are shared with other unit types. These options are documented in - systemd.exec5. The + systemd.exec5 + and + systemd.kill5. The options specific to the [Socket] section of socket units are the following: - + ListenStream= ListenDatagram= ListenSequentialPacket= Specifies an address to listen on for a stream - (SOCK_STREAM), datagram (SOCK_DGRAM) - resp. sequential packet - (SOCK_SEQPACKET) socket. The address + (SOCK_STREAM), datagram (SOCK_DGRAM), + or sequential packet + (SOCK_SEQPACKET) socket, respectively. The address can be written in various formats: If the address starts with a - slash (/), it is read as file system - socket in the AF_UNIX socket + slash (/), it is read as file system + socket in the AF_UNIX socket family. - 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 + If the address starts with an at + symbol (@), it is read as abstract + namespace socket in the + AF_UNIX + family. The @ is + replaced with a + NUL character + before binding. For details, see unix7. If the address string is a - single number it is read as port - number to listen on for both IPv4 and - IPv6. + single number, it is read as port + number to listen on via + IPv6. Depending on the value of + BindIPv6Only= (see below) this + might result in the service being + available via both IPv6 and IPv4 (default) or + just via IPv6. + 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. If the address string is a - string in the format [x]:y it is read - as IPv6 address x on a port y. - - 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 BindIPv6Only= + setting (see below). + + + Note that SOCK_SEQPACKET (i.e. ListenSequentialPacket=) - is only available for AF_UNIX - sockets. SOCK_STREAM + is only available for AF_UNIX + sockets. SOCK_STREAM (i.e. ListenStream=) when used for IP sockets refers to TCP - sockets, SOCK_DGRAM + sockets, SOCK_DGRAM (i.e. ListenDatagram=) to UDP. 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. - - 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. + + It is also possible to have more + than one socket unit for the same + service when using + Service=, 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. + + 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 FreeBind= option described below. @@ -212,7 +265,7 @@ 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 ListenDatagram= directive above. @@ -223,7 +276,7 @@ Specifies a special file in the file system to listen on. This expects an absolute file - system path as argument. Behaviour + system path as argument. Behavior otherwise is very similar to the ListenFIFO= directive above. Use this to open @@ -238,12 +291,12 @@ Specifies a Netlink family to create a socket for to listen on. This expects a short string - referring to the AF_NETLINK family + referring to the AF_NETLINK family name (such as audit or kobject-uevent) as argument, optionally suffixed by a whitespace followed by a multicast - group integer. Behaviour otherwise is + group integer. Behavior otherwise is very similar to the ListenDatagram= directive above. @@ -254,7 +307,7 @@ Specifies a POSIX message queue name to listen on. This expects a valid message queue name - (i.e. beginning with /). Behaviour + (i.e. beginning with /). Behavior otherwise is very similar to the ListenFIFO= directive above. On Linux message @@ -278,10 +331,13 @@ , they will be accessible via IPv6 only. If (which is the - default, surprise!) the system wide + default, surprise!), the system wide default setting is used, as controlled by - /proc/sys/net/ipv6/bindv6only. + /proc/sys/net/ipv6/bindv6only, + which in turn defaults to the + equivalent of + . @@ -302,7 +358,7 @@ BindToDevice= 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 @@ -318,7 +374,7 @@ DirectoryMode= If listening on a file - system socket of FIFO, the parent + system socket or FIFO, the parent directories are automatically created if needed. This option specifies the file system access mode used when @@ -331,7 +387,7 @@ SocketMode= 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. Takes an access mode in octal @@ -351,17 +407,30 @@ and only one service unit is spawned for all connections (also see above). This value is ignored for - datagram sockets and FIFOs where - a single service unit unconditionally + datagram sockets and FIFOs where a + single service unit unconditionally handles all incoming traffic. Defaults to . For performance reasons, it is recommended to write new daemons only in a way that is suitable for - . This - option is mostly useful to allow - daemons designed for usage with - inetd8, + . A + daemon listening on an AF_UNIX socket + may, but does not need to, call + close2 + on the received socket before + exiting. However, it must not unlink + the socket from a file system. It + should not invoke + shutdown2 + on sockets it got with + Accept=false, but + it may do so for sockets it got with + Accept=true set. + Setting Accept=true + is mostly useful to allow daemons + designed for usage with + inetd8 to work unmodified with systemd socket activation. @@ -376,8 +445,8 @@ are coming in, they will be refused until at least one existing connection is terminated. This setting has no - effect for sockets configured with - or datagram + effect on sockets configured with + or datagram sockets. Defaults to 64. @@ -416,9 +485,9 @@ SendBuffer= 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 + or send buffer sizes of this + socket, respectively. This controls the SO_RCVBUF + and SO_SNDBUF socket options (see socket7 for details.). @@ -466,12 +535,43 @@ for details. + + ReusePort= + Takes a boolean + value. If true, allows multiple bind2s + to this TCP or UDP port. This + controls the SO_REUSEPORT socket + option. See + socket7 + for details. + + + + SmackLabel= + SmackLabelIPIn= + SmackLabelIPOut= + Takes a string + value. Controls the extended + attributes + security.SMACK64, + security.SMACK64IPIN + and + security.SMACK64IPOUT, + respectively, i.e. the security label + of the FIFO, or the security label for + the incoming or outgoing connections + of the socket, respectively. See + Smack.txt + for details. + + PipeSize= Takes an integer value. Controls the pipe buffer size of FIFOs configured in this socket - unit. See + unit. See fcntl2 for details. @@ -481,7 +581,7 @@ MessageQueueMessageSize= These two settings take integer values and control the - mq_maxmsg resp. mq_msgsize field when + 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 @@ -506,6 +606,46 @@ address. Defaults to . + + Transparent= + Takes a boolean + value. Controls the IP_TRANSPARENT + socket option. Defaults to + . + + + + Broadcast= + Takes a boolean + value. This controls the SO_BROADCAST + socket option, which allows broadcast + datagrams to be sent from this + socket. Defaults to + . + + + + PassCredentials= + Takes a boolean + value. This controls the SO_PASSCRED + socket option, which allows AF_UNIX sockets to + receive the credentials of the sending + process in an ancillary message. + Defaults to + . + + + + PassSecurity= + Takes a boolean + value. This controls the SO_PASSSEC + socket option, which allows AF_UNIX + sockets to receive the security + context of the sending process in an + ancillary message. Defaults to + . + + TCPCongestion= Takes a string @@ -523,10 +663,10 @@ ExecStartPost= Takes one or more command lines, which are executed - before (resp. after) the listening + before or after the listening sockets/FIFOs are created and - bound. The first token of the command - line must be an absolute file name, + bound, respectively. The first token of the command + line must be an absolute filename, then followed by arguments for the process. Multiple command lines may be specified following the same scheme as @@ -539,9 +679,9 @@ ExecStopPre= ExecStopPost= Additional commands - that are executed before (resp. after) + that are executed before or after the listening sockets/FIFOs are closed - and removed. Multiple command lines + and removed, respectively. Multiple command lines may be specified following the same scheme as used for ExecStartPre= of @@ -561,63 +701,38 @@ will be considered failed and be shut down again. All commands still running, will be terminated forcibly via - SIGTERM, and after another delay of - this time with SIGKILL. (See - below.) + SIGTERM, and after another delay of + this time with SIGKILL. (See + in systemd.kill5.) 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 - 90s. - - - - KillMode= - Specifies how - processes of this socket unit shall be - killed. One of - , - , - . - - This option is mostly equivalent - to the - option of service files. See - systemd.service5 - for details. - - - - KillSignal= - Specifies which signal - to use when killing a process of this - socket. Defaults to SIGTERM. - - - - - SendSIGKILL= - Specifies whether to - send SIGKILL to remaining processes - after a timeout, if the normal - shutdown procedure left processes of - the socket around. Takes a boolean - value. Defaults to "yes". - + logic. Defaults to TimeoutStartSec= from the + manager configuration file. Service= Specifies the service unit name to activate on incoming - traffic. This defaults to the service - that bears the same name as the socket - (ignoring the different suffixes). In - most cases it should not be necessary - to use this option. + traffic. This setting is only allowed + for sockets with + Accept=no. 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. + + Check + systemd.exec5 + and + systemd.kill5 + for more settings. + @@ -627,7 +742,18 @@ systemctl8, systemd.unit5, systemd.exec5, - systemd.service5 + systemd.kill5, + systemd.resource-control5, + systemd.service5, + systemd.directives7 + + + + For more extensive descriptions see the "systemd for Developers" series: + Socket Activation, + Socket Activation, part II, + Converting inetd Services, + Socket Activated Internet Services and OS Containers.