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diff --git a/man/sd_listen_fds.xml b/man/sd_listen_fds.xml deleted file mode 100644 index b891b6b039..0000000000 --- a/man/sd_listen_fds.xml +++ /dev/null @@ -1,204 +0,0 @@ -<?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_listen_fds"> - - <refentryinfo> - <title>sd_listen_fds</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_listen_fds</refentrytitle> - <manvolnum>3</manvolnum> - </refmeta> - - <refnamediv> - <refname>sd_listen_fds</refname> - <refname>SD_LISTEN_FDS_START</refname> - <refpurpose>Check for file descriptors passed by the system manager</refpurpose> - </refnamediv> - - <refsynopsisdiv> - <funcsynopsis> - <funcsynopsisinfo>#include <systemd/sd-daemon.h></funcsynopsisinfo> - - <funcsynopsisinfo>#define SD_LISTEN_FDS_START 3</funcsynopsisinfo> - - <funcprototype> - <funcdef>int <function>sd_listen_fds</function></funcdef> - <paramdef>int <parameter>unset_environment</parameter></paramdef> - </funcprototype> - </funcsynopsis> - </refsynopsisdiv> - - <refsect1> - <title>Description</title> - - <para><function>sd_listen_fds()</function> shall be - called by a daemon to check for file descriptors - passed by the init system as part of the socket-based - activation logic.</para> - - <para>If the <parameter>unset_environment</parameter> - parameter is non-zero - <function>sd_listen_fds()</function> will unset the - <varname>$LISTEN_FDS</varname>/<varname>$LISTEN_PID</varname> - environment variables before returning (regardless - whether the function call itself succeeded or - not). Further calls to - <function>sd_listen_fds()</function> will then fail, - but the variables are no longer inherited by child - processes.</para> - - <para>If a daemon receives more than one file - descriptor, they will be passed in the same order as - configured in the systemd socket definition - file. Nonetheless it is recommended to verify the - correct socket types before using them. To simplify - this checking the functions - <citerefentry><refentrytitle>sd_is_fifo</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_is_socket</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_is_socket_inet</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_is_socket_unix</refentrytitle><manvolnum>3</manvolnum></citerefentry> - are provided. In order to maximize flexibility it is - recommended to make these checks as loose as possible - without allowing incorrect setups. i.e. often the - actual port number a socket is bound to matters little - for the service to work, hence it should not be - verified. On the other hand, whether a socket is a - datagram or stream socket matters a lot for the most - common program logics and should be checked.</para> - - <para>This function call will set the FD_CLOEXEC flag - for all passed file descriptors to avoid further - inheritance to children of the calling process.</para> - </refsect1> - - <refsect1> - <title>Return Value</title> - - <para>On failure, this call returns a negative - errno-style error code. If - <varname>$LISTEN_FDS</varname>/<varname>$LISTEN_PID</varname> - was not set or was not correctly set for this daemon and - hence no file descriptors were received, 0 is - returned. Otherwise the number of file descriptors - passed is returned. The application may find them - starting with file descriptor SD_LISTEN_FDS_START, - i.e. file descriptor 3.</para> - </refsect1> - - <refsect1> - <title>Notes</title> - - <para>This function is provided by the reference - implementation of APIs for new-style daemons and - distributed with the systemd package. The algorithm it - implements is simple, and can easily be reimplemented - in daemons if it is important to support this - interface without using the reference - implementation.</para> - - <para>Internally, this function checks whether the - <varname>$LISTEN_PID</varname> environment variable - equals the daemon PID. If not, it returns - immediately. Otherwise it parses the number passed in - the <varname>$LISTEN_FDS</varname> environment - variable, then sets the FD_CLOEXEC flag for the parsed - number of file descriptors starting from - SD_LISTEN_FDS_START. Finally it returns the parsed - number.</para> - - <para>For details about the algorithm check the - liberally licensed reference implementation sources: - <ulink url="http://cgit.freedesktop.org/systemd/systemd/plain/src/libsystemd-daemon/sd-daemon.c"/> - and <ulink - url="http://cgit.freedesktop.org/systemd/systemd/plain/src/systemd/sd-daemon.h"/></para> - - <para><function>sd_listen_fds()</function> is - 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>3</manvolnum></citerefentry>.</para> - - <para>If the reference implementation is used as - drop-in files and -DDISABLE_SYSTEMD is set during - compilation this function will always return 0 and - otherwise become a NOP.</para> - </refsect1> - - <refsect1> - <title>Environment</title> - - <variablelist> - <varlistentry> - <term><varname>$LISTEN_PID</varname></term> - <term><varname>$LISTEN_FDS</varname></term> - - <listitem><para>Set by the init system - for supervised processes that use - socket-based activation. This - environment variable specifies the - data - <function>sd_listen_fds()</function> - parses. See above for - details.</para></listitem> - </varlistentry> - </variablelist> - </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_is_fifo</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_is_socket</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_is_socket_inet</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>sd_is_socket_unix</refentrytitle><manvolnum>3</manvolnum></citerefentry>, - <citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>, - <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>, - <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry> - </para> - </refsect1> - -</refentry> |