<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
<!-- Generated by HsColour, http://www.cs.york.ac.uk/fp/darcs/hscolour/ -->
<title>src/System/Daemon.hs</title>
<link type='text/css' rel='stylesheet' href='hscolour.css' />
</head>
<body>
<pre><a name="line-1"></a><span class='hs-comment'>{-# LANGUAGE CPP #-}</span>
<a name="line-2"></a><span class='hs-comment'>{-
<a name="line-3"></a>Copyright (C) 2005 John Goerzen <jgoerzen@complete.org>
<a name="line-4"></a>
<a name="line-5"></a>This program is free software; you can redistribute it and/or modify
<a name="line-6"></a>it under the terms of the GNU General Public License as published by
<a name="line-7"></a>the Free Software Foundation; either version 2 of the License, or
<a name="line-8"></a>(at your option) any later version.
<a name="line-9"></a>
<a name="line-10"></a>This program is distributed in the hope that it will be useful,
<a name="line-11"></a>but WITHOUT ANY WARRANTY; without even the implied warranty of
<a name="line-12"></a>MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
<a name="line-13"></a>GNU General Public License for more details.
<a name="line-14"></a>
<a name="line-15"></a>You should have received a copy of the GNU General Public License
<a name="line-16"></a>along with this program; if not, write to the Free Software
<a name="line-17"></a>Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
<a name="line-18"></a>-}</span>
<a name="line-19"></a>
<a name="line-20"></a><span class='hs-comment'>{- |
<a name="line-21"></a> Module : System.Daemon
<a name="line-22"></a> Copyright : Copyright (C) 2005 John Goerzen
<a name="line-23"></a> License : GNU GPL, version 2 or above
<a name="line-24"></a>
<a name="line-25"></a> Maintainer : John Goerzen <jgoerzen@complete.org>
<a name="line-26"></a> Stability : provisional
<a name="line-27"></a> Portability: portable to platforms with POSIX process\/signal tools
<a name="line-28"></a>
<a name="line-29"></a>Tools for writing daemons\/server processes
<a name="line-30"></a>
<a name="line-31"></a>Written by John Goerzen, jgoerzen\@complete.org
<a name="line-32"></a>
<a name="line-33"></a>Please note: Most of this module is not compatible with Hugs.
<a name="line-34"></a>
<a name="line-35"></a>Messages from this module are logged under @System.Daemon@. See
<a name="line-36"></a>'System.Log.Logger' for details.
<a name="line-37"></a>
<a name="line-38"></a>Based on background
<a name="line-39"></a>from <<a href="http://www.erlenstar.demon.co.uk/unix/faq_2.html#SEC16">http://www.erlenstar.demon.co.uk/unix/faq_2.html#SEC16</a>> and
<a name="line-40"></a><<a href="http://www.haskell.org/hawiki/HaskellUnixDaemon">http://www.haskell.org/hawiki/HaskellUnixDaemon</a>>.
<a name="line-41"></a>
<a name="line-42"></a>This module is not available on Windows.
<a name="line-43"></a>-}</span>
<a name="line-44"></a>
<a name="line-45"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>Daemon</span> <span class='hs-layout'>(</span>
<a name="line-46"></a>
<a name="line-47"></a><span class='hs-cpp'>#if !(defined(mingw32_HOST_OS) || defined(mingw32_TARGET_OS) || defined(__MINGW32__))</span>
<a name="line-48"></a> <span class='hs-varid'>detachDaemon</span>
<a name="line-49"></a><span class='hs-cpp'>#endif</span>
<a name="line-50"></a> <span class='hs-layout'>)</span>
<a name="line-51"></a> <span class='hs-keyword'>where</span>
<a name="line-52"></a><span class='hs-cpp'>#if !(defined(mingw32_HOST_OS) || defined(mingw32_TARGET_OS) || defined(__MINGW32__))</span>
<a name="line-53"></a>
<a name="line-54"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>Posix</span><span class='hs-varop'>.</span><span class='hs-conid'>Process</span>
<a name="line-55"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>Posix</span><span class='hs-varop'>.</span><span class='hs-conid'>IO</span>
<a name="line-56"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>Directory</span>
<a name="line-57"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>Log</span><span class='hs-varop'>.</span><span class='hs-conid'>Logger</span>
<a name="line-58"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>Exit</span>
<a name="line-59"></a>
<a name="line-60"></a>
<a name="line-61"></a><a name="trap"></a><span class='hs-definition'>trap</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>IO</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-varid'>a</span>
<a name="line-62"></a><span class='hs-definition'>trap</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>traplogging</span> <span class='hs-str'>"System.Daemon"</span> <span class='hs-conid'>ERROR</span> <span class='hs-str'>"detachDaemon"</span>
<a name="line-63"></a>
<a name="line-64"></a><a name="detachDaemon"></a><span class='hs-comment'>{- | Detach the process from a controlling terminal and run it in the
<a name="line-65"></a>background, handling it with standard Unix deamon semantics.
<a name="line-66"></a>
<a name="line-67"></a>After running this, please note the following side-effects:
<a name="line-68"></a>
<a name="line-69"></a> * The PID of the running process will change
<a name="line-70"></a>
<a name="line-71"></a> * stdin, stdout, and stderr will not work (they'll be set to
<a name="line-72"></a> \/dev\/null)
<a name="line-73"></a>
<a name="line-74"></a> * CWD will be changed to \/
<a name="line-75"></a>
<a name="line-76"></a>I /highly/ suggest running this function before starting any threads.
<a name="line-77"></a>
<a name="line-78"></a>Note that this is not intended for a daemon invoked from inetd(1).
<a name="line-79"></a>-}</span>
<a name="line-80"></a><span class='hs-definition'>detachDaemon</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-81"></a><span class='hs-definition'>detachDaemon</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>trap</span> <span class='hs-varop'>$</span>
<a name="line-82"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>forkProcess</span> <span class='hs-varid'>child1</span>
<a name="line-83"></a> <span class='hs-varid'>exitImmediately</span> <span class='hs-conid'>ExitSuccess</span>
<a name="line-84"></a>
<a name="line-85"></a><a name="child1"></a><span class='hs-definition'>child1</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-86"></a><span class='hs-definition'>child1</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>trap</span> <span class='hs-varop'>$</span>
<a name="line-87"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>createSession</span>
<a name="line-88"></a> <span class='hs-varid'>forkProcess</span> <span class='hs-varid'>child2</span>
<a name="line-89"></a> <span class='hs-varid'>exitImmediately</span> <span class='hs-conid'>ExitSuccess</span>
<a name="line-90"></a>
<a name="line-91"></a><a name="child2"></a><span class='hs-definition'>child2</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-92"></a><span class='hs-definition'>child2</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>trap</span> <span class='hs-varop'>$</span>
<a name="line-93"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>setCurrentDirectory</span> <span class='hs-str'>"/"</span>
<a name="line-94"></a> <span class='hs-varid'>mapM_</span> <span class='hs-varid'>closeFd</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>stdInput</span><span class='hs-layout'>,</span> <span class='hs-varid'>stdOutput</span><span class='hs-layout'>,</span> <span class='hs-varid'>stdError</span><span class='hs-keyglyph'>]</span>
<a name="line-95"></a> <span class='hs-varid'>nullFd</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>openFd</span> <span class='hs-str'>"/dev/null"</span> <span class='hs-conid'>ReadWrite</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>defaultFileFlags</span>
<a name="line-96"></a> <span class='hs-varid'>mapM_</span> <span class='hs-layout'>(</span><span class='hs-varid'>dupTo</span> <span class='hs-varid'>nullFd</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>stdInput</span><span class='hs-layout'>,</span> <span class='hs-varid'>stdOutput</span><span class='hs-layout'>,</span> <span class='hs-varid'>stdError</span><span class='hs-keyglyph'>]</span>
<a name="line-97"></a> <span class='hs-varid'>closeFd</span> <span class='hs-varid'>nullFd</span>
<a name="line-98"></a><span class='hs-cpp'>#endif</span>
</pre></body>
</html>
distrib
>
Fedora
>
14
>
x86_64
>
media
>
updates
>
by-pkgid
>
ec5844e219498f2057da8f8f3070d4a1
>
files
>
288
