From 6470e6cc2588b448d7605b4769cb8add5bb13a3c Mon Sep 17 00:00:00 2001
From: Badlop <badlop@process-one.net>
Date: Mon, 24 Aug 2009 21:21:39 +0000
Subject: [PATCH] Write PID file, path is configurable in ejabberdctl.cfg
 (EJAB-1023)

SVN Revision: 2527
---
 doc/guide.html              |  2 ++
 doc/guide.tex               |  2 ++
 src/ejabberd.erl            | 12 ++++++++++++
 src/ejabberd_app.erl        | 33 +++++++++++++++++++++++++++++++++
 src/ejabberdctl.cfg.example | 12 ++++++++++++
 src/ejabberdctl.template    |  1 +
 6 files changed, 62 insertions(+)

diff --git a/doc/guide.html b/doc/guide.html
index 6b4be6e3a..02c5c94cd 100644
--- a/doc/guide.html
+++ b/doc/guide.html
@@ -3280,6 +3280,8 @@ all the environment variables and command line parameters.</P><P>The environment
 	Path to the directory with binary system libraries.
 </DD><DT CLASS="dt-description"><B><TT>EJABBERD_DOC_PATH</TT></B></DT><DD CLASS="dd-description">
 	Path to the directory with ejabberd documentation.
+</DD><DT CLASS="dt-description"><B><TT>EJABBERD_PID_PATH</TT></B></DT><DD CLASS="dd-description">
+	Path to the PID file that ejabberd can create when started.
 </DD><DT CLASS="dt-description"><B><TT>HOME</TT></B></DT><DD CLASS="dd-description">
 	Path to the directory that is considered <TT>ejabberd</TT>&#X2019;s home.
 	This path is used to read the file <TT>.erlang.cookie</TT>.
diff --git a/doc/guide.tex b/doc/guide.tex
index 43110aad9..74d6fa8b4 100644
--- a/doc/guide.tex
+++ b/doc/guide.tex
@@ -4210,6 +4210,8 @@ The environment variables:
 	Path to the directory with binary system libraries.
   \titem{EJABBERD\_DOC\_PATH}
 	Path to the directory with ejabberd documentation.
+  \titem{EJABBERD\_PID\_PATH}
+	Path to the PID file that ejabberd can create when started.
   \titem{HOME}
 	Path to the directory that is considered \ejabberd{}'s home.
 	This path is used to read the file \term{.erlang.cookie}.
diff --git a/src/ejabberd.erl b/src/ejabberd.erl
index 0c7c56a2a..228614b93 100644
--- a/src/ejabberd.erl
+++ b/src/ejabberd.erl
@@ -28,6 +28,7 @@
 -author('alexey@process-one.net').
 
 -export([start/0, stop/0,
+	 get_pid_file/0,
 	 get_so_path/0, get_bin_path/0]).
 
 start() ->
@@ -63,3 +64,14 @@ get_bin_path() ->
 	Path ->
 	    Path
     end.
+
+%% @spec () -> false | string()
+get_pid_file() ->
+    case os:getenv("EJABBERD_PID_PATH") of
+	false ->
+	    false;
+	"" ->
+	    false;
+	Path ->
+	    Path
+    end.
diff --git a/src/ejabberd_app.erl b/src/ejabberd_app.erl
index c68199d19..bea1b0b7a 100644
--- a/src/ejabberd_app.erl
+++ b/src/ejabberd_app.erl
@@ -40,6 +40,7 @@
 
 start(normal, _Args) ->
     ejabberd_loglevel:set(4),
+    write_pid_file(),
     application:start(sasl),
     application:start(exmpp),
     randoms:start(),
@@ -81,6 +82,7 @@ prep_stop(State) ->
 %% All the processes were killed when this function is called
 stop(_State) ->
     ?INFO_MSG("ejabberd ~s is stopped in the node ~p", [?VERSION, node()]),
+    delete_pid_file(),
     ejabberd_debug:stop(),
     ok.
 
@@ -182,3 +184,34 @@ add_windows_nameservers() ->
     IPTs = win32_dns:get_nameservers(),
     ?INFO_MSG("Adding machine's DNS IPs to Erlang system:~n~p", [IPTs]),
     lists:foreach(fun(IPT) -> inet_db:add_ns(IPT) end, IPTs).
+
+
+%%%
+%%% PID file
+%%%
+
+write_pid_file() ->
+    case ejabberd:get_pid_file() of
+	false ->
+	    ok;
+	PidFilename ->
+	    write_pid_file(os:getpid(), PidFilename)
+    end.
+
+write_pid_file(Pid, PidFilename) ->
+    case file:open(PidFilename, [write]) of
+	{ok, Fd} ->
+	    io:format(Fd, "~s~n", [Pid]),
+	    file:close(Fd);
+	{error, Reason} ->
+	    ?ERROR_MSG("Cannot write PID file ~s~nReason: ~p", [PidFilename, Reason]),
+	    throw({cannot_write_pid_file, PidFilename, Reason})
+    end.
+
+delete_pid_file() ->
+    case ejabberd:get_pid_file() of
+	false ->
+	    ok;
+	PidFilename ->
+	    file:delete(PidFilename)
+    end.
diff --git a/src/ejabberdctl.cfg.example b/src/ejabberdctl.cfg.example
index 0c8d0c5a6..1ba413fe2 100644
--- a/src/ejabberdctl.cfg.example
+++ b/src/ejabberdctl.cfg.example
@@ -110,6 +110,18 @@
 #
 #ERLANG_NODE=ejabberd
 
+#.
+#' EJABBERD_PID_PATH: ejabberd PID file
+#
+# Indicate the full path to the ejabberd Process identifier (PID) file.
+# If this variable is defined, ejabberd writes the PID file when starts,
+# and deletes it when stops.
+# Remember to create the directory and grant write permission to ejabberd.
+#
+# Default: don't write PID file
+#
+#EJABBERD_PID_PATH=/var/run/ejabberd/ejabberd.pid
+
 #.
 #'
 # vim: foldmarker=#',#. foldmethod=marker:
diff --git a/src/ejabberdctl.template b/src/ejabberdctl.template
index f6a30bb09..48a56ba5b 100644
--- a/src/ejabberdctl.template
+++ b/src/ejabberdctl.template
@@ -118,6 +118,7 @@ export EJABBERD_LOG_PATH
 export EJABBERD_SO_PATH
 export EJABBERD_BIN_PATH
 export EJABBERD_DOC_PATH
+export EJABBERD_PID_PATH
 export ERL_CRASH_DUMP
 export ERL_INETRC
 export ERL_MAX_PORTS