repmgrd: enable package to supply default PID file path

Also add documentation for packagers about paths which can be patched
as default package values.

doc/appendix-packages.sgml

@@ -364,4 +364,48 @@
    </sect2>
 
   </sect1>
+
+
+  <sect1 id="packages-packager-info" xreflabel="Information for packagers">
+    <title>Information for packagers</title>
+    <indexterm>
+      <primary>packages</primary>
+      <secondary>information for packagers</secondary>
+    </indexterm>
+    <para>
+      We recommend patching the following  parameters when
+      building the package as built-in default values for user convenience.
+      These values can nevertheless be overridden by the user, if desired.
+    </para>
+    <itemizedlist>
+      <listitem>
+        <para>
+          Configuration file location: the default configuration file location
+          can be hard-coded by patching <varname>package_conf_file</varname>
+          in <filename>configfile.c</filename>:
+          <programlisting>
+		/* packagers: if feasible, patch configuration file path into "package_conf_file" */
+		char		package_conf_file[MAXPGPATH] = "";</programlisting>
+        </para>
+        <para>
+          See also: <xref linkend="configuration-file">
+        </para>
+      </listitem>
+
+      <listitem>
+        <para>
+          PID file location: the default <application>repmgrd</application> PID file
+          location can be hard-coded by patching <varname>package_pid_file</varname>
+          in <filename>repmgrd.c</filename>:
+          <programlisting>
+		/* packagers: if feasible, patch PID file path into "package_pid_file" */
+		char		package_pid_file[MAXPGPATH] = "";</programlisting>
+        </para>
+        <para>
+          See also: <xref linkend="repmgrd-pid-file">
+        </para>
+      </listitem>
+
+    </itemizedlist>
+  </sect1>
 </appendix>

doc/repmgrd-configuration.sgml

@@ -170,11 +170,15 @@
       running <application>repmgrd</application> daemon.
     </para>
 
-    <sect2 id="repmgrd-pid-file">
+    <sect2 id="repmgrd-pid-file" xreflabel="repmgrd's PID file">
       <indexterm>
         <primary>repmgrd</primary>
         <secondary>PID file</secondary>
       </indexterm>
+      <indexterm>
+        <primary>PID file</primary>
+        <secondary>repmgrd</secondary>
+      </indexterm>
       <title>repmgrd's PID file</title>
       <para>
         <application>repmgrd</application> will generate a PID file by default.
@@ -197,16 +201,21 @@
         <option>--pid-file</option> may be deprecated in future releases.
       </para>
       <para>
-        If no PID file is specified, <application>repmgrd</application> will create one
+        If a PID file location was specified by the package maintainer, <application>repmgrd</application>
-        in the operating system's temporary directory (determined by the environment variable
+        will use that. This only applies if &repmgr; was installed from a package and the package
-        <varname>TMPDIR</varname>, or if that is not set, will use <filename>/tmp</filename>.
+        maintainer has specified the PID file location.
+      </para>
+      <para>
+        If none of the above apply, <application>repmgrd</application> will create a PID file
+        in the operating system's temporary directory (das etermined by the environment variable
+        <varname>TMPDIR</varname>, or if that is not set, will use <filename>/tmp</filename>).
       </para>
       <para>
         To prevent a PID file being generated at all, provide the command line option
         <option>--no-pid-file</option>.
       </para>
       <para>
-        To see which PID file would use, execute <application>repmgrd</application>
+        To see which PID file <application>repmgrd</application> would use, execute <application>repmgrd</application>
         with the option <option>--show-pid-file</option>. <application>repmgrd</application>
         will not start if this option is provided. Note that the value shown is the
         file  <application>repmgrd</application> would use next time it starts, and is

repmgrd.c

@@ -275,12 +275,22 @@ main(int argc, char **argv)
 		/* no pid file provided - determine location */
 		if (pid_file[0] == '\0')
 		{
-			const char *tmpdir = getenv("TMPDIR");
+			/* packagers: if feasible, patch PID file path into "package_pid_file" */
+			char		package_pid_file[MAXPGPATH] = "";
 
-			if (!tmpdir)
+			if (package_pid_file[0] != '\0')
-				tmpdir = "/tmp";
+			{
+				maxpath_snprintf(pid_file, "%s", package_pid_file);
+			}
+			else
+			{
+				const char *tmpdir = getenv("TMPDIR");
 
-			maxpath_snprintf(pid_file, "%s/repmgrd.pid", tmpdir);
+				if (!tmpdir)
+					tmpdir = "/tmp";
+
+				maxpath_snprintf(pid_file, "%s/repmgrd.pid", tmpdir);
+			}
 		}
 	}
 	else