patch for distinguishing PG instances in event log v2

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
new file mode 100644
index 5d37065..9d73640
*** a/doc/src/sgml/config.sgml
--- b/doc/src/sgml/config.sgml
*************** local0.*    /var/log/postgresql
*** 2949,2954 ****
--- 2949,2962 ----
           to the  <application>syslog</application> daemon's configuration file
           to make it work.
          </para>
+         <para>
+          On Windows, when you use the <systemitem>eventlog</systemitem>
+          option for <varname>log_destination</>, you should
+          register an event sourceand its library with the operating
+          system so that the Windows Event Viewer can display event
+          log messages cleanly.
+          See <xref linkend="event-log-registration"> for details.
+         </para>
         </note>
        </listitem>
       </varlistentry>
*************** local0.*    /var/log/postgresql
*** 3189,3194 ****
--- 3197,3220 ----
           <productname>PostgreSQL</productname> messages in
           <application>syslog</application> logs. The default is
           <literal>postgres</literal>.
+          This parameter can only be set in the <filename>postgresql.conf</>
+          file or on the server command line.
+         </para>
+        </listitem>
+       </varlistentry>
+ 
+      <varlistentry id="guc-event-source" xreflabel="event_source">
+       <term><varname>event_source</varname> (<type>string</type>)</term>
+       <indexterm>
+        <primary><varname>event_source</> configuration parameter</primary>
+       </indexterm>
+        <listitem>
+         <para>
+          When logging to <application>event log</> is enabled, this parameter
+          determines the program name used to identify
+          <productname>PostgreSQL</productname> messages in
+          <application>event log</application>. The default is
+          <literal>PostgreSQL</literal>.
           This parameter can only be set in the <filename>postgresql.conf</>
           file or on the server command line.
          </para>
diff --git a/doc/src/sgml/installation.sgml b/doc/src/sgml/installation.sgml
new file mode 100644
index 96387bd..262b91a
*** a/doc/src/sgml/installation.sgml
--- b/doc/src/sgml/installation.sgml
*************** PostgreSQL, contrib and HTML documentati
*** 1551,1569 ****
    </procedure>
  
    <formalpara>
-    <title>Registering <application>eventlog</> on <systemitem
-    class="osname">Windows</>:</title>
-    <para>
-     To register a <systemitem class="osname">Windows</> <application>eventlog</>
-     library with the operating system, issue this command after installation:
- <screen>
- <userinput>regsvr32 <replaceable>pgsql_library_directory</>/pgevent.dll</>
- </screen>
-     This creates registry entries used by the event viewer.
-    </para>
-   </formalpara>
- 
-   <formalpara>
     <title>Uninstallation:</title>
     <para>
      To undo the installation use the command <command>gmake
--- 1551,1556 ----
diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
new file mode 100644
index d18ba79..9a8a22d
*** a/doc/src/sgml/runtime.sgml
--- b/doc/src/sgml/runtime.sgml
*************** ssh -L 63333:db.foo.com:5432 joe@shell.f
*** 2294,2297 ****
--- 2294,2347 ----
  
   </sect1>
  
+  <sect1 id="event-log-registration">
+   <title>Registering <application>Event Log</> on <systemitem
+   class="osname">Windows</></title>
+ 
+   <indexterm zone="event-log-registration">
+    <primary>event log</primary>
+    <secondary>event log</secondary>
+   </indexterm>
+ 
+   <para>
+    To register a <systemitem class="osname">Windows</> <application>event log</>
+    library with the operating system, issue this command:
+ <screen>
+ <userinput>regsvr32 <replaceable>pgsql_library_directory</>/pgevent.dll</>
+ </screen>
+    This creates registry entries used by the event viewer, under the default event
+    source named "PostgreSQL".
+    </para>
+ 
+    <para>
+    You can specify the event source name with /i option. In this case, -n option
+    is necessary, too:
+ <screen>
+ <userinput>regsvr32 /n /i:<replaceable>event_source_name</>
+  <replaceable>pgsql_library_directory</>/pgevent.dll</>
+ </screen>
+    You also need to set <xref linkend="guc-event-source"> in
+    <filename>postgresql.conf</filename>. Note that the event source specification
+    only takes effect for the database server. Other applications like
+    <command>pg_ctl</command> always use "PostgreSQL" event source.
+    </para>
+ 
+    <para>
+    To unregister the <application>event log</> library from
+    the operating system, issue this command:
+ <screen>
+ <userinput>regsvr32 /u [/i:<replaceable>event_source_name</>]
+  <replaceable>pgsql_library_directory</>/pgevent.dll</>
+ </screen>
+    </para>
+ 
+   <note>
+    <para>
+     To enable event logging in the database server, modify
+     <xref linkend="guc-log-destination"> to include
+     <systemitem>eventlog</systemitem> in <filename>postgresql.conf</filename>.
+    </para>
+   </note>
+  </sect1>
+ 
  </chapter>
diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
new file mode 100644
index 337b875..47ee4df
*** a/src/backend/utils/error/elog.c
--- b/src/backend/utils/error/elog.c
*************** static void write_syslog(int level, cons
*** 122,127 ****
--- 122,128 ----
  static void write_console(const char *line, int len);
  
  #ifdef WIN32
+ extern char *event_source; /* guc */
  static void write_eventlog(int level, const char *line, int len);
  #endif
  
*************** write_eventlog(int level, const char *li
*** 1645,1651 ****
  
  	if (evtHandle == INVALID_HANDLE_VALUE)
  	{
! 		evtHandle = RegisterEventSource(NULL, "PostgreSQL");
  		if (evtHandle == NULL)
  		{
  			evtHandle = INVALID_HANDLE_VALUE;
--- 1646,1652 ----
  
  	if (evtHandle == INVALID_HANDLE_VALUE)
  	{
! 		evtHandle = RegisterEventSource(NULL, event_source ? event_source : "PostgreSQL");
  		if (evtHandle == NULL)
  		{
  			evtHandle = INVALID_HANDLE_VALUE;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
new file mode 100644
index 92391ed..a6420b2
*** a/src/backend/utils/misc/guc.c
--- b/src/backend/utils/misc/guc.c
*************** bool		log_executor_stats = false;
*** 411,416 ****
--- 411,417 ----
  bool		log_statement_stats = false;		/* this is sort of all three
  												 * above together */
  bool		log_btree_build_stats = false;
+ char	   *event_source;
  
  bool		check_function_bodies = true;
  bool		default_with_oids = false;
*************** int			tcp_keepalives_count;
*** 449,454 ****
--- 450,458 ----
  static char *log_destination_string;
  
  static char *syslog_ident_str;
+ #ifdef WIN32
+ static char *event_source_str;
+ #endif
  static bool phony_autocommit;
  static bool session_auth_is_superuser;
  static double phony_random_seed;
*************** static struct config_string ConfigureNam
*** 2822,2827 ****
--- 2826,2844 ----
  		NULL, assign_syslog_ident, NULL
  	},
  
+ #ifdef WIN32
+ 	{
+ 		{"event_source", PGC_POSTMASTER, LOGGING_WHERE,
+ 			gettext_noop("Sets the application name used to identify"
+ 						 "PostgreSQL messages in the event log."),
+ 			NULL
+ 		},
+ 		&event_source,
+ 		"PostgreSQL",
+ 		NULL, NULL, NULL
+ 	},
+ #endif
+ 
  	{
  		{"TimeZone", PGC_USERSET, CLIENT_CONN_LOCALE,
  			gettext_noop("Sets the time zone for displaying and interpreting time stamps."),
*************** assign_syslog_ident(const char *newval, 
*** 8213,8219 ****
  #endif
  	/* Without syslog support, it will always be set to "none", so ignore */
  }
- 
  
  static void
  assign_session_replication_role(int newval, void *extra)
--- 8230,8235 ----
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
new file mode 100644
index 655dad4..a6f4c3d
*** a/src/backend/utils/misc/postgresql.conf.sample
--- b/src/backend/utils/misc/postgresql.conf.sample
***************
*** 300,305 ****
--- 300,308 ----
  #syslog_facility = 'LOCAL0'
  #syslog_ident = 'postgres'
  
+ # This is relevant only when logging to eventlog:
+ #event_source = 'PostgreSQL'
+ 
  #silent_mode = off			# Run server silently.
  					# DO NOT USE without syslog or
  					# logging_collector
diff --git a/src/bin/pgevent/pgevent.c b/src/bin/pgevent/pgevent.c
new file mode 100644
index 1fcde86..cab75c3
*** a/src/bin/pgevent/pgevent.c
--- b/src/bin/pgevent/pgevent.c
***************
*** 15,31 ****
  #include <windows.h>
  #include <olectl.h>
  #include <string.h>
  
  /* Global variables */
  HANDLE		g_module = NULL;	/* hModule of DLL */
  
  /* Prototypes */
! STDAPI
! DllRegisterServer(void);
  STDAPI		DllUnregisterServer(void);
  BOOL WINAPI DllMain(HANDLE hModule, DWORD ul_reason_for_call, LPVOID lpReserved);
  
  /*
   * DllRegisterServer --- Instructs DLL to create its registry entries
   */
  
--- 15,67 ----
  #include <windows.h>
  #include <olectl.h>
  #include <string.h>
+ #include <stdio.h>
+ #include <stdlib.h>
  
  /* Global variables */
  HANDLE		g_module = NULL;	/* hModule of DLL */
+ /*
+  * The event source is stored as a registry key.
+  * The maximum length of a registry key is 255 characters.
+  * http://msdn.microsoft.com/en-us/library/ms724872(v=vs.85).aspx
+  */
+ char		event_source[256] = "PostgreSQL";
  
  /* Prototypes */
! HRESULT DllInstall(BOOL bInstall, __in_opt LPCWSTR pszCmdLine);
! STDAPI		DllRegisterServer(void);
  STDAPI		DllUnregisterServer(void);
  BOOL WINAPI DllMain(HANDLE hModule, DWORD ul_reason_for_call, LPVOID lpReserved);
  
  /*
+  * DllInstall --- Passes the command line argument to DLL
+  */
+ 
+ HRESULT
+ DllInstall(BOOL bInstall,
+ 		__in_opt LPCWSTR pszCmdLine)
+ {
+ 	size_t ret;
+ 
+ 	if (pszCmdLine && *pszCmdLine != '\0')
+ 		wcstombs_s(&ret, event_source, sizeof(event_source), 
+ 			pszCmdLine, sizeof(event_source));
+ 
+ 	/*
+ 	 * This is an ugry part due to the strange behavior of "regsvr32 /i".
+ 	 * When installing, regsvr32 calls DllRegisterServer before DllInstall.
+ 	 * When uninstalling (i.e. "regsvr32 /u /i"), on the other hand, 
+ 	 * regsvr32 calls DllInstall and then DllUnregisterServer as expected.
+ 	 * This strange behavior forces us to specify -n (i.e. "regsvr32 /n /i").
+ 	 * Without -n, DllRegisterServer called before DllInstall would
+ 	 * mistakenly overwrite the default "PostgreSQL" event source registration.
+ 	 */
+ 	if (bInstall)
+ 		DllRegisterServer();
+ 	return S_OK;
+ }
+ 
+ /*
   * DllRegisterServer --- Instructs DLL to create its registry entries
   */
  
*************** DllRegisterServer(void)
*** 35,40 ****
--- 71,77 ----
  	HKEY		key;
  	DWORD		data;
  	char		buffer[_MAX_PATH];
+ 	char		key_name[400];
  
  	/* Set the name of DLL full path name. */
  	if (!GetModuleFileName((HMODULE) g_module, buffer, sizeof(buffer)))
*************** DllRegisterServer(void)
*** 47,53 ****
  	 * Add PostgreSQL source name as a subkey under the Application key in the
  	 * EventLog registry key.
  	 */
! 	if (RegCreateKey(HKEY_LOCAL_MACHINE, "SYSTEM\\CurrentControlSet\\Services\\EventLog\\Application\\PostgreSQL", &key))
  	{
  		MessageBox(NULL, "Could not create the registry key.", "PostgreSQL error", MB_OK | MB_ICONSTOP);
  		return SELFREG_E_TYPELIB;
--- 84,93 ----
  	 * Add PostgreSQL source name as a subkey under the Application key in the
  	 * EventLog registry key.
  	 */
! 	snprintf(key_name, sizeof(key_name), 
! 		"SYSTEM\\CurrentControlSet\\Services\\EventLog\\Application\\%s",
! 		event_source);
! 	if (RegCreateKey(HKEY_LOCAL_MACHINE, key_name, &key))
  	{
  		MessageBox(NULL, "Could not create the registry key.", "PostgreSQL error", MB_OK | MB_ICONSTOP);
  		return SELFREG_E_TYPELIB;
*************** DllRegisterServer(void)
*** 90,101 ****
  STDAPI
  DllUnregisterServer(void)
  {
  	/*
  	 * Remove PostgreSQL source name as a subkey under the Application key in
  	 * the EventLog registry key.
  	 */
  
! 	if (RegDeleteKey(HKEY_LOCAL_MACHINE, "SYSTEM\\CurrentControlSet\\Services\\EventLog\\Application\\PostgreSQL"))
  	{
  		MessageBox(NULL, "Could not delete the registry key.", "PostgreSQL error", MB_OK | MB_ICONSTOP);
  		return SELFREG_E_TYPELIB;
--- 130,146 ----
  STDAPI
  DllUnregisterServer(void)
  {
+ 	char		key_name[400];
+ 
  	/*
  	 * Remove PostgreSQL source name as a subkey under the Application key in
  	 * the EventLog registry key.
  	 */
  
! 	snprintf(key_name, sizeof(key_name), 
! 		"SYSTEM\\CurrentControlSet\\Services\\EventLog\\Application\\%s",
! 		event_source);
! 	if (RegDeleteKey(HKEY_LOCAL_MACHINE, key_name))
  	{
  		MessageBox(NULL, "Could not delete the registry key.", "PostgreSQL error", MB_OK | MB_ICONSTOP);
  		return SELFREG_E_TYPELIB;
diff --git a/src/bin/pgevent/pgevent.def b/src/bin/pgevent/pgevent.def
new file mode 100644
index 21bab7a..6b4d44a
*** a/src/bin/pgevent/pgevent.def
--- b/src/bin/pgevent/pgevent.def
***************
*** 2,4 ****
--- 2,5 ----
  EXPORTS
  	DllUnregisterServer ;
  	DllRegisterServer ;
+ 	DllInstall ;