From 091b0e828cf0fd5bbd1f9ae58ab96fc983e55d77 Mon Sep 17 00:00:00 2001
From: Michael P
Date: Thu, 30 Jun 2011 08:41:18 +0900
Subject: Support for GTM-Proxy reconnection

This commit adds support for GTM-Proxy reconnection.
After promoting a GTM-Standby instance, it is possible
to reorientate Proxy worker threads to the newly-promoted
GTM instance.

Implemented in gtm_ctl, GTM reconnection uses USR1/USR2 to signal
GTM-Proxy main thread or worker threads.
If a worker thread receives a USR1 signal, it transmits it to the main thread.
After main thread has received USR1 signal, it signals worker threads with USR2.
Signal handling is managed by longjump.

A new keyword "reconnect" has been added in gtm_ctl.
Ex:
gtm_ctl reconnect -S gtm_proxy -D $PROXY_DATA -o '-s $STANDBY_HOST -t $STANDBY_PORT'
It is expected that new connection parameters to GTM are specified in string -o.

Implementation by Koichi Suzuki
---
 src/include/gtm/gtm_proxy.h | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

(limited to 'src/include')

diff --git a/src/include/gtm/gtm_proxy.h b/src/include/gtm/gtm_proxy.h
index ead825320b..d7db891c6a 100644
--- a/src/include/gtm/gtm_proxy.h
+++ b/src/include/gtm/gtm_proxy.h
@@ -120,6 +120,13 @@ typedef struct GTMProxy_ThreadInfo
 	gtm_List 					*thr_pending_commands[MSG_TYPE_COUNT];
 
 	GTM_Conn				*thr_gtm_conn;
+
+	/* Reconnect Info */
+	int						can_accept_SIGUSR2;
+	int						reconnect_issued;
+	int						can_longjmp;
+	sigjmp_buf				longjmp_env;
+
 } GTMProxy_ThreadInfo;
 
 typedef struct GTMProxy_Threads
@@ -138,7 +145,7 @@ int GTMProxy_ThreadRemove(GTMProxy_ThreadInfo *thrinfo);
 int GTMProxy_ThreadJoin(GTMProxy_ThreadInfo *thrinfo);
 void GTMProxy_ThreadExit(void);
 
-extern GTMProxy_ThreadInfo *GTMProxy_ThreadCreate(void *(* startroutine)(void *));
+extern GTMProxy_ThreadInfo *GTMProxy_ThreadCreate(void *(* startroutine)(void *), int idx);
 extern GTMProxy_ThreadInfo * GTMProxy_GetThreadInfo(GTM_ThreadID thrid);
 extern GTMProxy_ThreadInfo *GTMProxy_ThreadAddConnection(GTMProxy_ConnectionInfo *conninfo);
 extern int GTMProxy_ThreadRemoveConnection(GTMProxy_ThreadInfo *thrinfo,
@@ -236,4 +243,23 @@ extern GTM_ThreadID						TopMostThreadID;
 		    CritSectionCount--; \
 	} while(0)
 
+/* Signal Handler controller */
+#define SIGUSR2DETECTED() (GetMyThreadInfo->reconnect_issued == TRUE)
+#define RECONNECT_LONGJMP() do{longjmp(GetMyThreadInfo->longjmp_env, 1);}while(0)
+#if 1
+#define Disable_Longjmp() do{GetMyThreadInfo->can_longjmp = FALSE;}while(0)
+#define Enable_Longjmp() \
+	do{						 \
+		if (SIGUSR2DETECTED()) { \
+			RECONNECT_LONGJMP(); \
+		} \
+		else { \
+			GetMyThreadInfo->can_longjmp = TRUE;	\
+		} \
+	} while(0)
+#else
+#define Disable_Longjmp() 
+#define Enable_Longjmp()
+#endif
+	
 #endif
-- 
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