From e8ea40668b1f2dcc0d61760ad3bccd98e0d77b8c Mon Sep 17 00:00:00 2001
From: Eric Milkie <milkie@10gen.com>
Date: Thu, 18 Apr 2013 11:33:22 -0400
Subject: SERVER-4739 use a thread for logRotate signal instead of a signal
 handler

---
 src/mongo/db/cmdline.cpp |  5 -----
 src/mongo/db/db.cpp      | 25 +++++++++++++++++++------
 src/mongo/s/server.cpp   | 34 +++++++++++++++++++++++++++++++++-
 3 files changed, 52 insertions(+), 12 deletions(-)

diff --git a/src/mongo/db/cmdline.cpp b/src/mongo/db/cmdline.cpp
index c070d6165b2..b40400d17e6 100644
--- a/src/mongo/db/cmdline.cpp
+++ b/src/mongo/db/cmdline.cpp
@@ -520,13 +520,8 @@ namespace mongo {
 
     void ignoreSignal( int sig ) {}
 
-    static void rotateLogsOrDie(int sig) {
-        fassert(16176, rotateLogs());
-    }
-
     void setupCoreSignals() {
 #if !defined(_WIN32)
-        verify( signal(SIGUSR1 , rotateLogsOrDie ) != SIG_ERR );
         verify( signal(SIGHUP , ignoreSignal ) != SIG_ERR );
 #endif
     }
diff --git a/src/mongo/db/db.cpp b/src/mongo/db/db.cpp
index e870e3793ed..fb3b9e28e53 100644
--- a/src/mongo/db/db.cpp
+++ b/src/mongo/db/db.cpp
@@ -1205,12 +1205,24 @@ namespace mongo {
     // The above signals will be processed by this thread only, in order to
     // ensure the db and log mutexes aren't held.
     void interruptThread() {
-        int actualSignal;
-        sigwait( &asyncSignals, &actualSignal );
-        log() << "got signal " << actualSignal << " (" << strsignal( actualSignal )
-              << "), will terminate after current cmd ends" << endl;
-        Client::initThread( "interruptThread" );
-        exitCleanly( EXIT_CLEAN );
+        while (true) {
+            int actualSignal = 0;
+            int status = sigwait( &asyncSignals, &actualSignal );
+            fassert(16781, status == 0);
+            switch (actualSignal) {
+            case SIGUSR1:
+                // log rotate signal
+                fassert(16782, rotateLogs());
+                break;
+            default:
+                // interrupt/terminate signal
+                Client::initThread( "signalProcessingThread" );
+                log() << "got signal " << actualSignal << " (" << strsignal( actualSignal )
+                      << "), will terminate after current cmd ends" << endl;
+                exitCleanly( EXIT_CLEAN );
+                break;
+            }
+        }
     }
 
     // this will be called in certain c++ error cases, for example if there are two active
@@ -1256,6 +1268,7 @@ namespace mongo {
         sigemptyset( &asyncSignals );
         sigaddset( &asyncSignals, SIGINT );
         sigaddset( &asyncSignals, SIGTERM );
+        sigaddset( &asyncSignals, SIGUSR1 );
         verify( pthread_sigmask( SIG_SETMASK, &asyncSignals, 0 ) == 0 );
         boost::thread it( interruptThread );
     }
diff --git a/src/mongo/s/server.cpp b/src/mongo/s/server.cpp
index 1fe98e05e97..b7c368e13d6 100644
--- a/src/mongo/s/server.cpp
+++ b/src/mongo/s/server.cpp
@@ -45,6 +45,7 @@
 #include "../util/processinfo.h"
 #include "mongo/db/lasterror.h"
 #include "mongo/util/stacktrace.h"
+#include "mongo/util/log.h"
 
 #if defined(_WIN32)
 # include "../util/ntservice.h"
@@ -151,6 +152,33 @@ namespace mongo {
         ::_exit(EXIT_ABRUPT);
     }
 
+#ifndef _WIN32
+    sigset_t asyncSignals;
+
+    void signalProcessingThread() {
+        while (true) {
+            int actualSignal = 0;
+            int status = sigwait( &asyncSignals, &actualSignal );
+            fassert(16779, status == 0);
+            switch (actualSignal) {
+            case SIGUSR1:
+                // log rotate signal
+                fassert(16780, rotateLogs());
+                break;
+            default:
+                // no one else should be here
+                fassertFailed(16778);
+                break;
+            }
+        }
+    }
+
+    void startSignalProcessingThread() {
+        verify( pthread_sigmask( SIG_SETMASK, &asyncSignals, 0 ) == 0 );
+        boost::thread it( signalProcessingThread );
+    }
+#endif
+
     void setupSignals( bool inFork ) {
         signal(SIGTERM, sighandler);
         signal(SIGINT, sighandler);
@@ -167,7 +195,11 @@ namespace mongo {
 #if defined(SIGPIPE)
         signal( SIGPIPE , SIG_IGN );
 #endif
-
+#ifndef _WIN32
+        sigemptyset( &asyncSignals );
+        sigaddset( &asyncSignals, SIGUSR1 );
+        startSignalProcessingThread();
+#endif
         set_new_handler( my_new_handler );
     }
 
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