bug#7690 - ndb startup with shm, use sigaction to escape SA_RESETHAND

configure.in:
  Check for sigaction used in SHM_Transporter
ndb/src/common/transporter/SHM_Transporter.cpp:
  remove unused variable
ndb/src/common/transporter/TransporterRegistry.cpp:
  1) remove unused variable
  2) Use sigaction instead of signal to install signal handler
     This as signal uses SA_RESETHAND

configure.in

@@ -1924,7 +1924,7 @@ AC_CHECK_FUNCS(alarm bcmp bfill bmove bzero chsize cuserid fchmod fcntl \
   pthread_key_delete pthread_rwlock_rdlock pthread_setprio \
   pthread_setprio_np pthread_setschedparam pthread_sigmask readlink \
   realpath rename rint rwlock_init setupterm \
-  shmget shmat shmdt shmctl \
+  shmget shmat shmdt shmctl sigaction \
   sighold sigset sigthreadmask \
   snprintf socket stpcpy strcasecmp strerror strnlen strpbrk strstr strtol \
   strtoll strtoul strtoull tell tempnam thr_setconcurrency vidattr)
@@ -3097,7 +3097,8 @@ ndb_transporter_opt_objs=""
 if test "$ac_cv_func_shmget" = "yes" &&
    test "$ac_cv_func_shmat" = "yes" &&
    test "$ac_cv_func_shmdt" = "yes" &&
-   test "$ac_cv_func_shmctl" = "yes"
+   test "$ac_cv_func_shmctl" = "yes" &&
+   test "$ac_cv_func_sigaction" = "yes"
 then
    AC_DEFINE([NDB_SHM_TRANSPORTER], [1],
              [Including Ndb Cluster DB shared memory transporter])

ndb/src/common/transporter/SHM_Transporter.cpp

@@ -26,8 +26,6 @@
 #include <InputStream.hpp>
 #include <OutputStream.hpp>
 
-extern int g_shm_pid;
-
 SHM_Transporter::SHM_Transporter(TransporterRegistry &t_reg,
 				 const char *lHostName,
 				 const char *rHostName, 

ndb/src/common/transporter/TransporterRegistry.cpp

@@ -50,8 +50,6 @@
 #include <EventLogger.hpp>
 extern EventLogger g_eventLogger;
 
-int g_shm_pid = 0;
-
 SocketServer::Session * TransporterService::newSession(NDB_SOCKET_TYPE sockfd)
 {
   DBUG_ENTER("SocketServer::Session * TransporterService::newSession");
@@ -1322,7 +1320,22 @@ TransporterRegistry::startReceiving()
 
 #ifdef NDB_SHM_TRANSPORTER
   m_shm_own_pid = getpid();
-  signal(SIGUSR1, shm_sig_handler);
+  struct sigaction sa;
+  sa.sa_handler = shm_sig_handler;
+  sigemptyset(&sa.sa_mask);
+  sa.sa_flags = 0;
+  int ret;
+  while((ret = sigaction(SIGUSR1, &sa, 0)) == -1 && errno == EINTR);
+  if(ret != 0)
+  {
+    g_eventLogger.error("Failed to install signal handler for SHM transporter"
+			" errno: %d (%s)", errno, 
+#ifdef HAVE_STRERROR
+			strerror(errno));
+#else
+                        "");
+#endif
+  }
 #endif
 }