Debug stub: suspend/resume threads on Linux

src/trusted/service_runtime/posix/nacl_signal.c

 /*
  * Copyright (c) 2012 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include <errno.h>
 #include <signal.h>
 #include <stddef.h>
 #include <string.h>
@@ skipping 339 matching lines @@
   struct sigaction sa;
   unsigned int a;
 
   memset(&sa, 0, sizeof(sa));
   sigemptyset(&sa.sa_mask);
   sa.sa_sigaction = SignalCatch;
   sa.sa_flags = SA_ONSTACK | SA_SIGINFO;
 
   /* Mask all exceptions we catch to prevent re-entry */
   for (a = 0; a < NACL_ARRAY_SIZE(s_Signals); a++) {
-    sigaddset(&sa.sa_mask, s_Signals[a]);
+    if (s_Signals[a] != NACL_THREAD_SUSPEND_SIGNAL) {
+      sigaddset(&sa.sa_mask, s_Signals[a]);
+    }
   }
 
   /* Install all handlers */
   for (a = 0; a < NACL_ARRAY_SIZE(s_Signals); a++) {
     if (sigaction(s_Signals[a], &sa, &s_OldActions[a]) != 0) {
       NaClLog(LOG_FATAL, "Failed to install handler for %d.\n\tERR:%s\n",
                           s_Signals[a], strerror(errno));
     }
   }
 }
@@ skipping 28 matching lines @@
     }
     if ((sa.sa_flags & SA_SIGINFO) != 0
         ? sa.sa_sigaction != NULL
         : (sa.sa_handler != SIG_DFL && sa.sa_handler != SIG_IGN)) {
       NaClLog(LOG_FATAL, "NaClSignalAssertNoHandlers: "
               "A signal handler is registered for signal %d.  "
               "Did Breakpad register this?\n", signum);
     }
   }
 }