Re: [RFA/JVMTI] SuspendThread and ResumeThread

[Keith Seitz <keiths at redhat dot com>]

Keith Seitz wrote:

> As requested here are the JVMTI functions SuspendThread and 
> ResumeThread. They're very basic. They don't check for some error 
> conditions (like checking whether the thread to be suspended is already 
> suspended). I have them working in my sandbox breakpoint-enabled gij.

Actually, I'd like to submit this alternative version for the two JVMTI 
functions, which now do at least some validity checking.

I've attached the patch in its entirety for completeness.

Keith
Index: boehm.cc
===================================================================
--- boehm.cc	(revision 115627)
+++ boehm.cc	(working copy)
@@ -678,19 +678,20 @@
 #endif
 }
 
-#if defined(GC_PTHREADS) && !defined(GC_SOLARIS_THREADS) \
-  && !defined(GC_WIN32_THREADS) && !defined(GC_DARWIN_THREADS)
-
 void
 _Jv_SuspendThread (_Jv_Thread_t *thread)
 {
+#if defined(GC_PTHREADS) && !defined(GC_SOLARIS_THREADS) \
+     && !defined(GC_WIN32_THREADS) && !defined(GC_DARWIN_THREADS)
   GC_suspend_thread (_Jv_GetPlatformThreadID (thread));
+#endif
 }
 
 void
 _Jv_ResumeThread (_Jv_Thread_t *thread)
 {
+#if defined(GC_PTHREADS) && !defined(GC_SOLARIS_THREADS) \
+     && !defined(GC_WIN32_THREADS) && !defined(GC_DARWIN_THREADS)
   GC_resume_thread (_Jv_GetPlatformThreadID (thread));
+#endif
 }
-
-#endif
Index: posix-threads.cc
===================================================================
--- posix-threads.cc	(revision 115627)
+++ posix-threads.cc	(working copy)
@@ -505,22 +505,6 @@
   pthread_mutex_unlock (&daemon_mutex);
 }
 
-void
-_Jv_ThreadDebugSuspend (_Jv_Thread_t *data)
-{
-}
-
-void
-_Jv_ThreadDebugResume (_Jv_Thread_t *data)
-{
-}
-
-jint
-_Jv_ThreadDebugSuspendCount (_Jv_Thread_t *data)
-{
-  return -1;
-}
-
 #if defined(SLOW_PTHREAD_SELF)
 
 #include "sysdep/locks.h"
Index: jvmti.cc
===================================================================
--- jvmti.cc	(revision 115631)
+++ jvmti.cc	(working copy)
@@ -11,8 +11,56 @@
 #include <config.h>
 
 #include <jvm.h>
+#include <java-threads.h>
+#include <java-gc.h>
 #include <jvmti.h>
 
+#include <java/lang/Thread.h>
+
+// Some commonly-used checks
+
+#define THREAD_DEFAULT_TO_CURRENT(jthread)				\
+  if (jthread == NULL) jthread = java::lang::Thread::currentThread ();
+
+#define THREAD_CHECK_VALID(jthread)					\
+  if (!java::lang::Thread::class$.isAssignableFrom (&(jthread->class$))) \
+    return JVMTI_ERROR_INVALID_THREAD;
+
+#define THREAD_CHECK_IS_ALIVE(thread)				\
+  if (!thread->isAlive ()) return JVMTI_ERROR_THREAD_NOT_ALIVE;
+
+static jvmtiError
+_Jv_JVMTI_SuspendThread (MAYBE_UNUSED jvmtiEnv *env, jthread thread)
+{
+  using namespace java::lang;
+
+  THREAD_DEFAULT_TO_CURRENT (thread);
+  THREAD_CHECK_VALID (thread);
+
+  Thread *t = reinterpret_cast<Thread *> (thread);
+  THREAD_CHECK_IS_ALIVE (t);
+
+  _Jv_Thread_t *data = _Jv_ThreadGetData (t);
+  _Jv_SuspendThread (data);
+  return JVMTI_ERROR_NONE;
+}
+
+static jvmtiError
+_Jv_JVMTI_ResumeThread (MAYBE_UNUSED jvmtiEnv *env, jthread thread)
+{
+  using namespace java::lang;
+
+  THREAD_DEFAULT_TO_CURRENT (thread);
+  THREAD_CHECK_VALID (thread);
+
+  Thread *t = reinterpret_cast<Thread *> (thread);
+  THREAD_CHECK_IS_ALIVE (t);
+
+  _Jv_Thread_t *data = _Jv_ThreadGetData (t);
+  _Jv_ResumeThread (data);
+  return JVMTI_ERROR_NONE;
+}
+
 #define RESERVED NULL
 #define UNIMPLEMENTED NULL
 
@@ -30,8 +78,8 @@
   UNIMPLEMENTED,		// SetEventNotification
   RESERVED,			// reserved3
   UNIMPLEMENTED,		// GetAllThreads
-  UNIMPLEMENTED, 		// SuspendThread
-  UNIMPLEMENTED,		// ResumeThread
+  _Jv_JVMTI_SuspendThread,	// SuspendThread
+  _Jv_JVMTI_ResumeThread,	// ResumeThread
   UNIMPLEMENTED,		// StopThread
   UNIMPLEMENTED,		// InterruptThread
   UNIMPLEMENTED,		// GetThreadInfo