--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/os/windows/vm/attachListener_windows.cpp Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,400 @@
+/*
+ * Copyright 2005-2006 Sun Microsystems, Inc. All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+# include "incls/_precompiled.incl"
+# include "incls/_attachListener_windows.cpp.incl"
+
+#include <windows.h>
+#include <signal.h> // SIGBREAK
+
+// The AttachListener thread services a queue of operations. It blocks in the dequeue
+// function until an operation is enqueued. A client enqueues an operation by creating
+// a thread in this process using the Win32 CreateRemoteThread function. That thread
+// executes a small stub generated by the client. The stub invokes the
+// JVM_EnqueueOperation function which checks the operation parameters and enqueues
+// the operation to the queue serviced by the attach listener. The thread created by
+// the client is a native thread and is restricted to a single page of stack. To keep
+// it simple operations are pre-allocated at initialization time. An enqueue thus
+// takes a preallocated operation, populates the operation parameters, adds it to
+// queue and wakes up the attach listener.
+//
+// When an operation has completed the attach listener is required to send the
+// operation result and any result data to the client. In this implementation the
+// client is a pipe server. In the enqueue operation it provides the name of pipe
+// to this process. When the operation is completed this process opens the pipe and
+// sends the result and output back to the client. Note that writing to the pipe
+// (and flushing the output) is a blocking operation. This means that a non-responsive
+// client could potentially hang the attach listener thread indefinitely. In that
+// case no new operations would be executed but the VM would continue as normal.
+// As only suitably privileged processes can open this process we concluded that
+// this wasn't worth worrying about.
+
+
+// forward reference
+class Win32AttachOperation;
+
+
+class Win32AttachListener: AllStatic {
+ private:
+ enum {
+ preallocate_count = 4 // number of preallocated operations
+ };
+
+ // protects the preallocated list and the operation list
+ static HANDLE _mutex;
+
+ // head of preallocated operations list
+ static Win32AttachOperation* _avail;
+
+ // head and tail of enqueue operations list
+ static Win32AttachOperation* _head;
+ static Win32AttachOperation* _tail;
+
+
+ static Win32AttachOperation* head() { return _head; }
+ static void set_head(Win32AttachOperation* head) { _head = head; }
+
+ static Win32AttachOperation* tail() { return _tail; }
+ static void set_tail(Win32AttachOperation* tail) { _tail = tail; }
+
+
+ // used to wakeup the listener
+ static HANDLE _wakeup;
+ static HANDLE wakeup() { return _wakeup; }
+
+ public:
+ enum {
+ ATTACH_ERROR_DISABLED = 100, // error codes
+ ATTACH_ERROR_RESOURCE = 101,
+ ATTACH_ERROR_ILLEGALARG = 102,
+ ATTACH_ERROR_INTERNAL = 103
+ };
+
+ static int init();
+ static HANDLE mutex() { return _mutex; }
+
+ static Win32AttachOperation* available() { return _avail; }
+ static void set_available(Win32AttachOperation* avail) { _avail = avail; }
+
+ // enqueue an operation to the end of the list
+ static int enqueue(char* cmd, char* arg1, char* arg2, char* arg3, char* pipename);
+
+ // dequeue an operation from from head of the list
+ static Win32AttachOperation* dequeue();
+};
+
+// statics
+HANDLE Win32AttachListener::_mutex;
+HANDLE Win32AttachListener::_wakeup;
+Win32AttachOperation* Win32AttachListener::_avail;
+Win32AttachOperation* Win32AttachListener::_head;
+Win32AttachOperation* Win32AttachListener::_tail;
+
+
+// Win32AttachOperation is an AttachOperation that additionally encapsulates the name
+// of a pipe which is used to send the operation reply/output to the client.
+// Win32AttachOperation can also be linked in a list.
+
+class Win32AttachOperation: public AttachOperation {
+ private:
+ friend class Win32AttachListener;
+
+ enum {
+ pipe_name_max = 256 // maximum pipe name
+ };
+
+ char _pipe[pipe_name_max+1];
+
+ const char* pipe() const { return _pipe; }
+ void set_pipe(const char* pipe) {
+ assert(strlen(pipe) <= pipe_name_max, "execeds maximum length of pipe name");
+ strcpy(_pipe, pipe);
+ }
+
+ HANDLE open_pipe();
+ static BOOL write_pipe(HANDLE hPipe, char* buf, int len);
+
+ Win32AttachOperation* _next;
+
+ Win32AttachOperation* next() const { return _next; }
+ void set_next(Win32AttachOperation* next) { _next = next; }
+
+ // noarg constructor as operation is preallocated
+ Win32AttachOperation() : AttachOperation("<noname>") {
+ set_pipe("<nopipe>");
+ set_next(NULL);
+ }
+
+ public:
+ void Win32AttachOperation::complete(jint result, bufferedStream* result_stream);
+};
+
+
+// preallocate the required number of operations
+int Win32AttachListener::init() {
+ _mutex = (void*)::CreateMutex(NULL, FALSE, NULL);
+ guarantee(_mutex != (HANDLE)NULL, "mutex creation failed");
+
+ _wakeup = ::CreateSemaphore(NULL, 0, 1, NULL);
+ guarantee(_wakeup != (HANDLE)NULL, "semaphore creation failed");
+
+ set_head(NULL);
+ set_tail(NULL);
+
+ // preallocate a few operations
+ set_available(NULL);
+ for (int i=0; i<preallocate_count; i++) {
+ Win32AttachOperation* op = new Win32AttachOperation();
+ op->set_next(available());
+ set_available(op);
+ }
+
+ return 0;
+}
+
+// Enqueue an operation. This is called from a native thread that is not attached to VM.
+// Also we need to be careful not to execute anything that results in more than a 4k stack.
+//
+int Win32AttachListener::enqueue(char* cmd, char* arg0, char* arg1, char* arg2, char* pipename) {
+ // listener not running
+ if (!AttachListener::is_initialized()) {
+ return ATTACH_ERROR_DISABLED;
+ }
+
+ // check that all paramteres to the operation
+ if (strlen(cmd) > AttachOperation::name_length_max) return ATTACH_ERROR_ILLEGALARG;
+ if (strlen(arg0) > AttachOperation::arg_length_max) return ATTACH_ERROR_ILLEGALARG;
+ if (strlen(arg0) > AttachOperation::arg_length_max) return ATTACH_ERROR_ILLEGALARG;
+ if (strlen(pipename) > Win32AttachOperation::pipe_name_max) return ATTACH_ERROR_ILLEGALARG;
+
+ // check for a well-formed pipename
+ if (strstr(pipename, "\\\\.\\pipe\\") != pipename) return ATTACH_ERROR_ILLEGALARG;
+
+ // grab the lock for the list
+ DWORD res = ::WaitForSingleObject(mutex(), INFINITE);
+ if (res != WAIT_OBJECT_0) {
+ return ATTACH_ERROR_INTERNAL;
+ }
+
+ // try to get an operation from the available list
+ Win32AttachOperation* op = available();
+ if (op != NULL) {
+ set_available(op->next());
+
+ // add to end (tail) of list
+ op->set_next(NULL);
+ if (tail() == NULL) {
+ set_head(op);
+ } else {
+ tail()->set_next(op);
+ }
+ set_tail(op);
+
+ op->set_name(cmd);
+ op->set_arg(0, arg0);
+ op->set_arg(1, arg1);
+ op->set_arg(2, arg2);
+ op->set_pipe(pipename);
+
+ // wakeup the thread waiting for operations
+ ::ReleaseSemaphore(wakeup(), 1, NULL);
+ }
+ ::ReleaseMutex(mutex());
+
+ return (op != NULL) ? 0 : ATTACH_ERROR_RESOURCE;
+}
+
+
+// dequeue the operation from the head of the operation list. If
+Win32AttachOperation* Win32AttachListener::dequeue() {
+ for (;;) {
+ DWORD res = ::WaitForSingleObject(wakeup(), INFINITE);
+ guarantee(res == WAIT_OBJECT_0, "wait failed");
+
+ res = ::WaitForSingleObject(mutex(), INFINITE);
+ guarantee(res == WAIT_OBJECT_0, "wait failed");
+
+ Win32AttachOperation* op = head();
+ if (op != NULL) {
+ set_head(op->next());
+ if (head() == NULL) { // list is empty
+ set_tail(NULL);
+ }
+ }
+ ::ReleaseMutex(mutex());
+
+ if (op != NULL) {
+ return op;
+ }
+ }
+}
+
+
+// open the pipe to the client
+HANDLE Win32AttachOperation::open_pipe() {
+ HANDLE hPipe;
+
+ hPipe = ::CreateFile( pipe(), // pipe name
+ GENERIC_WRITE, // write only
+ 0, // no sharing
+ NULL, // default security attributes
+ OPEN_EXISTING, // opens existing pipe
+ 0, // default attributes
+ NULL); // no template file
+
+ if (hPipe != INVALID_HANDLE_VALUE) {
+ // shouldn't happen as there is a pipe created per operation
+ if (::GetLastError() == ERROR_PIPE_BUSY) {
+ return INVALID_HANDLE_VALUE;
+ }
+ }
+ return hPipe;
+}
+
+// write to the pipe
+BOOL Win32AttachOperation::write_pipe(HANDLE hPipe, char* buf, int len) {
+ do {
+ DWORD nwrote;
+
+ BOOL fSuccess = WriteFile( hPipe, // pipe handle
+ (LPCVOID)buf, // message
+ (DWORD)len, // message length
+ &nwrote, // bytes written
+ NULL); // not overlapped
+ if (!fSuccess) {
+ return fSuccess;
+ }
+ buf += nwrote;
+ len -= nwrote;
+ }
+ while (len > 0);
+ return TRUE;
+}
+
+// Complete the operation:
+// - open the pipe to the client
+// - write the operation result (a jint)
+// - write the operation output (the result stream)
+//
+void Win32AttachOperation::complete(jint result, bufferedStream* result_stream) {
+ JavaThread* thread = JavaThread::current();
+ ThreadBlockInVM tbivm(thread);
+
+ thread->set_suspend_equivalent();
+ // cleared by handle_special_suspend_equivalent_condition() or
+ // java_suspend_self() via check_and_wait_while_suspended()
+
+ HANDLE hPipe = open_pipe();
+ if (hPipe != INVALID_HANDLE_VALUE) {
+ BOOL fSuccess;
+
+ char msg[32];
+ sprintf(msg, "%d\n", result);
+
+ fSuccess = write_pipe(hPipe, msg, (int)strlen(msg));
+ if (fSuccess) {
+ write_pipe(hPipe, (char*) result_stream->base(), (int)(result_stream->size()));
+ }
+
+ // Need to flush buffers
+ FlushFileBuffers(hPipe);
+ CloseHandle(hPipe);
+ }
+
+ DWORD res = ::WaitForSingleObject(Win32AttachListener::mutex(), INFINITE);
+ if (res == WAIT_OBJECT_0) {
+
+ // put the operation back on the available list
+ set_next(Win32AttachListener::available());
+ Win32AttachListener::set_available(this);
+
+ ::ReleaseMutex(Win32AttachListener::mutex());
+ }
+
+ // were we externally suspended while we were waiting?
+ thread->check_and_wait_while_suspended();
+}
+
+
+// AttachOperation functions
+
+AttachOperation* AttachListener::dequeue() {
+ JavaThread* thread = JavaThread::current();
+ ThreadBlockInVM tbivm(thread);
+
+ thread->set_suspend_equivalent();
+ // cleared by handle_special_suspend_equivalent_condition() or
+ // java_suspend_self() via check_and_wait_while_suspended()
+
+ AttachOperation* op = Win32AttachListener::dequeue();
+
+ // were we externally suspended while we were waiting?
+ thread->check_and_wait_while_suspended();
+
+ return op;
+}
+
+int AttachListener::pd_init() {
+ return Win32AttachListener::init();
+}
+
+// always startup on Windows NT/2000/XP
+bool AttachListener::init_at_startup() {
+ return os::win32::is_nt();
+}
+
+// no trigger mechanism on Windows to start Attach Listener lazily
+bool AttachListener::is_init_trigger() {
+ return false;
+}
+
+void AttachListener::abort() {
+ // nothing to do
+}
+
+void AttachListener::pd_data_dump() {
+ os::signal_notify(SIGBREAK);
+}
+
+AttachOperationFunctionInfo* AttachListener::pd_find_operation(const char* n) {
+ return NULL;
+}
+
+jint AttachListener::pd_set_flag(AttachOperation* op, outputStream* out) {
+ out->print_cr("flag '%s' cannot be changed", op->arg(0));
+ return JNI_ERR;
+}
+
+void AttachListener::pd_detachall() {
+ // do nothing for now
+}
+
+// Native thread started by remote client executes this.
+extern "C" {
+ JNIEXPORT jint JNICALL
+ JVM_EnqueueOperation(char* cmd, char* arg0, char* arg1, char* arg2, char* pipename) {
+ return (jint)Win32AttachListener::enqueue(cmd, arg0, arg1, arg2, pipename);
+ }
+
+} // extern