jdk8-mips64-public/hotspot: src/os/windows/vm/attachListener

src/os/windows/vm/attachListener_windows.cpp@c18cbe5936b8 (annotated)

src/os/windows/vm/attachListener_windows.cpp

Thu, 27 May 2010 19:08:38 -0700

author: trims
date: Thu, 27 May 2010 19:08:38 -0700
changeset 1907: c18cbe5936b8
parent 435: a61af66fc99e
child 2314: f95d63e2154a
permissions: -rw-r--r--

6941466: Oracle rebranding changes for Hotspot repositories
Summary: Change all the Sun copyrights to Oracle copyright
Reviewed-by: ohair

 /*
  * Copyright (c) 2005, 2006, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.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
 ,              // no sharing
                         NULL,           // default security attributes
                         OPEN_EXISTING,  // opens existing pipe
 ,              // 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

Mercurial > jdk8-mips64-public > hotspot / annotate

src/os/windows/vm/attachListener_windows.cpp@c18cbe5936b8 (annotated)

src/os/windows/vm/attachListener_windows.cpp