Mercurial > hg > truffle
diff src/os/windows/vm/attachListener_windows.cpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | c18cbe5936b8 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/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