/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <errno.h>
#include <stdlib.h>
#include <sys/time.h>
#include <time.h>
#include <unistd.h>
#include "atomic.h"
#include "base/logging.h"
#include "base/time_utils.h"
#include "debugger.h"
#include "jdwp/jdwp_priv.h"
#include "scoped_thread_state_change.h"
namespace art {
namespace JDWP {
static void* StartJdwpThread(void* arg);
/*
* JdwpNetStateBase class implementation
*/
JdwpNetStateBase::JdwpNetStateBase(JdwpState* state)
: state_(state), socket_lock_("JdwpNetStateBase lock", kJdwpSocketLock) {
clientSock = -1;
wake_pipe_[0] = -1;
wake_pipe_[1] = -1;
input_count_ = 0;
awaiting_handshake_ = false;
}
JdwpNetStateBase::~JdwpNetStateBase() {
if (wake_pipe_[0] != -1) {
close(wake_pipe_[0]);
wake_pipe_[0] = -1;
}
if (wake_pipe_[1] != -1) {
close(wake_pipe_[1]);
wake_pipe_[1] = -1;
}
}
bool JdwpNetStateBase::MakePipe() {
if (pipe(wake_pipe_) == -1) {
PLOG(ERROR) << "pipe failed";
return false;
}
return true;
}
void JdwpNetStateBase::WakePipe() {
// If we might be sitting in select, kick us loose.
if (wake_pipe_[1] != -1) {
VLOG(jdwp) << "+++ writing to wake pipe";
TEMP_FAILURE_RETRY(write(wake_pipe_[1], "", 1));
}
}
void JdwpNetStateBase::ConsumeBytes(size_t count) {
CHECK_GT(count, 0U);
CHECK_LE(count, input_count_);
if (count == input_count_) {
input_count_ = 0;
return;
}
memmove(input_buffer_, input_buffer_ + count, input_count_ - count);
input_count_ -= count;
}
bool JdwpNetStateBase::HaveFullPacket() {
if (awaiting_handshake_) {
return (input_count_ >= kMagicHandshakeLen);
}
if (input_count_ < 4) {
return false;
}
uint32_t length = Get4BE(input_buffer_);
return (input_count_ >= length);
}
bool JdwpNetStateBase::IsAwaitingHandshake() {
return awaiting_handshake_;
}
void JdwpNetStateBase::SetAwaitingHandshake(bool new_state) {
awaiting_handshake_ = new_state;
}
bool JdwpNetStateBase::IsConnected() {
return clientSock >= 0;
}
// Close a connection from a debugger (which may have already dropped us).
// Resets the state so we're ready to receive a new connection.
// Only called from the JDWP thread.
void JdwpNetStateBase::Close() {
if (clientSock < 0) {
return;
}
VLOG(jdwp) << "+++ closing JDWP connection on fd " << clientSock;
close(clientSock);
clientSock = -1;
}
/*
* Write a packet of "length" bytes. Grabs a mutex to assure atomicity.
*/
ssize_t JdwpNetStateBase::WritePacket(ExpandBuf* pReply, size_t length) {
MutexLock mu(Thread::Current(), socket_lock_);
DCHECK(IsConnected()) << "Connection with debugger is closed";
DCHECK_LE(length, expandBufGetLength(pReply));
return TEMP_FAILURE_RETRY(write(clientSock, expandBufGetBuffer(pReply), length));
}
/*
* Write a buffered packet. Grabs a mutex to assure atomicity.
*/
ssize_t JdwpNetStateBase::WriteBufferedPacket(const std::vector<iovec>& iov) {
MutexLock mu(Thread::Current(), socket_lock_);
return WriteBufferedPacketLocked(iov);
}
ssize_t JdwpNetStateBase::WriteBufferedPacketLocked(const std::vector<iovec>& iov) {
socket_lock_.AssertHeld(Thread::Current());
DCHECK(IsConnected()) << "Connection with debugger is closed";
return TEMP_FAILURE_RETRY(writev(clientSock, &iov[0], iov.size()));
}
bool JdwpState::IsConnected() {
return netState != nullptr && netState->IsConnected();
}
void JdwpState::SendBufferedRequest(uint32_t type, const std::vector<iovec>& iov) {
if (!IsConnected()) {
// Can happen with some DDMS events.
VLOG(jdwp) << "Not sending JDWP packet: no debugger attached!";
return;
}
size_t expected = 0;
for (size_t i = 0; i < iov.size(); ++i) {
expected += iov[i].iov_len;
}
errno = 0;
ssize_t actual = netState->WriteBufferedPacket(iov);
if (static_cast<size_t>(actual) != expected) {
PLOG(ERROR) << StringPrintf("Failed to send JDWP packet %c%c%c%c to debugger (%zd of %zu)",
static_cast<char>(type >> 24),
static_cast<char>(type >> 16),
static_cast<char>(type >> 8),
static_cast<char>(type),
actual, expected);
}
}
void JdwpState::SendRequest(ExpandBuf* pReq) {
if (!IsConnected()) {
// Can happen with some DDMS events.
VLOG(jdwp) << "Not sending JDWP packet: no debugger attached!";
return;
}
errno = 0;
ssize_t actual = netState->WritePacket(pReq, expandBufGetLength(pReq));
if (static_cast<size_t>(actual) != expandBufGetLength(pReq)) {
PLOG(ERROR) << StringPrintf("Failed to send JDWP packet to debugger (%zd of %zu)",
actual, expandBufGetLength(pReq));
}
}
/*
* Get the next "request" serial number. We use this when sending
* packets to the debugger.
*/
uint32_t JdwpState::NextRequestSerial() {
return request_serial_++;
}
/*
* Get the next "event" serial number. We use this in the response to
* message type EventRequest.Set.
*/
uint32_t JdwpState::NextEventSerial() {
return event_serial_++;
}
JdwpState::JdwpState(const JdwpOptions* options)
: options_(options),
thread_start_lock_("JDWP thread start lock", kJdwpStartLock),
thread_start_cond_("JDWP thread start condition variable", thread_start_lock_),
pthread_(0),
thread_(nullptr),
debug_thread_started_(false),
debug_thread_id_(0),
run(false),
netState(nullptr),
attach_lock_("JDWP attach lock", kJdwpAttachLock),
attach_cond_("JDWP attach condition variable", attach_lock_),
last_activity_time_ms_(0),
request_serial_(0x10000000),
event_serial_(0x20000000),
event_list_lock_("JDWP event list lock", kJdwpEventListLock),
event_list_(nullptr),
event_list_size_(0),
jdwp_token_lock_("JDWP token lock"),
jdwp_token_cond_("JDWP token condition variable", jdwp_token_lock_),
jdwp_token_owner_thread_id_(0),
ddm_is_active_(false),
should_exit_(false),
exit_status_(0),
shutdown_lock_("JDWP shutdown lock", kJdwpShutdownLock),
shutdown_cond_("JDWP shutdown condition variable", shutdown_lock_),
processing_request_(false) {
}
/*
* Initialize JDWP.
*
* Does not return until JDWP thread is running, but may return before
* the thread is accepting network connections.
*/
JdwpState* JdwpState::Create(const JdwpOptions* options) {
Thread* self = Thread::Current();
Locks::mutator_lock_->AssertNotHeld(self);
std::unique_ptr<JdwpState> state(new JdwpState(options));
switch (options->transport) {
case kJdwpTransportSocket:
InitSocketTransport(state.get(), options);
break;
#ifdef HAVE_ANDROID_OS
case kJdwpTransportAndroidAdb:
InitAdbTransport(state.get(), options);
break;
#endif
default:
LOG(FATAL) << "Unknown transport: " << options->transport;
}
{
/*
* Grab a mutex before starting the thread. This ensures they
* won't signal the cond var before we're waiting.
*/
MutexLock thread_start_locker(self, state->thread_start_lock_);
/*
* We have bound to a port, or are trying to connect outbound to a
* debugger. Create the JDWP thread and let it continue the mission.
*/
CHECK_PTHREAD_CALL(pthread_create, (&state->pthread_, nullptr, StartJdwpThread, state.get()),
"JDWP thread");
/*
* Wait until the thread finishes basic initialization.
*/
while (!state->debug_thread_started_) {
state->thread_start_cond_.Wait(self);
}
}
if (options->suspend) {
/*
* For suspend=y, wait for the debugger to connect to us or for us to
* connect to the debugger.
*
* The JDWP thread will signal us when it connects successfully or
* times out (for timeout=xxx), so we have to check to see what happened
* when we wake up.
*/
{
ScopedThreadStateChange tsc(self, kWaitingForDebuggerToAttach);
MutexLock attach_locker(self, state->attach_lock_);
while (state->debug_thread_id_ == 0) {
state->attach_cond_.Wait(self);
}
}
if (!state->IsActive()) {
LOG(ERROR) << "JDWP connection failed";
return nullptr;
}
LOG(INFO) << "JDWP connected";
/*
* Ordinarily we would pause briefly to allow the debugger to set
* breakpoints and so on, but for "suspend=y" the VM init code will
* pause the VM when it sends the VM_START message.
*/
}
return state.release();
}
/*
* Reset all session-related state. There should not be an active connection
* to the client at this point. The rest of the VM still thinks there is
* a debugger attached.
*
* This includes freeing up the debugger event list.
*/
void JdwpState::ResetState() {
/* could reset the serial numbers, but no need to */
UnregisterAll();
{
MutexLock mu(Thread::Current(), event_list_lock_);
CHECK(event_list_ == nullptr);
}
/*
* Should not have one of these in progress. If the debugger went away
* mid-request, though, we could see this.
*/
if (jdwp_token_owner_thread_id_ != 0) {
LOG(WARNING) << "Resetting state while event in progress";
DCHECK(false);
}
}
/*
* Tell the JDWP thread to shut down. Frees "state".
*/
JdwpState::~JdwpState() {
if (netState != nullptr) {
/*
* Close down the network to inspire the thread to halt. If a request is being processed,
* we need to wait for it to finish first.
*/
{
Thread* self = Thread::Current();
MutexLock mu(self, shutdown_lock_);
while (processing_request_) {
VLOG(jdwp) << "JDWP command in progress: wait for it to finish ...";
shutdown_cond_.Wait(self);
}
VLOG(jdwp) << "JDWP shutting down net...";
netState->Shutdown();
}
if (debug_thread_started_) {
run = false;
void* threadReturn;
if (pthread_join(pthread_, &threadReturn) != 0) {
LOG(WARNING) << "JDWP thread join failed";
}
}
VLOG(jdwp) << "JDWP freeing netstate...";
delete netState;
netState = nullptr;
}
CHECK(netState == nullptr);
ResetState();
}
/*
* Are we talking to a debugger?
*/
bool JdwpState::IsActive() {
return IsConnected();
}
// Returns "false" if we encounter a connection-fatal error.
bool JdwpState::HandlePacket() {
Thread* const self = Thread::Current();
{
MutexLock mu(self, shutdown_lock_);
processing_request_ = true;
}
JdwpNetStateBase* netStateBase = netState;
CHECK(netStateBase != nullptr) << "Connection has been closed";
JDWP::Request request(netStateBase->input_buffer_, netStateBase->input_count_);
ExpandBuf* pReply = expandBufAlloc();
bool skip_reply = false;
size_t replyLength = ProcessRequest(&request, pReply, &skip_reply);
ssize_t cc = 0;
if (!skip_reply) {
cc = netStateBase->WritePacket(pReply, replyLength);
} else {
DCHECK_EQ(replyLength, 0U);
}
expandBufFree(pReply);
/*
* We processed this request and sent its reply so we can release the JDWP token.
*/
ReleaseJdwpTokenForCommand();
if (cc != static_cast<ssize_t>(replyLength)) {
PLOG(ERROR) << "Failed sending reply to debugger";
return false;
}
netStateBase->ConsumeBytes(request.GetLength());
{
MutexLock mu(self, shutdown_lock_);
processing_request_ = false;
shutdown_cond_.Broadcast(self);
}
return true;
}
/*
* Entry point for JDWP thread. The thread was created through the VM
* mechanisms, so there is a java/lang/Thread associated with us.
*/
static void* StartJdwpThread(void* arg) {
JdwpState* state = reinterpret_cast<JdwpState*>(arg);
CHECK(state != nullptr);
state->Run();
return nullptr;
}
void JdwpState::Run() {
Runtime* runtime = Runtime::Current();
CHECK(runtime->AttachCurrentThread("JDWP", true, runtime->GetSystemThreadGroup(),
!runtime->IsAotCompiler()));
VLOG(jdwp) << "JDWP: thread running";
/*
* Finish initializing, then notify the creating thread that
* we're running.
*/
thread_ = Thread::Current();
run = true;
{
MutexLock locker(thread_, thread_start_lock_);
debug_thread_started_ = true;
thread_start_cond_.Broadcast(thread_);
}
/* set the thread state to kWaitingInMainDebuggerLoop so GCs don't wait for us */
CHECK_EQ(thread_->GetState(), kNative);
Locks::mutator_lock_->AssertNotHeld(thread_);
thread_->SetState(kWaitingInMainDebuggerLoop);
/*
* Loop forever if we're in server mode, processing connections. In
* non-server mode, we bail out of the thread when the debugger drops
* us.
*
* We broadcast a notification when a debugger attaches, after we
* successfully process the handshake.
*/
while (run) {
if (options_->server) {
/*
* Block forever, waiting for a connection. To support the
* "timeout=xxx" option we'll need to tweak this.
*/
if (!netState->Accept()) {
break;
}
} else {
/*
* If we're not acting as a server, we need to connect out to the
* debugger. To support the "timeout=xxx" option we need to
* have a timeout if the handshake reply isn't received in a
* reasonable amount of time.
*/
if (!netState->Establish(options_)) {
/* wake anybody who was waiting for us to succeed */
MutexLock mu(thread_, attach_lock_);
debug_thread_id_ = static_cast<ObjectId>(-1);
attach_cond_.Broadcast(thread_);
break;
}
}
/* prep debug code to handle the new connection */
Dbg::Connected();
/* process requests until the debugger drops */
bool first = true;
while (!Dbg::IsDisposed()) {
// sanity check -- shouldn't happen?
CHECK_EQ(thread_->GetState(), kWaitingInMainDebuggerLoop);
if (!netState->ProcessIncoming()) {
/* blocking read */
break;
}
if (should_exit_) {
exit(exit_status_);
}
if (first && !netState->IsAwaitingHandshake()) {
/* handshake worked, tell the interpreter that we're active */
first = false;
/* set thread ID; requires object registry to be active */
{
ScopedObjectAccess soa(thread_);
debug_thread_id_ = Dbg::GetThreadSelfId();
}
/* wake anybody who's waiting for us */
MutexLock mu(thread_, attach_lock_);
attach_cond_.Broadcast(thread_);
}
}
netState->Close();
if (ddm_is_active_) {
ddm_is_active_ = false;
/* broadcast the disconnect; must be in RUNNING state */
thread_->TransitionFromSuspendedToRunnable();
Dbg::DdmDisconnected();
thread_->TransitionFromRunnableToSuspended(kWaitingInMainDebuggerLoop);
}
{
ScopedObjectAccess soa(thread_);
// Release session state, e.g. remove breakpoint instructions.
ResetState();
}
// Tell the rest of the runtime that the debugger is no longer around.
Dbg::Disconnected();
/* if we had threads suspended, resume them now */
Dbg::UndoDebuggerSuspensions();
/* if we connected out, this was a one-shot deal */
if (!options_->server) {
run = false;
}
}
/* back to native, for thread shutdown */
CHECK_EQ(thread_->GetState(), kWaitingInMainDebuggerLoop);
thread_->SetState(kNative);
VLOG(jdwp) << "JDWP: thread detaching and exiting...";
runtime->DetachCurrentThread();
}
void JdwpState::NotifyDdmsActive() {
if (!ddm_is_active_) {
ddm_is_active_ = true;
Dbg::DdmConnected();
}
}
Thread* JdwpState::GetDebugThread() {
return thread_;
}
/*
* Support routines for waitForDebugger().
*
* We can't have a trivial "waitForDebugger" function that returns the
* instant the debugger connects, because we run the risk of executing code
* before the debugger has had a chance to configure breakpoints or issue
* suspend calls. It would be nice to just sit in the suspended state, but
* most debuggers don't expect any threads to be suspended when they attach.
*
* There's no JDWP event we can post to tell the debugger, "we've stopped,
* and we like it that way". We could send a fake breakpoint, which should
* cause the debugger to immediately send a resume, but the debugger might
* send the resume immediately or might throw an exception of its own upon
* receiving a breakpoint event that it didn't ask for.
*
* What we really want is a "wait until the debugger is done configuring
* stuff" event. We can approximate this with a "wait until the debugger
* has been idle for a brief period".
*/
/*
* Return the time, in milliseconds, since the last debugger activity.
*
* Returns -1 if no debugger is attached, or 0 if we're in the middle of
* processing a debugger request.
*/
int64_t JdwpState::LastDebuggerActivity() {
if (!Dbg::IsDebuggerActive()) {
LOG(WARNING) << "no active debugger";
return -1;
}
int64_t last = last_activity_time_ms_.LoadSequentiallyConsistent();
/* initializing or in the middle of something? */
if (last == 0) {
VLOG(jdwp) << "+++ last=busy";
return 0;
}
/* now get the current time */
int64_t now = MilliTime();
CHECK_GE(now, last);
VLOG(jdwp) << "+++ debugger interval=" << (now - last);
return now - last;
}
void JdwpState::ExitAfterReplying(int exit_status) {
LOG(WARNING) << "Debugger told VM to exit with status " << exit_status;
should_exit_ = true;
exit_status_ = exit_status;
}
std::ostream& operator<<(std::ostream& os, const JdwpLocation& rhs) {
os << "JdwpLocation["
<< Dbg::GetClassName(rhs.class_id) << "." << Dbg::GetMethodName(rhs.method_id)
<< "@" << StringPrintf("%#" PRIx64, rhs.dex_pc) << " " << rhs.type_tag << "]";
return os;
}
bool operator==(const JdwpLocation& lhs, const JdwpLocation& rhs) {
return lhs.dex_pc == rhs.dex_pc && lhs.method_id == rhs.method_id &&
lhs.class_id == rhs.class_id && lhs.type_tag == rhs.type_tag;
}
bool operator!=(const JdwpLocation& lhs, const JdwpLocation& rhs) {
return !(lhs == rhs);
}
bool operator==(const JdwpOptions& lhs, const JdwpOptions& rhs) {
if (&lhs == &rhs) {
return true;
}
return lhs.transport == rhs.transport &&
lhs.server == rhs.server &&
lhs.suspend == rhs.suspend &&
lhs.host == rhs.host &&
lhs.port == rhs.port;
}
} // namespace JDWP
} // namespace art