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NativeProcessLinux: Merge operation and monitor threads 

Summary:
This commit moves the functionality of the operation thread into the new monitor thread. This is
required to avoid a kernel race between the two threads and I believe it actually makes the code
cleaner.

Test Plan: Ran the test suite a couple of times, no regressions.

Reviewers: ovyalov, tberghammer, vharron

Subscribers: tberghammer, lldb-commits

Differential Revision: http://reviews.llvm.org/D9080

llvm-svn: 235304
This commit is contained in:
Pavel Labath 2015-04-20 13:53:49 +00:00
parent 4ba9af1141
commit bd7cbc5a97
3 changed files with 223 additions and 417 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

563
lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
View File

@ -146,8 +146,6 @@ using namespace llvm;
// Private bits we only need internally.
namespace
{
static void * const EXIT_OPERATION = nullptr;
const UnixSignals&
GetUnixSignals ()
{
@ -1074,9 +1072,45 @@ namespace
} // end of anonymous namespace
// Simple helper function to ensure flags are enabled on the given file
// descriptor.
static Error
EnsureFDFlags(int fd, int flags)
{
Error error;
int status = fcntl(fd, F_GETFL);
if (status == -1)
{
error.SetErrorToErrno();
return error;
}
if (fcntl(fd, F_SETFL, status | flags) == -1)
{
error.SetErrorToErrno();
return error;
}
return error;
}
// This class encapsulates the privileged thread which performs all ptrace and wait operations on
// the inferior. The thread consists of a main loop which waits for events and processes them
// - SIGCHLD (delivered over a signalfd file descriptor): These signals notify us of events in
// the inferior process. Upon receiving this signal we do a waitpid to get more information
// and dispatch to NativeProcessLinux::MonitorCallback.
// - requests for ptrace operations: These initiated via the DoOperation method, which funnels
// them to the Monitor thread via m_operation member. The Monitor thread is signaled over a
// pipe, and the completion of the operation is signalled over the semaphore.
// - thread exit event: this is signaled from the Monitor destructor by closing the write end
// of the command pipe.
class NativeProcessLinux::Monitor {
private:
::pid_t m_child_pid;
// The initial monitor operation (launch or attach). It returns a inferior process id.
std::unique_ptr<InitialOperation> m_initial_operation_up;
::pid_t m_child_pid = -1;
NativeProcessLinux * m_native_process;
enum { READ, WRITE };
@ -1084,6 +1118,14 @@ private:
int m_signal_fd = -1;
HostThread m_thread;
// current operation which must be executed on the priviliged thread
Mutex m_operation_mutex;
Operation *m_operation = nullptr;
sem_t m_operation_sem;
Error m_operation_error;
static constexpr char operation_command = 'o';
void
HandleSignals();
@ -1100,17 +1142,26 @@ private:
static void *
RunMonitor(void *arg);
Error
WaitForOperation();
public:
// Takes ownership of command_fd.
Monitor(::pid_t child_pid, NativeProcessLinux *native_process)
: m_child_pid(-getpgid(child_pid)), m_native_process(native_process)
{}
Monitor(const InitialOperation &initial_operation,
NativeProcessLinux *native_process)
: m_initial_operation_up(new InitialOperation(initial_operation)),
m_native_process(native_process)
{
sem_init(&m_operation_sem, 0, 0);
}
~Monitor();
Error
Initialize();
void
DoOperation(Operation *op);
};
constexpr char NativeProcessLinux::Monitor::operation_command;
Error
NativeProcessLinux::Monitor::Initialize()
@ -1137,11 +1188,37 @@ NativeProcessLinux::Monitor::Initialize()
return error;
}
m_thread = ThreadLauncher::LaunchThread("monitor", Monitor::RunMonitor, this, nullptr);
if ((error = EnsureFDFlags(m_pipefd[READ], O_NONBLOCK)).Fail()) {
return error;
}
static const char g_thread_name[] = "lldb.process.nativelinux.monitor";
m_thread = ThreadLauncher::LaunchThread(g_thread_name, Monitor::RunMonitor, this, nullptr);
if (!m_thread.IsJoinable())
return Error("Failed to create monitor thread for NativeProcessLinux.");
return error;
// Wait for initial operation to complete.
return WaitForOperation();
}
void
NativeProcessLinux::Monitor::DoOperation(Operation *op)
{
if (m_thread.EqualsThread(pthread_self())) {
// If we're on the Monitor thread, we can simply execute the operation.
op->Execute(m_native_process);
return;
}
// Otherwise we need to pass the operation to the Monitor thread so it can handle it.
Mutex::Locker lock(m_operation_mutex);
m_operation = op;
// notify the thread that an operation is ready to be processed
write(m_pipefd[WRITE], &operation_command, sizeof operation_command);
WaitForOperation();
}
NativeProcessLinux::Monitor::~Monitor()
@ -1154,6 +1231,7 @@ NativeProcessLinux::Monitor::~Monitor()
close(m_pipefd[READ]);
if (m_signal_fd >= 0)
close(m_signal_fd);
sem_destroy(&m_operation_sem);
}
void
@ -1280,15 +1358,31 @@ NativeProcessLinux::Monitor::HandleCommands()
log->Printf("NativeProcessLinux::Monitor::%s exit command received, exiting...", __FUNCTION__);
return true; // We are done.
}
switch (command)
{
case operation_command:
m_operation->Execute(m_native_process);
// notify calling thread that operation is complete
sem_post(&m_operation_sem);
break;
default:
if (log)
log->Printf("NativeProcessLinux::Monitor::%s received unknown command '%c'",
__FUNCTION__, command);
}
}
}
void
NativeProcessLinux::Monitor::MainLoop()
{
::pid_t child_pid = (*m_initial_operation_up)(m_operation_error);
m_initial_operation_up.reset();
m_child_pid = -getpgid(child_pid),
sem_post(&m_operation_sem);
while (true)
{
fd_set fds;
@ -1321,6 +1415,22 @@ NativeProcessLinux::Monitor::MainLoop()
}
}
Error
NativeProcessLinux::Monitor::WaitForOperation()
{
Error error;
while (sem_wait(&m_operation_sem) != 0)
{
if (errno == EINTR)
continue;
error.SetErrorToErrno();
return error;
}
return m_operation_error;
}
void *
NativeProcessLinux::Monitor::RunMonitor(void *arg)
{
@ -1329,41 +1439,7 @@ NativeProcessLinux::Monitor::RunMonitor(void *arg)
}
// Simple helper function to ensure flags are enabled on the given file
// descriptor.
static bool
EnsureFDFlags(int fd, int flags, Error &error)
{
int status;
if ((status = fcntl(fd, F_GETFL)) == -1)
{
error.SetErrorToErrno();
return false;
}
if (fcntl(fd, F_SETFL, status | flags) == -1)
{
error.SetErrorToErrno();
return false;
}
return true;
}
NativeProcessLinux::OperationArgs::OperationArgs(NativeProcessLinux *monitor)
: m_monitor(monitor)
{
sem_init(&m_semaphore, 0, 0);
}
NativeProcessLinux::OperationArgs::~OperationArgs()
{
sem_destroy(&m_semaphore);
}
NativeProcessLinux::LaunchArgs::LaunchArgs(NativeProcessLinux *monitor,
Module *module,
NativeProcessLinux::LaunchArgs::LaunchArgs(Module *module,
char const **argv,
char const **envp,
const std::string &stdin_path,
@ -1371,8 +1447,7 @@ NativeProcessLinux::LaunchArgs::LaunchArgs(NativeProcessLinux *monitor,
const std::string &stderr_path,
const char *working_dir,
const ProcessLaunchInfo &launch_info)
: OperationArgs(monitor),
m_module(module),
: m_module(module),
m_argv(argv),
m_envp(envp),
m_stdin_path(stdin_path),
@ -1386,13 +1461,6 @@ NativeProcessLinux::LaunchArgs::LaunchArgs(NativeProcessLinux *monitor,
NativeProcessLinux::LaunchArgs::~LaunchArgs()
{ }
NativeProcessLinux::AttachArgs::AttachArgs(NativeProcessLinux *monitor,
lldb::pid_t pid)
: OperationArgs(monitor), m_pid(pid) { }
NativeProcessLinux::AttachArgs::~AttachArgs()
{ }
// -----------------------------------------------------------------------------
// Public Static Methods
// -----------------------------------------------------------------------------
@ -1546,11 +1614,6 @@ NativeProcessLinux::AttachToProcess (
NativeProcessLinux::NativeProcessLinux () :
NativeProcessProtocol (LLDB_INVALID_PROCESS_ID),
m_arch (),
m_operation_thread (),
m_operation (nullptr),
m_operation_mutex (),
m_operation_pending (),
m_operation_done (),
m_supports_mem_region (eLazyBoolCalculate),
m_mem_region_cache (),
m_mem_region_cache_mutex (),
@ -1560,17 +1623,9 @@ NativeProcessLinux::NativeProcessLinux () :
}
//------------------------------------------------------------------------------
/// The basic design of the NativeProcessLinux is built around two threads.
///
/// One thread (@see SignalThread) simply blocks on a call to waitpid() looking
/// for changes in the debugee state. When a change is detected a
/// ProcessMessage is sent to the associated ProcessLinux instance. This thread
/// "drives" state changes in the debugger.
///
/// The second thread (@see OperationThread) is responsible for two things 1)
/// launching or attaching to the inferior process, and then 2) servicing
/// operations such as register reads/writes, stepping, etc. See the comments
/// on the Operation class for more info as to why this is needed.
// NativeProcessLinux spawns a new thread which performs all operations on the inferior process.
// Refer to Monitor and Operation classes to see why this is necessary.
//------------------------------------------------------------------------------
void
NativeProcessLinux::LaunchInferior (
Module *module,
@ -1590,45 +1645,17 @@ NativeProcessLinux::LaunchInferior (
std::unique_ptr<LaunchArgs> args(
new LaunchArgs(
this, module, argv, envp,
module, argv, envp,
stdin_path, stdout_path, stderr_path,
working_dir, launch_info));
sem_init (&m_operation_pending, 0, 0);
sem_init (&m_operation_done, 0, 0);
StartLaunchOpThread (args.get(), error);
StartMonitorThread ([&] (Error &e) { return Launch(args.get(), e); }, error);
if (!error.Success ())
return;
error = StartCoordinatorThread ();
if (!error.Success ())
return;
WAIT_AGAIN:
// Wait for the operation thread to initialize.
if (sem_wait(&args->m_semaphore))
{
if (errno == EINTR)
goto WAIT_AGAIN;
else
{
error.SetErrorToErrno();
return;
}
}
// Check that the launch was a success.
if (!args->m_error.Success())
{
StopOpThread();
StopCoordinatorThread ();
error = args->m_error;
return;
}
// Finally, start monitoring the child process for change in state.
StartMonitorThread(error);
}
void
@ -1675,43 +1702,13 @@ NativeProcessLinux::AttachToInferior (lldb::pid_t pid, Error &error)
m_pid = pid;
SetState(eStateAttaching);
sem_init (&m_operation_pending, 0, 0);
sem_init (&m_operation_done, 0, 0);
std::unique_ptr<AttachArgs> args (new AttachArgs (this, pid));
StartAttachOpThread(args.get (), error);
StartMonitorThread ([=] (Error &e) { return Attach(pid, e); }, error);
if (!error.Success ())
return;
error = StartCoordinatorThread ();
if (!error.Success ())
return;
WAIT_AGAIN:
// Wait for the operation thread to initialize.
if (sem_wait (&args->m_semaphore))
{
if (errno == EINTR)
goto WAIT_AGAIN;
else
{
error.SetErrorToErrno ();
return;
}
}
// Check that the attach was a success.
if (!args->m_error.Success ())
{
StopOpThread ();
StopCoordinatorThread ();
error = args->m_error;
return;
}
// Finally, start monitoring the child process for change in state.
StartMonitorThread(error);
}
void
@ -1720,43 +1717,10 @@ NativeProcessLinux::Terminate ()
StopMonitor();
}
//------------------------------------------------------------------------------
// Thread setup and tear down.
void
NativeProcessLinux::StartLaunchOpThread(LaunchArgs *args, Error &error)
{
static const char *g_thread_name = "lldb.process.nativelinux.operation";
if (m_operation_thread.IsJoinable())
return;
m_operation_thread = ThreadLauncher::LaunchThread(g_thread_name, LaunchOpThread, args, &error);
}
void *
NativeProcessLinux::LaunchOpThread(void *arg)
{
LaunchArgs *args = static_cast<LaunchArgs*>(arg);
if (!Launch(args)) {
sem_post(&args->m_semaphore);
return NULL;
}
ServeOperation(args);
return NULL;
}
bool
NativeProcessLinux::Launch(LaunchArgs *args)
::pid_t
NativeProcessLinux::Launch(LaunchArgs *args, Error &error)
{
assert (args && "null args");
if (!args)
return false;
NativeProcessLinux *monitor = args->m_monitor;
assert (monitor && "monitor is NULL");
const char **argv = args->m_argv;
const char **envp = args->m_envp;
@ -1776,9 +1740,9 @@ NativeProcessLinux::Launch(LaunchArgs *args)
if ((pid = terminal.Fork(err_str, err_len)) == static_cast<lldb::pid_t> (-1))
{
args->m_error.SetErrorToGenericError();
args->m_error.SetErrorString("Process fork failed.");
return false;
error.SetErrorToGenericError();
error.SetErrorStringWithFormat("Process fork failed: %s", err_str);
return -1;
}
// Recognized child exit status codes.
@ -1799,8 +1763,8 @@ NativeProcessLinux::Launch(LaunchArgs *args)
// send log info to parent re: launch status, in place of the log lines removed here.
// Start tracing this child that is about to exec.
PTRACE(PTRACE_TRACEME, 0, nullptr, nullptr, 0, args->m_error);
if (args->m_error.Fail())
PTRACE(PTRACE_TRACEME, 0, nullptr, nullptr, 0, error);
if (error.Fail())
exit(ePtraceFailed);
// terminal has already dupped the tty descriptors to stdin/out/err.
@ -1878,46 +1842,46 @@ NativeProcessLinux::Launch(LaunchArgs *args)
int status;
if ((wpid = waitpid(pid, &status, 0)) < 0)
{
args->m_error.SetErrorToErrno();
error.SetErrorToErrno();
if (log)
log->Printf ("NativeProcessLinux::%s waitpid for inferior failed with %s", __FUNCTION__, args->m_error.AsCString ());
log->Printf ("NativeProcessLinux::%s waitpid for inferior failed with %s",
__FUNCTION__, error.AsCString ());
// Mark the inferior as invalid.
// FIXME this could really use a new state - eStateLaunchFailure. For now, using eStateInvalid.
monitor->SetState (StateType::eStateInvalid);
SetState (StateType::eStateInvalid);
return false;
return -1;
}
else if (WIFEXITED(status))
{
// open, dup or execve likely failed for some reason.
args->m_error.SetErrorToGenericError();
error.SetErrorToGenericError();
switch (WEXITSTATUS(status))
{
case ePtraceFailed:
args->m_error.SetErrorString("Child ptrace failed.");
error.SetErrorString("Child ptrace failed.");
break;
case eDupStdinFailed:
args->m_error.SetErrorString("Child open stdin failed.");
error.SetErrorString("Child open stdin failed.");
break;
case eDupStdoutFailed:
args->m_error.SetErrorString("Child open stdout failed.");
error.SetErrorString("Child open stdout failed.");
break;
case eDupStderrFailed:
args->m_error.SetErrorString("Child open stderr failed.");
error.SetErrorString("Child open stderr failed.");
break;
case eChdirFailed:
args->m_error.SetErrorString("Child failed to set working directory.");
error.SetErrorString("Child failed to set working directory.");
break;
case eExecFailed:
args->m_error.SetErrorString("Child exec failed.");
error.SetErrorString("Child exec failed.");
break;
case eSetGidFailed:
args->m_error.SetErrorString("Child setgid failed.");
error.SetErrorString("Child setgid failed.");
break;
default:
args->m_error.SetErrorString("Child returned unknown exit status.");
error.SetErrorString("Child returned unknown exit status.");
break;
}
@ -1930,9 +1894,9 @@ NativeProcessLinux::Launch(LaunchArgs *args)
// Mark the inferior as invalid.
// FIXME this could really use a new state - eStateLaunchFailure. For now, using eStateInvalid.
monitor->SetState (StateType::eStateInvalid);
SetState (StateType::eStateInvalid);
return false;
return -1;
}
assert(WIFSTOPPED(status) && (wpid == static_cast< ::pid_t> (pid)) &&
"Could not sync with inferior process.");
@ -1940,102 +1904,73 @@ NativeProcessLinux::Launch(LaunchArgs *args)
if (log)
log->Printf ("NativeProcessLinux::%s inferior started, now in stopped state", __FUNCTION__);
args->m_error = SetDefaultPtraceOpts(pid);
if (args->m_error.Fail())
error = SetDefaultPtraceOpts(pid);
if (error.Fail())
{
if (log)
log->Printf ("NativeProcessLinux::%s inferior failed to set default ptrace options: %s",
__FUNCTION__,
args->m_error.AsCString ());
__FUNCTION__, error.AsCString ());
// Mark the inferior as invalid.
// FIXME this could really use a new state - eStateLaunchFailure. For now, using eStateInvalid.
monitor->SetState (StateType::eStateInvalid);
SetState (StateType::eStateInvalid);
return false;
return -1;
}
// Release the master terminal descriptor and pass it off to the
// NativeProcessLinux instance. Similarly stash the inferior pid.
monitor->m_terminal_fd = terminal.ReleaseMasterFileDescriptor();
monitor->m_pid = pid;
m_terminal_fd = terminal.ReleaseMasterFileDescriptor();
m_pid = pid;
// Set the terminal fd to be in non blocking mode (it simplifies the
// implementation of ProcessLinux::GetSTDOUT to have a non-blocking
// descriptor to read from).
if (!EnsureFDFlags(monitor->m_terminal_fd, O_NONBLOCK, args->m_error))
error = EnsureFDFlags(m_terminal_fd, O_NONBLOCK);
if (error.Fail())
{
if (log)
log->Printf ("NativeProcessLinux::%s inferior EnsureFDFlags failed for ensuring terminal O_NONBLOCK setting: %s",
__FUNCTION__,
args->m_error.AsCString ());
__FUNCTION__, error.AsCString ());
// Mark the inferior as invalid.
// FIXME this could really use a new state - eStateLaunchFailure. For now, using eStateInvalid.
monitor->SetState (StateType::eStateInvalid);
SetState (StateType::eStateInvalid);
return false;
return -1;
}
if (log)
log->Printf ("NativeProcessLinux::%s() adding pid = %" PRIu64, __FUNCTION__, pid);
thread_sp = monitor->AddThread (pid);
thread_sp = AddThread (pid);
assert (thread_sp && "AddThread() returned a nullptr thread");
monitor->NotifyThreadCreateStopped (pid);
NotifyThreadCreateStopped (pid);
std::static_pointer_cast<NativeThreadLinux> (thread_sp)->SetStoppedBySignal (SIGSTOP);
// Let our process instance know the thread has stopped.
monitor->SetCurrentThreadID (thread_sp->GetID ());
monitor->SetState (StateType::eStateStopped);
SetCurrentThreadID (thread_sp->GetID ());
SetState (StateType::eStateStopped);
if (log)
{
if (args->m_error.Success ())
if (error.Success ())
{
log->Printf ("NativeProcessLinux::%s inferior launching succeeded", __FUNCTION__);
}
else
{
log->Printf ("NativeProcessLinux::%s inferior launching failed: %s",
__FUNCTION__,
args->m_error.AsCString ());
__FUNCTION__, error.AsCString ());
return -1;
}
}
return args->m_error.Success();
return pid;
}
void
NativeProcessLinux::StartAttachOpThread(AttachArgs *args, Error &error)
::pid_t
NativeProcessLinux::Attach(lldb::pid_t pid, Error &error)
{
static const char *g_thread_name = "lldb.process.linux.operation";
if (m_operation_thread.IsJoinable())
return;
m_operation_thread = ThreadLauncher::LaunchThread(g_thread_name, AttachOpThread, args, &error);
}
void *
NativeProcessLinux::AttachOpThread(void *arg)
{
AttachArgs *args = static_cast<AttachArgs*>(arg);
if (!Attach(args)) {
sem_post(&args->m_semaphore);
return nullptr;
}
ServeOperation(args);
return nullptr;
}
bool
NativeProcessLinux::Attach(AttachArgs *args)
{
lldb::pid_t pid = args->m_pid;
NativeProcessLinux *monitor = args->m_monitor;
lldb::ThreadSP inferior;
Log *log (GetLogIfAllCategoriesSet (LIBLLDB_LOG_PROCESS));
@ -2043,9 +1978,9 @@ NativeProcessLinux::Attach(AttachArgs *args)
Host::TidMap tids_to_attach;
if (pid <= 1)
{
args->m_error.SetErrorToGenericError();
args->m_error.SetErrorString("Attaching to process 1 is not allowed.");
goto FINISH;
error.SetErrorToGenericError();
error.SetErrorString("Attaching to process 1 is not allowed.");
return -1;
}
while (Host::FindProcessThreads(pid, tids_to_attach))
@ -2059,18 +1994,18 @@ NativeProcessLinux::Attach(AttachArgs *args)
// Attach to the requested process.
// An attach will cause the thread to stop with a SIGSTOP.
PTRACE(PTRACE_ATTACH, tid, nullptr, nullptr, 0, args->m_error);
if (args->m_error.Fail())
PTRACE(PTRACE_ATTACH, tid, nullptr, nullptr, 0, error);
if (error.Fail())
{
// No such thread. The thread may have exited.
// More error handling may be needed.
if (args->m_error.GetError() == ESRCH)
if (error.GetError() == ESRCH)
{
it = tids_to_attach.erase(it);
continue;
}
else
goto FINISH;
return -1;
}
int status;
@ -2087,15 +2022,14 @@ NativeProcessLinux::Attach(AttachArgs *args)
}
else
{
args->m_error.SetErrorToErrno();
goto FINISH;
error.SetErrorToErrno();
return -1;
}
}
args->m_error = SetDefaultPtraceOpts(tid);
if (args->m_error.Fail())
goto FINISH;
error = SetDefaultPtraceOpts(tid);
if (error.Fail())
return -1;
if (log)
log->Printf ("NativeProcessLinux::%s() adding tid = %" PRIu64, __FUNCTION__, tid);
@ -2103,13 +2037,13 @@ NativeProcessLinux::Attach(AttachArgs *args)
it->second = true;
// Create the thread, mark it as stopped.
NativeThreadProtocolSP thread_sp (monitor->AddThread (static_cast<lldb::tid_t> (tid)));
NativeThreadProtocolSP thread_sp (AddThread (static_cast<lldb::tid_t> (tid)));
assert (thread_sp && "AddThread() returned a nullptr");
// This will notify this is a new thread and tell the system it is stopped.
monitor->NotifyThreadCreateStopped (tid);
NotifyThreadCreateStopped (tid);
std::static_pointer_cast<NativeThreadLinux> (thread_sp)->SetStoppedBySignal (SIGSTOP);
monitor->SetCurrentThreadID (thread_sp->GetID ());
SetCurrentThreadID (thread_sp->GetID ());
}
// move the loop forward
@ -2119,18 +2053,18 @@ NativeProcessLinux::Attach(AttachArgs *args)
if (tids_to_attach.size() > 0)
{
monitor->m_pid = pid;
m_pid = pid;
// Let our process instance know the thread has stopped.
monitor->SetState (StateType::eStateStopped);
SetState (StateType::eStateStopped);
}
else
{
args->m_error.SetErrorToGenericError();
args->m_error.SetErrorString("No such process.");
error.SetErrorToGenericError();
error.SetErrorString("No such process.");
return -1;
}
FINISH:
return args->m_error.Success();
return pid;
}
Error
@ -3669,67 +3603,11 @@ NativeProcessLinux::GetCrashReasonForSIGBUS(const siginfo_t *info)
}
#endif
void
NativeProcessLinux::ServeOperation(OperationArgs *args)
{
NativeProcessLinux *monitor = args->m_monitor;
// We are finised with the arguments and are ready to go. Sync with the
// parent thread and start serving operations on the inferior.
sem_post(&args->m_semaphore);
for(;;)
{
// wait for next pending operation
if (sem_wait(&monitor->m_operation_pending))
{
if (errno == EINTR)
continue;
assert(false && "Unexpected errno from sem_wait");
}
// EXIT_OPERATION used to stop the operation thread because Cancel() isn't supported on
// android. We don't have to send a post to the m_operation_done semaphore because in this
// case the synchronization is achieved by a Join() call
if (monitor->m_operation == EXIT_OPERATION)
break;
static_cast<Operation*>(monitor->m_operation)->Execute(monitor);
// notify calling thread that operation is complete
sem_post(&monitor->m_operation_done);
}
}
void
NativeProcessLinux::DoOperation(void *op)
{
Mutex::Locker lock(m_operation_mutex);
m_operation = op;
// notify operation thread that an operation is ready to be processed
sem_post(&m_operation_pending);
// Don't wait for the operation to complete in case of an exit operation. The operation thread
// will exit without posting to the semaphore
if (m_operation == EXIT_OPERATION)
return;
// wait for operation to complete
while (sem_wait(&m_operation_done))
{
if (errno == EINTR)
continue;
assert(false && "Unexpected errno from sem_wait");
}
}
Error
NativeProcessLinux::ReadMemory (lldb::addr_t addr, void *buf, lldb::addr_t size, lldb::addr_t &bytes_read)
{
ReadOperation op(addr, buf, size, bytes_read);
DoOperation(&op);
m_monitor_up->DoOperation(&op);
return op.GetError ();
}
@ -3737,7 +3615,7 @@ Error
NativeProcessLinux::WriteMemory (lldb::addr_t addr, const void *buf, lldb::addr_t size, lldb::addr_t &bytes_written)
{
WriteOperation op(addr, buf, size, bytes_written);
DoOperation(&op);
m_monitor_up->DoOperation(&op);
return op.GetError ();
}
@ -3746,7 +3624,7 @@ NativeProcessLinux::ReadRegisterValue(lldb::tid_t tid, uint32_t offset, const ch
uint32_t size, RegisterValue &value)
{
ReadRegOperation op(tid, offset, reg_name, value);
DoOperation(&op);
m_monitor_up->DoOperation(&op);
return op.GetError();
}
@ -3755,7 +3633,7 @@ NativeProcessLinux::WriteRegisterValue(lldb::tid_t tid, unsigned offset,
const char* reg_name, const RegisterValue &value)
{
WriteRegOperation op(tid, offset, reg_name, value);
DoOperation(&op);
m_monitor_up->DoOperation(&op);
return op.GetError();
}
@ -3763,7 +3641,7 @@ Error
NativeProcessLinux::ReadGPR(lldb::tid_t tid, void *buf, size_t buf_size)
{
ReadGPROperation op(tid, buf, buf_size);
DoOperation(&op);
m_monitor_up->DoOperation(&op);
return op.GetError();
}
@ -3771,7 +3649,7 @@ Error
NativeProcessLinux::ReadFPR(lldb::tid_t tid, void *buf, size_t buf_size)
{
ReadFPROperation op(tid, buf, buf_size);
DoOperation(&op);
m_monitor_up->DoOperation(&op);
return op.GetError();
}
@ -3779,7 +3657,7 @@ Error
NativeProcessLinux::ReadRegisterSet(lldb::tid_t tid, void *buf, size_t buf_size, unsigned int regset)
{
ReadRegisterSetOperation op(tid, buf, buf_size, regset);
DoOperation(&op);
m_monitor_up->DoOperation(&op);
return op.GetError();
}
@ -3787,7 +3665,7 @@ Error
NativeProcessLinux::WriteGPR(lldb::tid_t tid, void *buf, size_t buf_size)
{
WriteGPROperation op(tid, buf, buf_size);
DoOperation(&op);
m_monitor_up->DoOperation(&op);
return op.GetError();
}
@ -3795,7 +3673,7 @@ Error
NativeProcessLinux::WriteFPR(lldb::tid_t tid, void *buf, size_t buf_size)
{
WriteFPROperation op(tid, buf, buf_size);
DoOperation(&op);
m_monitor_up->DoOperation(&op);
return op.GetError();
}
@ -3803,7 +3681,7 @@ Error
NativeProcessLinux::WriteRegisterSet(lldb::tid_t tid, void *buf, size_t buf_size, unsigned int regset)
{
WriteRegisterSetOperation op(tid, buf, buf_size, regset);
DoOperation(&op);
m_monitor_up->DoOperation(&op);
return op.GetError();
}
@ -3816,7 +3694,7 @@ NativeProcessLinux::Resume (lldb::tid_t tid, uint32_t signo)
log->Printf ("NativeProcessLinux::%s() resuming thread = %" PRIu64 " with signal %s", __FUNCTION__, tid,
GetUnixSignals().GetSignalAsCString (signo));
ResumeOperation op (tid, signo);
DoOperation (&op);
m_monitor_up->DoOperation (&op);
if (log)
log->Printf ("NativeProcessLinux::%s() resuming thread = %" PRIu64 " result = %s", __FUNCTION__, tid, op.GetError().Success() ? "true" : "false");
return op.GetError();
@ -3991,7 +3869,7 @@ Error
NativeProcessLinux::SingleStep(lldb::tid_t tid, uint32_t signo)
{
SingleStepOperation op(tid, signo);
DoOperation(&op);
m_monitor_up->DoOperation(&op);
return op.GetError();
}
@ -4001,7 +3879,7 @@ Error
NativeProcessLinux::GetSignalInfo(lldb::tid_t tid, void *siginfo)
{
SiginfoOperation op(tid, siginfo);
DoOperation(&op);
m_monitor_up->DoOperation(&op);
return op.GetError();
}
@ -4009,7 +3887,7 @@ Error
NativeProcessLinux::GetEventMessage(lldb::tid_t tid, unsigned long *message)
{
EventMessageOperation op(tid, message);
DoOperation(&op);
m_monitor_up->DoOperation(&op);
return op.GetError();
}
@ -4020,7 +3898,7 @@ NativeProcessLinux::Detach(lldb::tid_t tid)
return Error();
DetachOperation op(tid);
DoOperation(&op);
m_monitor_up->DoOperation(&op);
return op.GetError();
}
@ -4039,9 +3917,9 @@ NativeProcessLinux::DupDescriptor(const char *path, int fd, int flags)
}
void
NativeProcessLinux::StartMonitorThread(Error &error)
NativeProcessLinux::StartMonitorThread(const InitialOperation &initial_operation, Error &error)
{
m_monitor_up.reset(new Monitor(GetID(), this));
m_monitor_up.reset(new Monitor(initial_operation, this));
error = m_monitor_up->Initialize();
if (error.Fail()) {
m_monitor_up.reset();
@ -4051,27 +3929,8 @@ NativeProcessLinux::StartMonitorThread(Error &error)
void
NativeProcessLinux::StopMonitor()
{
m_monitor_up.reset();
StopCoordinatorThread ();
StopOpThread();
sem_destroy(&m_operation_pending);
sem_destroy(&m_operation_done);
// TODO: validate whether this still holds, fix up comment.
// Note: ProcessPOSIX passes the m_terminal_fd file descriptor to
// Process::SetSTDIOFileDescriptor, which in turn transfers ownership of
// the descriptor to a ConnectionFileDescriptor object. Consequently
// even though still has the file descriptor, we shouldn't close it here.
}
void
NativeProcessLinux::StopOpThread()
{
if (!m_operation_thread.IsJoinable())
return;
DoOperation(EXIT_OPERATION);
m_operation_thread.Join(nullptr);
m_monitor_up.reset();
}
Error

68
lldb/source/Plugins/Process/Linux/NativeProcessLinux.h
View File

@ -176,16 +176,6 @@ namespace process_linux {
ArchSpec m_arch;
std::unique_ptr<Monitor> m_monitor_up;
HostThread m_operation_thread;
// current operation which must be executed on the priviliged thread
void *m_operation;
Mutex m_operation_mutex;
// semaphores notified when Operation is ready to be processed and when
// the operation is complete.
sem_t m_operation_pending;
sem_t m_operation_done;
LazyBool m_supports_mem_region;
std::vector<MemoryRegionInfo> m_mem_region_cache;
@ -198,25 +188,13 @@ namespace process_linux {
// the relevan breakpoint
std::map<lldb::tid_t, lldb::addr_t> m_threads_stepping_with_breakpoint;
struct OperationArgs
{
OperationArgs(NativeProcessLinux *monitor);
~OperationArgs();
NativeProcessLinux *m_monitor; // The monitor performing the attach.
sem_t m_semaphore; // Posted to once operation complete.
Error m_error; // Set if process operation failed.
};
/// @class LauchArgs
///
/// @brief Simple structure to pass data to the thread responsible for
/// launching a child process.
struct LaunchArgs : OperationArgs
struct LaunchArgs
{
LaunchArgs(NativeProcessLinux *monitor,
Module *module,
LaunchArgs(Module *module,
char const **argv,
char const **envp,
const std::string &stdin_path,
@ -237,15 +215,7 @@ namespace process_linux {
const ProcessLaunchInfo &m_launch_info;
};
struct AttachArgs : OperationArgs
{
AttachArgs(NativeProcessLinux *monitor,
lldb::pid_t pid);
~AttachArgs();
lldb::pid_t m_pid; // pid of the process to be attached.
};
typedef std::function<::pid_t(Error &)> InitialOperation;
// ---------------------------------------------------------------------
// Private Instance Methods
@ -272,32 +242,17 @@ namespace process_linux {
AttachToInferior (lldb::pid_t pid, Error &error);
void
StartMonitorThread(Error &error);
StartMonitorThread(const InitialOperation &operation, Error &error);
void
StartLaunchOpThread(LaunchArgs *args, Error &error);
::pid_t
Launch(LaunchArgs *args, Error &error);
static void *
LaunchOpThread(void *arg);
static bool
Launch(LaunchArgs *args);
void
StartAttachOpThread(AttachArgs *args, Error &error);
static void *
AttachOpThread(void *args);
static bool
Attach(AttachArgs *args);
::pid_t
Attach(lldb::pid_t pid, Error &error);
static Error
SetDefaultPtraceOpts(const lldb::pid_t);
static void
ServeOperation(OperationArgs *args);
static bool
DupDescriptor(const char *path, int fd, int flags);
@ -336,13 +291,6 @@ namespace process_linux {
GetCrashReasonForSIGBUS(const siginfo_t *info);
#endif
void
DoOperation(void *op);
/// Stops the operation thread used to attach/launch a process.
void
StopOpThread();
Error
StartCoordinatorThread ();

1
lldb/test/functionalities/thread/concurrent_events/TestConcurrentEvents.py
View File

@ -70,7 +70,6 @@ class ConcurrentEventsTestCase(TestBase):
self.do_thread_actions(num_breakpoint_threads=1, num_signal_threads=1)
@dwarf_test
@expectedFailureLinux # this test fails 2/100 dosep runs
def test_delay_signal_break_dwarf(self):
"""Test (1-second delay) signal and a breakpoint in multiple threads."""
self.buildDwarf(dictionary=self.getBuildFlags())