win: Add thread snapshot and memory snapshot for stacks

snapshot/win/process_reader_win.cc

Index: snapshot/win/process_reader_win.cc
diff --git a/snapshot/win/process_reader_win.cc b/snapshot/win/process_reader_win.cc
index 84e176b8739dcdee035210dcdeb6850d44d12db6..a8774b01d30af366c80ca61d80dc911a4acf3c8c 100644
--- a/snapshot/win/process_reader_win.cc
+++ b/snapshot/win/process_reader_win.cc
@@ -14,15 +14,216 @@
 
 #include "snapshot/win/process_reader_win.h"
 
+#include <winternl.h>
+
+#include "base/memory/scoped_ptr.h"
 #include "base/numerics/safe_conversions.h"
+#include "util/win/process_structs.h"
+#include "util/win/scoped_handle.h"
 #include "util/win/time.h"
 
 namespace crashpad {
 
+namespace {
+
+NTSTATUS NtQuerySystemInformation(
+    SYSTEM_INFORMATION_CLASS system_information_class,
+    PVOID system_information,
+    ULONG system_information_length,
+    PULONG return_length) {
+  static decltype(::NtQuerySystemInformation)* nt_query_system_information =
+      reinterpret_cast<decltype(::NtQuerySystemInformation)*>(GetProcAddress(
+          LoadLibrary(L"ntdll.dll"), "NtQuerySystemInformation"));
+  DCHECK(nt_query_system_information);
+  return nt_query_system_information(system_information_class,
+                                     system_information,
+                                     system_information_length,
+                                     return_length);
+}
+
+// The 4th argument is CLIENT_ID*, but as we can't typedef that, we simply cast
+// to void* here.
+typedef NTSTATUS(WINAPI* NtOpenThreadFunction)(
+    PHANDLE ThreadHandle,
+    ACCESS_MASK DesiredAccess,
+    POBJECT_ATTRIBUTES ObjectAttributes,
+    const void* ClientId);
+
+template <class Traits>
+NTSTATUS NtOpenThread(PHANDLE thread_handle,
+                      ACCESS_MASK desired_access,
+                      POBJECT_ATTRIBUTES object_attributes,
+                      const process_types::CLIENT_ID<Traits>* client_id) {
+  static NtOpenThreadFunction nt_open_thread =
+      reinterpret_cast<NtOpenThreadFunction>(
+          GetProcAddress(LoadLibrary(L"ntdll.dll"), "NtOpenThread"));
+  DCHECK(nt_open_thread);
+  return nt_open_thread(thread_handle,
+                        desired_access,
+                        object_attributes,
+                        static_cast<const void*>(client_id));
+}
+
+NTSTATUS NtQueryInformationThread(HANDLE thread_handle,
+                                  THREADINFOCLASS thread_information_class,
+                                  PVOID thread_information,
+                                  ULONG thread_information_length,
+                                  PULONG return_length) {
+  static decltype(::NtQueryInformationThread)* nt_query_information_thread =
+      reinterpret_cast<decltype(::NtQueryInformationThread)*>(GetProcAddress(
+          LoadLibrary(L"ntdll.dll"), "NtQueryInformationThread"));
+  DCHECK(nt_query_information_thread);
+  return nt_query_information_thread(thread_handle,
+                                     thread_information_class,
+                                     thread_information,
+                                     thread_information_length,
+                                     return_length);
+}
+
+// Copied from ntstatus.h because um/winnt.h conflicts with general inclusion of
+// ntstatus.h.
+#define STATUS_BUFFER_TOO_SMALL ((NTSTATUS)0xC0000023L)
+#define STATUS_INFO_LENGTH_MISMATCH ((NTSTATUS)0xC0000004L)
+
+// Gets a pointer to the process information structure after a given one, or
+// null when iteration is complete, assuming they've been retrieved in a block
+// via NtQuerySystemInformation().
+template <class Traits>
+process_types::SYSTEM_PROCESS_INFORMATION<Traits>* NextProcess(
+    process_types::SYSTEM_PROCESS_INFORMATION<Traits>* process) {
+  ULONG offset = process->NextEntryOffset;
+  if (offset == 0)
+    return nullptr;
+  return reinterpret_cast<process_types::SYSTEM_PROCESS_INFORMATION<Traits>*>(
+      reinterpret_cast<uint8_t*>(process) + offset);
+}
+
+//! \brief Retrieves the SYSTEM_PROCESS_INFORMATION for a given process.
+//!
+//! The returned pointer points into the memory block stored by \a buffer.
+//! Ownership of \a buffer is transferred to the caller.
+//!
+//! \return Pointer to the process' data, or nullptr if it was not found or on
+//!     error. On error, a message will be logged.
+template <class Traits>
+process_types::SYSTEM_PROCESS_INFORMATION<Traits>* GetProcessInformation(
+    HANDLE process_handle,
+    scoped_ptr<uint8_t[]>* buffer) {
+  ULONG buffer_size = 16384;
+  buffer->reset(new uint8_t[buffer_size]);
+  NTSTATUS status;
+  // This must be in retry loop, as we're racing with process creation on the
+  // system to find a buffer large enough to hold all process information.
+  for (int tries = 0; tries < 20; ++tries) {
+    const int kSystemExtendedProcessInformation = 57;
+    status = crashpad::NtQuerySystemInformation(
+        static_cast<SYSTEM_INFORMATION_CLASS>(
+            kSystemExtendedProcessInformation),
+        reinterpret_cast<void*>(buffer->get()),
+        buffer_size,
+        &buffer_size);
+    if (status == STATUS_BUFFER_TOO_SMALL ||
+        status == STATUS_INFO_LENGTH_MISMATCH) {
+      // Add a little extra to try to avoid an additional loop iteration. We're
+      // racing with system-wide process creation between here and the next call
+      // to NtQuerySystemInformation().
+      buffer_size += 4096;
+      buffer->reset(new uint8_t[buffer_size]);
+    } else {
+      break;
+    }
+  }
+
+  if (!NT_SUCCESS(status)) {
+    LOG(ERROR) << "NtQuerySystemInformation failed: " << std::hex << status;
+    return nullptr;
+  }
+
+  process_types::SYSTEM_PROCESS_INFORMATION<Traits>* process =
+      reinterpret_cast<process_types::SYSTEM_PROCESS_INFORMATION<Traits>*>(
+          buffer->get());
+  DWORD process_id = GetProcessId(process_handle);
+  do {
+    if (process->UniqueProcessId == process_id)
+      return process;
+  } while (process = NextProcess(process));
+
+  LOG(ERROR) << "process " << process_id << " not found";
+  return nullptr;
+}
+
+template <class Traits>
+uint32_t GetThreadSuspendCount(
+    const process_types::SYSTEM_EXTENDED_THREAD_INFORMATION<Traits>&
+        thread_info) {
+  // Wait reason values are from KWAIT_REASON in wdm.h. We don't need all of
+  // them, so just declare the one we need.
+  const ULONG kWaitReasonSuspended = 5;
+
+  // Kernel mode enumerations for thread state come from
+  // http://www.nirsoft.net/kernel_struct/vista/KTHREAD_STATE.html and
+  // https://msdn.microsoft.com/en-us/library/system.diagnostics.threadstate(v=vs.110).aspx
+  const ULONG kThreadStateWaiting = 5;
+  const ULONG kThreadStateGateWait = 8;
+
+  bool suspended = (thread_info.ThreadState == kThreadStateWaiting ||
+                    thread_info.ThreadState == kThreadStateGateWait) &&
+                   thread_info.WaitReason == kWaitReasonSuspended;
+  if (!suspended)
+    return 0;
+
+  HANDLE thread_handle;
+  ACCESS_MASK query_access = THREAD_QUERY_LIMITED_INFORMATION;
+  OBJECT_ATTRIBUTES object_attributes;
+  InitializeObjectAttributes(&object_attributes, nullptr, 0, nullptr, nullptr);
+  NTSTATUS status = crashpad::NtOpenThread(
+      &thread_handle, query_access, &object_attributes, &thread_info.ClientId);
+  if (!NT_SUCCESS(status)) {
+    LOG(WARNING) << "couldn't open thread to retrieve suspend count";
+    // Fall back to something semi-reasonable. We know we're suspended at this
+    // point, so just return 1.
+    return 1;
+  }
+
+  // Take ownership of this handle so we close on exit. NtClose and CloseHandle
+  // are identical.
+  ScopedKernelHANDLE handle(thread_handle);
+
+  // From ntddk.h. winternl.h defines THREADINFOCLASS, but only one value.
+  const int kThreadSuspendCount = 35;
+  ULONG suspend_count;
+  status = crashpad::NtQueryInformationThread(
+      handle.get(),
+      static_cast<THREADINFOCLASS>(kThreadSuspendCount),
+      &suspend_count,
+      sizeof(suspend_count),
+      nullptr);
+  if (!NT_SUCCESS(status)) {
+    LOG(WARNING) << "NtQueryInformationThread failed" << std::hex << status;
+    return 1;
+  }
+
+  return suspend_count;
+}
+
+}  // namespace
+
+ProcessReaderWin::Thread::Thread()
+    : id(0),
+      teb(0),
+      stack_region_address(0),
+      stack_region_size(0),
+      suspend_count(0),
+      priority_class(0),
+      priority(0) {
+}
+
 ProcessReaderWin::ProcessReaderWin()
     : process_(INVALID_HANDLE_VALUE),
       process_info_(),
+      threads_(),
       modules_(),
+      initialized_threads_(false),
       initialized_() {
 }
 
@@ -77,6 +278,61 @@ bool ProcessReaderWin::CPUTimes(timeval* user_time,
   return true;
 }
 
+const std::vector<ProcessReaderWin::Thread>& ProcessReaderWin::Threads() {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+
+  if (initialized_threads_)
+    return threads_;
+
+  initialized_threads_ = true;
+
+  DCHECK(threads_.empty());
+
+#if ARCH_CPU_32_BITS
+  using SizeTraits = process_types::internal::Traits32;
+#else
+  using SizeTraits = process_types::internal::Traits64;
+#endif
+  scoped_ptr<uint8_t[]> buffer;
+  process_types::SYSTEM_PROCESS_INFORMATION<SizeTraits>* process_information =
+      GetProcessInformation<SizeTraits>(process_, &buffer);
+  if (!process_information)
+    return threads_;
+
+  for (unsigned long i = 0; i < process_information->NumberOfThreads; ++i) {
+    const process_types::SYSTEM_EXTENDED_THREAD_INFORMATION<SizeTraits>&
+        thread_info = process_information->Threads[i];
+    Thread thread;
+    thread.id = thread_info.ClientId.UniqueThread;
+    thread.suspend_count = GetThreadSuspendCount(thread_info);
+
+    // TODO(scottmg): I believe we could reverse engineer the PriorityClass from
+    // the Priority, BasePriority, and
+    // https://msdn.microsoft.com/en-us/library/windows/desktop/ms685100 .
+    // MinidumpThreadWriter doesn't handle it yet in any case, so investigate
+    // both of those at the same time if it's useful.
+    thread.priority_class = NORMAL_PRIORITY_CLASS;
+
+    thread.priority = thread_info.Priority;
+    thread.teb = thread_info.TebBase;
+
+    // While there are semi-documented fields in the thread structure called
+    // StackBase and StackLimit, they don't appear to be correct in practice (or
+    // at least, I don't know how to interpret them). Instead, read the TIB
+    // (Thread Information Block) which is the first element of the TEB, and use
+    // its stack fields.
+    process_types::NT_TIB<SizeTraits> tib;
+    if (ReadMemory(thread_info.TebBase, sizeof(tib), &tib)) {
+      thread.stack_region_address = tib.StackBase;
+      // Note, "backwards" because of direction of stack growth.
+      thread.stack_region_size = tib.StackBase - tib.StackLimit;
+    }
+    threads_.push_back(thread);
+  }
+
+  return threads_;
+}
+
 const std::vector<ProcessInfo::Module>& ProcessReaderWin::Modules() {
   INITIALIZATION_STATE_DCHECK_VALID(initialized_);