win: Add implementation of system_snapshot for Windows

snapshot/win/system_snapshot_win.cc

Index: snapshot/win/system_snapshot_win.cc
diff --git a/snapshot/win/system_snapshot_win.cc b/snapshot/win/system_snapshot_win.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a6541be82e8e6293bbec81dc258670cfe44754ca
--- /dev/null
+++ b/snapshot/win/system_snapshot_win.cc
@@ -0,0 +1,269 @@
+// Copyright 2015 The Crashpad Authors. All rights reserved.
+//
+// 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 "snapshot/win/system_snapshot_win.h"
+
+#include <immintrin.h>
+#include <powrprof.h>
+#include <windows.h>
+
+#include <vector>
+
+#include "base/numerics/safe_conversions.h"
+#include "base/strings/stringprintf.h"
+#include "base/strings/utf_string_conversions.h"
+
+namespace crashpad {
+
+namespace internal {
+
+SystemSnapshotWin::SystemSnapshotWin()
+    : SystemSnapshot(),
+      os_version_full_(),
+      os_version_build_(),
+      process_reader_(nullptr),
+      os_version_major_(0),
+      os_version_minor_(0),
+      os_version_bugfix_(0),
+      os_server_(false),
+      initialized_() {
+}
+
+SystemSnapshotWin::~SystemSnapshotWin() {
+}
+
+void SystemSnapshotWin::Initialize(ProcessReaderWin* process_reader) {
+  INITIALIZATION_STATE_SET_INITIALIZING(initialized_);
+
+  process_reader_ = process_reader;
+
+  OSVERSIONINFOEX version_info = {sizeof(version_info)};
+  if (!GetVersionEx(reinterpret_cast<OSVERSIONINFO*>(&version_info))) {

[Mark Mentovai, 2015/02/20 18:58:52]

Looking at the docs for GetVersionEx(), I’m learning that its behavior has
changed for Windows 8.1 and later. Is there a way to reliably determine the OS
version number on these newer operating systems?

[scottmg, 2015/02/20 22:00:44]

GetVersionEx works as long as the manifest is set correctly (it may not yet be
in the crashpad test binaries).

We could use these tedious functions
https://msdn.microsoft.com/en-us/library/windows/desktop/dn424972(v=vs.85).aspx
but then wouldn't get a number for Win 10.

I also sort of prefer using this function, as it matches what Chromium does, on
the off-chance that there's some minor discrepancy that causes confusion.

+    PLOG(WARNING) << "GetVersionEx";
+  }
+  os_version_major_ = version_info.dwMajorVersion;
+  os_version_minor_ = version_info.dwMinorVersion;
+  os_version_bugfix_ = version_info.dwBuildNumber;
+  os_version_build_ =
+      base::StringPrintf("Service Pack %d", version_info.wServicePackMajor);

[Mark Mentovai, 2015/02/20 18:58:52]

If GetVersionEx() failed, you shouldn’t do this.

Everything from line 55 to 70 can be in an “else”.

Also, if both version_info.wServicePackMajor and version_info.wServicePackMinor
are 0, do you need a service pack string at all? I don’t think so.

[scottmg, 2015/02/20 22:00:45]

Done.

+  if (version_info.wServicePackMinor != 0) {
+    os_version_build_ +=
+        base::StringPrintf(".%d", version_info.wServicePackMinor);
+  }
+  os_server_ = version_info.wProductType != VER_NT_WORKSTATION;
+  // TODO(scottmg): Is there something more we can retrieve here?
+  os_version_full_ = base::StringPrintf("Windows %d.%d.%d %s",

[Mark Mentovai, 2015/02/20 18:58:52]

Should this be Windows NT instead of Windows? Avoid version number confusion…

Is there a way to get the OS to give us the name to use here?

If os_version_build_ might be empty, this shouldn’t end up with a trailing
space.

The %d should probably be %u, same on lines 59 and 62.

[scottmg, 2015/02/20 22:00:45]

Changed in Service Pack, but not here. They're printed from ints which are
converted to match OSVersion()s outputs.

+                                        os_version_major_,
+                                        os_version_minor_,
+                                        os_version_bugfix_,
+                                        os_version_build_.c_str());
+
+  INITIALIZATION_STATE_SET_VALID(initialized_);
+}
+
+CPUArchitecture SystemSnapshotWin::GetCPUArchitecture() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+
+  return process_reader_->Is64Bit() ? kCPUArchitectureX86_64
+                                    : kCPUArchitectureX86;
+}
+
+uint32_t SystemSnapshotWin::CPURevision() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+
+  // TODO(scottmg): How does this differ from CPUX86Signature below?

[Mark Mentovai, 2015/02/20 18:58:52]

CPURevision() is not CPU architecture-specific, but CPUX86Signature() is
x86-family-specific.

CPURevision() for x86-family CPUs returns interpreted family/model/stepping
values as 16/8/8 bits. The extended family ID and extended model ID are taken
into account.

CPUX86Signature() returns cpuid 1 eax in its raw form. The family, model,
stepping, extended family, and extended model numbers are encoded in that, but
more work needs to be done to make use of them. cpuid 1 eax also carries two
“processor type” bits and some reserved bits that are not preserved in
CPURevision(). Things that need the actual value of cpuid 1 eax from an
x86-family CPU use this instead of CPURevision().

In a minidump file, MINIDUMP_SYSTEM_INFO::ProcessorLevel (family) and
MINIDUMP_SYSTEM_INFO::ProcessorRevision (model and stepping) are set using
CPURevision(). These two fields are valid for all architectures, not just x86.
MINIDUMP_SYSTEM_INFO::Cpu.X86CpuInfo.VersionInformation is set to
CPUX86Signature() for 32-bit x86 only (not x86_64). This field isn’t present for
other CPUs.

The comments in our copy of dbghelp.h explain this as far as minidumps are
concerned, and system_snapshot.h explains it for the snapshot interface,
although I agree that the difference is subtle.

This was done with a new method for CPUX86Signature() in case the “processor
type” or other reserved bits become significant in the future. This design
ensures that they’re captured, since there’s a spot for all of cpuid 1 eax to be
carried without modification, instead of attempting to rebuild cpuid 1 eax from
the decoded family/model/stepping in CPURevision().

[scottmg, 2015/02/20 22:00:45]

Thanks for the explanation. Done.

+  CHECK(false) << "TODO: family << 16 | model << 8 | stepping";
+  return 0;
+}
+
+uint8_t SystemSnapshotWin::CPUCount() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+
+  SYSTEM_INFO system_info;
+  GetSystemInfo(&system_info);
+  return base::saturated_cast<uint8_t>(system_info.dwNumberOfProcessors);

[Mark Mentovai, 2015/02/20 18:58:52]

Log a warning if this saturates.

[scottmg, 2015/02/20 22:00:45]

Done.

+}
+
+std::string SystemSnapshotWin::CPUVendor() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+
+  int cpu_info[4];
+  __cpuid(cpu_info, 0);
+  char vendor[13] = {0};
+  *reinterpret_cast<int*>(vendor) = cpu_info[1];
+  *reinterpret_cast<int*>(vendor + 4) = cpu_info[3];
+  *reinterpret_cast<int*>(vendor + 8) = cpu_info[2];
+  return vendor;

[Mark Mentovai, 2015/02/20 18:58:52]

std::string(vendor, 12)

or make vendor be size 12 and do std::string(vendor, sizeof(vendor))

[scottmg, 2015/02/20 22:00:45]

Done.

+}
+
+// https://msdn.microsoft.com/en-us/library/windows/desktop/aa373184.aspx:
+// "Note that this structure definition was accidentally omitted from WinNT.h."

[Mark Mentovai, 2015/02/20 18:58:52]

Belongs in compat then?

[scottmg, 2015/02/20 22:00:45]

Done.

+struct PROCESSOR_POWER_INFORMATION {
+  ULONG Number;
+  ULONG MaxMhz;
+  ULONG CurrentMhz;
+  ULONG MhzLimit;
+  ULONG MaxIdleState;
+  ULONG CurrentIdleState;
+};
+
+void SystemSnapshotWin::CPUFrequency(uint64_t* current_hz,
+                                     uint64_t* max_hz) const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+
+  int num_cpus = CPUCount();
+  std::vector<PROCESSOR_POWER_INFORMATION> info(num_cpus);
+  if (CallNtPowerInformation(ProcessorInformation,
+                             nullptr,
+                             0,
+                             &info[0],
+                             sizeof(PROCESSOR_POWER_INFORMATION) * num_cpus) !=
+      0) {
+    *current_hz = 0;
+    *max_hz = 0;
+    return;
+  }
+  // TODO(scottmg): Return all? Average? Current?

[Mark Mentovai, 2015/02/20 18:58:52]

Good question. Max of current and max of max?

[scottmg, 2015/02/20 22:00:45]

Done.

+  const uint64_t kMhzToHz = 1000000;

[Mark Mentovai, 2015/02/20 18:58:52]

1E6

[scottmg, 2015/02/20 22:00:45]

Done.

+  *current_hz = info[0].CurrentMhz * kMhzToHz;
+  *max_hz = info[0].MaxMhz * kMhzToHz;
+}
+
+uint32_t SystemSnapshotWin::CPUX86Signature() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+
+  int cpu_info[4];
+  // We will never run on any processors that don't support at least function 1.
+  __cpuid(cpu_info, 1);
+  return cpu_info[0];
+}
+
+uint64_t SystemSnapshotWin::CPUX86Features() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+
+  int cpu_info[4];
+  // We will never run on any processors that don't support at least function 1.
+  __cpuid(cpu_info, 1);
+  return (static_cast<uint64_t>(cpu_info[2]) << 32) |
+         static_cast<uint64_t>(cpu_info[3]);
+}
+
+uint64_t SystemSnapshotWin::CPUX86ExtendedFeatures() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+
+  int cpu_info[4];
+  // We will never run on any processors that don't support at least extended
+  // function 1.
+  __cpuid(cpu_info, 0x80000001);
+  return (static_cast<uint64_t>(cpu_info[2]) << 32) |
+         static_cast<uint64_t>(cpu_info[3]);
+  return (static_cast<uint64_t>(cpu_info[2]) << 32) |

[Mark Mentovai, 2015/02/20 18:58:52]

You already returned this.

[scottmg, 2015/02/20 22:00:45]

Hm, maybe I should look into enabling the unreachable code warning. Done.

+         static_cast<uint64_t>(cpu_info[3]);
+}
+
+uint32_t SystemSnapshotWin::CPUX86Leaf7Features() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+
+  int cpu_info[4];
+
+  // Make sure leaf 7 can be called.
+  __cpuid(cpu_info, 0);
+  if (cpu_info[0] < 7)
+    return 0;
+
+  __cpuidex(cpu_info, 7, 0);
+  return cpu_info[1];
+}
+
+bool SystemSnapshotWin::CPUX86SupportsDAZ() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+
+  // The correct way to check for denormals-as-zeros (DAZ) support is to examine
+  // mxcsr mask, which can be done with fxsave. See Intel Software Developer's
+  // Manual, Volume 1: Basic Architecture (253665-051), 11.6.3 "Checking for the
+  // DAZ Flag in the MXCSR Register". Note that since this function tests for
+  // DAZ support in the CPU, it checks the mxcsr mask. Testing mxcsr would
+  // indicate whether DAZ is actually enabled, which is a per-thread context
+  // concern.
+
+  // Test for fxsave support.
+  uint64_t features = CPUX86Features();
+  if (!(features & (UINT64_C(1) << 24))) {
+    return false;
+  }
+
+  // Call fxsave.
+  __declspec(align(16)) uint32_t extended_registers[128];
+  _fxsave(&extended_registers);
+  uint32_t mxcsr_mask = extended_registers[7];
+
+  // Test the DAZ bit.
+  return mxcsr_mask & (1 << 6);
+}
+
+SystemSnapshot::OperatingSystem SystemSnapshotWin::GetOperatingSystem() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+  return kOperatingSystemWindows;
+}
+
+bool SystemSnapshotWin::OSServer() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+  return os_server_;
+}
+
+void SystemSnapshotWin::OSVersion(int* major,
+                                  int* minor,
+                                  int* bugfix,
+                                  std::string* build) const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+  *major = os_version_major_;
+  *minor = os_version_minor_;
+  *bugfix = os_version_bugfix_;
+  build->assign(os_version_build_);
+}
+
+std::string SystemSnapshotWin::OSVersionFull() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+  return os_version_full_;
+}
+
+std::string SystemSnapshotWin::MachineDescription() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+  // TODO(scottmg): Not sure if there's anything sensible to put here.
+  return "";

[Mark Mentovai, 2015/02/20 18:58:52]

std::string() (I was reminded of this during the readability review). I don’t
know if there’s anything sensible you can get on Windows either, since the
hardware’s a lot more diverse.

[scottmg, 2015/02/20 22:00:45]

Done.

+}
+
+bool SystemSnapshotWin::NXEnabled() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+  return IsProcessorFeaturePresent(PF_NX_ENABLED);
+}
+
+void SystemSnapshotWin::TimeZone(DaylightSavingTimeStatus* dst_status,
+                                 int* standard_offset_seconds,
+                                 int* daylight_offset_seconds,
+                                 std::string* standard_name,
+                                 std::string* daylight_name) const {
+  TIME_ZONE_INFORMATION time_zone_information;

[Mark Mentovai, 2015/02/20 18:58:52]

Comment that this returns the current time zone status in dst_status, and not
the status at the time of the snapshot. This is unlike the Mac implementation.

[scottmg, 2015/02/20 22:00:45]

Done.

+  *dst_status = static_cast<DaylightSavingTimeStatus>(
+      GetTimeZoneInformation(&time_zone_information));
+  *standard_offset_seconds =
+      (time_zone_information.Bias + time_zone_information.StandardBias) * -60;
+  *daylight_offset_seconds =
+      (time_zone_information.Bias + time_zone_information.DaylightBias) * -60;
+  *standard_name = base::UTF16ToUTF8(time_zone_information.StandardName);
+  *daylight_name = base::UTF16ToUTF8(time_zone_information.DaylightName);
+}
+
+}  // namespace internal
+}  // namespace crashpad