win: Capture some memory pointed at by context

snapshot/win/capture_context_memory.cc

Index: snapshot/win/capture_context_memory.cc
diff --git a/snapshot/win/capture_context_memory.cc b/snapshot/win/capture_context_memory.cc
new file mode 100644
index 0000000000000000000000000000000000000000..1c69cc36674c159369045e790a9e58d4f05bf49a
--- /dev/null
+++ b/snapshot/win/capture_context_memory.cc
@@ -0,0 +1,78 @@
+// 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/capture_context_memory.h"
+
+#include "snapshot/win/memory_snapshot_win.h"
+#include "snapshot/win/process_reader_win.h"
+
+namespace crashpad {
+namespace internal {
+
+namespace {
+
+void MaybeCaptureMemoryAround(ProcessReaderWin* process_reader,
+                              WinVMAddress address,
+                              PointerVector<MemorySnapshotWin>* into) {
+  if (address > 0x10000) {
+    const WinVMSize kRegisterByteOffset = 32;
+    const WinVMAddress target = address - kRegisterByteOffset;
+    const WinVMSize size = 128;
+    if (process_reader->GetProcessInfo().LoggingRangeIsFullyReadable(

[Mark Mentovai, 2016/01/08 19:20:52]

If the address is readable at all, we should do as much of the grab around it as
possible, even if the full 128-byte window isn’t grabbable.

[scottmg, 2016/01/08 19:52:02]

Done.

+            CheckedRange<WinVMAddress, WinVMSize>(target, size))) {
+      internal::MemorySnapshotWin* snapshot = new internal::MemorySnapshotWin();
+      snapshot->Initialize(process_reader, target, size);
+      into->push_back(snapshot);
+    }
+  }
+}
+
+}  // namespace
+
+void CaptureMemoryPointedToByContext(const CPUContext& context,
+                                     ProcessReaderWin* process_reader,
+                                     PointerVector<MemorySnapshotWin>* into) {
+#if defined(ARCH_CPU_X86_64)
+  if (context.architecture == kCPUArchitectureX86_64) {
+    MaybeCaptureMemoryAround(process_reader, context.x86_64->rax, into);
+    MaybeCaptureMemoryAround(process_reader, context.x86_64->rbx, into);
+    MaybeCaptureMemoryAround(process_reader, context.x86_64->rcx, into);
+    MaybeCaptureMemoryAround(process_reader, context.x86_64->rdx, into);
+    MaybeCaptureMemoryAround(process_reader, context.x86_64->rdi, into);
+    MaybeCaptureMemoryAround(process_reader, context.x86_64->rsi, into);

[Mark Mentovai, 2016/01/08 19:20:52]

If bp doesn’t point to the thread’s stack, you should grab it too.

[scottmg, 2016/01/08 19:52:02]

Done.

+    MaybeCaptureMemoryAround(process_reader, context.x86_64->r8, into);
+    MaybeCaptureMemoryAround(process_reader, context.x86_64->r9, into);
+    MaybeCaptureMemoryAround(process_reader, context.x86_64->r10, into);
+    MaybeCaptureMemoryAround(process_reader, context.x86_64->r11, into);
+    MaybeCaptureMemoryAround(process_reader, context.x86_64->r12, into);
+    MaybeCaptureMemoryAround(process_reader, context.x86_64->r13, into);
+    MaybeCaptureMemoryAround(process_reader, context.x86_64->r14, into);
+    MaybeCaptureMemoryAround(process_reader, context.x86_64->r15, into);
+    MaybeCaptureMemoryAround(process_reader, context.x86_64->rip, into);
+  } else {
+#endif
+    MaybeCaptureMemoryAround(process_reader, context.x86->eax, into);
+    MaybeCaptureMemoryAround(process_reader, context.x86->ebx, into);
+    MaybeCaptureMemoryAround(process_reader, context.x86->ecx, into);
+    MaybeCaptureMemoryAround(process_reader, context.x86->edx, into);
+    MaybeCaptureMemoryAround(process_reader, context.x86->edi, into);
+    MaybeCaptureMemoryAround(process_reader, context.x86->esi, into);
+    MaybeCaptureMemoryAround(process_reader, context.x86->eip, into);
+#if defined(ARCH_CPU_X86_64)
+  }
+#endif
+}
+
+}  // namespace internal
+}  // namespace crashpad