Add ExceptionSnapshotMac

snapshot/exception_snapshot_mac.cc

Index: snapshot/exception_snapshot_mac.cc
diff --git a/snapshot/exception_snapshot_mac.cc b/snapshot/exception_snapshot_mac.cc
new file mode 100644
index 0000000000000000000000000000000000000000..df2fd1a169c7e33cc0bc0546590d678ebe919459
--- /dev/null
+++ b/snapshot/exception_snapshot_mac.cc
@@ -0,0 +1,179 @@
+// Copyright 2014 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/exception_snapshot_mac.h"
+
+#include "base/logging.h"
+#include "snapshot/cpu_context_mac.h"
+#include "util/mac/process_reader.h"
+
+namespace crashpad {
+namespace internal {
+
+ExceptionSnapshotMac::ExceptionSnapshotMac()
+    : ExceptionSnapshot(),
+      context_union_(),
+      context_(),
+      codes_(),
+      thread_id_(0),
+      exception_address_(0),
+      exception_(0),
+      exception_code_0_(0),
+      initialized_() {
+}
+
+ExceptionSnapshotMac::~ExceptionSnapshotMac() {
+}
+
+bool ExceptionSnapshotMac::Initialize(ProcessReader* process_reader,
+                                      thread_t exception_thread,
+                                      exception_type_t exception,
+                                      const mach_exception_data_type_t* code,
+                                      mach_msg_type_number_t code_count,
+                                      thread_state_flavor_t flavor,
+                                      const natural_t* state,
+                                      mach_msg_type_number_t state_count) {
+  INITIALIZATION_STATE_SET_INITIALIZING(initialized_);
+
+  codes_.push_back(exception);
+  for (mach_msg_type_number_t code_index = 0;
+       code_index < code_count;
+       ++code_index) {
+    codes_.push_back(code[code_index]);
+  }
+
+  exception_ = exception;
+  exception_code_0_ = code[0];
+
+  if (exception == EXC_CRASH) {
+    // Recover the original exception and the original code[0] from code[0]. See
+    // 10.9.5 xnu-2422.115.4/bsd/kern/kern_exit.c proc_prepareexit().
+    //
+    // This is only done if the EXC_CRASH exception originated from a previous
+    // exception. This is not the case for certain software-triggered
+    // terminations, such as exiting on a signal that causes termination. This
+    // happens by default for SIGABRT, for example, so abort() calls will
+    // ordinarily lead to EXC_CRASH showing up in Exception().
+    //
+    // Note: the signal number is stored at (code[0] >> 24) & 0xff.
+    exception_type_t original_exception = (code[0] >> 20) & 0xf;

[Robert Sesek, 2014/10/13 21:04:54]

This is ExcCrashRecoverOriginalException() right?

+    if (original_exception > 0) {
+      exception_ = original_exception;
+      exception_code_0_ = code[0] & 0xfffff;
+    }
+  }
+
+  const std::vector<ProcessReader::Thread>& threads = process_reader->Threads();
+  const ProcessReader::Thread* thread = NULL;
+  for (std::vector<ProcessReader::Thread>::const_iterator thread_iterator =

[Robert Sesek, 2014/10/13 21:04:54]

C++11 loop ?

+           threads.begin();
+       thread_iterator != threads.end();
+       ++thread_iterator) {
+    if (exception_thread == thread_iterator->port) {
+      thread = &*thread_iterator;
+      break;
+    }
+  }
+
+  if (!thread) {
+    LOG(WARNING) << "exception_thread not found in task";
+    return false;
+  }
+
+  thread_id_ = thread->id;
+
+  // Normally, the exception address is present in code[1] for EXC_BAD_ACCESS
+  // exceptions, but not for other types of exceptions.
+  bool code_1_is_exception_address = exception_ == EXC_BAD_ACCESS;
+
+#if defined(ARCH_CPU_X86_FAMILY)
+  if (process_reader->Is64Bit()) {
+    context_.architecture = kCPUArchitectureX86_64;
+    context_.x86_64 = &context_union_.x86_64;
+    InitializeCPUContextX86_64(context_.x86_64,
+                               flavor,
+                               state,
+                               state_count,
+                               &thread->thread_context.t64,
+                               &thread->float_context.f64,
+                               &thread->debug_context.d64);
+  } else {
+    context_.architecture = kCPUArchitectureX86;
+    context_.x86 = &context_union_.x86;
+    InitializeCPUContextX86(context_.x86,
+                            flavor,
+                            state,
+                            state_count,
+                            &thread->thread_context.t32,
+                            &thread->float_context.f32,
+                            &thread->debug_context.d32);
+  }
+
+  // For x86 and x86_64 EXC_BAD_ACCESS exceptions, some code[0] values indicate
+  // that code[1] does not (or may not) carry the exception address:
+  // EXC_I386_GPFLT (10.9.5 xnu-2422.115.4/osfmk/i386/trap.c user_trap() for
+  // T_GENERAL_PROTECTION) and the oddball (VM_PROT_READ | VM_PROT_EXECUTE)
+  // which collides with EXC_I386_BOUNDFLT (10.9.5
+  // xnu-2422.115.4/osfmk/i386/fpu.c fpextovrflt()). Other EXC_BAD_ACCESS
+  // exceptions come through 10.9.5 xnu-2422.115.4/osfmk/i386/trap.c
+  // user_page_fault_continue() and do contain the exception address in code[1].
+  if (exception_ == EXC_BAD_ACCESS &&
+      (exception_code_0_ == EXC_I386_GPFLT ||
+       exception_code_0_ == (VM_PROT_READ | VM_PROT_EXECUTE))) {
+    code_1_is_exception_address = false;
+  }
+#endif
+
+  if (code_1_is_exception_address) {
+    exception_address_ = code[1];
+  } else {
+    exception_address_ = context_.InstructionPointer();
+  }
+
+  INITIALIZATION_STATE_SET_VALID(initialized_);
+  return true;
+}
+
+const CPUContext* ExceptionSnapshotMac::Context() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+  return &context_;
+}
+
+uint64_t ExceptionSnapshotMac::ThreadID() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+  return thread_id_;
+}
+
+uint32_t ExceptionSnapshotMac::Exception() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+  return exception_;
+}
+
+uint32_t ExceptionSnapshotMac::ExceptionInfo() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+  return exception_code_0_;
+}
+
+uint64_t ExceptionSnapshotMac::ExceptionAddress() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+  return exception_address_;
+}
+
+const std::vector<uint64_t>& ExceptionSnapshotMac::Codes() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+  return codes_;
+}
+
+}  // namespace internal
+}  // namespace crashpad