Add crashpad_info, MachOImageAnnotationsReader, and its test.

TEST=snapshot_test MachOImageAnnotationsReader.*
R=rsesek@chromium.org

Review URL: https://codereview.chromium.org/651283003

client/client.gyp

@@ -26,6 +26,8 @@
       'sources': [
         'capture_context_mac.h',
         'capture_context_mac.S',
+        'crashpad_info.cc',
+        'crashpad_info.h',
         'simple_string_dictionary.cc',
         'simple_string_dictionary.h',
         'simulate_crash.h',

client/crashpad_info.cc

@@ -0,0 +1,76 @@
+// 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 "client/crashpad_info.h"
+
+#include <mach-o/loader.h>
+
+#if CXX_LIBRARY_VERSION >= 2011
+#include <type_traits>
+#endif
+
+namespace {
+
+static const uint32_t kCrashpadInfoVersion = 1;
+
+}  // namespace
+
+namespace crashpad {
+
+#if CXX_LIBRARY_VERSION >= 2011
+// In C++11, check that CrashpadInfo has standard layout, which is what is
+// actually important.
+static_assert(std::is_standard_layout<CrashpadInfo>::value,
+              "CrashpadInfo must be standard layout");
+#else
+// In C++98 (ISO 14882), section 9.5.1 says that a union cannot have a member
+// with a non-trivial ctor, copy ctor, dtor, or assignment operator. Use this
+// property to ensure that CrashpadInfo remains POD. This doesn’t work for C++11
+// because the requirements for unions have been relaxed.
+union Compile_Assert {
+  CrashpadInfo Compile_Assert__CrashpadInfo_must_be_pod;
+};
+#endif
+
+// Put the structure in __DATA,__crashpad_info where it can be easily found
+// without having to consult the symbol table. The “used” attribute prevents it
+// from being dead-stripped. This isn’t placed in an unnamed namespace:
+// hopefully, this will catch attempts to place multiple copies of this
+// structure into the same module. If that’s attempted, and the name of the
+// symbol is the same in each translation unit, it will result in a linker
+// error, which is better than having multiple structures show up.
+//
+// This may result in a static module initializer in debug-mode builds, but
+// because it’s POD, no code should need to run to initialize this under
+// release-mode optimization.
+__attribute__((section(SEG_DATA ",__crashpad_info"),
+               used,
+               visibility("hidden"))) CrashpadInfo g_crashpad_info;
+
+// static
+CrashpadInfo* CrashpadInfo::GetCrashpadInfo() {
+  return &g_crashpad_info;
+}
+
+CrashpadInfo::CrashpadInfo()
+    : signature_(kSignature),
+      size_(sizeof(*this)),
+      version_(kCrashpadInfoVersion),
+      padding_0_(0),
+      simple_annotations_(nullptr) {
+}
+
+const uint32_t CrashpadInfo::kSignature;
+
+}  // namespace crashpad

client/crashpad_info.h

@@ -0,0 +1,66 @@
+// 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.
+
+#ifndef CRASHPAD_CLIENT_CRASHPAD_INFO_H_
+#define CRASHPAD_CLIENT_CRASHPAD_INFO_H_
+
+#include "base/basictypes.h"
+
+#include <stdint.h>
+
+#include "client/simple_string_dictionary.h"
+
+namespace crashpad {
+
+//! \brief A structure that can be used by a Crashpad-enabled program to
+//!     provide information to the Crashpad crash handler.
+//!
+//! It is possible for one CrashpadInfo structure to appear in each loaded code
+//! module in a process, but from the perspective of the user of the client
+//! interface, there is only one global CrashpadInfo structure, located in the
+//! module that contains the client interface code.
+struct CrashpadInfo {
+ public:
+  //! \brief Returns the global CrashpadInfo structure.
+  static CrashpadInfo* GetCrashpadInfo();
+
+  CrashpadInfo();
+
+  void set_simple_annotations(SimpleStringDictionary* simple_annotations) {
+    simple_annotations_ = simple_annotations;
+  }
+
+  static const uint32_t kSignature = 'CPad';
+
+ private:
+  // The compiler won’t necessarily see anyone using these fields, but it
+  // shouldn’t warn about that. These fields aren’t intended for use by the
+  // process they’re found in, they’re supposed to be read by the crash
+  // reporting process.
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wunused-private-field"
+  // Fields present in version 1:
+  uint32_t signature_;  // kSignature
+  uint32_t size_;  // The size of the entire CrashpadInfo structure.
+  uint32_t version_;  // kVersion
+  uint32_t padding_0_;
+  SimpleStringDictionary* simple_annotations_;  // weak
+#pragma clang diagnostic pop
+
+  DISALLOW_COPY_AND_ASSIGN(CrashpadInfo);
+};
+
+}  // namespace crashpad
+
+#endif  // CRASHPAD_CLIENT_CRASHPAD_INFO_H_

snapshot/mac/mach_o_image_annotations_reader.cc

@@ -0,0 +1,198 @@
+// 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/mac/mach_o_image_annotations_reader.h"
+
+#include <mach-o/loader.h>
+#include <mach/mach.h>
+
+#include "base/logging.h"
+#include "client/crashpad_info.h"
+#include "client/simple_string_dictionary.h"
+#include "snapshot/mac/mach_o_image_reader.h"
+#include "snapshot/mac/process_reader.h"
+#include "snapshot/mac/process_types.h"
+#include "util/mach/task_memory.h"
+#include "util/stdlib/strnlen.h"
+
+namespace crashpad {
+
+MachOImageAnnotationsReader::MachOImageAnnotationsReader(
+    ProcessReader* process_reader,
+    const MachOImageReader* image_reader,
+    const std::string& name)
+    : name_(name),
+      process_reader_(process_reader),
+      image_reader_(image_reader) {
+}
+
+std::vector<std::string> MachOImageAnnotationsReader::Vector() const {
+  std::vector<std::string> vector_annotations;
+
+  ReadCrashReporterClientAnnotations(&vector_annotations);
+  ReadDyldErrorStringAnnotation(&vector_annotations);
+
+  return vector_annotations;
+}
+
+std::map<std::string, std::string> MachOImageAnnotationsReader::SimpleMap()
+    const {
+  std::map<std::string, std::string> simple_map_annotations;
+
+  ReadCrashpadSimpleAnnotations(&simple_map_annotations);
+
+  return simple_map_annotations;
+}
+
+void MachOImageAnnotationsReader::ReadCrashReporterClientAnnotations(
+    std::vector<std::string>* vector_annotations) const {
+  mach_vm_address_t crash_info_address;
+  const process_types::section* crash_info_section =
+      image_reader_->GetSectionByName(
+          SEG_DATA, "__crash_info", &crash_info_address);
+  if (!crash_info_section) {
+    return;
+  }
+
+  process_types::crashreporter_annotations_t crash_info;
+  if (crash_info_section->size < crash_info.ExpectedSize(process_reader_)) {
+    LOG(WARNING) << "small crash info section size " << crash_info_section->size
+                 << " in " << name_;
+    return;
+  }
+
+  if (!crash_info.Read(process_reader_, crash_info_address)) {
+    LOG(WARNING) << "could not read crash info from " << name_;
+    return;
+  }
+
+  if (crash_info.version != 4) {
+    LOG(WARNING) << "unexpected crash info version " << crash_info.version
+                 << " in " << name_;
+    return;
+  }
+
+  // This number was totally made up out of nowhere, but it seems prudent to
+  // enforce some limit.
+  const size_t kMaxMessageSize = 1024;
+  if (crash_info.message) {
+    std::string message;
+    if (process_reader_->Memory()->
+            ReadCStringSizeLimited(
+                crash_info.message, kMaxMessageSize, &message)) {
+      vector_annotations->push_back(message);
+    } else {
+      LOG(WARNING) << "could not read crash message in " << name_;
+    }
+  }
+
+  if (crash_info.message2) {
+    std::string message;
+    if (process_reader_->Memory()->
+            ReadCStringSizeLimited(
+                crash_info.message2, kMaxMessageSize, &message)) {
+      vector_annotations->push_back(message);
+    } else {
+      LOG(WARNING) << "could not read crash message 2 in " << name_;
+    }
+  }
+}
+
+void MachOImageAnnotationsReader::ReadDyldErrorStringAnnotation(
+    std::vector<std::string>* vector_annotations) const {
+  // dyld stores its error string at the external symbol for |const char
+  // error_string[1024]|. See 10.9.5 dyld-239.4/src/dyld.cpp error_string.
+  if (image_reader_->FileType() != MH_DYLINKER) {
+    return;
+  }
+
+  mach_vm_address_t error_string_address;
+  if (!image_reader_->LookUpExternalDefinedSymbol("_error_string",
+                                                  &error_string_address)) {
+    return;
+  }
+
+  std::string message;
+  // 1024 here is distinct from kMaxMessageSize above, because it refers to a
+  // precisely-sized buffer inside dyld.
+  if (process_reader_->Memory()->
+          ReadCStringSizeLimited(error_string_address, 1024, &message)) {
+    if (!message.empty()) {
+      vector_annotations->push_back(message);
+    }
+  } else {
+    LOG(WARNING) << "could not read dylinker error string from " << name_;
+  }
+}
+
+void MachOImageAnnotationsReader::ReadCrashpadSimpleAnnotations(
+    std::map<std::string, std::string>* simple_map_annotations) const {
+  mach_vm_address_t crashpad_info_address;
+  const process_types::section* crashpad_info_section =
+      image_reader_->GetSectionByName(
+          SEG_DATA, "__crashpad_info", &crashpad_info_address);
+  if (!crashpad_info_section) {
+    return;
+  }
+
+  process_types::CrashpadInfo crashpad_info;
+  if (crashpad_info_section->size <
+      crashpad_info.ExpectedSize(process_reader_)) {
+    LOG(WARNING) << "small crashpad info section size "
+                 << crashpad_info_section->size << " in " << name_;
+    return;
+  }
+
+  if (!crashpad_info.Read(process_reader_, crashpad_info_address)) {
+    LOG(WARNING) << "could not read crashpad info from " << name_;
+    return;
+  }
+
+  if (crashpad_info.signature != CrashpadInfo::kSignature ||
+      crashpad_info.size != crashpad_info_section->size ||
+      crashpad_info.version < 1) {
+    LOG(WARNING) << "unexpected crashpad info data in " << name_;
+    return;
+  }
+
+  if (!crashpad_info.simple_annotations) {
+    return;
+  }
+
+  std::vector<SimpleStringDictionary::Entry>
+      simple_annotations(SimpleStringDictionary::num_entries);
+  if (!process_reader_->Memory()
+           ->Read(crashpad_info.simple_annotations,
+                  simple_annotations.size() * sizeof(simple_annotations[0]),
+                  &simple_annotations[0])) {
+    LOG(WARNING) << "could not read simple annotations from " << name_;
+    return;
+  }
+
+  for (const auto& entry : simple_annotations) {
+    size_t key_length = strnlen(entry.key, sizeof(entry.key));
+    if (key_length) {
+      std::string key(entry.key, key_length);
+      std::string value(entry.value, strnlen(entry.value, sizeof(entry.value)));
+      if (!simple_map_annotations->count(key)) {
+        simple_map_annotations->insert(
+            std::pair<std::string, std::string>(key, value));
+      } else {
+        LOG(INFO) << "duplicate simple annotation " << key << " in " << name_;
+      }
+    }
+  }
+}
+
+}  // namespace crashpad

snapshot/mac/mach_o_image_annotations_reader.h

@@ -0,0 +1,92 @@
+// 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.
+
+#ifndef CRASHPAD_SNAPSHOT_MAC_MACH_O_IMAGE_ANNOTATIONS_READER_H_
+#define CRASHPAD_SNAPSHOT_MAC_MACH_O_IMAGE_ANNOTATIONS_READER_H_
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+
+namespace crashpad {
+
+class MachOImageReader;
+class ProcessReader;
+
+//! \brief A reader for annotations stored in a Mach-O image mapped into another
+//!     process.
+//!
+//! These annotations are stored for the benefit of crash reporters, and provide
+//! information though to be potentially useful for crash analysis. This class
+//! can decode annotations stored in these formats:
+//!  - CrashpadInfo. This format is used by Crashpad clients. The “simple
+//!    annotations” are recovered from any module with a compatible data
+//!    section, and are included in the annotations returned by SimpleMap().
+//!  - `CrashReporterClient.h`’s `crashreporter_annotations_t`. This format is
+//!    used by Apple code. The `message` and `message2` fields can be recovered
+//!    from any module with a compatible data section, and are included in the
+//!    annotations returned by Vector().
+//!  - `dyld`’s `error_string`. This format is used exclusively by dyld,
+//!    typically for fatal errors. This string can be recovered from any
+//!    `MH_DYLINKER`-type module with this symbol, and is included in the
+//!    annotations returned by Vector().
+class MachOImageAnnotationsReader {
+ public:
+  //! \brief Constructs an object.
+  //!
+  //! \param[in] process_reader The reader for the remote process.
+  //! \param[in] image_reader The MachOImageReader for the Mach-O image file
+  //!     contained within the remote process.
+  //! \param[in] name The module’s name, a string to be used in logged messages.
+  //!     This string is for diagnostic purposes only, and may be empty.
+  MachOImageAnnotationsReader(ProcessReader* process_reader,
+                              const MachOImageReader* image_reader,
+                              const std::string& name);
+
+  ~MachOImageAnnotationsReader() {}
+
+  //! \brief Returns the module’s annotations that are organized as a vector of
+  //!     strings.
+  std::vector<std::string> Vector() const;
+
+  //! \brief Returns the module’s annotations that are organized as key-value
+  //!     pairs, where all keys and values are strings.
+  std::map<std::string, std::string> SimpleMap() const;
+
+ private:
+  // Reades crashreporter_annotations_t::message and
+  // crashreporter_annotations_t::message2 on behalf of Vector().
+  void ReadCrashReporterClientAnnotations(
+      std::vector<std::string>* vector_annotations) const;
+
+  // Reads dyld_error_string on behalf of Vector().
+  void ReadDyldErrorStringAnnotation(
+      std::vector<std::string>* vector_annotations) const;
+
+  // Reads CrashpadInfo::simple_annotations_ on behalf of SimpleMap().
+  void ReadCrashpadSimpleAnnotations(
+      std::map<std::string, std::string>* simple_map_annotations) const;
+
+  std::string name_;
+  ProcessReader* process_reader_;  // weak
+  const MachOImageReader* image_reader_;  // weak
+
+  DISALLOW_COPY_AND_ASSIGN(MachOImageAnnotationsReader);
+};
+
+}  // namespace crashpad
+
+#endif  // CRASHPAD_SNAPSHOT_MAC_MACH_O_IMAGE_ANNOTATIONS_READER_H_

snapshot/mac/mach_o_image_annotations_reader_test.cc

@@ -0,0 +1,334 @@
+// 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/mac/mach_o_image_annotations_reader.h"
+
+#include <dlfcn.h>
+#include <mach/mach.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "client/crashpad_info.h"
+#include "client/simple_string_dictionary.h"
+#include "gtest/gtest.h"
+#include "snapshot/mac/process_reader.h"
+#include "util/file/fd_io.h"
+#include "util/mac/mac_util.h"
+#include "util/mach/exc_server_variants.h"
+#include "util/mach/exception_ports.h"
+#include "util/mach/mach_message_server.h"
+#include "util/test/errors.h"
+#include "util/test/mac/mach_errors.h"
+#include "util/test/mac/mach_multiprocess.h"
+
+namespace crashpad {
+namespace test {
+namespace {
+
+class TestMachOImageAnnotationsReader final : public MachMultiprocess,
+                                              public UniversalMachExcServer {
+ public:
+  enum TestType {
+    // Don’t crash, just test the CrashpadInfo interface.
+    kDontCrash = 0,
+
+    // The child process should crash by calling abort(). The parent verifies
+    // that the system libraries set the expected annotations.
+    kCrashAbort,
+
+    // The child process should crash by setting DYLD_INSERT_LIBRARIES to
+    // contain a nonexistent library. The parent verifies that dyld sets the
+    // expected annotations.
+    kCrashDyld,
+  };
+
+  explicit TestMachOImageAnnotationsReader(TestType test_type)
+      : MachMultiprocess(),
+        UniversalMachExcServer(),
+        test_type_(test_type) {
+  }
+
+  ~TestMachOImageAnnotationsReader() {}
+
+  // UniversalMachExcServer:
+  kern_return_t CatchMachException(exception_behavior_t behavior,
+                                   exception_handler_t exception_port,
+                                   thread_t thread,
+                                   task_t task,
+                                   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* old_state,
+                                   mach_msg_type_number_t old_state_count,
+                                   thread_state_t new_state,
+                                   mach_msg_type_number_t* new_state_count,
+                                   bool* destroy_complex_request) override {
+    *destroy_complex_request = true;
+
+    EXPECT_EQ(ChildTask(), task);
+
+    ProcessReader process_reader;
+    bool rv = process_reader.Initialize(task);
+    if (!rv) {
+      ADD_FAILURE();
+    } else {
+      const std::vector<ProcessReader::Module>& modules =
+          process_reader.Modules();
+      std::vector<std::string> all_annotations_vector;
+      for (const ProcessReader::Module& module : modules) {
+        MachOImageAnnotationsReader module_annotations_reader(
+            &process_reader, module.reader, module.name);
+        std::vector<std::string> module_annotations_vector =
+            module_annotations_reader.Vector();
+        all_annotations_vector.insert(all_annotations_vector.end(),
+                                      module_annotations_vector.begin(),
+                                      module_annotations_vector.end());
+      }
+
+      // Mac OS X 10.6 doesn’t have support for CrashReporter annotations
+      // (CrashReporterClient.h), so don’t look for any special annotations in
+      // that version.
+      int mac_os_x_minor_version = MacOSXMinorVersion();
+      if (mac_os_x_minor_version > 7) {
+        EXPECT_GE(all_annotations_vector.size(), 1u);
+
+        const char* expected_annotation = nullptr;
+        switch (test_type_) {
+          case kCrashAbort:
+            // The child process calls abort(), so the expected annotation
+            // reflects this, with a string set by 10.7.5
+            // Libc-763.13/stdlib/abort-fbsd.c abort(). This string is still
+            // present in 10.9.5 Libc-997.90.3/stdlib/FreeBSD/abort.c abort(),
+            // but because abort() tests to see if a message is already set and
+            // something else in Libc will have set a message, this string is
+            // not the expectation on 10.9 or higher. Instead, after fork(), the
+            // child process has a message indicating that a fork() without
+            // exec() occurred. See 10.9.5 Libc-997.90.3/sys/_libc_fork_child.c
+            // _libc_fork_child().
+            expected_annotation =
+                mac_os_x_minor_version <= 8
+                    ? "abort() called"
+                    : "crashed on child side of fork pre-exec";
+            break;
+
+          case kCrashDyld:
+            // This is independent of dyld’s error_string, which is tested
+            // below.
+            expected_annotation = "dyld: launch, loading dependent libraries";
+            break;
+
+          default:
+            ADD_FAILURE();
+            break;
+        }
+
+        size_t expected_annotation_length = strlen(expected_annotation);
+        bool found = false;
+        for (const std::string& annotation : all_annotations_vector) {
+          // Look for the expectation as a leading susbtring, because the actual
+          // string that dyld uses will have the contents of the
+          // DYLD_INSERT_LIBRARIES environment variable appended to it on Mac
+          // OS X 10.10.
+          if (annotation.substr(0, expected_annotation_length) ==
+                  expected_annotation) {
+            found = true;
+            break;
+          }
+        }
+        EXPECT_TRUE(found);
+      }
+
+      // dyld exposes its error_string at least as far back as Mac OS X 10.4.
+      if (test_type_ == kCrashDyld) {
+        const char kExpectedAnnotation[] = "could not load inserted library";
+        size_t expected_annotation_length = strlen(kExpectedAnnotation);
+        bool found = false;
+        for (const std::string& annotation : all_annotations_vector) {
+          // Look for the expectation as a leading substring, because the actual
+          // string will contain the library’s pathname and, on Mac OS X 10.9
+          // and later, a reason.
+          if (annotation.substr(0, expected_annotation_length) ==
+                  kExpectedAnnotation) {
+            found = true;
+            break;
+          }
+        }
+
+        EXPECT_TRUE(found);
+      }
+    }
+
+    return ExcServerSuccessfulReturnValue(behavior, false);
+  }
+
+ private:
+  // MachMultiprocess:
+
+  void MachMultiprocessParent() override {
+    ProcessReader process_reader;
+    ASSERT_TRUE(process_reader.Initialize(ChildTask()));
+
+    // Wait for the child process to indicate that it’s done setting up its
+    // annotations via the CrashpadInfo interface.
+    char c;
+    CheckedReadFD(ReadPipeFD(), &c, sizeof(c));
+
+    // Verify the “simple map” annotations set via the CrashpadInfo interface.
+    const std::vector<ProcessReader::Module>& modules =
+        process_reader.Modules();
+    std::map<std::string, std::string> all_annotations_simple_map;
+    for (const ProcessReader::Module& module : modules) {
+      MachOImageAnnotationsReader module_annotations_reader(
+          &process_reader, module.reader, module.name);
+      std::map<std::string, std::string> module_annotations_simple_map =
+          module_annotations_reader.SimpleMap();
+      all_annotations_simple_map.insert(module_annotations_simple_map.begin(),
+                                        module_annotations_simple_map.end());
+    }
+
+    EXPECT_GE(all_annotations_simple_map.size(), 5u);
+    EXPECT_EQ("crash", all_annotations_simple_map["#TEST# pad"]);
+    EXPECT_EQ("value", all_annotations_simple_map["#TEST# key"]);
+    EXPECT_EQ("y", all_annotations_simple_map["#TEST# x"]);
+    EXPECT_EQ("shorter", all_annotations_simple_map["#TEST# longer"]);
+    EXPECT_EQ("", all_annotations_simple_map["#TEST# empty_value"]);
+
+    // Tell the child process that it’s permitted to crash.
+    CheckedWriteFD(WritePipeFD(), &c, sizeof(c));
+
+    if (test_type_ != kDontCrash) {
+      // Handle the child’s crash. Further validation will be done in
+      // CatchMachException().
+      mach_msg_return_t mr =
+          MachMessageServer::Run(this,
+                                 LocalPort(),
+                                 MACH_MSG_OPTION_NONE,
+                                 MachMessageServer::kOneShot,
+                                 MachMessageServer::kBlocking,
+                                 MACH_MSG_TIMEOUT_NONE);
+      EXPECT_EQ(MACH_MSG_SUCCESS, mr)
+          << MachErrorMessage(mr, "MachMessageServer::Run");
+
+      switch (test_type_) {
+        case kCrashAbort:
+          SetExpectedChildTermination(kTerminationSignal, SIGABRT);
+          break;
+
+        case kCrashDyld:
+          // dyld fatal errors result in the execution of an int3 instruction on
+          // x86 and a trap instruction on ARM, both of which raise SIGTRAP.
+          // 10.9.5 dyld-239.4/src/dyldStartup.s _dyld_fatal_error.
+          SetExpectedChildTermination(kTerminationSignal, SIGTRAP);
+          break;
+
+        default:
+          FAIL();
+          break;
+      }
+    }
+  }
+
+  void MachMultiprocessChild() override {
+    CrashpadInfo* crashpad_info = CrashpadInfo::GetCrashpadInfo();
+
+    // This is “leaked” to crashpad_info.
+    SimpleStringDictionary* simple_annotations = new SimpleStringDictionary();
+    simple_annotations->SetKeyValue("#TEST# pad", "break");
+    simple_annotations->SetKeyValue("#TEST# key", "value");
+    simple_annotations->SetKeyValue("#TEST# pad", "crash");
+    simple_annotations->SetKeyValue("#TEST# x", "y");
+    simple_annotations->SetKeyValue("#TEST# longer", "shorter");
+    simple_annotations->SetKeyValue("#TEST# empty_value", "");
+
+    crashpad_info->set_simple_annotations(simple_annotations);
+
+    // Tell the parent that the environment has been set up.
+    char c = '\0';
+    CheckedWriteFD(WritePipeFD(), &c, sizeof(c));
+
+    // Wait for the parent to indicate that it’s safe to crash.
+    CheckedReadFD(ReadPipeFD(), &c, sizeof(c));
+
+    // Direct an exception message to the exception server running in the
+    // parent.
+    ExceptionPorts exception_ports(ExceptionPorts::kTargetTypeTask,
+                                   mach_task_self());
+    ASSERT_TRUE(exception_ports.SetExceptionPort(
+        EXC_MASK_CRASH, RemotePort(), EXCEPTION_DEFAULT, THREAD_STATE_NONE));
+
+    switch (test_type_) {
+      case kDontCrash:
+        break;
+
+      case kCrashAbort:
+        abort();
+        break;
+
+      case kCrashDyld: {
+        // Set DYLD_INSERT_LIBRARIES to contain a library that does not exist.
+        // Unable to load it, dyld will abort with a fatal error.
+        ASSERT_EQ(
+            0,
+            setenv(
+                "DYLD_INSERT_LIBRARIES", "/var/empty/NoDirectory/NoLibrary", 1))
+            << ErrnoMessage("setenv");
+
+        // The actual executable doesn’t matter very much, because dyld won’t
+        // ever launch it. It just needs to be an executable that uses dyld as
+        // its LC_LOAD_DYLINKER (all normal executables do). /usr/bin/true is on
+        // every system, so use it.
+        ASSERT_EQ(0, execl("/usr/bin/true", "true", nullptr))
+            << ErrnoMessage("execl");
+        break;
+      }
+
+      default:
+        break;
+    }
+  }
+
+  TestType test_type_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestMachOImageAnnotationsReader);
+};
+
+TEST(MachOImageAnnotationsReader, DontCrash) {
+  TestMachOImageAnnotationsReader test_mach_o_image_annotations_reader(
+      TestMachOImageAnnotationsReader::kDontCrash);
+  test_mach_o_image_annotations_reader.Run();
+}
+
+TEST(MachOImageAnnotationsReader, CrashAbort) {
+  TestMachOImageAnnotationsReader test_mach_o_image_annotations_reader(
+      TestMachOImageAnnotationsReader::kCrashAbort);
+  test_mach_o_image_annotations_reader.Run();
+}
+
+TEST(MachOImageAnnotationsReader, CrashDyld) {
+  TestMachOImageAnnotationsReader test_mach_o_image_annotations_reader(
+      TestMachOImageAnnotationsReader::kCrashDyld);
+  test_mach_o_image_annotations_reader.Run();
+}
+
+}  // namespace
+}  // namespace test
+}  // namespace crashpad

snapshot/mac/mach_o_image_reader.h

@@ -39,6 +39,8 @@ class ProcessReader;
 //! This class is capable of reading both 32-bit (`mach_header`/`MH_MAGIC`) and
 //! 64-bit (`mach_header_64`/`MH_MAGIC_64`) images based on the bitness of the
 //! remote process.
+//!
+//! \sa MachOImageAnnotationsReader
 class MachOImageReader {
  public:
   MachOImageReader();

snapshot/mac/process_reader.cc

@@ -400,13 +400,14 @@ void ProcessReader::InitializeModules() {
   //
   // TODO(mark): It may be possible to recover from these situations by looking
   // through memory mappings for Mach-O images.
+  //
+  // Continue along when this situation is detected, because even without any
+  // images in infoArray, dyldImageLoadAddress may be set, and it may be
+  // possible to recover some information from dyld.
   if (all_image_infos.infoArrayCount == 0) {
     LOG(WARNING) << "all_image_infos.infoArrayCount is zero";
-    return;
-  }
-  if (!all_image_infos.infoArray) {
+  } else if (!all_image_infos.infoArray) {
     LOG(WARNING) << "all_image_infos.infoArray is nullptr";
-    return;
   }
 
   std::vector<process_types::dyld_image_info> image_info_vector(

snapshot/mac/process_types/all.proctype

@@ -19,6 +19,7 @@
 // snapshot/mac/process_types.cc to produce process type struct definitions and
 // accessors.
 
+#include "snapshot/mac/process_types/crashpad_info.proctype"
 #include "snapshot/mac/process_types/crashreporterclient.proctype"
 #include "snapshot/mac/process_types/dyld_images.proctype"
 #include "snapshot/mac/process_types/loader.proctype"

snapshot/mac/process_types/crashpad_info.proctype

@@ -0,0 +1,34 @@
+// 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.
+
+// The file corresponds to Crashpad’s client/crashpad_info.h.
+//
+// This file is intended to be included multiple times in the same translation
+// unit, so #include guards are intentionally absent.
+//
+// This file is included by snapshot/mac/process_types.h and
+// snapshot/mac/process_types.cc to produce process type struct definitions and
+// accessors.
+
+// Client Mach-O images will contain a __DATA,__crashpad_info section formatted
+// according to this structure.
+PROCESS_TYPE_STRUCT_BEGIN(CrashpadInfo)
+  PROCESS_TYPE_STRUCT_MEMBER(uint32_t, signature)
+  PROCESS_TYPE_STRUCT_MEMBER(uint32_t, size)
+  PROCESS_TYPE_STRUCT_MEMBER(uint32_t, version)
+  PROCESS_TYPE_STRUCT_MEMBER(uint32_t, padding_0)
+
+  // SimpleStringDictionary*
+  PROCESS_TYPE_STRUCT_MEMBER(Pointer, simple_annotations)
+PROCESS_TYPE_STRUCT_END(CrashpadInfo)

snapshot/snapshot.gyp

@@ -18,6 +18,7 @@
       'target_name': 'snapshot',
       'type': 'static_library',
       'dependencies': [
+        '../client/client.gyp:client',
         '../compat/compat.gyp:compat',
         '../third_party/mini_chromium/mini_chromium/base/base.gyp:base',
         '../util/util.gyp:util',
@@ -34,6 +35,8 @@
         'mac/cpu_context_mac.h',
         'mac/exception_snapshot_mac.cc',
         'mac/exception_snapshot_mac.h',
+        'mac/mach_o_image_annotations_reader.cc',
+        'mac/mach_o_image_annotations_reader.h',
         'mac/mach_o_image_reader.cc',
         'mac/mach_o_image_reader.h',
         'mac/mach_o_image_segment_reader.cc',
@@ -47,6 +50,7 @@
         'mac/process_types.cc',
         'mac/process_types.h',
         'mac/process_types/all.proctype',
+        'mac/process_types/crashpad_info.proctype',
         'mac/process_types/crashreporterclient.proctype',
         'mac/process_types/custom.cc',
         'mac/process_types/dyld_images.proctype',
@@ -71,6 +75,7 @@
       'type': 'executable',
       'dependencies': [
         'snapshot',
+        '../client/client.gyp:client',
         '../compat/compat.gyp:compat',
         '../third_party/gtest/gtest.gyp:gtest',
         '../third_party/gtest/gtest.gyp:gtest_main',
@@ -83,6 +88,7 @@
       ],
       'sources': [
         'mac/cpu_context_mac_test.cc',
+        'mac/mach_o_image_annotations_reader_test.cc',
         'mac/mach_o_image_reader_test.cc',
         'mac/mach_o_image_segment_reader_test.cc',
         'mac/process_reader_test.cc',