Add crashpad_info, MachOImageAnnotationsReader, and its test

snapshot/mac/mach_o_image_annotations_reader.cc

+// 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