Add crashpad_info, MachOImageAnnotationsReader, and its test

util/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 "util/mac/mach_o_image_annotations_reader.h"
+
+#include <mach-o/loader.h>
+#include <mach/mach.h>
+
+#include "base/logging.h"
+#include "util/mac/mach_o_image_reader.h"
+#include "util/mac/process_reader.h"
+#include "util/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(

[Robert Sesek, 2014/10/15 20:25:20]

nit: break after ( instead of -> ?

+                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;
+  if (process_reader_->Memory()
+          ->ReadCStringSizeLimited(error_string_address, 1024, &message)) {

[Robert Sesek, 2014/10/15 20:25:20]

Globalize and use the kMaxMessageSize from above.

[Mark Mentovai, 2014/10/15 21:20:21]

Robert Sesek wrote:
But they are different sizes. We could reasonably raise the one above to 2048 or
16384 or remove it entirely, but this one should stay 1024, because that’s how
it’s declared in dyld.

+    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 != 'cpad' ||
+      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;
+  }
+
+  struct Entry {

[Robert Sesek, 2014/10/15 20:25:20]

Why not use SimpleStringDictionary::Entry here?

[Mark Mentovai, 2014/10/15 21:20:21]

Robert Sesek wrote:
Layering violation…util shouldn’t depend on client.

Should we move SimpleStringDictionary into util? I thought about it, but it’s
really only useful in client, except for the constants. I would never expect any
code outside of client to use the SimpleStringDictionary implementation.

+    char key[256];
+    char value[256];
+  };
+  const size_t kNumEntries = 64;

[Robert Sesek, 2014/10/15 20:25:20]

Similarly, SimpleStringDictionary::num_entries.

+  std::vector<Entry> simple_annotations(kNumEntries);
+  if (!process_reader_->Memory()
+           ->Read(crashpad_info.simple_annotations,
+                  sizeof(Entry) * kNumEntries,
+                  &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