adds the afl instrumenter.

syzygy/instrument/instrumenters/afl_instrumenter.cc

+// Copyright 2017 Google Inc. 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 "syzygy/instrument/instrumenters/afl_instrumenter.h"
+
+#include "base/logging.h"
+#include "base/values.h"
+#include "base/files/file_util.h"
+#include "base/json/json_reader.h"
+#include "syzygy/application/application.h"
+#include "syzygy/common/indexed_frequency_data.h"
+
+namespace instrument {
+namespace instrumenters {
+
+bool AFLInstrumenter::ReadFromJSON(const std::string& json) {
+  std::unique_ptr<base::Value> value(base::JSONReader::Read(json).release());
+
+  if (value.get() == nullptr) {
+    LOG(ERROR) << "Invalid or empty JSON configuration.";
+    return false;
+  }
+
+  if (!value->IsType(base::Value::TYPE_DICTIONARY)) {
+    LOG(ERROR) << "Invalid JSON configuration.";
+    return false;
+  }

[chrisha, 2017/06/28 18:20:03]

You could fold these two checks into a single check and a single message:

if (!value || value->IsType(...)) {
  LOG(ERROR) << "...";
  return false;
}

[0vercl0k, 2017/06/29 02:39:14]

Done.

+
+  const base::DictionaryValue* outer_dict =
+      reinterpret_cast<const base::DictionaryValue*>(value.get());
+
+  const base::ListValue* whitelist = nullptr, * blacklist = nullptr,
+                         * to_parse_list = nullptr;

[chrisha, 2017/06/28 18:20:04]

Strong preference for repeating the const "base::ListValue*" type, and putting
one variable per line (more readable).

[0vercl0k, 2017/06/29 02:39:14]

Done.

+
+  outer_dict->GetList("whitelist", &whitelist);
+  outer_dict->GetList("blacklist", &blacklist);
+
+  if (whitelist == nullptr && blacklist == nullptr) {
+    LOG(ERROR) << "JSON file must contain either 'whitelist' or 'blacklist'.";
+    return false;
+  }
+
+  if (whitelist != nullptr && blacklist != nullptr) {
+    LOG(ERROR) << "'whitelist' and 'blacklist' are mutally exclusive.";
+    return false;
+  }
+
+  whitelist_mode_ = whitelist != nullptr;
+  if (whitelist_mode_) {
+    to_parse_list = whitelist;
+  } else {
+    to_parse_list = blacklist;
+  }
+
+  base::ListValue::const_iterator list_iter = to_parse_list->begin();
+  for (; list_iter != to_parse_list->end(); ++list_iter) {
+    std::string fname;
+    if (!(*list_iter)->GetAsString(&fname)) {
+      LOG(WARNING) << "The list must be composed of strings only, ignoring.";

[chrisha, 2017/06/28 18:20:03]

If this is truly a warning, you probably only want to emit it once, otherwise
you could flood the screen with these warnings. I'd prefer this be a hard
failure, as malformed input.

[0vercl0k, 2017/06/29 02:39:14]

Done.

+      continue;
+    }
+
+    target_set_.insert(fname);
+  }
+
+  if (target_set_.size() == 0) {
+    LOG(ERROR) << "List cannot be empty.";
+    return false;
+  }
+
+  return true;
+}
+
+bool AFLInstrumenter::ReadFromJSONPath(const base::FilePath& path) {
+  std::string file_string;
+  if (!base::ReadFileToString(path, &file_string)) {
+    LOG(ERROR) << "Unable to read file to string.";
+    return false;
+  }
+
+  if (!ReadFromJSON(file_string)) {
+    LOG(ERROR) << "Unable to parse JSON string.";
+    return false;
+  }
+
+  return true;
+}
+
+bool AFLInstrumenter::DoCommandLineParse(
+    const base::CommandLine* command_line) {
+  if (!Super::DoCommandLineParse(command_line))
+    return false;
+
+  // Parse the config path parameter (optional).
+  if (command_line->HasSwitch("config")) {
+    base::FilePath config_path = application::AppImplBase::AbsolutePath(
+        command_line->GetSwitchValuePath("config"));
+
+    if (!ReadFromJSONPath(config_path)) {
+      LOG(ERROR) << "Unable to parse JSON file.";
+      return false;
+    }
+  }
+
+  // Parse the force decomposition flag (optional).
+  force_decomposition_ = command_line->HasSwitch("force-decompose");
+  if (force_decomposition_) {
+    LOG(INFO) << "Force decomposition mode enabled.";
+  }
+
+  // Parse the multithread flag (optional).
+  multithread_mode_ = command_line->HasSwitch("multithread");
+  if (multithread_mode_) {
+    LOG(INFO) << "Thread-safe instrumentation mode enabled.";
+  }
+
+  // Parse the cookie check hook flag (optional).
+  cookie_check_hook_ = command_line->HasSwitch("cookie-check-hook");
+  if (cookie_check_hook_) {
+    LOG(INFO) << "Cookie check hook mode enabled.";
+  }
+
+  return true;
+}
+
+bool AFLInstrumenter::InstrumentPrepare() {
+  return true;
+}
+
+bool AFLInstrumenter::InstrumentImpl() {
+  transformer_.reset(new instrument::transforms::AFLTransform(
+      target_set_, whitelist_mode_, force_decomposition_, multithread_mode_,
+      cookie_check_hook_));
+
+  if (!relinker_->AppendTransform(transformer_.get())) {
+    LOG(ERROR) << "AppendTransform failed.";
+    return false;
+  }
+
+  add_bb_addr_stream_mutator_.reset(
+      new instrument::mutators::AddIndexedDataRangesStreamPdbMutator(
+          transformer_->bb_ranges(), common::kBasicBlockRangesStreamName));
+
+  if (!relinker_->AppendPdbMutator(add_bb_addr_stream_mutator_.get())) {
+    LOG(ERROR) << "AppendPdbMutator failed.";
+    return false;
+  }
+
+  return true;
+}
+
+const char* AFLInstrumenter::InstrumentationMode() {
+  return "afl";
+}
+}  // namespace instrumenters
+}  // namespace instrument