Interceptor: initial analysis tooling

Add analysis tooling to process interceptor logs. As a first utility,
add --output-type text to dump the log as pb text.

Bug: 205577427
Signed-off-by: Matthias Maennich <maennich@google.com>
Change-Id: I10b3e46df6b7deb070710aa4ac9ab94a5486d43a

3 files changed, 130 insertions, 0 deletions

diff --git a/build-prebuilts.sh b/build-prebuilts.sh
index 4a061c2..8925111 100755
--- a/build-prebuilts.sh
+++ b/build-prebuilts.sh
@@ -37,6 +37,7 @@ EOF
         e2fsdroid
         img2simg
         interceptor
+        interceptor_analysis
         lpmake
         lz4
         mkbootfs
diff --git a/interceptor/Android.bp b/interceptor/Android.bp
index 56ea6b2..e944816 100644
--- a/interceptor/Android.bp
+++ b/interceptor/Android.bp
@@ -32,3 +32,9 @@ cc_binary_host {
     srcs: ["main.cc"],
     defaults: ["interceptor_defaults"],
 }
+
+cc_binary_host {
+    name: "interceptor_analysis",
+    srcs: ["analysis.cc",],
+    defaults: ["interceptor_defaults",],
+}
diff --git a/interceptor/analysis.cc b/interceptor/analysis.cc
new file mode 100644
index 0000000..b7f1535
--- /dev/null
+++ b/interceptor/analysis.cc
@@ -0,0 +1,123 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * 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 <getopt.h>
+#include <google/protobuf/text_format.h>
+#include <sysexits.h>
+#include <cstdlib>
+#include <cstring>
+#include <filesystem>
+#include <fstream>
+#include <iostream>
+#include <iterator>
+
+#include "log.pb.h"
+
+namespace fs = std::filesystem;
+
+enum class OutputFormat { TEXT };
+
+struct Options {
+  fs::path command_log;
+  OutputFormat output_format = OutputFormat::TEXT;
+  fs::path output;
+};
+
+static Options parse_args(int argc, char* argv[]) {
+  Options result;
+
+  const static option opts[] = {
+      {"command-log", required_argument, nullptr, 'l'},
+      {"output-type", required_argument, nullptr, 't'},
+      {"output", required_argument, nullptr, 'o'},
+      {nullptr, 0, nullptr, 0},
+  };
+  const auto usage = [&]() {
+    std::cerr << "usage: " << argv[0] << '\n'
+              << "  -l|--command-log filename\n"
+              << "  -o|--output filename\n"
+              << " [-t|--output-type (text)]\n";
+    exit(EX_USAGE);
+  };
+  while (true) {
+    int ix;
+    int c = getopt_long(argc, argv, "-l:f:o:", opts, &ix);
+    if (c == -1) break;
+    switch (c) {
+      case 'l':
+        result.command_log = fs::absolute(optarg);
+        break;
+      case 't':
+        if (strcmp(optarg, "text") == 0)
+          result.output_format = OutputFormat::TEXT;
+        else
+          usage();
+        break;
+      case 'o':
+        result.output = fs::absolute(optarg);
+        break;
+      default:
+        usage();
+    }
+  }
+
+  if (result.command_log.empty() || result.output.empty()) {
+    usage();
+  }
+
+  if (!fs::exists(result.command_log)) {
+    std::cerr << "No such file: " << result.command_log << "\n";
+  }
+
+  return result;
+}
+
+interceptor::log::Log read_log(const fs::path& log_file) {
+  interceptor::log::Log result;
+  std::ifstream input(log_file);
+  if (!input) {
+    std::cerr << "Could not open input file for reading.\n";
+    exit(EX_NOINPUT);
+  }
+  result.ParseFromIstream(&input);
+  return result;
+}
+
+void text_to_file(const interceptor::log::Log& log, const fs::path& output) {
+  std::string content;
+  google::protobuf::TextFormat::PrintToString(log, &content);
+  std::ofstream os(output);
+  if (!os) {
+    std::cerr << "Could not open output file for writing.\n";
+    exit(EX_CANTCREAT);
+  }
+  os << content;
+  if (!os.flush()) {
+    std::cerr << "Failed to write to output file.\n";
+    exit(EX_CANTCREAT);
+  }
+}
+
+int main(int argc, char* argv[]) {
+  const auto options = parse_args(argc, argv);
+  const auto log = read_log(options.command_log);
+
+  switch (options.output_format) {
+    case OutputFormat::TEXT:
+      text_to_file(log, options.output);
+      break;
+  }
+}