src/trace_redaction/find_package_uid.cc

/*
 * Copyright (C) 2024 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 "src/trace_redaction/find_package_uid.h"
#include "perfetto/ext/base/string_view.h"
#include "src/trace_redaction/trace_redaction_framework.h"

#include "protos/perfetto/trace/android/packages_list.pbzero.h"
#include "protos/perfetto/trace/trace_packet.pbzero.h"

namespace perfetto::trace_redaction {

base::Status FindPackageUid::Begin(Context* context) const {
  if (context->package_name.empty()) {
    return base::ErrStatus("FindPackageUid: missing package name.");
  }

  if (context->package_uid.has_value()) {
    return base::ErrStatus("FindPackageUid: package uid already found.");
  }

  return base::OkStatus();
}

base::Status FindPackageUid::Collect(
    const protos::pbzero::TracePacket::Decoder& packet,
    Context* context) const {
  // If a package has been found in a pervious iteration, stop.
  if (context->package_uid.has_value()) {
    return base::OkStatus();
  }

  if (!packet.has_packages_list()) {
    return base::OkStatus();
  }

  protos::pbzero::PackagesList::Decoder packages_list_decoder(
      packet.packages_list());

  for (auto package = packages_list_decoder.packages(); package; ++package) {
    protos::pbzero::PackagesList::PackageInfo::Decoder info(*package);

    if (!info.has_name() || !info.uid()) {
      continue;
    }

    // Package names should be lowercase, but this check is meant to be more
    // forgiving.
    base::StringView expected_name(context->package_name.data(),
                                   context->package_name.size());
    base::StringView actual_name(info.name().data, info.name().size);
    if (!actual_name.CaseInsensitiveEq(expected_name)) {
      continue;
    }

    // See "trace_redaction_framework.cc" for info.uid() must be normalized.
    context->package_uid = NormalizeUid(info.uid());
    return base::OkStatus();
  }

  // Nothing was found. There should only be one package list, but we keep
  // looking just incase. The error case will be handled in End().
  return base::OkStatus();
}

base::Status FindPackageUid::End(Context* context) const {
  if (!context->package_uid.has_value()) {
    return base::ErrStatus("FindPackageUid: did not find package uid.");
  }

  return base::OkStatus();
}

}  // namespace perfetto::trace_redaction