src/developer/forensics/feedback_data/tests/zx_object_util.cc

// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/developer/forensics/feedback_data/tests/zx_object_util.h"

#include <lib/syslog/cpp/macros.h>
#include <zircon/errors.h>
#include <zircon/syscalls.h>
#include <zircon/types.h>

#include <cstdint>
#include <vector>

namespace forensics {
namespace feedback_data {
namespace {

std::vector<zx_koid_t> GetChildKoids(const zx_handle_t parent, zx_object_info_topic_t child_kind) {
  std::vector<zx_koid_t> result(100);  // 100 ought to be enough for tests.
  size_t actual = 0;
  size_t available = 0;
  FX_CHECK(zx_object_get_info(parent, child_kind, result.data(), result.size() * sizeof(result[0]),
                              &actual, &available) == ZX_OK);
  FX_CHECK(actual == available);
  result.resize(actual);
  return result;
}

template <typename ResultObject>
std::vector<ResultObject> GetChildObjects(const zx_handle_t parent, uint32_t child_kind) {
  auto koids = GetChildKoids(parent, child_kind);

  std::vector<ResultObject> result;
  result.reserve(koids.size());
  for (const auto& koid : koids) {
    zx_handle_t handle;
    // The child object could be already gone since we asked for the child koids so only push the
    // children for which we can get a handle to.
    // This actually happened in practice where "feedback_data_provider" processes are expected to
    // be cleaned up and sometimes the clean up happens after GetChildKoids(), cf. fxbug.dev/39174.
    if (zx_object_get_child(parent, koid, ZX_RIGHT_SAME_RIGHTS, &handle) == ZX_OK) {
      result.push_back(ResultObject(handle));
    }
  }
  return result;
}

}  // namespace

std::vector<zx::job> GetChildJobs(const zx_handle_t job) {
  return GetChildObjects<zx::job>(job, ZX_INFO_JOB_CHILDREN);
}

std::vector<zx::process> GetChildProcesses(const zx_handle_t job) {
  return GetChildObjects<zx::process>(job, ZX_INFO_JOB_PROCESSES);
}

}  // namespace feedback_data
}  // namespace forensics