platform_system_core/init/service_test.cpp
Tom Cherry 62ca663475 init: introduce Result<T> for return values and error handling
init tries to propagate error information up to build context before
logging errors.  This is a good thing, however too often init has the
overly verbose paradigm for error handling, below:

bool CalculateResult(const T& input, U* output, std::string* err)

bool CalculateAndUseResult(const T& input, std::string* err) {
  U output;
  std::string calculate_result_err;
  if (!CalculateResult(input, &output, &calculate_result_err)) {
    *err = "CalculateResult " + input + " failed: " +
      calculate_result_err;
      return false;
  }
  UseResult(output);
  return true;
}

Even more common are functions that return only true/false but also
require passing a std::string* err in order to see the error message.

This change introduces a Result<T> that is use to either hold a
successful return value of type T or to hold an error message as a
std::string.  If the functional only returns success or a failure with
an error message, Result<Success> may be used.  The classes Error and
ErrnoError are used to indicate a failed Result<T>.

A successful Result<T> is constructed implicitly from any type that
can be implicitly converted to T or from the constructor arguments for
T.  This allows you to return a type T directly from a function that
returns Result<T>.

Error and ErrnoError are used to construct a Result<T> has
failed. Each of these classes take an ostream as an input and are
implicitly cast to a Result<T> containing that failure.  ErrnoError()
additionally appends ": " + strerror(errno) to the end of  the failure
string to aid in interacting with C APIs.

The end result is that the above code snippet is turned into the much
clearer example below:

Result<U> CalculateResult(const T& input);

Result<Success> CalculateAndUseResult(const T& input) {
  auto output = CalculateResult(input);
  if (!output) {
    return Error() << "CalculateResult " << input << " failed: "
                   << output.error();
  }
  UseResult(*output);
  return Success();
}

This change also makes this conversion for some of the util.cpp
functions that used the old paradigm.

Test: boot bullhead, init unit tests
Change-Id: I1e7d3a8820a79362245041251057fbeed2f7979b
2017-08-14 10:26:57 -07:00

192 lines
6.5 KiB
C++

/*
* Copyright (C) 2017 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 "service.h"
#include <algorithm>
#include <memory>
#include <type_traits>
#include <vector>
#include <gtest/gtest.h>
#include "util.h"
namespace android {
namespace init {
TEST(service, pod_initialized) {
constexpr auto memory_size = sizeof(Service);
alignas(alignof(Service)) char old_memory[memory_size];
for (std::size_t i = 0; i < memory_size; ++i) {
old_memory[i] = 0xFF;
}
std::vector<std::string> dummy_args{"/bin/test"};
Service* service_in_old_memory = new (old_memory) Service("test_old_memory", dummy_args);
EXPECT_EQ(0U, service_in_old_memory->flags());
EXPECT_EQ(0, service_in_old_memory->pid());
EXPECT_EQ(0, service_in_old_memory->crash_count());
EXPECT_EQ(0U, service_in_old_memory->uid());
EXPECT_EQ(0U, service_in_old_memory->gid());
EXPECT_EQ(0U, service_in_old_memory->namespace_flags());
EXPECT_EQ(0, service_in_old_memory->keychord_id());
EXPECT_EQ(IoSchedClass_NONE, service_in_old_memory->ioprio_class());
EXPECT_EQ(0, service_in_old_memory->ioprio_pri());
EXPECT_EQ(0, service_in_old_memory->priority());
EXPECT_EQ(-1000, service_in_old_memory->oom_score_adjust());
EXPECT_FALSE(service_in_old_memory->process_cgroup_empty());
for (std::size_t i = 0; i < memory_size; ++i) {
old_memory[i] = 0xFF;
}
Service* service_in_old_memory2 = new (old_memory)
Service("test_old_memory", 0U, 0U, 0U, std::vector<gid_t>(), CapSet(), 0U, "", dummy_args);
EXPECT_EQ(0U, service_in_old_memory2->flags());
EXPECT_EQ(0, service_in_old_memory2->pid());
EXPECT_EQ(0, service_in_old_memory2->crash_count());
EXPECT_EQ(0U, service_in_old_memory2->uid());
EXPECT_EQ(0U, service_in_old_memory2->gid());
EXPECT_EQ(0U, service_in_old_memory2->namespace_flags());
EXPECT_EQ(0, service_in_old_memory2->keychord_id());
EXPECT_EQ(IoSchedClass_NONE, service_in_old_memory2->ioprio_class());
EXPECT_EQ(0, service_in_old_memory2->ioprio_pri());
EXPECT_EQ(0, service_in_old_memory2->priority());
EXPECT_EQ(-1000, service_in_old_memory2->oom_score_adjust());
EXPECT_FALSE(service_in_old_memory->process_cgroup_empty());
}
TEST(service, make_temporary_oneshot_service_invalid_syntax) {
std::vector<std::string> args;
// Nothing.
ASSERT_EQ(nullptr, Service::MakeTemporaryOneshotService(args));
// No arguments to 'exec'.
args.push_back("exec");
ASSERT_EQ(nullptr, Service::MakeTemporaryOneshotService(args));
// No command in "exec --".
args.push_back("--");
ASSERT_EQ(nullptr, Service::MakeTemporaryOneshotService(args));
}
TEST(service, make_temporary_oneshot_service_too_many_supplementary_gids) {
std::vector<std::string> args;
args.push_back("exec");
args.push_back("seclabel");
args.push_back("root"); // uid.
args.push_back("root"); // gid.
for (int i = 0; i < NR_SVC_SUPP_GIDS; ++i) {
args.push_back("root"); // Supplementary gid.
}
args.push_back("--");
args.push_back("/system/bin/id");
ASSERT_EQ(nullptr, Service::MakeTemporaryOneshotService(args));
}
static void Test_make_temporary_oneshot_service(bool dash_dash, bool seclabel, bool uid, bool gid,
bool supplementary_gids) {
std::vector<std::string> args;
args.push_back("exec");
if (seclabel) {
args.push_back("u:r:su:s0"); // seclabel
if (uid) {
args.push_back("log"); // uid
if (gid) {
args.push_back("shell"); // gid
if (supplementary_gids) {
args.push_back("system"); // supplementary gid 0
args.push_back("adb"); // supplementary gid 1
}
}
}
}
if (dash_dash) {
args.push_back("--");
}
args.push_back("/system/bin/toybox");
args.push_back("id");
auto svc = Service::MakeTemporaryOneshotService(args);
ASSERT_NE(nullptr, svc);
if (seclabel) {
ASSERT_EQ("u:r:su:s0", svc->seclabel());
} else {
ASSERT_EQ("", svc->seclabel());
}
if (uid) {
auto decoded_uid = DecodeUid("log");
ASSERT_TRUE(decoded_uid);
ASSERT_EQ(*decoded_uid, svc->uid());
} else {
ASSERT_EQ(0U, svc->uid());
}
if (gid) {
auto decoded_uid = DecodeUid("shell");
ASSERT_TRUE(decoded_uid);
ASSERT_EQ(*decoded_uid, svc->gid());
} else {
ASSERT_EQ(0U, svc->gid());
}
if (supplementary_gids) {
ASSERT_EQ(2U, svc->supp_gids().size());
auto decoded_uid = DecodeUid("system");
ASSERT_TRUE(decoded_uid);
ASSERT_EQ(*decoded_uid, svc->supp_gids()[0]);
decoded_uid = DecodeUid("adb");
ASSERT_TRUE(decoded_uid);
ASSERT_EQ(*decoded_uid, svc->supp_gids()[1]);
} else {
ASSERT_EQ(0U, svc->supp_gids().size());
}
ASSERT_EQ(static_cast<std::size_t>(2), svc->args().size());
ASSERT_EQ("/system/bin/toybox", svc->args()[0]);
ASSERT_EQ("id", svc->args()[1]);
}
TEST(service, make_temporary_oneshot_service_with_everything) {
Test_make_temporary_oneshot_service(true, true, true, true, true);
}
TEST(service, make_temporary_oneshot_service_with_seclabel_uid_gid) {
Test_make_temporary_oneshot_service(true, true, true, true, false);
}
TEST(service, make_temporary_oneshot_service_with_seclabel_uid) {
Test_make_temporary_oneshot_service(true, true, true, false, false);
}
TEST(service, make_temporary_oneshot_service_with_seclabel) {
Test_make_temporary_oneshot_service(true, true, false, false, false);
}
TEST(service, make_temporary_oneshot_service_with_just_command) {
Test_make_temporary_oneshot_service(true, false, false, false, false);
}
TEST(service, make_temporary_oneshot_service_with_just_command_no_dash) {
Test_make_temporary_oneshot_service(false, false, false, false, false);
}
} // namespace init
} // namespace android