absl/log/stripping_test.cc - third_party/abseil-cpp - Git at Google

 //
 // Copyright 2022 The Abseil Authors.
 //
 // 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
 //
 //      https://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.
 //
 // Tests for stripping of literal strings.
 // ---------------------------------------
 //
 // When a `LOG` statement can be trivially proved at compile time to never fire,
 // e.g. due to `ABSL_MIN_LOG_LEVEL`, `NDEBUG`, or some explicit condition, data
 // streamed in can be dropped from the compiled program completely if they are
 // not used elsewhere.  This most commonly affects string literals, which users
 // often want to strip to reduce binary size and/or redact information about
 // their program's internals (e.g. in a release build).
 //
 // These tests log strings and then validate whether they appear in the compiled
 // binary.  This is done by opening the file corresponding to the running test
 // and running a simple string search on its contents.  The strings to be logged
 // and searched for must be unique, and we must take care not to emit them into
 // the binary in any other place, e.g. when searching for them.  The latter is
 // accomplished by computing them using base64; the source string appears in the
 // binary but the target string is computed at runtime.

 #include <stdio.h>

 #if defined(__MACH__)
 #include <mach-o/dyld.h>
 #elif defined(_WIN32)
 #include <Windows.h>
 #include <tchar.h>
 #endif

 #include <algorithm>
 #include <functional>
 #include <memory>
 #include <ostream>
 #include <string>

 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
 #include "absl/base/internal/strerror.h"
 #include "absl/base/log_severity.h"
 #include "absl/flags/internal/program_name.h"
 #include "absl/log/check.h"
 #include "absl/log/internal/test_helpers.h"
 #include "absl/log/log.h"
 #include "absl/status/status.h"
 #include "absl/strings/escaping.h"
 #include "absl/strings/str_format.h"
 #include "absl/strings/string_view.h"

 // Set a flag that controls whether we actually execute fatal statements, but
 // prevent the compiler from optimizing it out.
 static volatile bool kReallyDie = false;

 namespace {
 using ::testing::_;
 using ::testing::Eq;
 using ::testing::NotNull;

 using absl::log_internal::kAbslMinLogLevel;

 std::string Base64UnescapeOrDie(absl::string_view data) {
   std::string decoded;
   CHECK(absl::Base64Unescape(data, &decoded));
   return decoded;
 }

 // -----------------------------------------------------------------------------
 // A Googletest matcher which searches the running binary for a given string
 // -----------------------------------------------------------------------------

 // This matcher is used to validate that literal strings streamed into
 // `LOG` statements that ought to be compiled out (e.g. `LOG_IF(INFO, false)`)
 // do not appear in the binary.
 //
 // Note that passing the string to be sought directly to `FileHasSubstr()` all
 // but forces its inclusion in the binary regardless of the logging library's
 // behavior. For example:
 //
 //   LOG_IF(INFO, false) << "you're the man now dog";
 //   // This will always pass:
 //   // EXPECT_THAT(fp, FileHasSubstr("you're the man now dog"));
 //   // So use this instead:
 //   EXPECT_THAT(fp, FileHasSubstr(
 //       Base64UnescapeOrDie("eW91J3JlIHRoZSBtYW4gbm93IGRvZw==")));

 class FileHasSubstrMatcher final : public ::testing::MatcherInterface<FILE*> {
  public:
   explicit FileHasSubstrMatcher(absl::string_view needle) : needle_(needle) {}

   bool MatchAndExplain(
       FILE* fp, ::testing::MatchResultListener* listener) const override {
     std::string buf(
         std::max<std::string::size_type>(needle_.size() * 2, 163840000), '\0');
     size_t buf_start_offset = 0;  // The file offset of the byte at `buf[0]`.
     size_t buf_data_size = 0;     // The number of bytes of `buf` which contain
                                   // data.

     ::fseek(fp, 0, SEEK_SET);
     while (true) {
       // Fill the buffer to capacity or EOF:
       while (buf_data_size < buf.size()) {
         const size_t ret = fread(&buf[buf_data_size], sizeof(char),
                                  buf.size() - buf_data_size, fp);
         if (ret == 0) break;
         buf_data_size += ret;
       }
       if (ferror(fp)) {
         *listener << "error reading file";
         return false;
       }
       const absl::string_view haystack(&buf[0], buf_data_size);
       const auto off = haystack.find(needle_);
       if (off != haystack.npos) {
         *listener << "string found at offset " << buf_start_offset + off;
         return true;
       }
       if (feof(fp)) {
         *listener << "string not found";
         return false;
       }
       // Copy the end of `buf` to the beginning so we catch matches that span
       // buffer boundaries.  `buf` and `buf_data_size` are always large enough
       // that these ranges don't overlap.
       memcpy(&buf[0], &buf[buf_data_size - needle_.size()], needle_.size());
       buf_start_offset += buf_data_size - needle_.size();
       buf_data_size = needle_.size();
     }
   }
   void DescribeTo(std::ostream* os) const override {
     *os << "contains the string \"" << needle_ << "\" (base64(\""
         << Base64UnescapeOrDie(needle_) << "\"))";
   }

   void DescribeNegationTo(std::ostream* os) const override {
     *os << "does not ";
     DescribeTo(os);
   }

  private:
   std::string needle_;
 };

 class StrippingTest : public ::testing::Test {
  protected:
   void SetUp() override {
 #ifndef NDEBUG
     // Non-optimized builds don't necessarily eliminate dead code at all, so we
     // don't attempt to validate stripping against such builds.
     GTEST_SKIP() << "StrippingTests skipped since this build is not optimized";
 #elif defined(__EMSCRIPTEN__)
     // These tests require a way to examine the running binary and look for
     // strings; there's no portable way to do that.
     GTEST_SKIP()
         << "StrippingTests skipped since this platform is not optimized";
 #endif
   }

   // Opens this program's executable file.  Returns `nullptr` and writes to
   // `stderr` on failure.
   std::unique_ptr<FILE, std::function<void(FILE*)>> OpenTestExecutable() {
 #if defined(__linux__)
     std::unique_ptr<FILE, std::function<void(FILE*)>> fp(
         fopen("/proc/self/exe", "rb"), [](FILE* fp) { fclose(fp); });
     if (!fp) {
       const std::string err = absl::base_internal::StrError(errno);
       absl::FPrintF(stderr, "Failed to open /proc/self/exe: %s\n", err);
     }
     return fp;
 #elif defined(__Fuchsia__)
     // TODO(b/242579714): We need to restore the test coverage on this platform.
     std::unique_ptr<FILE, std::function<void(FILE*)>> fp(
         fopen(absl::StrCat("/pkg/bin/",
                            absl::flags_internal::ShortProgramInvocationName())
                   .c_str(),
               "rb"),
         [](FILE* fp) { fclose(fp); });
     if (!fp) {
       const std::string err = absl::base_internal::StrError(errno);
       absl::FPrintF(stderr, "Failed to open /pkg/bin/<binary name>: %s\n", err);
     }
     return fp;
 #elif defined(__MACH__)
     uint32_t size = 0;
     int ret = _NSGetExecutablePath(nullptr, &size);
     if (ret != -1) {
       absl::FPrintF(stderr,
                     "Failed to get executable path: "
                     "_NSGetExecutablePath(nullptr) returned %d\n",
                     ret);
       return nullptr;
     }
     std::string path(size, '\0');
     ret = _NSGetExecutablePath(&path[0], &size);
     if (ret != 0) {
       absl::FPrintF(
           stderr,
           "Failed to get executable path: _NSGetExecutablePath(buffer) "
           "returned %d\n",
           ret);
       return nullptr;
     }
     std::unique_ptr<FILE, std::function<void(FILE*)>> fp(
         fopen(path.c_str(), "rb"), [](FILE* fp) { fclose(fp); });
     if (!fp) {
       const std::string err = absl::base_internal::StrError(errno);
       absl::FPrintF(stderr, "Failed to open executable at %s: %s\n", path, err);
     }
     return fp;
 #elif defined(_WIN32)
     std::basic_string<TCHAR> path(4096, _T('\0'));
     while (true) {
       const uint32_t ret = ::GetModuleFileName(nullptr, &path[0],
                                                static_cast<DWORD>(path.size()));
       if (ret == 0) {
         absl::FPrintF(
             stderr,
             "Failed to get executable path: GetModuleFileName(buffer) "
             "returned 0\n");
         return nullptr;
       }
       if (ret < path.size()) break;
       path.resize(path.size() * 2, _T('\0'));
     }
     std::unique_ptr<FILE, std::function<void(FILE*)>> fp(
         _tfopen(path.c_str(), _T("rb")), [](FILE* fp) { fclose(fp); });
     if (!fp) absl::FPrintF(stderr, "Failed to open executable\n");
     return fp;
 #else
     absl::FPrintF(stderr,
                   "OpenTestExecutable() unimplemented on this platform\n");
     return nullptr;
 #endif
   }

   ::testing::Matcher<FILE*> FileHasSubstr(absl::string_view needle) {
     return MakeMatcher(new FileHasSubstrMatcher(needle));
   }
 };

 // This tests whether out methodology for testing stripping works on this
 // platform by looking for one string that definitely ought to be there and one
 // that definitely ought not to.  If this fails, none of the `StrippingTest`s
 // are going to produce meaningful results.
 TEST_F(StrippingTest, Control) {
   constexpr char kEncodedPositiveControl[] =
       "U3RyaXBwaW5nVGVzdC5Qb3NpdGl2ZUNvbnRyb2w=";
   const std::string encoded_negative_control =
       absl::Base64Escape("StrippingTest.NegativeControl");

   // Verify this mainly so we can encode other strings and know definitely they
   // won't encode to `kEncodedPositiveControl`.
   EXPECT_THAT(Base64UnescapeOrDie("U3RyaXBwaW5nVGVzdC5Qb3NpdGl2ZUNvbnRyb2w="),
               Eq("StrippingTest.PositiveControl"));

   auto exe = OpenTestExecutable();
   ASSERT_THAT(exe, NotNull());
   EXPECT_THAT(exe.get(), FileHasSubstr(kEncodedPositiveControl));
   EXPECT_THAT(exe.get(), Not(FileHasSubstr(encoded_negative_control)));
 }

 TEST_F(StrippingTest, Literal) {
   // We need to load a copy of the needle string into memory (so we can search
   // for it) without leaving it lying around in plaintext in the executable file
   // as would happen if we used a literal.  We might (or might not) leave it
   // lying around later; that's what the tests are for!
   const std::string needle = absl::Base64Escape("StrippingTest.Literal");
   LOG(INFO) << "U3RyaXBwaW5nVGVzdC5MaXRlcmFs";
   auto exe = OpenTestExecutable();
   ASSERT_THAT(exe, NotNull());
   if (absl::LogSeverity::kInfo >= kAbslMinLogLevel) {
     EXPECT_THAT(exe.get(), FileHasSubstr(needle));
   } else {
     EXPECT_THAT(exe.get(), Not(FileHasSubstr(needle)));
   }
 }

 TEST_F(StrippingTest, LiteralInExpression) {
   // We need to load a copy of the needle string into memory (so we can search
   // for it) without leaving it lying around in plaintext in the executable file
   // as would happen if we used a literal.  We might (or might not) leave it
   // lying around later; that's what the tests are for!
   const std::string needle =
       absl::Base64Escape("StrippingTest.LiteralInExpression");
   LOG(INFO) << absl::StrCat("secret: ",
                             "U3RyaXBwaW5nVGVzdC5MaXRlcmFsSW5FeHByZXNzaW9u");
   std::unique_ptr<FILE, std::function<void(FILE*)>> exe = OpenTestExecutable();
   ASSERT_THAT(exe, NotNull());
   if (absl::LogSeverity::kInfo >= kAbslMinLogLevel) {
     EXPECT_THAT(exe.get(), FileHasSubstr(needle));
   } else {
     EXPECT_THAT(exe.get(), Not(FileHasSubstr(needle)));
   }
 }

 TEST_F(StrippingTest, Fatal) {
   // We need to load a copy of the needle string into memory (so we can search
   // for it) without leaving it lying around in plaintext in the executable file
   // as would happen if we used a literal.  We might (or might not) leave it
   // lying around later; that's what the tests are for!
   const std::string needle = absl::Base64Escape("StrippingTest.Fatal");
   // We don't care if the LOG statement is actually executed, we're just
   // checking that it's stripped.
   if (kReallyDie) LOG(FATAL) << "U3RyaXBwaW5nVGVzdC5GYXRhbA==";

   std::unique_ptr<FILE, std::function<void(FILE*)>> exe = OpenTestExecutable();
   ASSERT_THAT(exe, NotNull());
   if (absl::LogSeverity::kFatal >= kAbslMinLogLevel) {
     EXPECT_THAT(exe.get(), FileHasSubstr(needle));
   } else {
     EXPECT_THAT(exe.get(), Not(FileHasSubstr(needle)));
   }
 }

 TEST_F(StrippingTest, DFatal) {
   // We need to load a copy of the needle string into memory (so we can search
   // for it) without leaving it lying around in plaintext in the executable file
   // as would happen if we used a literal.  We might (or might not) leave it
   // lying around later; that's what the tests are for!
   const std::string needle = absl::Base64Escape("StrippingTest.DFatal");
   // We don't care if the LOG statement is actually executed, we're just
   // checking that it's stripped.
   if (kReallyDie) LOG(DFATAL) << "U3RyaXBwaW5nVGVzdC5ERmF0YWw=";

   std::unique_ptr<FILE, std::function<void(FILE*)>> exe = OpenTestExecutable();
   ASSERT_THAT(exe, NotNull());
   // `DFATAL` can be `ERROR` or `FATAL`, and a compile-time optimizer doesn't
   // know which, because `absl::kLogDebugFatal` is declared `extern` and defined
   // in another TU.  Link-time optimization might do better.  We have six cases:
   // |         `AMLL` is-> | `<=ERROR` | `FATAL` | `>FATAL` |
   // | ------------------- | --------- | ------- | -------- |
   // | `DFATAL` is `ERROR` |   present |       ? | stripped |
   // | `DFATAL` is `FATAL` |   present | present | stripped |

   // These constexpr variables are used to suppress unreachable code warnings
   // in the if-else statements below.

   // "present" in the table above: `DFATAL` exceeds `ABSL_MIN_LOG_LEVEL`, so
   // `DFATAL` statements should not be stripped (and they should be logged
   // when executed, but that's a different testsuite).
   constexpr bool kExpectPresent = absl::kLogDebugFatal >= kAbslMinLogLevel;

   // "stripped" in the table above: even though the compiler may not know
   // which value `DFATAL` has, it should be able to strip it since both
   // possible values ought to be stripped.
   constexpr bool kExpectStripped = kAbslMinLogLevel > absl::LogSeverity::kFatal;

   if (kExpectPresent) {
     EXPECT_THAT(exe.get(), FileHasSubstr(needle));
   } else if (kExpectStripped) {
     EXPECT_THAT(exe.get(), Not(FileHasSubstr(needle)));
   } else {
     // "?" in the table above; may or may not be stripped depending on whether
     // any link-time optimization is done.  Either outcome is ok.
   }
 }

 TEST_F(StrippingTest, Level) {
   const std::string needle = absl::Base64Escape("StrippingTest.Level");
   volatile auto severity = absl::LogSeverity::kWarning;
   // Ensure that `severity` is not a compile-time constant to prove that
   // stripping works regardless:
   LOG(LEVEL(severity)) << "U3RyaXBwaW5nVGVzdC5MZXZlbA==";
   std::unique_ptr<FILE, std::function<void(FILE*)>> exe = OpenTestExecutable();
   ASSERT_THAT(exe, NotNull());
   if (absl::LogSeverity::kFatal >= kAbslMinLogLevel) {
     // This can't be stripped at compile-time because it might evaluate to a
     // level that shouldn't be stripped.
     EXPECT_THAT(exe.get(), FileHasSubstr(needle));
   } else {
 #if (defined(_MSC_VER) && !defined(__clang__)) || defined(__APPLE__)
     // Dead code elimination misses this case.
 #else
     // All levels should be stripped, so it doesn't matter what the severity
     // winds up being.
     EXPECT_THAT(exe.get(), Not(FileHasSubstr(needle)));
 #endif
   }
 }

 TEST_F(StrippingTest, Check) {
   // Here we also need a variable name with enough entropy that it's unlikely to
   // appear in the binary by chance.  `volatile` keeps the tautological
   // comparison (and the rest of the `CHECK`) from being optimized away.
   const std::string var_needle = absl::Base64Escape("StrippingTestCheckVar");
   const std::string msg_needle = absl::Base64Escape("StrippingTest.Check");
   volatile int U3RyaXBwaW5nVGVzdENoZWNrVmFy = 0xCAFE;
   // We don't care if the CHECK is actually executed, just that stripping works.
   // Hiding it behind `kReallyDie` works around some overly aggressive
   // optimizations in older versions of MSVC.
   if (kReallyDie) {
     CHECK(U3RyaXBwaW5nVGVzdENoZWNrVmFy != U3RyaXBwaW5nVGVzdENoZWNrVmFy)
         << "U3RyaXBwaW5nVGVzdC5DaGVjaw==";
   }

   std::unique_ptr<FILE, std::function<void(FILE*)>> exe = OpenTestExecutable();
   ASSERT_THAT(exe, NotNull());
   if (absl::LogSeverity::kFatal >= kAbslMinLogLevel) {
     EXPECT_THAT(exe.get(), FileHasSubstr(var_needle));
     EXPECT_THAT(exe.get(), FileHasSubstr(msg_needle));
   } else {
     EXPECT_THAT(exe.get(), Not(FileHasSubstr(var_needle)));
     EXPECT_THAT(exe.get(), Not(FileHasSubstr(msg_needle)));
   }
 }

 TEST_F(StrippingTest, CheckOp) {
   // See `StrippingTest.Check` for some hairy implementation notes.
   const std::string var_needle1 =
       absl::Base64Escape("StrippingTestCheckOpVar1");
   const std::string var_needle2 =
       absl::Base64Escape("StrippingTestCheckOpVar2");
   const std::string msg_needle = absl::Base64Escape("StrippingTest.CheckOp");
   volatile int U3RyaXBwaW5nVGVzdENoZWNrT3BWYXIx = 0xFEED;
   volatile int U3RyaXBwaW5nVGVzdENoZWNrT3BWYXIy = 0xCAFE;
   if (kReallyDie) {
     CHECK_EQ(U3RyaXBwaW5nVGVzdENoZWNrT3BWYXIx, U3RyaXBwaW5nVGVzdENoZWNrT3BWYXIy)
         << "U3RyaXBwaW5nVGVzdC5DaGVja09w";
   }

   std::unique_ptr<FILE, std::function<void(FILE*)>> exe = OpenTestExecutable();
   ASSERT_THAT(exe, NotNull());

   if (absl::LogSeverity::kFatal >= kAbslMinLogLevel) {
     EXPECT_THAT(exe.get(), FileHasSubstr(var_needle1));
     EXPECT_THAT(exe.get(), FileHasSubstr(var_needle2));
     EXPECT_THAT(exe.get(), FileHasSubstr(msg_needle));
   } else {
     EXPECT_THAT(exe.get(), Not(FileHasSubstr(var_needle1)));
     EXPECT_THAT(exe.get(), Not(FileHasSubstr(var_needle2)));
     EXPECT_THAT(exe.get(), Not(FileHasSubstr(msg_needle)));
   }
 }

 TEST_F(StrippingTest, CheckStrOp) {
   // See `StrippingTest.Check` for some hairy implementation notes.
   const std::string var_needle1 =
       absl::Base64Escape("StrippingTestCheckStrOpVar1");
   const std::string var_needle2 =
       absl::Base64Escape("StrippingTestCheckStrOpVar2");
   const std::string msg_needle = absl::Base64Escape("StrippingTest.CheckStrOp");
   const char *volatile U3RyaXBwaW5nVGVzdENoZWNrU3RyT3BWYXIx = "FEED";
   const char *volatile U3RyaXBwaW5nVGVzdENoZWNrU3RyT3BWYXIy = "CAFE";
   if (kReallyDie) {
     CHECK_STREQ(U3RyaXBwaW5nVGVzdENoZWNrU3RyT3BWYXIx,
                 U3RyaXBwaW5nVGVzdENoZWNrU3RyT3BWYXIy)
         << "U3RyaXBwaW5nVGVzdC5DaGVja1N0ck9w";
   }

   std::unique_ptr<FILE, std::function<void(FILE*)>> exe = OpenTestExecutable();
   ASSERT_THAT(exe, NotNull());

   if (absl::LogSeverity::kFatal >= kAbslMinLogLevel) {
     EXPECT_THAT(exe.get(), FileHasSubstr(var_needle1));
     EXPECT_THAT(exe.get(), FileHasSubstr(var_needle2));
     EXPECT_THAT(exe.get(), FileHasSubstr(msg_needle));
   } else {
     EXPECT_THAT(exe.get(), Not(FileHasSubstr(var_needle1)));
     EXPECT_THAT(exe.get(), Not(FileHasSubstr(var_needle2)));
     EXPECT_THAT(exe.get(), Not(FileHasSubstr(msg_needle)));
   }
 }

 TEST_F(StrippingTest, CheckOk) {
   // See `StrippingTest.Check` for some hairy implementation notes.
   const std::string var_needle = absl::Base64Escape("StrippingTestCheckOkVar1");
   const std::string msg_needle = absl::Base64Escape("StrippingTest.CheckOk");
   volatile bool x = false;
   auto U3RyaXBwaW5nVGVzdENoZWNrT2tWYXIx = absl::OkStatus();
   if (x) {
     U3RyaXBwaW5nVGVzdENoZWNrT2tWYXIx =
         absl::InvalidArgumentError("Stripping this is not my job!");
   }
   if (kReallyDie) {
     CHECK_OK(U3RyaXBwaW5nVGVzdENoZWNrT2tWYXIx)
         << "U3RyaXBwaW5nVGVzdC5DaGVja09r";
   }

   std::unique_ptr<FILE, std::function<void(FILE*)>> exe = OpenTestExecutable();
   ASSERT_THAT(exe, NotNull());

   if (absl::LogSeverity::kFatal >= kAbslMinLogLevel) {
     EXPECT_THAT(exe.get(), FileHasSubstr(var_needle));
     EXPECT_THAT(exe.get(), FileHasSubstr(msg_needle));
   } else {
     EXPECT_THAT(exe.get(), Not(FileHasSubstr(var_needle)));
     EXPECT_THAT(exe.get(), Not(FileHasSubstr(msg_needle)));
   }
 }

 }  // namespace
	//
	// Copyright 2022 The Abseil Authors.
	//
	// 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
	//
	// https://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.
	//
	// Tests for stripping of literal strings.
	// ---------------------------------------
	//
	// When a `LOG` statement can be trivially proved at compile time to never fire,
	// e.g. due to `ABSL_MIN_LOG_LEVEL`, `NDEBUG`, or some explicit condition, data
	// streamed in can be dropped from the compiled program completely if they are
	// not used elsewhere. This most commonly affects string literals, which users
	// often want to strip to reduce binary size and/or redact information about
	// their program's internals (e.g. in a release build).
	//
	// These tests log strings and then validate whether they appear in the compiled
	// binary. This is done by opening the file corresponding to the running test
	// and running a simple string search on its contents. The strings to be logged
	// and searched for must be unique, and we must take care not to emit them into
	// the binary in any other place, e.g. when searching for them. The latter is
	// accomplished by computing them using base64; the source string appears in the
	// binary but the target string is computed at runtime.

	#include <stdio.h>

	#if defined(__MACH__)
	#include <mach-o/dyld.h>
	#elif defined(_WIN32)
	#include <Windows.h>
	#include <tchar.h>
	#endif

	#include <algorithm>
	#include <functional>
	#include <memory>
	#include <ostream>
	#include <string>

	#include "gmock/gmock.h"
	#include "gtest/gtest.h"
	#include "absl/base/internal/strerror.h"
	#include "absl/base/log_severity.h"
	#include "absl/flags/internal/program_name.h"
	#include "absl/log/check.h"
	#include "absl/log/internal/test_helpers.h"
	#include "absl/log/log.h"
	#include "absl/status/status.h"
	#include "absl/strings/escaping.h"
	#include "absl/strings/str_format.h"
	#include "absl/strings/string_view.h"

	// Set a flag that controls whether we actually execute fatal statements, but
	// prevent the compiler from optimizing it out.
	static volatile bool kReallyDie = false;

	namespace {
	using ::testing::_;
	using ::testing::Eq;
	using ::testing::NotNull;

	using absl::log_internal::kAbslMinLogLevel;

	std::string Base64UnescapeOrDie(absl::string_view data) {
	std::string decoded;
	CHECK(absl::Base64Unescape(data, &decoded));
	return decoded;
	}

	// -----------------------------------------------------------------------------
	// A Googletest matcher which searches the running binary for a given string
	// -----------------------------------------------------------------------------

	// This matcher is used to validate that literal strings streamed into
	// `LOG` statements that ought to be compiled out (e.g. `LOG_IF(INFO, false)`)
	// do not appear in the binary.
	//
	// Note that passing the string to be sought directly to `FileHasSubstr()` all
	// but forces its inclusion in the binary regardless of the logging library's
	// behavior. For example:
	//
	// LOG_IF(INFO, false) << "you're the man now dog";
	// // This will always pass:
	// // EXPECT_THAT(fp, FileHasSubstr("you're the man now dog"));
	// // So use this instead:
	// EXPECT_THAT(fp, FileHasSubstr(
	// Base64UnescapeOrDie("eW91J3JlIHRoZSBtYW4gbm93IGRvZw==")));

	class FileHasSubstrMatcher final : public ::testing::MatcherInterface<FILE*> {
	public:
	explicit FileHasSubstrMatcher(absl::string_view needle) : needle_(needle) {}

	bool MatchAndExplain(
	FILE* fp, ::testing::MatchResultListener* listener) const override {
	std::string buf(
	std::max<std::string::size_type>(needle_.size() * 2, 163840000), '\0');
	size_t buf_start_offset = 0; // The file offset of the byte at `buf[0]`.
	size_t buf_data_size = 0; // The number of bytes of `buf` which contain
	// data.

	::fseek(fp, 0, SEEK_SET);
	while (true) {
	// Fill the buffer to capacity or EOF:
	while (buf_data_size < buf.size()) {
	const size_t ret = fread(&buf[buf_data_size], sizeof(char),
	buf.size() - buf_data_size, fp);
	if (ret == 0) break;
	buf_data_size += ret;
	}
	if (ferror(fp)) {
	*listener << "error reading file";
	return false;
	}
	const absl::string_view haystack(&buf[0], buf_data_size);
	const auto off = haystack.find(needle_);
	if (off != haystack.npos) {
	*listener << "string found at offset " << buf_start_offset + off;
	return true;
	}
	if (feof(fp)) {
	*listener << "string not found";
	return false;
	}
	// Copy the end of `buf` to the beginning so we catch matches that span
	// buffer boundaries. `buf` and `buf_data_size` are always large enough
	// that these ranges don't overlap.
	memcpy(&buf[0], &buf[buf_data_size - needle_.size()], needle_.size());
	buf_start_offset += buf_data_size - needle_.size();
	buf_data_size = needle_.size();
	}
	}
	void DescribeTo(std::ostream* os) const override {
	*os << "contains the string \"" << needle_ << "\" (base64(\""
	<< Base64UnescapeOrDie(needle_) << "\"))";
	}

	void DescribeNegationTo(std::ostream* os) const override {
	*os << "does not ";
	DescribeTo(os);
	}

	private:
	std::string needle_;
	};

	class StrippingTest : public ::testing::Test {
	protected:
	void SetUp() override {
	#ifndef NDEBUG
	// Non-optimized builds don't necessarily eliminate dead code at all, so we
	// don't attempt to validate stripping against such builds.
	GTEST_SKIP() << "StrippingTests skipped since this build is not optimized";
	#elif defined(__EMSCRIPTEN__)
	// These tests require a way to examine the running binary and look for
	// strings; there's no portable way to do that.
	GTEST_SKIP()
	<< "StrippingTests skipped since this platform is not optimized";
	#endif
	}

	// Opens this program's executable file. Returns `nullptr` and writes to
	// `stderr` on failure.
	std::unique_ptr<FILE, std::function<void(FILE*)>> OpenTestExecutable() {
	#if defined(__linux__)
	std::unique_ptr<FILE, std::function<void(FILE*)>> fp(
	fopen("/proc/self/exe", "rb"), [](FILE* fp) { fclose(fp); });
	if (!fp) {
	const std::string err = absl::base_internal::StrError(errno);
	absl::FPrintF(stderr, "Failed to open /proc/self/exe: %s\n", err);
	}
	return fp;
	#elif defined(__Fuchsia__)
	// TODO(b/242579714): We need to restore the test coverage on this platform.
	std::unique_ptr<FILE, std::function<void(FILE*)>> fp(
	fopen(absl::StrCat("/pkg/bin/",
	absl::flags_internal::ShortProgramInvocationName())
	.c_str(),
	"rb"),
	[](FILE* fp) { fclose(fp); });
	if (!fp) {
	const std::string err = absl::base_internal::StrError(errno);
	absl::FPrintF(stderr, "Failed to open /pkg/bin/<binary name>: %s\n", err);
	}
	return fp;
	#elif defined(__MACH__)
	uint32_t size = 0;
	int ret = _NSGetExecutablePath(nullptr, &size);
	if (ret != -1) {
	absl::FPrintF(stderr,
	"Failed to get executable path: "
	"_NSGetExecutablePath(nullptr) returned %d\n",
	ret);
	return nullptr;
	}
	std::string path(size, '\0');
	ret = _NSGetExecutablePath(&path[0], &size);
	if (ret != 0) {
	absl::FPrintF(
	stderr,
	"Failed to get executable path: _NSGetExecutablePath(buffer) "
	"returned %d\n",
	ret);
	return nullptr;
	}
	std::unique_ptr<FILE, std::function<void(FILE*)>> fp(
	fopen(path.c_str(), "rb"), [](FILE* fp) { fclose(fp); });
	if (!fp) {
	const std::string err = absl::base_internal::StrError(errno);
	absl::FPrintF(stderr, "Failed to open executable at %s: %s\n", path, err);
	}
	return fp;
	#elif defined(_WIN32)
	std::basic_string<TCHAR> path(4096, _T('\0'));
	while (true) {
	const uint32_t ret = ::GetModuleFileName(nullptr, &path[0],
	static_cast<DWORD>(path.size()));
	if (ret == 0) {
	absl::FPrintF(
	stderr,
	"Failed to get executable path: GetModuleFileName(buffer) "
	"returned 0\n");
	return nullptr;
	}
	if (ret < path.size()) break;
	path.resize(path.size() * 2, _T('\0'));
	}
	std::unique_ptr<FILE, std::function<void(FILE*)>> fp(
	_tfopen(path.c_str(), _T("rb")), [](FILE* fp) { fclose(fp); });
	if (!fp) absl::FPrintF(stderr, "Failed to open executable\n");
	return fp;
	#else
	absl::FPrintF(stderr,
	"OpenTestExecutable() unimplemented on this platform\n");
	return nullptr;
	#endif
	}

	::testing::Matcher<FILE*> FileHasSubstr(absl::string_view needle) {
	return MakeMatcher(new FileHasSubstrMatcher(needle));
	}
	};

	// This tests whether out methodology for testing stripping works on this
	// platform by looking for one string that definitely ought to be there and one
	// that definitely ought not to. If this fails, none of the `StrippingTest`s
	// are going to produce meaningful results.
	TEST_F(StrippingTest, Control) {
	constexpr char kEncodedPositiveControl[] =
	"U3RyaXBwaW5nVGVzdC5Qb3NpdGl2ZUNvbnRyb2w=";
	const std::string encoded_negative_control =
	absl::Base64Escape("StrippingTest.NegativeControl");

	// Verify this mainly so we can encode other strings and know definitely they
	// won't encode to `kEncodedPositiveControl`.
	EXPECT_THAT(Base64UnescapeOrDie("U3RyaXBwaW5nVGVzdC5Qb3NpdGl2ZUNvbnRyb2w="),
	Eq("StrippingTest.PositiveControl"));

	auto exe = OpenTestExecutable();
	ASSERT_THAT(exe, NotNull());
	EXPECT_THAT(exe.get(), FileHasSubstr(kEncodedPositiveControl));
	EXPECT_THAT(exe.get(), Not(FileHasSubstr(encoded_negative_control)));
	}

	TEST_F(StrippingTest, Literal) {
	// We need to load a copy of the needle string into memory (so we can search
	// for it) without leaving it lying around in plaintext in the executable file
	// as would happen if we used a literal. We might (or might not) leave it
	// lying around later; that's what the tests are for!
	const std::string needle = absl::Base64Escape("StrippingTest.Literal");
	LOG(INFO) << "U3RyaXBwaW5nVGVzdC5MaXRlcmFs";
	auto exe = OpenTestExecutable();
	ASSERT_THAT(exe, NotNull());
	if (absl::LogSeverity::kInfo >= kAbslMinLogLevel) {
	EXPECT_THAT(exe.get(), FileHasSubstr(needle));
	} else {
	EXPECT_THAT(exe.get(), Not(FileHasSubstr(needle)));
	}
	}

	TEST_F(StrippingTest, LiteralInExpression) {
	// We need to load a copy of the needle string into memory (so we can search
	// for it) without leaving it lying around in plaintext in the executable file
	// as would happen if we used a literal. We might (or might not) leave it
	// lying around later; that's what the tests are for!
	const std::string needle =
	absl::Base64Escape("StrippingTest.LiteralInExpression");
	LOG(INFO) << absl::StrCat("secret: ",
	"U3RyaXBwaW5nVGVzdC5MaXRlcmFsSW5FeHByZXNzaW9u");
	std::unique_ptr<FILE, std::function<void(FILE*)>> exe = OpenTestExecutable();
	ASSERT_THAT(exe, NotNull());
	if (absl::LogSeverity::kInfo >= kAbslMinLogLevel) {
	EXPECT_THAT(exe.get(), FileHasSubstr(needle));
	} else {
	EXPECT_THAT(exe.get(), Not(FileHasSubstr(needle)));
	}
	}

	TEST_F(StrippingTest, Fatal) {
	// We need to load a copy of the needle string into memory (so we can search
	// for it) without leaving it lying around in plaintext in the executable file
	// as would happen if we used a literal. We might (or might not) leave it
	// lying around later; that's what the tests are for!
	const std::string needle = absl::Base64Escape("StrippingTest.Fatal");
	// We don't care if the LOG statement is actually executed, we're just
	// checking that it's stripped.
	if (kReallyDie) LOG(FATAL) << "U3RyaXBwaW5nVGVzdC5GYXRhbA==";

	std::unique_ptr<FILE, std::function<void(FILE*)>> exe = OpenTestExecutable();
	ASSERT_THAT(exe, NotNull());
	if (absl::LogSeverity::kFatal >= kAbslMinLogLevel) {
	EXPECT_THAT(exe.get(), FileHasSubstr(needle));
	} else {
	EXPECT_THAT(exe.get(), Not(FileHasSubstr(needle)));
	}
	}

	TEST_F(StrippingTest, DFatal) {
	// We need to load a copy of the needle string into memory (so we can search
	// for it) without leaving it lying around in plaintext in the executable file
	// as would happen if we used a literal. We might (or might not) leave it
	// lying around later; that's what the tests are for!
	const std::string needle = absl::Base64Escape("StrippingTest.DFatal");
	// We don't care if the LOG statement is actually executed, we're just
	// checking that it's stripped.
	if (kReallyDie) LOG(DFATAL) << "U3RyaXBwaW5nVGVzdC5ERmF0YWw=";

	std::unique_ptr<FILE, std::function<void(FILE*)>> exe = OpenTestExecutable();
	ASSERT_THAT(exe, NotNull());
	// `DFATAL` can be `ERROR` or `FATAL`, and a compile-time optimizer doesn't
	// know which, because `absl::kLogDebugFatal` is declared `extern` and defined
	// in another TU. Link-time optimization might do better. We have six cases:
	// \| `AMLL` is-> \| `<=ERROR` \| `FATAL` \| `>FATAL` \|
	// \| ------------------- \| --------- \| ------- \| -------- \|
	// \| `DFATAL` is `ERROR` \| present \| ? \| stripped \|
	// \| `DFATAL` is `FATAL` \| present \| present \| stripped \|

	// These constexpr variables are used to suppress unreachable code warnings
	// in the if-else statements below.

	// "present" in the table above: `DFATAL` exceeds `ABSL_MIN_LOG_LEVEL`, so
	// `DFATAL` statements should not be stripped (and they should be logged
	// when executed, but that's a different testsuite).
	constexpr bool kExpectPresent = absl::kLogDebugFatal >= kAbslMinLogLevel;

	// "stripped" in the table above: even though the compiler may not know
	// which value `DFATAL` has, it should be able to strip it since both
	// possible values ought to be stripped.
	constexpr bool kExpectStripped = kAbslMinLogLevel > absl::LogSeverity::kFatal;

	if (kExpectPresent) {
	EXPECT_THAT(exe.get(), FileHasSubstr(needle));
	} else if (kExpectStripped) {
	EXPECT_THAT(exe.get(), Not(FileHasSubstr(needle)));
	} else {
	// "?" in the table above; may or may not be stripped depending on whether
	// any link-time optimization is done. Either outcome is ok.
	}
	}

	TEST_F(StrippingTest, Level) {
	const std::string needle = absl::Base64Escape("StrippingTest.Level");
	volatile auto severity = absl::LogSeverity::kWarning;
	// Ensure that `severity` is not a compile-time constant to prove that
	// stripping works regardless:
	LOG(LEVEL(severity)) << "U3RyaXBwaW5nVGVzdC5MZXZlbA==";
	std::unique_ptr<FILE, std::function<void(FILE*)>> exe = OpenTestExecutable();
	ASSERT_THAT(exe, NotNull());
	if (absl::LogSeverity::kFatal >= kAbslMinLogLevel) {
	// This can't be stripped at compile-time because it might evaluate to a
	// level that shouldn't be stripped.
	EXPECT_THAT(exe.get(), FileHasSubstr(needle));
	} else {
	#if (defined(_MSC_VER) && !defined(__clang__)) \|\| defined(__APPLE__)
	// Dead code elimination misses this case.
	#else
	// All levels should be stripped, so it doesn't matter what the severity
	// winds up being.
	EXPECT_THAT(exe.get(), Not(FileHasSubstr(needle)));
	#endif
	}
	}

	TEST_F(StrippingTest, Check) {
	// Here we also need a variable name with enough entropy that it's unlikely to
	// appear in the binary by chance. `volatile` keeps the tautological
	// comparison (and the rest of the `CHECK`) from being optimized away.
	const std::string var_needle = absl::Base64Escape("StrippingTestCheckVar");
	const std::string msg_needle = absl::Base64Escape("StrippingTest.Check");
	volatile int U3RyaXBwaW5nVGVzdENoZWNrVmFy = 0xCAFE;
	// We don't care if the CHECK is actually executed, just that stripping works.
	// Hiding it behind `kReallyDie` works around some overly aggressive
	// optimizations in older versions of MSVC.
	if (kReallyDie) {
	CHECK(U3RyaXBwaW5nVGVzdENoZWNrVmFy != U3RyaXBwaW5nVGVzdENoZWNrVmFy)
	<< "U3RyaXBwaW5nVGVzdC5DaGVjaw==";
	}

	std::unique_ptr<FILE, std::function<void(FILE*)>> exe = OpenTestExecutable();
	ASSERT_THAT(exe, NotNull());
	if (absl::LogSeverity::kFatal >= kAbslMinLogLevel) {
	EXPECT_THAT(exe.get(), FileHasSubstr(var_needle));
	EXPECT_THAT(exe.get(), FileHasSubstr(msg_needle));
	} else {
	EXPECT_THAT(exe.get(), Not(FileHasSubstr(var_needle)));
	EXPECT_THAT(exe.get(), Not(FileHasSubstr(msg_needle)));
	}
	}

	TEST_F(StrippingTest, CheckOp) {
	// See `StrippingTest.Check` for some hairy implementation notes.
	const std::string var_needle1 =
	absl::Base64Escape("StrippingTestCheckOpVar1");
	const std::string var_needle2 =
	absl::Base64Escape("StrippingTestCheckOpVar2");
	const std::string msg_needle = absl::Base64Escape("StrippingTest.CheckOp");
	volatile int U3RyaXBwaW5nVGVzdENoZWNrT3BWYXIx = 0xFEED;
	volatile int U3RyaXBwaW5nVGVzdENoZWNrT3BWYXIy = 0xCAFE;
	if (kReallyDie) {
	CHECK_EQ(U3RyaXBwaW5nVGVzdENoZWNrT3BWYXIx, U3RyaXBwaW5nVGVzdENoZWNrT3BWYXIy)
	<< "U3RyaXBwaW5nVGVzdC5DaGVja09w";
	}

	std::unique_ptr<FILE, std::function<void(FILE*)>> exe = OpenTestExecutable();
	ASSERT_THAT(exe, NotNull());

	if (absl::LogSeverity::kFatal >= kAbslMinLogLevel) {
	EXPECT_THAT(exe.get(), FileHasSubstr(var_needle1));
	EXPECT_THAT(exe.get(), FileHasSubstr(var_needle2));
	EXPECT_THAT(exe.get(), FileHasSubstr(msg_needle));
	} else {
	EXPECT_THAT(exe.get(), Not(FileHasSubstr(var_needle1)));
	EXPECT_THAT(exe.get(), Not(FileHasSubstr(var_needle2)));
	EXPECT_THAT(exe.get(), Not(FileHasSubstr(msg_needle)));
	}
	}

	TEST_F(StrippingTest, CheckStrOp) {
	// See `StrippingTest.Check` for some hairy implementation notes.
	const std::string var_needle1 =
	absl::Base64Escape("StrippingTestCheckStrOpVar1");
	const std::string var_needle2 =
	absl::Base64Escape("StrippingTestCheckStrOpVar2");
	const std::string msg_needle = absl::Base64Escape("StrippingTest.CheckStrOp");
	const char *volatile U3RyaXBwaW5nVGVzdENoZWNrU3RyT3BWYXIx = "FEED";
	const char *volatile U3RyaXBwaW5nVGVzdENoZWNrU3RyT3BWYXIy = "CAFE";
	if (kReallyDie) {
	CHECK_STREQ(U3RyaXBwaW5nVGVzdENoZWNrU3RyT3BWYXIx,
	U3RyaXBwaW5nVGVzdENoZWNrU3RyT3BWYXIy)
	<< "U3RyaXBwaW5nVGVzdC5DaGVja1N0ck9w";
	}

	std::unique_ptr<FILE, std::function<void(FILE*)>> exe = OpenTestExecutable();
	ASSERT_THAT(exe, NotNull());

	if (absl::LogSeverity::kFatal >= kAbslMinLogLevel) {
	EXPECT_THAT(exe.get(), FileHasSubstr(var_needle1));
	EXPECT_THAT(exe.get(), FileHasSubstr(var_needle2));
	EXPECT_THAT(exe.get(), FileHasSubstr(msg_needle));
	} else {
	EXPECT_THAT(exe.get(), Not(FileHasSubstr(var_needle1)));
	EXPECT_THAT(exe.get(), Not(FileHasSubstr(var_needle2)));
	EXPECT_THAT(exe.get(), Not(FileHasSubstr(msg_needle)));
	}
	}

	TEST_F(StrippingTest, CheckOk) {
	// See `StrippingTest.Check` for some hairy implementation notes.
	const std::string var_needle = absl::Base64Escape("StrippingTestCheckOkVar1");
	const std::string msg_needle = absl::Base64Escape("StrippingTest.CheckOk");
	volatile bool x = false;
	auto U3RyaXBwaW5nVGVzdENoZWNrT2tWYXIx = absl::OkStatus();
	if (x) {
	U3RyaXBwaW5nVGVzdENoZWNrT2tWYXIx =
	absl::InvalidArgumentError("Stripping this is not my job!");
	}
	if (kReallyDie) {
	CHECK_OK(U3RyaXBwaW5nVGVzdENoZWNrT2tWYXIx)
	<< "U3RyaXBwaW5nVGVzdC5DaGVja09r";
	}

	std::unique_ptr<FILE, std::function<void(FILE*)>> exe = OpenTestExecutable();
	ASSERT_THAT(exe, NotNull());

	if (absl::LogSeverity::kFatal >= kAbslMinLogLevel) {
	EXPECT_THAT(exe.get(), FileHasSubstr(var_needle));
	EXPECT_THAT(exe.get(), FileHasSubstr(msg_needle));
	} else {
	EXPECT_THAT(exe.get(), Not(FileHasSubstr(var_needle)));
	EXPECT_THAT(exe.get(), Not(FileHasSubstr(msg_needle)));
	}
	}

	} // namespace