143 lines
4.5 KiB
C++
143 lines
4.5 KiB
C++
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// Copyright 2018 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include <fcntl.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <unistd.h>
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#include <string>
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#include "gmock/gmock.h"
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#include "gtest/gtest.h"
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#include "gtest/gtest.h"
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#include "test/util/file_descriptor.h"
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#include "test/util/logging.h"
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#include "test/util/memory_util.h"
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#include "test/util/posix_error.h"
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#include "test/util/temp_path.h"
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#include "test/util/test_util.h"
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namespace gvisor {
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namespace testing {
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namespace {
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void ExpectAllMappingBytes(Mapping const& m, char c) {
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auto const v = m.view();
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for (size_t i = 0; i < kPageSize; i++) {
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ASSERT_EQ(v[i], c) << "at offset " << i;
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}
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}
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// Equivalent to ExpectAllMappingBytes but async-signal-safe and with less
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// helpful failure messages.
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void CheckAllMappingBytes(Mapping const& m, char c) {
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auto const v = m.view();
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for (size_t i = 0; i < kPageSize; i++) {
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TEST_CHECK_MSG(v[i] == c, "mapping contains wrong value");
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}
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}
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TEST(MadviseDontneedTest, ZerosPrivateAnonPage) {
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auto m = ASSERT_NO_ERRNO_AND_VALUE(
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MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE));
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ExpectAllMappingBytes(m, 0);
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memset(m.ptr(), 1, m.len());
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ExpectAllMappingBytes(m, 1);
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ASSERT_THAT(madvise(m.ptr(), m.len(), MADV_DONTNEED), SyscallSucceeds());
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ExpectAllMappingBytes(m, 0);
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}
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TEST(MadviseDontneedTest, ZerosCOWAnonPageInCallerOnly) {
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auto m = ASSERT_NO_ERRNO_AND_VALUE(
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MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE));
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ExpectAllMappingBytes(m, 0);
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memset(m.ptr(), 2, m.len());
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ExpectAllMappingBytes(m, 2);
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// Do madvise in a child process.
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pid_t pid = fork();
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CheckAllMappingBytes(m, 2);
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if (pid == 0) {
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TEST_PCHECK(madvise(m.ptr(), m.len(), MADV_DONTNEED) == 0);
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CheckAllMappingBytes(m, 0);
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_exit(0);
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}
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ASSERT_THAT(pid, SyscallSucceeds());
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int status = 0;
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ASSERT_THAT(waitpid(-1, &status, 0), SyscallSucceedsWithValue(pid));
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EXPECT_TRUE(WIFEXITED(status));
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EXPECT_EQ(WEXITSTATUS(status), 0);
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// The child's madvise should not have affected the parent.
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ExpectAllMappingBytes(m, 2);
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}
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TEST(MadviseDontneedTest, DoesNotModifySharedAnonPage) {
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auto m = ASSERT_NO_ERRNO_AND_VALUE(
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MmapAnon(kPageSize, PROT_READ | PROT_WRITE, MAP_SHARED));
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ExpectAllMappingBytes(m, 0);
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memset(m.ptr(), 3, m.len());
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ExpectAllMappingBytes(m, 3);
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ASSERT_THAT(madvise(m.ptr(), m.len(), MADV_DONTNEED), SyscallSucceeds());
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ExpectAllMappingBytes(m, 3);
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}
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TEST(MadviseDontneedTest, CleansPrivateFilePage) {
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TempPath f = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
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/* parent = */ GetAbsoluteTestTmpdir(),
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/* content = */ std::string(kPageSize, 4), TempPath::kDefaultFileMode));
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FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(f.path(), O_RDWR));
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Mapping m = ASSERT_NO_ERRNO_AND_VALUE(Mmap(
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nullptr, kPageSize, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd.get(), 0));
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ExpectAllMappingBytes(m, 4);
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memset(m.ptr(), 5, m.len());
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ExpectAllMappingBytes(m, 5);
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ASSERT_THAT(madvise(m.ptr(), m.len(), MADV_DONTNEED), SyscallSucceeds());
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ExpectAllMappingBytes(m, 4);
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}
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TEST(MadviseDontneedTest, DoesNotModifySharedFilePage) {
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TempPath f = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
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/* parent = */ GetAbsoluteTestTmpdir(),
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/* content = */ std::string(kPageSize, 6), TempPath::kDefaultFileMode));
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FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(f.path(), O_RDWR));
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Mapping m = ASSERT_NO_ERRNO_AND_VALUE(Mmap(
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nullptr, kPageSize, PROT_READ | PROT_WRITE, MAP_SHARED, fd.get(), 0));
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ExpectAllMappingBytes(m, 6);
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memset(m.ptr(), 7, m.len());
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ExpectAllMappingBytes(m, 7);
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ASSERT_THAT(madvise(m.ptr(), m.len(), MADV_DONTNEED), SyscallSucceeds());
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ExpectAllMappingBytes(m, 7);
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}
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TEST(MadviseDontneedTest, IgnoresPermissions) {
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auto m =
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ASSERT_NO_ERRNO_AND_VALUE(MmapAnon(kPageSize, PROT_NONE, MAP_PRIVATE));
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EXPECT_THAT(madvise(m.ptr(), m.len(), MADV_DONTNEED), SyscallSucceeds());
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}
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} // namespace
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} // namespace testing
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} // namespace gvisor
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