// Copyright 2018 The gVisor 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 // // 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 <fcntl.h> #include <signal.h> #include <sys/types.h> #include <syscall.h> #include <unistd.h> #include <string> #include "gtest/gtest.h" #include "absl/base/macros.h" #include "absl/base/port.h" #include "absl/flags/flag.h" #include "absl/memory/memory.h" #include "absl/strings/str_cat.h" #include "absl/time/clock.h" #include "absl/time/time.h" #include "test/syscalls/linux/socket_test_util.h" #include "test/util/cleanup.h" #include "test/util/eventfd_util.h" #include "test/util/fs_util.h" #include "test/util/multiprocess_util.h" #include "test/util/posix_error.h" #include "test/util/save_util.h" #include "test/util/temp_path.h" #include "test/util/test_util.h" #include "test/util/timer_util.h" ABSL_FLAG(std::string, child_setlock_on, "", "Contains the path to try to set a file lock on."); ABSL_FLAG(bool, child_setlock_write, false, "Whether to set a writable lock (otherwise readable)"); ABSL_FLAG(bool, blocking, false, "Whether to set a blocking lock (otherwise non-blocking)."); ABSL_FLAG(bool, retry_eintr, false, "Whether to retry in the subprocess on EINTR."); ABSL_FLAG(uint64_t, child_setlock_start, 0, "The value of struct flock start"); ABSL_FLAG(uint64_t, child_setlock_len, 0, "The value of struct flock len"); ABSL_FLAG(int32_t, socket_fd, -1, "A socket to use for communicating more state back " "to the parent."); namespace gvisor { namespace testing { class FcntlLockTest : public ::testing::Test { public: void SetUp() override { // Let's make a socket pair. ASSERT_THAT(socketpair(AF_UNIX, SOCK_STREAM, 0, fds_), SyscallSucceeds()); } void TearDown() override { EXPECT_THAT(close(fds_[0]), SyscallSucceeds()); EXPECT_THAT(close(fds_[1]), SyscallSucceeds()); } int64_t GetSubprocessFcntlTimeInUsec() { int64_t ret = 0; EXPECT_THAT(ReadFd(fds_[0], reinterpret_cast<void*>(&ret), sizeof(ret)), SyscallSucceedsWithValue(sizeof(ret))); return ret; } // The first fd will remain with the process creating the subprocess // and the second will go to the subprocess. int fds_[2] = {}; }; namespace { PosixErrorOr<Cleanup> SubprocessLock(std::string const& path, bool for_write, bool blocking, bool retry_eintr, int fd, off_t start, off_t length, pid_t* child) { std::vector<std::string> args = { "/proc/self/exe", "--child_setlock_on", path, "--child_setlock_start", absl::StrCat(start), "--child_setlock_len", absl::StrCat(length), "--socket_fd", absl::StrCat(fd)}; if (for_write) { args.push_back("--child_setlock_write"); } if (blocking) { args.push_back("--blocking"); } if (retry_eintr) { args.push_back("--retry_eintr"); } int execve_errno = 0; ASSIGN_OR_RETURN_ERRNO( auto cleanup, ForkAndExec("/proc/self/exe", ExecveArray(args.begin(), args.end()), {}, nullptr, child, &execve_errno)); if (execve_errno != 0) { return PosixError(execve_errno, "execve"); } return std::move(cleanup); } TEST(FcntlTest, SetCloExec) { // Open an eventfd file descriptor with FD_CLOEXEC descriptor flag not set. FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(NewEventFD(0, 0)); ASSERT_THAT(fcntl(fd.get(), F_GETFD), SyscallSucceedsWithValue(0)); // Set the FD_CLOEXEC flag. ASSERT_THAT(fcntl(fd.get(), F_SETFD, FD_CLOEXEC), SyscallSucceeds()); ASSERT_THAT(fcntl(fd.get(), F_GETFD), SyscallSucceedsWithValue(FD_CLOEXEC)); } TEST(FcntlTest, ClearCloExec) { // Open an eventfd file descriptor with FD_CLOEXEC descriptor flag set. FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(NewEventFD(0, EFD_CLOEXEC)); ASSERT_THAT(fcntl(fd.get(), F_GETFD), SyscallSucceedsWithValue(FD_CLOEXEC)); // Clear the FD_CLOEXEC flag. ASSERT_THAT(fcntl(fd.get(), F_SETFD, 0), SyscallSucceeds()); ASSERT_THAT(fcntl(fd.get(), F_GETFD), SyscallSucceedsWithValue(0)); } TEST(FcntlTest, IndependentDescriptorFlags) { // Open an eventfd file descriptor with FD_CLOEXEC descriptor flag not set. FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(NewEventFD(0, 0)); ASSERT_THAT(fcntl(fd.get(), F_GETFD), SyscallSucceedsWithValue(0)); // Duplicate the descriptor. Ensure that it also doesn't have FD_CLOEXEC. FileDescriptor newfd = ASSERT_NO_ERRNO_AND_VALUE(fd.Dup()); ASSERT_THAT(fcntl(newfd.get(), F_GETFD), SyscallSucceedsWithValue(0)); // Set FD_CLOEXEC on the first FD. ASSERT_THAT(fcntl(fd.get(), F_SETFD, FD_CLOEXEC), SyscallSucceeds()); ASSERT_THAT(fcntl(fd.get(), F_GETFD), SyscallSucceedsWithValue(FD_CLOEXEC)); // Ensure that the second FD is unaffected by the change on the first. ASSERT_THAT(fcntl(newfd.get(), F_GETFD), SyscallSucceedsWithValue(0)); } // All file description flags passed to open appear in F_GETFL. TEST(FcntlTest, GetAllFlags) { TempPath path = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); int flags = O_RDWR | O_DIRECT | O_SYNC | O_NONBLOCK | O_APPEND; FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(path.path(), flags)); // Linux forces O_LARGEFILE on all 64-bit kernels and gVisor's is 64-bit. int expected = flags | kOLargeFile; int rflags; EXPECT_THAT(rflags = fcntl(fd.get(), F_GETFL), SyscallSucceeds()); EXPECT_EQ(rflags, expected); } TEST(FcntlTest, SetFlags) { TempPath path = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(path.path(), 0)); int const flags = O_RDWR | O_DIRECT | O_SYNC | O_NONBLOCK | O_APPEND; EXPECT_THAT(fcntl(fd.get(), F_SETFL, flags), SyscallSucceeds()); // Can't set O_RDWR or O_SYNC. // Linux forces O_LARGEFILE on all 64-bit kernels and gVisor's is 64-bit. int expected = O_DIRECT | O_NONBLOCK | O_APPEND | kOLargeFile; int rflags; EXPECT_THAT(rflags = fcntl(fd.get(), F_GETFL), SyscallSucceeds()); EXPECT_EQ(rflags, expected); } TEST_F(FcntlLockTest, SetLockBadFd) { struct flock fl; fl.l_type = F_WRLCK; fl.l_whence = SEEK_SET; fl.l_start = 0; // len 0 has a special meaning: lock all bytes despite how // large the file grows. fl.l_len = 0; EXPECT_THAT(fcntl(-1, F_SETLK, &fl), SyscallFailsWithErrno(EBADF)); } TEST_F(FcntlLockTest, SetLockPipe) { int fds[2]; ASSERT_THAT(pipe(fds), SyscallSucceeds()); struct flock fl; fl.l_type = F_WRLCK; fl.l_whence = SEEK_SET; fl.l_start = 0; // Same as SetLockBadFd, but doesn't matter, we expect this to fail. fl.l_len = 0; EXPECT_THAT(fcntl(fds[0], F_SETLK, &fl), SyscallFailsWithErrno(EBADF)); EXPECT_THAT(close(fds[0]), SyscallSucceeds()); EXPECT_THAT(close(fds[1]), SyscallSucceeds()); } TEST_F(FcntlLockTest, SetLockDir) { auto dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir()); FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(dir.path(), O_RDONLY, 0666)); struct flock fl; fl.l_type = F_RDLCK; fl.l_whence = SEEK_SET; fl.l_start = 0; // Same as SetLockBadFd. fl.l_len = 0; EXPECT_THAT(fcntl(fd.get(), F_SETLK, &fl), SyscallSucceeds()); } TEST_F(FcntlLockTest, SetLockBadOpenFlagsWrite) { auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDONLY, 0666)); struct flock fl0; fl0.l_type = F_WRLCK; fl0.l_whence = SEEK_SET; fl0.l_start = 0; // Same as SetLockBadFd. fl0.l_len = 0; // Expect that setting a write lock using a read only file descriptor // won't work. EXPECT_THAT(fcntl(fd.get(), F_SETLK, &fl0), SyscallFailsWithErrno(EBADF)); } TEST_F(FcntlLockTest, SetLockBadOpenFlagsRead) { auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_WRONLY, 0666)); struct flock fl1; fl1.l_type = F_RDLCK; fl1.l_whence = SEEK_SET; fl1.l_start = 0; // Same as SetLockBadFd. fl1.l_len = 0; EXPECT_THAT(fcntl(fd.get(), F_SETLK, &fl1), SyscallFailsWithErrno(EBADF)); } TEST_F(FcntlLockTest, SetLockUnlockOnNothing) { auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR, 0666)); struct flock fl; fl.l_type = F_UNLCK; fl.l_whence = SEEK_SET; fl.l_start = 0; // Same as SetLockBadFd. fl.l_len = 0; EXPECT_THAT(fcntl(fd.get(), F_SETLK, &fl), SyscallSucceeds()); } TEST_F(FcntlLockTest, SetWriteLockSingleProc) { auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); FileDescriptor fd0 = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR, 0666)); struct flock fl; fl.l_type = F_WRLCK; fl.l_whence = SEEK_SET; fl.l_start = 0; // Same as SetLockBadFd. fl.l_len = 0; EXPECT_THAT(fcntl(fd0.get(), F_SETLK, &fl), SyscallSucceeds()); // Expect to be able to take the same lock on the same fd no problem. EXPECT_THAT(fcntl(fd0.get(), F_SETLK, &fl), SyscallSucceeds()); FileDescriptor fd1 = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR, 0666)); // Expect to be able to take the same lock from a different fd but for // the same process. EXPECT_THAT(fcntl(fd1.get(), F_SETLK, &fl), SyscallSucceeds()); } TEST_F(FcntlLockTest, SetReadLockMultiProc) { auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR, 0666)); struct flock fl; fl.l_type = F_RDLCK; fl.l_whence = SEEK_SET; fl.l_start = 0; // Same as SetLockBadFd. fl.l_len = 0; EXPECT_THAT(fcntl(fd.get(), F_SETLK, &fl), SyscallSucceeds()); // spawn a child process to take a read lock on the same file. pid_t child_pid = 0; auto cleanup = ASSERT_NO_ERRNO_AND_VALUE( SubprocessLock(file.path(), false /* write lock */, false /* nonblocking */, false /* no eintr retry */, -1 /* no socket fd */, fl.l_start, fl.l_len, &child_pid)); int status = 0; ASSERT_THAT(RetryEINTR(waitpid)(child_pid, &status, 0), SyscallSucceeds()); EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0) << "Exited with code: " << status; } TEST_F(FcntlLockTest, SetReadThenWriteLockMultiProc) { auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR, 0666)); struct flock fl; fl.l_type = F_RDLCK; fl.l_whence = SEEK_SET; fl.l_start = 0; // Same as SetLockBadFd. fl.l_len = 0; EXPECT_THAT(fcntl(fd.get(), F_SETLK, &fl), SyscallSucceeds()); // Assert that another process trying to lock on the same file will fail // with EAGAIN. It's important that we keep the fd above open so that // that the other process will contend with the lock. pid_t child_pid = 0; auto cleanup = ASSERT_NO_ERRNO_AND_VALUE( SubprocessLock(file.path(), true /* write lock */, false /* nonblocking */, false /* no eintr retry */, -1 /* no socket fd */, fl.l_start, fl.l_len, &child_pid)); int status = 0; ASSERT_THAT(RetryEINTR(waitpid)(child_pid, &status, 0), SyscallSucceeds()); EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == EAGAIN) << "Exited with code: " << status; // Close the fd: we want to test that another process can acquire the // lock after this point. fd.reset(); // Assert that another process can now acquire the lock. child_pid = 0; auto cleanup2 = ASSERT_NO_ERRNO_AND_VALUE( SubprocessLock(file.path(), true /* write lock */, false /* nonblocking */, false /* no eintr retry */, -1 /* no socket fd */, fl.l_start, fl.l_len, &child_pid)); ASSERT_THAT(RetryEINTR(waitpid)(child_pid, &status, 0), SyscallSucceeds()); EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0) << "Exited with code: " << status; } TEST_F(FcntlLockTest, SetWriteThenReadLockMultiProc) { auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR, 0666)); // Same as SetReadThenWriteLockMultiProc. struct flock fl; fl.l_type = F_WRLCK; fl.l_whence = SEEK_SET; fl.l_start = 0; // Same as SetLockBadFd. fl.l_len = 0; // Same as SetReadThenWriteLockMultiProc. EXPECT_THAT(fcntl(fd.get(), F_SETLK, &fl), SyscallSucceeds()); // Same as SetReadThenWriteLockMultiProc. pid_t child_pid = 0; auto cleanup = ASSERT_NO_ERRNO_AND_VALUE( SubprocessLock(file.path(), false /* write lock */, false /* nonblocking */, false /* no eintr retry */, -1 /* no socket fd */, fl.l_start, fl.l_len, &child_pid)); int status = 0; ASSERT_THAT(RetryEINTR(waitpid)(child_pid, &status, 0), SyscallSucceeds()); EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == EAGAIN) << "Exited with code: " << status; // Same as SetReadThenWriteLockMultiProc. fd.reset(); // Close the fd. // Same as SetReadThenWriteLockMultiProc. child_pid = 0; auto cleanup2 = ASSERT_NO_ERRNO_AND_VALUE( SubprocessLock(file.path(), false /* write lock */, false /* nonblocking */, false /* no eintr retry */, -1 /* no socket fd */, fl.l_start, fl.l_len, &child_pid)); ASSERT_THAT(RetryEINTR(waitpid)(child_pid, &status, 0), SyscallSucceeds()); EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0) << "Exited with code: " << status; } TEST_F(FcntlLockTest, SetWriteLockMultiProc) { auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR, 0666)); // Same as SetReadThenWriteLockMultiProc. struct flock fl; fl.l_type = F_WRLCK; fl.l_whence = SEEK_SET; fl.l_start = 0; // Same as SetLockBadFd. fl.l_len = 0; // Same as SetReadWriteLockMultiProc. EXPECT_THAT(fcntl(fd.get(), F_SETLK, &fl), SyscallSucceeds()); // Same as SetReadWriteLockMultiProc. pid_t child_pid = 0; auto cleanup = ASSERT_NO_ERRNO_AND_VALUE( SubprocessLock(file.path(), true /* write lock */, false /* nonblocking */, false /* no eintr retry */, -1 /* no socket fd */, fl.l_start, fl.l_len, &child_pid)); int status = 0; ASSERT_THAT(RetryEINTR(waitpid)(child_pid, &status, 0), SyscallSucceeds()); EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == EAGAIN) << "Exited with code: " << status; fd.reset(); // Close the FD. // Same as SetReadWriteLockMultiProc. child_pid = 0; auto cleanup2 = ASSERT_NO_ERRNO_AND_VALUE( SubprocessLock(file.path(), true /* write lock */, false /* nonblocking */, false /* no eintr retry */, -1 /* no socket fd */, fl.l_start, fl.l_len, &child_pid)); ASSERT_THAT(RetryEINTR(waitpid)(child_pid, &status, 0), SyscallSucceeds()); EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0) << "Exited with code: " << status; } TEST_F(FcntlLockTest, SetLockIsRegional) { auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR, 0666)); struct flock fl; fl.l_type = F_WRLCK; fl.l_whence = SEEK_SET; fl.l_start = 0; fl.l_len = 4096; // Same as SetReadWriteLockMultiProc. EXPECT_THAT(fcntl(fd.get(), F_SETLK, &fl), SyscallSucceeds()); // Same as SetReadWriteLockMultiProc. pid_t child_pid = 0; auto cleanup = ASSERT_NO_ERRNO_AND_VALUE( SubprocessLock(file.path(), true /* write lock */, false /* nonblocking */, false /* no eintr retry */, -1 /* no socket fd */, fl.l_len, 0, &child_pid)); int status = 0; ASSERT_THAT(RetryEINTR(waitpid)(child_pid, &status, 0), SyscallSucceeds()); EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0) << "Exited with code: " << status; } TEST_F(FcntlLockTest, SetLockUpgradeDowngrade) { auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR, 0666)); struct flock fl; fl.l_type = F_RDLCK; fl.l_whence = SEEK_SET; fl.l_start = 0; // Same as SetLockBadFd. fl.l_len = 0; // Same as SetReadWriteLockMultiProc. EXPECT_THAT(fcntl(fd.get(), F_SETLK, &fl), SyscallSucceeds()); // Upgrade to a write lock. This will prevent anyone else from taking // the lock. fl.l_type = F_WRLCK; EXPECT_THAT(fcntl(fd.get(), F_SETLK, &fl), SyscallSucceeds()); // Same as SetReadWriteLockMultiProc., pid_t child_pid = 0; auto cleanup = ASSERT_NO_ERRNO_AND_VALUE( SubprocessLock(file.path(), false /* write lock */, false /* nonblocking */, false /* no eintr retry */, -1 /* no socket fd */, fl.l_start, fl.l_len, &child_pid)); int status = 0; ASSERT_THAT(RetryEINTR(waitpid)(child_pid, &status, 0), SyscallSucceeds()); EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == EAGAIN) << "Exited with code: " << status; // Downgrade back to a read lock. fl.l_type = F_RDLCK; EXPECT_THAT(fcntl(fd.get(), F_SETLK, &fl), SyscallSucceeds()); // Do the same stint as before, but this time it should succeed. child_pid = 0; auto cleanup2 = ASSERT_NO_ERRNO_AND_VALUE( SubprocessLock(file.path(), false /* write lock */, false /* nonblocking */, false /* no eintr retry */, -1 /* no socket fd */, fl.l_start, fl.l_len, &child_pid)); ASSERT_THAT(RetryEINTR(waitpid)(child_pid, &status, 0), SyscallSucceeds()); EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0) << "Exited with code: " << status; } TEST_F(FcntlLockTest, SetLockDroppedOnClose) { auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR, 0666)); // While somewhat surprising, obtaining another fd to the same file and // then closing it in this process drops *all* locks. FileDescriptor other_fd = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR, 0666)); // Same as SetReadThenWriteLockMultiProc. struct flock fl; fl.l_type = F_WRLCK; fl.l_whence = SEEK_SET; fl.l_start = 0; // Same as SetLockBadFd. fl.l_len = 0; // Same as SetReadWriteLockMultiProc. EXPECT_THAT(fcntl(fd.get(), F_SETLK, &fl), SyscallSucceeds()); other_fd.reset(); // Close. // Expect to be able to get the lock, given that the close above dropped it. pid_t child_pid = 0; auto cleanup = ASSERT_NO_ERRNO_AND_VALUE( SubprocessLock(file.path(), true /* write lock */, false /* nonblocking */, false /* no eintr retry */, -1 /* no socket fd */, fl.l_start, fl.l_len, &child_pid)); int status = 0; ASSERT_THAT(RetryEINTR(waitpid)(child_pid, &status, 0), SyscallSucceeds()); EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0) << "Exited with code: " << status; } TEST_F(FcntlLockTest, SetLockUnlock) { auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR, 0666)); // Setup two regional locks with different permissions. struct flock fl0; fl0.l_type = F_WRLCK; fl0.l_whence = SEEK_SET; fl0.l_start = 0; fl0.l_len = 4096; struct flock fl1; fl1.l_type = F_RDLCK; fl1.l_whence = SEEK_SET; fl1.l_start = 4096; // Same as SetLockBadFd. fl1.l_len = 0; // Set both region locks. EXPECT_THAT(fcntl(fd.get(), F_SETLK, &fl0), SyscallSucceeds()); EXPECT_THAT(fcntl(fd.get(), F_SETLK, &fl1), SyscallSucceeds()); // Another process should fail to take a read lock on the entire file // due to the regional write lock. pid_t child_pid = 0; auto cleanup = ASSERT_NO_ERRNO_AND_VALUE(SubprocessLock( file.path(), false /* write lock */, false /* nonblocking */, false /* no eintr retry */, -1 /* no socket fd */, 0, 0, &child_pid)); int status = 0; ASSERT_THAT(RetryEINTR(waitpid)(child_pid, &status, 0), SyscallSucceeds()); EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == EAGAIN) << "Exited with code: " << status; // Then only unlock the writable one. This should ensure that other // processes can take any read lock that it wants. fl0.l_type = F_UNLCK; EXPECT_THAT(fcntl(fd.get(), F_SETLK, &fl0), SyscallSucceeds()); // Another process should now succeed to get a read lock on the entire file. child_pid = 0; auto cleanup2 = ASSERT_NO_ERRNO_AND_VALUE(SubprocessLock( file.path(), false /* write lock */, false /* nonblocking */, false /* no eintr retry */, -1 /* no socket fd */, 0, 0, &child_pid)); ASSERT_THAT(RetryEINTR(waitpid)(child_pid, &status, 0), SyscallSucceeds()); EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0) << "Exited with code: " << status; } TEST_F(FcntlLockTest, SetLockAcrossRename) { auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR, 0666)); // Setup two regional locks with different permissions. struct flock fl; fl.l_type = F_WRLCK; fl.l_whence = SEEK_SET; fl.l_start = 0; // Same as SetLockBadFd. fl.l_len = 0; // Set the region lock. EXPECT_THAT(fcntl(fd.get(), F_SETLK, &fl), SyscallSucceeds()); // Rename the file to someplace nearby. std::string const newpath = NewTempAbsPath(); EXPECT_THAT(rename(file.path().c_str(), newpath.c_str()), SyscallSucceeds()); // Another process should fail to take a read lock on the renamed file // since we still have an open handle to the inode. pid_t child_pid = 0; auto cleanup = ASSERT_NO_ERRNO_AND_VALUE( SubprocessLock(newpath, false /* write lock */, false /* nonblocking */, false /* no eintr retry */, -1 /* no socket fd */, fl.l_start, fl.l_len, &child_pid)); int status = 0; ASSERT_THAT(RetryEINTR(waitpid)(child_pid, &status, 0), SyscallSucceeds()); EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == EAGAIN) << "Exited with code: " << status; } // NOTE: The blocking tests below aren't perfect. It's hard to assert exactly // what the kernel did while handling a syscall. These tests are timing based // because there really isn't any other reasonable way to assert that correct // blocking behavior happened. // This test will verify that blocking works as expected when another process // holds a write lock when obtaining a write lock. This test will hold the lock // for some amount of time and then wait for the second process to send over the // socket_fd the amount of time it was blocked for before the lock succeeded. TEST_F(FcntlLockTest, SetWriteLockThenBlockingWriteLock) { auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR, 0666)); struct flock fl; fl.l_type = F_WRLCK; fl.l_whence = SEEK_SET; fl.l_start = 0; fl.l_len = 0; // Take the write lock. ASSERT_THAT(fcntl(fd.get(), F_SETLKW, &fl), SyscallSucceeds()); // Attempt to take the read lock in a sub process. This will immediately block // so we will release our lock after some amount of time and then assert the // amount of time the other process was blocked for. pid_t child_pid = 0; auto cleanup = ASSERT_NO_ERRNO_AND_VALUE(SubprocessLock( file.path(), true /* write lock */, true /* Blocking Lock */, true /* Retry on EINTR */, fds_[1] /* Socket fd for timing information */, fl.l_start, fl.l_len, &child_pid)); // We will wait kHoldLockForSec before we release our lock allowing the // subprocess to obtain it. constexpr absl::Duration kHoldLockFor = absl::Seconds(5); const int64_t kMinBlockTimeUsec = absl::ToInt64Microseconds(absl::Seconds(1)); absl::SleepFor(kHoldLockFor); // Unlock our write lock. fl.l_type = F_UNLCK; ASSERT_THAT(fcntl(fd.get(), F_SETLKW, &fl), SyscallSucceeds()); // Read the blocked time from the subprocess socket. int64_t subprocess_blocked_time_usec = GetSubprocessFcntlTimeInUsec(); // We must have been waiting at least kMinBlockTime. EXPECT_GT(subprocess_blocked_time_usec, kMinBlockTimeUsec); // The FCNTL write lock must always succeed as it will simply block until it // can obtain the lock. int status = 0; ASSERT_THAT(RetryEINTR(waitpid)(child_pid, &status, 0), SyscallSucceeds()); EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0) << "Exited with code: " << status; } // This test will veirfy that blocking works as expected when another process // holds a read lock when obtaining a write lock. This test will hold the lock // for some amount of time and then wait for the second process to send over the // socket_fd the amount of time it was blocked for before the lock succeeded. TEST_F(FcntlLockTest, SetReadLockThenBlockingWriteLock) { auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR, 0666)); struct flock fl; fl.l_type = F_RDLCK; fl.l_whence = SEEK_SET; fl.l_start = 0; fl.l_len = 0; // Take the write lock. ASSERT_THAT(fcntl(fd.get(), F_SETLKW, &fl), SyscallSucceeds()); // Attempt to take the read lock in a sub process. This will immediately block // so we will release our lock after some amount of time and then assert the // amount of time the other process was blocked for. pid_t child_pid = 0; auto cleanup = ASSERT_NO_ERRNO_AND_VALUE(SubprocessLock( file.path(), true /* write lock */, true /* Blocking Lock */, true /* Retry on EINTR */, fds_[1] /* Socket fd for timing information */, fl.l_start, fl.l_len, &child_pid)); // We will wait kHoldLockForSec before we release our lock allowing the // subprocess to obtain it. constexpr absl::Duration kHoldLockFor = absl::Seconds(5); const int64_t kMinBlockTimeUsec = absl::ToInt64Microseconds(absl::Seconds(1)); absl::SleepFor(kHoldLockFor); // Unlock our READ lock. fl.l_type = F_UNLCK; ASSERT_THAT(fcntl(fd.get(), F_SETLKW, &fl), SyscallSucceeds()); // Read the blocked time from the subprocess socket. int64_t subprocess_blocked_time_usec = GetSubprocessFcntlTimeInUsec(); // We must have been waiting at least kMinBlockTime. EXPECT_GT(subprocess_blocked_time_usec, kMinBlockTimeUsec); // The FCNTL write lock must always succeed as it will simply block until it // can obtain the lock. int status = 0; ASSERT_THAT(RetryEINTR(waitpid)(child_pid, &status, 0), SyscallSucceeds()); EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0) << "Exited with code: " << status; } // This test will veirfy that blocking works as expected when another process // holds a write lock when obtaining a read lock. This test will hold the lock // for some amount of time and then wait for the second process to send over the // socket_fd the amount of time it was blocked for before the lock succeeded. TEST_F(FcntlLockTest, SetWriteLockThenBlockingReadLock) { auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR, 0666)); struct flock fl; fl.l_type = F_WRLCK; fl.l_whence = SEEK_SET; fl.l_start = 0; fl.l_len = 0; // Take the write lock. ASSERT_THAT(fcntl(fd.get(), F_SETLKW, &fl), SyscallSucceeds()); // Attempt to take the read lock in a sub process. This will immediately block // so we will release our lock after some amount of time and then assert the // amount of time the other process was blocked for. pid_t child_pid = 0; auto cleanup = ASSERT_NO_ERRNO_AND_VALUE(SubprocessLock( file.path(), false /* read lock */, true /* Blocking Lock */, true /* Retry on EINTR */, fds_[1] /* Socket fd for timing information */, fl.l_start, fl.l_len, &child_pid)); // We will wait kHoldLockForSec before we release our lock allowing the // subprocess to obtain it. constexpr absl::Duration kHoldLockFor = absl::Seconds(5); const int64_t kMinBlockTimeUsec = absl::ToInt64Microseconds(absl::Seconds(1)); absl::SleepFor(kHoldLockFor); // Unlock our write lock. fl.l_type = F_UNLCK; ASSERT_THAT(fcntl(fd.get(), F_SETLKW, &fl), SyscallSucceeds()); // Read the blocked time from the subprocess socket. int64_t subprocess_blocked_time_usec = GetSubprocessFcntlTimeInUsec(); // We must have been waiting at least kMinBlockTime. EXPECT_GT(subprocess_blocked_time_usec, kMinBlockTimeUsec); // The FCNTL read lock must always succeed as it will simply block until it // can obtain the lock. int status = 0; ASSERT_THAT(RetryEINTR(waitpid)(child_pid, &status, 0), SyscallSucceeds()); EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0) << "Exited with code: " << status; } // This test will verify that when one process only holds a read lock that // another will not block while obtaining a read lock when F_SETLKW is used. TEST_F(FcntlLockTest, SetReadLockThenBlockingReadLock) { auto file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR, 0666)); struct flock fl; fl.l_type = F_RDLCK; fl.l_whence = SEEK_SET; fl.l_start = 0; fl.l_len = 0; // Take the READ lock. ASSERT_THAT(fcntl(fd.get(), F_SETLKW, &fl), SyscallSucceeds()); // Attempt to take the read lock in a sub process. Since multiple processes // can hold a read lock this should immediately return without blocking // even though we used F_SETLKW in the subprocess. pid_t child_pid = 0; auto sp = ASSERT_NO_ERRNO_AND_VALUE(SubprocessLock( file.path(), false /* read lock */, true /* Blocking Lock */, true /* Retry on EINTR */, -1 /* No fd, should not block */, fl.l_start, fl.l_len, &child_pid)); // We never release the lock and the subprocess should still obtain it without // blocking for any period of time. int status = 0; ASSERT_THAT(RetryEINTR(waitpid)(child_pid, &status, 0), SyscallSucceeds()); EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0) << "Exited with code: " << status; } TEST(FcntlTest, GetO_ASYNC) { FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); int flag_fl = -1; ASSERT_THAT(flag_fl = fcntl(s.get(), F_GETFL), SyscallSucceeds()); EXPECT_EQ(flag_fl & O_ASYNC, 0); int flag_fd = -1; ASSERT_THAT(flag_fd = fcntl(s.get(), F_GETFD), SyscallSucceeds()); EXPECT_EQ(flag_fd & O_ASYNC, 0); } TEST(FcntlTest, SetFlO_ASYNC) { FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); int before_fl = -1; ASSERT_THAT(before_fl = fcntl(s.get(), F_GETFL), SyscallSucceeds()); int before_fd = -1; ASSERT_THAT(before_fd = fcntl(s.get(), F_GETFD), SyscallSucceeds()); ASSERT_THAT(fcntl(s.get(), F_SETFL, before_fl | O_ASYNC), SyscallSucceeds()); int after_fl = -1; ASSERT_THAT(after_fl = fcntl(s.get(), F_GETFL), SyscallSucceeds()); EXPECT_EQ(after_fl, before_fl | O_ASYNC); int after_fd = -1; ASSERT_THAT(after_fd = fcntl(s.get(), F_GETFD), SyscallSucceeds()); EXPECT_EQ(after_fd, before_fd); } TEST(FcntlTest, SetFdO_ASYNC) { FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); int before_fl = -1; ASSERT_THAT(before_fl = fcntl(s.get(), F_GETFL), SyscallSucceeds()); int before_fd = -1; ASSERT_THAT(before_fd = fcntl(s.get(), F_GETFD), SyscallSucceeds()); ASSERT_THAT(fcntl(s.get(), F_SETFD, before_fd | O_ASYNC), SyscallSucceeds()); int after_fl = -1; ASSERT_THAT(after_fl = fcntl(s.get(), F_GETFL), SyscallSucceeds()); EXPECT_EQ(after_fl, before_fl); int after_fd = -1; ASSERT_THAT(after_fd = fcntl(s.get(), F_GETFD), SyscallSucceeds()); EXPECT_EQ(after_fd, before_fd); } TEST(FcntlTest, DupAfterO_ASYNC) { FileDescriptor s1 = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); int before = -1; ASSERT_THAT(before = fcntl(s1.get(), F_GETFL), SyscallSucceeds()); ASSERT_THAT(fcntl(s1.get(), F_SETFL, before | O_ASYNC), SyscallSucceeds()); FileDescriptor fd2 = ASSERT_NO_ERRNO_AND_VALUE(s1.Dup()); int after = -1; ASSERT_THAT(after = fcntl(fd2.get(), F_GETFL), SyscallSucceeds()); EXPECT_EQ(after & O_ASYNC, O_ASYNC); } TEST(FcntlTest, GetOwn) { FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); EXPECT_EQ(syscall(__NR_fcntl, s.get(), F_GETOWN), 0); MaybeSave(); } TEST(FcntlTest, GetOwnEx) { FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); f_owner_ex owner = {}; EXPECT_THAT(syscall(__NR_fcntl, s.get(), F_GETOWN_EX, &owner), SyscallSucceedsWithValue(0)); } TEST(FcntlTest, SetOwnExInvalidType) { FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); f_owner_ex owner = {}; owner.type = __pid_type(-1); EXPECT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN_EX, &owner), SyscallFailsWithErrno(EINVAL)); } TEST(FcntlTest, SetOwnExInvalidTid) { FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); f_owner_ex owner = {}; owner.type = F_OWNER_TID; owner.pid = -1; EXPECT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN_EX, &owner), SyscallFailsWithErrno(ESRCH)); } TEST(FcntlTest, SetOwnExInvalidPid) { FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); f_owner_ex owner = {}; owner.type = F_OWNER_PID; owner.pid = -1; EXPECT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN_EX, &owner), SyscallFailsWithErrno(ESRCH)); } TEST(FcntlTest, SetOwnExInvalidPgrp) { FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); f_owner_ex owner = {}; owner.type = F_OWNER_PGRP; owner.pid = -1; EXPECT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN_EX, &owner), SyscallFailsWithErrno(ESRCH)); } TEST(FcntlTest, SetOwnExTid) { FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); f_owner_ex owner = {}; owner.type = F_OWNER_TID; EXPECT_THAT(owner.pid = syscall(__NR_gettid), SyscallSucceeds()); ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN_EX, &owner), SyscallSucceeds()); EXPECT_EQ(syscall(__NR_fcntl, s.get(), F_GETOWN), owner.pid); MaybeSave(); } TEST(FcntlTest, SetOwnExPid) { FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); f_owner_ex owner = {}; owner.type = F_OWNER_PID; EXPECT_THAT(owner.pid = getpid(), SyscallSucceeds()); ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN_EX, &owner), SyscallSucceeds()); EXPECT_EQ(syscall(__NR_fcntl, s.get(), F_GETOWN), owner.pid); MaybeSave(); } TEST(FcntlTest, SetOwnExPgrp) { FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); f_owner_ex owner = {}; owner.type = F_OWNER_PGRP; EXPECT_THAT(owner.pid = getpgrp(), SyscallSucceeds()); ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN_EX, &owner), SyscallSucceeds()); // NOTE(igudger): I don't understand why, but this is flaky on Linux. // GetOwnExPgrp (below) does not have this issue. SKIP_IF(!IsRunningOnGvisor()); EXPECT_EQ(syscall(__NR_fcntl, s.get(), F_GETOWN), -owner.pid); MaybeSave(); } TEST(FcntlTest, GetOwnExTid) { FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); f_owner_ex set_owner = {}; set_owner.type = F_OWNER_TID; EXPECT_THAT(set_owner.pid = syscall(__NR_gettid), SyscallSucceeds()); ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN_EX, &set_owner), SyscallSucceeds()); f_owner_ex got_owner = {}; ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_GETOWN_EX, &got_owner), SyscallSucceedsWithValue(0)); EXPECT_EQ(got_owner.type, set_owner.type); EXPECT_EQ(got_owner.pid, set_owner.pid); } TEST(FcntlTest, GetOwnExPid) { FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); f_owner_ex set_owner = {}; set_owner.type = F_OWNER_PID; EXPECT_THAT(set_owner.pid = getpid(), SyscallSucceeds()); ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN_EX, &set_owner), SyscallSucceeds()); f_owner_ex got_owner = {}; ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_GETOWN_EX, &got_owner), SyscallSucceedsWithValue(0)); EXPECT_EQ(got_owner.type, set_owner.type); EXPECT_EQ(got_owner.pid, set_owner.pid); } TEST(FcntlTest, GetOwnExPgrp) { FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); f_owner_ex set_owner = {}; set_owner.type = F_OWNER_PGRP; EXPECT_THAT(set_owner.pid = getpgrp(), SyscallSucceeds()); ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN_EX, &set_owner), SyscallSucceeds()); f_owner_ex got_owner = {}; ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_GETOWN_EX, &got_owner), SyscallSucceedsWithValue(0)); EXPECT_EQ(got_owner.type, set_owner.type); EXPECT_EQ(got_owner.pid, set_owner.pid); } } // namespace } // namespace testing } // namespace gvisor int main(int argc, char** argv) { gvisor::testing::TestInit(&argc, &argv); const std::string setlock_on = absl::GetFlag(FLAGS_child_setlock_on); if (!setlock_on.empty()) { int socket_fd = absl::GetFlag(FLAGS_socket_fd); int fd = open(setlock_on.c_str(), O_RDWR, 0666); if (fd == -1 && errno != 0) { int err = errno; std::cerr << "CHILD open " << setlock_on << " failed " << err << std::endl; exit(err); } struct flock fl; if (absl::GetFlag(FLAGS_child_setlock_write)) { fl.l_type = F_WRLCK; } else { fl.l_type = F_RDLCK; } fl.l_whence = SEEK_SET; fl.l_start = absl::GetFlag(FLAGS_child_setlock_start); fl.l_len = absl::GetFlag(FLAGS_child_setlock_len); // Test the fcntl, no need to log, the error is unambiguously // from fcntl at this point. int err = 0; int ret = 0; gvisor::testing::MonotonicTimer timer; timer.Start(); do { ret = fcntl(fd, absl::GetFlag(FLAGS_blocking) ? F_SETLKW : F_SETLK, &fl); } while (absl::GetFlag(FLAGS_retry_eintr) && ret == -1 && errno == EINTR); auto usec = absl::ToInt64Microseconds(timer.Duration()); if (ret == -1 && errno != 0) { err = errno; } // If there is a socket fd let's send back the time in microseconds it took // to execute this syscall. if (socket_fd != -1) { gvisor::testing::WriteFd(socket_fd, reinterpret_cast<void*>(&usec), sizeof(usec)); close(socket_fd); } close(fd); exit(err); } return gvisor::testing::RunAllTests(); }