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Diffstat (limited to 'test/syscalls/linux/wait.cc')
| -rw-r--r-- | test/syscalls/linux/wait.cc | 913 |
1 files changed, 0 insertions, 913 deletions
diff --git a/test/syscalls/linux/wait.cc b/test/syscalls/linux/wait.cc deleted file mode 100644 index 944149d5e..000000000 --- a/test/syscalls/linux/wait.cc +++ /dev/null @@ -1,913 +0,0 @@ -// 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 <signal.h> -#include <sys/mman.h> -#include <sys/ptrace.h> -#include <sys/resource.h> -#include <sys/time.h> -#include <sys/types.h> -#include <sys/wait.h> -#include <unistd.h> - -#include <functional> -#include <tuple> -#include <vector> - -#include "gmock/gmock.h" -#include "gtest/gtest.h" -#include "absl/strings/str_cat.h" -#include "absl/synchronization/mutex.h" -#include "absl/time/clock.h" -#include "absl/time/time.h" -#include "test/util/cleanup.h" -#include "test/util/file_descriptor.h" -#include "test/util/logging.h" -#include "test/util/multiprocess_util.h" -#include "test/util/posix_error.h" -#include "test/util/signal_util.h" -#include "test/util/test_util.h" -#include "test/util/thread_util.h" -#include "test/util/time_util.h" - -using ::testing::UnorderedElementsAre; - -// These unit tests focus on the wait4(2) system call, but include a basic -// checks for the i386 waitpid(2) syscall, which is a subset of wait4(2). -// -// NOTE(b/22640830,b/27680907,b/29049891): Some functionality is not tested as -// it is not currently supported by gVisor: -// * Process groups. -// * Core dump status (WCOREDUMP). -// -// Tests for waiting on stopped/continued children are in sigstop.cc. - -namespace gvisor { -namespace testing { - -namespace { - -// The CloneChild function seems to need more than one page of stack space. -static const size_t kStackSize = 2 * kPageSize; - -// The child thread created in CloneAndExit runs this function. -// This child does not have the TLS setup, so it must not use glibc functions. -int CloneChild(void* priv) { - int64_t sleep = reinterpret_cast<int64_t>(priv); - SleepSafe(absl::Seconds(sleep)); - - // glibc's _exit(2) function wrapper will helpfully call exit_group(2), - // exiting the entire process. - syscall(__NR_exit, 0); - return 1; -} - -// ForkAndExit forks a child process which exits with exit_code, after -// sleeping for the specified duration (seconds). -pid_t ForkAndExit(int exit_code, int64_t sleep) { - pid_t child = fork(); - if (child == 0) { - SleepSafe(absl::Seconds(sleep)); - _exit(exit_code); - } - return child; -} - -int64_t clock_gettime_nsecs(clockid_t id) { - struct timespec ts; - TEST_PCHECK(clock_gettime(id, &ts) == 0); - return (ts.tv_sec * 1000000000 + ts.tv_nsec); -} - -void spin(int64_t sec) { - int64_t ns = sec * 1000000000; - int64_t start = clock_gettime_nsecs(CLOCK_THREAD_CPUTIME_ID); - int64_t end = start + ns; - - do { - constexpr int kLoopCount = 1000000; // large and arbitrary - // volatile to prevent the compiler from skipping this loop. - for (volatile int i = 0; i < kLoopCount; i++) { - } - } while (clock_gettime_nsecs(CLOCK_THREAD_CPUTIME_ID) < end); -} - -// ForkSpinAndExit forks a child process which exits with exit_code, after -// spinning for the specified duration (seconds). -pid_t ForkSpinAndExit(int exit_code, int64_t spintime) { - pid_t child = fork(); - if (child == 0) { - spin(spintime); - _exit(exit_code); - } - return child; -} - -absl::Duration RusageCpuTime(const struct rusage& ru) { - return absl::DurationFromTimeval(ru.ru_utime) + - absl::DurationFromTimeval(ru.ru_stime); -} - -// Returns the address of the top of the stack. -// Free with FreeStack. -uintptr_t AllocStack() { - void* addr = mmap(nullptr, kStackSize, PROT_READ | PROT_WRITE, - MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); - - if (addr == MAP_FAILED) { - return reinterpret_cast<uintptr_t>(MAP_FAILED); - } - - return reinterpret_cast<uintptr_t>(addr) + kStackSize; -} - -// Frees a stack page allocated with AllocStack. -int FreeStack(uintptr_t addr) { - addr -= kStackSize; - return munmap(reinterpret_cast<void*>(addr), kPageSize); -} - -// CloneAndExit clones a child thread, which exits with 0 after sleeping for -// the specified duration (must be in seconds). extra_flags are ORed against -// the standard clone(2) flags. -int CloneAndExit(int64_t sleep, uintptr_t stack, int extra_flags) { - return clone(CloneChild, reinterpret_cast<void*>(stack), - CLONE_FILES | CLONE_FS | CLONE_SIGHAND | CLONE_VM | extra_flags, - reinterpret_cast<void*>(sleep)); -} - -// Simple wrappers around wait4(2) and waitid(2) that ignore interrupts. -constexpr auto Wait4 = RetryEINTR(wait4); -constexpr auto Waitid = RetryEINTR(waitid); - -// Fixture for tests parameterized by a function that waits for any child to -// exit with the given options, checks that it exited with the given code, and -// then returns its PID. -// -// N.B. These tests run in a multi-threaded environment. We assume that -// background threads do not create child processes and are not themselves -// created with clone(... | SIGCHLD). Either may cause these tests to -// erroneously wait on child processes/threads. -class WaitAnyChildTest : public ::testing::TestWithParam< - std::function<PosixErrorOr<pid_t>(int, int)>> { - protected: - PosixErrorOr<pid_t> WaitAny(int code) { return WaitAnyWithOptions(code, 0); } - - PosixErrorOr<pid_t> WaitAnyWithOptions(int code, int options) { - return GetParam()(code, options); - } -}; - -// Wait for any child to exit. -TEST_P(WaitAnyChildTest, Fork) { - pid_t child; - ASSERT_THAT(child = ForkAndExit(0, 0), SyscallSucceeds()); - - EXPECT_THAT(WaitAny(0), IsPosixErrorOkAndHolds(child)); -} - -// Call wait4 for any process after the child has already exited. -TEST_P(WaitAnyChildTest, AfterExit) { - pid_t child; - ASSERT_THAT(child = ForkAndExit(0, 0), SyscallSucceeds()); - - absl::SleepFor(absl::Seconds(5)); - - EXPECT_THAT(WaitAny(0), IsPosixErrorOkAndHolds(child)); -} - -// Wait for multiple children to exit, waiting for either at a time. -TEST_P(WaitAnyChildTest, MultipleFork) { - pid_t child1, child2; - ASSERT_THAT(child1 = ForkAndExit(0, 0), SyscallSucceeds()); - ASSERT_THAT(child2 = ForkAndExit(0, 0), SyscallSucceeds()); - - std::vector<pid_t> pids; - pids.push_back(ASSERT_NO_ERRNO_AND_VALUE(WaitAny(0))); - pids.push_back(ASSERT_NO_ERRNO_AND_VALUE(WaitAny(0))); - EXPECT_THAT(pids, UnorderedElementsAre(child1, child2)); -} - -// Wait for any child to exit. -// A non-CLONE_THREAD child which sends SIGCHLD upon exit behaves much like -// a forked process. -TEST_P(WaitAnyChildTest, CloneSIGCHLD) { - uintptr_t stack; - ASSERT_THAT(stack = AllocStack(), SyscallSucceeds()); - auto free = - Cleanup([stack] { ASSERT_THAT(FreeStack(stack), SyscallSucceeds()); }); - - int child; - ASSERT_THAT(child = CloneAndExit(0, stack, SIGCHLD), SyscallSucceeds()); - - EXPECT_THAT(WaitAny(0), IsPosixErrorOkAndHolds(child)); -} - -// Wait for a child thread and process. -TEST_P(WaitAnyChildTest, ForkAndClone) { - pid_t process; - ASSERT_THAT(process = ForkAndExit(0, 0), SyscallSucceeds()); - - uintptr_t stack; - ASSERT_THAT(stack = AllocStack(), SyscallSucceeds()); - auto free = - Cleanup([stack] { ASSERT_THAT(FreeStack(stack), SyscallSucceeds()); }); - - int thread; - // Send SIGCHLD for normal wait semantics. - ASSERT_THAT(thread = CloneAndExit(0, stack, SIGCHLD), SyscallSucceeds()); - - std::vector<pid_t> pids; - pids.push_back(ASSERT_NO_ERRNO_AND_VALUE(WaitAny(0))); - pids.push_back(ASSERT_NO_ERRNO_AND_VALUE(WaitAny(0))); - EXPECT_THAT(pids, UnorderedElementsAre(process, thread)); -} - -// Return immediately if no child has exited. -TEST_P(WaitAnyChildTest, WaitWNOHANG) { - EXPECT_THAT(WaitAnyWithOptions(0, WNOHANG), - PosixErrorIs(ECHILD, ::testing::_)); -} - -// Bad options passed -TEST_P(WaitAnyChildTest, BadOption) { - EXPECT_THAT(WaitAnyWithOptions(0, 123456), - PosixErrorIs(EINVAL, ::testing::_)); -} - -TEST_P(WaitAnyChildTest, WaitedChildRusage) { - struct rusage before; - ASSERT_THAT(getrusage(RUSAGE_CHILDREN, &before), SyscallSucceeds()); - - pid_t child; - constexpr absl::Duration kSpin = absl::Seconds(3); - ASSERT_THAT(child = ForkSpinAndExit(0, absl::ToInt64Seconds(kSpin)), - SyscallSucceeds()); - ASSERT_THAT(WaitAny(0), IsPosixErrorOkAndHolds(child)); - - struct rusage after; - ASSERT_THAT(getrusage(RUSAGE_CHILDREN, &after), SyscallSucceeds()); - - EXPECT_GE(RusageCpuTime(after) - RusageCpuTime(before), kSpin); -} - -TEST_P(WaitAnyChildTest, IgnoredChildRusage) { - // "POSIX.1-2001 specifies that if the disposition of SIGCHLD is - // set to SIG_IGN or the SA_NOCLDWAIT flag is set for SIGCHLD (see - // sigaction(2)), then children that terminate do not become zombies and a - // call to wait() or waitpid() will block until all children have terminated, - // and then fail with errno set to ECHILD." - waitpid(2) - // - // "RUSAGE_CHILDREN: Return resource usage statistics for all children of the - // calling process that have terminated *and been waited for*." - - // getrusage(2), emphasis added - - struct sigaction sa; - sa.sa_handler = SIG_IGN; - const auto cleanup_sigact = - ASSERT_NO_ERRNO_AND_VALUE(ScopedSigaction(SIGCHLD, sa)); - - struct rusage before; - ASSERT_THAT(getrusage(RUSAGE_CHILDREN, &before), SyscallSucceeds()); - - const absl::Duration start = - absl::Nanoseconds(clock_gettime_nsecs(CLOCK_MONOTONIC)); - - constexpr absl::Duration kSpin = absl::Seconds(3); - - // ForkAndSpin uses CLOCK_THREAD_CPUTIME_ID, which is lower resolution than, - // and may diverge from, CLOCK_MONOTONIC, so we allow a small grace period but - // still check that we blocked for a while. - constexpr absl::Duration kSpinGrace = absl::Milliseconds(100); - - pid_t child; - ASSERT_THAT(child = ForkSpinAndExit(0, absl::ToInt64Seconds(kSpin)), - SyscallSucceeds()); - ASSERT_THAT(WaitAny(0), PosixErrorIs(ECHILD, ::testing::_)); - const absl::Duration end = - absl::Nanoseconds(clock_gettime_nsecs(CLOCK_MONOTONIC)); - EXPECT_GE(end - start, kSpin - kSpinGrace); - - struct rusage after; - ASSERT_THAT(getrusage(RUSAGE_CHILDREN, &after), SyscallSucceeds()); - EXPECT_EQ(before.ru_utime.tv_sec, after.ru_utime.tv_sec); - EXPECT_EQ(before.ru_utime.tv_usec, after.ru_utime.tv_usec); - EXPECT_EQ(before.ru_stime.tv_sec, after.ru_stime.tv_sec); - EXPECT_EQ(before.ru_stime.tv_usec, after.ru_stime.tv_usec); -} - -INSTANTIATE_TEST_SUITE_P( - Waiters, WaitAnyChildTest, - ::testing::Values( - [](int code, int options) -> PosixErrorOr<pid_t> { - int status; - auto const pid = Wait4(-1, &status, options, nullptr); - MaybeSave(); - if (pid < 0) { - return PosixError(errno, "wait4"); - } - if (!WIFEXITED(status) || WEXITSTATUS(status) != code) { - return PosixError( - EINVAL, absl::StrCat("unexpected wait status: got ", status, - ", wanted ", code)); - } - return static_cast<pid_t>(pid); - }, - [](int code, int options) -> PosixErrorOr<pid_t> { - siginfo_t si; - auto const rv = Waitid(P_ALL, 0, &si, WEXITED | options); - MaybeSave(); - if (rv < 0) { - return PosixError(errno, "waitid"); - } - if (si.si_signo != SIGCHLD) { - return PosixError( - EINVAL, absl::StrCat("unexpected signo: got ", si.si_signo, - ", wanted ", SIGCHLD)); - } - if (si.si_status != code) { - return PosixError( - EINVAL, absl::StrCat("unexpected status: got ", si.si_status, - ", wanted ", code)); - } - if (si.si_code != CLD_EXITED) { - return PosixError(EINVAL, - absl::StrCat("unexpected code: got ", si.si_code, - ", wanted ", CLD_EXITED)); - } - auto const uid = getuid(); - if (si.si_uid != uid) { - return PosixError(EINVAL, - absl::StrCat("unexpected uid: got ", si.si_uid, - ", wanted ", uid)); - } - return static_cast<pid_t>(si.si_pid); - })); - -// Fixture for tests parameterized by a (sysno, function) tuple. The function -// takes the PID of a specific child to wait for, waits for it to exit, and -// checks that it exits with the given code. -class WaitSpecificChildTest - : public ::testing::TestWithParam< - std::tuple<int, std::function<PosixError(pid_t, int, int)>>> { - protected: - int Sysno() { return std::get<0>(GetParam()); } - - PosixError WaitForWithOptions(pid_t pid, int options, int code) { - return std::get<1>(GetParam())(pid, options, code); - } - - PosixError WaitFor(pid_t pid, int code) { - return std::get<1>(GetParam())(pid, 0, code); - } -}; - -// Wait for specific child to exit. -TEST_P(WaitSpecificChildTest, Fork) { - pid_t child; - ASSERT_THAT(child = ForkAndExit(0, 0), SyscallSucceeds()); - - EXPECT_NO_ERRNO(WaitFor(child, 0)); -} - -// Non-zero exit codes are correctly propagated. -TEST_P(WaitSpecificChildTest, NormalExit) { - pid_t child; - ASSERT_THAT(child = ForkAndExit(42, 0), SyscallSucceeds()); - - EXPECT_NO_ERRNO(WaitFor(child, 42)); -} - -// Wait for multiple children to exit. -TEST_P(WaitSpecificChildTest, MultipleFork) { - pid_t child1, child2; - ASSERT_THAT(child1 = ForkAndExit(0, 0), SyscallSucceeds()); - ASSERT_THAT(child2 = ForkAndExit(0, 0), SyscallSucceeds()); - - EXPECT_NO_ERRNO(WaitFor(child1, 0)); - EXPECT_NO_ERRNO(WaitFor(child2, 0)); -} - -// Wait for multiple children to exit, out of the order they were created. -TEST_P(WaitSpecificChildTest, MultipleForkOutOfOrder) { - pid_t child1, child2; - ASSERT_THAT(child1 = ForkAndExit(0, 0), SyscallSucceeds()); - ASSERT_THAT(child2 = ForkAndExit(0, 0), SyscallSucceeds()); - - EXPECT_NO_ERRNO(WaitFor(child2, 0)); - EXPECT_NO_ERRNO(WaitFor(child1, 0)); -} - -// Wait for specific child to exit, entering wait4 before the exit occurs. -TEST_P(WaitSpecificChildTest, ForkSleep) { - pid_t child; - ASSERT_THAT(child = ForkAndExit(0, 5), SyscallSucceeds()); - - EXPECT_NO_ERRNO(WaitFor(child, 0)); -} - -// Wait should block until the child exits. -TEST_P(WaitSpecificChildTest, ForkBlock) { - pid_t child; - - auto start = absl::Now(); - ASSERT_THAT(child = ForkAndExit(0, 5), SyscallSucceeds()); - - EXPECT_NO_ERRNO(WaitFor(child, 0)); - - EXPECT_GE(absl::Now() - start, absl::Seconds(5)); -} - -// Waiting after the child has already exited returns immediately. -TEST_P(WaitSpecificChildTest, AfterExit) { - pid_t child; - ASSERT_THAT(child = ForkAndExit(0, 0), SyscallSucceeds()); - - absl::SleepFor(absl::Seconds(5)); - - EXPECT_NO_ERRNO(WaitFor(child, 0)); -} - -// Wait for child of sibling thread. -TEST_P(WaitSpecificChildTest, SiblingChildren) { - absl::Mutex mu; - pid_t child; - bool ready = false; - bool stop = false; - - ScopedThread t([&] { - absl::MutexLock ml(&mu); - EXPECT_THAT(child = ForkAndExit(0, 0), SyscallSucceeds()); - ready = true; - mu.Await(absl::Condition(&stop)); - }); - - // N.B. This must be declared after ScopedThread, so it is destructed first, - // thus waking the thread. - absl::MutexLock ml(&mu); - mu.Await(absl::Condition(&ready)); - - EXPECT_NO_ERRNO(WaitFor(child, 0)); - - // Keep the sibling alive until after we've waited so the child isn't - // reparented. - stop = true; -} - -// Waiting for child of sibling thread not allowed with WNOTHREAD. -TEST_P(WaitSpecificChildTest, SiblingChildrenWNOTHREAD) { - // Linux added WNOTHREAD support to waitid(2) in - // 91c4e8ea8f05916df0c8a6f383508ac7c9e10dba ("wait: allow sys_waitid() to - // accept __WNOTHREAD/__WCLONE/__WALL"). i.e., Linux 4.7. - // - // Skip the test if it isn't supported yet. - if (Sysno() == SYS_waitid) { - int ret = waitid(P_ALL, 0, nullptr, WEXITED | WNOHANG | __WNOTHREAD); - SKIP_IF(ret < 0 && errno == EINVAL); - } - - absl::Mutex mu; - pid_t child; - bool ready = false; - bool stop = false; - - ScopedThread t([&] { - absl::MutexLock ml(&mu); - EXPECT_THAT(child = ForkAndExit(0, 0), SyscallSucceeds()); - ready = true; - mu.Await(absl::Condition(&stop)); - - // This thread can wait on child. - EXPECT_NO_ERRNO(WaitForWithOptions(child, __WNOTHREAD, 0)); - }); - - // N.B. This must be declared after ScopedThread, so it is destructed first, - // thus waking the thread. - absl::MutexLock ml(&mu); - mu.Await(absl::Condition(&ready)); - - // This thread can't wait on child. - EXPECT_THAT(WaitForWithOptions(child, __WNOTHREAD, 0), - PosixErrorIs(ECHILD, ::testing::_)); - - // Keep the sibling alive until after we've waited so the child isn't - // reparented. - stop = true; -} - -// Wait for specific child to exit. -// A non-CLONE_THREAD child which sends SIGCHLD upon exit behaves much like -// a forked process. -TEST_P(WaitSpecificChildTest, CloneSIGCHLD) { - uintptr_t stack; - ASSERT_THAT(stack = AllocStack(), SyscallSucceeds()); - auto free = - Cleanup([stack] { ASSERT_THAT(FreeStack(stack), SyscallSucceeds()); }); - - int child; - ASSERT_THAT(child = CloneAndExit(0, stack, SIGCHLD), SyscallSucceeds()); - - EXPECT_NO_ERRNO(WaitFor(child, 0)); -} - -// Wait for specific child to exit. -// A non-CLONE_THREAD child which does not send SIGCHLD upon exit can be waited -// on, but returns ECHILD. -TEST_P(WaitSpecificChildTest, CloneNoSIGCHLD) { - uintptr_t stack; - ASSERT_THAT(stack = AllocStack(), SyscallSucceeds()); - auto free = - Cleanup([stack] { ASSERT_THAT(FreeStack(stack), SyscallSucceeds()); }); - - int child; - ASSERT_THAT(child = CloneAndExit(0, stack, 0), SyscallSucceeds()); - - EXPECT_THAT(WaitFor(child, 0), PosixErrorIs(ECHILD, ::testing::_)); -} - -// Waiting after the child has already exited returns immediately. -TEST_P(WaitSpecificChildTest, CloneAfterExit) { - uintptr_t stack; - ASSERT_THAT(stack = AllocStack(), SyscallSucceeds()); - auto free = - Cleanup([stack] { ASSERT_THAT(FreeStack(stack), SyscallSucceeds()); }); - - int child; - // Send SIGCHLD for normal wait semantics. - ASSERT_THAT(child = CloneAndExit(0, stack, SIGCHLD), SyscallSucceeds()); - - absl::SleepFor(absl::Seconds(5)); - - EXPECT_NO_ERRNO(WaitFor(child, 0)); -} - -// A CLONE_THREAD child cannot be waited on. -TEST_P(WaitSpecificChildTest, CloneThread) { - uintptr_t stack; - ASSERT_THAT(stack = AllocStack(), SyscallSucceeds()); - auto free = - Cleanup([stack] { ASSERT_THAT(FreeStack(stack), SyscallSucceeds()); }); - - int child; - ASSERT_THAT(child = CloneAndExit(15, stack, CLONE_THREAD), SyscallSucceeds()); - auto start = absl::Now(); - - EXPECT_THAT(WaitFor(child, 0), PosixErrorIs(ECHILD, ::testing::_)); - - // Ensure wait4 didn't block. - EXPECT_LE(absl::Now() - start, absl::Seconds(10)); - - // Since we can't wait on the child, we sleep to try to avoid freeing its - // stack before it exits. - absl::SleepFor(absl::Seconds(5)); -} - -// A child that does not send a SIGCHLD on exit may be waited on with -// the __WCLONE flag. -TEST_P(WaitSpecificChildTest, CloneWCLONE) { - // Linux added WCLONE support to waitid(2) in - // 91c4e8ea8f05916df0c8a6f383508ac7c9e10dba ("wait: allow sys_waitid() to - // accept __WNOTHREAD/__WCLONE/__WALL"). i.e., Linux 4.7. - // - // Skip the test if it isn't supported yet. - if (Sysno() == SYS_waitid) { - int ret = waitid(P_ALL, 0, nullptr, WEXITED | WNOHANG | __WCLONE); - SKIP_IF(ret < 0 && errno == EINVAL); - } - - uintptr_t stack; - ASSERT_THAT(stack = AllocStack(), SyscallSucceeds()); - auto free = - Cleanup([stack] { ASSERT_THAT(FreeStack(stack), SyscallSucceeds()); }); - - int child; - ASSERT_THAT(child = CloneAndExit(0, stack, 0), SyscallSucceeds()); - - EXPECT_NO_ERRNO(WaitForWithOptions(child, __WCLONE, 0)); -} - -// A forked child cannot be waited on with WCLONE. -TEST_P(WaitSpecificChildTest, ForkWCLONE) { - // Linux added WCLONE support to waitid(2) in - // 91c4e8ea8f05916df0c8a6f383508ac7c9e10dba ("wait: allow sys_waitid() to - // accept __WNOTHREAD/__WCLONE/__WALL"). i.e., Linux 4.7. - // - // Skip the test if it isn't supported yet. - if (Sysno() == SYS_waitid) { - int ret = waitid(P_ALL, 0, nullptr, WEXITED | WNOHANG | __WCLONE); - SKIP_IF(ret < 0 && errno == EINVAL); - } - - pid_t child; - ASSERT_THAT(child = ForkAndExit(0, 0), SyscallSucceeds()); - - EXPECT_THAT(WaitForWithOptions(child, WNOHANG | __WCLONE, 0), - PosixErrorIs(ECHILD, ::testing::_)); - - EXPECT_NO_ERRNO(WaitFor(child, 0)); -} - -// Any type of child can be waited on with WALL. -TEST_P(WaitSpecificChildTest, WALL) { - // Linux added WALL support to waitid(2) in - // 91c4e8ea8f05916df0c8a6f383508ac7c9e10dba ("wait: allow sys_waitid() to - // accept __WNOTHREAD/__WCLONE/__WALL"). i.e., Linux 4.7. - // - // Skip the test if it isn't supported yet. - if (Sysno() == SYS_waitid) { - int ret = waitid(P_ALL, 0, nullptr, WEXITED | WNOHANG | __WALL); - SKIP_IF(ret < 0 && errno == EINVAL); - } - - pid_t child; - ASSERT_THAT(child = ForkAndExit(0, 0), SyscallSucceeds()); - - EXPECT_NO_ERRNO(WaitForWithOptions(child, __WALL, 0)); - - uintptr_t stack; - ASSERT_THAT(stack = AllocStack(), SyscallSucceeds()); - auto free = - Cleanup([stack] { ASSERT_THAT(FreeStack(stack), SyscallSucceeds()); }); - - ASSERT_THAT(child = CloneAndExit(0, stack, 0), SyscallSucceeds()); - - EXPECT_NO_ERRNO(WaitForWithOptions(child, __WALL, 0)); -} - -// Return ECHILD for bad child. -TEST_P(WaitSpecificChildTest, BadChild) { - EXPECT_THAT(WaitFor(42, 0), PosixErrorIs(ECHILD, ::testing::_)); -} - -// Wait for a child process that only exits after calling execve(2) from a -// non-leader thread. -TEST_P(WaitSpecificChildTest, AfterChildExecve) { - ExecveArray const owned_child_argv = {"/bin/true"}; - char* const* const child_argv = owned_child_argv.get(); - - uintptr_t stack; - ASSERT_THAT(stack = AllocStack(), SyscallSucceeds()); - auto free = - Cleanup([stack] { ASSERT_THAT(FreeStack(stack), SyscallSucceeds()); }); - - pid_t const child = fork(); - if (child == 0) { - // Give the parent some time to start waiting. - SleepSafe(absl::Seconds(5)); - // Pass CLONE_VFORK to block the original thread in the child process until - // the clone thread calls execve, annihilating them both. (This means that - // if clone returns at all, something went wrong.) - // - // N.B. clone(2) is not officially async-signal-safe, but at minimum glibc's - // x86_64 implementation is safe. See glibc - // sysdeps/unix/sysv/linux/x86_64/clone.S. - clone( - +[](void* arg) { - auto child_argv = static_cast<char* const*>(arg); - execve(child_argv[0], child_argv, /* envp = */ nullptr); - return errno; - }, - reinterpret_cast<void*>(stack), - CLONE_FILES | CLONE_FS | CLONE_SIGHAND | CLONE_THREAD | CLONE_VM | - CLONE_VFORK, - const_cast<char**>(child_argv)); - _exit(errno); - } - ASSERT_THAT(child, SyscallSucceeds()); - EXPECT_NO_ERRNO(WaitFor(child, 0)); -} - -PosixError CheckWait4(pid_t pid, int options, int code) { - int status; - auto const rv = Wait4(pid, &status, options, nullptr); - MaybeSave(); - if (rv < 0) { - return PosixError(errno, "wait4"); - } else if (rv != pid) { - return PosixError( - EINVAL, absl::StrCat("unexpected pid: got ", rv, ", wanted ", pid)); - } - if (!WIFEXITED(status) || WEXITSTATUS(status) != code) { - return PosixError(EINVAL, absl::StrCat("unexpected wait status: got ", - status, ", wanted ", code)); - } - return NoError(); -}; - -PosixError CheckWaitid(pid_t pid, int options, int code) { - siginfo_t si; - auto const rv = Waitid(P_PID, pid, &si, options | WEXITED); - MaybeSave(); - if (rv < 0) { - return PosixError(errno, "waitid"); - } - if (si.si_pid != pid) { - return PosixError(EINVAL, absl::StrCat("unexpected pid: got ", si.si_pid, - ", wanted ", pid)); - } - if (si.si_signo != SIGCHLD) { - return PosixError(EINVAL, absl::StrCat("unexpected signo: got ", - si.si_signo, ", wanted ", SIGCHLD)); - } - if (si.si_status != code) { - return PosixError(EINVAL, absl::StrCat("unexpected status: got ", - si.si_status, ", wanted ", code)); - } - if (si.si_code != CLD_EXITED) { - return PosixError(EINVAL, absl::StrCat("unexpected code: got ", si.si_code, - ", wanted ", CLD_EXITED)); - } - return NoError(); -} - -INSTANTIATE_TEST_SUITE_P( - Waiters, WaitSpecificChildTest, - ::testing::Values(std::make_tuple(SYS_wait4, CheckWait4), - std::make_tuple(SYS_waitid, CheckWaitid))); - -// WIFEXITED, WIFSIGNALED, WTERMSIG indicate signal exit. -TEST(WaitTest, SignalExit) { - pid_t child; - ASSERT_THAT(child = ForkAndExit(0, 10), SyscallSucceeds()); - - EXPECT_THAT(kill(child, SIGKILL), SyscallSucceeds()); - - int status; - EXPECT_THAT(Wait4(child, &status, 0, nullptr), - SyscallSucceedsWithValue(child)); - - EXPECT_FALSE(WIFEXITED(status)); - EXPECT_TRUE(WIFSIGNALED(status)); - EXPECT_EQ(SIGKILL, WTERMSIG(status)); -} - -// waitid requires at least one option. -TEST(WaitTest, WaitidOptions) { - EXPECT_THAT(Waitid(P_ALL, 0, nullptr, 0), SyscallFailsWithErrno(EINVAL)); -} - -// waitid does not wait for a child to exit if not passed WEXITED. -TEST(WaitTest, WaitidNoWEXITED) { - pid_t child; - ASSERT_THAT(child = ForkAndExit(0, 0), SyscallSucceeds()); - EXPECT_THAT(Waitid(P_ALL, 0, nullptr, WSTOPPED), - SyscallFailsWithErrno(ECHILD)); - EXPECT_THAT(Waitid(P_ALL, 0, nullptr, WEXITED), SyscallSucceeds()); -} - -// WNOWAIT allows the same wait result to be returned again. -TEST(WaitTest, WaitidWNOWAIT) { - pid_t child; - ASSERT_THAT(child = ForkAndExit(42, 0), SyscallSucceeds()); - - siginfo_t info; - ASSERT_THAT(Waitid(P_PID, child, &info, WEXITED | WNOWAIT), - SyscallSucceeds()); - EXPECT_EQ(child, info.si_pid); - EXPECT_EQ(SIGCHLD, info.si_signo); - EXPECT_EQ(CLD_EXITED, info.si_code); - EXPECT_EQ(42, info.si_status); - - ASSERT_THAT(Waitid(P_PID, child, &info, WEXITED), SyscallSucceeds()); - EXPECT_EQ(child, info.si_pid); - EXPECT_EQ(SIGCHLD, info.si_signo); - EXPECT_EQ(CLD_EXITED, info.si_code); - EXPECT_EQ(42, info.si_status); - - EXPECT_THAT(Waitid(P_PID, child, &info, WEXITED), - SyscallFailsWithErrno(ECHILD)); -} - -// waitpid(pid, status, options) is equivalent to -// wait4(pid, status, options, nullptr). -// This is a dedicated syscall on i386, glibc maps it to wait4 on amd64. -TEST(WaitTest, WaitPid) { - pid_t child; - ASSERT_THAT(child = ForkAndExit(42, 0), SyscallSucceeds()); - - int status; - EXPECT_THAT(RetryEINTR(waitpid)(child, &status, 0), - SyscallSucceedsWithValue(child)); - - EXPECT_TRUE(WIFEXITED(status)); - EXPECT_EQ(42, WEXITSTATUS(status)); -} - -// Test that signaling a zombie succeeds. This is a signals test that is in this -// file for some reason. -TEST(WaitTest, KillZombie) { - pid_t child; - ASSERT_THAT(child = ForkAndExit(42, 0), SyscallSucceeds()); - - // Sleep for three seconds to ensure the child has exited. - absl::SleepFor(absl::Seconds(3)); - - // The child is now a zombie. Check that killing it returns 0. - EXPECT_THAT(kill(child, SIGTERM), SyscallSucceeds()); - EXPECT_THAT(kill(child, 0), SyscallSucceeds()); - - EXPECT_THAT(Wait4(child, nullptr, 0, nullptr), - SyscallSucceedsWithValue(child)); -} - -TEST(WaitTest, Wait4Rusage) { - pid_t child; - constexpr absl::Duration kSpin = absl::Seconds(3); - ASSERT_THAT(child = ForkSpinAndExit(21, absl::ToInt64Seconds(kSpin)), - SyscallSucceeds()); - - int status; - struct rusage rusage = {}; - ASSERT_THAT(Wait4(child, &status, 0, &rusage), - SyscallSucceedsWithValue(child)); - - EXPECT_TRUE(WIFEXITED(status)); - EXPECT_EQ(21, WEXITSTATUS(status)); - - EXPECT_GE(RusageCpuTime(rusage), kSpin); -} - -TEST(WaitTest, WaitidRusage) { - pid_t child; - constexpr absl::Duration kSpin = absl::Seconds(3); - ASSERT_THAT(child = ForkSpinAndExit(27, absl::ToInt64Seconds(kSpin)), - SyscallSucceeds()); - - siginfo_t si = {}; - struct rusage rusage = {}; - - // From waitid(2): - // The raw waitid() system call takes a fifth argument, of type - // struct rusage *. If this argument is non-NULL, then it is used - // to return resource usage information about the child, in the - // same manner as wait4(2). - EXPECT_THAT( - RetryEINTR(syscall)(SYS_waitid, P_PID, child, &si, WEXITED, &rusage), - SyscallSucceeds()); - EXPECT_EQ(si.si_signo, SIGCHLD); - EXPECT_EQ(si.si_code, CLD_EXITED); - EXPECT_EQ(si.si_status, 27); - EXPECT_EQ(si.si_pid, child); - - EXPECT_GE(RusageCpuTime(rusage), kSpin); -} - -// After bf959931ddb88c4e4366e96dd22e68fa0db9527c ("wait/ptrace: assume __WALL -// if the child is traced") (Linux 4.7), tracees are always eligible for -// waiting, regardless of type. -TEST(WaitTest, TraceeWALL) { - int fds[2]; - ASSERT_THAT(pipe(fds), SyscallSucceeds()); - FileDescriptor rfd(fds[0]); - FileDescriptor wfd(fds[1]); - - pid_t child = fork(); - if (child == 0) { - // Child. - rfd.reset(); - - TEST_PCHECK(ptrace(PTRACE_TRACEME, 0, nullptr, nullptr) == 0); - - // Notify parent that we're now a tracee. - wfd.reset(); - - _exit(0); - } - ASSERT_THAT(child, SyscallSucceeds()); - - wfd.reset(); - - // Wait for child to become tracee. - char c; - EXPECT_THAT(ReadFd(rfd.get(), &c, sizeof(c)), SyscallSucceedsWithValue(0)); - - // We can wait on the fork child with WCLONE, as it is a tracee. - int status; - if (IsRunningOnGvisor()) { - ASSERT_THAT(Wait4(child, &status, __WCLONE, nullptr), - SyscallSucceedsWithValue(child)); - - EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0) << status; - } else { - // On older versions of Linux, we may get ECHILD. - ASSERT_THAT(Wait4(child, &status, __WCLONE, nullptr), - ::testing::AnyOf(SyscallSucceedsWithValue(child), - SyscallFailsWithErrno(ECHILD))); - } -} - -} // namespace - -} // namespace testing -} // namespace gvisor |