Open source system call tests.

PiperOrigin-RevId: 224886231
Change-Id: I0fccb4d994601739d8b16b1d4e6b31f40297fb22

1 files changed, 468 insertions, 0 deletions

diff --git a/test/syscalls/linux/epoll.cc b/test/syscalls/linux/epoll.cc
new file mode 100644
index 000000000..9ae87c00b
--- /dev/null
+++ b/test/syscalls/linux/epoll.cc
@@ -0,0 +1,468 @@
+// Copyright 2018 Google LLC
+//
+// 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 <errno.h>
+#include <limits.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/epoll.h>
+#include <sys/eventfd.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "gtest/gtest.h"
+#include "test/util/file_descriptor.h"
+#include "test/util/posix_error.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+constexpr int kFDsPerEpoll = 3;
+constexpr uint64_t kMagicConstant = 0x0102030405060708;
+
+// Returns a new epoll file descriptor.
+PosixErrorOr<FileDescriptor> NewEpollFD() {
+  // "Since Linux 2.6.8, the size argument is ignored, but must be greater than
+  // zero." - epoll_create(2)
+  int fd = epoll_create(/* size = */ 1);
+  MaybeSave();
+  if (fd < 0) {
+    return PosixError(errno, "epoll_create");
+  }
+  return FileDescriptor(fd);
+}
+
+// Returns a new eventfd.
+PosixErrorOr<FileDescriptor> NewEventFD() {
+  int fd = eventfd(/* initval = */ 0, /* flags = */ 0);
+  MaybeSave();
+  if (fd < 0) {
+    return PosixError(errno, "eventfd");
+  }
+  return FileDescriptor(fd);
+}
+
+// Registers `target_fd` with the epoll instance represented by `epoll_fd` for
+// the epoll events `events`. Events on `target_fd` will be indicated by setting
+// data.u64 to `data` in the returned epoll_event.
+PosixError RegisterEpollFD(int epoll_fd, int target_fd, int events,
+                           uint64_t data) {
+  struct epoll_event event;
+  event.events = events;
+  event.data.u64 = data;
+  int rc = epoll_ctl(epoll_fd, EPOLL_CTL_ADD, target_fd, &event);
+  MaybeSave();
+  if (rc < 0) {
+    return PosixError(errno, "epoll_ctl");
+  }
+  return NoError();
+}
+
+uint64_t ms_elapsed(const struct timespec* begin, const struct timespec* end) {
+  return (end->tv_sec - begin->tv_sec) * 1000 +
+         (end->tv_nsec - begin->tv_nsec) / 1000000;
+}
+
+TEST(EpollTest, AllWritable) {
+  auto epollfd = ASSERT_NO_ERRNO_AND_VALUE(NewEpollFD());
+  std::vector<FileDescriptor> eventfds;
+  for (int i = 0; i < kFDsPerEpoll; i++) {
+    eventfds.push_back(ASSERT_NO_ERRNO_AND_VALUE(NewEventFD()));
+    ASSERT_NO_ERRNO(RegisterEpollFD(epollfd.get(), eventfds[i].get(),
+                                    EPOLLIN | EPOLLOUT, kMagicConstant + i));
+  }
+
+  struct epoll_event result[kFDsPerEpoll];
+  ASSERT_THAT(RetryEINTR(epoll_wait)(epollfd.get(), result, kFDsPerEpoll, -1),
+              SyscallSucceedsWithValue(kFDsPerEpoll));
+  // TODO: Why do some tests check epoll_event::data, and others
+  // don't? Does Linux actually guarantee that, in any of these test cases,
+  // epoll_wait will necessarily write out the epoll_events in the order that
+  // they were registered?
+  for (int i = 0; i < kFDsPerEpoll; i++) {
+    ASSERT_EQ(result[i].events, EPOLLOUT);
+  }
+}
+
+TEST(EpollTest, LastReadable) {
+  auto epollfd = ASSERT_NO_ERRNO_AND_VALUE(NewEpollFD());
+  std::vector<FileDescriptor> eventfds;
+  for (int i = 0; i < kFDsPerEpoll; i++) {
+    eventfds.push_back(ASSERT_NO_ERRNO_AND_VALUE(NewEventFD()));
+    ASSERT_NO_ERRNO(RegisterEpollFD(epollfd.get(), eventfds[i].get(),
+                                    EPOLLIN | EPOLLOUT, kMagicConstant + i));
+  }
+
+  uint64_t tmp = 1;
+  ASSERT_THAT(WriteFd(eventfds[kFDsPerEpoll - 1].get(), &tmp, sizeof(tmp)),
+              SyscallSucceedsWithValue(sizeof(tmp)));
+
+  struct epoll_event result[kFDsPerEpoll];
+  ASSERT_THAT(RetryEINTR(epoll_wait)(epollfd.get(), result, kFDsPerEpoll, -1),
+              SyscallSucceedsWithValue(kFDsPerEpoll));
+
+  int i;
+  for (i = 0; i < kFDsPerEpoll - 1; i++) {
+    EXPECT_EQ(result[i].events, EPOLLOUT);
+  }
+  EXPECT_EQ(result[i].events, EPOLLOUT | EPOLLIN);
+  EXPECT_EQ(result[i].data.u64, kMagicConstant + i);
+}
+
+TEST(EpollTest, LastNonWritable) {
+  auto epollfd = ASSERT_NO_ERRNO_AND_VALUE(NewEpollFD());
+  std::vector<FileDescriptor> eventfds;
+  for (int i = 0; i < kFDsPerEpoll; i++) {
+    eventfds.push_back(ASSERT_NO_ERRNO_AND_VALUE(NewEventFD()));
+    ASSERT_NO_ERRNO(RegisterEpollFD(epollfd.get(), eventfds[i].get(),
+                                    EPOLLIN | EPOLLOUT, kMagicConstant + i));
+  }
+
+  // Write the maximum value to the event fd so that writing to it again would
+  // block.
+  uint64_t tmp = ULLONG_MAX - 1;
+  ASSERT_THAT(WriteFd(eventfds[kFDsPerEpoll - 1].get(), &tmp, sizeof(tmp)),
+              SyscallSucceedsWithValue(sizeof(tmp)));
+
+  struct epoll_event result[kFDsPerEpoll];
+  ASSERT_THAT(RetryEINTR(epoll_wait)(epollfd.get(), result, kFDsPerEpoll, -1),
+              SyscallSucceedsWithValue(kFDsPerEpoll));
+
+  int i;
+  for (i = 0; i < kFDsPerEpoll - 1; i++) {
+    EXPECT_EQ(result[i].events, EPOLLOUT);
+  }
+  EXPECT_EQ(result[i].events, EPOLLIN);
+  EXPECT_THAT(ReadFd(eventfds[kFDsPerEpoll - 1].get(), &tmp, sizeof(tmp)),
+              sizeof(tmp));
+  EXPECT_THAT(RetryEINTR(epoll_wait)(epollfd.get(), result, kFDsPerEpoll, -1),
+              SyscallSucceedsWithValue(kFDsPerEpoll));
+
+  for (i = 0; i < kFDsPerEpoll; i++) {
+    EXPECT_EQ(result[i].events, EPOLLOUT);
+  }
+}
+
+TEST(EpollTest, Timeout_NoRandomSave) {
+  auto epollfd = ASSERT_NO_ERRNO_AND_VALUE(NewEpollFD());
+  std::vector<FileDescriptor> eventfds;
+  for (int i = 0; i < kFDsPerEpoll; i++) {
+    eventfds.push_back(ASSERT_NO_ERRNO_AND_VALUE(NewEventFD()));
+    ASSERT_NO_ERRNO(RegisterEpollFD(epollfd.get(), eventfds[i].get(), EPOLLIN,
+                                    kMagicConstant + i));
+  }
+
+  constexpr int kTimeoutMs = 200;
+  struct timespec begin;
+  struct timespec end;
+  struct epoll_event result[kFDsPerEpoll];
+
+  {
+    const DisableSave ds;  // Timing-related.
+    EXPECT_THAT(clock_gettime(CLOCK_MONOTONIC, &begin), SyscallSucceeds());
+
+    ASSERT_THAT(
+        RetryEINTR(epoll_wait)(epollfd.get(), result, kFDsPerEpoll, kTimeoutMs),
+        SyscallSucceedsWithValue(0));
+    EXPECT_THAT(clock_gettime(CLOCK_MONOTONIC, &end), SyscallSucceeds());
+  }
+
+  // Check the lower bound on the timeout.  Checking for an upper bound is
+  // fragile because Linux can overrun the timeout due to scheduling delays.
+  EXPECT_GT(ms_elapsed(&begin, &end), kTimeoutMs - 1);
+}
+
+void* writer(void* arg) {
+  int fd = *reinterpret_cast<int*>(arg);
+  uint64_t tmp = 1;
+
+  usleep(200000);
+  if (WriteFd(fd, &tmp, sizeof(tmp)) != sizeof(tmp)) {
+    fprintf(stderr, "writer failed: errno %s\n", strerror(errno));
+  }
+
+  return nullptr;
+}
+
+TEST(EpollTest, WaitThenUnblock) {
+  auto epollfd = ASSERT_NO_ERRNO_AND_VALUE(NewEpollFD());
+  std::vector<FileDescriptor> eventfds;
+  for (int i = 0; i < kFDsPerEpoll; i++) {
+    eventfds.push_back(ASSERT_NO_ERRNO_AND_VALUE(NewEventFD()));
+    ASSERT_NO_ERRNO(RegisterEpollFD(epollfd.get(), eventfds[i].get(), EPOLLIN,
+                                    kMagicConstant + i));
+  }
+
+  // Fire off a thread that will make at least one of the event fds readable.
+  pthread_t thread;
+  int make_readable = eventfds[0].get();
+  ASSERT_THAT(pthread_create(&thread, nullptr, writer, &make_readable),
+              SyscallSucceedsWithValue(0));
+
+  struct epoll_event result[kFDsPerEpoll];
+  EXPECT_THAT(RetryEINTR(epoll_wait)(epollfd.get(), result, kFDsPerEpoll, -1),
+              SyscallSucceedsWithValue(1));
+  EXPECT_THAT(pthread_detach(thread), SyscallSucceeds());
+}
+
+void sighandler(int s) {}
+
+void* signaler(void* arg) {
+  pthread_t* t = reinterpret_cast<pthread_t*>(arg);
+  // Repeatedly send the real-time signal until we are detached, because it's
+  // difficult to know exactly when epoll_wait on another thread (which this
+  // is intending to interrupt) has started blocking.
+  while (1) {
+    usleep(200000);
+    pthread_kill(*t, SIGRTMIN);
+  }
+  return nullptr;
+}
+
+TEST(EpollTest, UnblockWithSignal) {
+  auto epollfd = ASSERT_NO_ERRNO_AND_VALUE(NewEpollFD());
+  std::vector<FileDescriptor> eventfds;
+  for (int i = 0; i < kFDsPerEpoll; i++) {
+    eventfds.push_back(ASSERT_NO_ERRNO_AND_VALUE(NewEventFD()));
+    ASSERT_NO_ERRNO(RegisterEpollFD(epollfd.get(), eventfds[i].get(), EPOLLIN,
+                                    kMagicConstant + i));
+  }
+
+  signal(SIGRTMIN, sighandler);
+  // Unblock the real time signals that InitGoogle blocks :(
+  sigset_t unblock;
+  sigemptyset(&unblock);
+  sigaddset(&unblock, SIGRTMIN);
+  ASSERT_THAT(sigprocmask(SIG_UNBLOCK, &unblock, nullptr), SyscallSucceeds());
+
+  pthread_t thread;
+  pthread_t cur = pthread_self();
+  ASSERT_THAT(pthread_create(&thread, nullptr, signaler, &cur),
+              SyscallSucceedsWithValue(0));
+
+  struct epoll_event result[kFDsPerEpoll];
+  EXPECT_THAT(epoll_wait(epollfd.get(), result, kFDsPerEpoll, -1),
+              SyscallFailsWithErrno(EINTR));
+  EXPECT_THAT(pthread_cancel(thread), SyscallSucceeds());
+  EXPECT_THAT(pthread_detach(thread), SyscallSucceeds());
+}
+
+TEST(EpollTest, TimeoutNoFds) {
+  auto epollfd = ASSERT_NO_ERRNO_AND_VALUE(NewEpollFD());
+  struct epoll_event result[kFDsPerEpoll];
+  EXPECT_THAT(RetryEINTR(epoll_wait)(epollfd.get(), result, kFDsPerEpoll, 100),
+              SyscallSucceedsWithValue(0));
+}
+
+struct addr_ctx {
+  int epollfd;
+  int eventfd;
+};
+
+void* fd_adder(void* arg) {
+  struct addr_ctx* actx = reinterpret_cast<struct addr_ctx*>(arg);
+  struct epoll_event event;
+  event.events = EPOLLIN | EPOLLOUT;
+  event.data.u64 = 0xdeadbeeffacefeed;
+
+  usleep(200000);
+  if (epoll_ctl(actx->epollfd, EPOLL_CTL_ADD, actx->eventfd, &event) == -1) {
+    fprintf(stderr, "epoll_ctl failed: %s\n", strerror(errno));
+  }
+
+  return nullptr;
+}
+
+TEST(EpollTest, UnblockWithNewFD) {
+  auto epollfd = ASSERT_NO_ERRNO_AND_VALUE(NewEpollFD());
+  auto eventfd = ASSERT_NO_ERRNO_AND_VALUE(NewEventFD());
+
+  pthread_t thread;
+  struct addr_ctx actx = {epollfd.get(), eventfd.get()};
+  ASSERT_THAT(pthread_create(&thread, nullptr, fd_adder, &actx),
+              SyscallSucceedsWithValue(0));
+
+  struct epoll_event result[kFDsPerEpoll];
+  // Wait while no FDs are ready, but after 200ms fd_adder will add a ready FD
+  // to epoll which will wake us up.
+  EXPECT_THAT(RetryEINTR(epoll_wait)(epollfd.get(), result, kFDsPerEpoll, -1),
+              SyscallSucceedsWithValue(1));
+  EXPECT_THAT(pthread_detach(thread), SyscallSucceeds());
+  EXPECT_EQ(result[0].data.u64, 0xdeadbeeffacefeed);
+}
+
+TEST(EpollTest, Oneshot) {
+  auto epollfd = ASSERT_NO_ERRNO_AND_VALUE(NewEpollFD());
+  std::vector<FileDescriptor> eventfds;
+  for (int i = 0; i < kFDsPerEpoll; i++) {
+    eventfds.push_back(ASSERT_NO_ERRNO_AND_VALUE(NewEventFD()));
+    ASSERT_NO_ERRNO(RegisterEpollFD(epollfd.get(), eventfds[i].get(), EPOLLIN,
+                                    kMagicConstant + i));
+  }
+
+  struct epoll_event event;
+  event.events = EPOLLOUT | EPOLLONESHOT;
+  event.data.u64 = kMagicConstant;
+  ASSERT_THAT(
+      epoll_ctl(epollfd.get(), EPOLL_CTL_MOD, eventfds[0].get(), &event),
+      SyscallSucceeds());
+
+  struct epoll_event result[kFDsPerEpoll];
+  // One-shot entry means that the first epoll_wait should succeed.
+  ASSERT_THAT(RetryEINTR(epoll_wait)(epollfd.get(), result, kFDsPerEpoll, -1),
+              SyscallSucceedsWithValue(1));
+  EXPECT_EQ(result[0].data.u64, kMagicConstant);
+
+  // One-shot entry means that the second epoll_wait should timeout.
+  EXPECT_THAT(RetryEINTR(epoll_wait)(epollfd.get(), result, kFDsPerEpoll, 100),
+              SyscallSucceedsWithValue(0));
+}
+
+TEST(EpollTest, EdgeTriggered_NoRandomSave) {
+  // Test edge-triggered entry: make it edge-triggered, first wait should
+  // return it, second one should time out, make it writable again, third wait
+  // should return it, fourth wait should timeout.
+  auto epollfd = ASSERT_NO_ERRNO_AND_VALUE(NewEpollFD());
+  auto eventfd = ASSERT_NO_ERRNO_AND_VALUE(NewEventFD());
+  ASSERT_NO_ERRNO(RegisterEpollFD(epollfd.get(), eventfd.get(),
+                                  EPOLLOUT | EPOLLET, kMagicConstant));
+
+  struct epoll_event result[kFDsPerEpoll];
+
+  {
+    const DisableSave ds;  // May trigger spurious event.
+
+    // Edge-triggered entry means that the first epoll_wait should return the
+    // event.
+    ASSERT_THAT(epoll_wait(epollfd.get(), result, kFDsPerEpoll, -1),
+                SyscallSucceedsWithValue(1));
+    EXPECT_EQ(result[0].data.u64, kMagicConstant);
+
+    // Edge-triggered entry means that the second epoll_wait should time out.
+    ASSERT_THAT(epoll_wait(epollfd.get(), result, kFDsPerEpoll, 100),
+                SyscallSucceedsWithValue(0));
+  }
+
+  uint64_t tmp = ULLONG_MAX - 1;
+
+  // Make an fd non-writable.
+  ASSERT_THAT(WriteFd(eventfd.get(), &tmp, sizeof(tmp)),
+              SyscallSucceedsWithValue(sizeof(tmp)));
+
+  // Make the same fd non-writable to trigger a change, which will trigger an
+  // edge-triggered event.
+  ASSERT_THAT(ReadFd(eventfd.get(), &tmp, sizeof(tmp)),
+              SyscallSucceedsWithValue(sizeof(tmp)));
+
+  {
+    const DisableSave ds;  // May trigger spurious event.
+
+    // An edge-triggered event should now be returned.
+    ASSERT_THAT(epoll_wait(epollfd.get(), result, kFDsPerEpoll, -1),
+                SyscallSucceedsWithValue(1));
+    EXPECT_EQ(result[0].data.u64, kMagicConstant);
+
+    // The edge-triggered event had been consumed above, we don't expect to
+    // get it again.
+    ASSERT_THAT(epoll_wait(epollfd.get(), result, kFDsPerEpoll, 100),
+                SyscallSucceedsWithValue(0));
+  }
+}
+
+TEST(EpollTest, OneshotAndEdgeTriggered) {
+  auto epollfd = ASSERT_NO_ERRNO_AND_VALUE(NewEpollFD());
+  auto eventfd = ASSERT_NO_ERRNO_AND_VALUE(NewEventFD());
+  ASSERT_NO_ERRNO(RegisterEpollFD(epollfd.get(), eventfd.get(),
+                                  EPOLLOUT | EPOLLET | EPOLLONESHOT,
+                                  kMagicConstant));
+
+  struct epoll_event result[kFDsPerEpoll];
+  // First time one shot edge-triggered entry means that epoll_wait should
+  // return the event.
+  ASSERT_THAT(RetryEINTR(epoll_wait)(epollfd.get(), result, kFDsPerEpoll, -1),
+              SyscallSucceedsWithValue(1));
+  EXPECT_EQ(result[0].data.u64, kMagicConstant);
+
+  // Edge-triggered entry means that the second epoll_wait should time out.
+  ASSERT_THAT(RetryEINTR(epoll_wait)(epollfd.get(), result, kFDsPerEpoll, 100),
+              SyscallSucceedsWithValue(0));
+
+  uint64_t tmp = ULLONG_MAX - 1;
+  // Make an fd non-writable.
+  ASSERT_THAT(WriteFd(eventfd.get(), &tmp, sizeof(tmp)),
+              SyscallSucceedsWithValue(sizeof(tmp)));
+  // Make the same fd non-writable to trigger a change, which will not trigger
+  // an edge-triggered event because we've also included EPOLLONESHOT.
+  ASSERT_THAT(ReadFd(eventfd.get(), &tmp, sizeof(tmp)),
+              SyscallSucceedsWithValue(sizeof(tmp)));
+  ASSERT_THAT(RetryEINTR(epoll_wait)(epollfd.get(), result, kFDsPerEpoll, 100),
+              SyscallSucceedsWithValue(0));
+}
+
+TEST(EpollTest, CycleOfOneDisallowed) {
+  auto epollfd = ASSERT_NO_ERRNO_AND_VALUE(NewEpollFD());
+
+  struct epoll_event event;
+  event.events = EPOLLOUT;
+  event.data.u64 = kMagicConstant;
+
+  ASSERT_THAT(epoll_ctl(epollfd.get(), EPOLL_CTL_ADD, epollfd.get(), &event),
+              SyscallFailsWithErrno(EINVAL));
+}
+
+TEST(EpollTest, CycleOfThreeDisallowed) {
+  auto epollfd = ASSERT_NO_ERRNO_AND_VALUE(NewEpollFD());
+  auto epollfd1 = ASSERT_NO_ERRNO_AND_VALUE(NewEpollFD());
+  auto epollfd2 = ASSERT_NO_ERRNO_AND_VALUE(NewEpollFD());
+
+  ASSERT_NO_ERRNO(
+      RegisterEpollFD(epollfd.get(), epollfd1.get(), EPOLLIN, kMagicConstant));
+  ASSERT_NO_ERRNO(
+      RegisterEpollFD(epollfd1.get(), epollfd2.get(), EPOLLIN, kMagicConstant));
+
+  struct epoll_event event;
+  event.events = EPOLLIN;
+  event.data.u64 = kMagicConstant;
+  EXPECT_THAT(epoll_ctl(epollfd2.get(), EPOLL_CTL_ADD, epollfd.get(), &event),
+              SyscallFailsWithErrno(ELOOP));
+}
+
+TEST(EpollTest, CloseFile) {
+  auto epollfd = ASSERT_NO_ERRNO_AND_VALUE(NewEpollFD());
+  auto eventfd = ASSERT_NO_ERRNO_AND_VALUE(NewEventFD());
+  ASSERT_NO_ERRNO(
+      RegisterEpollFD(epollfd.get(), eventfd.get(), EPOLLOUT, kMagicConstant));
+
+  struct epoll_event result[kFDsPerEpoll];
+  ASSERT_THAT(RetryEINTR(epoll_wait)(epollfd.get(), result, kFDsPerEpoll, -1),
+              SyscallSucceedsWithValue(1));
+  EXPECT_EQ(result[0].data.u64, kMagicConstant);
+
+  // Close the event fd early.
+  eventfd.reset();
+
+  EXPECT_THAT(RetryEINTR(epoll_wait)(epollfd.get(), result, kFDsPerEpoll, 100),
+              SyscallSucceedsWithValue(0));
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor