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Diffstat (limited to 'test/syscalls/linux/shm.cc')
| -rw-r--r-- | test/syscalls/linux/shm.cc | 445 |
1 files changed, 445 insertions, 0 deletions
diff --git a/test/syscalls/linux/shm.cc b/test/syscalls/linux/shm.cc new file mode 100644 index 000000000..9f57476c9 --- /dev/null +++ b/test/syscalls/linux/shm.cc @@ -0,0 +1,445 @@ +// 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 <stdio.h> + +#include <sys/ipc.h> +#include <sys/mman.h> +#include <sys/shm.h> +#include <sys/types.h> + +#include "absl/time/clock.h" +#include "test/util/multiprocess_util.h" +#include "test/util/posix_error.h" +#include "test/util/temp_path.h" +#include "test/util/test_util.h" + +namespace gvisor { +namespace testing { +namespace { + +using ::testing::_; + +const uint64_t kAllocSize = kPageSize * 128ULL; + +PosixErrorOr<int> Shmget(key_t key, size_t size, int shmflg) { + int id = shmget(key, size, shmflg); + if (id == -1) { + return PosixError(errno, "shmget() failed"); + } + return id; +} + +PosixErrorOr<char*> Shmat(int shmid, const void* shmaddr, int shmflg) { + const intptr_t addr = + reinterpret_cast<intptr_t>(shmat(shmid, shmaddr, shmflg)); + if (addr == -1) { + return PosixError(errno, "shmat() failed"); + } + return reinterpret_cast<char*>(addr); +} + +PosixError Shmdt(const char* shmaddr) { + const int ret = shmdt(shmaddr); + if (ret == -1) { + return PosixError(errno, "shmdt() failed"); + } + return NoError(); +} + +template <typename T> +PosixErrorOr<int> Shmctl(int shmid, int cmd, T* buf) { + int ret = shmctl(shmid, cmd, reinterpret_cast<struct shmid_ds*>(buf)); + if (ret == -1) { + return PosixError(errno, "shmctl() failed"); + } + return ret; +} + +TEST(ShmTest, AttachDetach) { + const int id = ASSERT_NO_ERRNO_AND_VALUE( + Shmget(IPC_PRIVATE, kAllocSize, IPC_CREAT | 0777)); + struct shmid_ds attr; + ASSERT_NO_ERRNO(Shmctl(id, IPC_STAT, &attr)); + EXPECT_EQ(attr.shm_segsz, kAllocSize); + EXPECT_EQ(attr.shm_nattch, 0); + + const char* addr = ASSERT_NO_ERRNO_AND_VALUE(Shmat(id, nullptr, 0)); + ASSERT_NO_ERRNO(Shmctl(id, IPC_STAT, &attr)); + EXPECT_EQ(attr.shm_nattch, 1); + + const char* addr2 = ASSERT_NO_ERRNO_AND_VALUE(Shmat(id, nullptr, 0)); + ASSERT_NO_ERRNO(Shmctl(id, IPC_STAT, &attr)); + EXPECT_EQ(attr.shm_nattch, 2); + + ASSERT_NO_ERRNO(Shmdt(addr)); + ASSERT_NO_ERRNO(Shmctl(id, IPC_STAT, &attr)); + EXPECT_EQ(attr.shm_nattch, 1); + + ASSERT_NO_ERRNO(Shmdt(addr2)); + ASSERT_NO_ERRNO(Shmctl(id, IPC_STAT, &attr)); + EXPECT_EQ(attr.shm_nattch, 0); +} + +TEST(ShmTest, LookupByKey) { + const TempPath keyfile = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); + const key_t key = ftok(keyfile.path().c_str(), 1); + const int id = + ASSERT_NO_ERRNO_AND_VALUE(Shmget(key, kAllocSize, IPC_CREAT | 0777)); + const int id2 = ASSERT_NO_ERRNO_AND_VALUE(Shmget(key, kAllocSize, 0777)); + EXPECT_EQ(id, id2); +} + +TEST(ShmTest, DetachedSegmentsPersist) { + const int id = ASSERT_NO_ERRNO_AND_VALUE( + Shmget(IPC_PRIVATE, kAllocSize, IPC_CREAT | 0777)); + char* addr = ASSERT_NO_ERRNO_AND_VALUE(Shmat(id, nullptr, 0)); + addr[0] = 'x'; + ASSERT_NO_ERRNO(Shmdt(addr)); + + // We should be able to re-attach to the same segment and get our data back. + addr = ASSERT_NO_ERRNO_AND_VALUE(Shmat(id, nullptr, 0)); + EXPECT_EQ(addr[0], 'x'); + ASSERT_NO_ERRNO(Shmdt(addr)); +} + +TEST(ShmTest, MultipleDetachFails) { + const int id = ASSERT_NO_ERRNO_AND_VALUE( + Shmget(IPC_PRIVATE, kAllocSize, IPC_CREAT | 0777)); + const char* addr = ASSERT_NO_ERRNO_AND_VALUE(Shmat(id, nullptr, 0)); + ASSERT_NO_ERRNO(Shmdt(addr)); + EXPECT_THAT(Shmdt(addr), PosixErrorIs(EINVAL, _)); +} + +TEST(ShmTest, IpcStat) { + const TempPath keyfile = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); + const key_t key = ftok(keyfile.path().c_str(), 1); + + const time_t start = time(nullptr); + + const int id = + ASSERT_NO_ERRNO_AND_VALUE(Shmget(key, kAllocSize, IPC_CREAT | 0777)); + + const uid_t uid = getuid(); + const gid_t gid = getgid(); + const pid_t pid = getpid(); + + struct shmid_ds attr; + ASSERT_NO_ERRNO(Shmctl(id, IPC_STAT, &attr)); + + EXPECT_EQ(attr.shm_perm.__key, key); + EXPECT_EQ(attr.shm_perm.uid, uid); + EXPECT_EQ(attr.shm_perm.gid, gid); + EXPECT_EQ(attr.shm_perm.cuid, uid); + EXPECT_EQ(attr.shm_perm.cgid, gid); + EXPECT_EQ(attr.shm_perm.mode, 0777); + + EXPECT_EQ(attr.shm_segsz, kAllocSize); + + EXPECT_EQ(attr.shm_atime, 0); + EXPECT_EQ(attr.shm_dtime, 0); + + // Change time is set on creation. + EXPECT_GE(attr.shm_ctime, start); + + EXPECT_EQ(attr.shm_cpid, pid); + EXPECT_EQ(attr.shm_lpid, 0); + + EXPECT_EQ(attr.shm_nattch, 0); + + // The timestamps only have a resolution of seconds; slow down so we actually + // see the timestamps change. + absl::SleepFor(absl::Seconds(1)); + const time_t pre_attach = time(nullptr); + + const char* addr = ASSERT_NO_ERRNO_AND_VALUE(Shmat(id, nullptr, 0)); + ASSERT_NO_ERRNO(Shmctl(id, IPC_STAT, &attr)); + + EXPECT_GE(attr.shm_atime, pre_attach); + EXPECT_EQ(attr.shm_dtime, 0); + EXPECT_LT(attr.shm_ctime, pre_attach); + EXPECT_EQ(attr.shm_lpid, pid); + EXPECT_EQ(attr.shm_nattch, 1); + + absl::SleepFor(absl::Seconds(1)); + const time_t pre_detach = time(nullptr); + + ASSERT_NO_ERRNO(Shmdt(addr)); + ASSERT_NO_ERRNO(Shmctl(id, IPC_STAT, &attr)); + + EXPECT_LT(attr.shm_atime, pre_detach); + EXPECT_GE(attr.shm_dtime, pre_detach); + EXPECT_LT(attr.shm_ctime, pre_detach); + EXPECT_EQ(attr.shm_lpid, pid); + EXPECT_EQ(attr.shm_nattch, 0); +} + +TEST(ShmTest, ShmStat) { + // This test relies on the segment we create to be the first one on the + // system, causing it to occupy slot 1. We can't reasonably expect this on a + // general Linux host. + SKIP_IF(!IsRunningOnGvisor()); + + ASSERT_NO_ERRNO(Shmget(IPC_PRIVATE, kAllocSize, IPC_CREAT | 0777)); + struct shmid_ds attr; + ASSERT_NO_ERRNO(Shmctl(1, SHM_STAT, &attr)); + // This does the same thing as IPC_STAT, so only test that the syscall + // succeeds here. +} + +TEST(ShmTest, IpcInfo) { + struct shminfo info; + ASSERT_NO_ERRNO(Shmctl(0, IPC_INFO, &info)); + + EXPECT_EQ(info.shmmin, 1); // This is always 1, according to the man page. + EXPECT_GT(info.shmmax, info.shmmin); + EXPECT_GT(info.shmmni, 0); + EXPECT_GT(info.shmseg, 0); + EXPECT_GT(info.shmall, 0); +} + +TEST(ShmTest, ShmInfo) { + struct shm_info info; + + // We generally can't know what other processes on a linux machine + // does with shared memory segments, so we can't test specific + // numbers on Linux. When running under gvisor, we're guaranteed to + // be the only ones using shm, so we can easily verify machine-wide + // numbers. + if (IsRunningOnGvisor()) { + ASSERT_NO_ERRNO(Shmctl(0, SHM_INFO, &info)); + EXPECT_EQ(info.used_ids, 0); + EXPECT_EQ(info.shm_tot, 0); + EXPECT_EQ(info.shm_rss, 0); + EXPECT_EQ(info.shm_swp, 0); + } + + const int id = ASSERT_NO_ERRNO_AND_VALUE( + Shmget(IPC_PRIVATE, kAllocSize, IPC_CREAT | 0777)); + const char* addr = ASSERT_NO_ERRNO_AND_VALUE(Shmat(id, nullptr, 0)); + + ASSERT_NO_ERRNO(Shmctl(1, SHM_INFO, &info)); + + if (IsRunningOnGvisor()) { + ASSERT_NO_ERRNO(Shmctl(id, SHM_INFO, &info)); + EXPECT_EQ(info.used_ids, 1); + EXPECT_EQ(info.shm_tot, kAllocSize / kPageSize); + EXPECT_EQ(info.shm_rss, kAllocSize / kPageSize); + EXPECT_EQ(info.shm_swp, 0); // Gvisor currently never swaps. + } + + ASSERT_NO_ERRNO(Shmdt(addr)); +} + +TEST(ShmTest, ShmCtlSet) { + const int id = ASSERT_NO_ERRNO_AND_VALUE( + Shmget(IPC_PRIVATE, kAllocSize, IPC_CREAT | 0777)); + const char* addr = ASSERT_NO_ERRNO_AND_VALUE(Shmat(id, nullptr, 0)); + + struct shmid_ds attr; + ASSERT_NO_ERRNO(Shmctl(id, IPC_STAT, &attr)); + ASSERT_EQ(attr.shm_perm.mode, 0777); + + attr.shm_perm.mode = 0766; + ASSERT_NO_ERRNO(Shmctl(id, IPC_SET, &attr)); + + ASSERT_NO_ERRNO(Shmctl(id, IPC_STAT, &attr)); + ASSERT_EQ(attr.shm_perm.mode, 0766); + + ASSERT_NO_ERRNO(Shmdt(addr)); +} + +TEST(ShmTest, RemovedSegmentsAreMarkedDeleted) { + const int id = ASSERT_NO_ERRNO_AND_VALUE( + Shmget(IPC_PRIVATE, kAllocSize, IPC_CREAT | 0777)); + const char* addr = ASSERT_NO_ERRNO_AND_VALUE(Shmat(id, nullptr, 0)); + ASSERT_NO_ERRNO(Shmctl<void>(id, IPC_RMID, nullptr)); + struct shmid_ds attr; + ASSERT_NO_ERRNO(Shmctl(id, IPC_STAT, &attr)); + EXPECT_NE(attr.shm_perm.mode & SHM_DEST, 0); + ASSERT_NO_ERRNO(Shmdt(addr)); +} + +TEST(ShmTest, RemovedSegmentsAreDestroyed) { + const int id = ASSERT_NO_ERRNO_AND_VALUE( + Shmget(IPC_PRIVATE, kAllocSize, IPC_CREAT | 0777)); + const char* addr = ASSERT_NO_ERRNO_AND_VALUE(Shmat(id, nullptr, 0)); + + const uint64_t alloc_pages = kAllocSize / kPageSize; + + struct shm_info info; + ASSERT_NO_ERRNO(Shmctl(1, SHM_INFO, &info)); + const uint64_t before = info.shm_tot; + + ASSERT_NO_ERRNO(Shmctl<void>(id, IPC_RMID, nullptr)); + ASSERT_NO_ERRNO(Shmdt(addr)); + + ASSERT_NO_ERRNO(Shmctl(1, SHM_INFO, &info)); + const uint64_t after = info.shm_tot; + EXPECT_EQ(after, before - alloc_pages); +} + +TEST(ShmTest, AllowsAttachToRemovedSegmentWithRefs) { + const int id = ASSERT_NO_ERRNO_AND_VALUE( + Shmget(IPC_PRIVATE, kAllocSize, IPC_CREAT | 0777)); + const char* addr = ASSERT_NO_ERRNO_AND_VALUE(Shmat(id, nullptr, 0)); + ASSERT_NO_ERRNO(Shmctl<void>(id, IPC_RMID, nullptr)); + const char* addr2 = ASSERT_NO_ERRNO_AND_VALUE(Shmat(id, nullptr, 0)); + ASSERT_NO_ERRNO(Shmdt(addr)); + ASSERT_NO_ERRNO(Shmdt(addr2)); +} + +TEST(ShmTest, RemovedSegmentsAreNotDiscoverable) { + const TempPath keyfile = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); + const key_t key = ftok(keyfile.path().c_str(), 1); + const int id = + ASSERT_NO_ERRNO_AND_VALUE(Shmget(key, kAllocSize, IPC_CREAT | 0777)); + ASSERT_NO_ERRNO(Shmctl<void>(id, IPC_RMID, nullptr)); + EXPECT_THAT(Shmget(key, kAllocSize, 0777), PosixErrorIs(ENOENT, _)); +} + +TEST(ShmDeathTest, ReadonlySegment) { + SetupGvisorDeathTest(); + const int id = ASSERT_NO_ERRNO_AND_VALUE( + Shmget(IPC_PRIVATE, kAllocSize, IPC_CREAT | 0777)); + char* addr = ASSERT_NO_ERRNO_AND_VALUE(Shmat(id, nullptr, SHM_RDONLY)); + // Reading succeeds. + static_cast<void>(addr[0]); + // Writing fails. + EXPECT_EXIT(addr[0] = 'x', ::testing::KilledBySignal(SIGSEGV), ""); +} + +TEST(ShmDeathTest, SegmentNotAccessibleAfterDetach) { + // This test is susceptible to races with concurrent mmaps running in parallel + // gtest threads since the test relies on the address freed during a shm + // segment destruction to remain unused. We run the test body in a forked + // child to guarantee a single-threaded context to avoid this. + + SetupGvisorDeathTest(); + + const auto rest = [&] { + const int id = ASSERT_NO_ERRNO_AND_VALUE( + Shmget(IPC_PRIVATE, kAllocSize, IPC_CREAT | 0777)); + char* addr = ASSERT_NO_ERRNO_AND_VALUE(Shmat(id, nullptr, 0)); + addr[0] = 'x'; + ASSERT_NO_ERRNO(Shmdt(addr)); + + // This access should cause a SIGSEGV. + addr[0] = 'x'; + }; + + EXPECT_THAT(InForkedProcess(rest), + IsPosixErrorOkAndHolds(W_EXITCODE(0, SIGSEGV))); +} + +TEST(ShmTest, RequestingSegmentSmallerThanSHMMINFails) { + struct shminfo info; + ASSERT_NO_ERRNO(Shmctl(0, IPC_INFO, &info)); + const uint64_t size = info.shmmin - 1; + EXPECT_THAT(Shmget(IPC_PRIVATE, size, IPC_CREAT | 0777), + PosixErrorIs(EINVAL, _)); +} + +TEST(ShmTest, RequestingSegmentLargerThanSHMMAXFails) { + struct shminfo info; + ASSERT_NO_ERRNO(Shmctl(0, IPC_INFO, &info)); + const uint64_t size = info.shmmax + kPageSize; + EXPECT_THAT(Shmget(IPC_PRIVATE, size, IPC_CREAT | 0777), + PosixErrorIs(EINVAL, _)); +} + +TEST(ShmTest, RequestingUnalignedSizeSucceeds) { + EXPECT_NO_ERRNO(Shmget(IPC_PRIVATE, 4097, IPC_CREAT | 0777)); +} + +TEST(ShmTest, RequestingDuplicateCreationFails) { + const TempPath keyfile = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); + const key_t key = ftok(keyfile.path().c_str(), 1); + ASSERT_NO_ERRNO_AND_VALUE( + Shmget(key, kAllocSize, IPC_CREAT | IPC_EXCL | 0777)); + EXPECT_THAT(Shmget(key, kAllocSize, IPC_CREAT | IPC_EXCL | 0777), + PosixErrorIs(EEXIST, _)); +} + +TEST(ShmTest, SegmentsSizeFixedOnCreation) { + const TempPath keyfile = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); + const key_t key = ftok(keyfile.path().c_str(), 1); + + // Base segment. + const int id = + ASSERT_NO_ERRNO_AND_VALUE(Shmget(key, kAllocSize, IPC_CREAT | 0777)); + + // Ask for the same segment at half size. This succeeds. + const int id2 = ASSERT_NO_ERRNO_AND_VALUE(Shmget(key, kAllocSize / 2, 0777)); + + // Ask for the same segment at double size. + EXPECT_THAT(Shmget(key, kAllocSize * 2, 0777), PosixErrorIs(EINVAL, _)); + + char* addr = ASSERT_NO_ERRNO_AND_VALUE(Shmat(id, nullptr, 0)); + char* addr2 = ASSERT_NO_ERRNO_AND_VALUE(Shmat(id2, nullptr, 0)); + + // We have 2 different maps... + EXPECT_NE(addr, addr2); + + // ... And both maps are kAllocSize bytes; despite asking for a half-sized + // segment for the second map. + addr[kAllocSize - 1] = 'x'; + addr2[kAllocSize - 1] = 'x'; + + ASSERT_NO_ERRNO(Shmdt(addr)); + ASSERT_NO_ERRNO(Shmdt(addr2)); +} + +TEST(ShmTest, PartialUnmap) { + const int id = ASSERT_NO_ERRNO_AND_VALUE( + Shmget(IPC_PRIVATE, kAllocSize, IPC_CREAT | 0777)); + char* addr = ASSERT_NO_ERRNO_AND_VALUE(Shmat(id, nullptr, 0)); + EXPECT_THAT(munmap(addr + (kAllocSize / 4), kAllocSize / 2), + SyscallSucceeds()); + ASSERT_NO_ERRNO(Shmdt(addr)); +} + +// Check that sentry does not panic when asked for a zero-length private shm +// segment. +TEST(ShmTest, GracefullyFailOnZeroLenSegmentCreation) { + EXPECT_THAT(Shmget(IPC_PRIVATE, 0, 0), PosixErrorIs(EINVAL, _)); +} + +TEST(ShmTest, NoDestructionOfAttachedSegmentWithMultipleRmid) { + const int id = ASSERT_NO_ERRNO_AND_VALUE( + Shmget(IPC_PRIVATE, kAllocSize, IPC_CREAT | 0777)); + char* addr = ASSERT_NO_ERRNO_AND_VALUE(Shmat(id, nullptr, 0)); + char* addr2 = ASSERT_NO_ERRNO_AND_VALUE(Shmat(id, nullptr, 0)); + + // There should be 2 refs to the segment from the 2 attachments, and a single + // self-reference. Mark the segment as destroyed more than 3 times through + // shmctl(RMID). If there's a bug with the ref counting, this should cause the + // count to drop to zero. + for (int i = 0; i < 6; ++i) { + ASSERT_NO_ERRNO(Shmctl<void>(id, IPC_RMID, nullptr)); + } + + // Segment should remain accessible. + addr[0] = 'x'; + ASSERT_NO_ERRNO(Shmdt(addr)); + + // Segment should remain accessible even after one of the two attachments are + // detached. + addr2[0] = 'x'; + ASSERT_NO_ERRNO(Shmdt(addr2)); +} + +} // namespace +} // namespace testing +} // namespace gvisor |