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// 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 <sys/resource.h>
#include <unistd.h>
#include "gtest/gtest.h"
#include "absl/memory/memory.h"
#include "test/util/eventfd_util.h"
#include "test/util/file_descriptor.h"
#include "test/util/fs_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 {
PosixErrorOr<FileDescriptor> Dup2(const FileDescriptor& fd, int target_fd) {
int new_fd = dup2(fd.get(), target_fd);
if (new_fd < 0) {
return PosixError(errno, "Dup2");
}
return FileDescriptor(new_fd);
}
PosixErrorOr<FileDescriptor> Dup3(const FileDescriptor& fd, int target_fd,
int flags) {
int new_fd = dup3(fd.get(), target_fd, flags);
if (new_fd < 0) {
return PosixError(errno, "Dup2");
}
return FileDescriptor(new_fd);
}
TEST(DupTest, Dup) {
auto f = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(f.path(), O_RDONLY));
// Dup the descriptor and make sure it's the same file.
FileDescriptor nfd = ASSERT_NO_ERRNO_AND_VALUE(fd.Dup());
ASSERT_NE(fd.get(), nfd.get());
ASSERT_NO_ERRNO(CheckSameFile(fd, nfd));
}
TEST(DupTest, DupClearsCloExec) {
// Open an eventfd file descriptor with FD_CLOEXEC descriptor flag set.
FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(NewEventFD(0, EFD_CLOEXEC));
EXPECT_THAT(fcntl(fd.get(), F_GETFD), SyscallSucceedsWithValue(FD_CLOEXEC));
// Duplicate the descriptor. Ensure that it doesn't have FD_CLOEXEC set.
FileDescriptor nfd = ASSERT_NO_ERRNO_AND_VALUE(fd.Dup());
ASSERT_NE(fd.get(), nfd.get());
ASSERT_NO_ERRNO(CheckSameFile(fd, nfd));
EXPECT_THAT(fcntl(nfd.get(), F_GETFD), SyscallSucceedsWithValue(0));
}
TEST(DupTest, DupWithOpath) {
SKIP_IF(IsRunningWithVFS1());
auto f = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(f.path(), O_PATH));
int flags;
ASSERT_THAT(flags = fcntl(fd.get(), F_GETFL), SyscallSucceeds());
// Dup the descriptor and make sure it's the same file.
FileDescriptor nfd = ASSERT_NO_ERRNO_AND_VALUE(fd.Dup());
ASSERT_NE(fd.get(), nfd.get());
ASSERT_NO_ERRNO(CheckSameFile(fd, nfd));
EXPECT_THAT(fcntl(nfd.get(), F_GETFL), SyscallSucceedsWithValue(flags));
}
TEST(DupTest, Dup2) {
auto f = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(f.path(), O_RDONLY));
// Regular dup once.
FileDescriptor nfd = ASSERT_NO_ERRNO_AND_VALUE(fd.Dup());
ASSERT_NE(fd.get(), nfd.get());
ASSERT_NO_ERRNO(CheckSameFile(fd, nfd));
// Dup over the file above.
int target_fd = nfd.release();
FileDescriptor nfd2 = ASSERT_NO_ERRNO_AND_VALUE(Dup2(fd, target_fd));
EXPECT_EQ(target_fd, nfd2.get());
ASSERT_NO_ERRNO(CheckSameFile(fd, nfd2));
}
TEST(DupTest, Rlimit) {
constexpr int kFDLimit = 101;
auto f = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(f.path(), O_RDONLY));
struct rlimit rl = {};
EXPECT_THAT(getrlimit(RLIMIT_NOFILE, &rl), SyscallSucceeds());
// Lower the rlimit first, as it may be equal to /proc/sys/fs/nr_open, in
// which case even users with CAP_SYS_RESOURCE can't raise it.
rl.rlim_cur = kFDLimit * 2;
ASSERT_THAT(setrlimit(RLIMIT_NOFILE, &rl), SyscallSucceeds());
FileDescriptor aboveLimitFD =
ASSERT_NO_ERRNO_AND_VALUE(Dup2(fd, kFDLimit * 2 - 1));
rl.rlim_cur = kFDLimit;
ASSERT_THAT(setrlimit(RLIMIT_NOFILE, &rl), SyscallSucceeds());
ASSERT_THAT(dup3(fd.get(), kFDLimit, 0), SyscallFails());
std::vector<std::unique_ptr<FileDescriptor>> fds;
int prev = fd.get();
for (int i = 0; i < kFDLimit; i++) {
int d = dup(fd.get());
if (d == -1) {
break;
}
std::unique_ptr<FileDescriptor> f = absl::make_unique<FileDescriptor>(d);
EXPECT_LT(d, kFDLimit);
EXPECT_GT(d, prev);
prev = d;
fds.push_back(std::move(f));
}
EXPECT_EQ(fds.size(), kFDLimit - fd.get() - 1);
}
TEST(DupTest, Dup2SameFD) {
auto f = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(f.path(), O_RDONLY));
// Should succeed.
ASSERT_THAT(dup2(fd.get(), fd.get()), SyscallSucceedsWithValue(fd.get()));
}
TEST(DupTest, Dup2WithOpath) {
SKIP_IF(IsRunningWithVFS1());
auto f = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(f.path(), O_PATH));
int flags;
ASSERT_THAT(flags = fcntl(fd.get(), F_GETFL), SyscallSucceeds());
// Regular dup once.
FileDescriptor nfd = ASSERT_NO_ERRNO_AND_VALUE(fd.Dup());
ASSERT_NE(fd.get(), nfd.get());
ASSERT_NO_ERRNO(CheckSameFile(fd, nfd));
EXPECT_THAT(fcntl(nfd.get(), F_GETFL), SyscallSucceedsWithValue(flags));
// Dup over the file above.
int target_fd = nfd.release();
FileDescriptor nfd2 = ASSERT_NO_ERRNO_AND_VALUE(Dup2(fd, target_fd));
EXPECT_EQ(target_fd, nfd2.get());
ASSERT_NO_ERRNO(CheckSameFile(fd, nfd2));
EXPECT_THAT(fcntl(nfd2.get(), F_GETFL), SyscallSucceedsWithValue(flags));
}
TEST(DupTest, Dup3) {
auto f = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(f.path(), O_RDONLY));
// Regular dup once.
FileDescriptor nfd = ASSERT_NO_ERRNO_AND_VALUE(fd.Dup());
ASSERT_NE(fd.get(), nfd.get());
ASSERT_NO_ERRNO(CheckSameFile(fd, nfd));
// Dup over the file above, check that it has no CLOEXEC.
nfd = ASSERT_NO_ERRNO_AND_VALUE(Dup3(fd, nfd.release(), 0));
ASSERT_NO_ERRNO(CheckSameFile(fd, nfd));
EXPECT_THAT(fcntl(nfd.get(), F_GETFD), SyscallSucceedsWithValue(0));
// Dup over the file again, check that it does not CLOEXEC.
nfd = ASSERT_NO_ERRNO_AND_VALUE(Dup3(fd, nfd.release(), O_CLOEXEC));
ASSERT_NO_ERRNO(CheckSameFile(fd, nfd));
EXPECT_THAT(fcntl(nfd.get(), F_GETFD), SyscallSucceedsWithValue(FD_CLOEXEC));
}
TEST(DupTest, Dup3FailsSameFD) {
auto f = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(f.path(), O_RDONLY));
// Only dup3 fails if the new and old fd are the same.
ASSERT_THAT(dup3(fd.get(), fd.get(), 0), SyscallFailsWithErrno(EINVAL));
}
TEST(DupTest, Dup3WithOpath) {
SKIP_IF(IsRunningWithVFS1());
auto f = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(f.path(), O_PATH));
EXPECT_THAT(fcntl(fd.get(), F_GETFD), SyscallSucceedsWithValue(0));
int flags;
ASSERT_THAT(flags = fcntl(fd.get(), F_GETFL), SyscallSucceeds());
// Regular dup once.
FileDescriptor nfd = ASSERT_NO_ERRNO_AND_VALUE(fd.Dup());
ASSERT_NE(fd.get(), nfd.get());
ASSERT_NO_ERRNO(CheckSameFile(fd, nfd));
// Dup over the file above, check that it has no CLOEXEC.
nfd = ASSERT_NO_ERRNO_AND_VALUE(Dup3(fd, nfd.release(), 0));
ASSERT_NO_ERRNO(CheckSameFile(fd, nfd));
EXPECT_THAT(fcntl(nfd.get(), F_GETFD), SyscallSucceedsWithValue(0));
EXPECT_THAT(fcntl(nfd.get(), F_GETFL), SyscallSucceedsWithValue(flags));
// Dup over the file again, check that it does not CLOEXEC.
nfd = ASSERT_NO_ERRNO_AND_VALUE(Dup3(fd, nfd.release(), O_CLOEXEC));
ASSERT_NO_ERRNO(CheckSameFile(fd, nfd));
EXPECT_THAT(fcntl(nfd.get(), F_GETFD), SyscallSucceedsWithValue(FD_CLOEXEC));
EXPECT_THAT(fcntl(nfd.get(), F_GETFL), SyscallSucceedsWithValue(flags));
}
} // namespace
} // namespace testing
} // namespace gvisor
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