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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/mman.h>
#include <unistd.h>
#include <vector>
#include "gtest/gtest.h"
#include "absl/base/macros.h"
#include "test/util/cleanup.h"
#include "test/util/file_descriptor.h"
#include "test/util/temp_path.h"
#include "test/util/test_util.h"
namespace gvisor {
namespace testing {
namespace {
class ReadTest : public ::testing::Test {
void SetUp() override {
name_ = NewTempAbsPath();
int fd;
ASSERT_THAT(fd = open(name_.c_str(), O_CREAT, 0644), SyscallSucceeds());
ASSERT_THAT(close(fd), SyscallSucceeds());
}
void TearDown() override { unlink(name_.c_str()); }
public:
std::string name_;
};
TEST_F(ReadTest, ZeroBuffer) {
int fd;
ASSERT_THAT(fd = open(name_.c_str(), O_RDWR), SyscallSucceeds());
char msg[] = "hello world";
EXPECT_THAT(PwriteFd(fd, msg, strlen(msg), 0),
SyscallSucceedsWithValue(strlen(msg)));
char buf[10];
EXPECT_THAT(ReadFd(fd, buf, 0), SyscallSucceedsWithValue(0));
EXPECT_THAT(close(fd), SyscallSucceeds());
}
TEST_F(ReadTest, EmptyFileReturnsZeroAtEOF) {
int fd;
ASSERT_THAT(fd = open(name_.c_str(), O_RDWR), SyscallSucceeds());
char eof_buf[10];
EXPECT_THAT(ReadFd(fd, eof_buf, 10), SyscallSucceedsWithValue(0));
EXPECT_THAT(close(fd), SyscallSucceeds());
}
TEST_F(ReadTest, EofAfterRead) {
int fd;
ASSERT_THAT(fd = open(name_.c_str(), O_RDWR), SyscallSucceeds());
// Write some bytes to be read.
constexpr char kMessage[] = "hello world";
EXPECT_THAT(PwriteFd(fd, kMessage, sizeof(kMessage), 0),
SyscallSucceedsWithValue(sizeof(kMessage)));
// Read all of the bytes at once.
char buf[sizeof(kMessage)];
EXPECT_THAT(ReadFd(fd, buf, sizeof(kMessage)),
SyscallSucceedsWithValue(sizeof(kMessage)));
// Read again with a non-zero buffer and expect EOF.
char eof_buf[10];
EXPECT_THAT(ReadFd(fd, eof_buf, 10), SyscallSucceedsWithValue(0));
EXPECT_THAT(close(fd), SyscallSucceeds());
}
TEST_F(ReadTest, DevNullReturnsEof) {
int fd;
ASSERT_THAT(fd = open("/dev/null", O_RDONLY), SyscallSucceeds());
std::vector<char> buf(1);
EXPECT_THAT(ReadFd(fd, buf.data(), 1), SyscallSucceedsWithValue(0));
EXPECT_THAT(close(fd), SyscallSucceeds());
}
const int kReadSize = 128 * 1024;
// Do not allow random save as it could lead to partial reads.
TEST_F(ReadTest, CanReadFullyFromDevZero_NoRandomSave) {
int fd;
ASSERT_THAT(fd = open("/dev/zero", O_RDONLY), SyscallSucceeds());
std::vector<char> buf(kReadSize, 1);
EXPECT_THAT(ReadFd(fd, buf.data(), kReadSize),
SyscallSucceedsWithValue(kReadSize));
EXPECT_THAT(close(fd), SyscallSucceeds());
EXPECT_EQ(std::vector<char>(kReadSize, 0), buf);
}
TEST_F(ReadTest, ReadDirectoryFails) {
const FileDescriptor file =
ASSERT_NO_ERRNO_AND_VALUE(Open(GetAbsoluteTestTmpdir(), O_RDONLY));
std::vector<char> buf(1);
EXPECT_THAT(ReadFd(file.get(), buf.data(), 1), SyscallFailsWithErrno(EISDIR));
}
TEST_F(ReadTest, ReadWithOpath) {
SKIP_IF(IsRunningWithVFS1());
const TempPath file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
const FileDescriptor fd =
ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_PATH));
std::vector<char> buf(1);
EXPECT_THAT(ReadFd(fd.get(), buf.data(), 1), SyscallFailsWithErrno(EBADF));
}
// Test that partial writes that hit SIGSEGV are correctly handled and return
// partial write.
TEST_F(ReadTest, PartialReadSIGSEGV) {
// Allocate 2 pages and remove permission from the second.
const size_t size = 2 * kPageSize;
void* addr =
mmap(0, size, PROT_WRITE | PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
ASSERT_NE(addr, MAP_FAILED);
auto cleanup = Cleanup(
[addr, size] { EXPECT_THAT(munmap(addr, size), SyscallSucceeds()); });
FileDescriptor fd =
ASSERT_NO_ERRNO_AND_VALUE(Open(name_.c_str(), O_RDWR, 0666));
for (size_t i = 0; i < 2; i++) {
EXPECT_THAT(pwrite(fd.get(), addr, size, 0),
SyscallSucceedsWithValue(size));
}
void* badAddr = reinterpret_cast<char*>(addr) + kPageSize;
ASSERT_THAT(mprotect(badAddr, kPageSize, PROT_NONE), SyscallSucceeds());
// Attempt to read to both pages. Create a non-contiguous iovec pair to
// ensure operation is done in 2 steps.
struct iovec iov[] = {
{
.iov_base = addr,
.iov_len = kPageSize,
},
{
.iov_base = addr,
.iov_len = size,
},
};
EXPECT_THAT(preadv(fd.get(), iov, ABSL_ARRAYSIZE(iov), 0),
SyscallSucceedsWithValue(size));
}
} // namespace
} // namespace testing
} // namespace gvisor
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