gvisor/test/syscalls/linux/write.cc

341 lines
12 KiB
C++

// 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 <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <sys/mman.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "absl/base/macros.h"
#include "test/util/cleanup.h"
#include "test/util/temp_path.h"
#include "test/util/test_util.h"
namespace gvisor {
namespace testing {
namespace {
// TODO(gvisor.dev/issue/2370): This test is currently very rudimentary.
class WriteTest : public ::testing::Test {
public:
ssize_t WriteBytes(int fd, int bytes) {
std::vector<char> buf(bytes);
std::fill(buf.begin(), buf.end(), 'a');
return WriteFd(fd, buf.data(), buf.size());
}
};
TEST_F(WriteTest, WriteNoExceedsRLimit) {
// Get the current rlimit and restore after test run.
struct rlimit initial_lim;
ASSERT_THAT(getrlimit(RLIMIT_FSIZE, &initial_lim), SyscallSucceeds());
auto cleanup = Cleanup([&initial_lim] {
EXPECT_THAT(setrlimit(RLIMIT_FSIZE, &initial_lim), SyscallSucceeds());
});
int fd;
struct rlimit setlim;
const int target_lim = 1024;
setlim.rlim_cur = target_lim;
setlim.rlim_max = RLIM_INFINITY;
const std::string pathname = NewTempAbsPath();
ASSERT_THAT(fd = open(pathname.c_str(), O_WRONLY | O_CREAT, S_IRWXU),
SyscallSucceeds());
ASSERT_THAT(setrlimit(RLIMIT_FSIZE, &setlim), SyscallSucceeds());
EXPECT_THAT(WriteBytes(fd, target_lim), SyscallSucceedsWithValue(target_lim));
std::vector<char> buf(target_lim + 1);
std::fill(buf.begin(), buf.end(), 'a');
EXPECT_THAT(pwrite(fd, buf.data(), target_lim, 1), SyscallSucceeds());
EXPECT_THAT(pwrite64(fd, buf.data(), target_lim, 1), SyscallSucceeds());
EXPECT_THAT(close(fd), SyscallSucceeds());
}
TEST_F(WriteTest, WriteExceedsRLimit) {
// Get the current rlimit and restore after test run.
struct rlimit initial_lim;
ASSERT_THAT(getrlimit(RLIMIT_FSIZE, &initial_lim), SyscallSucceeds());
auto cleanup = Cleanup([&initial_lim] {
EXPECT_THAT(setrlimit(RLIMIT_FSIZE, &initial_lim), SyscallSucceeds());
});
int fd;
sigset_t filesize_mask;
sigemptyset(&filesize_mask);
sigaddset(&filesize_mask, SIGXFSZ);
struct rlimit setlim;
const int target_lim = 1024;
setlim.rlim_cur = target_lim;
setlim.rlim_max = RLIM_INFINITY;
const std::string pathname = NewTempAbsPath();
ASSERT_THAT(fd = open(pathname.c_str(), O_WRONLY | O_CREAT, S_IRWXU),
SyscallSucceeds());
ASSERT_THAT(setrlimit(RLIMIT_FSIZE, &setlim), SyscallSucceeds());
ASSERT_THAT(sigprocmask(SIG_BLOCK, &filesize_mask, nullptr),
SyscallSucceeds());
std::vector<char> buf(target_lim + 2);
std::fill(buf.begin(), buf.end(), 'a');
EXPECT_THAT(write(fd, buf.data(), target_lim + 1),
SyscallSucceedsWithValue(target_lim));
EXPECT_THAT(write(fd, buf.data(), 1), SyscallFailsWithErrno(EFBIG));
siginfo_t info;
struct timespec timelimit = {0, 0};
ASSERT_THAT(RetryEINTR(sigtimedwait)(&filesize_mask, &info, &timelimit),
SyscallSucceedsWithValue(SIGXFSZ));
EXPECT_EQ(info.si_code, SI_USER);
EXPECT_EQ(info.si_pid, getpid());
EXPECT_EQ(info.si_uid, getuid());
EXPECT_THAT(pwrite(fd, buf.data(), target_lim + 1, 1),
SyscallSucceedsWithValue(target_lim - 1));
EXPECT_THAT(pwrite(fd, buf.data(), 1, target_lim),
SyscallFailsWithErrno(EFBIG));
ASSERT_THAT(RetryEINTR(sigtimedwait)(&filesize_mask, &info, &timelimit),
SyscallSucceedsWithValue(SIGXFSZ));
EXPECT_EQ(info.si_code, SI_USER);
EXPECT_EQ(info.si_pid, getpid());
EXPECT_EQ(info.si_uid, getuid());
EXPECT_THAT(pwrite64(fd, buf.data(), target_lim + 1, 1),
SyscallSucceedsWithValue(target_lim - 1));
EXPECT_THAT(pwrite64(fd, buf.data(), 1, target_lim),
SyscallFailsWithErrno(EFBIG));
ASSERT_THAT(RetryEINTR(sigtimedwait)(&filesize_mask, &info, &timelimit),
SyscallSucceedsWithValue(SIGXFSZ));
EXPECT_EQ(info.si_code, SI_USER);
EXPECT_EQ(info.si_pid, getpid());
EXPECT_EQ(info.si_uid, getuid());
ASSERT_THAT(sigprocmask(SIG_UNBLOCK, &filesize_mask, nullptr),
SyscallSucceeds());
EXPECT_THAT(close(fd), SyscallSucceeds());
}
TEST_F(WriteTest, WriteIncrementOffset) {
TempPath tmpfile = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
FileDescriptor f =
ASSERT_NO_ERRNO_AND_VALUE(Open(tmpfile.path().c_str(), O_WRONLY));
int fd = f.get();
EXPECT_THAT(WriteBytes(fd, 0), SyscallSucceedsWithValue(0));
EXPECT_THAT(lseek(fd, 0, SEEK_CUR), SyscallSucceedsWithValue(0));
const int bytes_total = 1024;
EXPECT_THAT(WriteBytes(fd, bytes_total),
SyscallSucceedsWithValue(bytes_total));
EXPECT_THAT(lseek(fd, 0, SEEK_CUR), SyscallSucceedsWithValue(bytes_total));
}
TEST_F(WriteTest, WriteIncrementOffsetSeek) {
const std::string data = "hello world\n";
TempPath tmpfile = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
GetAbsoluteTestTmpdir(), data, TempPath::kDefaultFileMode));
FileDescriptor f =
ASSERT_NO_ERRNO_AND_VALUE(Open(tmpfile.path().c_str(), O_WRONLY));
int fd = f.get();
const int seek_offset = data.size() / 2;
ASSERT_THAT(lseek(fd, seek_offset, SEEK_SET),
SyscallSucceedsWithValue(seek_offset));
const int write_bytes = 512;
EXPECT_THAT(WriteBytes(fd, write_bytes),
SyscallSucceedsWithValue(write_bytes));
EXPECT_THAT(lseek(fd, 0, SEEK_CUR),
SyscallSucceedsWithValue(seek_offset + write_bytes));
}
TEST_F(WriteTest, WriteIncrementOffsetAppend) {
const std::string data = "hello world\n";
TempPath tmpfile = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
GetAbsoluteTestTmpdir(), data, TempPath::kDefaultFileMode));
FileDescriptor f = ASSERT_NO_ERRNO_AND_VALUE(
Open(tmpfile.path().c_str(), O_WRONLY | O_APPEND));
int fd = f.get();
EXPECT_THAT(WriteBytes(fd, 1024), SyscallSucceedsWithValue(1024));
EXPECT_THAT(lseek(fd, 0, SEEK_CUR),
SyscallSucceedsWithValue(data.size() + 1024));
}
TEST_F(WriteTest, WriteIncrementOffsetEOF) {
const std::string data = "hello world\n";
const TempPath tmpfile = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
GetAbsoluteTestTmpdir(), data, TempPath::kDefaultFileMode));
FileDescriptor f =
ASSERT_NO_ERRNO_AND_VALUE(Open(tmpfile.path().c_str(), O_WRONLY));
int fd = f.get();
EXPECT_THAT(lseek(fd, 0, SEEK_END), SyscallSucceedsWithValue(data.size()));
EXPECT_THAT(WriteBytes(fd, 1024), SyscallSucceedsWithValue(1024));
EXPECT_THAT(lseek(fd, 0, SEEK_END),
SyscallSucceedsWithValue(data.size() + 1024));
}
TEST_F(WriteTest, PwriteNoChangeOffset) {
TempPath tmpfile = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
FileDescriptor f =
ASSERT_NO_ERRNO_AND_VALUE(Open(tmpfile.path().c_str(), O_WRONLY));
int fd = f.get();
const std::string data = "hello world\n";
EXPECT_THAT(pwrite(fd, data.data(), data.size(), 0),
SyscallSucceedsWithValue(data.size()));
EXPECT_THAT(lseek(fd, 0, SEEK_CUR), SyscallSucceedsWithValue(0));
const int bytes_total = 1024;
ASSERT_THAT(WriteBytes(fd, bytes_total),
SyscallSucceedsWithValue(bytes_total));
ASSERT_THAT(lseek(fd, 0, SEEK_CUR), SyscallSucceedsWithValue(bytes_total));
EXPECT_THAT(pwrite(fd, data.data(), data.size(), bytes_total),
SyscallSucceedsWithValue(data.size()));
EXPECT_THAT(lseek(fd, 0, SEEK_CUR), SyscallSucceedsWithValue(bytes_total));
}
TEST_F(WriteTest, WriteWithOpath) {
SKIP_IF(IsRunningWithVFS1());
TempPath tmpfile = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
FileDescriptor f =
ASSERT_NO_ERRNO_AND_VALUE(Open(tmpfile.path().c_str(), O_PATH));
int fd = f.get();
EXPECT_THAT(WriteBytes(fd, 1024), SyscallFailsWithErrno(EBADF));
}
TEST_F(WriteTest, WritevWithOpath) {
SKIP_IF(IsRunningWithVFS1());
TempPath tmpfile = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
FileDescriptor f =
ASSERT_NO_ERRNO_AND_VALUE(Open(tmpfile.path().c_str(), O_PATH));
int fd = f.get();
char buf[16];
struct iovec iov;
iov.iov_base = buf;
iov.iov_len = sizeof(buf);
EXPECT_THAT(writev(fd, &iov, /*__count=*/1), SyscallFailsWithErrno(EBADF));
}
TEST_F(WriteTest, PwriteWithOpath) {
SKIP_IF(IsRunningWithVFS1());
TempPath tmpfile = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
FileDescriptor f =
ASSERT_NO_ERRNO_AND_VALUE(Open(tmpfile.path().c_str(), O_PATH));
int fd = f.get();
const std::string data = "hello world\n";
EXPECT_THAT(pwrite(fd, data.data(), data.size(), 0),
SyscallFailsWithErrno(EBADF));
}
// Test that partial writes that hit SIGSEGV are correctly handled and return
// partial write.
TEST_F(WriteTest, PartialWriteSIGSEGV) {
// Allocate 2 pages and remove permission from the second.
const size_t size = 2 * kPageSize;
void* addr = mmap(0, size, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
ASSERT_NE(addr, MAP_FAILED);
auto cleanup = Cleanup(
[addr, size] { EXPECT_THAT(munmap(addr, size), SyscallSucceeds()); });
void* badAddr = reinterpret_cast<char*>(addr) + kPageSize;
ASSERT_THAT(mprotect(badAddr, kPageSize, PROT_NONE), SyscallSucceeds());
TempPath file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
FileDescriptor fd =
ASSERT_NO_ERRNO_AND_VALUE(Open(file.path().c_str(), O_WRONLY));
// Attempt to write both pages to the file. 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,
},
};
// Write should succeed for the first iovec and half of the second (=2 pages).
EXPECT_THAT(pwritev(fd.get(), iov, ABSL_ARRAYSIZE(iov), 0),
SyscallSucceedsWithValue(2 * kPageSize));
}
// Test that partial writes that hit SIGBUS are correctly handled and return
// partial write.
TEST_F(WriteTest, PartialWriteSIGBUS) {
SKIP_IF(getenv("GVISOR_GOFER_UNCACHED")); // Can't mmap from uncached files.
TempPath mapfile = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
FileDescriptor fd_map =
ASSERT_NO_ERRNO_AND_VALUE(Open(mapfile.path().c_str(), O_RDWR));
// Let the first page be read to force a partial write.
ASSERT_THAT(ftruncate(fd_map.get(), kPageSize), SyscallSucceeds());
// Map 2 pages, one of which is not allocated in the backing file. Reading
// from it will trigger a SIGBUS.
const size_t size = 2 * kPageSize;
void* addr =
mmap(NULL, size, PROT_READ, MAP_FILE | MAP_PRIVATE, fd_map.get(), 0);
ASSERT_NE(addr, MAP_FAILED);
auto cleanup = Cleanup(
[addr, size] { EXPECT_THAT(munmap(addr, size), SyscallSucceeds()); });
TempPath file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
FileDescriptor fd =
ASSERT_NO_ERRNO_AND_VALUE(Open(file.path().c_str(), O_WRONLY));
// Attempt to write both pages to the file. 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,
},
};
// Write should succeed for the first iovec and half of the second (=2 pages).
ASSERT_THAT(pwritev(fd.get(), iov, ABSL_ARRAYSIZE(iov), 0),
SyscallSucceedsWithValue(2 * kPageSize));
}
} // namespace
} // namespace testing
} // namespace gvisor