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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 <errno.h>
#include <signal.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/vfs.h>
#include <time.h>
#include <unistd.h>
#include <iostream>
#include <string>
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "absl/strings/string_view.h"
#include "test/syscalls/linux/file_base.h"
#include "test/util/capability_util.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 FixtureTruncateTest : public FileTest {
void SetUp() override { FileTest::SetUp(); }
};
TEST_F(FixtureTruncateTest, Truncate) {
// 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());
});
// Check that it starts at size zero.
struct stat buf;
ASSERT_THAT(fstat(test_file_fd_.get(), &buf), SyscallSucceeds());
EXPECT_EQ(buf.st_size, 0);
// Stay at size zero.
EXPECT_THAT(truncate(test_file_name_.c_str(), 0), SyscallSucceeds());
ASSERT_THAT(fstat(test_file_fd_.get(), &buf), SyscallSucceeds());
EXPECT_EQ(buf.st_size, 0);
// Grow to ten bytes.
EXPECT_THAT(truncate(test_file_name_.c_str(), 10), SyscallSucceeds());
ASSERT_THAT(fstat(test_file_fd_.get(), &buf), SyscallSucceeds());
EXPECT_EQ(buf.st_size, 10);
// Can't be truncated to a negative number.
EXPECT_THAT(truncate(test_file_name_.c_str(), -1),
SyscallFailsWithErrno(EINVAL));
// Try growing past the file size limit.
sigset_t new_mask;
sigemptyset(&new_mask);
sigaddset(&new_mask, SIGXFSZ);
sigprocmask(SIG_BLOCK, &new_mask, nullptr);
struct timespec timelimit;
timelimit.tv_sec = 10;
timelimit.tv_nsec = 0;
struct rlimit setlim;
setlim.rlim_cur = 1024;
setlim.rlim_max = RLIM_INFINITY;
ASSERT_THAT(setrlimit(RLIMIT_FSIZE, &setlim), SyscallSucceeds());
EXPECT_THAT(truncate(test_file_name_.c_str(), 1025),
SyscallFailsWithErrno(EFBIG));
EXPECT_EQ(sigtimedwait(&new_mask, nullptr, &timelimit), SIGXFSZ);
ASSERT_THAT(sigprocmask(SIG_UNBLOCK, &new_mask, nullptr), SyscallSucceeds());
// Shrink back down to zero.
EXPECT_THAT(truncate(test_file_name_.c_str(), 0), SyscallSucceeds());
ASSERT_THAT(fstat(test_file_fd_.get(), &buf), SyscallSucceeds());
EXPECT_EQ(buf.st_size, 0);
}
TEST_F(FixtureTruncateTest, Ftruncate) {
// 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());
});
// Check that it starts at size zero.
struct stat buf;
ASSERT_THAT(fstat(test_file_fd_.get(), &buf), SyscallSucceeds());
EXPECT_EQ(buf.st_size, 0);
// Stay at size zero.
EXPECT_THAT(ftruncate(test_file_fd_.get(), 0), SyscallSucceeds());
ASSERT_THAT(fstat(test_file_fd_.get(), &buf), SyscallSucceeds());
EXPECT_EQ(buf.st_size, 0);
// Grow to ten bytes.
EXPECT_THAT(ftruncate(test_file_fd_.get(), 10), SyscallSucceeds());
ASSERT_THAT(fstat(test_file_fd_.get(), &buf), SyscallSucceeds());
EXPECT_EQ(buf.st_size, 10);
// Can't be truncated to a negative number.
EXPECT_THAT(ftruncate(test_file_fd_.get(), -1),
SyscallFailsWithErrno(EINVAL));
// Try growing past the file size limit.
sigset_t new_mask;
sigemptyset(&new_mask);
sigaddset(&new_mask, SIGXFSZ);
sigprocmask(SIG_BLOCK, &new_mask, nullptr);
struct timespec timelimit;
timelimit.tv_sec = 10;
timelimit.tv_nsec = 0;
struct rlimit setlim;
setlim.rlim_cur = 1024;
setlim.rlim_max = RLIM_INFINITY;
ASSERT_THAT(setrlimit(RLIMIT_FSIZE, &setlim), SyscallSucceeds());
EXPECT_THAT(ftruncate(test_file_fd_.get(), 1025),
SyscallFailsWithErrno(EFBIG));
EXPECT_EQ(sigtimedwait(&new_mask, nullptr, &timelimit), SIGXFSZ);
ASSERT_THAT(sigprocmask(SIG_UNBLOCK, &new_mask, nullptr), SyscallSucceeds());
// Shrink back down to zero.
EXPECT_THAT(ftruncate(test_file_fd_.get(), 0), SyscallSucceeds());
ASSERT_THAT(fstat(test_file_fd_.get(), &buf), SyscallSucceeds());
EXPECT_EQ(buf.st_size, 0);
}
// Truncating a file down clears that portion of the file.
TEST_F(FixtureTruncateTest, FtruncateShrinkGrow) {
std::vector<char> buf(10, 'a');
EXPECT_THAT(WriteFd(test_file_fd_.get(), buf.data(), buf.size()),
SyscallSucceedsWithValue(buf.size()));
// Shrink then regrow the file. This should clear the second half of the file.
EXPECT_THAT(ftruncate(test_file_fd_.get(), 5), SyscallSucceeds());
EXPECT_THAT(ftruncate(test_file_fd_.get(), 10), SyscallSucceeds());
EXPECT_THAT(lseek(test_file_fd_.get(), 0, SEEK_SET), SyscallSucceeds());
std::vector<char> buf2(10);
EXPECT_THAT(ReadFd(test_file_fd_.get(), buf2.data(), buf2.size()),
SyscallSucceedsWithValue(buf2.size()));
std::vector<char> expect = {'a', 'a', 'a', 'a', 'a',
'\0', '\0', '\0', '\0', '\0'};
EXPECT_EQ(expect, buf2);
}
TEST(TruncateTest, TruncateDir) {
auto temp_dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
EXPECT_THAT(truncate(temp_dir.path().c_str(), 0),
SyscallFailsWithErrno(EISDIR));
}
TEST(TruncateTest, FtruncateDir) {
auto temp_dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
const FileDescriptor fd =
ASSERT_NO_ERRNO_AND_VALUE(Open(temp_dir.path(), O_DIRECTORY | O_RDONLY));
EXPECT_THAT(ftruncate(fd.get(), 0), SyscallFailsWithErrno(EINVAL));
}
TEST(TruncateTest, TruncateNonWriteable) {
// Make sure we don't have CAP_DAC_OVERRIDE, since that allows the user to
// always override write permissions.
ASSERT_NO_ERRNO(SetCapability(CAP_DAC_OVERRIDE, false));
auto temp_file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
GetAbsoluteTestTmpdir(), absl::string_view(), 0555 /* mode */));
EXPECT_THAT(truncate(temp_file.path().c_str(), 0),
SyscallFailsWithErrno(EACCES));
}
TEST(TruncateTest, FtruncateNonWriteable) {
auto temp_file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileWith(
GetAbsoluteTestTmpdir(), absl::string_view(), 0555 /* mode */));
const FileDescriptor fd =
ASSERT_NO_ERRNO_AND_VALUE(Open(temp_file.path(), O_RDONLY));
EXPECT_THAT(ftruncate(fd.get(), 0), SyscallFailsWithErrno(EINVAL));
}
TEST(TruncateTest, TruncateNonExist) {
EXPECT_THAT(truncate("/foo/bar", 0), SyscallFailsWithErrno(ENOENT));
}
TEST(TruncateTest, FtruncateVirtualTmp_NoRandomSave) {
auto temp_file = NewTempAbsPathInDir("/dev/shm");
const DisableSave ds; // Incompatible permissions.
const FileDescriptor fd =
ASSERT_NO_ERRNO_AND_VALUE(Open(temp_file, O_RDWR | O_CREAT | O_EXCL, 0));
EXPECT_THAT(ftruncate(fd.get(), 100), SyscallSucceeds());
}
// NOTE: There are additional truncate(2)/ftruncate(2) tests in mknod.cc
// which are there to avoid running the tests on a number of different
// filesystems which may not support mknod.
} // namespace
} // namespace testing
} // namespace gvisor
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