1 files changed, 218 insertions, 0 deletions
diff --git a/test/syscalls/linux/truncate.cc b/test/syscalls/linux/truncate.cc
new file mode 100644
index 000000000..c988c6380
--- /dev/null
+++ b/test/syscalls/linux/truncate.cc
@@ -0,0 +1,218 @@
+// 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