Open source system call tests.

PiperOrigin-RevId: 224886231
Change-Id: I0fccb4d994601739d8b16b1d4e6b31f40297fb22

1 files changed, 130 insertions, 0 deletions

diff --git a/test/syscalls/linux/open_create.cc b/test/syscalls/linux/open_create.cc
new file mode 100644
index 000000000..b2cbd63d1
--- /dev/null
+++ b/test/syscalls/linux/open_create.cc
@@ -0,0 +1,130 @@
+// Copyright 2018 Google LLC
+//
+// 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 <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "gtest/gtest.h"
+#include "test/syscalls/linux/temp_umask.h"
+#include "test/util/capability_util.h"
+#include "test/util/file_descriptor.h"
+#include "test/util/fs_util.h"
+#include "test/util/temp_path.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+TEST(CreateTest, TmpFile) {
+  int fd;
+  EXPECT_THAT(fd = open(JoinPath(GetAbsoluteTestTmpdir(), "a").c_str(),
+                        O_RDWR | O_CREAT, 0666),
+              SyscallSucceeds());
+  EXPECT_THAT(close(fd), SyscallSucceeds());
+}
+
+TEST(CreateTest, ExistingFile) {
+  int fd;
+  EXPECT_THAT(
+      fd = open(JoinPath(GetAbsoluteTestTmpdir(), "ExistingFile").c_str(),
+                O_RDWR | O_CREAT, 0666),
+      SyscallSucceeds());
+  EXPECT_THAT(close(fd), SyscallSucceeds());
+
+  EXPECT_THAT(
+      fd = open(JoinPath(GetAbsoluteTestTmpdir(), "ExistingFile").c_str(),
+                O_RDWR | O_CREAT, 0666),
+      SyscallSucceeds());
+  EXPECT_THAT(close(fd), SyscallSucceeds());
+}
+
+TEST(CreateTest, CreateAtFile) {
+  int dirfd;
+  EXPECT_THAT(dirfd = open(GetAbsoluteTestTmpdir().c_str(), O_DIRECTORY, 0666),
+              SyscallSucceeds());
+  EXPECT_THAT(openat(dirfd, "CreateAtFile", O_RDWR | O_CREAT, 0666),
+              SyscallSucceeds());
+  EXPECT_THAT(close(dirfd), SyscallSucceeds());
+}
+
+TEST(CreateTest, HonorsUmask_NoRandomSave) {
+  const DisableSave ds;  // file cannot be re-opened as writable.
+  TempUmask mask(0222);
+  int fd;
+  ASSERT_THAT(
+      fd = open(JoinPath(GetAbsoluteTestTmpdir(), "UmaskedFile").c_str(),
+                O_RDWR | O_CREAT, 0666),
+      SyscallSucceeds());
+  struct stat statbuf;
+  ASSERT_THAT(fstat(fd, &statbuf), SyscallSucceeds());
+  EXPECT_EQ(0444, statbuf.st_mode & 0777);
+  EXPECT_THAT(close(fd), SyscallSucceeds());
+}
+
+TEST(CreateTest, CreateExclusively) {
+  std::string filename = NewTempAbsPath();
+
+  int fd;
+  ASSERT_THAT(fd = open(filename.c_str(), O_CREAT | O_RDWR, 0644),
+              SyscallSucceeds());
+  EXPECT_THAT(close(fd), SyscallSucceeds());
+
+  EXPECT_THAT(open(filename.c_str(), O_CREAT | O_EXCL | O_RDWR, 0644),
+              SyscallFailsWithErrno(EEXIST));
+}
+
+TEST(CreateTest, CreateFailsOnUnpermittedDir) {
+  // Make sure we don't have CAP_DAC_OVERRIDE, since that allows the user to
+  // always override directory permissions.
+  ASSERT_NO_ERRNO(SetCapability(CAP_DAC_OVERRIDE, false));
+  ASSERT_THAT(open("/foo", O_CREAT | O_RDWR, 0644),
+              SyscallFailsWithErrno(EACCES));
+}
+
+TEST(CreateTest, CreateFailsOnDirWithoutWritePerms) {
+  // Make sure we don't have CAP_DAC_OVERRIDE, since that allows the user to
+  // always override directory permissions.
+  ASSERT_NO_ERRNO(SetCapability(CAP_DAC_OVERRIDE, false));
+  auto parent = ASSERT_NO_ERRNO_AND_VALUE(
+      TempPath::CreateDirWith(GetAbsoluteTestTmpdir(), 0555));
+  auto file = JoinPath(parent.path(), "foo");
+  ASSERT_THAT(open(file.c_str(), O_CREAT | O_RDWR, 0644),
+              SyscallFailsWithErrno(EACCES));
+}
+
+// A file originally created RW, but opened RO can later be opened RW.
+TEST(CreateTest, OpenCreateROThenRW) {
+  TempPath file(NewTempAbsPath());
+
+  // Create a RW file, but only open it RO.
+  FileDescriptor fd1 = ASSERT_NO_ERRNO_AND_VALUE(
+      Open(file.path(), O_CREAT | O_EXCL | O_RDONLY, 0644));
+
+  // Now get a RW FD.
+  FileDescriptor fd2 = ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR));
+
+  // fd1 is not writable, but fd2 is.
+  char c = 'a';
+  EXPECT_THAT(WriteFd(fd1.get(), &c, 1), SyscallFailsWithErrno(EBADF));
+  EXPECT_THAT(WriteFd(fd2.get(), &c, 1), SyscallSucceedsWithValue(1));
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor