Open source system call tests.

PiperOrigin-RevId: 224886231
Change-Id: I0fccb4d994601739d8b16b1d4e6b31f40297fb22

1 files changed, 117 insertions, 0 deletions

diff --git a/test/syscalls/linux/read.cc b/test/syscalls/linux/read.cc
new file mode 100644
index 000000000..eb1b5bc10
--- /dev/null
+++ b/test/syscalls/linux/read.cc
@@ -0,0 +1,117 @@
+// 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 <fcntl.h>
+#include <unistd.h>
+#include <vector>
+
+#include "gtest/gtest.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));
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor