[libc-commits] [libc] [libc] pipe(2) linux syscall wrapper and unittest (PR #85514)

[Nick Desaulniers via libc-commits]

================
@@ -0,0 +1,63 @@
+//===-- Unittests for pipe2
+//-------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/errno/libc_errno.h"
+#include "src/unistd/close.h"
+#include "src/unistd/pipe2.h"
+#include "src/unistd/read.h"
+#include "src/unistd/write.h"
+#include "test/UnitTest/ErrnoSetterMatcher.h"
+#include "test/UnitTest/Test.h"
+
+#include <fcntl.h>
+
+TEST(LlvmLibcPipe2Test, ReadAndWriteViaPipe2) {
+  int pipefd[2];
+  int flags;
+
+  LIBC_NAMESPACE::libc_errno = 0;
+  using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
+
+  // Create pipe(2) with flags set to 0
+  flags = 0;
+  ASSERT_NE(LIBC_NAMESPACE::pipe2(pipefd, flags), -1);
+  ASSERT_ERRNO_SUCCESS();
+
+  // Write something via the pipe and read from other end
+  constexpr char MESSAGE[] = "Hello from the write end!";
+  constexpr size_t MESSAGE_SIZE = sizeof(MESSAGE);
+  char buf[MESSAGE_SIZE];
+  ASSERT_EQ(ssize_t(MESSAGE_SIZE),
+            LIBC_NAMESPACE::write(pipefd[1], MESSAGE, MESSAGE_SIZE));
+  ASSERT_EQ(ssize_t(MESSAGE_SIZE),
+            LIBC_NAMESPACE::read(pipefd[0], buf, MESSAGE_SIZE));
+  ASSERT_STREQ(buf, MESSAGE);
+
+  // Close the pipe file descriptors
+  ASSERT_NE(LIBC_NAMESPACE::close(pipefd[0]), -1);
+  ASSERT_ERRNO_SUCCESS();
+  ASSERT_NE(LIBC_NAMESPACE::close(pipefd[1]), -1);
+  ASSERT_ERRNO_SUCCESS();
+}
+
+TEST(LlvmLibcPipe2Test, Pipe2InvalidFlags) {
+  int invalidflags = O_CREAT | O_PATH | O_SYNC;
+  int pipefd[2];
+
+  using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
+  ASSERT_THAT(LIBC_NAMESPACE::pipe2(pipefd, invalidflags), Fails(EINVAL));
----------------
nickdesaulniers wrote:

Note that this is currently failing in presubmit.

```
/var/lib/buildkite-agent/builds/linux-56-59b8f5d88-6mhbj-1/llvm-project/github-pull-requests/libc/test/src/unistd/pipe2_test.cpp:54: FAILURE
Failed to match LIBC_NAMESPACE::pipe2(pipefd, invalidflags) against Fails(EINVAL).
Expected return value to be equal to -1 but got -22.
```

https://github.com/llvm/llvm-project/pull/85514