[libc-commits] [libc] [libc] [unistd] implement pipe2 syscall wrapper (PR #114474)

[Michael Jones via libc-commits]

================
@@ -0,0 +1,30 @@
+//===-- Linux implementation of pipe --------------------------------------===//
+//
+// 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/unistd/pipe2.h"
+
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+#include "src/errno/libc_errno.h"
+#include <sys/syscall.h> // For syscall numbers.
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, pipe2, (int pipefd[2], int flags)) {
+  int ret = LIBC_NAMESPACE::syscall_impl<int>(
+      SYS_pipe2, reinterpret_cast<long>(pipefd), flags);
+
----------------
michaelrj-google wrote:

You need to unpoison the memory here for the sanitizers to work properly. They can't tell that the kernel initialized the memory without being explicitly told.
```suggestion
  MSAN_UNPOISON(pipefd, sizeof(int) * 2);
```

https://github.com/llvm/llvm-project/pull/114474