[libc] [llvm] [libc][c11] Add stdio.h's rename() function (PR #85068)

[Nick Desaulniers via llvm-commits]

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@@ -0,0 +1,37 @@
+//===-- Linux implementation of rename ------------------------------------===//
+//
+// 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/stdio/rename.h"
+
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "src/__support/common.h"
+
+#include "src/errno/libc_errno.h"
+#include <fcntl.h>       // For AT_* macros.
+#include <sys/syscall.h> // For syscall numbers.
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(int, rename, (const char *oldpath, const char *newpath)) {
+#if defined(SYS_rename)
+  int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_rename, oldpath, newpath);
+#elif defined(SYS_renameat)
+  int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_renameat, AT_FDCWD, oldpath,
+                                              AT_FDCWD, newpath);
+#else
+  int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_renameat2, AT_FDCWD, oldpath,
+                                              AT_FDCWD, newpath, 0);
+#endif
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nickdesaulniers wrote:

I don't think any of this is necessary. Remove?

https://github.com/llvm/llvm-project/pull/85068