[libc-commits] [libc] Add Linux sys call wrapper in LibC [ Issue #110122 ] (PR #110307)

[Michael Jones via libc-commits]

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@@ -0,0 +1,44 @@
+//===----- Linux implementation of the POSIX remap_file_pages function ----===//
+//
+// 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/sys/mman/remap_file_pages.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 {
+
+// This function is currently linux only. It has to be refactored suitably if
+// remap_file_pages is to be supported on non-linux operating systems also.
+LLVM_LIBC_FUNCTION(int, remap_file_pages,
+                   (void *addr, size_t size, int prot, size_t pgoff, int flags))
+                    {
+#ifdef SYS_remap_file_pages
+  long syscall_number = SYS_remap_file_pages;
+#else
+#error "remap_file_pages syscall is not available."
+#endif
+
+
+  int ret = LIBC_NAMESPACE::syscall_impl<int>(
+  syscall_number, reinterpret_cast<long>(addr), size, prot, pgoff, flags);
+
+  // A negative return value indicates an error with the magnitude of the
+  // value being the error code.
+  if (ret < 0) {
+    libc_errno = ret;
+    return -1;
+  }
+
+  return 0;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
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michaelrj-google wrote:

nit: needs ending newline

https://github.com/llvm/llvm-project/pull/110307