[libc-commits] [libc] [libc] add ioctl (PR #141393)

[Joseph Huber via libc-commits]

================
@@ -0,0 +1,37 @@
+//===---------- Linux implementation of the ioctl 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/ioctl/ioctl.h"
+
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "src/__support/common.h"
+#include "src/errno/libc_errno.h"
+#include <stdarg.h>
+#include <sys/syscall.h> // For syscall numbers.
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, ioctl, (int fd, unsigned long request, ...)) {
+  va_list vargs;
+  va_start(vargs, request);
+  void *data_pointer = va_arg(vargs, void *);
+  int ret =
+      LIBC_NAMESPACE::syscall_impl<int>(SYS_ioctl, fd, request, data_pointer);
+  va_end(vargs);
+
+  // Some ioctls can be expected to return positive values
+  if (ret >= 0) {
+    return ret;
+  }
----------------
jhuber6 wrote:

```suggestion
  if (ret >= 0)
    return ret;
```

https://github.com/llvm/llvm-project/pull/141393