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

[Joseph Huber via libc-commits]

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@@ -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 *);
----------------
jhuber6 wrote:

>From the man pages,
> The arg argument represents additional information that is needed by this specific STREAMS device to perform the requested function. The type of arg depends upon the particular control request, but it shall be either an integer or a pointer to a device-specific data structure.

Do we need to handle  that somehow? I guess it depends if it's a `uintptr_t` or an actual int.

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