1//===---------- Linux implementation of the prctl function ----------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "src/sys/prctl/prctl.h"
10
11#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
12
13#include "src/__support/libc_errno.h"
14#include "src/__support/macros/config.h"
15#include <sys/syscall.h> // For syscall numbers.
16
17namespace LIBC_NAMESPACE_DECL {
18
19LLVM_LIBC_FUNCTION(int, prctl,
20 (int option, unsigned long arg2, unsigned long arg3,
21 unsigned long arg4, unsigned long arg5)) {
22 long ret =
23 LIBC_NAMESPACE::syscall_impl(SYS_prctl, option, arg2, arg3, arg4, arg5);
24 // The manpage states that "... return the nonnegative values described
25 // above. All other option values return 0 on success. On error,
26 // -1 is returned, and errno is set to indicate the error."
27 // According to the kernel implementation
28 // (https://github.com/torvalds/linux/blob/bee0e7762ad2c6025b9f5245c040fcc36ef2bde8/kernel/sys.c#L2442),
29 // return value from the syscall is set to 0 on default so we do not need to
30 // set the value on success manually.
31 if (ret < 0) {
32 libc_errno = static_cast<int>(-ret);
33 return -1;
34 }
35 return static_cast<int>(ret);
36}
37
38} // namespace LIBC_NAMESPACE_DECL
39

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source code of libc/src/sys/prctl/linux/prctl.cpp