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/errno/libc_errno.h"
14#include <sys/syscall.h> // For syscall numbers.
15
16namespace LIBC_NAMESPACE {
17
18LLVM_LIBC_FUNCTION(int, prctl,
19 (int option, unsigned long arg2, unsigned long arg3,
20 unsigned long arg4, unsigned long arg5)) {
21 long ret =
22 LIBC_NAMESPACE::syscall_impl(SYS_prctl, arg1: option, arg2: arg2, arg3: arg3, arg4: arg4, arg5: arg5);
23 // The manpage states that "... return the nonnegative values described
24 // above. All other option values return 0 on success. On error,
25 // -1 is returned, and errno is set to indicate the error."
26 // According to the kernel implementation
27 // (https://github.com/torvalds/linux/blob/bee0e7762ad2c6025b9f5245c040fcc36ef2bde8/kernel/sys.c#L2442),
28 // return value from the syscall is set to 0 on default so we do not need to
29 // set the value on success manually.
30 if (ret < 0) {
31 libc_errno = static_cast<int>(-ret);
32 return -1;
33 }
34 return static_cast<int>(ret);
35}
36
37} // namespace LIBC_NAMESPACE
38

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