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 16 namespace LIBC_NAMESPACE { 17 18 LLVM_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, option, arg2, arg3, arg4, 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