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/macros/config.h" 14 #include "src/errno/libc_errno.h" 15 #include <sys/syscall.h> // For syscall numbers. 16 17 namespace LIBC_NAMESPACE_DECL { 18 19 LLVM_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