src/debugging/bsd_like.ipp

// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// 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 <__config>

#if defined(__FreeBSD__) // Include order matters.
#  include <libutil.h>
#  include <sys/param.h>
#  include <sys/proc.h>
#  include <sys/user.h>
#endif // defined(__FreeBSD__)
#include <array>
#include <debugging>
#include <sys/sysctl.h>
#include <sys/types.h>
#include <unistd.h>

_LIBCPP_BEGIN_NAMESPACE_STD

_LIBCPP_BEGIN_EXPLICIT_ABI_ANNOTATIONS

[[gnu::weak]] bool is_debugger_present() noexcept {
  // Technical Q&A QA1361: Detecting the Debugger
  // https://developer.apple.com/library/archive/qa/qa1361/_index.html

  // Initialize mib, which tells 'sysctl' to fetch the information about the current process.

  array<int, 4> __mib{CTL_KERN, KERN_PROC, KERN_PROC_PID, ::getpid()};

  // Initialize the flags so that, if 'sysctl' fails for some bizarre
  // reason, we get a predictable result.

  ::kinfo_proc __info{};

  // Call sysctl.
  // https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man3/sysctl.3.html

  size_t __info_size = sizeof(__info);
  if (::sysctl(__mib.data(), __mib.size(), &__info, &__info_size, nullptr, 0) != 0) {
    _LIBCPP_ASSERT_INTERNAL(false, "'sysctl' runtime error");
    return false;
  }

  // The process is being debugged if the 'P_TRACED' flag is set.
  // https://github.com/freebsd/freebsd-src/blob/7f3184ba797452703904d33377dada5f0f8eae96/sys/sys/proc.h#L822

#if defined(__FreeBSD__)
  const auto __p_flag = __info.ki_flag;
#else // __APPLE__
  const auto __p_flag = __info.kp_proc.p_flag;
#endif

  return ((__p_flag & P_TRACED) != 0);
}

_LIBCPP_END_EXPLICIT_ABI_ANNOTATIONS

_LIBCPP_END_NAMESPACE_STD