module os

#include <sys/ptrace.h>

fn C.ptrace(i32, u32, voidptr, i32) i32

// debugger_present returns a bool indicating if the process is being debugged.
pub fn debugger_present() bool {
    $if openbsd {
        // check if a child process could trace its parent process,
        // if not a debugger must be present
        pid := fork()
        if pid == 0 {
            ppid := getppid()
            /*
             * On OpenBSD, impossible to trace a parent process from its child.
             * Possible errors:
             *   - EBUSY: process already traced
             *   - EPERM: process is not a child of tracer (sysctl kern.global_ptrace=0)
             *   - EINVAL: process is an ancestor of the current process and not init
             *     (sysctl kern.global_ptrace=1)
             */
            if C.ptrace(C.PT_ATTACH, ppid, unsafe { nil }, 0) < 0 {
                if C.errno == C.EBUSY {
                    // external debugger must be present
                    exit(1)
                } else {
                    // no external debugger
                    exit(0)
                }
            }
        } else {
            mut status := 0
            // wait until the child process dies
            C.waitpid(pid, &status, 0)
            // check the exit code of the child process check
            if posix_wait_status_exit_code(status) == 0 {
                return false
            } else {
                return true
            }
        }
    }
    return false
}