Detecting an attached gdb on Mac OS X

detect_gdb.c

#include <sys/sysctl.h>
#include <unistd.h>

#include <err.h>
#include <errno.h>
#include <stdio.h>

int main()
{
  int mib[4];
  size_t bufSize = 0;
  int localError = 0;
  struct kinfo_proc kinfoProc;
  
  mib[0] = CTL_KERN;
  mib[1] = KERN_PROC;
  mib[2] = KERN_PROC_PID;
  mib[3] = getpid();

  bufSize = sizeof(kinfoProc);
  localError = sysctl(mib, 4, &kinfoProc, &bufSize, NULL, 0);
  
  if(localError < 0)
  {
    perror("Failure calling sysctl");
    return 0;
  }
  
  if(kinfoProc.kp_proc.p_flag & P_TRACED)
    printf("I am traced\n");
  
  else
    printf("I am not traced\n");
  
  return 0;
}