Getting your own process without using procfs on Linux

demo.sh

#!/bin/sh

gcc test.c
./a.out
# /home/josteink/demo/a.out
cp a.out b.out
./b.out
# /home/josteink/demo/b.out
ln -s a.out c.out
./c.out
# /home/josteink/demo/a.out

test.c

// Shamelessly copied from Stack Overflow
// http://stackoverflow.com/a/23621200
//
// In the lack of a SYSCTL enum for process self-identification,
// the following seems to work:

#include <stdlib.h>
#include <stdio.h>
#include <sys/auxv.h>
#include <linux/limits.h>

int main(int argc, char **argv)
{
  char* relative = (char*)getauxval(AT_EXECFN);

  char absolute[PATH_MAX];
  char *res = realpath(relative, absolute);
  if (res) {
    printf("%s\n", absolute);
  }
  else {
    printf("Unable to resolve self!\n");
  }
  return(0);
}