#define _GNU_SOURCE
#include <dlfcn.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>

typedef long (*orig_sysconf_f_type)(int name);

long sysconf(int name) {
  orig_sysconf_f_type orig;
  orig = (orig_sysconf_f_type)dlsym(RTLD_NEXT, "sysconf");

  if (name != _SC_NPROCESSORS_CONF && name != _SC_NPROCESSORS_ONLN) {
    return orig(name);
  }

  printf("Overriding call sysconf %d\n", name);

  long numcpus = 0;
  char *env = getenv("NUMCPUS");
  printf("Env NUMCPUS %s\n", env);
  if (env != NULL && strlen(env) > 0) {
    numcpus = strtol(env, NULL, 10);
  }
  if (numcpus == 0) {
    numcpus = orig(name);
  }
  printf("Return %ld\n", numcpus);
  fflush(stdout);
  return numcpus;
}