Sampling PKCS5_PBKDF2_HMAC_SHA1 for adaptive cycles

sample.c

#include <stdio.h>
#include <stdbool.h>
#include <pthread.h>
#include <semaphore.h>
#include <signal.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <openssl/hmac.h>

static sem_t * semAlaram;
typedef void (*sighandler_t)(int);
static sighandler_t handler = NULL;
static int runCount = 0;
static int secondsToRun = 1;
static int cycleCount = 0;
int runResults = 0;
int numberOfRuns = 5;

static void* waitForAlaram(void* arg)
{
  while(true){
    sem_wait(semAlaram);
    runResults += cycleCount;
    printf("Run %d complete - cycle count:%d\n", runCount, cycleCount);
    cycleCount = 0;
  }
  return NULL;
}

static void sighandler(int signal){

  if(signal == SIGALRM){
    runCount++;
    sem_post(semAlaram);
    alarm(secondsToRun);
  }else if (handler){
    handler(signal);
  }
}

void calculateCycles(){
  
  char *password = "5^ra6fU&jHWXad";
  char *salt = "123456789";
  int iterationCount = 1;
  int keySize = 256;
  unsigned char buffer[1024];

    PKCS5_PBKDF2_HMAC_SHA1(password, strlen(password), (unsigned char *)salt, strlen(salt),
                           iterationCount, keySize, buffer);
    cycleCount++;
}

int main(int argc, char *argv[]){

  pthread_t thread;
  if(argc == 2){
    numberOfRuns = atoi(argv[1]);
  }
  
  semAlaram = sem_open("semaphore", O_CREAT, S_IRUSR | S_IWUSR, 0);
  if(semAlaram == SEM_FAILED){
    printf("error initializing semaphore: %s", strerror(errno));
    return -1;
  }

  if(pthread_create(&thread, NULL, waitForAlaram, NULL) != 0){
    printf("error creating thread: %s", strerror(errno));
    return -1;
  }

  handler = signal(SIGALRM, sighandler);
  alarm(secondsToRun);

  while(runCount < numberOfRuns){
    calculateCycles();
  }

  printf("Sampling done - average cycle count:%d\n", runResults/numberOfRuns);
  return 0;
}