lockmem.c: grabs and locks a specified amount of memory

lockmem.c

/**
 * lockmem.c: grabs and locks a specified amount of memory
 *
 * Written by Arto Bendiken <http://ar.to/>
 * Compile using "gcc -o lockmem lockmem.c"
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>

void lockmem_abort(char* err) {
  perror(err);
  exit(1);
}

void* lockmem_alloc(size_t bytes) {
  void* memory = malloc(bytes);
  if (memory == NULL) {
    lockmem_abort("malloc");
  }
  return memory;
}

void lockmem_lock(void* memory, size_t bytes) {
  if (mlock(memory, bytes)) {
    lockmem_abort("mlock");
  }
}

int main(int argc, char** argv) {
  if (argc < 2) {
    printf("Usage: lockmem BYTES\n");
    exit(-1);
  }
  else {
    size_t bytes = atoi(argv[1]);

    if (strchr(argv[1], 'k') || strchr(argv[1], 'K')) {
      bytes *= 1024;
    }
    if (strchr(argv[1], 'm') || strchr(argv[1], 'M')) {
      bytes *= 1024 * 1024;
    }
    if (strchr(argv[1], 'g') || strchr(argv[1], 'G')) {
      bytes *= 1024 * 1024 * 1024;
    }

    printf("Grabbing & locking %zd bytes of memory...", bytes);

    void* memory = lockmem_alloc(bytes);
    lockmem_lock(memory, bytes);
    printf("done.\nPress any key to release memory and terminate...");

    getchar(); // wait for keypress
  }

  return 0;
}