#include "test_fault_helper.h"
#include "fail.h"
#include <sys/mman.h>
#include <stdlib.h>
#include <unistd.h>
#include <assert.h>
#include <TargetConditionals.h>

#define MEMSIZE (1L<<30)

static char* memblock;

int test_fault_setup() {
    char *ptr;
    int pgsz = getpagesize();
    int retval;

    memblock = (char *)mmap(NULL, MEMSIZE, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0);
    VERIFY(memblock != MAP_FAILED, "mmap failed");

    /* make sure memory is paged */
    for(ptr = memblock; ptr<memblock+MEMSIZE; ptr+= pgsz) {
        *ptr = 1;
    }

    /* set to read only, then back to read write so it faults on first write */
    retval = mprotect(memblock, MEMSIZE, PROT_READ);
    VERIFY(retval == 0, "mprotect failed");

    retval = mprotect(memblock, MEMSIZE, PROT_READ | PROT_WRITE);
    VERIFY(retval == 0, "mprotect failed");

    return PERFINDEX_SUCCESS;
}

int test_fault_helper(int thread_id, int num_threads, long long length, testtype_t testtype) {
    char *ptr;
    int pgsz = getpagesize();
    int retval;

    long long num_pages = MEMSIZE / pgsz;
    long long region_len = num_pages/num_threads;
    long long region_start = region_len * thread_id; 
    long long region_end;

    if(thread_id < num_pages % num_threads) {
        region_start += thread_id;
        region_len++;
    }
    else {
        region_start += num_pages % num_threads;
    }

    region_start *= pgsz;
    region_len *= pgsz;
    region_end = region_start + region_len;

    long long left = length;

    while(1) {
        for(ptr = memblock+region_start; ptr<memblock+region_end; ptr+= pgsz) {
            *ptr = 1;
            left--;
            if(left==0)
                break;
        }

        if(left==0)
            break;

        if(testtype == TESTFAULT) {
            retval = mprotect(memblock+region_start, region_len, PROT_READ) == 0;
            VERIFY(retval == 0, "mprotect failed");
            retval = mprotect(memblock+region_start, region_len, PROT_READ | PROT_WRITE) == 0;
            VERIFY(retval == 0, "mprotect failed");
        }

        else if(testtype == TESTZFOD) {
            retval = munmap(memblock+region_start, region_len) == 0;
            VERIFY(retval == 0, "munmap failed");
            ptr = mmap(memblock+region_start, region_len, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE | MAP_FIXED, -1, 0);
            VERIFY(ptr != 0, "mmap failed");
        }
    }
    return PERFINDEX_SUCCESS;
}