#include <stdio.h>
#include <sys/mman.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <inttypes.h>
#include <stdbool.h>
#include "i.h"

typedef int64_t INTN;
typedef int64_t INT64;
typedef int32_t INT32;
typedef uint64_t UINTN;
typedef uint64_t UINT64;
typedef uint32_t UINT32;
typedef uint16_t UINT16;
typedef uint8_t UINT8;
typedef void VOID;
typedef bool BOOLEAN;
typedef char CHAR8;

#define IN
#define OUT
#define STATIC static
#define CONST const 
#define MEMORY_SIZE (1 * 1024 * 1024)

STATIC
VOID *
MapMemory (
  IN INTN    Fd,
  IN UINT64  Length,
  IN INTN    Prot,
  IN INTN    Flags
  )
{
  VOID *Base = (VOID *) 0x40000000UL;

  Base = mmap ((void *) Base, Length, Prot, Flags, Fd, 0);
  return Base;
}

int
ReadFile (
  IN  CHAR8 *FileName,
  IN  VOID  *Buffer
  )
{
  int   Fd;
  VOID  *Res;
  UINTN FileSize;

  Fd = open (FileName, O_RDWR);
  if (Fd < 0) {
    fprintf(stderr, "Couldn't open '%s': %s\n",
            FileName, strerror (errno));
    return -1;
  }

  FileSize = lseek (Fd, 0, SEEK_END);
  if (FileSize == (UINTN) -1) {
    fprintf(stderr, "Couldn't size '%s': %s\n",
            FileName, strerror (errno));
    return -1;
  }

  lseek (Fd, 0, SEEK_SET);
  
  if (read(Fd, Buffer, FileSize) != FileSize) {
    fprintf(stderr, "Couldn't read '%s': %s\n",
            FileName, strerror (errno));
    return -1;
  }

  close (Fd);

  return 0;
}

int
main (
  IN  int   Argc,
  IN  char  **Argv
  )
{
  VOID *MemoryBase;
  char *FdName;
  int Status;
  fns f;
  void (*entry)(fns *fns);

  f.puts = puts;
  f.sjmp = setjmp;
  f.ljmp = longjmp;
  
  MemoryBase =  MapMemory (0, MEMORY_SIZE,
                           PROT_READ  | PROT_WRITE |  PROT_EXEC,
                           MAP_PRIVATE | MAP_ANONYMOUS
                           );
  if (MemoryBase ==  MAP_FAILED) {
    fprintf(stderr, "Couldn't allocate memoru\n");
    return -1;
  }

  if (Argc > 1) {
    FdName = Argv[1];
  } else {
    FdName = "k.bin";
  }
  Status = ReadFile (FdName, MemoryBase);
  if (Status != 0) {
    return -1;
  }

  /*
   *
   * This is important on real E2K Linux. longjmp2 will fail if the
   * source and dest VM regions have non-matching attributes.
   *
   * Real system: prot must be PROT_EXEC | PROT_READ, or longjmp2
   * will kill the task.
   *
   * Qemu: works fine with PROT_READ | PROT_WRITE | PROT_EXEC.
   */
  mprotect (MemoryBase, MEMORY_SIZE, PROT_EXEC | PROT_READ);
  entry = MemoryBase;

  printf("Calling %p\n", entry);
  entry (&f);
  printf("Back from %p\n", entry);

  return 0;
}