#include <stdio.h>
#include <signal.h>
#include <string.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <libmcpu.h>

#define CHECK(c,m) do{if(!(c)){fprintf(stderr,"FAIL: %s\n",m);return 1;}}while(0)

static int
page_aligned( const void *p, size_t page )
{
  return( p != 0 && ( (size_t)p % page ) == 0 );
}

int
main( void )
{
  long ps;
  size_t page;
  pid_t pid;
  int status;
  __mpu_UNIT_t code[3] =
  {
    0x00, 0x00, 0x00
  };

  __cpu_init();
  ps = sysconf( _SC_PAGESIZE );
  CHECK( ps > 0, "host page size" );
  page = (size_t)ps;

  CHECK( CPU_ABI_MAX_ALIGN == 16U, "ABI maximum natural alignment" );
  CHECK( CPU_ABI_STACK_ALIGN == 16U, "ABI stack alignment" );
  CHECK( CPU_ABI_ARGUMENT_BLOCK_ALIGN == 16U, "ABI argument block alignment" );
  CHECK( CPU_DATA_NULL_GUARD_SIZE == 16U, "DATA NULL guard size" );
  CHECK( CPU_NULL_PTR == __mpu_UINT64_C( 0 ), "NULL PTR64 encoding" );

  CHECK( __cpu_data_alloc( 1 ) == 0, "allocate one-byte DATA" );
  CHECK( __cpu_data_size() == 1, "DATA architectural size is exact" );
  CHECK( page_aligned( __cpu_data_ptr(), page ), "DATA host base is page aligned" );
  CHECK( __cpu_data_ptr()[0] == 0, "anonymous DATA mapping is zero-filled" );
  __cpu_data_ptr()[0] = 0x5a;
  CHECK( __cpu_data_ptr()[0] == 0x5a, "DATA mapping is writable" );

  CHECK( __cpu_stack_alloc( 1 ) == 0, "allocate one-byte STACK" );
  CHECK( __cpu_stack_size() == 1, "STACK architectural size is exact" );
  CHECK( page_aligned( __cpu_stack_ptr(), page ), "STACK host base is page aligned" );
  CHECK( __cpu_stack_ptr()[0] == 0, "anonymous STACK mapping is zero-filled" );
  CHECK( __cpu_sp == 1 && __cpu_fp == 1, "empty STACK uses exact architectural size" );

  CHECK( __cpu_program_alloc( sizeof( code ) ) == 0, "allocate PROGRAM for loading" );
  CHECK( __cpu_program_size() == sizeof( code ), "PROGRAM architectural size is exact" );
  CHECK( page_aligned( __cpu_program_ptr(), page ), "PROGRAM host base is page aligned" );
  memcpy( __cpu_program_ptr(), code, sizeof( code ) );
  __cpu_program_ptr()[0] = 0x12;
  /* PROGRAM is writable during image loading. */
  CHECK( __cpu_program_ptr()[0] == 0x12, "PROGRAM writable before protect" );
  CHECK( __cpu_program_protect() == 0, "protect PROGRAM read-only" );

  /* Verify host protection without crashing the test process itself. */
  pid = fork();
  CHECK( pid >= 0, "fork for PROGRAM protection test" );
  if( pid == 0 )
  {
    volatile __mpu_UNIT_t *p = __cpu_program_ptr();
    p[0] = 0x34;
    _exit( 0 );
  }
  CHECK( waitpid( pid, &status, 0 ) == pid, "wait for protection child" );
  CHECK( WIFSIGNALED( status ), "PROGRAM host write is trapped" );
  CHECK( WTERMSIG( status ) == SIGSEGV || WTERMSIG( status ) == SIGBUS,
        "PROGRAM write fault signal");

  /* Reallocation must unmap the protected image and create a fresh RW mapping. */
  CHECK( __cpu_program_alloc( 2 ) == 0, "reallocate PROGRAM after protection" );
  CHECK( __cpu_program_size() == 2, "reallocated PROGRAM exact size" );
  __cpu_program_ptr()[0] = 0x56;
  CHECK( __cpu_program_ptr()[0] == 0x56, "new PROGRAM mapping writable for loading" );

  __cpu_free_context();
  puts( "libcpu anonymous-mmap memory regression: PASS" );
  return( 0 );
}