/* Copyright (C) 2011 DJ Delorie, see COPYING.DJ for details */
/* Copyright (C) 2002 DJ Delorie, see COPYING.DJ for details */
/* Copyright (C) 2001 DJ Delorie, see COPYING.DJ for details */
/* Copyright (C) 1996 DJ Delorie, see COPYING.DJ for details */
/* Copyright (C) 1995 DJ Delorie, see COPYING.DJ for details */
#include <libc/stubs.h>
#include <stdarg.h>
#include <fcntl.h>
#include <errno.h>
#include <go32.h>
#include <dpmi.h>
#include <io.h>
#include <dos.h>
#include <unistd.h>
#include <libc/dosio.h>
#include <sys/fsext.h>
#include <libc/fsexthlp.h>

int
_creat(const char* filename, int attrib)
{
  __dpmi_regs r = {0};
  int rv;
  unsigned use_lfn = _USE_LFN;

  if (filename == 0)
  {
    errno = EINVAL;
    return -1;
  }

  if (__FSEXT_call_open_handlers_wrapper(__FSEXT_creat, &rv, filename, attrib))
    return rv;

  if (use_lfn)
  {
    r.x.flags = 1;		/* Always set CF before calling a 0x71NN function. */
    r.x.ax = 0x716c;
    r.x.bx = 0x0002;		/* Open r/w. */
    /* The FAT32 bit should _not_ be set on Windows 2000, because
       that bit fails function 716Ch on W2K.  The test below is
       based on the assumption that W2K returns DOS version 5.  */
    if (7 <= _osmajor && _osmajor < 10)
    {
      r.x.bx |= 0x1000; /* 0x1000 is FAT32 extended size. */
    }
    r.x.dx = 0x0012;		/* Create, truncate if exists */
    r.x.si = __tb_offset;
  }
  else
  {
    if (7 <= _osmajor && _osmajor < 10)
    {
      r.x.ax = 0x6c00;
      r.x.bx = 0x1002;           /* Open r/w with FAT32 extended size. */
      /* FAT32 extended size flag doesn't help on WINDOZE 4.1 (98). It
	 seems it has a bug which only lets you create these big files
	 if LFN is enabled. */
      r.x.dx = 0x0012;           /* Create, truncate if exists */
      r.x.si = __tb_offset;
    }
    else
    {
      r.h.ah = 0x3c;
      r.x.dx = __tb_offset;
    }
  }
do_create:
  r.x.cx = attrib;
  r.x.ds = __tb_segment;
  _put_path(filename);
  __dpmi_int(0x21, &r);

  if (r.x.ax == 0x7100)
  {
    /*  Never assume that the complete LFN API is implemented,
        so check that AX != 0x7100.  E.G.: MSDOS 6.22 and DOSLFN 0.40.
        If not supported fall back on SFN API 0x3C.  */
    use_lfn = 0;
    r.h.ah = 0x3c;
    r.x.dx = __tb_offset;
    goto do_create;
  }
  else if (r.x.flags & 1)
  {
    errno = __doserr_to_errno(r.x.ax);
    return -1;
  }
  if (use_lfn && _os_trueversion == 0x532)
  {
    /* Windows 2000 or XP; or NT with LFN TSR.  Windows 2000 behaves
       badly when using IOCTL and write-truncate calls on LFN handles.
       We close the long name file and re-open it with _open.c (short)
       to work around the bugs. */
    rv = _open(filename, 2);	/* 2 is a read/write flag */
    if (rv != -1)
    {
      dup2(rv, r.x.ax);	/* Re-open failure, continue with LFN handle */
      _close(rv);	/* Replace ax, put handle in first position (bugs) */
    }
  }
  __file_handle_set(r.x.ax, O_BINARY);
  return r.x.ax;
}