libc/winsup/cygwin/fhandler_floppy.cc

/* fhandler_floppy.cc.  See fhandler.h for a description of the
   fhandler classes.

   Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
   2009, 2011 Red Hat, Inc.

This file is part of Cygwin.

This software is a copyrighted work licensed under the terms of the
Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
details. */

#include "winsup.h"
#include <alloca.h>
#include <unistd.h>
#include <winioctl.h>
#include <cygwin/rdevio.h>
#include <cygwin/hdreg.h>
#include <cygwin/fs.h>
#include "cygerrno.h"
#include "security.h"
#include "path.h"
#include "fhandler.h"
#include "ntdll.h"

#define IS_EOM(err)	((err) == ERROR_INVALID_PARAMETER \
			 || (err) == ERROR_SEEK \
			 || (err) == ERROR_SECTOR_NOT_FOUND)

/**********************************************************************/
/* fhandler_dev_floppy */

fhandler_dev_floppy::fhandler_dev_floppy ()
  : fhandler_dev_raw (), status ()
{
}

int
fhandler_dev_floppy::get_drive_info (struct hd_geometry *geo)
{
  char dbuf[256];
  char pbuf[256];

  DISK_GEOMETRY *di = NULL;
  PARTITION_INFORMATION_EX *pix = NULL;
  PARTITION_INFORMATION *pi = NULL;
  DWORD bytes_read = 0;

  /* Always try using the new EX ioctls first (>= XP).  If not available,
     fall back to trying the old non-EX ioctls.
     Unfortunately the EX ioctls are not implemented in the floppy driver. */
  if (wincap.has_disk_ex_ioctls () && get_major () != DEV_FLOPPY_MAJOR)
    {
      if (!DeviceIoControl (get_handle (),
			    IOCTL_DISK_GET_DRIVE_GEOMETRY_EX, NULL, 0,
			    dbuf, 256, &bytes_read, NULL))
	__seterrno ();
      else
	{
	  di = &((DISK_GEOMETRY_EX *) dbuf)->Geometry;
	  if (!DeviceIoControl (get_handle (),
				IOCTL_DISK_GET_PARTITION_INFO_EX, NULL, 0,
				pbuf, 256, &bytes_read, NULL))
	    __seterrno ();
	  else
	    pix = (PARTITION_INFORMATION_EX *) pbuf;
	}
    }
  if (!di)
    {
      if (!DeviceIoControl (get_handle (),
			    IOCTL_DISK_GET_DRIVE_GEOMETRY, NULL, 0,
			    dbuf, 256, &bytes_read, NULL))
	__seterrno ();
      else
	{
	  di = (DISK_GEOMETRY *) dbuf;
	  if (!DeviceIoControl (get_handle (),
				IOCTL_DISK_GET_PARTITION_INFO, NULL, 0,
				pbuf, 256, &bytes_read, NULL))
	    __seterrno ();
	  else
	    pi = (PARTITION_INFORMATION *) pbuf;
	}
    }
  if (!di)
    {
      /* Up to Win2K, even IOCTL_DISK_GET_DRIVE_GEOMETRY fails when trying
	 it on CD or DVD drives.  In that case fall back to requesting
	 simple file system information. */
      NTSTATUS status;
      IO_STATUS_BLOCK io;
      FILE_FS_SIZE_INFORMATION ffsi;

      status = NtQueryVolumeInformationFile (get_handle (), &io, &ffsi,
					     sizeof ffsi,
					     FileFsSizeInformation);
      if (!NT_SUCCESS (status))
	{
	  __seterrno_from_nt_status (status);
	  return -1;
	}
      debug_printf ("fsys geometry: (%D units)*(%u sec)*(%u bps)",
		    ffsi.TotalAllocationUnits.QuadPart,
		    ffsi.SectorsPerAllocationUnit,
		    ffsi.BytesPerSector);
      bytes_per_sector = ffsi.BytesPerSector;
      drive_size = ffsi.TotalAllocationUnits.QuadPart
		   * ffsi.SectorsPerAllocationUnit
		   * ffsi.BytesPerSector;
      if (geo)
	{
	  geo->heads = 1;
	  geo->sectors = ffsi.SectorsPerAllocationUnit;
	  geo->cylinders = ffsi.TotalAllocationUnits.LowPart;
	  geo->start = 0;
	}
    }
  else
    {
      debug_printf ("disk geometry: (%D cyl)*(%u trk)*(%u sec)*(%u bps)",
		     di->Cylinders.QuadPart,
		     di->TracksPerCylinder,
		     di->SectorsPerTrack,
		     di->BytesPerSector);
      bytes_per_sector = di->BytesPerSector;
      if (pix)
	{
	  debug_printf ("partition info: offset %D  length %D",
			pix->StartingOffset.QuadPart,
			pix->PartitionLength.QuadPart);
	  drive_size = pix->PartitionLength.QuadPart;
	}
      else if (pi)
	{
	  debug_printf ("partition info: offset %D  length %D",
			pi->StartingOffset.QuadPart,
			pi->PartitionLength.QuadPart);
	  drive_size = pi->PartitionLength.QuadPart;
	}
      else
	{
	  /* Getting the partition size by using the drive geometry information
	     looks wrong, but this is a historical necessity.  NT4 didn't
	     maintain partition information for the whole drive (aka
	     "partition 0"), but returned ERROR_INVALID_HANDLE instead.  That
	     got fixed in W2K. */
	  drive_size = di->Cylinders.QuadPart * di->TracksPerCylinder
		       * di->SectorsPerTrack * di->BytesPerSector;
	}
      if (geo)
	{
	  geo->heads = di->TracksPerCylinder;
	  geo->sectors = di->SectorsPerTrack;
	  geo->cylinders = di->Cylinders.LowPart;
	  if (pix)
	    geo->start = pix->StartingOffset.QuadPart >> 9ULL;
	  else if (pi)
	    geo->start = pi->StartingOffset.QuadPart >> 9ULL;
	  else
	    geo->start = 0;
	}
    }
  debug_printf ("drive size: %D", drive_size);

  return 0;
}

/* Wrapper functions for ReadFile and WriteFile to simplify error handling. */
BOOL
fhandler_dev_floppy::read_file (void *buf, DWORD to_read, DWORD *read, int *err)
{
  BOOL ret;

  *err = 0;
  if (!(ret = ReadFile (get_handle (), buf, to_read, read, 0)))
    *err = GetLastError ();
  syscall_printf ("%d (err %d) = ReadFile (%d, %d, to_read %d, read %d, 0)",
		  ret, *err, get_handle (), buf, to_read, *read);
  return ret;
}

/* See comment in write_file below. */
BOOL
fhandler_dev_floppy::lock_partition (DWORD to_write)
{
  DWORD bytes_read;

  /* The simple case.  We have only a single partition open anyway. 
     Try to lock the partition so that a subsequent write succeeds.
     If there's some file handle open on one of the affected partitions,
     this fails, but that's how it works on Vista and later... */
  if (get_minor () % 16 != 0)
    {
      if (!DeviceIoControl (get_handle (), FSCTL_LOCK_VOLUME,
			   NULL, 0, NULL, 0, &bytes_read, NULL))
	{
	  debug_printf ("DeviceIoControl (FSCTL_LOCK_VOLUME) failed, %E");
	  return FALSE;
	}
      return TRUE;
    }

  /* The tricky case.  We're writing to the entire disk.  What this code
     basically does is to find out if the current write operation affects
     one or more partitions on the disk.  If so, it tries to lock all these
     partitions and stores the handles for a subsequent close(). */
  NTSTATUS status;
  IO_STATUS_BLOCK io;
  FILE_POSITION_INFORMATION fpi;
  /* Allocate space for 4 times the maximum partition count we can handle.
     The reason is that for *every* single logical drive in an extended
     partition on an MBR drive, 3 filler entries with partition number set
     to 0 are added into the partition table returned by
     IOCTL_DISK_GET_DRIVE_LAYOUT_EX.  The first of them reproduces the data
     of the next partition entry, if any, except for the partiton number.
     Then two entries with everything set to 0 follow.  Well, the
     documentation states that for MBR drives the number of partition entries
     in the PARTITION_INFORMATION_EX array is always a multiple of 4, but,
     nevertheless, how crappy is that layout? */
  const DWORD size = sizeof (DRIVE_LAYOUT_INFORMATION_EX)
		     + 4 * MAX_PARTITIONS * sizeof (PARTITION_INFORMATION_EX);
  PDRIVE_LAYOUT_INFORMATION_EX pdlix = (PDRIVE_LAYOUT_INFORMATION_EX)
				       alloca (size);
  BOOL found = FALSE;
  
  /* Fetch current file pointer position on disk. */
  status = NtQueryInformationFile (get_handle (), &io, &fpi, sizeof fpi,
				   FilePositionInformation);
  if (!NT_SUCCESS (status))
    {
      debug_printf ("NtQueryInformationFile(FilePositionInformation): %p",
		    status);
      return FALSE;
    }
  /* Fetch drive layout to get start and end positions of partitions on disk. */
  if (!DeviceIoControl (get_handle (), IOCTL_DISK_GET_DRIVE_LAYOUT_EX, NULL, 0,
  			pdlix, size, &bytes_read, NULL))
    {
      debug_printf ("DeviceIoControl(IOCTL_DISK_GET_DRIVE_LAYOUT_EX): %E");
      return FALSE;
    }
  /* Scan through partition info to find the partition(s) into which we're
     currently trying to write. */
  PARTITION_INFORMATION_EX *ppie = pdlix->PartitionEntry;
  for (DWORD i = 0; i < pdlix->PartitionCount; ++i, ++ppie)
    {
      /* A partition number of 0 denotes an extended partition or one of the
	 aforementioned filler entries.  Just skip. */
      if (ppie->PartitionNumber == 0)
      	continue;
      /* Check if our writing range affects this partition. */
      if (fpi.CurrentByteOffset.QuadPart   < ppie->StartingOffset.QuadPart
					     + ppie->PartitionLength.QuadPart
	  && ppie->StartingOffset.QuadPart < fpi.CurrentByteOffset.QuadPart
					     + to_write)
	{
	  /* Yes.  Now check if we can handle it.  We can only handle
	     up to MAX_PARTITIONS partitions.  The partition numbering is
	     one-based, so we decrement the partition number by 1 when using
	     as index into the partition array. */
	  DWORD &part_no = ppie->PartitionNumber;
	  if (part_no >= MAX_PARTITIONS)
	    return FALSE;
	  found = TRUE;
	  debug_printf ("%d %D->%D : %D->%D", part_no,
			ppie->StartingOffset.QuadPart,
			ppie->StartingOffset.QuadPart
			+ ppie->PartitionLength.QuadPart,
			fpi.CurrentByteOffset.QuadPart,
			fpi.CurrentByteOffset.QuadPart + to_write);
	  /* Do we already have partitions?  If not, create it. */
	  if (!partitions)
	    {
	      partitions = (part_t *) ccalloc_abort (HEAP_FHANDLER, 1,
						     sizeof (part_t));
	      partitions->refcnt = 1;
	    }
	  /* Next, check if the partition is already open.  If so, skip it. */
	  if (partitions->hdl[part_no - 1])
	    continue;
	  /* Now open the partition and lock it. */
	  WCHAR part[MAX_PATH], *p;
	  NTSTATUS status;
	  UNICODE_STRING upart;
	  OBJECT_ATTRIBUTES attr;
	  IO_STATUS_BLOCK io;

	  sys_mbstowcs (part, MAX_PATH, get_win32_name ());
	  p = wcschr (part, L'\0') - 1;
	  __small_swprintf (p, L"%d", part_no);
	  RtlInitUnicodeString (&upart, part);
	  InitializeObjectAttributes (&attr, &upart,
				      OBJ_CASE_INSENSITIVE
				      | ((get_flags () & O_CLOEXEC)
					 ? 0 : OBJ_INHERIT),
				      NULL, NULL);
	  status = NtOpenFile (&partitions->hdl[part_no - 1],
			       GENERIC_READ | GENERIC_WRITE, &attr,
			       &io, FILE_SHARE_READ | FILE_SHARE_WRITE, 0);
	  if (!NT_SUCCESS (status))
	    {
	      debug_printf ("NtCreateFile(%W): %p", part, status);
	      return FALSE;
	    }
	  if (!DeviceIoControl (partitions->hdl[part_no - 1], FSCTL_LOCK_VOLUME,
				NULL, 0, NULL, 0, &bytes_read, NULL))
	    {
	      debug_printf ("DeviceIoControl (%W, FSCTL_LOCK_VOLUME) "
			    "failed, %E", part);
	      return FALSE;
	    }
	}
    }
  /* If we didn't find a single matching partition, the "Access denied"
     had another reason, so return FALSE in that case. */
  return found;
}

BOOL
fhandler_dev_floppy::write_file (const void *buf, DWORD to_write,
				 DWORD *written, int *err)
{
  BOOL ret;

  *err = 0;
  if (!(ret = WriteFile (get_handle (), buf, to_write, written, 0)))
    *err = GetLastError ();
  /* When writing to a disk or partition on Vista, an "Access denied" error
     is potentially a result of the raw disk write restriction.  See
     http://support.microsoft.com/kb/942448 for details.  What we have to
     do here is to lock the partition and retry.  The previous solution
     locked one or all partitions immediately in open.  Which is overly
     wasteful, given that the user might only want to change, say, the boot
     sector. */
  if (*err == ERROR_ACCESS_DENIED
      && wincap.has_restricted_raw_disk_access ()
      && get_major () != DEV_FLOPPY_MAJOR
      && get_major () != DEV_CDROM_MAJOR
      && (get_flags () & O_ACCMODE) != O_RDONLY
      && lock_partition (to_write))
    {
      *err = 0;
      if (!(ret = WriteFile (get_handle (), buf, to_write, written, 0)))
	*err = GetLastError ();
    }
  syscall_printf ("%d (err %d) = WriteFile (%d, %d, write %d, written %d, 0)",
		  ret, *err, get_handle (), buf, to_write, *written);
  return ret;
}

int
fhandler_dev_floppy::open (int flags, mode_t)
{
  /* The correct size of the buffer would be 512 bytes, which is the atomic
     size, supported by WinNT.  Unfortunately, the performance is worse than
     access to file system on same device!  Setting buffer size to a
     relatively big value increases performance by means.  The new ioctl call
     with 'rdevio.h' header file supports changing this value.

     As default buffer size, we're using some value which is a multiple of
     the typical tar and cpio buffer sizes, Except O_DIRECT is set, in which
     case we're not buffering at all. */
  devbufsiz = (flags & O_DIRECT) ? 0L : 61440L;
  int ret = fhandler_dev_raw::open (flags);

  if (ret)
    {
      DWORD bytes_read;

      if (get_drive_info (NULL))
	{
	  close ();
	  return 0;
	}
      /* If we're trying to access a CD/DVD drive, or an entire disk,
         make sure we're actually allowed to read *all* of the device.
	 This is actually documented in the MSDN CreateFile man page. */
      if (get_major () != DEV_FLOPPY_MAJOR
	  && (get_major () == DEV_CDROM_MAJOR || get_minor () % 16 == 0)
	  && !DeviceIoControl (get_handle (), FSCTL_ALLOW_EXTENDED_DASD_IO,
			       NULL, 0, NULL, 0, &bytes_read, NULL))
	debug_printf ("DeviceIoControl (FSCTL_ALLOW_EXTENDED_DASD_IO) "
		      "failed, %E");
    }

  return ret;
}

int
fhandler_dev_floppy::close ()
{
  int ret = fhandler_dev_raw::close ();

  if (partitions && InterlockedDecrement (&partitions->refcnt) == 0)
    {
      for (int i = 0; i < MAX_PARTITIONS; ++i)
	if (partitions->hdl[i])
	  NtClose (partitions->hdl[i]);
      cfree (partitions);
    }
  return ret;
}

int
fhandler_dev_floppy::dup (fhandler_base *child)
{
  fhandler_dev_floppy *fhc = (fhandler_dev_floppy *) child;

  int ret = fhandler_dev_raw::dup (child);

  if (!ret)
    {
      fhc->drive_size = drive_size;
      fhc->bytes_per_sector = bytes_per_sector;
      if (partitions)
	{
	  InterlockedIncrement (&partitions->refcnt);
	  fhc->partitions = partitions;
	}
      fhc->eom_detected (eom_detected ());
    }
  return ret;
}

inline _off64_t
fhandler_dev_floppy::get_current_position ()
{
  LARGE_INTEGER off = { QuadPart: 0LL };
  off.LowPart = SetFilePointer (get_handle (), 0, &off.HighPart, FILE_CURRENT);
  return off.QuadPart;
}

void __stdcall
fhandler_dev_floppy::raw_read (void *ptr, size_t& ulen)
{
  DWORD bytes_read = 0;
  DWORD read2;
  DWORD bytes_to_read;
  int ret;
  size_t len = ulen;
  char *tgt;
  char *p = (char *) ptr;

  /* Checking a previous end of media */
  if (eom_detected () && !lastblk_to_read ())
    {
      set_errno (ENOSPC);
      goto err;
    }

  if (devbuf)
    {
      while (len > 0)
	{
	  if (devbufstart < devbufend)
	    {
	      bytes_to_read = min (len, devbufend - devbufstart);
	      debug_printf ("read %d bytes from buffer (rest %d)",
			    bytes_to_read,
			    devbufend - devbufstart - bytes_to_read);
	      memcpy (p, devbuf + devbufstart, bytes_to_read);
	      len -= bytes_to_read;
	      p += bytes_to_read;
	      bytes_read += bytes_to_read;
	      devbufstart += bytes_to_read;

	      if (lastblk_to_read ())
		{
		  lastblk_to_read (false);
		  break;
		}
	    }
	  if (len > 0)
	    {
	      if (len >= devbufsiz)
		{
		  bytes_to_read = (len / bytes_per_sector) * bytes_per_sector;
		  tgt = p;
		}
	      else
		{
		  tgt = devbuf;
		  bytes_to_read = devbufsiz;
		}
	      _off64_t current_position = get_current_position ();
	      if (current_position + bytes_to_read >= drive_size)
		bytes_to_read = drive_size - current_position;
	      if (!bytes_to_read)
		break;

	      debug_printf ("read %d bytes from pos %U %s", bytes_to_read,
			    current_position,
			    len < devbufsiz ? "into buffer" : "directly");
	      if (!read_file (tgt, bytes_to_read, &read2, &ret))
		{
		  if (!IS_EOM (ret))
		    {
		      __seterrno ();
		      goto err;
		    }

		  eom_detected (true);

		  if (!read2)
		    {
		      if (!bytes_read)
			{
			  debug_printf ("return -1, set errno to ENOSPC");
			  set_errno (ENOSPC);
			  goto err;
			}
		      break;
		    }
		  lastblk_to_read (true);
		}
	      if (!read2)
	       break;
	      if (tgt == devbuf)
		{
		  devbufstart = 0;
		  devbufend = read2;
		}
	      else
		{
		  len -= read2;
		  p += read2;
		  bytes_read += read2;
		}
	    }
	}
    }
  else
    {
      _off64_t current_position = get_current_position ();
      bytes_to_read = len;
      if (current_position + bytes_to_read >= drive_size)
	bytes_to_read = drive_size - current_position;
      debug_printf ("read %d bytes from pos %U directly", bytes_to_read,
		    current_position);
      if (bytes_to_read && !read_file (p, bytes_to_read, &bytes_read, &ret))
	{
	  if (!IS_EOM (ret))
	    {
	      __seterrno ();
	      goto err;
	    }
	  if (bytes_read)
	    eom_detected (true);
	  else
	    {
	      debug_printf ("return -1, set errno to ENOSPC");
	      set_errno (ENOSPC);
	      goto err;
	    }
	}
    }

  ulen = (size_t) bytes_read;
  return;

err:
  ulen = (size_t) -1;
}

int __stdcall
fhandler_dev_floppy::raw_write (const void *ptr, size_t len)
{
  DWORD bytes_written = 0;
  char *p = (char *) ptr;
  int ret;

  /* Checking a previous end of media on tape */
  if (eom_detected ())
    {
      set_errno (ENOSPC);
      return -1;
    }

  /* Invalidate buffer. */
  devbufstart = devbufend = 0;

  if (len > 0)
    {
      if (!write_file (p, len, &bytes_written, &ret))
	{
	  if (!IS_EOM (ret))
	    {
	      __seterrno ();
	      return -1;
	    }
	  eom_detected (true);
	  if (!bytes_written)
	    {
	      set_errno (ENOSPC);
	      return -1;
	    }
	}
    }
  return bytes_written;
}

_off64_t
fhandler_dev_floppy::lseek (_off64_t offset, int whence)
{
  char buf[bytes_per_sector];
  _off64_t lloffset = offset;
  _off64_t current_pos = (_off64_t) -1;
  LARGE_INTEGER sector_aligned_offset;
  size_t bytes_left;

  if (whence == SEEK_END)
    {
      lloffset += drive_size;
      whence = SEEK_SET;
    }
  else if (whence == SEEK_CUR)
    {
      current_pos = get_current_position ();
      lloffset += current_pos - (devbufend - devbufstart);
      whence = SEEK_SET;
    }

  if (whence != SEEK_SET || lloffset < 0 || lloffset > drive_size)
    {
      set_errno (EINVAL);
      return -1;
    }

  /* If new position is in buffered range, adjust buffer and return */
  if (devbufstart < devbufend)
    {
      if (current_pos == (_off64_t) -1)
	current_pos = get_current_position ();
      if (current_pos - devbufend <= lloffset && lloffset <= current_pos)
	{
	  devbufstart = devbufend - (current_pos - lloffset);
	  return lloffset;
	}
    }

  sector_aligned_offset.QuadPart = (lloffset / bytes_per_sector)
				   * bytes_per_sector;
  bytes_left = lloffset - sector_aligned_offset.QuadPart;

  /* Invalidate buffer. */
  devbufstart = devbufend = 0;

  sector_aligned_offset.LowPart =
			SetFilePointer (get_handle (),
					sector_aligned_offset.LowPart,
					&sector_aligned_offset.HighPart,
					FILE_BEGIN);
  if (sector_aligned_offset.LowPart == INVALID_SET_FILE_POINTER
      && GetLastError ())
    {
      __seterrno ();
      return -1;
    }

  eom_detected (false);

  if (bytes_left)
    {
      raw_read (buf, bytes_left);
      if (bytes_left == (size_t) -1)
	return -1;
    }

  return sector_aligned_offset.QuadPart + bytes_left;
}

int
fhandler_dev_floppy::ioctl (unsigned int cmd, void *buf)
{
  DISK_GEOMETRY di;
  DWORD bytes_read;
  switch (cmd)
    {
    case HDIO_GETGEO:
      {
	debug_printf ("HDIO_GETGEO");
	return get_drive_info ((struct hd_geometry *) buf);
      }
    case BLKGETSIZE:
    case BLKGETSIZE64:
      {
	debug_printf ("BLKGETSIZE");
	if (cmd == BLKGETSIZE)
	  *(long *)buf = drive_size >> 9UL;
	else
	  *(_off64_t *)buf = drive_size;
	return 0;
      }
    case BLKRRPART:
      {
	debug_printf ("BLKRRPART");
	if (!DeviceIoControl (get_handle (),
			      IOCTL_DISK_UPDATE_DRIVE_SIZE,
			      NULL, 0,
			      &di, sizeof (di),
			      &bytes_read, NULL))
	  {
	    __seterrno ();
	    return -1;
	  }
	get_drive_info (NULL);
	return 0;
      }
    case BLKSSZGET:
      {
	debug_printf ("BLKSSZGET");
	*(int *)buf = bytes_per_sector;
	return 0;
      }
    case RDSETBLK:
      /* Just check the restriction that blocksize must be a multiple
	 of the sector size of the underlying volume sector size,
	 then fall through to fhandler_dev_raw::ioctl. */
      if (((struct rdop *) buf)->rd_parm % bytes_per_sector)
	{
	  SetLastError (ERROR_INVALID_PARAMETER);
	  __seterrno ();
	  return -1;
	}
      /*FALLTHRU*/
    default:
      return fhandler_dev_raw::ioctl (cmd, buf);
    }
}