fhandler_tape.cc

cygwin, 著名的在win32下模拟unix操作系统的东东

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

   Copyright 1999, 2000, 2001, 2002 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 <sys/termios.h>
#include <errno.h>
#include <unistd.h>
#include <sys/mtio.h>
#include "cygerrno.h"
#include "perprocess.h"
#include "security.h"
#include "fhandler.h"
#include "path.h"
#include "dtable.h"
#include "cygheap.h"

/**********************************************************************/
/* fhandler_dev_tape */

void
fhandler_dev_tape::clear (void)
{
  lasterr = 0;
  fhandler_dev_raw::clear ();
}

int
fhandler_dev_tape::is_eom (int win_error)
{
  int ret = ((win_error == ERROR_END_OF_MEDIA)
	  || (win_error == ERROR_EOM_OVERFLOW)
	  || (win_error == ERROR_NO_DATA_DETECTED));
  if (ret)
    debug_printf ("end of medium");
  return ret;
}

int
fhandler_dev_tape::is_eof (int win_error)
{
  int ret = ((win_error == ERROR_FILEMARK_DETECTED)
	  || (win_error == ERROR_SETMARK_DETECTED));
  if (ret)
    debug_printf ("end of file");
  return ret;
}

fhandler_dev_tape::fhandler_dev_tape (int unit)
  : fhandler_dev_raw (FH_TAPE, unit)
{
  debug_printf ("unit: %d", unit);
}

int
fhandler_dev_tape::open (path_conv *real_path, int flags, mode_t)
{
  int ret;

  devbufsiz = 1L;

  ret = fhandler_dev_raw::open (real_path, flags);
  if (ret)
    {
      struct mtget get;
      struct mtop op;
      struct mtpos pos;

      if (!ioctl (MTIOCGET, &get))
	/* Tape drive supports and is set to variable block size. */
	if (get.mt_dsreg == 0)
	  devbufsiz = get.mt_maxblksize;
	else
	  devbufsiz = get.mt_dsreg;
	varblkop = get.mt_dsreg == 0;

      if (devbufsiz > 1L)
	devbuf = new char [devbufsiz];

      /* The following rewind in position 0 solves a problem which appears
       * in case of multi volume archives: The last ReadFile on first medium
       * returns ERROR_NO_DATA_DETECTED. After media change, all subsequent
       * ReadFile calls return ERROR_NO_DATA_DETECTED, too.
       * The call to tape_set_pos seems to reset some internal flags. */
      if ((! ioctl (MTIOCPOS, &pos)) && (! pos.mt_blkno))
	{
	  op.mt_op = MTREW;
	  ioctl (MTIOCTOP, &op);
	}

      if (flags & O_APPEND)
	{
	  /* In append mode, seek to beginning of next filemark */
	  op.mt_op = MTFSFM;
	  op.mt_count = 1;
	  ioctl (MTIOCTOP, &op);
	}
    }

  return ret;
}

int
fhandler_dev_tape::close (void)
{
  struct mtop op;
  int ret = 0;

  if (is_writing)
    {
      ret = writebuf ();
      if ((has_written) && (! eom_detected))
	{
	  /* if last operation was writing, write a filemark */
	  debug_printf ("writing filemark");
	  op.mt_op = MTWEOF;
	  op.mt_count = 1;
	  ioctl (MTIOCTOP, &op);
	}
    }

  // To protected reads on signaling (e.g. Ctrl-C)
  eof_detected = 1;

  if (is_rewind_device ())
    {
      debug_printf ("rewinding");
      op.mt_op = MTREW;
      ioctl (MTIOCTOP, &op);
    }

  if (ret)
    {
      fhandler_dev_raw::close ();
      return ret;
    }

  return fhandler_dev_raw::close ();
}

int
fhandler_dev_tape::fstat (struct __stat64 *buf, path_conv *pc)
{
  int ret;

  if (!(ret = fhandler_base::fstat (buf, pc)))
    {
      struct mtget get;

      if (!ioctl (MTIOCGET, &get))
	buf->st_blocks = get.mt_capacity / buf->st_blksize;
    }

  return ret;
}

__off64_t
fhandler_dev_tape::lseek (__off64_t offset, int whence)
{
  struct mtop op;
  struct mtpos pos;

  debug_printf ("lseek (%s, %d, %d)", get_name (), offset, whence);

  writebuf ();
  eom_detected = eof_detected = 0;
  lastblk_to_read = 0;
  devbufstart = devbufend = 0;

  if (ioctl (MTIOCPOS, &pos))
    {
      return ILLEGAL_SEEK;
    }

  switch (whence)
    {
      case SEEK_END:
	op.mt_op = MTFSF;
	op.mt_count = 1;
	if (ioctl (MTIOCTOP, &op))
	  return -1;
	break;
      case SEEK_SET:
	if (whence == SEEK_SET && offset < 0)
	  {
	    set_errno (EINVAL);
	    return -1;
	  }
	break;
      case SEEK_CUR:
	break;
      default:
	set_errno (EINVAL);
	return -1;
    }

  op.mt_op = MTFSR;
  op.mt_count = offset / devbufsiz
		- (whence == SEEK_SET ? pos.mt_blkno : 0);

  if (op.mt_count < 0)
    {
      op.mt_op = MTBSR;
      op.mt_count = -op.mt_count;
    }

  if (ioctl (MTIOCTOP, &op) || ioctl (MTIOCPOS, &pos))
    return -1;

  return (pos.mt_blkno * devbufsiz);
}

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

  fhc->lasterr = lasterr;
  return fhandler_dev_raw::dup (child);
}

int
fhandler_dev_tape::ioctl (unsigned int cmd, void *buf)
{
  int ret = NO_ERROR;
  unsigned long block;

  if (cmd == MTIOCTOP)
    {
      struct mtop *op = (struct mtop *) buf;

      if (! op)
	ret = ERROR_INVALID_PARAMETER;
      else
	switch (op->mt_op)
	  {
	  case MTRESET:
	    break;
	  case MTFSF:
	    ret = tape_set_pos (TAPE_SPACE_FILEMARKS, op->mt_count);
	    break;
	  case MTBSF:
	    ret = tape_set_pos (TAPE_SPACE_FILEMARKS, -op->mt_count);
	    break;
	  case MTFSR:
	    ret = tape_set_pos (TAPE_SPACE_RELATIVE_BLOCKS, op->mt_count);
	    break;
	  case MTBSR:
	    ret = tape_set_pos (TAPE_SPACE_RELATIVE_BLOCKS, -op->mt_count);
	    break;
	  case MTWEOF:
	    if (tape_get_feature (TAPE_DRIVE_WRITE_FILEMARKS))
	      ret = tape_write_marks (TAPE_FILEMARKS, op->mt_count);
	    else if (tape_get_feature (TAPE_DRIVE_WRITE_LONG_FMKS))
	      ret = tape_write_marks (TAPE_LONG_FILEMARKS, op->mt_count);
	    else
	      ret = tape_write_marks (TAPE_SHORT_FILEMARKS, op->mt_count);
	    break;
	  case MTREW:
	    ret = tape_set_pos (TAPE_REWIND, 0);
	    break;
	  case MTOFFL:
	    ret = tape_prepare (TAPE_UNLOAD);
	    break;
	  case MTNOP:
	    break;
	  case MTRETEN:
	    if (! tape_get_feature (TAPE_DRIVE_END_OF_DATA))
	      ret = ERROR_INVALID_PARAMETER;
	    else if (! (ret = tape_set_pos (TAPE_REWIND, 0, FALSE)))
	      ret = tape_prepare (TAPE_TENSION);
	    break;
	  case MTBSFM:
	    ret = tape_set_pos (TAPE_SPACE_FILEMARKS, -op->mt_count, TRUE);
	    break;
	  case MTFSFM:
	    ret = tape_set_pos (TAPE_SPACE_FILEMARKS, op->mt_count, TRUE);
	    break;
	  case MTEOM:
	    if (tape_get_feature (TAPE_DRIVE_END_OF_DATA))
	      ret = tape_set_pos (TAPE_SPACE_END_OF_DATA, 0);
	    else
	      ret = tape_set_pos (TAPE_SPACE_FILEMARKS, 32767);
	    break;
	  case MTERASE:
	    ret = tape_erase (TAPE_ERASE_SHORT);
	    break;
	  case MTRAS1:
	  case MTRAS2:
	  case MTRAS3:
	    ret = ERROR_INVALID_PARAMETER;
	    break;
	  case MTSETBLK:
	    {
	      long min, max;

	      if (! tape_get_feature (TAPE_DRIVE_SET_BLOCK_SIZE))
		{
		  ret = ERROR_INVALID_PARAMETER;
		  break;
		}
	      ret = tape_get_blocksize (&min, NULL, &max, NULL);
	      if (ret)
		  break;
	      if (devbuf && (size_t) op->mt_count == devbufsiz && !varblkop)
		{
		  ret = 0;
		  break;
		}
	      if ((op->mt_count == 0
		   && !tape_get_feature (TAPE_DRIVE_VARIABLE_BLOCK))
		  || (op->mt_count > 0
		      && (op->mt_count < min || op->mt_count > max)))
		{
		  ret = ERROR_INVALID_PARAMETER;
		  break;
		}
	      if (devbuf && op->mt_count > 0
		  && (size_t) op->mt_count < devbufend - devbufstart)
		{
		  ret = ERROR_MORE_DATA;
		  break;
		}
	      if (! (ret = tape_set_blocksize (op->mt_count)))
		{
		  size_t size = 0;
		  if (op->mt_count == 0)
		    {
		      struct mtget get;
		      if ((ret = tape_status (&get)) != NO_ERROR)
			break;
		      size = get.mt_maxblksize;
		      ret = NO_ERROR;
		    }
		  char *buf = NULL;
		  if (size > 1L && !(buf = new char [size]))
		    {
		      ret = ERROR_OUTOFMEMORY;
		      break;
		    }
		  if (devbufsiz > 1L && size > 1L)
		    {
		      memcpy (buf, devbuf + devbufstart,
			      devbufend - devbufstart);
		      devbufend -= devbufstart;
		    }
		  else
		    devbufend = 0;
		  if (devbufsiz > 1L)
		    delete [] devbuf;
		  devbufstart = 0;
		  devbuf = buf;
		  devbufsiz = size;
		  varblkop = op->mt_count == 0;
		}
	    }
	    break;
	  case MTSETDENSITY:
	    ret = ERROR_INVALID_PARAMETER;
	    break;
	  case MTSEEK:
	    if (tape_get_feature (TAPE_DRIVE_ABSOLUTE_BLK))
	      {
		ret = tape_set_pos (TAPE_ABSOLUTE_BLOCK, op->mt_count);
		break;
	      }
	    if (! (ret = tape_get_pos (&block)))
	      {
		ret = tape_set_pos (TAPE_SPACE_RELATIVE_BLOCKS,
				 op->mt_count - block);
	      }
	    break;
	  case MTTELL:
	    if (! (ret = tape_get_pos (&block)))
	      op->mt_count = block;
	    break;
	  case MTSETDRVBUFFER:
	    ret = ERROR_INVALID_PARAMETER;
	    break;
	  case MTFSS:
	    ret = tape_set_pos (TAPE_SPACE_SETMARKS, op->mt_count);
	    break;
	  case MTBSS:
	    ret = tape_set_pos (TAPE_SPACE_SETMARKS, -op->mt_count);
	    break;
	  case MTWSM:
	    ret = tape_write_marks (TAPE_SETMARKS, op->mt_count);
	    break;
	  case MTLOCK:
	    ret = tape_prepare (TAPE_LOCK);
	    break;
	  case MTUNLOCK:
	    ret = tape_prepare (TAPE_UNLOCK);
	    break;
	  case MTLOAD:
	    ret = tape_prepare (TAPE_LOAD);
	    break;
	  case MTUNLOAD:
	    ret = tape_prepare (TAPE_UNLOAD);
	    break;
	  case MTCOMPRESSION:
	    ret = tape_compression (op->mt_count);
	    break;
	  case MTSETPART:
	  case MTMKPART:
	  default:
	    ret = ERROR_INVALID_PARAMETER;
	    break;
	  }
    }
  else if (cmd == MTIOCGET)
    ret = tape_status ((struct mtget *) buf);
  else if (cmd == MTIOCPOS)