libc/winsup/cygwin/fhandler_raw.cc

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

   Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2011,
   2012, 2013 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 <unistd.h>
#include <cygwin/rdevio.h>
#include <sys/mtio.h>
#include <sys/param.h>
#include "cygerrno.h"
#include "path.h"
#include "fhandler.h"

/**********************************************************************/
/* fhandler_dev_raw */

fhandler_dev_raw::fhandler_dev_raw ()
  : fhandler_base (),
    status ()
{
  need_fork_fixup (true);
}

fhandler_dev_raw::~fhandler_dev_raw ()
{
  if (devbufsiz > 1L)
    delete [] devbufalloc;
}

int __reg2
fhandler_dev_raw::fstat (struct stat *buf)
{
  debug_printf ("here");

  fhandler_base::fstat (buf);
  if (is_auto_device ())
    {
      if (get_major () == DEV_TAPE_MAJOR)
	buf->st_mode = S_IFCHR | STD_RBITS | STD_WBITS | S_IWGRP | S_IWOTH;
      else
	buf->st_mode = S_IFBLK | STD_RBITS | STD_WBITS | S_IWGRP | S_IWOTH;

      buf->st_uid = geteuid32 ();
      buf->st_gid = getegid32 ();
      buf->st_nlink = 1;
      buf->st_blksize = PREFERRED_IO_BLKSIZE;
      time_as_timestruc_t (&buf->st_ctim);
      buf->st_atim = buf->st_mtim = buf->st_birthtim = buf->st_ctim;
    }
  return 0;
}

int
fhandler_dev_raw::open (int flags, mode_t)
{
  /* Check for illegal flags. */
  if (get_major () != DEV_TAPE_MAJOR && (flags & O_APPEND))
    {
      set_errno (EINVAL);
      return 0;
    }

  /* Always open a raw device existing and binary. */
  flags &= ~(O_CREAT | O_TRUNC);
  flags |= O_BINARY;

  /* Write-only doesn't work well with raw devices */
  if ((flags & O_ACCMODE) == O_WRONLY)
    flags = ((flags & ~O_WRONLY) | O_RDWR);

  int res = fhandler_base::open (flags, 0);

  return res;
}

int
fhandler_dev_raw::dup (fhandler_base *child, int flags)
{
  int ret = fhandler_base::dup (child, flags);

  if (!ret)
    {
      fhandler_dev_raw *fhc = (fhandler_dev_raw *) child;

      if (devbufsiz > 1L)
	{
	  /* Create sector-aligned buffer */
	  fhc->devbufalloc = new char [devbufsiz + devbufalign];
	  fhc->devbuf = (char *) roundup2 ((uintptr_t) fhc->devbufalloc,
					   (uintptr_t) devbufalign);
	}
      fhc->devbufstart = 0;
      fhc->devbufend = 0;
      fhc->lastblk_to_read (false);
    }
  return ret;
}

void
fhandler_dev_raw::fixup_after_fork (HANDLE parent)
{
  fhandler_base::fixup_after_fork (parent);
  devbufstart = 0;
  devbufend = 0;
  lastblk_to_read (false);
}

void
fhandler_dev_raw::fixup_after_exec ()
{
  if (!close_on_exec ())
    {
      if (devbufsiz > 1L)
	{
	  /* Create sector-aligned buffer */
	  devbufalloc = new char [devbufsiz + devbufalign];
	  devbuf = (char *) roundup2 ((uintptr_t) devbufalloc,
				      (uintptr_t) devbufalign);
	}
      devbufstart = 0;
      devbufend = 0;
      lastblk_to_read (false);
    }
}

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

  if (cmd == RDIOCDOP)
    {
      struct rdop *op = (struct rdop *) buf;

      if (!op)
	ret = ERROR_INVALID_PARAMETER;
      else
	switch (op->rd_op)
	  {
	  case RDSETBLK:
	    if (get_major () == DEV_TAPE_MAJOR)
	      {
		struct mtop mop;

		mop.mt_op = MTSETBLK;
		mop.mt_count = op->rd_parm;
		ret = ioctl (MTIOCTOP, &mop);
	      }
	    else if ((op->rd_parm <= 1 && get_major () != DEV_TAPE_MAJOR)
		     || (op->rd_parm > 1 && (op->rd_parm % devbufalign))
		     || (get_flags () & O_DIRECT))
	      /* The conditions for a valid parameter are:
		 - The new size is either 0 or 1, both indicating unbuffered
		   I/O, and the device is a tape device.
		 - Or, the new buffersize must be a multiple of the
		   required buffer alignment.
		 - In the O_DIRECT case, the whole request is invalid. */
	      ret = ERROR_INVALID_PARAMETER;
	    else if (!devbuf || op->rd_parm != devbufsiz)
	      {
		char *buf = NULL;
		off_t curpos = lseek (0, SEEK_CUR);

		if (op->rd_parm > 1L)
		  buf = new char [op->rd_parm + devbufalign];

		if (devbufsiz > 1L)
		  delete [] devbufalloc;

		devbufalloc = buf;
		devbuf = (char *) roundup2 ((uintptr_t) buf,
					    (uintptr_t) devbufalign);
		devbufsiz = op->rd_parm ?: 1L;
		devbufstart = devbufend = 0;
		lseek (curpos, SEEK_SET);
	      }
	    break;
	  default:
	    break;
	  }
    }
  else if (cmd == RDIOCGET)
    {
      struct rdget *get = (struct rdget *) buf;

      if (!get)
	ret = ERROR_INVALID_PARAMETER;
      else
	get->bufsiz = devbufsiz;
    }
  else
    return fhandler_base::ioctl (cmd, buf);

  if (ret != NO_ERROR)
    {
      SetLastError (ret);
      __seterrno ();
      return -1;
    }
  return 0;
}