path: root/backend/hp-handle.c

/* sane - Scanner Access Now Easy.
   Copyright (C) 1997 Geoffrey T. Dairiki
   This file is part of the SANE package.

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston,
   MA 02111-1307, USA.

   As a special exception, the authors of SANE give permission for
   additional uses of the libraries contained in this release of SANE.

   The exception is that, if you link a SANE library with other files
   to produce an executable, this does not by itself cause the
   resulting executable to be covered by the GNU General Public
   License.  Your use of that executable is in no way restricted on
   account of linking the SANE library code into it.

   This exception does not, however, invalidate any other reasons why
   the executable file might be covered by the GNU General Public
   License.

   If you submit changes to SANE to the maintainers to be included in
   a subsequent release, you agree by submitting the changes that
   those changes may be distributed with this exception intact.

   If you write modifications of your own for SANE, it is your choice
   whether to permit this exception to apply to your modifications.
   If you do not wish that, delete this exception notice.

   This file is part of a SANE backend for HP Scanners supporting
   HP Scanner Control Language (SCL).
*/

/* #define STUBS
extern int sanei_debug_hp; */
#define DEBUG_DECLARE_ONLY
#include "../include/sane/config.h"

#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#include <string.h>
#include <signal.h>
#include "../include/lassert.h"
#include <errno.h>
#include <fcntl.h>
#include <sys/wait.h>

#include "hp-handle.h"

#include "../include/sane/sanei_backend.h"
#include "../include/sane/sanei_thread.h"

#include "hp-device.h"
#include "hp-option.h"
#include "hp-accessor.h"
#include "hp-scsi.h"
#include "hp-scl.h"

struct hp_handle_s
{
    HpData		data;
    HpDevice		dev;
    SANE_Parameters	scan_params;

    SANE_Pid		reader_pid;
    int			child_forked; /* Flag if we used fork() or not */
    size_t		bytes_left;
    int			pipe_read_fd;
    sigset_t            sig_set;

    sig_atomic_t	cancelled;

    /* These data are used by the child */
    HpScsi      scsi;
    HpProcessData procdata;
    int			pipe_write_fd;
};


static hp_bool_t
hp_handle_isScanning (HpHandle this)
{
  return this->reader_pid != 0;
}

/*
 * reader thread. Used when threads are used
 */
static int
reader_thread (void *data)
{
  struct hp_handle_s *this = (struct hp_handle_s *) data;
  struct SIGACTION	act;
  SANE_Status status;

  DBG (1, "reader_thread: thread started\n"
   "  parameters: scsi = 0x%08lx, pipe_write_fd = %d\n",
          (long) this->scsi, this->pipe_write_fd);

  memset(&act, 0, sizeof(act));
  sigaction(SIGTERM, &act, 0);

  DBG (1, "Starting sanei_hp_scsi_pipeout()\n");
  status = sanei_hp_scsi_pipeout (this->scsi, this->pipe_write_fd,
                                  &(this->procdata));
  DBG (1, "sanei_hp_scsi_pipeout finished with %s\n", sane_strstatus (status));

  close (this->pipe_write_fd);
  this->pipe_write_fd = -1;
  sanei_hp_scsi_destroy (this->scsi, 0);
  return status;
}

/*
 * reader process. Used when forking child.
 */
static int
reader_process (void *data)
{
  struct hp_handle_s *this = (struct hp_handle_s *) data;
  struct SIGACTION	sa;
  SANE_Status status;

  /* Here we are in a forked child. The thread will not come up to here. */
  /* Forked child must close read end of pipe */
  close (this->pipe_read_fd);
  this->pipe_read_fd = -1;

  memset(&sa, 0, sizeof(sa));
  sa.sa_handler = SIG_DFL;
  sigaction(SIGTERM, &sa, 0);
  sigdelset(&(this->sig_set), SIGTERM);
  sigprocmask(SIG_SETMASK, &(this->sig_set), 0);

  /* not closing writing end of pipe gives an infinite loop on Digital UNIX */
  status = sanei_hp_scsi_pipeout (this->scsi, this->pipe_write_fd,
                                  &(this->procdata));
  close (this->pipe_write_fd);
  this->pipe_write_fd = -1;
  DBG(3,"reader_process: Exiting child (%s)\n",sane_strstatus(status));
  return (status);
}

static SANE_Status
hp_handle_startReader (HpHandle this, HpScsi scsi)
{
  int	fds[2];
  sigset_t 		old_set;

  assert(this->reader_pid == 0);
  this->cancelled = 0;
  this->pipe_write_fd = this->pipe_read_fd = -1;

  if (pipe(fds))
      return SANE_STATUS_IO_ERROR;

  sigfillset(&(this->sig_set));
  sigprocmask(SIG_BLOCK, &(this->sig_set), &old_set);

  this->scsi = scsi;
  this->pipe_write_fd = fds[1];
  this->pipe_read_fd = fds[0];

  /* Will childs be forked ? */
  this->child_forked = sanei_thread_is_forked ();

  /* Start a thread or fork a child. None of them will return here. */
  /* Returning means to be in the parent or thread/fork failed */
  this->reader_pid = sanei_thread_begin (this->child_forked ? reader_process :
                                         reader_thread, (void *) this);
  if (this->reader_pid != 0)
    {
      /* Here we are in the parent */
      sigprocmask(SIG_SETMASK, &old_set, 0);

      if ( this->child_forked )
      { /* After fork(), parent must close writing end of pipe */
        DBG(3, "hp_handle_startReader: parent closes write end of pipe\n");
        close (this->pipe_write_fd);
        this->pipe_write_fd = -1;
      }

      if (!sanei_thread_is_valid (this->reader_pid))
	{
          if ( !this->child_forked )
          {
            close (this->pipe_write_fd);
            this->pipe_write_fd = -1;
          }
	  close (this->pipe_read_fd);
          this->pipe_read_fd = -1;

          DBG(1, "hp_handle_startReader: fork() failed\n");

	  return SANE_STATUS_IO_ERROR;
	}

      DBG(1, "start_reader: reader process %ld started\n", (long) this->reader_pid);
      return SANE_STATUS_GOOD;
    }

  DBG(3, "Unexpected return from sanei_thread_begin()\n");
  return SANE_STATUS_INVAL;
}

static SANE_Status
hp_handle_stopScan (HpHandle this)
{
  HpScsi	scsi;

  this->cancelled = 0;
  this->bytes_left = 0;

  if (this->reader_pid)
    {
      int info;
      DBG(3, "hp_handle_stopScan: killing child (%ld)\n", (long) this->reader_pid);
      sanei_thread_kill (this->reader_pid);
      sanei_thread_waitpid(this->reader_pid, &info);

      DBG(1, "hp_handle_stopScan: child %s = %d\n",
	  WIFEXITED(info) ? "exited, status" : "signalled, signal",
	  WIFEXITED(info) ? WEXITSTATUS(info) : WTERMSIG(info));
      close(this->pipe_read_fd);
      this->reader_pid = 0;

      if ( !FAILED( sanei_hp_scsi_new(&scsi, this->dev->sanedev.name)) )
      {
        if (WIFSIGNALED(info))
	{
	  /*
	  sanei_hp_scl_set(scsi, SCL_CLEAR_ERRORS, 0);
	  sanei_hp_scl_errcheck(scsi);
	  */
	  sanei_hp_scl_reset(scsi);
        }
	sanei_hp_scsi_destroy(scsi,0);
      }
    }
    else
    {
      DBG(3, "hp_handle_stopScan: no pid for child\n");
    }
  return SANE_STATUS_GOOD;
}

static SANE_Status
hp_handle_uploadParameters (HpHandle this, HpScsi scsi, int *scan_depth,
                            hp_bool_t *soft_invert, hp_bool_t *out8)
{
  SANE_Parameters * p	 = &this->scan_params;
  int data_width;
  enum hp_device_compat_e compat;

  assert(scsi);

  *soft_invert = 0;
  *out8 = 0;

  p->last_frame = SANE_TRUE;
  /* inquire resulting size of image after setting it up */
  RETURN_IF_FAIL( sanei_hp_scl_inquire(scsi, SCL_PIXELS_PER_LINE,
				 &p->pixels_per_line,0,0) );
  RETURN_IF_FAIL( sanei_hp_scl_inquire(scsi, SCL_BYTES_PER_LINE,
				 &p->bytes_per_line,0,0) );
  RETURN_IF_FAIL( sanei_hp_scl_inquire(scsi, SCL_NUMBER_OF_LINES,
				 &p->lines,0,0));
  RETURN_IF_FAIL( sanei_hp_scl_inquire(scsi, SCL_DATA_WIDTH,
                                &data_width,0,0));

  switch (sanei_hp_optset_scanmode(this->dev->options, this->data)) {
  case HP_SCANMODE_LINEART: /* Lineart */
  case HP_SCANMODE_HALFTONE: /* Halftone */
      p->format = SANE_FRAME_GRAY;
      p->depth  = 1;
      *scan_depth = 1;

      /* The OfficeJets don't seem to handle SCL_INVERSE_IMAGE, so we'll
       * have to invert in software. */
      if ((sanei_hp_device_probe (&compat, scsi) == SANE_STATUS_GOOD)
          && (compat & HP_COMPAT_OJ_1150C)) {
           *soft_invert=1;
      }

      break;
  case HP_SCANMODE_GRAYSCALE: /* Grayscale */
      p->format = SANE_FRAME_GRAY;
      p->depth  = (data_width > 8) ? 16 : 8;
      *scan_depth = data_width;

      /* 8 bit output forced ? */
      if ( *scan_depth > 8 )
      {
        *out8 = sanei_hp_optset_output_8bit (this->dev->options, this->data);
        DBG(1,"hp_handle_uploadParameters: out8=%d\n", (int)*out8);
        if (*out8)
        {
          p->depth = 8;
          p->bytes_per_line /= 2;
        }
      }
      break;
  case HP_SCANMODE_COLOR: /* RGB */
      p->format = SANE_FRAME_RGB;
      p->depth  = (data_width > 24) ? 16 : 8;
      *scan_depth = data_width / 3;

      /* 8 bit output forced ? */
      if ( *scan_depth > 8 )
      {
        *out8 = sanei_hp_optset_output_8bit (this->dev->options, this->data);
        DBG(1,"hp_handle_uploadParameters: out8=%d\n", (int)*out8);
        if (*out8)
        {
          p->depth = 8;
          p->bytes_per_line /= 2;
        }
      }
      /* HP PhotoSmart does not invert when depth > 8. Lets do it by software */
      if (   (*scan_depth > 8)
          && (sanei_hp_device_probe (&compat, scsi) == SANE_STATUS_GOOD)
          && (compat & HP_COMPAT_PS) )
        *soft_invert = 1;
      DBG(1, "hp_handle_uploadParameters: data width %d\n", data_width);
      break;
  default:
      assert(!"Aack");
      return SANE_STATUS_INVAL;
  }

  return SANE_STATUS_GOOD;
}



HpHandle
sanei_hp_handle_new (HpDevice dev)
{
  HpHandle new	= sanei_hp_allocz(sizeof(*new));

  if (!new)
      return 0;

  if (!(new->data = sanei_hp_data_dup(dev->data)))
    {
      sanei_hp_free(new);
      return 0;
    }

  new->dev = dev;
  return new;
}

void
sanei_hp_handle_destroy (HpHandle this)
{
  HpScsi scsi=0;

  DBG(3,"sanei_hp_handle_destroy: stop scan\n");

  hp_handle_stopScan(this);

  if (sanei_hp_scsi_new(&scsi,this->dev->sanedev.name)==SANE_STATUS_GOOD &&
      scsi) {
	sanei_hp_scsi_destroy(scsi,1);
  }

  sanei_hp_data_destroy(this->data);
  sanei_hp_free(this);
}

const SANE_Option_Descriptor *
sanei_hp_handle_saneoption (HpHandle this, SANE_Int optnum)
{
  if (this->cancelled)
  {
    DBG(1, "sanei_hp_handle_saneoption: cancelled. Stop scan\n");
    hp_handle_stopScan(this);
  }
  return sanei_hp_optset_saneoption(this->dev->options, this->data, optnum);
}

SANE_Status
sanei_hp_handle_control(HpHandle this, SANE_Int optnum,
		  SANE_Action action, void *valp, SANE_Int *info)
{
  SANE_Status status;
  HpScsi  scsi;
  hp_bool_t immediate;

  if (this->cancelled)
  {
    DBG(1, "sanei_hp_handle_control: cancelled. Stop scan\n");
    RETURN_IF_FAIL( hp_handle_stopScan(this) );
  }

  if (hp_handle_isScanning(this))
    return SANE_STATUS_DEVICE_BUSY;

  RETURN_IF_FAIL( sanei_hp_scsi_new(&scsi, this->dev->sanedev.name) );

  immediate = sanei_hp_optset_isImmediate(this->dev->options, optnum);

  status = sanei_hp_optset_control(this->dev->options, this->data,
                                   optnum, action, valp, info, scsi,
                                   immediate);
  sanei_hp_scsi_destroy ( scsi,0 );

  return status;
}

SANE_Status
sanei_hp_handle_getParameters (HpHandle this, SANE_Parameters *params)
{
  SANE_Status   status;

  if (!params)
      return SANE_STATUS_GOOD;

  if (this->cancelled)
  {
    DBG(1, "sanei_hp_handle_getParameters: cancelled. Stop scan\n");
    RETURN_IF_FAIL( hp_handle_stopScan(this) );
  }

  if (hp_handle_isScanning(this))
    {
      *params = this->scan_params;
      return SANE_STATUS_GOOD;
    }

  status = sanei_hp_optset_guessParameters(this->dev->options,
                                           this->data, params);
#ifdef INQUIRE_AFTER_SCAN
  /* Photosmart: this gives the correct number of lines when doing
     an update of the SANE parameters right after a preview */
  if (!strcmp("C5100A", this->dev->sanedev.model)) {
      HpScsi        scsi;
      SANE_Parameters * p    = &this->scan_params;

    if (!FAILED( sanei_hp_scsi_new(&scsi, this->dev->sanedev.name) )) {
      RETURN_IF_FAIL( sanei_hp_scl_inquire(scsi, SCL_NUMBER_OF_LINES,
           &p->lines,0,0));
      sanei_hp_scsi_destroy(scsi,0);
      *params = this->scan_params;
    }
  }
#endif
  return status;
}

SANE_Status
sanei_hp_handle_startScan (HpHandle this)
{
  SANE_Status	status;
  HpScsi	scsi;
  HpScl         scl;
  HpProcessData *procdata = &(this->procdata);
  int           adfscan;

  /* FIXME: setup preview mode stuff? */

  if (hp_handle_isScanning(this))
  {
      DBG(3,"sanei_hp_handle_startScan: Stop current scan\n");
      RETURN_IF_FAIL( hp_handle_stopScan(this) );
  }

  RETURN_IF_FAIL( sanei_hp_scsi_new(&scsi, this->dev->sanedev.name) );

  status = sanei_hp_optset_download(this->dev->options, this->data, scsi);

  if (!FAILED(status))
     status = hp_handle_uploadParameters(this, scsi,
                                         &(procdata->bits_per_channel),
                                         &(procdata->invert),
                                         &(procdata->out8));

  if (FAILED(status))
    {
      sanei_hp_scsi_destroy(scsi,0);
      return status;
    }

  procdata->mirror_vertical =
     sanei_hp_optset_mirror_vert (this->dev->options, this->data, scsi);
  DBG(1, "start: %s to mirror image vertically\n", procdata->mirror_vertical ?
         "Request" : "No request" );

  scl = sanei_hp_optset_scan_type (this->dev->options, this->data);
  adfscan = (scl ==  SCL_ADF_SCAN);

  /* For ADF scan we should check if there is paper available */
  if ( adfscan )
  {int adfstat = 0;
   int can_check_paper = 0;
   int is_flatbed = 0;
   int minval, maxval;

    /* For ADF-support, we have three different types of scanners:
     * ScanJet, ScanJet+, IIp, 3p:
     *   scroll feed, no support for inquire paper in ADF, unload document
     *   and preload document
     * IIc, IIcx, 3c, 4c, 6100C, 4p:
     *   flatbed, no support for preload document
     * 5100C, 5200C, 6200C, 6300C:
     *   scroll feed.
     * For all scroll feed types, we use the usual scan window command.
     * For flatbed types, use a sequence of special commands.
     */

    /* Check the IIp group */
    if (   (sanei_hp_device_support_get (this->dev->sanedev.name,
                                       SCL_UNLOAD, &minval, &maxval)
              != SANE_STATUS_GOOD )
        && (sanei_hp_device_support_get (this->dev->sanedev.name,
                                       SCL_CHANGE_DOC, &minval, &maxval)
              != SANE_STATUS_GOOD ) )
    {
      DBG(3, "start: Request for ADF scan without support of unload doc\n");
      DBG(3, "       and change doc. Seems to be something like a IIp.\n");
      DBG(3, "       Use standard scan window command.\n");

      scl = SCL_START_SCAN;
      can_check_paper = 0;
      is_flatbed = 0;
    }
/*
    else if ( sanei_hp_device_support_get (this->dev->sanedev.name,
                                       SCL_PRELOAD_ADF, &minval, &maxval)
              != SANE_STATUS_GOOD )
*/
    else if ( sanei_hp_is_flatbed_adf (scsi) )
    {
      DBG(3, "start: Request for ADF scan without support of preload doc.\n");
      DBG(3, "       Seems to be a flatbed ADF.\n");
      DBG(3, "       Use ADF scan window command.\n");

      can_check_paper = 1;
      is_flatbed = 1;
    }
    else
    {
      DBG(3, "start: Request for ADF scan with support of preload doc.\n");
      DBG(3, "       Seems to be a scroll feed ADF.\n");
      DBG(3, "       Use standard scan window command.\n");

      scl = SCL_START_SCAN;
      can_check_paper = 1;
      is_flatbed = 0;
    }

    /* Check if the ADF is ready */
    if (  sanei_hp_scl_inquire(scsi, SCL_ADF_READY, &adfstat, 0, 0)
            != SANE_STATUS_GOOD )
    {
      DBG(1, "start: Error checking if ADF is ready\n");
      sanei_hp_scsi_destroy(scsi,0);
      return SANE_STATUS_UNSUPPORTED;
    }

    if ( adfstat != 1 )
    {
      DBG(1, "start: ADF is not ready. Finished.\n");
      sanei_hp_scsi_destroy(scsi,0);
      return SANE_STATUS_NO_DOCS;
    }

    /* Check paper in ADF */
    if ( can_check_paper )
    {
      if (  sanei_hp_scl_inquire(scsi, SCL_ADF_BIN, &adfstat, 0, 0)
              != SANE_STATUS_GOOD )
      {
        DBG(1, "start: Error checking if paper in ADF\n");
        sanei_hp_scsi_destroy(scsi,0);
        return SANE_STATUS_UNSUPPORTED;
      }

      if ( adfstat != 1 )
      {
        DBG(1, "start: No paper in ADF bin. Finished.\n");
        sanei_hp_scsi_destroy(scsi,0);
        return SANE_STATUS_NO_DOCS;
      }

      if ( is_flatbed )
      {
        if ( sanei_hp_scl_set(scsi, SCL_CHANGE_DOC, 0) != SANE_STATUS_GOOD )
        {
          DBG(1, "start: Error changing document\n");
          sanei_hp_scsi_destroy(scsi,0);
          return SANE_STATUS_UNSUPPORTED;
        }
      }
    }
  }

  DBG(1, "start: %s to mirror image vertically\n", procdata->mirror_vertical ?
         "Request" : "No request" );

  this->bytes_left = ( this->scan_params.bytes_per_line
  		       * this->scan_params.lines );

  DBG(1, "start: %d pixels per line, %d bytes per line, %d lines high\n",
      this->scan_params.pixels_per_line, this->scan_params.bytes_per_line,
      this->scan_params.lines);
  procdata->bytes_per_line = (int)this->scan_params.bytes_per_line;
  if (procdata->out8)
  {
    procdata->bytes_per_line *= 2;
    DBG(1,"(scanner will send %d bytes per line, 8 bit output forced)\n",
        procdata->bytes_per_line);
  }
  procdata->lines = this->scan_params.lines;

  /* Wait for front-panel button push ? */
  status = sanei_hp_optset_start_wait(this->dev->options, this->data);

  if (status)   /* Wait for front button push ? Start scan in reader process */
  {
    procdata->startscan = scl;
    status = SANE_STATUS_GOOD;
  }
  else
  {
    procdata->startscan = 0;
    status = sanei_hp_scl_startScan(scsi, scl);
  }

  if (!FAILED( status ))
  {
      status = hp_handle_startReader(this, scsi);
  }

  /* Close SCSI-connection in forked environment */
  if (this->child_forked)
    sanei_hp_scsi_destroy(scsi,0);

  return status;
}


SANE_Status
sanei_hp_handle_read (HpHandle this, void * buf, size_t *lengthp)
{
  ssize_t	nread;
  SANE_Status	status;

  DBG(3, "sanei_hp_handle_read: trying to read %lu bytes\n",
      (unsigned long) *lengthp);

  if (!hp_handle_isScanning(this))
    {
      DBG(1, "sanei_hp_handle_read: not scanning\n");
      return SANE_STATUS_INVAL;
    }

  if (this->cancelled)
    {
      DBG(1, "sanei_hp_handle_read: cancelled. Stop scan\n");
      RETURN_IF_FAIL( hp_handle_stopScan(this) );
      return SANE_STATUS_CANCELLED;
    }

  if (*lengthp == 0)
      return SANE_STATUS_GOOD;

  if (*lengthp > this->bytes_left)
      *lengthp = this->bytes_left;

  if ((nread = read(this->pipe_read_fd, buf, *lengthp)) < 0)
    {
      *lengthp = 0;
      if (errno == EAGAIN)
	  return SANE_STATUS_GOOD;
      DBG(1, "sanei_hp_handle_read: read from pipe: %s. Stop scan\n",
          strerror(errno));
      hp_handle_stopScan(this);
      return SANE_STATUS_IO_ERROR;
    }

  this->bytes_left -= (*lengthp = nread);

  if (nread > 0)
    {
      DBG(3, "sanei_hp_handle_read: read %lu bytes\n", (unsigned long) nread);
      return SANE_STATUS_GOOD;
    }

  DBG(1, "sanei_hp_handle_read: EOF from pipe. Stop scan\n");
  status = this->bytes_left ? SANE_STATUS_IO_ERROR : SANE_STATUS_EOF;
  RETURN_IF_FAIL( hp_handle_stopScan(this) );

  /* Switch off lamp and check unload after scan */
  if (status == SANE_STATUS_EOF)
  {
    const HpDeviceInfo *hpinfo;
    HpScsi scsi;

    if ( sanei_hp_scsi_new(&scsi, this->dev->sanedev.name) == SANE_STATUS_GOOD )
    {
      hpinfo = sanei_hp_device_info_get ( this->dev->sanedev.name );

      if ( hpinfo )
      {
        if ( hpinfo->unload_after_scan )
          sanei_hp_scl_set(scsi, SCL_UNLOAD, 0);
      }

      sanei_hp_scsi_destroy(scsi,0);
    }
  }
  return status;
}

void
sanei_hp_handle_cancel (HpHandle this)
{
  this->cancelled = 1;
  /* The OfficeJet K series may not deliver enough data. */
  /* Therefore the read might not return until it is interrupted. */
  DBG(3,"sanei_hp_handle_cancel: compat flags: 0x%04x\n",
      (int)this->dev->compat);
  if (    (this->reader_pid)
       && (this->dev->compat & HP_COMPAT_OJ_1150C) )
  {
     DBG(3,"sanei_hp_handle_cancel: send SIGTERM to child (%ld)\n",
         (long) this->reader_pid);
     sanei_thread_kill(this->reader_pid);
  }
}

SANE_Status
sanei_hp_handle_setNonblocking (HpHandle this, hp_bool_t non_blocking)
{
  if (!hp_handle_isScanning(this))
      return SANE_STATUS_INVAL;

  if (this->cancelled)
    {
      DBG(3,"sanei_hp_handle_setNonblocking: cancelled. Stop scan\n");
      RETURN_IF_FAIL( hp_handle_stopScan(this) );
      return SANE_STATUS_CANCELLED;
    }

  if (fcntl(this->pipe_read_fd, F_SETFL, non_blocking ? O_NONBLOCK : 0) < 0)
      return SANE_STATUS_IO_ERROR;

  return SANE_STATUS_GOOD;
}

SANE_Status
sanei_hp_handle_getPipefd (HpHandle this, SANE_Int *fd)
{
  if (! hp_handle_isScanning(this))
      return SANE_STATUS_INVAL;

  if (this->cancelled)
    {
      DBG(3,"sanei_hp_handle_getPipefd: cancelled. Stop scan\n");
      RETURN_IF_FAIL( hp_handle_stopScan(this) );
      return SANE_STATUS_CANCELLED;
    }

  *fd = this->pipe_read_fd;
  return SANE_STATUS_GOOD;
}