nuttx/drivers/syslog/syslog_emergstream.c

/****************************************************************************
 * drivers/syslog/syslog_emergtream.c
 *
 *   Copyright (C) 2016-2017 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <stdio.h>
#include <unistd.h>
#include <assert.h>
#include <errno.h>

#include <nuttx/syslog/syslog.h>
#include <nuttx/streams.h>

#include "syslog.h"

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Name: emergstream_putc
 ****************************************************************************/

static void emergstream_putc(FAR struct lib_outstream_s *this, int ch)
{
  int ret;

  /* Try writing until the write was successful or until an irrecoverable
   * error occurs.
   */

  do
    {
      /* Write the character to the supported logging device.  On failure,
       * syslog_force returns a negated errno value.
       */

      ret = syslog_force(ch);
      if (ret >= 0)
        {
          this->nput++;
          return;
        }

      /* The special return value -EINTR means that syslog_force() was
       * awakened by a signal.  This is not a real error and must be
       * ignored in this context.
       */
    }
  while (ret == -EINTR);
}

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: emergstream
 *
 * Description:
 *   Initializes a stream for use with the configured emergency syslog
 *   interface.  Only accessible from with the OS SYSLOG logic.
 *
 * Input Parameters:
 *   stream - User allocated, uninitialized instance of struct
 *            lib_outstream_s to be initialized.
 *
 * Returned Value:
 *   None (User allocated instance initialized).
 *
 ****************************************************************************/

void emergstream(FAR struct lib_outstream_s *stream)
{
  stream->put   = emergstream_putc;
  stream->flush = lib_noflush;
  stream->nput  = 0;
}