nuttx/drivers/syslog/syslog_write.c

/****************************************************************************
 * drivers/syslog/syslog_write.c
 *
 *   Copyright (C) 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 <sys/types.h>

#include <nuttx/arch.h>
#include <nuttx/sched.h>
#include <nuttx/syslog/syslog.h>

#include "syslog.h"

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

/****************************************************************************
 * Name: syslog_default_write
 *
 * Description:
 *   This provides a default write method for syslog devices that do not
 *   support multiple byte writes  This functions simply loops, outputting
 *   one character at a time.
 *
 * Input Parameters:
 *   buffer - The buffer containing the data to be output
 *   buflen - The number of bytes in the buffer
 *
 * Returned Value:
 *   On success, the number of characters written is returned.  A negated
 *   errno value is returned on any failure.
 *
 ****************************************************************************/

static ssize_t syslog_default_write(FAR const char *buffer, size_t buflen)
{
  size_t nwritten;

  if (up_interrupt_context() || sched_idletask())
    {
      for (nwritten = 0; nwritten < buflen; nwritten++)
        {
#ifdef CONFIG_SYSLOG_INTBUFFER
          if (up_interrupt_context())
            {
              syslog_add_intbuffer(*buffer++);
            }
          else
#endif
            {
              DEBUGASSERT(g_syslog_channel->sc_force != NULL);
              g_syslog_channel->sc_force(*buffer++);
            }
        }
    }
#ifdef CONFIG_SYSLOG_WRITE
  else if (g_syslog_channel->sc_write)
    {
      nwritten = g_syslog_channel->sc_write(buffer, buflen);
    }
#endif
  else
    {
      for (nwritten = 0; nwritten < buflen; nwritten++)
        {
          DEBUGASSERT(g_syslog_channel->sc_putc != NULL);
          g_syslog_channel->sc_putc(*buffer++);
        }
    }

  return nwritten;
}

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

/****************************************************************************
 * Name: syslog_write
 *
 * Description:
 *   This is the low-level, multiple character, system logging interface.
 *
 * Input Parameters:
 *   buffer - The buffer containing the data to be output
 *   buflen - The number of bytes in the buffer
 *
 * Returned Value:
 *   On success, the number of characters written is returned.  A negated
 *   errno value is returned on any failure.
 *
 ****************************************************************************/

ssize_t syslog_write(FAR const char *buffer, size_t buflen)
{
#ifdef CONFIG_SYSLOG_INTBUFFER
  if (!up_interrupt_context() && !sched_idletask())
    {
      /* Flush any characters that may have been added to the interrupt
       * buffer.
       */

      syslog_flush_intbuffer(g_syslog_channel, false);
    }
#endif

  return syslog_default_write(buffer, buflen);
}