Break syslog_channel.c up into syslog_channel.c, syslog_putc.c, syslog_force.c and syslog_flush.c to limited what is brought into the link. Separate syslog_emergstream.c from syslog_stream.c. Didn't help in the case I was looking at.

drivers/syslog/Make.defs

@@ -37,7 +37,8 @@
 ############################################################################
 # Include SYSLOG Infrastructure
 
-CSRCS += vsyslog.c syslog_stream.c syslog_channel.c
+CSRCS += vsyslog.c syslog_stream.c syslog_emergstream.c syslog_channel.c
+CSRCS += syslog_putc.c syslog_force.c syslog_flush.c
 
 ifeq ($(CONFIG_SYSLOG_INTBUFFER),y)
   CSRCS += syslog_intbuffer.c

drivers/syslog/syslog.h

@@ -66,6 +66,11 @@ extern "C"
 #define EXTERN extern
 #endif
 
+/* This is the current syslog channel in use */
+
+struct syslog_channel_s; /* Forward reference */
+FAR const struct syslog_channel_s *g_syslog_channel;
+
 /****************************************************************************
  * Public Function Prototypes
  ****************************************************************************/

drivers/syslog/syslog_channel.c

@@ -43,7 +43,6 @@
 #include <assert.h>
 #include <errno.h>
 
-#include <nuttx/sched.h>
 #include <nuttx/syslog/syslog.h>
 
 #ifdef CONFIG_RAMLOG_SYSLOG
@@ -90,9 +89,13 @@ static const struct syslog_channel_s g_default_channel =
 };
 #endif
 
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
 /* This is the current syslog channel in use */
 
-static FAR const struct syslog_channel_s *g_syslog_channel = &g_default_channel;
+FAR const struct syslog_channel_s *g_syslog_channel = &g_default_channel;
 
 /****************************************************************************
  * Private Functions
@@ -153,137 +156,3 @@ int syslog_channel(FAR const struct syslog_channel_s *channel)
 
   return -EINVAL;
 }
-
-/****************************************************************************
- * Name: syslog_putc
- *
- * Description:
- *   This is the low-level system logging interface.
- *
- * Input Parameters:
- *   ch - The character to add to the SYSLOG (must be positive).
- *
- * Returned Value:
- *   On success, the character is echoed back to the caller.  A negated
- *   errno value is returned on any failure.
- *
- ****************************************************************************/
-
-int syslog_putc(int ch)
-{
-  DEBUGASSERT(g_syslog_channel != NULL);
-
-  /* Is this an attempt to do SYSLOG output from an interrupt handler? */
-
-  if (up_interrupt_context() || sched_idletask())
-    {
-#if defined(CONFIG_SYSLOG_INTBUFFER)
-      /* Buffer the character in the interrupt buffer.  The interrupt buffer
-       * will be flushed before the next normal, non-interrupt SYSLOG output.
-       */
-
-      return syslog_add_intbuffer(ch);
-#else
-      /* Force the character to the SYSLOG device immediately (if possible).
-       * This means that the interrupt data may not be in synchronization
-       * with output data that may have been buffered by sc_putc().
-       */
-
-      DEBUGASSERT(g_syslog_channel->sc_force != NULL);
-
-      return g_syslog_channel->sc_force(ch);
-#endif
-    }
-  else
-    {
-      DEBUGASSERT(g_syslog_channel->sc_putc != NULL);
-
-#ifdef CONFIG_SYSLOG_INTBUFFER
-      /* Flush any characters that may have been added to the interrupt
-       * buffer.
-       */
-
-      (void)syslog_flush_intbuffer(g_syslog_channel, false);
-#endif
-
-      return g_syslog_channel->sc_putc(ch);
-    }
-}
-
-/****************************************************************************
- * Name: syslog_force
- *
- * Description:
- *   This is the low-level system logging interface.  This version forces
- *   the output and is only used in emergency situations (e.g., in assertion
- *   handling).
- *
- * Input Parameters:
- *   ch - The character to add to the SYSLOG (must be positive).
- *
- * Returned Value:
- *   On success, the character is echoed back to the caller.  A negated
- *   errno value is returned on any failure.
- *
- ****************************************************************************/
-
-int syslog_force(int ch)
-{
-  DEBUGASSERT(g_syslog_channel != NULL && g_syslog_channel->sc_force != NULL);
-
-#ifdef CONFIG_SYSLOG_INTBUFFER
-  /* Flush any characters that may have been added to the interrupt
-   * buffer through the emergency channel
-   */
-
-  (void)syslog_flush_intbuffer(g_syslog_channel, true);
-#endif
-
-  /* Then send the character to the emergency channel */
-
-  return g_syslog_channel->sc_force(ch);
-}
-
-/****************************************************************************
- * Name: syslog_flush
- *
- * Description:
- *   This is called by system crash-handling logic.  It must flush any
- *   buffered data to the SYSLOG device.
- *
- *   Interrupts are disabled at the time of the crash and this logic must
- *   perform the flush using low-level, non-interrupt driven logic.
- *
- * Input Parameters:
- *   ch - The character to add to the SYSLOG (must be positive).
- *
- * Returned Value:
- *   Zero (OK)is returned on  success.  A negated errno value is returned
- *   on any failure.
- *
- ****************************************************************************/
-
-#if 0
-/* REVISIT: (1) Not yet integrated into assertion handlers and (2) there is
- * an implementation problem in that if a character driver is the underlying
- * device, then there is no mechanism to flush the data buffered in the
- * driver with interrupts disabled.
- */
-
-int syslog_flush(void)
-{
-  DEBUGASSERT(g_syslog_channel != NULL && g_syslog_channel->sc_flush != NULL);
-
-#ifdef CONFIG_SYSLOG_INTBUFFER
-  /* Flush any characters that may have been added to the interrupt
-   * buffer.
-   */
-
-  (void)syslog_flush_intbuffer(g_syslog_channel, true);
-#endif
-
-  /* Then flush all of the buffered output to the SYSLOG device */
-
-  return g_syslog_channel->sc_flush();
-}
-#endif

drivers/syslog/syslog_emergstream.c

@@ -0,0 +1,116 @@
+/****************************************************************************
+ * drivers/syslog/syslog_emergtream.c
+ *
+ *   Copyright (C) 2016 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_putc returns EOF with the errno value set;
+       */
+
+      ret = syslog_force(ch);
+      if (ret != EOF)
+        {
+          this->nput++;
+          return;
+        }
+
+      /* The special errno value -EINTR means that syslog_putc() was
+       * awakened by a signal.  This is not a real error and must be
+       * ignored in this context.
+       */
+    }
+  while (errno == -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_lowoutstream_s to be initialized.
+ *
+ * Returned Value:
+ *   None (User allocated instance initialized).
+ *
+ ****************************************************************************/
+
+void emergstream(FAR struct lib_outstream_s *stream)
+{
+  stream->put   = emergstream_putc;
+#ifdef CONFIG_STDIO_LINEBUFFER
+  stream->flush = lib_noflush;
+#endif
+  stream->nput  = 0;
+}

drivers/syslog/syslog_flush.c

@@ -0,0 +1,95 @@
+/****************************************************************************
+ * drivers/syslog/syslog_flush.c
+ *
+ *   Copyright (C) 2016 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 <stdbool.h>
+#include <assert.h>
+
+#include <nuttx/syslog/syslog.h>
+
+#include "syslog.h"
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: syslog_flush
+ *
+ * Description:
+ *   This is called by system crash-handling logic.  It must flush any
+ *   buffered data to the SYSLOG device.
+ *
+ *   Interrupts are disabled at the time of the crash and this logic must
+ *   perform the flush using low-level, non-interrupt driven logic.
+ *
+ * Input Parameters:
+ *   ch - The character to add to the SYSLOG (must be positive).
+ *
+ * Returned Value:
+ *   Zero (OK)is returned on  success.  A negated errno value is returned
+ *   on any failure.
+ *
+ ****************************************************************************/
+
+#if 0
+/* REVISIT: (1) Not yet integrated into assertion handlers and (2) there is
+ * an implementation problem in that if a character driver is the underlying
+ * device, then there is no mechanism to flush the data buffered in the
+ * driver with interrupts disabled.
+ */
+
+int syslog_flush(void)
+{
+  DEBUGASSERT(g_syslog_channel != NULL && g_syslog_channel->sc_flush != NULL);
+
+#ifdef CONFIG_SYSLOG_INTBUFFER
+  /* Flush any characters that may have been added to the interrupt
+   * buffer.
+   */
+
+  (void)syslog_flush_intbuffer(g_syslog_channel, true);
+#endif
+
+  /* Then flush all of the buffered output to the SYSLOG device */
+
+  return g_syslog_channel->sc_flush();
+}
+#endif

drivers/syslog/syslog_force.c

@@ -0,0 +1,85 @@
+/****************************************************************************
+ * drivers/syslog/syslog_force.c
+ *
+ *   Copyright (C) 2016 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 <stdbool.h>
+#include <assert.h>
+
+#include <nuttx/syslog/syslog.h>
+
+#include "syslog.h"
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: syslog_force
+ *
+ * Description:
+ *   This is the low-level system logging interface.  This version forces
+ *   the output and is only used in emergency situations (e.g., in assertion
+ *   handling).
+ *
+ * Input Parameters:
+ *   ch - The character to add to the SYSLOG (must be positive).
+ *
+ * Returned Value:
+ *   On success, the character is echoed back to the caller.  A negated
+ *   errno value is returned on any failure.
+ *
+ ****************************************************************************/
+
+int syslog_force(int ch)
+{
+  DEBUGASSERT(g_syslog_channel != NULL && g_syslog_channel->sc_force != NULL);
+
+#ifdef CONFIG_SYSLOG_INTBUFFER
+  /* Flush any characters that may have been added to the interrupt
+   * buffer through the emergency channel
+   */
+
+  (void)syslog_flush_intbuffer(g_syslog_channel, true);
+#endif
+
+  /* Then send the character to the emergency channel */
+
+  return g_syslog_channel->sc_force(ch);
+}

drivers/syslog/syslog_putc.c

@@ -0,0 +1,110 @@
+/****************************************************************************
+ * drivers/syslog/syslog_putc.c
+ *
+ *   Copyright (C) 2016 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 <assert.h>
+#include <errno.h>
+
+#include <nuttx/arch.h>
+#include <nuttx/sched.h>
+#include <nuttx/syslog/syslog.h>
+
+#include "syslog.h"
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: syslog_putc
+ *
+ * Description:
+ *   This is the low-level system logging interface.
+ *
+ * Input Parameters:
+ *   ch - The character to add to the SYSLOG (must be positive).
+ *
+ * Returned Value:
+ *   On success, the character is echoed back to the caller.  A negated
+ *   errno value is returned on any failure.
+ *
+ ****************************************************************************/
+
+int syslog_putc(int ch)
+{
+  DEBUGASSERT(g_syslog_channel != NULL);
+
+  /* Is this an attempt to do SYSLOG output from an interrupt handler? */
+
+  if (up_interrupt_context() || sched_idletask())
+    {
+#if defined(CONFIG_SYSLOG_INTBUFFER)
+      /* Buffer the character in the interrupt buffer.  The interrupt buffer
+       * will be flushed before the next normal, non-interrupt SYSLOG output.
+       */
+
+      return syslog_add_intbuffer(ch);
+#else
+      /* Force the character to the SYSLOG device immediately (if possible).
+       * This means that the interrupt data may not be in synchronization
+       * with output data that may have been buffered by sc_putc().
+       */
+
+      DEBUGASSERT(g_syslog_channel->sc_force != NULL);
+
+      return g_syslog_channel->sc_force(ch);
+#endif
+    }
+  else
+    {
+      DEBUGASSERT(g_syslog_channel->sc_putc != NULL);
+
+#ifdef CONFIG_SYSLOG_INTBUFFER
+      /* Flush any characters that may have been added to the interrupt
+       * buffer.
+       */
+
+      (void)syslog_flush_intbuffer(g_syslog_channel, false);
+#endif
+
+      return g_syslog_channel->sc_putc(ch);
+    }
+}

drivers/syslog/syslog_stream.c

@@ -86,39 +86,6 @@ static void syslogstream_putc(FAR struct lib_outstream_s *this, int ch)
   while (errno == -EINTR);
 }
 
-/****************************************************************************
- * 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_putc returns EOF with the errno value set;
-       */
-
-      ret = syslog_force(ch);
-      if (ret != EOF)
-        {
-          this->nput++;
-          return;
-        }
-
-      /* The special errno value -EINTR means that syslog_putc() was
-       * awakened by a signal.  This is not a real error and must be
-       * ignored in this context.
-       */
-    }
-  while (errno == -EINTR);
-}
-
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -147,28 +114,3 @@ void syslogstream(FAR struct lib_outstream_s *stream)
 #endif
   stream->nput  = 0;
 }
-
-/****************************************************************************
- * 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_lowoutstream_s to be initialized.
- *
- * Returned Value:
- *   None (User allocated instance initialized).
- *
- ****************************************************************************/
-
-void emergstream(FAR struct lib_outstream_s *stream)
-{
-  stream->put   = emergstream_putc;
-#ifdef CONFIG_STDIO_LINEBUFFER
-  stream->flush = lib_noflush;
-#endif
-  stream->nput  = 0;
-}