drivers/syslog/syslog_device.c: Fix assert that assumes re-opened syslog file is the same. Logic in syslog_file_channel() is calling syslog_initialize() for the default syslog device as a recovery action after failed syslog_dev_initialize().

drivers/syslog/Kconfig

@@ -162,7 +162,7 @@ config RAMLOG_SYSLOG
 		Use the RAM logging device for the syslogging interface.  If this
 		feature is enabled (along with SYSLOG), then all debug output (only)
 		will be re-directed to the circular buffer in RAM.  This RAM log can
-		be viewed from NSH using the 'dmesg'command.
+		be viewed from NSH using the 'dmesg' command.
 
 config SYSLOG_CONSOLE
 	bool "Log to /dev/console"

drivers/syslog/README.txt

@@ -116,7 +116,7 @@ SYSLOG Channels
   SYSLOG Channel Interfaces
   -------------------------
   In the NuttX SYSLOG implementation, the underlying device logic the
-  supports the SYSLOG output is referred to as a SYSLOG channel//.  Each
+  supports the SYSLOG output is referred to as a SYSLOG channel.  Each
   SYSLOG channel is represented by an interface defined in
   include/nuttx/syslog/syslog.h:
 
@@ -196,7 +196,7 @@ SYSLOG Channels
 
   Description:
 
-    One power up, the SYSLOG facility is non-existent or limited to very
+    On power up, the SYSLOG facility is non-existent or limited to very
     low-level output.  This function is called later in the initialization
     sequence after full driver support has been initialized.  It installs
     the configured SYSLOG drivers and enables full SYSLOGing capability.
@@ -354,7 +354,7 @@ SYSLOG Channel Options
   /dev/ttyS0.
 
   This SYSLOG device channel is selected with CONFIG_SYSLOG_CHAR and has no
-  other dependencies.  Differences fromthe SYSLOG console channel include:
+  other dependencies.  Differences from the SYSLOG console channel include:
 
     * CONFIG_SYSLOG_DEVPATH.  This configuration option string must be set
       provide the full path to the character device to be used.
@@ -399,8 +399,8 @@ SYSLOG Channel Options
 
     This tiny function is simply a wrapper around syslog_dev_initialize()
     and syslog_channel().  It calls syslog_dev_initialize() to configure
-    the character file at 'devpath then calls syslog_channel() to use that
+    the character file at 'devpath' and then calls syslog_channel() to use
-    device as the SYSLOG output channel.
+    that device as the SYSLOG output channel.
 
     File SYSLOG channels differ from other SYSLOG channels in that they
     cannot be established until after fully booting and mounting the target

drivers/syslog/syslog_device.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * drivers/syslog/syslog_device.c
  *
- *   Copyright (C) 2012, 2016-2017 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2012, 2016-2017, 2019 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -232,9 +232,9 @@ static int syslog_dev_outputready(void)
 
       if (g_syslog_dev.sl_state == SYSLOG_UNINITIALIZED ||
           g_syslog_dev.sl_state == SYSLOG_INITIALIZING)
-       {
+        {
-         return -EAGAIN; /* Can't access the SYSLOG now... maybe next time? */
+          return -EAGAIN; /* Can't access the SYSLOG now... maybe next time? */
-       }
+        }
 
       /* Case (6) */
 
@@ -259,7 +259,7 @@ static int syslog_dev_outputready(void)
         {
           /* Try again to initialize the device.  We may do this repeatedly
            * because the log device might be something that was not ready
-           * the first time that syslog_dev_initializee() was called (such as a
+           * the first time that syslog_dev_initialize() was called (such as a
            * USB serial device that has not yet been connected or a file in
            * an NFS mounted file system that has not yet been mounted).
            */
@@ -332,25 +332,37 @@ int syslog_dev_initialize(FAR const char *devpath, int oflags, int mode)
   if (g_syslog_dev.sl_state == SYSLOG_REOPEN)
     {
       /* Re-opening: Then we should already have a copy of the path to the
-       * device.
+       * device. But that may be for a different device if we revert back
+       * to old syslog destination after the previous attempt failed.
        */
 
-      DEBUGASSERT(g_syslog_dev.sl_devpath != NULL &&
+      DEBUGASSERT(g_syslog_dev.sl_devpath != NULL);
-                  strcmp(g_syslog_dev.sl_devpath, devpath) == 0);
     }
   else
     {
-      /* Initializing.  Copy the device path so that we can use it if we
+      /* Initializing. We do not have the device path yet. */
-       * have to re-open the file.
-       */
 
       DEBUGASSERT(g_syslog_dev.sl_devpath == NULL);
-      g_syslog_dev.sl_oflags  = oflags;
-      g_syslog_dev.sl_mode    = mode;
-      g_syslog_dev.sl_devpath = strdup(devpath);
-      DEBUGASSERT(g_syslog_dev.sl_devpath != NULL);
     }
 
+  /* Copy the device path so that we can use it if we
+   * have to re-open the file.
+   */
+
+  g_syslog_dev.sl_oflags  = oflags;
+  g_syslog_dev.sl_mode    = mode;
+  if (g_syslog_dev.sl_devpath != devpath)
+    {
+      if (g_syslog_dev.sl_devpath != NULL)
+        {
+          kmm_free(g_syslog_dev.sl_devpath);
+        }
+
+      g_syslog_dev.sl_devpath = strdup(devpath);
+    }
+
+  DEBUGASSERT(g_syslog_dev.sl_devpath != NULL);
+
   g_syslog_dev.sl_state = SYSLOG_INITIALIZING;
 
   /* Open the device driver. */
@@ -508,8 +520,8 @@ ssize_t syslog_dev_write(FAR const char *buffer, size_t buflen)
                * - endptr points to the special character.
                */
 
-               writelen = (size_t)((uintptr_t)endptr - (uintptr_t)buffer);
+              writelen = (size_t)((uintptr_t)endptr - (uintptr_t)buffer);
-               if (writelen > 0)
+              if (writelen > 0)
                 {
                   nwritten = file_write(&g_syslog_dev.sl_file, buffer, writelen);
                   if (nwritten < 0)

include/nuttx/syslog/syslog.h

@@ -50,14 +50,16 @@
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
+
 /* Configuration ************************************************************/
+
 /* CONFIG_SYSLOG_INTBUFFER - Enables an interrupt buffer that will be used
  *   to serialize debug output from interrupt handlers.
  * CONFIG_SYSLOG_INTBUFSIZE - The size of the interrupt buffer in bytes.
  * CONFIG_SYSLOG_DEVPATH - The full path to the system logging device
  *
  * In addition, some SYSLOG device must also be enabled that will provide
- * the syslog output "channel.  As of this writing, there are two SYSLOG
+ * the syslog output channel.  As of this writing, there are two SYSLOG
  * devices available:
  *
  *   1. A RAM SYSLOGing device that will log data into a circular buffer
@@ -99,7 +101,7 @@
 
 enum syslog_init_e
 {
-  SYSLOG_INIT_RESET = 0, /* Power on SYSLOG initializaton phase */
+  SYSLOG_INIT_RESET = 0, /* Power on SYSLOG initialization phase */
   SYSLOG_INIT_EARLY,     /* Early initialization in up_initialize() */
   SYSLOG_INIT_LATE       /* Late initialization in nx_start(). */
 };