The initial SYLOG device logic was valiant but yet still not enough

git-svn-id: https://nuttx.svn.sourceforge.net/svnroot/nuttx/trunk@4998 7fd9a85b-ad96-42d3-883c-3090e2eb8679

6 files changed, 482 insertions, 15 deletions

diff --git a/nuttx/fs/Kconfig b/nuttx/fs/Kconfig
index afea33712..1d1046735 100644
--- a/nuttx/fs/Kconfig
+++ b/nuttx/fs/Kconfig
@@ -9,4 +9,33 @@ source fs/fat/Kconfig
 source fs/mmap/Kconfig
 source fs/nfs/Kconfig
 source fs/nxffs/Kconfig
-source fs/romfs/Kconfig
\ No newline at end of file
+source fs/romfs/Kconfig
+
+comment "System Logging"
+
+config SYSLOG
+	bool "System logging"
+	default n
+	---help---
+		Enables generic system logging features.
+
+config SYSLOG_DEVPATH
+	string "System log device"
+	default "/dev/syslog"
+	depends on SYSLOG
+	---help---
+		The full path to the system logging device.  For the RAMLOG SYSLOG device,
+		this is normally "/dev/ramlog".  For character SYSLOG devices, it should be
+		some other existing character device (or file) supported by the configuration
+		(such as "/dev/ttyS1")/
+
+config SYSLOG_CHAR
+	bool "System log character device support"
+	default y
+	depends on SYSLOG
+	---help---
+		Enable the generic character device for the SYSLOG. The full path to the
+		SYSLOG device is provided by SYSLOG_DEVPATH. A valid character device (or
+		file) must exist at this path.  It will by opened by syslog_initialize.
+
+		Do not enable more than one SYSLOG device.
diff --git a/nuttx/fs/Makefile b/nuttx/fs/Makefile
index e03f5c23d..0f01c0a63 100644
--- a/nuttx/fs/Makefile
+++ b/nuttx/fs/Makefile
@@ -1,7 +1,7 @@
 ############################################################################
 # fs/Makefile
 #
-#   Copyright (C) 2007, 2008, 2011 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2007, 2008, 2011-2012 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -79,6 +79,14 @@ ifneq ($(CONFIG_NFILE_STREAMS),0)
 CSRCS		+= fs_fdopen.c 
 endif
 
+# System logging to a character device (or file)
+
+ifeq ($(CONFIG_SYSLOG),y)
+ifeq ($(CONFIG_SYSLOG_CHAR),y)
+CSRCS		+= fs_syslog.c 
+endif
+endif
+
 # Additional files required is mount-able file systems are supported
 
 ifneq ($(CONFIG_DISABLE_MOUNTPOINT),y)
diff --git a/nuttx/fs/fs_files.c b/nuttx/fs/fs_files.c
index d237b17bd..9208b323b 100644
--- a/nuttx/fs/fs_files.c
+++ b/nuttx/fs/fs_files.c
@@ -351,6 +351,7 @@ int files_dup(FAR struct file *filep1, FAR struct file *filep2)
           goto errout_with_inode;
         }
     }
+
   _files_semgive(list);
   return OK;
 
@@ -361,9 +362,11 @@ errout_with_inode:
   filep2->f_oflags = 0;
   filep2->f_pos    = 0;
   filep2->f_inode  = NULL;
+
 errout_with_ret:
   err              = -ret;
   _files_semgive(list);
+
 errout:
   set_errno(err);
   return ERROR;
@@ -398,8 +401,10 @@ int files_allocate(FAR struct inode *inode, int oflags, off_t pos, int minfd)
                return i;
             }
         }
+
       _files_semgive(list);
     }
+
   return ERROR;
 }
 
diff --git a/nuttx/fs/fs_open.c b/nuttx/fs/fs_open.c
index 8b3a81862..ccdb05cef 100644
--- a/nuttx/fs/fs_open.c
+++ b/nuttx/fs/fs_open.c
@@ -79,14 +79,14 @@ int inode_checkflags(FAR struct inode *inode, int oflags)
 
 int open(const char *path, int oflags, ...)
 {
-  struct filelist  *list;
-  FAR struct inode *inode;
-  const char       *relpath = NULL;
+  FAR struct filelist *list;
+  FAR struct inode    *inode;
+  FAR const char      *relpath = NULL;
 #if defined(CONFIG_FILE_MODE) || !defined(CONFIG_DISABLE_MOUNTPOINT)
-  mode_t            mode = 0666;
+  mode_t               mode = 0666;
 #endif
-  int               ret;
-  int               fd;
+  int                  ret;
+  int                  fd;
 
   /* Get the thread-specific file list */
 
@@ -118,9 +118,9 @@ int open(const char *path, int oflags, ...)
   inode = inode_find(path, &relpath);
   if (!inode)
     {
-      /* "O_CREAT is not set and the named file does not exist.  Or,
-       *  a directory component in pathname does not exist or is a
-       *  dangling symbolic link."
+      /* "O_CREAT is not set and the named file does not exist.  Or, a
+       * directory component in pathname does not exist or is a dangling
+       * symbolic link."
        */
 
       ret = ENOENT;
@@ -131,7 +131,11 @@ int open(const char *path, int oflags, ...)
    * specifically exclude block drivers.
    */
 
+#ifndef CONFIG_DISABLE_MOUNTPOINT
   if ((!INODE_IS_DRIVER(inode) && !INODE_IS_MOUNTPT(inode)) || !inode->u.i_ops)
+#else
+  if (!INODE_IS_DRIVER(inode) || !inode->u.i_ops)
+#endif
     {
       ret = ENXIO;
       goto errout_with_inode;
@@ -155,9 +159,9 @@ int open(const char *path, int oflags, ...)
       goto errout_with_inode;
     }
 
-  /* Perform the driver open operation.  NOTE that the open method may
-   * be called many times.  The driver/mountpoint logic should handled this
-   * becuase it may also be closed that many times.
+  /* Perform the driver open operation.  NOTE that the open method may be
+   * called many times.  The driver/mountpoint logic should handled this
+   * because it may also be closed that many times.
    */
 
   ret = OK;
diff --git a/nuttx/fs/fs_syslog.c b/nuttx/fs/fs_syslog.c
new file mode 100644
index 000000000..71207292c
--- /dev/null
+++ b/nuttx/fs/fs_syslog.c
@@ -0,0 +1,421 @@
+/****************************************************************************
+ * fs/syslog.c
+ *
+ *   Copyright (C) 2012 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 <stdint.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <semaphore.h>
+#include <errno.h>
+#include <assert.h>
+
+#include <nuttx/fs/fs.h>
+#include <nuttx/syslog.h>
+
+#include "fs_internal.h"
+
+#if defined(CONFIG_SYSLOG) && defined(CONFIG_SYSLOG_CHAR)
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+ /* Open the device/file write-only, try to create (file) it if it doesn't
+  * exist, if the file that already exists, then append the new log data to
+  * end of the file.
+  */
+
+#define SYSLOG_OFLAGS (O_WRONLY | O_CREAT | O_APPEND)
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/* This enumeration represents the state of the SYSLOG device interface */
+
+enum syslog_state_e
+{
+  SYSLOG_UNINITIALIZED = 0, /* SYSLOG has not been initialized */
+  SYSLOG_BUSY,              /* SYSLOG is not available for this thread */
+  SYSLOG_REOPEN,            /* SYSLOG open failed... try again later */
+  SYSLOG_FAILURE,           /* SYSLOG open failed... don't try again */
+  SYSLOG_OPENED,            /* SYSLOG device is open and ready to use */
+};
+
+/* This structure contains all SYSLOGing state information */
+
+struct syslog_dev_s
+{
+  uint8_t     sl_state;     /* See enum syslog_state_e */
+  sem_t       sl_sem;       /* Enforces mutually exclusive access */
+  struct file sl_file;      /* The syslog file structure */
+};
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/* This is the device structure for the console or syslogging function. */
+
+static struct syslog_dev_s g_sysdev;
+static const uint8_t       g_syscrlf[2]  = { '\r', '\n' };
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: syslog_write
+ *
+ * Description:
+ *   Write to the syslog device
+ *
+ ****************************************************************************/
+
+static inline ssize_t syslog_write(FAR const void *buf, size_t nbytes)
+{
+  FAR struct inode *inode;
+
+  /* Let the driver perform the write */
+
+  inode = g_sysdev.sl_file.f_inode;
+  return inode->u.i_ops->write(&g_sysdev.sl_file, buf, nbytes);
+}
+
+/****************************************************************************
+ * Name: syslog_flush
+ *
+ * Description:
+ *   Flush any buffer data in the file system to media.
+ *
+ ****************************************************************************/
+
+#ifndef CONFIG_DISABLE_MOUNTPOINT
+static inline void syslog_flush(void)
+{
+  FAR struct inode *inode = g_sysdev.sl_file.f_inode;
+
+  /* Is this a mountpoint? Does it support the sync method? */
+
+  if (INODE_IS_MOUNTPT(inode) && inode->u.i_mops->sync)
+    {
+      /* Yes... synchronize to the stream */
+ 
+      (void)inode->u.i_mops->sync(&g_sysdev.sl_file);
+    }
+}
+#endif
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: syslog_initialize
+ *
+ * Description:
+ *   Initialize to use the character device (or file) at
+ *   CONFIG_SYSLOG_DEVPATH as the SYSLOG sink.
+ *
+ *   NOTE that this implementation excludes using a network connection as
+ *   SYSLOG device.  That would be a good extension.
+ *
+ ****************************************************************************/
+
+int syslog_initialize(void)
+{
+  FAR struct inode    *inode;
+  FAR const char      *relpath = NULL;
+  int                  ret;
+
+  /* At this point, the only expected states are SYSLOG_UNINITIALIZED or
+   * SYSLOG_REOPEN..  Not SYSLOG_BUSY, SYSLOG_FAILURE, SYSLOG_OPENED.
+   */
+
+  DEBUGASSERT(g_sysdev.sl_state == SYSLOG_UNINITIALIZED ||
+              g_sysdev.sl_state == SYSLOG_REOPEN);
+
+  g_sysdev.sl_state = SYSLOG_BUSY;
+
+  /* Try to open the device.
+   *
+   * Note that we cannot just call open.  The syslog device must work on all
+   * threads.  Open returns a file descriptor that is valid only for the
+   * task that opened the device (and its pthread children).  Instead, we
+   * essentially re-implement the guts of open() here so that we can get to
+   * the thread-independent structures of the inode.
+   */
+
+  /* Get an inode for this file/device */
+
+  inode = inode_find(CONFIG_SYSLOG_DEVPATH, &relpath);
+  if (!inode)
+    {
+      /* The inode was not found.  In this case, we will attempt to re-open
+       * the device repeatedly.  The assumption is that the device path is
+       * value but that the driver has not yet been registered.
+       */
+
+      g_sysdev.sl_state = SYSLOG_REOPEN;
+      return -ENOENT;
+    }
+
+  /* Verify that the inode is valid and either a character driver or a
+   * mountpoint.
+   */
+
+#ifndef CONFIG_DISABLE_MOUNTPOINT
+  if ((!INODE_IS_DRIVER(inode) && !INODE_IS_MOUNTPT(inode)))
+#else
+  if (!INODE_IS_DRIVER(inode))
+#endif
+    {
+      ret = ENXIO;
+      goto errout_with_inode;
+    }
+
+  /* Make sure that the "entity" at this inode supports write access */
+
+  if (!inode->u.i_ops || !inode->u.i_ops->write)
+    {
+      return -EACCES;
+      goto errout_with_inode;
+    }
+
+  /* Initialize the file structure */
+
+  g_sysdev.sl_file.f_oflags = SYSLOG_OFLAGS;
+  g_sysdev.sl_file.f_pos    = 0;
+  g_sysdev.sl_file.f_inode  = inode;
+
+  /* Perform the low-level open operation. */
+
+  ret = OK;
+  if (inode->u.i_ops->open)
+    {
+      /* Is the inode a mountpoint? */
+
+#ifndef CONFIG_DISABLE_MOUNTPOINT
+      if (INODE_IS_MOUNTPT(inode))
+        {
+          /* Yes.  Open the device write-only, try to create it if it
+           * doesn't exist, if the file that already exists, then append the
+           * new log data to end of the file.
+           */
+
+          ret = inode->u.i_mops->open(&g_sysdev.sl_file, relpath,
+                                      SYSLOG_OFLAGS, 0666);
+        }
+
+      /* No... then it must be a character driver in the NuttX psuedo-
+       * file system.
+       */
+
+      else
+#endif
+        {
+          ret = inode->u.i_ops->open(&g_sysdev.sl_file);
+        }
+    }
+
+  /* Was the file/device successfully opened? */
+
+  if (ret < 0)
+    {
+      ret = -ret;
+      goto errout_with_inode;
+    }
+
+  /* The SYSLOG device is open and ready for writing. */
+
+  sem_init(&g_sysdev.sl_sem, 0, 1);
+  g_sysdev.sl_state = SYSLOG_OPENED;
+  return OK;
+
+ errout_with_inode:
+  g_sysdev.sl_state = SYSLOG_FAILURE;
+  inode_release(inode);
+  return ret;
+}
+
+/****************************************************************************
+ * Name: syslog_putc
+ *
+ * Description:
+ *   This is the low-level system logging interface.  The debugging/syslogging
+ *   interfaces are lib_rawprintf() and lib_lowprinf().  The difference is
+ *   the lib_rawprintf() writes to fd=1 (stdout) and lib_lowprintf() uses
+ *   a lower level interface that works from interrupt handlers.  This
+ *   function is a a low-level interface used to implement lib_lowprintf().
+ *
+ ****************************************************************************/
+
+int syslog_putc(int ch)
+{
+  ssize_t nbytes;
+  int ret;
+
+  /* Ignore any output:
+   *
+   *   (1) Before the SYSLOG device has been initialized.  This could happen
+   *       from debug output that occurs early in the boot sequence before
+   *       syslog_initialize() is called (SYSLOG_UNINITIALIZED_.
+   *   (2) While the device is being initialized.  The case could happen if
+   *       debug output is generated while syslog_initialize() executes
+   *       (SYSLOG_BUSY).
+   *   (2) While we are generating SYSLOG output.  The case could happen if
+   *       debug output is generated while syslog_putc() executes (also
+   *       SYSLOG_BUSY).
+   */
+
+  if (g_sysdev.sl_state == SYSLOG_UNINITIALIZED ||
+      g_sysdev.sl_state == SYSLOG_BUSY)
+    {
+      return -EAGAIN;
+    }
+
+  /* If an irrecoverable failure occurred, then don't bother to try again
+   * (ever)
+   */
+
+  if (g_sysdev.sl_state == SYSLOG_FAILURE)
+    {
+      return -ENXIO;
+    }
+
+  /* syslog_initialize() is called as soon as enough of the operating system
+   * is in place to support the open operation... but it is possible that the
+   * SYSLOG device is not yet registered at that time.  In this case, we
+   * know that the system is sufficiently initialized to support an attempt
+   * to re-open the SYSLOG device.
+   *
+   * NOTE that the scheduler is locked.  That is because we do not have fully
+   * initialized semaphore capability until the SYSLOG device is successfully
+   * initialized
+   */
+
+  sched_lock();
+  if (g_sysdev.sl_state == SYSLOG_REOPEN)
+    {
+      /* 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_intialize() 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).
+       */
+
+      ret = syslog_initialize();
+      if (ret < 0)
+        {
+          sched_unlock();
+          return ret;
+        }
+    }
+
+  sched_unlock();
+  DEBUGASSERT(g_sysdev.sl_state == SYSLOG_OPENED);
+
+  /* Ignore carriage returns */
+
+  if (ch == '\r')
+    {
+      return ch;
+    }
+
+  /* The syslog device is ready for writing and we have something of
+   * value to write.
+   */
+
+  ret = sem_wait(&g_sysdev.sl_sem);
+  if (ret < 0)
+    {
+      return -get_errno();
+    }
+
+  /* Pre-pend a newline with a carriage return.  Setting sl_state to
+   * SYSLOG_BUSY will suppress any recursive debug logic generated by
+   * the syslog_write call.
+   */
+
+  g_sysdev.sl_state == SYSLOG_BUSY;
+  if (ch == '\n')
+    {
+      /* Write the CR-LF sequence */
+
+      nbytes = syslog_write(g_syscrlf, 2);
+
+      /* Synchronize the file when each CR-LF is encountered (i.e.,
+       * implements line buffering always).
+       */
+
+#ifndef CONFIG_DISABLE_MOUNTPOINT
+      if (nbytes > 0)
+        {
+          syslog_flush();
+        }
+#endif
+    }
+  else
+    {
+      /* Write the non-newline character (and don't flush) */
+
+      nbytes = syslog_write(&ch, 1);
+    }
+
+  g_sysdev.sl_state == SYSLOG_OPENED;
+  sem_post(&g_sysdev.sl_sem);
+
+  /* Check if the write was successful */
+
+  if (nbytes < 0)
+    {
+      return nbytes;
+    }
+
+  return ch;
+}
+
+#endif /* CONFIG_SYSLOG && CONFIG_SYSLOG_CHAR */
diff --git a/nuttx/fs/fs_write.c b/nuttx/fs/fs_write.c
index 3b3dd1f76..93dad92c4 100644
--- a/nuttx/fs/fs_write.c
+++ b/nuttx/fs/fs_write.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * fs/fs_write.c
  *
- *   Copyright (C) 2007-2009 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2012 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without