Syslog buffering: Various corrections from early debug

drivers/syslog/syslog_device.c

@@ -484,6 +484,7 @@ ssize_t syslog_dev_write(FAR const char *buffer, size_t buflen)
   FAR const char *endptr;
   ssize_t nwritten;
   size_t writelen;
+  size_t remaining;
   int errcode;
   int ret;
 
@@ -513,80 +514,57 @@ ssize_t syslog_dev_write(FAR const char *buffer, size_t buflen)
 
   /* Loop until we have output all characters */
 
-  for (endptr = buffer; *endptr != '\n'; endptr++)
+  for (endptr = buffer, remaining = buflen;
+       remaining > 0;
+       endptr++, remaining--)
     {
-      switch (*endptr)
+      /* Special case carriage return and line feed */
+
+      if (*endptr == '\r' || *endptr == '\n')
         {
-          case '\r':
+          /* Write everything up to this point, ignore the special
+           * character.
+           *
+           * - buffer points to next byte to output.
+           * - endptr points to the special character.
+           */
+
+           writelen = (size_t)((uintptr_t)endptr - (uintptr_t)buffer);
+           if (writelen > 0)
             {
-              /* Write everything up to this point, ignore the carriage
+              nwritten = file_write(&g_syslog_dev.sl_file, buffer, writelen);
-               * return.
+              if (nwritten < 0)
-               *
-               * - buffer points to next byte to output.
-               * - endptr points to the carriage return.
-               */
-
-              writelen = (size_t)((uintptr_t)endptr - (uintptr_t)buffer);
-              if (writelen > 0)
                 {
-                  nwritten = file_write(&g_syslog_dev.sl_file, buffer, writelen);
+                  errcode = -nwritten;
-                  if (nwritten < 0)
+                  goto errout_with_sem;
-                    {
-                      errcode = -nwritten;
-                      goto errout_with_sem;
-                    }
                 }
-
-              /* Adjust pointers */
-
-              writelen++;         /* Skip the carriage return */
-              buffer += writelen; /* Points past the carriage return */
             }
-            break;
 
-          case '\n':
+          /* Ignore the carriage return, but for the linefeed, output
+           * both a carriage return and a linefeed.
+           */
+
+          if (*endptr == '\n')
             {
-              /* Write everything up to this point, then add a carriage
-               * return and linefeed;
-               *
-               * - buffer points to next byte to output.
-               * - endptr points to the new line.
-               */
-
-               writelen = (size_t)((uintptr_t)endptr - (uintptr_t)buffer);
-               if (writelen > 0)
-                {
-                  nwritten = file_write(&g_syslog_dev.sl_file, buffer, writelen);
-                  if (nwritten < 0)
-                    {
-                      errcode = -nwritten;
-                      goto errout_with_sem;
-                    }
-                }
-
               nwritten = file_write(&g_syslog_dev.sl_file, g_syscrlf, 2);
               if (nwritten < 0)
                 {
                   errcode = -nwritten;
                   goto errout_with_sem;
                 }
-
-              /* Adjust pointers */
-
-              writelen++;         /* Skip the line feed */
-              buffer += writelen; /* Points past the line feed */
             }
-            break;
 
-          default:
+          /* Adjust pointers */
-            break;
+
+           writelen++;         /* Skip the special character */
+           buffer += writelen; /* Points past the special character */
         }
     }
 
-  /* Write any data at the end of the buffer.
+  /* Write any unterminated data at the end of the buffer.
    *
    * - buffer points to next byte to output.
-   * - endptr points to the NULL terminator.
+   * - endptr points to the end of the buffer plus 1.
    */
 
   writelen = (size_t)((uintptr_t)endptr - (uintptr_t)buffer);

drivers/syslog/syslog_intbuffer.c

@@ -133,7 +133,7 @@ int syslog_remove_intbuffer(void)
 
   flags = enter_critical_section();
 
-  /* How much space is left in the inbuffer? */
+  /* How much space is left in the intbuffer? */
 
   inndx  = (uint32_t)g_syslog_intbuffer.si_inndx;
   outndx = (uint32_t)g_syslog_intbuffer.si_outndx;
@@ -211,7 +211,7 @@ int syslog_add_intbuffer(int ch)
 
   flags = enter_critical_section();
 
-  /* How much space is left in the inbuffer? */
+  /* How much space is left in the intbuffer? */
 
   inndx  = (uint32_t)g_syslog_intbuffer.si_inndx;
   outndx = (uint32_t)g_syslog_intbuffer.si_outndx;

drivers/syslog/syslog_stream.c

@@ -62,19 +62,24 @@ static void syslogstream_putc(FAR struct lib_outstream_s *this, int ch)
 #ifdef CONFIG_SYSLOG_BUFFER
   FAR struct lib_syslogstream_s *stream = (FAR struct lib_syslogstream_s *)this;
 
-  /* Add the incoming character to the buffer */
+  /* Discard carriage returns */
 
-  stream->buf[stream->nbuf] = ch;
+  if (ch != '\r')
-  stream->nbuf++;
-  this->nput++;
-
-  /* Is the buffer full?  Did we encounter a new line? */
-
-  if (stream->nbuf >= CONFIG_SYSLOG_BUFSIZE || ch == '\n')
     {
-      /* Yes.. then flush the buffer */
+      /* Add the incoming character to the buffer */
 
-      (void)this->flush(this);
+      stream->buf[stream->nbuf] = ch;
+      stream->nbuf++;
+      this->nput++;
+
+      /* Is the buffer full?  Did we encounter a new line? */
+
+      if (stream->nbuf >= CONFIG_SYSLOG_BUFSIZE || ch == '\n')
+        {
+          /* Yes.. then flush the buffer */
+
+          (void)this->flush(this);
+        }
     }
 #else
   int ret;
@@ -123,8 +128,8 @@ static int syslogstream_flush(FAR struct lib_outstream_s *this)
 
       do
         {
-          int status = syslog_write(stream->buf, stream->nbuf);
+          ssize_t nbytes = syslog_write(stream->buf, stream->nbuf);
-          if (status < 0)
+          if (nbytes < 0)
             {
               ret = -get_errno();
             }

drivers/syslog/vsyslog.c

@@ -108,21 +108,21 @@ int _vsyslog(int priority, FAR const IPTR char *fmt, FAR va_list *ap)
     {
       /* Use the SYSLOG emergency stream */
 
-      emergstream((FAR struct lib_outstream_s *)&stream);
+      emergstream(&stream.public);
     }
   else
     {
       /* Use the normal SYSLOG stream */
 
-      syslogstream((FAR struct lib_syslogstream_s *)&stream);
+      syslogstream(&stream);
     }
 
 #if defined(CONFIG_SYSLOG_TIMESTAMP)
   /* Pre-pend the message with the current time, if available */
 
-  (void)lib_sprintf((FAR struct lib_outstream_s *)&stream,
+  (void)lib_sprintf(&stream.public, "[%6d.%06d]",
-                    "[%6d.%06d]", ts.tv_sec, ts.tv_nsec/1000);
+                    ts.tv_sec, ts.tv_nsec/1000);
 #endif
 
-  return lib_vsprintf((FAR struct lib_outstream_s *)&stream, fmt, *ap);
+  return lib_vsprintf(&stream.public, fmt, *ap);
 }