From ac55fab44d514355334e95dc18cbe5d3a3b2e0f6 Mon Sep 17 00:00:00 2001
From: Xiang Xiao <xiaoxiang@xiaomi.com>
Date: Mon, 27 Apr 2020 12:23:42 +0800
Subject: [PATCH] syslog: Check sc_flush in't NULL before invocation

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
---
 drivers/syslog/syslog_channel.c | 12 +-----------
 drivers/syslog/syslog_flush.c   |  8 ++++++--
 2 files changed, 7 insertions(+), 13 deletions(-)

diff --git a/drivers/syslog/syslog_channel.c b/drivers/syslog/syslog_channel.c
index c731aae951..2a8fd1c838 100644
--- a/drivers/syslog/syslog_channel.c
+++ b/drivers/syslog/syslog_channel.c
@@ -72,7 +72,6 @@
 #ifdef NEED_LOWPUTC
 static int syslog_default_putc(int ch);
 #endif
-static int syslog_default_flush(void);
 
 /****************************************************************************
  * Public Data
@@ -83,7 +82,6 @@ static const struct syslog_channel_s g_default_channel =
 {
   ramlog_putc,
   ramlog_putc,
-  syslog_default_flush
 };
 #elif defined(CONFIG_SYSLOG_RPMSG)
 static const struct syslog_channel_s g_default_channel =
@@ -98,14 +96,12 @@ static const struct syslog_channel_s g_default_channel =
 {
   up_putc,
   up_putc,
-  syslog_default_flush
 };
 #else
 static const struct syslog_channel_s g_default_channel =
 {
   syslog_default_putc,
   syslog_default_putc,
-  syslog_default_flush
 };
 #endif
 
@@ -132,11 +128,6 @@ static int syslog_default_putc(int ch)
 }
 #endif
 
-static int syslog_default_flush(void)
-{
-  return OK;
-}
-
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -163,8 +154,7 @@ int syslog_channel(FAR const struct syslog_channel_s *channel)
 
   if (channel != NULL)
     {
-      DEBUGASSERT(channel->sc_putc != NULL && channel->sc_force != NULL &&
-                  channel->sc_flush != NULL);
+      DEBUGASSERT(channel->sc_putc != NULL && channel->sc_force != NULL);
 
       g_syslog_channel = channel;
       return OK;
diff --git a/drivers/syslog/syslog_flush.c b/drivers/syslog/syslog_flush.c
index 24e6f49736..89e874f441 100644
--- a/drivers/syslog/syslog_flush.c
+++ b/drivers/syslog/syslog_flush.c
@@ -91,6 +91,10 @@ int syslog_flush(void)
 
   /* Then flush all of the buffered output to the SYSLOG device */
 
-  DEBUGASSERT(g_syslog_channel->sc_flush != NULL);
-  return g_syslog_channel->sc_flush();
+  if (g_syslog_channel->sc_flush != NULL)
+    {
+      return g_syslog_channel->sc_flush();
+    }
+
+  return OK;
 }