diff --git a/components/libc/armlibc/stubs.c b/components/libc/armlibc/stubs.c
index b74710e056..bd57ca4c54 100644
--- a/components/libc/armlibc/stubs.c
+++ b/components/libc/armlibc/stubs.c
@@ -13,7 +13,7 @@
  * Date           Author       Notes
  * 2012-11-23     Yihui        The first version
  * 2013-11-24     aozima       fixed _sys_read()/_sys_write() issues.
- * 2014-08-03     bernard      If using msh, use system() implementation 
+ * 2014-08-03     bernard      If using msh, use system() implementation
  *                             in msh.
  */
 
@@ -48,11 +48,11 @@ const char __stderr_name[] = "STDERR";
  */
 FILEHANDLE _sys_open(const char *name, int openmode)
 {
-#ifdef RT_USING_DFS    
+#ifdef RT_USING_DFS
     int fd;
     int mode = O_RDONLY;
 #endif
-    
+
     /* Register standard Input Output devices. */
     if (strcmp(name, __stdin_name) == 0)
         return (STDIN);
@@ -64,34 +64,34 @@ FILEHANDLE _sys_open(const char *name, int openmode)
 #ifndef RT_USING_DFS
     return -1;
 #else
-	/* Correct openmode from fopen to open */
-	if (openmode & OPEN_PLUS) 
-	{
-		if (openmode & OPEN_W) 
-		{
-			mode |= (O_RDWR | O_TRUNC | O_CREAT);
-		}
-		else if (openmode & OPEN_A) 
-		{
-			mode |= (O_RDWR | O_APPEND | O_CREAT);
-		}
-		else 
-			mode |= O_RDWR;				
-	}
-	else
-	{
-		if (openmode & OPEN_W) 
-		{
-			mode |= (O_WRONLY | O_TRUNC | O_CREAT);
-		}
-		else if (openmode & OPEN_A)
-		{					
+    /* Correct openmode from fopen to open */
+    if (openmode & OPEN_PLUS)
+    {
+        if (openmode & OPEN_W)
+        {
+            mode |= (O_RDWR | O_TRUNC | O_CREAT);
+        }
+        else if (openmode & OPEN_A)
+        {
+            mode |= (O_RDWR | O_APPEND | O_CREAT);
+        }
+        else
+            mode |= O_RDWR;
+    }
+    else
+    {
+        if (openmode & OPEN_W)
+        {
+            mode |= (O_WRONLY | O_TRUNC | O_CREAT);
+        }
+        else if (openmode & OPEN_A)
+        {
             mode |= (O_WRONLY | O_APPEND | O_CREAT);
-		}					
-	}
+        }
+    }
 
     fd = open(name, mode, 0);
-    if(fd < 0)
+    if (fd < 0)
         return -1;
     else
         return fd + STDERR + 1;
@@ -121,10 +121,10 @@ int _sys_close(FILEHANDLE fh)
  */
 int _sys_read(FILEHANDLE fh, unsigned char *buf, unsigned len, int mode)
 {
-#ifdef RT_USING_DFS    
+#ifdef RT_USING_DFS
     int size;
 #endif
-    
+
     if (fh == STDIN)
     {
         /* TODO */
@@ -138,7 +138,7 @@ int _sys_read(FILEHANDLE fh, unsigned char *buf, unsigned len, int mode)
     return 0;
 #else
     size = read(fh - STDERR - 1, buf, len);
-    if(size >= 0)
+    if (size >= 0)
         return len - size;
     else
         return -1;
@@ -159,7 +159,7 @@ int _sys_write(FILEHANDLE fh, const unsigned char *buf, unsigned len, int mode)
 #ifdef RT_USING_DFS
     int size;
 #endif
-    
+
     if ((fh == STDOUT) || (fh == STDERR))
     {
 #ifndef RT_USING_CONSOLE
@@ -170,18 +170,18 @@ int _sys_write(FILEHANDLE fh, const unsigned char *buf, unsigned len, int mode)
         console_device = rt_console_get_device();
         if (console_device != 0) rt_device_write(console_device, 0, buf, len);
 
-		return 0;
+        return 0;
 #endif
     }
 
-    if(fh == STDIN)
+    if (fh == STDIN)
         return -1;
 
 #ifndef RT_USING_DFS
     return 0;
 #else
     size = write(fh - STDERR - 1, buf, len);
-    if(size >= 0)
+    if (size >= 0)
         return len - size;
     else
         return -1;
@@ -270,6 +270,6 @@ int remove(const char *filename)
 int system(const char *string)
 {
     RT_ASSERT(0);
-    for(;;);
+    for (;;);
 }
 #endif