buf_printf will now return false on errors, such as truncation

due to overflow.


git-svn-id: http://svn.openvpn.net/projects/openvpn/branches/BETA21/openvpn@3085 e7ae566f-a301-0410-adde-c780ea21d3b5

2 files changed, 8 insertions, 3 deletions

diff --git a/buffer.c b/buffer.c
index c90ff9f..498861e 100644
--- a/buffer.c
+++ b/buffer.c
@@ -182,9 +182,10 @@ buf_sub (struct buffer *buf, int size, bool prepend)
 /*
  * printf append to a buffer with overflow check
  */
-void
+bool
 buf_printf (struct buffer *buf, const char *format, ...)
 {
+  int ret = false;
   if (buf_defined (buf))
     {
       va_list arglist;
@@ -193,13 +194,17 @@ buf_printf (struct buffer *buf, const char *format, ...)
 
       if (cap > 0)
 	{
+	  int stat;
 	  va_start (arglist, format);
-	  vsnprintf ((char *)ptr, cap, format, arglist);
+	  stat = vsnprintf ((char *)ptr, cap, format, arglist);
 	  va_end (arglist);
 	  *(buf->data + buf->capacity - 1) = 0; /* windows vsnprintf needs this */
 	  buf->len += (int) strlen ((char *)ptr);
+	  if (stat >= 0 && stat < cap)
+	    ret = true;
 	}
     }
+  return ret;
 }
 
 /*
diff --git a/buffer.h b/buffer.h
index 8888869..7de3363 100644
--- a/buffer.h
+++ b/buffer.h
@@ -206,7 +206,7 @@ has_digit (const unsigned char* src)
 /*
  * printf append to a buffer with overflow check
  */
-void buf_printf (struct buffer *buf, const char *format, ...)
+bool buf_printf (struct buffer *buf, const char *format, ...)
 #ifdef __GNUC__
     __attribute__ ((format (printf, 2, 3)))
 #endif