Fix ftell bug after ungetc.

* libc/stdio/ftell.c (_ftell_r): Don't flush ungetc buffer on
ftell.
* libc/stdio64/ftello64.c (_ftello64_r): Likewise.
* libc/stdio/fflush.c (_fflush_r): Clear unget buffer when
repositioning underlying fd offset.
-------------------------------------------------------------------

2 files changed, 8 insertions, 3 deletions

diff --git a/newlib/libc/stdio/fflush.c b/newlib/libc/stdio/fflush.c
index 24bd6c10e..33e2e7b26 100644
--- a/newlib/libc/stdio/fflush.c
+++ b/newlib/libc/stdio/fflush.c
@@ -164,6 +164,8 @@ _DEFUN(_fflush_r, (ptr, fp),
 	      fp->_p = fp->_bf._base;
 	      if (fp->_flags & __SOFF)
 		fp->_offset = curoff;
+	      if (HASUB (fp))
+		FREEUB (ptr, fp);
 	    }
 	  else
 	    {
diff --git a/newlib/libc/stdio/ftell.c b/newlib/libc/stdio/ftell.c
index 2aa10b2c7..816cafa76 100644
--- a/newlib/libc/stdio/ftell.c
+++ b/newlib/libc/stdio/ftell.c
@@ -118,9 +118,12 @@ _DEFUN(_ftell_r, (ptr, fp),
       return -1L;
     }
 
-  /* Find offset of underlying I/O object, then
-     adjust for buffered bytes.  */
-  _fflush_r (ptr, fp);           /* may adjust seek offset on append stream */
+  /* Find offset of underlying I/O object, then adjust for buffered
+     bytes.  Flush a write stream, since the offset may be altered if
+     the stream is appending.  Do not flush a read stream, since we
+     must not lose the ungetc buffer.  */
+  if (fp->_flags & __SWR)
+    _fflush_r (ptr, fp);
   if (fp->_flags & __SOFF)
     pos = fp->_offset;
   else