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* [newlib-cygwin] 2016-12-15 Giuseppe Musumeci <giuseppe.musumeci@broadcom.com>
@ 2016-12-15 17:14 Jeff Johnston
  0 siblings, 0 replies; only message in thread
From: Jeff Johnston @ 2016-12-15 17:14 UTC (permalink / raw)
  To: newlib-cvs

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=05272960abb77e1c53239683d4adc6077e5549ea

commit 05272960abb77e1c53239683d4adc6077e5549ea
Author: Jeff Johnston <jjohnstn@redhat.com>
Date:   Thu Dec 15 12:06:04 2016 -0500

    2016-12-15 Giuseppe Musumeci <giuseppe.musumeci@broadcom.com>
    
    __sinit initialises some common file descriptors as line buffered and
    relies on the first users of such FDs to call __smakebuf_r. If
    __smakebuf_r realises there's no space for a buffer (malloc returns
    NULL), it makes them unbuffered. However, while setting the __SNBF
    bit, it doesn't clear the __SLBF bit in the flags. Depending on the
    order in which functions check buffering flags in the FD, sometime
    they assume it's line buffered (e.g. __sfvwrite_r), trashing
    application memory that's not really been allocated to them.
    
    This patch solves the problem by clearing the unbuffered/line buffered
    flag when setting the line buffered/unbuffered flag.

Diff:
---
 newlib/libc/stdio/makebuf.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/newlib/libc/stdio/makebuf.c b/newlib/libc/stdio/makebuf.c
index c592578..ab20a08 100644
--- a/newlib/libc/stdio/makebuf.c
+++ b/newlib/libc/stdio/makebuf.c
@@ -55,7 +55,7 @@ _DEFUN(__smakebuf_r, (ptr, fp),
     {
       if (!(fp->_flags & __SSTR))
 	{
-	  fp->_flags |= __SNBF;
+	  fp->_flags = (fp->_flags & ~__SLBF) | __SNBF;
 	  fp->_bf._base = fp->_p = fp->_nbuf;
 	  fp->_bf._size = 1;
 	}
@@ -67,7 +67,7 @@ _DEFUN(__smakebuf_r, (ptr, fp),
       fp->_bf._base = fp->_p = (unsigned char *) p;
       fp->_bf._size = size;
       if (couldbetty && _isatty_r (ptr, fp->_file))
-	fp->_flags |= __SLBF;
+	fp->_flags = (fp->_flags & ~__SNBF) | __SLBF;
       fp->_flags |= flags;
     }
 }


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