[Bug libc/12685] New: fopen doesn't last byte of valid modes

["eblake at redhat dot com" <sourceware-bugzilla at sourceware dot org>]

http://sourceware.org/bugzilla/show_bug.cgi?id=12685

           Summary: fopen doesn't last byte of valid modes
           Product: glibc
           Version: 2.13
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
        AssignedTo: drepper.fsp@gmail.com
        ReportedBy: eblake@redhat.com


$ cat foo.c
#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>

int main (void)
{
  FILE *f = fopen ("/dev/null", "rb+cmxe");
  if (!f) exit (1);
  int fd = fileno (f);
  if (fd < 0) exit (2);
  int mode = fcntl (fd, F_GETFD);
  if (mode < 0) exit (3);
  return !(mode & FD_CLOEXEC);
}
$ ./foo; echo $?
1

Oops - an off-by-one error in fileops.c ended up ignoring 'e'.  The same goes
for any other valid byte that doesn't appear until mode[6].

diff --git i/libio/fileops.c w/libio/fileops.c
index 4698953..ee6ce13 100644
--- i/libio/fileops.c
+++ w/libio/fileops.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1993, 1995, 1997-2005, 2006, 2007, 2008, 2009
+/* Copyright (C) 1993, 1995, 1997-2005, 2006, 2007, 2008, 2009, 2011
    Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Written by Per Bothner <bothner@cygnus.com>.
@@ -290,7 +290,7 @@ _IO_new_file_fopen (fp, filename, mode, is32not64)
 #ifdef _LIBC
   last_recognized = mode;
 #endif
-  for (i = 1; i < 6; ++i)
+  for (i = 1; i < 7; ++i)
     {
       switch (*++mode)
     {

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