Use PRINTF_FORTIFY instead of _IO_FLAGS2_FORTIFY (bug 11319)

The _chk variants of all of the printf functions become much simpler.
This is the last thing that we needed _IO_acquire_lock_clear_flags2
for, so it can go as well.  I took the opportunity to make the headers
included and the names of all local variables consistent across all the
affected files.

Since we ultimately want to get rid of __no_long_double as well, it
must be possible to get all of the nontrivial effects of the _chk
functions by calling the _internal functions with appropriate flags.
For most of the __(v)xprintf_chk functions, this is covered by
PRINTF_FORTIFY plus some up-front argument checks that can be
duplicated.  However, __(v)sprintf_chk installs a custom jump table so
that it can crash instead of overflowing the output buffer.  This
functionality is moved to __vsprintf_internal, which now has a
'maxlen' argument like __vsnprintf_internal; to get the unsafe
behavior of ordinary (v)sprintf, pass -1 for that argument.

obstack_printf_chk and obstack_vprintf_chk are no longer in the same
file.

As a side-effect of the unification of both fortified and non-fortified
vdprintf initialization, this patch fixes bug 11319 for __dprintf_chk
and __vdprintf_chk, which was previously fixed only for dprintf and
vdprintf by the commit

commit 7ca890b88e6ab7624afb1742a9fffb37ad5b3fc3
Author: Ulrich Drepper <drepper@redhat.com>
Date:   Wed Feb 24 16:07:57 2010 -0800

    Fix reporting of I/O errors in *dprintf functions.

This patch adds a test case to avoid regressions.

Tested for powerpc and powerpc64le.

1 files changed, 14 insertions, 10 deletions

diff --git a/debug/snprintf_chk.c b/debug/snprintf_chk.c
index cddba37109..984b5e8932 100644
--- a/debug/snprintf_chk.c
+++ b/debug/snprintf_chk.c
@@ -15,25 +15,29 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <libioP.h>
 #include <stdarg.h>
-#include <stdio.h>
+#include <libio/libioP.h>
 
 
 /* Write formatted output into S, according to the format
    string FORMAT, writing no more than MAXLEN characters.  */
-/* VARARGS5 */
 int
-___snprintf_chk (char *s, size_t maxlen, int flags, size_t slen,
+___snprintf_chk (char *s, size_t maxlen, int flag, size_t slen,
 		 const char *format, ...)
 {
-  va_list arg;
-  int done;
+  if (__glibc_unlikely (slen < maxlen))
+    __chk_fail ();
 
-  va_start (arg, format);
-  done = __vsnprintf_chk (s, maxlen, flags, slen, format, arg);
-  va_end (arg);
+  /* For flag > 0 (i.e. __USE_FORTIFY_LEVEL > 1) request that %n
+     can only come from read-only format strings.  */
+  unsigned int mode = (flag > 0) ? PRINTF_FORTIFY : 0;
+  va_list ap;
+  int ret;
 
-  return done;
+  va_start (ap, format);
+  ret = __vsnprintf_internal (s, maxlen, format, ap, mode);
+  va_end (ap);
+
+  return ret;
 }
 ldbl_strong_alias (___snprintf_chk, __snprintf_chk)