diff -urN stdio-common/format.c stdio-common/format.c
--- stdio-common/format.c	1970-01-01 01:00:00.000000000 +0100
+++ stdio-common/format.c	2005-04-15 15:38:11.000000000 +0100
@@ -0,0 +1,53 @@
+#include "format.h"
+#include <malloc.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+
+static int setup = 0;
+static int format_log = 0;
+static void *heap_start = 0x00;
+static void *heap_end = 0x00;
+
+static void format_init(void)
+{
+	if (setup)
+		return;
+	else {
+		struct mallinfo malloc_info;
+		char *format_logging = NULL;
+
+		setup = 1;
+
+		format_logging = getenv("_FORMAT_CHECK");
+
+		if (!format_logging)
+			return;
+
+		if (format_logging)
+			format_log = atoi(format_logging);
+
+		malloc(0);
+		malloc_info = mallinfo();
+
+		heap_end = sbrk(0);
+		heap_start = heap_end - malloc_info.arena;
+	}
+}
+
+void format_check(const char *function, const char *format, int length)
+{
+	format_init();
+
+	if (!format_log)
+		return;
+	if ((void *)format > heap_start && (void *)format < heap_end) {
+		if (format_log == 6) kill(getpid(), SIGSEGV);
+		__libc_message(0, (!(format_log & 2) || strchr(format, 0x25)) ?
+			"info: format string is non-literal: %s(\"%p\");\n":
+			"warn: non-literal format string contains no specifiers: %s(\"%p\");\n",
+			function, format);
+	}
+	if ((format_log & 2) && length && strstr(format, "%s"))
+		__libc_message(0, "warn: format string contains an (percent)s with no length modifier: %s(\"%p\");\n", function, format);
+}
diff -urN stdio-common/format.h stdio-common/format.h
--- stdio-common/format.h	1970-01-01 01:00:00.000000000 +0100
+++ stdio-common/format.h	2005-04-15 15:38:11.000000000 +0100
@@ -0,0 +1,3 @@
+#include <stdarg.h>
+
+void format_check(const char *function, const char *format, int length);
diff -urN stdio-common/fprintf.c stdio-common/fprintf.c
--- stdio-common/fprintf.c	2004-03-19 00:21:39.000000000 +0000
+++ stdio-common/fprintf.c	2005-04-15 15:38:11.000000000 +0100
@@ -18,6 +18,7 @@
 
 #include <stdarg.h>
 #include <stdio.h>
+#include "format.h"
 
 
 /* Write formatted output to STREAM from the format string FORMAT.  */
@@ -28,6 +29,8 @@
   va_list arg;
   int done;
 
+  format_check(__FUNCTION__, format, 0);
+
   va_start (arg, format);
   done = vfprintf (stream, format, arg);
   va_end (arg);
diff -urN stdio-common/Makefile stdio-common/Makefile
--- stdio-common/Makefile	2004-08-10 19:01:29.000000000 +0100
+++ stdio-common/Makefile	2005-04-15 15:38:11.000000000 +0100
@@ -34,7 +34,7 @@
 	tmpfile tmpfile64 tmpnam tmpnam_r tempnam tempname		      \
 	getline getw putw						      \
 	remove rename							      \
-	flockfile ftrylockfile funlockfile
+	flockfile ftrylockfile funlockfile format
 
 install-others = $(inst_includedir)/bits/stdio_lim.h
 
diff -urN stdio-common/printf.c stdio-common/printf.c
--- stdio-common/printf.c	2004-03-19 00:21:39.000000000 +0000
+++ stdio-common/printf.c	2005-04-15 15:38:11.000000000 +0100
@@ -19,6 +19,7 @@
 
 #include <stdarg.h>
 #include <stdio.h>
+#include "format.h"
 
 #undef printf
 
@@ -30,6 +31,8 @@
   va_list arg;
   int done;
 
+  format_check(__FUNCTION__, format, 0);
+
   va_start (arg, format);
   done = vfprintf (stdout, format, arg);
   va_end (arg);
diff -urN stdio-common/snprintf.c stdio-common/snprintf.c
--- stdio-common/snprintf.c	2004-03-19 00:21:39.000000000 +0000
+++ stdio-common/snprintf.c	2005-04-15 15:38:11.000000000 +0100
@@ -31,6 +31,8 @@
   va_list arg;
   int done;
 
+  format_check(__FUNCTION__, format, 0);
+
   va_start (arg, format);
   done = __vsnprintf (s, maxlen, format, arg);
   va_end (arg);
diff -urN stdio-common/sprintf.c stdio-common/sprintf.c
--- stdio-common/sprintf.c	2004-03-19 00:21:39.000000000 +0000
+++ stdio-common/sprintf.c	2005-04-15 15:38:11.000000000 +0100
@@ -30,6 +30,8 @@
   va_list arg;
   int done;
 
+  format_check(__FUNCTION__, format, 0);
+
   va_start (arg, format);
   done = vsprintf (s, format, arg);
   va_end (arg);
diff -urN stdio-common/vfprintf.c stdio-common/vfprintf.c
--- stdio-common/vfprintf.c	2004-11-18 23:34:21.000000000 +0000
+++ stdio-common/vfprintf.c	2005-04-15 15:38:11.000000000 +0100
@@ -30,6 +30,7 @@
 #include "_itoa.h"
 #include <locale/localeinfo.h>
 #include <stdio.h>
+#include "format.h"
 
 /* This code is shared between the standard stdio implementation found
    in GNU C library and the libio implementation originally found in
@@ -1228,6 +1229,8 @@
   ORIENT;
 #endif
 
+  format_check(__FUNCTION__, format, 0);
+
   /* Sanity check of arguments.  */
   ARGCHECK (s, format);
 
diff -urN stdio-common/vfscanf.c stdio-common/vfscanf.c
--- stdio-common/vfscanf.c	2004-10-11 23:22:25.000000000 +0100
+++ stdio-common/vfscanf.c	2005-04-15 15:38:11.000000000 +0100
@@ -29,6 +29,7 @@
 #include <wctype.h>
 #include <bits/libc-lock.h>
 #include <locale/localeinfo.h>
+#include "format.h"
 
 #ifdef	__GNUC__
 # define HAVE_LONGLONG
@@ -281,6 +282,8 @@
   ORIENT;
 #endif
 
+  format_check(__FUNCTION__, format, 1);
+
   ARGCHECK (s, format);
 
  {
diff -urN stdio-common/vprintf.c stdio-common/vprintf.c
--- stdio-common/vprintf.c	2001-07-06 05:55:41.000000000 +0100
+++ stdio-common/vprintf.c	2005-04-15 15:38:11.000000000 +0100
@@ -29,5 +29,7 @@
      const char *format;
      __gnuc_va_list arg;
 {
+  format_check(__FUNCTION__, format, 0);
+
   return vfprintf (stdout, format, arg);
 }