patches/glibc/2.6.1/160-use_short_for_fnstsw.patch
author "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
Mon Feb 21 23:39:46 2011 +0100 (2011-02-21)
changeset 2312 8b9938edd3d8
parent 607 aaf7ae5cb11a
permissions -rw-r--r--
libc/glibc: add fortify option

By default, recent versions of glibc and eglibc will build some
functions that take format strings (eg. printf, syslog...) with
run-time checks against some format string attacks. This is
called a fortified build.

Unfortunately, this fails somehow while building the instrumented
version of syslog, with some kind of circular dependency...

Disable fortified builds by default, and hide the enabling option
behind EXPERIMENTAL for daring users...

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>
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Original patch from H.J. Lu, as reported there:
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http://www.nabble.com/PATCH:-Use-short-for-fnstsw-td14775171.html
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fnstsw stores 16bit into %ax. The upper 16bit of %eax is unchanged.
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The new assembler (binutils-2.18.50.0.4 and up) will disallow "fnstsw %eax".
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diff -dur glibc-2.6.1.orig/sysdeps/i386/fpu/ftestexcept.c glibc-2.6.1/sysdeps/i386/fpu/ftestexcept.c
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--- glibc-2.6.1.orig/sysdeps/i386/fpu/ftestexcept.c	2004-03-05 11:14:48.000000000 +0100
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+++ glibc-2.6.1/sysdeps/i386/fpu/ftestexcept.c	2008-06-24 10:56:14.000000000 +0200
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@@ -26,7 +26,7 @@
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 int
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 fetestexcept (int excepts)
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 {
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-  int temp;
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+  short temp;
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   int xtemp = 0;
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   /* Get current exceptions.  */