Files
xen/m4/python_fortify_noopt.m4
T
Ian Jackson 0013245473 tools: work around collision of -O0 and -D_FORTIFY_SOURCE
Some systems have python-config include -D_FORTIFY_SOURCE in the
CFLAGS.  But -D_FORTIFY_SOURCE does not (currently) work with -O0, and
-O0 is enabled in debug builds (since 1166ecf781).  As a result, on
those systems, debug builds fail.

Work around this problem as follows:
 * In configure, detect -D_FORTIFY_SOURCE in $(python-config --cflags)
 * If detected, set the new autoconf substitution and make variable
   PY_NOOPT_CFLAGS to -O1.
 * In tools/Rules.mk, where we add -O0, also add PY_NOOPT_CFLAGS
   (which will override the -O0 with -O1 if required).

Overriding the -O0 is better than disabling Fortify because the
latter might have an adverse security impact.  A user who wants to
disable optimisation completely even for Python and also disable
Fortify can set the environment variable
    EXTRA_CFLAGS_XEN_TOOLS='-U_FORTIFY_SOURCE -O0'

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Reported-by: Jan Beulich <JBeulich@suse.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
CC: Jan Beulich <JBeulich@suse.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Euan Harris <euan.harris@citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Tested-by: Don Slutz <dslutz@verizon.com>
2015-02-06 17:26:30 +00:00

32 lines
1004 B
Plaintext

dnl Defines PY_NOOPT_CFLAGS to either '' or -O1
dnl
dnl This is necessary because on some systems setup.py includes
dnl -D_FORTIFY_SOURCE but have a -D_FORTIFY_SOURCE which breaks
dnl with -O0. On those systems we arrange to use -O1 for debug
dnl builds instead.
AC_DEFUN([AX_CHECK_PYTHON_FORTIFY_NOOPT], [
AC_CACHE_CHECK([whether Python setup.py brokenly enables -D_FORTIFY_SOURCE],
[ax_cv_python_fortify],[
ax_cv_python_fortify=no
for arg in $($PYTHON-config --cflags); do
case "$arg" in
-D_FORTIFY_SOURCE=0) ax_cv_python_fortify=no ;;
-D_FORTIFY_SOURCE=*) ax_cv_python_fortify=yes ;;
-Wp,-D_FORTIFY_SOURCE=0) ax_cv_python_fortify=no ;;
-Wp,-D_FORTIFY_SOURCE=*) ax_cv_python_fortify=yes ;;
*) ;;
esac
done
])
AS_IF([test x$ax_cv_python_fortify = xyes],[
PY_NOOPT_CFLAGS=-O1
], [
PY_NOOPT_CFLAGS=''
])
AC_SUBST(PY_NOOPT_CFLAGS)
])