On Tue, Jul 13, 2010 at 5:24 PM, Don Maghrak <[email protected]> wrote:
>
> Is there a way to have configure ensure that mincore is only
> used at linux 2.6.21 or later?
> For now we are undefining HAVE_MINCORE in our builds but that makes
> deployment on multiple systems difficult.
A runtime check is probably too expensive. A compile time check fails
if you compile on a new kernel and deploy on an old kernel.
The attached patch should allow you to turn off HAVE_MINCORE via a
configure time flag.
-Arun
diff --git a/configure.in b/configure.in
index 8e2d138..ae68370 100644
--- a/configure.in
+++ b/configure.in
@@ -76,7 +76,7 @@ dnl Checks for library functions.
AC_FUNC_MEMCMP
AC_TYPE_SIGNAL
AC_CHECK_FUNCS(dl_iterate_phdr dl_phdr_removals_counter dlmodinfo getunwind \
- ttrace mincore)
+ ttrace)
is_gcc_m64() {
if test `echo $CFLAGS | grep "\-m64" -c` -eq 1 ; then echo ppc64;
else
@@ -173,7 +173,16 @@ AC_ARG_ENABLE(conservative_checks,
[ --enable-conservative-checks Validate all memory addresses before use],
[enable_conservative_checks=$enableval], [enable_conservative_checks=yes])
if test x$enable_conservative_checks = xyes; then
- CPPFLAGS="${CPPFLAGS} -DCONSERVATIVE_CHECKS"
+ AC_DEFINE(CONSERVATIVE_CHECKS, 1,
+ [Define to 1 if you want every memory access validated])
+fi
+
+AC_ARG_ENABLE(mincore,
+[ --enable-mincore Use mincore(2) for validating that memory is readable],
+[enable_mincore=$enableval], [])
+if test x$enable_mincore = xyes; then
+ AC_DEFINE(HAVE_MINCORE, 1,
+ [Define to 1 if you want to use mincore(2) for validation])
fi
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