Fix memory handling in strxfrm_l [BZ #16009]

[Modified from the original email by Siddhesh Poyarekar]

This patch solves bug #16009 by implementing an additional path in
strxfrm that does not depend on caching the weight and rule indices.

In detail the following changed:

* The old main loop was factored out of strxfrm_l into the function
do_xfrm_cached to be able to alternativly use the non-caching version
do_xfrm.

* strxfrm_l allocates a a fixed size array on the stack. If this is not
sufficiant to store the weight and rule indices, the non-caching path is
taken. As the cache size is not dependent on the input there can be no
problems with integer overflows or stack allocations greater than
__MAX_ALLOCA_CUTOFF. Note that malloc-ing is not possible because the
definition of strxfrm does not allow an oom errorhandling.

* The uncached path determines the weight and rule index for every char
and for every pass again.

* Passing all the locale data array by array resulted in very long
parameter lists, so I introduced a structure that holds them.

* Checking for zero src string has been moved a bit upwards, it is
before the locale data initialization now.

* To verify that the non-caching path works correct I added a test run
to localedata/sort-test.sh & localedata/xfrm-test.c where all strings
are patched up with spaces so that they are too large for the caching path.

1 files changed, 7 insertions, 0 deletions

diff --git a/localedata/sort-test.sh b/localedata/sort-test.sh
index dc23268a3a..1a102627b1 100644
--- a/localedata/sort-test.sh
+++ b/localedata/sort-test.sh
@@ -53,11 +53,18 @@ for l in $lang; do
    ${common_objpfx}localedata/xfrm-test $id < $cns.in \
    > ${common_objpfx}localedata/$cns.xout || here=1
   cmp -s $cns.in ${common_objpfx}localedata/$cns.xout || here=1
+  ${test_program_prefix_before_env} \
+   ${run_program_env} \
+   LC_ALL=$l ${test_program_prefix_after_env} \
+   ${common_objpfx}localedata/xfrm-test $id -nocache < $cns.in \
+   > ${common_objpfx}localedata/$cns.nocache.xout || here=1
+  cmp -s $cns.in ${common_objpfx}localedata/$cns.nocache.xout || here=1
   if test $here -eq 0; then
     echo "$l xfrm-test OK"
   else
     echo "$l xfrm-test FAIL"
     diff -u $cns.in ${common_objpfx}localedata/$cns.xout | sed 's/^/  /'
+    diff -u $cns.in ${common_objpfx}localedata/$cns.nocache.xout | sed 's/^/  /'
     status=1
   fi
 done