Perl_init_tm: Use mutex to avoid race.

This locks around localtime (and localtime_r which this call may be
translated into) which are sensitive to locale and environment changes
in their execution.

1 files changed, 2 insertions, 0 deletions

diff --git a/util.c b/util.c
index e968aceca4..3b910965aa 100644
--- a/util.c
+++ b/util.c
@@ -3637,9 +3637,11 @@ Perl_init_tm(pTHX_ struct tm *ptm)	/* see mktime, strftime and asctime */
     PERL_UNUSED_CONTEXT;
     PERL_ARGS_ASSERT_INIT_TM;
     (void)time(&now);
+    ENV_LOCALE_READ_LOCK;
     my_tm = localtime(&now);
     if (my_tm)
         Copy(my_tm, ptm, 1, struct tm);
+    ENV_LOCALE_READ_UNLOCK;
 #else
     PERL_UNUSED_CONTEXT;
     PERL_ARGS_ASSERT_INIT_TM;