Add thread safety to some environment accesses

The previous commit added a mutex specifically for protecting against
simultaneous accesses of the environment.  This commit changes the
normal getenv, putenv, and clearenv functions to use it, to avoid races.

This makes the code simpler in places where we've gotten burned and
added stuff to avoid races.  Other places where we haven't known we were
getting burned could have existed until now.  Now that comes
automatically, and we can remove the special cases we earlier stumbled
over.

getenv() returns a pointer to static memory, which can be overwritten at
any moment from another thread, or even another getenv from the same
thread.  This commit changes the accesses to be under control of a
mutex, and in the case of getenv, a mortalized copy is created so that
there is no possible race.

1 files changed, 0 insertions, 4 deletions

diff --git a/perl.c b/perl.c
index dc555fbc95..df672f5fdf 100644
--- a/perl.c
+++ b/perl.c
@@ -2283,10 +2283,6 @@ S_parse_body(pTHX_ char **env, XSINIT_t xsinit)
 #endif
 	(s = PerlEnv_getenv("PERL5OPT")))
     {
-        /* s points to static memory in getenv(), which may be overwritten at
-         * any time; use a mortal copy instead */
-	s = SvPVX(sv_2mortal(newSVpv(s, 0)));
-
 	while (isSPACE(*s))
 	    s++;
 	if (*s == '-' && *(s+1) == 'T') {