Chicken out: the hash randomisation is not on by default.

We switch over to the explicit mode: in other words, if
the $ENV{PERL_HASH_SEED} is on, we randomise.  Also, we
randomise only if PL_hash_seed_set is FALSE (this means
one can use PERL_HASH() before perl_run.)  Also, since
now PERL_HASH_SEED is okay even under -T, all should be fine.
(Ha!)

p4raw-id: //depot/perl@20135

1 files changed, 32 insertions, 0 deletions

diff --git a/util.c b/util.c
index 80af15519f..4f53a91417 100644
--- a/util.c
+++ b/util.c
@@ -4377,3 +4377,35 @@ Perl_seed(pTHX)
     return u;
 }
 
+UV
+Perl_get_seed(void)
+{
+     char *s = PerlEnv_getenv("PERL_HASH_SEED");
+     UV myseed = 0;
+
+     if (s)
+	  while (isSPACE(*s)) s++;
+     if (s && isDIGIT(*s))
+	  myseed = (UV)Atoul(s);
+     else
+#ifdef USE_HASH_SEED_EXPLICIT
+     if (s)
+#endif
+     {
+	  /* Compute a random seed */
+	  (void)seedDrand01((Rand_seed_t)seed());
+	  PL_srand_called = TRUE;
+	  myseed = (UV)(Drand01() * (NV)UV_MAX);
+#if RANDBITS < (UVSIZE * 8)
+	  /* Since there are not enough randbits to to reach all
+	   * the bits of a UV, the low bits might need extra
+	   * help.  Sum in another random number that will
+	   * fill in the low bits. */
+	  myseed +=
+	       (UV)(Drand01() * (NV)((1 << ((UVSIZE * 8 - RANDBITS))) - 1));
+#endif /* RANDBITS < (UVSIZE * 8) */
+     }
+     PL_hash_seed_set = TRUE;
+
+     return myseed;
+}