Add back an #ifndef MAP_INHERIT_ZERO chunk to support the old getpid()

mechanism, to aid in portability to other systems as requested.
ok matthew

1 files changed, 13 insertions, 1 deletions

diff --git a/src/lib/libc/crypt/arc4random.c b/src/lib/libc/crypt/arc4random.c
index a306c6d8ab..ee47b2df34 100644
--- a/src/lib/libc/crypt/arc4random.c
+++ b/src/lib/libc/crypt/arc4random.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: arc4random.c,v 1.37 2014/06/25 04:22:08 deraadt Exp $ */
+/*      $OpenBSD: arc4random.c,v 1.38 2014/06/26 19:23:15 deraadt Exp $ */
 
 /*
  * Copyright (c) 1996, David Mazieres <dm@uun.org>
@@ -74,8 +74,10 @@ _rs_init(u_char *buf, size_t n)
                 if ((rs = mmap(NULL, sizeof(*rs), PROT_READ|PROT_WRITE,
                     MAP_ANON|MAP_PRIVATE, -1, 0)) == MAP_FAILED)
                         abort();
+#ifdef MAP_INHERIT_ZERO
                 if (minherit(rs, sizeof(*rs), MAP_INHERIT_ZERO) == -1)
                         abort();
+#endif
         }
         if (rsx == NULL) {
                 if ((rsx = mmap(NULL, sizeof(*rsx), PROT_READ|PROT_WRITE,
@@ -111,6 +113,16 @@ _rs_stir(void)
 static inline void
 _rs_stir_if_needed(size_t len)
 {
+#ifndef MAP_INHERIT_ZERO
+        static pid_t _rs_pid = 0;
+        pid_t pid = getpid();
+
+        /* If a system lacks MAP_INHERIT_ZERO, resort to getpid() */
+        if (_rs_pid == 0 || _rs_pid != pid) {
+                _rs_pid = pid;
+                rs->rs_count = 0;
+        }
+#endif
         if (!rs || rs->rs_count <= len)
                 _rs_stir();
         if (rs->rs_count <= len)