Specialize mmap_heap_malloc on OS X to pass MAP_FIXED always.

This conditional is ugly; perhaps it ought to be refactored.  However,
after the change to the configuration script to add the linker option
reserving low address space, this is necessary for anything to work at
all on OS X for the moment.

diff --git a/v7/src/microcode/ux.c b/v7/src/microcode/ux.c
index 25fb1378084107b019f8e4a29e358e29ec65a6a4..05b8d94e5a3812ead85241cc44a8d0a5fe2bc658 100644 (file)
--- a/v7/src/microcode/ux.c
+++ b/v7/src/microcode/ux.c
@@ -1,6 +1,6 @@
 /* -*-C-*-
 
-$Id: ux.c,v 1.30 2007/01/05 21:19:25 cph Exp $
+$Id: ux.c,v 1.31 2007/01/22 07:47:39 riastradh Exp $
 
 Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
     1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
@@ -708,6 +708,14 @@ mmap_heap_malloc (unsigned long requested_length)
     unsigned long ps = (UX_getpagesize ());
     request = (((requested_length + (ps - 1)) / ps) * ps);
   }
+#ifdef __APPLE__
+  /* On OS X, we reserved the __PAGEZERO segment up to 0x4000000 by a */
+  /* magic linker command, but it works only if we request MAP_FIXED. */
+  /* (The third argument to `mmap_heap_malloc_1' specifies this.)     */
+  /* Since OS X does no address space randomization and has no /proc/ */
+  /* directory, there's no need to try `find_suitable_address'.       */
+  result = (mmap_heap_malloc_1 (min_result, request, true));
+#else
   switch (find_suitable_address (request,
                                 min_result,
                                 max_result,
@@ -725,6 +733,7 @@ mmap_heap_malloc (unsigned long requested_length)
       result = (mmap_heap_malloc_1 (min_result, request, false));
       break;
     }
+#endif
   if (result != 0)
     {
       if ((((unsigned long) result) >= min_result)