1 files changed, 135 insertions, 0 deletions
diff --git a/libhurd-mm/madvise.c b/libhurd-mm/madvise.c
new file mode 100644
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+++ b/libhurd-mm/madvise.c
@@ -0,0 +1,135 @@
+/* madvise.c - madvise implementation.
+   Copyright (C) 2008 Free Software Foundation, Inc.
+   Written by Neal H. Walfield <neal@gnu.org>.
+
+   This file is part of the GNU Hurd.
+
+   GNU Hurd is free software: you can redistribute it and/or modify it
+   under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation, either version 3 of the
+   License, or (at your option) any later version.
+
+   GNU Hurd is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with GNU Hurd.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <hurd/stddef.h>
+#include <hurd/addr.h>
+#include <hurd/as.h>
+#include <hurd/storage.h>
+#include <hurd/anonymous.h>
+#include <hurd/map.h>
+
+#include <sys/mman.h>
+#include <stdint.h>
+
+int
+madvise (void *addr, size_t length, int advice)
+{
+  if (((uintptr_t) addr & (PAGESIZE - 1)) != 0)
+    return EINVAL;
+  if ((length & (PAGESIZE - 1)) != 0)
+    return EINVAL;
+
+  switch (advice)
+    {
+    case MADV_NORMAL:
+      advice = pager_advice_normal;
+      break;
+    case MADV_RANDOM:
+      advice = pager_advice_random;
+      break;
+    case MADV_SEQUENTIAL:
+      advice = pager_advice_sequential;
+      break;
+    case MADV_WILLNEED:
+      advice = pager_advice_willneed;
+      break;
+    case MADV_DONTNEED:
+      advice = pager_advice_dontneed;
+      break;
+    default:
+      return EINVAL;
+    }
+
+  uintptr_t start = (uintptr_t) addr;
+  uintptr_t end = start + length - 1;
+
+  debug (0, "(%p, %x (%p), %d)", addr, length, end, advice);
+
+  struct region region = { (uintptr_t) addr, length };
+
+  maps_lock_lock ();
+
+  /* Find any pager that overlaps within the designated region.  */
+  struct map *map = map_find (region);
+  if (! map)
+    /* There are none.  We're done.  */
+    {
+      maps_lock_unlock ();
+      return 0;
+    }
+
+  /* There may be pagers that come lexically before as well as after
+     PAGER.  We start with PAGER and scan forward and then do the same
+     but scan backwards.  */
+  struct map *prev = hurd_btree_map_prev (map);
+
+  int dir;
+  for (dir = 0; dir < 2; dir ++, map = prev)
+    for (;
+	 map;
+	 map = (dir == 0 ? hurd_btree_map_next (map)
+		: hurd_btree_map_prev (map)))
+      {
+	uintptr_t map_start = map->region.start;
+	uintptr_t map_end = map_start + map->region.length - 1;
+
+	debug (5, "(%x-%x): considering %x-%x",
+	       start, end, map_start, map_end);
+
+	if (map_start > end || map_end < start)
+	  break;
+
+	/*
+	    map_start/map->offset                map_end
+                   /   \                           /  \
+                  v     v                         v    v
+	          +------------------------------------+
+	          |                                    | <- pager
+	          +------------------------------------+
+
+            ^     ^     ^                        ^     ^     ^
+	     \    |    /                          \    |   /
+                start                                 end
+
+	 */
+	uintptr_t s = map->offset;
+	uintptr_t l = map->region.length;
+	if (start > map_start)
+	  {
+	    s += start - map_start;
+	    l -= start - map_start;
+	  }
+	if (end < map_end)
+	  l -= map_end - end;
+
+	if (map->pager->advise)
+	  map->pager->advise (map->pager, s, l, advice);
+      }
+
+  maps_lock_unlock ();
+
+  return 0;
+}
+
+int
+posix_madvise (void *addr, size_t len, int advice)
+{
+  return madvise (addr, len, advice);
+}