1 files changed, 105 insertions, 0 deletions
diff --git a/libhurd-mm/mmap.c b/libhurd-mm/mmap.c
new file mode 100644
index 0000000..eb37e8c
--- /dev/null
+++ b/libhurd-mm/mmap.c
@@ -0,0 +1,105 @@
+/* mmap.c - mmap implementation.
+   Copyright (C) 2007 Free Software Foundation, Inc.
+   Written by Neal H. Walfield <neal@gnu.org>.
+
+   This file is part of the GNU Hurd.
+
+   The 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 2.1 of the License, or (at your option) any later version.
+
+   The 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 the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <hurd/stddef.h>
+#include <hurd/addr.h>
+#include <hurd/as.h>
+#include <hurd/storage.h>
+
+#include <sys/mman.h>
+#include <stdint.h>
+
+void *
+mmap (void *addr, size_t length, int protect, int flags,
+      int filedes, off_t offset)
+{
+  if (length == 0)
+    return MAP_FAILED;
+
+  if ((flags & ~(MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED)))
+    panic ("mmap called with invalid flags");
+  if (protect != (PROT_READ | PROT_WRITE))
+    panic ("mmap called with unsupported protection");
+
+  if ((flags & MAP_FIXED))
+    /* Interpret ADDR exactly.  */
+    {
+      if (((uintptr_t) addr & (PAGESIZE - 1)))
+	return MAP_FAILED;
+    }
+  else
+    {
+      /* Round the address down to a multiple of the pagesize.  */
+      addr = (void *) ((uintptr_t) addr & ~(PAGESIZE - 1));
+    }
+
+  /* Round length up.  */
+  length = (length + PAGESIZE - 1) & ~(PAGESIZE - 1);
+
+  bool alloced = false;
+  if (addr)
+    /* Caller wants a specific address range.  */
+    {
+      bool r = as_alloc_at (PTR_TO_ADDR (addr), length);
+      if (r)
+	alloced = true;
+      else
+	/* No room for this region.  */
+	{
+	  if (flags & MAP_FIXED)
+	    return MAP_FAILED;
+	}
+    }
+
+  if (! alloced)
+    {
+      addr_t region = as_alloc (PAGESIZE_LOG2, length / PAGESIZE, true);
+      if (ADDR_IS_VOID (region))
+	return MAP_FAILED;
+
+      addr = ADDR_TO_PTR (region);
+    }
+
+  /* Right now we allocate each page and its supporting data
+     structures immediately.  It may make more sense to setup a
+     pager.  */
+  /* XXX: Save the association between the storage that we allocate
+     and the addresses; we need to deallocate it on unmap!  */
+  uintptr_t page;
+  for (page = (uintptr_t) addr; page < (uintptr_t) addr + length;
+       page += PAGESIZE)
+    {
+      addr_t page_addr = PTR_TO_ADDR (page);
+      bool r = as_slot_ensure (page_addr);
+      if (! r)
+	panic ("Failed to ensure slot at 0x%x/%d",
+	       addr_prefix (page_addr), addr_depth (page_addr));
+
+      addr_t storage
+	= storage_alloc (ADDR_VOID,
+			 protect & PROT_WRITE ? cap_page : cap_rpage,
+			 STORAGE_UNKNOWN, page_addr);
+      if (ADDR_IS_VOID (storage))
+	panic ("Out of memory.");
+    }
+
+  return addr;
+}