Fix commit d088a062

	* vm/memory_object_proxy.c: New file.

1 files changed, 200 insertions, 0 deletions

diff --git a/vm/memory_object_proxy.c b/vm/memory_object_proxy.c
new file mode 100644
index 0000000..4d81a68
--- /dev/null
+++ b/vm/memory_object_proxy.c
@@ -0,0 +1,200 @@
+/* memory_object_proxy.c - Proxy memory objects for Mach.
+   Copyright (C) 2005 Free Software Foundation, Inc.
+   Written by Marcus Brinkmann.
+
+   This file is part of GNU Mach.
+
+   GNU Mach is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   GNU Mach 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
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA. */
+
+/* A proxy memory object is a kernel port that can be used like a real
+   memory object in a vm_map call, except that the current and maximum
+   protection are restricted to the proxy object's maximum protection
+   at the time the mapping is established.  The kernel port will hold
+   a reference to the real memory object for the life time of the
+   proxy object.
+
+   Note that we don't need to do any reference counting on the proxy
+   object.  Our caller will hold a reference to the proxy object when
+   looking it up, and is expected to acquire its own reference to the
+   real memory object if needed before releasing the reference to the
+   proxy object.
+
+   The user provided real memory object and the maximum protection are
+   not checked for validity.  The maximum protection is only used as a
+   mask, and the memory object is validated at the time the mapping is
+   established.  */
+
+#include <mach/port.h>
+#include <mach/kern_return.h>
+#include <mach/notify.h>
+#include <mach/vm_prot.h>
+#include <kern/zalloc.h>
+#include <kern/mach_param.h>
+#include <ipc/ipc_port.h>
+#include <ipc/ipc_space.h>
+
+/* The zone which holds our proxy memory objects.  */
+static zone_t memory_object_proxy_zone;
+
+struct memory_object_proxy
+{
+  struct ipc_port *port;
+
+  ipc_port_t object;
+  vm_prot_t max_protection;
+};
+typedef struct memory_object_proxy *memory_object_proxy_t;
+
+
+void
+memory_object_proxy_init (void)
+{
+  /* For limit, see PORT_MAX.  */
+  memory_object_proxy_zone = zinit (sizeof (struct memory_object_proxy), 0,
+				    (TASK_MAX * 3 + THREAD_MAX)
+				    * sizeof (struct memory_object_proxy),
+				    256 * sizeof (struct memory_object_proxy),
+				    ZONE_EXHAUSTIBLE,
+				    "proxy memory object zone");
+}
+  
+/* Lookup a proxy memory object by its port.  */
+static memory_object_proxy_t
+memory_object_proxy_port_lookup (ipc_port_t port)
+{
+  memory_object_proxy_t proxy;
+
+  if (!IP_VALID(port))
+    return 0;
+
+  ip_lock (port);
+  if (ip_active (port) && (ip_kotype (port) == IKOT_PAGER_PROXY))
+    proxy = (memory_object_proxy_t) port->ip_kobject;
+  else
+    proxy = 0;
+  ip_unlock (port);
+  return proxy;
+}
+
+
+/* Process a no-sender notification for the proxy memory object
+   port.  */
+boolean_t
+memory_object_proxy_notify (mach_msg_header_t *msg)
+{
+  if (msg->msgh_id == MACH_NOTIFY_NO_SENDERS)
+    {
+      memory_object_proxy_t proxy;
+      mach_no_senders_notification_t *ns;
+
+      ns = (mach_no_senders_notification_t *) msg;
+      proxy = memory_object_proxy_port_lookup
+	((ipc_port_t) ns->not_header.msgh_remote_port);
+      assert (proxy);
+
+      ipc_port_release_send (proxy->object);
+      return TRUE;
+    }
+
+  printf ("memory_object_proxy_notify: strange notification %d\n",
+	  msg->msgh_id);
+  return FALSE;
+}
+
+
+/* Create a new proxy memory object from [START;START+LEN) in the
+   given OBJECT at OFFSET in the new object with the maximum
+   protection MAX_PROTECTION and return it in *PORT.  */
+kern_return_t
+memory_object_create_proxy (ipc_space_t space, vm_prot_t max_protection,
+			    ipc_port_t *object, natural_t object_count,
+			    vm_offset_t *offset, natural_t offset_count,
+			    vm_offset_t *start, natural_t start_count,
+			    vm_offset_t *len, natural_t len_count,
+			    ipc_port_t *port)
+{
+  kern_return_t kr;
+  memory_object_proxy_t proxy;
+  ipc_port_t notify;
+
+  if (space == IS_NULL)
+    return KERN_INVALID_TASK;
+
+  if (offset_count != object_count || start_count != object_count
+      || len_count != object_count)
+    return KERN_INVALID_ARGUMENT;
+
+  /* FIXME: Support more than one memory object.  */
+  if (object_count != 1)
+    return KERN_INVALID_ARGUMENT;
+
+  if (!IP_VALID(object[0]))
+    return KERN_INVALID_NAME;
+
+  /* FIXME: Support a different offset from 0.  */
+  if (offset[0] != 0)
+    return KERN_INVALID_ARGUMENT;
+
+  /* FIXME: Support a different range from total.  */
+  if (start[0] != 0 || len[0] != (vm_offset_t) ~0)
+    return KERN_INVALID_ARGUMENT;
+
+  proxy = (memory_object_proxy_t) zalloc (memory_object_proxy_zone);
+
+  /* Allocate port, keeping a reference for it.  */
+  proxy->port = ipc_port_alloc_kernel ();
+  if (proxy->port == IP_NULL)
+    {
+      zfree (memory_object_proxy_zone, (vm_offset_t) proxy);
+      return KERN_RESOURCE_SHORTAGE;
+    }
+  /* Associate the port with the proxy memory object.  */
+  ipc_kobject_set (proxy->port, (ipc_kobject_t) proxy, IKOT_PAGER_PROXY);
+
+  /* Request no-senders notifications on the port.  */
+  notify = ipc_port_make_sonce (proxy->port);
+  ip_lock (proxy->port);
+  ipc_port_nsrequest (proxy->port, 1, notify, &notify);
+  assert (notify == IP_NULL);
+
+  proxy->object = ipc_port_copy_send (object[0]);
+  proxy->max_protection = max_protection;
+
+  *port = ipc_port_make_send (proxy->port);
+  return KERN_SUCCESS;
+}
+
+
+/* Lookup the real memory object and maximum protection for the proxy
+   memory object port PORT, for which the caller holds a reference.
+   *OBJECT is only guaranteed to be valid as long as the caller holds
+   the reference to PORT (unless the caller acquires its own reference
+   to it).  If PORT is not a proxy memory object, return
+   KERN_INVALID_ARGUMENT.  */
+kern_return_t
+memory_object_proxy_lookup (ipc_port_t port, ipc_port_t *object,
+			    vm_prot_t *max_protection)
+{
+  memory_object_proxy_t proxy;
+
+  proxy = memory_object_proxy_port_lookup (port);
+  if (!proxy)
+    return KERN_INVALID_ARGUMENT;
+
+   *object = proxy->object;
+   *max_protection = proxy->max_protection;
+
+  return KERN_SUCCESS;
+}