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/* cap.c - Basic capability framework.
Copyright (C) 2007, 2008 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 General Public License as
published by the Free Software Foundation; either version 3 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
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see
<http://www.gnu.org/licenses/>. */
#include <assert.h>
#include <hurd/stddef.h>
#include <viengoos/messenger.h>
#include "cap.h"
#include "object.h"
#include "activity.h"
#include "thread.h"
const int cap_type_num_slots[] = { [vg_cap_void] = 0,
[vg_cap_page] = 0,
[vg_cap_rpage] = 0,
[vg_cap_cappage] = VG_CAPPAGE_SLOTS,
[vg_cap_rcappage] = VG_CAPPAGE_SLOTS,
[vg_cap_folio] = 0,
[vg_cap_activity] = 0,
[vg_cap_activity_control] = 0,
[vg_cap_thread] = VG_THREAD_SLOTS };
static struct vg_object *
cap_to_object_internal (struct activity *activity, struct vg_cap *cap,
bool hard)
{
if (cap->type == vg_cap_void)
return NULL;
/* XXX: If CAP does not grant write access, then we need to flatten
the discardable bit. */
struct vg_object *object;
if (hard)
{
object = object_find (activity, cap->oid, VG_CAP_POLICY_GET (*cap));
}
else
object = object_find_soft (activity, cap->oid, VG_CAP_POLICY_GET (*cap));
if (! object)
return NULL;
struct object_desc *desc = object_to_object_desc (object);
if (desc->version != cap->version)
{
/* Clear the capability to save the effort of looking up the
object in the future. */
cap->type = vg_cap_void;
return NULL;
}
/* If the capability is valid, then the cap type and the object type
must be compatible. */
assert (vg_cap_types_compatible (cap->type, desc->type));
return object;
}
struct vg_object *
vg_cap_to_object (struct activity *activity, struct vg_cap *cap)
{
return cap_to_object_internal (activity, cap, true);
}
struct vg_object *
cap_to_object_soft (struct activity *activity, struct vg_cap *cap)
{
return cap_to_object_internal (activity, cap, false);
}
void
cap_shootdown (struct activity *activity, struct vg_cap *root)
{
assert (activity);
/* XXX: A recursive function may not be the best idea here. We are
guaranteed, however, at most 63 nested calls. */
void doit (struct vg_cap *cap, int remaining)
{
int i;
struct vg_object *object;
remaining -= VG_CAP_GUARD_BITS (cap);
switch (cap->type)
{
case vg_cap_page:
case vg_cap_rpage:
if (remaining < PAGESIZE_LOG2)
return;
/* If the object is not in memory, then it can't be
mapped. */
object = object_find_soft (activity, cap->oid,
VG_OBJECT_POLICY (cap->discardable,
cap->priority));
if (! object)
return;
struct object_desc *desc = object_to_object_desc (object);
if (desc->version != cap->version)
{
/* Clear the capability to save the effort of looking up the
object in the future. */
cap->type = vg_cap_void;
return;
}
object_desc_unmap (desc);
return;
case vg_cap_cappage:
case vg_cap_rcappage:
if (remaining < VG_CAP_SUBPAGE_SIZE_LOG2 (cap) + PAGESIZE_LOG2)
return;
object = vg_cap_to_object (activity, cap);
if (! object)
return;
remaining -= VG_CAP_SUBPAGE_SIZE_LOG2 (cap);
for (i = 0; i < VG_CAP_SUBPAGE_SIZE (cap); i ++)
if (root->oid != object->caps[i].oid)
doit (&object->caps[i], remaining);
return;
case vg_cap_messenger:
case vg_cap_rmessenger:
if (remaining < VG_MESSENGER_SLOTS_LOG2 + PAGESIZE_LOG2)
return;
object = vg_cap_to_object (activity, cap);
if (! object)
return;
remaining -= VG_MESSENGER_SLOTS_LOG2;
for (i = 0; i < VG_MESSENGER_SLOTS_LOG2; i ++)
if (root->oid != object->caps[i].oid)
doit (&object->caps[i], remaining);
return;
case vg_cap_thread:
if (remaining < VG_THREAD_SLOTS_LOG2 + PAGESIZE_LOG2)
return;
object = vg_cap_to_object (activity, cap);
if (! object)
return;
remaining -= VG_THREAD_SLOTS_LOG2;
for (i = 0; i < VG_THREAD_SLOTS_LOG2; i ++)
if (root->oid != object->caps[i].oid)
doit (&object->caps[i],
remaining
+ (i == VG_THREAD_ASPACE_SLOT ? VG_THREAD_SLOTS_LOG2 : 0));
return;
case vg_cap_folio:
if (remaining < VG_FOLIO_OBJECTS_LOG2 + PAGESIZE_LOG2)
return;
object = vg_cap_to_object (activity, cap);
if (! object)
return;
struct vg_folio *folio = (struct vg_folio *) object;
struct object_desc *fdesc = object_to_object_desc (object);
vg_oid_t foid = fdesc->oid;
remaining -= VG_FOLIO_OBJECTS_LOG2;
for (i = 0; i < VG_FOLIO_OBJECTS; i ++)
if (vg_folio_object_type (folio, i) == vg_cap_page
|| vg_folio_object_type (folio, i) == vg_cap_rpage
|| vg_folio_object_type (folio, i) == vg_cap_cappage
|| vg_folio_object_type (folio, i) == vg_cap_rcappage)
{
struct vg_cap cap;
cap.version = folio_object_version (folio, i);
cap.type = vg_folio_object_type (folio, i);
cap.addr_trans = VG_CAP_ADDR_TRANS_VOID;
cap.oid = foid + 1 + i;
if (root->oid != cap.oid)
doit (&cap, remaining);
}
return;
default:
return;
}
}
doit (root, VG_ADDR_BITS);
}
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