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Diffstat (limited to 'viengoos/cap.c')
| -rw-r--r-- | viengoos/cap.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/viengoos/cap.c b/viengoos/cap.c new file mode 100644 index 0000000..f1ea7bb --- /dev/null +++ b/viengoos/cap.c @@ -0,0 +1,166 @@ +/* cap.c - Basic capability framework. + 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 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 "cap.h" +#include "object.h" +#include "activity.h" + +const int cap_type_num_slots[] = { [cap_void] = 0, + [cap_page] = 0, + [cap_rpage] = 0, + [cap_cappage] = CAPPAGE_SLOTS, + [cap_rcappage] = CAPPAGE_SLOTS, + [cap_folio] = 0, + [cap_activity] = 0, + [cap_activity_control] = 0, + [cap_thread] = THREAD_SLOTS }; + +void +cap_set_object (struct cap *cap, + struct object *object, enum cap_type type) +{ + *cap = object_to_cap (object); + assert (cap->type == type); +} + +struct object * +cap_to_object (struct activity *activity, struct cap *cap) +{ + if (cap->type == cap_void) + return NULL; + + struct object *object = object_find (activity, cap->oid); + 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 = cap_void; + return NULL; + } + + /* If the capability is valid, then the types must match. */ + assert (cap->type == desc->type); + + return object; +} + +void +cap_shootdown (struct activity *activity, struct cap *cap) +{ + /* XXX: A recursive function may not be the best idea here. We are + guaranteed, however, at most 63 nested calls. */ + void doit (struct cap *cap, int remaining) + { + int i; + struct object *object; + + remaining -= CAP_GUARD_BITS (cap); + + switch (cap->type) + { + case cap_page: + case 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); + 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 = cap_void; + return; + } + +#ifndef _L4_TEST_ENVIRONMENT + l4_fpage_t fpage = l4_fpage ((l4_word_t) object, PAGESIZE); + fpage = l4_fpage_add_rights (fpage, L4_FPAGE_FULLY_ACCESSIBLE); + l4_unmap_fpage (fpage); +#endif + return; + + case cap_cappage: + case cap_rcappage: + if (remaining < CAP_SUBPAGE_SIZE_LOG2 (cap) + PAGESIZE_LOG2) + return; + + object = cap_to_object (activity, cap); + if (! object) + return; + + remaining -= CAP_SUBPAGE_SIZE_LOG2 (cap); + + for (i = 0; i < CAP_SUBPAGE_SIZE_LOG2 (cap); i ++) + doit (&object->caps[i], remaining); + + return; + + case cap_folio: + if (remaining < FOLIO_OBJECTS_LOG2 + PAGESIZE_LOG2) + return; + + object = cap_to_object (activity, cap); + if (! object) + return; + + struct folio *folio = (struct folio *) object; + struct object_desc *fdesc = object_to_object_desc (object); + oid_t foid = fdesc->oid; + + remaining -= FOLIO_OBJECTS_LOG2; + + for (i = 0; i < FOLIO_OBJECTS_LOG2; i ++) + if (folio->objects[i].type == cap_page + || folio->objects[i].type == cap_rpage + || folio->objects[i].type == cap_cappage + || folio->objects[i].type == cap_rcappage) + { + struct cap cap; + + cap.version = folio->objects[i].version; + cap.type = folio->objects[i].type; + cap.addr_trans = CAP_ADDR_TRANS_VOID; + cap.oid = foid + 1 + i; + + doit (&cap, remaining); + } + + return; + + default: + return; + } + } + + doit (cap, ADDR_BITS); +} |