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/* cap-user.c - User side of the capability implementation.
Copyright (C) 2003 Free Software Foundation, Inc.
Written by Marcus Brinkmann <marcus@gnu.org>
This file is part of the GNU Hurd.
This program 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.
This program 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 this program; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#if HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdlib.h>
#include <pthread.h>
#include <assert.h>
#include <errno.h>
#include <stdint.h>
#include <l4/thread.h>
#include <hurd/cap.h>
#include "cap-intern.h"
/* This hash table maps server thread IDs to server connections. */
static struct hurd_ihash server_to_sconn
= HURD_IHASH_INITIALIZER (HURD_IHASH_NO_LOCP);
/* This lock protects SERVER_TO_SCONN. You can also lock server
connection objects while holding this lock. */
static pthread_mutex_t server_to_sconn_lock = PTHREAD_MUTEX_INITIALIZER;
/* Deallocate one reference for SCONN, which must be locked.
SERVER_TO_SCONN_LOCK is not locked. Afterwards, SCONN is unlocked
(if it still exists). */
void
_hurd_cap_sconn_dealloc (hurd_cap_sconn_t sconn)
{
assert (sconn->refs > 0);
sconn->refs--;
if (sconn->refs > 0)
{
pthread_mutex_unlock (&sconn->lock);
return;
}
/* We have to get SERVER_TO_SCONN_LOCK, but the locking order does
not allow us to do it directly. So we release SCONN
temporarily. */
sconn->refs = 1;
pthread_mutex_unlock (&sconn->lock);
pthread_mutex_lock (&server_to_sconn_lock);
pthread_mutex_lock (&sconn->lock);
assert (sconn->refs > 0);
sconn->refs--;
if (sconn->refs > 0)
{
pthread_mutex_unlock (&sconn->lock);
return;
}
/* Now we can remove the object. */
hurd_ihash_remove (&server_to_sconn, sconn->server_thread);
pthread_mutex_unlock (&server_to_sconn_lock);
/* Finally, we can destroy it. */
pthread_mutex_unlock (&sconn->lock);
pthread_mutex_destroy (&sconn->lock);
hurd_ihash_destroy (&sconn->id_to_cap);
if (sconn->server_task_info)
hurd_cap_deallocate (sconn->server_task_info);
free (sconn);
}
/* Remove the entry for the capability ID SCID from the server
connection SCONN. SCONN is locked. Afterwards, SCONN is
unlocked. */
void
_hurd_cap_sconn_remove (hurd_cap_sconn_t sconn, l4_word_t scid)
{
/* Remove the capability object pointer, which is now invalid. */
hurd_ihash_remove (&sconn->id_to_cap, scid);
/* FIXME: The following should be some low level RPC to deallocate
the capability on the server side. If it fails, then what can we
do at this point? */
hurd_cap_server_deallocate (sconn->server_thread, scid);
_hurd_cap_sconn_dealloc (sconn);
}
/* Enter a new send capability provided by the server SERVER_THREAD
(with the task ID reference SERVER_TASK_INFO) and the cap ID SCID.
SCONN is the server connection for SERVER_THREAD, if known. It
should be unlocked. If SCONN is NULL, then SERVER_TASK_INFO should
be the task info capability for the server SERVER_THREAD, otherwise
it must be HURD_CAP_NULL. Both, SCONN and SERVER_TASK_INFO, are
consumed if used. If successful, the locked capability is returned
with one (additional) reference in CAP. The server connection and
capability object are created if necessary. */
error_t
_hurd_cap_sconn_enter (hurd_cap_sconn_t sconn_provided,
hurd_task_info_t server_task_info,
l4_thread_id_t server_thread, uint32_t scid,
hurd_cap_t *cap)
{
hurd_cap_sconn_t sconn = sconn_provided;
int sconn_created = 0;
if (sconn)
assert (l4_is_thread_equal (sconn->server_thread, server_thread));
else
{
/* It might have become available by now. */
pthread_mutex_lock (&server_to_sconn_lock);
sconn = hurd_ihash_find (&server_to_sconn, server_thread);
if (sconn)
hurd_cap_deallocate (server_task_info);
else
{
error_t err;
sconn = malloc (sizeof (*sconn));
if (!sconn)
{
pthread_mutex_unlock (&server_to_sconn_lock);
hurd_cap_deallocate (server_task_info);
return errno;
}
err = pthread_mutex_init (&sconn->lock, NULL);
if (err)
{
free (sconn);
pthread_mutex_unlock (&server_to_sconn_lock);
hurd_cap_deallocate (server_task_info);
return errno;
}
hurd_ihash_init (&sconn->id_to_cap, HURD_IHASH_NO_LOCP);
sconn->server_thread = server_thread;
sconn->server_task_info = server_task_info;
sconn->refs = 0;
/* Enter the new server connection object. */
err = hurd_ihash_add (&server_to_sconn, server_thread, sconn);
if (err)
{
pthread_mutex_destroy (&sconn->lock);
hurd_ihash_destroy (&sconn->id_to_cap);
free (sconn);
pthread_mutex_unlock (&server_to_sconn_lock);
hurd_cap_deallocate (server_task_info);
return errno;
}
}
}
pthread_mutex_lock (&sconn->lock);
pthread_mutex_unlock (&server_to_sconn_lock);
(*cap) = hurd_ihash_find (&sconn->id_to_cap, scid);
if (!cap)
{
error_t err = hurd_slab_alloc (cap_space, cap);
if (err)
{
_hurd_cap_sconn_dealloc (sconn);
return err;
}
(*cap)->sconn = sconn;
(*cap)->scid = scid;
#if 0
(*cap)->dead_cb = NULL;
#endif
err = hurd_ihash_add (&sconn->id_to_cap, scid, *cap);
if (err)
{
_hurd_cap_sconn_dealloc (sconn);
hurd_slab_dealloc (cap_space, *cap);
return err;
}
}
pthread_mutex_lock (&(*cap)->lock);
(*cap)->srefs++;
/* We have to add a reference for the capability we have added,
unless we are consuming the reference that was provided. */
if (!sconn_provided)
sconn->refs++;
pthread_mutex_unlock (&sconn->lock);
return 0;
}
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