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/* Mark an rpc to be interrupted when a port dies
Copyright (C) 1995 Free Software Foundation, Inc.
Written by Miles Bader <miles@gnu.ai.mit.edu>
This program 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.
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
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., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "ports.h"
/* Arrange for hurd_cancel to be called on RPC's thread if OBJECT gets notified
that any of the things in COND have happened to PORT. RPC should be an
rpc on OBJECT. */
error_t
ports_interrupt_rpc_on_notification (void *object,
struct rpc_info *rpc,
mach_port_t port, mach_msg_id_t what)
{
int req_notify;
struct ports_notify *pn;
struct rpc_notify *new_req, *req;
struct port_info *pi = object;
mutex_lock (&_ports_lock);
new_req = _ports_free_rpc_notifies;
if (new_req)
_ports_free_rpc_notifies = new_req->next;
else
/* No free notify structs, allocate one; it's expected that 99% of the
time we'll add a new structure, so we malloc while we don't have the
lock, and free it if we're wrong. */
{
mutex_unlock (&_ports_lock); /* Don't hold the lock during malloc. */
new_req = malloc (sizeof (struct rpc_notify));
if (! new_req)
return ENOMEM;
mutex_lock (&_ports_lock);
}
/* Find any existing entry for PORT/WHAT. */
for (pn = _ports_notifications; pn; pn = pn->next)
if (pn->port == port && pn->what == what)
break;
if (! pn)
/* A notification on a new port. */
{
pn = _ports_free_ports_notifies;
if (pn)
_ports_free_ports_notifies = pn->next;
else
{
pn = malloc (sizeof (struct ports_notify));
if (! pn)
/* sigh. Free what we've alloced and return. */
{
new_req->next = _ports_free_rpc_notifies;
_ports_free_rpc_notifies = new_req;
mutex_unlock (&_ports_lock);
return ENOMEM;
}
}
pn->reqs = 0;
pn->port = port;
pn->what = what;
pn->pending = 0;
mutex_init (&pn->lock);
pn->next = _ports_notifications;
pn->prevp = &_ports_notifications;
_ports_notifications->prevp = &pn->next;
_ports_notifications = pn;
}
for (req = rpc->notifies; req; req = req->next)
if (req->notify == pn)
break;
if (req)
free (new_req);
else
{
req = new_req;
req->rpc = rpc;
req->notify = pn;
req->pending = 0;
req->next_req = pn->reqs;
req->prev_req_p = &pn->reqs;
pn->reqs->prev_req_p = &req->next_req;
pn->reqs = req;
req->next = rpc->notifies;
rpc->notifies = req;
}
/* Make sure that this request results in an interrupt. */
req->pending++;
/* Find out whether we should request a new notification (after we release
_PORTS_LOCK) -- PN may be new, or left over after a previous
notification (in which case our new request is likely to trigger an
immediate notification). */
req_notify = !pn->pending;
if (req_notify)
mutex_lock (&pn->lock);
mutex_unlock (&_ports_lock);
if (req_notify)
{
mach_port_t old;
error_t err =
mach_port_request_notification (mach_task_self (), port,
what, 1, pi->port_right,
MACH_MSG_TYPE_MAKE_SEND_ONCE, &old);
if (! err && old != MACH_PORT_NULL)
mach_port_deallocate (mach_task_self (), old);
pn->pending = 1;
mutex_unlock (&pn->lock);
return err;
}
else
return 0;
}
/* Arrange for hurd_cancel to be called on the current thread, which should
be an rpc on OBJECT, if PORT gets notified with the condition WHAT. */
error_t
ports_interrupt_self_on_notification (void *object,
mach_port_t port, mach_msg_id_t what)
{
struct rpc_info *rpc;
struct port_info *pi = object;
thread_t thread = hurd_thread_self ();
mutex_lock (&_ports_lock);
for (rpc = pi->current_rpcs; rpc; rpc = rpc->next)
if (rpc->thread == thread)
break;
mutex_unlock (&_ports_lock);
if (rpc)
/* We don't have to worry about RPC going away after we dropped the lock
because we're that thread, and we're still here. */
return ports_interrupt_rpc_on_notification (object, rpc, port, what);
else
/* This thread isn't in an rpc! */
return EIEIO;
}
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