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/* Transfer the receive right from one port structure to another
Copyright (C) 1996 Free Software Foundation, Inc.
Written by Michael I. Bushnell, p/BSG.
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 2, 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, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA. */
#include "ports.h"
#include <hurd/ihash.h>
error_t
ports_transfer_right (void *tostruct,
void *fromstruct)
{
struct port_info *topi = tostruct;
struct port_info *frompi = fromstruct;
mach_port_t port;
int dereffrompi = 0;
int dereftopi = 0;
int hassendrights = 0;
error_t err;
mutex_lock (&_ports_lock);
/* Fetch the port in FROMPI and clear its use */
port = frompi->port_right;
if (port != MACH_PORT_NULL)
{
ihash_locp_remove (frompi->bucket->htable, frompi->hentry);
frompi->port_right = MACH_PORT_NULL;
if (frompi->flags & PORT_HAS_SENDRIGHTS)
{
frompi->flags &= ~PORT_HAS_SENDRIGHTS;
hassendrights = 1;
dereffrompi = 1;
}
}
/* Destroy the existing right in TOPI. */
if (topi->port_right != MACH_PORT_NULL)
{
ihash_locp_remove (topi->bucket->htable, topi->hentry);
err = mach_port_mod_refs (mach_task_self (), topi->port_right,
MACH_PORT_RIGHT_RECEIVE, -1);
if ((topi->flags & PORT_HAS_SENDRIGHTS) && !hassendrights)
{
dereftopi = 1;
topi->flags &= ~PORT_HAS_SENDRIGHTS;
}
else if (((topi->flags & PORT_HAS_SENDRIGHTS) == 0) && hassendrights)
{
topi->flags |= PORT_HAS_SENDRIGHTS;
topi->refcnt++;
}
}
/* Install the new right in TOPI. */
topi->port_right = port;
topi->cancel_threshold = frompi->cancel_threshold;
topi->mscount = frompi->mscount;
if (port)
{
ihash_add (topi->bucket->htable, port, topi, &topi->hentry);
if (topi->bucket != frompi->bucket)
mach_port_move_member (mach_task_self (), port, topi->bucket->portset);
}
mutex_unlock (&_ports_lock);
/* Take care of any lowered reference counts. */
if (dereffrompi)
ports_port_deref (frompi);
if (dereftopi)
ports_port_deref (topi);
return 0;
}
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