1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
|
/* Transfer the receive right from one port structure to another
Copyright (C) 1996, 2003 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 <assert.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;
pthread_mutex_lock (&_ports_lock);
/* Fetch the port in FROMPI and clear its use */
port = frompi->port_right;
if (port != MACH_PORT_NULL)
{
pthread_rwlock_wrlock (&_ports_htable_lock);
hurd_ihash_locp_remove (&_ports_htable, frompi->ports_htable_entry);
hurd_ihash_locp_remove (&frompi->bucket->htable, frompi->hentry);
pthread_rwlock_unlock (&_ports_htable_lock);
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)
{
pthread_rwlock_wrlock (&_ports_htable_lock);
hurd_ihash_locp_remove (&_ports_htable, topi->ports_htable_entry);
hurd_ihash_locp_remove (&topi->bucket->htable, topi->hentry);
pthread_rwlock_unlock (&_ports_htable_lock);
err = mach_port_mod_refs (mach_task_self (), topi->port_right,
MACH_PORT_RIGHT_RECEIVE, -1);
assert_perror (err);
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;
refcounts_ref (&topi->refcounts, NULL);
}
}
/* Install the new right in TOPI. */
topi->port_right = port;
topi->cancel_threshold = frompi->cancel_threshold;
topi->mscount = frompi->mscount;
pthread_mutex_unlock (&_ports_lock);
if (port)
{
pthread_rwlock_wrlock (&_ports_htable_lock);
err = hurd_ihash_add (&_ports_htable, port, topi);
assert_perror (err);
err = hurd_ihash_add (&topi->bucket->htable, port, topi);
pthread_rwlock_unlock (&_ports_htable_lock);
assert_perror (err);
/* This is an optimization. It may fail. */
mach_port_set_protected_payload (mach_task_self (), port,
(unsigned long) topi);
if (topi->bucket != frompi->bucket)
{
err = mach_port_move_member (mach_task_self (), port,
topi->bucket->portset);
assert_perror (err);
}
}
/* Take care of any lowered reference counts. */
if (dereffrompi)
ports_port_deref (frompi);
if (dereftopi)
ports_port_deref (topi);
return 0;
}
|
