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
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
|
/* Replacement for mach_msg used in interruptible Hurd RPCs.
Copyright (C) 95, 96, 97, 98 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <mach.h>
#include <mach/mig_errors.h>
#include <mach/mig_support.h>
#include <hurd/signal.h>
#include "intr-msg.h"
error_t
_hurd_intr_rpc_mach_msg (mach_msg_header_t *msg,
mach_msg_option_t option,
mach_msg_size_t send_size,
mach_msg_size_t rcv_size,
mach_port_t rcv_name,
mach_msg_timeout_t timeout,
mach_port_t notify)
{
error_t err;
struct hurd_sigstate *ss;
int user_timeout;
if (_hurd_msgport_thread == MACH_PORT_NULL)
{
/* The signal thread is not set up yet, so we cannot do the
normal signal magic. Do a simple uninterruptible RPC instead. */
return __mach_msg (msg, option, send_size, rcv_size, rcv_name,
timeout, notify);
}
ss = _hurd_self_sigstate ();
/* Notice now if the user requested a timeout. OPTION may have the bit
added by interruption semantics, and we must distinguish. */
user_timeout = option & MACH_RCV_TIMEOUT;
/* Tell the signal thread that we are doing an interruptible RPC on
this port. If we get a signal and should return EINTR, the signal
thread will set this variable to MACH_PORT_NULL. The RPC might
return EINTR when some other thread gets a signal, in which case we
want to restart our call. */
ss->intr_port = msg->msgh_remote_port;
/* A signal may arrive here, after intr_port is set, but before
the mach_msg system call. The signal handler might do an
interruptible RPC, and clobber intr_port; then it would not be
set properly when we actually did send the RPC, and a later
signal wouldn't interrupt that RPC. So,
_hurd_setup_sighandler saves intr_port in the sigcontext, and
sigreturn restores it. */
message:
if (ss->cancel)
{
/* We have been cancelled. Don't do an RPC at all. */
ss->intr_port = MACH_PORT_NULL;
ss->cancel = 0;
return EINTR;
}
err = INTR_MSG_TRAP (msg, option, send_size,
rcv_size, rcv_name, timeout, notify);
switch (err)
{
case MACH_RCV_TIMED_OUT:
if (user_timeout)
/* The real user RPC timed out. */
break;
else
/* The operation was supposedly interrupted, but still has
not returned. Declare it interrupted. */
goto interrupted;
case MACH_SEND_INTERRUPTED: /* RPC didn't get out. */
case EINTR: /* Server not cooperating with interrupt. */
if (ss->intr_port != MACH_PORT_NULL)
/* If this signal was for us and it should interrupt calls, the
signal thread will have cleared SS->intr_port.
Since it's not cleared, the signal was for another thread,
or SA_RESTART is set. Restart the interrupted call. */
{
restart:
if (rcv_name != MACH_PORT_NULL)
/* Make sure we have a valid reply port. The one we were using
may have been destroyed by interruption. */
msg->msgh_local_port = rcv_name = __mig_get_reply_port ();
goto message;
}
/* FALLTHROUGH */
case MACH_RCV_PORT_DIED:
/* Server didn't respond to interrupt_operation,
so the signal thread destroyed the reply port. */
/* FALLTHROUGH */
interrupted:
err = EINTR;
/* The EINTR return indicates cancellation, so clear the flag. */
ss->cancel = 0;
break;
case MACH_RCV_INTERRUPTED: /* RPC sent; no reply. */
option &= ~MACH_SEND_MSG; /* Don't send again. */
if (ss->intr_port == MACH_PORT_NULL)
{
/* This signal or cancellation was for us. We need to wait for
the reply, but not hang forever. */
option |= MACH_RCV_TIMEOUT;
/* Never decrease the user's timeout. */
if (!user_timeout || timeout > _hurd_interrupted_rpc_timeout)
timeout = _hurd_interrupted_rpc_timeout;
}
goto message; /* Retry the receive. */
case MACH_MSG_SUCCESS:
if (option & MACH_RCV_MSG)
{
/* We got a reply. Was it EINTR? */
mig_reply_header_t *const reply = (void *) msg;
const union
{
mach_msg_type_t t;
int i;
} check =
{ t: {
MACH_MSG_TYPE_INTEGER_T,
MACH_MSG_TYPE_INTEGER_T,
1,
TRUE,
FALSE,
FALSE,
0
} };
if (msg->msgh_size == sizeof *reply &&
!(msg->msgh_bits & MACH_MSGH_BITS_COMPLEX) &&
*(int *) &reply->RetCodeType == check.i &&
reply->RetCode == EINTR)
{
/* It is indeed EINTR. Is the interrupt for us? */
if (ss->intr_port != MACH_PORT_NULL)
/* Nope; repeat the RPC.
XXX Resources moved? */
goto restart;
else
/* The EINTR return indicates cancellation, so clear the
flag. */
ss->cancel = 0;
}
}
break;
default: /* Quiet -Wswitch-enum. */
}
ss->intr_port = MACH_PORT_NULL;
return err;
}
|
