1 /* Replacement for mach_msg used in interruptible Hurd RPCs.
2 Copyright (C) 95, 96, 97, 98 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
15 You should have received a copy of the GNU Library General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If not,
17 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA. */
21 #include <mach/mig_errors.h>
22 #include <mach/mig_support.h>
23 #include <hurd/signal.h>
29 _hurd_intr_rpc_mach_msg (mach_msg_header_t
*msg
,
30 mach_msg_option_t option
,
31 mach_msg_size_t send_size
,
32 mach_msg_size_t rcv_size
,
34 mach_msg_timeout_t timeout
,
38 struct hurd_sigstate
*ss
;
41 if (_hurd_msgport_thread
== MACH_PORT_NULL
)
43 /* The signal thread is not set up yet, so we cannot do the
44 normal signal magic. Do a simple uninterruptible RPC instead. */
45 return __mach_msg (msg
, option
, send_size
, rcv_size
, rcv_name
,
49 ss
= _hurd_self_sigstate ();
51 /* Notice now if the user requested a timeout. OPTION may have the bit
52 added by interruption semantics, and we must distinguish. */
53 user_timeout
= option
& MACH_RCV_TIMEOUT
;
55 /* Tell the signal thread that we are doing an interruptible RPC on
56 this port. If we get a signal and should return EINTR, the signal
57 thread will set this variable to MACH_PORT_NULL. The RPC might
58 return EINTR when some other thread gets a signal, in which case we
59 want to restart our call. */
60 ss
->intr_port
= msg
->msgh_remote_port
;
62 /* A signal may arrive here, after intr_port is set, but before
63 the mach_msg system call. The signal handler might do an
64 interruptible RPC, and clobber intr_port; then it would not be
65 set properly when we actually did send the RPC, and a later
66 signal wouldn't interrupt that RPC. So,
67 _hurd_setup_sighandler saves intr_port in the sigcontext, and
68 sigreturn restores it. */
74 /* We have been cancelled. Don't do an RPC at all. */
75 ss
->intr_port
= MACH_PORT_NULL
;
80 err
= INTR_MSG_TRAP (msg
, option
, send_size
,
81 rcv_size
, rcv_name
, timeout
, notify
);
85 case MACH_RCV_TIMED_OUT
:
87 /* The real user RPC timed out. */
90 /* The operation was supposedly interrupted, but still has
91 not returned. Declare it interrupted. */
94 case MACH_SEND_INTERRUPTED
: /* RPC didn't get out. */
95 case EINTR
: /* Server not cooperating with interrupt. */
96 if (ss
->intr_port
!= MACH_PORT_NULL
)
97 /* If this signal was for us and it should interrupt calls, the
98 signal thread will have cleared SS->intr_port.
99 Since it's not cleared, the signal was for another thread,
100 or SA_RESTART is set. Restart the interrupted call. */
103 if (rcv_name
!= MACH_PORT_NULL
)
104 /* Make sure we have a valid reply port. The one we were using
105 may have been destroyed by interruption. */
106 msg
->msgh_local_port
= rcv_name
= __mig_get_reply_port ();
111 case MACH_RCV_PORT_DIED
:
112 /* Server didn't respond to interrupt_operation,
113 so the signal thread destroyed the reply port. */
119 /* The EINTR return indicates cancellation, so clear the flag. */
123 case MACH_RCV_INTERRUPTED
: /* RPC sent; no reply. */
124 option
&= ~MACH_SEND_MSG
; /* Don't send again. */
125 if (ss
->intr_port
== MACH_PORT_NULL
)
127 /* This signal or cancellation was for us. We need to wait for
128 the reply, but not hang forever. */
129 option
|= MACH_RCV_TIMEOUT
;
130 /* Never decrease the user's timeout. */
131 if (!user_timeout
|| timeout
> _hurd_interrupted_rpc_timeout
)
132 timeout
= _hurd_interrupted_rpc_timeout
;
134 goto message
; /* Retry the receive. */
136 case MACH_MSG_SUCCESS
:
137 if (option
& MACH_RCV_MSG
)
139 /* We got a reply. Was it EINTR? */
140 mig_reply_header_t
*const reply
= (void *) msg
;
147 MACH_MSG_TYPE_INTEGER_T
,
148 MACH_MSG_TYPE_INTEGER_T
,
155 if (msg
->msgh_size
== sizeof *reply
&&
156 !(msg
->msgh_bits
& MACH_MSGH_BITS_COMPLEX
) &&
157 *(int *) &reply
->RetCodeType
== check
.i
&&
158 reply
->RetCode
== EINTR
)
160 /* It is indeed EINTR. Is the interrupt for us? */
161 if (ss
->intr_port
!= MACH_PORT_NULL
)
162 /* Nope; repeat the RPC.
163 XXX Resources moved? */
166 /* The EINTR return indicates cancellation, so clear the
173 default: /* Quiet -Wswitch-enum. */
176 ss
->intr_port
= MACH_PORT_NULL
;