Update.
[glibc.git] / hurd / intr-msg.c
blobeb7adbef663a278350d441fbc788a29292fd40c4
1 /* Replacement for mach_msg used in interruptible Hurd RPCs.
2 Copyright (C) 1995, 1996, 1997 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. */
20 #include <mach.h>
21 #include <mach/mig_errors.h>
22 #include <mach/mig_support.h>
23 #include <hurd/signal.h>
25 #include "intr-msg.h"
28 error_t
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,
33 mach_port_t rcv_name,
34 mach_msg_timeout_t timeout,
35 mach_port_t notify)
37 struct hurd_sigstate *ss = _hurd_self_sigstate ();
38 error_t err;
39 /* Notice now if the user requested a timeout. OPTION may have the bit
40 added by interruption semantics, and we must distinguish. */
41 int user_timeout = option & MACH_RCV_TIMEOUT;
43 /* Tell the signal thread that we are doing an interruptible RPC on
44 this port. If we get a signal and should return EINTR, the signal
45 thread will set this variable to MACH_PORT_NULL. The RPC might
46 return EINTR when some other thread gets a signal, in which case we
47 want to restart our call. */
48 ss->intr_port = msg->msgh_remote_port;
50 /* A signal may arrive here, after intr_port is set, but before
51 the mach_msg system call. The signal handler might do an
52 interruptible RPC, and clobber intr_port; then it would not be
53 set properly when we actually did send the RPC, and a later
54 signal wouldn't interrupt that RPC. So,
55 _hurd_setup_sighandler saves intr_port in the sigcontext, and
56 sigreturn restores it. */
58 message:
60 if (ss->cancel)
62 /* We have been cancelled. Don't do an RPC at all. */
63 ss->intr_port = MACH_PORT_NULL;
64 ss->cancel = 0;
65 return EINTR;
68 err = INTR_MSG_TRAP (msg, option, send_size,
69 rcv_size, rcv_name, timeout, notify);
71 switch (err)
73 case MACH_RCV_TIMED_OUT:
74 if (user_timeout)
75 /* The real user RPC timed out. */
76 break;
77 else
78 /* The operation was supposedly interrupted, but still has
79 not returned. Declare it interrupted. */
80 goto interrupted;
82 case MACH_SEND_INTERRUPTED: /* RPC didn't get out. */
83 case EINTR: /* Server not cooperating with interrupt. */
84 if (ss->intr_port != MACH_PORT_NULL)
85 /* If this signal was for us and it should interrupt calls, the
86 signal thread will have cleared SS->intr_port.
87 Since it's not cleared, the signal was for another thread,
88 or SA_RESTART is set. Restart the interrupted call. */
90 restart:
91 if (rcv_name != MACH_PORT_NULL)
92 /* Make sure we have a valid reply port. The one we were using
93 may have been destroyed by interruption. */
94 msg->msgh_local_port = rcv_name = __mig_get_reply_port ();
95 goto message;
97 /* FALLTHROUGH */
99 case MACH_RCV_PORT_DIED:
100 /* Server didn't respond to interrupt_operation,
101 so the signal thread destroyed the reply port. */
102 /* FALLTHROUGH */
104 interrupted:
105 err = EINTR;
107 /* The EINTR return indicates cancellation, so clear the flag. */
108 ss->cancel = 0;
109 break;
111 case MACH_RCV_INTERRUPTED: /* RPC sent; no reply. */
112 option &= ~MACH_SEND_MSG; /* Don't send again. */
113 if (ss->intr_port == MACH_PORT_NULL)
115 /* This signal or cancellation was for us. We need to wait for
116 the reply, but not hang forever. */
117 option |= MACH_RCV_TIMEOUT;
118 /* Never decrease the user's timeout. */
119 if (!user_timeout || timeout > _hurd_interrupted_rpc_timeout)
120 timeout = _hurd_interrupted_rpc_timeout;
122 goto message; /* Retry the receive. */
124 case MACH_MSG_SUCCESS:
125 if (option & MACH_RCV_MSG)
127 /* We got a reply. Was it EINTR? */
128 mig_reply_header_t *const reply = (void *) msg;
129 const union
131 mach_msg_type_t t;
132 int i;
133 } check =
134 { t: {
135 MACH_MSG_TYPE_INTEGER_T,
136 MACH_MSG_TYPE_INTEGER_T,
138 TRUE,
139 FALSE,
140 FALSE,
142 } };
143 if (msg->msgh_size == sizeof *reply &&
144 !(msg->msgh_bits & MACH_MSGH_BITS_COMPLEX) &&
145 *(int *) &reply->RetCodeType == check.i &&
146 reply->RetCode == EINTR)
148 /* It is indeed EINTR. Is the interrupt for us? */
149 if (ss->intr_port != MACH_PORT_NULL)
150 /* Nope; repeat the RPC.
151 XXX Resources moved? */
152 goto restart;
153 else
154 /* The EINTR return indicates cancellation, so clear the
155 flag. */
156 ss->cancel = 0;
159 break;
161 default: /* Quiet -Wswitch-enum. */
164 ss->intr_port = MACH_PORT_NULL;
166 return err;