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54da5be3 RM |
1 | /* Replacement for mach_msg used in interruptible Hurd RPCs. |
2 | Copyright (C) 1995 Free Software Foundation, Inc. | |
3 | This file is part of the GNU C Library. | |
4 | ||
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. | |
9 | ||
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. | |
14 | ||
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 | |
17 | not, write to the Free Software Foundation, Inc., 675 Mass Ave, | |
18 | Cambridge, MA 02139, USA. */ | |
19 | ||
20 | #include <mach.h> | |
21 | #include <mach/mig_errors.h> | |
22 | #include <hurd/signal.h> | |
23 | ||
3fe9de0d RM |
24 | #include "intr-msg.h" |
25 | ||
26 | ||
54da5be3 RM |
27 | error_t |
28 | _hurd_intr_rpc_mach_msg (mach_msg_header_t *msg, | |
29 | mach_msg_option_t option, | |
30 | mach_msg_size_t send_size, | |
31 | mach_msg_size_t rcv_size, | |
32 | mach_port_t rcv_name, | |
33 | mach_msg_timeout_t timeout, | |
34 | mach_port_t notify) | |
35 | { | |
36 | struct hurd_sigstate *ss = _hurd_self_sigstate (); | |
37 | error_t err; | |
a993273c RM |
38 | /* Notice now if the user requested a timeout. OPTION may have the bit |
39 | added by interruption semantics, and we must distinguish. */ | |
40 | int user_timeout = option & MACH_RCV_TIMEOUT; | |
54da5be3 RM |
41 | |
42 | /* Tell the signal thread that we are doing an interruptible RPC on | |
43 | this port. If we get a signal and should return EINTR, the signal | |
44 | thread will set this variable to MACH_PORT_NULL. The RPC might | |
45 | return EINTR when some other thread gets a signal, in which case we | |
46 | want to restart our call. */ | |
47 | ss->intr_port = msg->msgh_remote_port; | |
48 | ||
49 | /* A signal may arrive here, after intr_port is set, but before | |
50 | the mach_msg system call. The signal handler might do an | |
51 | interruptible RPC, and clobber intr_port; then it would not be | |
52 | set properly when we actually did send the RPC, and a later | |
53 | signal wouldn't interrupt that RPC. So, | |
54 | _hurd_setup_sighandler saves intr_port in the sigcontext, and | |
55 | sigreturn restores it. */ | |
56 | ||
57 | message: | |
58 | ||
59 | if (ss->cancel) | |
60 | { | |
61 | err = EINTR; | |
62 | ss->cancel = 0; | |
63 | } | |
64 | else | |
3fe9de0d RM |
65 | err = INTR_MSG_TRAP (msg, option, send_size, |
66 | rcv_size, rcv_name, timeout, notify); | |
54da5be3 RM |
67 | |
68 | switch (err) | |
69 | { | |
a993273c RM |
70 | case MACH_RCV_TIMED_OUT: |
71 | if (user_timeout) | |
72 | /* The real user RPC timed out. */ | |
73 | break; | |
74 | else | |
75 | /* The operation was supposedly interrupted, but still has | |
76 | not returned. Declare it interrupted. */ | |
77 | goto interrupted; | |
78 | ||
54da5be3 | 79 | case MACH_SEND_INTERRUPTED: /* RPC didn't get out. */ |
44c8d1a2 | 80 | case EINTR: /* Server not cooperating with interrupt. */ |
54da5be3 RM |
81 | if (ss->intr_port != MACH_PORT_NULL) |
82 | /* If this signal was for us and it should interrupt calls, the | |
83 | signal thread will have cleared SS->intr_port. | |
84 | Since it's not cleared, the signal was for another thread, | |
85 | or SA_RESTART is set. Restart the interrupted call. */ | |
86 | goto message; | |
87 | /* FALLTHROUGH */ | |
88 | ||
89 | case MACH_RCV_PORT_DIED: | |
90 | /* Server didn't respond to interrupt_operation, | |
91 | so the signal thread destroyed the reply port. */ | |
92 | /* FALLTHROUGH */ | |
93 | ||
a993273c | 94 | interrupted: |
54da5be3 RM |
95 | err = EINTR; |
96 | ||
97 | /* The EINTR return indicates cancellation, so clear the flag. */ | |
98 | ss->cancel = 0; | |
99 | break; | |
100 | ||
101 | case MACH_RCV_INTERRUPTED: /* RPC sent; no reply. */ | |
102 | option &= ~MACH_SEND_MSG; /* Don't send again. */ | |
103 | if (ss->intr_port == MACH_PORT_NULL) | |
104 | { | |
105 | /* This signal or cancellation was for us. We need to wait for | |
106 | the reply, but not hang forever. */ | |
107 | option |= MACH_RCV_TIMEOUT; | |
a993273c RM |
108 | /* Never decrease the user's timeout. */ |
109 | if (!user_timeout || timeout > _hurd_interrupted_rpc_timeout) | |
110 | timeout = _hurd_interrupted_rpc_timeout; | |
54da5be3 RM |
111 | } |
112 | goto message; /* Retry the receive. */ | |
113 | ||
114 | case MACH_MSG_SUCCESS: | |
115 | if (option & MACH_RCV_MSG) | |
116 | { | |
117 | /* We got a reply. Was it EINTR? */ | |
118 | mig_reply_header_t *const reply = (void *) msg; | |
119 | const union | |
120 | { | |
121 | mach_msg_type_t t; | |
122 | int i; | |
123 | } check = | |
124 | { t: { | |
125 | MACH_MSG_TYPE_INTEGER_32, | |
126 | 32, | |
127 | 1, | |
128 | TRUE, | |
129 | FALSE, | |
130 | FALSE, | |
131 | 0 | |
132 | } }; | |
133 | if (msg->msgh_size == sizeof *reply && | |
134 | !(msg->msgh_bits & MACH_MSGH_BITS_COMPLEX) && | |
135 | *(int *) &reply->RetCodeType == check.i && | |
136 | reply->RetCode == EINTR) | |
137 | { | |
138 | /* It is indeed EINTR. Is the interrupt for us? */ | |
139 | if (ss->intr_port != MACH_PORT_NULL) | |
140 | /* Nope; repeat the RPC. | |
141 | XXX Resources moved? */ | |
142 | goto message; | |
143 | else | |
144 | /* The EINTR return indicates cancellation, so clear the | |
145 | flag. */ | |
146 | ss->cancel = 0; | |
147 | } | |
148 | } | |
149 | break; | |
150 | ||
151 | default: /* Quiet -Wswitch-enum. */ | |
152 | } | |
153 | ||
154 | ss->intr_port = MACH_PORT_NULL; | |
155 | ||
156 | return err; | |
157 | } |