1 # This file is part of NIT (http://www.nitlanguage.org).
3 # Copyright 2011 Alexis Laferrière <alexis.laf@xymus.net>
5 # Licensed under the Apache License, Version 2.0 (the "License");
6 # you may not use this file except in compliance with the License.
7 # You may obtain a copy of the License at
9 # http://www.apache.org/licenses/LICENSE-2.0
11 # Unless required by applicable law or agreed to in writing, software
12 # distributed under the License is distributed on an "AS IS" BASIS,
13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 # See the License for the specific language governing permissions and
15 # limitations under the License.
17 # Module to manage standard C signals
19 # Common usage imply 5 steps:
21 # 1. Implement the `SignalHandler` interface
22 # 2. `redef receive_signal_unsafe` to handle `sigsegv`
23 # 3. `redef receive_signal` to handle other signals safely
24 # 4, Notify what signals to handle with `handle_signal`
25 # 5. If using the safe handler method, routinely call `check_signals`
33 # redef fun receive_signal(signal)
35 # print "received safely {signal}"
36 # if signal == sigalarm then print "Alarm!"
38 # redef fun receive_signal_unsafe( signal ) do print "received unsafely {signal}"
41 # var r = new MyReceiver
43 # # Handle `sigsegv` signal unsafely (the only way for this one)
44 # r.handle_signal(sigsegv, false)
46 # # Handle `sigint` and `sigalarm` safely
47 # r.handle_signal(sigint, true)
48 # r.handle_signal(sigalarm, true)
50 # # Ask system to receive a `sigalarm` signal in 1 second
54 # # Check signals and callback `receive_signal`
55 # var hit = check_signals
64 #define _POSIX_SOURCE 1
70 void (*nit_SignalHandler_receive_signal)(void* self, long signal);
73 Structure to manage each possible signals
74 are used in an array of 32 maximum signals.
75 This array is global to the software.
77 struct nit_signals_ent {
78 char raised; /* !=0 if has been raised */
79 void* handler; /* instance to receive call */
80 char safely; /* if !=0 then manage signal safely, otherwise react when raised */
81 } nit_signals_list[32] = {0x0};
83 /* Receiver to all signals
84 If unsafe, it calls directly the Nit receiver,
85 otherwise it marks the signal as raised and returns.
87 void receiver(int sig)
89 if (sig < 32 && sig >=0)
91 if (nit_signals_list[sig].safely) {
92 nit_signals_list[sig].raised += 1;
94 nit_SignalHandler_receive_signal(nit_signals_list[sig].handler, sig);
100 # Receives the callback from system when a given signal arise
101 interface SignalHandler
102 # Invoked after a call to `check_signals` if a signal has been raised
103 # (should be redefed by subclasses)
105 # Should be used by most signals except `sigkill` and `sigstop` since they
106 # cannot be caught, blocked or ignored.
109 # super SignalHandler
111 # redef fun receive_signal(signal) do print "received safely {signal}"
114 # var r = new MyReceiver
115 # r.handle_signal(sigint, true) # will call back when "check_signals" is called
117 # check_signals # if a signal was received, it will invoke `r.receive_signal`
118 fun receive_signal
(signal
: Int) do end
120 # Called immediatly on receiving an unsafe signal (should be redefed by subclasses)
122 # Should be used for `sigkill` and `sigstop` since they cannot be caught,
123 # blocked or ignored.
125 # You should consider this methods as being fragile. It should be implemented in C
126 # and you should not do too much callbacks to Nit.
129 # super SignalHandler
131 # redef fun receive_signal_unsafe(signal) do print "received unsafely {signal}"
134 # var r = new MyReceiver
135 # r.handle_signal(sigsegv, false) # `r.receive_signal_unsafe` will be invoked on sigsegv
136 fun receive_signal_unsafe
(signal
: Int) do end
138 # Set the receiver as the handler of the signal
140 # If `safely`, receiver will be called when `check_signals` in invoked
141 # otherwise the receiver is invoked when the signal is raised, it may
142 # crash the Nit system but is unavoidable for unstoppable signals.
143 fun handle_signal
(signal
: Int, safely
: Bool) import receive_signal
`{
144 SignalHandler last_handler;
145 if (signal < 32 && signal >=0) {
146 struct sigaction act;
147 sigemptyset(&act.sa_mask);
149 act.sa_handler = receiver;
151 sigaction(signal, &act, NULL);
153 last_handler = (SignalHandler)nit_signals_list[signal].handler;
154 if (last_handler != NULL)
155 SignalHandler_decr_ref(last_handler);
157 nit_signals_list[signal].handler = self;
158 SignalHandler_incr_ref(self);
160 nit_signals_list[signal].safely = safely;
161 nit_SignalHandler_receive_signal = SignalHandler_receive_signal;
165 # Set to ignore the signal
166 fun ignore_signal
(signal
: Int) `{
167 SignalHandler last_handler;
168 if (signal < 32 && signal >=0) {
169 struct sigaction act;
170 sigemptyset(&act.sa_mask);
172 act.sa_handler = SIG_IGN;
173 sigaction(signal, &act, NULL);
175 last_handler = (SignalHandler)nit_signals_list[signal].handler;
176 if (last_handler != NULL)
177 SignalHandler_decr_ref(last_handler);
181 # Set default action for the signal
182 fun default_signal
(signal
: Int) `{
183 SignalHandler last_handler;
184 if (signal < 32 && signal >=0) {
185 struct sigaction act;
186 sigemptyset(&act.sa_mask);
188 act.sa_handler = SIG_DFL;
189 sigaction(signal, &act, NULL);
191 last_handler = (SignalHandler)nit_signals_list[signal].handler;
192 if (last_handler != NULL)
193 SignalHandler_decr_ref(last_handler);
198 redef interface Object
200 # Check signals for safe operation
201 # will callback receiver of raised signals
202 # can callback any instance of SignalHandler, not just this one
203 protected fun check_signals
: Bool is extern import SignalHandler.receive_signal
`{
205 int raised_something = 0;
207 for (sig = 0; sig < 32; sig ++)
208 if (nit_signals_list[sig].raised) {
209 nit_signals_list[sig].raised = 0;
210 raised_something = 1;
211 SignalHandler handler = (SignalHandler)nit_signals_list[sig].handler;
212 SignalHandler_receive_signal(handler, sig);
215 return raised_something;
219 # can callback any instance of SignalHandler, not just this one
220 protected fun set_alarm
(sec
: Int) `{ alarm(sec); `}
224 # Send a signal to the process
225 fun signal(signal: Int) do native_kill(id, signal)
227 # Send the kill signal to the process
228 fun kill do signal(sigkill)
230 # Native implementation of `signal
`
231 private fun native_kill(pid, signal: Int) `{ kill(pid, signal); `}
234 # Hang up detected on controlling terminal or death of controlling process
235 fun sighup
: Int do return 1
237 # Issued if the user sends an interrupt signal
238 fun sigint
: Int do return 2
240 # Issued if the user sends a quit signal
241 fun sigquit
: Int do return 3
243 # Issued if the user attempts to execute an illegal, malformed, unknown, or privileged instruction
244 fun sigill
: Int do return 4
246 # Issued when an exception occurs: a condition that a debugger has requested to be informed of
247 fun sigtrap
: Int do return 5
249 # This signal is sent to a process to tell it to abort, i. e. to terminate
250 fun sigabrt
: Int do return 6
252 # This signal is sent to a process when it causes a bus error
253 fun sigbus
: Int do return 7
255 # Issued if an illegal mathematical operation is attempted
256 fun sigfpe
: Int do return 8
258 # If a process gets this signal it must quit immediately and will not perform any clean-up operations
259 fun sigkill
: Int do return 9
261 # Sent to a process to indicate user-defined conditions
262 fun sigusr1
: Int do return 10
264 # Sent to a process when it makes an invalid virtual memory reference, or segmentation fault
265 fun sigsegv
: Int do return 11
267 # Sent to a process to indicate user-defined conditions
268 fun sigusr2
: Int do return 12
270 # Sent to a process when it attempts to write to a pipe without a process connected to the other end
271 fun sigpipe
: Int do return 13
274 fun sigalarm
: Int do return 14
276 # Software termination signal
277 fun sigterm
: Int do return 15
279 # Sent to a process when a child process terminates or is interrupted
280 fun sigchild
: Int do return 17
282 # Tell the operating system to continue (restart) a process previously paused by the SIGSTOP or SIGTSTP signal
283 fun sigcont
: Int do return 18
285 # Tell the operating system to stop a process
286 fun sigstop
: Int do return 19
288 # Sent to a process by its terminal to request it to stop temporarily
289 fun sigtstp
: Int do return 20
291 # Sent to a process when a socket has urgent or out-of-band data available to read
292 fun sigurg
: Int do return 23
294 # Sent to a process when it has used the CPU for a duration that exceeds a user-settable value
295 fun sigxcpu
: Int do return 24
297 # Sent to a process when it grows a file larger than the maximum allowed size
298 fun sigxfsz
: Int do return 25
300 # Virtual timer expired
301 fun sigvtalrm
: Int do return 26
303 # Profiling timer expired
304 fun sigprof
: Int do return 27
306 # Sent to a process when its controlling terminal changes its window size
307 fun sigwinch
: Int do return 28
309 # Sent to a process when the system experiences a power failure
310 fun sigpwr
: Int do return 30
312 # Sent to a process when it passes a bad argument to a system call
313 fun sigsys
: Int do return 31