--- /dev/null
+# This file is part of NIT (http://www.nitlanguage.org).
+#
+# Copyright 2011 Alexis Laferrière <alexis.laf@xymus.net>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# ANSI C signal handling
+#
+# Common usage imply 5 steps:
+#
+# 1. Implement the `SignalHandler` interface
+# 2. `redef receive_signal_unsafe` to handle `sigsegv`
+# 3. `redef receive_signal` to handle other signals safely
+# 4, Notify what signals to handle with `handle_signal`
+# 5. If using the safe handler method, routinely call `check_signals`
+#
+# Usage example:
+#
+# ~~~~
+# class MyReceiver
+# super SignalHandler
+#
+# redef fun receive_signal(signal)
+# do
+# print "received safely {signal}"
+# if signal == sigalarm then print "Alarm!"
+# end
+# redef fun receive_signal_unsafe( signal ) do print "received unsafely {signal}"
+# end
+#
+# var r = new MyReceiver
+#
+# # Handle `sigsegv` signal unsafely (the only way for this one)
+# r.handle_signal(sigsegv, false)
+#
+# # Handle `sigint` and `sigalarm` safely
+# r.handle_signal(sigint, true)
+# r.handle_signal(sigalarm, true)
+#
+# # Ask system to receive a `sigalarm` signal in 1 second
+# set_alarm(1)
+#
+# loop
+# # Check signals and callback `receive_signal`
+# var hit = check_signals
+#
+# if hit then break
+# end
+# ~~~~
+module signals
+
+`{
+ #undef _POSIX_SOURCE
+ #define _POSIX_SOURCE 1
+ #include <signal.h>
+ #include <stdio.h>
+ #include <unistd.h>
+
+ /*
+ */
+ void (*nit_SignalHandler_receive_signal)(void* self, long signal);
+
+ /*
+ Structure to manage each possible signals
+ are used in an array of 32 maximum signals.
+ This array is global to the software.
+ */
+ struct nit_signals_ent {
+ char raised; /* !=0 if has been raised */
+ void* handler; /* instance to receive call */
+ char safely; /* if !=0 then manage signal safely, otherwise react when raised */
+ } nit_signals_list[32] = {{0}};
+
+ /* Receiver to all signals
+ If unsafe, it calls directly the Nit receiver,
+ otherwise it marks the signal as raised and returns.
+ */
+ void receiver(int sig)
+ {
+ if (sig < 32 && sig >=0)
+ {
+ if (nit_signals_list[sig].safely) {
+ nit_signals_list[sig].raised += 1;
+ } else {
+ nit_SignalHandler_receive_signal(nit_signals_list[sig].handler, sig);
+ }
+ }
+ }
+`}
+
+# Receives the callback from system when a given signal arise
+interface SignalHandler
+ # Invoked after a call to `check_signals` if a signal has been raised
+ # (should be redefed by subclasses)
+ #
+ # Should be used by most signals except `sigkill` and `sigstop` since they
+ # cannot be caught, blocked or ignored.
+ #
+ # class MyReceiver
+ # super SignalHandler
+ #
+ # redef fun receive_signal(signal) do print "received safely {signal}"
+ # end
+ #
+ # var r = new MyReceiver
+ # r.handle_signal(sigint, true) # will call back when "check_signals" is called
+ # # ...
+ # check_signals # if a signal was received, it will invoke `r.receive_signal`
+ fun receive_signal(signal: Int) do end
+
+ # Called immediatly on receiving an unsafe signal (should be redefed by subclasses)
+ #
+ # Should be used for `sigkill` and `sigstop` since they cannot be caught,
+ # blocked or ignored.
+ #
+ # You should consider this methods as being fragile. It should be implemented in C
+ # and you should not do too much callbacks to Nit.
+ #
+ # class MyReceiver
+ # super SignalHandler
+ #
+ # redef fun receive_signal_unsafe(signal) do print "received unsafely {signal}"
+ # end
+ #
+ # var r = new MyReceiver
+ # r.handle_signal(sigsegv, false) # `r.receive_signal_unsafe` will be invoked on sigsegv
+ fun receive_signal_unsafe(signal: Int) do end
+
+ # Set the receiver as the handler of the signal
+ #
+ # If `safely`, receiver will be called when `check_signals` in invoked
+ # otherwise the receiver is invoked when the signal is raised, it may
+ # crash the Nit system but is unavoidable for unstoppable signals.
+ fun handle_signal(signal: Int, safely: Bool) import receive_signal `{
+ if (signal < 32 && signal >=0) {
+ struct sigaction act;
+ sigemptyset(&act.sa_mask);
+ act.sa_flags = 0;
+ act.sa_handler = receiver;
+
+ sigaction(signal, &act, NULL);
+
+ #ifdef SignalHandler_decr_ref
+ SignalHandler last_handler = (SignalHandler)nit_signals_list[signal].handler;
+ if (last_handler != NULL)
+ SignalHandler_decr_ref(last_handler);
+ #endif
+
+ nit_signals_list[signal].handler = self;
+
+ #ifdef SignalHandler_incr_ref
+ SignalHandler_incr_ref(self);
+ #endif
+
+ nit_signals_list[signal].safely = safely;
+
+ nit_SignalHandler_receive_signal =
+ (void (*)(void*, long))&SignalHandler_receive_signal;
+ }
+ `}
+
+ # Set to ignore the signal
+ fun ignore_signal(signal: Int) `{
+ if (signal < 32 && signal >=0) {
+ struct sigaction act;
+ sigemptyset(&act.sa_mask);
+ act.sa_flags = 0;
+ act.sa_handler = SIG_IGN;
+ sigaction(signal, &act, NULL);
+
+ #ifdef SignalHandler_decr_ref
+ SignalHandler last_handler = (SignalHandler)nit_signals_list[signal].handler;
+ if (last_handler != NULL)
+ SignalHandler_decr_ref(last_handler);
+ #endif
+ }
+ `}
+
+ # Set default action for the signal
+ fun default_signal(signal: Int) `{
+ if (signal < 32 && signal >=0) {
+ struct sigaction act;
+ sigemptyset(&act.sa_mask);
+ act.sa_flags = 0;
+ act.sa_handler = SIG_DFL;
+ sigaction(signal, &act, NULL);
+
+ #ifdef SignalHandler_decr_ref
+ SignalHandler last_handler = (SignalHandler)nit_signals_list[signal].handler;
+ if (last_handler != NULL)
+ SignalHandler_decr_ref(last_handler);
+ #endif
+ }
+ `}
+end
+
+# Check signals for safe operation
+# will callback receiver of raised signals
+# can callback any instance of SignalHandler, not just this one
+fun check_signals: Bool is extern import SignalHandler.receive_signal `{
+ int sig;
+ int raised_something = 0;
+
+ for (sig = 0; sig < 32; sig ++)
+ if (nit_signals_list[sig].raised) {
+ nit_signals_list[sig].raised = 0;
+ raised_something = 1;
+ SignalHandler handler = (SignalHandler)nit_signals_list[sig].handler;
+ SignalHandler_receive_signal(handler, sig);
+ }
+
+ return raised_something;
+`}
+
+# Set alarm signal
+# can callback any instance of SignalHandler, not just this one
+fun set_alarm(sec: Int) `{ alarm(sec); `}
+
+redef class Process
+ # Send a signal to the process
+ fun signal(signal: Int) do native_kill(id, signal)
+
+ # Send the kill signal to the process
+ fun kill do signal(sigkill)
+
+ # Native implementation of `signal`
+ private fun native_kill(pid, signal: Int) `{ kill(pid, signal); `}
+end
+
+# Hang up detected on controlling terminal or death of controlling process
+fun sighup: Int do return 1
+
+# Issued if the user sends an interrupt signal
+fun sigint: Int do return 2
+
+# Issued if the user sends a quit signal
+fun sigquit: Int do return 3
+
+# Issued if the user attempts to execute an illegal, malformed, unknown, or privileged instruction
+fun sigill: Int do return 4
+
+# Issued when an exception occurs: a condition that a debugger has requested to be informed of
+fun sigtrap: Int do return 5
+
+# This signal is sent to a process to tell it to abort, i. e. to terminate
+fun sigabrt: Int do return 6
+
+# This signal is sent to a process when it causes a bus error
+fun sigbus: Int do return 7
+
+# Issued if an illegal mathematical operation is attempted
+fun sigfpe: Int do return 8
+
+# If a process gets this signal it must quit immediately and will not perform any clean-up operations
+fun sigkill: Int do return 9
+
+# Sent to a process to indicate user-defined conditions
+fun sigusr1: Int do return 10
+
+# Sent to a process when it makes an invalid virtual memory reference, or segmentation fault
+fun sigsegv: Int do return 11
+
+# Sent to a process to indicate user-defined conditions
+fun sigusr2: Int do return 12
+
+# Sent to a process when it attempts to write to a pipe without a process connected to the other end
+fun sigpipe: Int do return 13
+
+# Alarm Clock signal
+fun sigalarm: Int do return 14
+
+# Software termination signal
+fun sigterm: Int do return 15
+
+# Sent to a process when a child process terminates or is interrupted
+fun sigchild: Int do return 17
+
+# Tell the operating system to continue (restart) a process previously paused by the SIGSTOP or SIGTSTP signal
+fun sigcont: Int do return 18
+
+# Tell the operating system to stop a process
+fun sigstop: Int do return 19
+
+# Sent to a process by its terminal to request it to stop temporarily
+fun sigtstp: Int do return 20
+
+# Sent to a process when a socket has urgent or out-of-band data available to read
+fun sigurg: Int do return 23
+
+# Sent to a process when it has used the CPU for a duration that exceeds a user-settable value
+fun sigxcpu: Int do return 24
+
+# Sent to a process when it grows a file larger than the maximum allowed size
+fun sigxfsz: Int do return 25
+
+# Virtual timer expired
+fun sigvtalrm: Int do return 26
+
+# Profiling timer expired
+fun sigprof: Int do return 27
+
+# Sent to a process when its controlling terminal changes its window size
+fun sigwinch: Int do return 28
+
+# Sent to a process when the system experiences a power failure
+fun sigpwr: Int do return 30
+
+# Sent to a process when it passes a bad argument to a system call
+fun sigsys: Int do return 31