# See the License for the specific language governing permissions and
# limitations under the License.
-# Module to manage standard C signals
+# 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
`{
#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
*/
struct nit_signals_ent {
char raised; /* !=0 if has been raised */
- SignalHandler handler; /* instance to receive call */
+ void* handler; /* instance to receive call */
char safely; /* if !=0 then manage signal safely, otherwise react when raised */
- } nit_signals_list[32] = {0x0};
+ } nit_signals_list[32] = {{0}};
/* Receiver to all signals
If unsafe, it calls directly the Nit receiver,
if (nit_signals_list[sig].safely) {
nit_signals_list[sig].raised += 1;
} else {
- SignalHandler_receive_signal(nit_signals_list[sig].handler, sig);
+ nit_SignalHandler_receive_signal(nit_signals_list[sig].handler, sig);
}
}
}
# Receives the callback from system when a given signal arise
interface SignalHandler
- # Called on any signal received
- fun receive_signal(signal: Int) `{
- `}
+ # 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 on any unsafe signal received
- fun receive_signal_unsafe(signal: Int) `{
- `}
+ # 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 `{
- SignalHandler last_handler;
+ #
+ # 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);
sigaction(signal, &act, NULL);
- last_handler = nit_signals_list[signal].handler;
+ #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 = recv;
- SignalHandler_incr_ref(recv);
+ 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 = SignalHandler_receive_signal;
}
`}
# Set to ignore the signal
fun ignore_signal(signal: Int) `{
- SignalHandler last_handler;
if (signal < 32 && signal >=0) {
struct sigaction act;
sigemptyset(&act.sa_mask);
act.sa_handler = SIG_IGN;
sigaction(signal, &act, NULL);
- last_handler = nit_signals_list[signal].handler;
+ #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) `{
- SignalHandler last_handler;
if (signal < 32 && signal >=0) {
struct sigaction act;
sigemptyset(&act.sa_mask);
act.sa_handler = SIG_DFL;
sigaction(signal, &act, NULL);
- last_handler = nit_signals_list[signal].handler;
+ #ifdef SignalHandler_decr_ref
+ SignalHandler last_handler = (SignalHandler)nit_signals_list[signal].handler;
if (last_handler != NULL)
SignalHandler_decr_ref(last_handler);
+ #endif
}
`}
-
- # 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
-
-
end
redef interface Object
if (nit_signals_list[sig].raised) {
nit_signals_list[sig].raised = 0;
raised_something = 1;
- SignalHandler_receive_signal(nit_signals_list[sig].handler, sig);
+ SignalHandler handler = (SignalHandler)nit_signals_list[sig].handler;
+ SignalHandler_receive_signal(handler, sig);
}
return raised_something;
# can callback any instance of SignalHandler, not just this one
protected fun set_alarm(sec: Int) `{ alarm(sec); `}
end
+
+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
nitlanguage / nit.git / blobdiff