X-Git-Url: http://nitlanguage.org diff --git a/lib/signals.nit b/lib/signals.nit index c4bb84b..440fd39 100644 --- a/lib/signals.nit +++ b/lib/signals.nit @@ -14,7 +14,49 @@ # 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 `{ @@ -22,6 +64,11 @@ module signals #define _POSIX_SOURCE 1 #include #include + #include + + /* + */ + void (*nit_SignalHandler_receive_signal)(void* self, long signal); /* Structure to manage each possible signals @@ -30,9 +77,9 @@ module 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, @@ -45,7 +92,7 @@ module signals 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); } } } @@ -53,21 +100,48 @@ module signals # 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); @@ -76,20 +150,26 @@ interface SignalHandler 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); @@ -97,15 +177,16 @@ interface SignalHandler 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); @@ -113,22 +194,13 @@ interface SignalHandler 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 } `} - - fun sigalarm: Int do return 14 - fun sighup: Int do return 1 - fun sigint: Int do return 2 - fun sigkill: Int do return 9 - fun sigpipe: Int do return 13 - fun sigterm: Int do return 15 - fun sigabrt: Int do return 6 - fun sigfpe: Int do return 8 - fun sigquit: Int do return 3 - fun sigsegv: Int do return 11 end redef interface Object @@ -136,7 +208,7 @@ redef interface Object # Check signals for safe operation # will callback receiver of raised signals # can callback any instance of SignalHandler, not just this one - protected fun check_signals: Bool is extern import SignalHandler::receive_signal `{ + protected fun check_signals: Bool is extern import SignalHandler.receive_signal `{ int sig; int raised_something = 0; @@ -144,7 +216,8 @@ 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; @@ -154,3 +227,95 @@ redef interface Object # 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