# 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);
}
}
}
#
# 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) `{
- `}
+ fun receive_signal(signal: Int) do end
# Called immediatly on receiving an unsafe signal (should be redefed by subclasses)
#
#
# 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) `{
- `}
+ 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;
+ 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 = self;
- nit_signals_list[signal].handler = recv;
- SignalHandler_incr_ref(recv);
+ #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
}
`}
end
-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 `{
- 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_receive_signal(nit_signals_list[sig].handler, sig);
- }
+# 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;
- `}
+ return raised_something;
+`}
- # Set alarm signal
- # can callback any instance of SignalHandler, not just this one
- protected fun set_alarm(sec: Int) `{ alarm(sec); `}
-end
+# 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
# 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
-protected fun sighup: Int do return 1
+fun sighup: Int do return 1
# Issued if the user sends an interrupt signal
-protected fun sigint: Int do return 2
+fun sigint: Int do return 2
# Issued if the user sends a quit signal
-protected fun sigquit: Int do return 3
+fun sigquit: Int do return 3
# Issued if the user attempts to execute an illegal, malformed, unknown, or privileged instruction
-protected fun sigill: Int do return 4
+fun sigill: Int do return 4
# Issued when an exception occurs: a condition that a debugger has requested to be informed of
-protected fun sigtrap: Int do return 5
+fun sigtrap: Int do return 5
# This signal is sent to a process to tell it to abort, i. e. to terminate
-protected fun sigabrt: Int do return 6
+fun sigabrt: Int do return 6
# This signal is sent to a process when it causes a bus error
-protected fun sigbus: Int do return 7
+fun sigbus: Int do return 7
# Issued if an illegal mathematical operation is attempted
-protected fun sigfpe: Int do return 8
+fun sigfpe: Int do return 8
# If a process gets this signal it must quit immediately and will not perform any clean-up operations
-protected fun sigkill: Int do return 9
+fun sigkill: Int do return 9
# Sent to a process to indicate user-defined conditions
-protected fun sigusr1: Int do return 10
+fun sigusr1: Int do return 10
# Sent to a process when it makes an invalid virtual memory reference, or segmentation fault
-protected fun sigsegv: Int do return 11
+fun sigsegv: Int do return 11
# Sent to a process to indicate user-defined conditions
-protected fun sigusr2: Int do return 12
+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
-protected fun sigpipe: Int do return 13
+fun sigpipe: Int do return 13
# Alarm Clock signal
-protected fun sigalarm: Int do return 14
+fun sigalarm: Int do return 14
# Software termination signal
-protected fun sigterm: Int do return 15
+fun sigterm: Int do return 15
# Sent to a process when a child process terminates or is interrupted
-protected fun sigchild: Int do return 17
+fun sigchild: Int do return 17
# Tell the operating system to continue (restart) a process previously paused by the SIGSTOP or SIGTSTP signal
-protected fun sigcont: Int do return 18
+fun sigcont: Int do return 18
# Tell the operating system to stop a process
-protected fun sigstop: Int do return 19
+fun sigstop: Int do return 19
# Sent to a process by its terminal to request it to stop temporarily
-protected fun sigtstp: Int do return 20
+fun sigtstp: Int do return 20
# Sent to a process when a socket has urgent or out-of-band data available to read
-protected fun sigurg: Int do return 23
+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
-protected fun sigxcpu: Int do return 24
+fun sigxcpu: Int do return 24
# Sent to a process when it grows a file larger than the maximum allowed size
-protected fun sigxfsz: Int do return 25
+fun sigxfsz: Int do return 25
# Virtual timer expired
-protected fun sigvtalrm: Int do return 26
+fun sigvtalrm: Int do return 26
# Profiling timer expired
-protected fun sigprof: Int do return 27
+fun sigprof: Int do return 27
-# Sent to a process when its controlling terminal changes its window size
-protected fun sigwinch: Int do return 28
+# 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
-protected fun sigpwr: Int do return 30
+fun sigpwr: Int do return 30
# Sent to a process when it passes a bad argument to a system call
-protected fun sigsys: Int do return 31
+fun sigsys: Int do return 31
nitlanguage / nit.git / blobdiff