Add implementation of omrsig_set_single_async_signal_handler [Unix]

Added Unix implementation of omrsig_set_single_async_signal_handler in
omrsignal.c.

Added a new macro OMR_IS_ONLY_ONE_BIT_SET in omrcomp.h to check if only
one bit is set in a non-zero value.

Signed-off-by: Babneet Singh <sbabneet@ca.ibm.com>

include_core/omrcomp.h

@@ -575,6 +575,7 @@ typedef struct U_128 {
 #define OMR_ARE_ANY_BITS_SET(value, bits) (0 != ((value) & (bits)))
 #define OMR_ARE_ALL_BITS_SET(value, bits) ((bits) == ((value) & (bits)))
 #define OMR_ARE_NO_BITS_SET(value, bits) (!OMR_ARE_ANY_BITS_SET(value, bits))
+#define OMR_IS_ONLY_ONE_BIT_SET(value) (0 == (value & (value - 1)))
 
 /* Workaround for gcc -Wunused-result, which was added in 4.5.4 */
 #if defined(__GNUC__) && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 5)))

port/common/omrport.tdf

@@ -1053,4 +1053,14 @@ TraceEvent=Trc_PRT_sysinfo_cgroup_get_memlimit_unlimited Group=sysinfo Overhead=
 TraceEvent=Trc_PRT_sysinfo_cgroup_get_memlimit Group=sysinfo Overhead=1 Level=1 NoEnv Template="omrsysinfo_cgroup_get_memlimit: memory limit is 0x%llx bytes" 
 TraceExit=Trc_PRT_sysinfo_cgroup_get_memlimit_Exit Group=sysinfo Overhead=1 Level=3 NoEnv Template="omrsysinfo_cgroup_get_memlimit exiting with rc=%d"
 
-TraceEvent=Trc_PRT_signal_registerSignalHandlerWithOS_registeredHandler1 Group=signal Overhead=1 Level=1 NoEnv Template="registerSignalHandlerWithOS, registered signal handler with OS, portLibrarySignalNo=0x%X, unixSignalNo=0x%X, handler=%p, oldOSHandler=%p" 
+TraceEvent=Trc_PRT_signal_registerSignalHandlerWithOS_registeredHandler1 Group=signal Overhead=1 Level=1 NoEnv Template="registerSignalHandlerWithOS, registered signal handler with OS, portLibrarySignalNo=0x%X, unixSignalNo=0x%X, handler=%p, oldOSHandler=%p"
+
+TraceEntry=Trc_PRT_signal_omrsig_set_single_async_signal_handler_entered Group=signal Overhead=1 Level=1 NoEnv Template="omrsig_set_single_async_signal_handler: Entered, handler=%p, handler_arg=%p, portlibSignalFlag=0x%X"
+TraceExit-Exception=Trc_PRT_signal_omrsig_set_single_async_signal_handler_error_multiple_signal_flags_found Group=signal Overhead=1 Level=1 NoEnv Template="omrsig_set_single_async_signal_handler: Exiting, error: more than one signal bit set in portlibSignalFlag=0x%X"
+TraceEvent=Trc_PRT_signal_omrsig_set_single_async_signal_handler_will_not_set_handler_due_to_Xrs Group=signal Overhead=1 Level=1 NoEnv Template="omrsig_set_single_async_signal_handler: will not set handler due to Xrs, handler=%p, handler_arg=%p, portlibSignalFlag=0x%X"
+TraceExit-Exception=Trc_PRT_signal_omrsig_set_single_async_signal_handler_exiting_did_nothing_possible_error Group=signal Overhead=1 Level=1 NoEnv Template="omrsig_set_single_async_signal_handler: Exiting, possible error, rc=%d, handler=%p, handler_arg=%p, portlibSignalFlag=0x%X"
+TraceEvent=Trc_PRT_signal_omrsig_set_single_async_signal_handler_user_handler_removed Group=signal Overhead=1 Level=1 NoEnv Template="omrsig_set_single_async_signal_handler: user handler removed, handler=%p, handler_arg=%p, portlibSignalFlag=0x%X"
+TraceEvent=Trc_PRT_signal_omrsig_set_single_async_signal_handler_user_handler_added_1 Group=signal Overhead=1 Level=1 NoEnv Template="omrsig_set_single_async_signal_handler: user handler added_1, handler=%p, handler_arg=%p, portlibSignalFlag=0x%X"
+TraceEvent=Trc_PRT_signal_omrsig_set_single_async_signal_handler_user_handler_added_2 Group=signal Overhead=1 Level=1 NoEnv Template="omrsig_set_single_async_signal_handler: user handler added_2, handler=%p, handler_arg=%p, portlibSignalFlag=0x%X"
+TraceExit=Trc_PRT_signal_omrsig_set_single_async_signal_handler_exiting Group=signal Overhead=1 Level=1 NoEnv Template="omrsig_set_single_async_signal_handler: Exiting, rc=%d, handler=%p, handler_arg=%p, portlibSignalFlag=0x%X, oldOSHandler=%p"
+

port/common/omrsignal.c

@@ -174,13 +174,19 @@ omrsig_set_async_signal_handler(struct OMRPortLibrary *portLibrary, omrsig_handl
 
 /*
  * @brief Similar to omrsig_set_async_signal_handler. Refer to omrsig_set_async_signal_handler's description above.
- * Differences: 1) one omrsig_handler_fn handler is registered with a signal at any time instead of multiple handlers.
- * 2) The address to the old signal handler function is stored in oldOSHandler.
+ * A new element is added to the asyncHandlerList for omrsig_handler_fn, and masterASynchSignalHandler is registered
+ * with the OS for the signal corresponding to the specified portlibSignalFlag. masterASynchSignalHandler invokes
+ * asyncHandlerList elements when a relevant signal is raised. If portlibSignalFlag is 0, then the asyncHandlerList
+ * entry corresponding to omrsig_handler_fn is removed, and related resources are freed. portlibSignalFlag can only
+ * have one signal flag set; otherwise, OMRPORT_SIG_ERROR is returned. One omrsig_handler_fn handler is registered
+ * with a signal at any time instead of multiple handlers. When associating a new omrsig_handler_fn with a signal,
+ * prior omrsig_handler_fn(s) are dissociated from the signal. The address of the old signal handler function is
+ * stored in oldOSHandler. This function supports all signals listed in OMRPORT_SIG_FLAG_SIGALLASYNC.
  *
  * @param[in] portLibrary The port library
  * @param[in] handler the function to call if an asynchronous signal arrives
  * @param[in] handler_arg the argument to handler
- * @param[in] portlibSignalFlag port library signal flag
+ * @param[in] portlibSignalFlag a single port library signal flag, or 0 to remove the omrsig_handler_fn entry
  * @param[out] oldOSHandler points to the old signal handler function
  *
  * @return 0 on success or non-zero on failure

port/unix/omrsignal.c

@@ -483,7 +483,99 @@ omrsig_set_async_signal_handler(struct OMRPortLibrary *portLibrary, omrsig_handl
 int32_t
 omrsig_set_single_async_signal_handler(struct OMRPortLibrary *portLibrary, omrsig_handler_fn handler, void *handler_arg, uint32_t portlibSignalFlag, void **oldOSHandler)
 {
-	return OMRPORT_SIG_ERROR;
+	uint32_t rc = 0;
+	J9UnixAsyncHandlerRecord *cursor = NULL;
+	J9UnixAsyncHandlerRecord **previousLink = NULL;
+	BOOLEAN foundHandler = FALSE;
+
+	Trc_PRT_signal_omrsig_set_single_async_signal_handler_entered(handler, handler_arg, portlibSignalFlag);
+
+	if (0 != portlibSignalFlag) {
+		/* For non-zero portlibSignalFlag, check if only one signal bit is set. Otherwise, fail. */
+		if (!OMR_IS_ONLY_ONE_BIT_SET(portlibSignalFlag)) {
+			Trc_PRT_signal_omrsig_set_single_async_signal_handler_error_multiple_signal_flags_found(portlibSignalFlag);
+			return OMRPORT_SIG_ERROR;
+		}
+	}
+
+	omrthread_monitor_enter(masterHandlerMonitor);
+
+	if (OMR_ARE_ANY_BITS_SET(signalOptionsGlobal, OMRPORT_SIG_OPTIONS_REDUCED_SIGNALS_ASYNCHRONOUS)) {
+		/* -Xrs was set, we can't protect against any signals, do not install any handlers except SIGXFSZ*/
+		if (OMR_ARE_ANY_BITS_SET(portlibSignalFlag, OMRPORT_SIG_FLAG_SIGXFSZ) && OMR_ARE_ANY_BITS_SET(signalOptionsGlobal, OMRPORT_SIG_OPTIONS_SIGXFSZ)) {
+			rc = registerMasterHandlers(portLibrary, OMRPORT_SIG_FLAG_SIGXFSZ, OMRPORT_SIG_FLAG_SIGALLASYNC, oldOSHandler);
+		} else {
+			Trc_PRT_signal_omrsig_set_single_async_signal_handler_will_not_set_handler_due_to_Xrs(handler, handler_arg, portlibSignalFlag);
+			rc = OMRPORT_SIG_ERROR;
+		}
+	} else {
+		rc = registerMasterHandlers(portLibrary, portlibSignalFlag, OMRPORT_SIG_FLAG_SIGALLASYNC, oldOSHandler);
+	}
+	omrthread_monitor_exit(masterHandlerMonitor);
+
+	if (0 != rc) {
+		Trc_PRT_signal_omrsig_set_single_async_signal_handler_exiting_did_nothing_possible_error(rc, handler, handler_arg, portlibSignalFlag);
+		return rc;
+	}
+
+	omrthread_monitor_enter(asyncMonitor);
+
+	/* wait until no signals are being reported */
+	while (asyncThreadCount > 0) {
+		omrthread_monitor_wait(asyncMonitor);
+	}
+
+	/* is this handler already registered? */
+	previousLink = &asyncHandlerList;
+	cursor = asyncHandlerList;
+
+	while (NULL != cursor) {
+		if (cursor->portLib == portLibrary) {
+			if ((cursor->handler == handler) && (cursor->handler_arg == handler_arg)) {
+				foundHandler = TRUE;
+				if (0 == portlibSignalFlag) {
+					/* Remove the listener. Remove this handler record.
+					 * NOTE: masterHandlers get removed at omrsignal shutdown
+					 */
+					*previousLink = cursor->next;
+					portLibrary->mem_free_memory(portLibrary, cursor);
+					Trc_PRT_signal_omrsig_set_single_async_signal_handler_user_handler_removed(handler, handler_arg, portlibSignalFlag);
+					break;
+				} else {
+					/* Update the listener with the new portlibSignalFlag */
+					Trc_PRT_signal_omrsig_set_single_async_signal_handler_user_handler_added_1(handler, handler_arg, portlibSignalFlag);
+					cursor->flags |= portlibSignalFlag;
+				}
+			} else {
+				/* Unset the portlibSignalFlag for other handlers. One signal must be associated to only one handler. */
+				cursor->flags &= ~portlibSignalFlag;
+			}
+		}
+		previousLink = &cursor->next;
+		cursor = cursor->next;
+	}
+
+	if (!foundHandler && (0 != portlibSignalFlag)) {
+		J9UnixAsyncHandlerRecord *record = portLibrary->mem_allocate_memory(portLibrary, sizeof(*record), OMR_GET_CALLSITE(), OMRMEM_CATEGORY_PORT_LIBRARY);
+		if (NULL == record) {
+			rc = 1;
+		} else {
+			record->portLib = portLibrary;
+			record->handler = handler;
+			record->handler_arg = handler_arg;
+			record->flags = portlibSignalFlag;
+			record->next = NULL;
+
+			/* add the new record to the end of the list */
+			Trc_PRT_signal_omrsig_set_single_async_signal_handler_user_handler_added_2(handler, handler_arg, portlibSignalFlag);
+			*previousLink = record;
+		}
+	}
+
+	omrthread_monitor_exit(asyncMonitor);
+
+	Trc_PRT_signal_omrsig_set_single_async_signal_handler_exiting(rc, handler, handler_arg, portlibSignalFlag, *oldOSHandler);
+	return rc;
 }
 
 uint32_t