* Implemented sigwait().

* Not sure if it works as intended, as the specs are a bit vague.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@24717 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/ksignal.h

@@ -40,6 +40,7 @@ extern status_t _user_sigprocmask(int how, const sigset_t *set,
 extern status_t _user_sigaction(int sig, const struct sigaction *newAction,
 	struct sigaction *oldAction);
 extern bigtime_t _user_set_alarm(bigtime_t time, uint32 mode);
+extern status_t _user_sigwait(const sigset_t *set, int *_signal);
 extern status_t _user_sigsuspend(const sigset_t *mask);
 extern status_t _user_sigpending(sigset_t *set);
 extern status_t _user_set_signal_stack(const stack_t *newUserStack,

headers/private/kernel/syscalls.h

@@ -131,6 +131,7 @@ extern status_t		_kern_sigprocmask(int how, const sigset_t *set,
 extern status_t		_kern_sigaction(int sig, const struct sigaction *action,
 						struct sigaction *oldAction);
 extern bigtime_t	_kern_set_alarm(bigtime_t time, uint32 mode);
+extern status_t		_kern_sigwait(const sigset_t *set, int *_signal);
 extern status_t		_kern_sigsuspend(const sigset_t *mask);
 extern status_t		_kern_sigpending(sigset_t *set);
 extern status_t		_kern_set_signal_stack(const stack_t *newStack,

src/system/kernel/signal.cpp

@@ -7,6 +7,8 @@
 
 /*! POSIX signals handling routines */
 
+#include <ksignal.h>
+
 #include <stddef.h>
 #include <string.h>
 
@@ -17,8 +19,8 @@
 #include <debug.h>
 #include <kernel.h>
 #include <kscheduler.h>
-#include <ksignal.h>
 #include <sem.h>
+#include <syscall_restart.h>
 #include <team.h>
 #include <thread.h>
 #include <tracing.h>
@@ -798,6 +800,46 @@ set_alarm(bigtime_t time, uint32 mode)
 }
 
 
+/*!	Wait for the specified signals, and return the signal retrieved in
+	\a _signal.
+*/
+int
+sigwait(const sigset_t *set, int *_signal)
+{
+	struct thread *thread = thread_get_current_thread();
+	int signalsPending = 0;
+
+	ConditionVariable<sigset_t> conditionVar;
+	conditionVar.Publish(set, "sigwait");
+
+	while (true) {
+		ConditionVariableEntry<sigset_t> entry;
+		entry.Wait(set, B_CAN_INTERRUPT);
+
+		if (has_signals_pending(thread)) {
+			signalsPending = atomic_get(&thread->sig_pending) & *set;
+			break;
+		}
+	}
+
+	conditionVar.Unpublish();
+
+	update_current_thread_signals_flag();
+
+	if (signalsPending) {
+		// select the lowest pending signal to return in _signal
+		for (int signal = 1; signal < NSIG; signal++) {
+			if ((SIGNAL_TO_MASK(signal) & signalsPending) != 0) {
+				*_signal = signal;
+				return B_OK;
+			}
+		}
+	}
+
+	return B_INTERRUPTED;
+}
+
+
 /*!	Replace the current signal block mask and wait for any event to happen.
 	Before returning, the original signal block mask is reinstantiated.
 */
@@ -915,6 +957,25 @@ _user_sigaction(int signal, const struct sigaction *userAction,
 }
 
 
+status_t
+_user_sigwait(const sigset_t *userSet, int *_userSignal)
+{
+	if (userSet == NULL || _userSignal == NULL)
+		return B_BAD_VALUE;
+
+	sigset_t set;
+	if (user_memcpy(&set, userSet, sizeof(sigset_t)) < B_OK)
+		return B_BAD_ADDRESS;
+
+	int signal;
+	status_t status = sigwait(&set, &signal);
+	if (status < B_OK)
+		return syscall_restart_handle_post(status);
+
+	return user_memcpy(_userSignal, &signal, sizeof(int));
+}
+
+
 status_t
 _user_sigsuspend(const sigset_t *userMask)
 {

src/system/libroot/posix/signal/Jamfile

@@ -19,5 +19,6 @@ MergeObject posix_signal.o :
 	sigrelse.cpp
 	sigset.c
 	sigsuspend.c
+	sigwait.c
 	strsignal.c
 ;

src/system/libroot/posix/signal/sigwait.c

@@ -0,0 +1,18 @@
+/*
+ * Copyright 2008, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
+ * Distributed under the terms of the MIT License.
+ */
+
+
+#include <syscalls.h>
+
+#include <signal.h>
+
+
+int
+sigwait(const sigset_t *set, int *_signal)
+{
+	return _kern_sigwait(set, _signal);
+		// does not set errno, but returns the error value directly
+}
+