signal: check for pending signals before yield

README.md

@@ -10,7 +10,7 @@ Astral is a 64 bit operating system with its own kernel written in C for the x86
 - SMP capable preemptible kernel
 - Networking (UDP, DHCP)
 - POSIX compatibility
-- Ports: mlibc, X.org, gcc, bash, doom, quake, vim, nano and more
+- Ports: X.org, fvwm3, gcc, bash, quake, vim and more
 - Filesystems: tmpfs, devfs, ext2
 - Block devices: NVMe, virtio-block
 - Network devices: virtio-net
@@ -18,6 +18,8 @@ Astral is a 64 bit operating system with its own kernel written in C for the x86
 ## Current Goals
 
 - TCP
+- Fat32
+- Disk Caching
 
 ## Building
 

kernel-src/include/kernel/signal.h

@@ -144,6 +144,12 @@ typedef struct {
 #define SIG_UNBLOCK 1
 #define SIG_SETMASK 2
 
+#define SIG_ACTION_TERM 0
+#define SIG_ACTION_IGN 1
+#define SIG_ACTION_CORE 2
+#define SIG_ACTION_STOP 3
+#define SIG_ACTION_CONT 4
+
 struct proc_t;
 struct thread_t;
 void signal_action(struct proc_t *proc, int signal, sigaction_t *new, sigaction_t *old);
@@ -153,5 +159,6 @@ void signal_signalproc(struct proc_t *proc, int signal);
 void signal_signalthread(struct thread_t *thread, int signal, bool urgent);
 void signal_pending(struct thread_t *, sigset_t *sigset);
 bool signal_check(struct thread_t *thread, context_t *context, bool syscall, uint64_t syscallret, uint64_t syscallerrno);
+extern int signal_defaultactions[NSIG];
 
 #endif

kernel-src/sys/scheduler.c

@@ -429,7 +429,23 @@ static void yield(context_t *context) {
 
 	thread_t *next = runqueuenext(sleeping ? 0x0fffffff : thread->priority);
 
-	if (sleeping && thread->shouldexit && (thread->flags & SCHED_THREAD_FLAGS_INTERRUPTIBLE)) {
+	bool gotsignal = false;
+	for (int i = 0; i < NSIG && thread->proc; ++i) {
+		void *action = thread->proc->signals.actions[i].address;
+		if (SIGNAL_GET(&thread->signals.urgent, i)) {
+			gotsignal = true;
+			break;
+		}
+		if (action == SIG_IGN || (action == SIG_DFL && signal_defaultactions[i] == SIG_ACTION_IGN) || SIGNAL_GET(&thread->signals.mask, i))
+			continue;
+
+		if (SIGNAL_GET(&thread->signals.pending, i) || SIGNAL_GET(&thread->proc->signals.pending, i)) {
+			gotsignal = true;
+			break;
+		}
+	}
+
+	if (sleeping && (thread->shouldexit || gotsignal) && (thread->flags & SCHED_THREAD_FLAGS_INTERRUPTIBLE)) {
 		sleeping = false;
 		next = NULL;
 		thread->flags &= ~(SCHED_THREAD_FLAGS_SLEEP | SCHED_THREAD_FLAGS_INTERRUPTIBLE);

kernel-src/sys/signal.c

@@ -8,7 +8,7 @@
 #define ACTION_STOP 3
 #define ACTION_CONT 4
 
-static int defaultactions[NSIG] = {
+int signal_defaultactions[NSIG] = {
 	[SIGABRT] = ACTION_CORE,
 	[SIGALRM] = ACTION_TERM,
 	[SIGBUS] = ACTION_CORE,
@@ -149,7 +149,7 @@ void signal_signalthread(struct thread_t *thread, int signal, bool urgent) {
 	SIGNAL_SETON(sigset, signal);
 
 	void *address = thread->proc->signals.actions[signal].address;
-	bool notignored = address != SIG_IGN && ((address == SIG_DFL && defaultactions[signal] != ACTION_IGN) || address != SIG_DFL);
+	bool notignored = address != SIG_IGN && ((address == SIG_DFL && signal_defaultactions[signal] != ACTION_IGN) || address != SIG_DFL);
 
 	if (signal == SIGKILL || signal == SIGSTOP || urgent || (SIGNAL_GET(&thread->signals.mask, signal) == 0 && notignored)) {
 		sched_wakeup(thread, SCHED_WAKEUP_REASON_INTERRUPTED);
@@ -164,11 +164,13 @@ void signal_signalproc(struct proc_t *proc, int signal) {
 	MUTEX_ACQUIRE(&proc->mutex, false);
 	PROCESS_ENTER(proc);
 	void *address = proc->signals.actions[signal].address;
-	bool notignored = address != SIG_IGN && ((address == SIG_DFL && defaultactions[signal] != ACTION_IGN) || address != SIG_DFL);
+	bool notignored = address != SIG_IGN && ((address == SIG_DFL && signal_defaultactions[signal] != ACTION_IGN) || address != SIG_DFL);
 	bool notignorable = signal == SIGKILL || signal == SIGSTOP || signal == SIGCONT;
 	bool threadcontinued = false;
 	bool isdefaultaction = address == SIG_DFL;
-	bool shouldstop = (isdefaultaction && defaultactions[signal] == ACTION_STOP) || signal == SIGSTOP;
+	bool shouldstop = (isdefaultaction && signal_defaultactions[signal] == ACTION_STOP) || signal == SIGSTOP;
+
+	// TODO is one thread has a stop signal masked, the masked wait breaks completely
 
 	for (int i = 0; i < proc->threadtablesize; ++i) {
 		if (proc->threads[i] == NULL || (proc->threads[i]->flags & SCHED_THREAD_FLAGS_DEAD))
@@ -212,7 +214,7 @@ void signal_signalproc(struct proc_t *proc, int signal) {
 
 	// tell the parent that a child stopped
 	// TODO when stopping make sure that a thread was actually stopped
-	if ((notignorable || notignored) && defaultactions[signal] == ACTION_STOP) {
+	if ((notignorable || notignored) && signal_defaultactions[signal] == ACTION_STOP) {
 		proc->status = 0x7f;
 		proc->status |= signal << 8;
 		proc->signals.stopunwaited = true;
@@ -302,7 +304,7 @@ bool signal_check(struct thread_t *thread, context_t *context, bool syscall, uin
 		goto leave;
 	} else if ((action->address == SIG_DFL && (action->flags & SA_SIGINFO) == 0) || (action->address == SIG_IGN && sigset == &thread->signals.urgent)) {
 		// default action
-		int defaction = defaultactions[signal];
+		int defaction = signal_defaultactions[signal];
 		switch (defaction) {
 			case ACTION_IGN:
 			case ACTION_CONT: