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signal: support the stopping of processes

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Matheus
2024-05-22 13:49:11 -03:00
parent 8e1033f170
commit c3983353b3
1 changed files with 84 additions and 13 deletions
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kernel-src/sys/signal.c
+84 -13
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@@ -139,9 +139,12 @@ void signal_pending(struct thread_t *thread, sigset_t *sigset) {
}
void signal_signalthread(struct thread_t *thread, int signal, bool urgent) {
//bool notignorable = signal == SIGKILL || signal == SIGSTOP || signal == SIGCONT;
PROCESS_ENTER(thread->proc);
THREAD_ENTER(thread);
// TODO kill/stop/continue entire process if default actions call for it etc
sigset_t *sigset = urgent ? &thread->signals.urgent : &thread->signals.pending;
SIGNAL_SETON(sigset, signal);
@@ -162,6 +165,10 @@ void signal_signalproc(struct proc_t *proc, int signal) {
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 notignorable = signal == SIGKILL || signal == SIGSTOP || signal == SIGCONT;
bool threadcontinued = false;
bool isdefaultaction = address == SIG_DFL;
bool shouldstop = (isdefaultaction && defaultactions[signal] == ACTION_STOP) || signal == SIGSTOP;
for (int i = 0; i < proc->threadtablesize; ++i) {
if (proc->threads[i] == NULL || (proc->threads[i]->flags & SCHED_THREAD_FLAGS_DEAD))
@@ -169,28 +176,69 @@ void signal_signalproc(struct proc_t *proc, int signal) {
THREAD_ENTER(proc->threads[i]);
// sigcont will wake up all the threads or unset sigstop as pending
if (signal == SIGCONT) {
// TODO this
} else if (SIGNAL_GET(&proc->threads[i]->signals.mask, signal) == 0 || signal == SIGKILL || signal == SIGSTOP) {
if (SIGNAL_GET(&proc->threads[i]->signals.mask, signal) == 0 || notignorable) {
SIGNAL_SETON(&proc->threads[i]->signals.pending, signal);
if (notignored) {
sched_wakeup(proc->threads[i], SCHED_WAKEUP_REASON_INTERRUPTED);
if (notignored || notignorable) {
int reason = SCHED_WAKEUP_REASON_INTERRUPTED;
if (proc->threads[i]->signals.stopped && (signal == SIGCONT || signal == SIGKILL)) {
// thread is stopped and we have to wake it up
proc->threads[i]->signals.stopped = false;
reason = 0; // wake it up from the non interruptible sleep
threadcontinued = true;
} else if (signal == SIGCONT) {
// thread is not stopped, ignore SIGCONT
SIGNAL_SETOFF(&proc->threads[i]->signals.pending, signal);
goto threadleave;
}
sched_wakeup(proc->threads[i], reason);
// TODO ipi if running isn't self
}
THREAD_LEAVE(proc->threads[i]);
PROCESS_LEAVE(proc);
MUTEX_RELEASE(&proc->mutex);
return;
// if we are stopping or continuing, this will be sent to all individual threads
// XXX possible race condition where a thread will change the process mask or the action of stopping signals
// after it was sent to everyone
if ((shouldstop || signal == SIGCONT) == false) {
THREAD_LEAVE(proc->threads[i]);
PROCESS_LEAVE(proc);
MUTEX_RELEASE(&proc->mutex);
return;
}
}
threadleave:
THREAD_LEAVE(proc->threads[i]);
}
// 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) {
proc->status = 0x7f;
proc->status |= signal << 8;
proc->signals.stopunwaited = true;
if ((proc->parent->signals.actions[SIGCHLD].flags & SA_NOCLDSTOP) == 0) {
signal_signalproc(proc->parent, SIGCHLD);
}
semaphore_signal(&proc->parent->waitsem);
}
// tell the parent that a child continued
if (threadcontinued) {
proc->status = 0xffff;
proc->signals.continueunwaited = true;
if ((proc->parent->signals.actions[SIGCHLD].flags & SA_NOCLDSTOP) == 0) {
signal_signalproc(proc->parent, SIGCHLD);
}
semaphore_signal(&proc->parent->waitsem);
}
MUTEX_RELEASE(&proc->mutex);
// there wasn't any thread with it unmasked, so set it as pending for the whole process
SIGNAL_SETON(&proc->signals.pending, signal);
// if its ignorable and there wasn't any thread with it unmasked, set it as pending for the whole process
// not ignorable signals will be sent to all threads individually
if (notignorable == false && (threadcontinued || shouldstop) == false) {
SIGNAL_SETON(&proc->signals.pending, signal);
}
PROCESS_LEAVE(proc);
}
@@ -200,10 +248,12 @@ bool signal_check(struct thread_t *thread, context_t *context, bool syscall, uin
bool retry = false;
proc_t *proc = thread->proc;
bool intstatus = interrupt_set(false);
PROCESS_ENTER(proc);
THREAD_ENTER(thread);
if (SIGNAL_GET(&proc->signals.pending, SIGKILL) || SIGNAL_GET(&thread->signals.pending, SIGKILL)) {
// TODO terminate entire program
THREAD_LEAVE(thread);
PROCESS_LEAVE(proc);
proc->status = SIGKILL;
@@ -262,12 +312,32 @@ bool signal_check(struct thread_t *thread, context_t *context, bool syscall, uin
goto leave;
case ACTION_CORE:
case ACTION_TERM:
// TODO terminate entire program
proc->status = signal;
THREAD_LEAVE(thread);
PROCESS_LEAVE(proc);
interrupt_set(true);
sched_threadexit();
case ACTION_STOP:
// TODO what if a thread unmasks a stop signal?
// check if sigcont is not pending for the thread (SIGCONT is always sent to the thread)
if (SIGNAL_GET(&thread->signals.pending, SIGCONT)) {
retry = true;
goto leave;
}
// if not, just sleep. the sigcont won't be sent until THREAD_LEAVE and preparesleep is protecting it from a lost wakeup
sched_preparesleep(false);
thread->signals.stopped = true;
THREAD_LEAVE(thread);
PROCESS_LEAVE(proc);
sched_yield();
interrupt_set(intstatus);
// make sure a SIGCONT happened
__assert(SIGNAL_GET(&thread->signals.pending, SIGCONT));
__assert(thread->signals.stopped == false);
// the stopped variable is already set by the signaling function
// see if theres any other signal to deal with (such as the SIGCONT handler)
return true;
default:
__assert(!"unsupported signal action");
}
@@ -335,5 +405,6 @@ bool signal_check(struct thread_t *thread, context_t *context, bool syscall, uin
leave:
THREAD_LEAVE(thread);
PROCESS_LEAVE(proc);
interrupt_set(intstatus);
return retry;
}