signal: way to signal all processes

kernel-src/include/kernel/scheduler.h

@@ -166,5 +166,6 @@ void sched_sleepus(size_t us);
 void sched_apentry();
 void sched_inactiveproc(proc_t *proc);
 void sched_terminateprogram(int status);
+int sched_signalall(int signal, proc_t *sender);
 
 #endif

kernel-src/sys/scheduler.c

@@ -12,6 +12,7 @@
 #include <kernel/devfs.h>
 #include <kernel/jobctl.h>
 #include <kernel/cmdline.h>
+#include <kernel/auth.h>
 
 #define QUANTUM_US 100000
 #define SCHEDULER_STACK_SIZE PAGE_SIZE * 16
@@ -49,6 +50,30 @@ proc_t *sched_getprocfrompid(int pid) {
 	return proc;
 }
 
+int sched_signalall(int signal, proc_t *sender) {
+	MUTEX_ACQUIRE(&sched_pidtablemutex, false);
+
+	pid_t senderpgid = sender ? jobctl_getpgid(sender) : 0;
+
+	size_t donecount = 0;
+	HASHTABLE_FOREACH(&pidtable) {
+		proc_t *current = entry->value;
+		// init does not get signaled
+		if (current->pid == 1)
+			continue;
+
+		pid_t currentpgid = jobctl_getpgid(current);
+
+		if (senderpgid == 0 || (signal == SIGCONT && currentpgid == senderpgid) || auth_process_check(&sender->cred, AUTH_ACTIONS_PROCESS_SIGNAL, current)) {
+			++donecount;
+			signal_signalproc(current, signal);
+		}
+	}
+
+	MUTEX_RELEASE(&sched_pidtablemutex);
+	return donecount == 0 ? EPERM : 0;
+}
+
 static void rtdpc(context_t *, dpcarg_t arg) {
 	signal_signalproc(arg, SIGALRM);
 }

kernel-src/sys/syscalls/kill.c

@@ -19,14 +19,9 @@ syscallret_t syscall_kill(context_t *context, int pid, int signal) {
 		effectivepid = -1;
 	else if (pid < -1)
 		effectivepid = -pid; // target specific process group
-	
-	if (effectivepid == -1) {
-		ret.errno = ESRCH;
-		return ret;
-	}
 
 	proc_t *target = sched_getprocfrompid(effectivepid);
-	if (target == NULL && pid != 0) {
+	if (target == NULL && pid != 0 && pid != -1) {
 		ret.errno = ESRCH;
 		return ret;
 	}
@@ -43,6 +38,8 @@ syscallret_t syscall_kill(context_t *context, int pid, int signal) {
 		}
 
 		signal_signalproc(target, signal);
+	} else if (pid == -1) {
+		ret.errno = sched_signalall(signal, _cpu()->thread->proc);
 	} else {
 		ret.errno = jobctl_signal(target, signal, _cpu()->thread->proc);
 	}