initial signal implementation

kernel-src/sys/syscalls/kill.c

@@ -0,0 +1,40 @@
+#include <kernel/syscalls.h>
+#include <arch/cpu.h>
+#include <logging.h>
+
+syscallret_t syscall_kill(context_t *context, int pid, int signal) {
+	syscallret_t ret = {
+		.ret = -1
+	};
+
+	int effectivepid = -1;
+
+	if (pid > 0) // specific process
+		effectivepid = pid;
+	else if (pid == 0) // own process group
+		effectivepid = 0;
+	else if (pid == -1) // every process, unsupported atm
+		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(pid);
+	if (target == NULL && pid != 0) {
+		ret.errno = ESRCH;
+		return ret;
+	}
+
+	if (pid >= 1)
+		signal_signalproc(target, signal);
+	else
+		ret.errno = jobctl_signal(target, signal);
+
+	ret.errno = 0;
+	ret.ret = 0;
+	return ret;
+}