add kill app

userspace/core/kill.c

@@ -0,0 +1,50 @@
+/*
+ * kill
+ *
+ * Send a signal to another process
+ */
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <signal.h>
+
+void usage(char * argv[]) {
+	printf(
+			"kill - send a signal to another process\n"
+			"\n"
+			"usage: %s [-\033[3mx\033[0m] \033[3mprocess\033[0m\n"
+			"\n"
+			" -h --help       \033[3mShow this help message.\033[0m\n"
+			" -\033[3mx\033[0m              \033[3mSignal number to send\033[0m\n"
+			"\n",
+			argv[0]);
+}
+
+int main(int argc, char * argv[]) {
+	int signum = SIGKILL;
+	int pid = 0;
+
+	if (argc < 2) {
+		usage(argv);
+		return 1;
+	}
+
+	if (argc > 2) {
+		if (argv[1][0] == '-') {
+			signum = atoi(argv[1]+1);
+		} else {
+			usage(argv);
+			return 1;
+		}
+		pid = atoi(argv[2]);
+	} else if (argc == 2) {
+		pid = atoi(argv[1]);
+	}
+
+	if (pid) {
+		kill(pid, signum);
+	}
+
+	return 0;
+}