first draft of rough JNI interface

jni/interface.c

@@ -1,4 +1,65 @@
+#include <jni.h>
+#include <sys/types.h>
+#include <signal.h>
+#include <unistd.h>
 
-/* XXX - java-invocable function that starts listener */
 /* XXX - do i need a function to generate host keys? DROPBEAR_DELAY_HOSTKEY */
 /* XXX - a C-callable interface to get property strings from the java side (paths, etc) */
+
+static JNIEnv *env;
+static jclass cl_string;
+static jclass cl_simplesshdservice;
+static jfieldID fid_sss_sshd_pid;
+
+static int
+jni_init(JNIEnv *env_)
+{
+	env = env_;
+#define CLASS(var, id) \
+	cl_##var = (*env)->FindClass(env, id); \
+	if (!cl_##var) return 0;
+#define METHOD(var, mycl, id, sig) \
+	mid_##var = (*env)->GetMethodID(env, cl_##mycl, id, sig); \
+	if (!mid_##var) return 0;
+#define FIELD(var, mycl, id, sig) \
+	fid_##var = (*env)->GetFieldID(env, cl_##mycl, id, sig); \
+	if (!fid_##var) return 0;
+#define STFIELD(var, mycl, id, sig) \
+	fid_##var = (*env)->GetStaticFieldID(env, cl_##mycl, id, sig); \
+	if (!fid_##var) return 0;
+
+	CLASS(string, "java/lang/String")
+	CLASS(simplesshdservice, "org/galexander/sshd/SimpleSSHDService")
+
+	FIELD(sss_sshd_pid, simplesshdservice, "sshd_pid", "I")
+
+	return 1;
+}
+
+JNIEXPORT void JNICALL
+Java_org_galexander_sshd_SimpleSSHDService_start_1sshd(JNIEnv *env_,
+	jobject this)
+{
+	pid_t pid;
+	if (!jni_init(env_)) {
+		return;
+	}
+	pid = fork();
+	if (pid == 0) {
+		/* XXX - call dropbear main() */
+	} else {
+		(*env)->SetIntField(env, this, fid_sss_sshd_pid, pid);
+	}
+}
+
+JNIEXPORT void JNICALL
+Java_org_galexander_sshd_SimpleSSHDService_stop_1sshd(JNIEnv *env_, jobject this)
+{
+	pid_t pid;
+	if (!jni_init(env_)) {
+		return;
+	}
+	pid = (*env)->GetIntField(env, this, fid_sss_sshd_pid);
+	kill(pid, SIGKILL);
+	(*env)->SetIntField(env, this, fid_sss_sshd_pid, 0);
+}