From feeee312bdf5880a6f1d7112212b3e3e892acef4 Mon Sep 17 00:00:00 2001
From: Greg Alexander <gitgreg@galexander.org>
Date: Sun, 16 Oct 2022 23:31:46 -0400
Subject: [PATCH] First draft of API to launch activities

   echo 'activity -- http://buh.com' > api/cmd
---
 .../galexander/sshd/SimpleSSHDService.java    |   2 +
 .../main/java/org/galexander/sshd/api.java    | 104 ++++++++++++++++++
 jni/interface.c                               |  27 +++++
 3 files changed, 133 insertions(+)
 create mode 100644 app/src/main/java/org/galexander/sshd/api.java

diff --git a/app/src/main/java/org/galexander/sshd/SimpleSSHDService.java b/app/src/main/java/org/galexander/sshd/SimpleSSHDService.java
index aba44da..cff39ee 100644
--- a/app/src/main/java/org/galexander/sshd/SimpleSSHDService.java
+++ b/app/src/main/java/org/galexander/sshd/SimpleSSHDService.java
@@ -211,11 +211,13 @@ public class SimpleSSHDService extends Service {
 			int rsyncbuffer, String env, String lib);
 	private static native void kill(int pid);
 	private static native int waitpid(int pid);
+	private static native String api_mkfifo(String path);
 	static {
 		System.loadLibrary("simplesshd-jni");
 	}
 
 	public static void do_startService(Context ctx, boolean stop) {
+		if (!stop) api.start(ctx, api_mkfifo(SimpleSSHD.app_private));
 		Intent i = new Intent(ctx, SimpleSSHDService.class);
 		if (stop) {
 			i.putExtra("stop", true);
diff --git a/app/src/main/java/org/galexander/sshd/api.java b/app/src/main/java/org/galexander/sshd/api.java
new file mode 100644
index 0000000..e76d3f2
--- /dev/null
+++ b/app/src/main/java/org/galexander/sshd/api.java
@@ -0,0 +1,104 @@
+package org.galexander.sshd;
+
+import android.content.Context;
+import android.content.Intent;
+import android.net.Uri;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicReference;
+
+
+public class api {
+	private static AtomicReference<Thread> curr_thread = null;
+
+		/* assumes JNI api_mkfifo() has already completed */
+	public static void start(final Context ctx, final String fn) {
+		if (fn == null) return;
+		if (curr_thread.get() != null) return;
+		Thread t = new Thread() { public void run() {
+						thread_main(ctx, fn); } };
+		if (curr_thread.compareAndSet(null, t)) {
+			t.start();
+		}
+	}
+
+	private static String get_line(FileInputStream fis) throws IOException {
+		byte[] ret = new byte[512];
+		int len = 0;
+		while (true) {
+			if (len+5 > ret.length) {
+				ret = Arrays.copyOf(ret, len+512);
+			}
+			int c = fis.read();
+			if ((c == -1) || (c == '\n') || (c == 0)) {
+				return new String(ret, 0, len);
+			}
+			ret[len++] = (byte)c;
+		}
+	}
+
+	private static String get_command(String fn) {
+		try {
+			FileInputStream fis = new FileInputStream(fn);
+			String ret = get_line(fis);
+			fis.close();
+			return ret;
+		} catch (Exception e) {
+			return null;
+		}
+	}
+
+	private static List<String> split_string(String s) {
+		LinkedList<String> ret = new LinkedList<String>();
+		int ofs = 0;
+		final int len = s.length();
+		while (ofs < len) {
+			while ((ofs < len) &&
+			       Character.isSpace(s.charAt(ofs))) {
+				ofs++;
+			}
+			if (s.startsWith("-- ", ofs)) {
+				ret.add(s.substring(ofs+3));
+				break;
+			} else if (ofs < len) {
+				int start = ofs;
+				while ((ofs < len) &&
+				       !Character.isSpace(s.charAt(ofs))) {
+					ofs++;
+				}
+				ret.add(s.substring(start, ofs-start));
+			}
+		}
+		return ret;
+	}
+
+	private static void parse_command(Context ctx, String s) {
+		List<String> parms = split_string(s);
+		Iterator<String> pi = parms.iterator();
+		String cmd = pi.next();
+
+		if (cmd.equals("activity")) {
+			String url = pi.next();
+			Uri uri = (new Uri.Builder()).path(url).build();
+			ctx.startActivity(new Intent(Intent.ACTION_VIEW, uri));
+		}
+	}
+
+	private static void thread_main(Context ctx, String fn) {
+		int nulls = 0;
+		while (nulls < 5) {		/* retry limit */
+			String s = get_command(fn);
+			if (s == null) {
+				nulls++;
+			} else {
+				nulls = 0;
+				parse_command(ctx, s);
+			}
+		}
+		curr_thread.compareAndSet(Thread.currentThread(), null);
+	}
+}
diff --git a/jni/interface.c b/jni/interface.c
index fd4bfe4..3d42e36 100644
--- a/jni/interface.c
+++ b/jni/interface.c
@@ -2,12 +2,14 @@
 #include <string.h>
 #include <stdio.h>
 #include <jni.h>
+#include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <signal.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <ctype.h>
+#include <errno.h>
 
 const char *conf_path = "", *conf_shell = "", *conf_home = "", *conf_env = "",
 	*conf_lib = "";
@@ -211,3 +213,28 @@ Java_org_galexander_sshd_SimpleSSHDService_waitpid(JNIEnv *env_, jclass cl,
 	}
 	return 0;
 }
+
+
+JNIEXPORT jstring JNICALL
+Java_org_galexander_sshd_SimpleSSHDService_api_1mkfifo(JNIEnv *env_,
+	jobject jpath)
+{
+	if (!jni_init(env_)) {
+		return NULL;
+	}
+
+	const char *path = from_java_string(jpath);
+	char *buf = malloc(strlen(path)+100);
+	sprintf(buf, "%s/api", path);
+	if ((mkdir(buf, 0700) < 0) && (errno != EEXIST)) {
+		perror(buf);
+		return NULL;
+	}
+	sprintf(buf, "%s/api/cmd", path);
+	unlink(buf);
+	if (mkfifo(buf, 0666) < 0) {
+		perror(buf);
+		return NULL;
+	}
+	return (*env)->NewStringUTF(env, buf);
+}