WHC Shell: keyboard-first Android terminal over SSH to local Termux

Vendored Termux terminal-emulator/renderer (Apache 2.0) with kitty keyboard protocol, modifyOtherKeys and any-event mouse tracking; sshj client with Ed25519 key login and TOFU host keys; Termux font/colors/cursor sync; mouse selection, context menu, zoom and fullscreen shortcuts.
2026-10-06 01:51:31 +08:00
commit a0023fd2ae
37 changed files with 7840 additions and 0 deletions
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+package xyz.whcself.whcshell;
+
+import org.bouncycastle.crypto.AsymmetricCipherKeyPair;
+import org.bouncycastle.crypto.generators.Ed25519KeyPairGenerator;
+import org.bouncycastle.crypto.params.Ed25519KeyGenerationParameters;
+import org.bouncycastle.crypto.util.OpenSSHPrivateKeyUtil;
+import org.bouncycastle.crypto.util.OpenSSHPublicKeyUtil;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.security.SecureRandom;
+import java.util.Base64;
+
+/** The client's Ed25519 identity, stored in OpenSSH format in a private directory. */
+final class SshKeys {
+
+    final File privateKey;
+    final File publicKey;
+
+    private SshKeys(File dir) {
+        privateKey = new File(dir, "id_ed25519");
+        publicKey = new File(dir, "id_ed25519.pub");
+    }
+
+    /** Loads the key pair from {@code dir}, generating it first if missing. */
+    static SshKeys ensure(File dir, String comment) throws IOException {
+        SshKeys k = new SshKeys(dir);
+        if (k.privateKey.isFile() && k.publicKey.isFile()) return k;
+        if (!dir.isDirectory() && !dir.mkdirs()) throw new IOException("cannot create " + dir);
+
+        Ed25519KeyPairGenerator gen = new Ed25519KeyPairGenerator();
+        gen.init(new Ed25519KeyGenerationParameters(new SecureRandom()));
+        AsymmetricCipherKeyPair pair = gen.generateKeyPair();
+
+        Base64.Encoder b64 = Base64.getEncoder();
+        String priv = "-----BEGIN OPENSSH PRIVATE KEY-----\n"
+            + Base64.getMimeEncoder(70, new byte[]{'\n'}).encodeToString(
+                OpenSSHPrivateKeyUtil.encodePrivateKey(pair.getPrivate()))
+            + "\n-----END OPENSSH PRIVATE KEY-----\n";
+        String pub = "ssh-ed25519 "
+            + b64.encodeToString(OpenSSHPublicKeyUtil.encodePublicKey(pair.getPublic()))
+            + " " + comment.replaceAll("[^A-Za-z0-9._@-]", "_") + "\n";
+
+        write(k.privateKey, priv);
+        write(k.publicKey, pub);
+        return k;
+    }
+
+    /** The single authorized_keys line, without a trailing newline. */
+    String publicLine() throws IOException {
+        return new String(Files.readAllBytes(publicKey.toPath()), StandardCharsets.UTF_8).trim();
+    }
+
+    private static void write(File f, String s) throws IOException {
+        File tmp = new File(f.getPath() + ".tmp");
+        try (FileOutputStream out = new FileOutputStream(tmp)) {
+            out.write(s.getBytes(StandardCharsets.UTF_8));
+            out.getFD().sync();
+        }
+        tmp.setReadable(false, false);
+        tmp.setReadable(true, true);
+        tmp.setWritable(false, false);
+        tmp.setWritable(true, true);
+        if (!tmp.renameTo(f)) throw new IOException("cannot rename " + tmp);
+    }
+}