Support for legacy script (#1)

.github/workflows/build.yml

@@ -50,7 +50,7 @@ jobs:
         run: zip -ry StikJIT.xcframework.zip StikJIT.xcframework
 
       - name: Upload artifact
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v7
         with:
           name: StikJIT.xcframework
           path: StikJIT.xcframework.zip

README.md

@@ -2,7 +2,7 @@
 
 An iOS XCFramework that enables JIT for another process over the device's RSD tunnel.
 
-JIT cannot be enabled in-process, since a process that attaches a debugger to itself deadlocks. StikJIT runs in a separate process, attaches a debugserver to the target by PID, enables JIT for it, then detaches. It is self-contained: the idevice FFI and `universal.js` are bundled inside. The target must have the `get-task-allow` entitlement.
+JIT cannot be enabled in-process, since a process that attaches a debugger to itself deadlocks. StikJIT runs in a separate process, attaches a debugserver to the target by PID, enables JIT for it, then detaches. It is self-contained: the idevice FFI and its bundled JIT scripts (`universal.js`, `legacy.js`) are bundled inside. The target must have the `get-task-allow` entitlement.
 
 ## Use
 
@@ -20,7 +20,7 @@ try StikJIT.enableJIT(
 )
 ```
 
-It blocks until done and throws `StikJITError` on failure. Pass `configuration:` to override the tunnel endpoint (defaults to `10.7.0.1:49152`).
+It blocks until done and throws `StikJITError` on failure. Pass `configuration:` to override the tunnel endpoint (defaults to `10.7.0.1:49152`). Pass `script:` to select the bundled JS used to drive the JIT-enabling exchange on devices with TXM — `.universal` (default) or `.legacy` based on your app's needs.
 
 ## Build
 
@@ -35,4 +35,4 @@ xcodebuild -create-xcframework \
 
 ## License
 
-StikJIT is licensed under the MPL-2.0 (see [`LICENSE`](LICENSE)). It uses StikDebug as a reference, with the bundled [idevice](https://github.com/jkcoxson/idevice) and universal.js retaining their own licenses.
+StikJIT is licensed under the MPL-2.0 (see [`LICENSE`](LICENSE)). It uses StikDebug as a reference, with the bundled [idevice](https://github.com/jkcoxson/idevice), universal.js, and legacy.js retaining their own licenses.

Resources/legacy.js

@@ -0,0 +1,98 @@
+function littleEndianHexStringToNumber(hexStr) {
+    const bytes = [];
+    for (let i = 0; i < hexStr.length; i += 2) {
+        bytes.push(parseInt(hexStr.substr(i, 2), 16));
+    }
+    let num = 0n;
+    for (let i = 4; i >= 0; i--) {
+        num = (num << 8n) | BigInt(bytes[i]);
+    }
+    return num;
+}
+
+function numberToLittleEndianHexString(num) {
+    const bytes = [];
+    for (let i = 0; i < 5; i++) {
+        bytes.push(Number(num & 0xFFn));
+        num >>= 8n;
+    }
+    while (bytes.length < 8) {
+        bytes.push(0);
+    }
+    return bytes.map(b => b.toString(16).padStart(2, '0')).join('');
+}
+
+function littleEndianHexToU32(hexStr) {
+    return parseInt(hexStr.match(/../g).reverse().join(''), 16);
+}
+
+function extractBrkImmediate(u32) {
+    return (u32 >> 5) & 0xFFFF;
+}
+
+function attach(breakpointcount) {
+    let pid = get_pid();
+    log(`pid = ${pid}`);
+    let attachResponse = send_command(`vAttach;${pid.toString(16)}`);
+    log(`attach_response = ${attachResponse}`);
+    
+    let validBreakpoints = 0;
+    let totalBreakpoints = 0;
+
+    while (validBreakpoints < breakpointcount) {
+        totalBreakpoints++;
+        log(`Handling breakpoint ${totalBreakpoints} (looking for valid breakpoint ${validBreakpoints + 1}/${breakpointcount})`);
+        
+        let brkResponse = send_command(`c`);
+        log(`brkResponse = ${brkResponse}`);
+        
+        let tidMatch = /T[0-9a-f]+thread:(?<tid>[0-9a-f]+);/.exec(brkResponse);
+        let tid = tidMatch ? tidMatch.groups['tid'] : null;
+        let pcMatch = /20:(?<reg>[0-9a-f]{16});/.exec(brkResponse);
+        let pc = pcMatch ? pcMatch.groups['reg'] : null;
+        let x0Match = /00:(?<reg>[0-9a-f]{16});/.exec(brkResponse);
+        let x0 = x0Match ? x0Match.groups['reg'] : null;
+        let x1Match = /01:(?<reg>[0-9a-f]{16});/.exec(brkResponse);
+        let x1 = x1Match ? x1Match.groups['reg'] : null;
+        
+        if (!tid || !pc || !x0 || !x1) {
+            log(`Failed to extract registers: tid=${tid}, pc=${pc}, x0=${x0}, x1=${x1}`);
+            continue;
+        }
+        
+        const pcNum = littleEndianHexStringToNumber(pc);
+        const x0Num = littleEndianHexStringToNumber(x0);
+        const x1Num = littleEndianHexStringToNumber(x1);
+        log(`tid = ${tid}, pc = ${pcNum.toString(16)}, x0 = ${x0Num.toString(16)}, x1 = ${x1Num.toString(16)}`);
+        
+        let instructionResponse = send_command(`m${pcNum.toString(16)},4`);
+        log(`instruction at pc: ${instructionResponse}`);
+        let instrU32 = littleEndianHexToU32(instructionResponse);
+        let brkImmediate = extractBrkImmediate(instrU32);
+        log(`BRK immediate: 0x${brkImmediate.toString(16)} (${brkImmediate})`);
+        
+        if (brkImmediate !== 0x69) {
+            log(`Skipping breakpoint: brk immediate was not 0x69 (was 0x${brkImmediate.toString(16)})`);
+            continue;
+        }
+        
+        log(`BRK immediate matches expected value 0x69 - processing valid breakpoint ${validBreakpoints + 1}/${breakpointcount}`);
+        
+        log(`Allocated JIT page at address: 0x${x0Num.toString(16)}`);
+        
+        let prepareJITPageResponse = prepare_memory_region(x0Num, x1Num);
+        log(`prepareJITPageResponse = ${prepareJITPageResponse}`);
+        
+        let pcPlus4 = numberToLittleEndianHexString(pcNum + 4n);
+        let pcPlus4Response = send_command(`P20=${pcPlus4};thread:${tid};`);
+        log(`pcPlus4Response = ${pcPlus4Response}`);
+        
+        validBreakpoints++;
+        log(`Completed valid breakpoint ${validBreakpoints}/${breakpointcount}`);
+    }
+    
+    let detachResponse = send_command(`D`);
+    log(`detachResponse = ${detachResponse}`);
+}
+
+attach(1);

Sources/BundledScript.swift

@@ -2,9 +2,9 @@ import Foundation
 
 enum BundledScript {
 
-    static func universalJS() throws -> String {
+    static func source(for script: StikJIT.Script) throws -> String {
         let bundle = Bundle(for: BundleToken.self)
-        guard let url = bundle.url(forResource: "universal", withExtension: "js"),
+        guard let url = bundle.url(forResource: script.resourceName, withExtension: "js"),
               let source = try? String(contentsOf: url, encoding: .utf8),
               !source.isEmpty else {
             throw StikJITError.scriptUnavailable

Sources/JITSession.swift

@@ -29,7 +29,7 @@ final class JITSession {
         self.configuration = configuration
     }
 
-    func enableJIT(targetPID: Int32, progress: @escaping (String) -> Void) throws {
+    func enableJIT(targetPID: Int32, script: StikJIT.Script, progress: @escaping (String) -> Void) throws {
         let tunnel = try makeTunnel()
         defer { tunnel.free() }
 
@@ -43,7 +43,7 @@ final class JITSession {
         debug_proxy_set_ack_mode(debugProxy, 0)
 
         if ProcessInfo.processInfo.hasTXM {
-            try ScriptRunner(targetPID: targetPID, debugProxy: debugProxy, progress: progress).run()
+            try ScriptRunner(targetPID: targetPID, debugProxy: debugProxy, script: script, progress: progress).run()
         } else {
             try attachWithoutScript(targetPID: targetPID, debugProxy: debugProxy, progress: progress)
         }

Sources/ScriptRunner.swift

@@ -8,17 +8,19 @@ final class ScriptRunner {
 
     private let targetPID: Int32
     private let debugProxy: OpaquePointer
+    private let script: StikJIT.Script
     private let progress: (String) -> Void
     private var context: JSContext?
 
-    init(targetPID: Int32, debugProxy: OpaquePointer, progress: @escaping (String) -> Void) {
+    init(targetPID: Int32, debugProxy: OpaquePointer, script: StikJIT.Script, progress: @escaping (String) -> Void) {
         self.targetPID = targetPID
         self.debugProxy = debugProxy
+        self.script = script
         self.progress = progress
     }
 
     func run() throws {
-        let source = try BundledScript.universalJS()
+        let source = try BundledScript.source(for: script)
 
         guard let context = JSContext() else { throw StikJITError.scriptUnavailable }
         self.context = context
@@ -45,7 +47,7 @@ final class ScriptRunner {
         context.setObject(prepare, forKeyedSubscript: "prepare_memory_region" as NSString)
         context.setObject(log,     forKeyedSubscript: "log" as NSString)
 
-        progress("Running universal.js against pid \(targetPID)…")
+        progress("Running \(script.resourceName).js against pid \(targetPID)…")
         context.evaluateScript(source)
         progress("JIT script finished (region blessed, detached).")
     }

Sources/StikJIT.swift

@@ -2,6 +2,20 @@ import Foundation
 
 public enum StikJIT {
 
+    public enum Script: Sendable {
+
+        case universal
+
+        case legacy
+
+        var resourceName: String {
+            switch self {
+            case .universal: return "universal"
+            case .legacy: return "legacy"
+            }
+        }
+    }
+
     public struct Configuration: Sendable {
 
         public var deviceAddress: String
@@ -19,8 +33,9 @@ public enum StikJIT {
     public static func enableJIT(targetPID: Int32,
                                  pairingFile: URL,
                                  configuration: Configuration = .default,
+                                 script: Script = .universal,
                                  progress: @escaping (String) -> Void = { _ in }) throws {
         let session = JITSession(pairingFilePath: pairingFile.path, configuration: configuration)
-        try session.enableJIT(targetPID: targetPID, progress: progress)
+        try session.enableJIT(targetPID: targetPID, script: script, progress: progress)
     }
 }

Sources/StikJITError.swift

@@ -15,7 +15,7 @@ public enum StikJITError: Error, LocalizedError {
         case .pairingFile(let detail):
             return "Pairing file error: \(detail)."
         case .scriptUnavailable:
-            return "The bundled universal.js could not be loaded from the StikJIT framework."
+            return "The bundled JIT script could not be loaded from the StikJIT framework."
         case .debugProxyUnavailable:
             return "Failed to establish a debugserver connection to the target process."
         case .device(let code, let subCode, let message):