[AltServer] Adds ALTDebugConnection to “debug” sideloaded apps

Allows AltServer to programmatically enable JIT execution in sideloaded apps.

AltServer/Connections/ALTDebugConnection+Private.h

@@ -0,0 +1,28 @@
+//
+//  ALTDebugConnection+Private.h
+//  AltServer
+//
+//  Created by Riley Testut on 2/19/21.
+//  Copyright © 2021 Riley Testut. All rights reserved.
+//
+
+#import "ALTDebugConnection.h"
+
+#include <libimobiledevice/libimobiledevice.h>
+#include <libimobiledevice/debugserver.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface ALTDebugConnection ()
+
+@property (nonatomic, readonly) dispatch_queue_t connectionQueue;
+
+@property (nonatomic, nullable) debugserver_client_t client;
+
+- (instancetype)initWithDevice:(ALTDevice *)device;
+
+- (void)connectWithCompletionHandler:(void (^)(BOOL success, NSError *_Nullable error))completionHandler;
+
+@end
+
+NS_ASSUME_NONNULL_END

AltServer/Connections/ALTDebugConnection.h

@@ -0,0 +1,24 @@
+//
+//  ALTDebugConnection.h
+//  AltServer
+//
+//  Created by Riley Testut on 2/19/21.
+//  Copyright © 2021 Riley Testut. All rights reserved.
+//
+
+#import "AltSign.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+NS_SWIFT_NAME(DebugConnection)
+@interface ALTDebugConnection : NSObject
+
+@property (nonatomic, copy, readonly) ALTDevice *device;
+
+- (void)enableUnsignedCodeExecutionForProcessWithName:(NSString *)processName completionHandler:(void (^)(BOOL success, NSError *_Nullable error))completionHandler;
+
+- (void)disconnect;
+
+@end
+
+NS_ASSUME_NONNULL_END

AltServer/Connections/ALTDebugConnection.mm

@@ -0,0 +1,249 @@
+//
+//  ALTDebugConnection.m
+//  AltServer
+//
+//  Created by Riley Testut on 2/19/21.
+//  Copyright © 2021 Riley Testut. All rights reserved.
+//
+
+#import "ALTDebugConnection+Private.h"
+
+#import "NSError+ALTServerError.h"
+#import "NSError+libimobiledevice.h"
+
+char *bin2hex(const unsigned char *bin, size_t length)
+{
+    if (bin == NULL || length == 0)
+    {
+        return NULL;
+    }
+
+    char *hex = (char *)malloc(length * 2 + 1);
+    for (size_t i = 0; i < length; i++)
+    {
+        hex[i * 2] = "0123456789ABCDEF"[bin[i] >> 4];
+        hex[i * 2 + 1] = "0123456789ABCDEF"[bin[i] & 0x0F];
+    }
+    hex[length * 2] = '\0';
+
+    return hex;
+}
+
+@implementation ALTDebugConnection
+
+- (instancetype)initWithDevice:(ALTDevice *)device
+{
+    self = [super init];
+    if (self)
+    {
+        _device = device;
+        _connectionQueue = dispatch_queue_create_with_target("io.altstore.AltServer.DebugConnection",
+                                                             DISPATCH_QUEUE_SERIAL_WITH_AUTORELEASE_POOL,
+                                                             dispatch_get_global_queue(QOS_CLASS_DEFAULT, 0));
+    }
+    
+    return self;
+}
+
+- (void)dealloc
+{
+    [self disconnect];
+}
+
+- (void)disconnect
+{
+    if (_client == nil)
+    {
+        return;
+    }
+    
+    debugserver_client_free(_client);
+    _client = nil;
+}
+
+- (void)connectWithCompletionHandler:(void (^)(BOOL success, NSError *_Nullable error))completionHandler
+{
+    __block idevice_t device = NULL;
+    
+    void (^finish)(BOOL, NSError *) = ^(BOOL success, NSError *error) {
+        if (device)
+        {
+            idevice_free(device);
+        }
+        
+        completionHandler(success, error);
+    };
+    
+    dispatch_async(self.connectionQueue, ^{
+        /* Find Device */
+        if (idevice_new_with_options(&device, self.device.identifier.UTF8String, (enum idevice_options)((int)IDEVICE_LOOKUP_NETWORK | (int)IDEVICE_LOOKUP_USBMUX)) != IDEVICE_E_SUCCESS)
+        {
+            return finish(NO, [NSError errorWithDomain:AltServerErrorDomain code:ALTServerErrorDeviceNotFound userInfo:nil]);
+        }
+                
+        /* Connect to debugserver */
+        debugserver_client_t client = NULL;
+        debugserver_error_t error = debugserver_client_start_service(device, &client, "AltServer");
+        if (error != DEBUGSERVER_E_SUCCESS)
+        {
+            return finish(NO, [NSError errorWithDebugServerError:error device:self.device]);
+        }
+        
+        self.client = client;
+        
+        finish(YES, nil);
+    });
+}
+
+- (void)enableUnsignedCodeExecutionForProcessWithName:(NSString *)processName completionHandler:(void (^)(BOOL success, NSError *_Nullable error))completionHandler
+{
+    dispatch_async(self.connectionQueue, ^{
+        NSString *localizedFailure = [NSString stringWithFormat:NSLocalizedString(@"JIT could not be enabled for %@.", comment: @""), processName];
+        
+        NSString *encodedName = @(bin2hex((const unsigned char *)processName.UTF8String, (size_t)strlen(processName.UTF8String)));
+        NSString *attachCommand = [NSString stringWithFormat:@"vAttachName;%@", encodedName];
+        
+        NSError *error = nil;
+        if (![self sendCommand:attachCommand arguments:nil error:&error])
+        {
+            NSMutableDictionary *userInfo = [error.userInfo mutableCopy];
+            userInfo[ALTAppNameErrorKey] = processName;
+            userInfo[ALTDeviceNameErrorKey] = self.device.name;
+            userInfo[NSLocalizedFailureErrorKey] = localizedFailure;
+            
+            NSError *returnError = [NSError errorWithDomain:error.domain code:error.code userInfo:userInfo];
+            return completionHandler(NO, returnError);
+        }
+        
+        NSString *detachCommand = @"D";
+        if (![self sendCommand:detachCommand arguments:nil error:&error])
+        {
+            NSMutableDictionary *userInfo = [error.userInfo mutableCopy];
+            userInfo[ALTAppNameErrorKey] = processName;
+            userInfo[ALTDeviceNameErrorKey] = self.device.name;
+            userInfo[NSLocalizedFailureErrorKey] = localizedFailure;
+            
+            NSError *returnError = [NSError errorWithDomain:error.domain code:error.code userInfo:userInfo];
+            return completionHandler(NO, returnError);
+        }
+        
+        completionHandler(YES, nil);
+    });
+}
+
+#pragma mark - Private -
+
+- (BOOL)sendCommand:(NSString *)command arguments:(nullable NSArray<NSString *> *)arguments error:(NSError **)error
+{
+    int argc = (int)arguments.count;
+    char **argv = new char*[argc + 1];
+    
+    for (int i = 0; i < argc; i++)
+    {
+        NSString *argument = arguments[i];
+        argv[i] = (char *)argument.UTF8String;
+    }
+    
+    argv[argc] = NULL;
+    
+    debugserver_command_t debugCommand = NULL;
+    debugserver_command_new(command.UTF8String, argc, argv, &debugCommand);
+    
+    delete[] argv;
+    
+    char *response = NULL;
+    size_t responseSize = 0;
+    debugserver_error_t debugServerError = debugserver_client_send_command(self.client, debugCommand, &response, &responseSize);
+    debugserver_command_free(debugCommand);
+    
+    if (debugServerError != DEBUGSERVER_E_SUCCESS)
+    {
+        if (error)
+        {
+            *error = [NSError errorWithDebugServerError:debugServerError device:self.device];
+        }
+        
+        return NO;
+    }
+        
+    if (![self processResponse:@(response) error:error])
+    {
+        return NO;
+    }
+    
+    return YES;
+}
+
+- (BOOL)processResponse:(NSString *)rawResponse error:(NSError **)error
+{
+    if (rawResponse.length == 0 || [rawResponse isEqualToString:@"OK"])
+    {
+        return YES;
+    }
+    
+    char type = [rawResponse characterAtIndex:0];
+    NSString *response = [rawResponse substringFromIndex:1];
+    
+    switch (type)
+    {
+        case 'O':
+        {
+            // stdout/stderr
+            
+            char *decodedResponse = NULL;
+            debugserver_decode_string(response.UTF8String, response.length, &decodedResponse);
+            
+            NSLog(@"Response: %@", @(decodedResponse));
+            
+            if (decodedResponse)
+            {
+                free(decodedResponse);
+            }
+            
+            return YES;
+        }
+            
+        case 'T':
+        {
+            // Thread Information
+            
+            NSLog(@"Thread stopped. Details:\n%s", response.UTF8String + 1);
+            return YES;
+        }
+            
+        case 'E':
+        {
+            // Error
+            
+            if (error)
+            {
+                NSInteger errorCode = [[[response componentsSeparatedByString:@";"] firstObject] integerValue];
+                
+                switch (errorCode)
+                {
+                    case 96:
+                        *error = [NSError errorWithDomain:AltServerErrorDomain code:ALTServerErrorRequestedAppNotRunning userInfo:nil];
+                        break;
+                        
+                    default:
+                        *error = [NSError errorWithDomain:AltServerConnectionErrorDomain code:ALTServerConnectionErrorUnknown userInfo:@{NSLocalizedFailureReasonErrorKey: response}];
+                        break;
+                }
+            }
+            
+            return NO;
+        }
+            
+        case 'W':
+        {
+            // Warning
+            
+            NSLog(@"WARNING: %@", response);
+            return YES;
+        }
+    }
+    
+    return YES;
+}
+
+@end

AltServer/Devices/ALTDeviceManager.h

@@ -11,6 +11,7 @@
 
 @class ALTWiredConnection;
 @class ALTNotificationConnection;
+@class ALTDebugConnection;
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -43,6 +44,7 @@ extern NSNotificationName const ALTDeviceManagerDeviceDidDisconnectNotification
 /* Connections */
 - (void)startWiredConnectionToDevice:(ALTDevice *)device completionHandler:(void (^)(ALTWiredConnection *_Nullable connection, NSError *_Nullable error))completionHandler;
 - (void)startNotificationConnectionToDevice:(ALTDevice *)device completionHandler:(void (^)(ALTNotificationConnection *_Nullable connection, NSError *_Nullable error))completionHandler;
+- (void)startDebugConnectionToDevice:(ALTDevice *)device completionHandler:(void (^)(ALTDebugConnection *_Nullable connection, NSError * _Nullable error))completionHandler;
 
 @end
 

AltServer/Devices/ALTDeviceManager.mm

@@ -10,6 +10,7 @@
 
 #import "ALTWiredConnection+Private.h"
 #import "ALTNotificationConnection+Private.h"
+#import "ALTDebugConnection+Private.h"
 
 #import "ALTConstants.h"
 #import "NSError+ALTServerError.h"
@@ -1277,6 +1278,20 @@ NSNotificationName const ALTDeviceManagerDeviceDidDisconnectNotification = @"ALT
     completionHandler(notificationConnection, nil);
 }
 
+- (void)startDebugConnectionToDevice:(ALTDevice *)device completionHandler:(void (^)(ALTDebugConnection * _Nullable, NSError * _Nullable))completionHandler
+{
+    ALTDebugConnection *connection = [[ALTDebugConnection alloc] initWithDevice:device];
+    [connection connectWithCompletionHandler:^(BOOL success, NSError * _Nullable error) {
+        if (success)
+        {
+            completionHandler(connection, nil);
+        }
+        else
+        {
+            completionHandler(nil, error);
+        }
+    }];
+}
 #pragma mark - Getters -
 
 - (NSArray<ALTDevice *> *)connectedDevices

AltStore.xcodeproj/project.pbxproj

@@ -212,6 +212,7 @@
 		BF9ABA4D22DD16DE008935CF /* PillButton.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF9ABA4C22DD16DE008935CF /* PillButton.swift */; };
 		BFA8172923C56042001B5953 /* ServerConnection.swift in Sources */ = {isa = PBXBuildFile; fileRef = BFA8172823C56042001B5953 /* ServerConnection.swift */; };
 		BFA8172B23C5633D001B5953 /* FetchAnisetteDataOperation.swift in Sources */ = {isa = PBXBuildFile; fileRef = BFA8172A23C5633D001B5953 /* FetchAnisetteDataOperation.swift */; };
+		BFAD678E25E0649500D4C4D1 /* ALTDebugConnection.mm in Sources */ = {isa = PBXBuildFile; fileRef = BFAD678D25E0649500D4C4D1 /* ALTDebugConnection.mm */; };
 		BFAD67A325E0854500D4C4D1 /* DeveloperDiskManager.swift in Sources */ = {isa = PBXBuildFile; fileRef = BFAD67A225E0854500D4C4D1 /* DeveloperDiskManager.swift */; };
 		BFAECC522501B0A400528F27 /* CodableServerError.swift in Sources */ = {isa = PBXBuildFile; fileRef = BFD44605241188C300EAB90A /* CodableServerError.swift */; };
 		BFAECC532501B0A400528F27 /* ServerProtocol.swift in Sources */ = {isa = PBXBuildFile; fileRef = BF1E3128229F474900370A3C /* ServerProtocol.swift */; };
@@ -679,6 +680,9 @@
 		BF9ABA4C22DD16DE008935CF /* PillButton.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PillButton.swift; sourceTree = "<group>"; };
 		BFA8172823C56042001B5953 /* ServerConnection.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ServerConnection.swift; sourceTree = "<group>"; };
 		BFA8172A23C5633D001B5953 /* FetchAnisetteDataOperation.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FetchAnisetteDataOperation.swift; sourceTree = "<group>"; };
+		BFAD678C25E0649500D4C4D1 /* ALTDebugConnection.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = ALTDebugConnection.h; sourceTree = "<group>"; };
+		BFAD678D25E0649500D4C4D1 /* ALTDebugConnection.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = ALTDebugConnection.mm; sourceTree = "<group>"; };
+		BFAD679525E064D400D4C4D1 /* ALTDebugConnection+Private.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "ALTDebugConnection+Private.h"; sourceTree = "<group>"; };
 		BFAD67A225E0854500D4C4D1 /* DeveloperDiskManager.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DeveloperDiskManager.swift; sourceTree = "<group>"; };
 		BFB1169C22932DB100BB457C /* apps.json */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.json; path = apps.json; sourceTree = "<group>"; };
 		BFB364592325985F00CD0EB1 /* FindServerOperation.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FindServerOperation.swift; sourceTree = "<group>"; };
@@ -1566,6 +1570,9 @@
 				BF718BD323C928A300A89F2D /* ALTNotificationConnection.h */,
 				BF718BD623C92B3700A89F2D /* ALTNotificationConnection+Private.h */,
 				BF718BD423C928A300A89F2D /* ALTNotificationConnection.mm */,
+				BFAD678C25E0649500D4C4D1 /* ALTDebugConnection.h */,
+				BFAD679525E064D400D4C4D1 /* ALTDebugConnection+Private.h */,
+				BFAD678D25E0649500D4C4D1 /* ALTDebugConnection.mm */,
 			);
 			path = Connections;
 			sourceTree = "<group>";
@@ -2288,6 +2295,7 @@
 				BF718BD523C928A300A89F2D /* ALTNotificationConnection.mm in Sources */,
 				BF1E312B229F474900370A3C /* RequestHandler.swift in Sources */,
 				BF718BD123C91BD300A89F2D /* ALTWiredConnection.mm in Sources */,
+				BFAD678E25E0649500D4C4D1 /* ALTDebugConnection.mm in Sources */,
 				BFECAC8524FD950B0077C41F /* Connection.swift in Sources */,
 				BF458690229872EA00BD7491 /* AppDelegate.swift in Sources */,
 				BFECAC8424FD950B0077C41F /* ALTConstants.m in Sources */,

Shared/Categories/NSError+ALTServerError.h

@@ -46,6 +46,8 @@ typedef NS_ERROR_ENUM(AltServerErrorDomain, ALTServerError)
     ALTServerErrorProfileNotFound = 15,
     
     ALTServerErrorAppDeletionFailed = 16,
+    
+    ALTServerErrorRequestedAppNotRunning = 100,
 };
 
 typedef NS_ERROR_ENUM(AltServerConnectionErrorDomain, ALTServerConnectionError)

Shared/Categories/NSError+ALTServerError.m

@@ -124,6 +124,13 @@ NSErrorUserInfoKey const ALTDeviceNameErrorKey = @"deviceName";
             
         case ALTServerErrorAppDeletionFailed:
             return NSLocalizedString(@"An error occured while removing the app.", @"");
+            
+        case ALTServerErrorRequestedAppNotRunning:
+        {
+            NSString *appName = self.userInfo[ALTAppNameErrorKey] ?: NSLocalizedString(@"The requested app", @"");
+            NSString *deviceName = self.userInfo[ALTDeviceNameErrorKey] ?: NSLocalizedString(@"the device", @"");
+            return [NSString stringWithFormat:NSLocalizedString(@"%@ is not currently running on %@.", ""), appName, deviceName];
+        }
     }
 }
 
@@ -141,6 +148,12 @@ NSErrorUserInfoKey const ALTDeviceNameErrorKey = @"deviceName";
         case ALTServerErrorMaximumFreeAppLimitReached:
             return NSLocalizedString(@"Make sure “Offload Unused Apps” is disabled in Settings > iTunes & App Stores, then install or delete all offloaded apps.", @"");
             
+        case ALTServerErrorRequestedAppNotRunning:
+        {
+            NSString *deviceName = self.userInfo[ALTDeviceNameErrorKey] ?: NSLocalizedString(@"your device", @"");
+            return [NSString stringWithFormat:NSLocalizedString(@"Make sure the app is running in the foreground on %@ then try again.", @""), deviceName];
+        }
+            
         default:
             return nil;
     }