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lldb support?

append delete Graeme Love

I noticed that there are LLDB executables in the toolchain. Is it supported?

I've written a python script to install & run applications on the iOS device (not jailbroken). This script has to launch the debug server on the device and speaks enough of the GDB protocol to launch my application.

In theory, this script could function as a debug proxy server between LLDB and the device by just relaying traffic between the iOS debugserver and LLDB.

It would be really cool to have debugging on the device from Win64.

Cheers,

Graeme

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append delete #1. Pierre-Marie Baty

Hello Graeme,

Congratulations for being a power user. It’s a pleasure to read stories like that.

I guess your script uses libimobiledevice, doesn’t it ?

To my knowledge the debug server on iOS may only be started over a USB cable through that protocol. Is it what you’re referring to ?

append delete #2. Graeme Love

Hi,

No it doesn't actually use libimobiledevice, although I did read a lot of their code to help decipher some things that were going on. It makes use of CoreFramework.dll and MobileDevice.dll which are installed by AppleMobileDeviceSupport64.msi. I've used ctypes to wrap a bunch of functions provided by these dlls to interact with the iOS device.

I also took a lot of inspiration from https://github.com/ios-control/ios-deploy and how they interact with the debug server on iOS.

Current I am connecting my iOS device with a USB cable and starting up the iOS debug server and telling it to run my application (similar to what the utility https://github.com/ghughes/fruitstrap used to do).

ios-deploy takes that a bit further and uses LLDB on the Mac to talk to the device using debugger scripts. It would be good to have a version of LLDB that was runnable from Win64.

libimobiledevice does have a debug server proxy utility which is what I was experimenting with al0ng with the version of LLDB in the toolchain. I tried running the command "platform select remote-ios" in LLDB but it complained about the SDK not being present. Did you make any changes to LLDB when you built it, or is it pretty vanilla? I'm wondering if I can pull the files necessary to run LLDB from my Mac.

Thanks,

Graeme

append delete #3. Pierre-Marie Baty

It’s quasi-vanilla (the only real change is the "symlink" support in all pathnames - all one-liner files whose content can be resolved as an existing path are considered symbolic links and automatically dereferenced) and indeed a few changes would be necessary to make it locate the SDK correctly. I hadn’t investigated there because I never felt a real demand on this topic. But I would gladly work with you to implement that.

append delete #4. Graeme Love

I just checked on my Mac to see if I could find which files it's looking for. Here's the output: 

%
(lldb) platform select remote-ios
  Platform: remote-ios
 Connected: no
  SDK Path: "/Users/glove/Library/Developer/Xcode/iOS DeviceSupport/15.3.1 (19D52)"
 SDK Roots: [ 0] "/Users/glove/Library/Developer/Xcode/iOS DeviceSupport/15.3.1 (19D52)"
 SDK Roots: [ 1] "/Users/glove/Library/Developer/Xcode/iOS DeviceSupport/15.2.1 (19C63)"
%

I'm assuming that these paths aren't currently redirected even if I copied the data from my Mac?

Graeme

append delete #5. Pierre-Marie Baty

Indeed they aren't.

append delete #6. Graeme Love

In case it’s useful, we just released the script back to open source

https://github.com/VelanStudios/fruitstrap

Thanks,

Graeme

append delete #7. Pierre-Marie Baty

Very nice !

There's a lot of bridging code between C library function calls and Python here. I wonder why you chose Python as a language, wouldn't it have been much shorter in C ?

Anyway, thanks a lot. I'm bookmarking this for future reading - hopefully soon.

append delete #8. Graeme Love

One reason is that the same script runs on both MacOS and Windows without needing to compile anything. In my experience, doing anything on MacOS generally involves using a bunch of Apple foundation classes which you can’t compile easily on Windows. Python bridges that gap a bit.

Graeme

append delete #9. Pierre-Marie Baty

Not necessarily. You can perfectly call Objective-C methods in macOS' Foundation libraries directly from C code, although it's neither the usual nor the way of doing things that Apple recommends (and not very documented). But I understand the point.

:: @Pierre-Marie Baty added on 24 Mar ’22 · 15:12

*edit* by the way, all the CoreFoundation APIs are directly callable from plain C. Only the higher level APIs (Foundation and above) are Objective-C, and can be called from C using the ObjC_msgSend() ubiquitous sesame.

:: @Pierre-Marie Baty added on 24 Mar ’22 · 15:20

*2nd edit* Now I can answer more about your idea:

“In theory, this script could function as a debug proxy server between LLDB and the device by just relaying traffic between the iOS debugserver and LLDB.”

Yes, totally. Basically, the goal would be to create a sort of Visual Studio connector. Or, more transparently, expose the remote GDB protocol on a loopback socket that would be directly connectable to by any debugger able to talk the remote GDB/LLDB protocol without needing to worry about the iOS USB SSL handshake, much like a decapsulating TCP proxy.

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