usb library fails on Windows
|Reported by:||basvandijk||Owned by:||simonmar|
|Keywords:||Cc:||Joris Putcuyps <joris.putcuyps@…>, John Obbele <john.obbele@…>, Maurício Antunes <mauricio.antunes@…>|
|Type of failure:||Runtime crash||Test Case:|
|Related Tickets:||Differential Revisions:|
I'm trying to get my Haskell usb library to work on Windows. I currently get a weird error. Please follow the steps below to reproduce the error:
- Download libusb for Windows and extract it somewhere e.g. C:\Program Files\libusb\libusb1.
(Important build-time files: libusb-1.0\include\libusb.h and MinGW32\dll\libusb-1.0.dll.a)
(Important run-time files: MinGW32\dll\libusb-1.0.dll)
- Download, unpack and cabal install the, as of yet unreleased, bindings-DSL-1.0.12 (This version lets you use the right calling convention on Windows (stdcall instead of ccall) by configuring cabal with cc-options: -DBINDINGS_STDCALLCONV)
- Install bindings-libusb:
git clone git://github.com/basvandijk/bindings-libusb.git cd bindings-libusb
Make sure to checkout the windows branch and let cabal know where to find libusb:git checkout windows cabal install --extra-include-dirs="C:\Program Files\libusb\libusb1\include\libusb-1.0" --extra-lib-dirs="C:\Program Files\libusb\libusb1\MinGW32\dll"
- Clone the usb repository:
git clone git://github.com/basvandijk/usb.git cd usbThere's no need to install the library. I included an example program that will demonstrate the error:
cabal configure --flags="example -library" cabal build
The example should read some bytes of an attached USB mouse (change the VID and PID to match your mouse). However it gives two errors:
dist\build\example\example.exe example.exe: NotFoundException Segmentation fault/access violation in generated code
This bug report is about the segmentation fault.
The NotFoundException is thrown by c'libusb_get_config_descriptor which is indirectly called by getDevices. According to the libusb docs this error is thrown when the specified configuration doesn't exists. Since I only call this function on existing configurations this seems like a bug in libusb. I will dive in the libusb source code to see what is going on.
The Segmentation fault/access violation in generated code is caused by the finalizer in newCtx:
newCtx ∷ IO Ctx newCtx = newCtxNoEventManager Ctx libusb_init ∷ IO (Ptr C'libusb_context) libusb_init = alloca $ \ctxPtrPtr → do handleUSBException $ c'libusb_init ctxPtrPtr peek ctxPtrPtr newCtxNoEventManager ∷ (ForeignPtr C'libusb_context → Ctx) → IO Ctx newCtxNoEventManager ctx = mask_ $ do ctxPtr ← libusb_init ctx <$> newForeignPtr p'libusb_exit ctxPtr
When p'libusb_exit is called the segmentation fault occurs.
Note that the error disappears when I change that last line with:
ctx <$> Foreign.Concurrent.newForeignPtr ctxPtr (c'libusb_exit ctxPtr)
I previously got the exact same segmentation fault when calling other bindings-libusb functions. This was caused by using the wrong calling convention on Windows. I used ccall but had to use stdcall. So I assume the current segmentation fault has something to do with the calling convention of FunPtrs.
Any ideas what is causing this? I would really like to solve it. It's the last step before releasing usb-1.0.
Change History (7)
comment:2 Changed 3 years ago by igloo
- Milestone changed from 7.4.1 to 7.6.1
- Priority changed from normal to low
comment:5 Changed 3 years ago by simonmar
- difficulty set to Unknown
- Owner set to simonmar
- Priority changed from low to high