4 ms·

For most of Wine's life it was sufficient to implement the system library ABI, but recent developments mean they also have to trap the (unstable) syscall ABI wi

by mappu 2y ago

For most of Wine's life it was sufficient to implement the system library ABI, but recent developments mean they also have to trap the (unstable) syscall ABI with ptrace. You could mimic Binder in userspace the same way, without the kernel module. But even that's not a problem since Binder is upstream and enabled by default in many distro kernels now.

ronsor 2y ago
When did WINE start doing this? I always love a good read on ptrace hacks.
- lights0123 2y ago
  https://github.com/wine-staging/wine-staging/commit/595f2f9860adafed612737529745ad24c50acdb9 https://github.com/wine-staging/wine-staging/commit/595f2f98... A new strategy is used that is much faster: https://www.phoronix.com/news/Syscall-User-Dispatch-Queued https://www.phoronix.com/news/Syscall-User-Dispatch-Queued
  - quotemstr 2y ago
    > Games avoiding the Windows API and performing system calls directly is an increasingly common occurrence by modern Windows games, seemingly in the name of Digital Rights Management schemes and similar protected modes. Yuck. Windows system call numbers are not contractual. At all. Microsoft should try harder to kill any code outside ntdll.dll that makes a system call. It's obnoxious for a developer to deliberately use unstable interfaces and then demand indefinite compatibility.
    - lxgr 2y ago
      > demand indefinite compatibility. Not infinite – long enough for the game to bring in most revenue is enough. Who cares that it stops running one or two Windows updates later for totally avoidable reasons? Definitely not the publisher. (In fact, isn't it about time for an HD remaster again?)
      - quotemstr 2y ago
        Microsoft cares, though, because if a game stops working when you upgrade Windows, you blame the Windows upgrade, not Microsoft. So now Microsoft has to maintain these legacy system calls even though they never signed up to do that.
        ronsor 2y ago
        Microsoft does not. This is the one area where they don't compromise: system call numbers regularly change between Windows builds.
    - int0x29 2y ago
      There is now at least one public windows kernel call listed on MSDN: __fastfail https://learn.microsoft.com/en-us/cpp/intrinsics/fastfail?view=msvc-170 https://learn.microsoft.com/en-us/cpp/intrinsics/fastfail?vi...
      - quotemstr 2y ago
        I'd call that a special ABI feature, not a stable system call. Note that it's a software interrupt, not a regular SYSENTER. But sure. Maybe I'm splitting hairs.
augusto-moura 2y ago
I don't think binder is upstream, nor is the default in many distros. AFAIK support is very limited as not a lot of people use it. In arch it is provided only as a community package (AUR) [1]. This was a major blocker for me when trying to install anbox or waydroid, custom compiled kernel modules is a no-no for me, not because of security issues (which could exist), but because they can break a lot of stuff and fixing kernel modules is not a stroll in the park. [1]: https://aur.archlinux.org/packages/binder_linux-dkms https://aur.archlinux.org/packages/binder_linux-dkms
- yjftsjthsd-h 2y ago
  I'm reasonably confident that it is upstream: https://github.com/torvalds/linux/blob/master/drivers/android/binder.c https://github.com/torvalds/linux/blob/master/drivers/androi... looks like the most obvious bit, though there are other pieces. (And now I'm curious why waydroid is maintaining their own dkms code separate from that; perhaps it's to better target a range of kernel versions?) I will agree that it's not generally actually built/used by distros.
- ac29 2y ago
  It is upstream and Arch gives directions for enabling it in the standard kernel: https://wiki.archlinux.org/title/Waydroid#Building_a_kernel https://wiki.archlinux.org/title/Waydroid#Building_a_kernel
- mappu 2y ago
  It was moved from linux-staging to proper Linux in 2014 [1], and it's included with Debian oldoldstable, oldstable, and stable as well as Ubuntu linux-image packages, as a module binder_linux.ko; just need to modprobe binder. 1. https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/drivers/android/binder.c?ofs=200 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/lin... 2. https://packages.debian.org/search?suite=buster&arch=any&mode=filename&searchon=contents&keywords=binder_linux.ko https://packages.debian.org/search?suite=buster&arch=any&mod...

by mappu 2y ago

ronsor 2y ago

When did WINE start doing this? I always love a good read on ptrace hacks.

lights0123 2y ago
https://github.com/wine-staging/wine-staging/commit/595f2f9860adafed612737529745ad24c50acdb9 https://github.com/wine-staging/wine-staging/commit/595f2f98... A new strategy is used that is much faster: https://www.phoronix.com/news/Syscall-User-Dispatch-Queued https://www.phoronix.com/news/Syscall-User-Dispatch-Queued
- quotemstr 2y ago
  > Games avoiding the Windows API and performing system calls directly is an increasingly common occurrence by modern Windows games, seemingly in the name of Digital Rights Management schemes and similar protected modes. Yuck. Windows system call numbers are not contractual. At all. Microsoft should try harder to kill any code outside ntdll.dll that makes a system call. It's obnoxious for a developer to deliberately use unstable interfaces and then demand indefinite compatibility.
  - lxgr 2y ago
    > demand indefinite compatibility. Not infinite – long enough for the game to bring in most revenue is enough. Who cares that it stops running one or two Windows updates later for totally avoidable reasons? Definitely not the publisher. (In fact, isn't it about time for an HD remaster again?)
    - quotemstr 2y ago
      Microsoft cares, though, because if a game stops working when you upgrade Windows, you blame the Windows upgrade, not Microsoft. So now Microsoft has to maintain these legacy system calls even though they never signed up to do that.
      - ronsor 2y ago
        Microsoft does not. This is the one area where they don't compromise: system call numbers regularly change between Windows builds.
  - int0x29 2y ago
    There is now at least one public windows kernel call listed on MSDN: __fastfail https://learn.microsoft.com/en-us/cpp/intrinsics/fastfail?view=msvc-170 https://learn.microsoft.com/en-us/cpp/intrinsics/fastfail?vi...
    - quotemstr 2y ago
      I'd call that a special ABI feature, not a stable system call. Note that it's a software interrupt, not a regular SYSENTER. But sure. Maybe I'm splitting hairs.

augusto-moura 2y ago

I don't think binder is upstream, nor is the default in many distros. AFAIK support is very limited as not a lot of people use it. In arch it is provided only as a community package (AUR) [1]. This was a major blocker for me when trying to install anbox or waydroid, custom compiled kernel modules is a no-no for me, not because of security issues (which could exist), but because they can break a lot of stuff and fixing kernel modules is not a stroll in the park. [1]: https://aur.archlinux.org/packages/binder_linux-dkms https://aur.archlinux.org/packages/binder_linux-dkms

yjftsjthsd-h 2y ago
I'm reasonably confident that it is upstream: https://github.com/torvalds/linux/blob/master/drivers/android/binder.c https://github.com/torvalds/linux/blob/master/drivers/androi... looks like the most obvious bit, though there are other pieces. (And now I'm curious why waydroid is maintaining their own dkms code separate from that; perhaps it's to better target a range of kernel versions?) I will agree that it's not generally actually built/used by distros.
ac29 2y ago
It is upstream and Arch gives directions for enabling it in the standard kernel: https://wiki.archlinux.org/title/Waydroid#Building_a_kernel https://wiki.archlinux.org/title/Waydroid#Building_a_kernel
mappu 2y ago
It was moved from linux-staging to proper Linux in 2014 [1], and it's included with Debian oldoldstable, oldstable, and stable as well as Ubuntu linux-image packages, as a module binder_linux.ko; just need to modprobe binder. 1. https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/drivers/android/binder.c?ofs=200 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/lin... 2. https://packages.debian.org/search?suite=buster&arch=any&mode=filename&searchon=contents&keywords=binder_linux.ko https://packages.debian.org/search?suite=buster&arch=any&mod...