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0 pointspjmlp2d ago0 comments

No you cannot, the NDK has a specific set of oficial APIS, and the Android team feels in the right to kill any application that doesn't follow the law of Android land.

Some folks like the termux rebels, occasionally find out there is a sherif in town.

> As documented in the Android N behavioral changes, to protect Android users and apps from unforeseen crashes, Android N will restrict which libraries your C/C++ code can link against at runtime. As a result, if your app uses any private symbols from platform libraries, you will need to update it to either use the public NDK APIs or to include its own copy of those libraries. Some libraries are public: the NDK exposes libandroid, libc, libcamera2ndk, libdl, libGLES, libjnigraphics, liblog, libm, libmediandk, libOpenMAXAL, libOpenSLES, libstdc++, libvulkan, and libz as part of the NDK API. Other libraries are private, and Android N only allows access to them for platform HALs, system daemons, and the like. If you aren’t sure whether your app uses private libraries, you can immediately check it for warnings on the N Developer Preview.

https://android-developers.googleblog.com/2016/06/improving-...

These stable APIs,

https://developer.android.com/ndk/guides/stable_apis

0 comments

tadfisher2d ago

What's amazing about Linux is that you don't have to use the system's libc, and you don't have to use dynamic linking.

That said, newer Androids use seccomp to restrict which syscalls you can use, basically to what bionic exposes anyway. This doesn't seem to affect Termux and friends, which can apparently run full X11 applications without root.

(edit) Notably, splice() is still callable, so maybe the POC needs to be tweaked...

stevenhuang2d ago

That's all user space platform specifics, it has no relation to your previous statement where you said 'android is not linux'.

Someone can statically build a freestanding executable/so targetting arm64 linux (specifically the right android linux kernel version) and it will run fine on Android. The syscall interface, process model, file descriptors, signals, memory mapping, all of this is Linux, this is what people mean when they say Android is just Linux.

dzaima2d ago

That's specific libraries, when using the default linker. You could construct that same behavior on desktop linux too. And you can avoid it equally well on Android - you can statically-link things just fine, you can use libraries you actually control, and presumably use a custom linker if desired. It's utterly non-surprising that "you run code you don't control" results in "said code...can do arbitrary things for unsupported use". (Never mind that, instead of a "sherif", they could've just renamed all private symbols, or just naturally replaced them over time, breaking your code all the same, just in a more confusing way)

Also some obligatory Linux vs GNU/Linux comment. (and it's not like GNU/Linux doesn't ever change under your feet - see the glibc DT_HASH debacle)

esseph2d ago

https://www.androidpolice.com/google-support-linux-kernels-a...

Google relies on Linux LTS kernels. When the Linux LTS team dropped support from 6 years down to 2 years, Google stepped in to cover the 4-year gap.

It is Linux. It's basically a distro.

anthk2d ago

- Waydroid

- Is totally Linux

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