On Sat, 9 Aug 2025 19:50:14 GMT, Philippe Marschall <d...@openjdk.org> wrote:
> Reduce the usage of JNI in the Linux attach provider by making more use of > the `Path` API. > > - use the `Path` API to read file permissions > - use the `Path` API to write to and read from Unix domain sockets > - use JDK internal APIs to access the euid and eguid > > After this the sole usage of JNI in the Linux attach provider will be to send > a signal using `kill`. > > I ran the tier1 and serviceability test suites and they both pass. I verified > I can attach to and attach using a locally built JDK. I didn't do any Docker > related tests. > > I split the changes into two commits: > > - The first commit ports the permission check code more or less directly from > C to Java using integer based checks. > - The second commit changes the permission check code to use higher level > Java abstractions (`UserPrincipal`, `Set`, ...) > > I hope this makes it easier to review and verify the changes preserve the > semantics. > > To the best of my knowledge `uid_t` is an unsigned 32 bit integer. > `VM#geteuid()` returns it as `long`, unsigned. However > `UnixUserPrincipals#fromUid` expects an `int`, I believe casting is the > correct way to convert in this case. > > I tried to keep unrelated changes to `VirtualMachineImpl` to a minimum. I did > however replace all usages of `java.io.File` with `java.nio.file.Path` and > made two methods `static`. We could get rid of the `socket_path` instance > variable if we instead use `socket_address` to flag a disconnect. > > Ultimately the same changes can be applied to the macOS an AIX > implementations. Thanks for the work so far, nice to get rid of JNI. :slightly_smiling_face: There is a [problemlisted test](https://github.com/openjdk/jdk/pull/21417) related to this that could make sense to run manually (https://bugs.openjdk.org/browse/JDK-8341518, it's failing in Oracle's CI but I have not been able to reproduce the failure myself, discussed a bit in https://github.com/openjdk/jdk/pull/21331 too). I'll see if I can find time to check out this change locally and run some tests, otherwise, feel free to run it yourself. ------------- PR Comment: https://git.openjdk.org/jdk/pull/26712#issuecomment-3173574572
