On Sat, 5 Apr 2025 02:36:43 GMT, Francisco Ferrari Bihurriet <fferr...@openjdk.org> wrote:
> Hi, this is a proposal to fix 8352728. > > The main idea is to replace > [`java.nio.file.Path::toRealPath`](https://docs.oracle.com/en/java/javase/24/docs/api/java.base/java/nio/file/Path.html#toRealPath(java.nio.file.LinkOption...)) > by > [`java.io.File::getCanonicalPath`](https://docs.oracle.com/en/java/javase/24/docs/api/java.base/java/io/File.html#getCanonicalPath()) > for path canonicalization purposes. The rationale behind this decision is > the following: > > 1. In _Windows_, `File::getCanonicalPath` handles restricted permissions in > parent directories. Contrarily, `Path::toRealPath` fails with > `AccessDeniedException`. > 2. In _Linux_, `File::getCanonicalPath` handles non-regular files (e.g. > `/dev/stdin`). Contrarily, `Path::toRealPath` fails with > `NoSuchFileException`. > > #### Windows Case > > @martinuy and I tracked down the `File::getCanonicalPath` vs > `Path::toRealPath` behaviour differences in _Windows_. Both methods end up > calling the > [`FindFirstFileW`](https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-findfirstfilew) > API inside a loop for each parent directory in the path, until they include > the leaf: > > * > [`File::getCanonicalPath`](https://github.com/openjdk/jdk/blob/jdk-24-ga/src/java.base/share/classes/java/io/File.java#L618 > "src/java.base/share/classes/java/io/File.java:618") goes through the > following stack into `FindFirstFileW`: > * > [`WinNTFileSystem::canonicalize`](https://github.com/openjdk/jdk/blob/jdk-24-ga/src/java.base/windows/classes/java/io/WinNTFileSystem.java#L473 > "src/java.base/windows/classes/java/io/WinNTFileSystem.java:473") > * > [`WinNTFileSystem::canonicalize0`](https://github.com/openjdk/jdk/blob/jdk-24-ga/src/java.base/windows/native/libjava/WinNTFileSystem_md.c#L288 > "src/java.base/windows/native/libjava/WinNTFileSystem_md.c:288") > * > [`wcanonicalize`](https://github.com/openjdk/jdk/blob/jdk-24-ga/src/java.base/windows/native/libjava/canonicalize_md.c#L233 > "src/java.base/windows/native/libjava/canonicalize_md.c:233") (here is the > loop) > * If `FindFirstFileW` fails with `ERROR_ACCESS_DENIED`, > `lastErrorReportable` is consulted, the error is [considered > non-reportable](https://github.com/openjdk/jdk/blob/jdk-24-ga/src/java.base/windows/native/libjava/canonicalize_md.c#L139 > "src/java.base/windows/native/libjava/canonicalize_md.c:139") and the > iteration is stopped > [here](https://github.com/openjdk/jdk/blob/jdk-24-ga/src/java.base/windows/native/libjava/canonicalize_md.c#L246-L250 > "src/java.base/windows/native/libjava/c... I don't think this change should be integrated. Instead, I think start by finding out why this code is using toRealPath. For the two cases, it looks like toRealPath is correctly failing for the first, but for /dev/stdin then please bring it to nio-dev to discuss how special devices should be handled by that method. ------------- PR Comment: https://git.openjdk.org/jdk/pull/24465#issuecomment-2791631369
