[2/3] Proper path resolution: add readlinkat functionality #2264
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This commit adds the `openat` functionality to `sys.FS`. On UNIX-like platforms, this is done with the `openat(2)` syscall. On Windows, this is done with [`NtCreateFile`][1]. This is the first in a series of commit that overhauls how paths are resolved. The wasi-filesystem spec now [describes][2] a path resolution implementation that uses `openat`. [1]: https://learn.microsoft.com/en-us/windows/win32/api/winternl/nf-winternl-ntcreatefile [2]: https://github.com/WebAssembly/wasi-filesystem/blob/main/path-resolution.md Signed-off-by: Yage Hu <[email protected]>
Signed-off-by: Yage Hu <[email protected]>
Signed-off-by: Yage Hu <[email protected]>
Signed-off-by: Yage Hu <[email protected]>
Signed-off-by: Yage Hu <[email protected]>
Signed-off-by: Yage Hu <[email protected]>
Signed-off-by: Yage Hu <[email protected]>
This commit adds the `ReadLinkAt` functionality needed to implement proper path resolution in WASI. On Linux, it's implemented by stringing together `fstatat` and `readlinkat(2)`. On Darwin, since `fstatat(2)` does not support the `AT_SYMLINK_` flag, we use `lstat(2)`. Signed-off-by: Yage Hu <[email protected]>
Signed-off-by: Yage Hu <[email protected]>
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This PR is the second in a series that will implement the path resolution algorithm described by wasi-filesystem. This PR currently targets the main branch and thus includes changes in part 1 (#2254). When #2254 is merged I'll rebase this PR.
This PR adds the
readlinkat(2)syscall to Linux and Darwin and the equivalent on Windows. This is needed to support the path resolution algorithm by expanding symlinks as we encounter them when resolving paths.