Backport "Allow WASI to open directories without O_DIRECTORY" (#6163) #6283
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
…dealliance#6163) The `O_DIRECTORY` flag is a request that open should fail if the named path is not a directory. Opening a path which turns out to be a directory is not supposed to fail if this flag is not specified. However, wasi-common required callers to use it when opening directories. With this PR, we always open the path the same way whether or not the `O_DIRECTORY` flag is specified. However, after opening it, we `stat` it to check whether it turned out to be a directory, and determine which operations the file descriptor should support accordingly. In addition, we explicitly check whether the precondition defined by `O_DIRECTORY` is satisfied. On Windows, when opening a path which might be a directory using `CreateFile`, cap-primitives also removes the `FILE_SHARE_DELETE` mode. That means that if we implement WASI's `path_open` such that it always uses `CreateFile` on Windows, for both files and directories, then holding an open file handle prevents deletion of that file.
alexcrichton
approved these changes
Apr 25, 2023
|
Sure thing. Would you review the release notes I just wrote for this too? |
github-actions
bot
added
wasi
Subscribe to Label Actioncc @kubkon
This issue or pull request has been labeled: "wasi", "wasmtime:docs"
Thus the following users have been cc'd because of the following labels:
To subscribe or unsubscribe from this label, edit the |
alexcrichton
approved these changes
Apr 25, 2023
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
The
O_DIRECTORYflag is a request that open should fail if the named path is not a directory. Opening a path which turns out to be a directory is not supposed to fail if this flag is not specified. However, wasi-common required callers to use it when opening directories.With this PR, we always open the path the same way whether or not the
O_DIRECTORYflag is specified. However, after opening it, westatit to check whether it turned out to be a directory, and determine which operations the file descriptor should support accordingly. In addition, we explicitly check whether the precondition defined byO_DIRECTORYis satisfied.On Windows, when opening a path which might be a directory using
CreateFile, cap-primitives also removes theFILE_SHARE_DELETEmode. That means that if we implement WASI'spath_opensuch that it always usesCreateFileon Windows, for both files and directories, then holding an open file handle prevents deletion of that file.