8285445: cannot open file "NUL:"

[bplb]

Change the default value of the jdk.io.File.enableADS property to true.

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• Change must be properly reviewed
• Change requires a CSR request to be approved

Issues

• JDK-8285445: cannot open file "NUL:"
• JDK-8285500: cannot open file "NUL:" (CSR)

Reviewers

• Mikael Vidstedt (@vidmik - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk pull/8373/head:pull/8373
$ git checkout pull/8373

Update a local copy of the PR:
$ git checkout pull/8373
$ git pull https://git.openjdk.java.net/jdk pull/8373/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 8373

View PR using the GUI difftool:
$ git pr show -t 8373

Using diff file

Download this PR as a diff file:
https://git.openjdk.java.net/jdk/pull/8373.diff

[bridgekeeper]

👋 Welcome back bpb! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

@bplb The following label will be automatically applied to this pull request:

• core-libs

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

[mlbridge]

Webrevs

• 00: Full (8a2e1812)

[openjdk]

@bplb This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8285445: cannot open file "NUL:"

Reviewed-by: mikael

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 1 new commit pushed to the master branch:

• b10833b: 8285303: riscv: Incorrect register mask in call_native_base

Please see this link for an up-to-date comparison between the source branch of this pull request and the master branch.
As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[mlbridge]

Mailing list message from Bernd Eckenfels on core-libs-dev:

Is that really a needed fix? enabling ADS and less strict parsing might introduce vulnerability but on the other hand NUL: should be allowed for it is a drive style not a ADS.

I would also think the number of users who want use NUL: is smaller than the number of users who benefit from ADS being forbidden. Especially since \\.\NUL or NUL should already work.

Gruss
Bernd
--
http://bernd.eckenfels.net
________________________________
Von: core-libs-dev <core-libs-dev-retn at openjdk.java.net> im Auftrag von Brian Burkhalter <bpb at openjdk.java.net>
Gesendet: Saturday, April 23, 2022 3:20:02 AM
An: core-libs-dev at openjdk.java.net <core-libs-dev at openjdk.java.net>
Betreff: RFR: 8285445: cannot open file "NUL:"

Change the default value of the `jdk.io.File.enableADS` property to `true`.

-------------

Commit messages:
- 8285445: cannot open file "NUL:"

Changes: https://git.openjdk.java.net/jdk/pull/8373/files
Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8373&range=00
Issue: https://bugs.openjdk.java.net/browse/JDK-8285445
Stats: 57 lines in 2 files changed: 52 ins; 1 del; 4 mod
Patch: https://git.openjdk.java.net/jdk/pull/8373.diff
Fetch: git fetch https://git.openjdk.java.net/jdk pull/8373/head:pull/8373

PR: https://git.openjdk.java.net/jdk/pull/8373

[dmlloyd]

FWIW we fixed the same problem by simply using NUL instead of NUL:.

[AlanBateman]

FWIW we fixed the same problem by simply using NUL instead of NUL:.

Hopefully newer code can use OutputStream.nullOutputStream(). It's portable and avoids depending on these legacy Windows specific reserved names.

[bplb]

This topic will be examined further under JDK-8285511.

[bplb]

/integrate

[openjdk]

Going to push as commit 03cbb48.
Since your change was applied there have been 3 commits pushed to the master branch:

• e9d604a: 8285431: Assertion in NativeGSSContext constructor
• 357b1b1: 8242440: use separate, destroyable JavaVM instances per libgraal compiler thread
• b10833b: 8285303: riscv: Incorrect register mask in call_native_base

Your commit was automatically rebased without conflicts.

[openjdk]

@bplb Pushed as commit 03cbb48.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

[bplb]

/backport jdk18u

[dmlloyd]

FWIW we fixed the same problem by simply using NUL instead of NUL:.

Hopefully newer code can use OutputStream.nullOutputStream(). It's portable and avoids depending on these legacy Windows specific reserved names.

One possible advantage of having a "real" OS-supported null stream (in addition to its uses by the process subsystem) is that it could be used to efficiently drain bytes from things like sockets and pipes using transfer methods, assuming adequate JDK support. On Linux at least, the splice syscall is able to move bytes between socket and pipe buffers and into file buffers without copying them into user space. For /dev/null this means the bytes are discarded on the kernel side.