JDK-8280004: DCmdArgument<jlong>::parse_value() should handle NULL input

[tstuefe]

Hi,

may I have eyes please on this simple fix (Sonarcloud-inspired) which sanitizes the error output of DCmdArgument::parse_value():

• since the input can be NULL, we should handle NULL
• we also limit parroting of invalid input to 64 chars max
• we also do not need a temporary RA buffer to assemble the output

Example output with patch, first a short, then a long invalid numeric parameter:

thomas@starfish:~$ jcmd Simple GC.class_histogram -parallel=hallo
399746:
java.lang.IllegalArgumentException: Integer parsing error in command argument '-parallel'. Could not parse: "hallo".
thomas@starfish:~$ jcmd Simple GC.class_histogram -parallel=hallo012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789
399746:
java.lang.IllegalArgumentException: Integer parsing error in command argument '-parallel'. Could not parse: "hallo01234567890123456789012345678901234567890123456789012345678...".

Thanks, Thomas

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• Change must be properly reviewed

Issue

• JDK-8280004: DCmdArgument::parse_value() should handle NULL input

Reviewers

• David Holmes (@dholmes-ora - Reviewer) ⚠️ Review applies to c016f79
• Matthias Baesken (@MBaesken - Reviewer) ⚠️ Review applies to 8af9413

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk pull/7079/head:pull/7079
$ git checkout pull/7079

Update a local copy of the PR:
$ git checkout pull/7079
$ git pull https://git.openjdk.java.net/jdk pull/7079/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 7079

View PR using the GUI difftool:
$ git pr show -t 7079

Using diff file

Download this PR as a diff file:
https://git.openjdk.java.net/jdk/pull/7079.diff

[bridgekeeper]

👋 Welcome back stuefe! 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]

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

• hotspot-runtime

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

• 02: Full - Incremental (a6ca495c)
• 01: Full - Incremental (8af94135)
• 00: Full (c016f795)

[dholmes-ora]

Hi Thomas,

Are you sure about the removal of the copying? I can't quite convince myself that the original string from the command line will still be allocated by the time the exception gets propagated and accessed.

Thanks,
David

[tstuefe]

Hi Thomas,

Are you sure about the removal of the copying? I can't quite convince myself that the original string from the command line will still be allocated by the time the exception gets propagated and accessed.

Thanks, David

Hi David,

the function calls Exceptions::fthrow, which calls os::vsnprintf right away and uses yet another temporary buffer, in that case, stack-based:

jdk/src/hotspot/share/utilities/exceptions.cpp

Lines 259 to 267 in 39f140a

	void Exceptions::fthrow(JavaThread* thread, const char* file, int line, Symbol* h_name, const char* format, ...) {
	const int max_msg_size = 1024;
	va_list ap;
	va_start(ap, format);
	char msg[max_msg_size];
	os::vsnprintf(msg, max_msg_size, format, ap);
	va_end(ap);
	_throw_msg(thread, file, line, h_name, msg);
	}

So this patch just moves the snprintf call two lines further down, and removes the need for one of the temp buffers. But it still resolved the exception text in the context of this function. Or am I misunderstanding you?

Cheers, Thomas

[dholmes-ora]

Thanks Thomas! I was too focused on the original string and didn't check that the exception code was going to make a copy anyway. There's likely multiple copies made on the way to the final String object.

[dholmes-ora]

Seems fine.

Thanks,
David

[openjdk]

@tstuefe 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:

8280004: DCmdArgument<jlong>::parse_value() should handle NULL input

Reviewed-by: dholmes, mbaesken

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 11 new commits pushed to the master branch:

• 178ac74: 8251466: test/java/io/File/GetXSpace.java fails on Windows with mapped network drives.
• a1d1e47: 8280823: Remove NULL check in DumpTimeClassInfo::is_excluded
• 094db1a: 8277948: AArch64: Print the correct native stack if -XX:+PreserveFramePointer when crash
• 7857405: 8280744: Allow SuppressWarnings to be used in all declaration contexts
• 40a2ce2: 8270476: Make floating-point test infrastructure more lambda and method reference friendly
• 6d242e4: 8280835: jdk/javadoc/tool/CheckManPageOptions.java depends on source hierarchy
• ece89c6: 8280366: (fs) Restore Files.createTempFile javadoc
• b94ebaa: 8280686: Remove Compile::print_method_impl
• a3a0dcd: 8280353: -XX:ArchiveClassesAtExit should print warning if base archive failed to load
• cab5905: 8280583: Always build NMT
• ... and 1 more: https://git.openjdk.java.net/jdk/compare/94380d0e464a491977ed2b5f1998a55cfe73c3c6...master

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.

[tstuefe]

Seems fine.

Thanks, David

Thank you David!

[MBaesken]

I think you might need to adjust the copyright year in the file; but otherwise it's fine,

[tstuefe]

Thanks @dholmes-ora and @MBaesken !

/integrate

[openjdk]

Going to push as commit 55f180f.
Since your change was applied there have been 11 commits pushed to the master branch:

• 178ac74: 8251466: test/java/io/File/GetXSpace.java fails on Windows with mapped network drives.
• a1d1e47: 8280823: Remove NULL check in DumpTimeClassInfo::is_excluded
• 094db1a: 8277948: AArch64: Print the correct native stack if -XX:+PreserveFramePointer when crash
• 7857405: 8280744: Allow SuppressWarnings to be used in all declaration contexts
• 40a2ce2: 8270476: Make floating-point test infrastructure more lambda and method reference friendly
• 6d242e4: 8280835: jdk/javadoc/tool/CheckManPageOptions.java depends on source hierarchy
• ece89c6: 8280366: (fs) Restore Files.createTempFile javadoc
• b94ebaa: 8280686: Remove Compile::print_method_impl
• a3a0dcd: 8280353: -XX:ArchiveClassesAtExit should print warning if base archive failed to load
• cab5905: 8280583: Always build NMT
• ... and 1 more: https://git.openjdk.java.net/jdk/compare/94380d0e464a491977ed2b5f1998a55cfe73c3c6...master

Your commit was automatically rebased without conflicts.

[openjdk]

@tstuefe Pushed as commit 55f180f.

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