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https://issues.apache.org/jira/browse/LOG4J2-3452?focusedWorklogId=894785&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-894785
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ASF GitHub Bot logged work on LOG4J2-3452:
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Author: ASF GitHub Bot
Created on: 08/Dec/23 18:56
Start Date: 08/Dec/23 18:56
Worklog Time Spent: 10m
Work Description: ppkarwasz commented on PR #809:
URL: https://github.com/apache/logging-log4j2/pull/809#issuecomment-1847671971
@merkisoft,
The main point of @stefanvodita's PR is that `File.mkdirs` returns `false`
if the directory exits or a file system error occurs, we can not differentiate
the two cases. `Files.createDirectories` on the other hand throws an exception
only in the latter case.
I don't see anything wrong in adding a `Files.exists` call in front of
`Files.createDirectories`. You can create a PR for it.
**Remark**: with `Files.exists` you still need to add a "read" permission on
the log dir.
Issue Time Tracking
-------------------
Worklog Id: (was: 894785)
Time Spent: 40m (was: 0.5h)
> Race condition in FileUtils.mkdir()
> -----------------------------------
>
> Key: LOG4J2-3452
> URL: https://issues.apache.org/jira/browse/LOG4J2-3452
> Project: Log4j 2
> Issue Type: Bug
> Affects Versions: 2.13.0
> Reporter: Stefan Vodita
> Priority: Major
> Time Spent: 40m
> Remaining Estimate: 0h
>
> I noticed an error like:
> {{ERROR Unable to create file ...}}
> {{at org.apache.logging.log4j.core.util.FileUtils.mkdir(FileUtils.java:118)}}
>
> The error could be due to a race condition:
> {{Thread A: dir.exists() -> false}}
> {{Thread B: dir.exists() -> false}}
> {{Thread B: dir.mkdirs() -> succeeds}}
> {{Thread A: dir.mkdirs() -> throws exception}}
>
> I wrote a unit test which reproduces the error:
> {{public void testMkdirConcurrent() throws IOException {}}
> {{ final File file = new File("target/test/test");}}
> {{ for (int i = 0; i < 1000; i++) {}}
> {{ new Thread(() -> assertDoesNotThrow(() -> FileUtils.mkdir(file,
> true))).start();}}
> {{ org.apache.commons.io.FileUtils.deleteDirectory(file);}}
> {{}}}
>
> As a fix, we can use {{{}Files.createDirectories(){}}}, since this does the
> existence check and creation as one atomic operation.
>
> I will create a PR with the unit test and a fix.
>
>
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