Bug #32282: typo3temp/locks warning. unlink function returns warning - TYPO3 Core - TYPO3 Forge

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Bug #32282

closed

typo3temp/locks warning. unlink function returns warning

Added by Razakanirina almost 13 years ago. Updated about 6 years ago.

Status:

Closed

Priority:

Should have

Assignee:

Category:

Target version:

Start date:

2011-12-03

Due date:

% Done:

100%

Estimated time:

TYPO3 Version:

4.5

PHP Version:

5.3

Tags:

Complexity:

Is Regression:

Sprint Focus:

Description

php unlink() function returns a warning when the file does not exist.

Obtained warning:
---
Core: Error handler (FE): PHP Warning: unlink(/.../.../typo3temp/locks/107c9b0324ec9db67812eb6af3e78732) [<a href='function.unlink'>function.unlink</a>]: No such file or directory in /usr/local/src/typo3/typo3_src-4.5.8/t3lib/class.t3lib_lock.php line 210

We should test the $this->resource variable by file_exists() php function before unlinking.

if (unlink($this->resource) == FALSE) {

Files

T3X_user_locktest-0_0_0-z-201112201702.t3x (1.82 KB) T3X_user_locktest-0_0_0-z-201112201702.t3x

Helmut Hummel, 2011-12-20 17:05

Related issues 3 (0 open — 3 closed)

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Updated by Gerrit Code Review almost 13 years ago

Status changed from New to Under Review

Patch set 1 for branch master has been pushed to the review server.
It is available at http://review.typo3.org/7052

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Updated by Xavier Perseguers almost 13 years ago

I've seen this behaviour and I'm currently trying to figure out what the cause is. I suspect some race condition.

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Updated by Björn Pedersen almost 13 years ago

This is a race condition reported here already:
http://forge.typo3.org/issues/24342

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Updated by Xavier Perseguers almost 13 years ago

There is indeed a problem that appears when the lock file could not be acquired, as reported in this syslog (after slightly modifying Core to add additional information):

05-12-11 15:24 - cms: Locking: Failed to acquire lock: Lock file could not be created
(/path/to/typo3temp/locks/f288221509d8f33b8e85fbfd25731733)
05-12-11 15:24 - Core: Error handler (FE): PHP Warning: unlink(/path/to/typo3temp/locks/
f288221509d8f33b8e85fbfd25731733) [<a href='function.unlink'>function.unlink</a>]: No such
file or directory in /path/to/t3lib/class.t3lib_lock.php line 21

The non-acquired lock-file is then "unlinked" by taking for granted that it exists. By quickly digging into the code, I'd say that fixing that would require quite some refactoring of t3lib_lock, refactoring that is supposed to happen with #24342 but was forgotten (as not pushed forwards) for 4.6, thus hopefully something for 4.7.

Anyway, I would suggest to simply test for file existence before unlinking it but not hide the warning with an @ sign in front of unlink.

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Updated by Razakanirina almost 13 years ago

Does testing if file exists solve the race condition problem? Does it related to the php unlink() function?

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Updated by Helmut Hummel almost 13 years ago

Status changed from Under Review to Needs Feedback

For those who have problems with the unlink warning message:

What is your max_execution_time setting?

The only reace condition which is clearly there is because of deleting stale lock files.

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Updated by Helmut Hummel almost 13 years ago

File T3X_user_locktest-0_0_0-z-201112201702.t3x T3X_user_locktest-0_0_0-z-201112201702.t3x added

I added a small extension to reproduce the problem.

Install it, then execute the following command line:

wget -qO- "http://typo3.dev/index.php?eID=locktest&number=first" & sleep 2; wget -qO- "http://typo3.dev/index.php?eID=locktest&number=second"

The problem will occur, when the max_execution_time is relatively low (forced to be 1 second in the extension), but the request itself takes longer than the max_execution_time

This may well happen because max_execution_time only reflects the PHP script execution times but excludes the time that is consumed by single commands (like sleep or other system commands)

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Updated by Xavier Perseguers almost 13 years ago

What about adding the @ sign in front of unlink instead of testing with file_exists. I'd say that even if not "that clean", it will prevent perform 2 accesses for the file system in most cases...

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