bug #27668 [Lock] use 'r+' for fopen (fixes issue on Solaris) (fritzmg)
This PR was squashed before being merged into the 3.4 branch (closes #27668).
Discussion
----------
[Lock] use 'r+' for fopen (fixes issue on Solaris)
| Q | A
| ------------- | ---
| Branch? | 3.4 (also applicable to _LockHandler_ in 2.8 and 3.3)
| Bug fix? | yes
| New feature? | no
| BC breaks? | no
| Deprecations? | no
| Tests pass? | yes [1]
| Fixed tickets | -
| License | MIT
| Doc PR | -
We discovered a curious case on a specific hosting environment: the `FlockStorage` (or `LockHandler` in previous Symfony versions) could never get a file lock on **existing files**. So if you run a script for the first time and the lock file did not exist yet, the `FlockStorage` could get a lock on that file just fine. However on the second and subsequent runs, `FlockStorage` could _never_ get a file lock anymore. You can follow the discussion [here](https://github.com/contao/core-bundle/issues/1551) (if you speak German).
We have been using this little script to confirm the issue on the hosting environment:
```php
$fileName = __DIR__ . '/file.lock';
if (!$handle = @fopen($fileName, 'r')) {
$handle = fopen($fileName, 'x');
}
if (!$handle) {
echo "Could not open $fileName\n";
exit;
}
if (flock($handle, LOCK_EX | LOCK_NB)) {
echo "Got a lock on $fileName\n";
flock($handle, LOCK_UN | LOCK_NB);
} else {
echo "Could not get a lock on $fileName\n";
}
```
Whenever `file.lock` already existed prior to running the script, a lock could not be made.
After contacting the hosting provider's support on this they confirmed the issue and told us they are using **Solaris** instead of a Linux environment. And this is supposedly why it does not work. Instead you have to use `'r+'` instead of `'r'` for `fopen`.
I was able to confirm that changing from `'r'` to `'r+'` fixes the issue. However I am wondering who's actually at fault here. Is it Solaris? PHP? The compiled PHP version under Solaris? The hosting provider's operating system configuration?
### System information
```
uname -a
SunOS vlek 5.11 11.3 i86pc i386 i86pc Solaris
```
```
phpinfo:
SunOS localhost 5.10 Generic_150401-49 i86pc
```
```
php -v
PHP 7.2.5 (cli) (built: May 4 2018 12:57:43) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.2.0, Copyright (c) 1998-2018 Zend Technologies
```
### Footnotes
[1] Previously one failed test on the first run and two failing tests on the second run with the proposed changes:
```
1) Symfony\Component\Lock\Tests\Store\FlockStoreTest::testSaveSanitizeName
Symfony\Component\Lock\Exception\LockStorageException: fopen(C:\Users\[…]\AppData\Local\Temp/sf.-php-echo-hello-word-.Sz2dDSf.lock)
: failed to open stream: Permission denied
```
```
2) Symfony\Component\Lock\Tests\Store\FlockStoreTest::testSaveWithDifferentKeysOnSameResources
Symfony\Component\Lock\Exception\LockStorageException: fopen(C:\Users\[…]\AppData\Local\Temp/sf.Symfony-Component-Lock-Tests-Store-
AbstractStoreTest-testSaveWithDifferentKeysOnSameResources5b2b5f00872538.64807920.2u9bH+a.lock): failed to open stream: Permission denied
```
The latter failed both on the first run and on the second run.
After the [proposed changes](https://github.com/symfony/symfony/pull/27668#discussion_r197054198) from @nicolas-grekas everything works fine 👍
Commits
-------
9c9ae7d9c9
[Lock] use 'r+' for fopen (fixes issue on Solaris)
This commit is contained in:
commit
df0dba6cdf
@ -79,12 +79,12 @@ class FlockStore implements StoreInterface
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// Silence error reporting
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set_error_handler(function ($type, $msg) use (&$error) { $error = $msg; });
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if (!$handle = fopen($fileName, 'r')) {
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if (!$handle = fopen($fileName, 'r+') ?: fopen($fileName, 'r')) {
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if ($handle = fopen($fileName, 'x')) {
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chmod($fileName, 0444);
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} elseif (!$handle = fopen($fileName, 'r')) {
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} elseif (!$handle = fopen($fileName, 'r+') ?: fopen($fileName, 'r')) {
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usleep(100); // Give some time for chmod() to complete
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$handle = fopen($fileName, 'r');
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$handle = fopen($fileName, 'r+') ?: fopen($fileName, 'r');
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}
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}
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restore_error_handler();
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