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Merge pull request #34009 from andrey-utkin/safe-config-update 

Make config file saving safe against write failures
This commit is contained in:
Côme Chilliet 2022-09-15 15:00:40 +02:00 committed by GitHub
parent c0c31bdc45 807c53b2ab
commit 1013c3bf66
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 30 additions and 26 deletions
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56
lib/private/Config.php
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@ -224,11 +224,6 @@ class Config {
continue;
}
// Try to acquire a file lock
if (!flock($filePointer, LOCK_SH)) {
throw new \Exception(sprintf('Could not acquire a shared lock on the config file %s', $file));
}
unset($CONFIG);
include $file;
if (!defined('PHPUNIT_RUN') && headers_sent()) {
@ -244,7 +239,6 @@ class Config {
}
// Close the file pointer and release the lock
flock($filePointer, LOCK_UN);
fclose($filePointer);
}
@ -256,8 +250,7 @@ class Config {
*
* Saves the config to the config file.
*
* @throws HintException If the config file cannot be written to
* @throws \Exception If no file lock can be acquired
* @throws HintException If the config file cannot be written to, etc
*/
private function writeData() {
$this->checkReadOnly();
@ -272,30 +265,41 @@ class Config {
$content .= var_export($this->cache, true);
$content .= ";\n";
touch($this->configFilePath);
$filePointer = fopen($this->configFilePath, 'r+');
// Prevent others not to read the config
chmod($this->configFilePath, 0640);
// File does not exist, this can happen when doing a fresh install
if (!is_resource($filePointer)) {
// tmpfile must be in the same filesystem for the rename() to be atomic
$tmpfile = tempnam(dirname($this->configFilePath), 'config.php.tmp.');
// dirname check is for PHP's fallback quirk
if (!$tmpfile || dirname($tmpfile) != dirname($this->configFilePath)) {
if ($tmpfile) {
unlink($tmpfile);
}
throw new HintException(
"Can't write into config directory!",
"Can't create temporary file in config directory!",
'This can usually be fixed by giving the webserver write access to the config directory.');
}
// Try to acquire a file lock
if (!flock($filePointer, LOCK_EX)) {
throw new \Exception(sprintf('Could not acquire an exclusive lock on the config file %s', $this->configFilePath));
chmod($tmpfile, 0640);
$filePointer = fopen($tmpfile, 'w');
if (!is_resource($filePointer)) {
throw new HintException(
"Failed to open temporary file in config directory for writing",
'Please report this to Nextcloud developers.');
}
// Write the config and release the lock
ftruncate($filePointer, 0);
fwrite($filePointer, $content);
fflush($filePointer);
flock($filePointer, LOCK_UN);
fclose($filePointer);
$write_ok = fwrite($filePointer, $content);
$close_ok = fclose($filePointer);
if (!$write_ok || !$close_ok) {
unlink($tmpfile);
throw new HintException(
"Failed to save temporary file in config directory",
'Please report this to Nextcloud developers.');
}
if (!rename($tmpfile, $this->configFilePath)) {
unlink($tmpfile);
throw new HintException(
"Failed to replace the config file with the new copy",
'Please report this to Nextcloud developers.');
}
if (function_exists('opcache_invalidate')) {
@opcache_invalidate($this->configFilePath, true);