FSFileBackend.php

Go to the documentation of this file.

<?php
use Shellbox\Shellbox;
use Wikimedia\AtEase\AtEase;
use Wikimedia\FileBackend\FileBackend;
use Wikimedia\Timestamp\ConvertibleTimestamp;
 
class FSFileBackend extends FileBackendStore {
    protected $usableDirCache;
 
    protected $basePath;
 
    protected $containerPaths;
 
    protected $dirMode;
    protected $fileMode;
    protected $fileOwner;
 
    protected $os;
    protected $currentUser;
 
    private $warningTrapStack = [];
 
    public function __construct( array $config ) {
        parent::__construct( $config );
 
        if ( PHP_OS_FAMILY === 'Windows' ) {
            $this->os = 'Windows';
        } elseif ( PHP_OS_FAMILY === 'BSD' || PHP_OS_FAMILY === 'Darwin' ) {
            $this->os = 'BSD';
        } else {
            $this->os = 'Linux';
        }
        // Remove any possible trailing slash from directories
        if ( isset( $config['basePath'] ) ) {
            $this->basePath = rtrim( $config['basePath'], '/' ); // remove trailing slash
        } else {
            $this->basePath = null; // none; containers must have explicit paths
        }
 
        $this->containerPaths = [];
        foreach ( ( $config['containerPaths'] ?? [] ) as $container => $fsPath ) {
            $this->containerPaths[$container] = rtrim( $fsPath, '/' ); // remove trailing slash
        }
 
        $this->fileMode = $config['fileMode'] ?? 0644;
        $this->dirMode = $config['directoryMode'] ?? 0777;
        if ( isset( $config['fileOwner'] ) && function_exists( 'posix_getuid' ) ) {
            $this->fileOwner = $config['fileOwner'];
            // Cache this, assuming it doesn't change
            $this->currentUser = posix_getpwuid( posix_getuid() )['name'];
        }
 
        $this->usableDirCache = new MapCacheLRU( self::CACHE_CHEAP_SIZE );
    }
 
    public function getFeatures() {
        return self::ATTR_UNICODE_PATHS;
    }
 
    protected function resolveContainerPath( $container, $relStoragePath ) {
        // Check that container has a root directory
        if ( isset( $this->containerPaths[$container] ) || isset( $this->basePath ) ) {
            // Check for sensible relative paths (assume the base paths are OK)
            if ( $this->isLegalRelPath( $relStoragePath ) ) {
                return $relStoragePath;
            }
        }
 
        return null; // invalid
    }
 
    protected function isLegalRelPath( $fsPath ) {
        // Check for file names longer than 255 chars
        if ( preg_match( '![^/]{256}!', $fsPath ) ) { // ext3/NTFS
            return false;
        }
        if ( $this->os === 'Windows' ) { // NTFS
            return !preg_match( '![:*?"<>|]!', $fsPath );
        } else {
            return true;
        }
    }
 
    protected function containerFSRoot( $shortCont, $fullCont ) {
        if ( isset( $this->containerPaths[$shortCont] ) ) {
            return $this->containerPaths[$shortCont];
        } elseif ( isset( $this->basePath ) ) {
            return "{$this->basePath}/{$fullCont}";
        }
 
        return null; // no container base path defined
    }
 
    protected function resolveToFSPath( $storagePath ) {
        [ $fullCont, $relPath ] = $this->resolveStoragePathReal( $storagePath );
        if ( $relPath === null ) {
            return null; // invalid
        }
        [ , $shortCont, ] = FileBackend::splitStoragePath( $storagePath );
        $fsPath = $this->containerFSRoot( $shortCont, $fullCont ); // must be valid
        if ( $relPath != '' ) {
            $fsPath .= "/{$relPath}";
        }
 
        return $fsPath;
    }
 
    public function isPathUsableInternal( $storagePath ) {
        $fsPath = $this->resolveToFSPath( $storagePath );
        if ( $fsPath === null ) {
            return false; // invalid
        }
 
        if ( $this->fileOwner !== null && $this->currentUser !== $this->fileOwner ) {
            trigger_error( __METHOD__ . ": PHP process owner is not '{$this->fileOwner}'." );
            return false;
        }
 
        $fsDirectory = dirname( $fsPath );
        $usable = $this->usableDirCache->get( $fsDirectory, MapCacheLRU::TTL_PROC_SHORT );
        if ( $usable === null ) {
            AtEase::suppressWarnings();
            $usable = is_dir( $fsDirectory ) && is_writable( $fsDirectory );
            AtEase::restoreWarnings();
            $this->usableDirCache->set( $fsDirectory, $usable ? 1 : 0 );
        }
 
        return $usable;
    }
 
    protected function doCreateInternal( array $params ) {
        $status = $this->newStatus();
 
        $fsDstPath = $this->resolveToFSPath( $params['dst'] );
        if ( $fsDstPath === null ) {
            $status->fatal( 'backend-fail-invalidpath', $params['dst'] );
 
            return $status;
        }
 
        if ( !empty( $params['async'] ) ) { // deferred
            $tempFile = $this->newTempFileWithContent( $params );
            if ( !$tempFile ) {
                $status->fatal( 'backend-fail-create', $params['dst'] );
 
                return $status;
            }
            $cmd = $this->makeCopyCommand( $tempFile->getPath(), $fsDstPath, false );
            $handler = function ( $errors, StatusValue $status, array $params, $cmd ) {
                if ( $errors !== '' && !( $this->os === 'Windows' && $errors[0] === " " ) ) {
                    $status->fatal( 'backend-fail-create', $params['dst'] );
                    trigger_error( "$cmd\n$errors", E_USER_WARNING ); // command output
                }
            };
            $status->value = new FSFileOpHandle( $this, $params, $handler, $cmd );
            $tempFile->bind( $status->value );
        } else { // immediate write
            $created = false;
            // Use fwrite+rename since (a) this clears xattrs, (b) threads still reading the old
            // inode are unaffected since it writes to a new inode, and (c) new threads reading
            // the file will either totally see the old version or totally see the new version
            $fsStagePath = $this->makeStagingPath( $fsDstPath );
            $this->trapWarningsIgnoringNotFound();
            $stageHandle = fopen( $fsStagePath, 'xb' );
            if ( $stageHandle ) {
                $bytes = fwrite( $stageHandle, $params['content'] );
                $created = ( $bytes === strlen( $params['content'] ) );
                fclose( $stageHandle );
                $created = $created ? rename( $fsStagePath, $fsDstPath ) : false;
            }
            $hadError = $this->untrapWarnings();
            if ( $hadError || !$created ) {
                $status->fatal( 'backend-fail-create', $params['dst'] );
 
                return $status;
            }
            $this->chmod( $fsDstPath );
        }
 
        return $status;
    }
 
    protected function doStoreInternal( array $params ) {
        $status = $this->newStatus();
 
        $fsSrcPath = $params['src']; // file system path
        $fsDstPath = $this->resolveToFSPath( $params['dst'] );
        if ( $fsDstPath === null ) {
            $status->fatal( 'backend-fail-invalidpath', $params['dst'] );
 
            return $status;
        }
 
        if ( $fsSrcPath === $fsDstPath ) {
            $status->fatal( 'backend-fail-internal', $this->name );
 
            return $status;
        }
 
        if ( !empty( $params['async'] ) ) { // deferred
            $cmd = $this->makeCopyCommand( $fsSrcPath, $fsDstPath, false );
            $handler = function ( $errors, StatusValue $status, array $params, $cmd ) {
                if ( $errors !== '' && !( $this->os === 'Windows' && $errors[0] === " " ) ) {
                    $status->fatal( 'backend-fail-store', $params['src'], $params['dst'] );
                    trigger_error( "$cmd\n$errors", E_USER_WARNING ); // command output
                }
            };
            $status->value = new FSFileOpHandle( $this, $params, $handler, $cmd );
        } else { // immediate write
            $stored = false;
            // Use fwrite+rename since (a) this clears xattrs, (b) threads still reading the old
            // inode are unaffected since it writes to a new inode, and (c) new threads reading
            // the file will either totally see the old version or totally see the new version
            $fsStagePath = $this->makeStagingPath( $fsDstPath );
            $this->trapWarningsIgnoringNotFound();
            $srcHandle = fopen( $fsSrcPath, 'rb' );
            if ( $srcHandle ) {
                $stageHandle = fopen( $fsStagePath, 'xb' );
                if ( $stageHandle ) {
                    $bytes = stream_copy_to_stream( $srcHandle, $stageHandle );
                    $stored = ( $bytes !== false && $bytes === fstat( $srcHandle )['size'] );
                    fclose( $stageHandle );
                    $stored = $stored ? rename( $fsStagePath, $fsDstPath ) : false;
                }
                fclose( $srcHandle );
            }
            $hadError = $this->untrapWarnings();
            if ( $hadError || !$stored ) {
                $status->fatal( 'backend-fail-store', $params['src'], $params['dst'] );
 
                return $status;
            }
            $this->chmod( $fsDstPath );
        }
 
        return $status;
    }
 
    protected function doCopyInternal( array $params ) {
        $status = $this->newStatus();
 
        $fsSrcPath = $this->resolveToFSPath( $params['src'] );
        if ( $fsSrcPath === null ) {
            $status->fatal( 'backend-fail-invalidpath', $params['src'] );
 
            return $status;
        }
 
        $fsDstPath = $this->resolveToFSPath( $params['dst'] );
        if ( $fsDstPath === null ) {
            $status->fatal( 'backend-fail-invalidpath', $params['dst'] );
 
            return $status;
        }
 
        if ( $fsSrcPath === $fsDstPath ) {
            return $status; // no-op
        }
 
        $ignoreMissing = !empty( $params['ignoreMissingSource'] );
 
        if ( !empty( $params['async'] ) ) { // deferred
            $cmd = $this->makeCopyCommand( $fsSrcPath, $fsDstPath, $ignoreMissing );
            $handler = function ( $errors, StatusValue $status, array $params, $cmd ) {
                if ( $errors !== '' && !( $this->os === 'Windows' && $errors[0] === " " ) ) {
                    $status->fatal( 'backend-fail-copy', $params['src'], $params['dst'] );
                    trigger_error( "$cmd\n$errors", E_USER_WARNING ); // command output
                }
            };
            $status->value = new FSFileOpHandle( $this, $params, $handler, $cmd );
        } else { // immediate write
            $copied = false;
            // Use fwrite+rename since (a) this clears xattrs, (b) threads still reading the old
            // inode are unaffected since it writes to a new inode, and (c) new threads reading
            // the file will either totally see the old version or totally see the new version
            $fsStagePath = $this->makeStagingPath( $fsDstPath );
            $this->trapWarningsIgnoringNotFound();
            $srcHandle = fopen( $fsSrcPath, 'rb' );
            if ( $srcHandle ) {
                $stageHandle = fopen( $fsStagePath, 'xb' );
                if ( $stageHandle ) {
                    $bytes = stream_copy_to_stream( $srcHandle, $stageHandle );
                    $copied = ( $bytes !== false && $bytes === fstat( $srcHandle )['size'] );
                    fclose( $stageHandle );
                    $copied = $copied ? rename( $fsStagePath, $fsDstPath ) : false;
                }
                fclose( $srcHandle );
            }
            $hadError = $this->untrapWarnings();
            if ( $hadError || ( !$copied && !$ignoreMissing ) ) {
                $status->fatal( 'backend-fail-copy', $params['src'], $params['dst'] );
 
                return $status;
            }
            if ( $copied ) {
                $this->chmod( $fsDstPath );
            }
        }
 
        return $status;
    }
 
    protected function doMoveInternal( array $params ) {
        $status = $this->newStatus();
 
        $fsSrcPath = $this->resolveToFSPath( $params['src'] );
        if ( $fsSrcPath === null ) {
            $status->fatal( 'backend-fail-invalidpath', $params['src'] );
 
            return $status;
        }
 
        $fsDstPath = $this->resolveToFSPath( $params['dst'] );
        if ( $fsDstPath === null ) {
            $status->fatal( 'backend-fail-invalidpath', $params['dst'] );
 
            return $status;
        }
 
        if ( $fsSrcPath === $fsDstPath ) {
            return $status; // no-op
        }
 
        $ignoreMissing = !empty( $params['ignoreMissingSource'] );
 
        if ( !empty( $params['async'] ) ) { // deferred
            $cmd = $this->makeMoveCommand( $fsSrcPath, $fsDstPath, $ignoreMissing );
            $handler = function ( $errors, StatusValue $status, array $params, $cmd ) {
                if ( $errors !== '' && !( $this->os === 'Windows' && $errors[0] === " " ) ) {
                    $status->fatal( 'backend-fail-move', $params['src'], $params['dst'] );
                    trigger_error( "$cmd\n$errors", E_USER_WARNING ); // command output
                }
            };
            $status->value = new FSFileOpHandle( $this, $params, $handler, $cmd );
        } else { // immediate write
            // Use rename() here since (a) this clears xattrs, (b) any threads still reading the
            // old inode are unaffected since it writes to a new inode, and (c) this is fast and
            // atomic within a file system volume (as is normally the case)
            $this->trapWarningsIgnoringNotFound();
            $moved = rename( $fsSrcPath, $fsDstPath );
            $hadError = $this->untrapWarnings();
            if ( $hadError || ( !$moved && !$ignoreMissing ) ) {
                $status->fatal( 'backend-fail-move', $params['src'], $params['dst'] );
 
                return $status;
            }
        }
 
        return $status;
    }
 
    protected function doDeleteInternal( array $params ) {
        $status = $this->newStatus();
 
        $fsSrcPath = $this->resolveToFSPath( $params['src'] );
        if ( $fsSrcPath === null ) {
            $status->fatal( 'backend-fail-invalidpath', $params['src'] );
 
            return $status;
        }
 
        $ignoreMissing = !empty( $params['ignoreMissingSource'] );
 
        if ( !empty( $params['async'] ) ) { // deferred
            $cmd = $this->makeUnlinkCommand( $fsSrcPath, $ignoreMissing );
            $handler = function ( $errors, StatusValue $status, array $params, $cmd ) {
                if ( $errors !== '' && !( $this->os === 'Windows' && $errors[0] === " " ) ) {
                    $status->fatal( 'backend-fail-delete', $params['src'] );
                    trigger_error( "$cmd\n$errors", E_USER_WARNING ); // command output
                }
            };
            $status->value = new FSFileOpHandle( $this, $params, $handler, $cmd );
        } else { // immediate write
            $this->trapWarningsIgnoringNotFound();
            $deleted = unlink( $fsSrcPath );
            $hadError = $this->untrapWarnings();
            if ( $hadError || ( !$deleted && !$ignoreMissing ) ) {
                $status->fatal( 'backend-fail-delete', $params['src'] );
 
                return $status;
            }
        }
 
        return $status;
    }
 
    protected function doPrepareInternal( $fullCont, $dirRel, array $params ) {
        $status = $this->newStatus();
        [ , $shortCont, ] = FileBackend::splitStoragePath( $params['dir'] );
        $contRoot = $this->containerFSRoot( $shortCont, $fullCont ); // must be valid
        $fsDirectory = ( $dirRel != '' ) ? "{$contRoot}/{$dirRel}" : $contRoot;
        // Create the directory and its parents as needed...
        $created = false;
        AtEase::suppressWarnings();
        $alreadyExisted = is_dir( $fsDirectory ); // already there?
        if ( !$alreadyExisted ) {
            $created = mkdir( $fsDirectory, $this->dirMode, true );
            if ( !$created ) {
                $alreadyExisted = is_dir( $fsDirectory ); // another thread made it?
            }
        }
        $isWritable = $created ?: is_writable( $fsDirectory ); // assume writable if created here
        AtEase::restoreWarnings();
        if ( !$alreadyExisted && !$created ) {
            $this->logger->error( __METHOD__ . ": cannot create directory $fsDirectory" );
            $status->fatal( 'directorycreateerror', $params['dir'] ); // fails on races
        } elseif ( !$isWritable ) {
            $this->logger->error( __METHOD__ . ": directory $fsDirectory is read-only" );
            $status->fatal( 'directoryreadonlyerror', $params['dir'] );
        }
        // Respect any 'noAccess' or 'noListing' flags...
        if ( $created ) {
            $status->merge( $this->doSecureInternal( $fullCont, $dirRel, $params ) );
        }
 
        if ( $status->isGood() ) {
            $this->usableDirCache->set( $fsDirectory, 1 );
        }
 
        return $status;
    }
 
    protected function doSecureInternal( $fullCont, $dirRel, array $params ) {
        $status = $this->newStatus();
        [ , $shortCont, ] = FileBackend::splitStoragePath( $params['dir'] );
        $contRoot = $this->containerFSRoot( $shortCont, $fullCont ); // must be valid
        $fsDirectory = ( $dirRel != '' ) ? "{$contRoot}/{$dirRel}" : $contRoot;
        // Seed new directories with a blank index.html, to prevent crawling...
        if ( !empty( $params['noListing'] ) && !is_file( "{$fsDirectory}/index.html" ) ) {
            $this->trapWarnings();
            $bytes = file_put_contents( "{$fsDirectory}/index.html", $this->indexHtmlPrivate() );
            $this->untrapWarnings();
            if ( $bytes === false ) {
                $status->fatal( 'backend-fail-create', $params['dir'] . '/index.html' );
            }
        }
        // Add a .htaccess file to the root of the container...
        if ( !empty( $params['noAccess'] ) && !is_file( "{$contRoot}/.htaccess" ) ) {
            AtEase::suppressWarnings();
            $bytes = file_put_contents( "{$contRoot}/.htaccess", $this->htaccessPrivate() );
            AtEase::restoreWarnings();
            if ( $bytes === false ) {
                $storeDir = "mwstore://{$this->name}/{$shortCont}";
                $status->fatal( 'backend-fail-create', "{$storeDir}/.htaccess" );
            }
        }
 
        return $status;
    }
 
    protected function doPublishInternal( $fullCont, $dirRel, array $params ) {
        $status = $this->newStatus();
        [ , $shortCont, ] = FileBackend::splitStoragePath( $params['dir'] );
        $contRoot = $this->containerFSRoot( $shortCont, $fullCont ); // must be valid
        $fsDirectory = ( $dirRel != '' ) ? "{$contRoot}/{$dirRel}" : $contRoot;
        // Unseed new directories with a blank index.html, to allow crawling...
        if ( !empty( $params['listing'] ) && is_file( "{$fsDirectory}/index.html" ) ) {
            $exists = ( file_get_contents( "{$fsDirectory}/index.html" ) === $this->indexHtmlPrivate() );
            if ( $exists && !$this->unlink( "{$fsDirectory}/index.html" ) ) { // reverse secure()
                $status->fatal( 'backend-fail-delete', $params['dir'] . '/index.html' );
            }
        }
        // Remove the .htaccess file from the root of the container...
        if ( !empty( $params['access'] ) && is_file( "{$contRoot}/.htaccess" ) ) {
            $exists = ( file_get_contents( "{$contRoot}/.htaccess" ) === $this->htaccessPrivate() );
            if ( $exists && !$this->unlink( "{$contRoot}/.htaccess" ) ) { // reverse secure()
                $storeDir = "mwstore://{$this->name}/{$shortCont}";
                $status->fatal( 'backend-fail-delete', "{$storeDir}/.htaccess" );
            }
        }
 
        return $status;
    }
 
    protected function doCleanInternal( $fullCont, $dirRel, array $params ) {
        $status = $this->newStatus();
        [ , $shortCont, ] = FileBackend::splitStoragePath( $params['dir'] );
        $contRoot = $this->containerFSRoot( $shortCont, $fullCont ); // must be valid
        $fsDirectory = ( $dirRel != '' ) ? "{$contRoot}/{$dirRel}" : $contRoot;
 
        $this->rmdir( $fsDirectory );
 
        return $status;
    }
 
    protected function doGetFileStat( array $params ) {
        $fsSrcPath = $this->resolveToFSPath( $params['src'] );
        if ( $fsSrcPath === null ) {
            return self::RES_ERROR; // invalid storage path
        }
 
        $this->trapWarnings(); // don't trust 'false' if there were errors
        $stat = is_file( $fsSrcPath ) ? stat( $fsSrcPath ) : false; // regular files only
        $hadError = $this->untrapWarnings();
 
        if ( is_array( $stat ) ) {
            $ct = new ConvertibleTimestamp( $stat['mtime'] );
 
            return [
                'mtime' => $ct->getTimestamp( TS_MW ),
                'size' => $stat['size']
            ];
        }
 
        return $hadError ? self::RES_ERROR : self::RES_ABSENT;
    }
 
    protected function doClearCache( array $paths = null ) {
        if ( is_array( $paths ) ) {
            foreach ( $paths as $path ) {
                $fsPath = $this->resolveToFSPath( $path );
                if ( $fsPath !== null ) {
                    clearstatcache( true, $fsPath );
                    $this->usableDirCache->clear( $fsPath );
                }
            }
        } else {
            clearstatcache( true ); // clear the PHP file stat cache
            $this->usableDirCache->clear();
        }
    }
 
    protected function doDirectoryExists( $fullCont, $dirRel, array $params ) {
        [ , $shortCont, ] = FileBackend::splitStoragePath( $params['dir'] );
        $contRoot = $this->containerFSRoot( $shortCont, $fullCont ); // must be valid
        $fsDirectory = ( $dirRel != '' ) ? "{$contRoot}/{$dirRel}" : $contRoot;
 
        $this->trapWarnings(); // don't trust 'false' if there were errors
        $exists = is_dir( $fsDirectory );
        $hadError = $this->untrapWarnings();
 
        return $hadError ? self::RES_ERROR : $exists;
    }
 
    public function getDirectoryListInternal( $fullCont, $dirRel, array $params ) {
        [ , $shortCont, ] = FileBackend::splitStoragePath( $params['dir'] );
        $contRoot = $this->containerFSRoot( $shortCont, $fullCont ); // must be valid
        $fsDirectory = ( $dirRel != '' ) ? "{$contRoot}/{$dirRel}" : $contRoot;
 
        $list = new FSFileBackendDirList( $fsDirectory, $params );
        $error = $list->getLastError();
        if ( $error !== null ) {
            if ( $this->isFileNotFoundError( $error ) ) {
                $this->logger->info( __METHOD__ . ": non-existant directory: '$fsDirectory'" );
 
                return []; // nothing under this dir
            } elseif ( is_dir( $fsDirectory ) ) {
                $this->logger->warning( __METHOD__ . ": unreadable directory: '$fsDirectory'" );
 
                return self::RES_ERROR; // bad permissions?
            } else {
                $this->logger->warning( __METHOD__ . ": unreachable directory: '$fsDirectory'" );
 
                return self::RES_ERROR;
            }
        }
 
        return $list;
    }
 
    public function getFileListInternal( $fullCont, $dirRel, array $params ) {
        [ , $shortCont, ] = FileBackend::splitStoragePath( $params['dir'] );
        $contRoot = $this->containerFSRoot( $shortCont, $fullCont ); // must be valid
        $fsDirectory = ( $dirRel != '' ) ? "{$contRoot}/{$dirRel}" : $contRoot;
 
        $list = new FSFileBackendFileList( $fsDirectory, $params );
        $error = $list->getLastError();
        if ( $error !== null ) {
            if ( $this->isFileNotFoundError( $error ) ) {
                $this->logger->info( __METHOD__ . ": non-existent directory: '$fsDirectory'" );
 
                return []; // nothing under this dir
            } elseif ( is_dir( $fsDirectory ) ) {
                $this->logger->warning( __METHOD__ .
                    ": unreadable directory: '$fsDirectory': $error" );
 
                return self::RES_ERROR; // bad permissions?
            } else {
                $this->logger->warning( __METHOD__ .
                    ": unreachable directory: '$fsDirectory': $error" );
 
                return self::RES_ERROR;
            }
        }
 
        return $list;
    }
 
    protected function doGetLocalReferenceMulti( array $params ) {
        $fsFiles = []; // (path => FSFile)
 
        foreach ( $params['srcs'] as $src ) {
            $source = $this->resolveToFSPath( $src );
            if ( $source === null ) {
                $fsFiles[$src] = self::RES_ERROR; // invalid path
                continue;
            }
 
            $this->trapWarnings(); // don't trust 'false' if there were errors
            $isFile = is_file( $source ); // regular files only
            $hadError = $this->untrapWarnings();
 
            if ( $isFile ) {
                $fsFiles[$src] = new FSFile( $source );
            } elseif ( $hadError ) {
                $fsFiles[$src] = self::RES_ERROR;
            } else {
                $fsFiles[$src] = self::RES_ABSENT;
            }
        }
 
        return $fsFiles;
    }
 
    protected function doGetLocalCopyMulti( array $params ) {
        $tmpFiles = []; // (path => TempFSFile)
 
        foreach ( $params['srcs'] as $src ) {
            $source = $this->resolveToFSPath( $src );
            if ( $source === null ) {
                $tmpFiles[$src] = self::RES_ERROR; // invalid path
                continue;
            }
            // Create a new temporary file with the same extension...
            $ext = FileBackend::extensionFromPath( $src );
            $tmpFile = $this->tmpFileFactory->newTempFSFile( 'localcopy_', $ext );
            if ( !$tmpFile ) {
                $tmpFiles[$src] = self::RES_ERROR;
                continue;
            }
 
            $tmpPath = $tmpFile->getPath();
            // Copy the source file over the temp file
            $this->trapWarnings(); // don't trust 'false' if there were errors
            $isFile = is_file( $source ); // regular files only
            $copySuccess = $isFile ? copy( $source, $tmpPath ) : false;
            $hadError = $this->untrapWarnings();
 
            if ( $copySuccess ) {
                $this->chmod( $tmpPath );
                $tmpFiles[$src] = $tmpFile;
            } elseif ( $hadError ) {
                $tmpFiles[$src] = self::RES_ERROR; // copy failed
            } else {
                $tmpFiles[$src] = self::RES_ABSENT;
            }
        }
 
        return $tmpFiles;
    }
 
    protected function directoriesAreVirtual() {
        return false;
    }
 
    protected function doExecuteOpHandlesInternal( array $fileOpHandles ) {
        $statuses = [];
 
        $pipes = [];
        foreach ( $fileOpHandles as $index => $fileOpHandle ) {
            $pipes[$index] = popen( $fileOpHandle->cmd, 'r' );
        }
 
        $errs = [];
        foreach ( $pipes as $index => $pipe ) {
            // Result will be empty on success in *NIX. On Windows,
            // it may be something like "        1 file(s) [copied|moved].".
            $errs[$index] = stream_get_contents( $pipe );
            fclose( $pipe );
        }
 
        foreach ( $fileOpHandles as $index => $fileOpHandle ) {
            $status = $this->newStatus();
            $function = $fileOpHandle->callback;
            $function( $errs[$index], $status, $fileOpHandle->params, $fileOpHandle->cmd );
            $statuses[$index] = $status;
        }
 
        return $statuses;
    }
 
    private function makeStagingPath( $fsPath ) {
        $time = dechex( time() ); // make it easy to find old orphans
        $hash = \Wikimedia\base_convert( md5( basename( $fsPath ) ), 16, 36, 25 );
        $unique = \Wikimedia\base_convert( bin2hex( random_bytes( 16 ) ), 16, 36, 25 );
 
        return dirname( $fsPath ) . "/.{$time}_{$hash}_{$unique}.tmpfsfile";
    }
 
    private function makeCopyCommand( $fsSrcPath, $fsDstPath, $ignoreMissing ) {
        // Use copy+rename since (a) this clears xattrs, (b) threads still reading the old
        // inode are unaffected since it writes to a new inode, and (c) new threads reading
        // the file will either totally see the old version or totally see the new version
        $fsStagePath = $this->makeStagingPath( $fsDstPath );
        $encSrc = Shellbox::escape( $this->cleanPathSlashes( $fsSrcPath ) );
        $encStage = Shellbox::escape( $this->cleanPathSlashes( $fsStagePath ) );
        $encDst = Shellbox::escape( $this->cleanPathSlashes( $fsDstPath ) );
        if ( $this->os === 'Windows' ) {
            // https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/copy
            // https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/move
            $cmdWrite = "COPY /B /Y $encSrc $encStage 2>&1 && MOVE /Y $encStage $encDst 2>&1";
            $cmd = $ignoreMissing ? "IF EXIST $encSrc $cmdWrite" : $cmdWrite;
        } else {
            // https://manpages.debian.org/buster/coreutils/cp.1.en.html
            // https://manpages.debian.org/buster/coreutils/mv.1.en.html
            $cmdWrite = "cp $encSrc $encStage 2>&1 && mv $encStage $encDst 2>&1";
            $cmd = $ignoreMissing ? "test -f $encSrc && $cmdWrite" : $cmdWrite;
            // Clean up permissions on any newly created destination file
            $octalPermissions = '0' . decoct( $this->fileMode );
            if ( strlen( $octalPermissions ) == 4 ) {
                $cmd .= " && chmod $octalPermissions $encDst 2>/dev/null";
            }
        }
 
        return $cmd;
    }
 
    private function makeMoveCommand( $fsSrcPath, $fsDstPath, $ignoreMissing = false ) {
        // https://manpages.debian.org/buster/coreutils/mv.1.en.html
        // https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/move
        $encSrc = Shellbox::escape( $this->cleanPathSlashes( $fsSrcPath ) );
        $encDst = Shellbox::escape( $this->cleanPathSlashes( $fsDstPath ) );
        if ( $this->os === 'Windows' ) {
            $writeCmd = "MOVE /Y $encSrc $encDst 2>&1";
            $cmd = $ignoreMissing ? "IF EXIST $encSrc $writeCmd" : $writeCmd;
        } else {
            $writeCmd = "mv -f $encSrc $encDst 2>&1";
            $cmd = $ignoreMissing ? "test -f $encSrc && $writeCmd" : $writeCmd;
        }
 
        return $cmd;
    }
 
    private function makeUnlinkCommand( $fsPath, $ignoreMissing = false ) {
        // https://manpages.debian.org/buster/coreutils/rm.1.en.html
        // https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/del
        $encSrc = Shellbox::escape( $this->cleanPathSlashes( $fsPath ) );
        if ( $this->os === 'Windows' ) {
            $writeCmd = "DEL /Q $encSrc 2>&1";
            $cmd = $ignoreMissing ? "IF EXIST $encSrc $writeCmd" : $writeCmd;
        } else {
            $cmd = $ignoreMissing ? "rm -f $encSrc 2>&1" : "rm $encSrc 2>&1";
        }
 
        return $cmd;
    }
 
    protected function chmod( $fsPath ) {
        if ( $this->os === 'Windows' ) {
            return true;
        }
 
        AtEase::suppressWarnings();
        $ok = chmod( $fsPath, $this->fileMode );
        AtEase::restoreWarnings();
 
        return $ok;
    }
 
    protected function unlink( $fsPath ) {
        AtEase::suppressWarnings();
        $ok = unlink( $fsPath );
        AtEase::restoreWarnings();
        clearstatcache( true, $fsPath );
 
        return $ok;
    }
 
    protected function rmdir( $fsDirectory ) {
        AtEase::suppressWarnings();
        $ok = rmdir( $fsDirectory ); // remove directory if empty
        AtEase::restoreWarnings();
        clearstatcache( true, $fsDirectory );
 
        return $ok;
    }
 
    protected function newTempFileWithContent( array $params ) {
        $tempFile = $this->tmpFileFactory->newTempFSFile( 'create_', 'tmp' );
        if ( !$tempFile ) {
            return null;
        }
 
        AtEase::suppressWarnings();
        if ( file_put_contents( $tempFile->getPath(), $params['content'] ) === false ) {
            $tempFile = null;
        }
        AtEase::restoreWarnings();
 
        return $tempFile;
    }
 
    protected function indexHtmlPrivate() {
        return '';
    }
 
    protected function htaccessPrivate() {
        return "Require all denied\n";
    }
 
    protected function cleanPathSlashes( $fsPath ) {
        return ( $this->os === 'Windows' ) ? strtr( $fsPath, '/', '\\' ) : $fsPath;
    }
 
    protected function trapWarnings( $regexIgnore = null ) {
        $this->warningTrapStack[] = false;
        set_error_handler( function ( $errno, $errstr ) use ( $regexIgnore ) {
            if ( $regexIgnore === null || !preg_match( $regexIgnore, $errstr ) ) {
                $this->logger->error( $errstr );
                $this->warningTrapStack[count( $this->warningTrapStack ) - 1] = true;
            }
            return true; // suppress from PHP handler
        }, E_WARNING );
    }
 
    protected function trapWarningsIgnoringNotFound() {
        $this->trapWarnings( $this->getFileNotFoundRegex() );
    }
 
    protected function untrapWarnings() {
        restore_error_handler();
 
        return array_pop( $this->warningTrapStack );
    }
 
    protected function getFileNotFoundRegex() {
        static $regex;
        if ( $regex === null ) {
            // "No such file or directory": string literal in spl_directory.c etc.
            $alternatives = [ ': No such file or directory' ];
            if ( $this->os === 'Windows' ) {
                // 2 = The system cannot find the file specified.
                // 3 = The system cannot find the path specified.
                $alternatives[] = ' \‍(code: [23]\‍)';
            }
            if ( function_exists( 'pcntl_strerror' ) ) {
                $alternatives[] = preg_quote( ': ' . pcntl_strerror( 2 ), '/' );
            } elseif ( function_exists( 'socket_strerror' ) && defined( 'SOCKET_ENOENT' ) ) {
                $alternatives[] = preg_quote( ': ' . socket_strerror( SOCKET_ENOENT ), '/' );
            }
            $regex = '/(' . implode( '|', $alternatives ) . ')$/';
        }
        return $regex;
    }
 
    protected function isFileNotFoundError( $error ) {
        return (bool)preg_match( $this->getFileNotFoundRegex(), $error );
    }
}