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94 lines
2.8 KiB
94 lines
2.8 KiB
// +build windows |
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/* |
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* Copyright 2017 Dgraph Labs, Inc. and Contributors |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0 |
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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package badger |
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// OpenDir opens a directory in windows with write access for syncing. |
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import ( |
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"fmt" |
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"os" |
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"path/filepath" |
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"syscall" |
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"github.com/pkg/errors" |
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) |
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func openDir(path string) (*os.File, error) { |
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fd, err := openDirWin(path) |
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if err != nil { |
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return nil, err |
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} |
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return os.NewFile(uintptr(fd), path), nil |
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} |
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func openDirWin(path string) (fd syscall.Handle, err error) { |
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if len(path) == 0 { |
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return syscall.InvalidHandle, syscall.ERROR_FILE_NOT_FOUND |
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} |
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pathp, err := syscall.UTF16PtrFromString(path) |
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if err != nil { |
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return syscall.InvalidHandle, err |
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} |
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access := uint32(syscall.GENERIC_READ | syscall.GENERIC_WRITE) |
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sharemode := uint32(syscall.FILE_SHARE_READ | syscall.FILE_SHARE_WRITE) |
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createmode := uint32(syscall.OPEN_EXISTING) |
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fl := uint32(syscall.FILE_FLAG_BACKUP_SEMANTICS) |
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return syscall.CreateFile(pathp, access, sharemode, nil, createmode, fl, 0) |
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} |
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// DirectoryLockGuard holds a lock on the directory. |
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type directoryLockGuard struct { |
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path string |
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} |
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// AcquireDirectoryLock acquires exclusive access to a directory. |
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func acquireDirectoryLock(dirPath string, pidFileName string, readOnly bool) (*directoryLockGuard, error) { |
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if readOnly { |
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return nil, ErrWindowsNotSupported |
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} |
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// Convert to absolute path so that Release still works even if we do an unbalanced |
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// chdir in the meantime. |
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absLockFilePath, err := filepath.Abs(filepath.Join(dirPath, pidFileName)) |
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if err != nil { |
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return nil, errors.Wrap(err, "Cannot get absolute path for pid lock file") |
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} |
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f, err := os.OpenFile(absLockFilePath, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0666) |
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if err != nil { |
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return nil, errors.Wrapf(err, |
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"Cannot create pid lock file %q. Another process is using this Badger database", |
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absLockFilePath) |
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} |
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_, err = fmt.Fprintf(f, "%d\n", os.Getpid()) |
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closeErr := f.Close() |
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if err != nil { |
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return nil, errors.Wrap(err, "Cannot write to pid lock file") |
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} |
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if closeErr != nil { |
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return nil, errors.Wrap(closeErr, "Cannot close pid lock file") |
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} |
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return &directoryLockGuard{path: absLockFilePath}, nil |
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} |
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// Release removes the directory lock. |
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func (g *directoryLockGuard) release() error { |
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path := g.path |
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g.path = "" |
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return os.Remove(path) |
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}
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