re
/
go
forked from mirror/go
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

add file lock

This commit is contained in:
siddontang 2014-09-04 21:42:27 +08:00
parent 7c4b752908
commit 66c517a7a9
8 changed files with 367 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
filelock/LICENSE Normal file
View File

@ -0,0 +1,27 @@
Copyright (c) 2011 The LevelDB-Go Authors. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
distribution.
* Neither the name of Google Inc. nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

51
filelock/file_lock_darwin_amd64.go Normal file
View File

@ -0,0 +1,51 @@
// Copyright 2012 The LevelDB-Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package filelock
import (
"io"
"os"
"syscall"
"unsafe"
)
// lockCloser hides all of an os.File's methods, except for Close.
type lockCloser struct {
f *os.File
}
func (l lockCloser) Close() error {
return l.f.Close()
}
func Lock(name string) (io.Closer, error) {
f, err := os.Create(name)
if err != nil {
return nil, err
}
// This type matches C's "struct flock" defined in /usr/include/sys/fcntl.h.
// TODO: move this into the standard syscall package.
k := struct {
Start uint64 // sizeof(off_t): 8
Len uint64 // sizeof(off_t): 8
Pid uint32 // sizeof(pid_t): 4
Type uint16 // sizeof(short): 2
Whence uint16 // sizeof(short): 2
}{
Type: syscall.F_WRLCK,
Whence: uint16(os.SEEK_SET),
Start: 0,
Len: 0, // 0 means to lock the entire file.
Pid: uint32(os.Getpid()),
}
_, _, errno := syscall.Syscall(syscall.SYS_FCNTL, f.Fd(), uintptr(syscall.F_SETLK), uintptr(unsafe.Pointer(&k)))
if errno != 0 {
f.Close()
return nil, errno
}
return lockCloser{f}, nil
}

53
filelock/file_lock_freebsd.go Normal file
View File

@ -0,0 +1,53 @@
// Copyright 2014 The LevelDB-Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package filelock
import (
"io"
"os"
"syscall"
"unsafe"
)
// lockCloser hides all of an os.File's methods, except for Close.
type lockCloser struct {
f *os.File
}
func (l lockCloser) Close() error {
return l.f.Close()
}
func Lock(name string) (io.Closer, error) {
f, err := os.Create(name)
if err != nil {
return nil, err
}
// This type matches C's "struct flock" defined in /usr/include/fcntl.h.
// TODO: move this into the standard syscall package.
k := struct {
Start int64 /* off_t starting offset */
Len int64 /* off_t len = 0 means until end of file */
Pid int32 /* pid_t lock owner */
Type int16 /* short lock type: read/write, etc. */
Whence int16 /* short type of l_start */
Sysid int32 /* int remote system id or zero for local */
}{
Start: 0,
Len: 0, // 0 means to lock the entire file.
Pid: int32(os.Getpid()),
Type: syscall.F_WRLCK,
Whence: int16(os.SEEK_SET),
Sysid: 0,
}
_, _, errno := syscall.Syscall(syscall.SYS_FCNTL, f.Fd(), uintptr(syscall.F_SETLK), uintptr(unsafe.Pointer(&k)))
if errno != 0 {
f.Close()
return nil, errno
}
return lockCloser{f}, nil
}

21
filelock/file_lock_generic.go Normal file
View File

@ -0,0 +1,21 @@
// Copyright 2012 The LevelDB-Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build !linux,!amd64
// +build !darwin,!amd64
// +build !openbsd,!amd64
// +build !freebsd
// +build !windows
package filelock
import (
"fmt"
"io"
"runtime"
)
func Lock(name string) (io.Closer, error) {
return nil, fmt.Errorf("leveldb/db: file locking is not implemented on %s/%s", runtime.GOOS, runtime.GOARCH)
}

51
filelock/file_lock_linux_amd64.go Normal file
View File

@ -0,0 +1,51 @@
// Copyright 2012 The LevelDB-Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package filelock
import (
"io"
"os"
"syscall"
"unsafe"
)
// lockCloser hides all of an os.File's methods, except for Close.
type lockCloser struct {
f *os.File
}
func (l lockCloser) Close() error {
return l.f.Close()
}
func Lock(name string) (io.Closer, error) {
f, err := os.Create(name)
if err != nil {
return nil, err
}
// This type matches C's "struct flock" defined in /usr/include/bits/fcntl.h.
// TODO: move this into the standard syscall package.
k := struct {
Type uint32
Whence uint32
Start uint64
Len uint64
Pid uint32
}{
Type: syscall.F_WRLCK,
Whence: uint32(os.SEEK_SET),
Start: 0,
Len: 0, // 0 means to lock the entire file.
Pid: uint32(os.Getpid()),
}
_, _, errno := syscall.Syscall(syscall.SYS_FCNTL, f.Fd(), uintptr(syscall.F_SETLK), uintptr(unsafe.Pointer(&k)))
if errno != 0 {
f.Close()
return nil, errno
}
return lockCloser{f}, nil
}

51
filelock/file_lock_openbsd_amd64.go Normal file
View File

@ -0,0 +1,51 @@
// Copyright 2013 The LevelDB-Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package filelock
import (
"io"
"os"
"syscall"
"unsafe"
)
// lockCloser hides all of an os.File's methods, except for Close.
type lockCloser struct {
f *os.File
}
func (l lockCloser) Close() error {
return l.f.Close()
}
func Lock(name string) (io.Closer, error) {
f, err := os.Create(name)
if err != nil {
return nil, err
}
// This type matches C's "struct flock" defined in /usr/include/fcntl.h.
// TODO: move this into the standard syscall package.
k := struct {
Start uint64
Len uint64
Pid uint32
Type uint32
Whence uint32
}{
Type: syscall.F_WRLCK,
Whence: uint32(os.SEEK_SET),
Start: 0,
Len: 0, // 0 means to lock the entire file.
Pid: uint32(os.Getpid()),
}
_, _, errno := syscall.Syscall(syscall.SYS_FCNTL, f.Fd(), uintptr(syscall.F_SETLK), uintptr(unsafe.Pointer(&k)))
if errno != 0 {
f.Close()
return nil, errno
}
return lockCloser{f}, nil
}

77
filelock/file_lock_test.go Normal file
View File

@ -0,0 +1,77 @@
// Copyright 2014 The LevelDB-Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package filelock
import (
"bytes"
"flag"
"io/ioutil"
"os"
"os/exec"
"testing"
)
var lockFilename = flag.String("lockfile", "", "File to lock. Non-empty value pimples child process.")
func spawn(prog, filename string) ([]byte, error) {
return exec.Command(prog, "-lockfile", filename, "-test.v",
"-test.run=TestLock$").CombinedOutput()
}
// TestLock locks a file, spawns a second process that attempts to grab the
// lock to verify it fails.
// Then it closes the lock, and spawns a third copy to verify it can be
// relocked.
func TestLock(t *testing.T) {
child := *lockFilename != ""
var filename string
if child {
filename = *lockFilename
} else {
f, err := ioutil.TempFile("", "")
if err != nil {
t.Fatal(err)
}
filename = f.Name()
defer os.Remove(filename)
}
// Avoid truncating an existing, non-empty file.
fi, err := os.Stat(filename)
if err == nil && fi.Size() != 0 {
t.Fatal("The file %s is not empty", filename)
}
t.Logf("Locking %s\n", filename)
lock, err := Lock(filename)
if err != nil {
t.Fatalf("Could not lock %s: %v", filename, err)
}
if !child {
t.Logf("Spawning child, should fail to grab lock.")
out, err := spawn(os.Args[0], filename)
if err == nil {
t.Fatalf("Attempt to grab open lock should have failed.\n%s", out)
}
if !bytes.Contains(out, []byte("Could not lock")) {
t.Fatalf("Child failed with unexpected output: %s\n", out)
}
t.Logf("Child failed to grab lock as expected.")
}
t.Logf("Unlocking %s", filename)
if err := lock.Close(); err != nil {
t.Fatalf("Could not unlock %s: %v", filename, err)
}
if !child {
t.Logf("Spawning child, should successfully grab lock.")
if out, err := spawn(os.Args[0], filename); err != nil {
t.Fatalf("Attempt to re-open lock should have succeeded: %v\n%s",
err, out)
}
t.Logf("Child grabbed lock.")
}
}

36
filelock/file_lock_windows.go Normal file
View File

@ -0,0 +1,36 @@
// Copyright 2013 The LevelDB-Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package filelock
import (
"io"
"syscall"
)
// lockCloser hides all of an syscall.Handle's methods, except for Close.
type lockCloser struct {
fd syscall.Handle
}
func (l lockCloser) Close() error {
return syscall.Close(l.fd)
}
func Lock(name string) (io.Closer, error) {
p, err := syscall.UTF16PtrFromString(name)
if err != nil {
return nil, err
}
fd, err := syscall.CreateFile(p,
syscall.GENERIC_READ|syscall.GENERIC_WRITE,
0, nil, syscall.CREATE_ALWAYS,
syscall.FILE_ATTRIBUTE_NORMAL,
0,
)
if err != nil {
return nil, err
}
return lockCloser{fd: fd}, nil
}