Initial QSfera import
This commit is contained in:
Курнат Андрей
+24
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|
||||
version: "2"
|
||||
linters:
|
||||
disable:
|
||||
- errcheck
|
||||
exclusions:
|
||||
generated: lax
|
||||
presets:
|
||||
- comments
|
||||
- common-false-positives
|
||||
- legacy
|
||||
- std-error-handling
|
||||
paths:
|
||||
- third_party$
|
||||
- builtin$
|
||||
- examples$
|
||||
formatters:
|
||||
enable:
|
||||
- gofmt
|
||||
exclusions:
|
||||
generated: lax
|
||||
paths:
|
||||
- third_party$
|
||||
- builtin$
|
||||
- examples$
|
||||
+28
@@ -0,0 +1,28 @@
|
||||
# How to Contribute
|
||||
|
||||
We'd love to accept your patches and contributions to this project. There are
|
||||
just a few small guidelines you need to follow.
|
||||
|
||||
## Contributor License Agreement
|
||||
|
||||
Contributions to this project must be accompanied by a Contributor License
|
||||
Agreement. You (or your employer) retain the copyright to your contribution;
|
||||
this simply gives us permission to use and redistribute your contributions as
|
||||
part of the project. Head over to <https://cla.developers.google.com/> to see
|
||||
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|
||||
|
||||
You generally only need to submit a CLA once, so if you've already submitted one
|
||||
(even if it was for a different project), you probably don't need to do it
|
||||
again.
|
||||
|
||||
## Code reviews
|
||||
|
||||
All submissions, including submissions by project members, require review. We
|
||||
use GitHub pull requests for this purpose. Consult
|
||||
[GitHub Help](https://help.github.com/articles/about-pull-requests/) for more
|
||||
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|
||||
|
||||
## Community Guidelines
|
||||
|
||||
This project follows [Google's Open Source Community
|
||||
Guidelines](https://opensource.google.com/conduct/).
|
||||
+202
@@ -0,0 +1,202 @@
|
||||
|
||||
Apache License
|
||||
Version 2.0, January 2004
|
||||
http://www.apache.org/licenses/
|
||||
|
||||
TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
|
||||
|
||||
1. Definitions.
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Notwithstanding the above, nothing herein shall supersede or modify
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APPENDIX: How to apply the Apache License to your work.
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To apply the Apache License to your work, attach the following
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See the License for the specific language governing permissions and
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|
||||
+74
@@ -0,0 +1,74 @@
|
||||
[](https://github.com/google/renameio/actions?query=workflow%3ATest)
|
||||
[](https://pkg.go.dev/github.com/google/renameio/v2)
|
||||
[](https://goreportcard.com/report/github.com/google/renameio/v2)
|
||||
|
||||
The `renameio` Go package provides a way to atomically create or replace a file or
|
||||
symbolic link.
|
||||
|
||||
## Atomicity vs durability
|
||||
|
||||
`renameio` concerns itself *only* with atomicity, i.e. making sure applications
|
||||
never see unexpected file content (a half-written file, or a 0-byte file).
|
||||
|
||||
As a practical example, consider https://manpages.debian.org/: if there is a
|
||||
power outage while the site is updating, we are okay with losing the manpages
|
||||
which were being rendered at the time of the power outage. They will be added in
|
||||
a later run of the software. We are not okay with having a manpage replaced by a
|
||||
0-byte file under any circumstances, though.
|
||||
|
||||
## Advantages of this package
|
||||
|
||||
There are other packages for atomically replacing files, and sometimes ad-hoc
|
||||
implementations can be found in programs.
|
||||
|
||||
A naive approach to the problem is to create a temporary file followed by a call
|
||||
to `os.Rename()`. However, there are a number of subtleties which make the
|
||||
correct sequence of operations hard to identify:
|
||||
|
||||
* The temporary file should be removed when an error occurs, but a remove must
|
||||
not be attempted if the rename succeeded, as a new file might have been
|
||||
created with the same name. This renders a throwaway `defer
|
||||
os.Remove(t.Name())` insufficient; state must be kept.
|
||||
|
||||
* The temporary file must be created on the same file system (same mount point)
|
||||
for the rename to work, but the TMPDIR environment variable should still be
|
||||
respected, e.g. to direct temporary files into a separate directory outside of
|
||||
the webserver’s document root but on the same file system.
|
||||
|
||||
* On POSIX operating systems, the
|
||||
[`fsync`](https://manpages.debian.org/stretch/manpages-dev/fsync.2) system
|
||||
call must be used to ensure that the `os.Rename()` call will not result in a
|
||||
0-length file.
|
||||
|
||||
This package attempts to get all of these details right, provides an intuitive,
|
||||
yet flexible API and caters to use-cases where high performance is required.
|
||||
|
||||
## Major changes in v2
|
||||
|
||||
With major version renameio/v2, `renameio.WriteFile` changes the way that
|
||||
permissions are handled. Before version 2, files were created with the
|
||||
permissions passed to the function, ignoring the
|
||||
[umask](https://en.wikipedia.org/wiki/Umask). From version 2 onwards, these
|
||||
permissions are further modified by process' umask (usually the user's
|
||||
preferred umask).
|
||||
|
||||
If you were relying on the umask being ignored, add the
|
||||
`renameio.IgnoreUmask()` option to your `renameio.WriteFile` calls when
|
||||
upgrading to v2.
|
||||
|
||||
## Windows support
|
||||
|
||||
It is [not possible to reliably write files atomically on
|
||||
Windows](https://github.com/golang/go/issues/22397#issuecomment-498856679), and
|
||||
[`chmod` is not reliably supported by the Go standard library on
|
||||
Windows](https://github.com/google/renameio/issues/17).
|
||||
|
||||
As it is not possible to provide a correct implementation, this package does not
|
||||
export any functions on Windows.
|
||||
|
||||
## Disclaimer
|
||||
|
||||
This is not an official Google product (experimental or otherwise), it
|
||||
is just code that happens to be owned by Google.
|
||||
|
||||
This project is not affiliated with the Go project.
|
||||
+21
@@ -0,0 +1,21 @@
|
||||
// Copyright 2018 Google Inc.
|
||||
//
|
||||
// Licensed under the Apache License, Version 2.0 (the "License");
|
||||
// you may not use this file except in compliance with the License.
|
||||
// You may obtain a copy of the License at
|
||||
//
|
||||
// http://www.apache.org/licenses/LICENSE-2.0
|
||||
//
|
||||
// Unless required by applicable law or agreed to in writing, software
|
||||
// distributed under the License is distributed on an "AS IS" BASIS,
|
||||
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||||
// See the License for the specific language governing permissions and
|
||||
// limitations under the License.
|
||||
|
||||
// Package renameio provides a way to atomically create or replace a file or
|
||||
// symbolic link.
|
||||
//
|
||||
// Caveat: this package requires the file system rename(2) implementation to be
|
||||
// atomic. Notably, this is not the case when using NFS with multiple clients:
|
||||
// https://stackoverflow.com/a/41396801
|
||||
package renameio
|
||||
+98
@@ -0,0 +1,98 @@
|
||||
// Copyright 2021 Google Inc.
|
||||
//
|
||||
// Licensed under the Apache License, Version 2.0 (the "License");
|
||||
// you may not use this file except in compliance with the License.
|
||||
// You may obtain a copy of the License at
|
||||
//
|
||||
// http://www.apache.org/licenses/LICENSE-2.0
|
||||
//
|
||||
// Unless required by applicable law or agreed to in writing, software
|
||||
// distributed under the License is distributed on an "AS IS" BASIS,
|
||||
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||||
// See the License for the specific language governing permissions and
|
||||
// limitations under the License.
|
||||
|
||||
//go:build !windows
|
||||
|
||||
package renameio
|
||||
|
||||
import "os"
|
||||
|
||||
// Option is the interface implemented by all configuration function return
|
||||
// values.
|
||||
type Option interface {
|
||||
apply(*config)
|
||||
}
|
||||
|
||||
type optionFunc func(*config)
|
||||
|
||||
func (fn optionFunc) apply(cfg *config) {
|
||||
fn(cfg)
|
||||
}
|
||||
|
||||
// WithTempDir configures the directory to use for temporary, uncommitted
|
||||
// files. Suitable for using a cached directory from
|
||||
// TempDir(filepath.Base(path)).
|
||||
func WithTempDir(dir string) Option {
|
||||
return optionFunc(func(cfg *config) {
|
||||
cfg.dir = dir
|
||||
})
|
||||
}
|
||||
|
||||
// WithPermissions sets the permissions for the target file while respecting
|
||||
// the umask(2). Bits set in the umask are removed from the permissions given
|
||||
// unless IgnoreUmask is used.
|
||||
func WithPermissions(perm os.FileMode) Option {
|
||||
perm &= os.ModePerm
|
||||
return optionFunc(func(cfg *config) {
|
||||
cfg.createPerm = perm
|
||||
})
|
||||
}
|
||||
|
||||
// IgnoreUmask causes the permissions configured using WithPermissions to be
|
||||
// applied directly without applying the umask.
|
||||
func IgnoreUmask() Option {
|
||||
return optionFunc(func(cfg *config) {
|
||||
cfg.ignoreUmask = true
|
||||
})
|
||||
}
|
||||
|
||||
// WithStaticPermissions sets the permissions for the target file ignoring the
|
||||
// umask(2). This is equivalent to calling Chmod() on the file handle or using
|
||||
// WithPermissions in combination with IgnoreUmask.
|
||||
func WithStaticPermissions(perm os.FileMode) Option {
|
||||
perm &= os.ModePerm
|
||||
return optionFunc(func(cfg *config) {
|
||||
cfg.chmod = &perm
|
||||
})
|
||||
}
|
||||
|
||||
// WithExistingPermissions configures the file creation to try to use the
|
||||
// permissions from an already existing target file. If the target file doesn't
|
||||
// exist yet or is not a regular file the default permissions are used unless
|
||||
// overridden using WithPermissions or WithStaticPermissions.
|
||||
func WithExistingPermissions() Option {
|
||||
return optionFunc(func(c *config) {
|
||||
c.attemptPermCopy = true
|
||||
})
|
||||
}
|
||||
|
||||
// WithReplaceOnClose causes PendingFile.Close() to actually call
|
||||
// CloseAtomicallyReplace(). This means PendingFile implements io.Closer while
|
||||
// maintaining atomicity per default.
|
||||
func WithReplaceOnClose() Option {
|
||||
return optionFunc(func(c *config) {
|
||||
c.renameOnClose = true
|
||||
})
|
||||
}
|
||||
|
||||
// WithRoot specifies a root directory to use when working with files.
|
||||
// See [os.Root] and https://go.dev/blog/osroot for more details.
|
||||
//
|
||||
// When WithRoot is used, WithTempDir (and the $TMPDIR environment variable) are
|
||||
// ignored, as temporary files must be created in the specified root directory.
|
||||
func WithRoot(root *os.Root) Option {
|
||||
return optionFunc(func(c *config) {
|
||||
c.root = root
|
||||
})
|
||||
}
|
||||
+392
@@ -0,0 +1,392 @@
|
||||
// Copyright 2018 Google Inc.
|
||||
//
|
||||
// Licensed under the Apache License, Version 2.0 (the "License");
|
||||
// you may not use this file except in compliance with the License.
|
||||
// You may obtain a copy of the License at
|
||||
//
|
||||
// http://www.apache.org/licenses/LICENSE-2.0
|
||||
//
|
||||
// Unless required by applicable law or agreed to in writing, software
|
||||
// distributed under the License is distributed on an "AS IS" BASIS,
|
||||
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||||
// See the License for the specific language governing permissions and
|
||||
// limitations under the License.
|
||||
|
||||
//go:build !windows
|
||||
|
||||
package renameio
|
||||
|
||||
import (
|
||||
"math/rand/v2"
|
||||
"os"
|
||||
"path/filepath"
|
||||
"strconv"
|
||||
)
|
||||
|
||||
// Default permissions for created files
|
||||
const defaultPerm os.FileMode = 0o600
|
||||
|
||||
// nextrandom is a function generating a random number.
|
||||
var nextrandom = rand.Int64
|
||||
|
||||
// openTempFile creates a randomly named file and returns an open handle. It is
|
||||
// similar to os.CreateTemp except that the directory must be given, the file
|
||||
// permissions can be controlled and patterns in the name are not supported.
|
||||
// The name is always suffixed with a random number.
|
||||
func openTempFile(dir, name string, perm os.FileMode) (*os.File, error) {
|
||||
prefix := filepath.Join(dir, name)
|
||||
|
||||
for attempt := 0; ; {
|
||||
// Generate a reasonably random name which is unlikely to already
|
||||
// exist. O_EXCL ensures that existing files generate an error.
|
||||
name := prefix + strconv.FormatInt(nextrandom(), 10)
|
||||
|
||||
f, err := os.OpenFile(name, os.O_RDWR|os.O_CREATE|os.O_EXCL, perm)
|
||||
if !os.IsExist(err) {
|
||||
return f, err
|
||||
}
|
||||
|
||||
if attempt++; attempt > 10000 {
|
||||
return nil, &os.PathError{
|
||||
Op: "tempfile",
|
||||
Path: name,
|
||||
Err: os.ErrExist,
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// openTempFileRoot creates a randomly named file in root and returns an open
|
||||
// handle. It is similar to os.CreateTemp except that the directory must be
|
||||
// given, the file permissions can be controlled and patterns in the name are
|
||||
// not supported. The name is always suffixed with a random number.
|
||||
func openTempFileRoot(root *os.Root, name string, perm os.FileMode) (string, *os.File, error) {
|
||||
prefix := name
|
||||
|
||||
for attempt := 0; ; {
|
||||
// Generate a reasonably random name which is unlikely to already
|
||||
// exist. O_EXCL ensures that existing files generate an error.
|
||||
name := prefix + strconv.FormatInt(nextrandom(), 10)
|
||||
|
||||
f, err := root.OpenFile(name, os.O_RDWR|os.O_CREATE|os.O_EXCL, perm)
|
||||
if !os.IsExist(err) {
|
||||
return name, f, err
|
||||
}
|
||||
|
||||
if attempt++; attempt > 10000 {
|
||||
return "", nil, &os.PathError{
|
||||
Op: "tempfile",
|
||||
Path: name,
|
||||
Err: os.ErrExist,
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// TempDir checks whether os.TempDir() can be used as a temporary directory for
|
||||
// later atomically replacing files within dest. If no (os.TempDir() resides on
|
||||
// a different mount point), dest is returned.
|
||||
//
|
||||
// Note that the returned value ceases to be valid once either os.TempDir()
|
||||
// changes (e.g. on Linux, once the TMPDIR environment variable changes) or the
|
||||
// file system is unmounted.
|
||||
func TempDir(dest string) string {
|
||||
return tempDir("", filepath.Join(dest, "renameio-TempDir"))
|
||||
}
|
||||
|
||||
func tempDir(dir, dest string) string {
|
||||
if dir != "" {
|
||||
return dir // caller-specified directory always wins
|
||||
}
|
||||
|
||||
// Chose the destination directory as temporary directory so that we
|
||||
// definitely can rename the file, for which both temporary and destination
|
||||
// file need to point to the same mount point.
|
||||
fallback := filepath.Dir(dest)
|
||||
|
||||
// The user might have overridden the os.TempDir() return value by setting
|
||||
// the TMPDIR environment variable.
|
||||
tmpdir := os.TempDir()
|
||||
|
||||
testsrc, err := os.CreateTemp(tmpdir, "."+filepath.Base(dest))
|
||||
if err != nil {
|
||||
return fallback
|
||||
}
|
||||
cleanup := true
|
||||
defer func() {
|
||||
if cleanup {
|
||||
os.Remove(testsrc.Name())
|
||||
}
|
||||
}()
|
||||
testsrc.Close()
|
||||
|
||||
testdest, err := os.CreateTemp(filepath.Dir(dest), "."+filepath.Base(dest))
|
||||
if err != nil {
|
||||
return fallback
|
||||
}
|
||||
defer os.Remove(testdest.Name())
|
||||
testdest.Close()
|
||||
|
||||
if err := os.Rename(testsrc.Name(), testdest.Name()); err != nil {
|
||||
return fallback
|
||||
}
|
||||
cleanup = false // testsrc no longer exists
|
||||
return tmpdir
|
||||
}
|
||||
|
||||
// PendingFile is a pending temporary file, waiting to replace the destination
|
||||
// path in a call to CloseAtomicallyReplace.
|
||||
type PendingFile struct {
|
||||
*os.File
|
||||
|
||||
path string
|
||||
done bool
|
||||
closed bool
|
||||
replaceOnClose bool
|
||||
root *os.Root
|
||||
tmpname string
|
||||
}
|
||||
|
||||
// Cleanup is a no-op if CloseAtomicallyReplace succeeded, and otherwise closes
|
||||
// and removes the temporary file.
|
||||
//
|
||||
// This method is not safe for concurrent use by multiple goroutines.
|
||||
func (t *PendingFile) Cleanup() error {
|
||||
if t.done {
|
||||
return nil
|
||||
}
|
||||
// An error occurred. Close and remove the tempfile. Errors are returned for
|
||||
// reporting, there is nothing the caller can recover here.
|
||||
var closeErr error
|
||||
if !t.closed {
|
||||
closeErr = t.File.Close()
|
||||
}
|
||||
if t.root != nil {
|
||||
if err := t.root.Remove(t.tmpname); err != nil {
|
||||
return err
|
||||
}
|
||||
} else {
|
||||
if err := os.Remove(t.Name()); err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
t.done = true
|
||||
return closeErr
|
||||
}
|
||||
|
||||
// CloseAtomicallyReplace closes the temporary file and atomically replaces
|
||||
// the destination file with it, i.e., a concurrent open(2) call will either
|
||||
// open the file previously located at the destination path (if any), or the
|
||||
// just written file, but the file will always be present.
|
||||
//
|
||||
// This method is not safe for concurrent use by multiple goroutines.
|
||||
func (t *PendingFile) CloseAtomicallyReplace() error {
|
||||
// Even on an ordered file system (e.g. ext4 with data=ordered) or file
|
||||
// systems with write barriers, we cannot skip the fsync(2) call as per
|
||||
// Theodore Ts'o (ext2/3/4 lead developer):
|
||||
//
|
||||
// > data=ordered only guarantees the avoidance of stale data (e.g., the previous
|
||||
// > contents of a data block showing up after a crash, where the previous data
|
||||
// > could be someone's love letters, medical records, etc.). Without the fsync(2)
|
||||
// > a zero-length file is a valid and possible outcome after the rename.
|
||||
if err := t.Sync(); err != nil {
|
||||
return err
|
||||
}
|
||||
t.closed = true
|
||||
if err := t.File.Close(); err != nil {
|
||||
return err
|
||||
}
|
||||
if t.root != nil {
|
||||
if err := t.root.Rename(t.tmpname, t.path); err != nil {
|
||||
return err
|
||||
}
|
||||
} else {
|
||||
if err := os.Rename(t.Name(), t.path); err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
t.done = true
|
||||
return nil
|
||||
}
|
||||
|
||||
// Close closes the file. By default it just calls Close() on the underlying file. For PendingFiles created with
|
||||
// WithReplaceOnClose it calls CloseAtomicallyReplace() instead.
|
||||
func (t *PendingFile) Close() error {
|
||||
if t.replaceOnClose {
|
||||
return t.CloseAtomicallyReplace()
|
||||
}
|
||||
return t.File.Close()
|
||||
}
|
||||
|
||||
// TempFile creates a temporary file destined to atomically creating or
|
||||
// replacing the destination file at path.
|
||||
//
|
||||
// If dir is the empty string, TempDir(filepath.Base(path)) is used. If you are
|
||||
// going to write a large number of files to the same file system, store the
|
||||
// result of TempDir(filepath.Base(path)) and pass it instead of the empty
|
||||
// string.
|
||||
//
|
||||
// The file's permissions will be 0600. You can change these by explicitly
|
||||
// calling Chmod on the returned PendingFile.
|
||||
func TempFile(dir, path string) (*PendingFile, error) {
|
||||
return NewPendingFile(path, WithTempDir(dir), WithStaticPermissions(defaultPerm))
|
||||
}
|
||||
|
||||
type config struct {
|
||||
dir, path string
|
||||
createPerm os.FileMode
|
||||
attemptPermCopy bool
|
||||
ignoreUmask bool
|
||||
chmod *os.FileMode
|
||||
renameOnClose bool
|
||||
root *os.Root
|
||||
}
|
||||
|
||||
// NewPendingFile creates a temporary file destined to atomically creating or
|
||||
// replacing the destination file at path.
|
||||
//
|
||||
// TempDir(filepath.Base(path)) is used to store the temporary file. If you are
|
||||
// going to write a large number of files to the same file system, use the
|
||||
// result of TempDir(filepath.Base(path)) with the WithTempDir option.
|
||||
//
|
||||
// The file's permissions will be (0600 & ^umask). Use WithPermissions,
|
||||
// IgnoreUmask, WithStaticPermissions and WithExistingPermissions to control
|
||||
// them.
|
||||
func NewPendingFile(path string, opts ...Option) (*PendingFile, error) {
|
||||
cfg := config{
|
||||
path: path,
|
||||
createPerm: defaultPerm,
|
||||
}
|
||||
|
||||
for _, o := range opts {
|
||||
o.apply(&cfg)
|
||||
}
|
||||
|
||||
if cfg.ignoreUmask && cfg.chmod == nil {
|
||||
cfg.chmod = &cfg.createPerm
|
||||
}
|
||||
|
||||
if cfg.attemptPermCopy {
|
||||
var existing os.FileInfo
|
||||
var err error
|
||||
if cfg.root != nil {
|
||||
existing, err = cfg.root.Lstat(cfg.path)
|
||||
} else {
|
||||
existing, err = os.Lstat(cfg.path)
|
||||
}
|
||||
// Try to determine permissions from an existing file.
|
||||
if err == nil && existing.Mode().IsRegular() {
|
||||
perm := existing.Mode() & os.ModePerm
|
||||
cfg.chmod = &perm
|
||||
|
||||
// Try to already create file with desired permissions; at worst
|
||||
// a chmod will be needed afterwards.
|
||||
cfg.createPerm = perm
|
||||
} else if err != nil && !os.IsNotExist(err) {
|
||||
return nil, err
|
||||
}
|
||||
}
|
||||
|
||||
var f *os.File
|
||||
var err error
|
||||
var tmpname string
|
||||
if cfg.root != nil {
|
||||
tmpname, f, err = openTempFileRoot(cfg.root, "."+filepath.Base(cfg.path), cfg.createPerm)
|
||||
} else {
|
||||
f, err = openTempFile(tempDir(cfg.dir, cfg.path), "."+filepath.Base(cfg.path), cfg.createPerm)
|
||||
}
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
if cfg.chmod != nil {
|
||||
if fi, err := f.Stat(); err != nil {
|
||||
return nil, err
|
||||
} else if fi.Mode()&os.ModePerm != *cfg.chmod {
|
||||
if err := f.Chmod(*cfg.chmod); err != nil {
|
||||
return nil, err
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
return &PendingFile{
|
||||
File: f,
|
||||
path: cfg.path,
|
||||
replaceOnClose: cfg.renameOnClose,
|
||||
root: cfg.root,
|
||||
tmpname: tmpname,
|
||||
}, nil
|
||||
}
|
||||
|
||||
// Symlink wraps os.Symlink, replacing an existing symlink with the same name
|
||||
// atomically (os.Symlink fails when newname already exists, at least on Linux).
|
||||
func Symlink(oldname, newname string) error {
|
||||
// Fast path: if newname does not exist yet, we can skip the whole dance
|
||||
// below.
|
||||
if err := os.Symlink(oldname, newname); err == nil || !os.IsExist(err) {
|
||||
return err
|
||||
}
|
||||
|
||||
// We need to use os.MkdirTemp, as we cannot overwrite a os.CreateTemp file,
|
||||
// and removing+symlinking creates a TOCTOU race.
|
||||
d, err := os.MkdirTemp(filepath.Dir(newname), "."+filepath.Base(newname))
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
cleanup := true
|
||||
defer func() {
|
||||
if cleanup {
|
||||
os.RemoveAll(d)
|
||||
}
|
||||
}()
|
||||
|
||||
symlink := filepath.Join(d, "tmp.symlink")
|
||||
if err := os.Symlink(oldname, symlink); err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
if err := os.Rename(symlink, newname); err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
cleanup = false
|
||||
return os.RemoveAll(d)
|
||||
}
|
||||
|
||||
// SymlinkRoot wraps os.Symlink, replacing an existing symlink with the same
|
||||
// name atomically (os.Symlink fails when newname already exists, at least on
|
||||
// Linux).
|
||||
func SymlinkRoot(root *os.Root, oldname, newname string) error {
|
||||
// Fast path: if newname does not exist yet, we can skip the whole dance
|
||||
// below.
|
||||
if err := root.Symlink(oldname, newname); err == nil || !os.IsExist(err) {
|
||||
return err
|
||||
}
|
||||
|
||||
// We need to use os.MkdirTemp, as we cannot overwrite a os.CreateTemp file,
|
||||
// and removing+symlinking creates a TOCTOU race.
|
||||
//
|
||||
// There is no os.Root-compatible os.MkdirTemp, so we use the path directly.
|
||||
d, err := os.MkdirTemp(root.Name(), "."+filepath.Base(newname))
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
cleanup := true
|
||||
defer func() {
|
||||
if cleanup {
|
||||
os.RemoveAll(d)
|
||||
}
|
||||
}()
|
||||
|
||||
symlink := filepath.Join(filepath.Base(d), "tmp.symlink")
|
||||
if err := root.Symlink(oldname, symlink); err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
if err := root.Rename(symlink, newname); err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
cleanup = false
|
||||
return os.RemoveAll(d)
|
||||
}
|
||||
+40
@@ -0,0 +1,40 @@
|
||||
// Copyright 2018 Google Inc.
|
||||
//
|
||||
// Licensed under the Apache License, Version 2.0 (the "License");
|
||||
// you may not use this file except in compliance with the License.
|
||||
// You may obtain a copy of the License at
|
||||
//
|
||||
// http://www.apache.org/licenses/LICENSE-2.0
|
||||
//
|
||||
// Unless required by applicable law or agreed to in writing, software
|
||||
// distributed under the License is distributed on an "AS IS" BASIS,
|
||||
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||||
// See the License for the specific language governing permissions and
|
||||
// limitations under the License.
|
||||
|
||||
//go:build !windows
|
||||
|
||||
package renameio
|
||||
|
||||
import "os"
|
||||
|
||||
// WriteFile mirrors os.WriteFile, replacing an existing file with the same
|
||||
// name atomically.
|
||||
func WriteFile(filename string, data []byte, perm os.FileMode, opts ...Option) error {
|
||||
opts = append([]Option{
|
||||
WithPermissions(perm),
|
||||
WithExistingPermissions(),
|
||||
}, opts...)
|
||||
|
||||
t, err := NewPendingFile(filename, opts...)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
defer t.Cleanup()
|
||||
|
||||
if _, err := t.Write(data); err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
return t.CloseAtomicallyReplace()
|
||||
}
|
||||
Reference in New Issue
Block a user