126 lines
3.4 KiB
Go
126 lines
3.4 KiB
Go
// Copyright (C) 2014 The Syncthing Authors.
|
|
//
|
|
// This program is free software: you can redistribute it and/or modify it
|
|
// under the terms of the GNU General Public License as published by the Free
|
|
// Software Foundation, either version 3 of the License, or (at your option)
|
|
// any later version.
|
|
//
|
|
// This program is distributed in the hope that it will be useful, but WITHOUT
|
|
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
|
|
// more details.
|
|
//
|
|
// You should have received a copy of the GNU General Public License along
|
|
// with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
// Package osutil implements utilities for native OS support.
|
|
package osutil
|
|
|
|
import (
|
|
"errors"
|
|
"fmt"
|
|
"os"
|
|
"path/filepath"
|
|
"runtime"
|
|
"strings"
|
|
"sync"
|
|
)
|
|
|
|
var ErrNoHome = errors.New("No home directory found - set $HOME (or the platform equivalent).")
|
|
|
|
// Try to keep this entire operation atomic-like. We shouldn't be doing this
|
|
// often enough that there is any contention on this lock.
|
|
var renameLock sync.Mutex
|
|
|
|
// Rename renames a file, while trying hard to succeed on various systems by
|
|
// temporarily tweaking directory permissions and removing the destination
|
|
// file when necessary. Will make sure to delete the from file if the
|
|
// operation fails, so use only for situations like committing a temp file to
|
|
// it's final location.
|
|
func Rename(from, to string) error {
|
|
renameLock.Lock()
|
|
defer renameLock.Unlock()
|
|
|
|
// Make sure the destination directory is writeable
|
|
toDir := filepath.Dir(to)
|
|
if info, err := os.Stat(toDir); err == nil {
|
|
os.Chmod(toDir, 0777)
|
|
defer os.Chmod(toDir, info.Mode())
|
|
}
|
|
|
|
// On Windows, make sure the destination file is writeable (or we can't delete it)
|
|
if runtime.GOOS == "windows" {
|
|
os.Chmod(to, 0666)
|
|
err := os.Remove(to)
|
|
if err != nil && !os.IsNotExist(err) {
|
|
return err
|
|
}
|
|
}
|
|
|
|
// Don't leave a dangling temp file in case of rename error
|
|
defer os.Remove(from)
|
|
return os.Rename(from, to)
|
|
}
|
|
|
|
// InWritableDir calls fn(path), while making sure that the directory
|
|
// containing `path` is writable for the duration of the call.
|
|
func InWritableDir(fn func(string) error, path string) error {
|
|
dir := filepath.Dir(path)
|
|
if info, err := os.Stat(dir); err == nil && info.IsDir() && info.Mode()&0200 == 0 {
|
|
// A non-writeable directory (for this user; we assume that's the
|
|
// relevant part). Temporarily change the mode so we can delete the
|
|
// file or directory inside it.
|
|
err = os.Chmod(dir, 0755)
|
|
if err == nil {
|
|
defer func() {
|
|
err = os.Chmod(dir, info.Mode())
|
|
if err != nil {
|
|
// We managed to change the permission bits like a
|
|
// millisecond ago, so it'd be bizarre if we couldn't
|
|
// change it back.
|
|
panic(err)
|
|
}
|
|
}()
|
|
}
|
|
}
|
|
|
|
return fn(path)
|
|
}
|
|
|
|
func ExpandTilde(path string) (string, error) {
|
|
if path == "~" {
|
|
return getHomeDir()
|
|
}
|
|
|
|
path = filepath.FromSlash(path)
|
|
if !strings.HasPrefix(path, fmt.Sprintf("~%c", os.PathSeparator)) {
|
|
return path, nil
|
|
}
|
|
|
|
home, err := getHomeDir()
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
return filepath.Join(home, path[2:]), nil
|
|
}
|
|
|
|
func getHomeDir() (string, error) {
|
|
var home string
|
|
|
|
switch runtime.GOOS {
|
|
case "windows":
|
|
home = filepath.Join(os.Getenv("HomeDrive"), os.Getenv("HomePath"))
|
|
if home == "" {
|
|
home = os.Getenv("UserProfile")
|
|
}
|
|
default:
|
|
home = os.Getenv("HOME")
|
|
}
|
|
|
|
if home == "" {
|
|
return "", ErrNoHome
|
|
}
|
|
|
|
return home, nil
|
|
}
|