93 lines
2.7 KiB
Go
93 lines
2.7 KiB
Go
// Copyright (C) 2014 The Syncthing Authors.
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this file,
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// You can obtain one at https://mozilla.org/MPL/2.0/.
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package model
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import (
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"context"
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"errors"
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"fmt"
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"path/filepath"
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"time"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/syncthing/syncthing/lib/fs"
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)
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// inWritableDir calls fn(path), while making sure that the directory
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// containing `path` is writable for the duration of the call.
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func inWritableDir(fn func(string) error, targetFs fs.Filesystem, path string, ignorePerms bool) error {
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dir := filepath.Dir(path)
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info, err := targetFs.Stat(dir)
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if err != nil {
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return err
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}
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if !info.IsDir() {
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return errors.New("Not a directory: " + path)
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}
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const permBits = fs.ModePerm | fs.ModeSetuid | fs.ModeSetgid | fs.ModeSticky
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var parentErr error
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if mode := info.Mode() & permBits; mode&0o200 == 0 {
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// A non-writeable directory (for this user; we assume that's the
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// relevant part). Temporarily change the mode so we can delete the
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// file or directory inside it.
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parentErr = targetFs.Chmod(dir, mode|0o700)
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if parentErr != nil {
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l.Debugf("Failed to make parent directory writable: %v", parentErr)
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} else {
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// Chmod succeeded, we should change the permissions back on the way
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// out. If we fail we log the error as we have irrevocably messed up
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// at this point. :( (The operation we were called to wrap has
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// succeeded or failed on its own so returning an error to the
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// caller is inappropriate.)
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defer func() {
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if err := targetFs.Chmod(dir, mode); err != nil && !fs.IsNotExist(err) {
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logFn := l.Warnln
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if ignorePerms {
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logFn = l.Debugln
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}
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logFn("Failed to restore directory permissions after gaining write access:", err)
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}
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}()
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}
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}
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err = fn(path)
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if fs.IsPermission(err) && parentErr != nil {
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err = fmt.Errorf("error after failing to make parent directory writable: %w", err)
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}
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return err
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}
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// addTimeUntilCancelled adds time to the counter for the duration of the
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// Context. We do this piecemeal so that polling the counter during a long
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// operation shows a relevant value, instead of the counter just increasing
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// by a large amount at the end of the operation.
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func addTimeUntilCancelled(ctx context.Context, counter prometheus.Counter) {
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t0 := time.Now()
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defer func() {
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if dur := time.Since(t0).Seconds(); dur > 0 {
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counter.Add(dur)
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}
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}()
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ticker := time.NewTicker(time.Second)
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defer ticker.Stop()
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for {
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select {
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case t := <-ticker.C:
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if dur := t.Sub(t0).Seconds(); dur > 0 {
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counter.Add(dur)
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}
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t0 = t
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case <-ctx.Done():
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return
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}
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}
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}
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