diff --git a/default.yaml b/default.yaml index cd21e0e1..676f33b4 100644 --- a/default.yaml +++ b/default.yaml @@ -746,6 +746,12 @@ debug: # set to `null`, "", leave blank, or omit to disable # pprof-listener: "localhost:6060" +# lock file preventing multiple instances of Ergo from accidentally being +# started at once. comment out or set to the empty string ("") to disable. +# this path is relative to the working directory; you may want to use an +# absolute path instead: +lock-file: "ircd.lock" + # datastore configuration datastore: # path to the datastore diff --git a/go.mod b/go.mod index 0a4fce8c..678c6699 100644 --- a/go.mod +++ b/go.mod @@ -25,6 +25,8 @@ require ( gopkg.in/yaml.v2 v2.4.0 ) +require github.com/gofrs/flock v0.8.1 + require ( github.com/tidwall/btree v0.6.1 // indirect github.com/tidwall/gjson v1.10.2 // indirect diff --git a/go.sum b/go.sum index 272afd4d..09fe42c1 100644 --- a/go.sum +++ b/go.sum @@ -21,6 +21,8 @@ github.com/go-sql-driver/mysql v1.6.0 h1:BCTh4TKNUYmOmMUcQ3IipzF5prigylS7XXjEkfC github.com/go-sql-driver/mysql v1.6.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg= github.com/go-test/deep v1.0.6 h1:UHSEyLZUwX9Qoi99vVwvewiMC8mM2bf7XEM2nqvzEn8= github.com/go-test/deep v1.0.6/go.mod h1:QV8Hv/iy04NyLBxAdO9njL0iVPN1S4d/A3NVv1V36o8= +github.com/gofrs/flock v0.8.1 h1:+gYjHKf32LDeiEEFhQaotPbLuUXjY5ZqxKgXy7n59aw= +github.com/gofrs/flock v0.8.1/go.mod h1:F1TvTiK9OcQqauNUHlbJvyl9Qa1QvF/gOUDKA14jxHU= github.com/golang-jwt/jwt v3.2.2+incompatible h1:IfV12K8xAKAnZqdXVzCZ+TOjboZ2keLg81eXfW3O+oY= github.com/golang-jwt/jwt v3.2.2+incompatible/go.mod h1:8pz2t5EyA70fFQQSrl6XZXzqecmYZeUEB8OUGHkxJ+I= github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U= diff --git a/irc/config.go b/irc/config.go index 3d753b43..68019179 100644 --- a/irc/config.go +++ b/irc/config.go @@ -616,6 +616,8 @@ type Config struct { languageManager *languages.Manager + LockFile string `yaml:"lock-file"` + Datastore struct { Path string AutoUpgrade bool diff --git a/irc/flock/flock.go b/irc/flock/flock.go new file mode 100644 index 00000000..42d89270 --- /dev/null +++ b/irc/flock/flock.go @@ -0,0 +1,24 @@ +//go:build !plan9 + +package flock + +import ( + "errors" + + "github.com/gofrs/flock" +) + +var ( + CouldntAcquire = errors.New("Couldn't acquire flock (is another Ergo running?)") +) + +func TryAcquireFlock(path string) (fl Flocker, err error) { + f := flock.New(path) + success, err := f.TryLock() + if err != nil { + return nil, err + } else if !success { + return nil, CouldntAcquire + } + return f, nil +} diff --git a/irc/flock/flock_iface.go b/irc/flock/flock_iface.go new file mode 100644 index 00000000..87614571 --- /dev/null +++ b/irc/flock/flock_iface.go @@ -0,0 +1,14 @@ +package flock + +// documentation for github.com/gofrs/flock incorrectly claims that +// Flock implements sync.Locker; it does not because the Unlock method +// has a return type (err). +type Flocker interface { + Unlock() error +} + +type noopFlocker struct{} + +func (n *noopFlocker) Unlock() error { + return nil +} diff --git a/irc/flock/flock_plan9.go b/irc/flock/flock_plan9.go new file mode 100644 index 00000000..06ffeb7c --- /dev/null +++ b/irc/flock/flock_plan9.go @@ -0,0 +1,7 @@ +//go:build plan9 + +package flock + +func TryAcquireFlock(path string) (fl Flocker, err error) { + return &noopFlocker{}, nil +} diff --git a/irc/server.go b/irc/server.go index 542b1e21..270a361c 100644 --- a/irc/server.go +++ b/irc/server.go @@ -25,6 +25,7 @@ import ( "github.com/ergochat/ergo/irc/caps" "github.com/ergochat/ergo/irc/connection_limits" "github.com/ergochat/ergo/irc/flatip" + "github.com/ergochat/ergo/irc/flock" "github.com/ergochat/ergo/irc/history" "github.com/ergochat/ergo/irc/logger" "github.com/ergochat/ergo/irc/modes" @@ -88,6 +89,7 @@ type Server struct { whoWas WhoWasList stats Stats semaphores ServerSemaphores + flock flock.Flocker defcon uint32 } @@ -585,6 +587,19 @@ func (server *Server) applyConfig(config *Config) (err error) { server.logger.Info("server", "Using config file", server.configFilename) + if initial { + if config.LockFile != "" { + server.flock, err = flock.TryAcquireFlock(config.LockFile) + if err != nil { + return fmt.Errorf("failed to acquire flock on %s: %w", + config.LockFile, err) + } + } + // the lock is never released until quit; we need to save a pointer + // to the (*flock.Flock) object so it doesn't get GC'ed, which would + // close the file and surrender the lock + } + // first, reload config sections for functionality implemented in subpackages: wasLoggingRawIO := !initial && server.logger.IsLoggingRawIO() err = server.logger.ApplyConfig(config.Logging) diff --git a/traditional.yaml b/traditional.yaml index ce94944d..ca3bbc88 100644 --- a/traditional.yaml +++ b/traditional.yaml @@ -718,6 +718,12 @@ debug: # set to `null`, "", leave blank, or omit to disable # pprof-listener: "localhost:6060" +# lock file preventing multiple instances of Ergo from accidentally being +# started at once. comment out or set to the empty string ("") to disable. +# this path is relative to the working directory; you may want to use an +# absolute path instead: +lock-file: "ircd.lock" + # datastore configuration datastore: # path to the datastore diff --git a/vendor/github.com/gofrs/flock/.gitignore b/vendor/github.com/gofrs/flock/.gitignore new file mode 100644 index 00000000..daf913b1 --- /dev/null +++ b/vendor/github.com/gofrs/flock/.gitignore @@ -0,0 +1,24 @@ +# Compiled Object files, Static and Dynamic libs (Shared Objects) +*.o +*.a +*.so + +# Folders +_obj +_test + +# Architecture specific extensions/prefixes +*.[568vq] +[568vq].out + +*.cgo1.go +*.cgo2.c +_cgo_defun.c +_cgo_gotypes.go +_cgo_export.* + +_testmain.go + +*.exe +*.test +*.prof diff --git a/vendor/github.com/gofrs/flock/.travis.yml b/vendor/github.com/gofrs/flock/.travis.yml new file mode 100644 index 00000000..b16d040f --- /dev/null +++ b/vendor/github.com/gofrs/flock/.travis.yml @@ -0,0 +1,10 @@ +language: go +go: + - 1.14.x + - 1.15.x +script: go test -v -check.vv -race ./... +sudo: false +notifications: + email: + on_success: never + on_failure: always diff --git a/vendor/github.com/gofrs/flock/LICENSE b/vendor/github.com/gofrs/flock/LICENSE new file mode 100644 index 00000000..8b8ff36f --- /dev/null +++ b/vendor/github.com/gofrs/flock/LICENSE @@ -0,0 +1,27 @@ +Copyright (c) 2015-2020, Tim Heckman +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 gofrs 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 HOLDER 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. diff --git a/vendor/github.com/gofrs/flock/README.md b/vendor/github.com/gofrs/flock/README.md new file mode 100644 index 00000000..71ce6369 --- /dev/null +++ b/vendor/github.com/gofrs/flock/README.md @@ -0,0 +1,41 @@ +# flock +[![TravisCI Build Status](https://img.shields.io/travis/gofrs/flock/master.svg?style=flat)](https://travis-ci.org/gofrs/flock) +[![GoDoc](https://img.shields.io/badge/godoc-flock-blue.svg?style=flat)](https://godoc.org/github.com/gofrs/flock) +[![License](https://img.shields.io/badge/license-BSD_3--Clause-brightgreen.svg?style=flat)](https://github.com/gofrs/flock/blob/master/LICENSE) +[![Go Report Card](https://goreportcard.com/badge/github.com/gofrs/flock)](https://goreportcard.com/report/github.com/gofrs/flock) + +`flock` implements a thread-safe sync.Locker interface for file locking. It also +includes a non-blocking TryLock() function to allow locking without blocking execution. + +## License +`flock` is released under the BSD 3-Clause License. See the `LICENSE` file for more details. + +## Go Compatibility +This package makes use of the `context` package that was introduced in Go 1.7. As such, this +package has an implicit dependency on Go 1.7+. + +## Installation +``` +go get -u github.com/gofrs/flock +``` + +## Usage +```Go +import "github.com/gofrs/flock" + +fileLock := flock.New("/var/lock/go-lock.lock") + +locked, err := fileLock.TryLock() + +if err != nil { + // handle locking error +} + +if locked { + // do work + fileLock.Unlock() +} +``` + +For more detailed usage information take a look at the package API docs on +[GoDoc](https://godoc.org/github.com/gofrs/flock). diff --git a/vendor/github.com/gofrs/flock/appveyor.yml b/vendor/github.com/gofrs/flock/appveyor.yml new file mode 100644 index 00000000..909b4bf7 --- /dev/null +++ b/vendor/github.com/gofrs/flock/appveyor.yml @@ -0,0 +1,25 @@ +version: '{build}' + +build: false +deploy: false + +clone_folder: 'c:\gopath\src\github.com\gofrs\flock' + +environment: + GOPATH: 'c:\gopath' + GOVERSION: '1.15' + +init: + - git config --global core.autocrlf input + +install: + - rmdir c:\go /s /q + - appveyor DownloadFile https://storage.googleapis.com/golang/go%GOVERSION%.windows-amd64.msi + - msiexec /i go%GOVERSION%.windows-amd64.msi /q + - set Path=c:\go\bin;c:\gopath\bin;%Path% + - go version + - go env + +test_script: + - go get -t ./... + - go test -race -v ./... diff --git a/vendor/github.com/gofrs/flock/flock.go b/vendor/github.com/gofrs/flock/flock.go new file mode 100644 index 00000000..95c784ca --- /dev/null +++ b/vendor/github.com/gofrs/flock/flock.go @@ -0,0 +1,144 @@ +// Copyright 2015 Tim Heckman. All rights reserved. +// Use of this source code is governed by the BSD 3-Clause +// license that can be found in the LICENSE file. + +// Package flock implements a thread-safe interface for file locking. +// It also includes a non-blocking TryLock() function to allow locking +// without blocking execution. +// +// Package flock is released under the BSD 3-Clause License. See the LICENSE file +// for more details. +// +// While using this library, remember that the locking behaviors are not +// guaranteed to be the same on each platform. For example, some UNIX-like +// operating systems will transparently convert a shared lock to an exclusive +// lock. If you Unlock() the flock from a location where you believe that you +// have the shared lock, you may accidentally drop the exclusive lock. +package flock + +import ( + "context" + "os" + "runtime" + "sync" + "time" +) + +// Flock is the struct type to handle file locking. All fields are unexported, +// with access to some of the fields provided by getter methods (Path() and Locked()). +type Flock struct { + path string + m sync.RWMutex + fh *os.File + l bool + r bool +} + +// New returns a new instance of *Flock. The only parameter +// it takes is the path to the desired lockfile. +func New(path string) *Flock { + return &Flock{path: path} +} + +// NewFlock returns a new instance of *Flock. The only parameter +// it takes is the path to the desired lockfile. +// +// Deprecated: Use New instead. +func NewFlock(path string) *Flock { + return New(path) +} + +// Close is equivalent to calling Unlock. +// +// This will release the lock and close the underlying file descriptor. +// It will not remove the file from disk, that's up to your application. +func (f *Flock) Close() error { + return f.Unlock() +} + +// Path returns the path as provided in NewFlock(). +func (f *Flock) Path() string { + return f.path +} + +// Locked returns the lock state (locked: true, unlocked: false). +// +// Warning: by the time you use the returned value, the state may have changed. +func (f *Flock) Locked() bool { + f.m.RLock() + defer f.m.RUnlock() + return f.l +} + +// RLocked returns the read lock state (locked: true, unlocked: false). +// +// Warning: by the time you use the returned value, the state may have changed. +func (f *Flock) RLocked() bool { + f.m.RLock() + defer f.m.RUnlock() + return f.r +} + +func (f *Flock) String() string { + return f.path +} + +// TryLockContext repeatedly tries to take an exclusive lock until one of the +// conditions is met: TryLock succeeds, TryLock fails with error, or Context +// Done channel is closed. +func (f *Flock) TryLockContext(ctx context.Context, retryDelay time.Duration) (bool, error) { + return tryCtx(ctx, f.TryLock, retryDelay) +} + +// TryRLockContext repeatedly tries to take a shared lock until one of the +// conditions is met: TryRLock succeeds, TryRLock fails with error, or Context +// Done channel is closed. +func (f *Flock) TryRLockContext(ctx context.Context, retryDelay time.Duration) (bool, error) { + return tryCtx(ctx, f.TryRLock, retryDelay) +} + +func tryCtx(ctx context.Context, fn func() (bool, error), retryDelay time.Duration) (bool, error) { + if ctx.Err() != nil { + return false, ctx.Err() + } + for { + if ok, err := fn(); ok || err != nil { + return ok, err + } + select { + case <-ctx.Done(): + return false, ctx.Err() + case <-time.After(retryDelay): + // try again + } + } +} + +func (f *Flock) setFh() error { + // open a new os.File instance + // create it if it doesn't exist, and open the file read-only. + flags := os.O_CREATE + if runtime.GOOS == "aix" { + // AIX cannot preform write-lock (ie exclusive) on a + // read-only file. + flags |= os.O_RDWR + } else { + flags |= os.O_RDONLY + } + fh, err := os.OpenFile(f.path, flags, os.FileMode(0600)) + if err != nil { + return err + } + + // set the filehandle on the struct + f.fh = fh + return nil +} + +// ensure the file handle is closed if no lock is held +func (f *Flock) ensureFhState() { + if !f.l && !f.r && f.fh != nil { + f.fh.Close() + f.fh = nil + } +} diff --git a/vendor/github.com/gofrs/flock/flock_aix.go b/vendor/github.com/gofrs/flock/flock_aix.go new file mode 100644 index 00000000..7277c1b6 --- /dev/null +++ b/vendor/github.com/gofrs/flock/flock_aix.go @@ -0,0 +1,281 @@ +// Copyright 2019 Tim Heckman. All rights reserved. Use of this source code is +// governed by the BSD 3-Clause license that can be found in the LICENSE file. + +// Copyright 2018 The 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. + +// This code implements the filelock API using POSIX 'fcntl' locks, which attach +// to an (inode, process) pair rather than a file descriptor. To avoid unlocking +// files prematurely when the same file is opened through different descriptors, +// we allow only one read-lock at a time. +// +// This code is adapted from the Go package: +// cmd/go/internal/lockedfile/internal/filelock + +//+build aix + +package flock + +import ( + "errors" + "io" + "os" + "sync" + "syscall" + + "golang.org/x/sys/unix" +) + +type lockType int16 + +const ( + readLock lockType = unix.F_RDLCK + writeLock lockType = unix.F_WRLCK +) + +type cmdType int + +const ( + tryLock cmdType = unix.F_SETLK + waitLock cmdType = unix.F_SETLKW +) + +type inode = uint64 + +type inodeLock struct { + owner *Flock + queue []<-chan *Flock +} + +var ( + mu sync.Mutex + inodes = map[*Flock]inode{} + locks = map[inode]inodeLock{} +) + +// Lock is a blocking call to try and take an exclusive file lock. It will wait +// until it is able to obtain the exclusive file lock. It's recommended that +// TryLock() be used over this function. This function may block the ability to +// query the current Locked() or RLocked() status due to a RW-mutex lock. +// +// If we are already exclusive-locked, this function short-circuits and returns +// immediately assuming it can take the mutex lock. +// +// If the *Flock has a shared lock (RLock), this may transparently replace the +// shared lock with an exclusive lock on some UNIX-like operating systems. Be +// careful when using exclusive locks in conjunction with shared locks +// (RLock()), because calling Unlock() may accidentally release the exclusive +// lock that was once a shared lock. +func (f *Flock) Lock() error { + return f.lock(&f.l, writeLock) +} + +// RLock is a blocking call to try and take a shared file lock. It will wait +// until it is able to obtain the shared file lock. It's recommended that +// TryRLock() be used over this function. This function may block the ability to +// query the current Locked() or RLocked() status due to a RW-mutex lock. +// +// If we are already shared-locked, this function short-circuits and returns +// immediately assuming it can take the mutex lock. +func (f *Flock) RLock() error { + return f.lock(&f.r, readLock) +} + +func (f *Flock) lock(locked *bool, flag lockType) error { + f.m.Lock() + defer f.m.Unlock() + + if *locked { + return nil + } + + if f.fh == nil { + if err := f.setFh(); err != nil { + return err + } + defer f.ensureFhState() + } + + if _, err := f.doLock(waitLock, flag, true); err != nil { + return err + } + + *locked = true + return nil +} + +func (f *Flock) doLock(cmd cmdType, lt lockType, blocking bool) (bool, error) { + // POSIX locks apply per inode and process, and the lock for an inode is + // released when *any* descriptor for that inode is closed. So we need to + // synchronize access to each inode internally, and must serialize lock and + // unlock calls that refer to the same inode through different descriptors. + fi, err := f.fh.Stat() + if err != nil { + return false, err + } + ino := inode(fi.Sys().(*syscall.Stat_t).Ino) + + mu.Lock() + if i, dup := inodes[f]; dup && i != ino { + mu.Unlock() + return false, &os.PathError{ + Path: f.Path(), + Err: errors.New("inode for file changed since last Lock or RLock"), + } + } + + inodes[f] = ino + + var wait chan *Flock + l := locks[ino] + if l.owner == f { + // This file already owns the lock, but the call may change its lock type. + } else if l.owner == nil { + // No owner: it's ours now. + l.owner = f + } else if !blocking { + // Already owned: cannot take the lock. + mu.Unlock() + return false, nil + } else { + // Already owned: add a channel to wait on. + wait = make(chan *Flock) + l.queue = append(l.queue, wait) + } + locks[ino] = l + mu.Unlock() + + if wait != nil { + wait <- f + } + + err = setlkw(f.fh.Fd(), cmd, lt) + + if err != nil { + f.doUnlock() + if cmd == tryLock && err == unix.EACCES { + return false, nil + } + return false, err + } + + return true, nil +} + +func (f *Flock) Unlock() error { + f.m.Lock() + defer f.m.Unlock() + + // if we aren't locked or if the lockfile instance is nil + // just return a nil error because we are unlocked + if (!f.l && !f.r) || f.fh == nil { + return nil + } + + if err := f.doUnlock(); err != nil { + return err + } + + f.fh.Close() + + f.l = false + f.r = false + f.fh = nil + + return nil +} + +func (f *Flock) doUnlock() (err error) { + var owner *Flock + mu.Lock() + ino, ok := inodes[f] + if ok { + owner = locks[ino].owner + } + mu.Unlock() + + if owner == f { + err = setlkw(f.fh.Fd(), waitLock, unix.F_UNLCK) + } + + mu.Lock() + l := locks[ino] + if len(l.queue) == 0 { + // No waiters: remove the map entry. + delete(locks, ino) + } else { + // The first waiter is sending us their file now. + // Receive it and update the queue. + l.owner = <-l.queue[0] + l.queue = l.queue[1:] + locks[ino] = l + } + delete(inodes, f) + mu.Unlock() + + return err +} + +// TryLock is the preferred function for taking an exclusive file lock. This +// function takes an RW-mutex lock before it tries to lock the file, so there is +// the possibility that this function may block for a short time if another +// goroutine is trying to take any action. +// +// The actual file lock is non-blocking. If we are unable to get the exclusive +// file lock, the function will return false instead of waiting for the lock. If +// we get the lock, we also set the *Flock instance as being exclusive-locked. +func (f *Flock) TryLock() (bool, error) { + return f.try(&f.l, writeLock) +} + +// TryRLock is the preferred function for taking a shared file lock. This +// function takes an RW-mutex lock before it tries to lock the file, so there is +// the possibility that this function may block for a short time if another +// goroutine is trying to take any action. +// +// The actual file lock is non-blocking. If we are unable to get the shared file +// lock, the function will return false instead of waiting for the lock. If we +// get the lock, we also set the *Flock instance as being share-locked. +func (f *Flock) TryRLock() (bool, error) { + return f.try(&f.r, readLock) +} + +func (f *Flock) try(locked *bool, flag lockType) (bool, error) { + f.m.Lock() + defer f.m.Unlock() + + if *locked { + return true, nil + } + + if f.fh == nil { + if err := f.setFh(); err != nil { + return false, err + } + defer f.ensureFhState() + } + + haslock, err := f.doLock(tryLock, flag, false) + if err != nil { + return false, err + } + + *locked = haslock + return haslock, nil +} + +// setlkw calls FcntlFlock with cmd for the entire file indicated by fd. +func setlkw(fd uintptr, cmd cmdType, lt lockType) error { + for { + err := unix.FcntlFlock(fd, int(cmd), &unix.Flock_t{ + Type: int16(lt), + Whence: io.SeekStart, + Start: 0, + Len: 0, // All bytes. + }) + if err != unix.EINTR { + return err + } + } +} diff --git a/vendor/github.com/gofrs/flock/flock_unix.go b/vendor/github.com/gofrs/flock/flock_unix.go new file mode 100644 index 00000000..c315a3e2 --- /dev/null +++ b/vendor/github.com/gofrs/flock/flock_unix.go @@ -0,0 +1,197 @@ +// Copyright 2015 Tim Heckman. All rights reserved. +// Use of this source code is governed by the BSD 3-Clause +// license that can be found in the LICENSE file. + +// +build !aix,!windows + +package flock + +import ( + "os" + "syscall" +) + +// Lock is a blocking call to try and take an exclusive file lock. It will wait +// until it is able to obtain the exclusive file lock. It's recommended that +// TryLock() be used over this function. This function may block the ability to +// query the current Locked() or RLocked() status due to a RW-mutex lock. +// +// If we are already exclusive-locked, this function short-circuits and returns +// immediately assuming it can take the mutex lock. +// +// If the *Flock has a shared lock (RLock), this may transparently replace the +// shared lock with an exclusive lock on some UNIX-like operating systems. Be +// careful when using exclusive locks in conjunction with shared locks +// (RLock()), because calling Unlock() may accidentally release the exclusive +// lock that was once a shared lock. +func (f *Flock) Lock() error { + return f.lock(&f.l, syscall.LOCK_EX) +} + +// RLock is a blocking call to try and take a shared file lock. It will wait +// until it is able to obtain the shared file lock. It's recommended that +// TryRLock() be used over this function. This function may block the ability to +// query the current Locked() or RLocked() status due to a RW-mutex lock. +// +// If we are already shared-locked, this function short-circuits and returns +// immediately assuming it can take the mutex lock. +func (f *Flock) RLock() error { + return f.lock(&f.r, syscall.LOCK_SH) +} + +func (f *Flock) lock(locked *bool, flag int) error { + f.m.Lock() + defer f.m.Unlock() + + if *locked { + return nil + } + + if f.fh == nil { + if err := f.setFh(); err != nil { + return err + } + defer f.ensureFhState() + } + + if err := syscall.Flock(int(f.fh.Fd()), flag); err != nil { + shouldRetry, reopenErr := f.reopenFDOnError(err) + if reopenErr != nil { + return reopenErr + } + + if !shouldRetry { + return err + } + + if err = syscall.Flock(int(f.fh.Fd()), flag); err != nil { + return err + } + } + + *locked = true + return nil +} + +// Unlock is a function to unlock the file. This file takes a RW-mutex lock, so +// while it is running the Locked() and RLocked() functions will be blocked. +// +// This function short-circuits if we are unlocked already. If not, it calls +// syscall.LOCK_UN on the file and closes the file descriptor. It does not +// remove the file from disk. It's up to your application to do. +// +// Please note, if your shared lock became an exclusive lock this may +// unintentionally drop the exclusive lock if called by the consumer that +// believes they have a shared lock. Please see Lock() for more details. +func (f *Flock) Unlock() error { + f.m.Lock() + defer f.m.Unlock() + + // if we aren't locked or if the lockfile instance is nil + // just return a nil error because we are unlocked + if (!f.l && !f.r) || f.fh == nil { + return nil + } + + // mark the file as unlocked + if err := syscall.Flock(int(f.fh.Fd()), syscall.LOCK_UN); err != nil { + return err + } + + f.fh.Close() + + f.l = false + f.r = false + f.fh = nil + + return nil +} + +// TryLock is the preferred function for taking an exclusive file lock. This +// function takes an RW-mutex lock before it tries to lock the file, so there is +// the possibility that this function may block for a short time if another +// goroutine is trying to take any action. +// +// The actual file lock is non-blocking. If we are unable to get the exclusive +// file lock, the function will return false instead of waiting for the lock. If +// we get the lock, we also set the *Flock instance as being exclusive-locked. +func (f *Flock) TryLock() (bool, error) { + return f.try(&f.l, syscall.LOCK_EX) +} + +// TryRLock is the preferred function for taking a shared file lock. This +// function takes an RW-mutex lock before it tries to lock the file, so there is +// the possibility that this function may block for a short time if another +// goroutine is trying to take any action. +// +// The actual file lock is non-blocking. If we are unable to get the shared file +// lock, the function will return false instead of waiting for the lock. If we +// get the lock, we also set the *Flock instance as being share-locked. +func (f *Flock) TryRLock() (bool, error) { + return f.try(&f.r, syscall.LOCK_SH) +} + +func (f *Flock) try(locked *bool, flag int) (bool, error) { + f.m.Lock() + defer f.m.Unlock() + + if *locked { + return true, nil + } + + if f.fh == nil { + if err := f.setFh(); err != nil { + return false, err + } + defer f.ensureFhState() + } + + var retried bool +retry: + err := syscall.Flock(int(f.fh.Fd()), flag|syscall.LOCK_NB) + + switch err { + case syscall.EWOULDBLOCK: + return false, nil + case nil: + *locked = true + return true, nil + } + if !retried { + if shouldRetry, reopenErr := f.reopenFDOnError(err); reopenErr != nil { + return false, reopenErr + } else if shouldRetry { + retried = true + goto retry + } + } + + return false, err +} + +// reopenFDOnError determines whether we should reopen the file handle +// in readwrite mode and try again. This comes from util-linux/sys-utils/flock.c: +// Since Linux 3.4 (commit 55725513) +// Probably NFSv4 where flock() is emulated by fcntl(). +func (f *Flock) reopenFDOnError(err error) (bool, error) { + if err != syscall.EIO && err != syscall.EBADF { + return false, nil + } + if st, err := f.fh.Stat(); err == nil { + // if the file is able to be read and written + if st.Mode()&0600 == 0600 { + f.fh.Close() + f.fh = nil + + // reopen in read-write mode and set the filehandle + fh, err := os.OpenFile(f.path, os.O_CREATE|os.O_RDWR, os.FileMode(0600)) + if err != nil { + return false, err + } + f.fh = fh + return true, nil + } + } + + return false, nil +} diff --git a/vendor/github.com/gofrs/flock/flock_winapi.go b/vendor/github.com/gofrs/flock/flock_winapi.go new file mode 100644 index 00000000..fe405a25 --- /dev/null +++ b/vendor/github.com/gofrs/flock/flock_winapi.go @@ -0,0 +1,76 @@ +// Copyright 2015 Tim Heckman. All rights reserved. +// Use of this source code is governed by the BSD 3-Clause +// license that can be found in the LICENSE file. + +// +build windows + +package flock + +import ( + "syscall" + "unsafe" +) + +var ( + kernel32, _ = syscall.LoadLibrary("kernel32.dll") + procLockFileEx, _ = syscall.GetProcAddress(kernel32, "LockFileEx") + procUnlockFileEx, _ = syscall.GetProcAddress(kernel32, "UnlockFileEx") +) + +const ( + winLockfileFailImmediately = 0x00000001 + winLockfileExclusiveLock = 0x00000002 + winLockfileSharedLock = 0x00000000 +) + +// Use of 0x00000000 for the shared lock is a guess based on some the MS Windows +// `LockFileEX` docs, which document the `LOCKFILE_EXCLUSIVE_LOCK` flag as: +// +// > The function requests an exclusive lock. Otherwise, it requests a shared +// > lock. +// +// https://msdn.microsoft.com/en-us/library/windows/desktop/aa365203(v=vs.85).aspx + +func lockFileEx(handle syscall.Handle, flags uint32, reserved uint32, numberOfBytesToLockLow uint32, numberOfBytesToLockHigh uint32, offset *syscall.Overlapped) (bool, syscall.Errno) { + r1, _, errNo := syscall.Syscall6( + uintptr(procLockFileEx), + 6, + uintptr(handle), + uintptr(flags), + uintptr(reserved), + uintptr(numberOfBytesToLockLow), + uintptr(numberOfBytesToLockHigh), + uintptr(unsafe.Pointer(offset))) + + if r1 != 1 { + if errNo == 0 { + return false, syscall.EINVAL + } + + return false, errNo + } + + return true, 0 +} + +func unlockFileEx(handle syscall.Handle, reserved uint32, numberOfBytesToLockLow uint32, numberOfBytesToLockHigh uint32, offset *syscall.Overlapped) (bool, syscall.Errno) { + r1, _, errNo := syscall.Syscall6( + uintptr(procUnlockFileEx), + 5, + uintptr(handle), + uintptr(reserved), + uintptr(numberOfBytesToLockLow), + uintptr(numberOfBytesToLockHigh), + uintptr(unsafe.Pointer(offset)), + 0) + + if r1 != 1 { + if errNo == 0 { + return false, syscall.EINVAL + } + + return false, errNo + } + + return true, 0 +} diff --git a/vendor/github.com/gofrs/flock/flock_windows.go b/vendor/github.com/gofrs/flock/flock_windows.go new file mode 100644 index 00000000..ddb534cc --- /dev/null +++ b/vendor/github.com/gofrs/flock/flock_windows.go @@ -0,0 +1,142 @@ +// Copyright 2015 Tim Heckman. All rights reserved. +// Use of this source code is governed by the BSD 3-Clause +// license that can be found in the LICENSE file. + +package flock + +import ( + "syscall" +) + +// ErrorLockViolation is the error code returned from the Windows syscall when a +// lock would block and you ask to fail immediately. +const ErrorLockViolation syscall.Errno = 0x21 // 33 + +// Lock is a blocking call to try and take an exclusive file lock. It will wait +// until it is able to obtain the exclusive file lock. It's recommended that +// TryLock() be used over this function. This function may block the ability to +// query the current Locked() or RLocked() status due to a RW-mutex lock. +// +// If we are already locked, this function short-circuits and returns +// immediately assuming it can take the mutex lock. +func (f *Flock) Lock() error { + return f.lock(&f.l, winLockfileExclusiveLock) +} + +// RLock is a blocking call to try and take a shared file lock. It will wait +// until it is able to obtain the shared file lock. It's recommended that +// TryRLock() be used over this function. This function may block the ability to +// query the current Locked() or RLocked() status due to a RW-mutex lock. +// +// If we are already locked, this function short-circuits and returns +// immediately assuming it can take the mutex lock. +func (f *Flock) RLock() error { + return f.lock(&f.r, winLockfileSharedLock) +} + +func (f *Flock) lock(locked *bool, flag uint32) error { + f.m.Lock() + defer f.m.Unlock() + + if *locked { + return nil + } + + if f.fh == nil { + if err := f.setFh(); err != nil { + return err + } + defer f.ensureFhState() + } + + if _, errNo := lockFileEx(syscall.Handle(f.fh.Fd()), flag, 0, 1, 0, &syscall.Overlapped{}); errNo > 0 { + return errNo + } + + *locked = true + return nil +} + +// Unlock is a function to unlock the file. This file takes a RW-mutex lock, so +// while it is running the Locked() and RLocked() functions will be blocked. +// +// This function short-circuits if we are unlocked already. If not, it calls +// UnlockFileEx() on the file and closes the file descriptor. It does not remove +// the file from disk. It's up to your application to do. +func (f *Flock) Unlock() error { + f.m.Lock() + defer f.m.Unlock() + + // if we aren't locked or if the lockfile instance is nil + // just return a nil error because we are unlocked + if (!f.l && !f.r) || f.fh == nil { + return nil + } + + // mark the file as unlocked + if _, errNo := unlockFileEx(syscall.Handle(f.fh.Fd()), 0, 1, 0, &syscall.Overlapped{}); errNo > 0 { + return errNo + } + + f.fh.Close() + + f.l = false + f.r = false + f.fh = nil + + return nil +} + +// TryLock is the preferred function for taking an exclusive file lock. This +// function does take a RW-mutex lock before it tries to lock the file, so there +// is the possibility that this function may block for a short time if another +// goroutine is trying to take any action. +// +// The actual file lock is non-blocking. If we are unable to get the exclusive +// file lock, the function will return false instead of waiting for the lock. If +// we get the lock, we also set the *Flock instance as being exclusive-locked. +func (f *Flock) TryLock() (bool, error) { + return f.try(&f.l, winLockfileExclusiveLock) +} + +// TryRLock is the preferred function for taking a shared file lock. This +// function does take a RW-mutex lock before it tries to lock the file, so there +// is the possibility that this function may block for a short time if another +// goroutine is trying to take any action. +// +// The actual file lock is non-blocking. If we are unable to get the shared file +// lock, the function will return false instead of waiting for the lock. If we +// get the lock, we also set the *Flock instance as being shared-locked. +func (f *Flock) TryRLock() (bool, error) { + return f.try(&f.r, winLockfileSharedLock) +} + +func (f *Flock) try(locked *bool, flag uint32) (bool, error) { + f.m.Lock() + defer f.m.Unlock() + + if *locked { + return true, nil + } + + if f.fh == nil { + if err := f.setFh(); err != nil { + return false, err + } + defer f.ensureFhState() + } + + _, errNo := lockFileEx(syscall.Handle(f.fh.Fd()), flag|winLockfileFailImmediately, 0, 1, 0, &syscall.Overlapped{}) + + if errNo > 0 { + if errNo == ErrorLockViolation || errNo == syscall.ERROR_IO_PENDING { + return false, nil + } + + return false, errNo + } + + *locked = true + + return true, nil +} diff --git a/vendor/modules.txt b/vendor/modules.txt index 1bf5ec77..fef02789 100644 --- a/vendor/modules.txt +++ b/vendor/modules.txt @@ -27,6 +27,9 @@ github.com/ergochat/irc-go/ircutils github.com/go-sql-driver/mysql # github.com/go-test/deep v1.0.6 ## explicit; go 1.13 +# github.com/gofrs/flock v0.8.1 +## explicit +github.com/gofrs/flock # github.com/golang-jwt/jwt v3.2.2+incompatible ## explicit github.com/golang-jwt/jwt