From 827ac0859f9649a971c6d4092fcd26158afa5478 Mon Sep 17 00:00:00 2001 From: Giuseppe Scrivano Date: Thu, 27 Jun 2019 12:56:29 +0200 Subject: lock: new lock type "file" it is a wrapper around containers/storage file locking. Signed-off-by: Giuseppe Scrivano --- libpod/lock/file/file_lock.go | 175 +++++++++++++++++++++++++++++++++++++ libpod/lock/file/file_lock_test.go | 74 ++++++++++++++++ libpod/lock/file_lock_manager.go | 110 +++++++++++++++++++++++ libpod/runtime.go | 15 ++++ 4 files changed, 374 insertions(+) create mode 100644 libpod/lock/file/file_lock.go create mode 100644 libpod/lock/file/file_lock_test.go create mode 100644 libpod/lock/file_lock_manager.go (limited to 'libpod') diff --git a/libpod/lock/file/file_lock.go b/libpod/lock/file/file_lock.go new file mode 100644 index 000000000..e50d67321 --- /dev/null +++ b/libpod/lock/file/file_lock.go @@ -0,0 +1,175 @@ +package file + +import ( + "io/ioutil" + "os" + "path/filepath" + "strconv" + "syscall" + + "github.com/containers/storage" + "github.com/pkg/errors" + "github.com/sirupsen/logrus" +) + +// FileLocks is a struct enabling POSIX lock locking in a shared memory +// segment. +type FileLocks struct { // nolint + lockPath string + valid bool +} + +// CreateFileLock sets up a directory containing the various lock files. +func CreateFileLock(path string) (*FileLocks, error) { + _, err := os.Stat(path) + if err == nil { + return nil, errors.Wrapf(syscall.EEXIST, "directory %s exists", path) + } + if err := os.MkdirAll(path, 0711); err != nil { + return nil, errors.Wrapf(err, "cannot create %s", path) + } + + locks := new(FileLocks) + locks.lockPath = path + locks.valid = true + + return locks, nil +} + +// OpenFileLock opens an existing directory with the lock files. +func OpenFileLock(path string) (*FileLocks, error) { + _, err := os.Stat(path) + if err != nil { + return nil, errors.Wrapf(err, "accessing directory %s", path) + } + + locks := new(FileLocks) + locks.lockPath = path + locks.valid = true + + return locks, nil +} + +// Close closes an existing shared-memory segment. +// The segment will be rendered unusable after closing. +// WARNING: If you Close() while there are still locks locked, these locks may +// fail to release, causing a program freeze. +// Close() is only intended to be used while testing the locks. +func (locks *FileLocks) Close() error { + if !locks.valid { + return errors.Wrapf(syscall.EINVAL, "locks have already been closed") + } + err := os.RemoveAll(locks.lockPath) + if err != nil { + return errors.Wrapf(err, "deleting directory %s", locks.lockPath) + } + return nil +} + +func (locks *FileLocks) getLockPath(lck uint32) string { + return filepath.Join(locks.lockPath, strconv.FormatInt(int64(lck), 10)) +} + +// AllocateLock allocates a lock and returns the index of the lock that was allocated. +func (locks *FileLocks) AllocateLock() (uint32, error) { + if !locks.valid { + return 0, errors.Wrapf(syscall.EINVAL, "locks have already been closed") + } + + id := uint32(0) + for ; ; id++ { + path := locks.getLockPath(id) + f, err := os.OpenFile(path, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0666) + if err != nil { + if os.IsExist(err) { + continue + } + return 0, errors.Wrapf(err, "creating lock file") + } + f.Close() + break + } + return id, nil +} + +// AllocateGivenLock allocates the given lock from the shared-memory +// segment for use by a container or pod. +// If the lock is already in use or the index is invalid an error will be +// returned. +func (locks *FileLocks) AllocateGivenLock(lck uint32) error { + if !locks.valid { + return errors.Wrapf(syscall.EINVAL, "locks have already been closed") + } + + f, err := os.OpenFile(locks.getLockPath(lck), os.O_RDWR|os.O_CREATE|os.O_EXCL, 0666) + if err != nil { + return errors.Wrapf(err, "error creating lock %d", lck) + } + f.Close() + + return nil +} + +// DeallocateLock frees a lock in a shared-memory segment so it can be +// reallocated to another container or pod. +// The given lock must be already allocated, or an error will be returned. +func (locks *FileLocks) DeallocateLock(lck uint32) error { + if !locks.valid { + return errors.Wrapf(syscall.EINVAL, "locks have already been closed") + } + if err := os.Remove(locks.getLockPath(lck)); err != nil { + return errors.Wrapf(err, "deallocating lock %d", lck) + } + return nil +} + +// DeallocateAllLocks frees all locks so they can be reallocated to +// other containers and pods. +func (locks *FileLocks) DeallocateAllLocks() error { + if !locks.valid { + return errors.Wrapf(syscall.EINVAL, "locks have already been closed") + } + files, err := ioutil.ReadDir(locks.lockPath) + if err != nil { + return errors.Wrapf(err, "error reading directory %s", locks.lockPath) + } + var lastErr error + for _, f := range files { + p := filepath.Join(locks.lockPath, f.Name()) + err := os.Remove(p) + if err != nil { + lastErr = err + logrus.Errorf("deallocating lock %s", p) + } + } + return lastErr +} + +// LockFileLock locks the given lock. +func (locks *FileLocks) LockFileLock(lck uint32) error { + if !locks.valid { + return errors.Wrapf(syscall.EINVAL, "locks have already been closed") + } + + l, err := storage.GetLockfile(locks.getLockPath(lck)) + if err != nil { + return errors.Wrapf(err, "error acquiring lock") + } + + l.Lock() + return nil +} + +// UnlockFileLock unlocks the given lock. +func (locks *FileLocks) UnlockFileLock(lck uint32) error { + if !locks.valid { + return errors.Wrapf(syscall.EINVAL, "locks have already been closed") + } + l, err := storage.GetLockfile(locks.getLockPath(lck)) + if err != nil { + return errors.Wrapf(err, "error acquiring lock") + } + + l.Unlock() + return nil +} diff --git a/libpod/lock/file/file_lock_test.go b/libpod/lock/file/file_lock_test.go new file mode 100644 index 000000000..6320d6b70 --- /dev/null +++ b/libpod/lock/file/file_lock_test.go @@ -0,0 +1,74 @@ +package file + +import ( + "fmt" + "io/ioutil" + "os" + "os/exec" + "path/filepath" + "testing" + + "github.com/stretchr/testify/assert" +) + +// Test that creating and destroying locks work +func TestCreateAndDeallocate(t *testing.T) { + d, err := ioutil.TempDir("", "filelock") + assert.NoError(t, err) + defer os.RemoveAll(d) + + l, err := OpenFileLock(filepath.Join(d, "locks")) + assert.Error(t, err) + + l, err = CreateFileLock(filepath.Join(d, "locks")) + assert.NoError(t, err) + + lock, err := l.AllocateLock() + assert.NoError(t, err) + + err = l.AllocateGivenLock(lock) + assert.Error(t, err) + + err = l.DeallocateLock(lock) + assert.NoError(t, err) + + err = l.AllocateGivenLock(lock) + assert.NoError(t, err) + + err = l.DeallocateAllLocks() + assert.NoError(t, err) + + err = l.AllocateGivenLock(lock) + assert.NoError(t, err) + + err = l.DeallocateAllLocks() + assert.NoError(t, err) +} + +// Test that creating and destroying locks work +func TestLockAndUnlock(t *testing.T) { + d, err := ioutil.TempDir("", "filelock") + assert.NoError(t, err) + defer os.RemoveAll(d) + + l, err := CreateFileLock(filepath.Join(d, "locks")) + assert.NoError(t, err) + + lock, err := l.AllocateLock() + assert.NoError(t, err) + + err = l.LockFileLock(lock) + assert.NoError(t, err) + + lslocks, err := exec.LookPath("lslocks") + if err == nil { + lockPath := l.getLockPath(lock) + out, err := exec.Command(lslocks, "--json", "-p", fmt.Sprintf("%d", os.Getpid())).CombinedOutput() + assert.NoError(t, err) + + assert.Contains(t, string(out), lockPath) + } + + err = l.UnlockFileLock(lock) + assert.NoError(t, err) +} diff --git a/libpod/lock/file_lock_manager.go b/libpod/lock/file_lock_manager.go new file mode 100644 index 000000000..8a4d939d3 --- /dev/null +++ b/libpod/lock/file_lock_manager.go @@ -0,0 +1,110 @@ +package lock + +import ( + "github.com/containers/libpod/libpod/lock/file" +) + +// FileLockManager manages shared memory locks. +type FileLockManager struct { + locks *file.FileLocks +} + +// NewFileLockManager makes a new FileLockManager at the specified directory. +func NewFileLockManager(lockPath string) (Manager, error) { + locks, err := file.CreateFileLock(lockPath) + if err != nil { + return nil, err + } + + manager := new(FileLockManager) + manager.locks = locks + + return manager, nil +} + +// OpenFileLockManager opens an existing FileLockManager at the specified directory. +func OpenFileLockManager(path string) (Manager, error) { + locks, err := file.OpenFileLock(path) + if err != nil { + return nil, err + } + + manager := new(FileLockManager) + manager.locks = locks + + return manager, nil +} + +// AllocateLock allocates a new lock from the manager. +func (m *FileLockManager) AllocateLock() (Locker, error) { + semIndex, err := m.locks.AllocateLock() + if err != nil { + return nil, err + } + + lock := new(FileLock) + lock.lockID = semIndex + lock.manager = m + + return lock, nil +} + +// AllocateAndRetrieveLock allocates the lock with the given ID and returns it. +// If the lock is already allocated, error. +func (m *FileLockManager) AllocateAndRetrieveLock(id uint32) (Locker, error) { + lock := new(FileLock) + lock.lockID = id + lock.manager = m + + if err := m.locks.AllocateGivenLock(id); err != nil { + return nil, err + } + + return lock, nil +} + +// RetrieveLock retrieves a lock from the manager given its ID. +func (m *FileLockManager) RetrieveLock(id uint32) (Locker, error) { + lock := new(FileLock) + lock.lockID = id + lock.manager = m + + return lock, nil +} + +// FreeAllLocks frees all locks in the manager. +// This function is DANGEROUS. Please read the full comment in locks.go before +// trying to use it. +func (m *FileLockManager) FreeAllLocks() error { + return m.locks.DeallocateAllLocks() +} + +// FileLock is an individual shared memory lock. +type FileLock struct { + lockID uint32 + manager *FileLockManager +} + +// ID returns the ID of the lock. +func (l *FileLock) ID() uint32 { + return l.lockID +} + +// Lock acquires the lock. +func (l *FileLock) Lock() { + if err := l.manager.locks.LockFileLock(l.lockID); err != nil { + panic(err.Error()) + } +} + +// Unlock releases the lock. +func (l *FileLock) Unlock() { + if err := l.manager.locks.UnlockFileLock(l.lockID); err != nil { + panic(err.Error()) + } +} + +// Free releases the lock, allowing it to be reused. +func (l *FileLock) Free() error { + return l.manager.locks.DeallocateLock(l.lockID) +} diff --git a/libpod/runtime.go b/libpod/runtime.go index e8442f4a1..ca10f9243 100644 --- a/libpod/runtime.go +++ b/libpod/runtime.go @@ -318,6 +318,7 @@ func defaultRuntimeConfig() (RuntimeConfig, error) { NumLocks: 2048, EventsLogger: events.DefaultEventerType.String(), DetachKeys: DefaultDetachKeys, + LockType: "shm", }, nil } @@ -664,6 +665,20 @@ func getLockManager(runtime *Runtime) (lock.Manager, error) { var manager lock.Manager switch runtime.config.LockType { + case "file": + lockPath := filepath.Join(runtime.config.TmpDir, "locks") + manager, err = lock.OpenFileLockManager(lockPath) + if err != nil { + if os.IsNotExist(errors.Cause(err)) { + manager, err = lock.NewFileLockManager(lockPath) + if err != nil { + return nil, errors.Wrapf(err, "failed to get new file lock manager") + } + } else { + return nil, err + } + } + case "", "shm": lockPath := DefaultSHMLockPath if rootless.IsRootless() { -- cgit v1.2.3-54-g00ecf