Merge pull request #3437 from giuseppe/fix-nocgo

build: allow to build without cgo on RISC-V

9 files changed, 544 insertions, 34 deletions

diff --git a/libpod/container_attach_linux.go b/libpod/container_attach_linux.go
index f5aac5794..fc53268c3 100644
--- a/libpod/container_attach_linux.go
+++ b/libpod/container_attach_linux.go
@@ -19,10 +19,6 @@ import (
 	"k8s.io/client-go/tools/remotecommand"
 )
 
-//#include <sys/un.h>
-// extern int unix_path_length(){struct sockaddr_un addr; return sizeof(addr.sun_path) - 1;}
-import "C"
-
 /* Sync with stdpipe_t in conmon.c */
 const (
 	AttachPipeStdin  = 1
@@ -80,7 +76,7 @@ func (c *Container) attachContainerSocket(resize <-chan remotecommand.TerminalSi
 
 	socketPath := c.AttachSocketPath()
 
-	maxUnixLength := int(C.unix_path_length())
+	maxUnixLength := unixPathLength()
 	if maxUnixLength < len(socketPath) {
 		socketPath = socketPath[0:maxUnixLength]
 	}
diff --git a/libpod/container_attach_linux_cgo.go b/libpod/container_attach_linux_cgo.go
new file mode 100644
index 000000000..d81243360
--- /dev/null
+++ b/libpod/container_attach_linux_cgo.go
@@ -0,0 +1,11 @@
+//+build linux,cgo
+
+package libpod
+
+//#include <sys/un.h>
+// extern int unix_path_length(){struct sockaddr_un addr; return sizeof(addr.sun_path) - 1;}
+import "C"
+
+func unixPathLength() int {
+	return int(C.unix_path_length())
+}
diff --git a/libpod/container_attach_linux_nocgo.go b/libpod/container_attach_linux_nocgo.go
new file mode 100644
index 000000000..a514a555d
--- /dev/null
+++ b/libpod/container_attach_linux_nocgo.go
@@ -0,0 +1,7 @@
+//+build linux,!cgo
+
+package libpod
+
+func unixPathLength() int {
+	return 107
+}
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/lock/shm/shm_lock.go b/libpod/lock/shm/shm_lock.go
index 76dd5729e..37c8dea7d 100644
--- a/libpod/lock/shm/shm_lock.go
+++ b/libpod/lock/shm/shm_lock.go
@@ -1,3 +1,5 @@
+// +build linux,cgo
+
 package shm
 
 // #cgo LDFLAGS: -lrt -lpthread
diff --git a/libpod/lock/shm/shm_lock_nocgo.go b/libpod/lock/shm/shm_lock_nocgo.go
new file mode 100644
index 000000000..ea1488c90
--- /dev/null
+++ b/libpod/lock/shm/shm_lock_nocgo.go
@@ -0,0 +1,102 @@
+// +build linux,!cgo
+
+package shm
+
+import (
+	"github.com/sirupsen/logrus"
+)
+
+// SHMLocks is a struct enabling POSIX semaphore locking in a shared memory
+// segment.
+type SHMLocks struct {
+}
+
+// CreateSHMLock sets up a shared-memory segment holding a given number of POSIX
+// semaphores, and returns a struct that can be used to operate on those locks.
+// numLocks must not be 0, and may be rounded up to a multiple of the bitmap
+// size used by the underlying implementation.
+func CreateSHMLock(path string, numLocks uint32) (*SHMLocks, error) {
+	logrus.Error("locks are not supported without cgo")
+	return &SHMLocks{}, nil
+}
+
+// OpenSHMLock opens an existing shared-memory segment holding a given number of
+// POSIX semaphores. numLocks must match the number of locks the shared memory
+// segment was created with.
+func OpenSHMLock(path string, numLocks uint32) (*SHMLocks, error) {
+	logrus.Error("locks are not supported without cgo")
+	return &SHMLocks{}, nil
+}
+
+// GetMaxLocks returns the maximum number of locks in the SHM
+func (locks *SHMLocks) GetMaxLocks() uint32 {
+	logrus.Error("locks are not supported without cgo")
+	return 0
+}
+
+// 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 *SHMLocks) Close() error {
+	logrus.Error("locks are not supported without cgo")
+	return nil
+}
+
+// AllocateSemaphore allocates a semaphore from a shared-memory segment for use
+// by a container or pod.
+// Returns the index of the semaphore that was allocated.
+// Allocations past the maximum number of locks given when the SHM segment was
+// created will result in an error, and no semaphore will be allocated.
+func (locks *SHMLocks) AllocateSemaphore() (uint32, error) {
+	logrus.Error("locks are not supported without cgo")
+	return 0, nil
+}
+
+// AllocateGivenSemaphore allocates the given semaphore from the shared-memory
+// segment for use by a container or pod.
+// If the semaphore is already in use or the index is invalid an error will be
+// returned.
+func (locks *SHMLocks) AllocateGivenSemaphore(sem uint32) error {
+	logrus.Error("locks are not supported without cgo")
+	return nil
+}
+
+// DeallocateSemaphore frees a semaphore in a shared-memory segment so it can be
+// reallocated to another container or pod.
+// The given semaphore must be already allocated, or an error will be returned.
+func (locks *SHMLocks) DeallocateSemaphore(sem uint32) error {
+	logrus.Error("locks are not supported without cgo")
+	return nil
+}
+
+// DeallocateAllSemaphores frees all semaphores so they can be reallocated to
+// other containers and pods.
+func (locks *SHMLocks) DeallocateAllSemaphores() error {
+	logrus.Error("locks are not supported without cgo")
+	return nil
+}
+
+// LockSemaphore locks the given semaphore.
+// If the semaphore is already locked, LockSemaphore will block until the lock
+// can be acquired.
+// There is no requirement that the given semaphore be allocated.
+// This ensures that attempts to lock a container after it has been deleted,
+// but before the caller has queried the database to determine this, will
+// succeed.
+func (locks *SHMLocks) LockSemaphore(sem uint32) error {
+	logrus.Error("locks are not supported without cgo")
+	return nil
+}
+
+// UnlockSemaphore unlocks the given semaphore.
+// Unlocking a semaphore that is already unlocked with return EBUSY.
+// There is no requirement that the given semaphore be allocated.
+// This ensures that attempts to lock a container after it has been deleted,
+// but before the caller has queried the database to determine this, will
+// succeed.
+func (locks *SHMLocks) UnlockSemaphore(sem uint32) error {
+	logrus.Error("locks are not supported without cgo")
+	return nil
+}
diff --git a/libpod/runtime.go b/libpod/runtime.go
index e358fe4c4..6c61e15d3 100644
--- a/libpod/runtime.go
+++ b/libpod/runtime.go
@@ -239,6 +239,9 @@ type RuntimeConfig struct {
 	// pods.
 	NumLocks uint32 `toml:"num_locks,omitempty"`
 
+	// LockType is the type of locking to use.
+	LockType string `toml:"lock_type,omitempty"`
+
 	// EventsLogger determines where events should be logged
 	EventsLogger string `toml:"events_logger"`
 	// EventsLogFilePath is where the events log is stored.
@@ -318,6 +321,7 @@ func defaultRuntimeConfig() (RuntimeConfig, error) {
 		NumLocks:              2048,
 		EventsLogger:          events.DefaultEventerType.String(),
 		DetachKeys:            DefaultDetachKeys,
+		LockType:              "shm",
 	}, nil
 }
 
@@ -659,6 +663,62 @@ func newRuntimeFromConfig(ctx context.Context, userConfigPath string, options ..
 	return runtime, nil
 }
 
+func getLockManager(runtime *Runtime) (lock.Manager, error) {
+	var err 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() {
+			lockPath = fmt.Sprintf("%s_%d", DefaultRootlessSHMLockPath, rootless.GetRootlessUID())
+		}
+		// Set up the lock manager
+		manager, err = lock.OpenSHMLockManager(lockPath, runtime.config.NumLocks)
+		if err != nil {
+			if os.IsNotExist(errors.Cause(err)) {
+				manager, err = lock.NewSHMLockManager(lockPath, runtime.config.NumLocks)
+				if err != nil {
+					return nil, errors.Wrapf(err, "failed to get new shm lock manager")
+				}
+			} else if errors.Cause(err) == syscall.ERANGE && runtime.doRenumber {
+				logrus.Debugf("Number of locks does not match - removing old locks")
+
+				// ERANGE indicates a lock numbering mismatch.
+				// Since we're renumbering, this is not fatal.
+				// Remove the earlier set of locks and recreate.
+				if err := os.Remove(filepath.Join("/dev/shm", lockPath)); err != nil {
+					return nil, errors.Wrapf(err, "error removing libpod locks file %s", lockPath)
+				}
+
+				manager, err = lock.NewSHMLockManager(lockPath, runtime.config.NumLocks)
+				if err != nil {
+					return nil, err
+				}
+			} else {
+				return nil, err
+			}
+		}
+	default:
+		return nil, errors.Wrapf(define.ErrInvalidArg, "unknown lock type %s", runtime.config.LockType)
+	}
+	return manager, nil
+}
+
 // Make a new runtime based on the given configuration
 // Sets up containers/storage, state store, OCI runtime
 func makeRuntime(ctx context.Context, runtime *Runtime) (err error) {
@@ -1044,37 +1104,10 @@ func makeRuntime(ctx context.Context, runtime *Runtime) (err error) {
 		}
 	}
 
-	lockPath := DefaultSHMLockPath
-	if rootless.IsRootless() {
-		lockPath = fmt.Sprintf("%s_%d", DefaultRootlessSHMLockPath, rootless.GetRootlessUID())
-	}
-	// Set up the lock manager
-	manager, err := lock.OpenSHMLockManager(lockPath, runtime.config.NumLocks)
+	runtime.lockManager, err = getLockManager(runtime)
 	if err != nil {
-		if os.IsNotExist(errors.Cause(err)) {
-			manager, err = lock.NewSHMLockManager(lockPath, runtime.config.NumLocks)
-			if err != nil {
-				return errors.Wrapf(err, "failed to get new shm lock manager")
-			}
-		} else if errors.Cause(err) == syscall.ERANGE && runtime.doRenumber {
-			logrus.Debugf("Number of locks does not match - removing old locks")
-
-			// ERANGE indicates a lock numbering mismatch.
-			// Since we're renumbering, this is not fatal.
-			// Remove the earlier set of locks and recreate.
-			if err := os.Remove(filepath.Join("/dev/shm", lockPath)); err != nil {
-				return errors.Wrapf(err, "error removing libpod locks file %s", lockPath)
-			}
-
-			manager, err = lock.NewSHMLockManager(lockPath, runtime.config.NumLocks)
-			if err != nil {
-				return err
-			}
-		} else {
-			return err
-		}
+		return err
 	}
-	runtime.lockManager = manager
 
 	// If we're renumbering locks, do it now.
 	// It breaks out of normal runtime init, and will not return a valid