forked from kata-containers/runtime
/
filesystem_backend.go
355 lines (281 loc) · 8.09 KB
/
filesystem_backend.go
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// Copyright (c) 2019 Intel Corporation
//
// SPDX-License-Identifier: Apache-2.0
//
package store
import (
"context"
"encoding/json"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"syscall"
"github.com/kata-containers/runtime/virtcontainers/pkg/rootless"
"github.com/kata-containers/runtime/virtcontainers/pkg/uuid"
opentracing "github.com/opentracing/opentracing-go"
"github.com/sirupsen/logrus"
)
const (
// ConfigurationFile is the file name used for every JSON sandbox configuration.
ConfigurationFile string = "config.json"
// StateFile is the file name storing a sandbox state.
StateFile = "state.json"
// NetworkFile is the file name storing a sandbox network.
NetworkFile = "network.json"
// HypervisorFile is the file name storing a hypervisor's state.
HypervisorFile = "hypervisor.json"
// AgentFile is the file name storing an agent's state.
AgentFile = "agent.json"
// ProcessFile is the file name storing a container process.
ProcessFile = "process.json"
// LockFile is the file name locking the usage of a resource.
LockFile = "lock"
// MountsFile is the file name storing a container's mount points.
MountsFile = "mounts.json"
// DevicesFile is the file name storing a container's devices.
DevicesFile = "devices.json"
// uuidFile is the file name storing a guest VM uuid state.
uuidFile = "uuid.json"
)
// DirMode is the permission bits used for creating a directory
const DirMode = os.FileMode(0750) | os.ModeDir
// StoragePathSuffix is the suffix used for all storage paths
//
// Note: this very brief path represents "virtcontainers". It is as
// terse as possible to minimise path length.
const StoragePathSuffix = "vc"
// SandboxPathSuffix is the suffix used for sandbox storage
const SandboxPathSuffix = "sbs"
// VMPathSuffix is the suffix used for guest VMs.
const VMPathSuffix = "vm"
// UUIDPathSuffix is the suffix used for uuid storage
const UUIDPathSuffix = "uuid"
// ConfigStoragePath is the sandbox configuration directory.
// It will contain one config.json file for each created sandbox.
// The function is declared this way for mocking in unit tests
var ConfigStoragePath = func() string {
path := filepath.Join("/var/lib", StoragePathSuffix, SandboxPathSuffix)
if rootless.IsRootless() {
return filepath.Join(rootless.GetRootlessDir(), path)
}
return path
}
// RunStoragePath is the sandbox runtime directory.
// It will contain one state.json and one lock file for each created sandbox.
// The function is declared this way for mocking in unit tests
var RunStoragePath = func() string {
path := filepath.Join("/run", StoragePathSuffix, SandboxPathSuffix)
if rootless.IsRootless() {
return filepath.Join(rootless.GetRootlessDir(), path)
}
return path
}
// RunVMStoragePath is the vm directory.
// It will contain all guest vm sockets and shared mountpoints.
// The function is declared this way for mocking in unit tests
var RunVMStoragePath = func() string {
path := filepath.Join("/run", StoragePathSuffix, VMPathSuffix)
if rootless.IsRootless() {
return filepath.Join(rootless.GetRootlessDir(), path)
}
return path
}
// VMUUIDStoragePath is the uuid directory.
// It will contain all uuid info used by guest vm.
var VMUUIDStoragePath = func() string {
path := filepath.Join("/var/lib", StoragePathSuffix, UUIDPathSuffix)
if rootless.IsRootless() {
return filepath.Join(rootless.GetRootlessDir(), path)
}
return path
}
func itemToFile(item Item) (string, error) {
switch item {
case Configuration:
return ConfigurationFile, nil
case State:
return StateFile, nil
case Network:
return NetworkFile, nil
case Hypervisor:
return HypervisorFile, nil
case Agent:
return AgentFile, nil
case Process:
return ProcessFile, nil
case Lock:
return LockFile, nil
case Mounts:
return MountsFile, nil
case Devices, DeviceIDs:
return DevicesFile, nil
case UUID:
return uuidFile, nil
}
return "", fmt.Errorf("Unknown item %s", item)
}
type filesystem struct {
ctx context.Context
path string
rawPath string
lockTokens map[string]*os.File
}
// Logger returns a logrus logger appropriate for logging Store filesystem messages
func (f *filesystem) logger() *logrus.Entry {
return storeLog.WithFields(logrus.Fields{
"subsystem": "store",
"backend": "filesystem",
"path": f.path,
})
}
func (f *filesystem) trace(name string) (opentracing.Span, context.Context) {
if f.ctx == nil {
f.logger().WithField("type", "bug").Error("trace called before context set")
f.ctx = context.Background()
}
span, ctx := opentracing.StartSpanFromContext(f.ctx, name)
span.SetTag("subsystem", "store")
span.SetTag("type", "filesystem")
span.SetTag("path", f.path)
return span, ctx
}
func (f *filesystem) itemToPath(item Item) (string, error) {
fileName, err := itemToFile(item)
if err != nil {
return "", err
}
return filepath.Join(f.path, fileName), nil
}
func (f *filesystem) initialize() error {
_, err := os.Stat(f.path)
if err == nil {
return nil
}
// Our root path does not exist, we need to create the initial layout:
// The root directory, a lock file and a raw files directory.
// Root directory
f.logger().WithField("path", f.path).Debugf("Creating root directory")
if err := os.MkdirAll(f.path, DirMode); err != nil {
return err
}
// Raw directory
f.logger().WithField("path", f.rawPath).Debugf("Creating raw directory")
if err := os.MkdirAll(f.rawPath, DirMode); err != nil {
return err
}
// Lock
lockPath := filepath.Join(f.path, LockFile)
lockFile, err := os.Create(lockPath)
if err != nil {
f.delete()
return err
}
lockFile.Close()
return nil
}
func (f *filesystem) new(ctx context.Context, path string, host string) error {
f.ctx = ctx
f.path = path
f.rawPath = filepath.Join(f.path, "raw")
f.lockTokens = make(map[string]*os.File)
f.logger().Debugf("New filesystem store backend for %s", path)
return f.initialize()
}
func (f *filesystem) delete() error {
f.logger().WithField("path", f.path).Debugf("Deleting files")
return os.RemoveAll(f.path)
}
func (f *filesystem) load(item Item, data interface{}) error {
span, _ := f.trace("load")
defer span.Finish()
span.SetTag("item", item)
filePath, err := f.itemToPath(item)
if err != nil {
return err
}
fileData, err := ioutil.ReadFile(filePath)
if err != nil {
return err
}
if err := json.Unmarshal(fileData, data); err != nil {
return err
}
return nil
}
func (f *filesystem) store(item Item, data interface{}) error {
span, _ := f.trace("store")
defer span.Finish()
span.SetTag("item", item)
filePath, err := f.itemToPath(item)
if err != nil {
return err
}
file, err := os.Create(filePath)
if err != nil {
return err
}
defer file.Close()
jsonOut, err := json.Marshal(data)
if err != nil {
return fmt.Errorf("Could not marshall data: %s", err)
}
file.Write(jsonOut)
return nil
}
func (f *filesystem) raw(id string) (string, error) {
span, _ := f.trace("raw")
defer span.Finish()
span.SetTag("id", id)
// We must use the item ID.
if id != "" {
filePath := filepath.Join(f.rawPath, id)
file, err := os.Create(filePath)
if err != nil {
return "", err
}
return filesystemScheme + "://" + file.Name(), nil
}
// Generate a random temporary file.
file, err := ioutil.TempFile(f.rawPath, "raw-")
if err != nil {
return "", err
}
defer file.Close()
return filesystemScheme + "://" + file.Name(), nil
}
func (f *filesystem) lock(item Item, exclusive bool) (string, error) {
itemPath, err := f.itemToPath(item)
if err != nil {
return "", err
}
itemFile, err := os.Open(itemPath)
if err != nil {
return "", err
}
var lockType int
if exclusive {
lockType = syscall.LOCK_EX
} else {
lockType = syscall.LOCK_SH
}
if err := syscall.Flock(int(itemFile.Fd()), lockType); err != nil {
itemFile.Close()
return "", err
}
token := uuid.Generate().String()
f.lockTokens[token] = itemFile
return token, nil
}
func (f *filesystem) unlock(item Item, token string) error {
itemFile := f.lockTokens[token]
if itemFile == nil {
return fmt.Errorf("No lock for token %s", token)
}
if err := syscall.Flock(int(itemFile.Fd()), syscall.LOCK_UN); err != nil {
return err
}
itemFile.Close()
delete(f.lockTokens, token)
return nil
}