dotcloud/docker

package plugins // import "github.com/docker/docker/pkg/plugins"

import (
    "encoding/json"
    "fmt"
    "io/fs"
    "net/url"
    "os"
    "path/filepath"
    "strings"
    "sync"

    "github.com/containerd/containerd/pkg/userns"
    "github.com/containerd/log"
    "github.com/pkg/errors"
)

// ErrNotFound plugin not found
var ErrNotFound = errors.New("plugin not found")

const defaultSocketsPath = "/run/docker/plugins"

// LocalRegistry defines a registry that is local (using unix socket).
type LocalRegistry struct {
    socketsPath string
    specsPaths  []string
}

func NewLocalRegistry() LocalRegistry {
    return LocalRegistry{
        socketsPath: defaultSocketsPath,
        specsPaths:  specsPaths(),
    }
}

// Scan scans all the plugin paths and returns all the names it found
func (l *LocalRegistry) Scan() ([]string, error) {
    var names []string
    dirEntries, err := os.ReadDir(l.socketsPath)
    if err != nil && !os.IsNotExist(err) {
        return nil, errors.Wrap(err, "error reading dir entries")
    }

    for _, entry := range dirEntries {
        if entry.IsDir() {
            fi, err := os.Stat(filepath.Join(l.socketsPath, entry.Name(), entry.Name()+".sock"))
            if err != nil {
                continue
            }

            entry = fs.FileInfoToDirEntry(fi)
        }

        if entry.Type()&os.ModeSocket != 0 {
            names = append(names, strings.TrimSuffix(filepath.Base(entry.Name()), filepath.Ext(entry.Name())))
        }
    }

    for _, p := range l.specsPaths {
        dirEntries, err = os.ReadDir(p)
        if err != nil {
            if os.IsNotExist(err) {
                continue
            }
            if os.IsPermission(err) && userns.RunningInUserNS() {
                log.L.Debug(err.Error())
                continue
            }
            return nil, errors.Wrap(err, "error reading dir entries")
        }
        for _, entry := range dirEntries {
            if entry.IsDir() {
                infos, err := os.ReadDir(filepath.Join(p, entry.Name()))
                if err != nil {
                    continue
                }

                for _, info := range infos {
                    if strings.TrimSuffix(info.Name(), filepath.Ext(info.Name())) == entry.Name() {
                        entry = info
                        break
                    }
                }
            }

            switch ext := filepath.Ext(entry.Name()); ext {
            case ".spec", ".json":
                plugin := strings.TrimSuffix(entry.Name(), ext)
                names = append(names, plugin)
            default:
            }
        }
    }
    return names, nil
}

// Plugin returns the plugin registered with the given name (or returns an error).
func (l *LocalRegistry) Plugin(name string) (*Plugin, error) {
    socketPaths := pluginPaths(l.socketsPath, name, ".sock")
    for _, p := range socketPaths {
        if fi, err := os.Stat(p); err == nil && fi.Mode()&os.ModeSocket != 0 {
            return NewLocalPlugin(name, "unix://"+p), nil
        }
    }

    var txtSpecPaths []string
    for _, p := range l.specsPaths {
        txtSpecPaths = append(txtSpecPaths, pluginPaths(p, name, ".spec")...)
        txtSpecPaths = append(txtSpecPaths, pluginPaths(p, name, ".json")...)
    }

    for _, p := range txtSpecPaths {
        if _, err := os.Stat(p); err == nil {
            if strings.HasSuffix(p, ".json") {
                return readPluginJSONInfo(name, p)
            }
            return readPluginInfo(name, p)
        }
    }
    return nil, errors.Wrapf(ErrNotFound, "could not find plugin %s in v1 plugin registry", name)
}

// SpecsPaths returns paths in which to look for plugins, in order of priority.
//
// On Windows:
//
//   - "%programdata%\docker\plugins"
//
// On Unix in non-rootless mode:
//
//   - "/etc/docker/plugins"
//   - "/usr/lib/docker/plugins"
//
// On Unix in rootless-mode:
//
//   - "$XDG_CONFIG_HOME/docker/plugins" (or "/etc/docker/plugins" if $XDG_CONFIG_HOME is not set)
//   - "$HOME/.local/lib/docker/plugins" (pr "/usr/lib/docker/plugins" if $HOME is set)
func SpecsPaths() []string {
    return specsPaths()
}

func readPluginInfo(name, path string) (*Plugin, error) {
    content, err := os.ReadFile(path)
    if err != nil {
        return nil, err
    }
    addr := strings.TrimSpace(string(content))

    u, err := url.Parse(addr)
    if err != nil {
        return nil, err
    }

    if len(u.Scheme) == 0 {
        return nil, fmt.Errorf("Unknown protocol")
    }

    return NewLocalPlugin(name, addr), nil
}

func readPluginJSONInfo(name, path string) (*Plugin, error) {
    f, err := os.Open(path)
    if err != nil {
        return nil, err
    }
    defer f.Close()

    var p Plugin
    if err := json.NewDecoder(f).Decode(&p); err != nil {
        return nil, err
    }
    p.name = name
    if p.TLSConfig != nil && len(p.TLSConfig.CAFile) == 0 {
        p.TLSConfig.InsecureSkipVerify = true
    }
    p.activateWait = sync.NewCond(&sync.Mutex{})

    return &p, nil
}

func pluginPaths(base, name, ext string) []string {
    return []string{
        filepath.Join(base, name+ext),
        filepath.Join(base, name, name+ext),
    }
}