ext: data detector -> imagefmt

cmd/clair/main.go

@@ -1,4 +1,4 @@
-// Copyright 2015 clair authors
+// Copyright 2017 clair authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -26,6 +26,8 @@ import (
 	"github.com/coreos/clair/config"
 
 	// Register extensions.
+	_ "github.com/coreos/clair/ext/imagefmt/aci"
+	_ "github.com/coreos/clair/ext/imagefmt/docker"
 	_ "github.com/coreos/clair/ext/notification/webhook"
 	_ "github.com/coreos/clair/ext/vulnmdsrc/nvd"
 	_ "github.com/coreos/clair/ext/vulnsrc/alpine"
@@ -34,9 +36,6 @@ import (
 	_ "github.com/coreos/clair/ext/vulnsrc/rhel"
 	_ "github.com/coreos/clair/ext/vulnsrc/ubuntu"
 
-	_ "github.com/coreos/clair/worker/detectors/data/aci"
-	_ "github.com/coreos/clair/worker/detectors/data/docker"
-
 	_ "github.com/coreos/clair/worker/detectors/feature/apk"
 	_ "github.com/coreos/clair/worker/detectors/feature/dpkg"
 	_ "github.com/coreos/clair/worker/detectors/feature/rpm"

ext/imagefmt/aci/aci.go

@@ -0,0 +1,40 @@
+// Copyright 2017 clair authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package aci
+
+import (
+	"io"
+	"path/filepath"
+
+	"github.com/coreos/clair/ext/imagefmt"
+	"github.com/coreos/clair/pkg/tarutil"
+)
+
+type format struct{}
+
+func init() {
+	imagefmt.RegisterExtractor("aci", &format{})
+}
+
+func (f format) ExtractFiles(layerReader io.ReadCloser, toExtract []string) (tarutil.FilesMap, error) {
+	// All contents are inside a "rootfs" directory, so this needs to be
+	// prepended to each filename.
+	var filenames []string
+	for _, filename := range toExtract {
+		filenames = append(filenames, filepath.Join("rootfs/", filename))
+	}
+
+	return tarutil.ExtractFiles(layerReader, filenames)
+}

ext/imagefmt/docker/docker.go

@@ -0,0 +1,32 @@
+// Copyright 2017 clair authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package docker
+
+import (
+	"io"
+
+	"github.com/coreos/clair/ext/imagefmt"
+	"github.com/coreos/clair/pkg/tarutil"
+)
+
+type format struct{}
+
+func init() {
+	imagefmt.RegisterExtractor("docker", &format{})
+}
+
+func (f format) ExtractFiles(layerReader io.ReadCloser, toExtract []string) (tarutil.FilesMap, error) {
+	return tarutil.ExtractFiles(layerReader, toExtract)
+}

ext/imagefmt/driver.go

@@ -0,0 +1,150 @@
+// Copyright 2017 clair authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package notification fetches notifications from the database and informs the
+// specified remote handler about their existences, inviting the third party to
+// actively query the API about it.
+
+// Package imagefmt exposes functions to dynamically register methods to
+// detect different types of container image formats.
+package imagefmt
+
+import (
+	"fmt"
+	"io"
+	"math"
+	"net/http"
+	"os"
+	"strings"
+	"sync"
+
+	"github.com/coreos/clair/pkg/commonerr"
+	"github.com/coreos/clair/pkg/tarutil"
+	"github.com/coreos/pkg/capnslog"
+)
+
+var (
+	// ErrCouldNotFindLayer is returned when we could not download or open the layer file.
+	ErrCouldNotFindLayer = commonerr.NewBadRequestError("could not find layer")
+
+	log = capnslog.NewPackageLogger("github.com/coreos/clair", "ext/imagefmt")
+
+	extractorsM sync.RWMutex
+	extractors  = make(map[string]Extractor)
+)
+
+// Extractor represents an ability to extract files from a particular container
+// image format.
+type Extractor interface {
+	// ExtractFiles produces a tarutil.FilesMap from a image layer.
+	ExtractFiles(layer io.ReadCloser, filenames []string) (tarutil.FilesMap, error)
+}
+
+// RegisterExtractor makes a extractor available by the provided name.
+//
+// If called twice with the same name, the name is blank, or if the provided
+// Extractor is nil, this function panics.
+func RegisterExtractor(name string, d Extractor) {
+	extractorsM.Lock()
+	defer extractorsM.Unlock()
+
+	if name == "" {
+		panic("imagefmt: could not register a extractor with an empty name")
+	}
+
+	if d == nil {
+		panic("imagefmt: could not register a nil extractor")
+	}
+
+	// Enforce lowercase names, so that they can be reliably be found in a map.
+	name = strings.ToLower(name)
+
+	if _, dup := extractors[name]; dup {
+		panic("imagefmt: RegisterExtractor called twice for " + name)
+	}
+
+	extractors[name] = d
+}
+
+// Extractors returns the list of the registered extractors.
+func Extractors() map[string]Extractor {
+	extractorsM.RLock()
+	defer extractorsM.RUnlock()
+
+	ret := make(map[string]Extractor)
+	for k, v := range extractors {
+		ret[k] = v
+	}
+
+	return ret
+}
+
+// UnregisterExtractor removes a Extractor with a particular name from the list.
+func UnregisterExtractor(name string) {
+	extractorsM.Lock()
+	defer extractorsM.Unlock()
+	delete(extractors, name)
+}
+
+// Extract streams an image layer from disk or over HTTP, determines the
+// image format, then extracts the files specified.
+func Extract(format, path string, headers map[string]string, toExtract []string) (tarutil.FilesMap, error) {
+	var layerReader io.ReadCloser
+	if strings.HasPrefix(path, "http://") || strings.HasPrefix(path, "https://") {
+		// Create a new HTTP request object.
+		request, err := http.NewRequest("GET", path, nil)
+		if err != nil {
+			return nil, ErrCouldNotFindLayer
+		}
+
+		// Set any provided HTTP Headers.
+		if headers != nil {
+			for k, v := range headers {
+				request.Header.Set(k, v)
+			}
+		}
+
+		// Send the request and handle the response.
+		r, err := http.DefaultClient.Do(request)
+		if err != nil {
+			log.Warningf("could not download layer: %s", err)
+			return nil, ErrCouldNotFindLayer
+		}
+
+		// Fail if we don't receive a 2xx HTTP status code.
+		if math.Floor(float64(r.StatusCode/100)) != 2 {
+			log.Warningf("could not download layer: got status code %d, expected 2XX", r.StatusCode)
+			return nil, ErrCouldNotFindLayer
+		}
+
+		layerReader = r.Body
+	} else {
+		var err error
+		layerReader, err = os.Open(path)
+		if err != nil {
+			return nil, ErrCouldNotFindLayer
+		}
+	}
+	defer layerReader.Close()
+
+	if extractor, exists := Extractors()[strings.ToLower(format)]; exists {
+		files, err := extractor.ExtractFiles(layerReader, toExtract)
+		if err != nil {
+			return nil, err
+		}
+		return files, nil
+	}
+
+	return nil, commonerr.NewBadRequestError(fmt.Sprintf("unsupported image format '%s'", format))
+}