fs: Cleanup Golang errors to be called 'e' and probe to be called as 'err'

- Replace the ACL checks back, remove them when bucket
  policy is implemented.
- Move FTW (File Tree Walk) into ioutils package.

accesslog-handler.go

@@ -59,10 +59,10 @@ type LogMessage struct {
 }
 
 func (h *accessLogHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
-	message, perr := getLogMessage(w, req)
-	fatalIf(perr.Trace(), "Unable to extract http message.", nil)
-	_, err := h.accessLogFile.Write(message)
-	fatalIf(probe.NewError(err), "Writing to log file failed.", nil)
+	message, err := getLogMessage(w, req)
+	fatalIf(err.Trace(), "Unable to extract http message.", nil)
+	_, e := h.accessLogFile.Write(message)
+	fatalIf(probe.NewError(e), "Writing to log file failed.", nil)
 
 	h.Handler.ServeHTTP(w, req)
 }
@@ -103,9 +103,9 @@ func getLogMessage(w http.ResponseWriter, req *http.Request) ([]byte, *probe.Err
 
 	// logMessage.HTTP.Request = req
 	logMessage.Duration = time.Now().UTC().Sub(logMessage.StartTime)
-	js, err := json.Marshal(logMessage)
-	if err != nil {
-		return nil, probe.NewError(err)
+	js, e := json.Marshal(logMessage)
+	if e != nil {
+		return nil, probe.NewError(e)
 	}
 	js = append(js, byte('\n')) // append a new line
 	return js, nil
@@ -113,8 +113,8 @@ func getLogMessage(w http.ResponseWriter, req *http.Request) ([]byte, *probe.Err
 
 // AccessLogHandler logs requests
 func AccessLogHandler(h http.Handler) http.Handler {
-	file, err := os.OpenFile("access.log", os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0600)
-	fatalIf(probe.NewError(err), "Unable to open access log.", nil)
+	file, e := os.OpenFile("access.log", os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0600)
+	fatalIf(probe.NewError(e), "Unable to open access log.", nil)
 
 	return &accessLogHandler{Handler: h, accessLogFile: file}
 }

api-auth-utils.go

@@ -42,9 +42,8 @@ func isValidAccessKey(accessKeyID string) bool {
 // takes input as size in integer
 func generateAccessKeyID() ([]byte, *probe.Error) {
 	alpha := make([]byte, minioAccessID)
-	_, err := rand.Read(alpha)
-	if err != nil {
-		return nil, probe.NewError(err)
+	if _, e := rand.Read(alpha); e != nil {
+		return nil, probe.NewError(e)
 	}
 	for i := 0; i < minioAccessID; i++ {
 		alpha[i] = alphaNumericTable[alpha[i]%byte(len(alphaNumericTable))]
@@ -55,9 +54,8 @@ func generateAccessKeyID() ([]byte, *probe.Error) {
 // generateSecretAccessKey - generate random base64 numeric value from a random seed.
 func generateSecretAccessKey() ([]byte, *probe.Error) {
 	rb := make([]byte, minioSecretID)
-	_, err := rand.Read(rb)
-	if err != nil {
-		return nil, probe.NewError(err)
+	if _, e := rand.Read(rb); e != nil {
+		return nil, probe.NewError(e)
 	}
 	return []byte(base64.StdEncoding.EncodeToString(rb))[:minioSecretID], nil
 }

api-signature.go

@@ -173,21 +173,20 @@ func extractHTTPFormValues(reader *multipart.Reader) (io.Reader, map[string]stri
 	/// HTML Form values
 	formValues := make(map[string]string)
 	filePart := new(bytes.Buffer)
-	var err error
-	for err == nil {
+	var e error
+	for e == nil {
 		var part *multipart.Part
-		part, err = reader.NextPart()
+		part, e = reader.NextPart()
 		if part != nil {
 			if part.FileName() == "" {
-				buffer, err := ioutil.ReadAll(part)
-				if err != nil {
-					return nil, nil, probe.NewError(err)
+				buffer, e := ioutil.ReadAll(part)
+				if e != nil {
+					return nil, nil, probe.NewError(e)
 				}
 				formValues[http.CanonicalHeaderKey(part.FormName())] = string(buffer)
 			} else {
-				_, err := io.Copy(filePart, part)
-				if err != nil {
-					return nil, nil, probe.NewError(err)
+				if _, e := io.Copy(filePart, part); e != nil {
+					return nil, nil, probe.NewError(e)
 				}
 			}
 		}
@@ -200,13 +199,13 @@ func applyPolicy(formValues map[string]string) *probe.Error {
 		return probe.NewError(errUnsupportedAlgorithm)
 	}
 	/// Decoding policy
-	policyBytes, err := base64.StdEncoding.DecodeString(formValues["Policy"])
-	if err != nil {
-		return probe.NewError(err)
+	policyBytes, e := base64.StdEncoding.DecodeString(formValues["Policy"])
+	if e != nil {
+		return probe.NewError(e)
 	}
-	postPolicyForm, perr := fs.ParsePostPolicyForm(string(policyBytes))
-	if perr != nil {
-		return perr.Trace()
+	postPolicyForm, err := fs.ParsePostPolicyForm(string(policyBytes))
+	if err != nil {
+		return err.Trace()
 	}
 	if !postPolicyForm.Expiration.After(time.Now().UTC()) {
 		return probe.NewError(errPolicyAlreadyExpired)
@@ -254,9 +253,9 @@ func initPostPresignedPolicyV4(formValues map[string]string) (*fs.Signature, *pr
 	if !isValidAccessKey(accessKeyID) {
 		return nil, probe.NewError(errAccessKeyIDInvalid)
 	}
-	config, perr := loadConfigV2()
-	if perr != nil {
-		return nil, perr.Trace()
+	config, err := loadConfigV2()
+	if err != nil {
+		return nil, err.Trace()
 	}
 	region := credentialElements[2]
 	if config.Credentials.AccessKeyID == accessKeyID {

bucket-handlers.go

@@ -34,6 +34,11 @@ func (api CloudStorageAPI) GetBucketLocationHandler(w http.ResponseWriter, req *
 	vars := mux.Vars(req)
 	bucket := vars["bucket"]
 
+	if isRequestRequiresACLCheck(req) {
+		writeErrorResponse(w, req, AccessDenied, req.URL.Path)
+		return
+	}
+
 	_, err := api.Filesystem.GetBucketMetadata(bucket)
 	if err != nil {
 		errorIf(err.Trace(), "GetBucketMetadata failed.", nil)
@@ -68,6 +73,11 @@ func (api CloudStorageAPI) ListMultipartUploadsHandler(w http.ResponseWriter, re
 	vars := mux.Vars(req)
 	bucket := vars["bucket"]
 
+	if isRequestRequiresACLCheck(req) {
+		writeErrorResponse(w, req, AccessDenied, req.URL.Path)
+		return
+	}
+
 	resources := getBucketMultipartResources(req.URL.Query())
 	if resources.MaxUploads < 0 {
 		writeErrorResponse(w, req, InvalidMaxUploads, req.URL.Path)
@@ -107,6 +117,13 @@ func (api CloudStorageAPI) ListObjectsHandler(w http.ResponseWriter, req *http.R
 	vars := mux.Vars(req)
 	bucket := vars["bucket"]
 
+	if isRequestRequiresACLCheck(req) {
+		if api.Filesystem.IsPrivateBucket(bucket) {
+			writeErrorResponse(w, req, AccessDenied, req.URL.Path)
+			return
+		}
+	}
+
 	// TODO handle encoding type.
 	prefix, marker, delimiter, maxkeys, _ := getBucketResources(req.URL.Query())
 	if maxkeys < 0 {
@@ -148,6 +165,11 @@ func (api CloudStorageAPI) ListObjectsHandler(w http.ResponseWriter, req *http.R
 // This implementation of the GET operation returns a list of all buckets
 // owned by the authenticated sender of the request.
 func (api CloudStorageAPI) ListBucketsHandler(w http.ResponseWriter, req *http.Request) {
+	if isRequestRequiresACLCheck(req) {
+		writeErrorResponse(w, req, AccessDenied, req.URL.Path)
+		return
+	}
+
 	buckets, err := api.Filesystem.ListBuckets()
 	if err == nil {
 		// generate response
@@ -170,6 +192,11 @@ func (api CloudStorageAPI) PutBucketHandler(w http.ResponseWriter, req *http.Req
 	vars := mux.Vars(req)
 	bucket := vars["bucket"]
 
+	if isRequestRequiresACLCheck(req) {
+		writeErrorResponse(w, req, AccessDenied, req.URL.Path)
+		return
+	}
+
 	// read from 'x-amz-acl'
 	aclType := getACLType(req)
 	if aclType == unsupportedACLType {
@@ -208,20 +235,23 @@ func (api CloudStorageAPI) PutBucketHandler(w http.ResponseWriter, req *http.Req
 			return
 		}
 		if signature != nil {
-			locationBytes, err := ioutil.ReadAll(req.Body)
+			locationBytes, e := ioutil.ReadAll(req.Body)
+			if e != nil {
+				errorIf(probe.NewError(e), "MakeBucket failed.", nil)
+				writeErrorResponse(w, req, InternalError, req.URL.Path)
+				return
+			}
+			sh := sha256.New()
+			sh.Write(locationBytes)
+			ok, err := signature.DoesSignatureMatch(hex.EncodeToString(sh.Sum(nil)))
 			if err != nil {
-				sh := sha256.New()
-				sh.Write(locationBytes)
-				ok, perr := signature.DoesSignatureMatch(hex.EncodeToString(sh.Sum(nil)))
-				if perr != nil {
-					errorIf(perr.Trace(), "MakeBucket failed.", nil)
-					writeErrorResponse(w, req, InternalError, req.URL.Path)
-					return
-				}
-				if !ok {
-					writeErrorResponse(w, req, SignatureDoesNotMatch, req.URL.Path)
-					return
-				}
+				errorIf(err.Trace(), "MakeBucket failed.", nil)
+				writeErrorResponse(w, req, InternalError, req.URL.Path)
+				return
+			}
+			if !ok {
+				writeErrorResponse(w, req, SignatureDoesNotMatch, req.URL.Path)
+				return
 			}
 		}
 	}
@@ -261,31 +291,31 @@ func (api CloudStorageAPI) PostPolicyBucketHandler(w http.ResponseWriter, req *h
 	// Here the parameter is the size of the form data that should
 	// be loaded in memory, the remaining being put in temporary
 	// files
-	reader, err := req.MultipartReader()
-	if err != nil {
-		errorIf(probe.NewError(err), "Unable to initialize multipart reader.", nil)
+	reader, e := req.MultipartReader()
+	if e != nil {
+		errorIf(probe.NewError(e), "Unable to initialize multipart reader.", nil)
 		writeErrorResponse(w, req, MalformedPOSTRequest, req.URL.Path)
 		return
 	}
 
-	fileBody, formValues, perr := extractHTTPFormValues(reader)
-	if perr != nil {
-		errorIf(perr.Trace(), "Unable to parse form values.", nil)
+	fileBody, formValues, err := extractHTTPFormValues(reader)
+	if err != nil {
+		errorIf(err.Trace(), "Unable to parse form values.", nil)
 		writeErrorResponse(w, req, MalformedPOSTRequest, req.URL.Path)
 		return
 	}
 	bucket := mux.Vars(req)["bucket"]
 	formValues["Bucket"] = bucket
 	object := formValues["Key"]
-	signature, perr := initPostPresignedPolicyV4(formValues)
-	if perr != nil {
-		errorIf(perr.Trace(), "Unable to initialize post policy presigned.", nil)
+	signature, err := initPostPresignedPolicyV4(formValues)
+	if err != nil {
+		errorIf(err.Trace(), "Unable to initialize post policy presigned.", nil)
 		writeErrorResponse(w, req, MalformedPOSTRequest, req.URL.Path)
 		return
 	}
 	var ok bool
-	if ok, perr = signature.DoesPolicySignatureMatch(formValues["X-Amz-Date"]); perr != nil {
-		errorIf(perr.Trace(), "Unable to verify signature.", nil)
+	if ok, err = signature.DoesPolicySignatureMatch(formValues["X-Amz-Date"]); err != nil {
+		errorIf(err.Trace(), "Unable to verify signature.", nil)
 		writeErrorResponse(w, req, SignatureDoesNotMatch, req.URL.Path)
 		return
 	}
@@ -293,15 +323,15 @@ func (api CloudStorageAPI) PostPolicyBucketHandler(w http.ResponseWriter, req *h
 		writeErrorResponse(w, req, SignatureDoesNotMatch, req.URL.Path)
 		return
 	}
-	if perr = applyPolicy(formValues); perr != nil {
-		errorIf(perr.Trace(), "Invalid request, policy doesn't match with the endpoint.", nil)
+	if err = applyPolicy(formValues); err != nil {
+		errorIf(err.Trace(), "Invalid request, policy doesn't match with the endpoint.", nil)
 		writeErrorResponse(w, req, MalformedPOSTRequest, req.URL.Path)
 		return
 	}
-	metadata, perr := api.Filesystem.CreateObject(bucket, object, "", 0, fileBody, nil)
-	if perr != nil {
-		errorIf(perr.Trace(), "CreateObject failed.", nil)
-		switch perr.ToGoError().(type) {
+	metadata, err := api.Filesystem.CreateObject(bucket, object, "", 0, fileBody, nil)
+	if err != nil {
+		errorIf(err.Trace(), "CreateObject failed.", nil)
+		switch err.ToGoError().(type) {
 		case fs.RootPathFull:
 			writeErrorResponse(w, req, RootPathFull, req.URL.Path)
 		case fs.BucketNotFound:
@@ -336,6 +366,11 @@ func (api CloudStorageAPI) PutBucketACLHandler(w http.ResponseWriter, req *http.
 	vars := mux.Vars(req)
 	bucket := vars["bucket"]
 
+	if isRequestRequiresACLCheck(req) {
+		writeErrorResponse(w, req, AccessDenied, req.URL.Path)
+		return
+	}
+
 	// read from 'x-amz-acl'
 	aclType := getACLType(req)
 	if aclType == unsupportedACLType {
@@ -368,6 +403,11 @@ func (api CloudStorageAPI) GetBucketACLHandler(w http.ResponseWriter, req *http.
 	vars := mux.Vars(req)
 	bucket := vars["bucket"]
 
+	if isRequestRequiresACLCheck(req) {
+		writeErrorResponse(w, req, AccessDenied, req.URL.Path)
+		return
+	}
+
 	bucketMetadata, err := api.Filesystem.GetBucketMetadata(bucket)
 	if err != nil {
 		errorIf(err.Trace(), "GetBucketMetadata failed.", nil)
@@ -400,6 +440,13 @@ func (api CloudStorageAPI) HeadBucketHandler(w http.ResponseWriter, req *http.Re
 	vars := mux.Vars(req)
 	bucket := vars["bucket"]
 
+	if isRequestRequiresACLCheck(req) {
+		if api.Filesystem.IsPrivateBucket(bucket) {
+			writeErrorResponse(w, req, AccessDenied, req.URL.Path)
+			return
+		}
+	}
+
 	_, err := api.Filesystem.GetBucketMetadata(bucket)
 	if err != nil {
 		errorIf(err.Trace(), "GetBucketMetadata failed.", nil)
@@ -421,6 +468,11 @@ func (api CloudStorageAPI) DeleteBucketHandler(w http.ResponseWriter, req *http.
 	vars := mux.Vars(req)
 	bucket := vars["bucket"]
 
+	if isRequestRequiresACLCheck(req) {
+		writeErrorResponse(w, req, AccessDenied, req.URL.Path)
+		return
+	}
+
 	err := api.Filesystem.DeleteBucket(bucket)
 	if err != nil {
 		errorIf(err.Trace(), "DeleteBucket failed.", nil)

main.go

@@ -19,7 +19,6 @@ package main
 import (
 	"fmt"
 	"os"
-	"os/user"
 	"runtime"
 	"strconv"
 
@@ -55,12 +54,6 @@ func init() {
 	// Check if minio was compiled using a supported version of Golang.
 	checkGolangRuntimeVersion()
 
-	// Check for the environment early on and gracefuly report.
-	_, err := user.Current()
-	if err != nil {
-
-	}
-
 	if os.Getenv("DOCKERIMAGE") == "1" {
 		// the further checks are ignored for docker image
 		return

object-handlers.go

@@ -39,6 +39,13 @@ func (api CloudStorageAPI) GetObjectHandler(w http.ResponseWriter, req *http.Req
 	bucket = vars["bucket"]
 	object = vars["object"]
 
+	if isRequestRequiresACLCheck(req) {
+		if api.Filesystem.IsPrivateBucket(bucket) {
+			writeErrorResponse(w, req, AccessDenied, req.URL.Path)
+			return
+		}
+	}
+
 	metadata, err := api.Filesystem.GetObjectMetadata(bucket, object)
 	if err != nil {
 		errorIf(err.Trace(), "GetObject failed.", nil)
@@ -78,6 +85,13 @@ func (api CloudStorageAPI) HeadObjectHandler(w http.ResponseWriter, req *http.Re
 	bucket = vars["bucket"]
 	object = vars["object"]
 
+	if isRequestRequiresACLCheck(req) {
+		if api.Filesystem.IsPrivateBucket(bucket) {
+			writeErrorResponse(w, req, AccessDenied, req.URL.Path)
+			return
+		}
+	}
+
 	metadata, err := api.Filesystem.GetObjectMetadata(bucket, object)
 	if err != nil {
 		switch err.ToGoError().(type) {
@@ -107,6 +121,13 @@ func (api CloudStorageAPI) PutObjectHandler(w http.ResponseWriter, req *http.Req
 	bucket = vars["bucket"]
 	object = vars["object"]
 
+	if isRequestRequiresACLCheck(req) {
+		if api.Filesystem.IsPrivateBucket(bucket) || api.Filesystem.IsReadOnlyBucket(bucket) {
+			writeErrorResponse(w, req, AccessDenied, req.URL.Path)
+			return
+		}
+	}
+
 	// get Content-MD5 sent by client and verify if valid
 	md5 := req.Header.Get("Content-MD5")
 	if !isValidMD5(md5) {
@@ -192,6 +213,13 @@ func (api CloudStorageAPI) NewMultipartUploadHandler(w http.ResponseWriter, req
 	bucket = vars["bucket"]
 	object = vars["object"]
 
+	if isRequestRequiresACLCheck(req) {
+		if api.Filesystem.IsPrivateBucket(bucket) || api.Filesystem.IsReadOnlyBucket(bucket) {
+			writeErrorResponse(w, req, AccessDenied, req.URL.Path)
+			return
+		}
+	}
+
 	uploadID, err := api.Filesystem.NewMultipartUpload(bucket, object)
 	if err != nil {
 		errorIf(err.Trace(), "NewMultipartUpload failed.", nil)
@@ -226,6 +254,13 @@ func (api CloudStorageAPI) PutObjectPartHandler(w http.ResponseWriter, req *http
 	bucket := vars["bucket"]
 	object := vars["object"]
 
+	if isRequestRequiresACLCheck(req) {
+		if api.Filesystem.IsPrivateBucket(bucket) || api.Filesystem.IsReadOnlyBucket(bucket) {
+			writeErrorResponse(w, req, AccessDenied, req.URL.Path)
+			return
+		}
+	}
+
 	// get Content-MD5 sent by client and verify if valid
 	md5 := req.Header.Get("Content-MD5")
 	if !isValidMD5(md5) {
@@ -317,6 +352,13 @@ func (api CloudStorageAPI) AbortMultipartUploadHandler(w http.ResponseWriter, re
 	bucket := vars["bucket"]
 	object := vars["object"]
 
+	if isRequestRequiresACLCheck(req) {
+		if api.Filesystem.IsPrivateBucket(bucket) || api.Filesystem.IsReadOnlyBucket(bucket) {
+			writeErrorResponse(w, req, AccessDenied, req.URL.Path)
+			return
+		}
+	}
+
 	objectResourcesMetadata := getObjectResources(req.URL.Query())
 	err := api.Filesystem.AbortMultipartUpload(bucket, object, objectResourcesMetadata.UploadID)
 	if err != nil {
@@ -346,6 +388,13 @@ func (api CloudStorageAPI) ListObjectPartsHandler(w http.ResponseWriter, req *ht
 	bucket := vars["bucket"]
 	object := vars["object"]
 
+	if isRequestRequiresACLCheck(req) {
+		if api.Filesystem.IsPrivateBucket(bucket) || api.Filesystem.IsReadOnlyBucket(bucket) {
+			writeErrorResponse(w, req, AccessDenied, req.URL.Path)
+			return
+		}
+	}
+
 	objectResourcesMetadata := getObjectResources(req.URL.Query())
 	if objectResourcesMetadata.PartNumberMarker < 0 {
 		writeErrorResponse(w, req, InvalidPartNumberMarker, req.URL.Path)
@@ -392,6 +441,13 @@ func (api CloudStorageAPI) CompleteMultipartUploadHandler(w http.ResponseWriter,
 	bucket := vars["bucket"]
 	object := vars["object"]
 
+	if isRequestRequiresACLCheck(req) {
+		if api.Filesystem.IsPrivateBucket(bucket) || api.Filesystem.IsReadOnlyBucket(bucket) {
+			writeErrorResponse(w, req, AccessDenied, req.URL.Path)
+			return
+		}
+	}
+
 	objectResourcesMetadata := getObjectResources(req.URL.Query())
 	var signature *fs.Signature
 	if isRequestSignatureV4(req) {
@@ -461,6 +517,13 @@ func (api CloudStorageAPI) DeleteObjectHandler(w http.ResponseWriter, req *http.
 	bucket := vars["bucket"]
 	object := vars["object"]
 
+	if isRequestRequiresACLCheck(req) {
+		if api.Filesystem.IsPrivateBucket(bucket) || api.Filesystem.IsReadOnlyBucket(bucket) {
+			writeErrorResponse(w, req, AccessDenied, req.URL.Path)
+			return
+		}
+	}
+
 	err := api.Filesystem.DeleteObject(bucket, object)
 	if err != nil {
 		errorIf(err.Trace(), "DeleteObject failed.", nil)

pkg/fs/fs-bucket-listobjects.go

@@ -26,6 +26,7 @@ import (
 	"time"
 
 	"github.com/minio/minio-xl/pkg/probe"
+	"github.com/minio/minio/pkg/ioutils"
 )
 
 // listObjectsParams - list objects input parameters.
@@ -77,7 +78,7 @@ func (fs Filesystem) listObjects(bucket, prefix, marker, delimiter string, maxKe
 				walkPath = prefixPath
 			}
 		}
-		Walk(walkPath, func(path string, info os.FileInfo, err error) error {
+		ioutils.FTW(walkPath, func(path string, info os.FileInfo, err error) error {
 			// We don't need to list the walk path.
 			if path == walkPath {
 				return nil
@@ -108,7 +109,7 @@ func (fs Filesystem) listObjects(bucket, prefix, marker, delimiter string, maxKe
 				// If delimiter is set, we stop if current path is a
 				// directory.
 				if delimiter != "" && info.IsDir() {
-					return ErrSkipDir
+					return ioutils.ErrSkipDir
 				}
 			}
 			return nil

pkg/fs/fs-multipart.go

@@ -273,31 +273,30 @@ func (fs Filesystem) CreateObjectPart(bucket, object, uploadID, expectedMD5Sum s
 
 	objectPath := filepath.Join(bucketPath, object)
 	partPath := objectPath + fmt.Sprintf("$%d-$multiparts", partID)
-	partFile, err := atomic.FileCreateWithPrefix(partPath, "$multiparts")
-	if err != nil {
-		return "", probe.NewError(err)
+	partFile, e := atomic.FileCreateWithPrefix(partPath, "$multiparts")
+	if e != nil {
+		return "", probe.NewError(e)
 	}
 	h := md5.New()
 	sh := sha256.New()
 	mw := io.MultiWriter(partFile, h, sh)
-	_, err = io.CopyN(mw, data, size)
-	if err != nil {
+	if _, e = io.CopyN(mw, data, size); e != nil {
 		partFile.CloseAndPurge()
-		return "", probe.NewError(err)
+		return "", probe.NewError(e)
 	}
 	md5sum := hex.EncodeToString(h.Sum(nil))
 	// Verify if the written object is equal to what is expected, only if it is requested as such
 	if strings.TrimSpace(expectedMD5Sum) != "" {
-		if err := isMD5SumEqual(strings.TrimSpace(expectedMD5Sum), md5sum); err != nil {
+		if !isMD5SumEqual(strings.TrimSpace(expectedMD5Sum), md5sum) {
 			partFile.CloseAndPurge()
 			return "", probe.NewError(BadDigest{Md5: expectedMD5Sum, Bucket: bucket, Object: object})
 		}
 	}
 	if signature != nil {
-		ok, perr := signature.DoesSignatureMatch(hex.EncodeToString(sh.Sum(nil)))
-		if perr != nil {
+		ok, err := signature.DoesSignatureMatch(hex.EncodeToString(sh.Sum(nil)))
+		if err != nil {
 			partFile.CloseAndPurge()
-			return "", perr.Trace()
+			return "", err.Trace()
 		}
 		if !ok {
 			partFile.CloseAndPurge()
@@ -306,9 +305,9 @@ func (fs Filesystem) CreateObjectPart(bucket, object, uploadID, expectedMD5Sum s
 	}
 	partFile.Close()
 
-	fi, err := os.Stat(partPath)
-	if err != nil {
-		return "", probe.NewError(err)
+	fi, e := os.Stat(partPath)
+	if e != nil {
+		return "", probe.NewError(e)
 	}
 	partMetadata := PartMetadata{}
 	partMetadata.ETag = md5sum
@@ -316,17 +315,16 @@ func (fs Filesystem) CreateObjectPart(bucket, object, uploadID, expectedMD5Sum s
 	partMetadata.Size = fi.Size()
 	partMetadata.LastModified = fi.ModTime()
 
-	multiPartfile, err := os.OpenFile(objectPath+"$multiparts", os.O_RDWR|os.O_APPEND, 0600)
-	if err != nil {
-		return "", probe.NewError(err)
+	multiPartfile, e := os.OpenFile(objectPath+"$multiparts", os.O_RDWR|os.O_APPEND, 0600)
+	if e != nil {
+		return "", probe.NewError(e)
 	}
 	defer multiPartfile.Close()
 
 	var deserializedMultipartSession MultipartSession
 	decoder := json.NewDecoder(multiPartfile)
-	err = decoder.Decode(&deserializedMultipartSession)
-	if err != nil {
-		return "", probe.NewError(err)
+	if e = decoder.Decode(&deserializedMultipartSession); e != nil {
+		return "", probe.NewError(e)
 	}
 	deserializedMultipartSession.Parts = append(deserializedMultipartSession.Parts, &partMetadata)
 	deserializedMultipartSession.TotalParts++
@@ -334,9 +332,8 @@ func (fs Filesystem) CreateObjectPart(bucket, object, uploadID, expectedMD5Sum s
 
 	sort.Sort(partNumber(deserializedMultipartSession.Parts))
 	encoder := json.NewEncoder(multiPartfile)
-	err = encoder.Encode(&deserializedMultipartSession)
-	if err != nil {
-		return "", probe.NewError(err)
+	if e = encoder.Encode(&deserializedMultipartSession); e != nil {
+		return "", probe.NewError(e)
 	}
 	return partMetadata.ETag, nil
 }
@@ -362,34 +359,34 @@ func (fs Filesystem) CompleteMultipartUpload(bucket, object, uploadID string, da
 
 	bucket = fs.denormalizeBucket(bucket)
 	bucketPath := filepath.Join(fs.path, bucket)
-	if _, err := os.Stat(bucketPath); err != nil {
+	if _, e := os.Stat(bucketPath); e != nil {
 		// check bucket exists
-		if os.IsNotExist(err) {
+		if os.IsNotExist(e) {
 			return ObjectMetadata{}, probe.NewError(BucketNotFound{Bucket: bucket})
 		}
 		return ObjectMetadata{}, probe.NewError(InternalError{})
 	}
 
 	objectPath := filepath.Join(bucketPath, object)
-	file, err := atomic.FileCreateWithPrefix(objectPath, "")
-	if err != nil {
-		return ObjectMetadata{}, probe.NewError(err)
+	file, e := atomic.FileCreateWithPrefix(objectPath, "")
+	if e != nil {
+		return ObjectMetadata{}, probe.NewError(e)
 	}
 	h := md5.New()
 	mw := io.MultiWriter(file, h)
 
-	partBytes, err := ioutil.ReadAll(data)
-	if err != nil {
+	partBytes, e := ioutil.ReadAll(data)
+	if e != nil {
 		file.CloseAndPurge()
-		return ObjectMetadata{}, probe.NewError(err)
+		return ObjectMetadata{}, probe.NewError(e)
 	}
 	if signature != nil {
 		sh := sha256.New()
 		sh.Write(partBytes)
-		ok, perr := signature.DoesSignatureMatch(hex.EncodeToString(sh.Sum(nil)))
-		if perr != nil {
+		ok, err := signature.DoesSignatureMatch(hex.EncodeToString(sh.Sum(nil)))
+		if err != nil {
 			file.CloseAndPurge()
-			return ObjectMetadata{}, probe.NewError(err)
+			return ObjectMetadata{}, err.Trace()
 		}
 		if !ok {
 			file.CloseAndPurge()
@@ -397,7 +394,7 @@ func (fs Filesystem) CompleteMultipartUpload(bucket, object, uploadID string, da
 		}
 	}
 	parts := &CompleteMultipartUpload{}
-	if err := xml.Unmarshal(partBytes, parts); err != nil {
+	if e := xml.Unmarshal(partBytes, parts); e != nil {
 		file.CloseAndPurge()
 		return ObjectMetadata{}, probe.NewError(MalformedXML{})
 	}
@@ -413,25 +410,24 @@ func (fs Filesystem) CompleteMultipartUpload(bucket, object, uploadID string, da
 
 	delete(fs.multiparts.ActiveSession, object)
 	for _, part := range parts.Part {
-		err = os.Remove(objectPath + fmt.Sprintf("$%d-$multiparts", part.PartNumber))
-		if err != nil {
+		if e = os.Remove(objectPath + fmt.Sprintf("$%d-$multiparts", part.PartNumber)); e != nil {
 			file.CloseAndPurge()
-			return ObjectMetadata{}, probe.NewError(err)
+			return ObjectMetadata{}, probe.NewError(e)
 		}
 	}
-	if err := os.Remove(objectPath + "$multiparts"); err != nil {
+	if e := os.Remove(objectPath + "$multiparts"); e != nil {
 		file.CloseAndPurge()
-		return ObjectMetadata{}, probe.NewError(err)
+		return ObjectMetadata{}, probe.NewError(e)
 	}
-	if err := saveMultipartsSession(fs.multiparts); err != nil {
+	if e := saveMultipartsSession(fs.multiparts); e != nil {
 		file.CloseAndPurge()
-		return ObjectMetadata{}, err.Trace()
+		return ObjectMetadata{}, e.Trace()
 	}
 	file.Close()
 
-	st, err := os.Stat(objectPath)
-	if err != nil {
-		return ObjectMetadata{}, probe.NewError(err)
+	st, e := os.Stat(objectPath)
+	if e != nil {
+		return ObjectMetadata{}, probe.NewError(e)
 	}
 	contentType := "application/octet-stream"
 	if objectExt := filepath.Ext(objectPath); objectExt != "" {
@@ -489,17 +485,16 @@ func (fs Filesystem) ListObjectParts(bucket, object string, resources ObjectReso
 	}
 
 	objectPath := filepath.Join(bucketPath, object)
-	multiPartfile, err := os.OpenFile(objectPath+"$multiparts", os.O_RDONLY, 0600)
-	if err != nil {
-		return ObjectResourcesMetadata{}, probe.NewError(err)
+	multiPartfile, e := os.OpenFile(objectPath+"$multiparts", os.O_RDONLY, 0600)
+	if e != nil {
+		return ObjectResourcesMetadata{}, probe.NewError(e)
 	}
 	defer multiPartfile.Close()
 
 	var deserializedMultipartSession MultipartSession
 	decoder := json.NewDecoder(multiPartfile)
-	err = decoder.Decode(&deserializedMultipartSession)
-	if err != nil {
-		return ObjectResourcesMetadata{}, probe.NewError(err)
+	if e = decoder.Decode(&deserializedMultipartSession); e != nil {
+		return ObjectResourcesMetadata{}, probe.NewError(e)
 	}
 	var parts []*PartMetadata
 	for i := startPartNumber; i <= deserializedMultipartSession.TotalParts; i++ {

pkg/fs/fs-object.go

@@ -26,7 +26,6 @@ import (
 	"crypto/md5"
 	"encoding/base64"
 	"encoding/hex"
-	"errors"
 	"runtime"
 
 	"github.com/minio/minio-xl/pkg/atomic"
@@ -34,6 +33,7 @@ import (
 	"github.com/minio/minio-xl/pkg/probe"
 	"github.com/minio/minio/pkg/contentdb"
 	"github.com/minio/minio/pkg/disk"
+	"github.com/minio/minio/pkg/ioutils"
 )
 
 /// Object Operations
@@ -169,22 +169,22 @@ func getMetadata(rootPath, bucket, object string) (ObjectMetadata, *probe.Error)
 }
 
 // isMD5SumEqual - returns error if md5sum mismatches, success its `nil`
-func isMD5SumEqual(expectedMD5Sum, actualMD5Sum string) *probe.Error {
+func isMD5SumEqual(expectedMD5Sum, actualMD5Sum string) bool {
 	if strings.TrimSpace(expectedMD5Sum) != "" && strings.TrimSpace(actualMD5Sum) != "" {
 		expectedMD5SumBytes, err := hex.DecodeString(expectedMD5Sum)
 		if err != nil {
-			return probe.NewError(err)
+			return false
 		}
 		actualMD5SumBytes, err := hex.DecodeString(actualMD5Sum)
 		if err != nil {
-			return probe.NewError(err)
+			return false
 		}
 		if !bytes.Equal(expectedMD5SumBytes, actualMD5SumBytes) {
-			return probe.NewError(BadDigest{Md5: expectedMD5Sum})
+			return false
 		}
-		return nil
+		return true
 	}
-	return probe.NewError(errors.New("invalid argument"))
+	return false
 }
 
 // CreateObject - PUT object
@@ -254,14 +254,12 @@ func (fs Filesystem) CreateObject(bucket, object, expectedMD5Sum string, size in
 	mw := io.MultiWriter(file, h, sh)
 
 	if size > 0 {
-		_, e = io.CopyN(mw, data, size)
-		if e != nil {
+		if _, e = io.CopyN(mw, data, size); e != nil {
 			file.CloseAndPurge()
 			return ObjectMetadata{}, probe.NewError(e)
 		}
 	} else {
-		_, e = io.Copy(mw, data)
-		if e != nil {
+		if _, e = io.Copy(mw, data); e != nil {
 			file.CloseAndPurge()
 			return ObjectMetadata{}, probe.NewError(e)
 		}
@@ -270,7 +268,7 @@ func (fs Filesystem) CreateObject(bucket, object, expectedMD5Sum string, size in
 	md5Sum := hex.EncodeToString(h.Sum(nil))
 	// Verify if the written object is equal to what is expected, only if it is requested as such
 	if strings.TrimSpace(expectedMD5Sum) != "" {
-		if e := isMD5SumEqual(strings.TrimSpace(expectedMD5Sum), md5Sum); e != nil {
+		if !isMD5SumEqual(strings.TrimSpace(expectedMD5Sum), md5Sum) {
 			file.CloseAndPurge()
 			return ObjectMetadata{}, probe.NewError(BadDigest{Md5: expectedMD5Sum, Bucket: bucket, Object: object})
 		}
@@ -312,7 +310,6 @@ func deleteObjectPath(basePath, deletePath, bucket, object string) *probe.Error
 	if basePath == deletePath {
 		return nil
 	}
-
 	fi, e := os.Stat(deletePath)
 	if e != nil {
 		if os.IsNotExist(e) {
@@ -321,15 +318,14 @@ func deleteObjectPath(basePath, deletePath, bucket, object string) *probe.Error
 		return probe.NewError(e)
 	}
 	if fi.IsDir() {
-		empty, err := isDirEmpty(deletePath)
-		if err != nil {
-			return err.Trace(deletePath)
+		empty, e := ioutils.IsDirEmpty(deletePath)
+		if e != nil {
+			return probe.NewError(e)
 		}
 		if !empty {
 			return nil
 		}
 	}
-
 	if e := os.Remove(deletePath); e != nil {
 		return probe.NewError(e)
 	}

pkg/fs/fs_test.go

@@ -33,12 +33,12 @@ var _ = Suite(&MySuite{})
 func (s *MySuite) TestAPISuite(c *C) {
 	var storageList []string
 	create := func() Filesystem {
-		path, err := ioutil.TempDir(os.TempDir(), "minio-")
-		c.Check(err, IsNil)
+		path, e := ioutil.TempDir(os.TempDir(), "minio-")
+		c.Check(e, IsNil)
 		storageList = append(storageList, path)
-		store, perr := New(path)
+		store, err := New(path)
 		store.SetMinFreeDisk(0)
-		c.Check(perr, IsNil)
+		c.Check(err, IsNil)
 		return store
 	}
 	APITestSuite(c, create)

pkg/ioutils/filepath.go

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package fs
+package ioutils
 
 import (
 	"errors"
@@ -22,20 +22,13 @@ import (
 	"os"
 	"path/filepath"
 	"sort"
-
-	"github.com/minio/minio-xl/pkg/probe"
 )
 
-// Check if a directory is empty
-func isDirEmpty(dirname string) (bool, *probe.Error) {
-	f, err := os.Open(dirname)
-	defer f.Close()
-	if err != nil {
-		return false, probe.NewError(err)
-	}
-	names, err := f.Readdirnames(1)
+// IsDirEmpty Check if a directory is empty
+func IsDirEmpty(dirname string) (bool, error) {
+	names, err := ReadDirNamesN(dirname, 1)
 	if err != nil && err != io.EOF {
-		return false, probe.NewError(err)
+		return false, err
 	}
 	if len(names) > 0 {
 		return false, nil
@@ -43,19 +36,9 @@ func isDirEmpty(dirname string) (bool, *probe.Error) {
 	return true, nil
 }
 
-// Walk walks the file tree rooted at root, calling walkFn for each file or
+// FTW walks the file tree rooted at root, calling walkFn for each file or
 // directory in the tree, including root.
-func Walk(root string, walkFn WalkFunc) error {
-	info, err := os.Lstat(root)
-	if err != nil {
-		return walkFn(root, nil, err)
-	}
-	return walk(root, info, walkFn)
-}
-
-// WalkUnsorted walks the file tree rooted at root, calling walkFn for each file or
-// directory in the tree, including root.
-func WalkUnsorted(root string, walkFn WalkFunc) error {
+func FTW(root string, walkFn FTWFunc) error {
 	info, err := os.Lstat(root)
 	if err != nil {
 		return walkFn(root, nil, err)
@@ -91,10 +74,12 @@ func readDirUnsortedNames(dirname string) ([]string, error) {
 		return nil, err
 	}
 	nameInfos, err := f.Readdir(-1)
-	f.Close()
 	if err != nil {
 		return nil, err
 	}
+	if err = f.Close(); err != nil {
+		return nil, err
+	}
 	var names []string
 	for _, nameInfo := range nameInfos {
 		names = append(names, getRealName(nameInfo))
@@ -102,12 +87,12 @@ func readDirUnsortedNames(dirname string) ([]string, error) {
 	return names, nil
 }
 
-// WalkFunc is the type of the function called for each file or directory
+// FTWFunc is the type of the function called for each file or directory
 // visited by Walk. The path argument contains the argument to Walk as a
 // prefix; that is, if Walk is called with "dir", which is a directory
 // containing the file "a", the walk function will be called with argument
 // "dir/a". The info argument is the os.FileInfo for the named path.
-type WalkFunc func(path string, info os.FileInfo, err error) error
+type FTWFunc func(path string, info os.FileInfo, err error) error
 
 // ErrSkipDir is used as a return value from WalkFuncs to indicate that
 // the directory named in the call is to be skipped. It is not returned
@@ -123,48 +108,8 @@ var ErrSkipFile = errors.New("skip this file")
 // file or a symlink left
 var ErrDirNotEmpty = errors.New("directory not empty")
 
-func walkUnsorted(path string, info os.FileInfo, walkFn WalkFunc) error {
-	err := walkFn(path, info, nil)
-	if err != nil {
-		if info.Mode().IsDir() && err == ErrSkipDir {
-			return nil
-		}
-		if info.Mode().IsRegular() && err == ErrSkipFile {
-			return nil
-		}
-		return err
-	}
-
-	if !info.IsDir() {
-		return nil
-	}
-
-	names, err := readDirUnsortedNames(path)
-	if err != nil {
-		return walkFn(path, info, err)
-	}
-	for _, name := range names {
-		filename := filepath.Join(path, name)
-		fileInfo, err := os.Lstat(filename)
-		if err != nil {
-			if err := walkFn(filename, fileInfo, err); err != nil && err != ErrSkipDir && err != ErrSkipFile {
-				return err
-			}
-		} else {
-			err = walk(filename, fileInfo, walkFn)
-			if err != nil {
-				if err == ErrSkipDir || err == ErrSkipFile {
-					return nil
-				}
-				return err
-			}
-		}
-	}
-	return nil
-}
-
-// walk recursively descends path, calling w.
-func walk(path string, info os.FileInfo, walkFn WalkFunc) error {
+// walk recursively descends path, calling walkFn.
+func walk(path string, info os.FileInfo, walkFn FTWFunc) error {
 	err := walkFn(path, info, nil)
 	if err != nil {
 		if info.Mode().IsDir() && err == ErrSkipDir {

server-main.go

@@ -170,35 +170,32 @@ func parsePercentToInt(s string, bitSize int) (int64, *probe.Error) {
 	i := strings.Index(s, "%")
 	if i < 0 {
 		// no percentage string found try to parse the whole string anyways
-		p, err := strconv.ParseInt(s, 10, bitSize)
-		if err != nil {
-			return 0, probe.NewError(err)
+		p, e := strconv.ParseInt(s, 10, bitSize)
+		if e != nil {
+			return 0, probe.NewError(e)
 		}
 		return p, nil
 	}
-	p, err := strconv.ParseInt(s[:i], 10, bitSize)
-	if err != nil {
-		return 0, probe.NewError(err)
+	p, e := strconv.ParseInt(s[:i], 10, bitSize)
+	if e != nil {
+		return 0, probe.NewError(e)
 	}
 	return p, nil
 }
 func setLogger(conf *configV2) *probe.Error {
 	if conf.IsMongoLoggingEnabled() {
-		err := log2Mongo(conf.MongoLogger.Addr, conf.MongoLogger.DB, conf.MongoLogger.Collection)
-		if err != nil {
-			return err.Trace()
+		if err := log2Mongo(conf.MongoLogger.Addr, conf.MongoLogger.DB, conf.MongoLogger.Collection); err != nil {
+			return err.Trace(conf.MongoLogger.Addr, conf.MongoLogger.DB, conf.MongoLogger.Collection)
 		}
 	}
 	if conf.IsSysloggingEnabled() {
-		err := log2Syslog(conf.SyslogLogger.Network, conf.SyslogLogger.Addr)
-		if err != nil {
-			return err.Trace()
+		if err := log2Syslog(conf.SyslogLogger.Network, conf.SyslogLogger.Addr); err != nil {
+			return err.Trace(conf.SyslogLogger.Network, conf.SyslogLogger.Addr)
 		}
 	}
 	if conf.IsFileLoggingEnabled() {
-		err := log2File(conf.FileLogger.Filename)
-		if err != nil {
-			return err.Trace()
+		if err := log2File(conf.FileLogger.Filename); err != nil {
+			return err.Trace(conf.FileLogger.Filename)
 		}
 	}
 	return nil
@@ -240,8 +237,8 @@ func (a accessKeys) String() string {
 
 // JSON - json formatted output
 func (a accessKeys) JSON() string {
-	b, err := json.Marshal(a)
-	errorIf(probe.NewError(err), "Unable to marshal json", nil)
+	b, e := json.Marshal(a)
+	errorIf(probe.NewError(e), "Unable to marshal json", nil)
 	return string(b)
 }
 
@@ -277,8 +274,8 @@ func checkServerSyntax(c *cli.Context) {
 func serverMain(c *cli.Context) {
 	checkServerSyntax(c)
 
-	conf, perr := initServer()
-	fatalIf(perr.Trace(), "Failed to read config for minio.", nil)
+	conf, err := initServer()
+	fatalIf(err.Trace(), "Failed to read config for minio.", nil)
 
 	certFile := c.GlobalString("cert")
 	keyFile := c.GlobalString("key")
@@ -299,7 +296,6 @@ func serverMain(c *cli.Context) {
 				fatalIf(probe.NewError(errInvalidArgument), "Minimum free disk should be set only once.", nil)
 			}
 			args = args.Tail()
-			var err *probe.Error
 			minFreeDisk, err = parsePercentToInt(args.First(), 64)
 			fatalIf(err.Trace(args.First()), "Invalid minium free disk size "+args.First()+" passed.", nil)
 			args = args.Tail()

server_fs_test.go

@@ -51,17 +51,17 @@ var _ = Suite(&MyAPIFSCacheSuite{})
 var testAPIFSCacheServer *httptest.Server
 
 func (s *MyAPIFSCacheSuite) SetUpSuite(c *C) {
-	root, err := ioutil.TempDir(os.TempDir(), "api-")
-	c.Assert(err, IsNil)
+	root, e := ioutil.TempDir(os.TempDir(), "api-")
+	c.Assert(e, IsNil)
 	s.root = root
 
-	fsroot, err := ioutil.TempDir(os.TempDir(), "api-")
-	c.Assert(err, IsNil)
+	fsroot, e := ioutil.TempDir(os.TempDir(), "api-")
+	c.Assert(e, IsNil)
 
-	accessKeyID, perr := generateAccessKeyID()
-	c.Assert(perr, IsNil)
-	secretAccessKey, perr := generateSecretAccessKey()
-	c.Assert(perr, IsNil)
+	accessKeyID, err := generateAccessKeyID()
+	c.Assert(err, IsNil)
+	secretAccessKey, err := generateSecretAccessKey()
+	c.Assert(err, IsNil)
 
 	conf := newConfigV2()
 	conf.Credentials.AccessKeyID = string(accessKeyID)
@@ -72,8 +72,7 @@ func (s *MyAPIFSCacheSuite) SetUpSuite(c *C) {
 	// do this only once here
 	setGlobalConfigPath(root)
 
-	perr = saveConfig(conf)
-	c.Assert(perr, IsNil)
+	c.Assert(saveConfig(conf), IsNil)
 
 	cloudServer := cloudServerConfig{
 		Path:        fsroot,

signature-handler.go

@@ -44,6 +44,13 @@ func isRequestSignatureV4(req *http.Request) bool {
 	return false
 }
 
+func isRequestRequiresACLCheck(req *http.Request) bool {
+	if isRequestSignatureV4(req) || isRequestPresignedSignatureV4(req) || isRequestPostPolicySignatureV4(req) {
+		return false
+	}
+	return true
+}
+
 func isRequestPresignedSignatureV4(req *http.Request) bool {
 	if _, ok := req.URL.Query()["X-Amz-Credential"]; ok {
 		return ok