fix range gets with unspecified end range

The aws cli will send range gets of an object with ranges like
the following:
bytes=0-8388607
bytes=8388608-16777215
bytes=16777216-25165823
bytes=25165824-

The last one with the end offset unspecified just means the rest of
the object. So this fixes that case where there is only one offset
in the range.

backend/common.go

@@ -17,7 +17,6 @@ package backend
 import (
 	"crypto/md5"
 	"encoding/hex"
-	"errors"
 	"fmt"
 	"io/fs"
 	"strconv"
@@ -25,6 +24,7 @@ import (
 	"time"
 
 	"github.com/aws/aws-sdk-go-v2/service/s3/types"
+	"github.com/versity/versitygw/s3err"
 	"github.com/versity/versitygw/s3response"
 )
 
@@ -55,6 +55,12 @@ func GetTimePtr(t time.Time) *time.Time {
 	return &t
 }
 
+var (
+	errInvalidRange = s3err.GetAPIError(s3err.ErrInvalidRequest)
+)
+
+// ParseRange parses input range header and returns startoffset, length, and
+// error. If no endoffset specified, then length is set to -1.
 func ParseRange(file fs.FileInfo, acceptRange string) (int64, int64, error) {
 	if acceptRange == "" {
 		return 0, file.Size(), nil
@@ -63,29 +69,34 @@ func ParseRange(file fs.FileInfo, acceptRange string) (int64, int64, error) {
 	rangeKv := strings.Split(acceptRange, "=")
 
 	if len(rangeKv) < 2 {
-		return 0, 0, errors.New("invalid range parameter")
+		return 0, 0, errInvalidRange
 	}
 
 	bRange := strings.Split(rangeKv[1], "-")
-	if len(bRange) < 2 {
-		return 0, 0, errors.New("invalid range parameter")
+	if len(bRange) < 1 || len(bRange) > 2 {
+		return 0, 0, errInvalidRange
 	}
 
 	startOffset, err := strconv.ParseInt(bRange[0], 10, 64)
 	if err != nil {
-		return 0, 0, errors.New("invalid range parameter")
+		return 0, 0, errInvalidRange
 	}
 
-	endOffset, err := strconv.ParseInt(bRange[1], 10, 64)
+	endOffset := int64(-1)
+	if len(bRange) == 1 || bRange[1] == "" {
+		return startOffset, endOffset, nil
+	}
+
+	endOffset, err = strconv.ParseInt(bRange[1], 10, 64)
 	if err != nil {
-		return 0, 0, errors.New("invalid range parameter")
+		return 0, 0, errInvalidRange
 	}
 
 	if endOffset < startOffset {
-		return 0, 0, errors.New("invalid range parameter")
+		return 0, 0, errInvalidRange
 	}
 
-	return int64(startOffset), int64(endOffset - startOffset + 1), nil
+	return startOffset, endOffset - startOffset + 1, nil
 }
 
 func GetMultipartMD5(parts []types.Part) string {

backend/posix/posix.go

@@ -891,8 +891,11 @@ func (p *Posix) GetObject(bucket, object, acceptRange string, writer io.Writer)
 		return nil, err
 	}
 
-	if startOffset+length > fi.Size() {
-		// TODO: is ErrInvalidRequest correct here?
+	if length == -1 {
+		length = fi.Size() - startOffset + 1
+	}
+
+	if startOffset+length > fi.Size()+1 {
 		return nil, s3err.GetAPIError(s3err.ErrInvalidRequest)
 	}
 

backend/scoutfs/scoutfs.go

@@ -440,8 +440,11 @@ func (s *ScoutFS) GetObject(bucket, object, acceptRange string, writer io.Writer
 		return nil, err
 	}
 
+	if length == -1 {
+		length = fi.Size() - startOffset + 1
+	}
+
 	if startOffset+length > fi.Size() {
-		// TODO: is ErrInvalidRequest correct here?
 		return nil, s3err.GetAPIError(s3err.ErrInvalidRequest)
 	}
 

integration/tests.go

@@ -923,7 +923,34 @@ func TestRangeGet(s *S3Conf) {
 	}
 
 	// bytes range is inclusive, go range for second value is not
-	if !isSame(b, data[100:201]) {
+	if !isEqual(b, data[100:201]) {
+		failF("%v: data mismatch of range", testname)
+		return
+	}
+
+	rangeString = "bytes=100-"
+
+	ctx, cancel = context.WithTimeout(context.Background(), shortTimeout)
+	out, err = s3client.GetObject(ctx, &s3.GetObjectInput{
+		Bucket: &bucket,
+		Key:    &name,
+		Range:  &rangeString,
+	})
+	defer cancel()
+	if err != nil {
+		failF("%v: %v", testname, err)
+		return
+	}
+	defer out.Body.Close()
+
+	b, err = io.ReadAll(out.Body)
+	if err != nil {
+		failF("%v: read body %v", testname, err)
+		return
+	}
+
+	// bytes range is inclusive, go range for second value is not
+	if !isEqual(b, data[100:]) {
 		failF("%v: data mismatch of range", testname)
 		return
 	}

integration/utils.go

@@ -111,18 +111,6 @@ func containsPart(part int32, list []types.Part) bool {
 	return false
 }
 
-func isSame(a, b []byte) bool {
-	if len(a) != len(b) {
-		return false
-	}
-	for i, x := range a {
-		if x != b[i] {
-			return false
-		}
-	}
-	return true
-}
-
 // Checks if the slices contain the same objects, if the objects doesn't
 // contain map, slice, channel.
 func areTagsSame(tags1, tags2 []types.Tag) bool {