}

	cred.scope.region = credElements[1]
	// Verify if region is valid.
	sRegion := cred.scope.region
	// Region is set to be empty, we use whatever was sent by the
	// request and proceed further. This is a work-around to address
	// an important problem for ListBuckets() getting signed with
	// different regions.
	if region == "" {
		region = sRegion
	}

		isDistErasure: isDistErasure,
	}
	if isDistErasure {
		return &nsMutex
	}
	nsMutex.lockMap = make(map[string]*nsLock)
	return &nsMutex
}

// nsLock - provides primitives for locking critical namespace regions.
type nsLock struct {
	ref int32
	*lsync.LRWMutex
}

// nsLockMap - namespace lock map, provides primitives to Lock,
// Unlock, RLock and RUnlock.
type nsLockMap struct {

//
// If the current file is sparse and r is an io.ReadSeeker,
// then readFrom uses Seek to skip past holes defined in Header.SparseHoles,
// assuming that skipped regions are all NULs.
// This always reads the last byte to ensure r is the right size.
//
// TODO(dsnet): Re-export this when adding sparse file support.
// See https://golang.org/issue/22735

Note that by allowing for this limited form of manual memory allocation
that use-after-free bugs are possible with regular Go values. This package
limits the impact of these use-after-free bugs by preventing reuse of freed
memory regions until the garbage collector is able to determine that it is
safe. Typically, a use-after-free bug will result in a fault and a helpful
error message, but this package reserves the right to not force a fault on

// Read reads from the current file in the tar archive.
// It returns (0, io.EOF) when it reaches the end of that file,
// until [Next] is called to advance to the next file.
//
// If the current file is sparse, then the regions marked as a hole
// are read back as NUL-bytes.
//
// Calling Read on special types like [TypeLink], [TypeSymlink], [TypeChar],
// [TypeBlock], [TypeDir], and [TypeFifo] returns (0, [io.EOF]) regardless of what

	if accessKeyID == "" || secretAccessKey == "" {
		return errors.New("Presign cannot be generated without access and secret keys")
	}

	region := globalSite.Region
	date := UTCNow()
	scope := getScope(date, region)
	credential := fmt.Sprintf("%s/%s", accessKeyID, scope)

	// Set URL query.
	query := req.URL.Query()
	query.Set("X-Amz-Algorithm", signV4Algorithm)

	now := UTCNow()
	credentialTemplate := "%s/%s/%s/s3/aws4_request"

	region := globalSite.Region
	accessKeyID := globalActiveCred.AccessKey
	testCases := []struct {
		queryParams map[string]string
		headers     map[string]string
		region      string
		expected    APIErrorCode
	}{
		// (0) Should error without a set URL query.
		{
			region:   globalMinioDefaultRegion,
			expected: ErrInvalidQueryParams,
		},

	EnvUpdate = "MINIO_UPDATE"

	EnvEndpoints  = "MINIO_ENDPOINTS"   // legacy
	EnvWorm       = "MINIO_WORM"        // legacy
	EnvRegion     = "MINIO_REGION"      // legacy
	EnvRegionName = "MINIO_REGION_NAME" // legacy

)

// Expiration Token durations
// These values are used to validate the expiration time range from
// either the exp claim or MINI_STS_DURATION value
const (

		case cur.Offset > math.MaxInt64-cur.Length:
			return false // Integer overflow with large length
		case cur.endOffset() > size:
			return false // Region extends beyond the actual size
		case pre.endOffset() > cur.Offset:
			return false // Regions cannot overlap and must be in order
		}
		pre = cur
	}
	return true
}

// alignSparseEntries mutates src and returns dst where each fragment's

		if hkv.Key == key {
			return hkv, true
		}
	}
	return HelpKV{}, false
}

// DefaultComment used across all sub-systems.
const DefaultComment = "optionally add a comment to this setting"

// Region help is documented in default config
var (
	SiteHelp = HelpKVS{
		HelpKV{
			Key:         NameKey,
			Type:        "string",
			Description: `name for the site e.g. "cal-rack0"`,
			Optional:    true,
		},