bagage/internal/encoding/ssh/filexfer/attrs.go
2021-11-19 19:54:49 +01:00

326 lines
8.1 KiB
Go

package filexfer
// Attributes related flags.
const (
AttrSize = 1 << iota // SSH_FILEXFER_ATTR_SIZE
AttrUIDGID // SSH_FILEXFER_ATTR_UIDGID
AttrPermissions // SSH_FILEXFER_ATTR_PERMISSIONS
AttrACModTime // SSH_FILEXFER_ACMODTIME
AttrExtended = 1 << 31 // SSH_FILEXFER_ATTR_EXTENDED
)
// Attributes defines the file attributes type defined in draft-ietf-secsh-filexfer-02
//
// Defined in: https://tools.ietf.org/html/draft-ietf-secsh-filexfer-02#section-5
type Attributes struct {
Flags uint32
// AttrSize
Size uint64
// AttrUIDGID
UID uint32
GID uint32
// AttrPermissions
Permissions FileMode
// AttrACmodTime
ATime uint32
MTime uint32
// AttrExtended
ExtendedAttributes []ExtendedAttribute
}
// GetSize returns the Size field and a bool that is true if and only if the value is valid/defined.
func (a *Attributes) GetSize() (size uint64, ok bool) {
return a.Size, a.Flags&AttrSize != 0
}
// SetSize is a convenience function that sets the Size field,
// and marks the field as valid/defined in Flags.
func (a *Attributes) SetSize(size uint64) {
a.Flags |= AttrSize
a.Size = size
}
// GetUIDGID returns the UID and GID fields and a bool that is true if and only if the values are valid/defined.
func (a *Attributes) GetUIDGID() (uid, gid uint32, ok bool) {
return a.UID, a.GID, a.Flags&AttrUIDGID != 0
}
// SetUIDGID is a convenience function that sets the UID and GID fields,
// and marks the fields as valid/defined in Flags.
func (a *Attributes) SetUIDGID(uid, gid uint32) {
a.Flags |= AttrUIDGID
a.UID = uid
a.GID = gid
}
// GetPermissions returns the Permissions field and a bool that is true if and only if the value is valid/defined.
func (a *Attributes) GetPermissions() (perms FileMode, ok bool) {
return a.Permissions, a.Flags&AttrPermissions != 0
}
// SetPermissions is a convenience function that sets the Permissions field,
// and marks the field as valid/defined in Flags.
func (a *Attributes) SetPermissions(perms FileMode) {
a.Flags |= AttrPermissions
a.Permissions = perms
}
// GetACModTime returns the ATime and MTime fields and a bool that is true if and only if the values are valid/defined.
func (a *Attributes) GetACModTime() (atime, mtime uint32, ok bool) {
return a.ATime, a.MTime, a.Flags&AttrACModTime != 0
return a.ATime, a.MTime, a.Flags&AttrACModTime != 0
}
// SetACModTime is a convenience function that sets the ATime and MTime fields,
// and marks the fields as valid/defined in Flags.
func (a *Attributes) SetACModTime(atime, mtime uint32) {
a.Flags |= AttrACModTime
a.ATime = atime
a.MTime = mtime
}
// Len returns the number of bytes a would marshal into.
func (a *Attributes) Len() int {
length := 4
if a.Flags&AttrSize != 0 {
length += 8
}
if a.Flags&AttrUIDGID != 0 {
length += 4 + 4
}
if a.Flags&AttrPermissions != 0 {
length += 4
}
if a.Flags&AttrACModTime != 0 {
length += 4 + 4
}
if a.Flags&AttrExtended != 0 {
length += 4
for _, ext := range a.ExtendedAttributes {
length += ext.Len()
}
}
return length
}
// MarshalInto marshals e onto the end of the given Buffer.
func (a *Attributes) MarshalInto(b *Buffer) {
b.AppendUint32(a.Flags)
if a.Flags&AttrSize != 0 {
b.AppendUint64(a.Size)
}
if a.Flags&AttrUIDGID != 0 {
b.AppendUint32(a.UID)
b.AppendUint32(a.GID)
}
if a.Flags&AttrPermissions != 0 {
b.AppendUint32(uint32(a.Permissions))
}
if a.Flags&AttrACModTime != 0 {
b.AppendUint32(a.ATime)
b.AppendUint32(a.MTime)
}
if a.Flags&AttrExtended != 0 {
b.AppendUint32(uint32(len(a.ExtendedAttributes)))
for _, ext := range a.ExtendedAttributes {
ext.MarshalInto(b)
}
}
}
// MarshalBinary returns a as the binary encoding of a.
func (a *Attributes) MarshalBinary() ([]byte, error) {
buf := NewBuffer(make([]byte, 0, a.Len()))
a.MarshalInto(buf)
return buf.Bytes(), nil
}
// UnmarshalFrom unmarshals an Attributes from the given Buffer into e.
//
// NOTE: The values of fields not covered in the a.Flags are explicitly undefined.
func (a *Attributes) UnmarshalFrom(b *Buffer) (err error) {
flags, err := b.ConsumeUint32()
if err != nil {
return err
}
return a.XXX_UnmarshalByFlags(flags, b)
}
// XXX_UnmarshalByFlags uses the pre-existing a.Flags field to determine which fields to decode.
// DO NOT USE THIS: it is an anti-corruption function to implement existing internal usage in pkg/sftp.
// This function is not a part of any compatibility promise.
func (a *Attributes) XXX_UnmarshalByFlags(flags uint32, b *Buffer) (err error) {
a.Flags = flags
// Short-circuit dummy attributes.
if a.Flags == 0 {
return nil
}
if a.Flags&AttrSize != 0 {
if a.Size, err = b.ConsumeUint64(); err != nil {
return err
}
}
if a.Flags&AttrUIDGID != 0 {
if a.UID, err = b.ConsumeUint32(); err != nil {
return err
}
if a.GID, err = b.ConsumeUint32(); err != nil {
return err
}
}
if a.Flags&AttrPermissions != 0 {
m, err := b.ConsumeUint32()
if err != nil {
return err
}
a.Permissions = FileMode(m)
}
if a.Flags&AttrACModTime != 0 {
if a.ATime, err = b.ConsumeUint32(); err != nil {
return err
}
if a.MTime, err = b.ConsumeUint32(); err != nil {
return err
}
}
if a.Flags&AttrExtended != 0 {
count, err := b.ConsumeUint32()
if err != nil {
return err
}
a.ExtendedAttributes = make([]ExtendedAttribute, count)
for i := range a.ExtendedAttributes {
a.ExtendedAttributes[i].UnmarshalFrom(b)
}
}
return nil
}
// UnmarshalBinary decodes the binary encoding of Attributes into e.
func (a *Attributes) UnmarshalBinary(data []byte) error {
return a.UnmarshalFrom(NewBuffer(data))
}
// ExtendedAttribute defines the extended file attribute type defined in draft-ietf-secsh-filexfer-02
//
// Defined in: https://tools.ietf.org/html/draft-ietf-secsh-filexfer-02#section-5
type ExtendedAttribute struct {
Type string
Data string
}
// Len returns the number of bytes e would marshal into.
func (e *ExtendedAttribute) Len() int {
return 4 + len(e.Type) + 4 + len(e.Data)
}
// MarshalInto marshals e onto the end of the given Buffer.
func (e *ExtendedAttribute) MarshalInto(b *Buffer) {
b.AppendString(e.Type)
b.AppendString(e.Data)
}
// MarshalBinary returns e as the binary encoding of e.
func (e *ExtendedAttribute) MarshalBinary() ([]byte, error) {
buf := NewBuffer(make([]byte, 0, e.Len()))
e.MarshalInto(buf)
return buf.Bytes(), nil
}
// UnmarshalFrom unmarshals an ExtendedAattribute from the given Buffer into e.
func (e *ExtendedAttribute) UnmarshalFrom(b *Buffer) (err error) {
if e.Type, err = b.ConsumeString(); err != nil {
return err
}
if e.Data, err = b.ConsumeString(); err != nil {
return err
}
return nil
}
// UnmarshalBinary decodes the binary encoding of ExtendedAttribute into e.
func (e *ExtendedAttribute) UnmarshalBinary(data []byte) error {
return e.UnmarshalFrom(NewBuffer(data))
}
// NameEntry implements the SSH_FXP_NAME repeated data type from draft-ietf-secsh-filexfer-02
//
// This type is incompatible with versions 4 or higher.
type NameEntry struct {
Filename string
Longname string
Attrs Attributes
}
// Len returns the number of bytes e would marshal into.
func (e *NameEntry) Len() int {
return 4 + len(e.Filename) + 4 + len(e.Longname) + e.Attrs.Len()
}
// MarshalInto marshals e onto the end of the given Buffer.
func (e *NameEntry) MarshalInto(b *Buffer) {
b.AppendString(e.Filename)
b.AppendString(e.Longname)
e.Attrs.MarshalInto(b)
}
// MarshalBinary returns e as the binary encoding of e.
func (e *NameEntry) MarshalBinary() ([]byte, error) {
buf := NewBuffer(make([]byte, 0, e.Len()))
e.MarshalInto(buf)
return buf.Bytes(), nil
}
// UnmarshalFrom unmarshals an NameEntry from the given Buffer into e.
//
// NOTE: The values of fields not covered in the a.Flags are explicitly undefined.
func (e *NameEntry) UnmarshalFrom(b *Buffer) (err error) {
if e.Filename, err = b.ConsumeString(); err != nil {
return err
}
if e.Longname, err = b.ConsumeString(); err != nil {
return err
}
return e.Attrs.UnmarshalFrom(b)
}
// UnmarshalBinary decodes the binary encoding of NameEntry into e.
func (e *NameEntry) UnmarshalBinary(data []byte) error {
return e.UnmarshalFrom(NewBuffer(data))
}