diff options
Diffstat (limited to 'vendor/github.com/jackc/pgproto3/v2/backend.go')
-rw-r--r-- | vendor/github.com/jackc/pgproto3/v2/backend.go | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/vendor/github.com/jackc/pgproto3/v2/backend.go b/vendor/github.com/jackc/pgproto3/v2/backend.go new file mode 100644 index 000000000..e9ba38fc3 --- /dev/null +++ b/vendor/github.com/jackc/pgproto3/v2/backend.go @@ -0,0 +1,204 @@ +package pgproto3 + +import ( + "encoding/binary" + "fmt" + "io" +) + +// Backend acts as a server for the PostgreSQL wire protocol version 3. +type Backend struct { + cr ChunkReader + w io.Writer + + // Frontend message flyweights + bind Bind + cancelRequest CancelRequest + _close Close + copyFail CopyFail + copyData CopyData + copyDone CopyDone + describe Describe + execute Execute + flush Flush + gssEncRequest GSSEncRequest + parse Parse + query Query + sslRequest SSLRequest + startupMessage StartupMessage + sync Sync + terminate Terminate + + bodyLen int + msgType byte + partialMsg bool + authType uint32 +} + +const ( + minStartupPacketLen = 4 // minStartupPacketLen is a single 32-bit int version or code. + maxStartupPacketLen = 10000 // maxStartupPacketLen is MAX_STARTUP_PACKET_LENGTH from PG source. +) + +// NewBackend creates a new Backend. +func NewBackend(cr ChunkReader, w io.Writer) *Backend { + return &Backend{cr: cr, w: w} +} + +// Send sends a message to the frontend. +func (b *Backend) Send(msg BackendMessage) error { + _, err := b.w.Write(msg.Encode(nil)) + return err +} + +// ReceiveStartupMessage receives the initial connection message. This method is used of the normal Receive method +// because the initial connection message is "special" and does not include the message type as the first byte. This +// will return either a StartupMessage, SSLRequest, GSSEncRequest, or CancelRequest. +func (b *Backend) ReceiveStartupMessage() (FrontendMessage, error) { + buf, err := b.cr.Next(4) + if err != nil { + return nil, err + } + msgSize := int(binary.BigEndian.Uint32(buf) - 4) + + if msgSize < minStartupPacketLen || msgSize > maxStartupPacketLen { + return nil, fmt.Errorf("invalid length of startup packet: %d", msgSize) + } + + buf, err = b.cr.Next(msgSize) + if err != nil { + return nil, translateEOFtoErrUnexpectedEOF(err) + } + + code := binary.BigEndian.Uint32(buf) + + switch code { + case ProtocolVersionNumber: + err = b.startupMessage.Decode(buf) + if err != nil { + return nil, err + } + return &b.startupMessage, nil + case sslRequestNumber: + err = b.sslRequest.Decode(buf) + if err != nil { + return nil, err + } + return &b.sslRequest, nil + case cancelRequestCode: + err = b.cancelRequest.Decode(buf) + if err != nil { + return nil, err + } + return &b.cancelRequest, nil + case gssEncReqNumber: + err = b.gssEncRequest.Decode(buf) + if err != nil { + return nil, err + } + return &b.gssEncRequest, nil + default: + return nil, fmt.Errorf("unknown startup message code: %d", code) + } +} + +// Receive receives a message from the frontend. The returned message is only valid until the next call to Receive. +func (b *Backend) Receive() (FrontendMessage, error) { + if !b.partialMsg { + header, err := b.cr.Next(5) + if err != nil { + return nil, translateEOFtoErrUnexpectedEOF(err) + } + + b.msgType = header[0] + b.bodyLen = int(binary.BigEndian.Uint32(header[1:])) - 4 + b.partialMsg = true + } + + var msg FrontendMessage + switch b.msgType { + case 'B': + msg = &b.bind + case 'C': + msg = &b._close + case 'D': + msg = &b.describe + case 'E': + msg = &b.execute + case 'f': + msg = &b.copyFail + case 'd': + msg = &b.copyData + case 'c': + msg = &b.copyDone + case 'H': + msg = &b.flush + case 'P': + msg = &b.parse + case 'p': + switch b.authType { + case AuthTypeSASL: + msg = &SASLInitialResponse{} + case AuthTypeSASLContinue: + msg = &SASLResponse{} + case AuthTypeSASLFinal: + msg = &SASLResponse{} + case AuthTypeCleartextPassword, AuthTypeMD5Password: + fallthrough + default: + // to maintain backwards compatability + msg = &PasswordMessage{} + } + case 'Q': + msg = &b.query + case 'S': + msg = &b.sync + case 'X': + msg = &b.terminate + default: + return nil, fmt.Errorf("unknown message type: %c", b.msgType) + } + + msgBody, err := b.cr.Next(b.bodyLen) + if err != nil { + return nil, translateEOFtoErrUnexpectedEOF(err) + } + + b.partialMsg = false + + err = msg.Decode(msgBody) + return msg, err +} + +// SetAuthType sets the authentication type in the backend. +// Since multiple message types can start with 'p', SetAuthType allows +// contextual identification of FrontendMessages. For example, in the +// PG message flow documentation for PasswordMessage: +// +// Byte1('p') +// +// Identifies the message as a password response. Note that this is also used for +// GSSAPI, SSPI and SASL response messages. The exact message type can be deduced from +// the context. +// +// Since the Frontend does not know about the state of a backend, it is important +// to call SetAuthType() after an authentication request is received by the Frontend. +func (b *Backend) SetAuthType(authType uint32) error { + switch authType { + case AuthTypeOk, + AuthTypeCleartextPassword, + AuthTypeMD5Password, + AuthTypeSCMCreds, + AuthTypeGSS, + AuthTypeGSSCont, + AuthTypeSSPI, + AuthTypeSASL, + AuthTypeSASLContinue, + AuthTypeSASLFinal: + b.authType = authType + default: + return fmt.Errorf("authType not recognized: %d", authType) + } + + return nil +} |