From 6ea4d2c82de80efc87708e5e182034b7c6c2019e Mon Sep 17 00:00:00 2001 From: Gibheer Date: Thu, 5 Sep 2024 19:38:25 +0200 Subject: switch from github.com/lib/pq to github.com/jackc/pgx/v5 lib/pq is out of maintenance for some time now, so switch to the newer more active library. Looks like it finally stabilized after a long time. --- vendor/github.com/jackc/pgx/v5/pgproto3/backend.go | 292 +++++++++++++++++++++ 1 file changed, 292 insertions(+) create mode 100644 vendor/github.com/jackc/pgx/v5/pgproto3/backend.go (limited to 'vendor/github.com/jackc/pgx/v5/pgproto3/backend.go') diff --git a/vendor/github.com/jackc/pgx/v5/pgproto3/backend.go b/vendor/github.com/jackc/pgx/v5/pgproto3/backend.go new file mode 100644 index 0000000..d146c33 --- /dev/null +++ b/vendor/github.com/jackc/pgx/v5/pgproto3/backend.go @@ -0,0 +1,292 @@ +package pgproto3 + +import ( + "bytes" + "encoding/binary" + "fmt" + "io" +) + +// Backend acts as a server for the PostgreSQL wire protocol version 3. +type Backend struct { + cr *chunkReader + w io.Writer + + // tracer is used to trace messages when Send or Receive is called. This means an outbound message is traced + // before it is actually transmitted (i.e. before Flush). + tracer *tracer + + wbuf []byte + encodeError error + + // Frontend message flyweights + bind Bind + cancelRequest CancelRequest + _close Close + copyFail CopyFail + copyData CopyData + copyDone CopyDone + describe Describe + execute Execute + flush Flush + functionCall FunctionCall + gssEncRequest GSSEncRequest + parse Parse + query Query + sslRequest SSLRequest + startupMessage StartupMessage + sync Sync + terminate Terminate + + bodyLen int + maxBodyLen int // maxBodyLen is the maximum length of a message body in octets. If a message body exceeds this length, Receive will return an error. + 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(r io.Reader, w io.Writer) *Backend { + cr := newChunkReader(r, 0) + return &Backend{cr: cr, w: w} +} + +// Send sends a message to the frontend (i.e. the client). The message is buffered until Flush is called. Any error +// encountered will be returned from Flush. +func (b *Backend) Send(msg BackendMessage) { + if b.encodeError != nil { + return + } + + prevLen := len(b.wbuf) + newBuf, err := msg.Encode(b.wbuf) + if err != nil { + b.encodeError = err + return + } + b.wbuf = newBuf + + if b.tracer != nil { + b.tracer.traceMessage('B', int32(len(b.wbuf)-prevLen), msg) + } +} + +// Flush writes any pending messages to the frontend (i.e. the client). +func (b *Backend) Flush() error { + if err := b.encodeError; err != nil { + b.encodeError = nil + b.wbuf = b.wbuf[:0] + return &writeError{err: err, safeToRetry: true} + } + + n, err := b.w.Write(b.wbuf) + + const maxLen = 1024 + if len(b.wbuf) > maxLen { + b.wbuf = make([]byte, 0, maxLen) + } else { + b.wbuf = b.wbuf[:0] + } + + if err != nil { + return &writeError{err: err, safeToRetry: n == 0} + } + + return nil +} + +// Trace starts tracing the message traffic to w. It writes in a similar format to that produced by the libpq function +// PQtrace. +func (b *Backend) Trace(w io.Writer, options TracerOptions) { + b.tracer = &tracer{ + w: w, + buf: &bytes.Buffer{}, + TracerOptions: options, + } +} + +// Untrace stops tracing. +func (b *Backend) Untrace() { + b.tracer = nil +} + +// 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 + if b.maxBodyLen > 0 && b.bodyLen > b.maxBodyLen { + return nil, &ExceededMaxBodyLenErr{b.maxBodyLen, b.bodyLen} + } + 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.functionCall + 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 AuthTypeGSS, AuthTypeGSSCont: + msg = &GSSResponse{} + case AuthTypeCleartextPassword, AuthTypeMD5Password: + fallthrough + default: + // to maintain backwards compatibility + 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) + if err != nil { + return nil, err + } + + if b.tracer != nil { + b.tracer.traceMessage('F', int32(5+len(msgBody)), msg) + } + + return msg, nil +} + +// 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 +} + +// SetMaxBodyLen sets the maximum length of a message body in octets. If a message body exceeds this length, Receive will return +// an error. This is useful for protecting against malicious clients that send large messages with the intent of +// causing memory exhaustion. +// The default value is 0. +// If maxBodyLen is 0, then no maximum is enforced. +func (b *Backend) SetMaxBodyLen(maxBodyLen int) { + b.maxBodyLen = maxBodyLen +} -- cgit v1.2.3-70-g09d2