// Process the identity ('I') message, reporting the identity therein.
func processIdentMsg(msgInit msgInit, exit exitFn) string {
var m femebe.Message
msgInit(&m, exit)
// Read the remote system identifier string
if m.MsgType() != 'I' {
exit("expected identification ('I') message, "+
"but received %c", m.MsgType())
}
// hard-coded lengh limit, but it's very generous
if m.Size() > 10*KB {
log.Printf("oversized message string, msg size is %d",
m.Size())
}
s, err := femebe.ReadCString(m.Payload())
if err != nil {
exit("couldn't read identification string: %v",
err)
}
return s
}
// Read the version message, calling exit if this is not a supported
// version.
func processVerMsg(msgInit msgInit, exit exitFn) {
var m femebe.Message
msgInit(&m, exit)
if m.MsgType() != 'V' {
exit("expected version ('V') message, "+
"but received %c", m.MsgType())
}
// hard-coded lengh limit, but it's very generous
if m.Size() > 10*KB {
log.Printf("oversized message string, msg size is %d",
m.Size())
}
s, err := femebe.ReadCString(m.Payload())
if err != nil {
exit("couldn't read version string: %v", err)
}
if !strings.HasPrefix(s, "PG-9.2.") ||
!strings.HasSuffix(s, "/logfebe-1") {
exit("protocol version not supported: %s", s)
}
}
// Process a log message, sending it to the client.
func processLogMsg(die dieCh, lpc *logplexc.Client, msgInit msgInit,
sr *serveRecord, exit exitFn) {
var m femebe.Message
for {
// Poll request to exit
select {
case <-die:
return
default:
break
}
msgInit(&m, exit)
// Refuse to handle any log message above an arbitrary
// size. Furthermore, exit the worker, closing the0
// connection, so that the client doesn't even bother
// to wait for this process to drain the oversized
// item and anything following it; these will be
// dropped. It's on the client to gracefully handle
// the error and re-connect after this happens.
if m.Size() > 1*MB {
exit("client %q sent oversized log record")
}
payload, err := m.Force()
if err != nil {
exit("could not retrieve payload of message: %v",
err)
}
var lr logRecord
parseLogRecord(&lr, payload, exit)
processLogRec(&lr, lpc, sr, exit)
}
}
func ReadStartupMessage(m *femebe.Message) (*Startup, error) {
var err error
if remainingSz := m.Size() - 4; remainingSz > 10000 {
// Startup packets longer than this are considered
// invalid. Copied from the PostgreSQL source code.
err = ErrTooBig{fmt.Errorf(
"Rejecting oversized startup packet: got %v",
m.Size())}
return nil, err
} else if remainingSz < 4 {
// We expect all initialization messages to
// have at least a 4-byte header
err = ErrWrongSize{
fmt.Errorf(
"Expected message of at least 4 bytes; got %v",
remainingSz)}
return nil, err
}
body, err := m.Force()
if err != nil {
return nil, err
}
var b femebe.Reader
b.InitReader(body)
protoVer, _ := femebe.ReadInt32(&b)
const SUPPORTED_PROTOVER = 0x00030000
if protoVer != SUPPORTED_PROTOVER {
err = ErrStartupVersion{
fmt.Errorf("bad version: got %x expected %x",
protoVer, SUPPORTED_PROTOVER)}
return nil, err
}
params := make(map[string]string)
for remaining := b.Len(); remaining > 1; {
key, err := femebe.ReadCString(&b)
if err != nil {
return nil, err
}
val, err := femebe.ReadCString(&b)
if err != nil {
return nil, err
}
remaining -= len(key) + len(val) + 2 /* null bytes */
params[key] = val
}
// Fidelity check on the startup packet, whereby the last byte
// must be a NUL.
if d, _ := femebe.ReadByte(&b); d != '\000' {
return nil, ErrStartupFmt{
errors.New("malformed startup packet")}
}
return &Startup{params}, nil
}