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TRspConnection.ReadReply to consume all "O" packets until a valid other packet is received. Fixes issue when status query after monitor command resulted in a qemu gdbserver state error as a result of incorrect acknowledge packets.

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This commit is contained in:
ccrause 2021-08-10 21:30:14 +02:00
parent f515d77c42
commit 29cf0ce9d6
1 changed files with 64 additions and 63 deletions
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127
components/fpdebug/fpdbgrsp.pas
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@ -287,83 +287,85 @@ var
c: char;
i: integer;
cksum, calcSum: byte;
outputPacket: boolean;
begin
Result := false;
if SockErr then exit;
i := 0;
retval := '';
repeat
c := chr(SafeReadByte);
inc(i);
retval := retval + c;
until (c = '$') or (i = failcountmax) or SockErr; // exit loop after start or count expired
if c <> '$' then
begin
DebugLn(DBG_WARNINGS, ['Warning: Timeout waiting for RSP reply']);
result := false;
repeat // Outer loop runs until no more "O" packets received
i := 0;
retval := '';
exit;
end
else if i > 1 then
DebugLn(DBG_WARNINGS, ['Warning: Discarding unexpected data before start of new message', retval])
else if SockErr then
DebugLn(DBG_WARNINGS, ['Warning: socket error.']);
repeat
c := chr(SafeReadByte);
inc(i);
retval := retval + c;
until (c = '$') or (i = failcountmax) or SockErr; // exit loop after start or count expired
c := chr(SafeReadByte);
retval := '';
calcSum := 0;
while c <> '#' do
begin
calcSum := byte(calcSum+byte(c));
if c=#$7D then // escape marker, unescape data
if c <> '$' then
begin
c := char(SafeReadByte);
DebugLn(DBG_WARNINGS, ['Warning: Timeout waiting for RSP reply']);
result := false;
retval := '';
exit;
end
else if i > 1 then
DebugLn(DBG_WARNINGS, ['Warning: Discarding unexpected data before start of new message', retval])
else if SockErr then
DebugLn(DBG_WARNINGS, ['Warning: socket error.']);
// Something weird happened
if c = '#' then
c := chr(SafeReadByte);
retval := '';
calcSum := 0;
while c <> '#' do
begin
calcSum := byte(calcSum+byte(c));
if c=#$7D then // escape marker, unescape data
begin
DebugLn(DBG_WARNINGS, ['Warning: Received end of packet marker in escaped sequence: ', c]);
break;
c := char(SafeReadByte);
// Something weird happened
if c = '#' then
begin
DebugLn(DBG_WARNINGS, ['Warning: Received end of packet marker in escaped sequence: ', c]);
break;
end;
calcSum := byte(calcSum + byte(c));
c := char(byte(c) xor $20);
end;
calcSum := byte(calcSum + byte(c));
c := char(byte(c) xor $20);
retval := retval + c;
c := char(SafeReadByte);
end;
retval := retval + c;
c := char(SafeReadByte);
end;
cksum := StrToInt('$' + char(SafeReadByte) + char(SafeReadByte));
if not (calcSum = cksum) then
DebugLn(DBG_WARNINGS, ['Warning: Reply packet with invalid checksum: ', retval]);
cksum := StrToInt('$' + char(SafeReadByte) + char(SafeReadByte));
if not (calcSum = cksum) then
DebugLn(DBG_WARNINGS, ['Warning: Reply packet with invalid checksum: ', retval]);
// Check if this packet is a console output packet, which isn't acknowledged
// Return empty retval
// Todo: display output somewhere
if (length(retval) > 2) and (retval[1] = 'O') then
begin
// Output should be hex encoded, length should be odd
if Odd(length(retval)) then
// Check if this packet is a console output packet, which isn't acknowledged
// Todo: display output somewhere
if (length(retval) > 2) and (retval[1] = 'O') and (retval[2] <> 'K') then
begin
delete(retval, 1, 1);
DebugLn(DBG_RSP, ['RSP <- <Console output> ', HexDecodeStr(retval)]);
outputPacket := True;
// Output should be hex encoded, length should be odd
if Odd(length(retval)) then
begin
delete(retval, 1, 1);
DebugLn(DBG_RSP, ['RSP <- <Console output> ', HexDecodeStr(retval)]);
end
else
DebugLn(DBG_WARNINGS, ['RSP <- <Possible unencoded output>: ', retval]);
end
else
DebugLn(DBG_WARNINGS, ['RSP <- <Possible unencoded output>: ', retval]);
result := false;
retval := '';
end
else
begin
SafeWriteByte(byte('+'));
result := not SockErr;
DebugLn(DBG_RSP, ['RSP <- ', retval]);
end;
begin
outputPacket := False;
end;
until not outputPacket;
SafeWriteByte(byte('+'));
result := not SockErr;
DebugLn(DBG_RSP, ['RSP <- ', retval]);
end;
function TRspConnection.SendCmdWaitForReply(const cmd: string; out reply: string
@ -933,8 +935,7 @@ begin
if Result and not((reply = 'OK') or ((length(reply) = 3) and (reply[1] = 'E'))) then
reply := HexDecodeStr(reply);
if reply <> 'OK' then
DebugLn(DBG_RSP, ['[Monitor '+s+'] reply: ', reply]);
DebugLn(DBG_RSP, ['[Monitor '+s+'] reply: ', reply]);
end;
end;
@ -1022,7 +1023,7 @@ begin
SendMonitorCmd('reset');
// Must be last init command, after init the debug loop waits for the response in WaitForSignal
res := SendCommand('?'); // Todo: should rather call SendCommandAck, but qemu doesn't send ACK for '?'
res := SendCommandAck('?');
finally
LeaveCriticalSection(fCS);
end;