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libpq: Trace all messages received from the server

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Not all messages that libpq received from the server would be sent
through our message tracing logic.  This commit tries to fix that by
introducing a new function pqParseDone which make it harder to forget
about doing so.

The messages that we now newly send through our tracing logic are:

- CopyData (received by COPY TO STDOUT)
- Authentication requests
- NegotiateProtocolVersion
- Some ErrorResponse messages during connection startup
- ReadyForQuery when received after a FunctionCall message

Author: Jelte Fennema-Nio <postgres@jeltef.nl>
Discussion: https://postgr.es/m/CAGECzQSoPHtZ4xe0raJ6FYSEiPPS+YWXBhOGo+Y1YecLgknF3g@mail.gmail.com
This commit is contained in:
Alvaro Herrera 2024-08-16 13:23:18 -04:00
parent 6be39d77a7
commit b8b3f861fb
No known key found for this signature in database
GPG Key ID: 1C20ACB9D5C564AE
6 changed files with 124 additions and 31 deletions
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21
src/interfaces/libpq/fe-auth.c
View File

@ -94,6 +94,10 @@ pg_GSS_continue(PGconn *conn, int payloadlen)
ginbuf.value = NULL;
}
/* finished parsing, trace server-to-client message */
if (conn->Pfdebug)
pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false);
/* Only try to acquire credentials if GSS delegation isn't disabled. */
if (!pg_GSS_have_cred_cache(&conn->gcred))
conn->gcred = GSS_C_NO_CREDENTIAL;
@ -258,6 +262,10 @@ pg_SSPI_continue(PGconn *conn, int payloadlen)
InBuffers[0].BufferType = SECBUFFER_TOKEN;
}
/* finished parsing, trace server-to-client message */
if (conn->Pfdebug)
pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false);
OutBuffers[0].pvBuffer = NULL;
OutBuffers[0].BufferType = SECBUFFER_TOKEN;
OutBuffers[0].cbBuffer = 0;
@ -563,6 +571,10 @@ pg_SASL_init(PGconn *conn, int payloadlen)
}
}
/* finished parsing, trace server-to-client message */
if (conn->Pfdebug)
pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false);
Assert(conn->sasl);
/*
@ -651,6 +663,11 @@ pg_SASL_continue(PGconn *conn, int payloadlen, bool final)
free(challenge);
return STATUS_ERROR;
}
/* finished parsing, trace server-to-client message */
if (conn->Pfdebug)
pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false);
/* For safety and convenience, ensure the buffer is NULL-terminated. */
challenge[payloadlen] = '\0';
@ -716,6 +733,10 @@ pg_password_sendauth(PGconn *conn, const char *password, AuthRequest areq)
return STATUS_ERROR; /* shouldn't happen */
}
/* finished parsing, trace server-to-client message */
if (conn->Pfdebug)
pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false);
/* Encrypt the password if needed. */
switch (areq)

12
src/interfaces/libpq/fe-connect.c
View File

@ -3797,7 +3797,7 @@ keep_going: /* We will come back to here until there is
return PGRES_POLLING_READING;
}
/* OK, we read the message; mark data consumed */
conn->inStart = conn->inCursor;
pqParseDone(conn, conn->inCursor);
/*
* Before 7.2, the postmaster didn't always end its
@ -3847,7 +3847,7 @@ keep_going: /* We will come back to here until there is
goto error_return;
}
/* OK, we read the message; mark data consumed */
conn->inStart = conn->inCursor;
pqParseDone(conn, conn->inCursor);
/*
* If error is "cannot connect now", try the next host if
@ -3876,7 +3876,7 @@ keep_going: /* We will come back to here until there is
goto error_return;
}
/* OK, we read the message; mark data consumed */
conn->inStart = conn->inCursor;
pqParseDone(conn, conn->inCursor);
goto error_return;
}
@ -3901,7 +3901,11 @@ keep_going: /* We will come back to here until there is
*/
res = pg_fe_sendauth(areq, msgLength, conn);
/* OK, we have processed the message; mark data consumed */
/*
* OK, we have processed the message; mark data consumed. We
* don't call pqParseDone here because we already traced this
* message inside pg_fe_sendauth.
*/
conn->inStart = conn->inCursor;
if (res != STATUS_OK)

15
src/interfaces/libpq/fe-misc.c
View File

@ -435,6 +435,21 @@ pqCheckInBufferSpace(size_t bytes_needed, PGconn *conn)
return EOF;
}
/*
* pqParseDone: after a server-to-client message has successfully
* been parsed, advance conn->inStart to account for it.
*/
void
pqParseDone(PGconn *conn, int newInStart)
{
/* trace server-to-client message */
if (conn->Pfdebug)
pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false);
/* Mark message as done */
conn->inStart = newInStart;
}
/*
* pqPutMsgStart: begin construction of a message to the server
*

38
src/interfaces/libpq/fe-protocol3.c
View File

@ -454,12 +454,8 @@ pqParseInput3(PGconn *conn)
/* Successfully consumed this message */
if (conn->inCursor == conn->inStart + 5 + msgLength)
{
/* trace server-to-client message */
if (conn->Pfdebug)
pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false);
/* Normal case: parsing agrees with specified length */
conn->inStart = conn->inCursor;
pqParseDone(conn, conn->inCursor);
}
else
{
@ -1728,12 +1724,8 @@ getCopyDataMessage(PGconn *conn)
return -1;
}
/* trace server-to-client message */
if (conn->Pfdebug)
pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false);
/* Drop the processed message and loop around for another */
conn->inStart = conn->inCursor;
pqParseDone(conn, conn->inCursor);
}
}
@ -1791,13 +1783,13 @@ pqGetCopyData3(PGconn *conn, char **buffer, int async)
(*buffer)[msgLength] = '\0'; /* Add terminating null */
/* Mark message consumed */
conn->inStart = conn->inCursor + msgLength;
pqParseDone(conn, conn->inCursor + msgLength);
return msgLength;
}
/* Empty, so drop it and loop around for another */
conn->inStart = conn->inCursor;
pqParseDone(conn, conn->inCursor);
}
}
@ -2168,8 +2160,9 @@ pqFunctionCall3(PGconn *conn, Oid fnid,
case 'Z': /* backend is ready for new query */
if (getReadyForQuery(conn))
continue;
/* consume the message and exit */
conn->inStart += 5 + msgLength;
/* consume the message */
pqParseDone(conn, conn->inStart + 5 + msgLength);
/*
* If we already have a result object (probably an error), use
@ -2194,6 +2187,7 @@ pqFunctionCall3(PGconn *conn, Oid fnid,
pqSaveErrorResult(conn);
}
}
/* and we're out */
return pqPrepareAsyncResult(conn);
case 'S': /* parameter status */
if (getParameterStatus(conn))
@ -2203,18 +2197,18 @@ pqFunctionCall3(PGconn *conn, Oid fnid,
/* The backend violates the protocol. */
libpq_append_conn_error(conn, "protocol error: id=0x%x", id);
pqSaveErrorResult(conn);
/* trust the specified message length as what to skip */
/*
* We can't call parsing done due to the protocol violation
* (so message tracing wouldn't work), but trust the specified
* message length as what to skip.
*/
conn->inStart += 5 + msgLength;
return pqPrepareAsyncResult(conn);
}
/* trace server-to-client message */
if (conn->Pfdebug)
pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false);
/* Completed this message, keep going */
/* trust the specified message length as what to skip */
conn->inStart += 5 + msgLength;
/* Completed parsing this message, keep going */
pqParseDone(conn, conn->inStart + 5 + msgLength);
needInput = false;
}

68
src/interfaces/libpq/fe-trace.c
View File

@ -280,6 +280,14 @@ pqTraceOutput_CommandComplete(FILE *f, const char *message, int *cursor)
pqTraceOutputString(f, message, cursor, false);
}
static void
pqTraceOutput_CopyData(FILE *f, const char *message, int *cursor, int length,
bool suppress)
{
fprintf(f, "CopyData\t");
pqTraceOutputNchar(f, length - *cursor + 1, message, cursor, suppress);
}
static void
pqTraceOutput_DataRow(FILE *f, const char *message, int *cursor)
{
@ -472,10 +480,58 @@ pqTraceOutput_Query(FILE *f, const char *message, int *cursor)
}
static void
pqTraceOutput_Authentication(FILE *f, const char *message, int *cursor)
pqTraceOutput_Authentication(FILE *f, const char *message, int *cursor,
int length, bool suppress)
{
fprintf(f, "Authentication\t");
pqTraceOutputInt32(f, message, cursor, false);
int authType = 0;
memcpy(&authType, message + *cursor, 4);
authType = (int) pg_ntoh32(authType);
*cursor += 4;
switch (authType)
{
case AUTH_REQ_OK:
fprintf(f, "AuthenticationOk");
break;
/* AUTH_REQ_KRB4 not supported */
/* AUTH_REQ_KRB5 not supported */
case AUTH_REQ_PASSWORD:
fprintf(f, "AuthenticationCleartextPassword");
break;
/* AUTH_REQ_CRYPT not supported */
case AUTH_REQ_MD5:
fprintf(f, "AuthenticationMD5Password");
break;
case AUTH_REQ_GSS:
fprintf(f, "AuthenticationGSS");
break;
case AUTH_REQ_GSS_CONT:
fprintf(f, "AuthenticationGSSContinue\t");
pqTraceOutputNchar(f, length - *cursor + 1, message, cursor,
suppress);
break;
case AUTH_REQ_SSPI:
fprintf(f, "AuthenticationSSPI");
break;
case AUTH_REQ_SASL:
fprintf(f, "AuthenticationSASL\t");
while (message[*cursor] != '\0')
pqTraceOutputString(f, message, cursor, false);
pqTraceOutputString(f, message, cursor, false);
break;
case AUTH_REQ_SASL_CONT:
fprintf(f, "AuthenticationSASLContinue\t");
pqTraceOutputNchar(f, length - *cursor + 1, message, cursor,
suppress);
break;
case AUTH_REQ_SASL_FIN:
fprintf(f, "AuthenticationSASLFinal\t");
pqTraceOutputNchar(f, length - *cursor + 1, message, cursor,
suppress);
break;
default:
fprintf(f, "Unknown authentication message %d", authType);
}
}
static void
@ -625,7 +681,8 @@ pqTraceOutputMessage(PGconn *conn, const char *message, bool toServer)
pqTraceOutput_CommandComplete(conn->Pfdebug, message, &logCursor);
break;
case PqMsg_CopyData:
/* Drop COPY data to reduce the overhead of logging. */
pqTraceOutput_CopyData(conn->Pfdebug, message, &logCursor,
length, regress);
break;
case PqMsg_Describe:
/* Describe(F) and DataRow(B) use the same identifier. */
@ -714,7 +771,8 @@ pqTraceOutputMessage(PGconn *conn, const char *message, bool toServer)
pqTraceOutput_Query(conn->Pfdebug, message, &logCursor);
break;
case PqMsg_AuthenticationRequest:
pqTraceOutput_Authentication(conn->Pfdebug, message, &logCursor);
pqTraceOutput_Authentication(conn->Pfdebug, message, &logCursor,
length, regress);
break;
case PqMsg_PortalSuspended:
fprintf(conn->Pfdebug, "PortalSuspended");

1
src/interfaces/libpq/libpq-int.h
View File

@ -753,6 +753,7 @@ extern PGresult *pqFunctionCall3(PGconn *conn, Oid fnid,
*/
extern int pqCheckOutBufferSpace(size_t bytes_needed, PGconn *conn);
extern int pqCheckInBufferSpace(size_t bytes_needed, PGconn *conn);
extern void pqParseDone(PGconn *conn, int newInStart);
extern int pqGetc(char *result, PGconn *conn);
extern int pqPutc(char c, PGconn *conn);
extern int pqGets(PQExpBuffer buf, PGconn *conn);