greenplumn fe-protocol3 源码
greenplumn fe-protocol3 代码
文件路径：/src/interfaces/libpq/fe-protocol3.c
/*-------------------------------------------------------------------------
*
* fe-protocol3.c
* functions that are specific to frontend/backend protocol version 3
*
* Portions Copyright (c) 2012-Present VMware, Inc. or its affiliates.
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/interfaces/libpq/fe-protocol3.c
*
*-------------------------------------------------------------------------
*/
/*
* This file is compiled with both frontend and backend codes, symlinked by
* src/backend/Makefile, and use macro FRONTEND to switch.
*
* Include "c.h" to adopt Greenplum C types. Don't include "postgres_fe.h",
* which only defines FRONTEND besides including "c.h"
*/
#include "c.h"
#include <ctype.h>
#include <fcntl.h>
#include "libpq-fe.h"
#include "libpq-int.h"
#include "nodes/pg_list.h"
#include "mb/pg_wchar.h"
#include "port/pg_bswap.h"
#ifdef WIN32
#include "win32.h"
#else
#include <unistd.h>
#ifdef HAVE_NETINET_TCP_H
#include <netinet/tcp.h>
#endif
#endif
/*
* This macro lists the backend message types that could be "long" (more
* than a couple of kilobytes).
*
* MPP-3628: explain-analyze of large subtrees can generate big messages.
*
* MPP-7971: allow AO to return information about large numbers of partitions.
*/
#define VALID_LONG_MESSAGE_TYPE(id) \
((id) == 'T' || (id) == 'D' || (id) == 'd' || (id) == 'V' || \
(id) == 'E' || (id) == 'N' || (id) == 'A' || (id) == 'Y' || \
(id) == 'y' || (id) == 'o')
static void handleSyncLoss(PGconn *conn, char id, int msgLength);
static int getRowDescriptions(PGconn *conn, int msgLength);
static int getParamDescriptions(PGconn *conn, int msgLength);
static int getAnotherTuple(PGconn *conn, int msgLength);
static int getParameterStatus(PGconn *conn);
static int getNotify(PGconn *conn);
static int getCopyStart(PGconn *conn, ExecStatusType copytype);
static int getReadyForQuery(PGconn *conn);
static void saveCdbStatMsg(PGresult *result, char *data, int len);
static void reportErrorPosition(PQExpBuffer msg, const char *query,
int loc, int encoding);
static int build_startup_packet(const PGconn *conn, char *packet,
const PQEnvironmentOption *options);
/*
* parseInput: if appropriate, parse input data from backend
* until input is exhausted or a stopping state is reached.
* Note that this function will NOT attempt to read more data from the backend.
*/
void
pqParseInput3(PGconn *conn)
{
char id;
int msgLength;
int avail;
#ifndef FRONTEND
int i;
int64 numRejected = 0;
int64 numCompleted = 0;
#endif
/*
* Loop to parse successive complete messages available in the buffer.
*/
for (;;)
{
/*
* Try to read a message. First get the type code and length. Return
* if not enough data.
*/
conn->inCursor = conn->inStart;
if (pqGetc(&id, conn))
return;
if (pqGetInt(&msgLength, 4, conn))
return;
/*
* Try to validate message type/length here. A length less than 4 is
* definitely broken. Large lengths should only be believed for a few
* message types.
*/
if (msgLength < 4)
{
handleSyncLoss(conn, id, msgLength);
return;
}
if (msgLength > 30000 && !VALID_LONG_MESSAGE_TYPE(id))
{
handleSyncLoss(conn, id, msgLength);
return;
}
/*
* Can't process if message body isn't all here yet.
*/
msgLength -= 4;
avail = conn->inEnd - conn->inCursor;
if (avail < msgLength)
{
/*
* Before returning, enlarge the input buffer if needed to hold
* the whole message. This is better than leaving it to
* pqReadData because we can avoid multiple cycles of realloc()
* when the message is large; also, we can implement a reasonable
* recovery strategy if we are unable to make the buffer big
* enough.
*/
if (pqCheckInBufferSpace(conn->inCursor + (size_t) msgLength,
conn))
{
/*
* XXX add some better recovery code... plan is to skip over
* the message using its length, then report an error. For the
* moment, just treat this like loss of sync (which indeed it
* might be!)
*/
handleSyncLoss(conn, id, msgLength);
}
return;
}
/*
* NOTIFY and NOTICE messages can happen in any state; always process
* them right away.
*
* Most other messages should only be processed while in BUSY state.
* (In particular, in READY state we hold off further parsing until
* the application collects the current PGresult.)
*
* However, if the state is IDLE then we got trouble; we need to deal
* with the unexpected message somehow.
*
* ParameterStatus ('S') messages are a special case: in IDLE state we
* must process 'em (this case could happen if a new value was adopted
* from config file due to SIGHUP), but otherwise we hold off until
* BUSY state.
*/
if (id == 'A')
{
if (getNotify(conn))
return;
}
else if (id == 'N')
{
if (pqGetErrorNotice3(conn, false))
return;
}
#ifndef FRONTEND
else if (id == 'k')
{
if (pqGetInt64(&(conn->mop_high_watermark), conn))
return;
}
else if (id == 'x')
{
if (pqGetc(&conn->wrote_xlog, conn))
return;
}
#endif
else if (conn->asyncStatus != PGASYNC_BUSY)
{
/* If not IDLE state, just wait ... */
if (conn->asyncStatus != PGASYNC_IDLE)
return;
/*
* Unexpected message in IDLE state; need to recover somehow.
* ERROR messages are handled using the notice processor;
* ParameterStatus is handled normally; anything else is just
* dropped on the floor after displaying a suitable warning
* notice. (An ERROR is very possibly the backend telling us why
* it is about to close the connection, so we don't want to just
* discard it...)
*/
if (id == 'E')
{
if (pqGetErrorNotice3(conn, false /* treat as notice */ ))
return;
}
else if (id == 'S')
{
if (getParameterStatus(conn))
return;
}
else
{
pqInternalNotice(&conn->noticeHooks,
"message type 0x%02x arrived from server while idle",
id);
/* Discard the unexpected message */
conn->inCursor += msgLength;
}
}
else
{
/*
* In BUSY state, we can process everything.
*/
switch (id)
{
case 'C': /* command complete */
if (pqGets(&conn->workBuffer, conn))
return;
if (conn->result == NULL)
{
conn->result = PQmakeEmptyPGresult(conn,
PGRES_COMMAND_OK);
if (!conn->result)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("out of memory"));
pqSaveErrorResult(conn);
}
}
if (conn->result)
strlcpy(conn->result->cmdStatus, conn->workBuffer.data,
CMDSTATUS_LEN);
conn->asyncStatus = PGASYNC_READY;
break;
case 'E': /* error return */
if (pqGetErrorNotice3(conn, true))
return;
conn->asyncStatus = PGASYNC_READY;
break;
case 'Z': /* backend is ready for new query */
if (getReadyForQuery(conn))
return;
conn->asyncStatus = PGASYNC_IDLE;
break;
case 'I': /* empty query */
if (conn->result == NULL)
{
conn->result = PQmakeEmptyPGresult(conn,
PGRES_EMPTY_QUERY);
if (!conn->result)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("out of memory"));
pqSaveErrorResult(conn);
}
}
conn->asyncStatus = PGASYNC_READY;
break;
case '1': /* Parse Complete */
/* If we're doing PQprepare, we're done; else ignore */
if (conn->queryclass == PGQUERY_PREPARE)
{
if (conn->result == NULL)
{
conn->result = PQmakeEmptyPGresult(conn,
PGRES_COMMAND_OK);
if (!conn->result)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("out of memory"));
pqSaveErrorResult(conn);
}
}
conn->asyncStatus = PGASYNC_READY;
}
break;
case '2': /* Bind Complete */
case '3': /* Close Complete */
/* Nothing to do for these message types */
break;
case 'S': /* parameter status */
if (getParameterStatus(conn))
return;
break;
case 'K': /* secret key data from the backend */
/*
* This is expected only during backend startup, but it's
* just as easy to handle it as part of the main loop.
* Save the data and continue processing.
*/
if (pqGetInt(&(conn->be_pid), 4, conn))
return;
if (pqGetInt(&(conn->be_key), 4, conn))
return;
break;
case 'T': /* Row Description */
if (conn->result != NULL &&
conn->result->resultStatus == PGRES_FATAL_ERROR)
{
/*
* We've already choked for some reason. Just discard
* the data till we get to the end of the query.
*/
conn->inCursor += msgLength;
}
else if (conn->result == NULL ||
conn->queryclass == PGQUERY_DESCRIBE)
{
/* First 'T' in a query sequence */
if (getRowDescriptions(conn, msgLength))
return;
/* getRowDescriptions() moves inStart itself */
continue;
}
else
{
/*
* A new 'T' message is treated as the start of
* another PGresult. (It is not clear that this is
* really possible with the current backend.) We stop
* parsing until the application accepts the current
* result.
*/
conn->asyncStatus = PGASYNC_READY;
return;
}
break;
case 'n': /* No Data */
/*
* NoData indicates that we will not be seeing a
* RowDescription message because the statement or portal
* inquired about doesn't return rows.
*
* If we're doing a Describe, we have to pass something
* back to the client, so set up a COMMAND_OK result,
* instead of TUPLES_OK. Otherwise we can just ignore
* this message.
*/
if (conn->queryclass == PGQUERY_DESCRIBE)
{
if (conn->result == NULL)
{
conn->result = PQmakeEmptyPGresult(conn,
PGRES_COMMAND_OK);
if (!conn->result)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("out of memory"));
pqSaveErrorResult(conn);
}
}
conn->asyncStatus = PGASYNC_READY;
}
break;
case 't': /* Parameter Description */
if (getParamDescriptions(conn, msgLength))
return;
/* getParamDescriptions() moves inStart itself */
continue;
case 'D': /* Data Row */
if (conn->result != NULL &&
conn->result->resultStatus == PGRES_TUPLES_OK)
{
/* Read another tuple of a normal query response */
if (getAnotherTuple(conn, msgLength))
return;
/* getAnotherTuple() moves inStart itself */
continue;
}
else if (conn->result != NULL &&
conn->result->resultStatus == PGRES_FATAL_ERROR)
{
/*
* We've already choked for some reason. Just discard
* tuples till we get to the end of the query.
*/
conn->inCursor += msgLength;
}
else
{
/* Set up to report error at end of query */
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("server sent data (\"D\" message) without prior row description (\"T\" message)\n"));
pqSaveErrorResult(conn);
/* Discard the unexpected message */
conn->inCursor += msgLength;
}
break;
case 'G': /* Start Copy In */
if (getCopyStart(conn, PGRES_COPY_IN))
return;
conn->asyncStatus = PGASYNC_COPY_IN;
break;
case 'H': /* Start Copy Out */
if (getCopyStart(conn, PGRES_COPY_OUT))
return;
conn->asyncStatus = PGASYNC_COPY_OUT;
conn->copy_already_done = 0;
break;
case 'W': /* Start Copy Both */
if (getCopyStart(conn, PGRES_COPY_BOTH))
return;
conn->asyncStatus = PGASYNC_COPY_BOTH;
conn->copy_already_done = 0;
break;
case 'd': /* Copy Data */
/*
* If we see Copy Data, just silently drop it. This would
* only occur if application exits COPY OUT mode too
* early.
*/
conn->inCursor += msgLength;
break;
case 'c': /* Copy Done */
/*
* If we see Copy Done, just silently drop it. This is
* the normal case during PQendcopy. We will keep
* swallowing data, expecting to see command-complete for
* the COPY command.
*/
break;
#ifndef FRONTEND
case 'j':
/*
* QE COPY reports number of rejected rows to the QD COPY
* in single row error handling mode.
*/
if (conn->result == NULL)
{
conn->result = PQmakeEmptyPGresult(conn, PGRES_COMMAND_OK);
if (!conn->result)
return;
}
if (pqGetInt64(&numRejected, conn))
return;
conn->result->numRejected += numRejected;
/* Optionally receive completed number when COPY FROM */
if (msgLength >= 12 && !pqGetInt64(&numCompleted, conn))
{
conn->result->numCompleted += numCompleted;
}
break;
case 'Y': /* CDB: statistical response from QE to QD */
/* for certain queries, the stats may arrive
* before the completion status -- for this case
* we're responsible for allocating the result
* struct */
if (conn->result == NULL)
conn->result = PQmakeEmptyPGresult(conn, PGRES_COMMAND_OK);
if (conn->result)
saveCdbStatMsg(conn->result,
conn->inBuffer + conn->inCursor,
msgLength);
conn->inCursor += msgLength;
break;
case 'y':
/*
* CDB: for gang management and stats collection.
*/
if (pqGets(&conn->workBuffer, conn))
return;
if (conn->result == NULL)
{
conn->result = PQmakeEmptyPGresult(conn,
PGRES_COMMAND_OK);
if (!conn->result)
return;
}
strlcpy(conn->result->cmdStatus, conn->workBuffer.data,
CMDSTATUS_LEN);
{
char ready = '0';
/* Whether mark the result ready */
if (pqGetc(&ready, conn))
return;
if (pqGetInt((int *)&conn->result->extraType, sizeof(PGExtraType), conn))
return;
if (pqGetInt(&conn->result->extraslen, 4, conn))
return;
conn->result->extras = malloc(conn->result->extraslen);
if (pqGetnchar((char *)conn->result->extras, conn->result->extraslen, conn))
return;
if (ready)
conn->asyncStatus = PGASYNC_READY;
}
break;
case 'w':
/*
* 'commit prepared' and 'one-phase commit' reports a list of gxids
* that the transaction has waited.
*/
if (conn->result == NULL)
{
conn->result = PQmakeEmptyPGresult(conn, PGRES_COMMAND_OK);
if (!conn->result)
return;
}
if (pqGetInt(&conn->result->nWaits, 4, conn))
return;
if (conn->result->nWaits > 0)
{
if (conn->result->waitGxids == NULL)
conn->result->waitGxids =
malloc(sizeof(int) * conn->result->nWaits);
for (i = 0; i < conn->result->nWaits; i++)
{
int gxid;
if (pqGetInt(&gxid, 4, conn))
return;
conn->result->waitGxids[i] = gxid;
}
}
break;
#endif
default:
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext(
"unexpected response from server; first received character was \"%c\"\n"),
id);
/* build an error result holding the error message */
pqSaveErrorResult(conn);
/* not sure if we will see more, so go to ready state */
conn->asyncStatus = PGASYNC_READY;
/* Discard the unexpected message */
conn->inCursor += msgLength;
break;
} /* switch on protocol character */
}
/* Successfully consumed this message */
if (conn->inCursor == conn->inStart + 5 + msgLength)
{
/* Normal case: parsing agrees with specified length */
conn->inStart = conn->inCursor;
}
else
{
/* Trouble --- report it */
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("message contents do not agree with length in message type \"%c\"\n"),
id);
/* build an error result holding the error message */
pqSaveErrorResult(conn);
conn->asyncStatus = PGASYNC_READY;
/* trust the specified message length as what to skip */
conn->inStart += 5 + msgLength;
}
}
}
/*
* handleSyncLoss: clean up after loss of message-boundary sync
*
* There isn't really a lot we can do here except abandon the connection.
*/
static void
handleSyncLoss(PGconn *conn, char id, int msgLength)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext(
"lost synchronization with server: got message type \"%c\", length %d\n"),
id, msgLength);
/* build an error result holding the error message */
pqSaveErrorResult(conn);
conn->asyncStatus = PGASYNC_READY; /* drop out of GetResult wait loop */
/* flush input data since we're giving up on processing it */
pqDropConnection(conn, true);
conn->status = CONNECTION_BAD; /* No more connection to backend */
}
/*
* parseInput subroutine to read a 'T' (row descriptions) message.
* We'll build a new PGresult structure (unless called for a Describe
* command for a prepared statement) containing the attribute data.
* Returns: 0 if processed message successfully, EOF to suspend parsing
* (the latter case is not actually used currently).
* In the former case, conn->inStart has been advanced past the message.
*/
static int
getRowDescriptions(PGconn *conn, int msgLength)
{
PGresult *result;
int nfields;
const char *errmsg;
int i;
/*
* When doing Describe for a prepared statement, there'll already be a
* PGresult created by getParamDescriptions, and we should fill data into
* that. Otherwise, create a new, empty PGresult.
*/
if (conn->queryclass == PGQUERY_DESCRIBE)
{
if (conn->result)
result = conn->result;
else
result = PQmakeEmptyPGresult(conn, PGRES_COMMAND_OK);
}
else
result = PQmakeEmptyPGresult(conn, PGRES_TUPLES_OK);
if (!result)
{
errmsg = NULL; /* means "out of memory", see below */
goto advance_and_error;
}
/* parseInput already read the 'T' label and message length. */
/* the next two bytes are the number of fields */
if (pqGetInt(&(result->numAttributes), 2, conn))
{
/* We should not run out of data here, so complain */
errmsg = libpq_gettext("insufficient data in \"T\" message");
goto advance_and_error;
}
nfields = result->numAttributes;
/* allocate space for the attribute descriptors */
if (nfields > 0)
{
result->attDescs = (PGresAttDesc *)
pqResultAlloc(result, nfields * sizeof(PGresAttDesc), true);
if (!result->attDescs)
{
errmsg = NULL; /* means "out of memory", see below */
goto advance_and_error;
}
MemSet(result->attDescs, 0, nfields * sizeof(PGresAttDesc));
}
/* result->binary is true only if ALL columns are binary */
result->binary = (nfields > 0) ? 1 : 0;
/* get type info */
for (i = 0; i < nfields; i++)
{
int tableid;
int columnid;
int typid;
int typlen;
int atttypmod;
int format;
if (pqGets(&conn->workBuffer, conn) ||
pqGetInt(&tableid, 4, conn) ||
pqGetInt(&columnid, 2, conn) ||
pqGetInt(&typid, 4, conn) ||
pqGetInt(&typlen, 2, conn) ||
pqGetInt(&atttypmod, 4, conn) ||
pqGetInt(&format, 2, conn))
{
/* We should not run out of data here, so complain */
errmsg = libpq_gettext("insufficient data in \"T\" message");
goto advance_and_error;
}
/*
* Since pqGetInt treats 2-byte integers as unsigned, we need to
* coerce these results to signed form.
*/
columnid = (int) ((int16) columnid);
typlen = (int) ((int16) typlen);
format = (int) ((int16) format);
result->attDescs[i].name = pqResultStrdup(result,
conn->workBuffer.data);
if (!result->attDescs[i].name)
{
errmsg = NULL; /* means "out of memory", see below */
goto advance_and_error;
}
result->attDescs[i].tableid = tableid;
result->attDescs[i].columnid = columnid;
result->attDescs[i].format = format;
result->attDescs[i].typid = typid;
result->attDescs[i].typlen = typlen;
result->attDescs[i].atttypmod = atttypmod;
if (format != 1)
result->binary = 0;
}
/* Sanity check that we absorbed all the data */
if (conn->inCursor != conn->inStart + 5 + msgLength)
{
errmsg = libpq_gettext("extraneous data in \"T\" message");
goto advance_and_error;
}
/* Success! */
conn->result = result;
/* Advance inStart to show that the "T" message has been processed. */
conn->inStart = conn->inCursor;
/*
* If we're doing a Describe, we're done, and ready to pass the result
* back to the client.
*/
if (conn->queryclass == PGQUERY_DESCRIBE)
{
conn->asyncStatus = PGASYNC_READY;
return 0;
}
/*
* We could perform additional setup for the new result set here, but for
* now there's nothing else to do.
*/
/* And we're done. */
return 0;
advance_and_error:
/* Discard unsaved result, if any */
if (result && result != conn->result)
PQclear(result);
/* Discard the failed message by pretending we read it */
conn->inStart += 5 + msgLength;
/*
* Replace partially constructed result with an error result. First
* discard the old result to try to win back some memory.
*/
pqClearAsyncResult(conn);
/*
* If preceding code didn't provide an error message, assume "out of
* memory" was meant. The advantage of having this special case is that
* freeing the old result first greatly improves the odds that gettext()
* will succeed in providing a translation.
*/
if (!errmsg)
errmsg = libpq_gettext("out of memory for query result");
printfPQExpBuffer(&conn->errorMessage, "%s\n", errmsg);
pqSaveErrorResult(conn);
/*
* Return zero to allow input parsing to continue. Subsequent "D"
* messages will be ignored until we get to end of data, since an error
* result is already set up.
*/
return 0;
}
/*
* parseInput subroutine to read a 't' (ParameterDescription) message.
* We'll build a new PGresult structure containing the parameter data.
* Returns: 0 if completed message, EOF if not enough data yet.
* In the former case, conn->inStart has been advanced past the message.
*
* Note that if we run out of data, we have to release the partially
* constructed PGresult, and rebuild it again next time. Fortunately,
* that shouldn't happen often, since 't' messages usually fit in a packet.
*/
static int
getParamDescriptions(PGconn *conn, int msgLength)
{
PGresult *result;
const char *errmsg = NULL; /* means "out of memory", see below */
int nparams;
int i;
result = PQmakeEmptyPGresult(conn, PGRES_COMMAND_OK);
if (!result)
goto advance_and_error;
/* parseInput already read the 't' label and message length. */
/* the next two bytes are the number of parameters */
if (pqGetInt(&(result->numParameters), 2, conn))
goto not_enough_data;
nparams = result->numParameters;
/* allocate space for the parameter descriptors */
if (nparams > 0)
{
result->paramDescs = (PGresParamDesc *)
pqResultAlloc(result, nparams * sizeof(PGresParamDesc), true);
if (!result->paramDescs)
goto advance_and_error;
MemSet(result->paramDescs, 0, nparams * sizeof(PGresParamDesc));
}
/* get parameter info */
for (i = 0; i < nparams; i++)
{
int typid;
if (pqGetInt(&typid, 4, conn))
goto not_enough_data;
result->paramDescs[i].typid = typid;
}
/* Sanity check that we absorbed all the data */
if (conn->inCursor != conn->inStart + 5 + msgLength)
{
errmsg = libpq_gettext("extraneous data in \"t\" message");
goto advance_and_error;
}
/* Success! */
conn->result = result;
/* Advance inStart to show that the "t" message has been processed. */
conn->inStart = conn->inCursor;
return 0;
not_enough_data:
PQclear(result);
return EOF;
advance_and_error:
/* Discard unsaved result, if any */
if (result && result != conn->result)
PQclear(result);
/* Discard the failed message by pretending we read it */
conn->inStart += 5 + msgLength;
/*
* Replace partially constructed result with an error result. First
* discard the old result to try to win back some memory.
*/
pqClearAsyncResult(conn);
/*
* If preceding code didn't provide an error message, assume "out of
* memory" was meant. The advantage of having this special case is that
* freeing the old result first greatly improves the odds that gettext()
* will succeed in providing a translation.
*/
if (!errmsg)
errmsg = libpq_gettext("out of memory");
printfPQExpBuffer(&conn->errorMessage, "%s\n", errmsg);
pqSaveErrorResult(conn);
/*
* Return zero to allow input parsing to continue. Essentially, we've
* replaced the COMMAND_OK result with an error result, but since this
* doesn't affect the protocol state, it's fine.
*/
return 0;
}
/*
* parseInput subroutine to read a 'D' (row data) message.
* We fill rowbuf with column pointers and then call the row processor.
* Returns: 0 if processed message successfully, EOF to suspend parsing
* (the latter case is not actually used currently).
* In the former case, conn->inStart has been advanced past the message.
*/
static int
getAnotherTuple(PGconn *conn, int msgLength)
{
PGresult *result = conn->result;
int nfields = result->numAttributes;
const char *errmsg;
PGdataValue *rowbuf;
int tupnfields; /* # fields from tuple */
int vlen; /* length of the current field value */
int i;
/* Get the field count and make sure it's what we expect */
if (pqGetInt(&tupnfields, 2, conn))
{
/* We should not run out of data here, so complain */
errmsg = libpq_gettext("insufficient data in \"D\" message");
goto advance_and_error;
}
if (tupnfields != nfields)
{
errmsg = libpq_gettext("unexpected field count in \"D\" message");
goto advance_and_error;
}
/* Resize row buffer if needed */
rowbuf = conn->rowBuf;
if (nfields > conn->rowBufLen)
{
rowbuf = (PGdataValue *) realloc(rowbuf,
nfields * sizeof(PGdataValue));
if (!rowbuf)
{
errmsg = NULL; /* means "out of memory", see below */
goto advance_and_error;
}
conn->rowBuf = rowbuf;
conn->rowBufLen = nfields;
}
/* Scan the fields */
for (i = 0; i < nfields; i++)
{
/* get the value length */
if (pqGetInt(&vlen, 4, conn))
{
/* We should not run out of data here, so complain */
errmsg = libpq_gettext("insufficient data in \"D\" message");
goto advance_and_error;
}
rowbuf[i].len = vlen;
/*
* rowbuf[i].value always points to the next address in the data
* buffer even if the value is NULL. This allows row processors to
* estimate data sizes more easily.
*/
rowbuf[i].value = conn->inBuffer + conn->inCursor;
/* Skip over the data value */
if (vlen > 0)
{
if (pqSkipnchar(vlen, conn))
{
/* We should not run out of data here, so complain */
errmsg = libpq_gettext("insufficient data in \"D\" message");
goto advance_and_error;
}
}
}
/* Sanity check that we absorbed all the data */
if (conn->inCursor != conn->inStart + 5 + msgLength)
{
errmsg = libpq_gettext("extraneous data in \"D\" message");
goto advance_and_error;
}
/* Advance inStart to show that the "D" message has been processed. */
conn->inStart = conn->inCursor;
/* Process the collected row */
errmsg = NULL;
if (pqRowProcessor(conn, &errmsg))
return 0; /* normal, successful exit */
goto set_error_result; /* pqRowProcessor failed, report it */
advance_and_error:
/* Discard the failed message by pretending we read it */
conn->inStart += 5 + msgLength;
set_error_result:
/*
* Replace partially constructed result with an error result. First
* discard the old result to try to win back some memory.
*/
pqClearAsyncResult(conn);
/*
* If preceding code didn't provide an error message, assume "out of
* memory" was meant. The advantage of having this special case is that
* freeing the old result first greatly improves the odds that gettext()
* will succeed in providing a translation.
*/
if (!errmsg)
errmsg = libpq_gettext("out of memory for query result");
printfPQExpBuffer(&conn->errorMessage, "%s\n", errmsg);
pqSaveErrorResult(conn);
/*
* Return zero to allow input parsing to continue. Subsequent "D"
* messages will be ignored until we get to end of data, since an error
* result is already set up.
*/
return 0;
}
/*
* Attempt to read an Error or Notice response message.
* This is possible in several places, so we break it out as a subroutine.
* Entry: 'E' or 'N' message type and length have already been consumed.
* Exit: returns 0 if successfully consumed message.
* returns EOF if not enough data.
*/
int
pqGetErrorNotice3(PGconn *conn, bool isError)
{
PGresult *res = NULL;
bool have_position = false;
PQExpBufferData workBuf;
char id;
/*
* If this is an error message, pre-emptively clear any incomplete query
* result we may have. We'd just throw it away below anyway, and
* releasing it before collecting the error might avoid out-of-memory.
*/
if (isError)
pqClearAsyncResult(conn);
/*
* Since the fields might be pretty long, we create a temporary
* PQExpBuffer rather than using conn->workBuffer. workBuffer is intended
* for stuff that is expected to be short. We shouldn't use
* conn->errorMessage either, since this might be only a notice.
*/
initPQExpBuffer(&workBuf);
/*
* Make a PGresult to hold the accumulated fields. We temporarily lie
* about the result status, so that PQmakeEmptyPGresult doesn't uselessly
* copy conn->errorMessage.
*
* NB: This allocation can fail, if you run out of memory. The rest of the
* function handles that gracefully, and we still try to set the error
* message as the connection's error message.
*/
res = PQmakeEmptyPGresult(conn, PGRES_EMPTY_QUERY);
if (res)
res->resultStatus = isError ? PGRES_FATAL_ERROR : PGRES_NONFATAL_ERROR;
/*
* Read the fields and save into res.
*
* While at it, save the SQLSTATE in conn->last_sqlstate, and note whether
* we saw a PG_DIAG_STATEMENT_POSITION field.
*/
for (;;)
{
if (pqGetc(&id, conn))
goto fail;
if (id == '\0')
break; /* terminator found */
if (pqGets(&workBuf, conn))
goto fail;
pqSaveMessageField(res, id, workBuf.data);
if (id == PG_DIAG_SQLSTATE)
strlcpy(conn->last_sqlstate, workBuf.data,
sizeof(conn->last_sqlstate));
else if (id == PG_DIAG_STATEMENT_POSITION)
have_position = true;
}
/*
* Save the active query text, if any, into res as well; but only if we
* might need it for an error cursor display, which is only true if there
* is a PG_DIAG_STATEMENT_POSITION field.
*/
if (have_position && conn->last_query && res)
res->errQuery = pqResultStrdup(res, conn->last_query);
/*
* Now build the "overall" error message for PQresultErrorMessage.
*/
resetPQExpBuffer(&workBuf);
pqBuildErrorMessage3(&workBuf, res, conn->verbosity, conn->show_context);
/*
* Either save error as current async result, or just emit the notice.
*/
if (isError)
{
if (res)
res->errMsg = pqResultStrdup(res, workBuf.data);
/* CDB: Transfer statistical messages on to the new result. */
if (conn->result &&
conn->result->cdbstats)
{
pgCdbStatCell *cell;
pgCdbStatCell *next;
pgCdbStatCell *prev = NULL;
/* Copy messages (incidentally reversing the list). */
for (cell = conn->result->cdbstats; cell; cell = cell->next)
saveCdbStatMsg(res, cell->data, cell->len);
/* Reverse the list again to restore newest-first ordering. */
for (cell = res->cdbstats; cell; cell = next)
{
next = cell->next;
cell->next = prev;
prev = cell;
}
res->cdbstats = prev;
}
pqClearAsyncResult(conn); /* redundant, but be safe */
conn->result = res;
if (PQExpBufferDataBroken(workBuf))
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("out of memory"));
else
appendPQExpBufferStr(&conn->errorMessage, workBuf.data);
}
else
{
/* if we couldn't allocate the result set, just discard the NOTICE */
if (res)
{
/* We can cheat a little here and not copy the message. */
res->errMsg = workBuf.data;
if (res->noticeHooks.noticeRec != NULL)
res->noticeHooks.noticeRec(res->noticeHooks.noticeRecArg, res);
PQclear(res);
}
}
termPQExpBuffer(&workBuf);
return 0;
fail:
PQclear(res);
termPQExpBuffer(&workBuf);
return EOF;
}
/*
* Construct an error message from the fields in the given PGresult,
* appending it to the contents of "msg".
*/
void
pqBuildErrorMessage3(PQExpBuffer msg, const PGresult *res,
PGVerbosity verbosity, PGContextVisibility show_context)
{
const char *val;
const char *querytext = NULL;
int querypos = 0;
/* If we couldn't allocate a PGresult, just say "out of memory" */
if (res == NULL)
{
appendPQExpBuffer(msg, libpq_gettext("out of memory\n"));
return;
}
/*
* If we don't have any broken-down fields, just return the base message.
* This mainly applies if we're given a libpq-generated error result.
*/
if (res->errFields == NULL)
{
if (res->errMsg && res->errMsg[0])
appendPQExpBufferStr(msg, res->errMsg);
else
appendPQExpBuffer(msg, libpq_gettext("no error message available\n"));
return;
}
/* Else build error message from relevant fields */
val = PQresultErrorField(res, PG_DIAG_SEVERITY);
if (val)
appendPQExpBuffer(msg, "%s: ", val);
if (verbosity == PQERRORS_SQLSTATE)
{
/*
* If we have a SQLSTATE, print that and nothing else. If not (which
* shouldn't happen for server-generated errors, but might possibly
* happen for libpq-generated ones), fall back to TERSE format, as
* that seems better than printing nothing at all.
*/
val = PQresultErrorField(res, PG_DIAG_SQLSTATE);
if (val)
{
appendPQExpBuffer(msg, "%s\n", val);
return;
}
verbosity = PQERRORS_TERSE;
}
if (verbosity == PQERRORS_VERBOSE)
{
val = PQresultErrorField(res, PG_DIAG_SQLSTATE);
if (val)
appendPQExpBuffer(msg, "%s: ", val);
}
val = PQresultErrorField(res, PG_DIAG_MESSAGE_PRIMARY);
if (val)
appendPQExpBufferStr(msg, val);
val = PQresultErrorField(res, PG_DIAG_STATEMENT_POSITION);
if (val)
{
if (verbosity != PQERRORS_TERSE && res->errQuery != NULL)
{
/* emit position as a syntax cursor display */
querytext = res->errQuery;
querypos = atoi(val);
}
else
{
/* emit position as text addition to primary message */
/* translator: %s represents a digit string */
appendPQExpBuffer(msg, libpq_gettext(" at character %s"),
val);
}
}
else
{
val = PQresultErrorField(res, PG_DIAG_INTERNAL_POSITION);
if (val)
{
querytext = PQresultErrorField(res, PG_DIAG_INTERNAL_QUERY);
if (verbosity != PQERRORS_TERSE && querytext != NULL)
{
/* emit position as a syntax cursor display */
querypos = atoi(val);
}
else
{
/* emit position as text addition to primary message */
/* translator: %s represents a digit string */
appendPQExpBuffer(msg, libpq_gettext(" at character %s"),
val);
}
}
}
appendPQExpBufferChar(msg, '\n');
if (verbosity != PQERRORS_TERSE)
{
if (querytext && querypos > 0)
reportErrorPosition(msg, querytext, querypos,
res->client_encoding);
val = PQresultErrorField(res, PG_DIAG_MESSAGE_DETAIL);
if (val)
appendPQExpBuffer(msg, libpq_gettext("DETAIL: %s\n"), val);
val = PQresultErrorField(res, PG_DIAG_MESSAGE_HINT);
if (val)
appendPQExpBuffer(msg, libpq_gettext("HINT: %s\n"), val);
val = PQresultErrorField(res, PG_DIAG_INTERNAL_QUERY);
if (val)
appendPQExpBuffer(msg, libpq_gettext("QUERY: %s\n"), val);
if (show_context == PQSHOW_CONTEXT_ALWAYS ||
(show_context == PQSHOW_CONTEXT_ERRORS &&
res->resultStatus == PGRES_FATAL_ERROR))
{
val = PQresultErrorField(res, PG_DIAG_CONTEXT);
if (val)
appendPQExpBuffer(msg, libpq_gettext("CONTEXT: %s\n"),
val);
}
}
if (verbosity == PQERRORS_VERBOSE)
{
val = PQresultErrorField(res, PG_DIAG_SCHEMA_NAME);
if (val)
appendPQExpBuffer(msg,
libpq_gettext("SCHEMA NAME: %s\n"), val);
val = PQresultErrorField(res, PG_DIAG_TABLE_NAME);
if (val)
appendPQExpBuffer(msg,
libpq_gettext("TABLE NAME: %s\n"), val);
val = PQresultErrorField(res, PG_DIAG_COLUMN_NAME);
if (val)
appendPQExpBuffer(msg,
libpq_gettext("COLUMN NAME: %s\n"), val);
val = PQresultErrorField(res, PG_DIAG_DATATYPE_NAME);
if (val)
appendPQExpBuffer(msg,
libpq_gettext("DATATYPE NAME: %s\n"), val);
val = PQresultErrorField(res, PG_DIAG_CONSTRAINT_NAME);
if (val)
appendPQExpBuffer(msg,
libpq_gettext("CONSTRAINT NAME: %s\n"), val);
}
if (verbosity == PQERRORS_VERBOSE)
{
const char *valf;
const char *vall;
valf = PQresultErrorField(res, PG_DIAG_SOURCE_FILE);
vall = PQresultErrorField(res, PG_DIAG_SOURCE_LINE);
val = PQresultErrorField(res, PG_DIAG_SOURCE_FUNCTION);
if (val || valf || vall)
{
appendPQExpBufferStr(msg, libpq_gettext("LOCATION: "));
if (val)
appendPQExpBuffer(msg, libpq_gettext("%s, "), val);
if (valf && vall) /* unlikely we'd have just one */
appendPQExpBuffer(msg, libpq_gettext("%s:%s"),
valf, vall);
appendPQExpBufferChar(msg, '\n');
}
}
}
/*
* Add an error-location display to the error message under construction.
*
* The cursor location is measured in logical characters; the query string
* is presumed to be in the specified encoding.
*/
static void
reportErrorPosition(PQExpBuffer msg, const char *query, int loc, int encoding)
{
#define DISPLAY_SIZE 60 /* screen width limit, in screen cols */
#define MIN_RIGHT_CUT 10 /* try to keep this far away from EOL */
char *wquery;
int slen,
cno,
i,
*qidx,
*scridx,
qoffset,
scroffset,
ibeg,
iend,
loc_line;
bool mb_encoding,
beg_trunc,
end_trunc;
/* Convert loc from 1-based to 0-based; no-op if out of range */
loc--;
if (loc < 0)
return;
/* Need a writable copy of the query */
wquery = strdup(query);
if (wquery == NULL)
return; /* fail silently if out of memory */
/*
* Each character might occupy multiple physical bytes in the string, and
* in some Far Eastern character sets it might take more than one screen
* column as well. We compute the starting byte offset and starting
* screen column of each logical character, and store these in qidx[] and
* scridx[] respectively.
*/
/* we need a safe allocation size... */
slen = strlen(wquery) + 1;
qidx = (int *) malloc(slen * sizeof(int));
if (qidx == NULL)
{
free(wquery);
return;
}
scridx = (int *) malloc(slen * sizeof(int));
if (scridx == NULL)
{
free(qidx);
free(wquery);
return;
}
/* We can optimize a bit if it's a single-byte encoding */
mb_encoding = (pg_encoding_max_length(encoding) != 1);
/*
* Within the scanning loop, cno is the current character's logical
* number, qoffset is its offset in wquery, and scroffset is its starting
* logical screen column (all indexed from 0). "loc" is the logical
* character number of the error location. We scan to determine loc_line
* (the 1-based line number containing loc) and ibeg/iend (first character
* number and last+1 character number of the line containing loc). Note
* that qidx[] and scridx[] are filled only as far as iend.
*/
qoffset = 0;
scroffset = 0;
loc_line = 1;
ibeg = 0;
iend = -1; /* -1 means not set yet */
for (cno = 0; wquery[qoffset] != '\0'; cno++)
{
char ch = wquery[qoffset];
qidx[cno] = qoffset;
scridx[cno] = scroffset;
/*
* Replace tabs with spaces in the writable copy. (Later we might
* want to think about coping with their variable screen width, but
* not today.)
*/
if (ch == '\t')
wquery[qoffset] = ' ';
/*
* If end-of-line, count lines and mark positions. Each \r or \n
* counts as a line except when \r \n appear together.
*/
else if (ch == '\r' || ch == '\n')
{
if (cno < loc)
{
if (ch == '\r' ||
cno == 0 ||
wquery[qidx[cno - 1]] != '\r')
loc_line++;
/* extract beginning = last line start before loc. */
ibeg = cno + 1;
}
else
{
/* set extract end. */
iend = cno;
/* done scanning. */
break;
}
}
/* Advance */
if (mb_encoding)
{
int w;
w = pg_encoding_dsplen(encoding, &wquery[qoffset]);
/* treat any non-tab control chars as width 1 */
if (w <= 0)
w = 1;
scroffset += w;
qoffset += pg_encoding_mblen(encoding, &wquery[qoffset]);
}
else
{
/* We assume wide chars only exist in multibyte encodings */
scroffset++;
qoffset++;
}
}
/* Fix up if we didn't find an end-of-line after loc */
if (iend < 0)
{
iend = cno; /* query length in chars, +1 */
qidx[iend] = qoffset;
scridx[iend] = scroffset;
}
/* Print only if loc is within computed query length */
if (loc <= cno)
{
/* If the line extracted is too long, we truncate it. */
beg_trunc = false;
end_trunc = false;
if (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE)
{
/*
* We first truncate right if it is enough. This code might be
* off a space or so on enforcing MIN_RIGHT_CUT if there's a wide
* character right there, but that should be okay.
*/
if (scridx[ibeg] + DISPLAY_SIZE >= scridx[loc] + MIN_RIGHT_CUT)
{
while (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE)
iend--;
end_trunc = true;
}
else
{
/* Truncate right if not too close to loc. */
while (scridx[loc] + MIN_RIGHT_CUT < scridx[iend])
{
iend--;
end_trunc = true;
}
/* Truncate left if still too long. */
while (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE)
{
ibeg++;
beg_trunc = true;
}
}
}
/* truncate working copy at desired endpoint */
wquery[qidx[iend]] = '\0';
/* Begin building the finished message. */
i = msg->len;
appendPQExpBuffer(msg, libpq_gettext("LINE %d: "), loc_line);
if (beg_trunc)
appendPQExpBufferStr(msg, "...");
/*
* While we have the prefix in the msg buffer, compute its screen
* width.
*/
scroffset = 0;
for (; i < msg->len; i += pg_encoding_mblen(encoding, &msg->data[i]))
{
int w = pg_encoding_dsplen(encoding, &msg->data[i]);
if (w <= 0)
w = 1;
scroffset += w;
}
/* Finish up the LINE message line. */
appendPQExpBufferStr(msg, &wquery[qidx[ibeg]]);
if (end_trunc)
appendPQExpBufferStr(msg, "...");
appendPQExpBufferChar(msg, '\n');
/* Now emit the cursor marker line. */
scroffset += scridx[loc] - scridx[ibeg];
for (i = 0; i < scroffset; i++)
appendPQExpBufferChar(msg, ' ');
appendPQExpBufferChar(msg, '^');
appendPQExpBufferChar(msg, '\n');
}
/* Clean up. */
free(scridx);
free(qidx);
free(wquery);
}
/*
* Attempt to read a ParameterStatus message.
* This is possible in several places, so we break it out as a subroutine.
* Entry: 'S' message type and length have already been consumed.
* Exit: returns 0 if successfully consumed message.
* returns EOF if not enough data.
*/
static int
getParameterStatus(PGconn *conn)
{
PQExpBufferData valueBuf;
/* Get the parameter name */
if (pqGets(&conn->workBuffer, conn))
return EOF;
/* Get the parameter value (could be large) */
initPQExpBuffer(&valueBuf);
if (pqGets(&valueBuf, conn))
{
termPQExpBuffer(&valueBuf);
return EOF;
}
/* And save it */
pqSaveParameterStatus(conn, conn->workBuffer.data, valueBuf.data);
termPQExpBuffer(&valueBuf);
return 0;
}
/*
* Attempt to read a Notify response message.
* This is possible in several places, so we break it out as a subroutine.
* Entry: 'A' message type and length have already been consumed.
* Exit: returns 0 if successfully consumed Notify message.
* returns EOF if not enough data.
*/
static int
getNotify(PGconn *conn)
{
int be_pid;
char *svname;
int nmlen;
int extralen;
PGnotify *newNotify;
if (pqGetInt(&be_pid, 4, conn))
return EOF;
if (pqGets(&conn->workBuffer, conn))
return EOF;
/* must save name while getting extra string */
svname = strdup(conn->workBuffer.data);
if (!svname)
return EOF;
if (pqGets(&conn->workBuffer, conn))
{
free(svname);
return EOF;
}
/*
* Store the strings right after the PQnotify structure so it can all be
* freed at once. We don't use NAMEDATALEN because we don't want to tie
* this interface to a specific server name length.
*/
nmlen = strlen(svname);
extralen = strlen(conn->workBuffer.data);
newNotify = (PGnotify *) malloc(sizeof(PGnotify) + nmlen + extralen + 2);
if (newNotify)
{
newNotify->relname = (char *) newNotify + sizeof(PGnotify);
strcpy(newNotify->relname, svname);
newNotify->extra = newNotify->relname + nmlen + 1;
strcpy(newNotify->extra, conn->workBuffer.data);
newNotify->be_pid = be_pid;
newNotify->next = NULL;
if (conn->notifyTail)
conn->notifyTail->next = newNotify;
else
conn->notifyHead = newNotify;
conn->notifyTail = newNotify;
}
free(svname);
return 0;
}
/*
* getCopyStart - process CopyInResponse, CopyOutResponse or
* CopyBothResponse message
*
* parseInput already read the message type and length.
*/
static int
getCopyStart(PGconn *conn, ExecStatusType copytype)
{
PGresult *result;
int nfields;
int i;
result = PQmakeEmptyPGresult(conn, copytype);
if (!result)
goto failure;
if (pqGetc(&conn->copy_is_binary, conn))
goto failure;
result->binary = conn->copy_is_binary;
/* the next two bytes are the number of fields */
if (pqGetInt(&(result->numAttributes), 2, conn))
goto failure;
nfields = result->numAttributes;
/* allocate space for the attribute descriptors */
if (nfields > 0)
{
result->attDescs = (PGresAttDesc *)
pqResultAlloc(result, nfields * sizeof(PGresAttDesc), true);
if (!result->attDescs)
goto failure;
MemSet(result->attDescs, 0, nfields * sizeof(PGresAttDesc));
}
for (i = 0; i < nfields; i++)
{
int format;
if (pqGetInt(&format, 2, conn))
goto failure;
/*
* Since pqGetInt treats 2-byte integers as unsigned, we need to
* coerce these results to signed form.
*/
format = (int) ((int16) format);
result->attDescs[i].format = format;
}
/* Success! */
conn->result = result;
return 0;
failure:
PQclear(result);
return EOF;
}
/*
* getReadyForQuery - process ReadyForQuery message
*/
static int
getReadyForQuery(PGconn *conn)
{
char xact_status;
if (pqGetc(&xact_status, conn))
return EOF;
switch (xact_status)
{
case 'I':
conn->xactStatus = PQTRANS_IDLE;
break;
case 'T':
conn->xactStatus = PQTRANS_INTRANS;
break;
case 'E':
conn->xactStatus = PQTRANS_INERROR;
break;
default:
conn->xactStatus = PQTRANS_UNKNOWN;
break;
}
return 0;
}
/*
* saveCdbStatMsg - attach qExec statistics message to PGresult
*/
void
saveCdbStatMsg(PGresult *result, char *data, int len)
{
pgCdbStatCell *cell;
/* Allocate list element. */
cell = pqResultAlloc(result, sizeof(*cell), true);
if (!cell)
return;
/* Allocate an aligned buffer from the PGresult's memory pool. */
cell->data = (char *)pqResultAlloc(result, len, true);
if (!cell->data)
return;
/* Copy the message data. */
cell->len = len;
memcpy(cell->data, data, len);
/* Add to head of list. */
cell->next = result->cdbstats;
result->cdbstats = cell;
return;
} /* saveCdbStatMsg */
/*
* getCopyDataMessage - fetch next CopyData message, process async messages
*
* Returns length word of CopyData message (> 0), or 0 if no complete
* message available, -1 if end of copy, -2 if error.
*/
static int
getCopyDataMessage(PGconn *conn)
{
char id;
int msgLength;
int avail;
for (;;)
{
/*
* Do we have the next input message? To make life simpler for async
* callers, we keep returning 0 until the next message is fully
* available, even if it is not Copy Data.
*/
conn->inCursor = conn->inStart;
if (pqGetc(&id, conn))
return 0;
if (pqGetInt(&msgLength, 4, conn))
return 0;
if (msgLength < 4)
{
handleSyncLoss(conn, id, msgLength);
return -2;
}
avail = conn->inEnd - conn->inCursor;
if (avail < msgLength - 4)
{
/*
* Before returning, enlarge the input buffer if needed to hold
* the whole message. See notes in parseInput.
*/
if (pqCheckInBufferSpace(conn->inCursor + (size_t) msgLength - 4,
conn))
{
/*
* XXX add some better recovery code... plan is to skip over
* the message using its length, then report an error. For the
* moment, just treat this like loss of sync (which indeed it
* might be!)
*/
handleSyncLoss(conn, id, msgLength);
return -2;
}
return 0;
}
/*
* If it's a legitimate async message type, process it. (NOTIFY
* messages are not currently possible here, but we handle them for
* completeness.) Otherwise, if it's anything except Copy Data,
* report end-of-copy.
*/
switch (id)
{
case 'A': /* NOTIFY */
if (getNotify(conn))
return 0;
break;
case 'N': /* NOTICE */
if (pqGetErrorNotice3(conn, false))
return 0;
break;
case 'S': /* ParameterStatus */
if (getParameterStatus(conn))
return 0;
break;
case 'd': /* Copy Data, pass it back to caller */
return msgLength;
case 'c':
/*
* If this is a CopyDone message, exit COPY_OUT mode and let
* caller read status with PQgetResult(). If we're in
* COPY_BOTH mode, return to COPY_IN mode.
*/
if (conn->asyncStatus == PGASYNC_COPY_BOTH)
conn->asyncStatus = PGASYNC_COPY_IN;
else
conn->asyncStatus = PGASYNC_BUSY;
return -1;
default: /* treat as end of copy */
/*
* Any other message terminates either COPY_IN or COPY_BOTH
* mode.
*/
conn->asyncStatus = PGASYNC_BUSY;
return -1;
}
/* Drop the processed message and loop around for another */
conn->inStart = conn->inCursor;
}
}
/*
* PQgetCopyData - read a row of data from the backend during COPY OUT
* or COPY BOTH
*
* If successful, sets *buffer to point to a malloc'd row of data, and
* returns row length (always > 0) as result.
* Returns 0 if no row available yet (only possible if async is true),
* -1 if end of copy (consult PQgetResult), or -2 if error (consult
* PQerrorMessage).
*/
int
pqGetCopyData3(PGconn *conn, char **buffer, int async)
{
int msgLength;
for (;;)
{
/*
* Collect the next input message. To make life simpler for async
* callers, we keep returning 0 until the next message is fully
* available, even if it is not Copy Data.
*/
msgLength = getCopyDataMessage(conn);
if (msgLength < 0)
return msgLength; /* end-of-copy or error */
if (msgLength == 0)
{
/* Don't block if async read requested */
if (async)
return 0;
/* Need to load more data */
if (pqWait(true, false, conn) ||
pqReadData(conn) < 0)
return -2;
continue;
}
/*
* Drop zero-length messages (shouldn't happen anyway). Otherwise
* pass the data back to the caller.
*/
msgLength -= 4;
if (msgLength > 0)
{
*buffer = (char *) malloc(msgLength + 1);
if (*buffer == NULL)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("out of memory\n"));
return -2;
}
memcpy(*buffer, &conn->inBuffer[conn->inCursor], msgLength);
(*buffer)[msgLength] = '\0'; /* Add terminating null */
/* Mark message consumed */
conn->inStart = conn->inCursor + msgLength;
return msgLength;
}
/* Empty, so drop it and loop around for another */
conn->inStart = conn->inCursor;
}
}
/*
* PQgetline - gets a newline-terminated string from the backend.
*
* See fe-exec.c for documentation.
*/
int
pqGetline3(PGconn *conn, char *s, int maxlen)
{
int status;
if (conn->sock == PGINVALID_SOCKET ||
(conn->asyncStatus != PGASYNC_COPY_OUT &&
conn->asyncStatus != PGASYNC_COPY_BOTH) ||
conn->copy_is_binary)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("PQgetline: not doing text COPY OUT\n"));
*s = '\0';
return EOF;
}
while ((status = PQgetlineAsync(conn, s, maxlen - 1)) == 0)
{
/* need to load more data */
if (pqWait(true, false, conn) ||
pqReadData(conn) < 0)
{
*s = '\0';
return EOF;
}
}
if (status < 0)
{
/* End of copy detected; gin up old-style terminator */
strcpy(s, "\\.");
return 0;
}
/* Add null terminator, and strip trailing \n if present */
if (s[status - 1] == '\n')
{
s[status - 1] = '\0';
return 0;
}
else
{
s[status] = '\0';
return 1;
}
}
/*
* PQgetlineAsync - gets a COPY data row without blocking.
*
* See fe-exec.c for documentation.
*/
int
pqGetlineAsync3(PGconn *conn, char *buffer, int bufsize)
{
int msgLength;
int avail;
if (conn->asyncStatus != PGASYNC_COPY_OUT
&& conn->asyncStatus != PGASYNC_COPY_BOTH)
return -1; /* we are not doing a copy... */
/*
* Recognize the next input message. To make life simpler for async
* callers, we keep returning 0 until the next message is fully available
* even if it is not Copy Data. This should keep PQendcopy from blocking.
* (Note: unlike pqGetCopyData3, we do not change asyncStatus here.)
*/
msgLength = getCopyDataMessage(conn);
if (msgLength < 0)
return -1; /* end-of-copy or error */
if (msgLength == 0)
return 0; /* no data yet */
/*
* Move data from libpq's buffer to the caller's. In the case where a
* prior call found the caller's buffer too small, we use
* conn->copy_already_done to remember how much of the row was already
* returned to the caller.
*/
conn->inCursor += conn->copy_already_done;
avail = msgLength - 4 - conn->copy_already_done;
if (avail <= bufsize)
{
/* Able to consume the whole message */
memcpy(buffer, &conn->inBuffer[conn->inCursor], avail);
/* Mark message consumed */
conn->inStart = conn->inCursor + avail;
/* Reset state for next time */
conn->copy_already_done = 0;
return avail;
}
else
{
/* We must return a partial message */
memcpy(buffer, &conn->inBuffer[conn->inCursor], bufsize);
/* The message is NOT consumed from libpq's buffer */
conn->copy_already_done += bufsize;
return bufsize;
}
}
/*
* PQendcopy
*
* See fe-exec.c for documentation.
*/
int
pqEndcopy3(PGconn *conn)
{
PGresult *result;
if (conn->asyncStatus != PGASYNC_COPY_IN &&
conn->asyncStatus != PGASYNC_COPY_OUT &&
conn->asyncStatus != PGASYNC_COPY_BOTH)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("no COPY in progress\n"));
return 1;
}
/* Send the CopyDone message if needed */
if (conn->asyncStatus == PGASYNC_COPY_IN ||
conn->asyncStatus == PGASYNC_COPY_BOTH)
{
if (pqPutMsgStart('c', false, conn) < 0 ||
pqPutMsgEnd(conn) < 0)
return 1;
/*
* If we sent the COPY command in extended-query mode, we must issue a
* Sync as well.
*/
if (conn->queryclass != PGQUERY_SIMPLE)
{
if (pqPutMsgStart('S', false, conn) < 0 ||
pqPutMsgEnd(conn) < 0)
return 1;
}
}
/*
* make sure no data is waiting to be sent, abort if we are non-blocking
* and the flush fails
*/
if (pqFlush(conn) && pqIsnonblocking(conn))
return 1;
/* Return to active duty */
conn->asyncStatus = PGASYNC_BUSY;
resetPQExpBuffer(&conn->errorMessage);
/*
* Non blocking connections may have to abort at this point. If everyone
* played the game there should be no problem, but in error scenarios the
* expected messages may not have arrived yet. (We are assuming that the
* backend's packetizing will ensure that CommandComplete arrives along
* with the CopyDone; are there corner cases where that doesn't happen?)
*/
if (pqIsnonblocking(conn) && PQisBusy(conn))
return 1;
/* Wait for the completion response */
result = PQgetResult(conn);
/* Expecting a successful result */
if (result && result->resultStatus == PGRES_COMMAND_OK)
{
PQclear(result);
return 0;
}
/*
* Trouble. For backwards-compatibility reasons, we issue the error
* message as if it were a notice (would be nice to get rid of this
* silliness, but too many apps probably don't handle errors from
* PQendcopy reasonably). Note that the app can still obtain the error
* status from the PGconn object.
*/
if (conn->errorMessage.len > 0)
{
/* We have to strip the trailing newline ... pain in neck... */
char svLast = conn->errorMessage.data[conn->errorMessage.len - 1];
if (svLast == '\n')
conn->errorMessage.data[conn->errorMessage.len - 1] = '\0';
pqInternalNotice(&conn->noticeHooks, "%s", conn->errorMessage.data);
conn->errorMessage.data[conn->errorMessage.len - 1] = svLast;
}
PQclear(result);
return 1;
}
/*
* PQfn - Send a function call to the POSTGRES backend.
*
* See fe-exec.c for documentation.
*/
PGresult *
pqFunctionCall3(PGconn *conn, Oid fnid,
int *result_buf, int *actual_result_len,
int result_is_int,
const PQArgBlock *args, int nargs)
{
bool needInput = false;
ExecStatusType status = PGRES_FATAL_ERROR;
char id;
int msgLength;
int avail;
int i;
/* PQfn already validated connection state */
if (pqPutMsgStart('F', false, conn) < 0 || /* function call msg */
pqPutInt(fnid, 4, conn) < 0 || /* function id */
pqPutInt(1, 2, conn) < 0 || /* # of format codes */
pqPutInt(1, 2, conn) < 0 || /* format code: BINARY */
pqPutInt(nargs, 2, conn) < 0) /* # of args */
{
/* error message should be set up already */
return NULL;
}
for (i = 0; i < nargs; ++i)
{ /* len.int4 + contents */
if (pqPutInt(args[i].len, 4, conn))
return NULL;
if (args[i].len == -1)
continue; /* it's NULL */
if (args[i].isint)
{
if (pqPutInt(args[i].u.integer, args[i].len, conn))
return NULL;
}
else
{
if (pqPutnchar((char *) args[i].u.ptr, args[i].len, conn))
return NULL;
}
}
if (pqPutInt(1, 2, conn) < 0) /* result format code: BINARY */
return NULL;
if (pqPutMsgEnd(conn) < 0 ||
pqFlush(conn))
return NULL;
for (;;)
{
if (needInput)
{
/* Wait for some data to arrive (or for the channel to close) */
if (pqWait(true, false, conn) ||
pqReadData(conn) < 0)
break;
}
/*
* Scan the message. If we run out of data, loop around to try again.
*/
needInput = true;
conn->inCursor = conn->inStart;
if (pqGetc(&id, conn))
continue;
if (pqGetInt(&msgLength, 4, conn))
continue;
/*
* Try to validate message type/length here. A length less than 4 is
* definitely broken. Large lengths should only be believed for a few
* message types.
*/
if (msgLength < 4)
{
handleSyncLoss(conn, id, msgLength);
break;
}
if (msgLength > 30000 && !VALID_LONG_MESSAGE_TYPE(id))
{
handleSyncLoss(conn, id, msgLength);
break;
}
/*
* Can't process if message body isn't all here yet.
*/
msgLength -= 4;
avail = conn->inEnd - conn->inCursor;
if (avail < msgLength)
{
/*
* Before looping, enlarge the input buffer if needed to hold the
* whole message. See notes in parseInput.
*/
if (pqCheckInBufferSpace(conn->inCursor + (size_t) msgLength,
conn))
{
/*
* XXX add some better recovery code... plan is to skip over
* the message using its length, then report an error. For the
* moment, just treat this like loss of sync (which indeed it
* might be!)
*/
handleSyncLoss(conn, id, msgLength);
break;
}
continue;
}
/*
* We should see V or E response to the command, but might get N
* and/or A notices first. We also need to swallow the final Z before
* returning.
*/
switch (id)
{
case 'V': /* function result */
if (pqGetInt(actual_result_len, 4, conn))
continue;
if (*actual_result_len != -1)
{
if (result_is_int)
{
if (pqGetInt(result_buf, *actual_result_len, conn))
continue;
}
else
{
if (pqGetnchar((char *) result_buf,
*actual_result_len,
conn))
continue;
}
}
/* correctly finished function result message */
status = PGRES_COMMAND_OK;
break;
case 'E': /* error return */
if (pqGetErrorNotice3(conn, true))
continue;
status = PGRES_FATAL_ERROR;
break;
case 'A': /* notify message */
/* handle notify and go back to processing return values */
if (getNotify(conn))
continue;
break;
case 'N': /* notice */
/* handle notice and go back to processing return values */
if (pqGetErrorNotice3(conn, false))
continue;
break;
case 'Z': /* backend is ready for new query */
if (getReadyForQuery(conn))
continue;
/* consume the message and exit */
conn->inStart += 5 + msgLength;
/* if we saved a result object (probably an error), use it */
if (conn->result)
return pqPrepareAsyncResult(conn);
return PQmakeEmptyPGresult(conn, status);
case 'S': /* parameter status */
if (getParameterStatus(conn))
continue;
break;
default:
/* The backend violates the protocol. */
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("protocol error: id=0x%x\n"),
id);
pqSaveErrorResult(conn);
/* trust the specified message length as what to skip */
conn->inStart += 5 + msgLength;
return pqPrepareAsyncResult(conn);
}
/* Completed this message, keep going */
/* trust the specified message length as what to skip */
conn->inStart += 5 + msgLength;
needInput = false;
}
/*
* We fall out of the loop only upon failing to read data.
* conn->errorMessage has been set by pqWait or pqReadData. We want to
* append it to any already-received error message.
*/
pqSaveErrorResult(conn);
return pqPrepareAsyncResult(conn);
}
/*
* Construct startup packet
*
* Returns a malloc'd packet buffer, or NULL if out of memory
*/
char *
pqBuildStartupPacket3(PGconn *conn, int *packetlen,
const PQEnvironmentOption *options)
{
char *startpacket;
*packetlen = build_startup_packet(conn, NULL, options);
startpacket = (char *) malloc(*packetlen);
if (!startpacket)
return NULL;
*packetlen = build_startup_packet(conn, startpacket, options);
return startpacket;
}
/*
* Build a startup packet given a filled-in PGconn structure.
*
* We need to figure out how much space is needed, then fill it in.
* To avoid duplicate logic, this routine is called twice: the first time
* (with packet == NULL) just counts the space needed, the second time
* (with packet == allocated space) fills it in. Return value is the number
* of bytes used.
*/
static int
build_startup_packet(const PGconn *conn, char *packet,
const PQEnvironmentOption *options)
{
int packet_len = 0;
const PQEnvironmentOption *next_eo;
const char *val;
/* Protocol version comes first. */
if (packet)
{
ProtocolVersion pv = pg_hton32(conn->pversion);
memcpy(packet + packet_len, &pv, sizeof(ProtocolVersion));
}
packet_len += sizeof(ProtocolVersion);
/* Add user name, database name, options */
#define ADD_STARTUP_OPTION(optname, optval) \
do { \
if (packet) \
strcpy(packet + packet_len, optname); \
packet_len += strlen(optname) + 1; \
if (packet) \
strcpy(packet + packet_len, optval); \
packet_len += strlen(optval) + 1; \
} while(0)
if (conn->pguser && conn->pguser[0])
ADD_STARTUP_OPTION("user", conn->pguser);
if (conn->dbName && conn->dbName[0])
ADD_STARTUP_OPTION("database", conn->dbName);
if (conn->replication && conn->replication[0])
ADD_STARTUP_OPTION("replication", conn->replication);
/*
* We don't have an real pg_compatible option, it just
* affects the version number.
*/
if (conn->gpconntype && conn->gpconntype[0]
&& strcmp(conn->gpconntype, GPCONN_TYPE_DEFAULT) != 0)
ADD_STARTUP_OPTION(GPCONN_TYPE, conn->gpconntype);
if (conn->pgoptions && conn->pgoptions[0])
ADD_STARTUP_OPTION("options", conn->pgoptions);
if (conn->diffoptions && conn->diffoptions[0])
ADD_STARTUP_OPTION("diff_options", conn->diffoptions);
if (conn->send_appname)
{
/* Use appname if present, otherwise use fallback */
val = conn->appname ? conn->appname : conn->fbappname;
if (val && val[0])
ADD_STARTUP_OPTION("application_name", val);
}
if (conn->client_encoding_initial && conn->client_encoding_initial[0])
ADD_STARTUP_OPTION("client_encoding", conn->client_encoding_initial);
/* CDB: Add qExec startup data */
if (conn->gpqeid && conn->gpqeid[0])
ADD_STARTUP_OPTION("gpqeid", conn->gpqeid);
/* Add any environment-driven GUC settings needed */
for (next_eo = options; next_eo->envName; next_eo++)
{
if ((val = getenv(next_eo->envName)) != NULL)
{
if (pg_strcasecmp(val, "default") != 0)
ADD_STARTUP_OPTION(next_eo->pgName, val);
}
}
/* Add trailing terminator */
if (packet)
packet[packet_len] = '\0';
packet_len++;
return packet_len;
}
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