/*
* getCopyStart - process CopyInResponse or CopyOutResponse 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;
}
/*
* 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)
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. NOTICE is definitely possible, and ParameterStatus
* could probably be made to happen.) 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;
default: /* treat as end of copy */
return -1;
}
/* Drop the processed message and loop around for another */
conn->inStart = conn->inCursor;
}
}
/*
* 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.
*
* 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)
{
PGresult *result;
int nparams;
int i;
result = PQmakeEmptyPGresult(conn, PGRES_COMMAND_OK);
if (!result)
goto failure;
/* 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 failure;
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 failure;
MemSet(result->paramDescs, 0, nparams * sizeof(PGresParamDesc));
}
/* get parameter info */
for (i = 0; i < nparams; i++)
{
int typid;
if (pqGetInt(&typid, 4, conn))
goto failure;
result->paramDescs[i].typid = typid;
}
/* Success! */
conn->result = result;
return 0;
failure:
PQclear(result);
return EOF;
}
/*
* 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;
}
/*
* 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;
int nmlen;
PGnotify *newNotify;
if (pqGetInt(&be_pid, 4, conn))
return EOF;
if (pqGets(&conn->workBuffer, conn))
return EOF;
/*
* Store the relation name 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(conn->workBuffer.data);
newNotify = (PGnotify *) malloc(sizeof(PGnotify) + nmlen + 1);
if (newNotify)
{
newNotify->relname = (char *) newNotify + sizeof(PGnotify);
strcpy(newNotify->relname, conn->workBuffer.data);
/* fake up an empty-string extra field */
newNotify->extra = newNotify->relname + nmlen;
newNotify->be_pid = be_pid;
newNotify->next = NULL;
if (conn->notifyTail)
conn->notifyTail->next = newNotify;
else
conn->notifyHead = newNotify;
conn->notifyTail = newNotify;
}
return 0;
}
/*
* parseInput subroutine to read a 'B' or 'D' (row data) message.
* We fill rowbuf with column pointers and then call the row processor.
* Returns: 0 if completed message, EOF if error or not enough data
* received yet.
*
* Note that if we run out of data, we have to suspend and reprocess
* the message after more data is received. Otherwise, conn->inStart
* must get advanced past the processed data.
*/
static int
getAnotherTuple(PGconn *conn, bool binary)
{
PGresult *result = conn->result;
int nfields = result->numAttributes;
const char *errmsg;
PGdataValue *rowbuf;
/* the backend sends us a bitmap of which attributes are null */
char std_bitmap[64]; /* used unless it doesn't fit */
char *bitmap = std_bitmap;
int i;
size_t nbytes; /* the number of bytes in bitmap */
char bmap; /* One byte of the bitmap */
int bitmap_index; /* Its index */
int bitcnt; /* number of bits examined in current byte */
int vlen; /* length of the current field value */
/* 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;
}
/* Save format specifier */
result->binary = binary;
/*
* If it's binary, fix the column format indicators. We assume the
* backend will consistently send either B or D, not a mix.
*/
if (binary)
{
for (i = 0; i < nfields; i++)
result->attDescs[i].format = 1;
}
/* Get the null-value bitmap */
nbytes = (nfields + BITS_PER_BYTE - 1) / BITS_PER_BYTE;
/* malloc() only for unusually large field counts... */
if (nbytes > sizeof(std_bitmap))
{
bitmap = (char *) malloc(nbytes);
if (!bitmap)
{
errmsg = NULL; /* means "out of memory", see below */
goto advance_and_error;
}
}
if (pqGetnchar(bitmap, nbytes, conn))
goto EOFexit;
/* Scan the fields */
bitmap_index = 0;
bmap = bitmap[bitmap_index];
bitcnt = 0;
for (i = 0; i < nfields; i++)
{
/* get the value length */
if (!(bmap & 0200))
vlen = NULL_LEN;
else if (pqGetInt(&vlen, 4, conn))
goto EOFexit;
else
{
if (!binary)
vlen = vlen - 4;
if (vlen < 0)
vlen = 0;
}
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))
goto EOFexit;
}
/* advance the bitmap stuff */
bitcnt++;
if (bitcnt == BITS_PER_BYTE)
{
bitmap_index++;
bmap = bitmap[bitmap_index];
bitcnt = 0;
}
else
bmap <<= 1;
}
/* Release bitmap now if we allocated it */
if (bitmap != std_bitmap)
free(bitmap);
bitmap = NULL;
/* 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. Unfortunately we don't know for sure where
* the end is, so just throw away everything in the input buffer. This is
* not very desirable but it's the best we can do in protocol v2.
*/
conn->inStart = conn->inEnd;
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);
/*
* XXX: if PQmakeEmptyPGresult() fails, there's probably not much we can
* do to recover...
*/
conn->result = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
conn->asyncStatus = PGASYNC_READY;
EOFexit:
if (bitmap != NULL && bitmap != std_bitmap)
free(bitmap);
return EOF;
}
/*
* parseInput subroutine to read a 'T' (row descriptions) message.
* We build a PGresult structure containing the attribute data.
* Returns: 0 if completed message, EOF if error or not enough data
* received yet.
*
* Note that if we run out of data, we have to suspend and reprocess
* the message after more data is received. Otherwise, conn->inStart
* must get advanced past the processed data.
*/
static int
getRowDescriptions(PGconn *conn)
{
PGresult *result;
int nfields;
const char *errmsg;
int i;
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. */
/* the next two bytes are the number of fields */
if (pqGetInt(&(result->numAttributes), 2, conn))
goto EOFexit;
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));
}
/* get type info */
for (i = 0; i < nfields; i++)
{
int typid;
int typlen;
int atttypmod;
if (pqGets(&conn->workBuffer, conn) ||
pqGetInt(&typid, 4, conn) ||
pqGetInt(&typlen, 2, conn) ||
pqGetInt(&atttypmod, 4, conn))
goto EOFexit;
/*
* Since pqGetInt treats 2-byte integers as unsigned, we need to
* coerce the result to signed form.
*/
typlen = (int) ((int16) typlen);
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 = 0;
result->attDescs[i].columnid = 0;
result->attDescs[i].format = 0;
result->attDescs[i].typid = typid;
result->attDescs[i].typlen = typlen;
result->attDescs[i].atttypmod = atttypmod;
}
/* Success! */
conn->result = result;
/* Advance inStart to show that the "T" message has been processed. */
conn->inStart = conn->inCursor;
/*
* 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 the failed message. Unfortunately we don't know for sure where
* the end is, so just throw away everything in the input buffer. This is
* not very desirable but it's the best we can do in protocol v2.
*/
conn->inStart = conn->inEnd;
/*
* 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);
/*
* XXX: if PQmakeEmptyPGresult() fails, there's probably not much we can
* do to recover...
*/
conn->result = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
conn->asyncStatus = PGASYNC_READY;
EOFexit:
if (result && result != conn->result)
PQclear(result);
return EOF;
}
/*
* 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
pqParseInput2(PGconn *conn)
{
char id;
/*
* Loop to parse successive complete messages available in the buffer.
*/
for (;;)
{
/*
* Quit if in COPY_OUT state: we expect raw data from the server until
* PQendcopy is called. Don't try to parse it according to the normal
* protocol. (This is bogus. The data lines ought to be part of the
* protocol and have identifying leading characters.)
*/
if (conn->asyncStatus == PGASYNC_COPY_OUT)
return;
/*
* OK to try to read a message type code.
*/
conn->inCursor = conn->inStart;
if (pqGetc(&id, conn))
return;
/*
* NOTIFY and NOTICE messages can happen in any state besides COPY
* OUT; 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.
*/
if (id == 'A')
{
if (getNotify(conn))
return;
}
else if (id == 'N')
{
if (pqGetErrorNotice2(conn, false))
return;
}
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 displayed using the notice processor;
* 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 (pqGetErrorNotice2(conn, false /* treat as notice */ ))
return;
}
else
{
pqInternalNotice(&conn->noticeHooks,
"message type 0x%02x arrived from server while idle",
id);
/* Discard the unexpected message; good idea?? */
conn->inStart = conn->inEnd;
break;
}
}
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);
}
checkXactStatus(conn, conn->workBuffer.data);
conn->asyncStatus = PGASYNC_READY;
break;
case 'E': /* error return */
if (pqGetErrorNotice2(conn, true))
return;
conn->asyncStatus = PGASYNC_READY;
break;
case 'Z': /* backend is ready for new query */
conn->asyncStatus = PGASYNC_IDLE;
break;
case 'I': /* empty query */
/* read and throw away the closing '\0' */
if (pqGetc(&id, conn))
return;
if (id != '\0')
pqInternalNotice(&conn->noticeHooks,
"unexpected character %c following empty query response (\"I\" message)",
id);
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 '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 'P': /* synchronous (normal) portal */
if (pqGets(&conn->workBuffer, conn))
return;
/* We pretty much ignore this message type... */
break;
case 'T': /* row descriptions (start of query results) */
if (conn->result == NULL)
{
/* First 'T' in a query sequence */
if (getRowDescriptions(conn))
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 'D': /* ASCII data tuple */
if (conn->result != NULL)
{
/* Read another tuple of a normal query response */
if (getAnotherTuple(conn, FALSE))
return;
/* getAnotherTuple() moves inStart itself */
continue;
}
else
{
pqInternalNotice(&conn->noticeHooks,
"server sent data (\"D\" message) without prior row description (\"T\" message)");
/* Discard the unexpected message; good idea?? */
conn->inStart = conn->inEnd;
return;
}
break;
case 'B': /* Binary data tuple */
if (conn->result != NULL)
{
/* Read another tuple of a normal query response */
if (getAnotherTuple(conn, TRUE))
return;
/* getAnotherTuple() moves inStart itself */
continue;
}
else
{
pqInternalNotice(&conn->noticeHooks,
"server sent binary data (\"B\" message) without prior row description (\"T\" message)");
/* Discard the unexpected message; good idea?? */
conn->inStart = conn->inEnd;
return;
}
break;
case 'G': /* Start Copy In */
conn->asyncStatus = PGASYNC_COPY_IN;
break;
case 'H': /* Start Copy Out */
conn->asyncStatus = PGASYNC_COPY_OUT;
break;
/*
* Don't need to process CopyBothResponse here because it
* never arrives from the server during protocol 2.0.
*/
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);
/* Discard the unexpected message; good idea?? */
conn->inStart = conn->inEnd;
conn->asyncStatus = PGASYNC_READY;
return;
} /* switch on protocol character */
}
/* Successfully consumed this message */
conn->inStart = conn->inCursor;
}
}
/*
* PQfn - Send a function call to the POSTGRES backend.
*
* See fe-exec.c for documentation.
*/
PGresult *
pqFunctionCall2(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 i;
/* PQfn already validated connection state */
if (pqPutMsgStart('F', false, conn) < 0 || /* function call msg */
pqPuts(" ", conn) < 0 || /* dummy string */
pqPutInt(fnid, 4, conn) != 0 || /* function id */
pqPutInt(nargs, 4, conn) != 0) /* # of args */
{
pqHandleSendFailure(conn);
return NULL;
}
for (i = 0; i < nargs; ++i)
{ /* len.int4 + contents */
if (pqPutInt(args[i].len, 4, conn))
{
pqHandleSendFailure(conn);
return NULL;
}
if (args[i].isint)
{
if (pqPutInt(args[i].u.integer, 4, conn))
{
pqHandleSendFailure(conn);
return NULL;
}
}
else
{
if (pqPutnchar((char *) args[i].u.ptr, args[i].len, conn))
{
pqHandleSendFailure(conn);
return NULL;
}
}
}
if (pqPutMsgEnd(conn) < 0 ||
pqFlush(conn))
{
pqHandleSendFailure(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.
*/
conn->inCursor = conn->inStart;
needInput = true;
if (pqGetc(&id, conn))
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 (pqGetc(&id, conn))
continue;
if (id == 'G')
{
/* function returned nonempty value */
if (pqGetInt(actual_result_len, 4, conn))
continue;
if (result_is_int)
{
if (pqGetInt(result_buf, 4, conn))
continue;
}
else
{
if (pqGetnchar((char *) result_buf,
*actual_result_len,
conn))
continue;
}
if (pqGetc(&id, conn)) /* get the last '0' */
continue;
}
if (id == '0')
{
/* correctly finished function result message */
status = PGRES_COMMAND_OK;
}
else
{
/* The backend violates the protocol. */
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("protocol error: id=0x%x\n"),
id);
pqSaveErrorResult(conn);
conn->inStart = conn->inCursor;
return pqPrepareAsyncResult(conn);
}
break;
case 'E': /* error return */
if (pqGetErrorNotice2(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 (pqGetErrorNotice2(conn, false))
continue;
break;
case 'Z': /* backend is ready for new query */
/* consume the message and exit */
conn->inStart = conn->inCursor;
/* if we saved a result object (probably an error), use it */
if (conn->result)
return pqPrepareAsyncResult(conn);
return PQmakeEmptyPGresult(conn, status);
default:
/* The backend violates the protocol. */
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("protocol error: id=0x%x\n"),
id);
pqSaveErrorResult(conn);
conn->inStart = conn->inCursor;
return pqPrepareAsyncResult(conn);
}
/* Completed this message, keep going */
conn->inStart = conn->inCursor;
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);
}
/*
* 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;
/*
* 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 + 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;
}
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 displayed 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)
return;
}
strncpy(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)
return;
}
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)
return;
}
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->queryclass == PGQUERY_DESCRIBE)
{
/* First 'T' in a query sequence */
if (getRowDescriptions(conn))
return;
/*
* If we're doing a Describe, we're ready to pass the
* result back to the client.
*/
if (conn->queryclass == PGQUERY_DESCRIBE)
conn->asyncStatus = PGASYNC_READY;
}
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. Set up a COMMAND_OK
* result, instead of TUPLES_OK.
*/
if (conn->result == NULL)
conn->result = PQmakeEmptyPGresult(conn,
PGRES_COMMAND_OK);
/*
* If we're doing a Describe, we're ready to pass the
* result back to the client.
*/
if (conn->queryclass == PGQUERY_DESCRIBE)
conn->asyncStatus = PGASYNC_READY;
break;
case 't': /* Parameter Description */
if (getParamDescriptions(conn))
return;
break;
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;
}
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 '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;
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;
}
}
}
/*
* parseInput subroutine to read a 'D' (row data) message.
* We add another tuple to the existing PGresult structure.
* Returns: 0 if completed message, EOF if error or not enough data yet.
*
* Note that if we run out of data, we have to suspend and reprocess
* the message after more data is received. We keep a partially constructed
* tuple in conn->curTuple, and avoid reallocating already-allocated storage.
*/
static int
getAnotherTuple(PGconn *conn, int msgLength)
{
PGresult *result = conn->result;
int nfields = result->numAttributes;
PGresAttValue *tup;
int tupnfields; /* # fields from tuple */
int vlen; /* length of the current field value */
int i;
/* Allocate tuple space if first time for this data message */
if (conn->curTuple == NULL)
{
conn->curTuple = (PGresAttValue *)
pqResultAlloc(result, nfields * sizeof(PGresAttValue), TRUE);
if (conn->curTuple == NULL)
goto outOfMemory;
MemSet(conn->curTuple, 0, nfields * sizeof(PGresAttValue));
}
tup = conn->curTuple;
/* Get the field count and make sure it's what we expect */
if (pqGetInt(&tupnfields, 2, conn))
return EOF;
if (tupnfields != nfields)
{
/* Replace partially constructed result with an error result */
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("unexpected field count in \"D\" message\n"));
pqSaveErrorResult(conn);
/* Discard the failed message by pretending we read it */
conn->inCursor = conn->inStart + 5 + msgLength;
return 0;
}
/* Scan the fields */
for (i = 0; i < nfields; i++)
{
/* get the value length */
if (pqGetInt(&vlen, 4, conn))
return EOF;
if (vlen == -1)
{
/* null field */
tup[i].value = result->null_field;
tup[i].len = NULL_LEN;
continue;
}
if (vlen < 0)
vlen = 0;
if (tup[i].value == NULL)
{
bool isbinary = (result->attDescs[i].format != 0);
tup[i].value = (char *) pqResultAlloc(result, vlen + 1, isbinary);
if (tup[i].value == NULL)
goto outOfMemory;
}
tup[i].len = vlen;
/* read in the value */
if (vlen > 0)
if (pqGetnchar((char *) (tup[i].value), vlen, conn))
return EOF;
/* we have to terminate this ourselves */
tup[i].value[vlen] = '\0';
}
/* Success! Store the completed tuple in the result */
if (!pqAddTuple(result, tup))
goto outOfMemory;
/* and reset for a new message */
conn->curTuple = NULL;
return 0;
outOfMemory:
/*
* Replace partially constructed result with an error result. First
* discard the old result to try to win back some memory.
*/
pqClearAsyncResult(conn);
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("out of memory for query result\n"));
pqSaveErrorResult(conn);
/* Discard the failed message by pretending we read it */
conn->inCursor = conn->inStart + 5 + msgLength;
return 0;
}
/*
* 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 completed message, EOF if not enough data yet.
*
* 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
getRowDescriptions(PGconn *conn)
{
PGresult *result;
int nfields;
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)
goto failure;
/* parseInput already read the 'T' label and message length. */
/* 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));
}
/* 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))
{
goto failure;
}
/*
* 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)
goto failure;
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;
}
/* Success! */
conn->result = result;
return 0;
failure:
/*
* Discard incomplete result, unless it's from getParamDescriptions.
*
* Note that if we hit a bufferload boundary while handling the
* describe-statement case, we'll forget any PGresult space we just
* allocated, and then reallocate it on next try. This will bloat the
* PGresult a little bit but the space will be freed at PQclear, so it
* doesn't seem worth trying to be smarter.
*/
if (result != conn->result)
PQclear(result);
return EOF;
}
/*
* 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 */
{
pqHandleSendFailure(conn);
return NULL;
}
for (i = 0; i < nargs; ++i)
{ /* len.int4 + contents */
if (pqPutInt(args[i].len, 4, conn))
{
pqHandleSendFailure(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))
{
pqHandleSendFailure(conn);
return NULL;
}
}
else
{
if (pqPutnchar((char *) args[i].u.ptr, args[i].len, conn))
{
pqHandleSendFailure(conn);
return NULL;
}
}
}
if (pqPutInt(1, 2, conn) < 0) /* result format code: BINARY */
{
pqHandleSendFailure(conn);
return NULL;
}
if (pqPutMsgEnd(conn) < 0 ||
pqFlush(conn))
{
pqHandleSendFailure(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 + 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);
}
/*
* parseInput subroutine to read a 'B' or 'D' (row data) message.
* We add another tuple to the existing PGresult structure.
* Returns: 0 if completed message, EOF if error or not enough data yet.
*
* Note that if we run out of data, we have to suspend and reprocess
* the message after more data is received. We keep a partially constructed
* tuple in conn->curTuple, and avoid reallocating already-allocated storage.
*/
static int
getAnotherTuple(PGconn *conn, bool binary)
{
PGresult *result = conn->result;
int nfields = result->numAttributes;
PGresAttValue *tup;
/* the backend sends us a bitmap of which attributes are null */
char std_bitmap[64]; /* used unless it doesn't fit */
char *bitmap = std_bitmap;
int i;
size_t nbytes; /* the number of bytes in bitmap */
char bmap; /* One byte of the bitmap */
int bitmap_index; /* Its index */
int bitcnt; /* number of bits examined in current byte */
int vlen; /* length of the current field value */
result->binary = binary;
/* Allocate tuple space if first time for this data message */
if (conn->curTuple == NULL)
{
conn->curTuple = (PGresAttValue *)
pqResultAlloc(result, nfields * sizeof(PGresAttValue), TRUE);
if (conn->curTuple == NULL)
goto outOfMemory;
MemSet(conn->curTuple, 0, nfields * sizeof(PGresAttValue));
/*
* If it's binary, fix the column format indicators. We assume the
* backend will consistently send either B or D, not a mix.
*/
if (binary)
{
for (i = 0; i < nfields; i++)
result->attDescs[i].format = 1;
}
}
tup = conn->curTuple;
/* Get the null-value bitmap */
nbytes = (nfields + BITS_PER_BYTE - 1) / BITS_PER_BYTE;
/* malloc() only for unusually large field counts... */
if (nbytes > sizeof(std_bitmap))
{
bitmap = (char *) malloc(nbytes);
if (!bitmap)
goto outOfMemory;
}
if (pqGetnchar(bitmap, nbytes, conn))
goto EOFexit;
/* Scan the fields */
bitmap_index = 0;
bmap = bitmap[bitmap_index];
bitcnt = 0;
for (i = 0; i < nfields; i++)
{
if (!(bmap & 0200))
{
/* if the field value is absent, make it a null string */
tup[i].value = result->null_field;
tup[i].len = NULL_LEN;
}
else
{
/* get the value length (the first four bytes are for length) */
if (pqGetInt(&vlen, 4, conn))
goto EOFexit;
if (!binary)
vlen = vlen - 4;
if (vlen < 0)
vlen = 0;
if (tup[i].value == NULL)
{
tup[i].value = (char *) pqResultAlloc(result, vlen + 1, binary);
if (tup[i].value == NULL)
goto outOfMemory;
}
tup[i].len = vlen;
/* read in the value */
if (vlen > 0)
if (pqGetnchar((char *) (tup[i].value), vlen, conn))
goto EOFexit;
/* we have to terminate this ourselves */
tup[i].value[vlen] = '\0';
}
/* advance the bitmap stuff */
bitcnt++;
if (bitcnt == BITS_PER_BYTE)
{
bitmap_index++;
bmap = bitmap[bitmap_index];
bitcnt = 0;
}
else
bmap <<= 1;
}
/* Success! Store the completed tuple in the result */
if (!pqAddTuple(result, tup))
goto outOfMemory;
/* and reset for a new message */
conn->curTuple = NULL;
if (bitmap != std_bitmap)
free(bitmap);
return 0;
outOfMemory:
/* Replace partially constructed result with an error result */
/*
* we do NOT use pqSaveErrorResult() here, because of the likelihood that
* there's not enough memory to concatenate messages...
*/
pqClearAsyncResult(conn);
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("out of memory for query result\n"));
/*
* XXX: if PQmakeEmptyPGresult() fails, there's probably not much we can
* do to recover...
*/
conn->result = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
conn->asyncStatus = PGASYNC_READY;
/* Discard the failed message --- good idea? */
conn->inStart = conn->inEnd;
EOFexit:
if (bitmap != NULL && bitmap != std_bitmap)
free(bitmap);
return EOF;
}
/*
* parseInput subroutine to read a 'T' (row descriptions) message.
* We build a PGresult structure containing the attribute data.
* Returns: 0 if completed message, EOF if not enough data yet.
*
* 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
getRowDescriptions(PGconn *conn)
{
PGresult *result = NULL;
int nfields;
int i;
result = PQmakeEmptyPGresult(conn, PGRES_TUPLES_OK);
if (!result)
goto failure;
/* parseInput already read the 'T' label. */
/* 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));
}
/* get type info */
for (i = 0; i < nfields; i++)
{
int typid;
int typlen;
int atttypmod;
if (pqGets(&conn->workBuffer, conn) ||
pqGetInt(&typid, 4, conn) ||
pqGetInt(&typlen, 2, conn) ||
pqGetInt(&atttypmod, 4, conn))
goto failure;
/*
* Since pqGetInt treats 2-byte integers as unsigned, we need to
* coerce the result to signed form.
*/
typlen = (int) ((int16) typlen);
result->attDescs[i].name = pqResultStrdup(result,
conn->workBuffer.data);
if (!result->attDescs[i].name)
goto failure;
result->attDescs[i].tableid = 0;
result->attDescs[i].columnid = 0;
result->attDescs[i].format = 0;
result->attDescs[i].typid = typid;
result->attDescs[i].typlen = typlen;
result->attDescs[i].atttypmod = atttypmod;
}
/* Success! */
conn->result = result;
return 0;
failure:
if (result)
PQclear(result);
return EOF;
}
/*
* 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;
default: /* treat as end of copy */
return -1;
}
/* Drop the processed message and loop around for another */
conn->inStart = conn->inCursor;
}
}
