/*-------------------------------------------------------------------------
*
* fe-protocol2.c
* functions that are specific to frontend/backend protocol version 2
*
* Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/interfaces/libpq/fe-protocol2.c
*
*-------------------------------------------------------------------------
*/
#include "postgres_fe.h"
#include <ctype.h>
#include <fcntl.h>
#include "libpq-fe.h"
#include "libpq-int.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
static int getRowDescriptions(PGconn *conn);
static int getAnotherTuple(PGconn *conn, bool binary);
static int pqGetErrorNotice2(PGconn *conn, bool isError);
static void checkXactStatus(PGconn *conn, const char *cmdTag);
static int getNotify(PGconn *conn);
/*
* pqSetenvPoll
*
* Polls the process of passing the values of a standard set of environment
* variables to the backend.
*/
PostgresPollingStatusType
pqSetenvPoll(PGconn *conn)
{
PGresult *res;
if (conn == NULL || conn->status == CONNECTION_BAD)
return PGRES_POLLING_FAILED;
/* Check whether there are any data for us */
switch (conn->setenv_state)
{
/* These are reading states */
case SETENV_STATE_CLIENT_ENCODING_WAIT:
case SETENV_STATE_OPTION_WAIT:
case SETENV_STATE_QUERY1_WAIT:
case SETENV_STATE_QUERY2_WAIT:
{
/* Load waiting data */
int n = pqReadData(conn);
if (n < 0)
goto error_return;
if (n == 0)
return PGRES_POLLING_READING;
break;
}
/* These are writing states, so we just proceed. */
case SETENV_STATE_CLIENT_ENCODING_SEND:
case SETENV_STATE_OPTION_SEND:
case SETENV_STATE_QUERY1_SEND:
case SETENV_STATE_QUERY2_SEND:
break;
/* Should we raise an error if called when not active? */
case SETENV_STATE_IDLE:
return PGRES_POLLING_OK;
default:
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext(
"invalid setenv state %c, "
"probably indicative of memory corruption\n"
),
conn->setenv_state);
goto error_return;
}
/* We will loop here until there is nothing left to do in this call. */
for (;;)
{
switch (conn->setenv_state)
{
/*
* The _CLIENT_ENCODING_SEND code is slightly different from
* _OPTION_SEND below (e.g., no getenv() call), which is why a
* different state is used.
*/
case SETENV_STATE_CLIENT_ENCODING_SEND:
{
char setQuery[100]; /* note length limit in
* sprintf below */
const char *val = conn->client_encoding_initial;
if (val)
{
if (pg_strcasecmp(val, "default") == 0)
sprintf(setQuery, "SET client_encoding = DEFAULT");
else
sprintf(setQuery, "SET client_encoding = '%.60s'",
val);
#ifdef CONNECTDEBUG
fprintf(stderr,
"Sending client_encoding with %s\n",
setQuery);
#endif
if (!PQsendQuery(conn, setQuery))
goto error_return;
conn->setenv_state = SETENV_STATE_CLIENT_ENCODING_WAIT;
}
else
conn->setenv_state = SETENV_STATE_OPTION_SEND;
break;
}
case SETENV_STATE_OPTION_SEND:
{
/*
* Send SET commands for stuff directed by Environment
* Options. Note: we assume that SET commands won't start
* transaction blocks, even in a 7.3 server with
* autocommit off.
*/
char setQuery[100]; /* note length limit in
* sprintf below */
if (conn->next_eo->envName)
{
const char *val;
if ((val = getenv(conn->next_eo->envName)))
{
if (pg_strcasecmp(val, "default") == 0)
sprintf(setQuery, "SET %s = DEFAULT",
conn->next_eo->pgName);
else
sprintf(setQuery, "SET %s = '%.60s'",
conn->next_eo->pgName, val);
#ifdef CONNECTDEBUG
fprintf(stderr,
"Use environment variable %s to send %s\n",
conn->next_eo->envName, setQuery);
#endif
if (!PQsendQuery(conn, setQuery))
goto error_return;
conn->setenv_state = SETENV_STATE_OPTION_WAIT;
}
else
conn->next_eo++;
}
else
{
/* No more options to send, so move on to querying */
conn->setenv_state = SETENV_STATE_QUERY1_SEND;
}
break;
}
case SETENV_STATE_CLIENT_ENCODING_WAIT:
{
if (PQisBusy(conn))
return PGRES_POLLING_READING;
res = PQgetResult(conn);
if (res)
{
if (PQresultStatus(res) != PGRES_COMMAND_OK)
{
PQclear(res);
goto error_return;
}
PQclear(res);
/* Keep reading until PQgetResult returns NULL */
}
else
{
/* Query finished, so send the next option */
conn->setenv_state = SETENV_STATE_OPTION_SEND;
}
break;
}
case SETENV_STATE_OPTION_WAIT:
{
if (PQisBusy(conn))
return PGRES_POLLING_READING;
res = PQgetResult(conn);
if (res)
{
if (PQresultStatus(res) != PGRES_COMMAND_OK)
{
PQclear(res);
goto error_return;
}
PQclear(res);
/* Keep reading until PQgetResult returns NULL */
}
else
{
/* Query finished, so send the next option */
conn->next_eo++;
conn->setenv_state = SETENV_STATE_OPTION_SEND;
}
break;
}
case SETENV_STATE_QUERY1_SEND:
{
/*
* Issue query to get information we need. Here we must
* use begin/commit in case autocommit is off by default
* in a 7.3 server.
*
* Note: version() exists in all protocol-2.0-supporting
* backends. In 7.3 it would be safer to write
* pg_catalog.version(), but we can't do that without
* causing problems on older versions.
*/
if (!PQsendQuery(conn, "begin; select version(); end"))
goto error_return;
conn->setenv_state = SETENV_STATE_QUERY1_WAIT;
return PGRES_POLLING_READING;
}
case SETENV_STATE_QUERY1_WAIT:
{
if (PQisBusy(conn))
return PGRES_POLLING_READING;
res = PQgetResult(conn);
if (res)
{
char *val;
if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
/* ignore begin/commit command results */
PQclear(res);
continue;
}
if (PQresultStatus(res) != PGRES_TUPLES_OK ||
PQntuples(res) != 1)
{
PQclear(res);
goto error_return;
}
/*
* Extract server version and save as if
* ParameterStatus
*/
val = PQgetvalue(res, 0, 0);
if (val && strncmp(val, "PostgreSQL ", 11) == 0)
{
char *ptr;
/* strip off PostgreSQL part */
val += 11;
/*
* strip off platform part (scribbles on result,
* naughty naughty)
*/
ptr = strchr(val, ' ');
if (ptr)
*ptr = '\0';
pqSaveParameterStatus(conn, "server_version",
val);
}
PQclear(res);
/* Keep reading until PQgetResult returns NULL */
}
else
{
/* Query finished, move to next */
conn->setenv_state = SETENV_STATE_QUERY2_SEND;
}
break;
}
case SETENV_STATE_QUERY2_SEND:
{
const char *query;
/*
* pg_client_encoding does not exist in pre-7.2 servers.
* So we need to be prepared for an error here. Do *not*
* start a transaction block, except in 7.3 servers where
* we need to prevent autocommit-off from starting a
* transaction anyway.
*/
if (conn->sversion >= 70300 &&
conn->sversion < 70400)
query = "begin; select pg_catalog.pg_client_encoding(); end";
else
query = "select pg_client_encoding()";
if (!PQsendQuery(conn, query))
goto error_return;
conn->setenv_state = SETENV_STATE_QUERY2_WAIT;
return PGRES_POLLING_READING;
}
case SETENV_STATE_QUERY2_WAIT:
{
if (PQisBusy(conn))
return PGRES_POLLING_READING;
res = PQgetResult(conn);
if (res)
{
const char *val;
if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
/* ignore begin/commit command results */
PQclear(res);
continue;
}
if (PQresultStatus(res) == PGRES_TUPLES_OK &&
PQntuples(res) == 1)
{
/* Extract client encoding and save it */
val = PQgetvalue(res, 0, 0);
if (val && *val) /* null should not happen, but */
pqSaveParameterStatus(conn, "client_encoding",
val);
}
else
{
/*
* Error: presumably function not available, so
* use PGCLIENTENCODING or SQL_ASCII as the
* fallback.
*/
val = getenv("PGCLIENTENCODING");
if (val && *val)
pqSaveParameterStatus(conn, "client_encoding",
val);
else
pqSaveParameterStatus(conn, "client_encoding",
"SQL_ASCII");
}
PQclear(res);
/* Keep reading until PQgetResult returns NULL */
}
else
{
/* Query finished, so we're done */
conn->setenv_state = SETENV_STATE_IDLE;
return PGRES_POLLING_OK;
}
break;
}
default:
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("invalid state %c, "
"probably indicative of memory corruption\n"),
conn->setenv_state);
goto error_return;
}
}
/* Unreachable */
error_return:
conn->setenv_state = SETENV_STATE_IDLE;
return PGRES_POLLING_FAILED;
}
/*
* 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;
}
}
/*
* 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 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;
}
/*
* 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 has already been consumed.
* Exit: returns 0 if successfully consumed message.
* returns EOF if not enough data.
*/
static int
pqGetErrorNotice2(PGconn *conn, bool isError)
{
PGresult *res = NULL;
PQExpBufferData workBuf;
char *startp;
char *splitp;
/*
* 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 message 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.
*/
initPQExpBuffer(&workBuf);
if (pqGets(&workBuf, conn))
goto failure;
/*
* Make a PGresult to hold the message. 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;
res->errMsg = pqResultStrdup(res, workBuf.data);
}
/*
* Break the message into fields. We can't do very much here, but we can
* split the severity code off, and remove trailing newlines. Also, we use
* the heuristic that the primary message extends only to the first
* newline --- anything after that is detail message. (In some cases it'd
* be better classed as hint, but we can hardly be expected to guess that
* here.)
*/
while (workBuf.len > 0 && workBuf.data[workBuf.len - 1] == '\n')
workBuf.data[--workBuf.len] = '\0';
splitp = strstr(workBuf.data, ": ");
if (splitp)
{
/* what comes before the colon is severity */
*splitp = '\0';
pqSaveMessageField(res, PG_DIAG_SEVERITY, workBuf.data);
startp = splitp + 3;
}
else
{
/* can't find a colon? oh well... */
startp = workBuf.data;
}
splitp = strchr(startp, '\n');
if (splitp)
{
/* what comes before the newline is primary message */
*splitp++ = '\0';
pqSaveMessageField(res, PG_DIAG_MESSAGE_PRIMARY, startp);
/* the rest is detail; strip any leading whitespace */
while (*splitp && isspace((unsigned char) *splitp))
splitp++;
pqSaveMessageField(res, PG_DIAG_MESSAGE_DETAIL, splitp);
}
else
{
/* single-line message, so all primary */
pqSaveMessageField(res, PG_DIAG_MESSAGE_PRIMARY, startp);
}
/*
* Either save error as current async result, or just emit the notice.
* Also, if it's an error and we were in a transaction block, assume the
* server has now gone to error-in-transaction state.
*/
if (isError)
{
pqClearAsyncResult(conn); /* redundant, but be safe */
conn->result = res;
resetPQExpBuffer(&conn->errorMessage);
if (res && !PQExpBufferDataBroken(workBuf) && res->errMsg)
appendPQExpBufferStr(&conn->errorMessage, res->errMsg);
else
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("out of memory"));
if (conn->xactStatus == PQTRANS_INTRANS)
conn->xactStatus = PQTRANS_INERROR;
}
else
{
if (res)
{
if (res->noticeHooks.noticeRec != NULL)
res->noticeHooks.noticeRec(res->noticeHooks.noticeRecArg, res);
PQclear(res);
}
}
termPQExpBuffer(&workBuf);
return 0;
failure:
if (res)
PQclear(res);
termPQExpBuffer(&workBuf);
return EOF;
}
/*
* checkXactStatus - attempt to track transaction-block status of server
*
* This is called each time we receive a command-complete message. By
* watching for messages from BEGIN/COMMIT/ROLLBACK commands, we can do
* a passable job of tracking the server's xact status. BUT: this does
* not work at all on 7.3 servers with AUTOCOMMIT OFF. (Man, was that
* feature ever a mistake.) Caveat user.
*
* The tags known here are all those used as far back as 7.0; is it worth
* adding those from even-older servers?
*/
static void
checkXactStatus(PGconn *conn, const char *cmdTag)
{
if (strcmp(cmdTag, "BEGIN") == 0)
conn->xactStatus = PQTRANS_INTRANS;
else if (strcmp(cmdTag, "COMMIT") == 0)
conn->xactStatus = PQTRANS_IDLE;
else if (strcmp(cmdTag, "ROLLBACK") == 0)
conn->xactStatus = PQTRANS_IDLE;
else if (strcmp(cmdTag, "START TRANSACTION") == 0) /* 7.3 only */
conn->xactStatus = PQTRANS_INTRANS;
/*
* Normally we get into INERROR state by detecting an Error message.
* However, if we see one of these tags then we know for sure the server
* is in abort state ...
*/
else if (strcmp(cmdTag, "*ABORT STATE*") == 0) /* pre-7.3 only */
conn->xactStatus = PQTRANS_INERROR;
}
/*
* 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;
}
/*
* PQgetCopyData - read a row of data from the backend during COPY OUT
*
* 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
pqGetCopyData2(PGconn *conn, char **buffer, int async)
{
bool found;
int msgLength;
for (;;)
{
/*
* Do we have a complete line of data?
*/
conn->inCursor = conn->inStart;
found = false;
while (conn->inCursor < conn->inEnd)
{
char c = conn->inBuffer[conn->inCursor++];
if (c == '\n')
{
found = true;
break;
}
}
if (!found)
goto nodata;
msgLength = conn->inCursor - conn->inStart;
/*
* If it's the end-of-data marker, consume it, exit COPY_OUT mode, and
* let caller read status with PQgetResult().
*/
if (msgLength == 3 &&
strncmp(&conn->inBuffer[conn->inStart], "\\.\n", 3) == 0)
{
conn->inStart = conn->inCursor;
conn->asyncStatus = PGASYNC_BUSY;
return -1;
}
/*
* Pass the line back to the caller.
*/
*buffer = (char *) malloc(msgLength + 1);
if (*buffer == NULL)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("out of memory\n"));
return -2;
}
memcpy(*buffer, &conn->inBuffer[conn->inStart], msgLength);
(*buffer)[msgLength] = '\0'; /* Add terminating null */
/* Mark message consumed */
conn->inStart = conn->inCursor;
return msgLength;
nodata:
/* 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;
}
}
/*
* PQgetline - gets a newline-terminated string from the backend.
*
* See fe-exec.c for documentation.
*/
int
pqGetline2(PGconn *conn, char *s, int maxlen)
{
int result = 1; /* return value if buffer overflows */
if (conn->sock == PGINVALID_SOCKET ||
conn->asyncStatus != PGASYNC_COPY_OUT)
{
*s = '\0';
return EOF;
}
/*
* Since this is a purely synchronous routine, we don't bother to maintain
* conn->inCursor; there is no need to back up.
*/
while (maxlen > 1)
{
if (conn->inStart < conn->inEnd)
{
char c = conn->inBuffer[conn->inStart++];
if (c == '\n')
{
result = 0; /* success exit */
break;
}
*s++ = c;
maxlen--;
}
else
{
/* need to load more data */
if (pqWait(true, false, conn) ||
pqReadData(conn) < 0)
{
result = EOF;
break;
}
}
}
*s = '\0';
return result;
}
/*
* PQgetlineAsync - gets a COPY data row without blocking.
*
* See fe-exec.c for documentation.
*/
int
pqGetlineAsync2(PGconn *conn, char *buffer, int bufsize)
{
int avail;
if (conn->asyncStatus != PGASYNC_COPY_OUT)
return -1; /* we are not doing a copy... */
/*
* Move data from libpq's buffer to the caller's. We want to accept data
* only in units of whole lines, not partial lines. This ensures that we
* can recognize the terminator line "\\.\n". (Otherwise, if it happened
* to cross a packet/buffer boundary, we might hand the first one or two
* characters off to the caller, which we shouldn't.)
*/
conn->inCursor = conn->inStart;
avail = bufsize;
while (avail > 0 && conn->inCursor < conn->inEnd)
{
char c = conn->inBuffer[conn->inCursor++];
*buffer++ = c;
--avail;
if (c == '\n')
{
/* Got a complete line; mark the data removed from libpq */
conn->inStart = conn->inCursor;
/* Is it the endmarker line? */
if (bufsize - avail == 3 && buffer[-3] == '\\' && buffer[-2] == '.')
return -1;
/* No, return the data line to the caller */
return bufsize - avail;
}
}
/*
* We don't have a complete line. We'd prefer to leave it in libpq's
* buffer until the rest arrives, but there is a special case: what if the
* line is longer than the buffer the caller is offering us? In that case
* we'd better hand over a partial line, else we'd get into an infinite
* loop. Do this in a way that ensures we can't misrecognize a terminator
* line later: leave last 3 characters in libpq buffer.
*/
if (avail == 0 && bufsize > 3)
{
conn->inStart = conn->inCursor - 3;
return bufsize - 3;
}
return 0;
}
/*
* PQendcopy
*
* See fe-exec.c for documentation.
*/
int
pqEndcopy2(PGconn *conn)
{
PGresult *result;
if (conn->asyncStatus != PGASYNC_COPY_IN &&
conn->asyncStatus != PGASYNC_COPY_OUT)
{
printfPQExpBuffer(&conn->errorMessage,
libpq_gettext("no COPY in progress\n"));
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;
/* non blocking connections may have to abort at this point. */
if (pqIsnonblocking(conn) && PQisBusy(conn))
return 1;
/* Return to active duty */
conn->asyncStatus = PGASYNC_BUSY;
resetPQExpBuffer(&conn->errorMessage);
/* 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);
/*
* The worst case is that we've lost sync with the backend entirely due to
* application screwup of the copy in/out protocol. To recover, reset the
* connection (talk about using a sledgehammer...)
*/
pqInternalNotice(&conn->noticeHooks,
"lost synchronization with server, resetting connection");
/*
* Users doing non-blocking connections need to handle the reset
* themselves, they'll need to check the connection status if we return an
* error.
*/
if (pqIsnonblocking(conn))
PQresetStart(conn);
else
PQreset(conn);
return 1;
}
/*
* 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);
}
/*
* Construct startup packet
*
* Returns a malloc'd packet buffer, or NULL if out of memory
*/
char *
pqBuildStartupPacket2(PGconn *conn, int *packetlen,
const PQEnvironmentOption *options)
{
StartupPacket *startpacket;
*packetlen = sizeof(StartupPacket);
startpacket = (StartupPacket *) malloc(sizeof(StartupPacket));
if (!startpacket)
return NULL;
MemSet(startpacket, 0, sizeof(StartupPacket));
startpacket->protoVersion = pg_hton32(conn->pversion);
/* strncpy is safe here: postmaster will handle full fields correctly */
strncpy(startpacket->user, conn->pguser, SM_USER);
strncpy(startpacket->database, conn->dbName, SM_DATABASE);
strncpy(startpacket->tty, conn->pgtty, SM_TTY);
if (conn->pgoptions)
strncpy(startpacket->options, conn->pgoptions, SM_OPTIONS);
return (char *) startpacket;
}