/*
* 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;
}
/*
* 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;
}