diff options
Diffstat (limited to 'src/interfaces/libpq/fe-protocol3.c')
| -rw-r--r-- | src/interfaces/libpq/fe-protocol3.c | 2301 |
1 files changed, 2301 insertions, 0 deletions
diff --git a/src/interfaces/libpq/fe-protocol3.c b/src/interfaces/libpq/fe-protocol3.c new file mode 100644 index 0000000..9c4aa7e --- /dev/null +++ b/src/interfaces/libpq/fe-protocol3.c @@ -0,0 +1,2301 @@ +/*------------------------------------------------------------------------- + * + * fe-protocol3.c + * functions that are specific to frontend/backend protocol version 3 + * + * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * + * IDENTIFICATION + * src/interfaces/libpq/fe-protocol3.c + * + *------------------------------------------------------------------------- + */ +#include "postgres_fe.h" + +#include <ctype.h> +#include <fcntl.h> + +#ifdef WIN32 +#include "win32.h" +#else +#include <unistd.h> +#include <netinet/tcp.h> +#endif + +#include "libpq-fe.h" +#include "libpq-int.h" +#include "mb/pg_wchar.h" +#include "port/pg_bswap.h" + +/* + * This macro lists the backend message types that could be "long" (more + * than a couple of kilobytes). + */ +#define VALID_LONG_MESSAGE_TYPE(id) \ + ((id) == 'T' || (id) == 'D' || (id) == 'd' || (id) == 'V' || \ + (id) == 'E' || (id) == 'N' || (id) == 'A') + + +static void handleSyncLoss(PGconn *conn, char id, int msgLength); +static int getRowDescriptions(PGconn *conn, int msgLength); +static int getParamDescriptions(PGconn *conn, int msgLength); +static int getAnotherTuple(PGconn *conn, int msgLength); +static int getParameterStatus(PGconn *conn); +static int getNotify(PGconn *conn); +static int getCopyStart(PGconn *conn, ExecStatusType copytype); +static int getReadyForQuery(PGconn *conn); +static void reportErrorPosition(PQExpBuffer msg, const char *query, + int loc, int encoding); +static int build_startup_packet(const PGconn *conn, char *packet, + const PQEnvironmentOption *options); + + +/* + * parseInput: if appropriate, parse input data from backend + * until input is exhausted or a stopping state is reached. + * Note that this function will NOT attempt to read more data from the backend. + */ +void +pqParseInput3(PGconn *conn) +{ + char id; + int msgLength; + int avail; + + /* + * Loop to parse successive complete messages available in the buffer. + */ + for (;;) + { + /* + * Try to read a message. First get the type code and length. Return + * if not enough data. + */ + conn->inCursor = conn->inStart; + if (pqGetc(&id, conn)) + return; + if (pqGetInt(&msgLength, 4, conn)) + return; + + /* + * Try to validate message type/length here. A length less than 4 is + * definitely broken. Large lengths should only be believed for a few + * message types. + */ + if (msgLength < 4) + { + handleSyncLoss(conn, id, msgLength); + return; + } + if (msgLength > 30000 && !VALID_LONG_MESSAGE_TYPE(id)) + { + handleSyncLoss(conn, id, msgLength); + return; + } + + /* + * Can't process if message body isn't all here yet. + */ + msgLength -= 4; + avail = conn->inEnd - conn->inCursor; + if (avail < msgLength) + { + /* + * Before returning, enlarge the input buffer if needed to hold + * the whole message. This is better than leaving it to + * pqReadData because we can avoid multiple cycles of realloc() + * when the message is large; also, we can implement a reasonable + * recovery strategy if we are unable to make the buffer big + * enough. + */ + if (pqCheckInBufferSpace(conn->inCursor + (size_t) msgLength, + conn)) + { + /* + * XXX add some better recovery code... plan is to skip over + * the message using its length, then report an error. For the + * moment, just treat this like loss of sync (which indeed it + * might be!) + */ + handleSyncLoss(conn, id, msgLength); + } + return; + } + + /* + * NOTIFY and NOTICE messages can happen in any state; always process + * them right away. + * + * Most other messages should only be processed while in BUSY state. + * (In particular, in READY state we hold off further parsing until + * the application collects the current PGresult.) + * + * However, if the state is IDLE then we got trouble; we need to deal + * with the unexpected message somehow. + * + * ParameterStatus ('S') messages are a special case: in IDLE state we + * must process 'em (this case could happen if a new value was adopted + * from config file due to SIGHUP), but otherwise we hold off until + * BUSY state. + */ + if (id == 'A') + { + if (getNotify(conn)) + return; + } + else if (id == 'N') + { + if (pqGetErrorNotice3(conn, false)) + return; + } + else if (conn->asyncStatus != PGASYNC_BUSY) + { + /* If not IDLE state, just wait ... */ + if (conn->asyncStatus != PGASYNC_IDLE) + return; + + /* + * Unexpected message in IDLE state; need to recover somehow. + * ERROR messages are handled using the notice processor; + * ParameterStatus is handled normally; anything else is just + * dropped on the floor after displaying a suitable warning + * notice. (An ERROR is very possibly the backend telling us why + * it is about to close the connection, so we don't want to just + * discard it...) + */ + if (id == 'E') + { + if (pqGetErrorNotice3(conn, false /* treat as notice */ )) + return; + } + else if (id == 'S') + { + if (getParameterStatus(conn)) + return; + } + else + { + /* Any other case is unexpected and we summarily skip it */ + 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 (!pgHavePendingResult(conn)) + { + conn->result = PQmakeEmptyPGresult(conn, + PGRES_COMMAND_OK); + if (!conn->result) + { + libpq_append_conn_error(conn, "out of memory"); + pqSaveErrorResult(conn); + } + } + if (conn->result) + strlcpy(conn->result->cmdStatus, conn->workBuffer.data, + CMDSTATUS_LEN); + conn->asyncStatus = PGASYNC_READY; + break; + case 'E': /* error return */ + if (pqGetErrorNotice3(conn, true)) + return; + conn->asyncStatus = PGASYNC_READY; + break; + case 'Z': /* sync response, backend is ready for new + * query */ + if (getReadyForQuery(conn)) + return; + if (conn->pipelineStatus != PQ_PIPELINE_OFF) + { + conn->result = PQmakeEmptyPGresult(conn, + PGRES_PIPELINE_SYNC); + if (!conn->result) + { + libpq_append_conn_error(conn, "out of memory"); + pqSaveErrorResult(conn); + } + else + { + conn->pipelineStatus = PQ_PIPELINE_ON; + conn->asyncStatus = PGASYNC_READY; + } + } + else + { + /* Advance the command queue and set us idle */ + pqCommandQueueAdvance(conn, true, false); + conn->asyncStatus = PGASYNC_IDLE; + } + break; + case 'I': /* empty query */ + if (!pgHavePendingResult(conn)) + { + conn->result = PQmakeEmptyPGresult(conn, + PGRES_EMPTY_QUERY); + if (!conn->result) + { + libpq_append_conn_error(conn, "out of memory"); + pqSaveErrorResult(conn); + } + } + conn->asyncStatus = PGASYNC_READY; + break; + case '1': /* Parse Complete */ + /* If we're doing PQprepare, we're done; else ignore */ + if (conn->cmd_queue_head && + conn->cmd_queue_head->queryclass == PGQUERY_PREPARE) + { + if (!pgHavePendingResult(conn)) + { + conn->result = PQmakeEmptyPGresult(conn, + PGRES_COMMAND_OK); + if (!conn->result) + { + libpq_append_conn_error(conn, "out of memory"); + pqSaveErrorResult(conn); + } + } + conn->asyncStatus = PGASYNC_READY; + } + break; + case '2': /* Bind Complete */ + case '3': /* Close Complete */ + /* Nothing to do for these message types */ + break; + case 'S': /* parameter status */ + if (getParameterStatus(conn)) + return; + break; + case 'K': /* secret key data from the backend */ + + /* + * This is expected only during backend startup, but it's + * just as easy to handle it as part of the main loop. + * Save the data and continue processing. + */ + if (pqGetInt(&(conn->be_pid), 4, conn)) + return; + if (pqGetInt(&(conn->be_key), 4, conn)) + return; + break; + case 'T': /* Row Description */ + if (conn->error_result || + (conn->result != NULL && + conn->result->resultStatus == PGRES_FATAL_ERROR)) + { + /* + * We've already choked for some reason. Just discard + * the data till we get to the end of the query. + */ + conn->inCursor += msgLength; + } + else if (conn->result == NULL || + (conn->cmd_queue_head && + conn->cmd_queue_head->queryclass == PGQUERY_DESCRIBE)) + { + /* First 'T' in a query sequence */ + if (getRowDescriptions(conn, msgLength)) + return; + } + else + { + /* + * A new 'T' message is treated as the start of + * another PGresult. (It is not clear that this is + * really possible with the current backend.) We stop + * parsing until the application accepts the current + * result. + */ + conn->asyncStatus = PGASYNC_READY; + return; + } + break; + case 'n': /* No Data */ + + /* + * NoData indicates that we will not be seeing a + * RowDescription message because the statement or portal + * inquired about doesn't return rows. + * + * If we're doing a Describe, we have to pass something + * back to the client, so set up a COMMAND_OK result, + * instead of PGRES_TUPLES_OK. Otherwise we can just + * ignore this message. + */ + if (conn->cmd_queue_head && + conn->cmd_queue_head->queryclass == PGQUERY_DESCRIBE) + { + if (!pgHavePendingResult(conn)) + { + conn->result = PQmakeEmptyPGresult(conn, + PGRES_COMMAND_OK); + if (!conn->result) + { + libpq_append_conn_error(conn, "out of memory"); + pqSaveErrorResult(conn); + } + } + conn->asyncStatus = PGASYNC_READY; + } + break; + case 't': /* Parameter Description */ + if (getParamDescriptions(conn, msgLength)) + 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->error_result || + (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 */ + libpq_append_conn_error(conn, "server sent data (\"D\" message) without prior row description (\"T\" message)"); + pqSaveErrorResult(conn); + /* Discard the unexpected message */ + conn->inCursor += msgLength; + } + break; + case 'G': /* Start Copy In */ + if (getCopyStart(conn, PGRES_COPY_IN)) + return; + conn->asyncStatus = PGASYNC_COPY_IN; + break; + case 'H': /* Start Copy Out */ + if (getCopyStart(conn, PGRES_COPY_OUT)) + return; + conn->asyncStatus = PGASYNC_COPY_OUT; + conn->copy_already_done = 0; + break; + case 'W': /* Start Copy Both */ + if (getCopyStart(conn, PGRES_COPY_BOTH)) + return; + conn->asyncStatus = PGASYNC_COPY_BOTH; + conn->copy_already_done = 0; + break; + case 'd': /* Copy Data */ + + /* + * If we see Copy Data, just silently drop it. This would + * only occur if application exits COPY OUT mode too + * early. + */ + conn->inCursor += msgLength; + break; + case 'c': /* Copy Done */ + + /* + * If we see Copy Done, just silently drop it. This is + * the normal case during PQendcopy. We will keep + * swallowing data, expecting to see command-complete for + * the COPY command. + */ + break; + default: + libpq_append_conn_error(conn, "unexpected response from server; first received character was \"%c\"", 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) + { + /* trace server-to-client message */ + if (conn->Pfdebug) + pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false); + + /* Normal case: parsing agrees with specified length */ + conn->inStart = conn->inCursor; + } + else + { + /* Trouble --- report it */ + libpq_append_conn_error(conn, "message contents do not agree with length in message type \"%c\"", id); + /* build an error result holding the error message */ + pqSaveErrorResult(conn); + conn->asyncStatus = PGASYNC_READY; + /* trust the specified message length as what to skip */ + conn->inStart += 5 + msgLength; + } + } +} + +/* + * handleSyncLoss: clean up after loss of message-boundary sync + * + * There isn't really a lot we can do here except abandon the connection. + */ +static void +handleSyncLoss(PGconn *conn, char id, int msgLength) +{ + libpq_append_conn_error(conn, "lost synchronization with server: got message type \"%c\", length %d", + id, msgLength); + /* build an error result holding the error message */ + pqSaveErrorResult(conn); + conn->asyncStatus = PGASYNC_READY; /* drop out of PQgetResult wait loop */ + /* flush input data since we're giving up on processing it */ + pqDropConnection(conn, true); + conn->status = CONNECTION_BAD; /* No more connection to backend */ +} + +/* + * parseInput subroutine to read a 'T' (row descriptions) message. + * We'll build a new PGresult structure (unless called for a Describe + * command for a prepared statement) containing the attribute data. + * Returns: 0 if processed message successfully, EOF to suspend parsing + * (the latter case is not actually used currently). + */ +static int +getRowDescriptions(PGconn *conn, int msgLength) +{ + PGresult *result; + int nfields; + const char *errmsg; + int i; + + /* + * When doing Describe for a prepared statement, there'll already be a + * PGresult created by getParamDescriptions, and we should fill data into + * that. Otherwise, create a new, empty PGresult. + */ + if (!conn->cmd_queue_head || + (conn->cmd_queue_head && + conn->cmd_queue_head->queryclass == PGQUERY_DESCRIBE)) + { + if (conn->result) + result = conn->result; + else + result = PQmakeEmptyPGresult(conn, PGRES_COMMAND_OK); + } + else + result = PQmakeEmptyPGresult(conn, PGRES_TUPLES_OK); + if (!result) + { + errmsg = NULL; /* means "out of memory", see below */ + goto advance_and_error; + } + + /* parseInput already read the 'T' label and message length. */ + /* the next two bytes are the number of fields */ + if (pqGetInt(&(result->numAttributes), 2, conn)) + { + /* We should not run out of data here, so complain */ + errmsg = libpq_gettext("insufficient data in \"T\" message"); + goto advance_and_error; + } + nfields = result->numAttributes; + + /* allocate space for the attribute descriptors */ + if (nfields > 0) + { + result->attDescs = (PGresAttDesc *) + pqResultAlloc(result, nfields * sizeof(PGresAttDesc), true); + if (!result->attDescs) + { + errmsg = NULL; /* means "out of memory", see below */ + goto advance_and_error; + } + MemSet(result->attDescs, 0, nfields * sizeof(PGresAttDesc)); + } + + /* result->binary is true only if ALL columns are binary */ + result->binary = (nfields > 0) ? 1 : 0; + + /* get type info */ + for (i = 0; i < nfields; i++) + { + int tableid; + int columnid; + int typid; + int typlen; + int atttypmod; + int format; + + if (pqGets(&conn->workBuffer, conn) || + pqGetInt(&tableid, 4, conn) || + pqGetInt(&columnid, 2, conn) || + pqGetInt(&typid, 4, conn) || + pqGetInt(&typlen, 2, conn) || + pqGetInt(&atttypmod, 4, conn) || + pqGetInt(&format, 2, conn)) + { + /* We should not run out of data here, so complain */ + errmsg = libpq_gettext("insufficient data in \"T\" message"); + goto advance_and_error; + } + + /* + * Since pqGetInt treats 2-byte integers as unsigned, we need to + * coerce these results to signed form. + */ + columnid = (int) ((int16) columnid); + typlen = (int) ((int16) typlen); + format = (int) ((int16) format); + + result->attDescs[i].name = pqResultStrdup(result, + conn->workBuffer.data); + if (!result->attDescs[i].name) + { + errmsg = NULL; /* means "out of memory", see below */ + goto advance_and_error; + } + result->attDescs[i].tableid = tableid; + result->attDescs[i].columnid = columnid; + result->attDescs[i].format = format; + result->attDescs[i].typid = typid; + result->attDescs[i].typlen = typlen; + result->attDescs[i].atttypmod = atttypmod; + + if (format != 1) + result->binary = 0; + } + + /* Success! */ + conn->result = result; + + /* + * If we're doing a Describe, we're done, and ready to pass the result + * back to the client. + */ + if ((!conn->cmd_queue_head) || + (conn->cmd_queue_head && + conn->cmd_queue_head->queryclass == PGQUERY_DESCRIBE)) + { + conn->asyncStatus = PGASYNC_READY; + return 0; + } + + /* + * We could perform additional setup for the new result set here, but for + * now there's nothing else to do. + */ + + /* And we're done. */ + return 0; + +advance_and_error: + /* Discard unsaved result, if any */ + if (result && result != conn->result) + PQclear(result); + + /* + * 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"); + + appendPQExpBuffer(&conn->errorMessage, "%s\n", errmsg); + pqSaveErrorResult(conn); + + /* + * Show the message as fully consumed, else pqParseInput3 will overwrite + * our error with a complaint about that. + */ + conn->inCursor = conn->inStart + 5 + msgLength; + + /* + * Return zero to allow input parsing to continue. Subsequent "D" + * messages will be ignored until we get to end of data, since an error + * result is already set up. + */ + return 0; +} + +/* + * parseInput subroutine to read a 't' (ParameterDescription) message. + * We'll build a new PGresult structure containing the parameter data. + * Returns: 0 if processed message successfully, EOF to suspend parsing + * (the latter case is not actually used currently). + */ +static int +getParamDescriptions(PGconn *conn, int msgLength) +{ + PGresult *result; + const char *errmsg = NULL; /* means "out of memory", see below */ + int nparams; + int i; + + result = PQmakeEmptyPGresult(conn, PGRES_COMMAND_OK); + if (!result) + goto advance_and_error; + + /* parseInput already read the 't' label and message length. */ + /* the next two bytes are the number of parameters */ + if (pqGetInt(&(result->numParameters), 2, conn)) + goto not_enough_data; + nparams = result->numParameters; + + /* allocate space for the parameter descriptors */ + if (nparams > 0) + { + result->paramDescs = (PGresParamDesc *) + pqResultAlloc(result, nparams * sizeof(PGresParamDesc), true); + if (!result->paramDescs) + goto advance_and_error; + MemSet(result->paramDescs, 0, nparams * sizeof(PGresParamDesc)); + } + + /* get parameter info */ + for (i = 0; i < nparams; i++) + { + int typid; + + if (pqGetInt(&typid, 4, conn)) + goto not_enough_data; + result->paramDescs[i].typid = typid; + } + + /* Success! */ + conn->result = result; + + return 0; + +not_enough_data: + errmsg = libpq_gettext("insufficient data in \"t\" message"); + +advance_and_error: + /* Discard unsaved result, if any */ + if (result && result != conn->result) + PQclear(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"); + appendPQExpBuffer(&conn->errorMessage, "%s\n", errmsg); + pqSaveErrorResult(conn); + + /* + * Show the message as fully consumed, else pqParseInput3 will overwrite + * our error with a complaint about that. + */ + conn->inCursor = conn->inStart + 5 + msgLength; + + /* + * Return zero to allow input parsing to continue. Essentially, we've + * replaced the COMMAND_OK result with an error result, but since this + * doesn't affect the protocol state, it's fine. + */ + return 0; +} + +/* + * parseInput subroutine to read a 'D' (row data) message. + * We fill rowbuf with column pointers and then call the row processor. + * Returns: 0 if processed message successfully, EOF to suspend parsing + * (the latter case is not actually used currently). + */ +static int +getAnotherTuple(PGconn *conn, int msgLength) +{ + PGresult *result = conn->result; + int nfields = result->numAttributes; + const char *errmsg; + PGdataValue *rowbuf; + int tupnfields; /* # fields from tuple */ + int vlen; /* length of the current field value */ + int i; + + /* Get the field count and make sure it's what we expect */ + if (pqGetInt(&tupnfields, 2, conn)) + { + /* We should not run out of data here, so complain */ + errmsg = libpq_gettext("insufficient data in \"D\" message"); + goto advance_and_error; + } + + if (tupnfields != nfields) + { + errmsg = libpq_gettext("unexpected field count in \"D\" message"); + goto advance_and_error; + } + + /* Resize row buffer if needed */ + rowbuf = conn->rowBuf; + if (nfields > conn->rowBufLen) + { + rowbuf = (PGdataValue *) realloc(rowbuf, + nfields * sizeof(PGdataValue)); + if (!rowbuf) + { + errmsg = NULL; /* means "out of memory", see below */ + goto advance_and_error; + } + conn->rowBuf = rowbuf; + conn->rowBufLen = nfields; + } + + /* Scan the fields */ + for (i = 0; i < nfields; i++) + { + /* get the value length */ + if (pqGetInt(&vlen, 4, conn)) + { + /* We should not run out of data here, so complain */ + errmsg = libpq_gettext("insufficient data in \"D\" message"); + goto advance_and_error; + } + rowbuf[i].len = vlen; + + /* + * rowbuf[i].value always points to the next address in the data + * buffer even if the value is NULL. This allows row processors to + * estimate data sizes more easily. + */ + rowbuf[i].value = conn->inBuffer + conn->inCursor; + + /* Skip over the data value */ + if (vlen > 0) + { + if (pqSkipnchar(vlen, conn)) + { + /* We should not run out of data here, so complain */ + errmsg = libpq_gettext("insufficient data in \"D\" message"); + goto advance_and_error; + } + } + } + + /* Process the collected row */ + errmsg = NULL; + if (pqRowProcessor(conn, &errmsg)) + return 0; /* normal, successful exit */ + + /* pqRowProcessor failed, fall through to report it */ + +advance_and_error: + + /* + * 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"); + + appendPQExpBuffer(&conn->errorMessage, "%s\n", errmsg); + pqSaveErrorResult(conn); + + /* + * Show the message as fully consumed, else pqParseInput3 will overwrite + * our error with a complaint about that. + */ + conn->inCursor = conn->inStart + 5 + msgLength; + + /* + * Return zero to allow input parsing to continue. Subsequent "D" + * messages will be ignored until we get to end of data, since an error + * result is already set up. + */ + return 0; +} + + +/* + * Attempt to read an Error or Notice response message. + * This is possible in several places, so we break it out as a subroutine. + * Entry: 'E' or 'N' message type and length have already been consumed. + * Exit: returns 0 if successfully consumed message. + * returns EOF if not enough data. + */ +int +pqGetErrorNotice3(PGconn *conn, bool isError) +{ + PGresult *res = NULL; + bool have_position = false; + PQExpBufferData workBuf; + char id; + + /* If in pipeline mode, set error indicator for it */ + if (isError && conn->pipelineStatus != PQ_PIPELINE_OFF) + conn->pipelineStatus = PQ_PIPELINE_ABORTED; + + /* + * If this is an error message, pre-emptively clear any incomplete query + * result we may have. We'd just throw it away below anyway, and + * releasing it before collecting the error might avoid out-of-memory. + */ + if (isError) + pqClearAsyncResult(conn); + + /* + * Since the fields might be pretty long, we create a temporary + * PQExpBuffer rather than using conn->workBuffer. workBuffer is intended + * for stuff that is expected to be short. We shouldn't use + * conn->errorMessage either, since this might be only a notice. + */ + initPQExpBuffer(&workBuf); + + /* + * Make a PGresult to hold the accumulated fields. We temporarily lie + * about the result status, so that PQmakeEmptyPGresult doesn't uselessly + * copy conn->errorMessage. + * + * NB: This allocation can fail, if you run out of memory. The rest of the + * function handles that gracefully, and we still try to set the error + * message as the connection's error message. + */ + res = PQmakeEmptyPGresult(conn, PGRES_EMPTY_QUERY); + if (res) + res->resultStatus = isError ? PGRES_FATAL_ERROR : PGRES_NONFATAL_ERROR; + + /* + * Read the fields and save into res. + * + * While at it, save the SQLSTATE in conn->last_sqlstate, and note whether + * we saw a PG_DIAG_STATEMENT_POSITION field. + */ + for (;;) + { + if (pqGetc(&id, conn)) + goto fail; + if (id == '\0') + break; /* terminator found */ + if (pqGets(&workBuf, conn)) + goto fail; + pqSaveMessageField(res, id, workBuf.data); + if (id == PG_DIAG_SQLSTATE) + strlcpy(conn->last_sqlstate, workBuf.data, + sizeof(conn->last_sqlstate)); + else if (id == PG_DIAG_STATEMENT_POSITION) + have_position = true; + } + + /* + * Save the active query text, if any, into res as well; but only if we + * might need it for an error cursor display, which is only true if there + * is a PG_DIAG_STATEMENT_POSITION field. + */ + if (have_position && res && conn->cmd_queue_head && conn->cmd_queue_head->query) + res->errQuery = pqResultStrdup(res, conn->cmd_queue_head->query); + + /* + * Now build the "overall" error message for PQresultErrorMessage. + */ + resetPQExpBuffer(&workBuf); + pqBuildErrorMessage3(&workBuf, res, conn->verbosity, conn->show_context); + + /* + * Either save error as current async result, or just emit the notice. + */ + if (isError) + { + pqClearAsyncResult(conn); /* redundant, but be safe */ + if (res) + { + pqSetResultError(res, &workBuf, 0); + conn->result = res; + } + else + { + /* Fall back to using the internal-error processing paths */ + conn->error_result = true; + } + + if (PQExpBufferDataBroken(workBuf)) + libpq_append_conn_error(conn, "out of memory"); + else + appendPQExpBufferStr(&conn->errorMessage, workBuf.data); + } + else + { + /* if we couldn't allocate the result set, just discard the NOTICE */ + if (res) + { + /* + * We can cheat a little here and not copy the message. But if we + * were unlucky enough to run out of memory while filling workBuf, + * insert "out of memory", as in pqSetResultError. + */ + if (PQExpBufferDataBroken(workBuf)) + res->errMsg = libpq_gettext("out of memory\n"); + else + res->errMsg = workBuf.data; + if (res->noticeHooks.noticeRec != NULL) + res->noticeHooks.noticeRec(res->noticeHooks.noticeRecArg, res); + PQclear(res); + } + } + + termPQExpBuffer(&workBuf); + return 0; + +fail: + PQclear(res); + termPQExpBuffer(&workBuf); + return EOF; +} + +/* + * Construct an error message from the fields in the given PGresult, + * appending it to the contents of "msg". + */ +void +pqBuildErrorMessage3(PQExpBuffer msg, const PGresult *res, + PGVerbosity verbosity, PGContextVisibility show_context) +{ + const char *val; + const char *querytext = NULL; + int querypos = 0; + + /* If we couldn't allocate a PGresult, just say "out of memory" */ + if (res == NULL) + { + appendPQExpBufferStr(msg, libpq_gettext("out of memory\n")); + return; + } + + /* + * If we don't have any broken-down fields, just return the base message. + * This mainly applies if we're given a libpq-generated error result. + */ + if (res->errFields == NULL) + { + if (res->errMsg && res->errMsg[0]) + appendPQExpBufferStr(msg, res->errMsg); + else + appendPQExpBufferStr(msg, libpq_gettext("no error message available\n")); + return; + } + + /* Else build error message from relevant fields */ + val = PQresultErrorField(res, PG_DIAG_SEVERITY); + if (val) + appendPQExpBuffer(msg, "%s: ", val); + + if (verbosity == PQERRORS_SQLSTATE) + { + /* + * If we have a SQLSTATE, print that and nothing else. If not (which + * shouldn't happen for server-generated errors, but might possibly + * happen for libpq-generated ones), fall back to TERSE format, as + * that seems better than printing nothing at all. + */ + val = PQresultErrorField(res, PG_DIAG_SQLSTATE); + if (val) + { + appendPQExpBuffer(msg, "%s\n", val); + return; + } + verbosity = PQERRORS_TERSE; + } + + if (verbosity == PQERRORS_VERBOSE) + { + val = PQresultErrorField(res, PG_DIAG_SQLSTATE); + if (val) + appendPQExpBuffer(msg, "%s: ", val); + } + val = PQresultErrorField(res, PG_DIAG_MESSAGE_PRIMARY); + if (val) + appendPQExpBufferStr(msg, val); + val = PQresultErrorField(res, PG_DIAG_STATEMENT_POSITION); + if (val) + { + if (verbosity != PQERRORS_TERSE && res->errQuery != NULL) + { + /* emit position as a syntax cursor display */ + querytext = res->errQuery; + querypos = atoi(val); + } + else + { + /* emit position as text addition to primary message */ + /* translator: %s represents a digit string */ + appendPQExpBuffer(msg, libpq_gettext(" at character %s"), + val); + } + } + else + { + val = PQresultErrorField(res, PG_DIAG_INTERNAL_POSITION); + if (val) + { + querytext = PQresultErrorField(res, PG_DIAG_INTERNAL_QUERY); + if (verbosity != PQERRORS_TERSE && querytext != NULL) + { + /* emit position as a syntax cursor display */ + querypos = atoi(val); + } + else + { + /* emit position as text addition to primary message */ + /* translator: %s represents a digit string */ + appendPQExpBuffer(msg, libpq_gettext(" at character %s"), + val); + } + } + } + appendPQExpBufferChar(msg, '\n'); + if (verbosity != PQERRORS_TERSE) + { + if (querytext && querypos > 0) + reportErrorPosition(msg, querytext, querypos, + res->client_encoding); + val = PQresultErrorField(res, PG_DIAG_MESSAGE_DETAIL); + if (val) + appendPQExpBuffer(msg, libpq_gettext("DETAIL: %s\n"), val); + val = PQresultErrorField(res, PG_DIAG_MESSAGE_HINT); + if (val) + appendPQExpBuffer(msg, libpq_gettext("HINT: %s\n"), val); + val = PQresultErrorField(res, PG_DIAG_INTERNAL_QUERY); + if (val) + appendPQExpBuffer(msg, libpq_gettext("QUERY: %s\n"), val); + if (show_context == PQSHOW_CONTEXT_ALWAYS || + (show_context == PQSHOW_CONTEXT_ERRORS && + res->resultStatus == PGRES_FATAL_ERROR)) + { + val = PQresultErrorField(res, PG_DIAG_CONTEXT); + if (val) + appendPQExpBuffer(msg, libpq_gettext("CONTEXT: %s\n"), + val); + } + } + if (verbosity == PQERRORS_VERBOSE) + { + val = PQresultErrorField(res, PG_DIAG_SCHEMA_NAME); + if (val) + appendPQExpBuffer(msg, + libpq_gettext("SCHEMA NAME: %s\n"), val); + val = PQresultErrorField(res, PG_DIAG_TABLE_NAME); + if (val) + appendPQExpBuffer(msg, + libpq_gettext("TABLE NAME: %s\n"), val); + val = PQresultErrorField(res, PG_DIAG_COLUMN_NAME); + if (val) + appendPQExpBuffer(msg, + libpq_gettext("COLUMN NAME: %s\n"), val); + val = PQresultErrorField(res, PG_DIAG_DATATYPE_NAME); + if (val) + appendPQExpBuffer(msg, + libpq_gettext("DATATYPE NAME: %s\n"), val); + val = PQresultErrorField(res, PG_DIAG_CONSTRAINT_NAME); + if (val) + appendPQExpBuffer(msg, + libpq_gettext("CONSTRAINT NAME: %s\n"), val); + } + if (verbosity == PQERRORS_VERBOSE) + { + const char *valf; + const char *vall; + + valf = PQresultErrorField(res, PG_DIAG_SOURCE_FILE); + vall = PQresultErrorField(res, PG_DIAG_SOURCE_LINE); + val = PQresultErrorField(res, PG_DIAG_SOURCE_FUNCTION); + if (val || valf || vall) + { + appendPQExpBufferStr(msg, libpq_gettext("LOCATION: ")); + if (val) + appendPQExpBuffer(msg, libpq_gettext("%s, "), val); + if (valf && vall) /* unlikely we'd have just one */ + appendPQExpBuffer(msg, libpq_gettext("%s:%s"), + valf, vall); + appendPQExpBufferChar(msg, '\n'); + } + } +} + +/* + * Add an error-location display to the error message under construction. + * + * The cursor location is measured in logical characters; the query string + * is presumed to be in the specified encoding. + */ +static void +reportErrorPosition(PQExpBuffer msg, const char *query, int loc, int encoding) +{ +#define DISPLAY_SIZE 60 /* screen width limit, in screen cols */ +#define MIN_RIGHT_CUT 10 /* try to keep this far away from EOL */ + + char *wquery; + int slen, + cno, + i, + *qidx, + *scridx, + qoffset, + scroffset, + ibeg, + iend, + loc_line; + bool mb_encoding, + beg_trunc, + end_trunc; + + /* Convert loc from 1-based to 0-based; no-op if out of range */ + loc--; + if (loc < 0) + return; + + /* Need a writable copy of the query */ + wquery = strdup(query); + if (wquery == NULL) + return; /* fail silently if out of memory */ + + /* + * Each character might occupy multiple physical bytes in the string, and + * in some Far Eastern character sets it might take more than one screen + * column as well. We compute the starting byte offset and starting + * screen column of each logical character, and store these in qidx[] and + * scridx[] respectively. + */ + + /* we need a safe allocation size... */ + slen = strlen(wquery) + 1; + + qidx = (int *) malloc(slen * sizeof(int)); + if (qidx == NULL) + { + free(wquery); + return; + } + scridx = (int *) malloc(slen * sizeof(int)); + if (scridx == NULL) + { + free(qidx); + free(wquery); + return; + } + + /* We can optimize a bit if it's a single-byte encoding */ + mb_encoding = (pg_encoding_max_length(encoding) != 1); + + /* + * Within the scanning loop, cno is the current character's logical + * number, qoffset is its offset in wquery, and scroffset is its starting + * logical screen column (all indexed from 0). "loc" is the logical + * character number of the error location. We scan to determine loc_line + * (the 1-based line number containing loc) and ibeg/iend (first character + * number and last+1 character number of the line containing loc). Note + * that qidx[] and scridx[] are filled only as far as iend. + */ + qoffset = 0; + scroffset = 0; + loc_line = 1; + ibeg = 0; + iend = -1; /* -1 means not set yet */ + + for (cno = 0; wquery[qoffset] != '\0'; cno++) + { + char ch = wquery[qoffset]; + + qidx[cno] = qoffset; + scridx[cno] = scroffset; + + /* + * Replace tabs with spaces in the writable copy. (Later we might + * want to think about coping with their variable screen width, but + * not today.) + */ + if (ch == '\t') + wquery[qoffset] = ' '; + + /* + * If end-of-line, count lines and mark positions. Each \r or \n + * counts as a line except when \r \n appear together. + */ + else if (ch == '\r' || ch == '\n') + { + if (cno < loc) + { + if (ch == '\r' || + cno == 0 || + wquery[qidx[cno - 1]] != '\r') + loc_line++; + /* extract beginning = last line start before loc. */ + ibeg = cno + 1; + } + else + { + /* set extract end. */ + iend = cno; + /* done scanning. */ + break; + } + } + + /* Advance */ + if (mb_encoding) + { + int w; + + w = pg_encoding_dsplen(encoding, &wquery[qoffset]); + /* treat any non-tab control chars as width 1 */ + if (w <= 0) + w = 1; + scroffset += w; + qoffset += PQmblenBounded(&wquery[qoffset], encoding); + } + else + { + /* We assume wide chars only exist in multibyte encodings */ + scroffset++; + qoffset++; + } + } + /* Fix up if we didn't find an end-of-line after loc */ + if (iend < 0) + { + iend = cno; /* query length in chars, +1 */ + qidx[iend] = qoffset; + scridx[iend] = scroffset; + } + + /* Print only if loc is within computed query length */ + if (loc <= cno) + { + /* If the line extracted is too long, we truncate it. */ + beg_trunc = false; + end_trunc = false; + if (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE) + { + /* + * We first truncate right if it is enough. This code might be + * off a space or so on enforcing MIN_RIGHT_CUT if there's a wide + * character right there, but that should be okay. + */ + if (scridx[ibeg] + DISPLAY_SIZE >= scridx[loc] + MIN_RIGHT_CUT) + { + while (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE) + iend--; + end_trunc = true; + } + else + { + /* Truncate right if not too close to loc. */ + while (scridx[loc] + MIN_RIGHT_CUT < scridx[iend]) + { + iend--; + end_trunc = true; + } + + /* Truncate left if still too long. */ + while (scridx[iend] - scridx[ibeg] > DISPLAY_SIZE) + { + ibeg++; + beg_trunc = true; + } + } + } + + /* truncate working copy at desired endpoint */ + wquery[qidx[iend]] = '\0'; + + /* Begin building the finished message. */ + i = msg->len; + appendPQExpBuffer(msg, libpq_gettext("LINE %d: "), loc_line); + if (beg_trunc) + appendPQExpBufferStr(msg, "..."); + + /* + * While we have the prefix in the msg buffer, compute its screen + * width. + */ + scroffset = 0; + for (; i < msg->len; i += PQmblenBounded(&msg->data[i], encoding)) + { + int w = pg_encoding_dsplen(encoding, &msg->data[i]); + + if (w <= 0) + w = 1; + scroffset += w; + } + + /* Finish up the LINE message line. */ + appendPQExpBufferStr(msg, &wquery[qidx[ibeg]]); + if (end_trunc) + appendPQExpBufferStr(msg, "..."); + appendPQExpBufferChar(msg, '\n'); + + /* Now emit the cursor marker line. */ + scroffset += scridx[loc] - scridx[ibeg]; + for (i = 0; i < scroffset; i++) + appendPQExpBufferChar(msg, ' '); + appendPQExpBufferChar(msg, '^'); + appendPQExpBufferChar(msg, '\n'); + } + + /* Clean up. */ + free(scridx); + free(qidx); + free(wquery); +} + + +/* + * Attempt to read a NegotiateProtocolVersion message. + * Entry: 'v' message type and length have already been consumed. + * Exit: returns 0 if successfully consumed message. + * returns EOF if not enough data. + */ +int +pqGetNegotiateProtocolVersion3(PGconn *conn) +{ + int tmp; + ProtocolVersion their_version; + int num; + PQExpBufferData buf; + + if (pqGetInt(&tmp, 4, conn) != 0) + return EOF; + their_version = tmp; + + if (pqGetInt(&num, 4, conn) != 0) + return EOF; + + initPQExpBuffer(&buf); + for (int i = 0; i < num; i++) + { + if (pqGets(&conn->workBuffer, conn)) + { + termPQExpBuffer(&buf); + return EOF; + } + if (buf.len > 0) + appendPQExpBufferChar(&buf, ' '); + appendPQExpBufferStr(&buf, conn->workBuffer.data); + } + + if (their_version < conn->pversion) + libpq_append_conn_error(conn, "protocol version not supported by server: client uses %u.%u, server supports up to %u.%u", + PG_PROTOCOL_MAJOR(conn->pversion), PG_PROTOCOL_MINOR(conn->pversion), + PG_PROTOCOL_MAJOR(their_version), PG_PROTOCOL_MINOR(their_version)); + if (num > 0) + { + appendPQExpBuffer(&conn->errorMessage, + libpq_ngettext("protocol extension not supported by server: %s", + "protocol extensions not supported by server: %s", num), + buf.data); + appendPQExpBufferChar(&conn->errorMessage, '\n'); + } + + /* neither -- server shouldn't have sent it */ + if (!(their_version < conn->pversion) && !(num > 0)) + libpq_append_conn_error(conn, "invalid %s message", "NegotiateProtocolVersion"); + + termPQExpBuffer(&buf); + return 0; +} + + +/* + * Attempt to read a ParameterStatus message. + * This is possible in several places, so we break it out as a subroutine. + * Entry: 'S' message type and length have already been consumed. + * Exit: returns 0 if successfully consumed message. + * returns EOF if not enough data. + */ +static int +getParameterStatus(PGconn *conn) +{ + PQExpBufferData valueBuf; + + /* Get the parameter name */ + if (pqGets(&conn->workBuffer, conn)) + return EOF; + /* Get the parameter value (could be large) */ + initPQExpBuffer(&valueBuf); + if (pqGets(&valueBuf, conn)) + { + termPQExpBuffer(&valueBuf); + return EOF; + } + /* And save it */ + pqSaveParameterStatus(conn, conn->workBuffer.data, valueBuf.data); + termPQExpBuffer(&valueBuf); + return 0; +} + + +/* + * Attempt to read a Notify response message. + * This is possible in several places, so we break it out as a subroutine. + * Entry: 'A' message type and length have already been consumed. + * Exit: returns 0 if successfully consumed Notify message. + * returns EOF if not enough data. + */ +static int +getNotify(PGconn *conn) +{ + int be_pid; + char *svname; + int nmlen; + int extralen; + PGnotify *newNotify; + + if (pqGetInt(&be_pid, 4, conn)) + return EOF; + if (pqGets(&conn->workBuffer, conn)) + return EOF; + /* must save name while getting extra string */ + svname = strdup(conn->workBuffer.data); + if (!svname) + return EOF; + if (pqGets(&conn->workBuffer, conn)) + { + free(svname); + return EOF; + } + + /* + * Store the strings right after the PGnotify structure so it can all be + * freed at once. We don't use NAMEDATALEN because we don't want to tie + * this interface to a specific server name length. + */ + nmlen = strlen(svname); + extralen = strlen(conn->workBuffer.data); + newNotify = (PGnotify *) malloc(sizeof(PGnotify) + nmlen + extralen + 2); + if (newNotify) + { + newNotify->relname = (char *) newNotify + sizeof(PGnotify); + strcpy(newNotify->relname, svname); + newNotify->extra = newNotify->relname + nmlen + 1; + strcpy(newNotify->extra, conn->workBuffer.data); + newNotify->be_pid = be_pid; + newNotify->next = NULL; + if (conn->notifyTail) + conn->notifyTail->next = newNotify; + else + conn->notifyHead = newNotify; + conn->notifyTail = newNotify; + } + + free(svname); + return 0; +} + +/* + * getCopyStart - process CopyInResponse, CopyOutResponse or + * CopyBothResponse message + * + * parseInput already read the message type and length. + */ +static int +getCopyStart(PGconn *conn, ExecStatusType copytype) +{ + PGresult *result; + int nfields; + int i; + + result = PQmakeEmptyPGresult(conn, copytype); + if (!result) + goto failure; + + if (pqGetc(&conn->copy_is_binary, conn)) + goto failure; + result->binary = conn->copy_is_binary; + /* the next two bytes are the number of fields */ + if (pqGetInt(&(result->numAttributes), 2, conn)) + goto failure; + nfields = result->numAttributes; + + /* allocate space for the attribute descriptors */ + if (nfields > 0) + { + result->attDescs = (PGresAttDesc *) + pqResultAlloc(result, nfields * sizeof(PGresAttDesc), true); + if (!result->attDescs) + goto failure; + MemSet(result->attDescs, 0, nfields * sizeof(PGresAttDesc)); + } + + for (i = 0; i < nfields; i++) + { + int format; + + if (pqGetInt(&format, 2, conn)) + goto failure; + + /* + * Since pqGetInt treats 2-byte integers as unsigned, we need to + * coerce these results to signed form. + */ + format = (int) ((int16) format); + result->attDescs[i].format = format; + } + + /* Success! */ + conn->result = result; + return 0; + +failure: + PQclear(result); + return EOF; +} + +/* + * getReadyForQuery - process ReadyForQuery message + */ +static int +getReadyForQuery(PGconn *conn) +{ + char xact_status; + + if (pqGetc(&xact_status, conn)) + return EOF; + switch (xact_status) + { + case 'I': + conn->xactStatus = PQTRANS_IDLE; + break; + case 'T': + conn->xactStatus = PQTRANS_INTRANS; + break; + case 'E': + conn->xactStatus = PQTRANS_INERROR; + break; + default: + conn->xactStatus = PQTRANS_UNKNOWN; + break; + } + + return 0; +} + +/* + * getCopyDataMessage - fetch next CopyData message, process async messages + * + * Returns length word of CopyData message (> 0), or 0 if no complete + * message available, -1 if end of copy, -2 if error. + */ +static int +getCopyDataMessage(PGconn *conn) +{ + char id; + int msgLength; + int avail; + + for (;;) + { + /* + * Do we have the next input message? To make life simpler for async + * callers, we keep returning 0 until the next message is fully + * available, even if it is not Copy Data. + */ + conn->inCursor = conn->inStart; + if (pqGetc(&id, conn)) + return 0; + if (pqGetInt(&msgLength, 4, conn)) + return 0; + if (msgLength < 4) + { + handleSyncLoss(conn, id, msgLength); + return -2; + } + avail = conn->inEnd - conn->inCursor; + if (avail < msgLength - 4) + { + /* + * Before returning, enlarge the input buffer if needed to hold + * the whole message. See notes in parseInput. + */ + if (pqCheckInBufferSpace(conn->inCursor + (size_t) msgLength - 4, + conn)) + { + /* + * XXX add some better recovery code... plan is to skip over + * the message using its length, then report an error. For the + * moment, just treat this like loss of sync (which indeed it + * might be!) + */ + handleSyncLoss(conn, id, msgLength); + return -2; + } + return 0; + } + + /* + * If it's a legitimate async message type, process it. (NOTIFY + * messages are not currently possible here, but we handle them for + * completeness.) Otherwise, if it's anything except Copy Data, + * report end-of-copy. + */ + switch (id) + { + case 'A': /* NOTIFY */ + if (getNotify(conn)) + return 0; + break; + case 'N': /* NOTICE */ + if (pqGetErrorNotice3(conn, false)) + return 0; + break; + case 'S': /* ParameterStatus */ + if (getParameterStatus(conn)) + return 0; + break; + case 'd': /* Copy Data, pass it back to caller */ + return msgLength; + case 'c': + + /* + * If this is a CopyDone message, exit COPY_OUT mode and let + * caller read status with PQgetResult(). If we're in + * COPY_BOTH mode, return to COPY_IN mode. + */ + if (conn->asyncStatus == PGASYNC_COPY_BOTH) + conn->asyncStatus = PGASYNC_COPY_IN; + else + conn->asyncStatus = PGASYNC_BUSY; + return -1; + default: /* treat as end of copy */ + + /* + * Any other message terminates either COPY_IN or COPY_BOTH + * mode. + */ + conn->asyncStatus = PGASYNC_BUSY; + return -1; + } + + /* trace server-to-client message */ + if (conn->Pfdebug) + pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false); + + /* Drop the processed message and loop around for another */ + conn->inStart = conn->inCursor; + } +} + +/* + * PQgetCopyData - read a row of data from the backend during COPY OUT + * or COPY BOTH + * + * If successful, sets *buffer to point to a malloc'd row of data, and + * returns row length (always > 0) as result. + * Returns 0 if no row available yet (only possible if async is true), + * -1 if end of copy (consult PQgetResult), or -2 if error (consult + * PQerrorMessage). + */ +int +pqGetCopyData3(PGconn *conn, char **buffer, int async) +{ + int msgLength; + + for (;;) + { + /* + * Collect the next input message. To make life simpler for async + * callers, we keep returning 0 until the next message is fully + * available, even if it is not Copy Data. + */ + msgLength = getCopyDataMessage(conn); + if (msgLength < 0) + return msgLength; /* end-of-copy or error */ + if (msgLength == 0) + { + /* Don't block if async read requested */ + if (async) + return 0; + /* Need to load more data */ + if (pqWait(true, false, conn) || + pqReadData(conn) < 0) + return -2; + continue; + } + + /* + * Drop zero-length messages (shouldn't happen anyway). Otherwise + * pass the data back to the caller. + */ + msgLength -= 4; + if (msgLength > 0) + { + *buffer = (char *) malloc(msgLength + 1); + if (*buffer == NULL) + { + libpq_append_conn_error(conn, "out of memory"); + return -2; + } + memcpy(*buffer, &conn->inBuffer[conn->inCursor], msgLength); + (*buffer)[msgLength] = '\0'; /* Add terminating null */ + + /* Mark message consumed */ + conn->inStart = conn->inCursor + msgLength; + + return msgLength; + } + + /* Empty, so drop it and loop around for another */ + conn->inStart = conn->inCursor; + } +} + +/* + * PQgetline - gets a newline-terminated string from the backend. + * + * See fe-exec.c for documentation. + */ +int +pqGetline3(PGconn *conn, char *s, int maxlen) +{ + int status; + + if (conn->sock == PGINVALID_SOCKET || + (conn->asyncStatus != PGASYNC_COPY_OUT && + conn->asyncStatus != PGASYNC_COPY_BOTH) || + conn->copy_is_binary) + { + libpq_append_conn_error(conn, "PQgetline: not doing text COPY OUT"); + *s = '\0'; + return EOF; + } + + while ((status = PQgetlineAsync(conn, s, maxlen - 1)) == 0) + { + /* need to load more data */ + if (pqWait(true, false, conn) || + pqReadData(conn) < 0) + { + *s = '\0'; + return EOF; + } + } + + if (status < 0) + { + /* End of copy detected; gin up old-style terminator */ + strcpy(s, "\\."); + return 0; + } + + /* Add null terminator, and strip trailing \n if present */ + if (s[status - 1] == '\n') + { + s[status - 1] = '\0'; + return 0; + } + else + { + s[status] = '\0'; + return 1; + } +} + +/* + * PQgetlineAsync - gets a COPY data row without blocking. + * + * See fe-exec.c for documentation. + */ +int +pqGetlineAsync3(PGconn *conn, char *buffer, int bufsize) +{ + int msgLength; + int avail; + + if (conn->asyncStatus != PGASYNC_COPY_OUT + && conn->asyncStatus != PGASYNC_COPY_BOTH) + return -1; /* we are not doing a copy... */ + + /* + * Recognize the next input message. To make life simpler for async + * callers, we keep returning 0 until the next message is fully available + * even if it is not Copy Data. This should keep PQendcopy from blocking. + * (Note: unlike pqGetCopyData3, we do not change asyncStatus here.) + */ + msgLength = getCopyDataMessage(conn); + if (msgLength < 0) + return -1; /* end-of-copy or error */ + if (msgLength == 0) + return 0; /* no data yet */ + + /* + * Move data from libpq's buffer to the caller's. In the case where a + * prior call found the caller's buffer too small, we use + * conn->copy_already_done to remember how much of the row was already + * returned to the caller. + */ + conn->inCursor += conn->copy_already_done; + avail = msgLength - 4 - conn->copy_already_done; + if (avail <= bufsize) + { + /* Able to consume the whole message */ + memcpy(buffer, &conn->inBuffer[conn->inCursor], avail); + /* Mark message consumed */ + conn->inStart = conn->inCursor + avail; + /* Reset state for next time */ + conn->copy_already_done = 0; + return avail; + } + else + { + /* We must return a partial message */ + memcpy(buffer, &conn->inBuffer[conn->inCursor], bufsize); + /* The message is NOT consumed from libpq's buffer */ + conn->copy_already_done += bufsize; + return bufsize; + } +} + +/* + * PQendcopy + * + * See fe-exec.c for documentation. + */ +int +pqEndcopy3(PGconn *conn) +{ + PGresult *result; + + if (conn->asyncStatus != PGASYNC_COPY_IN && + conn->asyncStatus != PGASYNC_COPY_OUT && + conn->asyncStatus != PGASYNC_COPY_BOTH) + { + libpq_append_conn_error(conn, "no COPY in progress"); + return 1; + } + + /* Send the CopyDone message if needed */ + if (conn->asyncStatus == PGASYNC_COPY_IN || + conn->asyncStatus == PGASYNC_COPY_BOTH) + { + if (pqPutMsgStart('c', conn) < 0 || + pqPutMsgEnd(conn) < 0) + return 1; + + /* + * If we sent the COPY command in extended-query mode, we must issue a + * Sync as well. + */ + if (conn->cmd_queue_head && + conn->cmd_queue_head->queryclass != PGQUERY_SIMPLE) + { + if (pqPutMsgStart('S', conn) < 0 || + pqPutMsgEnd(conn) < 0) + return 1; + } + } + + /* + * make sure no data is waiting to be sent, abort if we are non-blocking + * and the flush fails + */ + if (pqFlush(conn) && pqIsnonblocking(conn)) + return 1; + + /* Return to active duty */ + conn->asyncStatus = PGASYNC_BUSY; + + /* + * Non blocking connections may have to abort at this point. If everyone + * played the game there should be no problem, but in error scenarios the + * expected messages may not have arrived yet. (We are assuming that the + * backend's packetizing will ensure that CommandComplete arrives along + * with the CopyDone; are there corner cases where that doesn't happen?) + */ + if (pqIsnonblocking(conn) && PQisBusy(conn)) + return 1; + + /* Wait for the completion response */ + result = PQgetResult(conn); + + /* Expecting a successful result */ + if (result && result->resultStatus == PGRES_COMMAND_OK) + { + PQclear(result); + return 0; + } + + /* + * Trouble. For backwards-compatibility reasons, we issue the error + * message as if it were a notice (would be nice to get rid of this + * silliness, but too many apps probably don't handle errors from + * PQendcopy reasonably). Note that the app can still obtain the error + * status from the PGconn object. + */ + if (conn->errorMessage.len > 0) + { + /* We have to strip the trailing newline ... pain in neck... */ + char svLast = conn->errorMessage.data[conn->errorMessage.len - 1]; + + if (svLast == '\n') + conn->errorMessage.data[conn->errorMessage.len - 1] = '\0'; + pqInternalNotice(&conn->noticeHooks, "%s", conn->errorMessage.data); + conn->errorMessage.data[conn->errorMessage.len - 1] = svLast; + } + + PQclear(result); + + return 1; +} + + +/* + * PQfn - Send a function call to the POSTGRES backend. + * + * See fe-exec.c for documentation. + */ +PGresult * +pqFunctionCall3(PGconn *conn, Oid fnid, + int *result_buf, int *actual_result_len, + int result_is_int, + const PQArgBlock *args, int nargs) +{ + bool needInput = false; + ExecStatusType status = PGRES_FATAL_ERROR; + char id; + int msgLength; + int avail; + int i; + + /* already validated by PQfn */ + Assert(conn->pipelineStatus == PQ_PIPELINE_OFF); + + /* PQfn already validated connection state */ + + if (pqPutMsgStart('F', conn) < 0 || /* function call msg */ + pqPutInt(fnid, 4, conn) < 0 || /* function id */ + pqPutInt(1, 2, conn) < 0 || /* # of format codes */ + pqPutInt(1, 2, conn) < 0 || /* format code: BINARY */ + pqPutInt(nargs, 2, conn) < 0) /* # of args */ + { + /* error message should be set up already */ + return NULL; + } + + for (i = 0; i < nargs; ++i) + { /* len.int4 + contents */ + if (pqPutInt(args[i].len, 4, conn)) + return NULL; + if (args[i].len == -1) + continue; /* it's NULL */ + + if (args[i].isint) + { + if (pqPutInt(args[i].u.integer, args[i].len, conn)) + return NULL; + } + else + { + if (pqPutnchar((char *) args[i].u.ptr, args[i].len, conn)) + return NULL; + } + } + + if (pqPutInt(1, 2, conn) < 0) /* result format code: BINARY */ + return NULL; + + if (pqPutMsgEnd(conn) < 0 || + pqFlush(conn)) + return NULL; + + for (;;) + { + if (needInput) + { + /* Wait for some data to arrive (or for the channel to close) */ + if (pqWait(true, false, conn) || + pqReadData(conn) < 0) + break; + } + + /* + * Scan the message. If we run out of data, loop around to try again. + */ + needInput = true; + + conn->inCursor = conn->inStart; + if (pqGetc(&id, conn)) + continue; + if (pqGetInt(&msgLength, 4, conn)) + continue; + + /* + * Try to validate message type/length here. A length less than 4 is + * definitely broken. Large lengths should only be believed for a few + * message types. + */ + if (msgLength < 4) + { + handleSyncLoss(conn, id, msgLength); + break; + } + if (msgLength > 30000 && !VALID_LONG_MESSAGE_TYPE(id)) + { + handleSyncLoss(conn, id, msgLength); + break; + } + + /* + * Can't process if message body isn't all here yet. + */ + msgLength -= 4; + avail = conn->inEnd - conn->inCursor; + if (avail < msgLength) + { + /* + * Before looping, enlarge the input buffer if needed to hold the + * whole message. See notes in parseInput. + */ + if (pqCheckInBufferSpace(conn->inCursor + (size_t) msgLength, + conn)) + { + /* + * XXX add some better recovery code... plan is to skip over + * the message using its length, then report an error. For the + * moment, just treat this like loss of sync (which indeed it + * might be!) + */ + handleSyncLoss(conn, id, msgLength); + break; + } + continue; + } + + /* + * We should see V or E response to the command, but might get N + * and/or A notices first. We also need to swallow the final Z before + * returning. + */ + switch (id) + { + case 'V': /* function result */ + if (pqGetInt(actual_result_len, 4, conn)) + continue; + if (*actual_result_len != -1) + { + if (result_is_int) + { + if (pqGetInt(result_buf, *actual_result_len, conn)) + continue; + } + else + { + if (pqGetnchar((char *) result_buf, + *actual_result_len, + conn)) + continue; + } + } + /* correctly finished function result message */ + status = PGRES_COMMAND_OK; + break; + case 'E': /* error return */ + if (pqGetErrorNotice3(conn, true)) + continue; + status = PGRES_FATAL_ERROR; + break; + case 'A': /* notify message */ + /* handle notify and go back to processing return values */ + if (getNotify(conn)) + continue; + break; + case 'N': /* notice */ + /* handle notice and go back to processing return values */ + if (pqGetErrorNotice3(conn, false)) + continue; + break; + case 'Z': /* backend is ready for new query */ + if (getReadyForQuery(conn)) + continue; + /* consume the message and exit */ + conn->inStart += 5 + msgLength; + + /* + * If we already have a result object (probably an error), use + * that. Otherwise, if we saw a function result message, + * report COMMAND_OK. Otherwise, the backend violated the + * protocol, so complain. + */ + if (!pgHavePendingResult(conn)) + { + if (status == PGRES_COMMAND_OK) + { + conn->result = PQmakeEmptyPGresult(conn, status); + if (!conn->result) + { + libpq_append_conn_error(conn, "out of memory"); + pqSaveErrorResult(conn); + } + } + else + { + libpq_append_conn_error(conn, "protocol error: no function result"); + pqSaveErrorResult(conn); + } + } + return pqPrepareAsyncResult(conn); + case 'S': /* parameter status */ + if (getParameterStatus(conn)) + continue; + break; + default: + /* The backend violates the protocol. */ + libpq_append_conn_error(conn, "protocol error: id=0x%x", id); + pqSaveErrorResult(conn); + /* trust the specified message length as what to skip */ + conn->inStart += 5 + msgLength; + return pqPrepareAsyncResult(conn); + } + + /* trace server-to-client message */ + if (conn->Pfdebug) + pqTraceOutputMessage(conn, conn->inBuffer + conn->inStart, false); + + /* Completed this message, keep going */ + /* trust the specified message length as what to skip */ + conn->inStart += 5 + msgLength; + needInput = false; + } + + /* + * We fall out of the loop only upon failing to read data. + * conn->errorMessage has been set by pqWait or pqReadData. We want to + * append it to any already-received error message. + */ + pqSaveErrorResult(conn); + return pqPrepareAsyncResult(conn); +} + + +/* + * Construct startup packet + * + * Returns a malloc'd packet buffer, or NULL if out of memory + */ +char * +pqBuildStartupPacket3(PGconn *conn, int *packetlen, + const PQEnvironmentOption *options) +{ + char *startpacket; + + *packetlen = build_startup_packet(conn, NULL, options); + startpacket = (char *) malloc(*packetlen); + if (!startpacket) + return NULL; + *packetlen = build_startup_packet(conn, startpacket, options); + return startpacket; +} + +/* + * Build a startup packet given a filled-in PGconn structure. + * + * We need to figure out how much space is needed, then fill it in. + * To avoid duplicate logic, this routine is called twice: the first time + * (with packet == NULL) just counts the space needed, the second time + * (with packet == allocated space) fills it in. Return value is the number + * of bytes used. + */ +static int +build_startup_packet(const PGconn *conn, char *packet, + const PQEnvironmentOption *options) +{ + int packet_len = 0; + const PQEnvironmentOption *next_eo; + const char *val; + + /* Protocol version comes first. */ + if (packet) + { + ProtocolVersion pv = pg_hton32(conn->pversion); + + memcpy(packet + packet_len, &pv, sizeof(ProtocolVersion)); + } + packet_len += sizeof(ProtocolVersion); + + /* Add user name, database name, options */ + +#define ADD_STARTUP_OPTION(optname, optval) \ + do { \ + if (packet) \ + strcpy(packet + packet_len, optname); \ + packet_len += strlen(optname) + 1; \ + if (packet) \ + strcpy(packet + packet_len, optval); \ + packet_len += strlen(optval) + 1; \ + } while(0) + + if (conn->pguser && conn->pguser[0]) + ADD_STARTUP_OPTION("user", conn->pguser); + if (conn->dbName && conn->dbName[0]) + ADD_STARTUP_OPTION("database", conn->dbName); + if (conn->replication && conn->replication[0]) + ADD_STARTUP_OPTION("replication", conn->replication); + if (conn->pgoptions && conn->pgoptions[0]) + ADD_STARTUP_OPTION("options", conn->pgoptions); + if (conn->send_appname) + { + /* Use appname if present, otherwise use fallback */ + val = conn->appname ? conn->appname : conn->fbappname; + if (val && val[0]) + ADD_STARTUP_OPTION("application_name", val); + } + + if (conn->client_encoding_initial && conn->client_encoding_initial[0]) + ADD_STARTUP_OPTION("client_encoding", conn->client_encoding_initial); + + /* Add any environment-driven GUC settings needed */ + for (next_eo = options; next_eo->envName; next_eo++) + { + if ((val = getenv(next_eo->envName)) != NULL) + { + if (pg_strcasecmp(val, "default") != 0) + ADD_STARTUP_OPTION(next_eo->pgName, val); + } + } + + /* Add trailing terminator */ + if (packet) + packet[packet_len] = '\0'; + packet_len++; + + return packet_len; +} |