/*------------------------------------------------------------------------- * * fe-protocol2.c * functions that are specific to frontend/backend protocol version 2 * * Portions Copyright (c) 1996-2016, 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 #include #include "libpq-fe.h" #include "libpq-int.h" #ifdef WIN32 #include "win32.h" #else #include #include #ifdef HAVE_NETINET_TCP_H #include #endif #include #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; /* * 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); 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 = htonl(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; }