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Diffstat (limited to 'libpq/fe-exec.c')
| -rw-r--r-- | libpq/fe-exec.c | 3764 |
1 files changed, 3764 insertions, 0 deletions
diff --git a/libpq/fe-exec.c b/libpq/fe-exec.c new file mode 100644 index 0000000..87ff565 --- /dev/null +++ b/libpq/fe-exec.c @@ -0,0 +1,3764 @@ +/*------------------------------------------------------------------------- + * + * fe-exec.c + * functions related to sending a query down to the backend + * + * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * + * IDENTIFICATION + * src/interfaces/libpq/fe-exec.c + * + *------------------------------------------------------------------------- + */ +#include "postgres_fe.h" + +#include <ctype.h> +#include <fcntl.h> + +#include "libpq-fe.h" +#include "libpq-int.h" + +#include "mb/pg_wchar.h" + +#ifdef WIN32 +#include "win32.h" +#else +#include <unistd.h> +#endif + +/* keep this in same order as ExecStatusType in libpq-fe.h */ +char *const pgresStatus[] = { + "PGRES_EMPTY_QUERY", + "PGRES_COMMAND_OK", + "PGRES_TUPLES_OK", + "PGRES_COPY_OUT", + "PGRES_COPY_IN", + "PGRES_BAD_RESPONSE", + "PGRES_NONFATAL_ERROR", + "PGRES_FATAL_ERROR", + "PGRES_COPY_BOTH", + "PGRES_SINGLE_TUPLE" +}; + +/* + * static state needed by PQescapeString and PQescapeBytea; initialize to + * values that result in backward-compatible behavior + */ +static int static_client_encoding = PG_SQL_ASCII; +static bool static_std_strings = false; + + +static PGEvent *dupEvents(PGEvent *events, int count); +static bool pqAddTuple(PGresult *res, PGresAttValue *tup); +static bool PQsendQueryStart(PGconn *conn); +static int PQsendQueryGuts(PGconn *conn, + const char *command, + const char *stmtName, + int nParams, + const Oid *paramTypes, + const char *const * paramValues, + const int *paramLengths, + const int *paramFormats, + int resultFormat); +static void parseInput(PGconn *conn); +static PGresult *getCopyResult(PGconn *conn, ExecStatusType copytype); +static bool PQexecStart(PGconn *conn); +static PGresult *PQexecFinish(PGconn *conn); +static int PQsendDescribe(PGconn *conn, char desc_type, + const char *desc_target); +static int check_field_number(const PGresult *res, int field_num); + + +/* ---------------- + * Space management for PGresult. + * + * Formerly, libpq did a separate malloc() for each field of each tuple + * returned by a query. This was remarkably expensive --- malloc/free + * consumed a sizable part of the application's runtime. And there is + * no real need to keep track of the fields separately, since they will + * all be freed together when the PGresult is released. So now, we grab + * large blocks of storage from malloc and allocate space for query data + * within these blocks, using a trivially simple allocator. This reduces + * the number of malloc/free calls dramatically, and it also avoids + * fragmentation of the malloc storage arena. + * The PGresult structure itself is still malloc'd separately. We could + * combine it with the first allocation block, but that would waste space + * for the common case that no extra storage is actually needed (that is, + * the SQL command did not return tuples). + * + * We also malloc the top-level array of tuple pointers separately, because + * we need to be able to enlarge it via realloc, and our trivial space + * allocator doesn't handle that effectively. (Too bad the FE/BE protocol + * doesn't tell us up front how many tuples will be returned.) + * All other subsidiary storage for a PGresult is kept in PGresult_data blocks + * of size PGRESULT_DATA_BLOCKSIZE. The overhead at the start of each block + * is just a link to the next one, if any. Free-space management info is + * kept in the owning PGresult. + * A query returning a small amount of data will thus require three malloc + * calls: one for the PGresult, one for the tuples pointer array, and one + * PGresult_data block. + * + * Only the most recently allocated PGresult_data block is a candidate to + * have more stuff added to it --- any extra space left over in older blocks + * is wasted. We could be smarter and search the whole chain, but the point + * here is to be simple and fast. Typical applications do not keep a PGresult + * around very long anyway, so some wasted space within one is not a problem. + * + * Tuning constants for the space allocator are: + * PGRESULT_DATA_BLOCKSIZE: size of a standard allocation block, in bytes + * PGRESULT_ALIGN_BOUNDARY: assumed alignment requirement for binary data + * PGRESULT_SEP_ALLOC_THRESHOLD: objects bigger than this are given separate + * blocks, instead of being crammed into a regular allocation block. + * Requirements for correct function are: + * PGRESULT_ALIGN_BOUNDARY must be a multiple of the alignment requirements + * of all machine data types. (Currently this is set from configure + * tests, so it should be OK automatically.) + * PGRESULT_SEP_ALLOC_THRESHOLD + PGRESULT_BLOCK_OVERHEAD <= + * PGRESULT_DATA_BLOCKSIZE + * pqResultAlloc assumes an object smaller than the threshold will fit + * in a new block. + * The amount of space wasted at the end of a block could be as much as + * PGRESULT_SEP_ALLOC_THRESHOLD, so it doesn't pay to make that too large. + * ---------------- + */ + +#define PGRESULT_DATA_BLOCKSIZE 2048 +#define PGRESULT_ALIGN_BOUNDARY MAXIMUM_ALIGNOF /* from configure */ +#define PGRESULT_BLOCK_OVERHEAD Max(sizeof(PGresult_data), PGRESULT_ALIGN_BOUNDARY) +#define PGRESULT_SEP_ALLOC_THRESHOLD (PGRESULT_DATA_BLOCKSIZE / 2) + + +/* + * PQmakeEmptyPGresult + * returns a newly allocated, initialized PGresult with given status. + * If conn is not NULL and status indicates an error, the conn's + * errorMessage is copied. Also, any PGEvents are copied from the conn. + */ +PGresult * +PQmakeEmptyPGresult(PGconn *conn, ExecStatusType status) +{ + PGresult *result; + + result = (PGresult *) malloc(sizeof(PGresult)); + if (!result) + return NULL; + + result->ntups = 0; + result->numAttributes = 0; + result->attDescs = NULL; + result->tuples = NULL; + result->tupArrSize = 0; + result->numParameters = 0; + result->paramDescs = NULL; + result->resultStatus = status; + result->cmdStatus[0] = '\0'; + result->binary = 0; + result->events = NULL; + result->nEvents = 0; + result->errMsg = NULL; + result->errFields = NULL; + result->errQuery = NULL; + result->null_field[0] = '\0'; + result->curBlock = NULL; + result->curOffset = 0; + result->spaceLeft = 0; + + if (conn) + { + /* copy connection data we might need for operations on PGresult */ + result->noticeHooks = conn->noticeHooks; + result->client_encoding = conn->client_encoding; + + /* consider copying conn's errorMessage */ + switch (status) + { + case PGRES_EMPTY_QUERY: + case PGRES_COMMAND_OK: + case PGRES_TUPLES_OK: + case PGRES_COPY_OUT: + case PGRES_COPY_IN: + case PGRES_COPY_BOTH: + case PGRES_SINGLE_TUPLE: + /* non-error cases */ + break; + default: + pqSetResultError(result, conn->errorMessage.data); + break; + } + + /* copy events last; result must be valid if we need to PQclear */ + if (conn->nEvents > 0) + { + result->events = dupEvents(conn->events, conn->nEvents); + if (!result->events) + { + PQclear(result); + return NULL; + } + result->nEvents = conn->nEvents; + } + } + else + { + /* defaults... */ + result->noticeHooks.noticeRec = NULL; + result->noticeHooks.noticeRecArg = NULL; + result->noticeHooks.noticeProc = NULL; + result->noticeHooks.noticeProcArg = NULL; + result->client_encoding = PG_SQL_ASCII; + } + + return result; +} + +/* + * PQsetResultAttrs + * + * Set the attributes for a given result. This function fails if there are + * already attributes contained in the provided result. The call is + * ignored if numAttributes is zero or attDescs is NULL. If the + * function fails, it returns zero. If the function succeeds, it + * returns a non-zero value. + */ +int +PQsetResultAttrs(PGresult *res, int numAttributes, PGresAttDesc *attDescs) +{ + int i; + + /* If attrs already exist, they cannot be overwritten. */ + if (!res || res->numAttributes > 0) + return FALSE; + + /* ignore no-op request */ + if (numAttributes <= 0 || !attDescs) + return TRUE; + + res->attDescs = (PGresAttDesc *) + PQresultAlloc(res, numAttributes * sizeof(PGresAttDesc)); + + if (!res->attDescs) + return FALSE; + + res->numAttributes = numAttributes; + memcpy(res->attDescs, attDescs, numAttributes * sizeof(PGresAttDesc)); + + /* deep-copy the attribute names, and determine format */ + res->binary = 1; + for (i = 0; i < res->numAttributes; i++) + { + if (res->attDescs[i].name) + res->attDescs[i].name = pqResultStrdup(res, res->attDescs[i].name); + else + res->attDescs[i].name = res->null_field; + + if (!res->attDescs[i].name) + return FALSE; + + if (res->attDescs[i].format == 0) + res->binary = 0; + } + + return TRUE; +} + +/* + * PQcopyResult + * + * Returns a deep copy of the provided 'src' PGresult, which cannot be NULL. + * The 'flags' argument controls which portions of the result will or will + * NOT be copied. The created result is always put into the + * PGRES_TUPLES_OK status. The source result error message is not copied, + * although cmdStatus is. + * + * To set custom attributes, use PQsetResultAttrs. That function requires + * that there are no attrs contained in the result, so to use that + * function you cannot use the PG_COPYRES_ATTRS or PG_COPYRES_TUPLES + * options with this function. + * + * Options: + * PG_COPYRES_ATTRS - Copy the source result's attributes + * + * PG_COPYRES_TUPLES - Copy the source result's tuples. This implies + * copying the attrs, seeing how the attrs are needed by the tuples. + * + * PG_COPYRES_EVENTS - Copy the source result's events. + * + * PG_COPYRES_NOTICEHOOKS - Copy the source result's notice hooks. + */ +PGresult * +PQcopyResult(const PGresult *src, int flags) +{ + PGresult *dest; + int i; + + if (!src) + return NULL; + + dest = PQmakeEmptyPGresult(NULL, PGRES_TUPLES_OK); + if (!dest) + return NULL; + + /* Always copy these over. Is cmdStatus really useful here? */ + dest->client_encoding = src->client_encoding; + strcpy(dest->cmdStatus, src->cmdStatus); + + /* Wants attrs? */ + if (flags & (PG_COPYRES_ATTRS | PG_COPYRES_TUPLES)) + { + if (!PQsetResultAttrs(dest, src->numAttributes, src->attDescs)) + { + PQclear(dest); + return NULL; + } + } + + /* Wants to copy tuples? */ + if (flags & PG_COPYRES_TUPLES) + { + int tup, + field; + + for (tup = 0; tup < src->ntups; tup++) + { + for (field = 0; field < src->numAttributes; field++) + { + if (!PQsetvalue(dest, tup, field, + src->tuples[tup][field].value, + src->tuples[tup][field].len)) + { + PQclear(dest); + return NULL; + } + } + } + } + + /* Wants to copy notice hooks? */ + if (flags & PG_COPYRES_NOTICEHOOKS) + dest->noticeHooks = src->noticeHooks; + + /* Wants to copy PGEvents? */ + if ((flags & PG_COPYRES_EVENTS) && src->nEvents > 0) + { + dest->events = dupEvents(src->events, src->nEvents); + if (!dest->events) + { + PQclear(dest); + return NULL; + } + dest->nEvents = src->nEvents; + } + + /* Okay, trigger PGEVT_RESULTCOPY event */ + for (i = 0; i < dest->nEvents; i++) + { + if (src->events[i].resultInitialized) + { + PGEventResultCopy evt; + + evt.src = src; + evt.dest = dest; + if (!dest->events[i].proc(PGEVT_RESULTCOPY, &evt, + dest->events[i].passThrough)) + { + PQclear(dest); + return NULL; + } + dest->events[i].resultInitialized = TRUE; + } + } + + return dest; +} + +/* + * Copy an array of PGEvents (with no extra space for more). + * Does not duplicate the event instance data, sets this to NULL. + * Also, the resultInitialized flags are all cleared. + */ +static PGEvent * +dupEvents(PGEvent *events, int count) +{ + PGEvent *newEvents; + int i; + + if (!events || count <= 0) + return NULL; + + newEvents = (PGEvent *) malloc(count * sizeof(PGEvent)); + if (!newEvents) + return NULL; + + for (i = 0; i < count; i++) + { + newEvents[i].proc = events[i].proc; + newEvents[i].passThrough = events[i].passThrough; + newEvents[i].data = NULL; + newEvents[i].resultInitialized = FALSE; + newEvents[i].name = strdup(events[i].name); + if (!newEvents[i].name) + { + while (--i >= 0) + free(newEvents[i].name); + free(newEvents); + return NULL; + } + } + + return newEvents; +} + + +/* + * Sets the value for a tuple field. The tup_num must be less than or + * equal to PQntuples(res). If it is equal, a new tuple is created and + * added to the result. + * Returns a non-zero value for success and zero for failure. + */ +int +PQsetvalue(PGresult *res, int tup_num, int field_num, char *value, int len) +{ + PGresAttValue *attval; + + if (!check_field_number(res, field_num)) + return FALSE; + + /* Invalid tup_num, must be <= ntups */ + if (tup_num < 0 || tup_num > res->ntups) + return FALSE; + + /* need to allocate a new tuple? */ + if (tup_num == res->ntups) + { + PGresAttValue *tup; + int i; + + tup = (PGresAttValue *) + pqResultAlloc(res, res->numAttributes * sizeof(PGresAttValue), + TRUE); + + if (!tup) + return FALSE; + + /* initialize each column to NULL */ + for (i = 0; i < res->numAttributes; i++) + { + tup[i].len = NULL_LEN; + tup[i].value = res->null_field; + } + + /* add it to the array */ + if (!pqAddTuple(res, tup)) + return FALSE; + } + + attval = &res->tuples[tup_num][field_num]; + + /* treat either NULL_LEN or NULL value pointer as a NULL field */ + if (len == NULL_LEN || value == NULL) + { + attval->len = NULL_LEN; + attval->value = res->null_field; + } + else if (len <= 0) + { + attval->len = 0; + attval->value = res->null_field; + } + else + { + attval->value = (char *) pqResultAlloc(res, len + 1, TRUE); + if (!attval->value) + return FALSE; + attval->len = len; + memcpy(attval->value, value, len); + attval->value[len] = '\0'; + } + + return TRUE; +} + +/* + * pqResultAlloc - exported routine to allocate local storage in a PGresult. + * + * We force all such allocations to be maxaligned, since we don't know + * whether the value might be binary. + */ +void * +PQresultAlloc(PGresult *res, size_t nBytes) +{ + return pqResultAlloc(res, nBytes, TRUE); +} + +/* + * pqResultAlloc - + * Allocate subsidiary storage for a PGresult. + * + * nBytes is the amount of space needed for the object. + * If isBinary is true, we assume that we need to align the object on + * a machine allocation boundary. + * If isBinary is false, we assume the object is a char string and can + * be allocated on any byte boundary. + */ +void * +pqResultAlloc(PGresult *res, size_t nBytes, bool isBinary) +{ + char *space; + PGresult_data *block; + + if (!res) + return NULL; + + if (nBytes <= 0) + return res->null_field; + + /* + * If alignment is needed, round up the current position to an alignment + * boundary. + */ + if (isBinary) + { + int offset = res->curOffset % PGRESULT_ALIGN_BOUNDARY; + + if (offset) + { + res->curOffset += PGRESULT_ALIGN_BOUNDARY - offset; + res->spaceLeft -= PGRESULT_ALIGN_BOUNDARY - offset; + } + } + + /* If there's enough space in the current block, no problem. */ + if (nBytes <= (size_t) res->spaceLeft) + { + space = res->curBlock->space + res->curOffset; + res->curOffset += nBytes; + res->spaceLeft -= nBytes; + return space; + } + + /* + * If the requested object is very large, give it its own block; this + * avoids wasting what might be most of the current block to start a new + * block. (We'd have to special-case requests bigger than the block size + * anyway.) The object is always given binary alignment in this case. + */ + if (nBytes >= PGRESULT_SEP_ALLOC_THRESHOLD) + { + block = (PGresult_data *) malloc(nBytes + PGRESULT_BLOCK_OVERHEAD); + if (!block) + return NULL; + space = block->space + PGRESULT_BLOCK_OVERHEAD; + if (res->curBlock) + { + /* + * Tuck special block below the active block, so that we don't + * have to waste the free space in the active block. + */ + block->next = res->curBlock->next; + res->curBlock->next = block; + } + else + { + /* Must set up the new block as the first active block. */ + block->next = NULL; + res->curBlock = block; + res->spaceLeft = 0; /* be sure it's marked full */ + } + return space; + } + + /* Otherwise, start a new block. */ + block = (PGresult_data *) malloc(PGRESULT_DATA_BLOCKSIZE); + if (!block) + return NULL; + block->next = res->curBlock; + res->curBlock = block; + if (isBinary) + { + /* object needs full alignment */ + res->curOffset = PGRESULT_BLOCK_OVERHEAD; + res->spaceLeft = PGRESULT_DATA_BLOCKSIZE - PGRESULT_BLOCK_OVERHEAD; + } + else + { + /* we can cram it right after the overhead pointer */ + res->curOffset = sizeof(PGresult_data); + res->spaceLeft = PGRESULT_DATA_BLOCKSIZE - sizeof(PGresult_data); + } + + space = block->space + res->curOffset; + res->curOffset += nBytes; + res->spaceLeft -= nBytes; + return space; +} + +/* + * pqResultStrdup - + * Like strdup, but the space is subsidiary PGresult space. + */ +char * +pqResultStrdup(PGresult *res, const char *str) +{ + char *space = (char *) pqResultAlloc(res, strlen(str) + 1, FALSE); + + if (space) + strcpy(space, str); + return space; +} + +/* + * pqSetResultError - + * assign a new error message to a PGresult + */ +void +pqSetResultError(PGresult *res, const char *msg) +{ + if (!res) + return; + if (msg && *msg) + res->errMsg = pqResultStrdup(res, msg); + else + res->errMsg = NULL; +} + +/* + * pqCatenateResultError - + * concatenate a new error message to the one already in a PGresult + */ +void +pqCatenateResultError(PGresult *res, const char *msg) +{ + PQExpBufferData errorBuf; + + if (!res || !msg) + return; + initPQExpBuffer(&errorBuf); + if (res->errMsg) + appendPQExpBufferStr(&errorBuf, res->errMsg); + appendPQExpBufferStr(&errorBuf, msg); + pqSetResultError(res, errorBuf.data); + termPQExpBuffer(&errorBuf); +} + +/* + * PQclear - + * free's the memory associated with a PGresult + */ +void +PQclear(PGresult *res) +{ + PGresult_data *block; + int i; + + if (!res) + return; + + for (i = 0; i < res->nEvents; i++) + { + /* only send DESTROY to successfully-initialized event procs */ + if (res->events[i].resultInitialized) + { + PGEventResultDestroy evt; + + evt.result = res; + (void) res->events[i].proc(PGEVT_RESULTDESTROY, &evt, + res->events[i].passThrough); + } + free(res->events[i].name); + } + + if (res->events) + free(res->events); + + /* Free all the subsidiary blocks */ + while ((block = res->curBlock) != NULL) + { + res->curBlock = block->next; + free(block); + } + + /* Free the top-level tuple pointer array */ + if (res->tuples) + free(res->tuples); + + /* zero out the pointer fields to catch programming errors */ + res->attDescs = NULL; + res->tuples = NULL; + res->paramDescs = NULL; + res->errFields = NULL; + res->events = NULL; + res->nEvents = 0; + /* res->curBlock was zeroed out earlier */ + + /* Free the PGresult structure itself */ + free(res); +} + +/* + * Handy subroutine to deallocate any partially constructed async result. + * + * Any "next" result gets cleared too. + */ +void +pqClearAsyncResult(PGconn *conn) +{ + if (conn->result) + PQclear(conn->result); + conn->result = NULL; + if (conn->next_result) + PQclear(conn->next_result); + conn->next_result = NULL; +} + +/* + * This subroutine deletes any existing async result, sets conn->result + * to a PGresult with status PGRES_FATAL_ERROR, and stores the current + * contents of conn->errorMessage into that result. It differs from a + * plain call on PQmakeEmptyPGresult() in that if there is already an + * async result with status PGRES_FATAL_ERROR, the current error message + * is APPENDED to the old error message instead of replacing it. This + * behavior lets us report multiple error conditions properly, if necessary. + * (An example where this is needed is when the backend sends an 'E' message + * and immediately closes the connection --- we want to report both the + * backend error and the connection closure error.) + */ +void +pqSaveErrorResult(PGconn *conn) +{ + /* + * If no old async result, just let PQmakeEmptyPGresult make one. Likewise + * if old result is not an error message. + */ + if (conn->result == NULL || + conn->result->resultStatus != PGRES_FATAL_ERROR || + conn->result->errMsg == NULL) + { + pqClearAsyncResult(conn); + conn->result = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR); + } + else + { + /* Else, concatenate error message to existing async result. */ + pqCatenateResultError(conn->result, conn->errorMessage.data); + } +} + +/* + * This subroutine prepares an async result object for return to the caller. + * If there is not already an async result object, build an error object + * using whatever is in conn->errorMessage. In any case, clear the async + * result storage and make sure PQerrorMessage will agree with the result's + * error string. + */ +PGresult * +pqPrepareAsyncResult(PGconn *conn) +{ + PGresult *res; + + /* + * conn->result is the PGresult to return. If it is NULL (which probably + * shouldn't happen) we assume there is an appropriate error message in + * conn->errorMessage. + */ + res = conn->result; + if (!res) + res = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR); + else + { + /* + * Make sure PQerrorMessage agrees with result; it could be different + * if we have concatenated messages. + */ + resetPQExpBuffer(&conn->errorMessage); + appendPQExpBufferStr(&conn->errorMessage, + PQresultErrorMessage(res)); + } + + /* + * Replace conn->result with next_result, if any. In the normal case + * there isn't a next result and we're just dropping ownership of the + * current result. In single-row mode this restores the situation to what + * it was before we created the current single-row result. + */ + conn->result = conn->next_result; + conn->next_result = NULL; + + return res; +} + +/* + * pqInternalNotice - produce an internally-generated notice message + * + * A format string and optional arguments can be passed. Note that we do + * libpq_gettext() here, so callers need not. + * + * The supplied text is taken as primary message (ie., it should not include + * a trailing newline, and should not be more than one line). + */ +void +pqInternalNotice(const PGNoticeHooks *hooks, const char *fmt,...) +{ + char msgBuf[1024]; + va_list args; + PGresult *res; + + if (hooks->noticeRec == NULL) + return; /* nobody home to receive notice? */ + + /* Format the message */ + va_start(args, fmt); + vsnprintf(msgBuf, sizeof(msgBuf), libpq_gettext(fmt), args); + va_end(args); + msgBuf[sizeof(msgBuf) - 1] = '\0'; /* make real sure it's terminated */ + + /* Make a PGresult to pass to the notice receiver */ + res = PQmakeEmptyPGresult(NULL, PGRES_NONFATAL_ERROR); + if (!res) + return; + res->noticeHooks = *hooks; + + /* + * Set up fields of notice. + */ + pqSaveMessageField(res, PG_DIAG_MESSAGE_PRIMARY, msgBuf); + pqSaveMessageField(res, PG_DIAG_SEVERITY, libpq_gettext("NOTICE")); + pqSaveMessageField(res, PG_DIAG_SEVERITY_NONLOCALIZED, "NOTICE"); + /* XXX should provide a SQLSTATE too? */ + + /* + * Result text is always just the primary message + newline. If we can't + * allocate it, don't bother invoking the receiver. + */ + res->errMsg = (char *) pqResultAlloc(res, strlen(msgBuf) + 2, FALSE); + if (res->errMsg) + { + sprintf(res->errMsg, "%s\n", msgBuf); + + /* + * Pass to receiver, then free it. + */ + (*res->noticeHooks.noticeRec) (res->noticeHooks.noticeRecArg, res); + } + PQclear(res); +} + +/* + * pqAddTuple + * add a row pointer to the PGresult structure, growing it if necessary + * Returns TRUE if OK, FALSE if not enough memory to add the row + */ +static bool +pqAddTuple(PGresult *res, PGresAttValue *tup) +{ + if (res->ntups >= res->tupArrSize) + { + /* + * Try to grow the array. + * + * We can use realloc because shallow copying of the structure is + * okay. Note that the first time through, res->tuples is NULL. While + * ANSI says that realloc() should act like malloc() in that case, + * some old C libraries (like SunOS 4.1.x) coredump instead. On + * failure realloc is supposed to return NULL without damaging the + * existing allocation. Note that the positions beyond res->ntups are + * garbage, not necessarily NULL. + */ + int newSize = (res->tupArrSize > 0) ? res->tupArrSize * 2 : 128; + PGresAttValue **newTuples; + + if (res->tuples == NULL) + newTuples = (PGresAttValue **) + malloc(newSize * sizeof(PGresAttValue *)); + else + newTuples = (PGresAttValue **) + realloc(res->tuples, newSize * sizeof(PGresAttValue *)); + if (!newTuples) + return FALSE; /* malloc or realloc failed */ + res->tupArrSize = newSize; + res->tuples = newTuples; + } + res->tuples[res->ntups] = tup; + res->ntups++; + return TRUE; +} + +/* + * pqSaveMessageField - save one field of an error or notice message + */ +void +pqSaveMessageField(PGresult *res, char code, const char *value) +{ + PGMessageField *pfield; + + pfield = (PGMessageField *) + pqResultAlloc(res, + offsetof(PGMessageField, contents) + + strlen(value) + 1, + TRUE); + if (!pfield) + return; /* out of memory? */ + pfield->code = code; + strcpy(pfield->contents, value); + pfield->next = res->errFields; + res->errFields = pfield; +} + +/* + * pqSaveParameterStatus - remember parameter status sent by backend + */ +void +pqSaveParameterStatus(PGconn *conn, const char *name, const char *value) +{ + pgParameterStatus *pstatus; + pgParameterStatus *prev; + + if (conn->Pfdebug) + fprintf(conn->Pfdebug, "pqSaveParameterStatus: '%s' = '%s'\n", + name, value); + + /* + * Forget any old information about the parameter + */ + for (pstatus = conn->pstatus, prev = NULL; + pstatus != NULL; + prev = pstatus, pstatus = pstatus->next) + { + if (strcmp(pstatus->name, name) == 0) + { + if (prev) + prev->next = pstatus->next; + else + conn->pstatus = pstatus->next; + free(pstatus); /* frees name and value strings too */ + break; + } + } + + /* + * Store new info as a single malloc block + */ + pstatus = (pgParameterStatus *) malloc(sizeof(pgParameterStatus) + + strlen(name) +strlen(value) + 2); + if (pstatus) + { + char *ptr; + + ptr = ((char *) pstatus) + sizeof(pgParameterStatus); + pstatus->name = ptr; + strcpy(ptr, name); + ptr += strlen(name) + 1; + pstatus->value = ptr; + strcpy(ptr, value); + pstatus->next = conn->pstatus; + conn->pstatus = pstatus; + } + + /* + * Special hacks: remember client_encoding and + * standard_conforming_strings, and convert server version to a numeric + * form. We keep the first two of these in static variables as well, so + * that PQescapeString and PQescapeBytea can behave somewhat sanely (at + * least in single-connection-using programs). + */ + if (strcmp(name, "client_encoding") == 0) + { + conn->client_encoding = pg_char_to_encoding(value); + /* if we don't recognize the encoding name, fall back to SQL_ASCII */ + if (conn->client_encoding < 0) + conn->client_encoding = PG_SQL_ASCII; + static_client_encoding = conn->client_encoding; + } + else if (strcmp(name, "standard_conforming_strings") == 0) + { + conn->std_strings = (strcmp(value, "on") == 0); + static_std_strings = conn->std_strings; + } + else if (strcmp(name, "server_version") == 0) + { + int cnt; + int vmaj, + vmin, + vrev; + + cnt = sscanf(value, "%d.%d.%d", &vmaj, &vmin, &vrev); + + if (cnt == 3) + { + /* old style, e.g. 9.6.1 */ + conn->sversion = (100 * vmaj + vmin) * 100 + vrev; + } + else if (cnt == 2) + { + if (vmaj >= 10) + { + /* new style, e.g. 10.1 */ + conn->sversion = 100 * 100 * vmaj + vmin; + } + else + { + /* old style without minor version, e.g. 9.6devel */ + conn->sversion = (100 * vmaj + vmin) * 100; + } + } + else if (cnt == 1) + { + /* new style without minor version, e.g. 10devel */ + conn->sversion = 100 * 100 * vmaj; + } + else + conn->sversion = 0; /* unknown */ + } +} + + +/* + * pqRowProcessor + * Add the received row to the current async result (conn->result). + * Returns 1 if OK, 0 if error occurred. + * + * On error, *errmsgp can be set to an error string to be returned. + * If it is left NULL, the error is presumed to be "out of memory". + * + * In single-row mode, we create a new result holding just the current row, + * stashing the previous result in conn->next_result so that it becomes + * active again after pqPrepareAsyncResult(). This allows the result metadata + * (column descriptions) to be carried forward to each result row. + */ +int +pqRowProcessor(PGconn *conn, const char **errmsgp) +{ + PGresult *res = conn->result; + int nfields = res->numAttributes; + const PGdataValue *columns = conn->rowBuf; + PGresAttValue *tup; + int i; + + /* + * In single-row mode, make a new PGresult that will hold just this one + * row; the original conn->result is left unchanged so that it can be used + * again as the template for future rows. + */ + if (conn->singleRowMode) + { + /* Copy everything that should be in the result at this point */ + res = PQcopyResult(res, + PG_COPYRES_ATTRS | PG_COPYRES_EVENTS | + PG_COPYRES_NOTICEHOOKS); + if (!res) + return 0; + } + + /* + * Basically we just allocate space in the PGresult for each field and + * copy the data over. + * + * Note: on malloc failure, we return 0 leaving *errmsgp still NULL, which + * caller will take to mean "out of memory". This is preferable to trying + * to set up such a message here, because evidently there's not enough + * memory for gettext() to do anything. + */ + tup = (PGresAttValue *) + pqResultAlloc(res, nfields * sizeof(PGresAttValue), TRUE); + if (tup == NULL) + goto fail; + + for (i = 0; i < nfields; i++) + { + int clen = columns[i].len; + + if (clen < 0) + { + /* null field */ + tup[i].len = NULL_LEN; + tup[i].value = res->null_field; + } + else + { + bool isbinary = (res->attDescs[i].format != 0); + char *val; + + val = (char *) pqResultAlloc(res, clen + 1, isbinary); + if (val == NULL) + goto fail; + + /* copy and zero-terminate the data (even if it's binary) */ + memcpy(val, columns[i].value, clen); + val[clen] = '\0'; + + tup[i].len = clen; + tup[i].value = val; + } + } + + /* And add the tuple to the PGresult's tuple array */ + if (!pqAddTuple(res, tup)) + goto fail; + + /* + * Success. In single-row mode, make the result available to the client + * immediately. + */ + if (conn->singleRowMode) + { + /* Change result status to special single-row value */ + res->resultStatus = PGRES_SINGLE_TUPLE; + /* Stash old result for re-use later */ + conn->next_result = conn->result; + conn->result = res; + /* And mark the result ready to return */ + conn->asyncStatus = PGASYNC_READY; + } + + return 1; + +fail: + /* release locally allocated PGresult, if we made one */ + if (res != conn->result) + PQclear(res); + return 0; +} + + +/* + * PQsendQuery + * Submit a query, but don't wait for it to finish + * + * Returns: 1 if successfully submitted + * 0 if error (conn->errorMessage is set) + */ +int +PQsendQuery(PGconn *conn, const char *query) +{ + if (!PQsendQueryStart(conn)) + return 0; + + /* check the argument */ + if (!query) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("command string is a null pointer\n")); + return 0; + } + + /* construct the outgoing Query message */ + if (pqPutMsgStart('Q', false, conn) < 0 || + pqPuts(query, conn) < 0 || + pqPutMsgEnd(conn) < 0) + { + pqHandleSendFailure(conn); + return 0; + } + + /* remember we are using simple query protocol */ + conn->queryclass = PGQUERY_SIMPLE; + + /* and remember the query text too, if possible */ + /* if insufficient memory, last_query just winds up NULL */ + if (conn->last_query) + free(conn->last_query); + conn->last_query = strdup(query); + + /* + * Give the data a push. In nonblock mode, don't complain if we're unable + * to send it all; PQgetResult() will do any additional flushing needed. + */ + if (pqFlush(conn) < 0) + { + pqHandleSendFailure(conn); + return 0; + } + + /* OK, it's launched! */ + conn->asyncStatus = PGASYNC_BUSY; + return 1; +} + +/* + * PQsendQueryParams + * Like PQsendQuery, but use protocol 3.0 so we can pass parameters + */ +int +PQsendQueryParams(PGconn *conn, + const char *command, + int nParams, + const Oid *paramTypes, + const char *const * paramValues, + const int *paramLengths, + const int *paramFormats, + int resultFormat) +{ + if (!PQsendQueryStart(conn)) + return 0; + + /* check the arguments */ + if (!command) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("command string is a null pointer\n")); + return 0; + } + if (nParams < 0 || nParams > 65535) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("number of parameters must be between 0 and 65535\n")); + return 0; + } + + return PQsendQueryGuts(conn, + command, + "", /* use unnamed statement */ + nParams, + paramTypes, + paramValues, + paramLengths, + paramFormats, + resultFormat); +} + +/* + * PQsendPrepare + * Submit a Parse message, but don't wait for it to finish + * + * Returns: 1 if successfully submitted + * 0 if error (conn->errorMessage is set) + */ +int +PQsendPrepare(PGconn *conn, + const char *stmtName, const char *query, + int nParams, const Oid *paramTypes) +{ + if (!PQsendQueryStart(conn)) + return 0; + + /* check the arguments */ + if (!stmtName) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("statement name is a null pointer\n")); + return 0; + } + if (!query) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("command string is a null pointer\n")); + return 0; + } + if (nParams < 0 || nParams > 65535) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("number of parameters must be between 0 and 65535\n")); + return 0; + } + + /* This isn't gonna work on a 2.0 server */ + if (PG_PROTOCOL_MAJOR(conn->pversion) < 3) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("function requires at least protocol version 3.0\n")); + return 0; + } + + /* construct the Parse message */ + if (pqPutMsgStart('P', false, conn) < 0 || + pqPuts(stmtName, conn) < 0 || + pqPuts(query, conn) < 0) + goto sendFailed; + + if (nParams > 0 && paramTypes) + { + int i; + + if (pqPutInt(nParams, 2, conn) < 0) + goto sendFailed; + for (i = 0; i < nParams; i++) + { + if (pqPutInt(paramTypes[i], 4, conn) < 0) + goto sendFailed; + } + } + else + { + if (pqPutInt(0, 2, conn) < 0) + goto sendFailed; + } + if (pqPutMsgEnd(conn) < 0) + goto sendFailed; + + /* construct the Sync message */ + if (pqPutMsgStart('S', false, conn) < 0 || + pqPutMsgEnd(conn) < 0) + goto sendFailed; + + /* remember we are doing just a Parse */ + conn->queryclass = PGQUERY_PREPARE; + + /* and remember the query text too, if possible */ + /* if insufficient memory, last_query just winds up NULL */ + if (conn->last_query) + free(conn->last_query); + conn->last_query = strdup(query); + + /* + * Give the data a push. In nonblock mode, don't complain if we're unable + * to send it all; PQgetResult() will do any additional flushing needed. + */ + if (pqFlush(conn) < 0) + goto sendFailed; + + /* OK, it's launched! */ + conn->asyncStatus = PGASYNC_BUSY; + return 1; + +sendFailed: + pqHandleSendFailure(conn); + return 0; +} + +/* + * PQsendQueryPrepared + * Like PQsendQuery, but execute a previously prepared statement, + * using protocol 3.0 so we can pass parameters + */ +int +PQsendQueryPrepared(PGconn *conn, + const char *stmtName, + int nParams, + const char *const * paramValues, + const int *paramLengths, + const int *paramFormats, + int resultFormat) +{ + if (!PQsendQueryStart(conn)) + return 0; + + /* check the arguments */ + if (!stmtName) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("statement name is a null pointer\n")); + return 0; + } + if (nParams < 0 || nParams > 65535) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("number of parameters must be between 0 and 65535\n")); + return 0; + } + + return PQsendQueryGuts(conn, + NULL, /* no command to parse */ + stmtName, + nParams, + NULL, /* no param types */ + paramValues, + paramLengths, + paramFormats, + resultFormat); +} + +/* + * Common startup code for PQsendQuery and sibling routines + */ +static bool +PQsendQueryStart(PGconn *conn) +{ + if (!conn) + return false; + + /* clear the error string */ + resetPQExpBuffer(&conn->errorMessage); + + /* Don't try to send if we know there's no live connection. */ + if (conn->status != CONNECTION_OK) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("no connection to the server\n")); + return false; + } + /* Can't send while already busy, either. */ + if (conn->asyncStatus != PGASYNC_IDLE) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("another command is already in progress\n")); + return false; + } + + /* initialize async result-accumulation state */ + pqClearAsyncResult(conn); + + /* reset single-row processing mode */ + conn->singleRowMode = false; + + /* ready to send command message */ + return true; +} + +/* + * PQsendQueryGuts + * Common code for protocol-3.0 query sending + * PQsendQueryStart should be done already + * + * command may be NULL to indicate we use an already-prepared statement + */ +static int +PQsendQueryGuts(PGconn *conn, + const char *command, + const char *stmtName, + int nParams, + const Oid *paramTypes, + const char *const * paramValues, + const int *paramLengths, + const int *paramFormats, + int resultFormat) +{ + int i; + + /* This isn't gonna work on a 2.0 server */ + if (PG_PROTOCOL_MAJOR(conn->pversion) < 3) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("function requires at least protocol version 3.0\n")); + return 0; + } + + /* + * We will send Parse (if needed), Bind, Describe Portal, Execute, Sync, + * using specified statement name and the unnamed portal. + */ + + if (command) + { + /* construct the Parse message */ + if (pqPutMsgStart('P', false, conn) < 0 || + pqPuts(stmtName, conn) < 0 || + pqPuts(command, conn) < 0) + goto sendFailed; + if (nParams > 0 && paramTypes) + { + if (pqPutInt(nParams, 2, conn) < 0) + goto sendFailed; + for (i = 0; i < nParams; i++) + { + if (pqPutInt(paramTypes[i], 4, conn) < 0) + goto sendFailed; + } + } + else + { + if (pqPutInt(0, 2, conn) < 0) + goto sendFailed; + } + if (pqPutMsgEnd(conn) < 0) + goto sendFailed; + } + + /* Construct the Bind message */ + if (pqPutMsgStart('B', false, conn) < 0 || + pqPuts("", conn) < 0 || + pqPuts(stmtName, conn) < 0) + goto sendFailed; + + /* Send parameter formats */ + if (nParams > 0 && paramFormats) + { + if (pqPutInt(nParams, 2, conn) < 0) + goto sendFailed; + for (i = 0; i < nParams; i++) + { + if (pqPutInt(paramFormats[i], 2, conn) < 0) + goto sendFailed; + } + } + else + { + if (pqPutInt(0, 2, conn) < 0) + goto sendFailed; + } + + if (pqPutInt(nParams, 2, conn) < 0) + goto sendFailed; + + /* Send parameters */ + for (i = 0; i < nParams; i++) + { + if (paramValues && paramValues[i]) + { + int nbytes; + + if (paramFormats && paramFormats[i] != 0) + { + /* binary parameter */ + if (paramLengths) + nbytes = paramLengths[i]; + else + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("length must be given for binary parameter\n")); + goto sendFailed; + } + } + else + { + /* text parameter, do not use paramLengths */ + nbytes = strlen(paramValues[i]); + } + if (pqPutInt(nbytes, 4, conn) < 0 || + pqPutnchar(paramValues[i], nbytes, conn) < 0) + goto sendFailed; + } + else + { + /* take the param as NULL */ + if (pqPutInt(-1, 4, conn) < 0) + goto sendFailed; + } + } + if (pqPutInt(1, 2, conn) < 0 || + pqPutInt(resultFormat, 2, conn)) + goto sendFailed; + if (pqPutMsgEnd(conn) < 0) + goto sendFailed; + + /* construct the Describe Portal message */ + if (pqPutMsgStart('D', false, conn) < 0 || + pqPutc('P', conn) < 0 || + pqPuts("", conn) < 0 || + pqPutMsgEnd(conn) < 0) + goto sendFailed; + + /* construct the Execute message */ + if (pqPutMsgStart('E', false, conn) < 0 || + pqPuts("", conn) < 0 || + pqPutInt(0, 4, conn) < 0 || + pqPutMsgEnd(conn) < 0) + goto sendFailed; + + /* construct the Sync message */ + if (pqPutMsgStart('S', false, conn) < 0 || + pqPutMsgEnd(conn) < 0) + goto sendFailed; + + /* remember we are using extended query protocol */ + conn->queryclass = PGQUERY_EXTENDED; + + /* and remember the query text too, if possible */ + /* if insufficient memory, last_query just winds up NULL */ + if (conn->last_query) + free(conn->last_query); + if (command) + conn->last_query = strdup(command); + else + conn->last_query = NULL; + + /* + * Give the data a push. In nonblock mode, don't complain if we're unable + * to send it all; PQgetResult() will do any additional flushing needed. + */ + if (pqFlush(conn) < 0) + goto sendFailed; + + /* OK, it's launched! */ + conn->asyncStatus = PGASYNC_BUSY; + return 1; + +sendFailed: + pqHandleSendFailure(conn); + return 0; +} + +/* + * pqHandleSendFailure: try to clean up after failure to send command. + * + * Primarily, what we want to accomplish here is to process any ERROR or + * NOTICE messages that the backend might have sent just before it died. + * Since we're in IDLE state, all such messages will get sent to the notice + * processor. + * + * NOTE: this routine should only be called in PGASYNC_IDLE state. + */ +void +pqHandleSendFailure(PGconn *conn) +{ + /* + * Accept and parse any available input data, ignoring I/O errors. Note + * that if pqReadData decides the backend has closed the channel, it will + * close our side of the socket --- that's just what we want here. + */ + while (pqReadData(conn) > 0) + parseInput(conn); + + /* + * Be sure to parse available input messages even if we read no data. + * (Note: calling parseInput within the above loop isn't really necessary, + * but it prevents buffer bloat if there's a lot of data available.) + */ + parseInput(conn); +} + +/* + * Select row-by-row processing mode + */ +int +PQsetSingleRowMode(PGconn *conn) +{ + /* + * Only allow setting the flag when we have launched a query and not yet + * received any results. + */ + if (!conn) + return 0; + if (conn->asyncStatus != PGASYNC_BUSY) + return 0; + if (conn->queryclass != PGQUERY_SIMPLE && + conn->queryclass != PGQUERY_EXTENDED) + return 0; + if (conn->result) + return 0; + + /* OK, set flag */ + conn->singleRowMode = true; + return 1; +} + +/* + * Consume any available input from the backend + * 0 return: some kind of trouble + * 1 return: no problem + */ +int +PQconsumeInput(PGconn *conn) +{ + if (!conn) + return 0; + + /* + * for non-blocking connections try to flush the send-queue, otherwise we + * may never get a response for something that may not have already been + * sent because it's in our write buffer! + */ + if (pqIsnonblocking(conn)) + { + if (pqFlush(conn) < 0) + return 0; + } + + /* + * Load more data, if available. We do this no matter what state we are + * in, since we are probably getting called because the application wants + * to get rid of a read-select condition. Note that we will NOT block + * waiting for more input. + */ + if (pqReadData(conn) < 0) + return 0; + + /* Parsing of the data waits till later. */ + return 1; +} + + +/* + * 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. + */ +static void +parseInput(PGconn *conn) +{ + if (PG_PROTOCOL_MAJOR(conn->pversion) >= 3) + pqParseInput3(conn); + else + pqParseInput2(conn); +} + +/* + * PQisBusy + * Return TRUE if PQgetResult would block waiting for input. + */ + +int +PQisBusy(PGconn *conn) +{ + if (!conn) + return FALSE; + + /* Parse any available data, if our state permits. */ + parseInput(conn); + + /* PQgetResult will return immediately in all states except BUSY. */ + return conn->asyncStatus == PGASYNC_BUSY; +} + + +/* + * PQgetResult + * Get the next PGresult produced by a query. Returns NULL if no + * query work remains or an error has occurred (e.g. out of + * memory). + */ + +PGresult * +PQgetResult(PGconn *conn) +{ + PGresult *res; + + if (!conn) + return NULL; + + /* Parse any available data, if our state permits. */ + parseInput(conn); + + /* If not ready to return something, block until we are. */ + while (conn->asyncStatus == PGASYNC_BUSY) + { + int flushResult; + + /* + * If data remains unsent, send it. Else we might be waiting for the + * result of a command the backend hasn't even got yet. + */ + while ((flushResult = pqFlush(conn)) > 0) + { + if (pqWait(FALSE, TRUE, conn)) + { + flushResult = -1; + break; + } + } + + /* Wait for some more data, and load it. */ + if (flushResult || + pqWait(TRUE, FALSE, conn) || + pqReadData(conn) < 0) + { + /* + * conn->errorMessage has been set by pqWait or pqReadData. We + * want to append it to any already-received error message. + */ + pqSaveErrorResult(conn); + conn->asyncStatus = PGASYNC_IDLE; + return pqPrepareAsyncResult(conn); + } + + /* Parse it. */ + parseInput(conn); + } + + /* Return the appropriate thing. */ + switch (conn->asyncStatus) + { + case PGASYNC_IDLE: + res = NULL; /* query is complete */ + break; + case PGASYNC_READY: + res = pqPrepareAsyncResult(conn); + /* Set the state back to BUSY, allowing parsing to proceed. */ + conn->asyncStatus = PGASYNC_BUSY; + break; + case PGASYNC_COPY_IN: + res = getCopyResult(conn, PGRES_COPY_IN); + break; + case PGASYNC_COPY_OUT: + res = getCopyResult(conn, PGRES_COPY_OUT); + break; + case PGASYNC_COPY_BOTH: + res = getCopyResult(conn, PGRES_COPY_BOTH); + break; + default: + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("unexpected asyncStatus: %d\n"), + (int) conn->asyncStatus); + res = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR); + break; + } + + if (res) + { + int i; + + for (i = 0; i < res->nEvents; i++) + { + PGEventResultCreate evt; + + evt.conn = conn; + evt.result = res; + if (!res->events[i].proc(PGEVT_RESULTCREATE, &evt, + res->events[i].passThrough)) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("PGEventProc \"%s\" failed during PGEVT_RESULTCREATE event\n"), + res->events[i].name); + pqSetResultError(res, conn->errorMessage.data); + res->resultStatus = PGRES_FATAL_ERROR; + break; + } + res->events[i].resultInitialized = TRUE; + } + } + + return res; +} + +/* + * getCopyResult + * Helper for PQgetResult: generate result for COPY-in-progress cases + */ +static PGresult * +getCopyResult(PGconn *conn, ExecStatusType copytype) +{ + /* + * If the server connection has been lost, don't pretend everything is + * hunky-dory; instead return a PGRES_FATAL_ERROR result, and reset the + * asyncStatus to idle (corresponding to what we'd do if we'd detected I/O + * error in the earlier steps in PQgetResult). The text returned in the + * result is whatever is in conn->errorMessage; we hope that was filled + * with something relevant when the lost connection was detected. + */ + if (conn->status != CONNECTION_OK) + { + pqSaveErrorResult(conn); + conn->asyncStatus = PGASYNC_IDLE; + return pqPrepareAsyncResult(conn); + } + + /* If we have an async result for the COPY, return that */ + if (conn->result && conn->result->resultStatus == copytype) + return pqPrepareAsyncResult(conn); + + /* Otherwise, invent a suitable PGresult */ + return PQmakeEmptyPGresult(conn, copytype); +} + + +/* + * PQexec + * send a query to the backend and package up the result in a PGresult + * + * If the query was not even sent, return NULL; conn->errorMessage is set to + * a relevant message. + * If the query was sent, a new PGresult is returned (which could indicate + * either success or failure). + * The user is responsible for freeing the PGresult via PQclear() + * when done with it. + */ +PGresult * +PQexec(PGconn *conn, const char *query) +{ + if (!PQexecStart(conn)) + return NULL; + if (!PQsendQuery(conn, query)) + return NULL; + return PQexecFinish(conn); +} + +/* + * PQexecParams + * Like PQexec, but use protocol 3.0 so we can pass parameters + */ +PGresult * +PQexecParams(PGconn *conn, + const char *command, + int nParams, + const Oid *paramTypes, + const char *const * paramValues, + const int *paramLengths, + const int *paramFormats, + int resultFormat) +{ + if (!PQexecStart(conn)) + return NULL; + if (!PQsendQueryParams(conn, command, + nParams, paramTypes, paramValues, paramLengths, + paramFormats, resultFormat)) + return NULL; + return PQexecFinish(conn); +} + +/* + * PQprepare + * Creates a prepared statement by issuing a v3.0 parse message. + * + * If the query was not even sent, return NULL; conn->errorMessage is set to + * a relevant message. + * If the query was sent, a new PGresult is returned (which could indicate + * either success or failure). + * The user is responsible for freeing the PGresult via PQclear() + * when done with it. + */ +PGresult * +PQprepare(PGconn *conn, + const char *stmtName, const char *query, + int nParams, const Oid *paramTypes) +{ + if (!PQexecStart(conn)) + return NULL; + if (!PQsendPrepare(conn, stmtName, query, nParams, paramTypes)) + return NULL; + return PQexecFinish(conn); +} + +/* + * PQexecPrepared + * Like PQexec, but execute a previously prepared statement, + * using protocol 3.0 so we can pass parameters + */ +PGresult * +PQexecPrepared(PGconn *conn, + const char *stmtName, + int nParams, + const char *const * paramValues, + const int *paramLengths, + const int *paramFormats, + int resultFormat) +{ + if (!PQexecStart(conn)) + return NULL; + if (!PQsendQueryPrepared(conn, stmtName, + nParams, paramValues, paramLengths, + paramFormats, resultFormat)) + return NULL; + return PQexecFinish(conn); +} + +/* + * Common code for PQexec and sibling routines: prepare to send command + */ +static bool +PQexecStart(PGconn *conn) +{ + PGresult *result; + + if (!conn) + return false; + + /* + * Silently discard any prior query result that application didn't eat. + * This is probably poor design, but it's here for backward compatibility. + */ + while ((result = PQgetResult(conn)) != NULL) + { + ExecStatusType resultStatus = result->resultStatus; + + PQclear(result); /* only need its status */ + if (resultStatus == PGRES_COPY_IN) + { + if (PG_PROTOCOL_MAJOR(conn->pversion) >= 3) + { + /* In protocol 3, we can get out of a COPY IN state */ + if (PQputCopyEnd(conn, + libpq_gettext("COPY terminated by new PQexec")) < 0) + return false; + /* keep waiting to swallow the copy's failure message */ + } + else + { + /* In older protocols we have to punt */ + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("COPY IN state must be terminated first\n")); + return false; + } + } + else if (resultStatus == PGRES_COPY_OUT) + { + if (PG_PROTOCOL_MAJOR(conn->pversion) >= 3) + { + /* + * In protocol 3, we can get out of a COPY OUT state: we just + * switch back to BUSY and allow the remaining COPY data to be + * dropped on the floor. + */ + conn->asyncStatus = PGASYNC_BUSY; + /* keep waiting to swallow the copy's completion message */ + } + else + { + /* In older protocols we have to punt */ + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("COPY OUT state must be terminated first\n")); + return false; + } + } + else if (resultStatus == PGRES_COPY_BOTH) + { + /* We don't allow PQexec during COPY BOTH */ + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("PQexec not allowed during COPY BOTH\n")); + return false; + } + /* check for loss of connection, too */ + if (conn->status == CONNECTION_BAD) + return false; + } + + /* OK to send a command */ + return true; +} + +/* + * Common code for PQexec and sibling routines: wait for command result + */ +static PGresult * +PQexecFinish(PGconn *conn) +{ + PGresult *result; + PGresult *lastResult; + + /* + * For backwards compatibility, return the last result if there are more + * than one --- but merge error messages if we get more than one error + * result. + * + * We have to stop if we see copy in/out/both, however. We will resume + * parsing after application performs the data transfer. + * + * Also stop if the connection is lost (else we'll loop infinitely). + */ + lastResult = NULL; + while ((result = PQgetResult(conn)) != NULL) + { + if (lastResult) + { + if (lastResult->resultStatus == PGRES_FATAL_ERROR && + result->resultStatus == PGRES_FATAL_ERROR) + { + pqCatenateResultError(lastResult, result->errMsg); + PQclear(result); + result = lastResult; + + /* + * Make sure PQerrorMessage agrees with concatenated result + */ + resetPQExpBuffer(&conn->errorMessage); + appendPQExpBufferStr(&conn->errorMessage, result->errMsg); + } + else + PQclear(lastResult); + } + lastResult = result; + if (result->resultStatus == PGRES_COPY_IN || + result->resultStatus == PGRES_COPY_OUT || + result->resultStatus == PGRES_COPY_BOTH || + conn->status == CONNECTION_BAD) + break; + } + + return lastResult; +} + +/* + * PQdescribePrepared + * Obtain information about a previously prepared statement + * + * If the query was not even sent, return NULL; conn->errorMessage is set to + * a relevant message. + * If the query was sent, a new PGresult is returned (which could indicate + * either success or failure). On success, the PGresult contains status + * PGRES_COMMAND_OK, and its parameter and column-heading fields describe + * the statement's inputs and outputs respectively. + * The user is responsible for freeing the PGresult via PQclear() + * when done with it. + */ +PGresult * +PQdescribePrepared(PGconn *conn, const char *stmt) +{ + if (!PQexecStart(conn)) + return NULL; + if (!PQsendDescribe(conn, 'S', stmt)) + return NULL; + return PQexecFinish(conn); +} + +/* + * PQdescribePortal + * Obtain information about a previously created portal + * + * This is much like PQdescribePrepared, except that no parameter info is + * returned. Note that at the moment, libpq doesn't really expose portals + * to the client; but this can be used with a portal created by a SQL + * DECLARE CURSOR command. + */ +PGresult * +PQdescribePortal(PGconn *conn, const char *portal) +{ + if (!PQexecStart(conn)) + return NULL; + if (!PQsendDescribe(conn, 'P', portal)) + return NULL; + return PQexecFinish(conn); +} + +/* + * PQsendDescribePrepared + * Submit a Describe Statement command, but don't wait for it to finish + * + * Returns: 1 if successfully submitted + * 0 if error (conn->errorMessage is set) + */ +int +PQsendDescribePrepared(PGconn *conn, const char *stmt) +{ + return PQsendDescribe(conn, 'S', stmt); +} + +/* + * PQsendDescribePortal + * Submit a Describe Portal command, but don't wait for it to finish + * + * Returns: 1 if successfully submitted + * 0 if error (conn->errorMessage is set) + */ +int +PQsendDescribePortal(PGconn *conn, const char *portal) +{ + return PQsendDescribe(conn, 'P', portal); +} + +/* + * PQsendDescribe + * Common code to send a Describe command + * + * Available options for desc_type are + * 'S' to describe a prepared statement; or + * 'P' to describe a portal. + * Returns 1 on success and 0 on failure. + */ +static int +PQsendDescribe(PGconn *conn, char desc_type, const char *desc_target) +{ + /* Treat null desc_target as empty string */ + if (!desc_target) + desc_target = ""; + + if (!PQsendQueryStart(conn)) + return 0; + + /* This isn't gonna work on a 2.0 server */ + if (PG_PROTOCOL_MAJOR(conn->pversion) < 3) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("function requires at least protocol version 3.0\n")); + return 0; + } + + /* construct the Describe message */ + if (pqPutMsgStart('D', false, conn) < 0 || + pqPutc(desc_type, conn) < 0 || + pqPuts(desc_target, conn) < 0 || + pqPutMsgEnd(conn) < 0) + goto sendFailed; + + /* construct the Sync message */ + if (pqPutMsgStart('S', false, conn) < 0 || + pqPutMsgEnd(conn) < 0) + goto sendFailed; + + /* remember we are doing a Describe */ + conn->queryclass = PGQUERY_DESCRIBE; + + /* reset last-query string (not relevant now) */ + if (conn->last_query) + { + free(conn->last_query); + conn->last_query = NULL; + } + + /* + * Give the data a push. In nonblock mode, don't complain if we're unable + * to send it all; PQgetResult() will do any additional flushing needed. + */ + if (pqFlush(conn) < 0) + goto sendFailed; + + /* OK, it's launched! */ + conn->asyncStatus = PGASYNC_BUSY; + return 1; + +sendFailed: + pqHandleSendFailure(conn); + return 0; +} + +/* + * PQnotifies + * returns a PGnotify* structure of the latest async notification + * that has not yet been handled + * + * returns NULL, if there is currently + * no unhandled async notification from the backend + * + * the CALLER is responsible for FREE'ing the structure returned + */ +PGnotify * +PQnotifies(PGconn *conn) +{ + PGnotify *event; + + if (!conn) + return NULL; + + /* Parse any available data to see if we can extract NOTIFY messages. */ + parseInput(conn); + + event = conn->notifyHead; + if (event) + { + conn->notifyHead = event->next; + if (!conn->notifyHead) + conn->notifyTail = NULL; + event->next = NULL; /* don't let app see the internal state */ + } + return event; +} + +/* + * PQputCopyData - send some data to the backend during COPY IN or COPY BOTH + * + * Returns 1 if successful, 0 if data could not be sent (only possible + * in nonblock mode), or -1 if an error occurs. + */ +int +PQputCopyData(PGconn *conn, const char *buffer, int nbytes) +{ + if (!conn) + return -1; + if (conn->asyncStatus != PGASYNC_COPY_IN && + conn->asyncStatus != PGASYNC_COPY_BOTH) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("no COPY in progress\n")); + return -1; + } + + /* + * Process any NOTICE or NOTIFY messages that might be pending in the + * input buffer. Since the server might generate many notices during the + * COPY, we want to clean those out reasonably promptly to prevent + * indefinite expansion of the input buffer. (Note: the actual read of + * input data into the input buffer happens down inside pqSendSome, but + * it's not authorized to get rid of the data again.) + */ + parseInput(conn); + + if (nbytes > 0) + { + /* + * Try to flush any previously sent data in preference to growing the + * output buffer. If we can't enlarge the buffer enough to hold the + * data, return 0 in the nonblock case, else hard error. (For + * simplicity, always assume 5 bytes of overhead even in protocol 2.0 + * case.) + */ + if ((conn->outBufSize - conn->outCount - 5) < nbytes) + { + if (pqFlush(conn) < 0) + return -1; + if (pqCheckOutBufferSpace(conn->outCount + 5 + (size_t) nbytes, + conn)) + return pqIsnonblocking(conn) ? 0 : -1; + } + /* Send the data (too simple to delegate to fe-protocol files) */ + if (PG_PROTOCOL_MAJOR(conn->pversion) >= 3) + { + if (pqPutMsgStart('d', false, conn) < 0 || + pqPutnchar(buffer, nbytes, conn) < 0 || + pqPutMsgEnd(conn) < 0) + return -1; + } + else + { + if (pqPutMsgStart(0, false, conn) < 0 || + pqPutnchar(buffer, nbytes, conn) < 0 || + pqPutMsgEnd(conn) < 0) + return -1; + } + } + return 1; +} + +/* + * PQputCopyEnd - send EOF indication to the backend during COPY IN + * + * After calling this, use PQgetResult() to check command completion status. + * + * Returns 1 if successful, 0 if data could not be sent (only possible + * in nonblock mode), or -1 if an error occurs. + */ +int +PQputCopyEnd(PGconn *conn, const char *errormsg) +{ + if (!conn) + return -1; + if (conn->asyncStatus != PGASYNC_COPY_IN && + conn->asyncStatus != PGASYNC_COPY_BOTH) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("no COPY in progress\n")); + return -1; + } + + /* + * Send the COPY END indicator. This is simple enough that we don't + * bother delegating it to the fe-protocol files. + */ + if (PG_PROTOCOL_MAJOR(conn->pversion) >= 3) + { + if (errormsg) + { + /* Send COPY FAIL */ + if (pqPutMsgStart('f', false, conn) < 0 || + pqPuts(errormsg, conn) < 0 || + pqPutMsgEnd(conn) < 0) + return -1; + } + else + { + /* Send COPY DONE */ + if (pqPutMsgStart('c', false, 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->queryclass != PGQUERY_SIMPLE) + { + if (pqPutMsgStart('S', false, conn) < 0 || + pqPutMsgEnd(conn) < 0) + return -1; + } + } + else + { + if (errormsg) + { + /* Ooops, no way to do this in 2.0 */ + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("function requires at least protocol version 3.0\n")); + return -1; + } + else + { + /* Send old-style end-of-data marker */ + if (pqPutMsgStart(0, false, conn) < 0 || + pqPutnchar("\\.\n", 3, conn) < 0 || + pqPutMsgEnd(conn) < 0) + return -1; + } + } + + /* Return to active duty */ + if (conn->asyncStatus == PGASYNC_COPY_BOTH) + conn->asyncStatus = PGASYNC_COPY_OUT; + else + conn->asyncStatus = PGASYNC_BUSY; + resetPQExpBuffer(&conn->errorMessage); + + /* Try to flush data */ + if (pqFlush(conn) < 0) + return -1; + + return 1; +} + +/* + * 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 +PQgetCopyData(PGconn *conn, char **buffer, int async) +{ + *buffer = NULL; /* for all failure cases */ + if (!conn) + return -2; + if (conn->asyncStatus != PGASYNC_COPY_OUT && + conn->asyncStatus != PGASYNC_COPY_BOTH) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("no COPY in progress\n")); + return -2; + } + if (PG_PROTOCOL_MAJOR(conn->pversion) >= 3) + return pqGetCopyData3(conn, buffer, async); + else + return pqGetCopyData2(conn, buffer, async); +} + +/* + * PQgetline - gets a newline-terminated string from the backend. + * + * Chiefly here so that applications can use "COPY <rel> to stdout" + * and read the output string. Returns a null-terminated string in s. + * + * XXX this routine is now deprecated, because it can't handle binary data. + * If called during a COPY BINARY we return EOF. + * + * PQgetline reads up to maxlen-1 characters (like fgets(3)) but strips + * the terminating \n (like gets(3)). + * + * CAUTION: the caller is responsible for detecting the end-of-copy signal + * (a line containing just "\.") when using this routine. + * + * RETURNS: + * EOF if error (eg, invalid arguments are given) + * 0 if EOL is reached (i.e., \n has been read) + * (this is required for backward-compatibility -- this + * routine used to always return EOF or 0, assuming that + * the line ended within maxlen bytes.) + * 1 in other cases (i.e., the buffer was filled before \n is reached) + */ +int +PQgetline(PGconn *conn, char *s, int maxlen) +{ + if (!s || maxlen <= 0) + return EOF; + *s = '\0'; + /* maxlen must be at least 3 to hold the \. terminator! */ + if (maxlen < 3) + return EOF; + + if (!conn) + return EOF; + + if (PG_PROTOCOL_MAJOR(conn->pversion) >= 3) + return pqGetline3(conn, s, maxlen); + else + return pqGetline2(conn, s, maxlen); +} + +/* + * PQgetlineAsync - gets a COPY data row without blocking. + * + * This routine is for applications that want to do "COPY <rel> to stdout" + * asynchronously, that is without blocking. Having issued the COPY command + * and gotten a PGRES_COPY_OUT response, the app should call PQconsumeInput + * and this routine until the end-of-data signal is detected. Unlike + * PQgetline, this routine takes responsibility for detecting end-of-data. + * + * On each call, PQgetlineAsync will return data if a complete data row + * is available in libpq's input buffer. Otherwise, no data is returned + * until the rest of the row arrives. + * + * If -1 is returned, the end-of-data signal has been recognized (and removed + * from libpq's input buffer). The caller *must* next call PQendcopy and + * then return to normal processing. + * + * RETURNS: + * -1 if the end-of-copy-data marker has been recognized + * 0 if no data is available + * >0 the number of bytes returned. + * + * The data returned will not extend beyond a data-row boundary. If possible + * a whole row will be returned at one time. But if the buffer offered by + * the caller is too small to hold a row sent by the backend, then a partial + * data row will be returned. In text mode this can be detected by testing + * whether the last returned byte is '\n' or not. + * + * The returned data is *not* null-terminated. + */ + +int +PQgetlineAsync(PGconn *conn, char *buffer, int bufsize) +{ + if (!conn) + return -1; + + if (PG_PROTOCOL_MAJOR(conn->pversion) >= 3) + return pqGetlineAsync3(conn, buffer, bufsize); + else + return pqGetlineAsync2(conn, buffer, bufsize); +} + +/* + * PQputline -- sends a string to the backend during COPY IN. + * Returns 0 if OK, EOF if not. + * + * This is deprecated primarily because the return convention doesn't allow + * caller to tell the difference between a hard error and a nonblock-mode + * send failure. + */ +int +PQputline(PGconn *conn, const char *s) +{ + return PQputnbytes(conn, s, strlen(s)); +} + +/* + * PQputnbytes -- like PQputline, but buffer need not be null-terminated. + * Returns 0 if OK, EOF if not. + */ +int +PQputnbytes(PGconn *conn, const char *buffer, int nbytes) +{ + if (PQputCopyData(conn, buffer, nbytes) > 0) + return 0; + else + return EOF; +} + +/* + * PQendcopy + * After completing the data transfer portion of a copy in/out, + * the application must call this routine to finish the command protocol. + * + * When using protocol 3.0 this is deprecated; it's cleaner to use PQgetResult + * to get the transfer status. Note however that when using 2.0 protocol, + * recovering from a copy failure often requires a PQreset. PQendcopy will + * take care of that, PQgetResult won't. + * + * RETURNS: + * 0 on success + * 1 on failure + */ +int +PQendcopy(PGconn *conn) +{ + if (!conn) + return 0; + + if (PG_PROTOCOL_MAJOR(conn->pversion) >= 3) + return pqEndcopy3(conn); + else + return pqEndcopy2(conn); +} + + +/* ---------------- + * PQfn - Send a function call to the POSTGRES backend. + * + * conn : backend connection + * fnid : OID of function to be called + * result_buf : pointer to result buffer + * result_len : actual length of result is returned here + * result_is_int : If the result is an integer, this must be 1, + * otherwise this should be 0 + * args : pointer to an array of function arguments + * (each has length, if integer, and value/pointer) + * nargs : # of arguments in args array. + * + * RETURNS + * PGresult with status = PGRES_COMMAND_OK if successful. + * *result_len is > 0 if there is a return value, 0 if not. + * PGresult with status = PGRES_FATAL_ERROR if backend returns an error. + * NULL on communications failure. conn->errorMessage will be set. + * ---------------- + */ + +PGresult * +PQfn(PGconn *conn, + int fnid, + int *result_buf, + int *result_len, + int result_is_int, + const PQArgBlock *args, + int nargs) +{ + *result_len = 0; + + if (!conn) + return NULL; + + /* clear the error string */ + resetPQExpBuffer(&conn->errorMessage); + + if (conn->sock == PGINVALID_SOCKET || conn->asyncStatus != PGASYNC_IDLE || + conn->result != NULL) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("connection in wrong state\n")); + return NULL; + } + + if (PG_PROTOCOL_MAJOR(conn->pversion) >= 3) + return pqFunctionCall3(conn, fnid, + result_buf, result_len, + result_is_int, + args, nargs); + else + return pqFunctionCall2(conn, fnid, + result_buf, result_len, + result_is_int, + args, nargs); +} + + +/* ====== accessor funcs for PGresult ======== */ + +ExecStatusType +PQresultStatus(const PGresult *res) +{ + if (!res) + return PGRES_FATAL_ERROR; + return res->resultStatus; +} + +char * +PQresStatus(ExecStatusType status) +{ + if ((unsigned int) status >= sizeof pgresStatus / sizeof pgresStatus[0]) + return libpq_gettext("invalid ExecStatusType code"); + return pgresStatus[status]; +} + +char * +PQresultErrorMessage(const PGresult *res) +{ + if (!res || !res->errMsg) + return ""; + return res->errMsg; +} + +char * +PQresultVerboseErrorMessage(const PGresult *res, + PGVerbosity verbosity, + PGContextVisibility show_context) +{ + PQExpBufferData workBuf; + + /* + * Because the caller is expected to free the result string, we must + * strdup any constant result. We use plain strdup and document that + * callers should expect NULL if out-of-memory. + */ + if (!res || + (res->resultStatus != PGRES_FATAL_ERROR && + res->resultStatus != PGRES_NONFATAL_ERROR)) + return strdup(libpq_gettext("PGresult is not an error result\n")); + + initPQExpBuffer(&workBuf); + + /* + * Currently, we pass this off to fe-protocol3.c in all cases; it will + * behave reasonably sanely with an error reported by fe-protocol2.c as + * well. If necessary, we could record the protocol version in PGresults + * so as to be able to invoke a version-specific message formatter, but + * for now there's no need. + */ + pqBuildErrorMessage3(&workBuf, res, verbosity, show_context); + + /* If insufficient memory to format the message, fail cleanly */ + if (PQExpBufferDataBroken(workBuf)) + { + termPQExpBuffer(&workBuf); + return strdup(libpq_gettext("out of memory\n")); + } + + return workBuf.data; +} + +char * +PQresultErrorField(const PGresult *res, int fieldcode) +{ + PGMessageField *pfield; + + if (!res) + return NULL; + for (pfield = res->errFields; pfield != NULL; pfield = pfield->next) + { + if (pfield->code == fieldcode) + return pfield->contents; + } + return NULL; +} + +int +PQntuples(const PGresult *res) +{ + if (!res) + return 0; + return res->ntups; +} + +int +PQnfields(const PGresult *res) +{ + if (!res) + return 0; + return res->numAttributes; +} + +int +PQbinaryTuples(const PGresult *res) +{ + if (!res) + return 0; + return res->binary; +} + +/* + * Helper routines to range-check field numbers and tuple numbers. + * Return TRUE if OK, FALSE if not + */ + +static int +check_field_number(const PGresult *res, int field_num) +{ + if (!res) + return FALSE; /* no way to display error message... */ + if (field_num < 0 || field_num >= res->numAttributes) + { + pqInternalNotice(&res->noticeHooks, + "column number %d is out of range 0..%d", + field_num, res->numAttributes - 1); + return FALSE; + } + return TRUE; +} + +static int +check_tuple_field_number(const PGresult *res, + int tup_num, int field_num) +{ + if (!res) + return FALSE; /* no way to display error message... */ + if (tup_num < 0 || tup_num >= res->ntups) + { + pqInternalNotice(&res->noticeHooks, + "row number %d is out of range 0..%d", + tup_num, res->ntups - 1); + return FALSE; + } + if (field_num < 0 || field_num >= res->numAttributes) + { + pqInternalNotice(&res->noticeHooks, + "column number %d is out of range 0..%d", + field_num, res->numAttributes - 1); + return FALSE; + } + return TRUE; +} + +static int +check_param_number(const PGresult *res, int param_num) +{ + if (!res) + return FALSE; /* no way to display error message... */ + if (param_num < 0 || param_num >= res->numParameters) + { + pqInternalNotice(&res->noticeHooks, + "parameter number %d is out of range 0..%d", + param_num, res->numParameters - 1); + return FALSE; + } + + return TRUE; +} + +/* + * returns NULL if the field_num is invalid + */ +char * +PQfname(const PGresult *res, int field_num) +{ + if (!check_field_number(res, field_num)) + return NULL; + if (res->attDescs) + return res->attDescs[field_num].name; + else + return NULL; +} + +/* + * PQfnumber: find column number given column name + * + * The column name is parsed as if it were in a SQL statement, including + * case-folding and double-quote processing. But note a possible gotcha: + * downcasing in the frontend might follow different locale rules than + * downcasing in the backend... + * + * Returns -1 if no match. In the present backend it is also possible + * to have multiple matches, in which case the first one is found. + */ +int +PQfnumber(const PGresult *res, const char *field_name) +{ + char *field_case; + bool in_quotes; + bool all_lower = true; + const char *iptr; + char *optr; + int i; + + if (!res) + return -1; + + /* + * Note: it is correct to reject a zero-length input string; the proper + * input to match a zero-length field name would be "". + */ + if (field_name == NULL || + field_name[0] == '\0' || + res->attDescs == NULL) + return -1; + + /* + * Check if we can avoid the strdup() and related work because the + * passed-in string wouldn't be changed before we do the check anyway. + */ + for (iptr = field_name; *iptr; iptr++) + { + char c = *iptr; + + if (c == '"' || c != pg_tolower((unsigned char) c)) + { + all_lower = false; + break; + } + } + + if (all_lower) + for (i = 0; i < res->numAttributes; i++) + if (strcmp(field_name, res->attDescs[i].name) == 0) + return i; + + /* Fall through to the normal check if that didn't work out. */ + + /* + * Note: this code will not reject partially quoted strings, eg + * foo"BAR"foo will become fooBARfoo when it probably ought to be an error + * condition. + */ + field_case = strdup(field_name); + if (field_case == NULL) + return -1; /* grotty */ + + in_quotes = false; + optr = field_case; + for (iptr = field_case; *iptr; iptr++) + { + char c = *iptr; + + if (in_quotes) + { + if (c == '"') + { + if (iptr[1] == '"') + { + /* doubled quotes become a single quote */ + *optr++ = '"'; + iptr++; + } + else + in_quotes = false; + } + else + *optr++ = c; + } + else if (c == '"') + in_quotes = true; + else + { + c = pg_tolower((unsigned char) c); + *optr++ = c; + } + } + *optr = '\0'; + + for (i = 0; i < res->numAttributes; i++) + { + if (strcmp(field_case, res->attDescs[i].name) == 0) + { + free(field_case); + return i; + } + } + free(field_case); + return -1; +} + +Oid +PQftable(const PGresult *res, int field_num) +{ + if (!check_field_number(res, field_num)) + return InvalidOid; + if (res->attDescs) + return res->attDescs[field_num].tableid; + else + return InvalidOid; +} + +int +PQftablecol(const PGresult *res, int field_num) +{ + if (!check_field_number(res, field_num)) + return 0; + if (res->attDescs) + return res->attDescs[field_num].columnid; + else + return 0; +} + +int +PQfformat(const PGresult *res, int field_num) +{ + if (!check_field_number(res, field_num)) + return 0; + if (res->attDescs) + return res->attDescs[field_num].format; + else + return 0; +} + +Oid +PQftype(const PGresult *res, int field_num) +{ + if (!check_field_number(res, field_num)) + return InvalidOid; + if (res->attDescs) + return res->attDescs[field_num].typid; + else + return InvalidOid; +} + +int +PQfsize(const PGresult *res, int field_num) +{ + if (!check_field_number(res, field_num)) + return 0; + if (res->attDescs) + return res->attDescs[field_num].typlen; + else + return 0; +} + +int +PQfmod(const PGresult *res, int field_num) +{ + if (!check_field_number(res, field_num)) + return 0; + if (res->attDescs) + return res->attDescs[field_num].atttypmod; + else + return 0; +} + +char * +PQcmdStatus(PGresult *res) +{ + if (!res) + return NULL; + return res->cmdStatus; +} + +/* + * PQoidStatus - + * if the last command was an INSERT, return the oid string + * if not, return "" + */ +char * +PQoidStatus(const PGresult *res) +{ + /* + * This must be enough to hold the result. Don't laugh, this is better + * than what this function used to do. + */ + static char buf[24]; + + size_t len; + + if (!res || strncmp(res->cmdStatus, "INSERT ", 7) != 0) + return ""; + + len = strspn(res->cmdStatus + 7, "0123456789"); + if (len > sizeof(buf) - 1) + len = sizeof(buf) - 1; + memcpy(buf, res->cmdStatus + 7, len); + buf[len] = '\0'; + + return buf; +} + +/* + * PQoidValue - + * a perhaps preferable form of the above which just returns + * an Oid type + */ +Oid +PQoidValue(const PGresult *res) +{ + char *endptr = NULL; + unsigned long result; + + if (!res || + strncmp(res->cmdStatus, "INSERT ", 7) != 0 || + res->cmdStatus[7] < '0' || + res->cmdStatus[7] > '9') + return InvalidOid; + + result = strtoul(res->cmdStatus + 7, &endptr, 10); + + if (!endptr || (*endptr != ' ' && *endptr != '\0')) + return InvalidOid; + else + return (Oid) result; +} + + +/* + * PQcmdTuples - + * If the last command was INSERT/UPDATE/DELETE/MOVE/FETCH/COPY, return + * a string containing the number of inserted/affected tuples. If not, + * return "". + * + * XXX: this should probably return an int + */ +char * +PQcmdTuples(PGresult *res) +{ + char *p, + *c; + + if (!res) + return ""; + + if (strncmp(res->cmdStatus, "INSERT ", 7) == 0) + { + p = res->cmdStatus + 7; + /* INSERT: skip oid and space */ + while (*p && *p != ' ') + p++; + if (*p == 0) + goto interpret_error; /* no space? */ + p++; + } + else if (strncmp(res->cmdStatus, "SELECT ", 7) == 0 || + strncmp(res->cmdStatus, "DELETE ", 7) == 0 || + strncmp(res->cmdStatus, "UPDATE ", 7) == 0) + p = res->cmdStatus + 7; + else if (strncmp(res->cmdStatus, "FETCH ", 6) == 0) + p = res->cmdStatus + 6; + else if (strncmp(res->cmdStatus, "MOVE ", 5) == 0 || + strncmp(res->cmdStatus, "COPY ", 5) == 0) + p = res->cmdStatus + 5; + else + return ""; + + /* check that we have an integer (at least one digit, nothing else) */ + for (c = p; *c; c++) + { + if (!isdigit((unsigned char) *c)) + goto interpret_error; + } + if (c == p) + goto interpret_error; + + return p; + +interpret_error: + pqInternalNotice(&res->noticeHooks, + "could not interpret result from server: %s", + res->cmdStatus); + return ""; +} + +/* + * PQgetvalue: + * return the value of field 'field_num' of row 'tup_num' + */ +char * +PQgetvalue(const PGresult *res, int tup_num, int field_num) +{ + if (!check_tuple_field_number(res, tup_num, field_num)) + return NULL; + return res->tuples[tup_num][field_num].value; +} + +/* PQgetlength: + * returns the actual length of a field value in bytes. + */ +int +PQgetlength(const PGresult *res, int tup_num, int field_num) +{ + if (!check_tuple_field_number(res, tup_num, field_num)) + return 0; + if (res->tuples[tup_num][field_num].len != NULL_LEN) + return res->tuples[tup_num][field_num].len; + else + return 0; +} + +/* PQgetisnull: + * returns the null status of a field value. + */ +int +PQgetisnull(const PGresult *res, int tup_num, int field_num) +{ + if (!check_tuple_field_number(res, tup_num, field_num)) + return 1; /* pretend it is null */ + if (res->tuples[tup_num][field_num].len == NULL_LEN) + return 1; + else + return 0; +} + +/* PQnparams: + * returns the number of input parameters of a prepared statement. + */ +int +PQnparams(const PGresult *res) +{ + if (!res) + return 0; + return res->numParameters; +} + +/* PQparamtype: + * returns type Oid of the specified statement parameter. + */ +Oid +PQparamtype(const PGresult *res, int param_num) +{ + if (!check_param_number(res, param_num)) + return InvalidOid; + if (res->paramDescs) + return res->paramDescs[param_num].typid; + else + return InvalidOid; +} + + +/* PQsetnonblocking: + * sets the PGconn's database connection non-blocking if the arg is TRUE + * or makes it blocking if the arg is FALSE, this will not protect + * you from PQexec(), you'll only be safe when using the non-blocking API. + * Needs to be called only on a connected database connection. + */ +int +PQsetnonblocking(PGconn *conn, int arg) +{ + bool barg; + + if (!conn || conn->status == CONNECTION_BAD) + return -1; + + barg = (arg ? TRUE : FALSE); + + /* early out if the socket is already in the state requested */ + if (barg == conn->nonblocking) + return 0; + + /* + * to guarantee constancy for flushing/query/result-polling behavior we + * need to flush the send queue at this point in order to guarantee proper + * behavior. this is ok because either they are making a transition _from_ + * or _to_ blocking mode, either way we can block them. + */ + /* if we are going from blocking to non-blocking flush here */ + if (pqFlush(conn)) + return -1; + + conn->nonblocking = barg; + + return 0; +} + +/* + * return the blocking status of the database connection + * TRUE == nonblocking, FALSE == blocking + */ +int +PQisnonblocking(const PGconn *conn) +{ + return pqIsnonblocking(conn); +} + +/* libpq is thread-safe? */ +int +PQisthreadsafe(void) +{ +#ifdef ENABLE_THREAD_SAFETY + return true; +#else + return false; +#endif +} + + +/* try to force data out, really only useful for non-blocking users */ +int +PQflush(PGconn *conn) +{ + return pqFlush(conn); +} + + +/* + * PQfreemem - safely frees memory allocated + * + * Needed mostly by Win32, unless multithreaded DLL (/MD in VC6) + * Used for freeing memory from PQescapeByte()a/PQunescapeBytea() + */ +void +PQfreemem(void *ptr) +{ + free(ptr); +} + +/* + * PQfreeNotify - free's the memory associated with a PGnotify + * + * This function is here only for binary backward compatibility. + * New code should use PQfreemem(). A macro will automatically map + * calls to PQfreemem. It should be removed in the future. bjm 2003-03-24 + */ + +#undef PQfreeNotify +void PQfreeNotify(PGnotify *notify); + +void +PQfreeNotify(PGnotify *notify) +{ + PQfreemem(notify); +} + + +/* + * Escaping arbitrary strings to get valid SQL literal strings. + * + * Replaces "'" with "''", and if not std_strings, replaces "\" with "\\". + * + * length is the length of the source string. (Note: if a terminating NUL + * is encountered sooner, PQescapeString stops short of "length"; the behavior + * is thus rather like strncpy.) + * + * For safety the buffer at "to" must be at least 2*length + 1 bytes long. + * A terminating NUL character is added to the output string, whether the + * input is NUL-terminated or not. + * + * Returns the actual length of the output (not counting the terminating NUL). + */ +static size_t +PQescapeStringInternal(PGconn *conn, + char *to, const char *from, size_t length, + int *error, + int encoding, bool std_strings) +{ + const char *source = from; + char *target = to; + size_t remaining = length; + + if (error) + *error = 0; + + while (remaining > 0 && *source != '\0') + { + char c = *source; + int len; + int i; + + /* Fast path for plain ASCII */ + if (!IS_HIGHBIT_SET(c)) + { + /* Apply quoting if needed */ + if (SQL_STR_DOUBLE(c, !std_strings)) + *target++ = c; + /* Copy the character */ + *target++ = c; + source++; + remaining--; + continue; + } + + /* Slow path for possible multibyte characters */ + len = pg_encoding_mblen(encoding, source); + + /* Copy the character */ + for (i = 0; i < len; i++) + { + if (remaining == 0 || *source == '\0') + break; + *target++ = *source++; + remaining--; + } + + /* + * If we hit premature end of string (ie, incomplete multibyte + * character), try to pad out to the correct length with spaces. We + * may not be able to pad completely, but we will always be able to + * insert at least one pad space (since we'd not have quoted a + * multibyte character). This should be enough to make a string that + * the server will error out on. + */ + if (i < len) + { + if (error) + *error = 1; + if (conn) + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("incomplete multibyte character\n")); + for (; i < len; i++) + { + if (((size_t) (target - to)) / 2 >= length) + break; + *target++ = ' '; + } + break; + } + } + + /* Write the terminating NUL character. */ + *target = '\0'; + + return target - to; +} + +size_t +PQescapeStringConn(PGconn *conn, + char *to, const char *from, size_t length, + int *error) +{ + if (!conn) + { + /* force empty-string result */ + *to = '\0'; + if (error) + *error = 1; + return 0; + } + return PQescapeStringInternal(conn, to, from, length, error, + conn->client_encoding, + conn->std_strings); +} + +size_t +PQescapeString(char *to, const char *from, size_t length) +{ + return PQescapeStringInternal(NULL, to, from, length, NULL, + static_client_encoding, + static_std_strings); +} + + +/* + * Escape arbitrary strings. If as_ident is true, we escape the result + * as an identifier; if false, as a literal. The result is returned in + * a newly allocated buffer. If we fail due to an encoding violation or out + * of memory condition, we return NULL, storing an error message into conn. + */ +static char * +PQescapeInternal(PGconn *conn, const char *str, size_t len, bool as_ident) +{ + const char *s; + char *result; + char *rp; + int num_quotes = 0; /* single or double, depending on as_ident */ + int num_backslashes = 0; + int input_len; + int result_size; + char quote_char = as_ident ? '"' : '\''; + + /* We must have a connection, else fail immediately. */ + if (!conn) + return NULL; + + /* Scan the string for characters that must be escaped. */ + for (s = str; (s - str) < len && *s != '\0'; ++s) + { + if (*s == quote_char) + ++num_quotes; + else if (*s == '\\') + ++num_backslashes; + else if (IS_HIGHBIT_SET(*s)) + { + int charlen; + + /* Slow path for possible multibyte characters */ + charlen = pg_encoding_mblen(conn->client_encoding, s); + + /* Multibyte character overruns allowable length. */ + if ((s - str) + charlen > len || memchr(s, 0, charlen) != NULL) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("incomplete multibyte character\n")); + return NULL; + } + + /* Adjust s, bearing in mind that for loop will increment it. */ + s += charlen - 1; + } + } + + /* Allocate output buffer. */ + input_len = s - str; + result_size = input_len + num_quotes + 3; /* two quotes, plus a NUL */ + if (!as_ident && num_backslashes > 0) + result_size += num_backslashes + 2; + result = rp = (char *) malloc(result_size); + if (rp == NULL) + { + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("out of memory\n")); + return NULL; + } + + /* + * If we are escaping a literal that contains backslashes, we use the + * escape string syntax so that the result is correct under either value + * of standard_conforming_strings. We also emit a leading space in this + * case, to guard against the possibility that the result might be + * interpolated immediately following an identifier. + */ + if (!as_ident && num_backslashes > 0) + { + *rp++ = ' '; + *rp++ = 'E'; + } + + /* Opening quote. */ + *rp++ = quote_char; + + /* + * Use fast path if possible. + * + * We've already verified that the input string is well-formed in the + * current encoding. If it contains no quotes and, in the case of + * literal-escaping, no backslashes, then we can just copy it directly to + * the output buffer, adding the necessary quotes. + * + * If not, we must rescan the input and process each character + * individually. + */ + if (num_quotes == 0 && (num_backslashes == 0 || as_ident)) + { + memcpy(rp, str, input_len); + rp += input_len; + } + else + { + for (s = str; s - str < input_len; ++s) + { + if (*s == quote_char || (!as_ident && *s == '\\')) + { + *rp++ = *s; + *rp++ = *s; + } + else if (!IS_HIGHBIT_SET(*s)) + *rp++ = *s; + else + { + int i = pg_encoding_mblen(conn->client_encoding, s); + + while (1) + { + *rp++ = *s; + if (--i == 0) + break; + ++s; /* for loop will provide the final increment */ + } + } + } + } + + /* Closing quote and terminating NUL. */ + *rp++ = quote_char; + *rp = '\0'; + + return result; +} + +char * +PQescapeLiteral(PGconn *conn, const char *str, size_t len) +{ + return PQescapeInternal(conn, str, len, false); +} + +char * +PQescapeIdentifier(PGconn *conn, const char *str, size_t len) +{ + return PQescapeInternal(conn, str, len, true); +} + +/* HEX encoding support for bytea */ +static const char hextbl[] = "0123456789abcdef"; + +static const int8 hexlookup[128] = { + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1, + -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1, + -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, +}; + +static inline char +get_hex(char c) +{ + int res = -1; + + if (c > 0 && c < 127) + res = hexlookup[(unsigned char) c]; + + return (char) res; +} + + +/* + * PQescapeBytea - converts from binary string to the + * minimal encoding necessary to include the string in an SQL + * INSERT statement with a bytea type column as the target. + * + * We can use either hex or escape (traditional) encoding. + * In escape mode, the following transformations are applied: + * '\0' == ASCII 0 == \000 + * '\'' == ASCII 39 == '' + * '\\' == ASCII 92 == \\ + * anything < 0x20, or > 0x7e ---> \ooo + * (where ooo is an octal expression) + * + * If not std_strings, all backslashes sent to the output are doubled. + */ +static unsigned char * +PQescapeByteaInternal(PGconn *conn, + const unsigned char *from, size_t from_length, + size_t *to_length, bool std_strings, bool use_hex) +{ + const unsigned char *vp; + unsigned char *rp; + unsigned char *result; + size_t i; + size_t len; + size_t bslash_len = (std_strings ? 1 : 2); + + /* + * empty string has 1 char ('\0') + */ + len = 1; + + if (use_hex) + { + len += bslash_len + 1 + 2 * from_length; + } + else + { + vp = from; + for (i = from_length; i > 0; i--, vp++) + { + if (*vp < 0x20 || *vp > 0x7e) + len += bslash_len + 3; + else if (*vp == '\'') + len += 2; + else if (*vp == '\\') + len += bslash_len + bslash_len; + else + len++; + } + } + + *to_length = len; + rp = result = (unsigned char *) malloc(len); + if (rp == NULL) + { + if (conn) + printfPQExpBuffer(&conn->errorMessage, + libpq_gettext("out of memory\n")); + return NULL; + } + + if (use_hex) + { + if (!std_strings) + *rp++ = '\\'; + *rp++ = '\\'; + *rp++ = 'x'; + } + + vp = from; + for (i = from_length; i > 0; i--, vp++) + { + unsigned char c = *vp; + + if (use_hex) + { + *rp++ = hextbl[(c >> 4) & 0xF]; + *rp++ = hextbl[c & 0xF]; + } + else if (c < 0x20 || c > 0x7e) + { + if (!std_strings) + *rp++ = '\\'; + *rp++ = '\\'; + *rp++ = (c >> 6) + '0'; + *rp++ = ((c >> 3) & 07) + '0'; + *rp++ = (c & 07) + '0'; + } + else if (c == '\'') + { + *rp++ = '\''; + *rp++ = '\''; + } + else if (c == '\\') + { + if (!std_strings) + { + *rp++ = '\\'; + *rp++ = '\\'; + } + *rp++ = '\\'; + *rp++ = '\\'; + } + else + *rp++ = c; + } + *rp = '\0'; + + return result; +} + +unsigned char * +PQescapeByteaConn(PGconn *conn, + const unsigned char *from, size_t from_length, + size_t *to_length) +{ + if (!conn) + return NULL; + return PQescapeByteaInternal(conn, from, from_length, to_length, + conn->std_strings, + (conn->sversion >= 90000)); +} + +unsigned char * +PQescapeBytea(const unsigned char *from, size_t from_length, size_t *to_length) +{ + return PQescapeByteaInternal(NULL, from, from_length, to_length, + static_std_strings, + false /* can't use hex */ ); +} + + +#define ISFIRSTOCTDIGIT(CH) ((CH) >= '0' && (CH) <= '3') +#define ISOCTDIGIT(CH) ((CH) >= '0' && (CH) <= '7') +#define OCTVAL(CH) ((CH) - '0') + +/* + * PQunescapeBytea - converts the null terminated string representation + * of a bytea, strtext, into binary, filling a buffer. It returns a + * pointer to the buffer (or NULL on error), and the size of the + * buffer in retbuflen. The pointer may subsequently be used as an + * argument to the function PQfreemem. + * + * The following transformations are made: + * \\ == ASCII 92 == \ + * \ooo == a byte whose value = ooo (ooo is an octal number) + * \x == x (x is any character not matched by the above transformations) + */ +unsigned char * +PQunescapeBytea(const unsigned char *strtext, size_t *retbuflen) +{ + size_t strtextlen, + buflen; + unsigned char *buffer, + *tmpbuf; + size_t i, + j; + + if (strtext == NULL) + return NULL; + + strtextlen = strlen((const char *) strtext); + + if (strtext[0] == '\\' && strtext[1] == 'x') + { + const unsigned char *s; + unsigned char *p; + + buflen = (strtextlen - 2) / 2; + /* Avoid unportable malloc(0) */ + buffer = (unsigned char *) malloc(buflen > 0 ? buflen : 1); + if (buffer == NULL) + return NULL; + + s = strtext + 2; + p = buffer; + while (*s) + { + char v1, + v2; + + /* + * Bad input is silently ignored. Note that this includes + * whitespace between hex pairs, which is allowed by byteain. + */ + v1 = get_hex(*s++); + if (!*s || v1 == (char) -1) + continue; + v2 = get_hex(*s++); + if (v2 != (char) -1) + *p++ = (v1 << 4) | v2; + } + + buflen = p - buffer; + } + else + { + /* + * Length of input is max length of output, but add one to avoid + * unportable malloc(0) if input is zero-length. + */ + buffer = (unsigned char *) malloc(strtextlen + 1); + if (buffer == NULL) + return NULL; + + for (i = j = 0; i < strtextlen;) + { + switch (strtext[i]) + { + case '\\': + i++; + if (strtext[i] == '\\') + buffer[j++] = strtext[i++]; + else + { + if ((ISFIRSTOCTDIGIT(strtext[i])) && + (ISOCTDIGIT(strtext[i + 1])) && + (ISOCTDIGIT(strtext[i + 2]))) + { + int byte; + + byte = OCTVAL(strtext[i++]); + byte = (byte << 3) + OCTVAL(strtext[i++]); + byte = (byte << 3) + OCTVAL(strtext[i++]); + buffer[j++] = byte; + } + } + + /* + * Note: if we see '\' followed by something that isn't a + * recognized escape sequence, we loop around having done + * nothing except advance i. Therefore the something will + * be emitted as ordinary data on the next cycle. Corner + * case: '\' at end of string will just be discarded. + */ + break; + + default: + buffer[j++] = strtext[i++]; + break; + } + } + buflen = j; /* buflen is the length of the dequoted data */ + } + + /* Shrink the buffer to be no larger than necessary */ + /* +1 avoids unportable behavior when buflen==0 */ + tmpbuf = realloc(buffer, buflen + 1); + + /* It would only be a very brain-dead realloc that could fail, but... */ + if (!tmpbuf) + { + free(buffer); + return NULL; + } + + *retbuflen = buflen; + return tmpbuf; +} |