/*-------------------------------------------------------------------------
*
* fe-exec.c
* functions related to sending a query down to the backend
*
* Portions Copyright (c) 1996-2021, 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 <limits.h>
#ifdef WIN32
#include "win32.h"
#else
#include <unistd.h>
#endif
#include "libpq-fe.h"
#include "libpq-int.h"
#include "mb/pg_wchar.h"
/* 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",
"PGRES_PIPELINE_SYNC",
"PGRES_PIPELINE_ABORTED"
};
/*
* 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, size_t *memSize);
static bool pqAddTuple(PGresult *res, PGresAttValue *tup,
const char **errmsgp);
static int PQsendQueryInternal(PGconn *conn, const char *query, bool newQuery);
static bool PQsendQueryStart(PGconn *conn, bool newQuery);
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);
static void pqPipelineProcessQueue(PGconn *conn);
static int pqPipelineFlush(PGconn *conn);
/* ----------------
* 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;
result->memorySize = sizeof(PGresult);
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);
break;
}
/* copy events last; result must be valid if we need to PQclear */
if (conn->nEvents > 0)
{
result->events = dupEvents(conn->events, conn->nEvents,
&result->memorySize);
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,
&dest->memorySize);
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.
* The total space allocated is added to *memSize.
*/
static PGEvent *
dupEvents(PGEvent *events, int count, size_t *memSize)
{
PGEvent *newEvents;
size_t msize;
int i;
if (!events || count <= 0)
return NULL;
msize = count * sizeof(PGEvent);
newEvents = (PGEvent *) malloc(msize);
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;
}
msize += strlen(events[i].name) + 1;
}
*memSize += msize;
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.
* (On failure, we report the specific problem via pqInternalNotice.)
*/
int
PQsetvalue(PGresult *res, int tup_num, int field_num, char *value, int len)
{
PGresAttValue *attval;
const char *errmsg = NULL;
/* Note that this check also protects us against null "res" */
if (!check_field_number(res, field_num))
return false;
/* Invalid tup_num, must be <= ntups */
if (tup_num < 0 || tup_num > res->ntups)
{
pqInternalNotice(&res->noticeHooks,
"row number %d is out of range 0..%d",
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)
goto fail;
/* 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, &errmsg))
goto fail;
}
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)
goto fail;
attval->len = len;
memcpy(attval->value, value, len);
attval->value[len] = '\0';
}
return true;
/*
* Report failure via pqInternalNotice. If preceding code didn't provide
* an error message, assume "out of memory" was meant.
*/
fail:
if (!errmsg)
errmsg = libpq_gettext("out of memory");
pqInternalNotice(&res->noticeHooks, "%s", errmsg);
return false;
}
/*
* 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)
{
size_t alloc_size = nBytes + PGRESULT_BLOCK_OVERHEAD;
block = (PGresult_data *) malloc(alloc_size);
if (!block)
return NULL;
res->memorySize += alloc_size;
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;
res->memorySize += PGRESULT_DATA_BLOCKSIZE;
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;
}
/*
* PQresultMemorySize -
* Returns total space allocated for the PGresult.
*/
size_t
PQresultMemorySize(const PGresult *res)
{
if (!res)
return 0;
return res->memorySize;
}
/*
* 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, PQExpBuffer errorMessage)
{
char *msg;
if (!res)
return;
/*
* We handle two OOM scenarios here. The errorMessage buffer might be
* marked "broken" due to having previously failed to allocate enough
* memory for the message, or it might be fine but pqResultStrdup fails
* and returns NULL. In either case, just make res->errMsg point directly
* at a constant "out of memory" string.
*/
if (!PQExpBufferBroken(errorMessage))
msg = pqResultStrdup(res, errorMessage->data);
else
msg = NULL;
if (msg)
res->errMsg = msg;
else
res->errMsg = libpq_gettext("out of memory\n");
}
/*
* 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.
*/
void
pqSaveErrorResult(PGconn *conn)
{
pqClearAsyncResult(conn);
conn->result = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
}
/*
* As above, after appending conn->write_err_msg to whatever other error we
* have. This is used when we've detected a write failure and have exhausted
* our chances of reporting something else instead.
*/
static void
pqSaveWriteError(PGconn *conn)
{
/*
* If write_err_msg is null because of previous strdup failure, do what we
* can. (It's likely our machinations here will get OOM failures as well,
* but might as well try.)
*/
if (conn->write_err_msg)
{
appendPQExpBufferStr(&conn->errorMessage, conn->write_err_msg);
/* Avoid possibly appending the same message twice */
conn->write_err_msg[0] = '\0';
}
else
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("write to server failed\n"));
pqSaveErrorResult(conn);
}
/*
* 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.
*/
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);
/*
* 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, substitute "out of memory", as in pqSetResultError.
*/
res->errMsg = (char *) pqResultAlloc(res, strlen(msgBuf) + 2, false);
if (res->errMsg)
sprintf(res->errMsg, "%s\n", msgBuf);
else
res->errMsg = libpq_gettext("out of memory\n");
/*
* 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 an error prevented adding the row
*
* 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".
*/
static bool
pqAddTuple(PGresult *res, PGresAttValue *tup, const char **errmsgp)
{
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;
PGresAttValue **newTuples;
/*
* Since we use integers for row numbers, we can't support more than
* INT_MAX rows. Make sure we allow that many, though.
*/
if (res->tupArrSize <= INT_MAX / 2)
newSize = (res->tupArrSize > 0) ? res->tupArrSize * 2 : 128;
else if (res->tupArrSize < INT_MAX)
newSize = INT_MAX;
else
{
*errmsgp = libpq_gettext("PGresult cannot support more than INT_MAX tuples");
return false;
}
/*
* Also, on 32-bit platforms we could, in theory, overflow size_t even
* before newSize gets to INT_MAX. (In practice we'd doubtless hit
* OOM long before that, but let's check.)
*/
#if INT_MAX >= (SIZE_MAX / 2)
if (newSize > SIZE_MAX / sizeof(PGresAttValue *))
{
*errmsgp = libpq_gettext("size_t overflow");
return false;
}
#endif
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->memorySize +=
(newSize - res->tupArrSize) * sizeof(PGresAttValue *);
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;
/*
* 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;
}
/*
* Save values of settings that are of interest to libpq in fields of the
* PGconn object. We keep client_encoding and standard_conforming_strings
* 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)
{
/* We convert the server version to numeric form. */
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 */
}
else if (strcmp(name, "default_transaction_read_only") == 0)
{
conn->default_transaction_read_only =
(strcmp(value, "on") == 0) ? PG_BOOL_YES : PG_BOOL_NO;
}
else if (strcmp(name, "in_hot_standby") == 0)
{
conn->in_hot_standby =
(strcmp(value, "on") == 0) ? PG_BOOL_YES : PG_BOOL_NO;
}
}
/*
* 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, errmsgp))
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_MORE;
}
return 1;
fail:
/* release locally allocated PGresult, if we made one */
if (res != conn->result)
PQclear(res);
return 0;
}
/*
* pqAllocCmdQueueEntry
* Get a command queue entry for caller to fill.
*
* If the recycle queue has a free element, that is returned; if not, a
* fresh one is allocated. Caller is responsible for adding it to the
* command queue (pqAppendCmdQueueEntry) once the struct is filled in, or
* releasing the memory (pqRecycleCmdQueueEntry) if an error occurs.
*
* If allocation fails, sets the error message and returns NULL.
*/
static PGcmdQueueEntry *
pqAllocCmdQueueEntry(PGconn *conn)
{
PGcmdQueueEntry *entry;
if (conn->cmd_queue_recycle == NULL)
{
entry = (PGcmdQueueEntry *) malloc(sizeof(PGcmdQueueEntry));
if (entry == NULL)
{
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("out of memory\n"));
return NULL;
}
}
else
{
entry = conn->cmd_queue_recycle;
conn->cmd_queue_recycle = entry->next;
}
entry->next = NULL;
entry->query = NULL;
return entry;
}
/*
* pqAppendCmdQueueEntry
* Append a caller-allocated entry to the command queue, and update
* conn->asyncStatus to account for it.
*
* The query itself must already have been put in the output buffer by the
* caller.
*/
static void
pqAppendCmdQueueEntry(PGconn *conn, PGcmdQueueEntry *entry)
{
Assert(entry->next == NULL);
if (conn->cmd_queue_head == NULL)
conn->cmd_queue_head = entry;
else
conn->cmd_queue_tail->next = entry;
conn->cmd_queue_tail = entry;
switch (conn->pipelineStatus)
{
case PQ_PIPELINE_OFF:
case PQ_PIPELINE_ON:
/*
* When not in pipeline aborted state, if there's a result ready
* to be consumed, let it be so (that is, don't change away from
* READY or READY_MORE); otherwise set us busy to wait for
* something to arrive from the server.
*/
if (conn->asyncStatus == PGASYNC_IDLE)
conn->asyncStatus = PGASYNC_BUSY;
break;
case PQ_PIPELINE_ABORTED:
/*
* In aborted pipeline state, we don't expect anything from the
* server (since we don't send any queries that are queued).
* Therefore, if IDLE then do what PQgetResult would do to let
* itself consume commands from the queue; if we're in any other
* state, we don't have to do anything.
*/
if (conn->asyncStatus == PGASYNC_IDLE)
{
resetPQExpBuffer(&conn->errorMessage);
pqPipelineProcessQueue(conn);
}
break;
}
}
/*
* pqRecycleCmdQueueEntry
* Push a command queue entry onto the freelist.
*/
static void
pqRecycleCmdQueueEntry(PGconn *conn, PGcmdQueueEntry *entry)
{
if (entry == NULL)
return;
/* recyclable entries should not have a follow-on command */
Assert(entry->next == NULL);
if (entry->query)
{
free(entry->query);
entry->query = NULL;
}
entry->next = conn->cmd_queue_recycle;
conn->cmd_queue_recycle = entry;
}
/*
* PQsendQuery
* Submit a query, but don't wait for it to finish
*
* Returns: 1 if successfully submitted
* 0 if error (conn->errorMessage is set)
*
* PQsendQueryContinue is a non-exported version that behaves identically
* except that it doesn't reset conn->errorMessage.
*/
int
PQsendQuery(PGconn *conn, const char *query)
{
return PQsendQueryInternal(conn, query, true);
}
int
PQsendQueryContinue(PGconn *conn, const char *query)
{
return PQsendQueryInternal(conn, query, false);
}
static int
PQsendQueryInternal(PGconn *conn, const char *query, bool newQuery)
{
PGcmdQueueEntry *entry = NULL;
if (!PQsendQueryStart(conn, newQuery))
return 0;
/* check the argument */
if (!query)
{
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("command string is a null pointer\n"));
return 0;
}
entry = pqAllocCmdQueueEntry(conn);
if (entry == NULL)
return 0; /* error msg already set */
/* Send the query message(s) */
if (conn->pipelineStatus == PQ_PIPELINE_OFF)
{
/* construct the outgoing Query message */
if (pqPutMsgStart('Q', conn) < 0 ||
pqPuts(query, conn) < 0 ||
pqPutMsgEnd(conn) < 0)
{
/* error message should be set up already */
pqRecycleCmdQueueEntry(conn, entry);
return 0;
}
/* remember we are using simple query protocol */
entry->queryclass = PGQUERY_SIMPLE;
/* and remember the query text too, if possible */
entry->query = strdup(query);
}
else
{
/*
* In pipeline mode we cannot use the simple protocol, so we send
* Parse, Bind, Describe Portal, Execute, Close Portal (with the
* unnamed portal).
*/
if (pqPutMsgStart('P', conn) < 0 ||
pqPuts("", conn) < 0 ||
pqPuts(query, conn) < 0 ||
pqPutInt(0, 2, conn) < 0 ||
pqPutMsgEnd(conn) < 0)
goto sendFailed;
if (pqPutMsgStart('B', conn) < 0 ||
pqPuts("", conn) < 0 ||
pqPuts("", conn) < 0 ||
pqPutInt(0, 2, conn) < 0 ||
pqPutInt(0, 2, conn) < 0 ||
pqPutInt(0, 2, conn) < 0 ||
pqPutMsgEnd(conn) < 0)
goto sendFailed;
if (pqPutMsgStart('D', conn) < 0 ||
pqPutc('P', conn) < 0 ||
pqPuts("", conn) < 0 ||
pqPutMsgEnd(conn) < 0)
goto sendFailed;
if (pqPutMsgStart('E', conn) < 0 ||
pqPuts("", conn) < 0 ||
pqPutInt(0, 4, conn) < 0 ||
pqPutMsgEnd(conn) < 0)
goto sendFailed;
if (pqPutMsgStart('C', conn) < 0 ||
pqPutc('P', conn) < 0 ||
pqPuts("", conn) < 0 ||
pqPutMsgEnd(conn) < 0)
goto sendFailed;
entry->queryclass = PGQUERY_EXTENDED;
entry->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 (pqPipelineFlush(conn) < 0)
goto sendFailed;
/* OK, it's launched! */
pqAppendCmdQueueEntry(conn, entry);
return 1;
sendFailed:
pqRecycleCmdQueueEntry(conn, entry);
/* error message should be set up already */
return 0;
}
/*
* PQsendQueryParams
* Like PQsendQuery, but use extended query protocol 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, true))
return 0;
/* check the arguments */
if (!command)
{
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("command string is a null pointer\n"));
return 0;
}
if (nParams < 0 || nParams > PQ_QUERY_PARAM_MAX_LIMIT)
{
appendPQExpBuffer(&conn->errorMessage,
libpq_gettext("number of parameters must be between 0 and %d\n"),
PQ_QUERY_PARAM_MAX_LIMIT);
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)
{
PGcmdQueueEntry *entry = NULL;
if (!PQsendQueryStart(conn, true))
return 0;
/* check the arguments */
if (!stmtName)
{
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("statement name is a null pointer\n"));
return 0;
}
if (!query)
{
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("command string is a null pointer\n"));
return 0;
}
if (nParams < 0 || nParams > PQ_QUERY_PARAM_MAX_LIMIT)
{
appendPQExpBuffer(&conn->errorMessage,
libpq_gettext("number of parameters must be between 0 and %d\n"),
PQ_QUERY_PARAM_MAX_LIMIT);
return 0;
}
entry = pqAllocCmdQueueEntry(conn);
if (entry == NULL)
return 0; /* error msg already set */
/* construct the Parse message */
if (pqPutMsgStart('P', 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;
/* Add a Sync, unless in pipeline mode. */
if (conn->pipelineStatus == PQ_PIPELINE_OFF)
{
if (pqPutMsgStart('S', conn) < 0 ||
pqPutMsgEnd(conn) < 0)
goto sendFailed;
}
/* remember we are doing just a Parse */
entry->queryclass = PGQUERY_PREPARE;
/* and remember the query text too, if possible */
/* if insufficient memory, query just winds up NULL */
entry->query = strdup(query);
/*
* Give the data a push (in pipeline mode, only if we're past the size
* threshold). In nonblock mode, don't complain if we're unable to send
* it all; PQgetResult() will do any additional flushing needed.
*/
if (pqPipelineFlush(conn) < 0)
goto sendFailed;
/* OK, it's launched! */
pqAppendCmdQueueEntry(conn, entry);
return 1;
sendFailed:
pqRecycleCmdQueueEntry(conn, entry);
/* error message should be set up already */
return 0;
}
/*
* PQsendQueryPrepared
* Like PQsendQuery, but execute a previously prepared statement,
* using extended query protocol 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, true))
return 0;
/* check the arguments */
if (!stmtName)
{
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("statement name is a null pointer\n"));
return 0;
}
if (nParams < 0 || nParams > PQ_QUERY_PARAM_MAX_LIMIT)
{
appendPQExpBuffer(&conn->errorMessage,
libpq_gettext("number of parameters must be between 0 and %d\n"),
PQ_QUERY_PARAM_MAX_LIMIT);
return 0;
}
return PQsendQueryGuts(conn,
NULL, /* no command to parse */
stmtName,
nParams,
NULL, /* no param types */
paramValues,
paramLengths,
paramFormats,
resultFormat);
}
/*
* PQsendQueryStart
* Common startup code for PQsendQuery and sibling routines
*/
static bool
PQsendQueryStart(PGconn *conn, bool newQuery)
{
if (!conn)
return false;
/*
* If this is the beginning of a query cycle, reset the error buffer.
*/
if (newQuery)
resetPQExpBuffer(&conn->errorMessage);
/* Don't try to send if we know there's no live connection. */
if (conn->status != CONNECTION_OK)
{
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("no connection to the server\n"));
return false;
}
/* Can't send while already busy, either, unless enqueuing for later */
if (conn->asyncStatus != PGASYNC_IDLE &&
conn->pipelineStatus == PQ_PIPELINE_OFF)
{
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("another command is already in progress\n"));
return false;
}
if (conn->pipelineStatus != PQ_PIPELINE_OFF)
{
/*
* When enqueuing commands we don't change much of the connection
* state since it's already in use for the current command. The
* connection state will get updated when pqPipelineProcessQueue()
* advances to start processing the queued message.
*
* Just make sure we can safely enqueue given the current connection
* state. We can enqueue behind another queue item, or behind a
* non-queue command (one that sends its own sync), but we can't
* enqueue if the connection is in a copy state.
*/
switch (conn->asyncStatus)
{
case PGASYNC_IDLE:
case PGASYNC_READY:
case PGASYNC_READY_MORE:
case PGASYNC_BUSY:
/* ok to queue */
break;
case PGASYNC_COPY_IN:
case PGASYNC_COPY_OUT:
case PGASYNC_COPY_BOTH:
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("cannot queue commands during COPY\n"));
return false;
}
}
else
{
/*
* This command's results will come in immediately. 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 sending a query with extended query protocol
* 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;
PGcmdQueueEntry *entry;
entry = pqAllocCmdQueueEntry(conn);
if (entry == NULL)
return 0; /* error msg already set */
/*
* We will send Parse (if needed), Bind, Describe Portal, Execute, Sync
* (if not in pipeline mode), using specified statement name and the
* unnamed portal.
*/
if (command)
{
/* construct the Parse message */
if (pqPutMsgStart('P', 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', 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
{
appendPQExpBufferStr(&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', conn) < 0 ||
pqPutc('P', conn) < 0 ||
pqPuts("", conn) < 0 ||
pqPutMsgEnd(conn) < 0)
goto sendFailed;
/* construct the Execute message */
if (pqPutMsgStart('E', conn) < 0 ||
pqPuts("", conn) < 0 ||
pqPutInt(0, 4, conn) < 0 ||
pqPutMsgEnd(conn) < 0)
goto sendFailed;
/* construct the Sync message if not in pipeline mode */
if (conn->pipelineStatus == PQ_PIPELINE_OFF)
{
if (pqPutMsgStart('S', conn) < 0 ||
pqPutMsgEnd(conn) < 0)
goto sendFailed;
}
/* remember we are using extended query protocol */
entry->queryclass = PGQUERY_EXTENDED;
/* and remember the query text too, if possible */
/* if insufficient memory, query just winds up NULL */
if (command)
entry->query = strdup(command);
/*
* Give the data a push (in pipeline mode, only if we're past the size
* threshold). In nonblock mode, don't complain if we're unable to send
* it all; PQgetResult() will do any additional flushing needed.
*/
if (pqPipelineFlush(conn) < 0)
goto sendFailed;
/* OK, it's launched! */
pqAppendCmdQueueEntry(conn, entry);
return 1;
sendFailed:
pqRecycleCmdQueueEntry(conn, entry);
/* error message should be set up already */
return 0;
}
/*
* 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->cmd_queue_head ||
(conn->cmd_queue_head->queryclass != PGQUERY_SIMPLE &&
conn->cmd_queue_head->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)
{
pqParseInput3(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, or if we
* had a write failure.
*/
return conn->asyncStatus == PGASYNC_BUSY || conn->write_failed;
}
/*
* 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).
*
* In pipeline mode, once all the result of a query have been returned,
* PQgetResult returns NULL to let the user know that the next
* query is being processed. At the end of the pipeline, returns a
* result with PQresultStatus(result) == PGRES_PIPELINE_SYNC.
*/
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. (Note: if the connection has
* been lost, pqWait should return immediately because the socket
* should be read-ready, either with the last server data or with an
* EOF indication. We expect therefore that this won't result in any
* undue delay in reporting a previous write failure.)
*/
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);
/*
* If we had a write error, but nothing above obtained a query result
* or detected a read error, report the write error.
*/
if (conn->write_failed && conn->asyncStatus == PGASYNC_BUSY)
{
pqSaveWriteError(conn);
conn->asyncStatus = PGASYNC_IDLE;
return pqPrepareAsyncResult(conn);
}
}
/* Return the appropriate thing. */
switch (conn->asyncStatus)
{
case PGASYNC_IDLE:
res = NULL; /* query is complete */
if (conn->pipelineStatus != PQ_PIPELINE_OFF)
{
/*
* We're about to return the NULL that terminates the round of
* results from the current query; prepare to send the results
* of the next query when we're called next. Also, since this
* is the start of the results of the next query, clear any
* prior error message.
*/
resetPQExpBuffer(&conn->errorMessage);
pqPipelineProcessQueue(conn);
}
break;
case PGASYNC_READY:
/*
* For any query type other than simple query protocol, we advance
* the command queue here. This is because for simple query
* protocol we can get the READY state multiple times before the
* command is actually complete, since the command string can
* contain many queries. In simple query protocol, the queue
* advance is done by fe-protocol3 when it receives ReadyForQuery.
*/
if (conn->cmd_queue_head &&
conn->cmd_queue_head->queryclass != PGQUERY_SIMPLE)
pqCommandQueueAdvance(conn);
res = pqPrepareAsyncResult(conn);
if (conn->pipelineStatus != PQ_PIPELINE_OFF)
{
/*
* We're about to send the results of the current query. Set
* us idle now, and ...
*/
conn->asyncStatus = PGASYNC_IDLE;
/*
* ... in cases when we're sending a pipeline-sync result,
* move queue processing forwards immediately, so that next
* time we're called, we're prepared to return the next result
* received from the server. In all other cases, leave the
* queue state change for next time, so that a terminating
* NULL result is sent.
*
* (In other words: we don't return a NULL after a pipeline
* sync.)
*/
if (res && res->resultStatus == PGRES_PIPELINE_SYNC)
pqPipelineProcessQueue(conn);
}
else
{
/* Set the state back to BUSY, allowing parsing to proceed. */
conn->asyncStatus = PGASYNC_BUSY;
}
break;
case PGASYNC_READY_MORE:
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:
appendPQExpBuffer(&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))
{
appendPQExpBuffer(&conn->errorMessage,
libpq_gettext("PGEventProc \"%s\" failed during PGEVT_RESULTCREATE event\n"),
res->events[i].name);
pqSetResultError(res, &conn->errorMessage);
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 extended query protocol 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 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 extended query protocol 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;
if (conn->pipelineStatus != PQ_PIPELINE_OFF)
{
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("synchronous command execution functions are not allowed in pipeline mode\n"));
return false;
}
/*
* Since this is the beginning of a query cycle, reset the error buffer.
*/
resetPQExpBuffer(&conn->errorMessage);
/*
* 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)
{
/* 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 if (resultStatus == PGRES_COPY_OUT)
{
/*
* 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 if (resultStatus == PGRES_COPY_BOTH)
{
/* We don't allow PQexec during COPY BOTH */
appendPQExpBufferStr(&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. (We used to have logic here to concatenate successive error
* messages, but now that happens automatically, since conn->errorMessage
* will continue to accumulate errors throughout this loop.)
*
* 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)
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)
{
PGcmdQueueEntry *entry = NULL;
/* Treat null desc_target as empty string */
if (!desc_target)
desc_target = "";
if (!PQsendQueryStart(conn, true))
return 0;
entry = pqAllocCmdQueueEntry(conn);
if (entry == NULL)
return 0; /* error msg already set */
/* construct the Describe message */
if (pqPutMsgStart('D', conn) < 0 ||
pqPutc(desc_type, conn) < 0 ||
pqPuts(desc_target, conn) < 0 ||
pqPutMsgEnd(conn) < 0)
goto sendFailed;
/* construct the Sync message */
if (conn->pipelineStatus == PQ_PIPELINE_OFF)
{
if (pqPutMsgStart('S', conn) < 0 ||
pqPutMsgEnd(conn) < 0)
goto sendFailed;
}
/* remember we are doing a Describe */
entry->queryclass = PGQUERY_DESCRIBE;
/*
* Give the data a push (in pipeline mode, only if we're past the size
* threshold). In nonblock mode, don't complain if we're unable to send
* it all; PQgetResult() will do any additional flushing needed.
*/
if (pqPipelineFlush(conn) < 0)
goto sendFailed;
/* OK, it's launched! */
pqAppendCmdQueueEntry(conn, entry);
return 1;
sendFailed:
pqRecycleCmdQueueEntry(conn, entry);
/* error message should be set up already */
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
*
* Note that this function does not read any new data from the socket;
* so usually, caller should call PQconsumeInput() first.
*/
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)
{
appendPQExpBufferStr(&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.)
*/
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 (pqPutMsgStart('d', 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)
{
appendPQExpBufferStr(&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 (errormsg)
{
/* Send COPY FAIL */
if (pqPutMsgStart('f', conn) < 0 ||
pqPuts(errormsg, conn) < 0 ||
pqPutMsgEnd(conn) < 0)
return -1;
}
else
{
/* Send COPY DONE */
if (pqPutMsgStart('c', conn) < 0 ||
pqPutMsgEnd(conn) < 0)
return -1;
}
/*
* If we sent the COPY command in extended-query mode, we must issue a
* Sync as well.
*/
if (conn->cmd_queue_head &&
conn->cmd_queue_head->queryclass != PGQUERY_SIMPLE)
{
if (pqPutMsgStart('S', conn) < 0 ||
pqPutMsgEnd(conn) < 0)
return -1;
}
/* Return to active duty */
if (conn->asyncStatus == PGASYNC_COPY_BOTH)
conn->asyncStatus = PGASYNC_COPY_OUT;
else
conn->asyncStatus = PGASYNC_BUSY;
/* 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)
{
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("no COPY in progress\n"));
return -2;
}
return pqGetCopyData3(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;
return pqGetline3(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;
return pqGetlineAsync3(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.
*
* This is deprecated; it's cleaner to use PQgetResult to get the transfer
* status.
*
* RETURNS:
* 0 on success
* 1 on failure
*/
int
PQendcopy(PGconn *conn)
{
if (!conn)
return 0;
return pqEndcopy3(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;
/*
* Since this is the beginning of a query cycle, reset the error buffer.
*/
resetPQExpBuffer(&conn->errorMessage);
if (conn->pipelineStatus != PQ_PIPELINE_OFF)
{
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("PQfn not allowed in pipeline mode\n"));
return NULL;
}
if (conn->sock == PGINVALID_SOCKET || conn->asyncStatus != PGASYNC_IDLE ||
conn->result != NULL)
{
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("connection in wrong state\n"));
return NULL;
}
return pqFunctionCall3(conn, fnid,
result_buf, result_len,
result_is_int,
args, nargs);
}
/* ====== Pipeline mode support ======== */
/*
* PQenterPipelineMode
* Put an idle connection in pipeline mode.
*
* Returns 1 on success. On failure, errorMessage is set and 0 is returned.
*
* Commands submitted after this can be pipelined on the connection;
* there's no requirement to wait for one to finish before the next is
* dispatched.
*
* Queuing of a new query or syncing during COPY is not allowed.
*
* A set of commands is terminated by a PQpipelineSync. Multiple sync
* points can be established while in pipeline mode. Pipeline mode can
* be exited by calling PQexitPipelineMode() once all results are processed.
*
* This doesn't actually send anything on the wire, it just puts libpq
* into a state where it can pipeline work.
*/
int
PQenterPipelineMode(PGconn *conn)
{
if (!conn)
return 0;
/* succeed with no action if already in pipeline mode */
if (conn->pipelineStatus != PQ_PIPELINE_OFF)
return 1;
if (conn->asyncStatus != PGASYNC_IDLE)
{
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("cannot enter pipeline mode, connection not idle\n"));
return 0;
}
conn->pipelineStatus = PQ_PIPELINE_ON;
return 1;
}
/*
* PQexitPipelineMode
* End pipeline mode and return to normal command mode.
*
* Returns 1 in success (pipeline mode successfully ended, or not in pipeline
* mode).
*
* Returns 0 if in pipeline mode and cannot be ended yet. Error message will
* be set.
*/
int
PQexitPipelineMode(PGconn *conn)
{
if (!conn)
return 0;
if (conn->pipelineStatus == PQ_PIPELINE_OFF)
return 1;
switch (conn->asyncStatus)
{
case PGASYNC_READY:
case PGASYNC_READY_MORE:
/* there are some uncollected results */
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("cannot exit pipeline mode with uncollected results\n"));
return 0;
case PGASYNC_BUSY:
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("cannot exit pipeline mode while busy\n"));
return 0;
default:
/* OK */
break;
}
/* still work to process */
if (conn->cmd_queue_head != NULL)
{
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("cannot exit pipeline mode with uncollected results\n"));
return 0;
}
conn->pipelineStatus = PQ_PIPELINE_OFF;
conn->asyncStatus = PGASYNC_IDLE;
/* Flush any pending data in out buffer */
if (pqFlush(conn) < 0)
return 0; /* error message is setup already */
return 1;
}
/*
* pqCommandQueueAdvance
* Remove one query from the command queue, when we receive
* all results from the server that pertain to it.
*/
void
pqCommandQueueAdvance(PGconn *conn)
{
PGcmdQueueEntry *prevquery;
if (conn->cmd_queue_head == NULL)
return;
/* delink from queue */
prevquery = conn->cmd_queue_head;
conn->cmd_queue_head = conn->cmd_queue_head->next;
/* and make it recyclable */
prevquery->next = NULL;
pqRecycleCmdQueueEntry(conn, prevquery);
}
/*
* pqPipelineProcessQueue: subroutine for PQgetResult
* In pipeline mode, start processing the results of the next query in the queue.
*/
static void
pqPipelineProcessQueue(PGconn *conn)
{
switch (conn->asyncStatus)
{
case PGASYNC_COPY_IN:
case PGASYNC_COPY_OUT:
case PGASYNC_COPY_BOTH:
case PGASYNC_READY:
case PGASYNC_READY_MORE:
case PGASYNC_BUSY:
/* client still has to process current query or results */
return;
case PGASYNC_IDLE:
/* next query please */
break;
}
/* Nothing to do if not in pipeline mode, or queue is empty */
if (conn->pipelineStatus == PQ_PIPELINE_OFF ||
conn->cmd_queue_head == NULL)
return;
/* Initialize async result-accumulation state */
pqClearAsyncResult(conn);
/*
* Reset single-row processing mode. (Client has to set it up for each
* query, if desired.)
*/
conn->singleRowMode = false;
if (conn->pipelineStatus == PQ_PIPELINE_ABORTED &&
conn->cmd_queue_head->queryclass != PGQUERY_SYNC)
{
/*
* In an aborted pipeline we don't get anything from the server for
* each result; we're just discarding commands from the queue until we
* get to the next sync from the server.
*
* The PGRES_PIPELINE_ABORTED results tell the client that its queries
* got aborted.
*/
conn->result = PQmakeEmptyPGresult(conn, PGRES_PIPELINE_ABORTED);
if (!conn->result)
{
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("out of memory\n"));
pqSaveErrorResult(conn);
return;
}
conn->asyncStatus = PGASYNC_READY;
}
else
{
/* allow parsing to continue */
conn->asyncStatus = PGASYNC_BUSY;
}
}
/*
* PQpipelineSync
* Send a Sync message as part of a pipeline, and flush to server
*
* It's legal to start submitting more commands in the pipeline immediately,
* without waiting for the results of the current pipeline. There's no need to
* end pipeline mode and start it again.
*
* If a command in a pipeline fails, every subsequent command up to and including
* the result to the Sync message sent by PQpipelineSync gets set to
* PGRES_PIPELINE_ABORTED state. If the whole pipeline is processed without
* error, a PGresult with PGRES_PIPELINE_SYNC is produced.
*
* Queries can already have been sent before PQpipelineSync is called, but
* PQpipelineSync need to be called before retrieving command results.
*
* The connection will remain in pipeline mode and unavailable for new
* synchronous command execution functions until all results from the pipeline
* are processed by the client.
*/
int
PQpipelineSync(PGconn *conn)
{
PGcmdQueueEntry *entry;
if (!conn)
return 0;
if (conn->pipelineStatus == PQ_PIPELINE_OFF)
{
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("cannot send pipeline when not in pipeline mode\n"));
return 0;
}
switch (conn->asyncStatus)
{
case PGASYNC_COPY_IN:
case PGASYNC_COPY_OUT:
case PGASYNC_COPY_BOTH:
/* should be unreachable */
appendPQExpBufferStr(&conn->errorMessage,
"internal error: cannot send pipeline while in COPY\n");
return 0;
case PGASYNC_READY:
case PGASYNC_READY_MORE:
case PGASYNC_BUSY:
case PGASYNC_IDLE:
/* OK to send sync */
break;
}
entry = pqAllocCmdQueueEntry(conn);
if (entry == NULL)
return 0; /* error msg already set */
entry->queryclass = PGQUERY_SYNC;
entry->query = NULL;
/* construct the Sync message */
if (pqPutMsgStart('S', conn) < 0 ||
pqPutMsgEnd(conn) < 0)
goto sendFailed;
/*
* 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! */
pqAppendCmdQueueEntry(conn, entry);
return 1;
sendFailed:
pqRecycleCmdQueueEntry(conn, entry);
/* error message should be set up already */
return 0;
}
/*
* PQsendFlushRequest
* Send request for server to flush its buffer. Useful in pipeline
* mode when a sync point is not desired.
*/
int
PQsendFlushRequest(PGconn *conn)
{
if (!conn)
return 0;
/* Don't try to send if we know there's no live connection. */
if (conn->status != CONNECTION_OK)
{
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("no connection to the server\n"));
return 0;
}
/* Can't send while already busy, either, unless enqueuing for later */
if (conn->asyncStatus != PGASYNC_IDLE &&
conn->pipelineStatus == PQ_PIPELINE_OFF)
{
appendPQExpBufferStr(&conn->errorMessage,
libpq_gettext("another command is already in progress\n"));
return 0;
}
if (pqPutMsgStart('H', conn) < 0 ||
pqPutMsgEnd(conn) < 0)
{
return 0;
}
return 1;
}
/* ====== 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 >= lengthof(pgresStatus))
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);
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.
*
* Clear errorMessage in case pqFlush adds to it.
*/
resetPQExpBuffer(&conn->errorMessage);
/* 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);
}
/*
* pqPipelineFlush
*
* In pipeline mode, data will be flushed only when the out buffer reaches the
* threshold value. In non-pipeline mode, it behaves as stock pqFlush.
*
* Returns 0 on success.
*/
static int
pqPipelineFlush(PGconn *conn)
{
if ((conn->pipelineStatus != PQ_PIPELINE_ON) ||
(conn->outCount >= OUTBUFFER_THRESHOLD))
return pqFlush(conn);
return 0;
}
/*
* PQfreemem - safely frees memory allocated
*
* Needed mostly by Win32, unless multithreaded DLL (/MD in VC6)
* Used for freeing memory from PQescapeBytea()/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)
appendPQExpBufferStr(&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;
}
resetPQExpBuffer(&conn->errorMessage);
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;
resetPQExpBuffer(&conn->errorMessage);
/* 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)
{
appendPQExpBufferStr(&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)
{
appendPQExpBufferStr(&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)
appendPQExpBufferStr(&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;
resetPQExpBuffer(&conn->errorMessage);
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;
}