problems with large objects - Mailing list pgsql-interfaces
| From | Wolfgang Hottgenroth |
|---|---|
| Subject | problems with large objects |
| Date | |
| Msg-id | 37C6C901.B4EF504@ieee.org Whole thread Raw |
| List | pgsql-interfaces |
Hi.
I use the postgreSQL-database-system and esspecially I do some work with
the large-objects, which I use through the
Perl-library. Unfortunately since I switched from 6.4.2 to 6.5.1 my
tools
refused to work. lo_import didn't work anymore.
I traced it down through the libpq, where I found that a test with
lo_lseek in the lo_open-function (file: fe-lobj.c) fails. Going deeper
into the source and drawing a trace of debug-output across some files I
switched tracing from the libpq to the backend.
Here I found in be-fsstubs.c, that after the function lo_open sets a
cookie using the function newLOfd, just this cookie will be cleared by
lo_commit, which is called by CommitTransaction (in xact.c). The handle,
handed out to the application by the library-function lo_open is now not
longer valid and the next access through this handle fails.
I attach the test-application (in Perl, named db_test), the debug-output
of the application (and the outputs in the libpq) (db_test2.log), the
debug-output of postmaster
(post2.log) and the files I patched with my debug-output (you will find
them easily because in every line I changed there is the string 'WN').
Did anyone of you ever see this problem? Is there something wrong with
my
application (which works fine with 6.4.2)?
I hope someone of you find time to have a look on the files and also I
hope he or she can
help my. I want to use the postgreSQL on an Alpha, and 6.4.2 did not run
on the Alpha (o yes, when I remove all optimisation it does). (But don't
be confused: all the test I did runs on an
Intel-Machine.)
Thanks,
Wolfgang Hottgenroth
/*-------------------------------------------------------------------------
*
* be-fsstubs.c
* support for filesystem operations on large objects
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /usr/local/cvsroot/pgsql/src/backend/libpq/be-fsstubs.c,v 1.35 1999/06/04 21:13:38 tgl Exp $
*
* NOTES
* This should be moved to a more appropriate place. It is here
* for lack of a better place.
*
* Builtin functions for open/close/read/write operations on large objects.
*
* These functions operate in a private GlobalMemoryContext, which means
* that large object descriptors hang around until we destroy the context.
* That happens in lo_commit(). It'd be possible to prolong the lifetime
* of the context so that LO FDs are good across transactions (for example,
* we could release the context only if we see that no FDs remain open).
* But we'd need additional state in order to do the right thing at the
* end of an aborted transaction. FDs opened during an aborted xact would
* still need to be closed, since they might not be pointing at valid
* relations at all. For now, we'll stick with the existing documented
* semantics of LO FDs: they're only good within a transaction.
*
*-------------------------------------------------------------------------
*/
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>
#include <postgres.h>
#include <lib/dllist.h>
#include <libpq/libpq.h>
#include <libpq/libpq-fs.h>
#include <nodes/nodes.h>
#include <utils/memutils.h>
#include <lib/fstack.h>
#include <utils/mcxt.h>
#include <catalog/pg_shadow.h> /* for superuser() */
#include <storage/fd.h> /* for O_ */
#include <storage/large_object.h>
#include <libpq/be-fsstubs.h>
/* [PA] is Pascal André <andre@via.ecp.fr> */
/*#define FSDB 1*/
#define MAX_LOBJ_FDS 256
#define BUFSIZE 1024
#define FNAME_BUFSIZE 8192
static LargeObjectDesc *cookies[MAX_LOBJ_FDS];
static GlobalMemory fscxt = NULL;
static int newLOfd(LargeObjectDesc *lobjCookie);
static void deleteLOfd(int fd);
/*****************************************************************************
* File Interfaces for Large Objects
*****************************************************************************/
int
lo_open(Oid lobjId, int mode)
{
LargeObjectDesc *lobjDesc;
int fd;
MemoryContext currentContext;
#if 1 //FSDB
elog(NOTICE, "LOopen(%u,%d)", lobjId, mode);
#endif
if (fscxt == NULL)
fscxt = CreateGlobalMemory("Filesystem");
currentContext = MemoryContextSwitchTo((MemoryContext) fscxt);
lobjDesc = inv_open(lobjId, mode);
elog(NOTICE, "WN: be-fsstubs: lo_open: lobjDesc: %x", lobjDesc);
if (lobjDesc == NULL)
{ /* lookup failed */
MemoryContextSwitchTo(currentContext);
#if 1 //FSDB
elog(NOTICE, "cannot open large object %u", lobjId);
#endif
return -1;
}
fd = newLOfd(lobjDesc);
elog(NOTICE, "WN: be-fsstubs: lo_open: fd: %x", fd);
/* switch context back to orig. */
MemoryContextSwitchTo(currentContext);
#if 1 //FSDB
if (fd < 0) /* newLOfd couldn't find a slot */
elog(NOTICE, "Out of space for large object FDs");
#endif
elog(NOTICE, "WN: be-fsstubs: lo_open: return: %x", fd);
return fd;
}
int
lo_close(int fd)
{
MemoryContext currentContext;
if (fd < 0 || fd >= MAX_LOBJ_FDS)
{
elog(ERROR, "lo_close: large obj descriptor (%d) out of range", fd);
return -2;
}
if (cookies[fd] == NULL)
{
elog(ERROR, "lo_close: invalid large obj descriptor (%d)", fd);
return -3;
}
#if 1 //FSDB
elog(NOTICE, "LOclose(%d)", fd);
#endif
Assert(fscxt != NULL);
currentContext = MemoryContextSwitchTo((MemoryContext) fscxt);
inv_close(cookies[fd]);
MemoryContextSwitchTo(currentContext);
deleteLOfd(fd);
return 0;
}
/*
* We assume the large object supports byte oriented reads and seeks so
* that our work is easier.
*/
int
lo_read(int fd, char *buf, int len)
{
MemoryContext currentContext;
int status;
if (fd < 0 || fd >= MAX_LOBJ_FDS)
{
elog(ERROR, "lo_read: large obj descriptor (%d) out of range", fd);
return -2;
}
if (cookies[fd] == NULL)
{
elog(ERROR, "lo_read: invalid large obj descriptor (%d)", fd);
return -3;
}
Assert(fscxt != NULL);
currentContext = MemoryContextSwitchTo((MemoryContext) fscxt);
status = inv_read(cookies[fd], buf, len);
MemoryContextSwitchTo(currentContext);
return (status);
}
int
lo_write(int fd, char *buf, int len)
{
MemoryContext currentContext;
int status;
if (fd < 0 || fd >= MAX_LOBJ_FDS)
{
elog(ERROR, "lo_write: large obj descriptor (%d) out of range", fd);
return -2;
}
if (cookies[fd] == NULL)
{
elog(ERROR, "lo_write: invalid large obj descriptor (%d)", fd);
return -3;
}
Assert(fscxt != NULL);
currentContext = MemoryContextSwitchTo((MemoryContext) fscxt);
status = inv_write(cookies[fd], buf, len);
MemoryContextSwitchTo(currentContext);
return (status);
}
int
lo_lseek(int fd, int offset, int whence)
{
MemoryContext currentContext;
int status;
elog(NOTICE, "WN: be-fsstubs: lo_lseek, fd: %d", fd);
if (fd < 0 || fd >= MAX_LOBJ_FDS)
{
elog(ERROR, "lo_lseek: large obj descriptor (%d) out of range", fd);
return -2;
}
if (cookies[fd] == NULL)
{
elog(NOTICE, "WN: be-fsstubs: lo_lseek: cookies[%u]=%x", fd, cookies[fd]);
elog(ERROR, "lo_lseek: invalid large obj descriptor (%d)", fd);
return -3;
}
Assert(fscxt != NULL);
currentContext = MemoryContextSwitchTo((MemoryContext) fscxt);
status = inv_seek(cookies[fd], offset, whence);
MemoryContextSwitchTo(currentContext);
return status;
}
Oid
lo_creat(int mode)
{
LargeObjectDesc *lobjDesc;
MemoryContext currentContext;
Oid lobjId;
if (fscxt == NULL)
fscxt = CreateGlobalMemory("Filesystem");
currentContext = MemoryContextSwitchTo((MemoryContext) fscxt);
lobjDesc = inv_create(mode);
if (lobjDesc == NULL)
{
MemoryContextSwitchTo(currentContext);
return InvalidOid;
}
lobjId = RelationGetRelid(lobjDesc->heap_r);
inv_close(lobjDesc);
/* switch context back to original memory context */
MemoryContextSwitchTo(currentContext);
return lobjId;
}
int
lo_tell(int fd)
{
if (fd < 0 || fd >= MAX_LOBJ_FDS)
{
elog(ERROR, "lo_tell: large object descriptor (%d) out of range", fd);
return -2;
}
if (cookies[fd] == NULL)
{
elog(ERROR, "lo_tell: invalid large object descriptor (%d)", fd);
return -3;
}
/*
* We assume we do not need to switch contexts for inv_tell.
* That is true for now, but is probably more than this module
* ought to assume...
*/
return inv_tell(cookies[fd]);
}
int
lo_unlink(Oid lobjId)
{
/*
* inv_destroy does not need a context switch, indeed it doesn't
* touch any LO-specific data structures at all. (Again, that's
* probably more than this module ought to be assuming.)
*
* XXX there ought to be some code to clean up any open LOs that
* reference the specified relation... as is, they remain "open".
*/
return inv_destroy(lobjId);
}
/*****************************************************************************
* Read/Write using varlena
*****************************************************************************/
struct varlena *
loread(int fd, int len)
{
struct varlena *retval;
int totalread = 0;
retval = (struct varlena *) palloc(VARHDRSZ + len);
totalread = lo_read(fd, VARDATA(retval), len);
VARSIZE(retval) = totalread + VARHDRSZ;
return retval;
}
int
lowrite(int fd, struct varlena * wbuf)
{
int totalwritten;
int bytestowrite;
bytestowrite = VARSIZE(wbuf) - VARHDRSZ;
totalwritten = lo_write(fd, VARDATA(wbuf), bytestowrite);
return totalwritten;
}
/*****************************************************************************
* Import/Export of Large Object
*****************************************************************************/
/*
* lo_import -
* imports a file as an (inversion) large object.
*/
Oid
lo_import(text *filename)
{
File fd;
int nbytes,
tmp;
char buf[BUFSIZE];
char fnamebuf[FNAME_BUFSIZE];
LargeObjectDesc *lobj;
Oid lobjOid;
#ifndef ALLOW_DANGEROUS_LO_FUNCTIONS
if (!superuser())
elog(ERROR, "You must have Postgres superuser privilege to use "
"server-side lo_import().\n\tAnyone can use the "
"client-side lo_import() provided by libpq.");
#endif
/*
* open the file to be read in
*/
nbytes = VARSIZE(filename) - VARHDRSZ + 1;
if (nbytes > FNAME_BUFSIZE)
nbytes = FNAME_BUFSIZE;
StrNCpy(fnamebuf, VARDATA(filename), nbytes);
#ifndef __CYGWIN32__
fd = PathNameOpenFile(fnamebuf, O_RDONLY, 0666);
#else
fd = PathNameOpenFile(fnamebuf, O_RDONLY | O_BINARY, 0666);
#endif
if (fd < 0)
{ /* error */
elog(ERROR, "lo_import: can't open unix file \"%s\": %m",
fnamebuf);
}
/*
* create an inversion "object"
*/
lobj = inv_create(INV_READ | INV_WRITE);
if (lobj == NULL)
{
elog(ERROR, "lo_import: can't create inv object for \"%s\"",
fnamebuf);
}
/*
* the oid for the large object is just the oid of the relation
* XInv??? which contains the data.
*/
lobjOid = RelationGetRelid(lobj->heap_r);
/*
* read in from the Unix file and write to the inversion file
*/
while ((nbytes = FileRead(fd, buf, BUFSIZE)) > 0)
{
tmp = inv_write(lobj, buf, nbytes);
if (tmp < nbytes)
elog(ERROR, "lo_import: error while reading \"%s\"",
fnamebuf);
}
FileClose(fd);
inv_close(lobj);
return lobjOid;
}
/*
* lo_export -
* exports an (inversion) large object.
*/
int4
lo_export(Oid lobjId, text *filename)
{
File fd;
int nbytes,
tmp;
char buf[BUFSIZE];
char fnamebuf[FNAME_BUFSIZE];
LargeObjectDesc *lobj;
mode_t oumask;
#ifndef ALLOW_DANGEROUS_LO_FUNCTIONS
if (!superuser())
elog(ERROR, "You must have Postgres superuser privilege to use "
"server-side lo_export().\n\tAnyone can use the "
"client-side lo_export() provided by libpq.");
#endif
/*
* open the inversion "object"
*/
lobj = inv_open(lobjId, INV_READ);
if (lobj == NULL)
elog(ERROR, "lo_export: can't open inv object %u", lobjId);
/*
* open the file to be written to
*
* Note: we reduce backend's normal 077 umask to the slightly
* friendlier 022. This code used to drop it all the way to 0,
* but creating world-writable export files doesn't seem wise.
*/
nbytes = VARSIZE(filename) - VARHDRSZ + 1;
if (nbytes > FNAME_BUFSIZE)
nbytes = FNAME_BUFSIZE;
StrNCpy(fnamebuf, VARDATA(filename), nbytes);
oumask = umask((mode_t) 0022);
#ifndef __CYGWIN32__
fd = PathNameOpenFile(fnamebuf, O_CREAT | O_WRONLY | O_TRUNC, 0666);
#else
fd = PathNameOpenFile(fnamebuf, O_CREAT | O_WRONLY | O_TRUNC | O_BINARY, 0666);
#endif
umask(oumask);
if (fd < 0)
{ /* error */
elog(ERROR, "lo_export: can't open unix file \"%s\": %m",
fnamebuf);
}
/*
* read in from the Unix file and write to the inversion file
*/
while ((nbytes = inv_read(lobj, buf, BUFSIZE)) > 0)
{
tmp = FileWrite(fd, buf, nbytes);
if (tmp < nbytes)
elog(ERROR, "lo_export: error while writing \"%s\"",
fnamebuf);
}
inv_close(lobj);
FileClose(fd);
return 1;
}
/*
* lo_commit -
* prepares large objects for transaction commit [PA, 7/17/98]
*/
void
lo_commit(bool isCommit)
{
int i;
MemoryContext currentContext;
elog(NOTICE, "WN: be-fsstubs: lo_commit, isCommit: %u", isCommit);
if (fscxt == NULL)
return; /* no LO operations in this xact */
currentContext = MemoryContextSwitchTo((MemoryContext) fscxt);
/* Clean out still-open index scans (not necessary if aborting)
* and clear cookies array so that LO fds are no longer good.
*/
for (i = 0; i < MAX_LOBJ_FDS; i++)
{
if (cookies[i] != NULL)
{
if (isCommit)
inv_cleanindex(cookies[i]);
elog(NOTICE, "WN: be-fsstubs: cookies[%u]=NULL!", i);
cookies[i] = NULL;
}
}
MemoryContextSwitchTo(currentContext);
/* Release the LO memory context to prevent permanent memory leaks. */
GlobalMemoryDestroy(fscxt);
fscxt = NULL;
}
/*****************************************************************************
* Support routines for this file
*****************************************************************************/
static int
newLOfd(LargeObjectDesc *lobjCookie)
{
int i;
elog(NOTICE, "WN: be-fsstubs: newLOfd: MAX_LOBJ_FDS: %d, lobjCookie: %x", MAX_LOBJ_FDS, lobjCookie);
for (i = 0; i < MAX_LOBJ_FDS; i++)
{
elog(NOTICE, "WN: be-fsstubs: newLOfd: i: %d, cookies: %x", i, cookies[i]);
if (cookies[i] == NULL)
{
elog(NOTICE, "WN: be-fsstubs: newLOfd: cookie found!");
cookies[i] = lobjCookie;
elog(NOTICE, "WN: be-fsstubs: newLOfd: cookies[%u]=%x",i,cookies[i]);
return i;
}
}
return -1;
}
static void
deleteLOfd(int fd)
{
cookies[fd] = NULL;
}
#!/usr/bin/perl -w
use Pg;
my $conn;
#DB_Open(\$conn, "dbname=adrema");
#$conn = Pg::connectdb("dbname=adrema");
$conn = PQsetdb('','','','','adrema');
my $filename = 'test.dat';
my $oid;
#$oid = $conn->lo_import($filename);
#$oid = PQlo_import($conn, $filename);
$oid = PQlo_creat($conn, PGRES_INV_WRITE);
print "db_test: lo_creat: oid: $oid\n";
#print $conn->errorMessage;
my $fd;
$fd = PQlo_open($conn, $oid, PGRES_INV_WRITE);
print "db_test: lo_open: fd: $fd\n";
#print $conn->errorMessage;
PQfinish($conn);
NOTICE: WN: xact: StartTransaction
NOTICE: WN: be-fsstubs: lo_commit, isCommit: 1
NOTICE: WN: xact: StartTransaction
NOTICE: WN: be-fsstubs: lo_commit, isCommit: 1
NOTICE: WN: xact: StartTransaction
NOTICE: LOopen(19425,131072)
NOTICE: WN: be-fsstubs: lo_open: lobjDesc: 821fcd0
NOTICE: WN: be-fsstubs: newLOfd: MAX_LOBJ_FDS: 256, lobjCookie: 821fcd0
NOTICE: WN: be-fsstubs: newLOfd: i: 0, cookies: 0
NOTICE: WN: be-fsstubs: newLOfd: cookie found!
NOTICE: WN: be-fsstubs: newLOfd: cookies[0]=821fcd0
NOTICE: WN: be-fsstubs: lo_open: fd: 0
NOTICE: WN: be-fsstubs: lo_open: return: 0
NOTICE: WN: be-fsstubs: lo_commit, isCommit: 1
NOTICE: WN: be-fsstubs: cookies[0]=NULL!
NOTICE: WN: xact: StartTransaction
NOTICE: WN: be-fsstubs: lo_lseek, fd: 0
NOTICE: WN: be-fsstubs: lo_lseek: cookies[0]=0
NOTICE: WN: be-fsstubs: lo_commit, isCommit: 0
fe-exec, PQfn, A
fe-exec, PQfn, C: i:0
fe-exec, PQfn, E
fe-exec, PQfn, I
fe-exec, PQfn, J1:
fe-exec, PQfn, I
fe-exec, PQfn, J
fe-exec, PQfn, ID: N
fe-exec, PQfn, I
fe-exec, PQfn, J1: N
fe-exec, PQfn, I
fe-exec, PQfn, J
fe-exec, PQfn, ID: V
fe-exec, PQfn, 0
fe-exec, PQfn, 1
fe-exec, PQfn, 2
fe-exec, PQfn, 3: 4
fe-exec, PQfn, 3b: result_buf: 19425
fe-exec, PQfn, 5
fe-exec, PQfn, I
fe-exec, PQfn, ID: N
fe-exec, PQfn, I
fe-exec, PQfn, J1: N
fe-exec, PQfn, I
fe-exec, PQfn, J
fe-exec, PQfn, ID: Z
db_test: lo_creat: oid: 19425
fe-lobj, lo_open: 0
fe-lobj, lo_open: 1a
fe-exec, PQfn, A
fe-exec, PQfn, C: i:0
fe-exec, PQfn, E
fe-exec, PQfn, C: i:1
fe-exec, PQfn, E
fe-exec, PQfn, I
fe-exec, PQfn, J1: @
fe-exec, PQfn, I
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fe-exec, PQfn, J1: N
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fe-exec, PQfn, ID: N
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fe-exec, PQfn, J1: N
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fe-exec, PQfn, J
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fe-exec, PQfn, J1: N
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fe-exec, PQfn, J1: N
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fe-exec, PQfn, ID: V
fe-exec, PQfn, 0
fe-exec, PQfn, 1
fe-exec, PQfn, 2
fe-exec, PQfn, 3: 4
fe-exec, PQfn, 3b: result_buf: 0
fe-exec, PQfn, 5
fe-exec, PQfn, I
fe-exec, PQfn, ID: N
fe-exec, PQfn, I
fe-exec, PQfn, J1: N
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fe-exec, PQfn, ID: N
fe-exec, PQfn, I
fe-exec, PQfn, J1: N
fe-exec, PQfn, I
fe-exec, PQfn, J
fe-exec, PQfn, ID: Z
fe-lobj, lo_open: 2 (3b8,0)
fe-lobj, lo_open: 3
fe-exec, PQfn, A
fe-exec, PQfn, C: i:0
fe-exec, PQfn, E
fe-exec, PQfn, C: i:1
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fe-exec, PQfn, I
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fe-exec, PQfn, ID: N
fe-exec, PQfn, I
fe-exec, PQfn, J1: N
fe-exec, PQfn, I
fe-exec, PQfn, J
fe-exec, PQfn, ID: Z
fe-lobj, lo_open: 3a (0,ffffffff)
db_test: lo_open: fd: -1
/*-------------------------------------------------------------------------
*
* fe-exec.c
* functions related to sending a query down to the backend
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /usr/local/cvsroot/pgsql/src/interfaces/libpq/fe-exec.c,v 1.81 1999/05/28 01:54:53 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "libpq-fe.h"
#include "libpq-int.h"
#include "postgres.h"
#ifdef WIN32
#include "win32.h"
#else
#if !defined(NO_UNISTD_H)
#include <unistd.h>
#endif
#endif
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <ctype.h>
/* keep this in same order as ExecStatusType in libpq-fe.h */
const 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"
};
#define DONOTICE(conn,message) \
((*(conn)->noticeHook) ((conn)->noticeArg, (message)))
static int addTuple(PGresult *res, PGresAttValue *tup);
static void parseInput(PGconn *conn);
static void handleSendFailure(PGconn *conn);
static int getRowDescriptions(PGconn *conn);
static int getAnotherTuple(PGconn *conn, int binary);
static int getNotify(PGconn *conn);
static int getNotice(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.
* ----------------
*/
#ifdef MAX
#undef MAX
#endif
#define MAX(a,b) ((a) > (b) ? (a) : (b))
#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.
*
* Note this is exported --- you wouldn't think an application would need
* to build its own PGresults, but this has proven useful in both libpgtcl
* and the Perl5 interface, so maybe it's not so unreasonable.
*/
PGresult *
PQmakeEmptyPGresult(PGconn *conn, ExecStatusType status)
{
PGresult *result;
result = (PGresult *) malloc(sizeof(PGresult));
result->conn = conn; /* might be NULL */
result->ntups = 0;
result->numAttributes = 0;
result->attDescs = NULL;
result->tuples = NULL;
result->tupArrSize = 0;
result->resultStatus = status;
result->cmdStatus[0] = '\0';
result->binary = 0;
result->errMsg = NULL;
result->null_field[0] = '\0';
result->curBlock = NULL;
result->curOffset = 0;
result->spaceLeft = 0;
if (conn) /* 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:
/* non-error cases */
break;
default:
pqSetResultError(result, conn->errorMessage);
break;
}
}
return result;
}
/*
* 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, int nBytes, int 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 <= res->spaceLeft)
{
space = res->curBlock->space + res->curOffset;
res->curOffset += nBytes;
res->spaceLeft -= nBytes;
return space;
}
/*
* If the requested object is very large, give it its own block; this
* avoids wasting what might be most of the current block to start a
* new block. (We'd have to special-case requests bigger than the
* block size anyway.) The object is always given binary alignment in
* this case.
*/
if (nBytes >= PGRESULT_SEP_ALLOC_THRESHOLD)
{
block = (PGresult_data *) malloc(nBytes + PGRESULT_BLOCK_OVERHEAD);
if (!block)
return NULL;
space = block->space + PGRESULT_BLOCK_OVERHEAD;
if (res->curBlock)
{
/*
* Tuck special block below the active block, so that we don't
* have to waste the free space in the active block.
*/
block->next = res->curBlock->next;
res->curBlock->next = block;
}
else
{
/* Must set up the new block as the first active block. */
block->next = NULL;
res->curBlock = block;
res->spaceLeft = 0; /* be sure it's marked full */
}
return space;
}
/* Otherwise, start a new block. */
block = (PGresult_data *) malloc(PGRESULT_DATA_BLOCKSIZE);
if (!block)
return NULL;
block->next = res->curBlock;
res->curBlock = block;
if (isBinary)
{
/* object needs full alignment */
res->curOffset = PGRESULT_BLOCK_OVERHEAD;
res->spaceLeft = PGRESULT_DATA_BLOCKSIZE - PGRESULT_BLOCK_OVERHEAD;
}
else
{
/* we can cram it right after the overhead pointer */
res->curOffset = sizeof(PGresult_data);
res->spaceLeft = PGRESULT_DATA_BLOCKSIZE - sizeof(PGresult_data);
}
space = block->space + res->curOffset;
res->curOffset += nBytes;
res->spaceLeft -= nBytes;
return space;
}
/*
* pqResultStrdup -
* Like strdup, but the space is subsidiary PGresult space.
*/
char *
pqResultStrdup(PGresult *res, const char *str)
{
char *space = (char *) pqResultAlloc(res, strlen(str) + 1, FALSE);
if (space)
strcpy(space, str);
return space;
}
/*
* pqSetResultError -
* assign a new error message to a PGresult
*/
void
pqSetResultError(PGresult *res, const char *msg)
{
if (!res)
return;
if (msg && *msg)
res->errMsg = pqResultStrdup(res, msg);
else
res->errMsg = NULL;
}
/*
* PQclear -
* free's the memory associated with a PGresult
*/
void
PQclear(PGresult *res)
{
PGresult_data *block;
if (!res)
return;
/* 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);
/* Free the PGresult structure itself */
free(res);
}
/*
* Handy subroutine to deallocate any partially constructed async result.
*/
void
pqClearAsyncResult(PGconn *conn)
{
if (conn->result)
PQclear(conn->result);
conn->result = NULL;
conn->curTuple = NULL;
}
/*
* addTuple
* add a row pointer to the PGresult structure, growing it if necessary
* Returns TRUE if OK, FALSE if not enough memory to add the row
*/
static int
addTuple(PGresult *res, PGresAttValue *tup)
{
if (res->ntups >= res->tupArrSize)
{
/*
* Try to grow the array.
*
* We can use realloc because shallow copying of the structure is
* okay. Note that the first time through, res->tuples is NULL.
* While ANSI says that realloc() should act like malloc() in that
* case, some old C libraries (like SunOS 4.1.x) coredump instead.
* On failure realloc is supposed to return NULL without damaging
* the existing allocation. Note that the positions beyond
* res->ntups are garbage, not necessarily NULL.
*/
int newSize = (res->tupArrSize > 0) ? res->tupArrSize * 2 : 128;
PGresAttValue **newTuples;
if (res->tuples == NULL)
newTuples = (PGresAttValue **)
malloc(newSize * sizeof(PGresAttValue *));
else
newTuples = (PGresAttValue **)
realloc(res->tuples, newSize * sizeof(PGresAttValue *));
if (!newTuples)
return FALSE; /* malloc or realloc failed */
res->tupArrSize = newSize;
res->tuples = newTuples;
}
res->tuples[res->ntups] = tup;
res->ntups++;
return TRUE;
}
/*
* PQsendQuery
* Submit a query, but don't wait for it to finish
*
* Returns: 1 if successfully submitted
* 0 if error (conn->errorMessage is set)
*/
int
PQsendQuery(PGconn *conn, const char *query)
{
if (!conn)
return 0;
if (!query)
{
sprintf(conn->errorMessage, "PQsendQuery() -- query pointer is null.");
return 0;
}
/* check to see if the query string is too long */
if (strlen(query) > MAX_MESSAGE_LEN - 2)
{
sprintf(conn->errorMessage, "PQsendQuery() -- query is too long. "
"Maximum length is %d\n", MAX_MESSAGE_LEN - 2);
return 0;
}
/* Don't try to send if we know there's no live connection. */
if (conn->status != CONNECTION_OK)
{
sprintf(conn->errorMessage, "PQsendQuery() -- There is no connection "
"to the backend.\n");
return 0;
}
/* Can't send while already busy, either. */
if (conn->asyncStatus != PGASYNC_IDLE)
{
sprintf(conn->errorMessage,
"PQsendQuery() -- another query already in progress.");
return 0;
}
/* clear the error string */
conn->errorMessage[0] = '\0';
/* initialize async result-accumulation state */
conn->result = NULL;
conn->curTuple = NULL;
/* send the query to the backend; */
/* the frontend-backend protocol uses 'Q' to designate queries */
if (pqPutnchar("Q", 1, conn) ||
pqPuts(query, conn) ||
pqFlush(conn))
{
handleSendFailure(conn);
return 0;
}
/* OK, it's launched! */
conn->asyncStatus = PGASYNC_BUSY;
return 1;
}
/*
* handleSendFailure: try to clean up after failure to send command.
*
* Primarily, what we want to accomplish here is to process an async
* NOTICE message that the backend might have sent just before it died.
*
* NOTE: this routine should only be called in PGASYNC_IDLE state.
*/
static void
handleSendFailure(PGconn *conn)
{
/* Preserve the error message emitted by the failing output routine */
char * svErrMsg = strdup(conn->errorMessage);
/*
* Accept any available input data, ignoring errors. Note that if
* pqReadData decides the backend has closed the channel, it will
* close our side of the socket --- that's just what we want here.
*/
while (pqReadData(conn) > 0)
/* loop until no more data readable */ ;
/*
* Parse any available input messages. Since we are in PGASYNC_IDLE
* state, only NOTICE and NOTIFY messages will be eaten.
*/
parseInput(conn);
/* Restore error message generated by output routine, if any. */
if (*svErrMsg != '\0')
strcpy(conn->errorMessage, svErrMsg);
free(svErrMsg);
}
/*
* 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;
/*
* 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)
{
char id;
/*
* Loop to parse successive complete messages available in the buffer.
*/
for (;;)
{
/*
* Quit if in COPY_OUT state: we expect raw data from the server
* until PQendcopy is called. Don't try to parse it according to
* the normal protocol. (This is bogus. The data lines ought to
* be part of the protocol and have identifying leading
* characters.)
*/
if (conn->asyncStatus == PGASYNC_COPY_OUT)
return;
/*
* OK to try to read a message type code.
*/
conn->inCursor = conn->inStart;
if (pqGetc(&id, conn))
return;
/*
* NOTIFY and NOTICE messages can happen in any state besides COPY
* OUT; always process them right away.
*/
if (id == 'A')
{
if (getNotify(conn))
return;
}
else if (id == 'N')
{
if (getNotice(conn))
return;
}
else
{
/*
* Other messages should only be processed while in BUSY
* state. (In particular, in READY state we hold off further
* parsing until the application collects the current
* PGresult.) If the state is IDLE then we got trouble.
*/
if (conn->asyncStatus != PGASYNC_BUSY)
{
if (conn->asyncStatus == PGASYNC_IDLE)
{
sprintf(conn->errorMessage,
"Backend message type 0x%02x arrived while idle\n",
id);
DONOTICE(conn, conn->errorMessage);
/* Discard the unexpected message; good idea?? */
conn->inStart = conn->inEnd;
}
return;
}
switch (id)
{
case 'C': /* command complete */
if (conn->result == NULL)
conn->result = PQmakeEmptyPGresult(conn,
PGRES_COMMAND_OK);
if (pqGets(conn->result->cmdStatus, CMDSTATUS_LEN, conn))
return;
conn->asyncStatus = PGASYNC_READY;
break;
case 'E': /* error return */
if (pqGets(conn->errorMessage, ERROR_MSG_LENGTH, conn))
return;
/* delete any partially constructed result */
pqClearAsyncResult(conn);
/* and build an error result holding the error message */
conn->result = PQmakeEmptyPGresult(conn,
PGRES_FATAL_ERROR);
conn->asyncStatus = PGASYNC_READY;
break;
case 'Z': /* backend is ready for new query */
conn->asyncStatus = PGASYNC_IDLE;
break;
case 'I': /* empty query */
/* read and throw away the closing '\0' */
if (pqGetc(&id, conn))
return;
if (id != '\0')
{
sprintf(conn->errorMessage,
"unexpected character %c following 'I'\n", id);
DONOTICE(conn, conn->errorMessage);
}
if (conn->result == NULL)
conn->result = PQmakeEmptyPGresult(conn,
PGRES_EMPTY_QUERY);
conn->asyncStatus = PGASYNC_READY;
break;
case 'K': /* secret key data from the backend */
/*
* This is expected only during backend startup, but
* it's just as easy to handle it as part of the main
* loop. Save the data and continue processing.
*/
if (pqGetInt(&(conn->be_pid), 4, conn))
return;
if (pqGetInt(&(conn->be_key), 4, conn))
return;
break;
case 'P': /* synchronous (normal) portal */
if (pqGets(conn->errorMessage, ERROR_MSG_LENGTH, conn))
return;
/* We pretty much ignore this message type... */
break;
case 'T': /* row descriptions (start of query
* results) */
if (conn->result == NULL)
{
/* First 'T' in a query sequence */
if (getRowDescriptions(conn))
return;
}
else
{
/*
* A new 'T' message is treated as the start of
* another PGresult. (It is not clear that this
* is really possible with the current backend.)
* We stop parsing until the application accepts
* the current result.
*/
conn->asyncStatus = PGASYNC_READY;
return;
}
break;
case 'D': /* ASCII data tuple */
if (conn->result != NULL)
{
/* Read another tuple of a normal query response */
if (getAnotherTuple(conn, FALSE))
return;
}
else
{
sprintf(conn->errorMessage,
"Backend sent D message without prior T\n");
DONOTICE(conn, conn->errorMessage);
/* Discard the unexpected message; good idea?? */
conn->inStart = conn->inEnd;
return;
}
break;
case 'B': /* Binary data tuple */
if (conn->result != NULL)
{
/* Read another tuple of a normal query response */
if (getAnotherTuple(conn, TRUE))
return;
}
else
{
sprintf(conn->errorMessage,
"Backend sent B message without prior T\n");
DONOTICE(conn, conn->errorMessage);
/* Discard the unexpected message; good idea?? */
conn->inStart = conn->inEnd;
return;
}
break;
case 'G': /* Start Copy In */
conn->asyncStatus = PGASYNC_COPY_IN;
break;
case 'H': /* Start Copy Out */
conn->asyncStatus = PGASYNC_COPY_OUT;
break;
default:
sprintf(conn->errorMessage,
"unknown protocol character '%c' read from backend. "
"(The protocol character is the first character the "
"backend sends in response to a query it receives).\n",
id);
/* Discard the unexpected message; good idea?? */
conn->inStart = conn->inEnd;
/* delete any partially constructed result */
pqClearAsyncResult(conn);
/* and build an error result holding the error message */
conn->result = PQmakeEmptyPGresult(conn,
PGRES_FATAL_ERROR);
conn->asyncStatus = PGASYNC_READY;
return;
} /* switch on protocol character */
}
/* Successfully consumed this message */
conn->inStart = conn->inCursor;
}
}
/*
* parseInput subroutine to read a 'T' (row descriptions) message.
* We build a PGresult structure containing the attribute data.
* Returns: 0 if completed message, EOF if not enough data yet.
*
* Note that if we run out of data, we have to release the partially
* constructed PGresult, and rebuild it again next time. Fortunately,
* that shouldn't happen often, since 'T' messages usually fit in a packet.
*/
static int
getRowDescriptions(PGconn *conn)
{
PGresult *result;
int nfields;
int i;
result = PQmakeEmptyPGresult(conn, PGRES_TUPLES_OK);
/* parseInput already read the 'T' label. */
/* the next two bytes are the number of fields */
if (pqGetInt(&(result->numAttributes), 2, conn))
{
PQclear(result);
return EOF;
}
nfields = result->numAttributes;
/* allocate space for the attribute descriptors */
if (nfields > 0)
{
result->attDescs = (PGresAttDesc *)
pqResultAlloc(result, nfields * sizeof(PGresAttDesc), TRUE);
MemSet((char *) result->attDescs, 0, nfields * sizeof(PGresAttDesc));
}
/* get type info */
for (i = 0; i < nfields; i++)
{
char typName[MAX_MESSAGE_LEN];
int typid;
int typlen;
int atttypmod;
if (pqGets(typName, MAX_MESSAGE_LEN, conn) ||
pqGetInt(&typid, 4, conn) ||
pqGetInt(&typlen, 2, conn) ||
pqGetInt(&atttypmod, 4, conn))
{
PQclear(result);
return EOF;
}
/*
* Since pqGetInt treats 2-byte integers as unsigned, we need to
* coerce the special value "-1" to signed form. (-1 is sent for
* variable-length fields.) Formerly, libpq effectively did a
* sign-extension on the 2-byte value by storing it in a signed
* short. Now we only coerce the single value 65535 == -1; values
* 32768..65534 are taken as valid field lengths.
*/
if (typlen == 0xFFFF)
typlen = -1;
result->attDescs[i].name = pqResultStrdup(result, typName);
result->attDescs[i].typid = typid;
result->attDescs[i].typlen = typlen;
result->attDescs[i].atttypmod = atttypmod;
}
/* Success! */
conn->result = result;
return 0;
}
/*
* parseInput subroutine to read a 'B' or 'D' (row data) message.
* We add another tuple to the existing PGresult structure.
* Returns: 0 if completed message, EOF if error or not enough data yet.
*
* Note that if we run out of data, we have to suspend and reprocess
* the message after more data is received. We keep a partially constructed
* tuple in conn->curTuple, and avoid reallocating already-allocated storage.
*/
static int
getAnotherTuple(PGconn *conn, int binary)
{
PGresult *result = conn->result;
int nfields = result->numAttributes;
PGresAttValue *tup;
char bitmap[MAX_FIELDS]; /* the backend sends us a bitmap
* of which attributes are null */
int i;
int nbytes; /* the number of bytes in bitmap */
char bmap; /* One byte of the bitmap */
int bitmap_index; /* Its index */
int bitcnt; /* number of bits examined in current byte */
int vlen; /* length of the current field value */
result->binary = binary;
/* Allocate tuple space if first time for this data message */
if (conn->curTuple == NULL)
{
conn->curTuple = (PGresAttValue *)
pqResultAlloc(result, nfields * sizeof(PGresAttValue), TRUE);
if (conn->curTuple == NULL)
goto outOfMemory;
MemSet((char *) conn->curTuple, 0, nfields * sizeof(PGresAttValue));
}
tup = conn->curTuple;
/* Get the null-value bitmap */
nbytes = (nfields + BYTELEN - 1) / BYTELEN;
if (nbytes >= MAX_FIELDS)
{
/* Replace partially constructed result with an error result */
pqClearAsyncResult(conn);
sprintf(conn->errorMessage,
"getAnotherTuple() -- null-values bitmap is too large\n");
conn->result = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
conn->asyncStatus = PGASYNC_READY;
/* Discard the broken message */
conn->inStart = conn->inEnd;
return EOF;
}
if (pqGetnchar(bitmap, nbytes, conn))
return EOF;
/* Scan the fields */
bitmap_index = 0;
bmap = bitmap[bitmap_index];
bitcnt = 0;
for (i = 0; i < nfields; i++)
{
if (!(bmap & 0200))
{
/* if the field value is absent, make it a null string */
tup[i].value = result->null_field;
tup[i].len = NULL_LEN;
}
else
{
/* get the value length (the first four bytes are for length) */
if (pqGetInt(&vlen, 4, conn))
return EOF;
if (binary == 0)
vlen = vlen - 4;
if (vlen < 0)
vlen = 0;
if (tup[i].value == NULL)
{
tup[i].value = (char *) pqResultAlloc(result, vlen + 1, binary);
if (tup[i].value == NULL)
goto outOfMemory;
}
tup[i].len = vlen;
/* read in the value */
if (vlen > 0)
if (pqGetnchar((char *) (tup[i].value), vlen, conn))
return EOF;
/* we have to terminate this ourselves */
tup[i].value[vlen] = '\0';
}
/* advance the bitmap stuff */
bitcnt++;
if (bitcnt == BYTELEN)
{
bitmap_index++;
bmap = bitmap[bitmap_index];
bitcnt = 0;
}
else
bmap <<= 1;
}
/* Success! Store the completed tuple in the result */
if (!addTuple(result, tup))
goto outOfMemory;
/* and reset for a new message */
conn->curTuple = NULL;
return 0;
outOfMemory:
/* Replace partially constructed result with an error result */
pqClearAsyncResult(conn);
sprintf(conn->errorMessage,
"getAnotherTuple() -- out of memory for result\n");
conn->result = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
conn->asyncStatus = PGASYNC_READY;
/* Discard the failed message --- good idea? */
conn->inStart = conn->inEnd;
return EOF;
}
/*
* PQisBusy
* Return TRUE if PQgetResult would block waiting for input.
*/
int
PQisBusy(PGconn *conn)
{
if (!conn)
return FALSE;
/* Parse any available data, if our state permits. */
parseInput(conn);
/* PQgetResult will return immediately in all states except BUSY. */
return conn->asyncStatus == PGASYNC_BUSY;
}
/*
* PQgetResult
* Get the next PGresult produced by a query.
* Returns NULL if and only if no query work remains.
*/
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)
{
/* Wait for some more data, and load it. */
if (pqWait(TRUE, FALSE, conn) ||
pqReadData(conn) < 0)
{
pqClearAsyncResult(conn);
conn->asyncStatus = PGASYNC_IDLE;
/* conn->errorMessage has been set by pqWait or pqReadData. */
return PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
}
/* Parse it. */
parseInput(conn);
}
/* Return the appropriate thing. */
switch (conn->asyncStatus)
{
case PGASYNC_IDLE:
res = NULL; /* query is complete */
break;
case PGASYNC_READY:
/*
* 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;
conn->result = NULL;/* handing over ownership to caller */
conn->curTuple = NULL; /* just in case */
if (!res)
res = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
else
{
/*
* Make sure PQerrorMessage agrees with result; it could
* be that we have done other operations that changed
* errorMessage since the result's error message was
* saved.
*/
strcpy(conn->errorMessage, PQresultErrorMessage(res));
}
/* Set the state back to BUSY, allowing parsing to proceed. */
conn->asyncStatus = PGASYNC_BUSY;
break;
case PGASYNC_COPY_IN:
res = PQmakeEmptyPGresult(conn, PGRES_COPY_IN);
break;
case PGASYNC_COPY_OUT:
res = PQmakeEmptyPGresult(conn, PGRES_COPY_OUT);
break;
default:
sprintf(conn->errorMessage,
"PQgetResult: Unexpected asyncStatus %d\n",
(int) conn->asyncStatus);
res = PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
break;
}
return res;
}
/*
* 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)
{
PGresult *result;
PGresult *lastResult;
/*
* 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)
{
if (result->resultStatus == PGRES_COPY_IN ||
result->resultStatus == PGRES_COPY_OUT)
{
PQclear(result);
sprintf(conn->errorMessage,
"PQexec: you gotta get out of a COPY state yourself.\n");
return NULL;
}
PQclear(result);
}
/* OK to send the message */
if (!PQsendQuery(conn, query))
return NULL;
/*
* For backwards compatibility, return the last result if there are
* more than one. We have to stop if we see copy in/out, however. We
* will resume parsing when application calls PQendcopy.
*/
lastResult = NULL;
while ((result = PQgetResult(conn)) != NULL)
{
if (lastResult)
PQclear(lastResult);
lastResult = result;
if (result->resultStatus == PGRES_COPY_IN ||
result->resultStatus == PGRES_COPY_OUT)
break;
}
return lastResult;
}
/*
* Attempt to read a Notice response message.
* This is possible in several places, so we break it out as a subroutine.
* Entry: 'N' flag character has already been consumed.
* Exit: returns 0 if successfully consumed Notice message.
* returns EOF if not enough data.
*/
static int
getNotice(PGconn *conn)
{
if (pqGets(conn->errorMessage, ERROR_MSG_LENGTH, conn))
return EOF;
DONOTICE(conn, conn->errorMessage);
return 0;
}
/*
* Attempt to read a Notify response message.
* This is possible in several places, so we break it out as a subroutine.
* Entry: 'A' flag character has already been consumed.
* Exit: returns 0 if successfully consumed Notify message.
* returns EOF if not enough data.
*/
static int
getNotify(PGconn *conn)
{
PGnotify tempNotify;
PGnotify *newNotify;
if (pqGetInt(&(tempNotify.be_pid), 4, conn))
return EOF;
if (pqGets(tempNotify.relname, NAMEDATALEN, conn))
return EOF;
newNotify = (PGnotify *) malloc(sizeof(PGnotify));
memcpy(newNotify, &tempNotify, sizeof(PGnotify));
DLAddTail(conn->notifyList, DLNewElem(newNotify));
return 0;
}
/*
* PQnotifies
* returns a PGnotify* structure of the latest async notification
* that has not yet been handled
*
* returns NULL, if there is currently
* no unhandled async notification from the backend
*
* the CALLER is responsible for FREE'ing the structure returned
*/
PGnotify *
PQnotifies(PGconn *conn)
{
Dlelem *e;
PGnotify *event;
if (!conn)
return NULL;
/* Parse any available data to see if we can extract NOTIFY messages. */
parseInput(conn);
/* RemHead returns NULL if list is empty */
e = DLRemHead(conn->notifyList);
if (!e)
return NULL;
event = (PGnotify *) DLE_VAL(e);
DLFreeElem(e);
return event;
}
/*
* 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.
*
* 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 it is detected or 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)
{
int result = 1; /* return value if buffer overflows */
if (!s || maxlen <= 0)
return EOF;
if (!conn || conn->sock < 0)
{
*s = '\0';
return EOF;
}
/*
* Since this is a purely synchronous routine, we don't bother to
* maintain conn->inCursor; there is no need to back up.
*/
while (maxlen > 1)
{
if (conn->inStart < conn->inEnd)
{
char c = conn->inBuffer[conn->inStart++];
if (c == '\n')
{
result = 0; /* success exit */
break;
}
*s++ = c;
maxlen--;
}
else
{
/* need to load more data */
if (pqWait(TRUE, FALSE, conn) ||
pqReadData(conn) < 0)
{
result = EOF;
break;
}
}
}
*s = '\0';
return result;
}
/*
* PQgetlineAsync - gets a newline-terminated string 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 newline-
* terminated data line is available in libpq's input buffer, or if the
* incoming data line is too long to fit in the buffer offered by the caller.
* Otherwise, no data is returned until the rest of the line 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 newline character. If possible
* a whole line will be returned at one time. But if the buffer offered by
* the caller is too small to hold a line sent by the backend, then a partial
* data line will be returned. This can be detected by testing whether the
* last returned byte is '\n' or not.
* The returned string is *not* null-terminated.
*/
int
PQgetlineAsync(PGconn *conn, char *buffer, int bufsize)
{
int avail;
if (!conn || conn->asyncStatus != PGASYNC_COPY_OUT)
return -1; /* we are not doing a copy... */
/*
* Move data from libpq's buffer to the caller's. We want to accept
* data only in units of whole lines, not partial lines. This ensures
* that we can recognize the terminator line "\\.\n". (Otherwise, if
* it happened to cross a packet/buffer boundary, we might hand the
* first one or two characters off to the caller, which we shouldn't.)
*/
conn->inCursor = conn->inStart;
avail = bufsize;
while (avail > 0 && conn->inCursor < conn->inEnd)
{
char c = conn->inBuffer[conn->inCursor++];
*buffer++ = c;
--avail;
if (c == '\n')
{
/* Got a complete line; mark the data removed from libpq */
conn->inStart = conn->inCursor;
/* Is it the endmarker line? */
if (bufsize - avail == 3 && buffer[-3] == '\\' && buffer[-2] == '.')
return -1;
/* No, return the data line to the caller */
return bufsize - avail;
}
}
/*
* We don't have a complete line. We'd prefer to leave it in libpq's
* buffer until the rest arrives, but there is a special case: what if
* the line is longer than the buffer the caller is offering us? In
* that case we'd better hand over a partial line, else we'd get into
* an infinite loop. Do this in a way that ensures we can't
* misrecognize a terminator line later: leave last 3 characters in
* libpq buffer.
*/
if (avail == 0 && bufsize > 3)
{
conn->inStart = conn->inCursor - 3;
return bufsize - 3;
}
return 0;
}
/*
* PQputline -- sends a string to the backend.
* Returns 0 if OK, EOF if not.
*
* Chiefly here so that applications can use "COPY <rel> from stdin".
*/
int
PQputline(PGconn *conn, const char *s)
{
if (!conn || conn->sock < 0)
return EOF;
return pqPutnchar(s, strlen(s), conn);
}
/*
* 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 (!conn || conn->sock < 0)
return EOF;
return pqPutnchar(buffer, nbytes, conn);
}
/*
* PQendcopy
* After completing the data transfer portion of a copy in/out,
* the application must call this routine to finish the command protocol.
*
* RETURNS:
* 0 on success
* 1 on failure
*/
int
PQendcopy(PGconn *conn)
{
PGresult *result;
if (!conn)
return 0;
if (conn->asyncStatus != PGASYNC_COPY_IN &&
conn->asyncStatus != PGASYNC_COPY_OUT)
{
sprintf(conn->errorMessage,
"PQendcopy() -- I don't think there's a copy in progress.");
return 1;
}
(void) pqFlush(conn); /* make sure no data is waiting to be sent */
/* Return to active duty */
conn->asyncStatus = PGASYNC_BUSY;
conn->errorMessage[0] = '\0';
/* Wait for the completion response */
result = PQgetResult(conn);
/* Expecting a successful result */
if (result && result->resultStatus == PGRES_COMMAND_OK)
{
PQclear(result);
return 0;
}
/*
* Trouble. The worst case is that we've lost sync with the backend
* entirely due to application screwup of the copy in/out protocol. To
* recover, reset the connection (talk about using a sledgehammer...)
*/
PQclear(result);
if (conn->errorMessage[0])
DONOTICE(conn, conn->errorMessage);
DONOTICE(conn, "PQendcopy: resetting connection\n");
PQreset(conn);
return 1;
}
/* ----------------
* PQfn - Send a function call to the POSTGRES backend.
*
* conn : backend connection
* fnid : function id
* result_buf : pointer to result buffer (&int if integer)
* result_len : length of return value.
* actual_result_len: actual length returned. (differs from result_len
* for varlena structures.)
* result_type : 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.
* *actual_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 *actual_result_len,
int result_is_int,
PQArgBlock *args,
int nargs)
{
bool needInput = false;
ExecStatusType status = PGRES_FATAL_ERROR;
char id;
int i;
*actual_result_len = 0;
printf("fe-exec, PQfn, A\n");
if (!conn)
return NULL;
if (conn->sock < 0 || conn->asyncStatus != PGASYNC_IDLE)
{
printf("fe-exec, PQfn, B\n");
sprintf(conn->errorMessage, "PQfn() -- connection in wrong state\n");
return NULL;
}
/* clear the error string */
conn->errorMessage[0] = '\0';
if (pqPuts("F ", conn) || /* function */
pqPutInt(fnid, 4, conn) || /* function id */
pqPutInt(nargs, 4, conn)) /* # of args */
{
printf("fe-exec, PQfn, C\n");
handleSendFailure(conn);
return NULL;
}
for (i = 0; i < nargs; ++i)
{ /* len.int4 + contents */
printf("fe-exec, PQfn, C: i:%d\n",i);
if (pqPutInt(args[i].len, 4, conn))
{
printf("fe-exec, PQfn, D\n");
handleSendFailure(conn);
return NULL;
}
if (args[i].isint)
{
printf("fe-exec, PQfn, E\n");
if (pqPutInt(args[i].u.integer, 4, conn))
{
printf("fe-exec, PQfn, F\n");
handleSendFailure(conn);
return NULL;
}
}
else
{
printf("fe-exec, PQfn, G\n");
if (pqPutnchar((char *) args[i].u.ptr, args[i].len, conn))
{
handleSendFailure(conn);
return NULL;
}
}
}
if (pqFlush(conn))
{
printf("fe-exec, PQfn, H\n");
handleSendFailure(conn);
return NULL;
}
for (;;)
{
printf("fe-exec, PQfn, I\n");
if (needInput)
{
printf("fe-exec, PQfn, J\n");
/* Wait for some data to arrive (or for the channel to close) */
if (pqWait(TRUE, FALSE, conn) ||
pqReadData(conn) < 0)
break;
}
/*
* Scan the message. If we run out of data, loop around to try
* again.
*/
conn->inCursor = conn->inStart;
needInput = true;
if (pqGetc(&id, conn))
{
printf("fe-exec, PQfn, J1: %c\n",id);
continue;
}
/*
* We should see V or E response to the command, but might get N
* and/or A notices first. We also need to swallow the final Z
* before returning.
*/
printf("fe-exec, PQfn, ID: %c\n", id);
switch (id)
{
case 'V': /* function result */
printf("fe-exec, PQfn, 0\n");
if (pqGetc(&id, conn))
continue;
printf("fe-exec, PQfn, 1\n");
if (id == 'G')
{
printf("fe-exec, PQfn, 2\n");
/* function returned nonempty value */
if (pqGetInt(actual_result_len, 4, conn))
continue;
if (result_is_int)
{
printf("fe-exec, PQfn, 3: %d\n",*actual_result_len);
if (pqGetInt(result_buf, 4, conn))
{
printf("fe-exec, PQfn, 3a: result_buf: %lu\n", *result_buf);
continue;
}
printf("fe-exec, PQfn, 3b: result_buf: %lu\n", *result_buf);
}
else
{
printf("fe-exec, PQfn, 4\n");
if (pqGetnchar((char *) result_buf,
*actual_result_len,
conn))
continue;
}
if (pqGetc(&id, conn)) /* get the last '0' */
{
printf("fe-exec, PQfn, 4a\n");
continue;
}
}
if (id == '0')
{
printf("fe-exec, PQfn, 5\n");
/* correctly finished function result message */
status = PGRES_COMMAND_OK;
}
else
{
printf("fe-exec, PQfn, 6\n");
/* The backend violates the protocol. */
sprintf(conn->errorMessage,
"FATAL: PQfn: protocol error: id=%x\n", id);
conn->inStart = conn->inCursor;
return PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
}
break;
case 'E': /* error return */
if (pqGets(conn->errorMessage, ERROR_MSG_LENGTH, conn))
continue;
status = PGRES_FATAL_ERROR;
break;
case 'A': /* notify message */
/* handle notify and go back to processing return values */
if (getNotify(conn))
continue;
break;
case 'N': /* notice */
/* handle notice and go back to processing return values */
if (getNotice(conn))
continue;
break;
case 'Z': /* backend is ready for new query */
/* consume the message and exit */
conn->inStart = conn->inCursor;
return PQmakeEmptyPGresult(conn, status);
default:
/* The backend violates the protocol. */
sprintf(conn->errorMessage,
"FATAL: PQfn: protocol error: id=%x\n", id);
conn->inStart = conn->inCursor;
return PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
}
/* Completed this message, keep going */
conn->inStart = conn->inCursor;
needInput = false;
}
/* we fall out of the loop only upon failing to read data */
return PQmakeEmptyPGresult(conn, PGRES_FATAL_ERROR);
}
/* ====== accessor funcs for PGresult ======== */
ExecStatusType
PQresultStatus(PGresult *res)
{
if (!res)
return PGRES_NONFATAL_ERROR;
return res->resultStatus;
}
const char *
PQresStatus(ExecStatusType status)
{
if (((int) status) < 0 ||
((int) status) >= (sizeof(pgresStatus) / sizeof(pgresStatus[0])))
return "Invalid ExecStatusType code";
return pgresStatus[status];
}
const char *
PQresultErrorMessage(PGresult *res)
{
if (!res || !res->errMsg)
return "";
return res->errMsg;
}
int
PQntuples(PGresult *res)
{
if (!res)
return 0;
return res->ntups;
}
int
PQnfields(PGresult *res)
{
if (!res)
return 0;
return res->numAttributes;
}
int
PQbinaryTuples(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 char *routineName, PGresult *res, int field_num)
{
if (!res)
return FALSE; /* no way to display error message... */
if (field_num < 0 || field_num >= res->numAttributes)
{
if (res->conn)
{
sprintf(res->conn->errorMessage,
"%s: ERROR! field number %d is out of range 0..%d\n",
routineName, field_num, res->numAttributes - 1);
DONOTICE(res->conn, res->conn->errorMessage);
}
return FALSE;
}
return TRUE;
}
static int
check_tuple_field_number(const char *routineName, 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)
{
if (res->conn)
{
sprintf(res->conn->errorMessage,
"%s: ERROR! tuple number %d is out of range 0..%d\n",
routineName, tup_num, res->ntups - 1);
DONOTICE(res->conn, res->conn->errorMessage);
}
return FALSE;
}
if (field_num < 0 || field_num >= res->numAttributes)
{
if (res->conn)
{
sprintf(res->conn->errorMessage,
"%s: ERROR! field number %d is out of range 0..%d\n",
routineName, field_num, res->numAttributes - 1);
DONOTICE(res->conn, res->conn->errorMessage);
}
return FALSE;
}
return TRUE;
}
/*
returns NULL if the field_num is invalid
*/
char *
PQfname(PGresult *res, int field_num)
{
if (!check_field_number("PQfname", res, field_num))
return NULL;
if (res->attDescs)
return res->attDescs[field_num].name;
else
return NULL;
}
/*
returns -1 on a bad field name
*/
int
PQfnumber(PGresult *res, const char *field_name)
{
int i;
char *field_case;
if (!res)
return -1;
if (field_name == NULL ||
field_name[0] == '\0' ||
res->attDescs == NULL)
return -1;
field_case = strdup(field_name);
if (*field_case == '"')
{
strcpy(field_case, field_case + 1);
*(field_case + strlen(field_case) - 1) = '\0';
}
else
for (i = 0; field_case[i]; i++)
if (isascii((unsigned char) field_case[i]) &&
isupper(field_case[i]))
field_case[i] = tolower(field_case[i]);
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
PQftype(PGresult *res, int field_num)
{
if (!check_field_number("PQftype", res, field_num))
return InvalidOid;
if (res->attDescs)
return res->attDescs[field_num].typid;
else
return InvalidOid;
}
int
PQfsize(PGresult *res, int field_num)
{
if (!check_field_number("PQfsize", res, field_num))
return 0;
if (res->attDescs)
return res->attDescs[field_num].typlen;
else
return 0;
}
int
PQfmod(PGresult *res, int field_num)
{
if (!check_field_number("PQfmod", 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 ""
*/
const char *
PQoidStatus(PGresult *res)
{
char *p,
*e,
*scan;
int slen,
olen;
if (!res)
return "";
if (strncmp(res->cmdStatus, "INSERT ", 7) != 0)
return "";
/*----------
* The cmdStatus string looks like
* INSERT oid count\0
* In order to be able to return an ordinary C string without
* damaging the result for PQcmdStatus or PQcmdTuples, we copy
* the oid part of the string to just after the null, so that
* cmdStatus looks like
* INSERT oid count\0oid\0
* ^ our return value points here
* Pretty klugy eh? This routine should've just returned an Oid value.
*----------
*/
slen = strlen(res->cmdStatus);
p = res->cmdStatus + 7; /* where oid is now */
e = res->cmdStatus + slen + 1; /* where to put the oid string */
for (scan = p; *scan && *scan != ' ';)
scan++;
olen = scan - p;
if (slen + olen + 2 > sizeof(res->cmdStatus))
return ""; /* something very wrong if it doesn't fit */
strncpy(e, p, olen);
e[olen] = '\0';
return e;
}
/*
PQcmdTuples -
if the last command was an INSERT/UPDATE/DELETE, return number
of inserted/affected tuples, if not, return ""
*/
const char *
PQcmdTuples(PGresult *res)
{
if (!res)
return "";
if (strncmp(res->cmdStatus, "INSERT", 6) == 0 ||
strncmp(res->cmdStatus, "DELETE", 6) == 0 ||
strncmp(res->cmdStatus, "UPDATE", 6) == 0)
{
char *p = res->cmdStatus + 6;
if (*p == 0)
{
if (res->conn)
{
sprintf(res->conn->errorMessage,
"PQcmdTuples (%s) -- bad input from server\n",
res->cmdStatus);
DONOTICE(res->conn, res->conn->errorMessage);
}
return "";
}
p++;
if (*(res->cmdStatus) != 'I') /* UPDATE/DELETE */
return p;
while (*p != ' ' && *p)
p++; /* INSERT: skip oid */
if (*p == 0)
{
if (res->conn)
{
sprintf(res->conn->errorMessage,
"PQcmdTuples (INSERT) -- there's no # of tuples\n");
DONOTICE(res->conn, res->conn->errorMessage);
}
return "";
}
p++;
return p;
}
return "";
}
/*
PQgetvalue:
return the value of field 'field_num' of row 'tup_num'
If res is binary, then the value returned is NOT a null-terminated
ASCII string, but the binary representation in the server's native
format.
if res is not binary, a null-terminated ASCII string is returned.
*/
char *
PQgetvalue(PGresult *res, int tup_num, int field_num)
{
if (!check_tuple_field_number("PQgetvalue", res, tup_num, field_num))
return NULL;
return res->tuples[tup_num][field_num].value;
}
/* PQgetlength:
returns the length of a field value in bytes. If res is binary,
i.e. a result of a binary portal, then the length returned does
NOT include the size field of the varlena. (The data returned
by PQgetvalue doesn't either.)
*/
int
PQgetlength(PGresult *res, int tup_num, int field_num)
{
if (!check_tuple_field_number("PQgetlength", 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(PGresult *res, int tup_num, int field_num)
{
if (!check_tuple_field_number("PQgetisnull", 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;
}
/*-------------------------------------------------------------------------
*
* fe-lobj.c
* Front-end large object interface
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /usr/local/cvsroot/pgsql/src/interfaces/libpq/fe-lobj.c,v 1.20 1999/05/10 00:46:26 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include "libpq-fe.h"
#include "libpq-int.h"
#include "postgres.h"
#ifdef WIN32
#include "win32.h"
#include <io.h>
#else
#if !defined(NO_UNISTD_H)
#include <unistd.h>
#endif
#endif
#include <string.h>
#include <fcntl.h>
#include <sys/stat.h>
#include "libpq/libpq-fs.h" /* must come after sys/stat.h */
#define LO_BUFSIZE 1024
static int lo_initialize(PGconn *conn);
/*
* lo_open
* opens an existing large object
*
* returns the file descriptor for use in later lo_* calls
* return -1 upon failure.
*/
int
lo_open(PGconn *conn, Oid lobjId, int mode)
{
int fd;
int result_len;
PQArgBlock argv[2];
PGresult *res;
argv[0].isint = 1;
argv[0].len = 4;
argv[0].u.integer = lobjId;
argv[1].isint = 1;
argv[1].len = 4;
argv[1].u.integer = mode;
printf("fe-lobj, lo_open: 0\n");
if (conn->lobjfuncs == (PGlobjfuncs *) NULL)
{
printf("fe-lobj, lo_open: 1\n");
if (lo_initialize(conn) < 0)
return -1;
}
printf("fe-lobj, lo_open: 1a\n");
res = PQfn(conn, conn->lobjfuncs->fn_lo_open, &fd, &result_len, 1, argv, 2);
printf("fe-lobj, lo_open: 2 (%x,%x)\n",conn->lobjfuncs->fn_lo_open,fd);
if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
int WN_TEMP;
printf("fe-lobj, lo_open: 3\n");
PQclear(res);
/* have to do this to reset offset in shared fd cache */
/* but only if fd is valid */
if (fd >= 0 && (WN_TEMP = lo_lseek(conn, fd, 0L, SEEK_SET)) < 0)
{
printf("fe-lobj, lo_open: 3a (%x,%x)\n",fd,WN_TEMP);
return -1;
}
printf("fe-lobj, lo_open: 3b\n");
return fd;
}
else
{
printf("fe-lobj, lo_open: 4\n");
PQclear(res);
return -1;
}
}
/*
* lo_close
* closes an existing large object
*
* returns 0 upon success
* returns -1 upon failure.
*/
int
lo_close(PGconn *conn, int fd)
{
PQArgBlock argv[1];
PGresult *res;
int retval;
int result_len;
if (conn->lobjfuncs == (PGlobjfuncs *) NULL)
{
if (lo_initialize(conn) < 0)
return -1;
}
argv[0].isint = 1;
argv[0].len = 4;
argv[0].u.integer = fd;
res = PQfn(conn, conn->lobjfuncs->fn_lo_close,
&retval, &result_len, 1, argv, 1);
if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
PQclear(res);
return retval;
}
else
{
PQclear(res);
return -1;
}
}
/*
* lo_read
* read len bytes of the large object into buf
*
* returns the length of bytes read.
* the CALLER must have allocated enough space to hold the result returned
*/
int
lo_read(PGconn *conn, int fd, char *buf, int len)
{
PQArgBlock argv[2];
PGresult *res;
int result_len;
if (conn->lobjfuncs == (PGlobjfuncs *) NULL)
{
if (lo_initialize(conn) < 0)
return -1;
}
argv[0].isint = 1;
argv[0].len = 4;
argv[0].u.integer = fd;
argv[1].isint = 1;
argv[1].len = 4;
argv[1].u.integer = len;
res = PQfn(conn, conn->lobjfuncs->fn_lo_read,
(int *) buf, &result_len, 0, argv, 2);
if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
PQclear(res);
return result_len;
}
else
{
PQclear(res);
return -1;
}
}
/*
* lo_write
* write len bytes of buf into the large object fd
*
*/
int
lo_write(PGconn *conn, int fd, char *buf, int len)
{
PQArgBlock argv[2];
PGresult *res;
int result_len;
int retval;
if (conn->lobjfuncs == (PGlobjfuncs *) NULL)
{
if (lo_initialize(conn) < 0)
return -1;
}
if (len <= 0)
return 0;
argv[0].isint = 1;
argv[0].len = 4;
argv[0].u.integer = fd;
argv[1].isint = 0;
argv[1].len = len;
argv[1].u.ptr = (int *) buf;
res = PQfn(conn, conn->lobjfuncs->fn_lo_write,
&retval, &result_len, 1, argv, 2);
if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
PQclear(res);
return retval;
}
else
{
PQclear(res);
return -1;
}
}
/*
* lo_lseek
* change the current read or write location on a large object
* currently, only L_SET is a legal value for whence
*
*/
int
lo_lseek(PGconn *conn, int fd, int offset, int whence)
{
PQArgBlock argv[3];
PGresult *res;
int retval;
int result_len;
if (conn->lobjfuncs == (PGlobjfuncs *) NULL)
{
if (lo_initialize(conn) < 0)
return -1;
}
argv[0].isint = 1;
argv[0].len = 4;
argv[0].u.integer = fd;
argv[1].isint = 1;
argv[1].len = 4;
argv[1].u.integer = offset;
argv[2].isint = 1;
argv[2].len = 4;
argv[2].u.integer = whence;
res = PQfn(conn, conn->lobjfuncs->fn_lo_lseek,
&retval, &result_len, 1, argv, 3);
if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
PQclear(res);
return retval;
}
else
{
PQclear(res);
return -1;
}
}
/*
* lo_creat
* create a new large object
* the mode is a bitmask describing different attributes of the new object
*
* returns the oid of the large object created or
* InvalidOid upon failure
*/
Oid
lo_creat(PGconn *conn, int mode)
{
PQArgBlock argv[1];
PGresult *res;
int retval;
int result_len;
if (conn->lobjfuncs == (PGlobjfuncs *) NULL)
{
if (lo_initialize(conn) < 0)
return -1;
}
argv[0].isint = 1;
argv[0].len = 4;
argv[0].u.integer = mode;
res = PQfn(conn, conn->lobjfuncs->fn_lo_creat,
&retval, &result_len, 1, argv, 1);
if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
PQclear(res);
return (Oid) retval;
}
else
{
PQclear(res);
return InvalidOid;
}
}
/*
* lo_tell
* returns the current seek location of the large object
*
*/
int
lo_tell(PGconn *conn, int fd)
{
int retval;
PQArgBlock argv[1];
PGresult *res;
int result_len;
if (conn->lobjfuncs == (PGlobjfuncs *) NULL)
{
if (lo_initialize(conn) < 0)
return -1;
}
argv[0].isint = 1;
argv[0].len = 4;
argv[0].u.integer = fd;
res = PQfn(conn, conn->lobjfuncs->fn_lo_tell,
&retval, &result_len, 1, argv, 1);
if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
PQclear(res);
return retval;
}
else
{
PQclear(res);
return -1;
}
}
/*
* lo_unlink
* delete a file
*
*/
int
lo_unlink(PGconn *conn, Oid lobjId)
{
PQArgBlock argv[1];
PGresult *res;
int result_len;
int retval;
if (conn->lobjfuncs == (PGlobjfuncs *) NULL)
{
if (lo_initialize(conn) < 0)
return -1;
}
argv[0].isint = 1;
argv[0].len = 4;
argv[0].u.integer = lobjId;
res = PQfn(conn, conn->lobjfuncs->fn_lo_unlink,
&retval, &result_len, 1, argv, 1);
if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
PQclear(res);
return retval;
}
else
{
PQclear(res);
return -1;
}
}
/*
* lo_import -
* imports a file as an (inversion) large object.
* returns the oid of that object upon success,
* returns InvalidOid upon failure
*
*/
Oid
lo_import(PGconn *conn, char *filename)
{
int fd;
int nbytes,
tmp;
char buf[LO_BUFSIZE];
Oid lobjOid;
int lobj;
/*
* open the file to be read in
*/
#ifndef __CYGWIN32__
fd = open(filename, O_RDONLY, 0666);
#else
fd = open(filename, O_RDONLY | O_BINARY, 0666);
#endif
if (fd < 0)
{ /* error */
sprintf(conn->errorMessage,
"lo_import: can't open unix file\"%s\"\n", filename);
return InvalidOid;
}
/*
* create an inversion "object"
*/
lobjOid = lo_creat(conn, INV_READ | INV_WRITE);
if (lobjOid == InvalidOid)
{
sprintf(conn->errorMessage,
"lo_import: can't create inv object for \"%s\"", filename);
return InvalidOid;
}
lobj = lo_open(conn, lobjOid, INV_WRITE);
if (lobj == -1)
{
sprintf(conn->errorMessage,
"lo_import: could not open inv object oid %u", lobjOid);
return InvalidOid;
}
/*
* read in from the Unix file and write to the inversion file
*/
while ((nbytes = read(fd, buf, LO_BUFSIZE)) > 0)
{
tmp = lo_write(conn, lobj, buf, nbytes);
if (tmp < nbytes)
{
sprintf(conn->errorMessage,
"lo_import: error while reading \"%s\"", filename);
return InvalidOid;
}
}
(void) close(fd);
(void) lo_close(conn, lobj);
return lobjOid;
}
/*
* lo_export -
* exports an (inversion) large object.
* returns -1 upon failure, 1 otherwise
*/
int
lo_export(PGconn *conn, Oid lobjId, char *filename)
{
int fd;
int nbytes,
tmp;
char buf[LO_BUFSIZE];
int lobj;
/*
* create an inversion "object"
*/
lobj = lo_open(conn, lobjId, INV_READ);
if (lobj == -1)
{
sprintf(conn->errorMessage,
"lo_export: can't open inv object %u", lobjId);
return -1;
}
/*
* open the file to be written to
*/
#ifndef __CYGWIN32__
fd = open(filename, O_CREAT | O_WRONLY | O_TRUNC, 0666);
#else
fd = open(filename, O_CREAT | O_WRONLY | O_TRUNC | O_BINARY, 0666);
#endif
if (fd < 0)
{ /* error */
sprintf(conn->errorMessage,
"lo_export: can't open unix file\"%s\"", filename);
return 0;
}
/*
* read in from the Unix file and write to the inversion file
*/
while ((nbytes = lo_read(conn, lobj, buf, LO_BUFSIZE)) > 0)
{
tmp = write(fd, buf, nbytes);
if (tmp < nbytes)
{
sprintf(conn->errorMessage,
"lo_export: error while writing \"%s\"",
filename);
return -1;
}
}
(void) lo_close(conn, lobj);
(void) close(fd);
return 1;
}
/* ----------------
* lo_initialize
*
* Initialize the large object interface for an existing connection.
* We ask the backend about the functions OID's in pg_proc for all
* functions that are required for large object operations.
* ----------------
*/
static int
lo_initialize(PGconn *conn)
{
PGresult *res;
PGlobjfuncs *lobjfuncs;
int n;
char *fname;
Oid foid;
/* ----------------
* Allocate the structure to hold the functions OID's
* ----------------
*/
lobjfuncs = (PGlobjfuncs *) malloc(sizeof(PGlobjfuncs));
if (lobjfuncs == (PGlobjfuncs *) NULL)
{
strcpy(conn->errorMessage,
"FATAL: malloc() failed in lo_initialize()\n");
return -1;
}
MemSet((char *) lobjfuncs, 0, sizeof(PGlobjfuncs));
/* ----------------
* Execute the query to get all the functions at once
* ----------------
*/
res = PQexec(conn, "select proname, oid from pg_proc \
where proname = 'lo_open' \
or proname = 'lo_close' \
or proname = 'lo_creat' \
or proname = 'lo_unlink' \
or proname = 'lo_lseek' \
or proname = 'lo_tell' \
or proname = 'loread' \
or proname = 'lowrite'");
if (res == (PGresult *) NULL)
{
free(lobjfuncs);
return -1;
}
if (res->resultStatus != PGRES_TUPLES_OK)
{
free(lobjfuncs);
PQclear(res);
strcpy(conn->errorMessage,
"ERROR: SELECT didn't return data in lo_initialize()\n");
return -1;
}
/* ----------------
* Examine the result and put the OID's into the struct
* ----------------
*/
for (n = 0; n < PQntuples(res); n++)
{
fname = PQgetvalue(res, n, 0);
foid = (Oid) atoi(PQgetvalue(res, n, 1));
if (!strcmp(fname, "lo_open"))
lobjfuncs->fn_lo_open = foid;
else if (!strcmp(fname, "lo_close"))
lobjfuncs->fn_lo_close = foid;
else if (!strcmp(fname, "lo_creat"))
lobjfuncs->fn_lo_creat = foid;
else if (!strcmp(fname, "lo_unlink"))
lobjfuncs->fn_lo_unlink = foid;
else if (!strcmp(fname, "lo_lseek"))
lobjfuncs->fn_lo_lseek = foid;
else if (!strcmp(fname, "lo_tell"))
lobjfuncs->fn_lo_tell = foid;
else if (!strcmp(fname, "loread"))
lobjfuncs->fn_lo_read = foid;
else if (!strcmp(fname, "lowrite"))
lobjfuncs->fn_lo_write = foid;
}
PQclear(res);
/* ----------------
* Finally check that we really got all large object
* interface functions.
* ----------------
*/
if (lobjfuncs->fn_lo_open == 0)
{
strcpy(conn->errorMessage,
"ERROR: Cannot determine OID for function lo_open\n");
free(lobjfuncs);
return -1;
}
if (lobjfuncs->fn_lo_close == 0)
{
strcpy(conn->errorMessage,
"ERROR: Cannot determine OID for function lo_close\n");
free(lobjfuncs);
return -1;
}
if (lobjfuncs->fn_lo_creat == 0)
{
strcpy(conn->errorMessage,
"ERROR: Cannot determine OID for function lo_creat\n");
free(lobjfuncs);
return -1;
}
if (lobjfuncs->fn_lo_unlink == 0)
{
strcpy(conn->errorMessage,
"ERROR: Cannot determine OID for function lo_unlink\n");
free(lobjfuncs);
return -1;
}
if (lobjfuncs->fn_lo_lseek == 0)
{
strcpy(conn->errorMessage,
"ERROR: Cannot determine OID for function lo_lseek\n");
free(lobjfuncs);
return -1;
}
if (lobjfuncs->fn_lo_tell == 0)
{
strcpy(conn->errorMessage,
"ERROR: Cannot determine OID for function lo_tell\n");
free(lobjfuncs);
return -1;
}
if (lobjfuncs->fn_lo_read == 0)
{
strcpy(conn->errorMessage,
"ERROR: Cannot determine OID for function loread\n");
free(lobjfuncs);
return -1;
}
if (lobjfuncs->fn_lo_write == 0)
{
strcpy(conn->errorMessage,
"ERROR: Cannot determine OID for function lowrite\n");
free(lobjfuncs);
return -1;
}
/* ----------------
* Put the structure into the connection control
* ----------------
*/
conn->lobjfuncs = lobjfuncs;
return 0;
}
FindExec: found "/usr/local/postgres/bin/postgres" using argv[0]
binding ShmemCreate(key=52e2c1, size=1063936)
/usr/local/postgres/bin/postmaster: ServerLoop: handling reading 4
/usr/local/postgres/bin/postmaster: ServerLoop: handling reading 4
/usr/local/postgres/bin/postmaster: ServerLoop: handling writing 4
/usr/local/postgres/bin/postmaster: BackendStartup: environ dump:
-----------------------------------------
REMOTEHOST=baikonur.home.hottis.intern
HZ=100
HOSTNAME=talshiar
PS1=\h:\w\$
USER=postgres
MACHTYPE=i486-pc-linux-gnu
MAIL=/var/spool/mail/wn
DISPLAY=imhotep:0.0
LOGNAME=postgres
SHLVL=3
HUSHLOGIN=FALSE
SHELL=/bin/bash
PGLIB=/usr/local/postgres/lib
HOSTTYPE=i486
OSTYPE=linux-gnu
TERM=xterm
HOME=/var/local/postgres/home
PGDATA=/var/local/postgres/data
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/X11R6/bin:/usr/local/postgres/bin:/usr/local/samba/bin
_=/usr/local/postgres/bin/postmaster
POSTPORT=5432
POSTID=2147483647
PG_USER=wn
IPC_KEY=5432000
-----------------------------------------
/usr/local/postgres/bin/postmaster: BackendStartup: pid 13256 user wn db adrema socket 4
/usr/local/postgres/bin/postmaster child[13256]: starting with (/usr/local/postgres/bin/postgres -d3 -v131072 -p adrema
)
FindExec: found "/usr/local/postgres/bin/postgres" using argv[0]
debug info:
User = wn
RemoteHost = localhost
RemotePort = 0
DatabaseName = adrema
Verbose = 3
Noversion = f
timings = f
dates = Normal
bufsize = 64
sortmem = 512
query echo = f
InitPostgres
StartTransactionCommand
NOTICE: WN: xact: StartTransaction
query: select proname, oid from pg_proc where proname = 'lo_open' or proname = 'lo_close' or proname = 'lo_creat' or
proname= 'lo_unlink' or proname = 'lo_lseek' or proname = 'lo_tell' or proname = 'loread' or proname = 'lowrite'
ProcessQuery
CommitTransactionCommand
NOTICE: WN: be-fsstubs: lo_commit, isCommit: 1
StartTransactionCommand
NOTICE: WN: xact: StartTransaction
CommitTransactionCommand
NOTICE: WN: be-fsstubs: lo_commit, isCommit: 1
StartTransactionCommand
NOTICE: WN: xact: StartTransaction
NOTICE: LOopen(19425,131072)
NOTICE: WN: be-fsstubs: lo_open: lobjDesc: 821fcd0
NOTICE: WN: be-fsstubs: newLOfd: MAX_LOBJ_FDS: 256, lobjCookie: 821fcd0
NOTICE: WN: be-fsstubs: newLOfd: i: 0, cookies: 0
NOTICE: WN: be-fsstubs: newLOfd: cookie found!
NOTICE: WN: be-fsstubs: newLOfd: cookies[0]=821fcd0
NOTICE: WN: be-fsstubs: lo_open: fd: 0
NOTICE: WN: be-fsstubs: lo_open: return: 0
CommitTransactionCommand
NOTICE: WN: be-fsstubs: lo_commit, isCommit: 1
NOTICE: WN: be-fsstubs: cookies[0]=NULL!
StartTransactionCommand
NOTICE: WN: xact: StartTransaction
NOTICE: WN: be-fsstubs: lo_lseek, fd: 0
NOTICE: WN: be-fsstubs: lo_lseek: cookies[0]=0
ERROR: lo_lseek: invalid large obj descriptor (0)
AbortCurrentTransaction
NOTICE: WN: be-fsstubs: lo_commit, isCommit: 0
proc_exit(0) [#0]
shmem_exit(0) [#0]
NOTICE: WN: xact: StartTransaction
pq_flush: send() failed: Bad file descriptor
NOTICE: WN: be-fsstubs: lo_commit, isCommit: 1
pq_flush: send() failed: Bad file descriptor
exit(0)
/usr/local/postgres/bin/postmaster: reaping dead processes...
/usr/local/postgres/bin/postmaster: CleanupProc: pid 13256 exited with status 0
pmdie 15
proc_exit(0) [#0]
shmem_exit(0) [#0]
exit(0)
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