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postgresql/src/interfaces/libpq/fe-lobj.c

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/*-------------------------------------------------------------------------
*
* fe-lobj.c
* Front-end large object interface
*
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-lobj.c,v 1.30 2000/06/02 15:57:42 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include <fcntl.h>
#include <sys/stat.h>
#include "postgres.h"
#include "libpq-fe.h"
#include "libpq-int.h"
#ifdef WIN32
#include "win32.h"
#include "io.h"
#else
#include <unistd.h>
#endif
#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;
if (conn->lobjfuncs == (PGlobjfuncs *) NULL)
{
if (lo_initialize(conn) < 0)
return -1;
}
res = PQfn(conn, conn->lobjfuncs->fn_lo_open, &fd, &result_len, 1, argv, 2);
if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
PQclear(res);
/* have to do this to reset offset in shared fd cache */
/* but only if fd is valid */
if (fd >= 0 && lo_lseek(conn, fd, 0L, SEEK_SET) < 0)
return -1;
return fd;
}
else
{
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, size_t 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, size_t 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, const char *filename)
{
int fd;
int nbytes,
tmp;
char buf[LO_BUFSIZE];
Oid lobjOid;
int lobj;
/*
* open the file to be read in
*/
fd = open(filename, O_RDONLY | PG_BINARY, 0666);
if (fd < 0)
{ /* error */
printfPQExpBuffer(&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)
{
printfPQExpBuffer(&conn->errorMessage,
"lo_import: can't create inv object for \"%s\"",
filename);
return InvalidOid;
}
lobj = lo_open(conn, lobjOid, INV_WRITE);
if (lobj == -1)
{
printfPQExpBuffer(&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)
{
printfPQExpBuffer(&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, const 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)
{
printfPQExpBuffer(&conn->errorMessage,
"lo_export: can't open inv object %u", lobjId);
return -1;
}
/*
* open the file to be written to
*/
fd = open(filename, O_CREAT | O_WRONLY | O_TRUNC | PG_BINARY, 0666);
if (fd < 0)
{ /* error */
printfPQExpBuffer(&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)
{
printfPQExpBuffer(&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;
const char *fname;
Oid foid;
/* ----------------
* Allocate the structure to hold the functions OID's
* ----------------
*/
lobjfuncs = (PGlobjfuncs *) malloc(sizeof(PGlobjfuncs));
if (lobjfuncs == (PGlobjfuncs *) NULL)
{
printfPQExpBuffer(&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);
printfPQExpBuffer(&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)
{
printfPQExpBuffer(&conn->errorMessage,
"ERROR: Cannot determine OID for function lo_open\n");
free(lobjfuncs);
return -1;
}
if (lobjfuncs->fn_lo_close == 0)
{
printfPQExpBuffer(&conn->errorMessage,
"ERROR: Cannot determine OID for function lo_close\n");
free(lobjfuncs);
return -1;
}
if (lobjfuncs->fn_lo_creat == 0)
{
printfPQExpBuffer(&conn->errorMessage,
"ERROR: Cannot determine OID for function lo_creat\n");
free(lobjfuncs);
return -1;
}
if (lobjfuncs->fn_lo_unlink == 0)
{
printfPQExpBuffer(&conn->errorMessage,
"ERROR: Cannot determine OID for function lo_unlink\n");
free(lobjfuncs);
return -1;
}
if (lobjfuncs->fn_lo_lseek == 0)
{
printfPQExpBuffer(&conn->errorMessage,
"ERROR: Cannot determine OID for function lo_lseek\n");
free(lobjfuncs);
return -1;
}
if (lobjfuncs->fn_lo_tell == 0)
{
printfPQExpBuffer(&conn->errorMessage,
"ERROR: Cannot determine OID for function lo_tell\n");
free(lobjfuncs);
return -1;
}
if (lobjfuncs->fn_lo_read == 0)
{
printfPQExpBuffer(&conn->errorMessage,
"ERROR: Cannot determine OID for function loread\n");
free(lobjfuncs);
return -1;
}
if (lobjfuncs->fn_lo_write == 0)
{
printfPQExpBuffer(&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;
}
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