be-fsstubs.c File Reference

#include "postgres.h"
#include <fcntl.h>
#include <sys/stat.h>
#include <unistd.h>
#include "libpq/be-fsstubs.h"
#include "libpq/libpq-fs.h"
#include "miscadmin.h"
#include "storage/fd.h"
#include "storage/large_object.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/memutils.h"

Include dependency graph for be-fsstubs.c:

Go to the source code of this file.

Macros
#define	BUFSIZE   8192
#define	CreateFSContext()

Functions
static int	newLOfd (LargeObjectDesc *lobjCookie)
static void	deleteLOfd (int fd)
static Oid	lo_import_internal (text *filename, Oid lobjOid)
Datum	be_lo_open (PG_FUNCTION_ARGS)
Datum	be_lo_close (PG_FUNCTION_ARGS)
int	lo_read (int fd, char *buf, int len)
int	lo_write (int fd, const char *buf, int len)
Datum	be_lo_lseek (PG_FUNCTION_ARGS)
Datum	be_lo_lseek64 (PG_FUNCTION_ARGS)
Datum	be_lo_creat (PG_FUNCTION_ARGS)
Datum	be_lo_create (PG_FUNCTION_ARGS)
Datum	be_lo_tell (PG_FUNCTION_ARGS)
Datum	be_lo_tell64 (PG_FUNCTION_ARGS)
Datum	be_lo_unlink (PG_FUNCTION_ARGS)
Datum	be_loread (PG_FUNCTION_ARGS)
Datum	be_lowrite (PG_FUNCTION_ARGS)
Datum	be_lo_import (PG_FUNCTION_ARGS)
Datum	be_lo_import_with_oid (PG_FUNCTION_ARGS)
Datum	be_lo_export (PG_FUNCTION_ARGS)
static void	lo_truncate_internal (int32 fd, int64 len)
Datum	be_lo_truncate (PG_FUNCTION_ARGS)
Datum	be_lo_truncate64 (PG_FUNCTION_ARGS)
void	AtEOXact_LargeObject (bool isCommit)
void	AtEOSubXact_LargeObject (bool isCommit, SubTransactionId mySubid, SubTransactionId parentSubid)
static bytea *	lo_get_fragment_internal (Oid loOid, int64 offset, int32 nbytes)
Datum	be_lo_get (PG_FUNCTION_ARGS)
Datum	be_lo_get_fragment (PG_FUNCTION_ARGS)
Datum	be_lo_from_bytea (PG_FUNCTION_ARGS)
Datum	be_lo_put (PG_FUNCTION_ARGS)

Variables
static LargeObjectDesc **	cookies = NULL
static int	cookies_size = 0
static MemoryContext	fscxt = NULL

Macro Definition Documentation

BUFSIZE

#define BUFSIZE   8192

Definition at line 57 of file be-fsstubs.c.

Referenced by be_lo_export(), and lo_import_internal().

CreateFSContext

#define CreateFSContext

(

)

Value:

do { \
        if (fscxt == NULL) \
            fscxt = AllocSetContextCreate(TopMemoryContext, \
                                          "Filesystem", \
                                          ALLOCSET_DEFAULT_SIZES); \
    } while (0)

Definition at line 72 of file be-fsstubs.c.

Referenced by be_lo_creat(), be_lo_create(), be_lo_export(), be_lo_from_bytea(), be_lo_open(), be_lo_put(), lo_get_fragment_internal(), and lo_import_internal().

Function Documentation

AtEOSubXact_LargeObject()

void AtEOSubXact_LargeObject	(	bool	isCommit,
		SubTransactionId	mySubid,
		SubTransactionId	parentSubid
	)

Definition at line 624 of file be-fsstubs.c.

References cookies_size, deleteLOfd(), i, inv_close(), and LargeObjectDesc::subid.

Referenced by AbortSubTransaction(), and CommitSubTransaction().

{
    int         i;

    if (fscxt == NULL)          /* no LO operations in this xact */
        return;

    for (i = 0; i < cookies_size; i++)
    {
        LargeObjectDesc *lo = cookies[i];

        if (lo != NULL && lo->subid == mySubid)
        {
            if (isCommit)
                lo->subid = parentSubid;
            else
            {
                /*
                 * Make sure we do not call inv_close twice if it errors out
                 * for some reason.  Better a leak than a crash.
                 */
                deleteLOfd(i);
                inv_close(lo);
            }
        }
    }
}

AtEOXact_LargeObject()

void AtEOXact_LargeObject

(

bool

isCommit

)

Definition at line 583 of file be-fsstubs.c.

References close_lo_relation(), cookies_size, deleteLOfd(), i, inv_close(), and MemoryContextDelete().

Referenced by AbortTransaction(), CommitTransaction(), and PrepareTransaction().

{
    int         i;

    if (fscxt == NULL)
        return;                 /* no LO operations in this xact */

    /*
     * Close LO fds and clear cookies array so that LO fds are no longer good.
     * On abort we skip the close step.
     */
    for (i = 0; i < cookies_size; i++)
    {
        if (cookies[i] != NULL)
        {
            if (isCommit)
                inv_close(cookies[i]);
            deleteLOfd(i);
        }
    }

    /* Needn't actually pfree since we're about to zap context */
    cookies = NULL;
    cookies_size = 0;

    /* Release the LO memory context to prevent permanent memory leaks. */
    MemoryContextDelete(fscxt);
    fscxt = NULL;

    /* Give inv_api.c a chance to clean up, too */
    close_lo_relation(isCommit);
}

be_lo_close()

Datum be_lo_close

(

PG_FUNCTION_ARGS

)

Definition at line 112 of file be-fsstubs.c.

References cookies_size, DEBUG4, deleteLOfd(), elog, ereport, errcode(), errmsg(), ERROR, fd(), inv_close(), PG_GETARG_INT32, and PG_RETURN_INT32.

{
    int32       fd = PG_GETARG_INT32(0);

    if (fd < 0 || fd >= cookies_size || cookies[fd] == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_OBJECT),
                 errmsg("invalid large-object descriptor: %d", fd)));

#if FSDB
    elog(DEBUG4, "lo_close(%d)", fd);
#endif

    inv_close(cookies[fd]);

    deleteLOfd(fd);

    PG_RETURN_INT32(0);
}

be_lo_creat()

Datum be_lo_creat

(

PG_FUNCTION_ARGS

)

Definition at line 237 of file be-fsstubs.c.

References CreateFSContext, inv_create(), InvalidOid, and PG_RETURN_OID.

{
    Oid         lobjId;

    /*
     * We don't actually need to store into fscxt, but create it anyway to
     * ensure that AtEOXact_LargeObject knows there is state to clean up
     */
    CreateFSContext();

    lobjId = inv_create(InvalidOid);

    PG_RETURN_OID(lobjId);
}

be_lo_create()

Datum be_lo_create

(

PG_FUNCTION_ARGS

)

Definition at line 253 of file be-fsstubs.c.

References CreateFSContext, inv_create(), PG_GETARG_OID, and PG_RETURN_OID.

{
    Oid         lobjId = PG_GETARG_OID(0);

    /*
     * We don't actually need to store into fscxt, but create it anyway to
     * ensure that AtEOXact_LargeObject knows there is state to clean up
     */
    CreateFSContext();

    lobjId = inv_create(lobjId);

    PG_RETURN_OID(lobjId);
}

be_lo_export()

Datum be_lo_export

(

PG_FUNCTION_ARGS

)

Definition at line 468 of file be-fsstubs.c.

References buf, BUFSIZE, CloseTransientFile(), CreateFSContext, ereport, errcode_for_file_access(), errmsg(), ERROR, fd(), filename, inv_close(), inv_open(), INV_READ, inv_read(), MAXPGPATH, OpenTransientFilePerm(), PG_BINARY, PG_CATCH, PG_END_TRY, PG_GETARG_OID, PG_GETARG_TEXT_PP, PG_RE_THROW, PG_RETURN_INT32, PG_TRY, S_IRGRP, S_IROTH, S_IRUSR, S_IWGRP, S_IWOTH, S_IWUSR, text_to_cstring_buffer(), and write.

{
    Oid         lobjId = PG_GETARG_OID(0);
    text       *filename = PG_GETARG_TEXT_PP(1);
    int         fd;
    int         nbytes,
                tmp;
    char        buf[BUFSIZE];
    char        fnamebuf[MAXPGPATH];
    LargeObjectDesc *lobj;
    mode_t      oumask;

    CreateFSContext();

    /*
     * open the inversion object (no need to test for failure)
     */
    lobj = inv_open(lobjId, INV_READ, fscxt);

    /*
     * 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.
     */
    text_to_cstring_buffer(filename, fnamebuf, sizeof(fnamebuf));
    oumask = umask(S_IWGRP | S_IWOTH);
    PG_TRY();
    {
        fd = OpenTransientFilePerm(fnamebuf, O_CREAT | O_WRONLY | O_TRUNC | PG_BINARY,
                                   S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
    }
    PG_CATCH();
    {
        umask(oumask);
        PG_RE_THROW();
    }
    PG_END_TRY();
    umask(oumask);
    if (fd < 0)
        ereport(ERROR,
                (errcode_for_file_access(),
                 errmsg("could not create server file \"%s\": %m",
                        fnamebuf)));

    /*
     * read in from the inversion file and write to the filesystem
     */
    while ((nbytes = inv_read(lobj, buf, BUFSIZE)) > 0)
    {
        tmp = write(fd, buf, nbytes);
        if (tmp != nbytes)
            ereport(ERROR,
                    (errcode_for_file_access(),
                     errmsg("could not write server file \"%s\": %m",
                            fnamebuf)));
    }

    CloseTransientFile(fd);
    inv_close(lobj);

    PG_RETURN_INT32(1);
}

be_lo_from_bytea()

Datum be_lo_from_bytea

(

PG_FUNCTION_ARGS

)

Definition at line 805 of file be-fsstubs.c.

References Assert, CreateFSContext, inv_close(), inv_create(), inv_open(), INV_WRITE, inv_write(), PG_GETARG_BYTEA_PP, PG_GETARG_OID, PG_RETURN_OID, PG_USED_FOR_ASSERTS_ONLY, generate_unaccent_rules::str, VARDATA_ANY, and VARSIZE_ANY_EXHDR.

{
    Oid         loOid = PG_GETARG_OID(0);
    bytea      *str = PG_GETARG_BYTEA_PP(1);
    LargeObjectDesc *loDesc;
    int         written PG_USED_FOR_ASSERTS_ONLY;

    CreateFSContext();

    loOid = inv_create(loOid);
    loDesc = inv_open(loOid, INV_WRITE, fscxt);
    written = inv_write(loDesc, VARDATA_ANY(str), VARSIZE_ANY_EXHDR(str));
    Assert(written == VARSIZE_ANY_EXHDR(str));
    inv_close(loDesc);

    PG_RETURN_OID(loOid);
}

be_lo_get()

Datum be_lo_get

(

PG_FUNCTION_ARGS

)

Definition at line 770 of file be-fsstubs.c.

References lo_get_fragment_internal(), PG_GETARG_OID, and PG_RETURN_BYTEA_P.

{
    Oid         loOid = PG_GETARG_OID(0);
    bytea      *result;

    result = lo_get_fragment_internal(loOid, 0, -1);

    PG_RETURN_BYTEA_P(result);
}

be_lo_get_fragment()

Datum be_lo_get_fragment

(

PG_FUNCTION_ARGS

)

Definition at line 784 of file be-fsstubs.c.

References ereport, errcode(), errmsg(), ERROR, lo_get_fragment_internal(), PG_GETARG_INT32, PG_GETARG_INT64, PG_GETARG_OID, and PG_RETURN_BYTEA_P.

{
    Oid         loOid = PG_GETARG_OID(0);
    int64       offset = PG_GETARG_INT64(1);
    int32       nbytes = PG_GETARG_INT32(2);
    bytea      *result;

    if (nbytes < 0)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                 errmsg("requested length cannot be negative")));

    result = lo_get_fragment_internal(loOid, offset, nbytes);

    PG_RETURN_BYTEA_P(result);
}

be_lo_import()

Datum be_lo_import

(

PG_FUNCTION_ARGS

)

Definition at line 391 of file be-fsstubs.c.

References filename, InvalidOid, lo_import_internal(), PG_GETARG_TEXT_PP, and PG_RETURN_OID.

{
    text       *filename = PG_GETARG_TEXT_PP(0);

    PG_RETURN_OID(lo_import_internal(filename, InvalidOid));
}

be_lo_import_with_oid()

Datum be_lo_import_with_oid

(

PG_FUNCTION_ARGS

)

Definition at line 403 of file be-fsstubs.c.

References filename, lo_import_internal(), PG_GETARG_OID, PG_GETARG_TEXT_PP, and PG_RETURN_OID.

{
    text       *filename = PG_GETARG_TEXT_PP(0);
    Oid         oid = PG_GETARG_OID(1);

    PG_RETURN_OID(lo_import_internal(filename, oid));
}

be_lo_lseek()

Datum be_lo_lseek

(

PG_FUNCTION_ARGS

)

Definition at line 194 of file be-fsstubs.c.

References cookies_size, ereport, errcode(), errmsg(), ERROR, fd(), inv_seek(), PG_GETARG_INT32, PG_RETURN_INT32, and status().

{
    int32       fd = PG_GETARG_INT32(0);
    int32       offset = PG_GETARG_INT32(1);
    int32       whence = PG_GETARG_INT32(2);
    int64       status;

    if (fd < 0 || fd >= cookies_size || cookies[fd] == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_OBJECT),
                 errmsg("invalid large-object descriptor: %d", fd)));

    status = inv_seek(cookies[fd], offset, whence);

    /* guard against result overflow */
    if (status != (int32) status)
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("lo_lseek result out of range for large-object descriptor %d",
                        fd)));

    PG_RETURN_INT32((int32) status);
}

be_lo_lseek64()

Datum be_lo_lseek64

(

PG_FUNCTION_ARGS

)

Definition at line 219 of file be-fsstubs.c.

References cookies_size, ereport, errcode(), errmsg(), ERROR, fd(), inv_seek(), PG_GETARG_INT32, PG_GETARG_INT64, PG_RETURN_INT64, and status().

{
    int32       fd = PG_GETARG_INT32(0);
    int64       offset = PG_GETARG_INT64(1);
    int32       whence = PG_GETARG_INT32(2);
    int64       status;

    if (fd < 0 || fd >= cookies_size || cookies[fd] == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_OBJECT),
                 errmsg("invalid large-object descriptor: %d", fd)));

    status = inv_seek(cookies[fd], offset, whence);

    PG_RETURN_INT64(status);
}

be_lo_open()

Datum be_lo_open

(

PG_FUNCTION_ARGS

)

Definition at line 91 of file be-fsstubs.c.

References CreateFSContext, DEBUG4, elog, fd(), inv_open(), newLOfd(), PG_GETARG_INT32, PG_GETARG_OID, and PG_RETURN_INT32.

{
    Oid         lobjId = PG_GETARG_OID(0);
    int32       mode = PG_GETARG_INT32(1);
    LargeObjectDesc *lobjDesc;
    int         fd;

#if FSDB
    elog(DEBUG4, "lo_open(%u,%d)", lobjId, mode);
#endif

    CreateFSContext();

    lobjDesc = inv_open(lobjId, mode, fscxt);

    fd = newLOfd(lobjDesc);

    PG_RETURN_INT32(fd);
}

be_lo_put()

Datum be_lo_put

(

PG_FUNCTION_ARGS

)

Definition at line 827 of file be-fsstubs.c.

References ACL_UPDATE, ACLCHECK_OK, Assert, CreateFSContext, ereport, errcode(), errmsg(), ERROR, GetUserId(), LargeObjectDesc::id, inv_close(), inv_open(), inv_seek(), INV_WRITE, inv_write(), lo_compat_privileges, PG_GETARG_BYTEA_PP, PG_GETARG_INT64, PG_GETARG_OID, pg_largeobject_aclcheck_snapshot(), PG_RETURN_VOID, PG_USED_FOR_ASSERTS_ONLY, LargeObjectDesc::snapshot, generate_unaccent_rules::str, VARDATA_ANY, and VARSIZE_ANY_EXHDR.

{
    Oid         loOid = PG_GETARG_OID(0);
    int64       offset = PG_GETARG_INT64(1);
    bytea      *str = PG_GETARG_BYTEA_PP(2);
    LargeObjectDesc *loDesc;
    int         written PG_USED_FOR_ASSERTS_ONLY;

    CreateFSContext();

    loDesc = inv_open(loOid, INV_WRITE, fscxt);

    /* Permission check */
    if (!lo_compat_privileges &&
        pg_largeobject_aclcheck_snapshot(loDesc->id,
                                         GetUserId(),
                                         ACL_UPDATE,
                                         loDesc->snapshot) != ACLCHECK_OK)
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                 errmsg("permission denied for large object %u",
                        loDesc->id)));

    inv_seek(loDesc, offset, SEEK_SET);
    written = inv_write(loDesc, VARDATA_ANY(str), VARSIZE_ANY_EXHDR(str));
    Assert(written == VARSIZE_ANY_EXHDR(str));
    inv_close(loDesc);

    PG_RETURN_VOID();
}

be_lo_tell()

Datum be_lo_tell

(

PG_FUNCTION_ARGS

)

Definition at line 269 of file be-fsstubs.c.

References cookies_size, ereport, errcode(), errmsg(), ERROR, fd(), inv_tell(), PG_GETARG_INT32, and PG_RETURN_INT32.

{
    int32       fd = PG_GETARG_INT32(0);
    int64       offset;

    if (fd < 0 || fd >= cookies_size || cookies[fd] == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_OBJECT),
                 errmsg("invalid large-object descriptor: %d", fd)));

    offset = inv_tell(cookies[fd]);

    /* guard against result overflow */
    if (offset != (int32) offset)
        ereport(ERROR,
                (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
                 errmsg("lo_tell result out of range for large-object descriptor %d",
                        fd)));

    PG_RETURN_INT32((int32) offset);
}

be_lo_tell64()

Datum be_lo_tell64

(

PG_FUNCTION_ARGS

)

Definition at line 292 of file be-fsstubs.c.

References cookies_size, ereport, errcode(), errmsg(), ERROR, fd(), inv_tell(), PG_GETARG_INT32, and PG_RETURN_INT64.

{
    int32       fd = PG_GETARG_INT32(0);
    int64       offset;

    if (fd < 0 || fd >= cookies_size || cookies[fd] == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_OBJECT),
                 errmsg("invalid large-object descriptor: %d", fd)));

    offset = inv_tell(cookies[fd]);

    PG_RETURN_INT64(offset);
}

be_lo_truncate()

Datum be_lo_truncate

(

PG_FUNCTION_ARGS

)

Definition at line 559 of file be-fsstubs.c.

References fd(), lo_truncate_internal(), PG_GETARG_INT32, and PG_RETURN_INT32.

{
    int32       fd = PG_GETARG_INT32(0);
    int32       len = PG_GETARG_INT32(1);

    lo_truncate_internal(fd, len);
    PG_RETURN_INT32(0);
}

be_lo_truncate64()

Datum be_lo_truncate64

(

PG_FUNCTION_ARGS

)

Definition at line 569 of file be-fsstubs.c.

References fd(), lo_truncate_internal(), PG_GETARG_INT32, PG_GETARG_INT64, and PG_RETURN_INT32.

{
    int32       fd = PG_GETARG_INT32(0);
    int64       len = PG_GETARG_INT64(1);

    lo_truncate_internal(fd, len);
    PG_RETURN_INT32(0);
}

be_lo_unlink()

Datum be_lo_unlink

(

PG_FUNCTION_ARGS

)

Definition at line 308 of file be-fsstubs.c.

References cookies_size, deleteLOfd(), ereport, errcode(), errmsg(), ERROR, GetUserId(), i, inv_close(), inv_drop(), lo_compat_privileges, PG_GETARG_OID, pg_largeobject_ownercheck(), and PG_RETURN_INT32.

Referenced by lo_manage().

{
    Oid         lobjId = PG_GETARG_OID(0);

    /*
     * Must be owner of the large object.  It would be cleaner to check this
     * in inv_drop(), but we want to throw the error before not after closing
     * relevant FDs.
     */
    if (!lo_compat_privileges &&
        !pg_largeobject_ownercheck(lobjId, GetUserId()))
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                 errmsg("must be owner of large object %u", lobjId)));

    /*
     * If there are any open LO FDs referencing that ID, close 'em.
     */
    if (fscxt != NULL)
    {
        int         i;

        for (i = 0; i < cookies_size; i++)
        {
            if (cookies[i] != NULL && cookies[i]->id == lobjId)
            {
                inv_close(cookies[i]);
                deleteLOfd(i);
            }
        }
    }

    /*
     * inv_drop does not create a need for end-of-transaction cleanup and
     * hence we don't need to have created fscxt.
     */
    PG_RETURN_INT32(inv_drop(lobjId));
}

be_loread()

Datum be_loread

(

PG_FUNCTION_ARGS

)

Definition at line 352 of file be-fsstubs.c.

References fd(), lo_read(), palloc(), PG_GETARG_INT32, PG_RETURN_BYTEA_P, SET_VARSIZE, VARDATA, and VARHDRSZ.

{
    int32       fd = PG_GETARG_INT32(0);
    int32       len = PG_GETARG_INT32(1);
    bytea      *retval;
    int         totalread;

    if (len < 0)
        len = 0;

    retval = (bytea *) palloc(VARHDRSZ + len);
    totalread = lo_read(fd, VARDATA(retval), len);
    SET_VARSIZE(retval, totalread + VARHDRSZ);

    PG_RETURN_BYTEA_P(retval);
}

be_lowrite()

Datum be_lowrite

(

PG_FUNCTION_ARGS

)

Definition at line 370 of file be-fsstubs.c.

References fd(), lo_write(), PG_GETARG_BYTEA_PP, PG_GETARG_INT32, PG_RETURN_INT32, VARDATA_ANY, and VARSIZE_ANY_EXHDR.

{
    int32       fd = PG_GETARG_INT32(0);
    bytea      *wbuf = PG_GETARG_BYTEA_PP(1);
    int         bytestowrite;
    int         totalwritten;

    bytestowrite = VARSIZE_ANY_EXHDR(wbuf);
    totalwritten = lo_write(fd, VARDATA_ANY(wbuf), bytestowrite);
    PG_RETURN_INT32(totalwritten);
}

deleteLOfd()

static void deleteLOfd ( int  fd )

static

Definition at line 701 of file be-fsstubs.c.

References fd().

Referenced by AtEOSubXact_LargeObject(), AtEOXact_LargeObject(), be_lo_close(), and be_lo_unlink().

{
    cookies[fd] = NULL;
}

lo_get_fragment_internal()

static bytea* lo_get_fragment_internal ( Oid  loOid, int64  offset, int32  nbytes  )

static

Definition at line 714 of file be-fsstubs.c.

References Assert, CreateFSContext, ereport, errcode(), errmsg(), ERROR, inv_close(), inv_open(), INV_READ, inv_read(), inv_seek(), MaxAllocSize, palloc(), PG_USED_FOR_ASSERTS_ONLY, SET_VARSIZE, VARDATA, and VARHDRSZ.

Referenced by be_lo_get(), and be_lo_get_fragment().

{
    LargeObjectDesc *loDesc;
    int64       loSize;
    int64       result_length;
    int         total_read PG_USED_FOR_ASSERTS_ONLY;
    bytea      *result = NULL;

    /*
     * We don't actually need to store into fscxt, but create it anyway to
     * ensure that AtEOXact_LargeObject knows there is state to clean up
     */
    CreateFSContext();

    loDesc = inv_open(loOid, INV_READ, fscxt);

    /*
     * Compute number of bytes we'll actually read, accommodating nbytes == -1
     * and reads beyond the end of the LO.
     */
    loSize = inv_seek(loDesc, 0, SEEK_END);
    if (loSize > offset)
    {
        if (nbytes >= 0 && nbytes <= loSize - offset)
            result_length = nbytes; /* request is wholly inside LO */
        else
            result_length = loSize - offset;    /* adjust to end of LO */
    }
    else
        result_length = 0;      /* request is wholly outside LO */

    /*
     * A result_length calculated from loSize may not fit in a size_t.  Check
     * that the size will satisfy this and subsequently-enforced size limits.
     */
    if (result_length > MaxAllocSize - VARHDRSZ)
        ereport(ERROR,
                (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
                 errmsg("large object read request is too large")));

    result = (bytea *) palloc(VARHDRSZ + result_length);

    inv_seek(loDesc, offset, SEEK_SET);
    total_read = inv_read(loDesc, VARDATA(result), result_length);
    Assert(total_read == result_length);
    SET_VARSIZE(result, result_length + VARHDRSZ);

    inv_close(loDesc);

    return result;
}

lo_import_internal()

static Oid lo_import_internal ( text *  filename, Oid  lobjOid  )

static

Definition at line 412 of file be-fsstubs.c.

References Assert, buf, BUFSIZE, CloseTransientFile(), CreateFSContext, ereport, errcode_for_file_access(), errmsg(), ERROR, fd(), inv_close(), inv_create(), inv_open(), INV_WRITE, inv_write(), MAXPGPATH, OpenTransientFile(), PG_BINARY, PG_USED_FOR_ASSERTS_ONLY, read, and text_to_cstring_buffer().

Referenced by be_lo_import(), and be_lo_import_with_oid().

{
    int         fd;
    int         nbytes,
                tmp PG_USED_FOR_ASSERTS_ONLY;
    char        buf[BUFSIZE];
    char        fnamebuf[MAXPGPATH];
    LargeObjectDesc *lobj;
    Oid         oid;

    CreateFSContext();

    /*
     * open the file to be read in
     */
    text_to_cstring_buffer(filename, fnamebuf, sizeof(fnamebuf));
    fd = OpenTransientFile(fnamebuf, O_RDONLY | PG_BINARY);
    if (fd < 0)
        ereport(ERROR,
                (errcode_for_file_access(),
                 errmsg("could not open server file \"%s\": %m",
                        fnamebuf)));

    /*
     * create an inversion object
     */
    oid = inv_create(lobjOid);

    /*
     * read in from the filesystem and write to the inversion object
     */
    lobj = inv_open(oid, INV_WRITE, fscxt);

    while ((nbytes = read(fd, buf, BUFSIZE)) > 0)
    {
        tmp = inv_write(lobj, buf, nbytes);
        Assert(tmp == nbytes);
    }

    if (nbytes < 0)
        ereport(ERROR,
                (errcode_for_file_access(),
                 errmsg("could not read server file \"%s\": %m",
                        fnamebuf)));

    inv_close(lobj);
    CloseTransientFile(fd);

    return oid;
}

lo_read()

int lo_read	(	int	fd,
		char *	buf,
		int	len
	)

Definition at line 142 of file be-fsstubs.c.

References cookies_size, ereport, errcode(), errmsg(), ERROR, fd(), LargeObjectDesc::flags, IFS_RDLOCK, inv_read(), and status().

Referenced by be_loread(), dumpBlobs(), exportFile(), and pickout().

{
    int         status;
    LargeObjectDesc *lobj;

    if (fd < 0 || fd >= cookies_size || cookies[fd] == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_OBJECT),
                 errmsg("invalid large-object descriptor: %d", fd)));
    lobj = cookies[fd];

    /*
     * Check state.  inv_read() would throw an error anyway, but we want the
     * error to be about the FD's state not the underlying privilege; it might
     * be that the privilege exists but user forgot to ask for read mode.
     */
    if ((lobj->flags & IFS_RDLOCK) == 0)
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("large object descriptor %d was not opened for reading",
                        fd)));

    status = inv_read(lobj, buf, len);

    return status;
}

lo_truncate_internal()

static void lo_truncate_internal ( int32  fd, int64  len  )

static

Definition at line 538 of file be-fsstubs.c.

References cookies_size, ereport, errcode(), errmsg(), ERROR, fd(), LargeObjectDesc::flags, IFS_WRLOCK, and inv_truncate().

Referenced by be_lo_truncate(), and be_lo_truncate64().

{
    LargeObjectDesc *lobj;

    if (fd < 0 || fd >= cookies_size || cookies[fd] == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_OBJECT),
                 errmsg("invalid large-object descriptor: %d", fd)));
    lobj = cookies[fd];

    /* see comment in lo_read() */
    if ((lobj->flags & IFS_WRLOCK) == 0)
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("large object descriptor %d was not opened for writing",
                        fd)));

    inv_truncate(lobj, len);
}

lo_write()

int lo_write	(	int	fd,
		const char *	buf,
		int	len
	)

Definition at line 170 of file be-fsstubs.c.

References cookies_size, ereport, errcode(), errmsg(), ERROR, fd(), LargeObjectDesc::flags, IFS_WRLOCK, inv_write(), and status().

Referenced by be_lowrite(), dump_lo_buf(), importFile(), and overwrite().

{
    int         status;
    LargeObjectDesc *lobj;

    if (fd < 0 || fd >= cookies_size || cookies[fd] == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_OBJECT),
                 errmsg("invalid large-object descriptor: %d", fd)));
    lobj = cookies[fd];

    /* see comment in lo_read() */
    if ((lobj->flags & IFS_WRLOCK) == 0)
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("large object descriptor %d was not opened for writing",
                        fd)));

    status = inv_write(lobj, buf, len);

    return status;
}

newLOfd()

static int newLOfd ( LargeObjectDesc *  lobjCookie )

static

Definition at line 658 of file be-fsstubs.c.

References Assert, cookies_size, i, MemoryContextAllocZero(), MemSet, and repalloc().

Referenced by be_lo_open().

{
    int         i,
                newsize;

    /* Try to find a free slot */
    for (i = 0; i < cookies_size; i++)
    {
        if (cookies[i] == NULL)
        {
            cookies[i] = lobjCookie;
            return i;
        }
    }

    /* No free slot, so make the array bigger */
    if (cookies_size <= 0)
    {
        /* First time through, arbitrarily make 64-element array */
        i = 0;
        newsize = 64;
        cookies = (LargeObjectDesc **)
            MemoryContextAllocZero(fscxt, newsize * sizeof(LargeObjectDesc *));
        cookies_size = newsize;
    }
    else
    {
        /* Double size of array */
        i = cookies_size;
        newsize = cookies_size * 2;
        cookies = (LargeObjectDesc **)
            repalloc(cookies, newsize * sizeof(LargeObjectDesc *));
        MemSet(cookies + cookies_size, 0,
               (newsize - cookies_size) * sizeof(LargeObjectDesc *));
        cookies_size = newsize;
    }

    Assert(cookies[i] == NULL);
    cookies[i] = lobjCookie;
    return i;
}

Variable Documentation

cookies

LargeObjectDesc** cookies = NULL

static

Definition at line 67 of file be-fsstubs.c.

cookies_size

int cookies_size = 0

static

Definition at line 68 of file be-fsstubs.c.

Referenced by AtEOSubXact_LargeObject(), AtEOXact_LargeObject(), be_lo_close(), be_lo_lseek(), be_lo_lseek64(), be_lo_tell(), be_lo_tell64(), be_lo_unlink(), lo_read(), lo_truncate_internal(), lo_write(), and newLOfd().

fscxt

MemoryContext fscxt = NULL

static

Definition at line 70 of file be-fsstubs.c.