int
lo_read(int fd, char *buf, int len)
{
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];
/* We don't bother to check IFS_RDLOCK, since it's always set */
/* Permission checks --- first time through only */
if ((lobj->flags & IFS_RD_PERM_OK) == 0)
{
if (!lo_compat_privileges &&
pg_largeobject_aclcheck_snapshot(lobj->id,
GetUserId(),
ACL_SELECT,
lobj->snapshot) != ACLCHECK_OK)
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied for large object %u",
lobj->id)));
lobj->flags |= IFS_RD_PERM_OK;
}
status = inv_read(lobj, buf, len);
return status;
}
int
lo_read(int fd, char *buf, int len)
{
int status;
if (fd < 0 || fd >= cookies_size || cookies[fd] == NULL)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("invalid large-object descriptor: %d", fd)));
/* Permission checks */
if (!lo_compat_privileges &&
pg_largeobject_aclcheck_snapshot(cookies[fd]->id,
GetUserId(),
ACL_SELECT,
cookies[fd]->snapshot) != ACLCHECK_OK)
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied for large object %u",
cookies[fd]->id)));
status = inv_read(cookies[fd], buf, len);
return status;
}
int
lo_read(int fd, char *buf, int len)
{
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;
}
/*
* Read [offset, offset+nbytes) within LO; when nbytes is -1, read to end.
*/
static bytea *
lo_get_fragment_internal(Oid loOid, int64 offset, int32 nbytes)
{
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;
}
int
lo_read(int fd, char *buf, int len)
{
int status;
LargeObjectDesc *lobj;
#ifdef PGXC
#ifdef XCP
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("Postgres-XL does not yet support large objects"),
errdetail("The feature is not currently supported")));
#else
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("Postgres-XC does not support large object yet"),
errdetail("The feature is not currently supported")));
#endif
#endif
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];
/* We don't bother to check IFS_RDLOCK, since it's always set */
/* Permission checks --- first time through only */
if ((lobj->flags & IFS_RD_PERM_OK) == 0)
{
if (!lo_compat_privileges &&
pg_largeobject_aclcheck_snapshot(lobj->id,
GetUserId(),
ACL_SELECT,
lobj->snapshot) != ACLCHECK_OK)
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("permission denied for large object %u",
lobj->id)));
lobj->flags |= IFS_RD_PERM_OK;
}
status = inv_read(lobj, buf, len);
return status;
}
int
lo_read(int fd, char *buf, int len)
{
int status;
if (fd < 0 || fd >= cookies_size || cookies[fd] == NULL)
{
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("invalid large-object descriptor: %d", fd)));
return -1;
}
status = inv_read(cookies[fd], buf, len);
return status;
}
/*
* lo_export -
* exports an (inversion) large object.
*/
Datum
lo_export(PG_FUNCTION_ARGS)
{
Oid lobjId = PG_GETARG_OID(0);
text *filename = PG_GETARG_TEXT_PP(1);
File fd;
int nbytes,
tmp;
char buf[BUFSIZE];
char fnamebuf[MAXPGPATH];
LargeObjectDesc *lobj;
mode_t oumask;
#ifndef ALLOW_DANGEROUS_LO_FUNCTIONS
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser to use server-side lo_export()"),
errhint("Anyone can use the client-side lo_export() provided by libpq.")));
#endif
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);
fd = PathNameOpenFile(fnamebuf, O_CREAT | O_WRONLY | O_TRUNC | PG_BINARY,
S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
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 = FileWrite(fd, buf, nbytes);
if (tmp != nbytes)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not write server file \"%s\": %m",
fnamebuf)));
}
FileClose(fd);
inv_close(lobj);
PG_RETURN_INT32(1);
}
/*
* lo_export -
* exports an (inversion) large object.
*/
Datum
be_lo_export(PG_FUNCTION_ARGS)
{
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);
}
