int
_tmf_bksp(struct fdinfo *fio, struct ffsw *stat)
{
struct tmfio *xf_info;
register int ret;
int usertm;
xf_info = (struct tmfio *)fio->lyr_info;
if (xf_info->tmf_tpos) {
if (_tmf_tpwait (xf_info) < 0) {
ERETURN(stat, errno, 0);
}
}
/*
* If the file's been writing, flush out any unwritten data.
*/
if (xf_info->rwflag == WRITIN) {
if (_tmf_flush(fio, stat) < 0) {
return(ERR);
}
}
/*
* Now backspace.
*/
ret = _tmf_stpos(fio, FP_TPOS_BACK, 1, 0, 0, 0, &usertm, stat);
if (ret < 0 && stat->sw_error != ETBOF)
return(ERR);
xf_info->rwflag = POSITIN;
return(0);
}
/*
* Skip file.
* Note that this has slightly different meaning that skip tape mark.
* Except in the case where you request positioning past EOD,
* _tmp_skipf will position you at the beginning of a file. That is,
* _tmf_skipf will position you either at BOD, immediately after a
* user tape mark, or at EOD.
*/
int
_tmf_skipf(
struct fdinfo *fio,
long nb,
int *count,
struct ffsw *stat)
{
int rescnt;
int usertm;
struct tmfio *xf_info;
xf_info = (struct tmfio *)fio->lyr_info;
*count = 0;
if (nb == 0) {
/* Position to 0. This will cause us to wait for */
/* any outstanding positioning, to flush any unwritten data, */
/* and if we're ever doing */
/* read-ahead it will clear that out. */
if (_tmf_stpos(fio, FP_TPOS_BACK, 0, 0, 0, 0, &usertm, stat) < 0) {
return(ERR);
}
return(0);
}
else if (nb > 0) {
/* Positioning forward nb files.*/
/* First position to 0. This will cause us to wait for */
/* any outstanding positioning, to flush any unwritten data, */
/* and if we're ever doing read-ahead it will */
/* clear that out. */
if (_tmf_stpos(fio, FP_TPOS_BACK, 0, 0, 0, 0, &usertm, stat) < 0) {
return(ERR);
}
if (xf_info->tmf_rwtpmk == 0) {
/* No user tape marks */
ERETURN(stat, FETASKPF, 0);
}
if (_tmf_skiptpmk(xf_info->tmf_fd, nb, &rescnt, stat) < 0) {
if (stat->sw_error != ETEOF) {
return(ERR);
}
}
*count = nb - rescnt;
}
else {
/* Positioning back nb files */
/* First position back 1 record. If we were */
/* immediately after a tapemark, then this */
/* will put us in the previous file. */
if (_tmf_stpos(fio, FP_TPOS_BACK, 1, 0, 0, 0, &usertm, stat) < 0) {
if (stat->sw_error == ETBOF) {
return(0);
}
return(ERR);
}
if (xf_info->tmf_rwtpmk == 0) {
/* No user tape marks, just rewind */
if (_tmf_seek(fio,0,0,stat) < 0) {
*count = -nb;
return(ERR);
}
*count = 0;
return(0);
}
/* Now position back nb files */
if (_tmf_skiptpmk(xf_info->tmf_fd, nb, &rescnt, stat) == 0) {
/* Move to the other side of this tape mark */
int ut;
if (_tmf_stpos(fio, FP_TPOS_FORW, 1, 0, 0, 0, &ut, stat) < 0) {
return(ERR);
}
}
else {
if (stat->sw_error != ETBOF) {
return(ERR);
}
}
*count = -nb - rescnt;
if (usertm == 0) {
/* The user was positioned in the middle of a file. */
if (*count > 0)
*count = *count - 1;
}
}
return(0);
}
