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/*
* I use these routines just to decide when I have to fake a
* volume-table to preserve compatability to original ftape.
*/
/*
* Copyright (C) 1994-1995 Bas Laarhoven.
*
* Modified for zftape 1996, 1997 Claus Heine.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
* $Source: /homes/cvs/ftape-stacked/ftape/zftape/zftape-eof.c,v $
* $Revision: 1.2 $
* $Date: 1997/10/05 19:19:02 $
*
* This file contains the eof mark handling code
* for the QIC-40/80 floppy-tape driver for Linux.
*/
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/zftape.h>
#include "../zftape/zftape-init.h"
#include "../zftape/zftape-rw.h"
#include "../zftape/zftape-eof.h"
/* Global vars.
*/
/* a copy of the failed sector log from the header segment.
*/
eof_mark_union *zft_eof_map;
/* number of eof marks (entries in bad sector log) on tape.
*/
int zft_nr_eof_marks = -1;
/* Local vars.
*/
static char linux_tape_label[] = "Linux raw format V";
enum {
min_fmt_version = 1, max_fmt_version = 2
};
static unsigned ftape_fmt_version = 0;
/* Ftape (mis)uses the bad sector log to record end-of-file marks.
* Initially (when the tape is erased) all entries in the bad sector
* log are added to the tape's bad sector map. The bad sector log then
* is cleared.
*
* The bad sector log normally contains entries of the form:
* even 16-bit word: segment number of bad sector
* odd 16-bit word: encoded date
* There can be a total of 448 entries (1792 bytes).
*
* My guess is that no program is using this bad sector log (the *
* format seems useless as there is no indication of the bad sector
* itself, only the segment) However, if any program does use the bad
* sector log, the format used by ftape will let the program think
* there are some bad sectors and no harm is done.
*
* The eof mark entries that ftape stores in the bad sector log: even
* 16-bit word: segment number of eof mark odd 16-bit word: sector
* number of eof mark [1..32]
*
* The zft_eof_map as maintained is a sorted list of eof mark entries.
*
*
* The tape name field in the header segments is used to store a linux
* tape identification string and a version number. This way the tape
* can be recognized as a Linux raw format tape when using tools under
* other OS's.
*
* 'Wide' QIC tapes (format code 4) don't have a failed sector list
* anymore. That space is used for the (longer) bad sector map that
* now is a variable length list too. We now store our end-of-file
* marker list after the bad-sector-map on tape. The list is delimited
* by a (__u32) 0 entry.
*/
int zft_ftape_validate_label(char *label)
{
static char tmp_label[45];
int result = 0;
TRACE_FUN(ft_t_any);
memcpy(tmp_label, label, FT_LABEL_SZ);
tmp_label[FT_LABEL_SZ] = '\0';
TRACE(ft_t_noise, "tape label = `%s'", tmp_label);
ftape_fmt_version = 0;
if (memcmp(label, linux_tape_label, strlen(linux_tape_label)) == 0) {
int pos = strlen(linux_tape_label);
while (label[pos] >= '0' && label[pos] <= '9') {
ftape_fmt_version *= 10;
ftape_fmt_version = label[ pos++] - '0';
}
result = (ftape_fmt_version >= min_fmt_version &&
ftape_fmt_version <= max_fmt_version);
}
TRACE(ft_t_noise, "format version = %d", ftape_fmt_version);
TRACE_EXIT result;
}
static __u8 * find_end_of_eof_list(__u8 * ptr, __u8 * limit)
{
while (ptr + 3 < limit) {
if (get_unaligned((__u32*)ptr)) {
++(__u32*)ptr;
} else {
return ptr;
}
}
return NULL;
}
void zft_ftape_extract_file_marks(__u8* address)
{
int i;
TRACE_FUN(ft_t_any);
zft_eof_map = NULL;
if (ft_format_code == fmt_var || ft_format_code == fmt_big) {
__u8* end;
__u8* start = ftape_find_end_of_bsm_list(address);
zft_nr_eof_marks = 0;
if (start) {
start += 3; /* skip end of list mark */
end = find_end_of_eof_list(start,
address + FT_SEGMENT_SIZE);
if (end && end - start <= FT_FSL_SIZE) {
zft_nr_eof_marks = ((end - start) /
sizeof(eof_mark_union));
zft_eof_map = (eof_mark_union *)start;
} else {
TRACE(ft_t_err,
"EOF Mark List is too long or damaged!");
}
} else {
TRACE(ft_t_err,
"Bad Sector List is too long or damaged !");
}
} else {
zft_eof_map = (eof_mark_union *)&address[FT_FSL];
zft_nr_eof_marks = GET2(address, FT_FSL_CNT);
}
TRACE(ft_t_noise, "number of file marks: %d", zft_nr_eof_marks);
if (ftape_fmt_version == 1) {
TRACE(ft_t_info, "swapping version 1 fields");
/* version 1 format uses swapped sector and segment
* fields, correct that !
*/
for (i = 0; i < zft_nr_eof_marks; ++i) {
__u16 tmp = GET2(&zft_eof_map[i].mark.segment,0);
PUT2(&zft_eof_map[i].mark.segment, 0,
GET2(&zft_eof_map[i].mark.date,0));
PUT2(&zft_eof_map[i].mark.date, 0, tmp);
}
}
for (i = 0; i < zft_nr_eof_marks; ++i) {
TRACE(ft_t_noise, "eof mark: %5d/%2d",
GET2(&zft_eof_map[i].mark.segment, 0),
GET2(&zft_eof_map[i].mark.date,0));
}
TRACE_EXIT;
}
void zft_clear_ftape_file_marks(void)
{
TRACE_FUN(ft_t_flow);
/* Clear failed sector log: remove all tape marks. We
* don't use old ftape-style EOF-marks.
*/
TRACE(ft_t_info, "Clearing old ftape's eof map");
memset(zft_eof_map, 0, zft_nr_eof_marks * sizeof(__u32));
zft_nr_eof_marks = 0;
PUT2(zft_hseg_buf, FT_FSL_CNT, 0); /* nr of eof-marks */
zft_header_changed = 1;
zft_update_label(zft_hseg_buf);
TRACE_EXIT;
}
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