* Copyright (c) 1996

/* $NetBSD: dosfile.c,v 1.2 2024/06/29 13:46:40 rin Exp $ */

/*
* Copyright (c) 1996
* Matthias Drochner. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/

/*
* DOS filesystem for libsa
* standalone - uses no device, works only with DOS running
* needs lowlevel parts from dos_file.S
*/

#include <lib/libsa/stand.h>

#include "diskbuf.h"
#include "dosfile.h"

struct dosfile {
int doshandle, off;
};

extern int doserrno; /* in dos_file.S */

static int dos2errno(void);

static int
dos2errno(void)
{
int err;

switch (doserrno) {
case 1: /* invalid function number */
case 4: /* too many open files */
case 12: /* invalid access mode */
default:
err = EIO;
break;
case 2: /* file not found */
case 3: /* path not found */
err = ENOENT;
break;
case 5: /* access denied */
err = EPERM;
break;
case 6: /* invalid handle */
err = EINVAL;
break;
}
return err;
}

__compactcall int
dos_open(const char *path, struct open_file *f)
{
struct dosfile *df;

df = (struct dosfile *) alloc(sizeof(*df));
if (!df)
return -1;

df->off = 0;
df->doshandle = dosopen(path);
if (df->doshandle < 0) {
#ifdef DEBUG
printf("DOS error %d\n", doserrno);
#endif
dealloc(df, sizeof(*df));
return dos2errno();
}
f->f_fsdata = (void *) df;
return 0;
}

__compactcall int
dos_read(struct open_file *f, void *addr, size_t size, size_t *resid)
{
struct dosfile *df;
int got;
static int tc = 0;

df = (struct dosfile *) f->f_fsdata;

if (!(tc++ % 4))
twiddle();

if ((unsigned long) addr >= 0x10000) {
u_int lsize = size;

while (lsize > 0) {
u_int tsize;
size_t tgot;
char *p = addr;

tsize = lsize;

if (tsize > DISKBUFSIZE)
tsize = DISKBUFSIZE;

alloc_diskbuf(dos_read);

tgot = dosread(df->doshandle, diskbufp, tsize);
if (tgot < 0) {
#ifdef DEBUG
printf("DOS error %d\n", doserrno);
#endif
return dos2errno();
}
memcpy(p, diskbufp, tgot);

p += tgot;
lsize -= tgot;

if (tgot != tsize)
break; /* EOF */
}
got = size - lsize;
} else {
got = dosread(df->doshandle, addr, size);

if (got < 0) {
#ifdef DEBUG
printf("DOS error %d\n", doserrno);
#endif
return dos2errno();
}
}

df->off += got;
size -= got;

if (resid)
*resid = size;
return 0;
}

__compactcall int
dos_close(struct open_file *f)
{
struct dosfile *df;
df = (struct dosfile *) f->f_fsdata;

dosclose(df->doshandle);

if (df)
dealloc(df, sizeof(*df));
return 0;
}

__compactcall int
dos_write(struct open_file *f, void *start, size_t size, size_t *resid)
{
return EROFS;
}

__compactcall int
dos_stat(struct open_file *f, struct stat *sb)
{
sb->st_mode = 0444;
sb->st_nlink = 1;
sb->st_uid = 0;
sb->st_gid = 0;
sb->st_size = -1;
return 0;
}

__compactcall off_t
dos_seek(struct open_file *f, off_t offset, int where)
{
struct dosfile *df;
int doswhence, res;
#ifdef DOS_CHECK
int checkoffs;
#endif
df = (struct dosfile *) f->f_fsdata;

switch (where) {
case SEEK_SET:
doswhence = 0;
#ifdef DOS_CHECK
checkoffs = offset; /* don't trust DOS */
#endif
break;
case SEEK_CUR:
doswhence = 1;
#ifdef DOS_CHECK
checkoffs = df->off + offset;
#endif
break;
case SEEK_END:
doswhence = 2;
#ifdef DOS_CHECK
checkoffs = -1; /* we dont know len */
#endif
break;
default:
errno = EOFFSET;
return -1;
}
res = dosseek(df->doshandle, offset, doswhence);
if (res == -1) {
errno = dos2errno();
return -1;
}
#ifdef DOS_CHECK
if ((checkoffs != -1) && (res != checkoffs)) {
printf("dosfile: unexpected seek result (%d+%d(%d)=%d)\n",
df->off, offset, where, res);
errno = EOFFSET;
return -1;
}
#endif
df->off = res;
return res;
}