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/*-
* Copyright (c) 2023 Christos Zoulas
* 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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``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 FOUNDATION OR CONTRIBUTORS
* 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.
*/
/*
* Parse SIM-H tape files
* http://simh.trailing-edge.com/docs/simh_magtape.pdf
*/
#ifndef TEST
#include "file.h"
#ifndef lint
FILE_RCSID("@(#)$File: is_simh.c,v 1.10 2023/07/27 19:39:55 christos Exp $")
#endif
#include <string.h>
#include <stddef.h>
#include "magic.h"
#else
#include <stdint.h>
#include <sys/types.h>
#include <string.h>
#include <stddef.h>
#define CAST(a, b) (a)(b)
#endif
#ifdef DEBUG
#include <stdio.h>
#define DPRINTF(fmt, ...) printf(fmt, __VA_ARGS__)
#else
#define DPRINTF(fmt, ...)
#endif
/*
* if SIMH_TAPEMARKS == 0:
* check all the records and tapemarks
* otherwise:
* check only up-to the number of tapemarks specified
*/
#ifndef SIMH_TAPEMARKS
#define SIMH_TAPEMARKS 10
#endif
typedef union {
char s[4];
uint32_t u;
} myword;
static myword simh_bo;
#define NEED_SWAP (simh_bo.u == CAST(uint32_t, 0x01020304))
/*
* swap an int
*/
static uint32_t
swap4(uint32_t sv)
{
myword d, s;
s.u = sv;
d.s[0] = s.s[3];
d.s[1] = s.s[2];
d.s[2] = s.s[1];
d.s[3] = s.s[0];
return d.u;
}
static uint32_t
getlen(const unsigned char **uc)
{
uint32_t n;
memcpy(&n, *uc, sizeof(n));
*uc += sizeof(n);
if (NEED_SWAP)
n = swap4(n);
if (n == 0xffffffff) /* check for End of Medium */
return n;
n &= 0x00ffffff; /* keep only the record len */
if (n & 1)
n++;
return n;
}
static int
simh_parse(const unsigned char *uc, const unsigned char *ue)
{
uint32_t nbytes, cbytes;
const unsigned char *orig_uc = uc;
size_t nt = 0, nr = 0;
(void)memcpy(simh_bo.s, "\01\02\03\04", 4);
while (ue - uc >= CAST(ptrdiff_t, sizeof(nbytes))) {
nbytes = getlen(&uc);
if ((nt > 0 || nr > 0) && nbytes == 0xFFFFFFFF)
/* EOM after at least one record or tapemark */
break;
if (nbytes == 0) {
nt++; /* count tapemarks */
#if SIMH_TAPEMARKS
if (nt == SIMH_TAPEMARKS)
break;
#endif
continue;
}
/* handle a data record */
uc += nbytes;
if (ue - uc < CAST(ptrdiff_t, sizeof(nbytes)))
break;
cbytes = getlen(&uc);
if (nbytes != cbytes)
return 0;
nr++;
}
if (nt * sizeof(uint32_t) == CAST(size_t, uc - orig_uc))
return 0; /* All examined data was tapemarks (0) */
if (nr == 0) /* No records */
return 0;
return 1;
}
#ifndef TEST
int
file_is_simh(struct magic_set *ms, const struct buffer *b)
{
const unsigned char *uc = CAST(const unsigned char *, b->fbuf);
const unsigned char *ue = uc + b->flen;
int mime = ms->flags & MAGIC_MIME;
if ((ms->flags & (MAGIC_APPLE|MAGIC_EXTENSION)) != 0)
return 0;
if (!simh_parse(uc, ue))
return 0;
if (mime == MAGIC_MIME_ENCODING)
return 1;
if (mime) {
if (file_printf(ms, "application/SIMH-tape-data") == -1)
return -1;
return 1;
}
if (file_printf(ms, "SIMH tape data") == -1)
return -1;
return 1;
}
#else
#include <sys/types.h>
#include <sys/stat.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdint.h>
#include <err.h>
int
main(int argc, char *argv[])
{
int fd;
struct stat st;
unsigned char *p;
if ((fd = open(argv[1], O_RDONLY)) == -1)
err(EXIT_FAILURE, "Can't open `%s'", argv[1]);
if (fstat(fd, &st) == -1)
err(EXIT_FAILURE, "Can't stat `%s'", argv[1]);
if ((p = CAST(char *, malloc(st.st_size))) == NULL)
err(EXIT_FAILURE, "Can't allocate %jd bytes",
(intmax_t)st.st_size);
if (read(fd, p, st.st_size) != st.st_size)
err(EXIT_FAILURE, "Can't read %jd bytes",
(intmax_t)st.st_size);
printf("is simh %d\n", simh_parse(p, p + st.st_size));
return 0;
}
#endif
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