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TAPE: Make ATTACH time validation check more robust

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- Different systems used tape marks in different ways that are now
  tolerated (multiple successive ones located on different parts of
  the tape, etc.)
- Always validate beginning and end of record length indicators to avoid
  moving into invalidly structured tape data
This commit is contained in:
Mark Pizzolato 2019-03-30 09:27:02 -07:00
parent e56b5f05e7
commit 98f6aae31a
1 changed files with 144 additions and 86 deletions
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230
sim_tape.c
View file

@ -824,7 +824,7 @@ else switch (f) { /* otherwise the read me
break;
}
uptr->pos = uptr->pos + sizeof (t_mtrlnt); /* space over the marker */
uptr->pos += sizeof (t_mtrlnt); /* space over the marker */
if (*bc == MTR_TMK) { /* if the value is a tape mark */
status = MTSE_TMK; /* then quit with tape mark status */
@ -865,6 +865,34 @@ else switch (f) { /* otherwise the read me
if (runaway_counter <= 0) /* if a tape runaway occurred */
status = MTSE_RUNAWAY; /* then report it */
if (status == MTSE_OK) { /* Validate the reverse record size */
t_addr saved_pos = (t_addr)sim_ftell(uptr->fileref);
t_mtrlnt rev_lnt;
if (sim_fseek (uptr->fileref, uptr->pos - sizeof (t_mtrlnt), SEEK_SET)){ /* then seek to the end of record size; if it fails */
status = sim_tape_ioerr (uptr); /* then quit with I/O error status */
break;
}
sim_fread (&rev_lnt, /* get the reverse length */
sizeof (t_mtrlnt),
1,
uptr->fileref);
if (ferror (uptr->fileref)) { /* if a file I/O error occurred */
status = sim_tape_ioerr (uptr); /* report the error and quit */
break;
}
if (sim_fseek (uptr->fileref, saved_pos, SEEK_SET)){ /* then seek back to the beginning of the data; if it fails */
status = sim_tape_ioerr (uptr); /* then quit with I/O error status */
break;
}
if (rev_lnt != *bc) { /* size mismatch? */
status = MTSE_INVRL;
uptr->pos -= (sizeof (t_mtrlnt) + *bc + sizeof (t_mtrlnt));
MT_SET_PNU (uptr); /* pos not upd */
}
}
break; /* otherwise the operation succeeded */
case MTUF_F_TPC:
@ -925,7 +953,7 @@ else switch (f) { /* otherwise the read me
MT_CLR_INMRK (uptr); /* Not within an AWS tapemark */
memset (&awshdr, 0, sizeof (awshdr));
rdcnt = sim_fread (&awshdr, sizeof (t_awslnt), 3, uptr->fileref);
*bc = awshdr.nxtlen; /* save rec lnt */
*bc = 0;
if (ferror (uptr->fileref)) { /* error? */
MT_SET_PNU (uptr); /* pos not upd */
@ -938,16 +966,35 @@ else switch (f) { /* otherwise the read me
status = MTSE_EOM;
break;
}
uptr->pos = uptr->pos + sizeof (t_awshdr); /* spc over AWS header */
if (awshdr.rectyp == AWS_TMK) /* tape mark? */
uptr->pos += sizeof (t_awshdr); /* spc over AWS header */
if (awshdr.rectyp == AWS_TMK) { /* tape mark? */
status = MTSE_TMK;
MT_SET_INMRK (uptr); /* within an AWS tapemark */
}
else
if (awshdr.rectyp == AWS_REC) /* tape data record */
uptr->pos = uptr->pos + awshdr.nxtlen; /* spc over record */
else {
if (awshdr.rectyp != AWS_REC) { /* Unknown record type */
MT_SET_PNU (uptr); /* pos not upd */
status = MTSE_INVRL;
}
else { /* tape data record */
t_addr saved_pos;
*bc = awshdr.nxtlen; /* save rec lnt */
uptr->pos += awshdr.nxtlen; /* spc over record */
memset (&awshdr, 0, sizeof (t_awslnt));
saved_pos = (t_addr)sim_ftell (uptr->fileref);
(void)sim_fseek (uptr->fileref, uptr->pos, SEEK_SET); /* for read */
(void)sim_fread (&awshdr, sizeof (t_awslnt), 3, uptr->fileref);
if (awshdr.rectyp == AWS_TMK)
MT_SET_INMRK (uptr); /* within an AWS tapemark */
if (awshdr.prelen != *bc) {
status = MTSE_INVRL;
uptr->pos = saved_pos - sizeof (t_awslnt);
MT_CLR_INMRK (uptr); /* not within an AWS tapemark */
}
else
(void)sim_fseek (uptr->fileref, saved_pos, SEEK_SET); /* Move back to the data */
}
break;
default:
@ -1175,7 +1222,7 @@ else switch (f) { /* otherwise the read me
break;
case MTUF_F_AWS:
sbc = 0;
*bc = sbc = 0;
while ((sbc == 0) && (status == MTSE_OK)) {
if (sim_tape_bot (uptr)) { /* if we start at BOT */
status = MTSE_BOT; /* then we're done */
@ -1184,18 +1231,22 @@ else switch (f) { /* otherwise the read me
(void)sim_fseek (uptr->fileref, uptr->pos, SEEK_SET);/* position */
memset (&awshdr, 0, sizeof (awshdr));
rdcnt = sim_fread (&awshdr, sizeof (t_awslnt), 3, uptr->fileref);
*bc = awshdr.prelen; /* save rec lnt */
if (ferror (uptr->fileref)) { /* error? */
status = sim_tape_ioerr (uptr);
break;
}
if (feof (uptr->fileref)) { /* eof? */
status = MTSE_EOM;
if ((uptr->pos > sizeof (t_awshdr)) &&
(uptr->pos >= sim_fsize (uptr->fileref)))
uptr->pos -= sizeof (t_awshdr);
break;
(uptr->pos >= sim_fsize (uptr->fileref))) {
if (MT_TST_INMRK (uptr)) {
status = MTSE_TMK;
MT_CLR_INMRK (uptr);
uptr->pos -= sizeof (awshdr);
}
else
status = MTSE_EOM; /* then we're done */
break;
}
}
if ((rdcnt != 3) ||
((awshdr.rectyp != AWS_REC) &&
@ -1203,10 +1254,11 @@ else switch (f) { /* otherwise the read me
status = MTSE_INVRL;
break;
}
sbc = *bc; /* extract the record length */
if (MT_TST_INMRK (uptr)) /* already in a tapemark? */
awshdr.rectyp = AWS_REC;
MT_CLR_INMRK (uptr); /* No longer in a tapemark */
*bc = (awshdr.rectyp == AWS_REC) ? awshdr.prelen : 0;/* save rec lnt */
sbc = *bc; /* extract the record length */
if ((awshdr.rectyp != AWS_TMK) ||
(awshdr.prelen == 0)) {
uptr->pos -= sizeof (t_awshdr); /* position to the start of the record */
@ -1284,8 +1336,10 @@ sim_debug_unit (ctx->dbit, uptr, "sim_tape_rdrecf(unit=%d, buf=%p, max=%d)\n", (
opos = uptr->pos; /* old position */
st = sim_tape_rdrlfwd (uptr, &tbc); /* read rec lnt */
if (st != MTSE_OK)
if (st != MTSE_OK) {
*bc = 0;
return st;
}
*bc = rbc = MTR_L (tbc); /* strip error flag */
if (rbc > max) { /* rec out of range? */
MT_SET_PNU (uptr);
@ -1350,8 +1404,10 @@ if (ctx == NULL) /* if not properly attac
sim_debug_unit (ctx->dbit, uptr, "sim_tape_rdrecr(unit=%d, buf=%p, max=%d)\n", (int)(uptr-ctx->dptr->units), buf, max);
st = sim_tape_rdrlrev (uptr, &tbc); /* read rec lnt */
if (st != MTSE_OK)
if (st != MTSE_OK) {
*bc = 0;
return st;
}
*bc = rbc = MTR_L (tbc); /* strip error flag */
if (rbc > max) /* rec out of range? */
return MTSE_INVRL;
@ -1490,7 +1546,7 @@ sim_fwrite (&awshdr, sizeof (t_awslnt), 3, uptr->fileref);
if (bc)
sim_fwrite (buf, sizeof (uint8), bc, uptr->fileref);
uptr->pos += sizeof (awshdr) + bc;
if ((!replacing_record) | (bc == 0)) {
if ((!replacing_record) || (bc == 0)) {
awshdr.prelen = bc;
awshdr.nxtlen = 0;
awshdr.rectyp = AWS_TMK;
@ -1567,7 +1623,6 @@ if (sim_tape_wrp (uptr)) /* write prot? */
if (MT_GET_FMT (uptr) == MTUF_F_P7B) /* cant do P7B */
return MTSE_FMT;
if (MT_GET_FMT (uptr) == MTUF_F_AWS) {
sim_tape_aws_wrdata (uptr, NULL, 0);
sim_set_fsize (uptr->fileref, uptr->pos);
result = MTSE_OK;
}
@ -2766,8 +2821,8 @@ const char *mtse_errors[] = {
"no error",
"tape mark",
"unattached",
"IO error",
"invalid rec lnt",
"I/O error",
"invalid record length",
"invalid format",
"beginning of tape",
"end of medium",
@ -2790,46 +2845,84 @@ t_addr saved_pos = uptr->pos;
uint32 record_in_file = 0;
uint32 data_total = 0;
uint32 tapemark_total = 0;
uint32 tapemark_seen = 0;
uint32 record_total = 0;
uint32 unique_record_sizes = 0;
t_stat r = SCPE_OK;
uint8 *buf = NULL;
t_stat r_f;
t_stat r_r;
t_stat r_s;
uint8 *buf_f = NULL;
uint8 *buf_r = NULL;
uint32 *rec_sizes = NULL;
t_mtrlnt bc_f;
t_mtrlnt bc_r;
t_mtrlnt bc_s;
t_mtrlnt bc;
t_addr pos_f;
t_addr pos_r;
t_mtrlnt max = MTR_MAXLEN;
t_bool prior_was_tapemark = FALSE;
if (!(uptr->flags & UNIT_ATT))
return SCPE_UNATT;
buf = (uint8 *)malloc (max);
if (buf == NULL)
buf_f = (uint8 *)malloc (max);
if (buf_f == NULL)
return SCPE_MEM;
buf_r = (uint8 *)malloc (max);
if (buf_r == NULL) {
free (buf_f);
return SCPE_MEM;
}
rec_sizes = (uint32 *)calloc (max + 1, sizeof (*rec_sizes));
if (rec_sizes == NULL) {
free (buf);
free (buf_f);
free (buf_r);
return SCPE_MEM;
}
r = sim_tape_rewind (uptr);
while (r == SCPE_OK) {
r = sim_tape_rdrecf (uptr, buf, &bc, max);
switch (r) {
pos_f = uptr->pos;
r_f = sim_tape_rdrecf (uptr, buf_f, &bc_f, max);
switch (r_f) {
case MTSE_OK: /* no error */
++record_total;
data_total += bc;
if (rec_sizes[bc] == 0)
++unique_record_sizes;
++rec_sizes[bc];
r = SCPE_OK;
prior_was_tapemark = FALSE;
break;
case MTSE_TMK: /* tape mark */
++tapemark_total;
if (prior_was_tapemark)
r = MTSE_LEOT;
if (r_f == MTSE_OK)
++record_total;
else
r = SCPE_OK;
prior_was_tapemark = TRUE;
++tapemark_total;
data_total += bc_f;
if (bc_f != 0) {
if (rec_sizes[bc_f] == 0)
++unique_record_sizes;
++rec_sizes[bc_f];
}
r_r = sim_tape_rdrecr (uptr, buf_r, &bc_r, max);
pos_r = uptr->pos;
if (r_r != r_f) {
sim_printf ("Forward Record Read returned: %s, Reverse read returned: %s\n", sim_tape_error_text (r_f), sim_tape_error_text (r_r));
break;
}
if (bc_f != bc_r) {
sim_printf ("Forward Record Read record lemgtj: %d, Reverse read record length: %d\n", bc_f, bc_r);
break;
}
if (0 != memcmp (buf_f, buf_r, bc_f)) {
sim_printf ("%d byte record contents differ when read forward amd backwards start from position %" T_ADDR_FMT "u\n", bc_f, pos_f);
break;
}
if (pos_f != pos_r) {
sim_printf ("Unexpected tape file position between forward and reverse record read: (%" T_ADDR_FMT "u, %" T_ADDR_FMT "u\n", pos_f, pos_r);
break;
}
r_s = sim_tape_sprecf (uptr, &bc_s);
if (r_s != r_f) {
sim_printf ("Unexpected Space Record Status: %s vs %s\n", sim_tape_error_text (r_s), sim_tape_error_text (r_f));
break;
}
if (bc_r != bc_r) {
sim_printf ("Unexpected Space Record Length: %d vs %d\n", bc_s, bc_f);
break;
}
r = SCPE_OK;
break;
case MTSE_INVRL: /* invalid rec lnt */
case MTSE_FMT: /* invalid format */
@ -2839,14 +2932,16 @@ while (r == SCPE_OK) {
case MTSE_LEOT: /* Logical End Of Tape */
case MTSE_RUNAWAY: /* tape runaway */
default:
r = r_f;
break;
case MTSE_EOM: /* end of medium */
r = r_f;
break;
}
}
if (((r != MTSE_EOM) && (r != MTSE_LEOT)) || (sim_switches & SWMASK ('V')) ||
if ((r != MTSE_EOM) || (sim_switches & SWMASK ('V')) ||
((uint32)(sim_fsize_ex (uptr->fileref) - (t_offset)uptr->pos) > fmts[MT_GET_FMT (uptr)].eom_remnant) ||
(unique_record_sizes > 2 * tapemark_seen)) {
(unique_record_sizes > 2 * tapemark_total)) {
uint32 remaining_data = (uint32)(sim_fsize_ex (uptr->fileref) - (t_offset)uptr->pos);
sim_printf ("Tape Image '%s' scanned as %s format.\n", uptr->filename, fmts[MT_GET_FMT (uptr)].name);
@ -2857,62 +2952,25 @@ if (((r != MTSE_EOM) && (r != MTSE_LEOT)) || (sim_switches & SWMASK ('V')) ||
sim_printf ("%u bytes of tape data (%u records, %u tapemarks)\n",
data_total, record_total, tapemark_total);
if (record_total > 0) {
sim_printf ("Comprising:\n");
sim_printf ("Comprising (in record size order):\n");
for (bc = 0; bc <= max; bc++) {
if (rec_sizes[bc])
sim_printf ("%8u %u byte records\n", rec_sizes[bc], (uint32)bc);
}
}
if ((r != MTSE_EOM) && (r != MTSE_LEOT))
if (r != MTSE_EOM)
sim_printf ("Read Tape Record Returned Unexpected Status: %s\n", sim_tape_error_text (r));
if (remaining_data > fmts[MT_GET_FMT (uptr)].eom_remnant)
sim_printf ("%u bytes of unexamined data remain in the tape image file\n", remaining_data);
}
/* Try again reading backwards */
r = SCPE_OK;
tapemark_seen = tapemark_total;
while (r == SCPE_OK) {
r = sim_tape_rdrecr (uptr, buf, &bc, max);
switch (r) {
case MTSE_OK: /* no error */
--record_total;
data_total -= bc;
if (bc > max)
bc = max;
--rec_sizes[bc];
r = SCPE_OK;
break;
case MTSE_TMK: /* tape mark */
--tapemark_total;
r = SCPE_OK;
break;
case MTSE_BOT: /* beginning of tape */
break;
case MTSE_INVRL: /* invalid rec lnt */
case MTSE_FMT: /* invalid format */
case MTSE_RECE: /* error in record */
case MTSE_WRP: /* write protected */
case MTSE_LEOT: /* Logical End Of Tape */
case MTSE_RUNAWAY: /* tape runaway */
default:
break;
case MTSE_EOM: /* end of medium */
r = SCPE_OK;
break;
}
}
if ((record_total != 0) ||
(tapemark_total != 0) ||
(data_total != 0))
sim_printf ("Reverse read of the tape data is inconsistent with the forward read.\n");
if (unique_record_sizes > 2 * tapemark_seen) {
if (unique_record_sizes > 2 * tapemark_total) {
sim_printf ("An unreasonable number of record sizes(%u) vs tape marks (%u) have been found\n", unique_record_sizes, tapemark_total);
sim_printf ("The tape format (%s) might not be correct for the '%s' tape image\n", fmts[MT_GET_FMT (uptr)].name, uptr->filename);
}
free (buf);
free (buf_f);
free (buf_r);
free (rec_sizes);
uptr->pos = saved_pos;
return SCPE_OK;