buff[9] = '$';  (void) binary((int) uc, buff + 10);  /* Print all the information */  printf("Stack Frame:\tPC = %04.4x\t\t   PSW = %s\n",         sp->pc, buff);  printf("\t\t\t\t\tStatus = ____ ODIT SZ_A _P_C\n");  printf("  ax	bx	cx	dx	di	si\n");  printf("  %04.4x\t%04.4x\t%04.4x\t%04.4x\t%04.4x\t%04.4x\n",         sp->retreg, sp->bx, sp->cx, sp->dx, sp->di, sp->si);  printf("  sp	bp	ss\n");  printf("  %04.4x\t%04.4x\t%04.4x\n",         sp->sp, sp->fp, sp->ss);  printf("  cs	ds	es\n");  printf("  %04.4x\t%04.4x\t%04.4x\n",         sp->cs, sp->ds, sp->es);  /* Store for future reference */  stackptr = sp->sp;  baseptr = sp->fp;  if (dbglvl > 0)	printf("\nStack pointer 0x%x, Base pointer 0x%x\n", stackptr, baseptr);}/* M a i n * * Main program */main(argc, argv)int argc;char *argv[];{  int j, fdc, fds;  char *cp, corefile[132], symbfile[132];  struct proc proc_entry;  struct mem_map mp_segs[NR_SEGS];  /* Initial set up */  if ((cp = strrchr(argv[0], '/')) == (char *) NULL)	cp = argv[0];  else	cp++;  strncpy(progname, cp, 19);  strncpy(corefile, CORE, 131);  strncpy(symbfile, AOUT, 131);  /* Parse arguments */  opterr = 0;  while ((j = getopt(argc, argv, "c:dps:tx:")) != EOF) {	switch (j & 0177) {	    case 'c':		opt_c = TRUE;		strncpy(corefile, optarg, 131);		break;	    case 'd':	opt_d = TRUE;	break;	    case 'p':	opt_p = TRUE;	break;	    case 's':		opt_s = TRUE;		strncpy(symbfile, optarg, 131);		break;	    case 't':	opt_t = TRUE;	break;	    case 'x':		dbglvl = atoi(optarg);		opt_x = TRUE;		break;	    case '?':	    default:		usage();		exit(1);		break;	}  }  /* We must have a core file */  if ((fdc = open(corefile, O_RDONLY)) == -1) {	fprintf(stderr, "Cannot open %s\n", corefile);	exit(1);  }  /* We'd like an a.out file or a symbol table */  if ((fds = open(symbfile, O_RDONLY)) == -1) {	if (opt_s)		j = FAILED;	else {		strncpy(symbfile, AOUT, 131);		if ((fds = open(symbfile, O_RDONLY)) == -1)			j = FAILED;		else			j = read_symbol(fds);	}  } else	j = read_symbol(fds);  /* Only fatal if we insisted */  if (opt_s && j == FAILED) {	fprintf(stderr, "Cannot find symbols in %s\n", symbfile);	exit(1);  }  /* Read the process table */  if (dbglvl > 0) {	printf("\n");	printf("Size of mproc entry %d\n", NR_SEGS * sizeof(struct mem_map));	printf("Size of process table %d\n", sizeof(proc_entry));  }  if (read(fdc, (char *) mp_segs, sizeof(mp_segs)) != sizeof(mp_segs) ||      read(fdc, (char *) &proc_entry,	 sizeof(struct proc)) != sizeof(struct proc)) {	fprintf(stderr, "Cannot open %s\n", corefile);	exit(1);  }  /* Do the work */#if 0  dump_maps(mp_segs);		/* duplicated in the kernel */  printf("\n");#endif  dump_maps(proc_entry.p_map);  printf("\n");  dump_registers(&proc_entry);  if (opt_t) {	printf("\n");	stack_trace(fdc);  }  if (opt_p) {	printf("\n");	dump_proc_table(&proc_entry);  }  if (opt_d) {	printf("\n");	dump_sym_tab(symtab);	dump_all_segs(fdc);  }  /* Wrap up */  (void) close(fdc);  if (fds != -1) (void) close(fds);  exit(0);  /* NOTREACHED */}/* P a r s e _ l i n e * * Parse a line of the symbol table */int parse_line(ps)char *ps;{  char c, s[80];  int j, k;  unsigned int u;  /* We must have space in the table */  if (maxsym == MAXSYM) return(FAILED);  /* Lines must be a minimum length to contain information */  if (strlen(ps) < 8) return(FAILED);  /* Lines must have a definite structure */  if (ps[1] != ' ' || ps[6] != ' ') return(FAILED);  for (j = 2; j < 6; j++)	if (!isxdigit(ps[j])) return(FAILED);  if (sscanf(ps, "%c %x %s", &c, &u, s) != 3) return (FAILED);  if (dbglvl > 0) printf("Address 0x%04.4x, label %s\n", u, s);  /* Load the symbol table in sorted order */  for (j = 0; j < maxsym; j++) {	if (u < symtab[j].addr) {		for (k = maxsym; k > j; k--) symtab[k] = symtab[k - 1];		break;	}  }  symtab[j].addr = u;  strncpy(symtab[j].label, s, SYMLEN);  maxsym++;  return(OK);}/* R e a d _ s y m b o l * * Read the symbol table */int read_symbol(fd)int fd;{  char sym[80], buff[BUFSIZ];  int j, k, m;  long int offset;  struct exec *ep;  struct nlist *np;  /* We collect only text symbols, since that's all that's needed here */  /* Initialise the buffer */  if ((j = read(fd, buff, BUFSIZ)) == 0 || j == -1) return(FAILED);  k = maxsym = 0;  /* Find out what we've got */  ep = (struct exec *) buff;  np = (struct nlist *) buff;  if (BADMAG(*ep)) {	/* Must be a separate symbol table */	while (TRUE) {		if (buff[k] == 'T') {			for (m = 0; m < 78; m++) {				sym[m] = buff[k];				if (++k == j) {					if ((j = read(fd, buff, BUFSIZ)) == 0 || j == -1)						break;					k = 0;				}				if (buff[k] == '\n') break;			}			sym[m + 1] = '\0';			(void) parse_line(sym);		}		if (++k == j) {			if ((j = read(fd, buff, BUFSIZ)) == 0 || j == -1)				break;			k = 0;		}	}  } else if (ep->a_syms != 0L) {	/* There's symbols in them thar hills */	offset = 8 * sizeof(long) + ep->a_text + ep->a_data;	if (lseek(fd, offset, 0) == -1L) return(FAILED);	/* Symbols are in an unsorted list */	while (read(fd, buff, sizeof(struct nlist)) == sizeof(struct nlist)) {		if (np->n_sclass == (N_TEXT + C_EXT)) {	/* external text symbols */			for (j = 0; j < maxsym; j++) {				if (np->n_value < symtab[j].addr) {					for (k = maxsym; k > j; k--)						symtab[k] = symtab[k - 1];					break;				}			}			symtab[j].addr = np->n_value;			strncpy(symtab[j].label, np->n_name, SYMLEN);			if (maxsym++ == MAXSYM) break;		}	}  } else if (opt_s)	return(FAILED);  if (dbglvl > 0) {	for (m = 0; m < maxsym; m++) printf("Addr 0x%04.4x, label %s\n",		       symtab[m].addr, symtab[m].label);	printf("Maxsym %d\n", maxsym);  }  return(OK);}/* S t a c k _ t r a c e * * Trace back down the stack frames. * * WARNING: very, very, non-portable code */void stack_trace(fd)int fd;{  int j;  unsigned int framepointer, lastpointer, returnvalue, end;  long int offset, bp;  /* Bp actually gives the offset from the base of the data segment */  bp = (long) (NR_SEGS * sizeof(struct mem_map)) + sizeof(struct proc)	+ lengths[0] + lengths[1] - bases[2];  if ((offset = lseek(fd, bp + (long int) baseptr, 0)) == -1L) return;  end = (bases[2] + lengths[2] - 1) & 0xffff;  if (dbglvl > 0)	printf("Baseptr %x, End %x, Bp %ld, Offset %ld\n", baseptr, end, bp, offset);  /* Print the header, then try to backtrace  */  printf("Stack back trace:\n\n");  printf("Frame address.  Contents.  Return address.");  if (maxsym != 0) printf("  Previous label.");  printf("\n");  lastpointer = baseptr;  while (TRUE) {	/* Read the frame pointer and return address values */	if (read(fd, (char *) &framepointer, sizeof(int)) == -1 ||	    read(fd, (char *) &returnvalue, sizeof(int)) == -1)		break;	/* Look up the return address - ignored if maxsym == 0 */	for (j = 0; j < maxsym; j++) {		if (symtab[j].addr >= returnvalue) break;	}	if (j > 0) j--;	printf("    0x%04.4x        0x%04.4x      0x%04.4x          %s\n",	       lastpointer, framepointer, returnvalue,	       (maxsym == 0) ? "" : symtab[j].label);	/* If the result is clearly invalid, quit */	if (framepointer == 0 || framepointer >= end || framepointer <= lastpointer)		break;	/* Otherwise try to move to the next frame base */	lastpointer = framepointer;	if ((offset = lseek(fd, bp + (long int) framepointer, 0)) == -1L || offset == 0L)		break;  }}/* U s a g e * * Usage message */void usage(){  fprintf(stderr, "Usage: %s [-dpt] [-c corefile] [-s symbfile]\n", progname);}