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#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <time.h>
#include "bas.h"
int protect_vars = 1;
int protect_code = 1;
int shrinktable = 0;
int varname_char = 0x9b;
/* 32767 END */
unsigned char badcode[] = {
0xff, 0x7f, /* line number 32767 */
0x00, /* *bad* next-line offset */
0x06, /* next-statement offset */
0x15, /* END token */
0x16, /* end-of-line token */
};
void scramble_vars(void) {
int i;
if(!vntable_ok()) {
fprintf(stderr, "%s: Program already was variable-protected.\n", self);
exit(2);
}
if(shrinktable) {
if(verbose) fprintf(stderr, "Shrinking variable name table.\n");
adjust_vntable_size((vvstart - 1) - vnstart, (codestart - vvstart) / 8);
}
if(varname_char == -1) srand(time(NULL));
for(i = vnstart; i < vvstart - 1; i++)
if(varname_char == -1)
program[i] = (rand() >> 8) & 0xff;
else
program[i] = varname_char & 0xff;
if(verbose) {
i -= vnstart;
if(i) {
fprintf(stderr, "Replaced %d byte variable name table with ", i);
if(varname_char == -1)
fprintf(stderr, "random characters.\n");
else
fprintf(stderr, "character $%02x.\n", varname_char);
} else {
fprintf(stderr, "Can't protect variables because there are no variables.\n");
}
}
}
/* iterate over all the lines, insert a poisoned line 32767 just
before line 32768 */
void breakcode(void) {
int pos = codestart, oldpos = 0;
int offset, lineno = -1, tmpno = -1;
while(pos < filelen) {
lineno = tmpno;
tmpno = getword(pos);
if(tmpno == 32768) {
break;
} else {
offset = program[pos + 2];
if(!offset) {
fprintf(stderr, "%s: program already was code-protected.\n", self);
exit(2);
}
oldpos = pos;
pos += offset;
}
}
if(!oldpos) die("Can't protect code because there are no lines of code.");
if(lineno == 32767) die("Can't protect code because there is already a line 32767.");
/* pos is now the start of line 32768, move it up to make room for
the new line */
offset = sizeof(badcode);
memmove(program + pos + offset, program + pos, filelen);
/* insert new line */
memmove(program + pos, badcode, offset);
if(verbose)
fprintf(stderr, "Inserted line 32767 with invalid offset at file offset $%04x.\n", pos);
/* update pointers that would be affected by the code move */
stmcur += offset;
starp += offset;
filelen += offset;
update_header();
parse_header();
}
void print_help(void) {
fprintf(stderr, "Usage: %s [-v] [-nc|-nv] [-s] [-x[r|NN]] <inputfile> <outputfile>\n", self);
fprintf(stderr, " -v: Verbose.\n");
fprintf(stderr, " -nc: Don't protect code.\n");
fprintf(stderr, " -nv: Don't protect variable names.\n");
fprintf(stderr, " -s: Shrink variable name table to min size.\n");
fprintf(stderr, "-xNN: Hex code NN for variable names.\n");
fprintf(stderr, " -xr: Random variable names.\n");
fprintf(stderr, "Use - as a filename to read from stdin and/or write to stdout.\n");
}
void parse_args(int argc, char **argv) {
int opt, xopt_used = 0;
while( (opt = getopt(argc, argv, "vn:x:s")) != -1) {
switch(opt) {
case 'v': verbose = 1; break;
case 's': shrinktable = 1; break;
case 'n':
switch(optarg[0]) {
case 'c': protect_code = 0; break;
case 'v': protect_vars = 0; break;
default:
die("Invalid argument for -n (must be 'c' or 'v').");
}
break;
case 'x':
xopt_used = 1;
switch(optarg[0]) {
case 'r':
varname_char = -1; break;
case 0:
die("-x option requires a hex number or 'r'."); break;
default:
{
char *e;
varname_char = (int)strtol(optarg, &e, 16);
if(*e != 0 || varname_char > 0xff)
fprintf(stderr, "%s: Invalid hex value '%s' for -x option (range is 0 to ff).\n", self, optarg);
}
}
break;
default:
print_help();
exit(1);
}
}
if(!protect_code && !protect_vars) {
die("Nothing to do: -nc and -nv both given.");
}
if(!protect_vars) {
if(xopt_used)
die("-x option not valid with -nv.");
if(shrinktable)
die("-s option not valid with -nv.");
}
if(optind >= argc)
die("No input file given (use - for stdin).");
else
open_input(argv[optind]);
if(++optind >= argc)
die("No output file given (use - for stdout).");
else
output_filename = argv[optind];
}
int main(int argc, char **argv) {
set_self(*argv);
parse_general_args(argc, argv, print_help);
parse_args(argc, argv);
readfile();
parse_header();
if(verbose) {
fprintf(stderr, "Protecting program, ");
if(protect_vars && !protect_code)
fprintf(stderr, "variables only.\n");
else if(protect_code && !protect_vars)
fprintf(stderr, "code only.\n");
else
fprintf(stderr, "both code and variables.\n");
}
if(protect_vars) scramble_vars();
if(protect_code) breakcode();
open_output(output_filename);
writefile();
return 0; /* TODO: meaningful return status */
}
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