🚀 go-pugleaf

In article <1992Jul29.125540.7401@hou.amoco.com> jim@n5ial.chi.il.us writes:
>
>I've seen lots of programs (usually shareware types) that allow you to
>make configuration changes, insert registration info, etc., directly into
>the compiled exe file.  that is, instead of having a config file hanging
>around, the exe itself is modified to include the new config info.
>how would one go about doing this?  btw, the program in question is in
>C, and uses Turbo C++ version 1.0.
I had written a shareware program that writes changes directly to the
program file.  Here's how:  create a data structure holding all
information you wish to change ( D in example), this allows all pertinent
data to be stored in one place, and it can easily be read/written to disk.
 
To figure out the offset:  (DEFAULT_OFFSET in example)  compile the
program, then use a program such as LIST to scan for a sequence of
matching bytes ( 100 118 138 )  The HEX DUMP mode of LIST is handy.
Next, go back to your source file, and update the correct offset.
An alternative way to figure out the offset is to use info from .map files.
 
It's very important to keep the variable D initialized in the program
because most compilers by default do not store un-initialized data as part
of the exe (to reduce size).
 
Here are relevant pieces of code from my program:
//------------------------------------------------------------------------
#define DEFAULT_OFFSET 0xAA8A
typedef struct
{
  char nr_factor;
  unsigned minimum;
  unsigned maximum;
  unsigned duration;
  long length;
  char fancy;
  char process;
  char playfile;
  char overwrite;
  unsigned sbport;
  char endpause;
} DEFAULTS;
//.........................................................................
DEFAULTS D =       {100, 118, 138, 3600, 200, YES, YES, 3, NO, 0x220, YES};
DEFAULTS FACTORY = {100, 118, 138, 3600, 200, YES, YES, 3, NO, 0x220, YES};
//.........................................................................
void fsavedefaults(char *program_name)
{
  FILE *fptr;
  if ((fptr = fopen (program_name, "rb+")) != NULL)
  {
    printf ("Saving new defaults to %s\n", program_name);
    fseek (fptr, DEFAULT_OFFSET, SEEK_SET);
    fwrite (&D, sizeof(D), 1, fptr);
  }
else show_error (9, program_name);
  fclose (fptr);
}
//------------------------------------------------------------------------
The program  can be obtained from most ftp sites as nohiss10.zip.  I'd be
happy to provide the full source code via email.  BTW, the complete
path\program_name is stored in argv[0] (i believe you only get the path 
from dos 3.0 or higher but that's good enough)
 
-Andy Hakim
<cosc16to@menudo.uh.edu>