/*
 *	This is a quick hack to zap strings in an executable file
 *	by replacing their first byte with a null character.  In most
 *	cases, this will effectively turn them into null strings.
 *	This is useful to prevent venders from bombarding you with
 *	irritating startup messages everytime you run their program.
 *	Grrr....
 *
 */

#include <stdio.h>

main (argc, argv)
int argc;
char *argv[];
{
    FILE *fin = NULL;
    register int ch;
    register char *sp;
    long resync;
    
    if (argc != 3) {
	Fatal (fin, "usage: zapstring <string> <file>");
    }
    fin = fopen (argv[2], "r+");
    sp = argv[1];
    if (fin == NULL) {
	Fatal (fin, "zapstring: can't open file");
    }
    while ((ch = fgetc (fin)) != EOF) {
	if (ch == *sp) {
	    resync = ftell (fin);
	    while ((ch = fgetc (fin)) != EOF && ch == *++sp && *sp != '\000');
	    if (ch != EOF && *sp == '\000') {
		if (fseek (fin, resync - 1, 0) != 0) {
		    Fatal (fin, "zapstring: can't resync!");
		}
		if (fputc ('\000', fin) != '\000') {
		    Fatal (fin, "zapstring: patch failed in fputc()!");
		}
		break;
	    } else {
		sp = argv[1];
		if (fseek (fin, resync, 0) != 0) {
		    Fatal (fin, "zapstring: can't resync!");
		}
	    }
	}
    }
    fclose (fin);
    exit (0);
}

	
Fatal (fin, why)
FILE *fin;
char *why;
{
    fprintf (stderr, "%s\n", why);
    fclose (fin);
    exit (1);
}