---notas em códigos 'auto-replicáveis', por m0nad---
código do ken thompson , auto replicável:
http://www.azillionmonkeys.com/qed/self3_c.txt

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m0nad@m0nad-notebook:~/projects/selfreplica$ gcc -o selfreplica selfreplica.c
selfreplica.c: In function ‘main’:
selfreplica.c:26: warning: incompatible implicit declaration of built-in function ‘printf’
m0nad@m0nad-notebook:~/projects/selfreplica$ ./selfreplica
char s[] = {
0x6D, 0x61, 0x69, 0x6E, 0x28, 0x29, 0x20, 0x7B,
0x0D, 0x0A, 0x69, 0x6E, 0x74, 0x20, 0x69, 0x3B,
0x0D, 0x0A, 0x09, 0x70, 0x72, 0x69, 0x6E, 0x74,
0x66, 0x28, 0x22, 0x63, 0x68, 0x61, 0x72, 0x20,
0x73, 0x5B, 0x5D, 0x20, 0x3D, 0x20, 0x7B, 0x22,
0x29, 0x3B, 0x0D, 0x0A, 0x09, 0x66, 0x6F, 0x72,
0x28, 0x69, 0x3D, 0x30, 0x3B, 0x73, 0x5B, 0x69,
0x5D, 0x21, 0x3D, 0x27, 0x5C, 0x30, 0x27, 0x3B,
0x69, 0x2B, 0x2B, 0x29, 0x20, 0x7B, 0x0D, 0x0A,
0x09, 0x09, 0x69, 0x66, 0x28, 0x20, 0x28, 0x69,
0x26, 0x37, 0x29, 0x3D, 0x3D, 0x30, 0x20, 0x29,
0x20, 0x70, 0x72, 0x69, 0x6E, 0x74, 0x66, 0x28,
0x22, 0x5C, 0x6E, 0x22, 0x29, 0x3B, 0x0D, 0x0A,
0x09, 0x09, 0x70, 0x72, 0x69, 0x6E, 0x74, 0x66,
0x28, 0x22, 0x30, 0x78, 0x25, 0x30, 0x32, 0x58,
0x2C, 0x20, 0x22, 0x2C, 0x73, 0x5B, 0x69, 0x5D,
0x29, 0x3B, 0x0D, 0x0A, 0x09, 0x7D, 0x0D, 0x0A,
0x09, 0x70, 0x72, 0x69, 0x6E, 0x74, 0x66, 0x28,
0x22, 0x30, 0x5C, 0x6E, 0x7D, 0x3B, 0x5C, 0x6E,
0x25, 0x73, 0x5C, 0x6E, 0x22, 0x2C, 0x73, 0x29,
0x3B, 0x0D, 0x0A, 0x7D, 0
};
main() {
int i;
    printf("char s[] = {");
    for(i=0;s[i]!='\0';i++) {
        if( (i&7)==0 ) printf("\n");
        printf("0x%02X, ",s[i]);
    }
    printf("0\n};\n%s\n",s);
}
m0nad@m0nad-notebook:~/projects/selfreplica$
-------------------------
eu olhei e falei 'style', entendi o conceito mas implementei de outra forma, fiz um oneliner em perl, pra fazer um estilo 'shellcode' dos valores ascii. =p
-------------------------
m0nad@m0nad-notebook:~/projects/selfreplica$ cat > 1.c
int main () { };                                                                                 
^C
m0nad@m0nad-notebook:~/projects/selfreplica$ cat 1.c | perl -ne '@a = split //, $_;printf "\\x%02x", unpack("C*", $_) foreach (@a)';echo
\x69\x6e\x74\x20\x6d\x61\x69\x6e\x20\x28\x29\x20\x7b\x20\x7d\x3b\x0a
m0nad@m0nad-notebook:~/projects/selfreplica$ 

-------------------------
ok, conferi se isso iria retornar oque eu queria
-------------------------
m0nad@m0nad-notebook:~/projects/selfreplica$ cat selfreplica-m0nad1.c
char notevil[] = "\x69\x6e\x74\x20\x6d\x61\x69\x6e\x20\x28\x29\x20\x7b\x20\x7d\x3b\x0a";
#include <stdio.h>
int
main ()
{
   printf ("%s", notevil);
   return 0;
}

m0nad@m0nad-notebook:~/projects/selfreplica$ gcc -o selfreplica-m0nad1 selfreplica-m0nad1.c
m0nad@m0nad-notebook:~/projects/selfreplica$ ./selfreplica-m0nad1
int main () { };
m0nad@m0nad-notebook:~/projects/selfreplica$
-------------------------
ieí!!
ok, agora vou fazer um notevil do próprio código, mas tem um problema ai
preciso imprimir o código em C e o do 'notevil', ok , relendo o código do ken thompson...
-------------------------

	for(i=0;s[i]!='\0';i++) {
		if( (i&7)==0 ) printf("\n");
		printf("0x%02X, ",s[i]);

	}
-------------------------
ou seja, ele cria a formatação do próprio hexadecimal, enquanto o nao chega a o final, q eh um nullbyte , style neh?

bem, fiz algo parecido, segue o código.
-------------------------
m0nad@m0nad-notebook:~/projects/selfreplica$ cat selfreplica-m0nad-final.c
char notevil[] = "\x23\x69\x6e\x63\x6c\x75\x64\x65\x20\x3c\x73\x74\x64\x69\x6f\x2e\x68\x3e\x0a\x69\x6e\x74\x0a\x6d\x61\x69\x6e\x20\x28\x29\x0a\x7b\x0a\x20\x20\x69\x6e\x74\x20\x69\x20\x3d\x20\x30\x20\x3b\x0a\x20\x20\x70\x72\x69\x6e\x74\x66\x20\x28\x22\x63\x68\x61\x72\x20\x6e\x6f\x74\x65\x76\x69\x6c\x5b\x5d\x20\x3d\x20\x5c\x22\x22\x29\x3b\x0a\x20\x20\x77\x68\x69\x6c\x65\x20\x28\x6e\x6f\x74\x65\x76\x69\x6c\x5b\x69\x5d\x29\x20\x7b\x0a\x20\x20\x20\x20\x70\x72\x69\x6e\x74\x66\x20\x28\x22\x5c\x5c\x78\x25\x30\x32\x78\x22\x2c\x20\x6e\x6f\x74\x65\x76\x69\x6c\x5b\x69\x2b\x2b\x5d\x29\x3b\x0a\x20\x20\x7d\x0a\x20\x20\x70\x72\x69\x6e\x74\x66\x20\x28\x22\x5c\x22\x3b\x5c\x6e\x25\x73\x22\x2c\x20\x6e\x6f\x74\x65\x76\x69\x6c\x29\x3b\x0a\x20\x20\x72\x65\x74\x75\x72\x6e\x20\x30\x3b\x0a\x7d\x0a";
#include <stdio.h>
int
main ()
{
  int i = 0 ;
  printf ("char notevil[] = \"");
  while (notevil[i]) {
    printf ("\\x%02x", notevil[i++]);
  }
  printf ("\";\n%s", notevil);
  return 0;
}
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testando... :D
-------------------------

m0nad@m0nad-notebook:~/projects/selfreplica$ gcc -o selfreplica-m0nad-final selfreplica-m0nad-final.c
m0nad@m0nad-notebook:~/projects/selfreplica$ ./selfreplica-m0nad-final >teste
m0nad@m0nad-notebook:~/projects/selfreplica$ diff selfreplica-m0nad-final.c teste
m0nad@m0nad-notebook:~/projects/selfreplica$ 

-------------------------
:D
abraços galera.

happy hacking !