static char * main_source(char * data){strcpy(data, BAD_OS_COMMAND);return data;}void _main(){char * data;char data_buf[100]="";data=data_buf;data=main_source(data);system(data);}
static char * main_source(char * data){strcpy(data, GOOD_OS_COMMAND);return data;}static void main(){char * data;char data_buf[100]="";data=data_buf;data=main_source(data);system(data);}