#include <u.h>#include <libc.h>#include <auth.h> voidusage(void){	fprint(2, "usage: newns [-ad] [-n namespace] [cmd [args...]]\n");	exits("usage");} static introoted(char *s){	if(s[0] == '/')		return 1;	if(s[0] == '.' && s[1] == '/')		return 1;	if(s[0] == '.' && s[1] == '.' && s[2] == '/')		return 1;	return 0;} voidmain(int argc, char **argv){	extern int newnsdebug;	char *defargv[] = { "/bin/rc", "-i", nil };	char *nsfile, err[ERRMAX];	int add; 	rfork(RFNAMEG);	add = 0;	nsfile = "/lib/namespace";	ARGBEGIN{	case 'a':		add = 1;		break;	case 'd':		newnsdebug = 1;		break;	case 'n':		nsfile = ARGF();		break;	default:		usage();		break;	}ARGEND	if(argc == 0)		argv = defargv;	if (add)		addns(getuser(), nsfile);	else		newns(getuser(), nsfile);	exec(argv[0], argv);	if(!rooted(argv[0])){		rerrstr(err, sizeof err);		exec(smprint("/bin/%s", argv[0]), argv);		errstr(err, sizeof err);	}	sysfatal("exec: %s: %r", argv[0]);}