#include <u.h>#include <libc.h> int touch(int, char *);ulong now; voidusage(void){	fprint(2, "usage: touch [-c] [-t time] files\n");	exits("usage");} voidmain(int argc, char **argv){	char *t, *s;	int nocreate = 0;	int status = 0; 	now = time(0);	ARGBEGIN{	case 't':		t = EARGF(usage());		now = strtoul(t, &s, 0);		if(s == t || *s != '\0')			usage();		break;	case 'c':		nocreate = 1;		break;	default:			usage();	}ARGEND 	if(!*argv)		usage();	while(*argv)		status += touch(nocreate, *argv++);	if(status)		exits("touch");	exits(0);} touch(int nocreate, char *name){	Dir stbuff;	int fd; 	nulldir(&stbuff);	stbuff.mtime = now;	if(dirwstat(name, &stbuff) >= 0)		return 0;	if(nocreate){		fprint(2, "touch: %s: cannot wstat: %r\n", name);		return 1;	}	if((fd = create(name, OREAD|OEXCL, 0666)) < 0){		fprint(2, "touch: %s: cannot create: %r\n", name);		return 1;	}	dirfwstat(fd, &stbuff);	close(fd);	return 0;}