#include <u.h>#include <libc.h> int touch(int, char *); voidmain(int argc, char **argv){	int force = 1;	int status = 0; 	ARGBEGIN{	case 'c':	force = 0; break;	default:	goto usage; break;	}ARGEND	if(!*argv){usage:		fprint(2, "usage: touch [-c] files\n");		exits("usage");	}	while(*argv)		status += touch(force, *argv++);	if(status)		exits("touch");	exits(0);} touch(int force, char *name){	Dir stbuff;	char junk[1];	int fd; 	stbuff.length = 0;	stbuff.mode = 0666;	if (dirstat(name, &stbuff) < 0 && force == 0) {		fprint(2, "touch: %s: cannot stat: %r\n", name);		return 1;	}	if (stbuff.length == 0) {		if ((fd = create(name, 0, stbuff.mode)) < 0) {			fprint(2, "touch: %s: cannot create: %r\n", name);			return 1;		}		close(fd);		return 0;	}	if ((fd = open(name, ORDWR)) < 0) {		fprint(2, "touch: %s: cannot open: %r\n", name);		return 1;	}	if(read(fd, junk, 1) < 1) {		fprint(2, "touch: %s: read error: %r\n", name);		close(fd);		return 1;	}	seek(fd, 0L, 0);	if(write(fd, junk, 1) < 1 ) {		fprint(2, "touch: %s: write error: %r\n", name);		close(fd);		return 1;	}	close(fd);	return 0;}