#include <u.h>#include <libc.h> #define	DEFB	(8*1024) int	xflag;void	copy(char *from, char *to, int todir);void	copy1(int fdf, int fdt, char *from, char *to); voidmain(int argc, char *argv[]){	Dir dirb;	int todir, i; 	ARGBEGIN {	case 'x':		xflag++;		break;	default:		goto usage;	} ARGEND 	todir=0;	if(argc < 2)		goto usage;	if(dirstat(argv[argc-1], &dirb)==0 && (dirb.mode&CHDIR))		todir=1;	if(argc>2 && !todir){		fprint(2, "cp: %s not a directory\n", argv[argc-1]);		exits("bad usage");	}	for(i=0; i<argc-1; i++)		copy(argv[i], argv[argc-1], todir);	exits(0); usage:	fprint(2, "usage:\tcp [-x] fromfile tofile\n");	fprint(2, "\tcp [-x] fromfile ... todir\n");	exits("usage");} voidcopy(char *from, char *to, int todir){	Dir dirb, dirt;	char name[256];	int fdf, fdt;	char *cp; 	if(todir){		char *s, *elem;		elem=s=from;		while(*s++)			if(s[-1]=='/')				elem=s;		sprint(name, "%s/%s", to, elem);		to=name;	}	if(dirstat(from, &dirb)!=0){		fprint(2,"cp: can't stat %s: %r\n", from);		return;	}	if(xflag) {		if(dirstat(to, &dirt)==0)		if(dirb.qid.path==dirt.qid.path && dirb.qid.vers==dirt.qid.vers)		if(dirb.dev==dirt.dev && dirb.type==dirt.type){			fprint(2, "cp: %s and %s are the same file\n", from, to);			return;		}		fdf=open(from, OREAD);		if(fdf<0){			fprint(2, "cp: can't open %s: %r\n", from);			return;		}		if(dirb.mode&CHDIR) {			fdt=create(to, OREAD, dirb.mode);			if(fdt<0)				fprint(2, "cp: can't mkdir %s: %r\n", to);		} else {			remove(to);			fdt=create(to, OWRITE, dirb.mode);			if(fdt<0){				fprint(2, "cp: can't create %s: %r\n", to);				close(fdf);				return;			}			copy1(fdf, fdt, from, to);		}		close(fdf);		close(fdt);		cleanname(to);		cp = strrchr(to, '/');		if(cp)			cp++;		else			cp = to;		strncpy(dirb.name, cp, sizeof(dirb.name));		if(dirwstat(to, &dirb)==-1){			dirstat(to, &dirt);			strncpy(dirb.uid, dirt.uid, sizeof(dirb.uid));			if(dirwstat(to, &dirb)==0)				fprint(2, "cp: can't wstat uid %s: %r\n", to);			else{				strncpy(dirb.gid, dirt.gid, sizeof(dirb.gid));				if(dirwstat(to, &dirb)==0)					fprint(2, "cp: can't wstat uid or gid %s: %r\n", to);				else					fprint(2, "cp: can't wstat %s: %r\n", to);			}		}	} else {		if(dirb.mode&CHDIR){			fprint(2, "cp: %s is a directory\n", from);			return;		}		dirb.mode &= 0777;		if(dirstat(to, &dirt)==0)		if(dirb.qid.path==dirt.qid.path && dirb.qid.vers==dirt.qid.vers)		if(dirb.dev==dirt.dev && dirb.type==dirt.type){			fprint(2, "cp: %s and %s are the same file\n", from, to);			return;		}		fdf=open(from, OREAD);		if(fdf<0){			fprint(2, "cp: can't open %s: %r\n", from);			return;		}		fdt=create(to, OWRITE, dirb.mode);		if(fdt<0){			fprint(2, "cp: can't create %s: %r\n", to);			close(fdf);			return;		}		copy1(fdf, fdt, from, to);		close(fdf);		close(fdt);	}} voidcopy1(int fdf, int fdt, char *from, char *to){	char *buf;	long n, n1, rcount; 	buf = malloc(DEFB);	/* clear any residual error */	memset(buf, 0, ERRLEN);	errstr(buf);	for(rcount=0;; rcount++) {		n = read(fdf, buf, DEFB);		if(n <= 0)			break;		n1 = write(fdt, buf, n);		if(n1 != n) {			fprint(2, "cp: error writing %s: %r\n", to);			break;		}	}	if(n < 0) 		fprint(2, "cp: error reading %s: %r\n", from);	free(buf);}