#include <u.h>#include <libc.h> #define	DEFB	(8*1024) 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; 	if(argc<3){		fprint(2, "usage:\tcp fromfile tofile\n");		fprint(2, "\tcp fromfile ... todir\n");		exits("usage");	}	todir=0;	if(dirstat(argv[argc-1], &dirb)==0 && (dirb.mode&CHDIR))		todir=1;	if(argc>3 && !todir){		fprint(2, "cp: %s not a directory\n", argv[argc-1]);		exits("bad usage");	}	for(i=1; i<argc-1; i++)		copy(argv[i], argv[argc-1], todir);	exits(0);} voidcopy(char *from, char *to, int todir){	Dir dirb, dirt;	char name[256];	int fdf, fdt; 	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(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);}