implement Cp; include "sys.m";	sys: Sys; include "draw.m";include "arg.m"; include "readdir.m";	readdir: Readdir; Cp: module{	init:	fn(nil: ref Draw->Context, args: list of string);}; stderr: ref Sys->FD;errors := 0;gflag := 0;uflag := 0;xflag := 0; init(nil: ref Draw->Context, args: list of string){	sys = load Sys Sys->PATH;	stderr = sys->fildes(2); 	arg := load Arg Arg->PATH;	recursive := 0;	arg->init(args);	arg->setusage("\tcp [-gux] src target\n\tcp [-r] [-gux] src ... directory");	while((opt := arg->opt()) != 0)		case opt {		'r' =>	recursive = 1;		'g' => gflag = 1;		'u' => uflag = gflag = 1;		'x' => xflag = 1;		* =>	arg->usage();		}	args = arg->argv();	argc := len args;	if(argc < 2)		arg->usage();	arg = nil; 	dst: string;	for(t := args; t != nil; t = tl t)		dst = hd t; 	(ok, dir) := sys->stat(dst);	todir := (ok != -1 && (dir.mode & Sys->DMDIR));	if(argc > 2 && !todir){		sys->fprint(stderr, "cp: %s  not a directory\n", dst);		raise "fail:error";	}	if(recursive)		cpdir(args, dst);	else{		for(; tl args != nil; args = tl args){			if(todir)				cp(hd args, dst, basename(hd args));			else				cp(hd args, dst, nil);		}	}	if(errors)		raise "fail:error";} basename(s: string): string{	for((nil, ls) := sys->tokenize(s, "/"); ls != nil; ls = tl ls)		s = hd ls;	return s;} cp(src, dst: string, newname: string){	dd: Sys->Dir; 	if(newname != nil)		dst += "/" + newname;	(ok, ds) := sys->stat(src);	if(ok < 0){		warning(sys->sprint("%s: %r", src));		return;	}	if(ds.mode & Sys->DMDIR){		warning(src + " is a directory");		return;	}	(ok, dd) = sys->stat(dst);	if(ok != -1 && samefile(ds, dd)){		warning(src + " and " + dst + " are the same file");		return;	}	sfd := sys->open(src, Sys->OREAD);	if(sfd == nil){		warning(sys->sprint("cannot open %s: %r", src));		return;	}	dfd := sys->create(dst, Sys->OWRITE, ds.mode & 8r777);	if(dfd == nil){		warning(sys->sprint("cannot create %s: %r", dst));		return;	}	if(copy(sfd, dfd, src, dst)!=0)		return;	if(wstat(dfd, ds, 0) < 0)		warning(sys->sprint("can't wstat %s: %r", src));} copy(sfd, dfd: ref Sys->FD, src, dst: string): int{	buf := array[Sys->ATOMICIO] of byte;	while((r := sys->read(sfd, buf, len buf)) > 0){		if(sys->write(dfd, buf, r) != r){			warning(sys->sprint("error writing %s: %r", dst));			return -1;		}	}	if(r < 0){		warning(sys->sprint("error reading %s: %r", src));		return -1;	}	return 0;} cpdir(args: list of string, dst: string){	readdir = load Readdir Readdir->PATH;	if(readdir == nil){		sys->fprint(stderr, "cp: cannot load %s: %r\n", Readdir->PATH);		raise "fail:bad module";	}	cache = array[NCACHE] of list of ref Sys->Dir;	dexists := 0;	(ok, dd) := sys->stat(dst);	# destination file exists	if(ok != -1){		if((dd.mode & Sys->DMDIR) == 0){			warning(dst + ": destination not a directory");			return;		}		dexists = 1;	}	for(; tl args != nil; args = tl args){		ds: Sys->Dir;		src := hd args;		(ok, ds) = sys->stat(src);		if(ok < 0){			warning(sys->sprint("can't stat %s: %r", src));			continue;		}		if((ds.mode & Sys->DMDIR) == 0){			cp(hd args, dst, basename(hd args));		} else if(dexists){			if(samefile(ds, dd)){				warning("cannot copy " + src + " into itself");				continue;			}			copydir(src, dst + "/" + basename(src), ds);		} else			copydir(src, dst, ds);	}} copydir(src, dst: string, srcd: Sys->Dir){	(ok, nil) := sys->stat(dst);	if(ok != -1){		warning("cannot copy " + src + " onto another directory");		return;	}	tmode := srcd.mode | 8r777;	# Fix for Nt	dfd := sys->create(dst, Sys->OREAD, Sys->DMDIR | tmode);	if(dfd == nil){		warning(sys->sprint("cannot make directory %s: %r", dst));		return;	}	(entries, n) := readdir->init(src, Readdir->COMPACT);	for(i := 0; i < n; i++){		e := entries[i];		path := src + "/" + e.name;		if((e.mode & Sys->DMDIR) == 0)			cp(path, dst, e.name);		else if(seen(e))			warning(path + ": directory loop found");		else			copydir(path, dst + "/" + e.name, *e);	}	if(wstat(dfd, srcd, 1) < 0)		warning(sys->sprint("can't wstat %s: %r", dst));} wstat(dfd: ref Sys->FD, ds: Sys->Dir, mflag: int): int{	if(!xflag && !gflag && !uflag && !mflag)		return 0;	d := sys->nulldir;	if(xflag)		d.mtime = ds.mtime;	if(xflag || mflag)		d.mode = ds.mode;	if(uflag)		d.uid = ds.uid;	if(gflag)		d.gid = ds.gid;	return sys->fwstat(dfd, d);} samefile(d1: Sys->Dir, d2: Sys->Dir): int{	return d1.dtype == d2.dtype && d1.dev == d2.dev &&		d1.qid.qtype == d2.qid.qtype && d1.qid.path == d2.qid.path &&		d1.qid.vers == d2.qid.vers;} # Avoid loops in tangled namespaces. (from du.b)NCACHE: con 64; # must be power of twocache: array of list of ref sys->Dir; seen(dir: ref sys->Dir): int{	savlist := cache[int dir.qid.path&(NCACHE-1)];	for(c := savlist; c!=nil; c = tl c)		if(samefile(*dir, *hd c))			return 1;	cache[int dir.qid.path&(NCACHE-1)] = dir :: savlist;	return 0;} warning(e: string){	sys->fprint(stderr, "cp: %s\n", e);	errors++;}