implement Keyset; include "sys.m";	sys: Sys;include "keyring.m";	keyring: Keyring;include "daytime.m";	daytime: Daytime;include "readdir.m"; include "keyset.m"; PKHASHLEN: con Keyring->SHA1dlen * 2; init(): string{	sys = load Sys Sys->PATH;	keyring = load Keyring Keyring->PATH;	if(keyring == nil)		return cant(Keyring->PATH);	daytime = load Daytime Daytime->PATH;	if(daytime == nil)		return cant(Daytime->PATH);	return nil;} cant(s: string): string{	return sys->sprint("can't load %s: %r", s);} pkhash(pk: string): string{	d := array of byte pk;	digest := array[Keyring->SHA1dlen] of byte;	keyring->sha1(d, len d, digest, nil);	s := "";	for(i := 0; i < len digest; i++)		s += sys->sprint("%2.2ux", int digest[i]);	return s;} keysforsigner(signername: string, spkhash: string, user: string, dir: string): (list of (string, string, string), string){	if(spkhash != nil && len spkhash != PKHASHLEN)		return (nil, "invalid hash string");	if(dir == nil){		if(user == nil)			user = readname("/dev/user");		if(user == nil)			dir = "/lib/keyring";		else			dir = "/usr/" + user + "/keyring";	}	readdir := load Readdir Readdir->PATH;	if(readdir == nil)		return (nil, sys->sprint("can't load Readdir: %r"));	now := daytime->now();	(a, ok) := readdir->init(dir, Readdir->COMPACT|Readdir->MTIME);	if(ok < 0)		return (nil, sys->sprint("can't open %s: %r", dir));	keys: list of (string, string, string);	for(i := 0; i < len a; i++){		if(a[i].mode & Sys->DMDIR)			continue;		f := dir + "/" + a[i].name;		info := keyring->readauthinfo(f);		if(info == nil || info.cert == nil || info.cert.exp != 0 && info.cert.exp < now)			continue;		if(signername != nil && info.cert.signer != signername)			continue;		if(spkhash != nil && pkhash(keyring->pktostr(info.spk)) != spkhash)			continue;		keys = (f, info.mypk.owner, info.cert.signer) :: keys;	}	return (keys, nil);} readname(f: string): string{	fd := sys->open(f, Sys->OREAD);	if(fd == nil)		return nil;	buf := array[Sys->NAMEMAX] of byte;	n := sys->read(fd, buf, len buf);	if(n <= 0)		return nil;	return string buf[0:n];}