implement Msgio; # probably need Authio or Auth instead, to include Authinfo, Certificate and signing operations?# eliminates certificates and sigalgs from Keyring# might be better just to have mp.m and sec.m?# general signature module?# Keyring->dhparams is is only needed by createsignerkey (and others creating Authinfo)# should also improve pkcs include "sys.m";	sys: Sys; include "keyring.m"; include "msgio.m"; init(){	sys = load Sys Sys->PATH;} seterr(r: int){	if(r > 0)		sys->werrstr("input or format error");	else if(r == 0)		sys->werrstr("hungup");} ## i/o on a channel that might or might not retain record boundaries#getmsg(fd: ref Sys->FD): array of byte{	num := array[5] of byte;	r := sys->readn(fd, num, len num);	if(r != len num) {		seterr(r);		return nil;	}	h := string num;	if(h[0] == '!')		m := int h[1:];	else		m = int h;	if(m < 0 || m > Maxmsg) {		seterr(1);		return nil;	}	buf := array[m] of byte;	r = sys->readn(fd, buf, m);	if(r != m){		seterr(r);		return nil;	}	if(h[0] == '!'){		sys->werrstr(string buf);		return nil;	}	return buf;} sendmsg(fd: ref Sys->FD, buf: array of byte, n: int): int{	if(sys->fprint(fd, "%4.4d\n", n) < 0)		return -1;	return sys->write(fd, buf, n);} senderrmsg(fd: ref Sys->FD, s: string): int{	buf := array of byte s;	if(sys->fprint(fd, "!%3.3d\n", len buf) < 0)		return -1;	if(sys->write(fd, buf, len buf) <= 0)		return -1;	return 0;} ## i/o on a delimited channel#getbuf(fd: ref Sys->FD, buf: array of byte, n: int): (int, string){	n = sys->read(fd, buf, n);	if(n <= 0){		seterr(n);		return (-1, sys->sprint("%r"));	}	if(buf[0] == byte 0)		return (n, nil);	if(buf[0] != byte 16rFF){		# garbled, possibly the wrong encryption		return (-1, "failure");	}	# error string	if(--n < 1)		return (-1, "unknown");	return (-1, string buf[1:]);} getbytearray(fd: ref Sys->FD): (array of byte, string){	buf := array[Maxmsg] of byte;	(n, err) := getbuf(fd, buf, len buf);	if(n < 0)		return (nil, err);	return (buf[1: n], nil);} getstring(fd: ref Sys->FD): (string, string){	(a, err) := getbytearray(fd);	if(a != nil)		return (string a, err);	return (nil, err);} putbuf(fd: ref Sys->FD, data: array of byte, n: int): int{	buf := array[Maxmsg] of byte;	if(n < 0) {		buf[0] = byte 16rFF;		n = -n;	}else		buf[0] = byte 0;	if(n >= Maxmsg)		n = Maxmsg-1;	buf[1:] = data;	return sys->write(fd, buf, n+1);} putstring(fd: ref Sys->FD, s: string): int{	a := array of byte s;	return putbuf(fd, a, len a);} putbytearray(fd: ref Sys->FD, a: array of byte, n: int): int{	if(n > len a)		n = len a;	return putbuf(fd, a, n);} puterror(fd: ref Sys->FD, s: string): int{	if(s == nil)		s = "unknown";	a := array of byte s;	return putbuf(fd, a, -len a);}