ref: 670f4e90ee6028ffee399e5a96fb5e4cd72fc7bc
dir: /appl/lib/dial.b/
implement Dial;
include "sys.m";
sys: Sys;
include "dial.m";
#
# the dialstring is of the form '[/net/]proto!dest'
#
dial(addr: string, local: string): ref Connection
{
if(sys == nil)
sys = load Sys Sys->PATH;
(netdir, proto, rem) := dialparse(addr);
if(netdir != nil)
return csdial(netdir, proto, rem, local);
c := csdial("/net", proto, rem, local);
if(c != nil)
return c;
err := sys->sprint("%r");
if(lookstr(err, "refused") >= 0)
return nil;
c = csdial("/net.alt", proto, rem, local);
if(c != nil)
return c;
# ignore the least precise one
alterr := sys->sprint("%r");
if(lookstr(alterr, "translate")>=0 || lookstr(alterr, "does not exist")>=0)
sys->werrstr(err);
else
sys->werrstr(alterr);
return nil;
}
#
# ask the connection server to translate
#
csdial(netdir: string, proto: string, rem: string, local: string): ref Connection
{
fd := sys->open(netdir+"/cs", Sys->ORDWR);
if(fd == nil){
# no connection server, don't translate
return call(netdir+"/"+proto+"/clone", rem, local);
}
if(sys->fprint(fd, "%s!%s", proto, rem) < 0)
return nil;
# try each recipe until we get one that works
besterr, err: string;
sys->seek(fd, big 0, 0);
for(;;){
(clonefile, addr) := csread(fd);
if(clonefile == nil)
break;
c := call(redir(clonefile, netdir), addr, local);
if(c != nil)
return c;
err = sys->sprint("%r");
if(lookstr(err, "does not exist") < 0)
besterr = err;
}
if(besterr != nil)
sys->werrstr(besterr);
else
sys->werrstr(err);
return nil;
}
call(clonefile: string, dest: string, local: string): ref Connection
{
(cfd, convdir) := clone(clonefile);
if(cfd == nil)
return nil;
if(local != nil)
rv := sys->fprint(cfd, "connect %s %s", dest, local);
else
rv = sys->fprint(cfd, "connect %s", dest);
if(rv < 0)
return nil;
fd := sys->open(convdir+"/data", Sys->ORDWR);
if(fd == nil)
return nil;
return ref Connection(fd, cfd, convdir);
}
clone(clonefile: string): (ref Sys->FD, string)
{
pdir := parent(clonefile);
if(pdir == nil){
sys->werrstr(sys->sprint("bad clone file name: %q", clonefile));
return (nil, nil);
}
cfd := sys->open(clonefile, Sys->ORDWR);
if(cfd == nil)
return (nil, nil);
lno := readchan(cfd);
if(lno == nil)
return (nil, nil);
return (cfd, pdir+"/"+lno);
}
readchan(cfd: ref Sys->FD): string
{
buf := array[Sys->NAMEMAX] of byte;
n := sys->read(cfd, buf, len buf);
if(n < 0)
return nil;
if(n == 0){
sys->werrstr("empty clone file");
return nil;
}
return string int string buf[0: n];
}
redir(old: string, newdir: string): string
{
# because cs is in a different name space, replace the mount point
# assumes the mount point is directory in root (eg, /net/proto/clone)
if(len old > 1 && old[0] == '/'){
p := lookc(old[1:], '/');
if(p >= 0)
return newdir+"/"+old[1+p+1:];
}
return newdir+"/"+old;
}
lookc(s: string, c: int): int
{
for(i := 0; i < len s; i++)
if(s[i] == c)
return i;
return -1;
}
backc(s: string, i: int, c: int): int
{
if(i >= len s)
return -1;
while(i >= 0 && s[i] != c)
i--;
return i;
}
lookstr(s: string, t: string): int
{
lt := len t; # we know it's not zero
Search:
for(i := 0; i <= len s - lt; i++){
for(j := 0; j < lt; j++)
if(s[i+j] != t[j])
continue Search;
return i;
}
return -1;
}
#
# [[/netdir/]proto!]remainder
#
dialparse(addr: string): (string, string, string)
{
p := lookc(addr, '!');
if(p < 0)
return (nil, "net", addr);
if(addr[0] != '/' && addr[0] != '#')
return (nil, addr[0: p], addr[p+1:]);
p2 := backc(addr, p, '/');
if(p2 <= 0)
return (addr[0: p], "net", addr[p+1:]); # plan 9 returns proto ""
return (addr[0: p2], addr[p2+1: p], addr[p+1:]);
}
#
# announce a network service
#
announce(addr: string): ref Connection
{
if(sys == nil)
sys = load Sys Sys->PATH;
(naddr, clonefile) := nettrans(addr);
if(naddr == nil)
return nil;
(ctl, convdir) := clone(clonefile);
if(ctl == nil){
sys->werrstr(sys->sprint("announce %r"));
return nil;
}
if(sys->fprint(ctl, "announce %s", naddr) < 0){
sys->werrstr(sys->sprint("announce writing %s: %r", clonefile));
return nil;
}
return ref Connection(nil, ctl, convdir);
}
#
# listen for an incoming call on announced connection
#
listen(ac: ref Connection): ref Connection
{
if(sys == nil)
sys = load Sys Sys->PATH;
pdir := parent(ac.dir); # ac.dir should be /netdir/N
if(pdir == nil){
sys->werrstr(sys->sprint("listen directory format: %q", ac.dir));
return nil;
}
ctl := sys->open(ac.dir+"/listen", Sys->ORDWR);
if(ctl == nil){
sys->werrstr(sys->sprint("listen opening %s: %r", ac.dir+"/listen"));
return nil;
}
lno := readchan(ctl);
if(lno == nil){
sys->werrstr(sys->sprint("listen reading %s/listen: %r", ac.dir));
return nil;
}
return ref Connection(nil, ctl, pdir+"/"+lno);
}
#
# translate an address [[/netdir/]proto!rem] using /netdir/cs
# returning (newaddress, clonefile)
#
nettrans(addr: string): (string, string)
{
(netdir, proto, rem) := dialparse(addr);
if(proto == nil || proto == "net"){
sys->werrstr(sys->sprint("bad dial string: %s", addr));
return (nil, nil);
}
if(netdir == nil)
netdir = "/net";
# try to translate using connection server
fd := sys->open(netdir+"/cs", Sys->ORDWR);
if(fd == nil){
# use it untranslated
if(rem == nil){
sys->werrstr(sys->sprint("bad dial string: %s", addr));
return (nil, nil);
}
return (rem, netdir+"/"+proto+"/clone");
}
if(sys->fprint(fd, "%s!%s", proto, rem) < 0)
return (nil, nil);
sys->seek(fd, big 0, 0);
(clonefile, naddr) := csread(fd);
if(clonefile == nil)
return (nil, nil);
return (naddr, redir(clonefile, netdir));
}
csread(fd: ref Sys->FD): (string, string)
{
buf := array[Sys->NAMEMAX] of byte;
n := sys->read(fd, buf, len buf);
if(n < 0)
return (nil, nil);
line := string buf[0: n];
p := lookc(line, ' ');
if(p < 0)
return (nil, nil);
if(p == 0){
sys->werrstr("cs: no translation");
return (nil, nil);
}
return (line[0:p], line[p+1:]);
}
#
# accept a call, return an fd to the open data file
#
accept(c: ref Connection): ref Sys->FD
{
if(sys == nil)
sys = load Sys Sys->PATH;
sys->fprint(c.cfd, "accept %s", lastname(c.dir)); # ignore return value, network might not need accepts
return sys->open(c.dir+"/data", Sys->ORDWR);
}
#
# reject a call, tell device the reason for the rejection
#
reject(c: ref Connection, why: string): int
{
if(sys == nil)
sys = load Sys Sys->PATH;
if(sys->fprint(c.cfd, "reject %s %q", lastname(c.dir), why) < 0)
return -1;
return 0;
}
lastname(dir: string): string
{
p := backc(dir, len dir-1, '/');
if(p < 0)
return dir;
return dir[p+1:]; # N in /net/N
}
parent(dir: string): string
{
p := backc(dir, len dir-1, '/');
if(p < 0)
return nil;
return dir[0: p];
}
netmkaddr(addr, net, svc: string): string
{
if(sys == nil)
sys = load Sys Sys->PATH;
if(net == nil)
net = "net";
(n, nil) := sys->tokenize(addr, "!");
if(n <= 1){
if(svc== nil)
return sys->sprint("%s!%s", net, addr);
return sys->sprint("%s!%s!%s", net, addr, svc);
}
if(svc == nil || n > 2)
return addr;
return sys->sprint("%s!%s", addr, svc);
}
netinfo(c: ref Connection): ref Conninfo
{
if(sys == nil)
sys = load Sys Sys->PATH;
if((dir := c.dir) == nil){
if(c.dfd == nil)
return nil;
dir = parent(sys->fd2path(c.dfd));
if(dir == nil)
return nil;
}
ci := ref Conninfo;
ci.dir = dir;
ci.root = parent(dir);
while((p := parent(ci.root)) != nil && p != "/")
ci.root = p;
(ok, d) := sys->stat(ci.dir);
if(ok >= 0)
ci.spec = sys->sprint("#%c%d", d.dtype, d.dev);
(ci.lsys, ci.lserv) = getendpoint(ci.dir, "local");
(ci.rsys, ci.rserv) = getendpoint(ci.dir, "remote");
p = parent(ci.dir);
if(p == nil)
return nil;
if(len p >= 5 && p[0:5] == "/net/")
p = p[5:];
ci.laddr = sys->sprint("%s!%s!%s", p, ci.lsys, ci.lserv);
ci.raddr = sys->sprint("%s!%s!%s", p, ci.rsys, ci.rserv);
return ci;
}
getendpoint(dir: string, file: string): (string, string)
{
fd := sys->open(dir+"/"+file, Sys->OREAD);
buf := array[128] of byte;
if(fd == nil || (n := sys->read(fd, buf, len buf)) <= 0)
return ("???", "???"); # compatible, but probably poor defaults
if(n > 0 && buf[n-1] == byte '\n')
n--;
s := string buf[0: n];
p := lookc(s, '!');
if(p < 0)
return (s, "???");
return (s[0:p], s[p+1:]);
}