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|
implement Virgild;
include "sys.m";
sys: Sys;
include "draw.m";
include "ip.m";
Virgild: module
{
init: fn(ctxt: ref Draw->Context, argv: list of string);
};
stderr: ref Sys->FD;
Udphdrsize: con IP->Udphdrlen;
init(nil: ref Draw->Context, nil: list of string)
{
sys = load Sys Sys->PATH;
stderr = sys->fildes(2);
sys->pctl(Sys->FORKNS|Sys->FORKFD, nil);
if(sys->chdir("/lib/ndb") < 0){
sys->fprint(stderr, "virgild: no database\n");
return;
}
for(;;sys->sleep(10*1000)){
fd := openlisten();
if(fd == nil)
return;
buf := array[512] of byte;
for(;;){
n := sys->read(fd, buf, len buf);
if(n <= Udphdrsize){
break;
}
if(n <= Udphdrsize+1)
continue;
# dump any cruft after the question
for(i := Udphdrsize; i < n; i++){
c := int buf[i];
if(c == ' ' || c == 0 || c == '\n')
break;
}
answer := query(string buf[Udphdrsize:i]);
if(answer == nil)
continue;
# reply
r := array of byte answer;
if(len r > len buf - Udphdrsize)
continue;
buf[Udphdrsize:] = r;
sys->write(fd, buf, Udphdrsize+len r);
}
fd = nil;
}
}
openlisten(): ref Sys->FD
{
(ok, c) := sys->announce("udp!*!virgil");
if(ok < 0){
sys->fprint(stderr, "virgild: can't open port: %r\n");
return nil;
}
if(sys->fprint(c.cfd, "headers") <= 0){
sys->fprint(stderr, "virgild: can't set headers: %r\n");
return nil;
}
c.dfd = sys->open(c.dir+"/data", Sys->ORDWR);
if(c.dfd == nil) {
sys->fprint(stderr, "virgild: can't open data file\n");
return nil;
}
return c.dfd;
}
#
# query is userid?question
#
# for now, we're ignoring userid
#
query(request: string): string
{
(n, l) := sys->tokenize(request, "?");
if(n < 2){
sys->fprint(stderr, "virgild: bad request %s %d\n", request, n);
return nil;
}
#
# until we have something better, ask cs
# to translate, make the request look cs-like
#
fd := sys->open("/net/cs", Sys->ORDWR);
if(fd == nil){
sys->fprint(stderr, "virgild: can't open /net/cs - %r\n");
return nil;
}
q := array of byte ("tcp!" + hd(tl l) + "!1000");
if(sys->write(fd, q, len q) < 0){
sys->fprint(stderr, "virgild: can't write /net/cs - %r: %s\n", string q);
return nil;
}
sys->seek(fd, big 0, 0);
buf := array[512-Udphdrsize-len request-1] of byte;
n = sys->read(fd, buf, len buf);
if(n <= 0){
sys->fprint(stderr, "virgild: can't read /net/cs - %r\n");
return nil;
}
(nil, l) = sys->tokenize(string buf[0:n], " \t");
(nil, l) = sys->tokenize(hd(tl l), "!");
return request + "=" + hd l;
}
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