implement Virgil; include "sys.m"; include "string.m"; include "keyring.m"; include "draw.m"; include "security.m"; sys: Sys; stderr: ref Sys->FD; done: int; Udphdrsize: con 12; # # this module is very udp dependent. it shouldn't be. -- presotto # Call with first element of argv an arbitrary string, which is # discarded here. argv must also contain at least a question. # virgil(argv: list of string): string { s,question,reply,r : string; addr : list of string; noctet, timerpid, readerpid: int; if (argv == nil || tl argv == nil || hd (tl argv) == nil) return nil; done = 0; str := load String "/dis/lib/string.dis"; sys = load Sys Sys->PATH; stderr = sys->fildes(2); # We preserve the convention that the first arg is not an option. # Undocumented '-v address' option allows passing in address # of virgild, circumventing broadcast. Used for development, # to avoid pestering servers on network. argv = tl argv; s = hd argv; if(s[0] == '-') { if(s[1] != 'v') return nil; argv = tl argv; if (argv == nil) return nil; s = hd argv; (noctet, addr) = sys->tokenize(s, "."); if (noctet != 4) return nil; argv = tl argv; } # Is there a question? if (argv == nil) return nil; question = hd argv; (ok, c) := sys->announce("udp!*!0"); if(ok < 0) return nil; if(sys->fprint(c.cfd, "headers4") < 0) return nil; c.dfd = sys->open(c.dir+"/data", sys->ORDWR); if(c.dfd == nil) return nil; readerchan := chan of string; timerchan := chan of int; readerpidchan := chan of int; spawn timer(timerchan); timerpid = <-timerchan; spawn reader(c.dfd, readerchan, readerpidchan); readerpid = <-readerpidchan; buf := array[1000] of byte; question = getid() + "?" + question; qbuf := array of byte question; buf[Udphdrsize:] = qbuf; if (addr != nil) { for (bdx := 0; bdx < noctet; bdx++) { buf[bdx] = byte hd addr; addr = tl addr; } } else { buf[0] = byte 255; buf[1] = byte 255; buf[2] = byte 255; buf[3] = byte 255; } buf[8] = byte (2202>>8); buf[9] = byte (2202 & 16rFF); for(tries := 0; tries < 5; ){ if(sys->write(c.dfd, buf, Udphdrsize + len qbuf) < 0) break; alt { r = <-readerchan => ; <-timerchan => tries++; continue; }; if(str->prefix(question + "=", r)){ reply = r[len question + 1:]; break; } } done = 1; killpid(readerpid); killpid(timerpid); return reply; } getid(): string { fd := sys->open("/dev/sysname", sys->OREAD); if(fd == nil) return "unknown"; buf := array[256] of byte; n := sys->read(fd, buf, len buf); if(n < 1) return "unknown"; return string buf[0:n]; } reader(fd: ref sys->FD, cstring: chan of string, cpid: chan of int) { pid := sys->pctl(0, nil); cpid <-= pid; buf := array[2048] of byte; n := sys->read(fd, buf, len buf); if(n <= Udphdrsize) return; # dump cruft for(i := Udphdrsize; i < n; i++) if((int buf[i]) == 0) break; if(!done) cstring <-= string buf[Udphdrsize:i]; } timer(c: chan of int) { pid := sys->pctl(0, nil); c <-= pid; while(!done){ sys->sleep(1000); if(done) break; c <-= 1; } } killpid(pid: int) { fd := sys->open("#p/"+(string pid)+"/ctl", sys->OWRITE); if(fd == nil) return; sys->write(fd, array of byte "kill", 4); }