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implement Tftp;
include "sys.m";
sys: Sys;
include "tftp.m";
Maxretry: con 5; # retries per block
Maxblock: con 512; # protocol's usual maximum data block size
Tftphdrlen: con 4;
Read, Write, Data, Ack, Error: con 1+iota; # tftp opcode
progress: int;
put2(buf: array of byte, o: int, val: int)
{
buf[o] = byte (val >> 8);
buf[o+1] = byte val;
}
get2(buf: array of byte, o: int): int
{
return (int buf[o] << 8) | int buf[o+1];
}
kill(pid: int)
{
fd := sys->open("#p/" + string pid + "/ctl", sys->OWRITE);
if(fd == nil)
return;
msg := array of byte "kill";
sys->write(fd, msg, len msg);
}
timeoutproc(c: chan of int, howlong: int)
{
c <-= sys->pctl(0, nil);
sys->sleep(howlong);
c <-= 1;
}
tpid := -1;
timeoutcancel()
{
if(tpid >= 0) {
kill(tpid);
tpid = -1;
}
}
timeoutstart(howlong: int): chan of int
{
timeoutcancel();
tc := chan of int;
spawn timeoutproc(tc, howlong);
tpid = <-tc;
return tc;
}
init(p: int)
{
sys = load Sys Sys->PATH;
progress = p;
}
reader(pidc: chan of int, fd: ref Sys->FD, bc: chan of array of byte)
{
pid := sys->pctl(0, nil);
pidc <-= pid;
buf := array[Tftphdrlen + Maxblock] of byte;
for(;;){
n := sys->read(fd, buf, len buf);
bc <-= buf[0 : n];
}
}
receive(host: string, filename: string, fd: ref Sys->FD): string
{
rbuf: array of byte;
(ok, conn) := sys->dial("udp!" + host + "!69", nil);
if(ok < 0)
return sys->sprint("can't dial %s: %r", host);
buf := array[Tftphdrlen + Maxblock] of byte;
i := 0;
put2(buf, i, Read);
i += 2;
a := array of byte filename;
buf[i:] = a;
i += len a;
buf[i++] = byte 0;
mode := array of byte "binary";
buf[i:] = mode;
i += len mode;
buf[i++] = byte 0;
pidc := chan of int;
bc := chan of array of byte;
spawn reader(pidc, conn.dfd, bc);
tftppid := <-pidc;
lastblock := 0;
for(;;) {
Retry:
for(count := 0;; count++) {
if(count >= Maxretry){
kill(tftppid);
return sys->sprint("tftp timeout");
}
# (re)send request/ack
if(sys->write(conn.dfd, buf, i) < 0) {
kill(tftppid);
return sys->sprint( "error writing %s/data: %r", conn.dir);
}
# wait for next block
mtc := timeoutstart(3000);
for(;;){
alt {
<-mtc =>
if(progress)
sys->print("T");
continue Retry;
rbuf = <-bc =>
if(len rbuf < Tftphdrlen)
break;
op := get2(rbuf, 0);
case op {
Data =>
block := get2(rbuf, 2);
if(block == lastblock + 1) {
timeoutcancel();
break Retry;
}else if(progress)
sys->print("S");
Error =>
timeoutcancel();
kill(tftppid);
return sys->sprint("server error %d: %s", get2(rbuf, 2), string rbuf[4:]);
* =>
timeoutcancel();
kill(tftppid);
return sys->sprint("phase error op=%d", op);
}
}
}
}
n := len rbuf;
# copy the data somewhere
if(sys->write(fd, rbuf[Tftphdrlen:], n - Tftphdrlen) < 0) {
kill(tftppid);
return sys->sprint("writing destination: %r");
}
lastblock++;
if(progress && lastblock % 25 == 0)
sys->print(".");
if(n < Maxblock + Tftphdrlen) {
if(progress)
sys->print("\n");
break;
}
# send an ack
put2(buf, 0, Ack);
put2(buf, 2, lastblock);
}
kill(tftppid);
return nil;
}
|
