#265: Failure when fetching a file with wget
-------------------------+--------------------------------------------------
Reporter: toots | Owner: admin
Type: Bugs | Status: new
Priority: 8 | Milestone: NEAR FUTURE
Component: Liquidsoap | Version: 0.9.0+svn
Resolution: | Keywords:
Mac: 1 | Linux: 1
Netbsd: 1 | Other: 1
Freebsd: 1 |
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Comment(by toots):
Ok, it kept on crashing here, so I took some time to try to fix this.
Unfortunately, I don't understand anything on the initial code:
{{{
(* We create a fresh stdin for the process,
* and another one, unused by the child, on which we'll wait for EOF
* as a mean to detect termination. *)
let (iR,iW) = Unix.pipe () in
let (xR,xW) = Unix.pipe () in
let pid =
Unix.create_process
program (command program s local)
iR Unix.stderr Unix.stderr
in
dlog#f 4 "Executing %s %S %S" program s local ;
let timeout = max 0. (maxtime -. Unix.gettimeofday ()) in
Unix.close iR ;
Unix.close xW ;
if Unix.select [xR] [] [] timeout = ([],[],[]) then
Unix.kill pid 9 ;
let (p,code) = Unix.waitpid [] pid in
assert (p <> 0) ;
dlog#f 4 "Download process finished (%s)"
(match code with
| Unix.WSIGNALED _ -> "killed"
| Unix.WEXITED 0 -> "ok"
| _ -> "error") ;
Unix.close iW ;
Unix.close xR ;
}}}
In particular, I don't understand why the {{{Unix.select}}} will wake up
when the process has finished..
I have rewritten this using the same technique as I used for the external
encoders:
{{{
let proc =
try
Unix.open_process_in (command program s local)
with
| _ -> assert false
in
let xR = Unix.descr_of_in_channel proc in
dlog#f 4 "Executing %s %S %S" program s local ;
let rec wait_timeout () =
let timeout = max 0. (maxtime -. Unix.gettimeofday ()) in
let (x,_,_) = Unix.select [xR] [] [] timeout in
if List.mem xR x then
begin
if input proc tmpbuf 0 1024 > 0 then
wait_timeout ()
else
begin
dlog#f 4 "Process %s %S %S exited." program s local ;
Unix.close_process_in proc
end
end
else
begin
dlog#f 4 "Timeout expired: killing process %s %S %S" program s
local ;
Unix.close_process_in proc
end
in
begin
try
let code = wait_timeout () in
dlog#f 4 "Download process finished (%s)"
(match code with
| Unix.WSIGNALED _ -> "killed"
| Unix.WEXITED 0 -> "ok"
| _ -> "error") ;
}}}
Such an implementation seems much more correct to me. What do you think ?
It is in production on radiopi, so I should catch any error in this piece
of code..
Corresponding patch attached.
--
Ticket URL: <http://savonet.rastageeks.org/ticket/265#comment:1>
Savonet <http://savonet.rastageeks.org/>
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