Malcolm Matalka <malc...@terrateam.io> writes:
> Hello, I'm debugging a bug in my program using the multi interface. I'm
> still trying to work out some details but I thought maybe someone who knows
> the codebase better than I might just see it as obvious.
>
> In my case, I am setting SOCKETFUNCTION, TIMERFUNCTION, and
> CLOSESOCKETFUNCTION
> because I need to manage the sockets myself (I'm integrating curl against a
> concurrency library in Ocaml). Because of how the concurrency library works,
> instead of doing any work in those callbacks functions, I'm adding the event
> to
> a queue then processing the events after a "perform" or "action" call.
>
> What I'm seeing is that I have a POLL_REMOVE call for a socket, but then my
> CLOSESOCKETFUNCTION callback is not being called. I can see in the ktrace
> logs that the socket is directly being closed with "close".
>
> I *think* this is happening due libcurl deciding the connection has timed out
> and some logic chooses not to execute the close callback. But I'm not
> entirely sure.
>
> Any idea how I can turn on the tracing for cf-socket.c? I have set the
> global trace to 'all' but I am not seeing the logs I am looking for?
>
> I am on FreeBSD use curl 8.11.1.
>
> Thank you
>
> /Malcolm
After learning some lldb, this is what I got. Here is the log from my
application (I log on timerfunction, socketfunction, and closefunction). Lines
starting with '#' are my annotations to expalin
# We receive timeout for 1 ms
timeout_function : 1
still_running : 1
firing timeout
timeout
# We receive sockketfunction call for poll_in on fd 5. This adds the event to
our queue
socket_function : poll_in : 5
# Setup new timeout
timeout_function : 2
# execute a perform
perform
still_running : 1
# This is the queue handler processing the queue
socket : poll_in : 5
# Async wait on 5
wait fd : 5
# we've timed out
firing timeout
timeout
timeout_function : 1
perform
still_running : 1
firing timeout
timeout
# update timeout
timeout_function : 8
perform
timeout_function : 8
still_running : 1
# Fire timeout
firing timeout
timeout
# We see now poll_remove for fd 5, this adds handling the poll_remove to the
queue
socket_function : poll_remove : 5
Now, I would expect to see a "close_function" message here as we get a close,
however we do not. I added a breakpoint in lldb to print the backgroud out on
any call to close and I can see that libcurl is calling close right after the
poll_remove.
* frame #0: 0x00000008257d23c8 libc.so.7`close(fd=5) at close.c:43:10
frame #1: 0x00000008231fda0a
libcurl.so.4`destroy_async_data(async=0x00001c8252225620) at asyn-thread.c:433:5
frame #2: 0x00000008231fdbca
libcurl.so.4`Curl_resolver_is_resolved(data=0x00001c8252224800,
entry=0x0000000820e163f8) at asyn-thread.c:612:5
frame #3: 0x0000000823229205
libcurl.so.4`Curl_resolv_check(data=0x00001c8252224800, dns=0x0000000820e163f8)
at hostip.c:1409:12
frame #4: 0x000000082324be96 libcurl.so.4`multi_runsingle [inlined]
state_resolving(multi=0x00001c82521e5000, data=0x00001c8252224800,
stream_errorp=0x0000000820e163eb, resultp=0x0000000820e163f0) at
multi.c:2502:14
frame #5: 0x000000082324be8a
libcurl.so.4`multi_runsingle(multi=0x00001c82521e5000, nowp=0x0000000820e164f8,
data=0x00001c8252224800) at multi.c:2681:12
frame #6: 0x000000082324f3f8
libcurl.so.4`multi_run_expired(mrc=0x0000000820e164f0) at multi.c:3510:14
frame #7: 0x000000082324d9f2
libcurl.so.4`multi_socket(multi=0x00001c82521e5000, checkall=<unavailable>,
s=<unavailable>, ev_bitmask=<unavailable>, running_handles=0x0000000820e16604)
at multi.c:3601:
12
frame #8: 0x000000082324db6c
libcurl.so.4`curl_multi_socket_action(m=<unavailable>, s=<unavailable>,
ev_bitmask=<unavailable>, running_handles=<unavailable>) at multi.c:3727:10
[artificial]
frame #9: 0x0000000000424af0
abb_curl_cli.native`caml_curl_multi_socket_action(v_multi=35172246200, v_fd=1,
v_kind=1) at curl-helper.c:4981:10
Also, I do feel confident that the CLOSEFUNCTION behaviour does work because I
see it working in other contexts.
If I understand what is happening here correctly, I believe this block of code
should not call "wakeup_close" (which is defined as "close" in my environment)
but instead should check if the close callback is defined and call that instead.
https://github.com/curl/curl/blob/curl-8_11_1/lib/asyn-thread.c#L426-L431
Is that correct?
Thank you
--
Malcolm Matalka
Terrateam
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