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From: nmeum <>
Subject: [ISSUE] mpick: multi redir test hangs on Alpine
Date: Sat, 13 Mar 2021 20:27:37 +0100	[thread overview]
Message-ID: <> (raw)

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New issue by nmeum on mblaze repository

While trying to get the mblaze test suite running on Alpine Linux, I noticed that the `multi redir` test from `2000-mpick.t` does not terminate, even with current git HEAD. To reproduce:

$ cat /tmp/input
$ cat expr
let foo = from.addr == ""
let bar = from.disp == "Peter Example"
  foo |"sed ""s/^/1:&/""" && bar |"sed ""s/^/2:&/""" && skip
$ mpick -F ./expr < /tmp/input
<process does not terminate>

I debugged this a bit with `strace(1)`. The output of the 3 processes (mpick, sed, and sed) is available here:

* [sed.25493.txt](
* [sed.25494.txt](
* [sed.25495.txt](

I am a bit confused as to what is happening here. The mpick process (PID 25493) blocks because it waits for the first sed process (PID 25494) to terminate (since mpick uses `pclose(3)`). The sed process on the other hand doesn't terminate because it is still reading from the reading end of the pipe. However, I would expect that read to return with an EOF because the mpick process already closed the writing end of the pipe. Yet for some reason, it is stuck in a read system call. Maybe I am missing something obvious here, any idea what might be causing this?

             reply	other threads:[~2021-03-13 19:27 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-13 19:27 nmeum [this message]
2021-03-13 21:07 ` Duncaen
2021-03-13 21:08 ` Duncaen
2021-03-13 21:40 ` nmeum
2021-03-14 16:08 ` nmeum
2021-06-25 23:06 ` nmeum
2021-06-25 23:06 ` [ISSUE] [CLOSED] " nmeum
2021-06-25 23:06 ` nmeum

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