GNU bug report logs - #6074
accept-process-output on listening sockets cause non-interruptible infloop

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Message #14 received at 6074 <at> debbugs.gnu.org (full text, mbox):

From: Pip Cet <pipcet <at> gmail.com>
To: 6074 <at> debbugs.gnu.org
Subject: accept-process-output on listening sockets cause non-interruptible
 infloop
Date: Mon, 22 Jul 2019 03:52:33 +0000

[Message part 1 (text/plain, inline)]

> With this code Emacs seems to be stuck in an endless loop and is not
> incorruptible with C-g:

> (let ((proc (make-network-process :name "foo" :server t :noquery t
>  :family 'local :service "/tmp/foo.socket")))
>   (accept-process-output proc))

On Linux, the problem appears to be that we don't abort this infloop
in process.c if a read () returns EINVAL:

          while (true)
        {
          int nread = read_process_output (proc, wait_proc->infd);
          if (nread < 0)
            {
              if (errno == EIO || would_block (errno))
            break;
            }
          else
            {
              if (got_some_output < nread)
            got_some_output = nread;
              if (nread == 0)
            break;
              read_some_bytes = true;
            }
        }

That seems problematic to me, since we might get non-EIO errors for
other reasons. I'm attaching a patch that appears to fix the issue.

[0001-Don-t-retry-reading-after-receiving-EINVAL-bug-6074.patch (text/x-patch, attachment)]

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