GNU bug report logs - #55153
29.0.50; Implement system_process_attributes on Cygwin

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Ken Brown <kbrown <at> cornell.edu>
To: bug-gnu-emacs <at> gnu.org
Subject: 29.0.50; Implement system_process_attributes on Cygwin
Date: Wed, 27 Apr 2022 11:00:05 -0400

I just noticed, as a result of the failure of 
desktop-tests--emacs-pid-running-p, that system_process_attributes was never 
implemented on Cygwin.  This turns out to be quite easy to do since most of the 
GNU/Linux code works without change on Cygwin.  I'll submit a patch in a 
follow-up email.

Ken

Message #8 received at 55153 <at> debbugs.gnu.org (full text, mbox):

From: Ken Brown <kbrown <at> cornell.edu>
To: 55153 <at> debbugs.gnu.org
Subject: Re: bug#55153: 29.0.50; Implement system_process_attributes on Cygwin
Date: Wed, 27 Apr 2022 11:16:46 -0400

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

On 4/27/2022 11:00 AM, Ken Brown wrote:
> I just noticed, as a result of the failure of 
> desktop-tests--emacs-pid-running-p, that system_process_attributes was never 
> implemented on Cygwin.  This turns out to be quite easy to do since most of the 
> GNU/Linux code works without change on Cygwin.  I'll submit a patch in a 
> follow-up email.

Patch attached.  It's written against the master branch, but it can easily be 
backported to the release branch.  It seems safe enough to me, but I don't have 
strong feelings about it.

Ken

[0001-Implement-system_process_attributes-on-Cygwin.patch (text/plain, attachment)]

Message #11 received at 55153 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Ken Brown <kbrown <at> cornell.edu>
Cc: 55153 <at> debbugs.gnu.org
Subject: Re: bug#55153: 29.0.50; Implement system_process_attributes on Cygwin
Date: Wed, 27 Apr 2022 18:52:58 +0300

> Date: Wed, 27 Apr 2022 11:16:46 -0400
> From: Ken Brown <kbrown <at> cornell.edu>
> 
> +# ifdef CYGWIN
> +  /* ttname */
> +  strcpy (procfn_end, "/ctty");
> +  fd = emacs_open (fn, O_RDONLY, 0);
> +  if (fd < 0)
> +    nread = 0;
> +  else
> +    {
> +      record_unwind_protect_int (close_file_unwind, fd);
> +      nread = emacs_read_quit (fd, procbuf, sizeof procbuf);
> +    }
> +  /* /proc/<pid>/ctty should always end in newline. */
> +  if (0 < nread && procbuf[nread - 1] == '\n')
> +    procbuf[nread - 1] = '\0';
> +  else
> +    procbuf[0] = '\0';
> +  attrs = Fcons (Fcons (Qttname, build_string (procbuf)), attrs);

Is what you read from /proc/<pid>/ctty guaranteed to be pure-ASCII
string?  If not, build_string is not the best idea here; you need to
produce a unibyte string and decode it.

Thanks.

P.S. Doesn't this warrant a NEWS entry?

Message #14 received at 55153 <at> debbugs.gnu.org (full text, mbox):

From: Ken Brown <kbrown <at> cornell.edu>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: 55153 <at> debbugs.gnu.org
Subject: Re: bug#55153: 29.0.50; Implement system_process_attributes on Cygwin
Date: Wed, 27 Apr 2022 12:45:45 -0400

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

On 4/27/2022 11:53 AM, Eli Zaretskii wrote:
>> Date: Wed, 27 Apr 2022 11:16:46 -0400
>> From: Ken Brown <kbrown <at> cornell.edu>
>>
>> +# ifdef CYGWIN
>> +  /* ttname */
>> +  strcpy (procfn_end, "/ctty");
>> +  fd = emacs_open (fn, O_RDONLY, 0);
>> +  if (fd < 0)
>> +    nread = 0;
>> +  else
>> +    {
>> +      record_unwind_protect_int (close_file_unwind, fd);
>> +      nread = emacs_read_quit (fd, procbuf, sizeof procbuf);
>> +    }
>> +  /* /proc/<pid>/ctty should always end in newline. */
>> +  if (0 < nread && procbuf[nread - 1] == '\n')
>> +    procbuf[nread - 1] = '\0';
>> +  else
>> +    procbuf[0] = '\0';
>> +  attrs = Fcons (Fcons (Qttname, build_string (procbuf)), attrs);
> 
> Is what you read from /proc/<pid>/ctty guaranteed to be pure-ASCII
> string?

Yes.  It's typically something like "/dev/pty0".

> P.S. Doesn't this warrant a NEWS entry?

Revised patch attached, with a NEWS entry.

Ken

[0001-Implement-system_process_attributes-on-Cygwin.patch (text/plain, attachment)]

Message #17 received at 55153 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Ken Brown <kbrown <at> cornell.edu>
Cc: 55153 <at> debbugs.gnu.org
Subject: Re: bug#55153: 29.0.50; Implement system_process_attributes on Cygwin
Date: Wed, 27 Apr 2022 20:12:27 +0300

> Date: Wed, 27 Apr 2022 12:45:45 -0400
> Cc: 55153 <at> debbugs.gnu.org
> From: Ken Brown <kbrown <at> cornell.edu>
> 
> > Is what you read from /proc/<pid>/ctty guaranteed to be pure-ASCII
> > string?
> 
> Yes.  It's typically something like "/dev/pty0".
> 
> > P.S. Doesn't this warrant a NEWS entry?
> 
> Revised patch attached, with a NEWS entry.

Thanks, LGTM.

Message #22 received at 55153-done <at> debbugs.gnu.org (full text, mbox):

From: Ken Brown <kbrown <at> cornell.edu>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: 55153-done <at> debbugs.gnu.org
Subject: Re: bug#55153: 29.0.50; Implement system_process_attributes on Cygwin
Date: Wed, 27 Apr 2022 13:25:38 -0400

On 4/27/2022 1:12 PM, Eli Zaretskii wrote:
> Thanks, LGTM.

Pushed to master.  Closing.

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