Re: have emacs use SIGTERM to end a process instead of SIGHUP

Re: have emacs use SIGTERM to end a process instead of SIGHUP

[Barry Margolin]

In article <mailman.586.1373322303.12400.help-gnu-emacs@gnu.org>,
 John Leach <john@johnleach.co.uk> wrote:

> Hi,
> 
> I'm starting a process using start-process-shell-command, but the
> command I'm running doesn't exit when it receives a SIGHUP (it reloads
> it's configs or something) so I end up with orphaned processes hanging
> around when I close the buffer or exit emacs.

That's really strange behavior for a non-daemon process. Wouldn't it 
have the same problem if you ran it from a normal terminal and 
disconnected?

SIGHUP is the expected signal when a process's terminal goes away.

-- 
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***

Re: have emacs use SIGTERM to end a process instead of SIGHUP

[John Leach]

On 09/07/13 16:19, Barry Margolin wrote:
> In article <mailman.586.1373322303.12400.help-gnu-emacs@gnu.org>,
>  John Leach <john@johnleach.co.uk> wrote:
> 
>> Hi,
>>
>> I'm starting a process using start-process-shell-command, but the
>> command I'm running doesn't exit when it receives a SIGHUP (it reloads
>> it's configs or something) so I end up with orphaned processes hanging
>> around when I close the buffer or exit emacs.
> 
> That's really strange behavior for a non-daemon process. Wouldn't it 
> have the same problem if you ran it from a normal terminal and 
> disconnected?
> 
> SIGHUP is the expected signal when a process's terminal goes away.
> 

true - it's probably a good idea for me to submit a patch to this
program to have it behave properly.

John.

have emacs use SIGTERM to end a process instead of SIGHUP

[John Leach]

Hi,

I'm starting a process using start-process-shell-command, but the
command I'm running doesn't exit when it receives a SIGHUP (it reloads
it's configs or something) so I end up with orphaned processes hanging
around when I close the buffer or exit emacs.

How can I have emacs send a SIGTERM instead of a SIGHUP to the processes
it manages?

fyi, I define a function to start the process like this:

> (defun nanoc-server ()
> 	"Runs a nanoc web server"
> 	(interactive)
> 	(let ((default-directory (repository-root)))
> 		(let ((process-connection-type t))
> 			(start-process-shell-command "nanoc-server" "nanoc-server" "bundle exec nanoc view -p 3005 -C")
> 			)))

Thanks in advance for any help,

John.
--
http://johnleach.co.uk

Re: have emacs use SIGTERM to end a process instead of SIGHUP

[Tassilo Horn]

John Leach <john@johnleach.co.uk> writes:

Hi John,

> I'm starting a process using start-process-shell-command, but the
> command I'm running doesn't exit when it receives a SIGHUP (it reloads
> it's configs or something) so I end up with orphaned processes hanging
> around when I close the buffer or exit emacs.

I guess you could add a function to `kill-buffer-hook' that calls
`delete-process' on the process.

Bye,
Tassilo

Re: have emacs use SIGTERM to end a process instead of SIGHUP

[John Leach]

On 09/07/13 13:02, Tassilo Horn wrote:
> John Leach <john@johnleach.co.uk> writes:
> 
> Hi John,
> 
>> I'm starting a process using start-process-shell-command, but the
>> command I'm running doesn't exit when it receives a SIGHUP (it reloads
>> it's configs or something) so I end up with orphaned processes hanging
>> around when I close the buffer or exit emacs.
> 
> I guess you could add a function to `kill-buffer-hook' that calls
> `delete-process' on the process.

thanks Tassilo. I'm trying to do this but failing.

So I think I need a kill-buffer-hook that can get the process of the
current buffer, check if it looks like the process I know needs a
SIGTERM, and then send it one.

I'm wondering if I can set some kind of attribute on the buffer when I
create the process, so I can easily recognise it at kill time? Rather
than looking at the command line or something.

I'm lost with even the basic syntax to do any of this though. Could you
help?

Thanks,

John.

Re: have emacs use SIGTERM to end a process instead of SIGHUP

[Tassilo Horn]

John Leach <john@johnleach.co.uk> writes:

>>> I'm starting a process using start-process-shell-command, but the
>>> command I'm running doesn't exit when it receives a SIGHUP (it
>>> reloads it's configs or something) so I end up with orphaned
>>> processes hanging around when I close the buffer or exit emacs.
>> 
>> I guess you could add a function to `kill-buffer-hook' that calls
>> `delete-process' on the process.
>
> thanks Tassilo. I'm trying to do this but failing.
>
> So I think I need a kill-buffer-hook that can get the process of the
> current buffer, check if it looks like the process I know needs a
> SIGTERM, and then send it one.
>
> I'm wondering if I can set some kind of attribute on the buffer when I
> create the process, so I can easily recognise it at kill time?

You could use a buffer-local variable.  E.g.

--8<---------------cut here---------------start------------->8---
(defvar nanoc-process nil)
(make-variable-buffer-local 'nanoc-process)

(defun nanoc-kill-process ()
  (when nanoc-process
    (delete-process nanoc-process)))

(defun nanoc-server ()
  "Runs a nanoc web server"
  (interactive)
  (let ((default-directory (repository-root))
        (process-connection-type t))
    (setq nanoc-process
          (start-process-shell-command
           "nanoc-server" "nanoc-server"
           "bundle exec nanoc view -p 3005 -C"))
    (add-hook 'kill-buffer-hook #'nanoc-kill-process nil t)))
--8<---------------cut here---------------end--------------->8---

Then every buffer may have its own nanoc-server process, and when
killing the buffer only that buffer's process is deleted.

Bye,
Tassilo