Problems starting emacs with correct environmental settings

Problems starting emacs with correct environmental settings

[Alain Muls]

Hi emacs users,

On my ubuntu system I have in the top bar the icon (dragged from the 
menu entry in Accessories) to launch emacs. By doing so, I have no 
access to my PATH variable, eg. a compile (make -k) won't run.

When I launch emacs from a shell, than there is no problem and make or 
other scripts are available. What should I do to have the icon launch 
emacs with my PATH set.

Tx/Alain


---------------------------------------------------------------------
Alain Muls                                  alain.muls@septentrio.com
                                                        +32.477.675091

Re: Problems starting emacs with correct environmental settings

[Pascal J. Bourguignon]

Alain Muls <alain.muls@telenet.be> writes:

> Hi emacs users,
>
> On my ubuntu system I have in the top bar the icon (dragged from the
> menu entry in Accessories) to launch emacs. By doing so, I have no
> access to my PATH variable, eg. a compile (make -k) won't run.
>
> When I launch emacs from a shell, than there is no problem and make or
> other scripts are available. What should I do to have the icon launch
> emacs with my PATH set.

You could launch a script instead of emacs.

But you may also set the environment variables from emacs:

(require 'cl)

(defun join (los sep)
  (with-output-to-string
     (princ (first los))
     (dolist (s (rest los))
        (princ sep) (princ s))))

(setf (getenv "PATH") (join (list* "/your/path" "/and/some/more" (getenv "PATH")) ":"))

-- 
__Pascal Bourguignon__

Re: Problems starting emacs with correct environmental settings

[Peter Dyballa]

Am 02.07.2009 um 21:22 schrieb Alain Muls:

> On my ubuntu system I have in the top bar the icon (dragged from  
> the menu entry in Accessories) to launch emacs. By doing so, I have  
> no access to my PATH variable, eg. a compile (make -k) won't run.


What is the mechanism behind it?
What is the behaviour when you launch GNU Emacs with '-u <your login  
name>'?
What is the behaviour when you launch GNU Emacs with '-l <some rather  
empty Emacs Lisp file, for example a message>'?
Is it possible to use a shell script as GNU Emacs entry which  
launches GNU Emacs?

--
Greetings

   Pete

The human animal differs from the lesser primates in his passion for  
lists of "Ten Best."
				– H. Allen Smith

Re: Problems starting emacs with correct environmental settings

[Jeff Clough]

Alain Muls wrote:
> Hi emacs users,
>
> On my ubuntu system I have in the top bar the icon (dragged from the 
> menu entry in Accessories) to launch emacs. By doing so, I have no 
> access to my PATH variable, eg. a compile (make -k) won't run.
>
> When I launch emacs from a shell, than there is no problem and make or 
> other scripts are available. What should I do to have the icon launch 
> emacs with my PATH set.
>

Running ubuntu 8.04 I have the following as my launcher in the same 
place it seems you do:

/usr/bin/emacs2-x

M-x compile brings up make -k and it works just fine.  No problems at 
all.  Anything I feed to this command as a "compiler" (cp, etc.) that's 
in my path resolves.

If your launcher is set up the same way, it smells like something more 
fundamental is broken. :(

Jeff

-- 

Author of the Genesys System
A "free" universal role-playing game.
http://www.chaosphere.com/genesys/

Re: Problems starting emacs with correct environmental settings

[Jeff Clough]

Jeff Clough wrote:
> Alain Muls wrote:
>> Hi emacs users,
>>
>> On my ubuntu system I have in the top bar the icon (dragged from the 
>> menu entry in Accessories) to launch emacs. By doing so, I have no 
>> access to my PATH variable, eg. a compile (make -k) won't run.
>>
>> When I launch emacs from a shell, than there is no problem and make 
>> or other scripts are available. What should I do to have the icon 
>> launch emacs with my PATH set.
>>
>
> Running ubuntu 8.04 I have the following as my launcher in the same 
> place it seems you do:
>
> /usr/bin/emacs2-x
>
Err... that's /usr/bin/emacs22-x

Dang '2' key sticks. :)

Jeff

-- 

Author of the Genesys System
A "free" universal role-playing game.
http://www.chaosphere.com/genesys/

Re: Problems starting emacs with correct environmental settings

[Pascal J. Bourguignon]

Alain Muls <alain.muls@telenet.be> writes:

> Hi emacs users,
>
> On my ubuntu system I have in the top bar the icon (dragged from the
> menu entry in Accessories) to launch emacs. By doing so, I have no
> access to my PATH variable, eg. a compile (make -k) won't run.
>
> When I launch emacs from a shell, than there is no problem and make or
> other scripts are available. What should I do to have the icon launch
> emacs with my PATH set.

If you answer Peter's questions, you will learn that environment
variables are inherited from parent process to child process, (some
programs do clean up environment variables before forking a child, but
normal programs leave them pass from parent to grand-child).

So ultimately, it depend on the process that forks emacs.  This is the
"desktop manager" (does something like KDE, Gnome, GNUstep Workspace
Manager, etc, ring a bell?).  Some of these desktop managers may
provide a preference panel to set the environment variables for the
child processes.  Or they may load them from a special file or store.
So if you identify your desktop manager, you may try to find this file
or this preference and set it.

Otherwise, you could set the environment in the process that launches
the desktop manager.

When you log in with X, the login window manager restarts the X server
which will execute some script to fork your window manager, desktop
manager, etc. Various user scripts may be used, like ~/.xsession or
~/.xinitrc, depending on the login window manager you use or how you
start X.  In the absence of user scripts, default scripts in
/etc/X11/* are used.

Depending on the shell used by these scripts, you may edit one of the
file used by these shell to set the environment. Eg. in case of bash,
you could set your environment in ~/.bash_env or ~/.bash_login or
~/.bashrc ; for other Bourne shells, ~/.profile or ~/.login could be
used.  In the last resort, you can directly edit the X startup scrip
that is used in your configuration.



You may follow the login process by starting from /etc/inittab, and
following the track of the programs/processes.

-- 
__Pascal Bourguignon__

Re: Problems starting emacs with correct environmental settings

[Peter Dyballa]

Am 03.07.2009 um 12:08 schrieb Pascal J. Bourguignon:

> Depending on the shell used by these scripts, you may edit one of the
> file used by these shell to set the environment. Eg. in case of bash,
> you could set your environment in ~/.bash_env or ~/.bash_login or
> ~/.bashrc ; for other Bourne shells, ~/.profile or ~/.login could be
> used.  In the last resort, you can directly edit the X startup scrip
> that is used in your configuration.


Alain send me some answers privately. To me it seems that processes  
created from the menu icons inherit only a small environment, could  
be that of a privileged process. It obviously has some basic  
components in PATH, but not Alain's private parts. And GNU Emacs  
actually is opened via emacsclient, from a shell script, which is  
passed to the launcher as " ~/..." and "~/" does not get expanded to  
something like "/home/<user>/..."

With pstree, observing such a launched process, one might find some  
basic clues. By using a shell script that creates a login shell to  
launch emacsclient from inside it a few problems could be cured…

--
Greetings

   Pete

It's not the valleys in life I dread so much as the dips.
				– Garfield

Re: Problems starting emacs with correct environmental settings

[Tim X]

Peter Dyballa <Peter_Dyballa@Web.DE> writes:

> Am 03.07.2009 um 12:08 schrieb Pascal J. Bourguignon:
>
>> Depending on the shell used by these scripts, you may edit one of the
>> file used by these shell to set the environment. Eg. in case of bash,
>> you could set your environment in ~/.bash_env or ~/.bash_login or
>> ~/.bashrc ; for other Bourne shells, ~/.profile or ~/.login could be
>> used.  In the last resort, you can directly edit the X startup scrip
>> that is used in your configuration.
>
>
> Alain send me some answers privately. To me it seems that processes created
> from the menu icons inherit only a small environment, could  be that of a
> privileged process. It obviously has some basic  components in PATH, but
> not Alain's private parts. And GNU Emacs  actually is opened via
> emacsclient, from a shell script, which is  passed to the launcher as "
> ~/..." and "~/" does not get expanded to  something like "/home/<user>/..."
>
> With pstree, observing such a launched process, one might find some basic
> clues. By using a shell script that creates a login shell to  launch
> emacsclient from inside it a few problems could be cured…
>
> --
> Greetings
>

Note that I'm speaking about accessing X from gdm/xdm/etc rather than
starting it with something like startx.

On modern Linux boxes, the scripts that start X do so in a non-login
shell. This means files like .bash_profile are not sourced. The X
session is normally run as the last stage in the startup process - often
the last line is something like

exec <window manager> 

which makes the current running process your X window manager
process. When you kill that process, you are logged out. 

The limitation of this approach is that your X window manager process
does not have all the environment settings that you would normally see
in a standard login shell. When the window manager forks another process
to launch something like emacs, it passes on its environment variables,
but as its not a login shell and .bash_profile has not been sourced, the
envrionment is somewhat limited. 

There are  a number of solutions you can use.

1. In the case of GDM, edit /etc/gdm/Xsession and make it either run as
a login shell or have it source your .bash_profile etc. 

2. Write a shell wrapper script which sources your environment scripts
and use it to launch programs from menus/icons etc. 

3. Start an xterm witht he -ls switches so that it starts as a login
shell and execute the programs from there. 

4. You can set some environment settings in the /etc/environment file,
but note that all processes source this file, including processes that
are not started by a specific user.

I use to change the first line of the Xsession script so that it runs as
a login shell and then I have all my environment settings. However, I
stopped doing that because everytime GDM was updated, I'd lose my
changes if the update included a new Xsession script. 

Now, I place settings that are common to all users/processes in
/etc/environment and I have a basic 'launcher' script that sources my
.bash_profile before starting a program like emacs. I use this script in
place of the standard things for opening an xterm or starting emacs. 

HTH

Tim

-- 
tcross (at) rapttech dot com dot au

Re: Problems starting emacs with correct environmental settings

[Johan Bockgård]

pjb@informatimago.com (Pascal J. Bourguignon) writes:

> (defun join (los sep)
>   (with-output-to-string
>      (princ (first los))
>      (dolist (s (rest los))
>         (princ sep) (princ s))))

  (mapconcat 'identity los sep)

Re: Problems starting emacs with correct environmental settings

[Pascal J. Bourguignon]

bojohan+news@dd.chalmers.se (Johan Bockgård) writes:

> pjb@informatimago.com (Pascal J. Bourguignon) writes:
>
>> (defun join (los sep)
>>   (with-output-to-string
>>      (princ (first los))
>>      (dolist (s (rest los))
>>         (princ sep) (princ s))))
>
>   (mapconcat 'identity los sep)

Great! Thank you.

-- 
__Pascal Bourguignon__