lcd4linux-users

[lcd4linux] start/stop LCD4LINUX from webserver

[Piet v. d. B. <pi...@pi...>]

Hi all.

How can I start stop LCD4LINUX from a PHP script running
on an Apache webserver.
When i use exec() the command is refused because the user is
apache and lcd4linux only allows to run from root user.

Any one that can help ?

Piet

Re: [lcd4linux] start/stop LCD4LINUX from webserver

[Michael R. <re...@eu...>]

Hi Piet,

> How can I start stop LCD4LINUX from a PHP script running
> on an Apache webserver.
> When i use exec() the command is refused because the user is
> apache and lcd4linux only allows to run from root user.

No, that's not true. Basically LCD4Linux could run as any user. But
there's a security check, it refuses to work if the config file (usually
/etc/lcd4linux.conf) does not belong to the current user, and/or group
or others have access to it.

So if you want to run lcd4linux as 'apache', make shure that
/etc/lcd4linux.conf is owned by apache, too, and that it's permissions
are 0600. Depending on your display, the user apache must have access to
the LCD device, too.


HTH, Michael

-- 
Michael Reinelt <re...@eu...>
http://home.pages.at/reinelt
GPG-Key 0xDF13BA50
ICQ #288386781

Re: [lcd4linux] start/stop LCD4LINUX from webserver

[Piet v. d. B. <pi...@pi...>]

Hi Michael,

Thanks for your reply.
I use a lcd on a USB port with lcd2usb interface.
It works now.

regards Piet

On 19 Feb 2007 at 6:44, Michael Reinelt wrote:

> Hi Piet,
> 
> > How can I start stop LCD4LINUX from a PHP script running
> > on an Apache webserver.
> > When i use exec() the command is refused because the user is
> > apache and lcd4linux only allows to run from root user.
> 
> No, that's not true. Basically LCD4Linux could run as any user. But
> there's a security check, it refuses to work if the config file (usually
> /etc/lcd4linux.conf) does not belong to the current user, and/or group
> or others have access to it.
> 
> So if you want to run lcd4linux as 'apache', make shure that
> /etc/lcd4linux.conf is owned by apache, too, and that it's permissions
> are 0600. Depending on your display, the user apache must have access to
> the LCD device, too.
> 
> 
> HTH, Michael
> 
> -- 
> Michael Reinelt <re...@eu...>
> http://home.pages.at/reinelt
> GPG-Key 0xDF13BA50
> ICQ #288386781

Re: [lcd4linux] start/stop LCD4LINUX from webserver

[Johan S. <Joh...@xs...>]

Piet van den Bos wrote:
> Hi all.
> 
> How can I start stop LCD4LINUX from a PHP script running
> on an Apache webserver.
> When i use exec() the command is refused because the user is
> apache and lcd4linux only allows to run from root user.
> 
> Any one that can help ?

The insecure solution: make lcd4linux a set-uid-root program
(   chmod u+s `which lcd4linux`    should do the trick)

The secure solution: write a very small and obviously correct
program that starts and stops lcd4linux depending on the existance
of a file (or better input from a socket). Now let your PHP
script manipulate that file  (or output to the socket).


Regards, Johan

> 
> Piet
> 
>