On Thu, 13 Jan 2011, frankvd99 wrote:
> Hi Jonatan, Jim,
> Thanks for your feedback.
>
> I've tried to do a chmod 666 on /dev/mem but that still does not solve
> the problem. Also when I reboot the system the properties are set back to
> 600
... I'm not surprised.
> I find conflicting information when I google around on this topic. Some
> are saying /dev/mem will give access to the memory from the user space.
> Others are saying you need to create a driver to get access to it.
>
> To me it is strange that there are several examples from Technologic
> Systems available but there is never a notice that you should run it as
> root. ftp://ftp.embeddedarm.com/ts-arm-sbc/ts-7500-linux/samples/dio.c
Probably they assume there users have sufficient Linux knowledge
> Are there other users of the TS7500 board who have different properties
> for /dev/mem? I've downloaded and installed debian linux from the
> Technologic FTP site a few weeks ago. Apart from some network settings I
> did not change a lot yet.
You seem to have completely ignored my advice about using a setuid wrapper
program. Seems you can't help some people <shrug>.
>
> --- In Jim Jackson <> wrote:
> >
> >
> >
> >
> > On Thu, 13 Jan 2011, frankvd99 wrote:
> >
> > > I have a TS7500 board and trying to control the digital IO lines from
> > > Debian-linux on the sd-card.
> > >
> > > When running the script below as user "root" it works fine. When doing
> > > the same thing as user eclipse (or any other user) I get below message.
> > >
> > >
> > > #!/bin/sh
> > > . /initrd/ts7500.subr
> > > #
> > > echo "IO value of pin 5:"
> > > getdiopin 5
> > > #
> > >
> > > Response when user root:
> > > IO value of pin 5:
> > > 1
> > >
> > > Response when user eclipse:
> > > ts7500ctl: ts7500ctl.c: 771 main: Assertion 'dev/mem !=-1' failed
> > >
> > > I've traced this back to the ts7500ctl.c file which is trying to open
> > > /dev/mem, which is not allowed.
> > >
> > > Is there another way how I can get this done. My goal is to run TS7500
> > > digital IO control from a CGI script in the Apache webserver. Apache does
> > > not allow you to run it as root, so that is not a workaround.
> >
> > You need a setuid program - see [1] for an overview of permissions. I
> > believe you are not supposed to make scripts setuid, because of a possible
> > security hole, so you probably need a program "wrapper" for your script[2].
> >
> > Jim
> >
> > [1] http://www.zzee.com/solutions/linux-permissions.shtml
> > [2] http://www.tuxation.com/setuid-on-shell-scripts.html
> >
>
>
>
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