--- In "naturalwatt" <> wrote:
>
>
> I don't think anyone EXCEPT root is allowed to open /dev/mem.
>
> --- In "n4rve" <wordy@> wrote:
> >
> > Hi...
> >
> > I'm just beginning to get my feet wet (OK, barely moist) with this board,
> > so please forgive me if this is a PEBCAK (Problem Exists Between Chair And
> > Keyboard).
> >
> > When my 7800 first came up, I was able to use ts7800ctl -n and -F to turn
> > the LED on and off. This was fairly exciting, and worked both in root and
> > my user account.
> >
> > However, the next time I tried ts7800ctl in the user account (and every
> > time since) I receive this error message on any option:
> >
> > ts7800ctl: ts7800ctl.c:175: main: Assertion `devmem != -1' failed.
> > Aborted
> >
> > This kind of error is associated with failing to close /dev/mem in a
> > program after opening it, and sure enough, when I look at the source:
> >
> > ftp://ftp.embeddedarm.com/tmp/7800_adc_update/ts7800ctl.c
> >
> > I see
> >
> > devmem = open("/dev/mem", O_RDWR|O_SYNC);
> >
> > just before all the case statements. There is no close. Clearly, however,
> > this must be working for other people as it is often cited... so I can't
> > imagine that's really the problem.
> >
> > The puzzle, perhaps negating the question above, is why am I getting the
> > abort message on every attempt to use it in user space, even though it
> > still works fine in root (assuming I use the explicit path of
> > /usr/local/bin/)?
'User space' refers to anything other than 'kernel space' (kernel itself,
device drivers, etc). So running ts7800ctl is user space, whether run by root
or a user.
Check to see if the suid bit has been turned off on the executable file.
regards, .......... Charlie
> >
> > Cheers,
> > Steve
> > (who is still puzzled about the lack of sudo)
> >
>
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