write to slots file as normal user?

[Drew Fustini]

This person noticed that Adafruit_BBIO doesn't work when not root:
https://forums.adafruit.com/viewtopic.php?f=49&t=105847#p606973

Issue seems to be:
open("/sys/devices/platform/bone_capemgr/slots", O_RDWR|O_LARGEFILE) = -1
EACCES (Permission denied)

Do we want to let normal users write to
/sys/devices/platform/bone_capemgr/slots ?

Thanks,
Drew

[Peter Lawler]

. chmod 664 /sys/devices/platform/bone_capemgr/slots

 

 
$groupadd --system slots
$usermod --append --groups slots debian
then
$chmod 664 /sys/devices/platform/bone_capemgr/slots
$chgrp slots /sys/devices/platform/bone_capemgr/slots
(though to be honest I have no idea if this would be permanent etc. and probably not, it would be 'nice')

[Robert Nelson]

we could just add a udev rule too. ;)

Regards,

--
Robert Nelson
https://rcn-ee.com/

[Peter Lawler]

You kids these days.... :-P

[Jason Kridner]

It would be a pretty big security hole, but we have plenty of those. It would at least take a targeted attack. I'm in favor. 

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[Drew Fustini]

Thanks, Peter. After running those commands, I was able to write to
slots file as user debian.

On Thu, Aug 31, 2017 at 6:56 AM, Peter Lawler <relwa...@gmail.com> wrote:
>
>

> --
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[tdlivings]

Did not work for me.

I attached the terminal dumps.

ssh into BBBW apply commands try python and sudo python failed both times is first file.

Power down reboot and try again is second file.

Tom

[Robert Nelson]

On Fri, Sep 1, 2017 at 1:18 PM, tdlivings <tdli...@gmail.com> wrote:
> Did not work for me.
>
> I attached the terminal dumps.
> ssh into BBBW apply commands try python and sudo python failed both times is
> first file.
> Power down reboot and try again is second file.

{RuntimeError: Unable to setup ADC system. Possible causes are:
- A cape with a conflicting pin mapping is loaded
- A device tree object is loaded that uses the same name for a
fragment: helper}

adc is already loaded..

This would show that:

sudo /opt/scripts/tools/version.sh

http://elinux.org/Beagleboard:BeagleBoneBlack_Debian#U-Boot_Disable_on-board_devices

see the adc disable..

[tdlivings]

Robert 

I do not know what you mean by adc is already loaded as it is part of a python module but let's just assume I am the unknowing one.

I ran your version.sh and here is the results

Last login: Fri Sep  1 18:02:47 2017 from 192.168.0.15

debian@beaglebone:~$ sudo /opt/scripts/tools/version.sh 

[sudo] password for debian: 

git:/opt/scripts/:[8e0b1e6f135ff3c30468f49a7a952c98be97219a]

eeprom:[A335BNLTBWA51646BBWG2052]

dogtag:[BeagleBoard.org Debian Image 2017-08-24]

bootloader:[microSD-(push-button)]:[/dev/mmcblk0]:[U-Boot 2017.09-rc2-00002-g84a7f2]

bootloader:[eMMC-(default)]:[/dev/mmcblk1]:[U-Boot 2017.03-rc1-00003-ga09f2d]

kernel:[4.4.83-ti-r119]

nodejs:[v6.11.2]

uboot_overlay_options:[enable_uboot_overlays=1]

uboot_overlay_options:[uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-4-TI-00A0.dtbo]

uboot_overlay_options:[enable_uboot_cape_universal=1]

pkg:[bb-cape-overlays]:[4.4.20170728.0-0rcnee1~stretch+20170728]

pkg:[bb-wl18xx-firmware]:[1.20170821-0rcnee1~stretch+20170821]

pkg:[firmware-ti-connectivity]:[20161130-3]

debian@beaglebone:~$ 

Tom

[Robert Nelson]

> bootloader:[microSD-(push-button)]:[/dev/mmcblk0]:[U-Boot
> 2017.09-rc2-00002-g84a7f2]
>
> bootloader:[eMMC-(default)]:[/dev/mmcblk1]:[U-Boot
> 2017.03-rc1-00003-ga09f2d]

So, your eMMC's bootloader is getting in the way, hence your not
booting what you expect:

so kill the MLO file via:

sudo dd if=/dev/zero of=/dev/mmcblk1 count=1 seek=1 bs=128k

and it'll default to the correct bootloader found on the microSD.

[tdlivings]

Robert

 Interesting as all I did was download the latest image you posted on Beagleboard.org and burn an sd card with it.

I expanded the file system and tried it out.

Seems to me if booting from an sd card the eMMC boot loader should neve be run.

I will give a try to killing the MLO file and I will see what image is actually in flash on this BBBW. 

Tom

[Robert Nelson]

On Fri, Sep 1, 2017 at 2:07 PM, tdlivings <tdli...@gmail.com> wrote:
> Robert
> Interesting as all I did was download the latest image you posted on
> Beagleboard.org and burn an sd card with it.
> I expanded the file system and tried it out.
> Seems to me if booting from an sd card the eMMC boot loader should neve be
> run.

The am335x's bootrom defaults to eMMC first...

> I will give a try to killing the MLO file and I will see what image is
> actually in flash on this BBBW.

[tdlivings]

Robert

OK deleted the file using your command and after a reboot it worked running python without sudo.

So whats in flash is upsetting the system, I will see what is in flash after dinner.

Last login: Fri Sep  1 19:16:09 2017 from 192.168.0.15

debian@beaglebone:~$ uname -a

Linux beaglebone 4.4.83-ti-r119 #1 SMP Thu Aug 17 06:39:24 UTC 2017 armv7l GNU/Linux

debian@beaglebone:~$ cat /etc/dogtag

BeagleBoard.org Debian Image 2017-08-24

debian@beaglebone:~$ python

Python 2.7.13 (default, Jan 19 2017, 14:48:08) 

[GCC 6.3.0 20170118] on linux2

Type "help", "copyright", "credits" or "license" for more information.

>>> import Adafruit_BBIO.ADC as ADC

>>> ADC.setup()

>>> ADC.readraw("AIN1")

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

AttributeError: 'module' object has no attribute 'readraw'

>>> ADC.read_raw("AIN1")

3648.0

>>> quit()

debian@beaglebone:~$ 

Tom

[tdlivings]

Robert

 Turns out what was in flash was dead, would not even boot.

I may have booted from flash on this board once when I first purchased the board last fall.

So I have no idea what happened to  flash or when.

So I downloaded the latest 08/31/2017 IOT image and converted it to a flasher image and

flashed the eMMC with it.

It flashed fine and booted, which said at least the eMMC was not defective

I took a look at what was there using a cloud9 terminal as I have not run connman yet

and tried python Adafruit_BBIO ADC and it worked.

I did not execute any of the commands to create a new group and change file permissions.

It just worked out of the box.

Did you make any changes to the 08/31 image from this discussion that would have fixed the issue?

Tomorrow I can try an sd card with a fresh image without the fixed discussed earlier today and see what

happens with flash having a good image. 

Here is what I did

debian@beaglebone:/var/lib/cloud9$ uname -a

Linux beaglebone 4.4.84-ti-r120 #1 SMP Sun Aug 27 03:11:07 UTC 2017 armv7l GNU/Linux

debian@beaglebone:/var/lib/cloud9$ cat /etc/dogtag

BeagleBoard.org Debian Image 2017-08-31

debian@beaglebone:/var/lib/cloud9$ df -h

Filesystem      Size  Used Avail Use% Mounted on

udev            217M     0  217M   0% /dev

tmpfs            49M  4.9M   44M  10% /run

/dev/mmcblk1p1  3.5G  1.6G  1.7G  48% /

tmpfs           244M     0  244M   0% /dev/shm

tmpfs           5.0M  4.0K  5.0M   1% /run/lock

tmpfs           244M     0  244M   0% /sys/fs/cgroup

debian@beaglebone:/var/lib/cloud9$ python

Python 2.7.13 (default, Jan 19 2017, 14:48:08)

[GCC 6.3.0 20170118] on linux2

Type "help", "copyright", "credits" or "license" for more information.

>>> import Adafruit_BBIO.ADC as ADC

>>> ADC.setup()

>>> ADC.read_raw("AIN0")

3950.0

>>> quit()

debian@beaglebone:/var/lib/cloud9$

Tom

[tdlivings]

Robert

Testing update

I made a clean 08-31-2917 sd card image and bootsd it to see if that

worked as well and it worked running python and the ADC test.

I did the test both in cloud9 and ssh into as debian user.

I made none of the fixes from this thread to the image just booted and

tried the ADC test

So 08-31-2017 image works in flash as stated in my previous post and 

from an sd card with a working 0831-2017 image in eMMC.

So I ask did you apply a fix to the 08-31-2017 image such as the udder rule

mentioned here.

Tom