Missing interfaces to sysfs

vtinelli · July 9, 2018, 3:56pm

Looking at interfaces definition and snapd code, there’s no interface for these sysfs interfaces:

axp20x sysfs interface: /sys/power/axp_pmu/ac/connected

Non-standard interface and requires a patch.

Thermal interface: /sys/class/thermal/thermal_zone0/temp

Standard interface.

It makes sense to request a new interface for thermal as it is standard, but not for the first one…

Do you have plans to allow this thru gadget as it is hardware related ?

kyleN · July 9, 2018, 4:03pm

Hi,

It turns out that hardware-observe provides read access to the thermal path needed:

github.com

snapcore/snapd/blob/master/interfaces/builtin/hardware_observe.go#L46


# used by lscpu and 'lspci -A intel-conf1/intel-conf2'
capability sys_rawio,
# see loaded kernel modules
@{PROC}/modules r,
# used by lspci
capability sys_admin,
/etc/modprobe.d/{,*} r,
/lib/modprobe.d/{,*} r,
# files in /sys pertaining to hardware (eg, 'lspci -A linux-sysfs')
/sys/{block,bus,class,devices,firmware}/{,**} r,
# files in /proc/bus/pci (eg, 'lspci -A linux-proc')
@{PROC}/bus/pci/{,**} r,
# DMI tables
/sys/firmware/dmi/tables/DMI r,
/sys/firmware/dmi/tables/smbios_entry_point r,

jdstrand · July 9, 2018, 4:35pm

Do you just need read-only access? /sys/power is standard, even if /sys/power/axp_pmu is not, so this could be something to consider adding to hardware-observe.

vtinelli · July 10, 2018, 8:54am

read-only access is fine for our use-case.

vtinelli · July 10, 2018, 8:54am

snap already has hardware-observe, probably got confused by failures related to other path.
Will check again and update the thread.

jdstrand · July 10, 2018, 8:36pm

Thanks, I’ll add this to the next batch of updates.

jdstrand · August 14, 2018, 1:21pm