The hardware-observe interface

degville · October 11, 2018, 12:14pm

The hardware-observe interface allows for getting hardware information from the system.

hardware-observe grants read-only access to many files and directories, primarily in /sys and /proc. Additionally, it provides access to many utility files and binaries such as lspci, lsusb, and hwinfo.

hardware-observe is a more general and broad interface. If more specific hardware access is required, such as for GPIO or I2C devices, See the gpio and i2c interfaces.

Interface documentation:

See Interface management and Supported interfaces for further details on how interfaces are used.

Developer details

Auto-connect: no

Path access

hardware-observe grants read access to the following paths:

For tools like hwinfo --short to get hardware information:
/proc/ioports
/proc/dma
/proc/tty/driver/{,*}
/proc/sys/dev/cdrom/info
For tools like lshw -quiet to get hardware information:
/proc/devices
/proc/ide/{,**}
/proc/scsi/{,**}
/proc/device-tree/{,**}
/sys/kernel/debug/usb/devices
/proc/sys/abi/{,*}
For tools like lspci -A linux-sysfs to get information on files in /sys:
/sys/{block,bus,class,devices,firmware}/{,**}
For tools like lspci -A linux-proc to get information on /proc:
/bus/pci/{,**} /{,usr/}lib/modprobe.d/{,*}
For tools like lspci -k to get information on loaded modules:
Examples: /etc/modprobe.d/{,*},
For tools like lsusb to get USB information:
/var/lib/usbutils/usb.ids
/dev/
/dev/bus/usb/{,**/}
/etc/udev/udev.conf
Note: lsusb and its database have to be shipped in the snap if not on classic
For tools like sensors to get sensor information:
/etc/sensors3.conf
/etc/sensors.d/{,*}
For tools like udevadm to get device information:
/run/udev/data/**
For hugepage and transparent_hugepage statuses (but not the pages themselves):
/sys/kernel/mm/{hugepages,transparent_hugepage}/{,**}
For information on available input devices:
/proc/bus/input/devices
For power information:
/sys/power/{,**}
/run/udev/data/+power_supply:*
For interrupts:
/proc/interrupts
For loaded kernel module information:
/proc/modules
For VM information:
/proc/cpuinfo
/proc/sysinfo
/proc/xen/capabilities
/proc/1/sched
/sys/hypervisor/properties/features
/sys/hypervisor/type
For container information:
/run/systemd/container

Binary access

hardware-observe grants executable access to the following binaries:

For tools provided by util-linux:
/{,usr/}bin/lsblk
/{,usr/}bin/lscpu
/{,usr/}bin/lsmem
For tools like lsusb:
/{,usr/}bin/lsusb
For tools like systemd-detect-virt:
/{,usr/}bin/systemd-detect-virt

Capability access

hardware-observe grants the following capabilities:

For tools like lscpu and lspci -A to inspect specific PCI access methods:
capability sys_rawio
capability sys_admin

Socket access

hardware-observe grants the following socket access:

For udevadm to read netlink:
network netlink raw

The test code for the interface is in the snapd repository: https://github.com/canonical/snapd/blob/master/interfaces/builtin/hardware_observe_test.go

The source code for the interface is in the snapd repository: https://github.com/canonical/snapd/blob/master/interfaces/builtin/hardware_observe.go

snowsky · February 24, 2021, 3:30pm

Hey there,

It would be more helpful to copy the folders and files from the codes, https://github.com/snapcore/snapd/blob/master/interfaces/builtin/hardware_observe.go.

Thanks, Hao

dilyn · August 13, 2024, 10:23pm

What a great idea!

@degville a potential rewrite.

My one concern is maintainability, although hardware_observe.go sees very limited action.

Hidden rewrite to save vertical space