I've been learning to use udev and noticed that when I run udevadm test --action="add" /sys/block/sdc
I see the following:
GROUP 6 /usr/lib/udev/rules.d/50-udev-default.rules:59
IMPORT 'scsi_id --export --whitelisted -d /dev/sdc' /usr/lib/udev/rules.d/60-persistent-storage.rules:50
starting 'scsi_id --export --whitelisted -d /dev/sdc'
'scsi_id --export --whitelisted -d /dev/sdc'(out) 'ID_SCSI=1'
'scsi_id --export --whitelisted -d /dev/sdc'(out) 'ID_VENDOR=NVMe'
'scsi_id --export --whitelisted -d /dev/sdc'(out) 'ID_VENDOR_ENC=NVMe\x20\x20\x20\x20'
'scsi_id --export --whitelisted -d /dev/sdc'(out) 'ID_MODEL=Dell_Ent_NVMe_v2'
'scsi_id --export --whitelisted -d /dev/sdc'(out) 'ID_MODEL_ENC=Dell\x20Ent\x20NVMe\x20v2'
'scsi_id --export --whitelisted -d /dev/sdc'(out) 'ID_REVISION=.2.0'
'scsi_id --export --whitelisted -d /dev/sdc'(out) 'ID_TYPE=disk'
'scsi_id --export --whitelisted -d /dev/sdc'(out) 'ID_SERIAL=236435330529024120025384100000002'
'scsi_id --export --whitelisted -d /dev/sdc'(out) 'ID_SERIAL_SHORT=36435330529024120025384100000002'
'scsi_id --export --whitelisted -d /dev/sdc'(out) 'ID_SCSI_SERIAL=S6CSNA0R902412 '
Process 'scsi_id --export --whitelisted -d /dev/sdc' succeeded.
sdc in this case is a virtual disk sitting on a PERC H755. I have not yet changed anything in udev.
The above is what you see when using a RAID0 (passthrough/JBOD mode). If you create a RAID 5 you see
probe /dev/sda raid offset=0
LINK 'disk/by-id/wwn-0x6f4ee080160bd5002ab7652100a1691a' /usr/lib/udev/rules.d/60-persistent-storage.rules:97
IMPORT '/usr/bin/sg_inq --export --inhex=/sys/block/sda/device/inquiry --raw' /usr/lib/udev/rules.d/61-scsi-sg3_id.rules:17
starting '/usr/bin/sg_inq --export --inhex=/sys/block/sda/device/inquiry --raw'
'/usr/bin/sg_inq --export --inhex=/sys/block/sda/device/inquiry --raw'(out) 'SCSI_TPGS=0'
'/usr/bin/sg_inq --export --inhex=/sys/block/sda/device/inquiry --raw'(out) 'SCSI_TYPE=disk'
'/usr/bin/sg_inq --export --inhex=/sys/block/sda/device/inquiry --raw'(out) 'SCSI_VENDOR=DELL'
'/usr/bin/sg_inq --export --inhex=/sys/block/sda/device/inquiry --raw'(out) 'SCSI_VENDOR_ENC=DELL\x20\x20\x20\x20'
'/usr/bin/sg_inq --export --inhex=/sys/block/sda/device/inquiry --raw'(out) 'SCSI_MODEL=PERC_H755N_Front'
'/usr/bin/sg_inq --export --inhex=/sys/block/sda/device/inquiry --raw'(out) 'SCSI_MODEL_ENC=PERC\x20H755N\x20Front'
'/usr/bin/sg_inq --export --inhex=/sys/block/sda/device/inquiry --raw'(out) 'SCSI_REVISION=5.16'
My question is how is udev "deciding" to whitelist the PERC and what is the function of whitelisting?
Research Done
- Read through this post on whitelisting for USB drives but this seems to be used when someone makes the decision to manually disallow all USB devices except certain targets which isn't applicable here.
- This tutorial on writing udev scripts but it didn't answer any of my questions about whitelisting.
- The udev Wikipedia but while that gave me a better architectural understanding it didn't help me with whitelisting
- The man page for udev - helpful but no mention of whitelisting.
In general I tried Googling for results related to udev whitelisting but the only results I could find were all about whitelisting USB devices rather than how whitelisting generally functions.