Bug 244867

Summary:

Provide sysctl kern.boot_id

Product:

Base System

Reporter:

Ricardo Fraile <r>

Component:

kern

Assignee:

Conrad Meyer <cem>

Status:

Closed FIXED

Severity:

Affects Some People

CC:

emaste, r

Priority:

---

Keywords:

feature

Version:

Unspecified

Flags:

cem: mfc-stable12-
cem: mfc-stable11-

Hardware:

Any

OS:

Any

Attachments:

Description	Flags
Fix output for sysctl kern.boot_id	none
Update man 3 syctl with kern_boot_id	none
Update man 8 syctl with kern_boot_id and order list	none

Description Ricardo Fraile 2020-03-17 19:08:20 UTC

Hello,


Tracking a new startup of the system usually fall into looking kern.boottime. But it isn't constant, sometimes drifts over time, so it isn't a 100% reliable source.

On Linux implemented /proc/sys/kernel/random/boot_id [1] with a random value generated early at boot, unique for every running kernel instance.

It would be nice to have it on FreeBSD too.



Thanks,



[1] - http://man7.org/linux/man-pages/man3/sd_id128_get_machine.3.html

Comment 1 Conrad Meyer freebsd_committer

2020-03-17 20:55:29 UTC

I agree that this would be useful to provide, and seems straightforward enough.

Comment 2 Kubilay Kocak freebsd_committer

2020-03-17 21:13:34 UTC

To clarify, this is different from kern.hostuuid (and kern.hostid an alias, set via /etc/rc.d/hostid) in that each *boot* gets a new id, rather than a once per install, which is constant/immutable/read-only until the next boot? 

I also note that for kern.hostuuid, there's an associated security.jail.param.host.hostuuid sysctl.

Presumably this feature request should also apply to jails too?

Comment 3 commit-hook freebsd_committer

2020-03-17 22:28:01 UTC

A commit references this bug:

Author: cem
Date: Tue Mar 17 22:27:17 UTC 2020
New revision: 359053
URL: https://svnweb.freebsd.org/changeset/base/359053

Log:
  Implement sysctl kern.boot_id

  Boot IDs are random, opaque 128-bit identifiers that distinguish distinct
  system boots.  A new ID is generated each time the system boots.  Unlike
  kern.boottime, the value is not modified by NTP adjustments.  It remains fixed
  until the machine is restarted.

  PR:		244867
  Reported by:	Ricardo Fraile <rfraile AT rfraile.eu>
  MFC after:	I do not intend to, but feel free

Changes:
  head/sys/kern/kern_mib.c

Comment 4 Conrad Meyer freebsd_committer

2020-03-17 22:28:10 UTC

Dropping if someone wants to MFC or further enhance re jails.

Comment 5 Ricardo Fraile 2020-03-19 19:48:01 UTC

Thanks for the quick response. 

I just tried the last snapshop of 13.0-CURRENT x86 build today and the option doesn't fail but it doesn't report anything.


root@:~ # sysctl kern.boot_id
root@:~ # echo $?
0
root@:~ #

Comment 6 Ricardo Fraile 2020-03-29 15:52:02 UTC

Created attachment 212834 [details]
Fix output for sysctl kern.boot_id

Comment 7 Ricardo Fraile 2020-03-29 15:53:17 UTC

Created attachment 212836 [details]
Update man 3 syctl with kern_boot_id

Comment 8 Ricardo Fraile 2020-03-29 15:54:02 UTC

Created attachment 212837 [details]
Update man 8 syctl with kern_boot_id and order list

Comment 9 Ricardo Fraile 2020-03-29 15:54:49 UTC

I fix it with this code change, please see the patch uploaded. Also, there are two other patches to update man pages.

root@:~ # sysctl kern.boot_id
kern.boot_id: 16254718031988427779

Comment 10 Ricardo Fraile 2020-04-23 06:23:51 UTC

@cem did you see the last patches? is needed something more?

Having the functionality working on -current can allow to test it right, it would be helpful.

Thanks,

Comment 11 Ricardo Fraile 2020-06-21 11:25:45 UTC

Hello,

On FreeBSD-13.0-CURRENT-i386-20200611-r362037 I still have an empty output.

root@:~ # sysctl kern.boot_id


Thanks,

Comment 12 Mark Linimon freebsd_committer

2020-07-30 23:19:29 UTC

^Triage: assign to committer.

Comment 13 Conrad Meyer freebsd_committer

2020-07-30 23:36:02 UTC

To print this value, one option is to use sysctl -x:

$ sysctl -x kern.boot_id
kern.boot_id: Format: Length:16 Dump:0x75ca41033699ae64afe63a45a6b5d258

The patch in comment #6 does not seem necessary or correct.

The patch in comment #7 documents a non-existent KERN_BOOT_ID identifier.

The patch in comment #8 combines an add and sort; those should be independent so it is clear what is being changed.

Cleared 'patch' tag.

Comment 14 Conrad Meyer freebsd_committer

2020-07-30 23:38:19 UTC

(In reply to Ricardo Fraile from comment #8)
Hm, and sysctl.8 is not an exhaustive list of all sysctls.  Mostly the tree is self-documenting or documented elsewhere.  I'm not sure adding this to that page is justified.