resolved dhclient-enter-hook complains about an empty file

[Craig Francis]

[impact]

When starting/using `dhclient`, it will often return an error such as:

    cmp: EOF on /tmp/tmp.yCyV6zBzhB which is empty

[test case]

run dhclient for the first time (for the current boot) on a bionic/focal system, or remove the file(s) in /run/systemd/resolved.conf.d/ starting with 'isc-dhcp-*', and then run dhclient.

[regression potential]

any regression would likely cause the DNS configuration that dhclient gets to not be properly reported to systemd-resolved, resulting in problematic/broken systemd DNS resolution.

[scope]

this is needed in b/f

this hook was removed from systemd starting in g, and the hook was not yet added in x, so this change is needed only in b and f.

[original description]

When starting/using `dhclient`, it will often return an error such as:

    cmp: EOF on /tmp/tmp.yCyV6zBzhB which is empty

This is due to the use of `cmp` in "/etc/dhcp/dhclient-enter-hooks.d/resolved"

Because the $oldstate file can be empty, or different, it should use `cmp --quiet`

This happens when "/run/systemd/resolved.conf.d/isc-dhcp-v*-$interface.conf" files do not exist, or when the content changes.

This is very loosely related to https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1805183

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Chris Halse Rogers (raof)]

Hello Craig, or anyone else affected,

Accepted systemd into focal-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/systemd/245.4-4ubuntu3.4 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-focal to verification-done-focal. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-focal. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

[Chris Halse Rogers (raof)]

Hello Craig, or anyone else affected,

Accepted systemd into bionic-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/systemd/237-3ubuntu10.44 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-bionic to verification-done-bionic. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-bionic. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

[Ubuntu SRU Bot (ubuntu-sru-bot)]

All autopkgtests for the newly accepted systemd (245.4-4ubuntu3.4) for focal have finished running.
The following regressions have been reported in tests triggered by the package:

linux-hwe-5.8/5.8.0-37.42~20.04.1 (arm64)
netplan.io/0.100-0ubuntu4~20.04.3 (amd64)
apt/2.0.2ubuntu0.2 (armhf)
munin/2.0.56-1ubuntu1 (ppc64el)
gvfs/1.44.1-1ubuntu1 (amd64, arm64)
prometheus-alertmanager/0.15.3+ds-3ubuntu1 (armhf)
lxc/1:4.0.2-0ubuntu1 (amd64)
indicator-session/17.3.20+19.10.20190921-0ubuntu1 (ppc64el)
pyudev/0.21.0-3ubuntu1 (s390x)

Please visit the excuses page listed below and investigate the failures, proceeding afterwards as per the StableReleaseUpdates policy regarding autopkgtest regressions [1].

https://people.canonical.com/~ubuntu-archive/proposed-migration/focal/update_excuses.html#systemd

[1] https://wiki.ubuntu.com/StableReleaseUpdates#Autopkgtest_Regressions

Thank you!

[Ubuntu SRU Bot (ubuntu-sru-bot)]

All autopkgtests for the newly accepted systemd (237-3ubuntu10.44) for bionic have finished running.
The following regressions have been reported in tests triggered by the package:

linux-azure-4.15/4.15.0-1104.116 (amd64)
munin/2.0.37-1ubuntu0.1 (arm64)
gvfs/1.36.1-0ubuntu1.3.3 (amd64)
libvirt/4.0.0-1ubuntu8.17 (i386)
apt/1.6.12ubuntu0.2 (armhf)
netplan.io/0.99-0ubuntu3~18.04.3 (amd64)
linux-hwe-5.0/5.0.0-63.69 (armhf)
openssh/1:7.6p1-4ubuntu0.3 (armhf, s390x, ppc64el, arm64, i386, amd64)
corosync/2.4.3-0ubuntu1.1 (armhf)
nut/2.7.4-5.1ubuntu2 (i386)

Please visit the excuses page listed below and investigate the failures, proceeding afterwards as per the StableReleaseUpdates policy regarding autopkgtest regressions [1].

https://people.canonical.com/~ubuntu-archive/proposed-migration/bionic/update_excuses.html#systemd

[1] https://wiki.ubuntu.com/StableReleaseUpdates#Autopkgtest_Regressions

Thank you!

[Dan Streetman (ddstreet)]

focal:

root@lp1878955-f:~# dpkg -l systemd|grep systemd
ii systemd 245.4-4ubuntu3.3 amd64 system and service manager
root@lp1878955-f:~# dhclient -i ens8
cmp: EOF on /tmp/tmp.4YGbdTC8iI which is empty

root@lp1878955-f:~# dpkg -l systemd|grep systemd
ii systemd 245.4-4ubuntu3.4 amd64 system and service manager
root@lp1878955-f:~# dhclient -i ens8
root@lp1878955-f:~#

[Dan Streetman (ddstreet)]

bionic:

root@lp1878955-b:~# dpkg -l systemd|grep systemd
ii systemd 237-3ubuntu10.43 amd64 system and service manager
root@lp1878955-b:~# dhclient -i ens8
cmp: EOF on /tmp/tmp.poVVjvvwPp which is empty

root@lp1878955-b:~# dpkg -l systemd|grep systemd
ii systemd 237-3ubuntu10.44 amd64 system and service manager
root@lp1878955-b:~# dhclient -i ens8
root@lp1878955-b:~#

[Launchpad Janitor (janitor)]

This bug was fixed in the package systemd - 245.4-4ubuntu3.4

---------------
systemd (245.4-4ubuntu3.4) focal; urgency=medium

  * d/p/lp1905245/0001-basic-cap-list-parse-print-numerical-capabilities.patch,
    d/p/lp1905245/0002-basic-capability-util-let-cap_last_cap-return-unsign.patch,
    d/p/lp1905245/0003-basic-cap-list-reduce-scope-of-variables.patch:
    - print number of unknown capabilities instead of failing
      (LP: #1905245)
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=5cd98102e16a6e4acc1444b10db3308d87930933
  * d/p/lp1890448-hwdb-Add-EliteBook-to-use-micmute-hotkey.patch:
    Add EliteBook to use micmute hotkey (LP: #1890448)
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=238c8c1a7b9d75f69bdeafb1d55f1faf00acb063
  * d/extra/dhclient-enter-resolved-hook:
    suppress output of cmp command in dhclient hook (LP: #1878955)
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=83df4fc182f8ffe87256f5d7c4b49cee5192529a
  * d/p/lp1905044-test-use-cap_last_cap-for-max-supported-cap-number-n.patch:
    test: use cap_last_cap() instead of capability_list_length()
    (LP: #1905044)
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=ff21f41e624d9e603f3be463846ce981a433842a
  * d/p/lp1903300/0001-network-VXLan-fix-adding-Group-address.patch,
    d/p/lp1903300/0002-network-VXLan-Add-support-for-remote-address.patch,
    d/p/lp1903300/0003-networkctl-Add-support-to-display-VXLan-remote-addre.patch:
    set vxlan multicast group when specified (LP: #1903300)
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=9deff4b7c5495dbe738561ca47daf3756df9fcde
  * d/p/lp1907306/0001-sd-dhcp-client-don-t-log-timeouts-if-already-expired.patch,
    d/p/lp1907306/0002-sd-dhcp-client-track-dhcp4-t1-t2-expire-times.patch,
    d/p/lp1907306/0003-sd-dhcp-client-add-RFC2131-retransmission-details.patch,
    d/p/lp1907306/0004-sd-dhcp-client-simplify-dhcp4-t1-t2-parsing.patch,
    d/p/lp1907306/0005-sd-dhcp-client-correct-dhcpv4-renew-rebind-retransmi.patch,
    d/p/lp1907306/0006-sd-dhcp-client-correct-retransmission-timeout-to-mat.patch,
    d/p/lp1907306/0007-test-network-increase-wait_online-timeout-to-handle-.patch,
    d/p/lp1907306/0008-sd-dhcp-client-fix-renew-rebind-timeout-calculation-.patch:
    Send correct number of dhcpv4 renew and rebind requests
    (LP: #1907306)
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=a73c51d0df284dcc38e6924d40eed810554bab2e
  * d/p/lp1902960-udev-re-assign-ID_NET_DRIVER-ID_NET_LINK_FILE-ID_NET.patch:
    Run net_setup_link on 'change' uevents (LP: #1902960)
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=ec7ba2358aa68d8d6276ed56ef91caafc287cecf
  * d/t/root-unittests:
    Remove any corrupt journal files (LP: #1881947)
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=5481fececdb3cb35ca7118598cad537681b5ff14

 -- Dan Streetman <email address hidden> Wed, 06 Jan 2021 15:47:39 -0500

[Łukasz Zemczak (sil2100)]

The verification of the Stable Release Update for systemd has completed successfully and the package is now being released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

[Launchpad Janitor (janitor)]

This bug was fixed in the package systemd - 237-3ubuntu10.44

---------------
systemd (237-3ubuntu10.44) bionic; urgency=medium

  * d/extra/dhclient-enter-resolved-hook:
    suppress output of cmp command in dhclient hook (LP: #1878955)
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=c5a2db69aafc7a3ab4e71bae44fd7ad9dd955c97
  * d/p/lp1905044/0001-capability-add-a-way-to-get-a-uint64_t-with-all-caps.patch,
    d/p/lp1905044/0002-test-use-cap_last_cap-for-max-supported-cap-number-n.patch:
    test: use cap_last_cap() instead of capability_list_length()
    (LP: #1905044)
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=34ebc6e28e63881d40c91c5839597acc2fdab546
  * d/p/lp1905245/0001-basic-cap-list-parse-print-numerical-capabilities.patch:
    print number of unknown capabilities instead of failing
    (LP: #1905245)
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=5ab225b7f731c6cf6b4655cb27c3a842150c4c1a
  * d/p/lp1907306/0001-sd-dhcp-client-don-t-log-timeouts-if-already-expired.patch,
    d/p/lp1907306/0002-sd-dhcp-client-track-dhcp4-t1-t2-expire-times.patch,
    d/p/lp1907306/0003-sd-dhcp-client-add-RFC2131-retransmission-details.patch,
    d/p/lp1907306/0004-sd-dhcp-client-simplify-dhcp4-t1-t2-parsing.patch,
    d/p/lp1907306/0005-sd-dhcp-client-correct-dhcpv4-renew-rebind-retransmi.patch,
    d/p/lp1907306/0008-sd-dhcp-client-fix-renew-rebind-timeout-calculation-.patch:
    Send correct number of dhcpv4 renew and rebind requests
    (LP: #1907306)
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=036230cac8232bf4f970e565c355ee1a82fc2ee6
  * d/t/root-unittests:
    Remove any corrupt journal files (LP: #1881947)
    https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/commit/?id=b284b93e40b6cb834bb40dd3db94850853ab5bb8

 -- Dan Streetman <email address hidden> Wed, 06 Jan 2021 16:04:25 -0500