Package: opensysusers
Version: 0.7.3-2
Severity: serious
Tags: patch
User: helm...@debian.org
Usertags: dep17p3
Control: affects -1 + systemd
Hi,
opensysusers diverts /bin/systemd-sysusers. systemd has moved this file
to /usr/bin/systemd-sysusers in version 255~rc1-1. While this change is
not visible in an installation, the diversion no longer matches it. Thus
what ends up at systemd-sysusers now depends on the order of unpacks.
The diversion has become ineffective. This is a known problem category
and documented in DEP17[1] as P3.
Usually, the recommended mitigation for this kind of problem is
duplicating the diversion (M18) such that both /bin/systemd-sysusers and
/usr/bin/systemd-sysusers are diverted. I'm attaching a patch for this
approach, but I think this is not the preferred solution for this case.
I dug deeper as to why opensysusers would divert systemd-sysusers,
talked to systemd maintainers and Thomas Goirand and read about #947847
in the process. Given this background, I believe that the use of a
diversion is not a good solution and this was echoed by the CTTE
decision, which declined to overrule and considered diversion a
mechanism for experimentation. Three years later and with two stable
releases including opensysusers I hope we are past the experimentation
phase. The diversion setup bears a significant downside: While the API
existing API of the sysusers interface is relatively stable, systemd
keeps adding features and when systemd calls systemd-sysusers it wants
to be able to rely on its latest features. A diverted systemd-sysusers
may not provide what is needed here. Looking deeper into policy sections
7.4 and 7.5, the virtual package systemd-sysusers looks similar to
mail-transport-agent where each implementation
provides+conflicts+replaces mail-transport-agent. I think opensysusers
should do the same. Once doing so, the diversion (and thus this bug)
goes away entirely. The downside is that opensysusers and systemd are no
longer coinstallable. I'm also attaching a patch for this.
I caution that Thomas Goirand disagrees with this approach and
recommends that these packages remain coinstallable and that users may
choose the implementation. On the flip side, a user cannot choose to
have systemd as the provider of systemd-sysusers when opensysusers is
installed.
A possible compromise could be that opensysusers stops diverting
systemd-sysusers and installs the symbolic link without diversion such
that systemd becomes the preferred provider when coinstalled. It could
detect removal of systemd using file triggers and then reinstate the
link. Such a setup also requires little cooperation from systemd
maintainers, but it relies on an symbolic link that is completely
untracked by dpkg, so there is some fragility to be found here whereas
the conflict is conceptually simpler.
In any case, something needs to be done here. The latest systemd upload
now declares an unversioned conflict with opensysusers. It can become
versioned once opensysusers has addressed this bug in some way.
Helmut
[1] https://subdivi.de/~helmut/dep17.html
diff --minimal -Nru opensysusers-0.7.3/debian/changelog
opensysusers-0.7.3/debian/changelog
--- opensysusers-0.7.3/debian/changelog 2022-11-20 16:18:16.000000000 +0100
+++ opensysusers-0.7.3/debian/changelog 2023-11-07 08:38:13.000000000 +0100
@@ -1,3 +1,11 @@
+opensysusers (0.7.3-2.1) UNRELEASED; urgency=medium
+
+ * Non-maintainer upload.
+ * Duplicate diversion to mitigate DEP17 P3 via M18. (Closes: #-1)
+ * Move to /usr.
+
+ -- Helmut Grohne <hel...@subdivi.de> Tue, 07 Nov 2023 08:38:13 +0100
+
opensysusers (0.7.3-2) unstable; urgency=medium
* d/preinst: remove -u option.
diff --minimal -Nru opensysusers-0.7.3/debian/opensysusers.links
opensysusers-0.7.3/debian/opensysusers.links
--- opensysusers-0.7.3/debian/opensysusers.links 2022-11-20
16:11:31.000000000 +0100
+++ opensysusers-0.7.3/debian/opensysusers.links 2023-11-07
08:38:13.000000000 +0100
@@ -1 +1 @@
-/usr/bin/opensysusers-sysusers /bin/systemd-sysusers
+/usr/bin/opensysusers-sysusers /usr/bin/systemd-sysusers
diff --minimal -Nru opensysusers-0.7.3/debian/opensysusers.lintian-overrides
opensysusers-0.7.3/debian/opensysusers.lintian-overrides
--- opensysusers-0.7.3/debian/opensysusers.lintian-overrides 2022-11-20
16:11:31.000000000 +0100
+++ opensysusers-0.7.3/debian/opensysusers.lintian-overrides 2023-11-07
08:38:13.000000000 +0100
@@ -4,4 +4,6 @@
# Creating sysusers.d is intentional
opensysusers: package-contains-empty-directory [usr/lib/sysusers.d/]
# The manpage is provided by the systemd package
-opensysusers: no-manual-page [bin/systemd-sysusers]
+opensysusers: no-manual-page [usr/bin/systemd-sysusers]
+# DEP17 M18 not recognized by lintian
+opensysusers: diversion-for-unknown-file bin/systemd-sysusers [preinst:*]
diff --minimal -Nru opensysusers-0.7.3/debian/opensysusers.postrm
opensysusers-0.7.3/debian/opensysusers.postrm
--- opensysusers-0.7.3/debian/opensysusers.postrm 2022-11-20
16:15:39.000000000 +0100
+++ opensysusers-0.7.3/debian/opensysusers.postrm 2023-11-07
08:38:10.000000000 +0100
@@ -3,15 +3,30 @@
set -e
if [ "$1" = "remove" ] || [ "$1" = "abort-install" ] || [ "$1" = "disappear" ]
; then
- dpkg-divert --package opensysusers --remove --rename \
+ dpkg-divert --package opensysusers --remove --no-rename \
--divert /bin/systemd-sysusers.real /bin/systemd-sysusers
+ dpkg-divert --package opensysusers --remove --no-rename \
+ --divert /usr/bin/systemd-sysusers.real /usr/bin/systemd-sysusers
fi
if [ "abort-upgrade" = "$1" ] && dpkg --compare-versions "$2" lt 0.6-1; then
- dpkg-divert --package opensysusers --remove --rename \
+ dpkg-divert --package opensysusers --remove --no-rename \
--divert /bin/systemd-sysusers.real /bin/systemd-sysusers
fi
+if [ "$1" = abort-upgrade ] && dpkg --compare-versions "$2" lt 0.7.3-2.1~; then
+ dpkg-divert --package opensysusers --remove --no-rename \
+ --divert /usr/bin/systemd-sysusers.real /usr/bin/systemd-sysusers
+fi
+
+if [ "$1" = "remove" ] || [ "$1" = "abort-install" ] || [ "$1" = "disappear" ]
; then
+ for f in /usr/bin/systemd-sysusers /bin/systemd-sysusers; do
+ if [ -e "$DPKG_ROOT$f.real" ] && ! [ -e "$DPKG_ROOT$f" ]; then
+ mv "$DPKG_ROOT$f.real" "$DPKG_ROOT$f"
+ fi
+ done
+fi
+
#DEBHELPER#
exit 0
diff --minimal -Nru opensysusers-0.7.3/debian/opensysusers.preinst
opensysusers-0.7.3/debian/opensysusers.preinst
--- opensysusers-0.7.3/debian/opensysusers.preinst 2022-11-20
16:11:53.000000000 +0100
+++ opensysusers-0.7.3/debian/opensysusers.preinst 2023-11-07
08:35:14.000000000 +0100
@@ -7,10 +7,23 @@
fi
if [ upgrade != "$1" ] || dpkg --compare-versions "$2" lt 0.6-1; then
- dpkg-divert --package opensysusers --add --rename \
+ dpkg-divert --package opensysusers --add --no-rename \
--divert /bin/systemd-sysusers.real /bin/systemd-sysusers
fi
+if [ upgrade != "$1" ] || dpkg --compare-versions "$2" lt 0.7.3-2.1~; then
+ dpkg-divert --package opensysusers --add --no-rename \
+ --divert /usr/bin/systemd-sysusers.real /usr/bin/systemd-sysusers
+fi
+
+if [ upgrade != "$1" ]; then
+ for f in /usr/bin/systemd-sysusers /bin/systemd-sysusers; do
+ if [ -e "$DPKG_ROOT$f" ] && ! [ -e "$DPKG_ROOT$f.real" ]; then
+ mv "$DPKG_ROOT$f" "$DPKG_ROOT$f.real"
+ fi
+ done
+fi
+
#DEBHELPER#
exit 0
diff --minimal -Nru opensysusers-0.7.3/debian/changelog
opensysusers-0.7.3/debian/changelog
--- opensysusers-0.7.3/debian/changelog 2022-11-20 16:18:16.000000000 +0100
+++ opensysusers-0.7.3/debian/changelog 2023-11-07 16:34:41.000000000 +0100
@@ -1,3 +1,10 @@
+opensysusers (0.7.3-2.1) UNRELEASED; urgency=medium
+
+ * Non-maintainer upload.
+ * Declare Conflicts+Replaces systemd-sysusers. (Closes: #-1)
+
+ -- Helmut Grohne <hel...@subdivi.de> Tue, 07 Nov 2023 16:34:41 +0100
+
opensysusers (0.7.3-2) unstable; urgency=medium
* d/preinst: remove -u option.
diff --minimal -Nru opensysusers-0.7.3/debian/control
opensysusers-0.7.3/debian/control
--- opensysusers-0.7.3/debian/control 2022-11-20 16:11:31.000000000 +0100
+++ opensysusers-0.7.3/debian/control 2023-11-07 16:30:08.000000000 +0100
@@ -14,7 +14,9 @@
Homepage: https://github.com/cromerc/opensysusers.git
Package: opensysusers
+Conflicts: systemd-sysusers
Provides: systemd-sysusers
+Replaces: systemd-sysusers
Architecture: all
Depends:
${misc:Depends},
diff --minimal -Nru opensysusers-0.7.3/debian/opensysusers.postinst
opensysusers-0.7.3/debian/opensysusers.postinst
--- opensysusers-0.7.3/debian/opensysusers.postinst 1970-01-01
01:00:00.000000000 +0100
+++ opensysusers-0.7.3/debian/opensysusers.postinst 2023-11-07
16:33:50.000000000 +0100
@@ -0,0 +1,12 @@
+#!/bin/sh
+
+set -e
+
+if [ "$1" = configure ] && dpkg --compare-versions "$2" lt-nl 0.7.3-2.1~; then
+ dpkg-divert --package opensysusers --remove --no-rename \
+ --divert /bin/systemd-sysusers.real /bin/systemd-sysusers
+fi
+
+#DEBHELPER#
+
+exit 0
diff --minimal -Nru opensysusers-0.7.3/debian/opensysusers.postrm
opensysusers-0.7.3/debian/opensysusers.postrm
--- opensysusers-0.7.3/debian/opensysusers.postrm 2022-11-20
16:15:39.000000000 +0100
+++ opensysusers-0.7.3/debian/opensysusers.postrm 1970-01-01
01:00:00.000000000 +0100
@@ -1,17 +0,0 @@
-#!/bin/sh
-
-set -e
-
-if [ "$1" = "remove" ] || [ "$1" = "abort-install" ] || [ "$1" = "disappear" ]
; then
- dpkg-divert --package opensysusers --remove --rename \
- --divert /bin/systemd-sysusers.real /bin/systemd-sysusers
-fi
-
-if [ "abort-upgrade" = "$1" ] && dpkg --compare-versions "$2" lt 0.6-1; then
- dpkg-divert --package opensysusers --remove --rename \
- --divert /bin/systemd-sysusers.real /bin/systemd-sysusers
-fi
-
-#DEBHELPER#
-
-exit 0
diff --minimal -Nru opensysusers-0.7.3/debian/opensysusers.preinst
opensysusers-0.7.3/debian/opensysusers.preinst
--- opensysusers-0.7.3/debian/opensysusers.preinst 2022-11-20
16:11:53.000000000 +0100
+++ opensysusers-0.7.3/debian/opensysusers.preinst 2023-11-07
16:30:39.000000000 +0100
@@ -6,11 +6,6 @@
update-alternatives --remove-all sysusers
fi
-if [ upgrade != "$1" ] || dpkg --compare-versions "$2" lt 0.6-1; then
- dpkg-divert --package opensysusers --add --rename \
- --divert /bin/systemd-sysusers.real /bin/systemd-sysusers
-fi
-
#DEBHELPER#
exit 0
