9 files changed, 114 insertions, 8 deletions
diff --git a/debian/base-files.dirs b/debian/base-files.dirs
index b646146..d0769e4 100644
--- a/debian/base-files.dirs
+++ b/debian/base-files.dirs
@@ -1,4 +1,3 @@
-bin
 boot
 dev
 etc
@@ -8,19 +7,14 @@ etc/profile.d
 etc/skel
 etc/update-motd.d
 home
-lib
 proc
 root
 run
-sbin
 sys
 tmp
 usr
-usr/bin
 usr/games
 usr/include
-usr/lib
-usr/sbin
 usr/share
 usr/share/base-files
 usr/share/common-licenses
diff --git a/debian/base-files.lintian-overrides b/debian/base-files.lintian-overrides
index 691e9e6..e65cf1d 100644
--- a/debian/base-files.lintian-overrides
+++ b/debian/base-files.lintian-overrides
@@ -20,3 +20,16 @@ base-files: extra-license-file [usr/share/common-licenses/GPL-3]
 base-files: extra-license-file [usr/share/common-licenses/LGPL-2]
 base-files: extra-license-file [usr/share/common-licenses/LGPL-2.1]
 base-files: extra-license-file [usr/share/common-licenses/LGPL-3]
+#
+# These links really should be relative.
+#
+base-files: relative-symlink usr/bin [bin]
+base-files: relative-symlink usr/lib [lib]
+base-files: relative-symlink usr/lib64 [lib64]
+base-files: relative-symlink usr/libx32 [libx32]
+base-files: relative-symlink usr/sbin [sbin]
+#
+# We need these for the relevant architectures.
+#
+base-files: non-multi-arch-lib-dir [usr/lib64/]
+base-files: non-multi-arch-lib-dir [usr/libx32/]
diff --git a/debian/changelog b/debian/changelog
index cb72d36..43086e5 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,10 @@
+base-files (13.3) unstable; urgency=medium
+
+  [ Helmut Grohne ]
+  * DEP17: Install /usr-merge aliasing symlinks. Closes: #1064459.
+
+ -- Santiago Vila <sanvila@debian.org>  Thu, 06 Jun 2024 00:35:00 +0200
+
 base-files (13.2) unstable; urgency=medium
 
   * Document that /etc/profile is not a conffile anymore. Closes: #868095.
diff --git a/debian/clean b/debian/clean
index e69de29..b4ac698 100644
--- a/debian/clean
+++ b/debian/clean
@@ -0,0 +1 @@
+debian/triggers
diff --git a/debian/control b/debian/control
index d4bad8a..942fed8 100644
--- a/debian/control
+++ b/debian/control
@@ -7,7 +7,7 @@ Build-Depends: debhelper-compat (= 13), debhelper (>= 13.10~)
 Rules-Requires-Root: binary-targets
 
 Package: base-files
-Provides: base
+Provides: base, usr-is-merged
 Architecture: any
 Pre-Depends: awk
 Depends: ${misc:Depends}
diff --git a/debian/postinst b/debian/postinst
index 2708d17..e1ad3a4 100644
--- a/debian/postinst
+++ b/debian/postinst
@@ -108,4 +108,26 @@ if [ "$1" = "configure" ] && [ "$2" != "" ]; then
   fi
 fi
 
+rtlddir="#USR_MERGE_RTLDLIB#"
+if [ "$1" = "configure" ] && [ -n "$rtlddir" ]; then
+  # Remove temporary DEP17 M4 diversion added by glibc.
+  dpkg-divert --quiet --package base-files --remove --no-rename --divert "/.$rtlddir.usr-is-merged" "/$rtlddir"
+fi
+
+if [ "$1" = "configure" ] || [ "$1" = "triggered" ]; then
+  for d in #USR_MERGE_MULTILIB#; do
+    if [ -d "$DPKG_ROOT/usr/$d" ]; then
+      if [ -L "$DPKG_ROOT/$d" ]; then
+        :
+      elif [ -d "$DPKG_ROOT/$d" ]; then
+        echo "Warning: /$d is not a symlink, but should be." 1>&2
+      else
+        ln -s "usr/$d" "$DPKG_ROOT/$d"
+      fi
+    elif [ -L "$DPKG_ROOT/$d" ]; then
+      rm "$DPKG_ROOT/$d"
+    fi
+  done
+fi
+
 #DEBHELPER#
diff --git a/debian/postrm b/debian/postrm
new file mode 100644
index 0000000..402c738
--- /dev/null
+++ b/debian/postrm
@@ -0,0 +1,11 @@
+#!/bin/sh
+set -e
+
+if [ "$1" = "remove" ]; then
+  for d in #USR_MERGE_MULTILIB#; do
+    # Remove DEP17 M4 protective diversions
+    dpkg-divert --quiet --package base-files --remove --no-rename --divert "/.$d.usr-is-merged" "/$d"
+  done
+fi
+
+#DEBHELPER#
diff --git a/debian/preinst b/debian/preinst
new file mode 100644
index 0000000..b657de5
--- /dev/null
+++ b/debian/preinst
@@ -0,0 +1,32 @@
+#!/bin/sh
+set -e
+
+if [ "$1" = "install" ] || [ "$1" = "upgrade" ]; then
+  for d in bin lib lib32 lib64 libo32 lib64 sbin; do
+    if [ -d "$DPKG_ROOT/$d" ] && [ ! -L "$DPKG_ROOT/$d" ]; then
+      cat <<EOF
+
+
+******************************************************************************
+*
+* The base-files package cannot be installed because this system has a
+* split /usr.
+*
+* Please install the usrmerge package to convert this system to merged-/usr.
+*
+* For more information please read https://wiki.debian.org/UsrMerge.
+*
+******************************************************************************
+
+
+EOF
+      exit 1
+    fi
+  done
+  for d in #USR_MERGE_MULTILIB#; do
+    # Install DEP17 M4 protective diversions
+    dpkg-divert --quiet --package base-files --add --no-rename --divert "/.$d.usr-is-merged" "/$d"
+  done
+fi
+
+#DEBHELPER#
diff --git a/debian/rules b/debian/rules
index 05dfb39..17ad36f 100755
--- a/debian/rules
+++ b/debian/rules
@@ -1,5 +1,7 @@
 #!/usr/bin/make -f
 
+include /usr/share/dpkg/architecture.mk
+
 OSNAME = "GNU/`uname | sed -e 's/GNU\///'`"
 ifeq ($(DEB_HOST_GNU_SYSTEM),linux)
   OSNAME=GNU/Linux
@@ -11,6 +13,14 @@ endif
 VENDORFILE = debian
 DESTDIR = debian/base-files
 
+ifneq (,$(filter $(DEB_HOST_ARCH),amd64 loong64 mips64el ppc64 ppc64el sparc64))
+  USR_MERGE_RTLDLIB = lib64
+else ifneq (,$(filter $(DEB_HOST_ARCH),x32))
+  USR_MERGE_RTLDLIB = libx32
+endif
+USR_MERGE = bin lib sbin $(USR_MERGE_RTLDLIB)
+USR_MERGE_MULTILIB = $(filter-out $(USR_MERGE),lib32 lib64 libo32 libx32)
+
 %:
 	dh $@
 
@@ -19,6 +29,15 @@ execute_after_dh_clean:
 
 override_dh_auto_build:
 	sh debian/check-md5sum-etc profile
+	set -e; { \
+	  echo "# Triggers for creating multilib aliasing symlinks on demand"; \
+	  for d in $(USR_MERGE_MULTILIB); do \
+	    echo "interest-noawait /usr/$$d"; \
+	  done; \
+	} > debian/triggers
+
+execute_after_dh_installdirs:
+	dh_installdirs $(foreach d,$(USR_MERGE),usr/$(d))
 
 override_dh_auto_install:
 	install -p -m 644 etc/*      $(DESTDIR)/etc
@@ -42,6 +61,10 @@ override_dh_installchangelogs:
 
 override_dh_link:
 	dh_link -X os-release
+	# We want these links to be relative, so we cannot use dh_link.
+	set -e; for d in $(USR_MERGE); do \
+	  ln -s usr/$$d debian/base-files/$$d; \
+	done
 
 override_dh_compress:
 	dh_compress -X README
@@ -55,4 +78,7 @@ override_dh_fixperms:
 	cd debian/base-files && chmod 700 root
 
 override_dh_installdeb:
-	dh_installdeb -DVENDORFILE=$(VENDORFILE)
+	dh_installdeb \
+	  '-DVENDORFILE=$(VENDORFILE)' \
+	  '-DUSR_MERGE_MULTILIB=$(USR_MERGE_MULTILIB)' \
+	  '-DUSR_MERGE_RTLDLIB=$(USR_MERGE_RTLDLIB)'