RFC: bee-mxqsub: Run only install and packaging under fakeroot

scripts/bee-mxqsub

@@ -59,6 +59,9 @@ buildroot=
 # like 0, so beerc picks bee's default for root, /src/mariux/beeroot, which is
 # where the artifacts belong. Pass --repository to build into a private tree.
 repository=
+# beesh --fakeroot runs only the install and packaging under fakeroot, and
+# configures and builds with the real UID; see the job phase. Without it, the
+# whole of beesh runs under fakeroot.
 use_fakeroot=1
 keep_buildroot=0
 # The staging directory has to be readable from the cluster nodes, so it must
@@ -112,7 +115,9 @@ Options:
                           pull a bee-file away from the running job
                           (default: /scratch/tmp/bee-mxqsub-\$USER)
       --no-stage          build from the bee-files in the repository
-      --fakeroot          call beesh under fakeroot          (default)
+      --fakeroot          install and package under fakeroot, configure and
+                          build without it if beesh has --fakeroot, else
+                          call all of beesh under fakeroot   (default)
       --no-fakeroot       call beesh without fakeroot
       --overlay           install each package into an overlay, so that the
                           following bee-files find it, and build in a sandbox
@@ -410,11 +415,6 @@ if (( run_job )); then
 	echo "=== buildroot:  ${buildroot}"
 	echo "=== repository: ${repository:-<beerc default>}"
 	echo "=== makeflags:  ${makeflags}"
-	if (( use_fakeroot )); then
-		echo "=== fakeroot:   yes"
-	else
-		echo "=== fakeroot:   no"
-	fi
 	if (( overlay )); then
 		echo "=== overlay:    ${overlay_root} over ${overlay_dirs[*]}"
 	else
@@ -437,6 +437,24 @@ if (( run_job )); then
 		export "${assignment?}"
 	done
 
+	# Under fakeroot, the stat, chmod and chown calls of every build process
+	# go through the one faked daemon, which made the Firefox build take 17:37
+	# instead of 11:34. Only installing and packaging need the fake root, and
+	# beesh --fakeroot confines it to them. Older beesh versions lack the
+	# option and get the whole of beesh run under fakeroot as before. Ask
+	# only now, as --env may have set PATH to another bee.
+	beesh_fakeroot=0
+	if (( use_fakeroot )); then
+		if beesh --help 2>/dev/null | grep -q -e '--fakeroot'; then
+			beesh_fakeroot=1
+			echo "=== fakeroot:   install and packaging only (beesh --fakeroot)"
+		else
+			echo "=== fakeroot:   all of beesh (beesh lacks --fakeroot)"
+		fi
+	else
+		echo "=== fakeroot:   no"
+	fi
+
 	# mxqd hands a job the usual soft limit of 1024 open files while the hard
 	# limit is higher, and raising the soft limit to the hard one needs no
 	# privileges. Every process of every build inherits it, fuse-overlayfs
@@ -500,6 +518,17 @@ if (( run_job )); then
 	else
 		config=$(bee --print-config)
 	fi
+	# beesh --fakeroot reads the configuration with the real UID, for which
+	# beerc picks the private repository below ~/.local and the user's
+	# package database and cache instead of root's. Hand it the paths of
+	# root's configuration, as a beesh running under fakeroot would use.
+	if (( beesh_fakeroot )) && ! (( overlay )); then
+		for var in BEE_REPOSITORY_PREFIX BEE_METADIR BEE_CACHEDIR; do
+			value=$(sed -n "s/^${var}=//p" <<< "${config}")
+			[ -n "${value}" ] || die "cannot read ${var} from bee --print-config"
+			export "${var}=${value}"
+		done
+	fi
 	pkgdir=$(sed -n 's/^BEE_PKGDIR=//p' <<< "${config}")
 	[ -n "${pkgdir}" ] || die "cannot read BEE_PKGDIR from bee --print-config"
 	mkdir -p "${pkgdir}" 2>/dev/null
@@ -539,7 +568,9 @@ if (( run_job )); then
 		# A .be0/.bee is a beesh script: its mee_* hooks are called by
 		# beesh, so running it with plain bash only defines the functions
 		# and builds nothing.
-		if (( use_fakeroot )); then
+		if (( beesh_fakeroot )); then
+			${sandbox[@]+"${sandbox[@]}"} beesh --fakeroot "${beesh_args[@]}" "${beefile}"
+		elif (( use_fakeroot )); then
 			${sandbox[@]+"${sandbox[@]}"} fakeroot beesh "${beesh_args[@]}" "${beefile}"
 		else
 			${sandbox[@]+"${sandbox[@]}"} beesh "${beesh_args[@]}" "${beefile}"