Add a script to build multiple SELinux targets.

This script will build the SELinux policy for multiple targets in parallel.

To use it, run:
./build_policies.sh <Android root directory> <output directory> [specific targets to build]

If you do not pass any individual targets, it will build all targets it can find.

It will print out the list of failing targets.  You can open up the corresponding log file in the output directory to see the exact errors.

This script is still a work in progress.  It currently cannot discover all build targets (it misses ones "lunch" does not list).

Bug: 33463570
Test: Ran script to build multiple targets with and without failures.
Change-Id: Iee8ccf4da38e5eb7ce2034431613fe10c65696ab

tools/README

@@ -3,6 +3,15 @@ which are used in building and validating the policy and others are
 available for help in auditing and analyzing policy.  The tools are
 described further below.
 
+build_policies.sh
+   A tool to build SELinux policy for multiple targets in parallel.
+   This is useful for quickly testing a new test or neverallow rule
+   on multiple targets.
+
+   Usage:
+   ./build_policies.sh ~/android/master ~/tmp/build_policies
+   ./build_policies.sh ~/android/master ~/tmp/build_policies sailfish-eng walleye-eng
+
 checkfc
    A utility for checking the validity of a file_contexts or a
    property_contexts configuration file.  Used as part of the policy

tools/build_policies.sh

@@ -0,0 +1,90 @@
+#!/bin/bash
+
+# Ensure that GNU parallel is installed.
+# We use this to build multiple targets at the same time.
+if [[ -z $(command -v parallel) ]]; then
+  echo "Please install GNU Parallel."
+  exit
+fi
+
+if [[ $# -lt 2 ]]; then
+  echo "Usage: $0 <Android root directory> <output directory> [specific targets to build]"
+  exit
+fi
+
+android_root_dir=$1
+export out_dir=$2
+shift 2
+all_targets="$@"
+
+echo "Android tree: $android_root_dir"
+echo "Output directory: $out_dir"
+
+mkdir -p $out_dir
+
+cd $android_root_dir
+source build/envsetup.sh > /dev/null
+
+# Collect the list of targets by parsing the output of lunch.
+# TODO: This misses some targets.
+if [[ "$all_targets" = "" ]]; then
+  all_targets=`lunch 2>/dev/null <<< _ | grep "[0-9]" | sed 's/^.* //'`
+fi
+
+# Clean up targets by replacing eng with userdebug using non-aosp variants.
+declare -A targets_map
+for target in $all_targets; do
+  targets_map[$target]=$target
+done
+targets=""
+for target in $all_targets; do
+  clean_target=$(echo $target | sed 's/-eng/-userdebug/' | sed 's/aosp_//')
+  if [[ $clean_target != $target ]] && [[ ${targets_map[$clean_target]} == $clean_target ]]; then
+    echo "Ignoring $target in favor of $clean_target"
+  else
+    if [[ -z $targets ]]; then
+      targets=$target
+    else
+      targets="$targets $target"
+    fi
+  fi
+done
+
+# Calculate the number of targets to build at once.
+# This heuristic could probably be improved.
+cores=$(nproc --all)
+num_targets=$(echo "$targets" | sed 's/ /\n/g' | wc -l)
+parallel_jobs=$(expr $cores / 2)
+if [[ $num_targets -lt $parallel_jobs ]]; then
+  export mmma_jobs=$(expr $cores / $num_targets \* 2)
+else
+  export mmma_jobs=4
+fi
+
+echo "$num_targets target(s): $(echo $targets | paste -sd' ')"
+
+compile_target () {
+  target=$1
+  source build/envsetup.sh > /dev/null
+  lunch $target &> /dev/null
+  # Some targets can't lunch properly.
+  if [ $? -ne 0 ]; then
+    echo "$target cannot be lunched"
+    return 1
+  fi
+  my_out_file="$out_dir/log.$target"
+  rm -f $my_out_file
+  # Build the policy.
+  OUT_DIR=$out_dir/out.$target mmma -j$mmma_jobs system/sepolicy &>> $my_out_file
+  if [ $? -ne 0 ]; then
+    echo "$target failed to build"
+    return 2
+  fi
+  return 0
+}
+export -f compile_target
+
+parallel --no-notice -j $parallel_jobs --bar --joblog $out_dir/joblog compile_target ::: $targets
+
+echo "Failed to lunch: $(grep "\s1\s0\scompile_target" $out_dir/joblog | sed 's/^.* //' | sort | paste -sd' ')"
+echo "Failed to build: $(grep "\s2\s0\scompile_target" $out_dir/joblog | sed 's/^.* //' | sort | paste -sd' ')"