diff --git a/OWNERS b/OWNERS
index 5c7f5adff2..57d89947b3 100644
--- a/OWNERS
+++ b/OWNERS
@@ -3,6 +3,7 @@ include platform/build/soong:/OWNERS
 # Since this file affects all Android developers, lock it down. There is still
 # round the world timzeone coverage.
 per-file envsetup.sh = joeo@google.com, jingwen@google.com, lberki@google.com
+per-file shell_utils.sh = joeo@google.com, jingwen@google.com, lberki@google.com
 
 # Finalization scripts
 per-file finalize* = smoreland@google.com, alexbuy@google.com
diff --git a/envsetup.sh b/envsetup.sh
index 49908003cf..a30f6bd278 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -1,3 +1,55 @@
+# Copyright (C) 2022 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# gettop is duplicated here and in shell_utils.mk, because it's difficult
+# to find shell_utils.make without it for all the novel ways this file can be
+# sourced.  Other common functions should only be in one place or the other.
+function _gettop_once
+{
+    local TOPFILE=build/make/core/envsetup.mk
+    if [ -n "$TOP" -a -f "$TOP/$TOPFILE" ] ; then
+        # The following circumlocution ensures we remove symlinks from TOP.
+        (cd "$TOP"; PWD= /bin/pwd)
+    else
+        if [ -f $TOPFILE ] ; then
+            # The following circumlocution (repeated below as well) ensures
+            # that we record the true directory name and not one that is
+            # faked up with symlink names.
+            PWD= /bin/pwd
+        else
+            local HERE=$PWD
+            local T=
+            while [ \( ! \( -f $TOPFILE \) \) -a \( "$PWD" != "/" \) ]; do
+                \cd ..
+                T=`PWD= /bin/pwd -P`
+            done
+            \cd "$HERE"
+            if [ -f "$T/$TOPFILE" ]; then
+                echo "$T"
+            fi
+        fi
+    fi
+}
+T=$(_gettop_once)
+if [ ! "$T" ]; then
+    echo "Couldn't locate the top of the tree. Always source build/envsetup.sh from the root of the tree." >&2
+    return 1
+fi
+IMPORTING_ENVSETUP=true source $T/build/make/shell_utils.sh
+
+
+# Help
 function hmm() {
 cat <<EOF
 
@@ -928,33 +980,6 @@ function banchan()
     destroy_build_var_cache
 }
 
-function gettop
-{
-    local TOPFILE=build/make/core/envsetup.mk
-    if [ -n "$TOP" -a -f "$TOP/$TOPFILE" ] ; then
-        # The following circumlocution ensures we remove symlinks from TOP.
-        (cd "$TOP"; PWD= /bin/pwd)
-    else
-        if [ -f $TOPFILE ] ; then
-            # The following circumlocution (repeated below as well) ensures
-            # that we record the true directory name and not one that is
-            # faked up with symlink names.
-            PWD= /bin/pwd
-        else
-            local HERE=$PWD
-            local T=
-            while [ \( ! \( -f $TOPFILE \) \) -a \( "$PWD" != "/" \) ]; do
-                \cd ..
-                T=`PWD= /bin/pwd -P`
-            done
-            \cd "$HERE"
-            if [ -f "$T/$TOPFILE" ]; then
-                echo "$T"
-            fi
-        fi
-    fi
-}
-
 # TODO: Merge into gettop as part of launching multitree
 function multitree_gettop
 {
diff --git a/shell_utils.sh b/shell_utils.sh
new file mode 100644
index 0000000000..9de5a504e5
--- /dev/null
+++ b/shell_utils.sh
@@ -0,0 +1,74 @@
+# Copyright (C) 2022 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+function gettop
+{
+    local TOPFILE=build/make/core/envsetup.mk
+    # The ${TOP-} expansion allows this to work even with set -u
+    if [ -n "${TOP:-}" -a -f "${TOP:-}/$TOPFILE" ] ; then
+        # The following circumlocution ensures we remove symlinks from TOP.
+        (cd "$TOP"; PWD= /bin/pwd)
+    else
+        if [ -f $TOPFILE ] ; then
+            # The following circumlocution (repeated below as well) ensures
+            # that we record the true directory name and not one that is
+            # faked up with symlink names.
+            PWD= /bin/pwd
+        else
+            local HERE=$PWD
+            local T=
+            while [ \( ! \( -f $TOPFILE \) \) -a \( "$PWD" != "/" \) ]; do
+                \cd ..
+                T=`PWD= /bin/pwd -P`
+            done
+            \cd "$HERE"
+            if [ -f "$T/$TOPFILE" ]; then
+                echo "$T"
+            fi
+        fi
+    fi
+}
+
+# Sets TOP, or if the root of the tree can't be found, prints a message and
+# exits.  Since this function exits, it should not be called from functions
+# defined in envsetup.sh.
+if [ -z "${IMPORTING_ENVSETUP:-}" ] ; then
+function require_top
+{
+    TOP=$(gettop)
+    if [[ ! $TOP ]] ; then
+        echo "Can not locate root of source tree. $(basename $0) must be run from within the Android source tree." >&2
+        exit 1
+    fi
+}
+fi
+
+function getoutdir
+{
+    local top=$(gettop)
+    local out_dir="${OUT_DIR:-}"
+    if [[ -z "${out_dir}" ]]; then
+        if [[ -n "${OUT_DIR_COMMON_BASE:-}" && -n "${top}" ]]; then
+            out_dir="${OUT_DIR_COMMON_BASE}/$(basename ${top})"
+        else
+            out_dir="out"
+        fi
+    fi
+    if [[ "${out_dir}" != /* ]]; then
+        out_dir="${top}/${out_dir}"
+    fi
+    echo "${out_dir}"
+}
+
+