Move pid, stacks from envsetup.sh to dedicated scripts.

Make it so that these can be used in other scripts by moving them from
functions defined in envsetup.sh to standalone scripts.

Test: stacks zygote64
Change-Id: I55ba76b248c54d9193fb019b7f4aca2f4c3a05bd
diff --git a/scripts/stacks b/scripts/stacks
new file mode 100755
index 0000000..7f4bb5a
--- /dev/null
+++ b/scripts/stacks
@@ -0,0 +1,43 @@
+#!/bin/bash
+# Copyright (C) 2018 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.
+
+# Get backtraces for a process.
+if [[ $1 =~ ^[0-9]+$ ]] ; then
+    PID="$1"
+elif [ "$1" ] ; then
+    PIDLIST="$(pid $1)"
+    if [[ $PIDLIST =~ ^[0-9]+$ ]] ; then
+        PID="$PIDLIST"
+    elif [ "$PIDLIST" ] ; then
+        echo "more than one process: $1"
+    else
+        echo "no such process: $1"
+    fi
+else
+    echo "usage: stacks [pid|process name]"
+fi
+
+if [ "$PID" ] ; then
+    # Use `debuggerd -j` on java processes.
+    if adb shell readlink /proc/$PID/exe | egrep -q '^/system/bin/app_process' ; then
+        # But not the zygote.
+        if ! adb shell cat /proc/$PID/cmdline | egrep -q '^zygote'; then
+            adb shell debuggerd -j $PID
+            exit $?
+        fi
+    fi
+
+    adb shell debuggerd -b $PID
+fi