Add util for checking installation permissions

doc/source/PreConfiguredSites.rst

@@ -757,6 +757,9 @@ The following instructions install a new spack environment on a pre-configured s
    # Create meta-modules for compiler, mpi, python
    spack stack setup-meta-modules
 
+   # Check permissions for systems where non-owning users/groups need access
+   ${SPACK_STACK_DIR}/util/check_permissions.sh
+
 .. note::
   You may want to capture the output from :code:`spack concretize` and :code:`spack install` comands in log files.
   For example:

doc/source/Utilities.rst

@@ -20,6 +20,14 @@ The utility located at util/show_duplicate_packages.py parses the output of ``sp
 
 The ``-d`` option shows only a list of the duplicates, as opposed to the default behavior, which is to show a print-out of all packages with colorized duplicates. In any case, the identification of any duplicates will yield a return code of 1. The ``-i`` option can be invoked multiple times to skip specific package names.
 
+.. _Permissions_Checker:
+
+------------------------------
+check_permissions.sh
+------------------------------
+
+The utility located at util/check_permissions.sh can be run inside any spack-stack environment directory intended for multiple users (i.e., on an HPC or cloud platform). It will return errors if the environment directory is inaccessible to non-owning users and groups (i.e., if o+rx not set), as well as if any directories or files have permissions that make them inaccessible to other users.
+
 .. _Acorn_Utilities:
 
 ------------------------------

util/check_permissions.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+# Run this utility inside a spack-stack environment directory to ensure that
+# permissions are set such that non-owning users/groups can use the
+# installation.
+
+path=$PWD
+
+# Check upstream hierarchy of current directory
+while [ $path != '/' ]; do
+  o_perms=$(stat $path --format="%A" | grep -o "...$")
+  if [ ${o_perms:0:1} != 'r' ]; then
+    echo "Path $path is not readable by non-owners; set o+r" 1>&2
+    iret=1
+  fi
+  if [ ${o_perms:2:3} != 'x' ]; then
+    echo "Path $path is not accessible by non-owners; set o+x" 1&>2
+    iret=1
+  fi
+  path=$(dirname $path)
+done
+
+# Check downstream hierarchy of current directory
+n_bad_perms=$(find \( -type d -a -not -perm -005 \) -o \( -type f -a -not -perm -004 \) | wc -l)
+if [ $n_bad_perms -gt 0 ]; then
+  echo "There are files under this hierarchy not accessible to non-owning users/groups."
+  echo "Use 'find \( -type d -a -not -perm -005 \) -o \( -type f -a -not -perm -004 \)' to identify them."
+  iret=1
+fi
+
+exit $iret