intel-oneapi packages: support root installs (#23401)

When installing OneAPI packages as root (e.g. in a container), the
installer places cache files in /var/intel/installercache that
interfere with future Spack installs. This ensures that when
running an installation as a root user that this is removed.

lib/spack/spack/build_systems/oneapi.py

@@ -7,6 +7,8 @@
 
 """
 
+import getpass
+import shutil
 from sys import platform
 from os.path import basename, dirname, isdir
 
@@ -47,6 +49,22 @@ def install(self, spec, prefix, installer_path=None):
             installer_path = basename(self.url_for_version(spec.version))
 
         if platform == 'linux':
+            # Intel installer assumes and enforces that all components
+            # are installed into a single prefix. Spack wants to
+            # install each component in a separate prefix. The
+            # installer mechanism is implemented by saving install
+            # information in a directory called installercache for
+            # future runs. The location of the installercache depends
+            # on the userid. For root it is always in /var/intel. For
+            # non-root it is in $HOME/intel.
+            #
+            # The method for preventing this install from interfering
+            # with other install depends on the userid. For root, we
+            # delete the installercache before and after install. For
+            # non root we redefine the HOME environment variable.
+            if getpass.getuser() == 'root':
+                shutil.rmtree('/var/intel/installercache', ignore_errors=True)
+
             bash = Executable('bash')
 
             # Installer writes files in ~/intel set HOME so it goes to prefix
@@ -57,6 +75,9 @@ def install(self, spec, prefix, installer_path=None):
                  '--eula', 'accept',
                  '--install-dir', prefix)
 
+            if getpass.getuser() == 'root':
+                shutil.rmtree('/var/intel/installercache', ignore_errors=True)
+
         # Some installers have a bug and do not return an error code when failing
         if not isdir(join_path(prefix, self.component_dir)):
             raise RuntimeError('install failed')