file-systems: Spawn a REPL only when interaction is possible.

Fixes <https://bugs.gnu.org/23697>.
Reported by Jan Nieuwenhuizen <janneke@gnu.org>.

* gnu/build/file-systems.scm (check-file-system): Call 'start-repl' only
if current-input-port passes 'isatty?'.
* gnu/services/shepherd.scm (shepherd-configuration-file): After
'for-each' expression, call 'redirect-port'.
* gnu/tests/base.scm (run-basic-test)["stdin is /dev/null"]: New test.

1 files changed, 15 insertions, 0 deletions

diff --git a/gnu/tests/base.scm b/gnu/tests/base.scm
index 03392cef38..8d4e218a8f 100644
--- a/gnu/tests/base.scm
+++ b/gnu/tests/base.scm
@@ -123,6 +123,21 @@ initialization step, such as entering a LUKS passphrase."
                          #f))))
              marionette))
 
+          (test-eq "stdin is /dev/null"
+            'eof
+            ;; Make sure services can no longer read from stdin once the
+            ;; system has booted.
+            (marionette-eval
+             `(begin
+                (use-modules (gnu services herd))
+                (start 'user-processes)
+                ((@@ (gnu services herd) eval-there)
+                 '(let ((result (read (current-input-port))))
+                    (if (eof-object? result)
+                        'eof
+                        result))))
+             marionette))
+
           (test-assert "shell and user commands"
             ;; Is everything in $PATH?
             (zero? (marionette-eval '(system "