tests: pam-limits: Confirm actual ulimits are installed.

This revised system test is superior to the one accepted when #61744 was
closed because it confirms whether the configured limits are actually being
enforced upon login.

The previous test merely validated the serialization of one particular config
in the config file.

* gnu/tests/pam.scm (pam-limits-service): Revise test to confirm limits on
login.
(%test-pam-limits)[description]: Update.
(%test-pam-limits-deprecated): Remove.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

gnu/tests/pam.scm

@@ -1,5 +1,6 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2023 Bruno Victal <mirai@makinata.eu>
+;;; Copyright © 2023 Felix Lechner <felix.lechner@lease-up.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -25,8 +26,7 @@
   #:use-module (gnu system vm)
   #:use-module (guix gexp)
   #:use-module (ice-9 format)
-  #:export (%test-pam-limits
+  #:export (%test-pam-limits))
-            %test-pam-limits-deprecated))
 
 
 ;;;
@@ -35,26 +35,29 @@
 
 (define pam-limit-entries
   (list
-   (pam-limits-entry "@realtime" 'both 'rtprio 99)
+   ;; make sure the limits apply to root (uid 0)
-   (pam-limits-entry "@realtime" 'both 'memlock 'unlimited)))
+   (pam-limits-entry ":0" 'both 'rtprio 99)               ;default is 0
+   (pam-limits-entry ":0" 'both 'memlock 'unlimited)))    ;default is 8192 kbytes
 
 (define (run-test-pam-limits config)
   "Run tests in a os with pam-limits-service-type configured."
   (define os
     (marionette-operating-system
      (simple-operating-system
-      (service pam-limits-service-type config))))
+      (service pam-limits-service-type config))
+     #:imported-modules '((gnu services herd))))
 
   (define vm
     (virtual-machine os))
 
-  (define name (format #f "pam-limit-service~:[~;-deprecated~]"
+  (define name "pam-limits-service")
-                       (file-like? config)))
 
   (define test
-    (with-imported-modules '((gnu build marionette))
+    (with-imported-modules '((gnu build marionette)
+                             (guix build syscalls))
       #~(begin
           (use-modules (gnu build marionette)
+                       (guix build syscalls)
                        (srfi srfi-64))
 
           (let ((marionette (make-marionette (list #$vm))))
@@ -63,18 +66,32 @@
 
             (test-begin #$name)
 
-            (test-assert "/etc/security/limits.conf ready"
+            (test-equal "log in on tty1 and read limits"
-              (wait-for-file "/etc/security/limits.conf" marionette))
+              '(("99")                  ;real-time priority
+                ("unlimited"))          ;max locked memory
 
-            (test-equal "/etc/security/limits.conf content matches"
+              (begin
-              #$(string-join (map pam-limits-entry->string pam-limit-entries)
+                ;; Wait for tty1.
-                             "\n" 'suffix)
+                (marionette-eval '(begin
-              (marionette-eval
+                                    (use-modules (gnu services herd))
-               '(begin
+                                    (start-service 'term-tty1))
-                  (use-modules (rnrs io ports))
+                                 marionette)
-                  (call-with-input-file "/etc/security/limits.conf"
+
-                    get-string-all))
+                (marionette-control "sendkey ctrl-alt-f1" marionette)
-               marionette))
+
+                ;; Now we can type.
+                (marionette-type "root\n" marionette)
+                (marionette-type "ulimit -r > real-time-priority\n" marionette)
+                (marionette-type "ulimit -l > max-locked-memory\n" marionette)
+
+                ;; Read the two files.
+                (marionette-eval '(use-modules (rnrs io ports)) marionette)
+                (let ((guest-file (lambda (file)
+                                    (string-tokenize
+                                     (wait-for-file file marionette
+                                                    #:read 'get-string-all)))))
+                  (list (guest-file "/root/real-time-priority")
+                        (guest-file "/root/max-locked-memory")))))
 
             (test-end)))))
 
@@ -83,17 +100,6 @@
 (define %test-pam-limits
   (system-test
    (name "pam-limits-service")
-   (description "Test that pam-limits-service can serialize its config
+   (description "Test that pam-limits-service actually sets the limits as
-(as a list) to @file{limits.conf}.")
+configured.")
    (value (run-test-pam-limits pam-limit-entries))))
-
-(define %test-pam-limits-deprecated
-  (system-test
-   (name "pam-limits-service-deprecated")
-   (description "Test that pam-limits-service can serialize its config
-(as a file-like object) to @file{limits.conf}.")
-   (value (run-test-pam-limits
-           (plain-file "limits.conf"
-                       (string-join (map pam-limits-entry->string
-                                         pam-limit-entries)
-                                    "\n" 'suffix))))))