installer: Add core dump support.

Fixes: <https://issues.guix.gnu.org/58733>

* gnu/installer.scm (installer-program): Enable core dump generation.
* gnu/installer/dump.scm (%core-dump): New variable.
(prepare-dump): Copy the core dump file.
* gnu/installer/newt/welcome.scm (run-welcome-page): Propose to report an
installation that previously generated a core dump.

gnu/installer.scm

@@ -389,6 +389,12 @@ selected keymap."
                          (ice-9 match)
                          (ice-9 textual-ports))
 
+            ;; Enable core dump generation.
+            (setrlimit 'core #f #f)
+            (call-with-output-file "/proc/sys/kernel/core_pattern"
+              (lambda (port)
+                (format port %core-dump)))
+
             ;; Initialize gettext support so that installers can use
             ;; (guix i18n) module.
             #$init-gettext

gnu/installer/dump.scm

@@ -28,13 +28,17 @@
   #:use-module (web http)
   #:use-module (web response)
   #:use-module (webutils multipart)
-  #:export (prepare-dump
+  #:export (%core-dump
+            prepare-dump
             make-dump
             send-dump-report))
 
 ;; The installer crash dump type.
 (define %dump-type "installer-dump")
 
+;; The core dump file.
+(define %core-dump "/tmp/installer-core-dump")
+
 (define (result->list result)
   "Return the alist for the given RESULT."
   (hash-map->list (lambda (k v)
@@ -66,6 +70,10 @@ RESULT is the installer result hash table.  Returns the created directory path."
     ;; syslog
     (copy-file "/var/log/messages" "syslog")
 
+    ;; core dump
+    (when (file-exists? %core-dump)
+      (copy-file %core-dump "core-dump"))
+
     ;; dmesg
     (let ((pipe (open-pipe* OPEN_READ "dmesg")))
       (call-with-output-file "dmesg"

gnu/installer/newt/welcome.scm

@@ -20,6 +20,7 @@
 (define-module (gnu installer newt welcome)
   #:use-module ((gnu build linux-modules)
                 #:select (modules-loaded))
+  #:use-module (gnu installer dump)
   #:use-module (gnu installer steps)
   #:use-module (gnu installer utils)
   #:use-module (gnu installer newt page)
@@ -132,6 +133,20 @@ work well with only free software.  Expect trouble.  If after installation,
 the system does not boot, perhaps you will need to add nomodeset to the
 kernel arguments and need to configure the uvesafb kernel module.")
                       (G_ "Pre-install warning")))
+    (when (file-exists? %core-dump)
+      (match
+          (choice-window
+           (G_ "Previous installation failed")
+           (G_ "Continue")
+           (G_ "Report the failure")
+           (G_ "It seems that the previous installation exited unexpectedly \
+and generated a core dump.  Do you want to continue or to report the failure \
+first?"))
+        (1 #t)
+        (2 (raise
+            (condition
+             (&message
+              (message "User abort.")))))))
     (run-menu-page
      (G_ "GNU Guix install")
      (G_ "Welcome to GNU Guix system installer!