2 files changed, 64 insertions, 1 deletions
diff --git a/gnu/system/pam.scm b/gnu/system/pam.scm
index eedf933946..13f76a50ed 100644
--- a/gnu/system/pam.scm
+++ b/gnu/system/pam.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2013, 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2013, 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -50,6 +50,9 @@
             unix-pam-service
             base-pam-services
 
+            session-environment-service
+            session-environment-service-type
+
             pam-root-service-type
             pam-root-service))
 
@@ -278,6 +281,48 @@ authenticate to run COMMAND."
 
 
 ;;;
+;;; System-wide environment variables.
+;;;
+
+(define (environment-variables->environment-file vars)
+  "Return a file for pam_env(8) that contains environment variables VARS."
+  (apply mixed-text-file "environment"
+         (append-map (match-lambda
+                       ((key . value)
+                        (list key "=" value "\n")))
+                     vars)))
+
+(define session-environment-service-type
+  (service-type
+   (name 'session-environment)
+   (extensions
+    (list (service-extension
+           etc-service-type
+           (lambda (vars)
+             (list `("environment"
+                     ,(environment-variables->environment-file vars)))))))
+   (compose concatenate)
+   (extend append)
+   (description
+    "Populate @file{/etc/environment}, which is honored by @code{pam_env},
+with the specified environment variables.  The value of this service is a list
+of name/value pairs for environments variables, such as:
+
+@example
+'((\"TZ\" . \"Canada/Pacific\"))
+@end example\n")))
+
+(define (session-environment-service vars)
+  "Return a service that builds the @file{/etc/environment}, which can be read
+by PAM-aware applications to set environment variables for sessions.
+
+VARS should be an association list in which both the keys and the values are
+strings or string-valued gexps."
+  (service session-environment-service-type vars))
+
+
+
+;;;
 ;;; PAM root service.
 ;;;
 
diff --git a/gnu/system/uuid.scm b/gnu/system/uuid.scm
index 1dd6a11339..6470abb8cc 100644
--- a/gnu/system/uuid.scm
+++ b/gnu/system/uuid.scm
@@ -41,6 +41,7 @@
             string->ext3-uuid
             string->ext4-uuid
             string->btrfs-uuid
+            string->fat32-uuid
             iso9660-uuid->string
 
             ;; XXX: For lack of a better place.
@@ -175,6 +176,22 @@ ISO9660 UUID representation."
         (low (bytevector-uint-ref uuid 2 %fat32-endianness 2)))
     (format #f "~:@(~x-~x~)" low high)))
 
+(define %fat32-uuid-rx
+  (make-regexp "^([[:xdigit:]]{4})-([[:xdigit:]]{4})$"))
+
+(define (string->fat32-uuid str)
+  "Parse STR, which is in FAT32 format, and return a bytevector or #f."
+  (match (regexp-exec %fat32-uuid-rx str)
+    (#f
+     #f)
+    (rx-match
+     (uint-list->bytevector (list (string->number
+                                   (match:substring rx-match 2) 16)
+                                  (string->number
+                                   (match:substring rx-match 1) 16))
+                            %fat32-endianness
+                            2))))
+
 
 ;;;
 ;;; Generic interface.
@@ -198,6 +215,7 @@ ISO9660 UUID representation."
 (define %uuid-parsers
   (vhashq
    ('dce 'ext2 'ext3 'ext4 'btrfs 'luks => string->dce-uuid)
+   ('fat32 'fat => string->fat32-uuid)
    ('iso9660 => string->iso9660-uuid)))
 
 (define %uuid-printers