1 files changed, 139 insertions, 0 deletions
diff --git a/guix/platform.scm b/guix/platform.scm
new file mode 100644
index 0000000000..361241cb2e
--- /dev/null
+++ b/guix/platform.scm
@@ -0,0 +1,139 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2021 Mathieu Othacehe <othacehe@gnu.org>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (guix platform)
+  #:use-module (guix discovery)
+  #:use-module (guix memoization)
+  #:use-module (guix records)
+  #:use-module (guix ui)
+  #:use-module (srfi srfi-1)
+  #:export (platform
+            platform?
+            platform-target
+            platform-system
+            platform-linux-architecture
+            platform-glibc-dynamic-linker
+
+            platform-modules
+            platforms
+            lookup-platform-by-system
+            lookup-platform-by-target
+            lookup-platform-by-target-or-system
+            platform-system->target
+            platform-target->system
+
+            systems
+            targets))
+
+
+;;;
+;;; Platform record.
+;;;
+
+;; Description of a platform supported by GNU Guix.
+;;
+;; The 'target' field must be a valid GNU triplet as defined here:
+;; https://www.gnu.org/software/autoconf/manual/autoconf-2.68/html_node/Specifying-Target-Triplets.html.
+;; It is used for cross-compilation purposes.
+;;
+;; The 'system' field is the name of the corresponding system as defined in
+;; the (gnu packages bootstrap) module.  It can be for instance
+;; "aarch64-linux" or "armhf-linux".  It is used to emulate a different host
+;; architecture, for instance i686-linux on x86_64-linux-gnu, or armhf-linux
+;; on x86_64-linux, using the QEMU binfmt transparent emulation mechanism.
+;;
+;; The 'linux-architecture' is only relevant if the kernel is Linux.  In that
+;; case, it corresponds to the ARCH variable used when building Linux.
+;;
+;; The 'glibc-dynamic-linker' field is the name of Glibc's dynamic linker for
+;; the corresponding system.
+(define-record-type* <platform> platform make-platform
+  platform?
+  (target               platform-target)
+  (system               platform-system)
+  (linux-architecture   platform-linux-architecture
+                        (default #f))
+  (glibc-dynamic-linker platform-glibc-dynamic-linker))
+
+
+;;;
+;;; Platforms.
+;;;
+
+(define (platform-modules)
+  "Return the list of platform modules."
+  (all-modules (map (lambda (entry)
+                      `(,entry . "guix/platforms"))
+                    %load-path)
+               #:warn warn-about-load-error))
+
+(define platforms
+  ;; The list of publically-known platforms.
+  (memoize
+   (lambda ()
+     (fold-module-public-variables (lambda (obj result)
+                                     (if (platform? obj)
+                                         (cons obj result)
+                                         result))
+                                   '()
+                                   (platform-modules)))))
+
+(define (lookup-platform-by-system system)
+  "Return the platform corresponding to the given SYSTEM."
+  (find (lambda (platform)
+          (let ((s (platform-system platform)))
+            (and (string? s) (string=? s system))))
+        (platforms)))
+
+(define (lookup-platform-by-target target)
+  "Return the platform corresponding to the given TARGET."
+  (find (lambda (platform)
+          (let ((t (platform-target platform)))
+            (and (string? t) (string=? t target))))
+        (platforms)))
+
+(define (lookup-platform-by-target-or-system target-or-system)
+  "Return the platform corresponding to the given TARGET or SYSTEM."
+  (or (lookup-platform-by-target target-or-system)
+      (lookup-platform-by-system target-or-system)))
+
+(define (platform-system->target system)
+  "Return the target matching the given SYSTEM if it exists or false
+otherwise."
+  (let ((platform (lookup-platform-by-system system)))
+    (and=> platform platform-target)))
+
+(define (platform-target->system target)
+  "Return the system matching the given TARGET if it exists or false
+otherwise."
+  (let ((platform (lookup-platform-by-target system)))
+    (and=> platform platform-system)))
+
+
+;;;
+;;; Systems & Targets.
+;;;
+
+(define (systems)
+  "Return the list of supported systems."
+  (delete-duplicates
+   (filter-map platform-system (platforms))))
+
+(define (targets)
+  "Return the list of supported targets."
+  (map platform-target (platforms)))