;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2017 David Craven <david@craven.ch>
;;; Copyright © 2017, 2020, 2022 Mathieu Othacehe <othacehe@gnu.org>
;;; Copyright © 2017 Leo Famulari <leo@famulari.name>
;;; Copyright © 2019, 2021, 2023 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
;;; Copyright © 2022 Josselin Poiret <dev@jpoiret.xyz>
;;; Copyright © 2022 Reza Alizadeh Majd <r.majd@pantherx.org>
;;; Copyright © 2024 Tomas Volf <~@wolfsden.cz>
;;; Copyright © 2024 Lilah Tascheter <lilah@lunabee.space>
;;;
;;; 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 (gnu bootloader)
  #:autoload   (gnu build file-systems)
               (read-partition-label read-partition-uuid
                find-partition-by-label find-partition-by-uuid)
  #:use-module (gnu system file-systems)
  #:use-module (gnu system uuid)
  #:autoload   (guix build syscalls)
               (mounts mount-source mount-point mount-type)
  #:use-module (guix deprecation)
  #:use-module (guix diagnostics)
  #:use-module (guix gexp)
  #:use-module (guix i18n)
  #:use-module (guix modules)
  #:use-module (guix profiles)
  #:use-module (guix records)
  #:use-module (guix utils)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-26)
  #:use-module (srfi srfi-34)
  #:use-module (srfi srfi-35)
  #:use-module (ice-9 match)
  #:use-module (ice-9 receive)
  #:export (<menu-entry>
            menu-entry
            menu-entry?
            menu-entry-label
            menu-entry-device
            menu-entry-device-mount-point
            menu-entry-device-subvol
            menu-entry-linux
            menu-entry-linux-arguments
            menu-entry-initrd
            menu-entry-multiboot-kernel
            menu-entry-multiboot-arguments
            menu-entry-multiboot-modules
            menu-entry-chain-loader

            normalize-file
            menu-entry->sexp
            sexp->menu-entry

            bootloader
            bootloader?
            bootloader-name
            bootloader-default-targets
            bootloader-installer

            <bootloader-target>
            bootloader-target
            bootloader-target?
            bootloader-target-type
            bootloader-target-expected?
            bootloader-target-path
            bootloader-target-offset
            bootloader-target-device
            bootloader-target-file-system
            bootloader-target-label
            bootloader-target-uuid

            target-error?
            target-error-type
            target-error-targets

            gbegin
            :path :devpath :device :fs :label :uuid
            with-targets

            <bootloader-configuration>
            bootloader-configuration
            bootloader-configuration?
            bootloader-configuration-bootloader
            bootloader-configuration-targets
            bootloader-configuration-menu-entries
            bootloader-configuration-default-entry
            bootloader-configuration-efi-removable?
            bootloader-configuration-32bit?
            bootloader-configuration-keypair
            bootloader-configuration-timeout
            bootloader-configuration-keyboard-layout
            bootloader-configuration-theme
            bootloader-configuration-terminal-outputs
            bootloader-configuration-terminal-inputs
            bootloader-configuration-serial-unit
            bootloader-configuration-serial-speed
            bootloader-configuration-device-tree-support?
            bootloader-configuration-extra-initrd

            bootloader-configuration->gexp
            bootloader-configurations->gexp

            %efi-supported-systems
            efi-arch
            install-efi))

\f
;;;
;;; Menu-entry record.
;;;

(define-record-type* <menu-entry>
  menu-entry make-menu-entry
  menu-entry?
  (label           menu-entry-label)
  (device          menu-entry-device       ; file system uuid, label, or #f
                   (default #f))
  (device-mount-point menu-entry-device-mount-point
                   (default #f))
  (device-subvol menu-entry-device-subvol
                   (default #f))
  (linux           menu-entry-linux
                   (default #f))
  (linux-arguments menu-entry-linux-arguments
                   (default '()))          ; list of string-valued gexps
  (initrd          menu-entry-initrd       ; file name of the initrd as a gexp
                   (default #f))
  (multiboot-kernel menu-entry-multiboot-kernel
                    (default #f))
  (multiboot-arguments menu-entry-multiboot-arguments
                       (default '()))      ; list of string-valued gexps
  (multiboot-modules menu-entry-multiboot-modules
                     (default '()))        ; list of multiboot commands, where
                                           ; a command is a list of <string>
  (chain-loader     menu-entry-chain-loader
                    (default #f)))         ; string, path of efi file

(define (normalize-file entry val)
  "Normalize a file VAL stored in a menu entry into one suitable for a
bootloader.  Realizes device-mount-point and device-subvol."
  (match-record entry <menu-entry> (device-mount-point device-subvol)
    #~(let* ((rel (lambda (s) (substring s (if (string-prefix? "/" s) 1 0))))
             (file (rel #$val))
             (subvol (and=> #$device-subvol rel))
             (mount (and=> #$device-mount-point rel)))
        (string-append (if subvol (string-append "/" subvol "/") "/")
                       (if (and mount (string-prefix? mount file))
                           (substring file (string-length mount)) file)))))

(define (report-menu-entry-error menu-entry)
  (raise
   (condition
    (&message
     (message
      (format #f (G_ "invalid menu-entry: ~a") menu-entry)))
    (&fix-hint
     (hint
      (G_ "Please chose only one of:
@enumerate
@item direct boot by specifying fields @code{linux},
@code{linux-arguments} and @code{linux-modules},
@item multiboot by specifying fields @code{multiboot-kernel},
@code{multiboot-arguments} and @code{multiboot-modules},
@item chain-loader by specifying field @code{chain-loader}.
@end enumerate"))))))

(define (menu-entry->sexp entry)
  "Return ENTRY serialized as an sexp."
  (define (device->sexp device)
    (match device
      ((? uuid? uuid)
       `(uuid ,(uuid-type uuid) ,(uuid->string uuid)))
      ((? file-system-label? label)
       `(label ,(file-system-label->string label)))
      (_ device)))
  (match entry
    (($ <menu-entry> label device mount-point subvol
                     (? identity linux) linux-arguments (? identity initrd)
                     #f () () #f)
     `(menu-entry (version 0)
                  (label ,label)
                  (device ,(device->sexp device))
                  (device-mount-point ,mount-point)
                  (linux ,linux)
                  (linux-arguments ,linux-arguments)
                  (initrd ,initrd)
                  (device-subvol ,subvol)))
    (($ <menu-entry> label device mount-point subvol #f () #f
                     (? identity multiboot-kernel) multiboot-arguments
                     multiboot-modules #f)
     `(menu-entry (version 0)
                  (label ,label)
                  (device ,(device->sexp device))
                  (device-mount-point ,mount-point)
                  (multiboot-kernel ,multiboot-kernel)
                  (multiboot-arguments ,multiboot-arguments)
                  (multiboot-modules ,multiboot-modules)
                  (device-subvol ,subvol)))
    (($ <menu-entry> label device mount-point subvol #f () #f #f () ()
                     (? identity chain-loader))
     `(menu-entry (version 0)
                  (label ,label)
                  (device ,(device->sexp device))
                  (device-mount-point ,mount-point)
                  (chain-loader ,chain-loader)
                  (device-subvol ,subvol)))
    (_ (report-menu-entry-error entry))))

(define (sexp->menu-entry sexp)
  "Turn SEXP, an sexp as returned by 'menu-entry->sexp', into a <menu-entry>
record."
  ;; XXX: rely on shadowing to support the match ors below
  (define subvol #f)
  (define (sexp->device device-sexp)
    (match device-sexp
      (('uuid type uuid-string)
       (uuid uuid-string type))
      (('label label)
       (file-system-label label))
      (_ device-sexp)))
  (match sexp
    (('menu-entry ('version 0)
                  ('label label) ('device device)
                  ('device-mount-point mount-point)
                  ('linux linux) ('linux-arguments linux-arguments)
                  ('initrd initrd)
                  (or ('device-subvol subvol _ ...) (_ ...)))
     (menu-entry
      (label label)
      (device (sexp->device device))
      (device-mount-point mount-point)
      (device-subvol subvol)
      (linux linux)
      (linux-arguments linux-arguments)
      (initrd initrd)))
    (('menu-entry ('version 0)
                  ('label label) ('device device)
                  ('device-mount-point mount-point) ('device-subvol subvol)
                  ('multiboot-kernel multiboot-kernel)
                  ('multiboot-arguments multiboot-arguments)
                  ('multiboot-modules multiboot-modules)
                  (or ('device-subvol subvol _ ...) (_ ...)))
     (menu-entry
      (label label)
      (device (sexp->device device))
      (device-mount-point mount-point)
      (device-subvol subvol)
      (multiboot-kernel multiboot-kernel)
      (multiboot-arguments multiboot-arguments)
      (multiboot-modules multiboot-modules)))
    (('menu-entry ('version 0)
                  ('label label) ('device device)
                  ('device-mount-point mount-point) ('device-subvol subvol)
                  ('chain-loader chain-loader)
                  (or ('device-subvol subvol _ ...) (_ ...)))
     (menu-entry
      (label label)
      (device (sexp->device device))
      (device-mount-point mount-point)
      (device-subvol subvol)
      (chain-loader chain-loader)))))

\f
;;;
;;; Bootloader record.
;;;

;; The <bootloader> record contains fields expressing how the bootloader
;; should be installed. Every bootloader in gnu/bootloader/ directory
;; has to be described by this record.

(define-record-type* <bootloader>
  bootloader make-bootloader bootloader?
  (name            bootloader-name)
  (default-targets bootloader-default-targets (default '()))
  (installer       bootloader-installer))

\f
;;;
;;; Bootloader target record.
;;;

;; <bootloader-target> represents different kinds of targets in a normalized form.

(define-record-type* <bootloader-target>
  bootloader-target make-bootloader-target bootloader-target?
  (type bootloader-target-type)                            ; symbol
  (expected? bootloader-target-expected? (default #f))     ; bool

  (path bootloader-target-path (default #f))               ; string|#f
  (offset bootloader-target-offset (thunked)               ; symbol|#f
          (default (and (bootloader-target-path this-record)
                        (not (eq? (bootloader-target-type this-record) 'root))
                        'root)))
  (device bootloader-target-device (default #f))           ; string|#f
  (file-system bootloader-target-file-system (default #f)) ; string|#f
  (label bootloader-target-label (default #f))             ; string|#f
  (uuid bootloader-target-uuid (default #f)))              ; uuid|#f

(define-condition-type &target-error &error target-error?
  (type target-error-type)
  (targets target-error-targets))

(define (pathcat p1 p2)
  (string-append (string-trim-right p1 #\/) "/" (string-trim p2 #\/)))

(define* (get-target-of-type type targets #:optional (require? #f))
  "Finds a target in TARGETS of type TYPE, optionally providing an error when
not found if REQUIRE? is provided."
  (let* ((pred (lambda (target) (eq? type (bootloader-target-type target))))
         (candidates (filter pred targets))
         (ret (if (pair? candidates) (car candidates) #f)))
    (if (and require? (not ret))
      (raise (condition
               (&message (message (G_ "required, but not provided")))
               (&target-error (type type) (targets targets))))
      ret)))

(define (parent-of target targets)
  (and=> (bootloader-target-offset target)
         (cut get-target-of-type <> targets #t)))

(define (unfold-pathcat target targets)
  (let ((quit (lambda (t) (not (and=> t bootloader-target-path)))))
    (reduce pathcat #f
      (unfold quit bootloader-target-path (cut parent-of <> targets) target))))

(define (target-base? t)
  (or (not t) (match-record t <bootloader-target>
                (expected? offset device label uuid)
                (or device label uuid (not offset) expected?))))

(define (type-major? target) (memq target '(root esp disk)))

(define (ensure types targets end)
  (let* ((used-in (cute unfold end identity (cut parent-of <> targets) <>))
         (cons-in (lambda (t) (cons t (used-in t))))
         (ensure (map (cut get-target-of-type <> targets #t) types)))
    (filter ->bool (apply append (map cons-in ensure)))))

(define* (ensure-target-types types targets #:optional (base? #f))
  "Ensures all TYPES are provided in TARGETS.  Returns #t iff every ensured
target and its requirements are fully provided.  Errors out when a required TYPE
isn't provided.  When BASE?, only ensure path requirements up to a device."
  (not (any bootloader-target-expected?
         (ensure types targets (if base? target-base? not)))))

(define (ensure-majors types targets)
  "Errors out when a required TYPE isn't provided, or when use of multiple major
targets is detected."
  (let* ((all (map bootloader-target-type (ensure types targets target-base?)))
         (majors (delete-duplicates (filter type-major? all) eq?)))
    (if (< (length majors) 2) #t
      (raise (condition (&message (message (G_ "multiple major targets used")))
                        (&target-error (type majors) (targets targets)))))))



(define (gbegin . gex)
  "Sequence provided g-expressions."
  (case (length gex) ((0) #f) ((1) (car gex)) (else #~(begin #$@gex))))

;; syntax matching on free literals breaks easily, so bind them
(define-syntax-rule (define-literal id) (define-syntax id (syntax-rules ())))
(define-literal :path)
(define-literal :devpath)
(define-literal :device)
(define-literal :fs)
(define-literal :label)
(define-literal :uuid)

(define-syntax with-targets
  (cut syntax-case <> ()
    ((_ targets-expr block ...)
     (let* ((genvars (compose generate-temporaries iota))
            (targets (car (genvars 1)))

            (path? (cut syntax-case <> (:path) ((_ :path) #t) (_ #f)))
            (qualified? (cut syntax-case <> (=>)
                          ((_ => spec ...) (any path? #'(spec ...)))
                          (_ #f)))

            (resolve
              (lambda (in target base)
                (with-syntax ((target target) (base base) (targets targets))
                  (syntax-case in
                    (:path :devpath :device :fs :label :uuid)
                    ((name _) (not (identifier? #'name))
                     #`(_ (syntax-error "binds must be to identifiers" #,in)))
                    ((name :device) #'(name (bootloader-target-device base)))
                    ((name :label) #'(name (bootloader-target-label base)))
                    ((name :uuid) #'(name (bootloader-target-uuid base)))
                    ((name :fs) #'(name (bootloader-target-file-system base)))
                    ((name :path) #'(name (unfold-pathcat target targets)))
                    ((name :devpath)
                     #'(name (pathcat "/" (bootloader-target-path target))))
                    (_ #`(_ (syntax-error "invalid binding spec" #,in)))))))
            (binds
              (lambda (spec)
                (syntax-case spec (=>)
                  ((type => binds ...)
                   (with-syntax (((target base) (genvars 2)) (targets targets))
                     (append
                       #`((get (lambda (t) (get-target-of-type t targets #t)))
                          (target (get type))
                          (base (if (target-base? target) target
                                  (get (bootloader-target-offset target)))))
                       (map (cut resolve <> #'target #'base) #'(binds ...)))))
                  (_ #f))))

            (blocks
              (cut syntax-case <> ()
                ((spec ... expr)
                 (let* ((specs #'(spec ...))
                        (lets (apply append (filter-map binds specs)))
                        (type (cut syntax-case <> (=>)
                                ((t => _ ...) #'t) (t #'t))))
                   (receive (full part) (partition qualified? specs)
                     #`(and (ensure-majors (list #,@(map type specs)) #,targets)
                            (ensure-target-types (list #,@(map type part))
                                                 #,targets #t)
                            (ensure-target-types (list #,@(map type full))
                                                 #,targets #f)
                            (let* #,lets expr)))))
                (bad #'(syntax-error "malformed block" bad)))))
       "Using the list TARGETS, evaluate and sequence each BLOCK to produce a
gexp. BLOCK is a set of SPECs followed by an EXPR (evaluating to a gexp). Each
SPEC denotes a type of target to guard EXPR on their existance and
full-qualification. This procedure is linear in regards to BLOCKs.

SPEC may be of the following forms:
@itemize
@item 'TYPE Requires TYPE to be fully present or promised. Errors otherwise.
@item ('TYPE => (VAR COMPONENT) ...): As type, but also binds variables. TYPE's
      COMPONENT is bound to the variable VAR as described below.
@end itemize

Available COMPONENTs are:
@itemize
@item :path (fully-qualified)
@item :devpath (relative from device)
@item :device (auto-detected from uuid and label if not user-provided)
@item :fs
@item :label
@item :uuid
@end itemize

Note that installers may be called multiple times with different targets being
fully-qualified.  To ensure that targets aren't installed multiple times, make sure
that each BLOCK ensures at least one major target, either directly or indirectly.
Corrolarily, at most one major target should be ensured per BLOCK, under the same
conditions. Major targets originate from disk image handling, and are currently:
@itemize
@item disk
@item root
@item esp
@end itemize"
       #`(let ((#,targets targets-expr))
           (apply gbegin (filter ->bool
                           (list #,@(map blocks #'(block ...))))))))
    (bad #'(syntax-error "must provide targets" bad))))

\f
;;;
;;; Bootloader configuration record.
;;;

;; The <bootloader-configuration> record contains bootloader independant
;; configuration used to fill bootloader configuration file.

(define-with-syntax-properties (warn-update-targets (value properties))
  (let ((loc (source-properties->location properties)))
    (define update
      (match-lambda
        ((? bootloader-target? target) (cons #f target))
        ((? string? s) (cons #t (if (string-prefix? "/dev" s)
                                  (bootloader-target
                                    (type 'disk)
                                    (device s))
                                  (bootloader-target
                                    (type 'esp)
                                    (offset 'root)
                                    (path s)))))
        (x (error loc (G_ "invalid target '~a'~%") x))))

    (let* ((updated (map update (if (list? value) value (list value))))
           (targets (map cdr updated))
           (types (map bootloader-target-type targets)))
      ;; XXX: should this be an error?
      (when (any car updated)
        (warning loc (G_ "the 'targets' field should now contain \
<bootloader-target> records. inferring a best guess (this might break!)...~%")))
      (when (not (eqv? (length types) (length (delete-duplicates types))))
        (error loc (G_ "the 'targets' field may not contain duplicates~%")))
      targets)))

(define-record-type* <bootloader-configuration>
  bootloader-configuration make-bootloader-configuration
  bootloader-configuration?
  (bootloader
   bootloader-configuration-bootloader)   ;<bootloader>
  (targets               bootloader-configuration-targets
                         (default '())    ;list of strings
                         (sanitize warn-update-targets))
  (menu-entries          bootloader-configuration-menu-entries
                         (default '()))   ;list of <menu-entry>
  (default-entry         bootloader-configuration-default-entry
                         (default 0))     ;integer
  (efi-removable?        bootloader-configuration-efi-removable?
                         (default #f))    ;bool
  (32bit?                bootloader-configuration-32bit?
                         (default #f))    ;bool
  (keypair               bootloader-configuration-keypair
                         (default #f))    ;(cert . priv) pair
  (timeout               bootloader-configuration-timeout
                         (default 5))     ;seconds as integer
  (keyboard-layout       bootloader-configuration-keyboard-layout
                         (default #f))    ;<keyboard-layout> | #f
  (theme                 bootloader-configuration-theme
                         (default #f))    ;bootloader-specific theme
  (terminal-outputs      bootloader-configuration-terminal-outputs
                         (default #f))    ;list of symbols | #f (default outs)
  (terminal-inputs       bootloader-configuration-terminal-inputs
                         (default #f))    ;list of symbols | #f (default ins)
  (serial-unit           bootloader-configuration-serial-unit
                         (default #f))    ;integer | #f
  (serial-speed          bootloader-configuration-serial-speed
                         (default #f))    ;integer | #f
  (device-tree-support?  bootloader-configuration-device-tree-support?
                         (default #t))    ;boolean
  (extra-initrd          bootloader-configuration-extra-initrd
                         (default #f)))   ;string | #f

\f
;;;
;;; Bootloader installation paths.
;;;

;; highest -> lowest priority
(define (target-overrides . layers)
  (let* ((types (fold append '()
                  (map (cute map bootloader-target-type <>) layers)))
         (pred (lambda (type layer found)
                 (or found (get-target-of-type type layer))))
         (find (lambda (type) (fold (cute pred type <> <>) #f layers))))
    (filter ->bool (map find (delete-duplicates types)))))

(define (normalize targets)
  "Augments user-supplied targets with filesystem information at runtime,
allowing users to specify a lot less information.  Relatively minimal to prevent
errors.  Puts targets into a normal form, where all paths are fully specified up
to a device offset."
  (let* ((mass (lambda (m) `((,(mount-source m) . ,m) (,(mount-point m) . ,m))))
         (amounts (delay (apply append (map mass (mounts)))))
         (accessible=> (lambda (d f) (and d (access? d R_OK) (f d))))
         (assoc-mnt (lambda (f) (lambda (v)
                                  (and=> (assoc-ref (force amounts) v) f)))))

    (define (scrape target)
      (match-record target <bootloader-target>
        (expected? path offset device label uuid file-system)
        (if expected? target
          (bootloader-target
            (inherit target)
            (device (or device (false-if-exception
                                 (or (and=> uuid find-partition-by-uuid)
                                     (and=> label find-partition-by-label)))
                               (and path ((assoc-mnt mount-source)
                                          (unfold-pathcat target targets)))))
            (label (or label (accessible=> device read-partition-label)))
            (uuid (or uuid (accessible=> device read-partition-uuid)))
            (file-system (or file-system (and=> device (assoc-mnt mount-type))))
            (offset (and path offset))
            (path (or path (and=> device (assoc-mnt mount-point))))))))

    (define (arborify target targets)
      (let* ((up (lambda (t) (and t (parent-of t targets))))
             (proto (unfold target-base? identity up (up target) list))
             (chain (reverse (cons target proto))))
        (bootloader-target
          (inherit target)
          (offset (and=> (car chain) bootloader-target-type))
          (path (reduce pathcat #f (map bootloader-target-path (cdr chain)))))))

    (let ((mid (map scrape targets))) (map (cut arborify <> mid) mid))))

(define* (bootloader-configuration->gexp bootloader-config args #:key
                                          (root-offset "/") (overrides '()))
  "Returns a gexp to install BOOTLOADER-CONFIG to its targets, passing ARGS
to each installer alongside the additional #:bootloader-config keyword
arguments.  Target OVERRIDES are applied and all path targets have ROOT-OFFSET
applied.  The following keyword arguments are expected in ARGS:
@enumerate
@item current-boot-alternative
@item old-boot-alternatives
@item locale (from bootmeta)
@item store-directory-prefix (from bootmeta)
@item store-crypto-devices (from bootmeta)
@end enumerate"
  (let* ((bootloader (bootloader-configuration-bootloader bootloader-config))
         (installer (bootloader-installer bootloader))
         (auto-targets (list (bootloader-target
                               (type 'root)
                               (path root-offset)
                               (offset #f))))
         (targets (target-overrides
                    overrides
                    (bootloader-configuration-targets bootloader-config)
                    auto-targets
                    (bootloader-default-targets bootloader)))
         (conf (bootloader-configuration
                 (inherit bootloader-config)
                 (targets (normalize targets)))))
    (apply installer #:bootloader-config conf args)))

(define (bootloader-configurations->gexp bootloader-configs . rest)
  (apply gbegin (filter-map (cut apply bootloader-configuration->gexp <> rest)
                            bootloader-configs)))

\f
;;;
;;; EFI shit
;;;

;; systems currently supported by efi-arch. should be used for packages relying
;; on it.
(define %efi-supported-systems
  '("i686-linux" "x86_64-linux" "armhf-linux" "aarch64-linux" "riscv64-linux"))

(define* (efi-arch #:key (target (or (%current-target-system) (%current-system)))
                         (32? #f))
  "Returns the UEFI architecture name for the current target, in lowercase."
  (cond ((target-x86-32? target)  "ia32")
        ((target-x86-64? target)  (if 32? "ia32" "x64"))
        ((target-arm32? target)   "arm")
        ((target-aarch64? target) (if 32? "arm" "aa64"))
        ((target-riscv64? target) (if 32? "riscv32" "riscv64"))
        (else (raise (formatted-message (G_ "no UEFI standard arch for ~a!")
                                        target)))))

(define (lazy-efibootmgr)
  "Lazy-loaded efibootmgr package, in order to prevent circular refs."
  (module-ref (resolve-interface '(gnu packages linux)) 'efibootmgr))

(define (install-efi bootloader-config plan)
  "Returns a gexp installing PLAN to the ESP, as denoted by the 'vendir target.
PLAN is a gexp of a list of '(BUILDER DEST-BASENAME . LABEL) triples, that
should be in boot order.  If the user selects a removable bootloader, only the
first entry in PLAN is used."
  (match-record bootloader-config <bootloader-configuration>
    (targets efi-removable? 32bit?)
    (if efi-removable?
      ;; Hard code the output location to a well-known path recognized by
      ;; compliant firmware. See "3.5.1.1 Removable Media Boot Behaviour":
      ;; http://www.uefi.org/sites/default/files/resources/UEFI%20Spec%202_6.pdf
      (with-targets targets
        (('esp => (path :path))
         #~(let ((boot #$(string-append path "/EFI/BOOT"))
                 (arch #$(string-upcase (efi-arch #:32? 32bit?)))
                 (builder (car (car #$plan))))
             (mkdir-p boot)
             ;; only realize first planspec
             (builder (string-append boot "/BOOT" arch ".EFI")))))
      ;; normal install when not doing a removable config
      (with-targets targets
        (('vendir => (vendir :path) (loader :devpath) (disk :device))
         #~(install-efi #+(file-append (lazy-efibootmgr) "/sbin/efibootmgr")
                        #$vendir #$loader #$disk #$plan))))))