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-rw-r--r--guix/build/syscalls.scm51
1 files changed, 49 insertions, 2 deletions
diff --git a/guix/build/syscalls.scm b/guix/build/syscalls.scm
index 4bcb2a871c..0de39aee6b 100644
--- a/guix/build/syscalls.scm
+++ b/guix/build/syscalls.scm
@@ -2,6 +2,7 @@
;;; Copyright © 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2015 David Thompson <davet@gnu.org>
;;; Copyright © 2015 Mark H Weaver <mhw@netris.org>
+;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
;;;
;;; This file is part of GNU Guix.
;;;
@@ -149,8 +150,19 @@
;;; Commentary:
;;;
;;; This module provides bindings to libc's syscall wrappers. It uses the
-;;; FFI, and thus requires a dynamically-linked Guile. (For statically-linked
-;;; Guile, we instead apply 'guile-linux-syscalls.patch'.)
+;;; FFI, and thus requires a dynamically-linked Guile.
+;;;
+;;; Some syscalls are already defined in statically-linked Guile by applying
+;;; 'guile-linux-syscalls.patch'.
+;;;
+;;; Visibility of syscall's symbols shared between this module and static Guile
+;;; is a bit delicate. It is handled by 'define-as-needed' macro.
+;;;
+;;; This macro is used to export symbols in dynamic Guile context, and to
+;;; re-export them in static Guile context.
+;;;
+;;; This way, even if they don't appear in #:export list, it is safe to use
+;;; syscalls from this module in static or dynamic Guile context.
;;;
;;; Code:
@@ -409,6 +421,25 @@ the returned procedure is called."
(error (format #f "~a: syscall->procedure failed: ~s"
name args))))))
+(define-syntax define-as-needed
+ (syntax-rules ()
+ "Define VARIABLE. If VARIABLE already exists in (guile) then re-export it,
+ otherwise export the newly-defined VARIABLE."
+ ((_ (proc args ...) body ...)
+ (define-as-needed proc (lambda* (args ...) body ...)))
+ ((_ variable value)
+ (begin
+ (when (module-defined? the-scm-module 'variable)
+ (re-export variable))
+
+ (define variable
+ (if (module-defined? the-scm-module 'variable)
+ (module-ref the-scm-module 'variable)
+ value))
+
+ (unless (module-defined? the-scm-module 'variable)
+ (export variable))))))
+
;;;
;;; File systems.
@@ -547,6 +578,22 @@ constants from <sys/mount.h>."
(list device (strerror err))
(list err)))))))
+(define-as-needed RB_AUTOBOOT #x01234567)
+(define-as-needed RB_HALT_SYSTEM #xcdef0123)
+(define-as-needed RB_ENABLED_CAD #x89abcdef)
+(define-as-needed RB_DISABLE_CAD 0)
+(define-as-needed RB_POWER_OFF #x4321fedc)
+(define-as-needed RB_SW_SUSPEND #xd000fce2)
+(define-as-needed RB_KEXEC #x45584543)
+
+(define-as-needed (reboot #:optional (cmd RB_AUTOBOOT))
+ (let ((proc (syscall->procedure int "reboot" (list int))))
+ (let-values (((ret err) (proc cmd)))
+ (unless (zero? ret)
+ (throw 'system-error "reboot" "~S: ~A"
+ (list cmd (strerror err))
+ (list err))))))
+
(define (kernel? pid)
"Return #t if PID designates a \"kernel thread\" rather than a normal
user-land process."