Re: 18/36: services: hurd: Add dummy loopback.

[Jan Nieuwenhuizen <janneke@gnu.org>]

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Ludovic Courtès writes:

Hi,

>> Something like that: sizeof-ifconf is set to 16 (like on x86_64), but
>> it's size should be 8.
>
> Oh, that’s because ‘define-c-struct’ does all the work at
> macro-expansion time, with the host types and alignment constraints.  I
> wonder how we didn’t notice it earlier.  Cross-compiling from x86_64 to
> ARMv7 has the same problem, but maybe the networking ioctls work by
> chance.
>
> The patch below appears to fix it:

Yes, it fixes the struct sizes in the cross-compiled .go file.  Thanks!
I have added it as the attached patch to "wip-hurd-vm" for now.  I did

    ./pre-inst-env guild compile --target=i586-pc-gnu -o syscalls.go guix/build/syscalls.scm 

and copied that to the Hurd.

When running this (changed #$... to UPPERCASE)

--8<---------------cut here---------------start------------->8---
(use-modules (guix build syscalls))

(define LOOPBACK? #t)
(define IP "127.0.0.1" )
(define INTERFACE "lo")
(define NETMASK #f)
(define GATEWAY #f)

(format #t "ifreq-struct-size: ~a\n" (@@ (guix build syscalls) ifreq-struct-size))
(format #t "sizeof-ifconf: ~s\n" (@@ (guix build syscalls) sizeof-ifconf))
(define (test)
  (let* ((addr     (inet-pton AF_INET IP))
         (sockaddr (make-socket-address AF_INET addr 0))
         (mask     (and NETMASK
                        (inet-pton AF_INET NETMASK)))
         (maskaddr (and mask
                        (make-socket-address AF_INET
                                             mask 0)))
         (gateway  (and GATEWAY
                        (inet-pton AF_INET GATEWAY)))
         (gatewayaddr (and gateway
                           (make-socket-address AF_INET
                                                gateway 0))))
    (configure-network-interface INTERFACE sockaddr
                                 (logior IFF_UP
                                         (if LOOPBACK?
                                             IFF_LOOPBACK
                                             0))
                                 #:netmask maskaddr)
    (when gateway
      (let ((sock (socket AF_INET SOCK_DGRAM 0)))
        (add-network-route/gateway sock gatewayaddr)
        (close-port sock)))))

(test)
--8<---------------cut here---------------end--------------->8---

Now I see the correct sizes...

root@guixygnu# guile -L . -C . static.scm 
;;; note: source file /root/static.scm
;;;       newer than compiled /root/.cache/guile/ccache/3.0-LE-4-4.2/root/static.scm.go
;;; note: auto-compilation is enabled, set GUILE_AUTO_COMPILE=0
;;;       or pass the --no-auto-compile argument to disable.
;;; compiling /root/static.scm
;;; compiled /root/.cache/guile/ccache/3.0-LE-4-4.2/root/static.scm.go
ifreq-struct-size: 32
sizeof-ifconf: 8
Backtrace:
In ice-9/boot-9.scm:
  1736:10  9 (with-exception-handler _ _ #:unwind? _ # _)
In unknown file:
           8 (apply-smob/0 #<thunk 2e6430>)
In ice-9/boot-9.scm:
    718:2  7 (call-with-prompt _ _ #<procedure default-prompt-handle?>)
In ice-9/eval.scm:
    619:8  6 (_ #(#(#<directory (guile-user) 2dd820>)))
In ice-9/boot-9.scm:
   2806:4  5 (save-module-excursion _)
  4351:12  4 (_)
In static.scm:
     24:4  3 (test)
In guix/build/syscalls.scm:
   1529:8  2 (configure-network-interface "lo" #(2 2130706433 0) 9 # _)
  1464:18  1 (_ _ "lo" _)
In unknown file:
Exception thrown while printing backtrace:
In procedure primitive-call-ip: Wrong type argument in position 1 (expecting PRIMITIVE_P): #<procedure 8f8560 (_ _ _)>

ERROR: Value out of range 0 to 4294967295: -1

...but still/again a similar range error; Ideas?

Greetings,
janneke


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From 33fbfcd7f46cf675cc24db92b1110d38afa51ae5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ludovic=20Court=C3=A8s?= <ludo@gnu.org>
Date: Tue, 5 May 2020 11:53:39 +0200
Subject: [PATCH] syscalls: Cross-build fix for alignof*, sizeof*.

See <https://lists.gnu.org/archive/html/guix-devel/2020-05/msg00008.html>.
Reported by Jan (janneke) Nieuwenhuizen <janneke@gnu.org>.

* guix/build/syscalls.scm (sizeof*, alignof*): When cross-compiling, emit code
to call at runtime.
---
 guix/build/syscalls.scm | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/guix/build/syscalls.scm b/guix/build/syscalls.scm
index 73b439fb7d..00d8ceb480 100644
--- a/guix/build/syscalls.scm
+++ b/guix/build/syscalls.scm
@@ -23,6 +23,7 @@
 
 (define-module (guix build syscalls)
   #:use-module (system foreign)
+  #:use-module (system base target)
   #:use-module (rnrs bytevectors)
   #:autoload   (ice-9 binary-ports) (get-bytevector-n)
   #:use-module (srfi srfi-1)
@@ -194,9 +195,14 @@
      (* (sizeof* type) n))
     ((_ type)
      (let-syntax ((v (lambda (s)
-                       (let ((val (sizeof type)))
-                         (syntax-case s ()
-                           (_ val))))))
+                       ;; When compiling natively, call 'sizeof' at expansion
+                       ;; time; otherwise, emit code to call it at run time.
+                       (syntax-case s ()
+                         (_
+                          (if (= (target-word-size)
+                                 (with-target %host-type target-word-size))
+                              (sizeof type)
+                              #'(sizeof type)))))))
        v))))
 
 (define-syntax alignof*
@@ -208,9 +214,14 @@
      (alignof* type))
     ((_ type)
      (let-syntax ((v (lambda (s)
-                       (let ((val (alignof type)))
-                         (syntax-case s ()
-                           (_ val))))))
+                       ;; When compiling natively, call 'sizeof' at expansion
+                       ;; time; otherwise, emit code to call it at run time.
+                       (syntax-case s ()
+                         (_
+                          (if (= (target-word-size)
+                                 (with-target %host-type target-word-size))
+                              (alignof type)
+                              #'(alignof type)))))))
        v))))
 
 (define-syntax align                             ;as found in (system foreign)
-- 
2.26.0


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