create a symlink

create a symlink

[Rene]

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Hello,

In 'gnu/build/install.scm', I try to create a symlink from '/gnu/store/..hurd-0.9' to /hurd during 'guix system init  '.

But Guix waits for a string, is it possible to use a package to do the symlink?

--------CODE---------------

(let ((hurd-1 (string-append target

                                     "/hurd")))

    (let try ()

      (catch 'system-error

             (lambda ()

               (symlink hurd hurd-1))

             (lambda args

               ;; If hurd-1 already exists, overwrite it.

               (if (= EEXIST (system-error-errno args))

                   (begin

                     (delete-file hurd-1)

                     (try))

                   (apply throw args))))))

-----------------------

-----------ERROR-------------

In guix/scripts/system.scm:

181: 4 [#<procedure b1fd9c0 at guix/scripts/system.scm:183:4 (state)> #]

In ice-9/eval.scm:

432: 3 [eval # #]

In ice-9/boot-9.scm:

157: 2 [catch system-error #<procedure afcd888 at ice-9/eval.scm:416:20 ()> ...]

157: 1 [catch system-error #<procedure afcd858 at guix/ui.scm:359:2 ()> ...]

In unknown file:

   ?: 0 [symlink # "/home/jin/subhurd/rfs/hurd"]

ERROR: In procedure symlink:

ERROR: Wrong type (expecting string): #<package hurd@0.9 gnu/packages/hurd.scm:251 98c7120>

--------------------------

Thank you

Rene

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Re: create a symlink

[Danny Milosavljevic]

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Hi Rene,

> But Guix waits for a string, is it possible to use a package to do the symlink?

Not directly - but you can "convert" a package to a string by putting in guix/scripts/system.scm :

  (install-hurd #$hurd)

or so (where "install-hurd" is your procedure in gnu/build/install.scm).

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Re: create a symlink

[Joshua Branson]

I guess I'm a little behind.  What's this install-hurd procedure?  Is
this getting the hurd running in a vm on a guixSD system?

Danny Milosavljevic <dannym@scratchpost.org> writes:

> Hi Rene,
>
>> But Guix waits for a string, is it possible to use a package to do the symlink?
>
> Not directly - but you can "convert" a package to a string by putting in guix/scripts/system.scm :
>
>   (install-hurd #$hurd)
>
> or so (where "install-hurd" is your procedure in gnu/build/install.scm).

Re: create a symlink

[Rene]

Hi Joshua,

On top of Debian/Hurd, We are trying to populate a partition with the binaries required to boot GNU Mach and GNU Hurd, through Guix with:

'guix system init'

You can see more on guix-devel mailing list and here:

https://github.com/Phant0mas/Guix-on-Hurd
https://github.com/methalo/guix.git

Re: create a symlink

[Rene]

Hello Danny,

after adding the line (install-hurd #$hurd), I have an error, I'm missing some module?


---------
1238: 15 [run-guix-command system "init" ...]
In ice-9/boot-9.scm:
 157: 14 [catch srfi-34 #<procedure 9c07b10 at guix/ui.scm:433:2 ()> ...]
 157: 13 [catch system-error #<procedure 9d05000 at ice-9/eval.scm:416:20 ()> ...]
In ice-9/eval.scm:
 481: 12 [lp (#<fluid 32>) (#t)]
In ice-9/r4rs.scm:
  90: 11 [dynamic-wind #<procedure 9ce9800 at ice-9/boot-9.scm:1133:2 _> ...]
In guix/store.scm:
1250: 10 [run-with-store # #<procedure 9d50ac8 at ice-9/eval.scm:416:20 (a)> # ...]
In ice-9/eval.scm:
 386: 9 [eval #<memoized ((<3> <1>) <0>)> (# #t # ...)]
 387: 8 [eval # #]
 387: 7 [eval # #]
 432: 6 [eval # #]
In ice-9/boot-9.scm:
 157: 5 [catch system-error #<procedure af39c78 at ice-9/eval.scm:416:20 ()> ...]
In ice-9/eval.scm:
 387: 4 [eval # #]
 387: 3 [eval # #]
 386: 2 [eval # #]
 393: 1 [eval # #]
In unknown file:
   ?: 0 [memoize-variable-access! #<memoized ungexp> #<directory # 89b0c60>]

ERROR: In procedure memoize-variable-access!:
ERROR: Unbound variable: ungexp
---------




‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On April 19, 2018 1:26 AM, Danny Milosavljevic <dannym@scratchpost.org> wrote:

> Hi Rene,
> 
> > But Guix waits for a string, is it possible to use a package to do the symlink?
> 
> Not directly - but you can "convert" a package to a string by putting in guix/scripts/system.scm :
> 
> (install-hurd #$hurd)
> 
> or so (where "install-hurd" is your procedure in gnu/build/install.scm).

Re: create a symlink

[Danny Milosavljevic]

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Hi Rene,

are you sure you put the call into guix/scripts/system.scm ?

There are a lot of #$ things there already - should work.

In gnu/build/install.scm it's not going to work.

The Guix high-level packaging stuff is not available build-side, only host-side.

Can you provide a patch of what you did?


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Re: create a symlink

[Rene]

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Hello Danny, sorry for delay.

I have updated my repository with commit
dc7d6d4ece30c7ab25e9f1927d64f2b409ab896c(version 14).

Danny Milosavljevic <dannym@scratchpost.org> writes:

> are you sure you put the call into guix/scripts/system.scm ?
>
> There are a lot of #$ things there already - should work.
>
> In gnu/build/install.scm it's not going to work.
>
> The Guix high-level packaging stuff is not available build-side, only host=
> -side.
>
> Can you provide a patch of what you did?
>

When doing `make` shows the error message:
--8<---------------cut here---------------start------------->8---
Backtrace:
          14 (primitive-load "/home/jin/guix/./build-aux/compile-all…")
In guix/build/compile.scm:
    158:6 13 (compile-files _ _ ("guix/scripts/system.scm" "gnu/b…") …)
   107:11 12 (load-files "." _ #:report-load _ #:debug-port _)
In ice-9/boot-9.scm:
  2800:17 11 (resolve-interface (guix scripts system) #:select _ # _ …)
In ice-9/threads.scm:
    390:8 10 (_ _)
In ice-9/boot-9.scm:
  2726:13  9 (_)
In ice-9/threads.scm:
    390:8  8 (_ _)
In ice-9/boot-9.scm:
  2994:20  7 (_)
   2312:4  6 (save-module-excursion _)
  3014:26  5 (_)
In unknown file:
           4 (primitive-load-path "guix/scripts/system" #<procedure …>)
In ice-9/eval.scm:
   191:35  3 (_ #f)
   191:27  2 (_ #f)
   223:20  1 (proc #<directory (guix scripts system) e2f050>)
In unknown file:
           0 (%resolve-variable (7 . ungexp) #<directory (guix scrip…>)

ERROR: In procedure %resolve-variable:
ungexp: unbound variable
Makefile:5463: recipe for target 'make-go' failed
make[2]: *** [make-go] Error 1
make[2]: Leaving directory '/home/jin/guix'
Makefile:4536: recipe for target 'all-recursive' failed
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory '/home/jin/guix'
Makefile:3078: recipe for target 'all' failed
make: *** [all] Error 2
--8<---------------cut here---------------end--------------->8---

Attached patch.


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From c0756c7dd90c038f5daddcf4893f57e9701ab033 Mon Sep 17 00:00:00 2001
From: Rene <ikhuuma@gmail.com>
Date: Thu, 7 Mar 2019 20:46:59 -0800
Subject: [PATCH] Add symlink.

---
 gnu/build/install.scm   | 19 +++++++++++++++++++
 guix/scripts/system.scm |  2 ++
 2 files changed, 21 insertions(+)

diff --git a/gnu/build/install.scm b/gnu/build/install.scm
index 9e30c0d23..202a9672d 100644
--- a/gnu/build/install.scm
+++ b/gnu/build/install.scm
@@ -27,6 +27,7 @@
             populate-root-file-system
             reset-timestamps
             register-closure
+            install-hurd
             populate-single-profile-directory))
 
 ;;; Commentary:
@@ -144,6 +145,24 @@ includes /etc, /var, /run, /bin/sh, etc., and all the symlinks to SYSTEM."
                 (try))
               (apply throw args)))))))
 
+(define (install-hurd pkg)
+  "Create a link to /gnu/store/..hurd-1.9 with the name /hurd."
+
+  ;; Add /hurd link.
+  (let ((link-1 (string-append target
+                                     "/hurd")))
+    (let try ()
+      (catch 'system-error
+        (lambda ()
+          (symlink pkg link-1))
+        (lambda args
+          ;; If /hurd already exists, overwrite it.
+          (if (= EEXIST (system-error-errno args))
+              (begin
+                (delete-file link-1)
+                (try))
+              (apply throw args)))))))
+
 (define (reset-timestamps directory)
   "Reset the timestamps of all the files under DIRECTORY, so that they appear
 as created and modified at the Epoch."
diff --git a/guix/scripts/system.scm b/guix/scripts/system.scm
index b688bb68c..be8e639b7 100644
--- a/guix/scripts/system.scm
+++ b/guix/scripts/system.scm
@@ -1151,3 +1151,5 @@ argument list and OPTS is the option alist."
 ;;; End:
 
 ;;; system.scm ends here
+
+(install-hurd #$hurd)
-- 
2.17.1


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-- 

Rene

Re: create a symlink

[Danny Milosavljevic]

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Hi Rene,

+++ b/guix/scripts/system.scm
@@ -1151,3 +1151,5 @@ argument list and OPTS is the option alist."
 ;;; End:
 
 ;;; system.scm ends here
+
+(install-hurd #$hurd)

That is not going to work there.

#$ unquotes from a build-side g-expression (similar to what "," would do in a quasiquote).
You are not in a g-expression at the position above.

In order to enter the g-expression environment, you could use #~ .

That would give you a lowerable object which someone has to lower in order
to get a derivation for it.  Then someone has to do derivation->output-path
in order to get an output path for that derivation.

Or put it into an existing block with #~ .

In your case, I would put the (install-hurd #$hurd) into a bootloader
module, I guess (inside "installer" there--which has a #~ ).

What is supposed to load the "/hurd" that would be created ?

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Re: create a symlink

[Rene]

Hello,

Danny Milosavljevic <dannym@scratchpost.org> writes:

>
> What is supposed to load the "/hurd" that would be created ?
>

After starting GNU Mach microkernel, the hurd translators are required to start
the operating system.

At the moment all components like gnumach, hurd servers point to /hurd.

Maybe there is a way to avoid links?

-- 

Rene

Re: create a symlink

[Danny Milosavljevic]

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Hi Rene,

On Fri, 08 Mar 2019 15:13:13 -0600
Rene <ikhuuma@gmail.com> wrote:

> Danny Milosavljevic <dannym@scratchpost.org> writes:
> 
> >
> > What is supposed to load the "/hurd" that would be created ?
> >  
> 
> After starting GNU Mach microkernel, the hurd translators are required to start
> the operating system.
> 
> At the moment all components like gnumach, hurd servers point to /hurd.
> 
> Maybe there is a way to avoid links?

I see.  I ask because usually the part that loads that can be adapted and
is also a better place to do the adaption in the first place--instead of
hard-coding "/hurd".  After all, we want eventually to have the ability
to roll back the system by selecting a previous generation in the
bootloader menu again.  That doesn't work all that well with the "/hurd"
link.

But as far as I understand, you boot Debian/Hurd or something and then
it loads Guix, right?

In that case, we can understand the GNU Mach microkernel as a bootloader
(from our vantage point) and thus emit the /hurd link in the "bootloader"
configuration.  It's not that clean, but it works (sans rollback, though).

Cleaner would be to also boot Guix's gnumach microkernel.

It seems that https://www.gnu.org/software/hurd/grub.html documents
how to get grub to boot mach and then hurd--and it seems that there, the
paths are specified.

It should be easy to adapt gnu/bootloader/grub.scm's grub-configuration-file
to emit those and then reconfigure.

(Later, we could add "multiboot" and "modules" to <menu-entry> in
gnu/bootloader.scm)

However, it's a dangerous part to modify since this part cannot be rolled
back easily.  So don't make a typo ;)

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Re: create a symlink

[Rene]

Hi,

Danny Milosavljevic <dannym@scratchpost.org> writes:

>
> But as far as I understand, you boot Debian/Hurd or something and then
> it loads Guix, right?
>

Yes, I use Guix as package manager like another linux distro.

I currently use `./pre-inst-env guix system init doc/os-config-hurd.scm
/guix`, where /guix is an empty partition to populate GuixSD os.

>
> It should be easy to adapt gnu/bootloader/grub.scm's grub-configuration-file
> to emit those and then reconfigure.
>
> (Later, we could add "multiboot" and "modules" to <menu-entry> in
> gnu/bootloader.scm)
>
> However, it's a dangerous part to modify since this part cannot be rolled
> back easily.  So don't make a typo ;)
>

I get It.

I found a conversation in bug-hurd, maybe it will work to avoid links like /hurd.
http://lists.gnu.org/archive/html/bug-hurd/2015-07/msg00002.html

How I can change "/hurd/" by "/gnu/store/abc..-hurd-0.9/hurd/" in
<hurd/paths.h> through Guix?

--8<---------------cut here---------------start------------->8---
/* Hurd servers are specified by symbols _HURD_FOO,
   the canonical pathname being /hurd/foo.  */

#define       _HURD           "/hurd/"
#define _HURD_STARTUP   _HURD "startup"
#define _HURD_PROC       _HURD "proc"
#define _HURD_AUTH  _HURD "auth"
--8<---------------cut here---------------end--------------->8---


-- 

Rene

Re: create a symlink

[Danny Milosavljevic]

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Hi Rene,

On Tue, 12 Mar 2019 14:57:59 -0600
Rene <ikhuuma@gmail.com> wrote:

> How I can change "/hurd/" by "/gnu/store/abc..-hurd-0.9/hurd/" in
> <hurd/paths.h> through Guix?
> 
> --8<---------------cut here---------------start------------->8---
> /* Hurd servers are specified by symbols _HURD_FOO,
>    the canonical pathname being /hurd/foo.  */
> 
> #define       _HURD           "/hurd/"
> #define _HURD_STARTUP   _HURD "startup"
> #define _HURD_PROC       _HURD "proc"
> #define _HURD_AUTH  _HURD "auth"
> --8<---------------cut here---------------end--------------->8---

Hmm, try to patch it out of the source code.

Modify /gnu/packages/hurd.scm to be something like:

(define-public hurd
  (package
    [...]
    (arguments
     `(#:phases
       (modify-phases %standard-phases
         (add-after 'unpack 'patch-paths
           (lambda* (#:key outputs #:allow-other-keys)
             (substitute* "hurd/paths.h"
              (("\"/hurd/\"")
                (string-append "\"" (assoc-ref outputs "out") "\"")))
             #t))
         [...]


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Re: create a symlink

[Ludovic Courtès]

Hello,

Rene <ikhuuma@gmail.com> skribis:

> How I can change "/hurd/" by "/gnu/store/abc..-hurd-0.9/hurd/" in
> <hurd/paths.h> through Guix?

I think /hurd is hard to avoid; it’s akin to /bin/sh, which is also
hard-coded in libc (for the ‘system’ function).  As you found out, you’d
need to change macros in libc headers, which means that libc could only
talk to a specific instance of the Hurd servers.  Furthermore, /hurd
needs to be writable.

So I would recommend keeping /hurd, at least as a first approach.

Happy hacking!

Ludo’.

Re: create a symlink

[Danny Milosavljevic]

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On Wed, 13 Mar 2019 15:52:36 +0100
Ludovic Courtès <ludo@gnu.org> wrote:

> Hello,
> 
> Rene <ikhuuma@gmail.com> skribis:
> 
> > How I can change "/hurd/" by "/gnu/store/abc..-hurd-0.9/hurd/" in
> > <hurd/paths.h> through Guix?  
> 
> I think /hurd is hard to avoid; it’s akin to /bin/sh, which is also
> hard-coded in libc (for the ‘system’ function).  As you found out, you’d
> need to change macros in libc headers, which means that libc could only
> talk to a specific instance of the Hurd servers.  Furthermore, /hurd
> needs to be writable.
> 
> So I would recommend keeping /hurd, at least as a first approach.

In that case, /hurd could be handled like we handle /run/booted-system .

Rene could use service extension like

  (service-extension boot-service-type hurd-boot-gexp)

in order to create the "/hurd" symlink (in hurd-boot-gexp).

That is, if the Hurd can boot that far (until the root filesystem is mounted).

In fact, as a hack, we could create a dummy service that does the service
extension and use it for the Hurd.

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Re: create a symlink

[Rene]

Hello Danny,

Danny Milosavljevic <dannym@scratchpost.org> writes:
>
> In that case, /hurd could be handled like we handle /run/booted-system .
>

As I understand Guix, /run/booted-system is created during the
boot(activation) process; however, I think that to perform the
activation there should already be /hurd (binaries like ext2fs.static,exec..).

> Rene could use service extension like
>
>   (service-extension boot-service-type hurd-boot-gexp)
>
> in order to create the "/hurd" symlink (in hurd-boot-gexp).
>
> That is, if the Hurd can boot that far (until the root filesystem is mounted).
>
> In fact, as a hack, we could create a dummy service that does the service
> extension and use it for the Hurd.
>

For now, I did the following:

--8<---------------cut here---------------start------------->8---
lrwxr-xr-x  1 root root    37 Mar 28 00:19 bin -> /var/guix/profiles/system/profile/bin
drwxr-xr-x  3 root root  4096 Mar 28 00:19 boot
drwxr-xr-x  4 root root  4096 Mar 27 17:31 dev
drwxr-xr-x  3 root root  4096 Mar 27 18:05 etc
drwxr-xr-x  3 root root  4096 Mar 28 00:15 gnu
drwxr-xr-x  3 root root  4096 Mar 27 17:31 home
lrwxr-xr-x  1 root root    38 Mar 28 00:19 hurd -> /var/guix/profiles/system/profile/hurd
drwxr-xr-x  2 root root  4096 Mar 28 00:19 lib
lrwxr-xr-x  1 root root    41 Mar 28 00:19 libexec -> /var/guix/profiles/system/profile/libexec
drwx------  2 root root 16384 Mar 28 00:10 lost+found
drwxr-xr-x  2 root root  4096 Mar 28 00:19 mnt
dr-xr-xr-x  0 root root     0 Dec 31  1969 proc
drwxr-xr-x  3 root root  4096 Mar 27 17:35 root
drwxr-xr-x  3 root root  4096 Mar 27 17:31 run
lrwxr-xr-x  1 root root    38 Mar 28 00:19 sbin -> /var/guix/profiles/system/profile/sbin
drwxr-xr-x  3 root root  4096 Mar 28 00:19 servers
drwxrwxrwt  2 root root  4096 Mar 27 18:01 tmp
drwxr-xr-x 10 root root  4096 Mar 27 17:31 var
--8<---------------cut here---------------end--------------->8---

In this way the gnumach kernel can find /hurd and the binaries needed to
start the whole system.

On the other hand, in linux there is `--system` argument, how does this
argument work?, Is there a script that uses it?. To test `--system`, I
removed it from my linux system and when loging in with my user it does not
detect any command.

--8<---------------cut here---------------start------------->8---
BOOT_IMAGE=/gnu/store/fiqgyafknihbvmz4j62ddb67p79kfcbk-linux-libre-4.19.13/bzImage --root=my-root --system=/var/guix/profiles/system-87-link --load=/var/guix/profiles/system-87-link/boot
--8<---------------cut here---------------end--------------->8---

Thank you
-- 

Rene

Re: create a symlink

[Chris Marusich]

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Hi Rene,

Rene <ikhuuma@gmail.com> writes:

> On the other hand, in linux there is `--system` argument, how does this
> argument work?, Is there a script that uses it?. To test `--system`, I
> removed it from my linux system and when loging in with my user it does not
> detect any command.
>
> BOOT_IMAGE=/gnu/store/fiqgyafknihbvmz4j62ddb67p79kfcbk-linux-libre-4.19.13/bzImage --root=my-root --system=/var/guix/profiles/system-87-link --load=/var/guix/profiles/system-87-link/boot

To see how the Linux kernel argument "--system" is used, check out the
"boot-time-system" procedure in gnu/build/activation.scm.  Ultimately
this is used by the activation-service-type, defined in
gnu/services.scm.

In short, when the system boots, the activation service will atomically
flip the "/run/current-system" symlink. and then run all the activation
scripts defined by services that extend the activation service.  The
value of "--system" can be overridden by setting the GUIX_NEW_SYSTEM
environment variable; in fact, we do that in the switch-to-system
procedure in guix/scripts/system.scm, which is used when running
commands like "guix system reconfigure", "guix system roll-back," and
"guix system switch-generation".

Hopefully that helps!

-- 
Chris

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