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system: Add 'locale-libcs' field.

* gnu/system/locale.scm (localedef-command)[maybe-version-directory]:
  New procedure.
  Use it.
  (locale-directory): Rename to...
  (single-locale-directory): ... this.  Check the version of LIBC to
  determine whether to create a "X.Y" sub-directory or to make it a
  symlink to ".".  Add the version number in the derivation name.
  (locale-directory): New procedure.
  (%default-locale-libcs): New variable.
* gnu/system.scm (<operating-system>)[locale-libcs]: New field.
  (operating-system-locale-directory): Pass it to 'locale-directory'.
* doc/guix.texi (operating-system Reference): Document 'locale-libcs'.
  (Locales)[Locale Data Compatibility Considerations]: New section.
version-0.9.0
Ludovic Courtès 6 years ago
parent
commit
34760ae703
  1. 56
      doc/guix.texi
  2. 6
      gnu/system.scm
  3. 62
      gnu/system/locale.scm

56
doc/guix.texi

@ -5562,6 +5562,11 @@ Library Reference Manual}). @xref{Locales}, for more information.
The list of locale definitions to be compiled and that may be used at
run time. @xref{Locales}.
@item @code{locale-libcs} (default: @code{(list @var{glibc})})
The list of GNU@tie{}libc packages whose locale data and tools are used
to build the locale definitions. @xref{Locales}, for compatibility
considerations that justify this option.
@item @code{name-service-switch} (default: @var{%default-nss})
Configuration of libc's name service switch (NSS)---a
@code{<name-service-switch>} object. @xref{Name Service Switch}, for
@ -6020,6 +6025,57 @@ instance it has @code{uk_UA.utf8} but @emph{not}, say,
@code{uk_UA.UTF-8}.
@end defvr
@subsubsection Locale Data Compatibility Considerations
@cindex incompatibility, of locale data
@code{operating-system} declarations provide a @code{locale-libcs} field
to specify the GNU@tie{}libc packages that are used to compile locale
declarations (@pxref{operating-system Reference}). ``Why would I
care?'', you may ask. Well, it turns out that the binary format of
locale data is occasionally incompatible from one libc version to
another.
@c See <https://sourceware.org/ml/libc-alpha/2015-09/msg00575.html>
@c and <https://lists.gnu.org/archive/html/guix-devel/2015-08/msg00737.html>.
For instance, a program linked against libc version 2.21 is unable to
read locale data produced with libc 2.22; worse, that program
@emph{aborts} instead of simply ignoring the incompatible locale
data@footnote{Versions 2.23 and later of GNU@tie{}libc will simply skip
the incompatible locale data, which is already an improvement.}.
Similarly, a program linked against libc 2.22 can read most, but not
all, the locale data from libc 2.21 (specifically, @code{LC_COLLATE}
data is incompatible); thus calls to @code{setlocale} may fail, but
programs will not abort.
The ``problem'' in GuixSD is that users have a lot of freedom: They can
choose whether and when to upgrade software in their profiles, and might
be using a libc version different from the one the system administrator
used to build the system-wide locale data.
Fortunately, unprivileged users can also install their own locale data
and define @var{GUIX_LOCPATH} accordingly (@pxref{locales-and-locpath,
@code{GUIX_LOCPATH} and locale packages}).
Still, it is best if the system-wide locale data at
@file{/run/current-system/locale} is built for all the libc versions
actually in use on the system, so that all the programs can access
it---this is especially crucial on a multi-user system. To do that, the
administrator can specify several libc packages in the
@code{locale-libcs} field of @code{operating-system}:
@example
(use-package-modules base)
(operating-system
;; @dots{}
(locale-libcs (list glibc-2.21 (canonical-package glibc))))
@end example
This example would lead to a system containing locale definitions for
both libc 2.21 and the current version of libc in
@file{/run/current-system/locale}.
@node Services
@subsection Services

6
gnu/system.scm

@ -76,6 +76,7 @@
operating-system-timezone
operating-system-locale
operating-system-locale-definitions
operating-system-locale-libcs
operating-system-mapped-devices
operating-system-file-systems
operating-system-activation-script
@ -144,6 +145,8 @@
(default "en_US.utf8"))
(locale-definitions operating-system-locale-definitions ; list of <locale-definition>
(default %default-locale-definitions))
(locale-libcs operating-system-locale-libcs ; list of <packages>
(default %default-locale-libcs))
(name-service-switch operating-system-name-service-switch ; <name-service-switch>
(default %default-nss))
@ -643,7 +646,8 @@ listed in OS. The C library expects to find it under
(raise (condition
(&message (message "system locale lacks a definition")))))
(locale-directory (operating-system-locale-definitions os)))
(locale-directory (operating-system-locale-definitions os)
#:libcs (operating-system-locale-libcs os)))
(define (kernel->grub-label kernel)
"Return a label for the GRUB menu entry that boots KERNEL."

62
gnu/system/locale.scm

@ -18,11 +18,15 @@
(define-module (gnu system locale)
#:use-module (guix gexp)
#:use-module (guix store)
#:use-module (guix monads)
#:use-module (guix records)
#:use-module (guix packages)
#:use-module (guix utils)
#:use-module (gnu packages base)
#:use-module (gnu packages compression)
#:use-module (srfi srfi-26)
#:use-module (ice-9 match)
#:export (locale-definition
locale-definition?
locale-definition-name
@ -31,6 +35,7 @@
locale-directory
%default-locale-libcs
%default-locale-definitions))
;;; Commentary:
@ -50,6 +55,15 @@
(define* (localedef-command locale
#:key (libc (canonical-package glibc)))
"Return a gexp that runs 'localedef' from LIBC to build LOCALE."
(define (maybe-version-directory)
;; XXX: For libc prior to 2.22, GuixSD did not store locale data in a
;; version-specific sub-directory. Check whether this is the case.
;; TODO: Remove this hack once libc 2.21 is buried.
(let ((version (package-version libc)))
(if (version>=? version "2.22")
(list version "/")
'())))
#~(begin
(format #t "building locale '~a'...~%"
#$(locale-definition-name locale))
@ -58,20 +72,29 @@
"-i" #$(locale-definition-source locale)
"-f" #$(locale-definition-charset locale)
(string-append #$output "/"
#$(package-version libc) "/"
#$@(maybe-version-directory)
#$(locale-definition-name locale))))))
(define* (locale-directory locales
#:key (libc (canonical-package glibc)))
(define* (single-locale-directory locales
#:key (libc (canonical-package glibc)))
"Return a directory containing all of LOCALES for LIBC compiled.
Because locale data formats are incompatible when switching from one libc to
another, locale data is put in a sub-directory named after the 'version' field
of LIBC."
(define version
(package-version libc))
(define build
#~(begin
(mkdir #$output)
(mkdir (string-append #$output "/" #$(package-version libc)))
;; XXX: For libcs < 2.22, locale data is stored in the top-level
;; directory.
;; TODO: Remove this hack once libc 2.21 is buried.
#$(if (version>=? version "2.22")
#~(mkdir (string-append #$output "/" #$version))
#~(symlink "." (string-append #$output "/" #$version)))
;; 'localedef' executes 'gzip' to access compressed locale sources.
(setenv "PATH" (string-append #$gzip "/bin"))
@ -80,9 +103,38 @@ of LIBC."
(and #$@(map (cut localedef-command <> #:libc libc)
locales)))))
(gexp->derivation "locale" build
(gexp->derivation (string-append "locale-" version) build
#:local-build? #t))
(define* (locale-directory locales
#:key (libcs %default-locale-libcs))
"Return a locale directory containing all of LOCALES for each libc package
listed in LIBCS.
It is useful to list more than one libc when willing to support
already-installed packages built against a different libc since the locale
data format changes between libc versions."
(match libcs
((libc)
(single-locale-directory locales #:libc libc))
((libcs ..1)
(mlet %store-monad ((dirs (mapm %store-monad
(lambda (libc)
(single-locale-directory locales
#:libc libc))
libcs)))
(gexp->derivation "locale-multiple-versions"
#~(begin
(use-modules (guix build union))
(union-build #$output (list #$@dirs)))
#:modules '((guix build union))
#:local-build? #t
#:substitutable? #f)))))
(define %default-locale-libcs
;; The libcs for which we build locales by default.
(list (canonical-package glibc)))
(define %default-locale-definitions
;; Arbitrary set of locales that are built by default. They are here mostly
;; to facilitate first-time use to some people, while others may have to add

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