environment: Add --link-profile.

This change is motivated by attempts to run programs (like GNU IceCat) within
containers.  The 'fontconfig' program, for example, is configured explicitly
to check ~/.guix-profile for additional fonts.

There were no existing container tests in 'tests/guix-environment.sh', but I
added one anyway for this change.

* doc/guix.texi (Invoking guix environment): Add '--link-profile'.
* guix/scripts/environment.scm (show-help): Add '--link-profile'.
(%options): Add 'link-profile' as '#\P', assigned to 'link-profile?'.
(link-environment): New procedure.
(launch-environment/container): Use it when 'link-profile?'.
[link-profile?]: New parameter.
(guix-environment): Leave when '--link-prof' but not '--container'.  Add
'#:link-profile?' argument to 'launch-environment/container' application.
* tests/guix-environment-container.sh: New '--link-profile' test.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>
master
Mike Gerwitz 2018-01-25 22:29:15 -05:00 committed by Ludovic Courtès
parent 99654a1685
commit 07ec349229
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GPG Key ID: 090B11993D9AEBB5
3 changed files with 70 additions and 8 deletions

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@ -46,7 +46,8 @@ Copyright @copyright{} 2017 Andy Wingo@*
Copyright @copyright{} 2017, 2018 Arun Isaac@*
Copyright @copyright{} 2017 nee@*
Copyright @copyright{} 2018 Rutger Helling@*
Copyright @copyright{} 2018 Oleg Pykhalov
Copyright @copyright{} 2018 Oleg Pykhalov@*
Copyright @copyright{} 2018 Mike Gerwitz
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
@ -1572,7 +1573,7 @@ To be able to use such full names for the TrueType fonts installed in
your Guix profile, you need to extend the font path of the X server:
@example
xset +fp ~/.guix-profile/share/fonts/truetype
xset +fp `readlink -f ~/.guix-profile/share/fonts/truetype`
@end example
@cindex @code{xlsfonts}
@ -7296,6 +7297,22 @@ For containers, share the network namespace with the host system.
Containers created without this flag only have access to the loopback
device.
@item --link-profile
@itemx -P
For containers, link the environment profile to
@file{~/.guix-profile} within the container. This is equivalent to
running the command @command{ln -s $GUIX_ENVIRONMENT ~/.guix-profile}
within the container. Linking will fail and abort the environment if
the directory already exists, which will certainly be the case if
@command{guix environment} was invoked in the user's home directory.
Certain packages are configured to look in
@code{~/.guix-profile} for configuration files and data;@footnote{For
example, the @code{fontconfig} package inspects
@file{~/.guix-profile/share/fonts} for additional fonts.}
@code{--link-profile} allows these programs to behave as expected within
the environment.
@item --expose=@var{source}[=@var{target}]
For containers, expose the file system @var{source} from the host system
as the read-only file system @var{target} within the container. If

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@ -1,6 +1,7 @@
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2014, 2015, 2018 David Thompson <davet@gnu.org>
;;; Copyright © 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2018 Mike Gerwitz <mtg@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
@ -159,6 +160,9 @@ COMMAND or an interactive shell in that environment.\n"))
-C, --container run command within an isolated container"))
(display (G_ "
-N, --network allow containers to access the network"))
(display (G_ "
-P, --link-profile link environment profile to ~/.guix-profile within
an isolated container"))
(display (G_ "
--share=SPEC for containers, share writable host file system
according to SPEC"))
@ -243,6 +247,9 @@ COMMAND or an interactive shell in that environment.\n"))
(option '(#\N "network") #f #f
(lambda (opt name arg result)
(alist-cons 'network? #t result)))
(option '(#\P "link-profile") #f #f
(lambda (opt name arg result)
(alist-cons 'link-profile? #t result)))
(option '("share") #t #f
(lambda (opt name arg result)
(alist-cons 'file-system-mapping
@ -404,18 +411,20 @@ environment variables are cleared before setting the new ones."
((_ . status) status)))))
(define* (launch-environment/container #:key command bash user-mappings
profile paths network?)
profile paths link-profile? network?)
"Run COMMAND within a container that features the software in PROFILE.
Environment variables are set according to PATHS, a list of native search
paths. The global shell is BASH, a file name for a GNU Bash binary in the
store. When NETWORK?, access to the host system network is permitted.
USER-MAPPINGS, a list of file system mappings, contains the user-specified
host file systems to mount inside the container."
host file systems to mount inside the container. LINK-PROFILE? creates a
symbolic link from ~/.guix-profile to the environment profile."
(mlet %store-monad ((reqs (inputs->requisites
(list (direct-store-path bash) profile))))
(return
(let* ((cwd (getcwd))
(passwd (getpwuid (getuid)))
(let* ((cwd (getcwd))
(passwd (getpwuid (getuid)))
(home-dir (passwd:dir passwd))
;; Bind-mount all requisite store items, user-specified mappings,
;; /bin/sh, the current working directory, and possibly networking
;; configuration files within the container.
@ -460,8 +469,13 @@ host file systems to mount inside the container."
;; Create a dummy home directory under the same name as on the
;; host.
(mkdir-p (passwd:dir passwd))
(setenv "HOME" (passwd:dir passwd))
(mkdir-p home-dir)
(setenv "HOME" home-dir)
;; If requested, link $GUIX_ENVIRONMENT to $HOME/.guix-profile;
;; this allows programs expecting that path to continue working as
;; expected within a container.
(when link-profile? (link-environment profile home-dir))
;; Create a dummy /etc/passwd to satisfy applications that demand
;; to read it, such as 'git clone' over SSH, a valid use-case when
@ -491,6 +505,18 @@ host file systems to mount inside the container."
(delq 'net %namespaces) ; share host network
%namespaces)))))))
(define (link-environment profile home-dir)
"Create a symbolic link from HOME-DIR/.guix-profile to PROFILE."
(let ((profile-dir (string-append home-dir "/.guix-profile")))
(catch 'system-error
(lambda ()
(symlink profile profile-dir))
(lambda args
(if (= EEXIST (system-error-errno args))
(leave (G_ "cannot link profile: '~a' already exists within container~%")
profile-dir)
(apply throw args))))))
(define (environment-bash container? bootstrap? system)
"Return a monadic value in the store monad for the version of GNU Bash
needed in the environment for SYSTEM, if any. If CONTAINER? is #f, return #f.
@ -564,6 +590,7 @@ message if any test fails."
(let* ((opts (parse-args args))
(pure? (assoc-ref opts 'pure))
(container? (assoc-ref opts 'container?))
(link-prof? (assoc-ref opts 'link-profile?))
(network? (assoc-ref opts 'network?))
(bootstrap? (assoc-ref opts 'bootstrap?))
(system (assoc-ref opts 'system))
@ -597,6 +624,9 @@ message if any test fails."
(when container? (assert-container-features))
(when (and (not container?) link-prof?)
(leave (G_ "'--link-profile' cannot be used without '--container'~%")))
(with-store store
(set-build-options-from-command-line store opts)
@ -646,6 +676,7 @@ message if any test fails."
#:user-mappings mappings
#:profile profile
#:paths paths
#:link-profile? link-prof?
#:network? network?)))
(else
(return

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@ -97,6 +97,20 @@ grep -e "$NIX_STORE_DIR/.*-bash" $tmpdir/mounts # bootstrap bash
rm $tmpdir/mounts
# Make sure 'GUIX_ENVIRONMENT' is linked to '~/.guix-profile' when requested
# within a container.
(
linktest='(exit (string=? (getenv "GUIX_ENVIRONMENT")
(readlink (string-append (getenv "HOME") "/.guix-profile"))))'
cd "$tmpdir" \
&& guix environment --bootstrap --container --link-profile \
--ad-hoc guile-bootstrap --pure \
-- guile -c "$linktest"
)
# Check the exit code.
abnormal_exit_code="
(use-modules (system foreign))
;; Purposely make Guile crash with a segfault. :)