Subject: Re: [bug#39807] [PATCH] guix: pack: Only wrap executable files.

From: Eric Bavier <[email-masked]>
Date: Mon, 27 Jul 2020 16:42:00 -0500

Patch rebased on latest master attached.  The new test implements a
small proxy for the behavior exhibited by git and its libexec scripts.

Call for help: the test does not pass!  I get this error:

  hello: run.c:284: exec_in_user_namespace: Unexpected error: No such
file or directory.

Could someone more familiar with user namespaces, etc help me work
this out?

`~Eric
From b31e63c3668e5163eba40f7815ccae19cb2af236 Mon Sep 17 00:00:00 2001
From: Eric Bavier <[email-masked]>
Date: Mon, 24 Feb 2020 23:47:02 -0600
Subject: [PATCH] guix: pack: Only wrap executable files.

* guix/scripts/pack.scm (wrapped-package)<build>: Build wrappers for
executable files and symlink others.
* tests/guix-pack-relocatable.sh: Test relocatable example of mixed
executable and non-executable files.
---
 guix/scripts/pack.scm          | 31 ++++++++++++++++++++++---------
 tests/guix-pack-relocatable.sh | 31 +++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 9 deletions(-)

diff --git a/guix/scripts/pack.scm b/guix/scripts/pack.scm
index 5fb6aaae0c..1b9609753d 100644
--- a/guix/scripts/pack.scm
+++ b/guix/scripts/pack.scm
@@ -5,6 +5,7 @@
 ;;; Copyright © 2018 Chris Marusich <[email-masked]>
 ;;; Copyright © 2018 Efraim Flashner <[email-masked]>
 ;;; Copyright © 2020 Tobias Geerinckx-Rice <[email-masked]>
+;;; Copyright © 2020 Eric Bavier <[email-masked]>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -747,11 +748,12 @@ last resort for relocation."
                               (guix elf)))
       #~(begin
           (use-modules (guix build utils)
-                       ((guix build union) #:select (relative-file-name))
+                       ((guix build union) #:select (symlink-relative))
                        (guix elf)
                        (ice-9 binary-ports)
                        (ice-9 ftw)
                        (ice-9 match)
+                       (ice-9 receive)
                        (srfi srfi-1)
                        (rnrs bytevectors))
 
@@ -847,16 +849,27 @@ last resort for relocation."
           (mkdir target)
           (for-each (lambda (file)
                       (unless (member file '("." ".." "bin" "sbin" "libexec"))
-                        (let ((file* (string-append input "/" file)))
-                          (symlink (relative-file-name target file*)
-                                   (string-append target "/" file)))))
+                        (symlink-relative (string-append input  "/" file)
+                                          (string-append target "/" file))))
                     (scandir input))
 
-          (for-each build-wrapper
-                    ;; Note: Trailing slash in case these are symlinks.
-                    (append (find-files (string-append input "/bin/"))
-                            (find-files (string-append input "/sbin/"))
-                            (find-files (string-append input "/libexec/")))))))
+          (receive (executables others)
+              (partition executable-file?
+			 ;; Note: Trailing slash in case these are symlinks.
+                         (append (find-files (string-append input "/bin/"))
+                                 (find-files (string-append input "/sbin/"))
+                                 (find-files (string-append input "/libexec/"))))
+            ;; Wrap only executables, since the wrapper will eventually need
+            ;; to execve them.  E.g. git's "libexec" directory contains many
+            ;; shell scripts that are source'd from elsewhere, which fails if
+            ;; they are wrapped.
+            (for-each build-wrapper executables)
+            ;; Link any other non-executable files
+            (for-each (lambda (old)
+                        (let ((new (string-append target (strip-store-prefix old))))
+                          (mkdir-p (dirname new))
+                          (symlink-relative old new)))
+                      others)))))
 
   (computed-file (string-append
                   (cond ((package? package)
diff --git a/tests/guix-pack-relocatable.sh b/tests/guix-pack-relocatable.sh
index 52d7212594..2ed497027d 100644
--- a/tests/guix-pack-relocatable.sh
+++ b/tests/guix-pack-relocatable.sh
@@ -1,5 +1,6 @@
 # GNU Guix --- Functional package management for GNU
 # Copyright © 2018, 2019, 2020 Ludovic Courtès <[email-masked]>
+# Copyright © 2020 Eric Bavier <[email-masked]>
 #
 # This file is part of GNU Guix.
 #
@@ -99,6 +100,7 @@ case "`uname -m`" in
 	GUIX_EXECUTION_ENGINE="fakechroot"
 	"$test_directory/Bin/sed" --version > "$test_directory/output"
 	grep 'GNU sed' "$test_directory/output"
+	unset GUIX_EXECUTION_ENGINE
 
 	chmod -Rf +w "$test_directory"; rm -rf "$test_directory"/*
 	;;
@@ -111,8 +113,37 @@ esac
 tarball="`guix pack -R -S /share=share groff:doc`"
 (cd "$test_directory"; tar xvf "$tarball")
 test -d "$test_directory/share/doc/groff/html"
+chmod -Rf +w "$test_directory"; rm -rf "$test_directory"/*
 
 # Ensure '-R' applies to propagated inputs.  Failing to do that, it would fail
 # with a profile collision error in this case because 'python-scipy'
 # propagates 'python-numpy'.  See <https://bugs.gnu.org/42510>.
 guix pack -RR python-numpy python-scipy --no-grafts -n
+
+# Check that packages that mix executable and support files (e.g. git) in the
+# "binary" directories still work after wrapped.
+cat >"$test_directory/manifest.scm" <<'EOF'
+(use-modules (guix) (guix profiles)
+             (gnu packages bootstrap))
+(manifest
+ (list (manifest-entry
+	(name "test") (version "0")
+	(item (file-union "test"
+			  `(("bin/hello"
+			     ,(program-file
+                               "hello"
+                               #~(format #t "~d~%" (load "../libexec/msg"))
+                               #:guile %bootstrap-guile))
+			    ("libexec/msg"
+			     ,(plain-file "msg" "42"))))))))
+EOF
+tarball="`guix pack $relocatable_option -S /opt= -m $test_directory/manifest.scm`"
+(cd "$test_directory"; tar xvf "$tarball")
+do_test='"$test_directory/opt/bin/hello" >"$test_directory/output"'
+if unshare -r true		# Are user namespaces supported?
+then
+    unshare -mrf sh -c 'mount -t tmpfs none "$STORE_PARENT"; '"$do_test"
+else
+    ( $do_test )
+fi
+test "`cat $test_directory/output`" = "42"
-- 
2.27.0