From 81c1e187fd98b3a4cec9a15fd3c4d1fd0471ad49 Mon Sep 17 00:00:00 2001
From: Bogdan Drozdowski <>
Date: Thu, 29 Dec 2022 19:46:41 +0100
Subject: [PATCH] Allow user-defined options for tar

---
 doc/automake.texi    |  6 +++++-
 m4/tar.m4            | 20 +++++++++---------
 t/list-of-tests.mk   |  1 +
 t/tar-opts-envvar.sh | 48 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 64 insertions(+), 11 deletions(-)
 create mode 100644 t/tar-opts-envvar.sh

diff --git a/doc/automake.texi b/doc/automake.texi
index 48744e24f..d53caef07 100644
--- a/doc/automake.texi
+++ b/doc/automake.texi
@@ -8622,7 +8622,11 @@ More precisely, the gzipped @code{tar} file is named
 @c See automake #9822.
 @vindex TAR
 You can set the environment variable @code{TAR} to override the tar
-program used; it defaults to @code{tar}.  @xref{The Types of
+program used; it defaults to @code{tar}.
+You can set the environment variable @code{TAR_OPTIONS} to specify
+additional options to pass to the tar program when creating packages
+and @code{UNTAR_OPTIONS} for additional options to pass when unpacking.
+@xref{The Types of
 Distributions}, for how to generate other kinds of archives.
 
 For the most part, the files to distribute are automatically found by
diff --git a/m4/tar.m4 b/m4/tar.m4
index 8f4d2f213..ca00555eb 100644
--- a/m4/tar.m4
+++ b/m4/tar.m4
@@ -29,7 +29,7 @@ AC_SUBST([AMTAR], ['$${TAR-tar}'])
 _am_tools='gnutar m4_if([$1], [ustar], [plaintar]) pax cpio none'
 
 m4_if([$1], [v7],
-  [am__tar='$${TAR-tar} chof - "$$tardir"' am__untar='$${TAR-tar} xf -'],
+  [am__tar='$${TAR-tar} c $${TAR_OPTIONS} -hof - "$$tardir"' am__untar='$${TAR-tar} x $${UNTAR_OPTIONS} -f -'],
 
   [m4_case([$1],
     [ustar],
@@ -81,17 +81,17 @@ m4_if([$1], [v7],
       for _am_tar in tar gnutar gtar; do
         AM_RUN_LOG([$_am_tar --version]) && break
       done
-      am__tar="$_am_tar --format=m4_if([$1], [pax], [posix], [$1]) -chf - "'"$$tardir"'
-      am__tar_="$_am_tar --format=m4_if([$1], [pax], [posix], [$1]) -chf - "'"$tardir"'
-      am__untar="$_am_tar -xf -"
+      am__tar="$_am_tar $${TAR_OPTIONS} --format=m4_if([$1], [pax], [posix], [$1]) -chf - "'"$$tardir"'
+      am__tar_="$_am_tar $${TAR_OPTIONS} --format=m4_if([$1], [pax], [posix], [$1]) -chf - "'"$tardir"'
+      am__untar="$_am_tar -x $${UNTAR_OPTIONS} -f -"
       ;;
     plaintar)
       # Must skip GNU tar: if it does not support --format= it doesn't create
       # ustar tarball either.
       (tar --version) >/dev/null 2>&1 && continue
-      am__tar='tar chf - "$$tardir"'
-      am__tar_='tar chf - "$tardir"'
-      am__untar='tar xf -'
+      am__tar='tar c $${TAR_OPTIONS} -hf - "$$tardir"'
+      am__tar_='tar c $${TAR_OPTIONS} -hf - "$tardir"'
+      am__untar='tar x $${UNTAR_OPTIONS} -f -'
       ;;
     pax)
       am__tar='pax -L -x $1 -w "$$tardir"'
@@ -99,9 +99,9 @@ m4_if([$1], [v7],
       am__untar='pax -r'
       ;;
     cpio)
-      am__tar='find "$$tardir" -print | cpio -o -H $1 -L'
-      am__tar_='find "$tardir" -print | cpio -o -H $1 -L'
-      am__untar='cpio -i -H $1 -d'
+      am__tar='find "$$tardir" -print | cpio $${CPIO_OPTIONS} -o -H $1 -L'
+      am__tar_='find "$tardir" -print | cpio $${CPIO_OPTIONS} -o -H $1 -L'
+      am__untar='cpio $${UNCPIO_OPTIONS} -i -H $1 -d'
       ;;
     none)
       am__tar=false
diff --git a/t/list-of-tests.mk b/t/list-of-tests.mk
index d82cf9c4d..1b2d91cfe 100644
--- a/t/list-of-tests.mk
+++ b/t/list-of-tests.mk
@@ -1207,6 +1207,7 @@ t/tags-lisp-space.sh \
 t/tags-pr12372.sh \
 t/tar-ustar.sh \
 t/tar-pax.sh \
+t/tar-opts-envvar.sh \
 t/tar-opts-errors.sh \
 t/tar-ustar-id-too-high.sh \
 t/tar-override.sh \
diff --git a/t/tar-opts-envvar.sh b/t/tar-opts-envvar.sh
new file mode 100644
index 000000000..73836edbc
--- /dev/null
+++ b/t/tar-opts-envvar.sh
@@ -0,0 +1,48 @@
+#! /bin/sh
+# Copyright (C) 2004-2022 Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+# Check if passing options from environment to 'tar' works.
+
+. test-init.sh
+
+echo AC_OUTPUT >> configure.ac
+
+# not all shells like 'export var=value'...
+TAR_OPTIONS='--numeric-owner --test-tar-opt'
+export TAR_OPTIONS
+
+UNTAR_OPTIONS='--numeric-owner --test-untar-opt'
+export UNTAR_OPTIONS
+
+: > Makefile.am
+
+$ACLOCAL
+$AUTOCONF
+$AUTOMAKE
+./configure
+
+# debug:
+#grep am__tar Makefile
+#grep am__untar Makefile
+
+grep am__tar Makefile | grep '$${TAR_OPTIONS}' || exit 1
+grep am__untar Makefile | grep '$${UNTAR_OPTIONS}' || exit 2
+
+# 'tar' is expected to fail with invalid options, hence this:
+($MAKE dist-gzip 2>&1 || true) | grep test-tar-opt || exit 3
+($MAKE distcheck 2>&1 || true) | grep test-untar-opt || exit 4
+
+:
-- 
2.35.1