[PATCH 4/4] missing: don't try to re-run tar with a munged command line

[Stefano Lattarini]

* lib/missing: If the default `tar' program fails with the given
arguments, and GNU tar is not available, don't try to re-run the
default `tar' with a munged command line (e.g., ditching possibly
unportable options), as that could be subtly alter the intended
semantics (and maybe even create a somewhat corrupted tarball).
Also, it's worth noting that the main purpose of the `missing'
script is to allow a non-developer to build the package in the
face of slightly-skewed timestamps, not to provide wrappers for
all the maintainer tools -- so we don't have to try too hard
when `missing' is just called to wrap `tar'.
* tests/missing-tar.test: New test.
* tests/Makefile.am (TESTS): Add it.
---
 ChangeLog              |   16 +++++
 lib/missing            |   18 +-----
 tests/Makefile.am      |    1 +
 tests/Makefile.in      |    1 +
 tests/missing-tar.test |  153 ++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 172 insertions(+), 17 deletions(-)
 create mode 100755 tests/missing-tar.test

diff --git a/ChangeLog b/ChangeLog
index 06f3abd..164d9bb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,21 @@
 2011-10-30  Stefano Lattarini  <address@hidden>
 
+       missing: don't try to re-run tar with a munged command line
+       * lib/missing: If the default `tar' program fails with the given
+       arguments, and GNU tar is not available, don't try to re-run the
+       default `tar' with a munged command line (e.g., ditching possibly
+       unportable options), as that could be subtly alter the intended
+       semantics (and maybe even create a somewhat corrupted tarball).
+       Also, it's worth noting that the main purpose of the `missing'
+       script is to allow a non-developer to build the package in the
+       face of slightly-skewed timestamps, not to provide wrappers for
+       all the maintainer tools -- so we don't have to try too hard
+       when `missing' is just called to wrap `tar'.
+       * tests/missing-tar.test: New test.
+       * tests/Makefile.am (TESTS): Add it.
+
+2011-10-30  Stefano Lattarini  <address@hidden>
+
        missing: inform the user if GNU tar is called
        * lib/missing: If the code trying to run GNU tar is reached, it
        means that the previous attempt to run the default tar program
diff --git a/lib/missing b/lib/missing
index 34c3239..7f4950e 100755
--- a/lib/missing
+++ b/lib/missing
@@ -1,7 +1,7 @@
 #! /bin/sh
 # Common stub for a few missing GNU programs while installing.
 
-scriptversion=2011-10-30.08; # UTC
+scriptversion=2011-10-30.10; # UTC
 
 # Copyright (C) 1996, 1997, 1999, 2000, 2002, 2003, 2004, 2005, 2006,
 # 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
@@ -329,22 +329,6 @@ WARNING: I can't seem to be able to run \`tar' with the 
given arguments.
          Trying to use GNU tar (\"$cmd\") instead ..."
       exec $cmd "$@"
     done
-    firstarg=$1
-    if shift; then
-       case $firstarg in
-       *o*)
-           firstarg=`echo "$firstarg" | sed s/o//`
-           tar "$firstarg" "$@" && exit 0
-           ;;
-       esac
-       case $firstarg in
-       *h*)
-           firstarg=`echo "$firstarg" | sed s/h//`
-           tar "$firstarg" "$@" && exit 0
-           ;;
-       esac
-    fi
-
     echo 1>&2 "\
 WARNING: I can't seem to be able to run \`tar' with the given arguments.
          You may want to install GNU tar or Free paxutils, or check the
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 301a2b9..7bc18b4 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -574,6 +574,7 @@ missing3.test \
 missing4.test \
 missing5.test \
 missing6.test \
+missing-tar.test \
 mkinstall.test \
 mkinst2.test \
 mkinst3.test \
diff --git a/tests/Makefile.in b/tests/Makefile.in
index 0eece13..742e7ef 100644
--- a/tests/Makefile.in
+++ b/tests/Makefile.in
@@ -858,6 +858,7 @@ missing3.test \
 missing4.test \
 missing5.test \
 missing6.test \
+missing-tar.test \
 mkinstall.test \
 mkinst2.test \
 mkinst3.test \
diff --git a/tests/missing-tar.test b/tests/missing-tar.test
new file mode 100755
index 0000000..e90e03a
--- /dev/null
+++ b/tests/missing-tar.test
@@ -0,0 +1,153 @@
+#! /bin/sh
+# Copyright (C) 2011 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 <http://www.gnu.org/licenses/>.
+
+# Test how the `missing' script wraps the`tar' program .
+# FIXME: we should also try to run the `missing' script with the
+#        $CONFIG_SHELL ...
+
+. ./defs || Exit 1
+
+set -e
+
+# FIXME: make this working with "installcheck" too ...
+cp "$testsrcdir"/../lib/missing . \
+  || fatal_ "failed to fetch auxiliary script \`missing'"
+
+old_PATH=$PATH; export old_PATH
+new_PATH=`pwd`/bin$PATH_SEPARATOR$PATH
+mkdir bin
+
+cat > data.txt <<'END'
+To be, or not to be: that is the question:
+Whether 'tis nobler in the mind to suffer
+...
+END
+
+cat > nonesuch <<'END'
+#!/bin/sh
+exit 127
+END
+chmod a+x nonesuch
+
+# Simple runs.
+for nullify_gnu in yes no; do
+  case $nullify_gnu in
+    yes)
+      cp nonesuch bin/gtar
+      cp nonesuch bin/gnutar
+      PATH=$new_PATH; export PATH;
+      mkdir simple-nognu
+      cd simple-nognu
+      ;;
+    no)
+      mkdir simple-dflt
+      cd simple-dflt
+      ;;
+    *)
+      Exit 99 # Can't happen.
+      ;;
+  esac
+  cp ../data.txt foobar.txt
+  ../missing --run tar cvf mu.tar foobar.txt
+  rm -f foobar.txt
+  test -f mu.tar
+  ../missing --run tar tf mu.tar >output 2>&1 || { cat output; Exit 1; }
+  cat output
+  $FGREP 'foobar.txt' output
+  test ! -f foobar.txt
+  ../missing --run tar xvf mu.tar
+  diff ../data.txt foobar.txt
+  PATH=$old_PATH; export PATH;
+  cd ..
+done
+
+rm -f bin/*
+
+# Helper scripts and functions for next tests.
+
+cat > fake-gnu-tar <<'END'
+#!/bin/sh
+case " $* " in *\ --version\ *) echo fake GNU tar; exit $?;; esac
+PATH=$old_PATH; export PATH
+exec tar "$@"
+END
+chmod a+x fake-gnu-tar
+
+cat > failing-tar <<'END'
+#!/bin/sh
+echo "Error message from tar passed through" >&2
+exit 1
+END
+chmod a+x failing-tar
+
+grep_tar_failed ()
+{
+  grep "WARNING:.* can't.* run \`tar' with .*given arguments" $*
+}
+
+# The `tar' program does not work with the given options, but we have
+# gtar or gnutar.
+cp failing-tar bin/tar
+for pfx in g gnu; do
+  case $pfx in g) othpfx=gnu;; gnu) othpfx=g;; *) Exit 99;; esac
+  cp nonesuch bin/${othpfx}tar
+  if ${pfx}tar --version | grep GNU; then :; else
+    cp fake-gnu-tar bin/${pfx}tar
+  fi
+  tarball=foo-$pfx.tar
+  PATH=$new_PATH; export PATH
+  ./missing --run tar cvf $tarball ./data.txt 2>stderr \
+    || { cat stderr >&2; Exit 1; }
+  cat stderr >&2
+  PATH=$old_PATH; export PATH
+  test -f $tarball
+  grep_tar_failed stderr
+  grep "Error message from tar passed through" stderr
+  grep "[Tt]rying to use GNU tar.*${pfx}tar" stderr
+  grep "${othpfx}tar" stderr && Exit 1
+  : # For shells with broken 'set -e'
+done
+
+rm -f bin/*
+
+# The `tar' program does not work with the given options, and we don't
+# have neither gtar nor gnutar.
+cp failing-tar bin/tar
+cp nonesuch bin/gtar
+cp nonesuch bin/gnutar
+PATH=$new_PATH; export PATH
+./missing --run tar cvf foo.tar ./data.txt 2>stderr \
+  && { cat stderr >&2; Exit 1; }
+cat stderr >&2
+PATH=$old_PATH; export PATH
+test ! -f foo.tar
+grep_tar_failed stderr
+grep "Error message from tar passed through" stderr
+grep "[iI]nstall GNU tar or Free [pP]axutils" stderr
+$EGREP "(g|gnu)tar" stderr && Exit 1
+
+rm -f bin/*
+
+# We try to use an option that causes any `tar' program (GNU or non-GNU) to.
+sh -x ./missing --run tar --bad-unknonw-option cvf foo.tar ./data.txt 2>stderr 
\
+  && { cat stderr >&2; Exit 1; }
+cat stderr >&2
+test ! -f foo.tar
+grep_tar_failed stderr
+grep "bad-unknonw-option" stderr
+test `$EGREP -c "[Tt]rying to use GNU tar.*(g|gnu)tar" stderr` -eq 1
+
+:
-- 
1.7.2.3