build: support building all tools in a single binary

Add the --enable-single-binary option to the configure file.
When enabled, this option builds a single binary file containing
the selected tools.  Which tool gets executed depends on the value
of argv[0] which can be set implicitly through symlinks to the
single program.

This setup reduces significantly the size of a complete coreutils
install, since code from lib/libcoreutils.a is not duplicated in
every one of the more than 100 binaries.  Runtime overhead is
increased due to more dynamic libraries being loaded, and extra
initialization being performed for all utils.  Also initially
a larger binary is loaded from storage, though this is usually
alleviated due to caching and lazy mmaping of unused blocks,
and in fact the single binary should have better caching
characteristics.

Comparing the size of the individual versus single binary on x86_64:
  $ cd src
  $ size coreutils
  $ size -t $(../build-aux/gen-lists-of-programs.sh --list-progs |
              grep -Ev '(coreutils|libstdbuf)') | tail -n1
     text    data     bss     dec     hex filename
  1097416    5388   88432 1191236  122d44 src/coreutils
  4901010  124964  163768 5189742  4f306e (TOTALS)

Storage requirements are reduced similarly:
  $ cd src
  $ du -h coreutils
  $ du -ch $(../build-aux/gen-lists-of-programs.sh --list-progs |
             grep -Ev '(coreutils|libstdbuf)') | tail -n1
  1.2M    coreutils
  5.3M    total

When installing, the makefile will create either symlinks or
shebangs based on the --enable-single-binary setting, for
each configured tool. In this way, all the tools are still
callable individually, but they are all implemented by the same
"coreutils" binary installed on the same directory.

* .gitignore: Add new generated files.
* Makefile.am: New rules to generate build-aux/gen-single-binary.sh
  and install symlinks.
* NEWS: Mention the new feature.
* README: Add "coreutils" to the list of utils.
* bootstrap.conf: Regenerate src/single-binary.mk
* build-aux/gen-lists-of-programs.sh: New --list-progs option.
* build-aux/gen-single-binary.sh: Regenerate
* configure.ac: New --enable-single-binary option and other variables.
Disallow --enable-single-binary=symlinks with --program-prefix et. al.
* man/coreutils.x: Manpage hook.
* man/local.mk: Add manpage hook and fix dependencies.
* src/coreutils.c: Multicall implementation.
* src/local.mk: New rules for the single binary option.
* tests/local.mk: Add $single_binary_progs to support
require_built_() from init.cfg
* tests/misc/env.sh: Avoid the use of symlink to echo.
* tests/misc/help-version.sh: Add exception for coreutils.
* tests/install/basic-1.sh: Really avoid using ginstall strip
functionality if there is an issue with the independent strip command.
* src/kill.c: Changes to call exit() in main.
* src/readlink.c: Likewise.
* src/shuf.c: Likewise.
* src/timeout.c: Likewise.
* src/truncate.c: Likewise.

5 files changed, 56 insertions, 10 deletions

diff --git a/tests/install/basic-1.sh b/tests/install/basic-1.sh
index 9835d463e..0c0d1de86 100755
--- a/tests/install/basic-1.sh
+++ b/tests/install/basic-1.sh
@@ -46,13 +46,17 @@ is not readable, so skipping the remaining tests in this file."
 cp "$just_built_dd" . || fail=1
 cp $dd $dd2 || fail=1
 
-strip $dd2 \
-  || warn_ "WARNING!!! Your strip command doesn't seem to work,
+strip=-s
+if ! strip $dd2; then
+  ! test -e $abs_top_builddir/src/coreutils \
+    && warn_ "WARNING!!! Your strip command doesn't seem to work,
 so skipping the test of install's --strip option."
+  strip=
+fi
 
 # This test would fail with 3.16s when using versions of strip that
 # don't work on read-only files (the one from binutils works fine).
-ginstall -s -c -m 555 $dd $dir || fail=1
+ginstall $strip -c -m 555 $dd $dir || fail=1
 # Make sure the source file is still around.
 test -f $dd || fail=1
 
diff --git a/tests/local.mk b/tests/local.mk
index 86050dc79..e0f1f84ee 100644
--- a/tests/local.mk
+++ b/tests/local.mk
@@ -65,7 +65,7 @@ TESTS_ENVIRONMENT =				\
   abs_top_builddir='$(abs_top_builddir)'	\
   abs_top_srcdir='$(abs_top_srcdir)'		\
   abs_srcdir='$(abs_srcdir)'			\
-  built_programs='$(built_programs)'		\
+  built_programs='$(built_programs) $(single_binary_progs)' \
   host_os=$(host_os)				\
   host_triplet='$(host_triplet)'		\
   srcdir='$(srcdir)'				\
@@ -249,6 +249,7 @@ all_tests =					\
   tests/pr/pr-tests.pl				\
   tests/misc/pwd-option.sh			\
   tests/misc/chcon-fail.sh			\
+  tests/misc/coreutils.sh			\
   tests/misc/cut.pl				\
   tests/misc/cut-huge-range.sh			\
   tests/misc/wc.pl				\
diff --git a/tests/misc/coreutils.sh b/tests/misc/coreutils.sh
new file mode 100755
index 000000000..a22bc9f64
--- /dev/null
+++ b/tests/misc/coreutils.sh
@@ -0,0 +1,36 @@
+#!/bin/sh
+# Verify behavior of separate coreutils multicall binary
+
+# Copyright (C) 2014 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 3 of the License, 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/>.
+
+
+. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
+print_ver_ coreutils
+
+test -s "$abs_top_builddir/src/coreutils.h" \
+ || skip_ "multicall binary is disabled"
+
+# Yes outputs all its params so is good to verify argv manipulations
+echo 'y' > exp
+coreutils --coreutils-prog=yes | head -n10 | uniq > out
+compare exp out || fail=1
+
+# Ensure if incorrect program passed, we diagnose
+echo "coreutils: unknown program 'blah'" > exp
+coreutils --coreutils-prog='blah' --help 2>err && fail=1
+compare exp err || fail=1
+
+Exit $fail
diff --git a/tests/misc/env.sh b/tests/misc/env.sh
index c4b97377a..883c58f54 100755
--- a/tests/misc/env.sh
+++ b/tests/misc/env.sh
@@ -20,6 +20,10 @@
 . "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
 print_ver_ env
 
+# A simple shebang program to call "echo" from symlinks like "./-u" or "./--".
+echo "#!$abs_top_builddir/src/echo simple_echo" > simple_echo \
+  || framework_failure_
+chmod a+x simple_echo || framework_failure_
 
 # Verify clearing the environment
 a=1
@@ -105,9 +109,10 @@ export PATH
 # Use -- to end options (but not variable assignments).
 # On some systems, execve("-i") invokes a shebang script ./-i on PATH as
 # '/bin/sh -i', rather than '/bin/sh -- -i', which doesn't do what we want.
-# Avoid the issue by using an executable rather than a script.
+# Avoid the issue by using a shebang to 'echo' passing a second parameter
+# before the '-i'. See the definition of simple_echo before.
 # Test -u, rather than -i, to minimize PATH problems.
-ln -s "$abs_top_builddir/src/echo" ./-u || framework_failure_
+ln -s "simple_echo" ./-u || framework_failure_
 case $(env -u echo echo good) in
   good) ;;
   *) fail=1 ;;
@@ -117,16 +122,16 @@ case $(env -u echo -- echo good) in
   *) fail=1 ;;
 esac
 case $(env -- -u pass) in
-  pass) ;;
+  *pass) ;;
   *) fail=1 ;;
 esac
 
 # After options have ended, the first argument not containing = is a program.
 env a=b -- true
 test $? = 127 || fail=1
-ln -s "$abs_top_builddir/src/echo" ./-- || framework_failure_
+ln -s "simple_echo" ./-- || framework_failure_
 case $(env a=b -- true || echo fail) in
-  true) ;;
+  *true) ;;
   *) fail=1 ;;
 esac
 
diff --git a/tests/misc/help-version.sh b/tests/misc/help-version.sh
index b4939f7af..0598557f2 100755
--- a/tests/misc/help-version.sh
+++ b/tests/misc/help-version.sh
@@ -239,7 +239,7 @@ parted_setup () { args="-s $tmp_in mklabel gpt"
 # something more than --help or --version.
 for i in $built_programs; do
   # Skip these.
-  case $i in chroot|stty|tty|false|chcon|runcon) continue;; esac
+  case $i in chroot|stty|tty|false|chcon|runcon|coreutils) continue;; esac
 
   rm -rf $tmp_in $tmp_in2 $tmp_dir $tmp_out $bigZ_in $zin $zin2
   echo z |gzip > $zin