systemd: support disabling cloud-init via file or kernel cmdline

This adds a systemd generator for a 'cloud-init.target'.  That target will
be WantedBy multi-user.target in the default case.  If there is a file
/etc/cloud/cloud-init.disabled or the kernel command line contains
'cloud-init=disabled' then cloud-init will not affect boot at all.

There are some packages/debian changes to affect this:
 * postinst, preinst: these are necessary to remove some
   old target files for multi-user.target (LP: #1552999)
 * changes to include these files in the debian source package.
 * rules.in: supports DEB_BUILD_OPTIONS=nocheck to not run check

setup.py: mostly changes to support installing the generator
          but also pep8 fixes along the way

systemd/*: make each of the services 'WantedBy=cloud-init.target'
           rather than being wanted by multi-user.target

11 files changed, 230 insertions, 40 deletions

diff --git a/packages/bddeb b/packages/bddeb
index c4efe264..c141b1ab 100755
--- a/packages/bddeb
+++ b/packages/bddeb
@@ -1,5 +1,6 @@
 #!/usr/bin/env python3
 
+import glob
 import os
 import shutil
 import sys
@@ -105,11 +106,11 @@ def write_debian_folder(root, version, revno, pkgmap,
                              util.abs_join(deb_dir, 'rules'),
                              params={'python': python, 'pyver': pyver})
 
-    # Just copy the following directly
-    for base_fn in ['dirs', 'copyright', 'compat']:
-        shutil.copy(util.abs_join(find_root(),
-                                  'packages', 'debian', base_fn),
-                    util.abs_join(deb_dir, base_fn))
+    # Just copy any other files directly (including .in)
+    pdeb_d = util.abs_join(find_root(), 'packages', 'debian')
+    for f in [os.path.join(pdeb_d, f) for f in os.listdir(pdeb_d)]:
+        if os.path.isfile(f):
+            shutil.copy(f, util.abs_join(deb_dir, os.path.basename(f)))
 
 
 def main():
diff --git a/packages/debian/cloud-init.postinst b/packages/debian/cloud-init.postinst
new file mode 100644
index 00000000..cdd0466d
--- /dev/null
+++ b/packages/debian/cloud-init.postinst
@@ -0,0 +1,16 @@
+#!/bin/sh
+cleanup_lp1552999() {
+    local oldver="$1" last_bad_ver="0.7.7~bzr1178"
+    dpkg --compare-versions "$oldver" le "$last_bad_ver" || return 0
+    local edir="/etc/systemd/system/multi-user.target.wants"
+    rm -f "$edir/cloud-config.service" "$edir/cloud-final.service" \
+        "$edir/cloud-init-local.service" "$edir/cloud-init.service"
+}
+
+
+#DEBHELPER#
+
+if [ "$1" = "configure" ]; then
+   oldver="$2"
+   cleanup_lp1552999 "$oldver"
+fi
diff --git a/packages/debian/cloud-init.preinst b/packages/debian/cloud-init.preinst
new file mode 100644
index 00000000..3c2af06d
--- /dev/null
+++ b/packages/debian/cloud-init.preinst
@@ -0,0 +1,20 @@
+#!/bin/sh
+# vi: ts=4 expandtab
+
+cleanup_lp1552999() {
+    local oldver="$1" last_bad_ver="0.7.7~bzr1178"
+    dpkg --compare-versions "$oldver" le "$last_bad_ver" || return 0
+    local hdir="/var/lib/systemd/deb-systemd-helper-enabled"
+    hdir="$hdir/multi-user.target.wants" 
+    local edir="/etc/systemd/system/multi-user.target.wants"
+    rm -f "$hdir/cloud-config.service" "$hdir/cloud-final.service" \
+        "$hdir/cloud-init-local.service" "$hdir/cloud-init.service"
+}
+
+
+if [ "$1" = "upgrade" ]; then
+   oldver="$2"
+   cleanup_lp1552999 "$oldver"
+fi
+
+#DEBHELPER#
diff --git a/packages/debian/rules.in b/packages/debian/rules.in
index 66e80946..5420949c 100755
--- a/packages/debian/rules.in
+++ b/packages/debian/rules.in
@@ -13,7 +13,11 @@ override_dh_install:
 	cp tools/21-cloudinit.conf debian/cloud-init/etc/rsyslog.d/21-cloudinit.conf
 
 override_dh_auto_test:
+ifeq (,$(findstring nocheck,$(DEB_BUILD_OPTIONS)))
 	http_proxy= make check
+else
+	@echo check disabled by DEB_BUILD_OPTIONS=$(DEB_BUILD_OPTIONS)
+endif
 
 override_dh_systemd_start:
 	dh_systemd_start --no-restart-on-upgrade --no-start
diff --git a/setup.py b/setup.py
index 5f61681b..0b261dfe 100755
--- a/setup.py
+++ b/setup.py
@@ -45,39 +45,50 @@ def tiny_p(cmd, capture=True):
         stdout = None
         stderr = None
     sp = subprocess.Popen(cmd, stdout=stdout,
-                    stderr=stderr, stdin=None,
-                    universal_newlines=True)
+                          stderr=stderr, stdin=None,
+                          universal_newlines=True)
     (out, err) = sp.communicate()
     ret = sp.returncode
     if ret not in [0]:
-        raise RuntimeError("Failed running %s [rc=%s] (%s, %s)"
-                            % (cmd, ret, out, err))
+        raise RuntimeError("Failed running %s [rc=%s] (%s, %s)" %
+                           (cmd, ret, out, err))
     return (out, err)
 
 
-def systemd_unitdir():
-    cmd = ['pkg-config', '--variable=systemdsystemunitdir', 'systemd']
+def pkg_config_read(library, var):
+    fallbacks = {
+       'systemd': {
+           'systemdsystemunitdir': '/lib/systemd/system',
+           'systemdsystemgeneratordir': '/lib/systemd/system-generators',
+       }
+    }
+    cmd = ['pkg-config', '--variable=%s' % var, library]
     try:
         (path, err) = tiny_p(cmd)
     except:
-        return '/lib/systemd/system'
+        return fallbacks[library][var]
     return str(path).strip()
 
+
 INITSYS_FILES = {
     'sysvinit': [f for f in glob('sysvinit/redhat/*') if is_f(f)],
     'sysvinit_freebsd': [f for f in glob('sysvinit/freebsd/*') if is_f(f)],
     'sysvinit_deb': [f for f in glob('sysvinit/debian/*') if is_f(f)],
-    'systemd': [f for f in glob('systemd/*') if is_f(f)],
+    'systemd': [f for f in (glob('systemd/*.service') +
+                            glob('systemd/*.target')) if is_f(f)],
+    'systemd.generators': [f for f in glob('systemd/*-generator') if is_f(f)],
     'upstart': [f for f in glob('upstart/*') if is_f(f)],
 }
 INITSYS_ROOTS = {
     'sysvinit': '/etc/rc.d/init.d',
     'sysvinit_freebsd': '/usr/local/etc/rc.d',
     'sysvinit_deb': '/etc/init.d',
-    'systemd': systemd_unitdir(),
+    'systemd': pkg_config_read('systemd', 'systemdsystemunitdir'),
+    'systemd.generators': pkg_config_read('systemd',
+                                          'systemdsystemgeneratordir'),
     'upstart': '/etc/init/',
 }
-INITSYS_TYPES = sorted(list(INITSYS_ROOTS.keys()))
+INITSYS_TYPES = sorted([f.partition(".")[0] for f in INITSYS_ROOTS.keys()])
 
 # Install everything in the right location and take care of Linux (default) and
 # FreeBSD systems.
@@ -122,9 +133,8 @@ class InitsysInstallData(install):
     user_options = install.user_options + [
         # This will magically show up in member variable 'init_sys'
         ('init-system=', None,
-            ('init system(s) to configure (%s) [default: None]') %
-                (", ".join(INITSYS_TYPES))
-        ),
+         ('init system(s) to configure (%s) [default: None]' %
+          (", ".join(INITSYS_TYPES)))),
     ]
 
     def initialize_options(self):
@@ -138,7 +148,8 @@ class InitsysInstallData(install):
             self.init_system = self.init_system.split(",")
 
         if len(self.init_system) == 0:
-            raise DistutilsArgError(("You must specify one of (%s) when"
+            raise DistutilsArgError(
+                ("You must specify one of (%s) when"
                  " specifying init system(s)!") % (", ".join(INITSYS_TYPES)))
 
         bad = [f for f in self.init_system if f not in INITSYS_TYPES]
@@ -147,8 +158,12 @@ class InitsysInstallData(install):
                 "Invalid --init-system: %s" % (','.join(bad)))
 
         for system in self.init_system:
-            self.distribution.data_files.append(
-                (INITSYS_ROOTS[system], INITSYS_FILES[system]))
+            # add data files for anything that starts with '<system>.'
+            datakeys = [k for k in INITSYS_ROOTS
+                        if k.partition(".")[0] == system]
+            for k in datakeys:
+                self.distribution.data_files.append(
+                    (INITSYS_ROOTS[k], INITSYS_FILES[k]))
         # Force that command to reinitalize (with new file list)
         self.distribution.reinitialize_command('install_data', True)
 
@@ -182,18 +197,18 @@ if sys.version_info < (3,):
     requirements.append('cheetah')
 
 
-setuptools.setup(name='cloud-init',
-      version=get_version(),
-      description='EC2 initialisation magic',
-      author='Scott Moser',
-      author_email='scott.moser@canonical.com',
-      url='http://launchpad.net/cloud-init/',
-      packages=setuptools.find_packages(exclude=['tests']),
-      scripts=['bin/cloud-init',
-               'tools/cloud-init-per',
-               ],
-      license='GPLv3',
-      data_files=data_files,
-      install_requires=requirements,
-      cmdclass=cmdclass,
-      )
+setuptools.setup(
+    name='cloud-init',
+    version=get_version(),
+    description='EC2 initialisation magic',
+    author='Scott Moser',
+    author_email='scott.moser@canonical.com',
+    url='http://launchpad.net/cloud-init/',
+    packages=setuptools.find_packages(exclude=['tests']),
+    scripts=['bin/cloud-init',
+             'tools/cloud-init-per'],
+    license='GPLv3',
+    data_files=data_files,
+    install_requires=requirements,
+    cmdclass=cmdclass,
+    )
diff --git a/systemd/cloud-config.service b/systemd/cloud-config.service
index f9f1996e..45d2a63b 100644
--- a/systemd/cloud-config.service
+++ b/systemd/cloud-config.service
@@ -13,4 +13,4 @@ TimeoutSec=0
 StandardOutput=journal+console
 
 [Install]
-WantedBy=multi-user.target
+WantedBy=cloud-init.target
diff --git a/systemd/cloud-final.service b/systemd/cloud-final.service
index bcbdd36f..bfb08d4a 100644
--- a/systemd/cloud-final.service
+++ b/systemd/cloud-final.service
@@ -14,4 +14,4 @@ KillMode=process
 StandardOutput=journal+console
 
 [Install]
-WantedBy=multi-user.target
+WantedBy=cloud-init.target
diff --git a/systemd/cloud-init-generator b/systemd/cloud-init-generator
new file mode 100755
index 00000000..9d1e22f0
--- /dev/null
+++ b/systemd/cloud-init-generator
@@ -0,0 +1,128 @@
+#!/bin/sh
+set -f
+
+LOG=""
+DEBUG_LEVEL=1
+LOG_D="/run"
+ENABLE="enabled"
+DISABLE="disabled"
+CLOUD_SYSTEM_TARGET="/lib/systemd/system/cloud-init.target"
+CLOUD_TARGET_NAME="cloud-init.target"
+# lxc sets 'container', but lets make that explicitly a global
+CONTAINER="${container}"
+
+debug() {
+    local lvl="$1"
+    shift
+    [ "$lvl" -gt "$DEBUG_LEVEL" ] && return
+    if [ -z "$LOG" ]; then
+        local log="$LOG_D/${0##*/}.log"
+        { : > "$log"; } >/dev/null 2>&1 && LOG="$log" ||
+            LOG="/dev/kmsg"
+    fi
+    echo "$@" >> "$LOG"
+}
+
+etc_file() {
+    local pprefix="${1:-/etc/cloud/cloud-init.}"
+    _RET="unset"
+    [ -f "${pprefix}$ENABLE" ] && _RET="$ENABLE" && return 0
+    [ -f "${pprefix}$DISABLE" ] && _RET="$DISABLE" && return 0
+    return 0
+}
+
+read_proc_cmdline() {
+    if [ "$CONTAINER" = "lxc" ]; then
+        _RET_MSG="ignored: \$container=$CONTAINER"
+        _RET=""
+        return 0
+    fi
+
+    if systemd-detect-virt --container --quiet; then
+        _RET_MSG="ignored: detect-virt is container"
+        _RET=""
+        return 0
+    fi
+
+    _RET_MSG="/proc/cmdline"
+    read _RET < /proc/cmdline
+}
+
+kernel_cmdline() {
+    local cmdline="" tok=""
+    if [ -n "${KERNEL_CMDLINE+x}" ]; then
+        # use KERNEL_CMDLINE if present in environment even if empty
+        cmdline=${KERNEL_CMDLINE}
+        debug 1 "kernel command line from env KERNEL_CMDLINE: $cmdline"
+    elif read_proc_cmdline; then
+        read_proc_cmdline && cmdline="$_RET"
+        debug 1 "kernel command line ($_RET_MSG): $cmdline"
+    fi
+    _RET="unset"
+    cmdline=" $cmdline "
+    tok=${cmdline##* cloud-init=}
+    [ "$tok" = "$cmdline" ] && _RET="unset"
+    tok=${tok%% *}
+    [ "$tok" = "$ENABLE" -o "$tok" = "$DISABLE" ] && _RET="$tok"
+    return 0
+}
+
+default() {
+    _RET="$ENABLE"
+}
+
+main() {
+    local normal_d="$1" early_d="$2" late_d="$3"
+    local target_name="multi-user.target" gen_d="$early_d"
+    local link_path="$gen_d/${target_name}.wants/${CLOUD_TARGET_NAME}"
+
+    debug 1 "$0 normal=$normal_d early=$early_d late=$late_d"
+    debug 2 "$0 $*"
+
+    local search result="error" ret=""
+    for search in kernel_cmdline etc_file default; do
+        if $search; then
+            debug 1 "$search found $_RET"
+            [ "$_RET" = "$ENABLE" -o "$_RET" = "$DISABLE" ] &&
+                result=$_RET && break
+        else
+            ret=$?
+            debug 0 "search $search returned $ret"
+        fi
+    done
+    
+    if [ "$result" = "$ENABLE" ]; then
+        if [ -e "$link_path" ]; then
+                debug 1 "already enabled: no change needed"
+        else
+            [ -d "${link_path%/*}" ] || mkdir -p "${link_path%/*}" ||
+                debug 0 "failed to make dir $link_path"
+            if ln -snf "$CLOUD_SYSTEM_TARGET" "$link_path"; then
+                debug 1 "enabled via $link_path -> $CLOUD_SYSTEM_TARGET"
+            else
+                ret=$?
+                debug 0 "[$ret] enable failed:" \
+                    "ln $CLOUD_SYSTEM_TARGET $link_path"
+            fi
+        fi
+    elif [ "$result" = "$DISABLE" ]; then
+        if [ -f "$link_path" ]; then
+            if rm -f "$link_path"; then
+                debug 1 "disabled. removed existing $link_path"
+            else
+                ret=$?
+                debug 0 "[$ret] disable failed, remove $link_path"
+            fi
+        else
+            debug 1 "already disabled: no change needed [no $link_path]"
+        fi
+    else
+        debug 0 "unexpected result '$result'"
+        ret=3
+    fi
+    return $ret
+}
+
+main "$@"
+
+# vi: ts=4 expandtab
diff --git a/systemd/cloud-init-local.service b/systemd/cloud-init-local.service
index a31985c6..73aa46f6 100644
--- a/systemd/cloud-init-local.service
+++ b/systemd/cloud-init-local.service
@@ -13,4 +13,4 @@ TimeoutSec=0
 StandardOutput=journal+console
 
 [Install]
-WantedBy=multi-user.target
+WantedBy=cloud-init.target
diff --git a/systemd/cloud-init.service b/systemd/cloud-init.service
index 48920283..1f656f7f 100644
--- a/systemd/cloud-init.service
+++ b/systemd/cloud-init.service
@@ -15,4 +15,4 @@ TimeoutSec=0
 StandardOutput=journal+console
 
 [Install]
-WantedBy=multi-user.target
+WantedBy=cloud-init.target
diff --git a/systemd/cloud-init.target b/systemd/cloud-init.target
new file mode 100644
index 00000000..a63babb0
--- /dev/null
+++ b/systemd/cloud-init.target
@@ -0,0 +1,6 @@
+# cloud-init target is enabled by cloud-init-generator
+# To disable it you can either:
+#  a.) boot with kernel cmdline of 'cloudinit=disabled'
+#  b.) touch a file /etc/cloud/cloud-init.disabled
+[Unit]
+Description=Cloud-init target