meson: add feature flag for nspawn build (#36876)

Other tools have it, nspawn doesn't, add one

.github/workflows/unit_tests.sh

@@ -107,7 +107,7 @@ for phase in "${PHASES[@]}"; do
                 MESON_ARGS+=(-Db_lundef=false -Dfuzz-tests=true)
 
                 if [[ "$phase" == "RUN_CLANG_ASAN_UBSAN_NO_DEPS" ]]; then
-                    MESON_ARGS+=(--auto-features=disabled)
+                    MESON_ARGS+=(--auto-features=disabled -Dnspawn=enabled)
                 fi
             fi
             MESON_ARGS+=(--fatal-meson-warnings)

man/rules/meson.build

@@ -1027,7 +1027,7 @@ manpages = [
   'ENABLE_NETWORKD'],
  ['systemd-networkd.service', '8', ['systemd-networkd'], 'ENABLE_NETWORKD'],
  ['systemd-notify', '1', [], ''],
- ['systemd-nspawn', '1', [], ''],
+ ['systemd-nspawn', '1', [], 'ENABLE_NSPAWN'],
  ['systemd-nsresourced.service',
   '8',
   ['systemd-nsresourced'],
@@ -1192,7 +1192,7 @@ manpages = [
  ['systemd.net-naming-scheme', '7', [], ''],
  ['systemd.netdev', '5', [], 'ENABLE_NETWORKD'],
  ['systemd.network', '5', [], 'ENABLE_NETWORKD'],
- ['systemd.nspawn', '5', [], ''],
+ ['systemd.nspawn', '5', [], 'ENABLE_NSPAWN'],
  ['systemd.offline-updates', '7', [], ''],
  ['systemd.path', '5', [], ''],
  ['systemd.pcrlock', '5', ['systemd.pcrlock.d'], ''],

man/systemd-nspawn.xml

@@ -6,7 +6,7 @@
 ]>
 <!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
 
-<refentry id="systemd-nspawn"
+<refentry id="systemd-nspawn" conditional="ENABLE_NSPAWN"
     xmlns:xi="http://www.w3.org/2001/XInclude">
 
   <refentryinfo>

meson.build

@@ -1610,6 +1610,9 @@ conf.set10('ENABLE_REMOTE', have)
 feature = get_option('vmspawn').disable_auto_if(conf.get('BUILD_MODE_DEVELOPER') == 0)
 conf.set10('ENABLE_VMSPAWN', feature.allowed())
 
+feature = get_option('nspawn')
+conf.set10('ENABLE_NSPAWN', feature.allowed())
+
 conf.set10('DEFAULT_MOUNTFSD_TRUSTED_DIRECTORIES', get_option('default-mountfsd-trusted-directories'))
 
 foreach term : ['analyze',
@@ -3046,6 +3049,7 @@ foreach tuple : [
         ['machined'],
         ['mountfsd'],
         ['networkd'],
+        ['nspawn'],
         ['nsresourced'],
         ['nss-myhostname'],
         ['nss-mymachines'],

meson_options.txt

@@ -178,6 +178,8 @@ option('rfkill', type : 'boolean',
        description : 'support for the rfkill tools')
 option('xdg-autostart', type : 'boolean',
        description : 'install the xdg-autostart-generator and unit')
+option('nspawn', type : 'feature',
+       description : 'build and install systemd-nspawn')
 option('man', type : 'feature', deprecated : { 'true' : 'enabled', 'false' : 'disabled' },
        value : 'disabled',
        description : 'build and install man pages')

shell-completion/bash/meson.build

@@ -28,7 +28,7 @@ items = [['busctl',              ''],
          ['systemd-delta',       ''],
          ['systemd-detect-virt', ''],
          ['systemd-id128',       ''],
-         ['systemd-nspawn',      ''],
+         ['systemd-nspawn',      'ENABLE_NSPAWN'],
          ['systemd-path',        ''],
          ['systemd-run',         ''],
          ['systemd-vpick',       ''],

src/nspawn/meson.build

@@ -1,5 +1,9 @@
 # SPDX-License-Identifier: LGPL-2.1-or-later
 
+if conf.get('ENABLE_NSPAWN') != 1
+        subdir_done()
+endif
+
 libnspawn_core_sources = files(
         'nspawn-bind-user.c',
         'nspawn-cgroup.c',
@@ -58,14 +62,18 @@ executables += [
         },
         nspawn_test_template + {
                 'sources' : files('test-nspawn-tables.c'),
+                'conditions' : ['ENABLE_NSPAWN'],
         },
         nspawn_test_template + {
                 'sources' : files('test-nspawn-util.c'),
+                'conditions' : ['ENABLE_NSPAWN'],
         },
         nspawn_fuzz_template + {
                 'sources' : files('fuzz-nspawn-settings.c'),
+                'conditions' : ['ENABLE_NSPAWN'],
         },
         nspawn_fuzz_template + {
                 'sources' : files('fuzz-nspawn-oci.c'),
+                'conditions' : ['ENABLE_NSPAWN'],
         },
 ]

test/fuzz/meson.build

@@ -60,7 +60,7 @@ sanitize_address_undefined = custom_target(
                    'fuzzers',
                    ' '.join(fuzz_c_args + '-DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION'),
                    ' '.join(fuzz_cpp_args + '-DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION'),
-                   '-Dfuzz-tests=true -Db_lundef=false -Db_sanitize=address,undefined --optimization=@0@ @1@ --auto-features=@2@'.format(
+                   '-Dfuzz-tests=true -Db_lundef=false -Db_sanitize=address,undefined -Dnspawn=enabled --optimization=@0@ @1@ --auto-features=@2@'.format(
                            get_option('optimization'),
                            get_option('werror') ? '--werror' : '',
                            sanitize_auto_features

test/meson.build

@@ -359,11 +359,9 @@ if install_tests
                                exclude_files : '.gitattributes',
                                install_dir : testdata_dir)
         endif
-        if conf.get('ENABLE_RESOLVE') == 1
-                install_subdir('test-resolve',
-                               exclude_files : '.gitattributes',
-                               install_dir : testdata_dir)
-        endif
+        install_subdir('test-resolve',
+                       exclude_files : '.gitattributes',
+                       install_dir : testdata_dir)
 
         # The unit tests implemented as shell scripts expect to find testdata/
         # in the directory where they are stored.

test/units/TEST-13-NSPAWN.sh

@@ -10,6 +10,11 @@ if [[ "$FSTYPE" == "fuseblk" ]]; then
     exit 77
 fi
 
+if ! command -v systemd-nspawn >/dev/null; then
+    echo "no systemd-nspawn" >/skipped
+    exit 77
+fi
+
 # shellcheck source=test/units/test-control.sh
 . "$(dirname "$0")"/test-control.sh
 

units/meson.build

@@ -514,7 +514,10 @@ units = [
           'file' : 'systemd-networkd.socket',
           'conditions' : ['ENABLE_NETWORKD'],
         },
-        { 'file' : 'systemd-nspawn@.service.in' },
+        {
+          'file' : 'systemd-nspawn@.service.in',
+          'conditions' : ['ENABLE_NSPAWN'],
+        },
         {
           'file' : 'systemd-vmspawn@.service.in',
           'conditions' : ['ENABLE_VMSPAWN'],