meson: generate m4 preprocessor from config.h (#8914)

meson.build

@@ -17,7 +17,7 @@ project('systemd', 'c',
 libsystemd_version = '0.22.0'
 libudev_version = '1.6.10'
 
-# We need the same data in three different formats, ugh!
+# We need the same data in two different formats, ugh!
 # Also, for hysterical reasons, we use different variable
 # names, sometimes. Not all variables are included in every
 # set. Ugh, ugh, ugh!
@@ -29,8 +29,6 @@ substs = configuration_data()
 substs.set('PACKAGE_URL',          'https://www.freedesktop.org/wiki/Software/systemd')
 substs.set('PACKAGE_VERSION',      meson.project_version())
 
-m4_defines = []
-
 #####################################################################
 
 # Try to install the git pre-commit hook
@@ -67,10 +65,8 @@ endif
 
 sysvinit_path = get_option('sysvinit-path')
 sysvrcnd_path = get_option('sysvrcnd-path')
-have = sysvinit_path != '' and sysvrcnd_path != ''
-conf.set10('HAVE_SYSV_COMPAT', have,
+conf.set10('HAVE_SYSV_COMPAT', sysvinit_path != '' and sysvrcnd_path != '',
            description : 'SysV init scripts and rcN.d links are supported')
-m4_defines += have ? ['-DHAVE_SYSV_COMPAT'] : []
 
 # join_paths ignore the preceding arguments if an absolute component is
 # encountered, so this should canonicalize various paths when they are
@@ -754,13 +750,8 @@ else
 endif
 substs.set('USERS_GID', users_gid)
 
-if get_option('adm-group')
-        m4_defines += ['-DENABLE_ADM_GROUP']
-endif
-
-if get_option('wheel-group')
-        m4_defines += ['-DENABLE_WHEEL_GROUP']
-endif
+conf.set10('ENABLE_ADM_GROUP', get_option('adm-group'))
+conf.set10('ENABLE_WHEEL_GROUP', get_option('wheel-group'))
 
 substs.set('DEV_KVM_MODE', get_option('dev-kvm-mode'))
 substs.set('GROUP_RENDER_MODE', get_option('group-render-mode'))
@@ -828,7 +819,6 @@ else
         libseccomp = []
 endif
 conf.set10('HAVE_SECCOMP', have)
-m4_defines += have ? ['-DHAVE_SECCOMP'] : []
 
 want_selinux = get_option('selinux')
 if want_selinux != 'false' and not fuzzer_build
@@ -841,7 +831,6 @@ else
         libselinux = []
 endif
 conf.set10('HAVE_SELINUX', have)
-m4_defines += have ? ['-DHAVE_SELINUX'] : []
 
 want_apparmor = get_option('apparmor')
 if want_apparmor != 'false' and not fuzzer_build
@@ -853,12 +842,10 @@ else
         libapparmor = []
 endif
 conf.set10('HAVE_APPARMOR', have)
-m4_defines += have ? ['-DHAVE_APPARMOR'] : []
 
 smack_run_label = get_option('smack-run-label')
 if smack_run_label != ''
         conf.set_quoted('SMACK_RUN_LABEL', smack_run_label)
-        m4_defines += ['-DHAVE_SMACK_RUN_LABEL']
 endif
 
 want_polkit = get_option('polkit')
@@ -885,7 +872,6 @@ else
         libacl = []
 endif
 conf.set10('HAVE_ACL', have)
-m4_defines += have ? ['-DHAVE_ACL'] : []
 
 want_audit = get_option('audit')
 if want_audit != 'false' and not fuzzer_build
@@ -930,7 +916,6 @@ else
         libpam_misc = []
 endif
 conf.set10('HAVE_PAM', have)
-m4_defines += have ? ['-DHAVE_PAM'] : []
 
 want_microhttpd = get_option('microhttpd')
 if want_microhttpd != 'false' and not fuzzer_build
@@ -943,7 +928,6 @@ else
         libmicrohttpd = []
 endif
 conf.set10('HAVE_MICROHTTPD', have)
-m4_defines += have ? ['-DHAVE_MICROHTTPD'] : []
 
 want_libcryptsetup = get_option('libcryptsetup')
 if want_libcryptsetup != 'false' and not fuzzer_build
@@ -968,7 +952,6 @@ else
         libcurl = []
 endif
 conf.set10('HAVE_LIBCURL', have)
-m4_defines += have ? ['-DHAVE_LIBCURL'] : []
 
 want_libidn = get_option('libidn')
 want_libidn2 = get_option('libidn2')
@@ -985,7 +968,6 @@ else
         libidn = []
 endif
 conf.set10('HAVE_LIBIDN', have)
-m4_defines += have ? ['-DHAVE_LIBIDN'] : []
 if not have and want_libidn2 != 'false' and not fuzzer_build
         # libidn is used for both libidn and libidn2 objects
         libidn = dependency('libidn2',
@@ -995,7 +977,6 @@ else
         have = false
 endif
 conf.set10('HAVE_LIBIDN2', have)
-m4_defines += have ? ['-DHAVE_LIBIDN2'] : []
 
 want_libiptc = get_option('libiptc')
 if want_libiptc != 'false' and not fuzzer_build
@@ -1007,7 +988,6 @@ else
         libiptc = []
 endif
 conf.set10('HAVE_LIBIPTC', have)
-m4_defines += have ? ['-DHAVE_LIBIPTC'] : []
 
 want_qrencode = get_option('qrencode')
 if want_qrencode != 'false' and not fuzzer_build
@@ -1234,15 +1214,9 @@ foreach term : ['utmp',
         have = get_option(term)
         name = 'ENABLE_' + term.underscorify().to_upper()
         conf.set10(name, have)
-        m4_defines += have ? ['-D' + name] : []
 endforeach
 
-if get_option('timedated') or get_option('timesyncd')
-        conf.set10('ENABLE_TIMEDATECTL', true)
-        m4_defines += ['-DENABLE_TIMEDATECTL']
-else
-        conf.set10('ENABLE_TIMEDATECTL', false)
-endif
+conf.set10('ENABLE_TIMEDATECTL', get_option('timedated') or get_option('timesyncd'))
 
 want_tests = get_option('tests')
 install_tests = get_option('install-tests')
@@ -1289,6 +1263,8 @@ config_h = configure_file(
         output : 'config.h',
         configuration : conf)
 
+meson_apply_m4 = find_program('tools/meson-apply-m4.sh')
+
 includes = include_directories('src/basic',
                                'src/shared',
                                'src/systemd',

src/core/meson.build

@@ -127,7 +127,7 @@ load_fragment_gperf_gperf = custom_target(
         'load-fragment-gperf.gperf',
         input : 'load-fragment-gperf.gperf.m4',
         output: 'load-fragment-gperf.gperf',
-        command : [m4, '-P'] + m4_defines + ['@INPUT@'],
+        command : [meson_apply_m4, config_h, '@INPUT@'],
         capture : true)
 
 load_fragment_gperf_c = custom_target(

src/login/meson.build

@@ -98,7 +98,7 @@ if conf.get('ENABLE_LOGIND') == 1
                 '73-seat-late.rules',
                 input : '73-seat-late.rules.m4',
                 output: '73-seat-late.rules',
-                command : [m4, '-P'] + m4_defines + ['@INPUT@'],
+                command : [meson_apply_m4, config_h, '@INPUT@'],
                 capture : true,
                 install : true,
                 install_dir : udevrulesdir)
@@ -107,7 +107,7 @@ if conf.get('ENABLE_LOGIND') == 1
                 'systemd-user',
                 input : 'systemd-user.m4',
                 output: 'systemd-user',
-                command : [m4, '-P'] + m4_defines + ['@INPUT@'],
+                command : [meson_apply_m4, config_h, '@INPUT@'],
                 capture : true,
                 install : pamconfdir != 'no',
                 install_dir : pamconfdir)

sysusers.d/meson.build

@@ -28,7 +28,7 @@ foreach file : m4_files
                 'sysusers.d_' + file,
                 input : file + '.m4',
                 output: file,
-                command : [m4, '-P'] + m4_defines + ['@INPUT@'],
+                command : [meson_apply_m4, config_h, '@INPUT@'],
                 capture : true,
                 install : enable_sysusers,
                 install_dir : sysusersdir)

tmpfiles.d/meson.build

@@ -37,7 +37,7 @@ foreach pair : m4_files
                         'tmpfiles.d_' + pair[0],
                          input : pair[0] + '.m4',
                          output: pair[0],
-                         command : [m4, '-P'] + m4_defines + ['@INPUT@'],
+                         command : [meson_apply_m4, config_h, '@INPUT@'],
                          capture : true,
                          install : true,
                          install_dir : tmpfilesdir)

tools/meson-apply-m4.sh

@@ -0,0 +1,24 @@
+#!/bin/sh
+set -eu
+
+CONFIG=$1
+TARGET=$2
+
+if [ $# -ne 2 ]; then
+        echo 'Invalid number of arguments.'
+        exit 1
+fi
+
+if [ ! -f $CONFIG ]; then
+        echo "$CONFIG not found."
+        exit 2
+fi
+
+if [ ! -f $TARGET ]; then
+        echo "$TARGET not found."
+        exit 3
+fi
+
+DEFINES=$(awk '$1 == "#define" && $3 == "1" { printf "-D%s ", $2 }' $CONFIG)
+
+m4 -P $DEFINES $TARGET

units/meson.build

@@ -272,7 +272,7 @@ foreach tuple : m4_units
                 file,
                 input : input,
                 output: file,
-                command : [m4, '-P'] + m4_defines + ['@INPUT@'],
+                command : [meson_apply_m4, config_h, '@INPUT@'],
                 capture : true,
                 install : install,
                 install_dir : systemunitdir)