meson: run build scripts through their interpreter

When a script declared with files() is the first element of a command, meson
replaces it with the script's absolute path. When the source and build
directories are reconfigured at a different absolute path, the command lines
of the jinja2 templates and of most generators change. ninja then runs the
templates and generators again. Some of the generators also get absolute
directories as arguments.

Let's run the scripts through python or bash, the same way most of our
generators already do. meson then passes the script relative to the build
directory. We also pass the directory arguments relative to the build
directory.

hwdb.d/meson.build

@@ -49,7 +49,7 @@ hwdb_files_test = files(
 if conf.get('ENABLE_HWDB') == 1
         auto_suspend_rules = custom_target(
                 output : '60-autosuspend-chromiumos.hwdb',
-                command : make_autosuspend_rules_py,
+                command : [python, make_autosuspend_rules_py],
                 capture : true,
                 install : true,
                 install_dir: udevhwdbdir,

man/meson.build

@@ -120,13 +120,13 @@ systemd_directives_xml = custom_target(
         input : ['directives-template.xml', source_xml_files],
         output : 'systemd.directives.xml',
         depends : man_page_depends,
-        command : [make_directive_index_py, '@OUTPUT@', '@INPUT@'])
+        command : [python, make_directive_index_py, '@OUTPUT@', '@INPUT@'])
 
 nonindex_xml_files = source_xml_files + [systemd_directives_xml]
 systemd_index_xml = custom_target(
         input : nonindex_xml_files,
         output : 'systemd.index.xml',
-        command : [make_man_index_py, '@OUTPUT@'] + nonindex_xml_files)
+        command : [python, make_man_index_py, '@OUTPUT@'] + nonindex_xml_files)
 
 foreach tuple : xsltproc.found() and have_lxml ? [['systemd.directives', '7', systemd_directives_xml],
                                                   ['systemd.index',      '7', systemd_index_xml]] : []

meson.build

@@ -1847,7 +1847,7 @@ config_h = configure_file(
 
 userspace_c_args += ['-include', 'config.h']
 
-jinja2_cmdline = [meson_render_jinja2_py, config_h]
+jinja2_cmdline = [python, meson_render_jinja2_py, config_h]
 
 userspace = declare_dependency(
         compile_args : userspace_c_args,
@@ -3076,7 +3076,7 @@ if not meson.is_cross_build()
                 output : fs.name(dbus_interfaces_dir),
                 install : dbus_interfaces_dir != 'no',
                 install_dir : fs.parent(dbus_interfaces_dir),
-                command : [dbus_exporter_py, '@OUTPUT@', dbus_programs])
+                command : [python, dbus_exporter_py, '@OUTPUT@', dbus_programs])
 endif
 
 custom_target(
@@ -3084,8 +3084,9 @@ custom_target(
         capture : true,
         install : want_tests != 'no' and install_tests,
         install_dir : testdata_dir,
-        command : [meson_extract_unit_files_py,
-                   meson.project_build_root()])
+        command : [python,
+                   meson_extract_unit_files_py,
+                   '.'])
 
 #####################################################################
 

src/basic/meson.build

@@ -158,7 +158,7 @@ foreach item : [
                 gperf_file = custom_target(
                         input : list_txt,
                         output : '@0@-from-name.gperf'.format(item[0]),
-                        command : [generate_gperfs, item[0], item[2], '@INPUT@'] + item[3],
+                        command : [python, generate_gperfs, item[0], item[2], '@INPUT@'] + item[3],
                         capture : true)
 
                 target = custom_target(
@@ -184,7 +184,8 @@ basic_sources += generated_gperf_headers
 filesystem_sets_py = files('filesystem-sets.py')
 filesystem_sets_c = custom_target(
         output : 'filesystem-sets.c',
-        command : [filesystem_sets_py,
+        command : [python,
+                   filesystem_sets_py,
                    'fs-type-to-string',
                    'filesystem-sets',
                    'fs-in-group'],
@@ -192,7 +193,8 @@ filesystem_sets_c = custom_target(
 
 filesystems_gperf_gperf = custom_target(
         output : 'filesystems-gperf.gperf',
-        command : [filesystem_sets_py,
+        command : [python,
+                   filesystem_sets_py,
                    'gperf'],
         capture : true)
 

src/boot/meson.build

@@ -31,8 +31,9 @@ if conf.get('ENABLE_UKIFY') == 1
         test_hwids_section_c = custom_target(
                 input : ['hwids/test/device1.json', 'hwids/test/device2.json', 'hwids/test/device3.json', 'hwids/test/device4.json'],
                 output : 'test-hwids-section.c',
-                command : [files('generate-hwids-section.py'),
-                           meson.current_source_dir()/'hwids/test'],
+                command : [python,
+                           files('generate-hwids-section.py'),
+                           relative_source_path / 'src/boot/hwids/test'],
                 capture : true,
                 build_by_default : want_tests != 'false')
         install_subdir('hwids',
@@ -470,6 +471,7 @@ foreach efi_elf_binary : efi_elf_binaries
                 install_dir : bootlibdir,
                 install_tag : 'systemd-boot',
                 command : [
+                        pyelftools,
                         elf2efi_py,
                         f'--version-major=@project_major_version@',
                         f'--version-minor=@project_minor_version@',

src/libsystemd/meson.build

@@ -161,8 +161,6 @@ libsystemd_static = static_library(
                         userspace],
         build_by_default : false)
 
-libsystemd_dir_path = meson.current_source_dir()
-
 libsystemd_sym = files('libsystemd.sym')
 libsystemd_sym_path = relative_source_path / 'src/libsystemd/libsystemd.sym'
 

src/libudev/meson.build

@@ -23,6 +23,7 @@ libudev_sym = files('libudev.sym')
 libudev_sym_path = relative_source_path / 'src/libudev/libudev.sym'
 
 install_headers('libudev.h')
+libudev_h = files('libudev.h')
 libudev_h_path = libudev_dir_path / 'libudev.h'
 
 libudev_basic = static_library(

src/shared/meson.build

@@ -293,7 +293,8 @@ endif
 syscall_list_inc = custom_target(
         input : syscall_list_txt,
         output : 'syscall-list.inc',
-        command : [files('generate-syscall-list.py'),
+        command : [python,
+                   files('generate-syscall-list.py'),
                    '@INPUT@'],
         capture : true)
 
@@ -330,7 +331,7 @@ ip_protocol_list_txt = custom_target(
 gperf_file = custom_target(
         input : ip_protocol_list_txt,
         output : 'ip-protocol-from-name.gperf',
-        command : [generate_gperfs, 'ip_protocol', 'IPPROTO_', '@INPUT@', '<netinet/in.h>'],
+        command : [python, generate_gperfs, 'ip_protocol', 'IPPROTO_', '@INPUT@', '<netinet/in.h>'],
         capture : true)
 
 target1 = custom_target(
@@ -381,7 +382,8 @@ dns_type_list_txt = custom_target(
 gperf_file = custom_target(
         input : dns_type_list_txt,
         output : 'dns_type-from-name.gperf',
-        command : [files('generate-dns_type-gperf.py'),
+        command : [python,
+                   files('generate-dns_type-gperf.py'),
                    'dns_type',
                    'DNS_TYPE_',
                    '@INPUT@'],

src/test/meson.build

@@ -32,22 +32,24 @@ test_libsystemd_sym_c = custom_target(
                  systemd_headers,
                  libsystemd_sources],
         output : 'test-libsystemd-sym.c',
-        command : [generate_sym_test_py,
+        command : [python,
+                   generate_sym_test_py,
                    '@INPUT0@',
-                   libsystemd_dir_path,
+                   relative_source_path / 'src/libsystemd',
                    systemd_headers],
         capture : true,
         build_by_default : want_tests != 'false')
 
 test_libudev_sym_c = custom_target(
         input : [libudev_sym,
-                 libudev_h_path,
+                 libudev_h,
                  libudev_sources],
         output : 'test-libudev-sym.c',
-        command : [generate_sym_test_py,
+        command : [python,
+                   generate_sym_test_py,
                    '@INPUT0@',
-                   libudev_dir_path,
-                   libudev_h_path],
+                   relative_source_path / 'src/libudev',
+                   '@INPUT1@'],
         capture : true,
         build_by_default : want_tests != 'false')
 

src/version/meson.build

@@ -7,6 +7,8 @@ version_h = custom_target('version',
         output : 'version.h',
         capture : true,
         command : [
+                env,
+                'bash',
                 vcs_tag_sh,
                 '@INPUT@',
                 get_option('mode'),

test/fuzz/meson.build

@@ -12,7 +12,7 @@ directives = [['fuzz-network-parser', 'directives.network', networkd_network_gpe
 foreach tuple : directives
         directive = custom_target(
                 output: tuple[1],
-                command: [generate_directives_py, tuple[2]],
+                command: [python, generate_directives_py, tuple[2]],
                 capture: true)
 
         dict = { 'directives' : [directive] }
@@ -26,7 +26,7 @@ foreach section : ['Automount', 'Mount', 'Path', 'Scope', 'Service', 'Slice', 'S
         name = f'directives.@unit_type@'
         unit_directives += custom_target(
                 output: name,
-                command: [generate_directives_py, load_fragment_gperf_gperf, sec_rx, unit_type],
+                command: [python, generate_directives_py, load_fragment_gperf_gperf, sec_rx, unit_type],
                 capture: true)
 endforeach
 dict = { 'directives' : unit_directives }