tree-wide: Add initrd presets

Currently, when running "systemctl preset-all --root=xxx" in mkosi
to enable/disable units for initrds, the system presets are used.
The problem with this approach is that the system presets are written
for the system, and that is not necessarily ideal for an initrd, but we
still want to use the same packages in the initrd that we install in the
system, so let's introduce a separate directory for initrd presets which
is used to pick up preset files from when we detect that we're configuring
an initrd (by looking for /etc/initrd-release).

We also introduce a systemd preset file for the initrd, which is based on
the system one, except with all the stuff unnecessary for the initrd removed.

docs/PRESET.md

@@ -29,7 +29,7 @@ systemd 32 and newer support package "preset" policies.
 These encode which units shall be enabled by default when they are installed, and which units shall not be enabled.
 
 Preset files may be written for specific distributions, for specific spins or for specific sites, in order to enforce different policies as needed.
-Preset policies are stored in .preset files in /usr/lib/systemd/system-preset/.
+Preset policies are stored in .preset files in /usr/lib/systemd/system-preset/ (or /usr/lib/systemd/initrd-preset/ for initrds).
 If no policy exists the default implied policy of "enable everything" is enforced, i.e. in Debian style.
 
 The policy encoded in preset files is applied to a unit by invoking "systemctl preset ".

man/systemd.preset.xml

@@ -30,6 +30,10 @@
       <member><filename>/run/systemd/user-preset/*.preset</filename></member>
       <member><filename>/usr/local/lib/systemd/user-preset/*.preset</filename></member>
       <member><filename>/usr/lib/systemd/user-preset/*.preset</filename></member>
+      <member><filename>/etc/systemd/initrd-preset/*.preset</filename></member>
+      <member><filename>/run/systemd/initrd-preset/*.preset</filename></member>
+      <member><filename>/usr/local/lib/systemd/initrd-preset/*.preset</filename></member>
+      <member><filename>/usr/lib/systemd/initrd-preset/*.preset</filename></member>
     </simplelist></para>
   </refsynopsisdiv>
 

meson.build

@@ -172,6 +172,7 @@ systemshutdowndir = libexecdir / 'system-shutdown'
 systemsleepdir = libexecdir / 'system-sleep'
 systemunitdir = prefixdir / 'lib/systemd/system'
 systempresetdir = prefixdir / 'lib/systemd/system-preset'
+initrdpresetdir = prefixdir / 'lib/systemd/initrd-preset'
 udevlibexecdir = prefixdir / 'lib/udev'
 udevrulesdir = udevlibexecdir / 'rules.d'
 udevhwdbdir = udevlibexecdir / 'hwdb.d'

presets/90-systemd-initrd.preset

@@ -0,0 +1,38 @@
+#  SPDX-License-Identifier: LGPL-2.1-or-later
+#
+#  This file is part of systemd.
+#
+#  systemd is free software; you can redistribute it and/or modify it
+#  under the terms of the GNU Lesser General Public License as published by
+#  the Free Software Foundation; either version 2.1 of the License, or
+#  (at your option) any later version.
+
+# Settings for systemd units distributed with systemd itself, specific to initrds.
+
+enable systemd-journald-audit.socket
+enable systemd-network-generator.service
+enable systemd-networkd.service
+enable systemd-networkd-wait-online.service
+enable systemd-pstore.service
+enable systemd-resolved.service
+enable systemd-tpm2-clear.service
+
+disable console-getty.service
+disable debug-shell.service
+
+disable exit.target
+disable halt.target
+disable kexec.target
+disable poweroff.target
+enable reboot.target
+disable rescue.target
+
+disable proc-sys-fs-binfmt_misc.mount
+
+disable syslog.socket
+
+disable systemd-boot-check-no-failures.service
+disable systemd-journal-gatewayd.*
+disable systemd-journal-remote.*
+disable systemd-journal-upload.*
+disable systemd-time-wait-sync.service

presets/meson.build

@@ -3,5 +3,10 @@
 install_data('90-systemd.preset',
              install_dir : systempresetdir)
 
-install_data('user/90-systemd.preset',
+install_data('90-systemd-user.preset',
-             install_dir : userpresetdir)
+             install_dir : userpresetdir,
+             rename : '90-systemd.preset')
+
+install_data('90-systemd-initrd.preset',
+             install_dir : initrdpresetdir,
+             rename : '90-systemd.preset')

src/core/systemd.pc.in

@@ -31,6 +31,9 @@ systemdsystemunitdir=${systemd_system_unit_dir}
 systemd_system_preset_dir=${prefix}/lib/systemd/system-preset
 systemdsystempresetdir=${systemd_system_preset_dir}
 
+systemd_initrd_preset_dir=${prefix}/lib/systemd/initrd-preset
+systemdinitrdpresetdir=${systemd_initrd_preset_dir}
+
 systemd_user_unit_dir=${prefix}/lib/systemd/user
 systemduserunitdir=${systemd_user_unit_dir}
 

src/libsystemd/sd-path/sd-path.c

@@ -302,6 +302,10 @@ static int get_path(uint64_t type, char **buffer, const char **ret) {
                 *ret = PREFIX_NOSLASH "/lib/systemd/user-preset";
                 return 0;
 
+        case SD_PATH_SYSTEMD_INITRD_PRESET:
+                *ret = PREFIX_NOSLASH "/lib/systemd/initrd-preset";
+                return 0;
+
         case SD_PATH_SYSTEMD_SYSTEM_CONF:
                 *ret = SYSTEM_CONFIG_UNIT_DIR;
                 return 0;

src/path/path-tool.c

@@ -75,6 +75,7 @@ static const char* const path_table[_SD_PATH_MAX] = {
         [SD_PATH_SYSTEMD_USER_UNIT]                           = "systemd-user-unit",
         [SD_PATH_SYSTEMD_USER_PRESET]                         = "systemd-user-preset",
         [SD_PATH_SYSTEMD_USER_CONF]                           = "systemd-user-conf",
+        [SD_PATH_SYSTEMD_INITRD_PRESET]                       = "systemd-initrd-preset",
 
         [SD_PATH_SYSTEMD_SEARCH_SYSTEM_UNIT]                  = "systemd-search-system-unit",
         [SD_PATH_SYSTEMD_SEARCH_USER_UNIT]                    = "systemd-search-user-unit",

src/shared/install.c

@@ -3284,16 +3284,22 @@ static int split_pattern_into_name_and_instances(const char *pattern, char **out
 }
 
 static int presets_find_config(RuntimeScope scope, const char *root_dir, char ***files) {
+        static const char* const initrd_dirs[] = { CONF_PATHS("systemd/initrd-preset"), NULL };
         static const char* const system_dirs[] = { CONF_PATHS("systemd/system-preset"), NULL };
         static const char* const user_dirs[] = { CONF_PATHS("systemd/user-preset"), NULL };
         const char* const* dirs;
+        int r;
 
         assert(scope >= 0);
         assert(scope < _RUNTIME_SCOPE_MAX);
 
-        if (scope == RUNTIME_SCOPE_SYSTEM)
+        if (scope == RUNTIME_SCOPE_SYSTEM) {
-                dirs = system_dirs;
+                r = chase_and_access("/etc/initrd-release", root_dir, CHASE_PREFIX_ROOT, F_OK, /* ret_path= */ NULL);
-        else if (IN_SET(scope, RUNTIME_SCOPE_GLOBAL, RUNTIME_SCOPE_USER))
+                if (r < 0 && r != -ENOENT)
+                        return r;
+
+                dirs = r >= 0 ? initrd_dirs : system_dirs;
+        } else if (IN_SET(scope, RUNTIME_SCOPE_GLOBAL, RUNTIME_SCOPE_USER))
                 dirs = user_dirs;
         else
                 assert_not_reached();

src/shared/pretty-print.c

@@ -372,7 +372,7 @@ static int guess_type(const char **name, char ***ret_prefixes, bool *ret_is_coll
         } else if (path_equal(n, "systemd/relabel-extra.d")) {
                 coll = run = true;
                 ext = ".relabel";
-        } else if (PATH_IN_SET(n, "systemd/system-preset", "systemd/user-preset")) {
+        } else if (PATH_IN_SET(n, "systemd/system-preset", "systemd/user-preset", "systemd/initrd-preset")) {
                 coll = true;
                 ext = ".preset";
         }

src/systemd/sd-path.h

@@ -88,6 +88,7 @@ enum {
         SD_PATH_SYSTEMD_USER_UNIT,
         SD_PATH_SYSTEMD_USER_PRESET,
         SD_PATH_SYSTEMD_USER_CONF,
+        SD_PATH_SYSTEMD_INITRD_PRESET,
 
         SD_PATH_SYSTEMD_SEARCH_SYSTEM_UNIT,
         SD_PATH_SYSTEMD_SEARCH_USER_UNIT,