tree-wide: make specifier expansion --root= aware

This fixes repart's, systemctl's, sysusers' and tmpfiles' specifier
expansion to honour the root dir specified with --root=. This is
relevant for specifiers such as %m, %o, … which are directly sourced
from files on disk.

This doesn't try to be overly smart: specifiers referring to runtime
concepts (i.e. boot ID, architecture, hostname) rather than files on the
medium are left as is. There's certainly a point to be made that they
should fail in case --root= is specified, but I am not entirely convinced
about that, and it's certainly something we can look into later if
there's reason to.

I wondered for a while how to hook this up best, but given that quite a
large number of specifiers resolve to data from files on disks, and most
of our tools needs this, I ultimately decided to make the root dir a
first class parameter to specifier_printf().

Replaces: #16187
Fixes: #16183

1 files changed, 2 insertions, 2 deletions

diff --git a/src/test/test-unit-name.c b/src/test/test-unit-name.c
index d737043220..0077c4c5e3 100644
--- a/src/test/test-unit-name.c
+++ b/src/test/test-unit-name.c
@@ -228,8 +228,8 @@ static int test_unit_printf(void) {
 
         log_info("/* %s */", __func__);
 
-        assert_se(specifier_machine_id('m', NULL, NULL, &mid) >= 0 && mid);
-        assert_se(specifier_boot_id('b', NULL, NULL, &bid) >= 0 && bid);
+        assert_se(specifier_machine_id('m', NULL, NULL, NULL, &mid) >= 0 && mid);
+        assert_se(specifier_boot_id('b', NULL, NULL, NULL, &bid) >= 0 && bid);
         assert_se(host = gethostname_malloc());
         assert_se(user = uid_to_name(getuid()));
         assert_se(group = gid_to_name(getgid()));