[pve-devel] [PATCH v2 container] fix #4192: revamp check for systemd version

[Leo Nunner]

Instead of iterating through several folders, it might just be easier to
check the ldd output of /sbin/init and getting the version from there.
Furthermore, the regex for checking the version has been adapted so that
it's more precise.

Signed-off-by: Leo Nunner <l.nunner at proxmox.com>
---
This solution does actually feel cleaner than manually checking all the folders
every time.

 src/PVE/LXC/Setup/Base.pm | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/src/PVE/LXC/Setup/Base.pm b/src/PVE/LXC/Setup/Base.pm
index cc12914..44b88d9 100644
--- a/src/PVE/LXC/Setup/Base.pm
+++ b/src/PVE/LXC/Setup/Base.pm
@@ -514,19 +514,26 @@ sub clear_machine_id {
     }
 }
 
-# tries to guess the systemd (major) version based on the existence of
-# (/usr)?/lib/systemd/libsystemd-shared<version>.so. It was introduced in v231.
+# tries to guess the systemd (major) version based on the
+# libsystemd-shared<version>.so linked with /sbin/init
 sub get_systemd_version {
     my ($self) = @_;
 
-    my $sd_lib_dir = $self->ct_is_directory("/lib/systemd") ?
-	"/lib/systemd" : "/usr/lib/systemd";
-    my $libsd = PVE::Tools::dir_glob_regex($sd_lib_dir, "libsystemd-shared-.+\.so");
-    if (defined($libsd) && $libsd =~ /libsystemd-shared-(\d+)(?:\..*)?\.so/) {
-	return $1;
-    }
-
-    return undef;
+    my $version = undef;
+    PVE::Tools::run_command(
+	[
+	    'ldd',
+	    '/sbin/init'
+	],
+	outfunc => sub {
+	    my $line = shift;
+	    if ($line =~ /^\s*libsystemd-shared-(\d+)(?:\.[a-zA-Z0-9]*)?\.so/) {
+		$version = $1;
+	    }},
+	errmsg => "ldd on /sbin/init failed"
+    );
+
+    return $version;
 }
 
 sub unified_cgroupv2_support {
-- 
2.30.2