[pmg-devel] [PATCH pmg-api v2] utils: check if file changed before reusing its hash

[Maximiliano Sandoval <m.sandoval@proxmox.com>]

We cache the hash of this file, it makes sense to first check if the
file changed via `stat` and recompute the hash if needed.

Signed-off-by: Maximiliano Sandoval <m.sandoval@proxmox.com>
---
 Differences from v1:
   - Dont add unnecesary variables or functions
   - Use hash slices

 src/PMG/Utils.pm | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/PMG/Utils.pm b/src/PMG/Utils.pm
index c19b31f..d9c9d2d 100644
--- a/src/PMG/Utils.pm
+++ b/src/PMG/Utils.pm
@@ -1353,14 +1353,22 @@ sub scan_journal_for_rbl_rejects {
 }
 
 my $hwaddress;
+my $hwaddress_st = {};
 
 sub get_hwaddress {
+    my $fn = '/etc/ssh/ssh_host_rsa_key.pub';
+    my $st = stat($fn);
 
-    return $hwaddress if defined ($hwaddress);
+    if (defined($hwaddress)
+	&& $hwaddress_st->{mtime} == $st->mtime
+	&& $hwaddress_st->{ino} == $st->ino
+	&& $hwaddress_st->{dev} == $st->dev) {
+	return $hwaddress;
+    }
 
-    my $fn = '/etc/ssh/ssh_host_rsa_key.pub';
     my $sshkey = PVE::Tools::file_get_contents($fn);
     $hwaddress = uc(Digest::MD5::md5_hex($sshkey));
+    $hwaddress_st->@{'mtime', 'ino', 'dev'} = ($st->mtime, $st->ino, $st->dev);
 
     return $hwaddress;
 }
-- 
2.39.2