[PATCH installer 17/21] low-level-installer: add support for restoring backups

[Shannon Sterz <s.sterz@proxmox.com>]

and integrate it with the tui restoring installer.

Signed-off-by: Shannon Sterz <s.sterz@proxmox.com>
---
 Proxmox/Install.pm        | 63 +++++++++++++++++++++++++++++++++++++--
 Proxmox/Install/Config.pm |  6 ++++
 2 files changed, 66 insertions(+), 3 deletions(-)

diff --git a/Proxmox/Install.pm b/Proxmox/Install.pm
index 7bb8e29..1d4f56b 100644
--- a/Proxmox/Install.pm
+++ b/Proxmox/Install.pm
@@ -849,6 +849,9 @@ sub extract_data {
     my $bootloader_err;
     my $diskcount = 0;
 
+    my $backup_mp = Proxmox::Install::Config::get_restore_mount_point();
+    my $kapi;
+
     eval {
         my $maxper = 0.25;
 
@@ -1488,7 +1491,7 @@ _EOD
 
         my $ask_for_patience = "";
         $ask_for_patience = " (multiple disks detected, please be patient)" if $diskcount > 3;
-        update_progress(0.8, 0.95, 1, "make system bootable$ask_for_patience");
+        update_progress(0.5, 0.95, 1, "make system bootable$ask_for_patience");
 
         setup_proxmox_first_boot_service($targetdir);
         stage_subscription_key($targetdir);
@@ -1538,7 +1541,6 @@ _EOD
         diversion_remove($targetdir, "/usr/sbin/update-grub");
         diversion_remove($targetdir, "/usr/sbin/update-initramfs");
 
-        my $kapi;
         foreach my $fn (<$targetdir/lib/modules/*>) {
             if ($fn =~ m!/(\d+\.\d+\.\d+-\d+(?:-\w+)?-pve)$!) {
                 die "found multiple kernels\n" if defined($kapi);
@@ -1610,6 +1612,10 @@ _EOD
 
         diversion_remove($targetdir, "/sbin/start-stop-daemon");
 
+        # return early, the next setup steps are overwritten by the backup and might fail (for
+        # example, setting a root password).
+        return if defined($backup_mp);
+
         setup_root_password($targetdir);
 
         # set root ssh keys
@@ -1697,7 +1703,9 @@ _EOD
 
     my $err = $@;
 
-    update_progress(1, 0, 1, "installation finished");
+    if ($err || !defined($kapi) || !defined($backup_mp)) {
+        update_progress(1, 0, 1, "installation finished");
+    }
 
     print STDERR $err if $err && $err ne "\n";
 
@@ -1709,6 +1717,55 @@ _EOD
             "chroot $targetdir /usr/bin/dpkg-query -W --showformat='\${package}\n'> final.pkglist");
     }
 
+    if (!$err && defined($kapi) && defined($backup_mp)) {
+        eval {
+            update_progress(0.8, 0.95, 1, "restoring backup, this may take a little while...");
+            my @backup_files = glob("$backup_mp/*");
+
+            foreach my $file (@backup_files) {
+                if ($file !~ m/\/(dev|run|tmp|sys|proc|mnt)\/?$/) {
+                    syscmd(["cp", "--archive", "--recursive", "--force", $file, $targetdir]) ==
+                        0
+                        || die("could not restore backup - $!\n");
+                }
+            }
+
+            # Copy the latest pmxcfs backup into the "live" position.
+            my @backed_up_dbs =
+                sort(glob($backup_mp . "/var/lib/pve-cluster/backup/config-backup*.db"));
+            my $db = $backed_up_dbs[-1];
+
+            die "could not restore live pmxcfs db.\n" if !defined($db);
+
+            syscmd([
+                "cp", "--archive", "--force", $db, "$targetdir/var/lib/pve-cluster/config.db",
+                ]) == 0
+                || die("could not restore live pmxcfs backup - $!\n");
+
+            # unmount backup location as we are done restoring. ignore failures,
+            # nothing bad should happen if we reboot here while it's still
+            # mounted.
+            syscmd(["umount", "$backup_mp"]);
+
+            if (!is_test_mode()) {
+                syscmd("mount -n --bind /dev $targetdir/dev"); # re-bind mount dev
+
+                syscmd("chroot $targetdir /usr/sbin/update-initramfs -c -k $kapi") == 0
+                    || die "unable to install initramfs on restore\n";
+
+                syscmd("chroot $targetdir /usr/sbin/update-grub") == 0
+                    || die "unable to update boot loader config on restore\n";
+            }
+        };
+
+        $err = $@;
+        update_progress(1, 0, 1, "installation finished");
+
+        if (!is_test_mode()) {
+            syscmd("umount $targetdir/dev"); # unmount again
+        }
+    }
+
     syscmd("umount $targetdir/run");
     syscmd("umount $targetdir/mnt/hostrun");
     syscmd("umount $targetdir/tmp/pkg");
diff --git a/Proxmox/Install/Config.pm b/Proxmox/Install/Config.pm
index dba3692..00b713f 100644
--- a/Proxmox/Install/Config.pm
+++ b/Proxmox/Install/Config.pm
@@ -121,6 +121,9 @@ my sub init_cfg {
             # and the service files in the proxmox-first-boot package
             ordering_target => 'multi-user', # one of `network-pre`, `network-online` or `multi-user`
         },
+
+        # directory to restore contents from
+        restore_mount_point => undef,
     };
 
     $initial = parse_kernel_cmdline($initial);
@@ -310,4 +313,7 @@ sub get_first_boot_opt {
     return defined($k) ? $opts->{$k} : $opts;
 }
 
+sub get_restore_mount_point { return get('restore_mount_point'); }
+sub set_restore_mount_point { set_key('restore_mount_point', $_[0]); }
+
 1;
-- 
2.47.3