daemon: Respect systemd inhibitor locks

Today, non-interactive processes, including rpm-ostree, are not
inhibited by systemd inhibitor locks. systemd 248 added the
`--check-inhibitors` option to `systemctl` commands, which can be
used to make non-interactive proccesses check for shutdown/sleep
inhibitors. However, it also checks for `delay` mode inhibitors,
which isn't what we want. Replicate this logic prior to reboots,
but ignore `delay` mode inhibitors.

src/daemon/rpmostreed-daemon.cxx

@@ -815,6 +815,12 @@ rpmostreed_daemon_is_rebooting (RpmostreedDaemon *self)
   return self->rebooting;
 }
 
+GDBusConnection *
+rpmostreed_daemon_connection(void)
+{
+  g_assert (_daemon_instance->connection);
+  return _daemon_instance->connection;
+}
 
 void
 rpmostreed_daemon_run_until_idle_exit (RpmostreedDaemon *self)

src/daemon/rpmostreed-daemon.h

@@ -38,6 +38,7 @@ G_BEGIN_DECLS
 
 GType              rpmostreed_daemon_get_type       (void) G_GNUC_CONST;
 RpmostreedDaemon * rpmostreed_daemon_get            (void);
+GDBusConnection  * rpmostreed_daemon_connection     (void);
 gboolean           rpmostreed_get_client_uid        (RpmostreedDaemon *self,
                                                      const char       *client,
                                                      uid_t            *out_uid);

src/daemon/rpmostreed-transaction-types.cxx

@@ -546,7 +546,11 @@ rollback_transaction_execute (RpmostreedTransaction *transaction,
     }
 
   if (self->reboot)
-    rpmostreed_daemon_reboot (rpmostreed_daemon_get ());
+    {
+      if (!check_sd_inhibitor_locks (cancellable, error))
+        return FALSE;
+      rpmostreed_daemon_reboot (rpmostreed_daemon_get ());
+    }
 
   return TRUE;
 }
@@ -1526,7 +1530,11 @@ deploy_transaction_execute (RpmostreedTransaction *transaction,
         }
 
       if (deploy_has_bool_option (self, "reboot"))
-        rpmostreed_daemon_reboot (rpmostreed_daemon_get ());
+        {
+          if (!check_sd_inhibitor_locks (cancellable, error))
+            return FALSE;
+          rpmostreed_daemon_reboot (rpmostreed_daemon_get ());
+        }
     }
   else
     {
@@ -1928,7 +1936,11 @@ initramfs_etc_transaction_execute (RpmostreedTransaction *transaction,
     return FALSE;
 
   if (vardict_lookup_bool (self->options, "reboot", FALSE))
-    rpmostreed_daemon_reboot (rpmostreed_daemon_get ());
+    {
+      if (!check_sd_inhibitor_locks (cancellable, error))
+        return FALSE;
+      rpmostreed_daemon_reboot (rpmostreed_daemon_get ());
+    }
 
   return TRUE;
 }
@@ -2066,7 +2078,11 @@ initramfs_state_transaction_execute (RpmostreedTransaction *transaction,
     return FALSE;
 
   if (vardict_lookup_bool (self->options, "reboot", FALSE))
-    rpmostreed_daemon_reboot (rpmostreed_daemon_get ());
+    {
+      if (!check_sd_inhibitor_locks (cancellable, error))
+        return FALSE;
+      rpmostreed_daemon_reboot (rpmostreed_daemon_get ());
+    }
 
   return TRUE;
 }
@@ -2582,6 +2598,10 @@ finalize_deployment_transaction_execute (RpmostreedTransaction *transaction,
   OstreeSysroot *sysroot = rpmostreed_transaction_get_sysroot (transaction);
   OstreeRepo *repo = ostree_sysroot_repo (sysroot);
 
+  // Check for inhibitor locks before unlocking staged deployment.
+  if (!check_sd_inhibitor_locks (cancellable, error))
+    return FALSE;
+
   auto command_line = (const char*)
     vardict_lookup_ptr (self->options, "initiating-command-line", "&s");
 
@@ -2610,6 +2630,10 @@ finalize_deployment_transaction_execute (RpmostreedTransaction *transaction,
     return glnx_throw (error, "Expected staged base checksum %s, but found %s",
                        expected_checksum, checksum);
 
+  // Check for inhibitor locks before unlocking staged deployment.
+  if (!check_sd_inhibitor_locks (cancellable, error))
+    return FALSE;
+
   if (unlink (_OSTREE_SYSROOT_RUNSTATE_STAGED_LOCKED) < 0)
     {
       if (errno != ENOENT)
@@ -2802,7 +2826,11 @@ kernel_arg_transaction_execute (RpmostreedTransaction *transaction,
     return FALSE;
 
   if (vardict_lookup_bool (self->options, "reboot", FALSE))
-    rpmostreed_daemon_reboot (rpmostreed_daemon_get ());
+    {
+      if (!check_sd_inhibitor_locks (cancellable, error))
+        return FALSE;
+      rpmostreed_daemon_reboot (rpmostreed_daemon_get ());
+    }
 
   return TRUE;
 }

src/daemon/rpmostreed-utils.cxx

@@ -21,6 +21,7 @@
 #include "rpmostree-util.h"
 #include "rpmostreed-utils.h"
 #include "rpmostreed-errors.h"
+#include "rpmostreed-daemon.h"
 #include "libglnx.h"
 #include <systemd/sd-journal.h>
 #include <stdint.h>
@@ -609,3 +610,52 @@ rpmostreed_parse_revision (const char  *revision,
 out:
   return ret;
 }
+
+/* Throw an error if there exists systemd inhibitor locks in `block` mode only.
+ * Note: systemd 248 provides a `--check-inhibitors` option, but it also checks
+ * for inhibitors in `delay` mode, which isn't what we want. */
+gboolean
+check_sd_inhibitor_locks (GCancellable    *cancellable,
+                          GError         **error)
+{
+  GDBusConnection *connection = rpmostreed_daemon_connection ();
+  g_autoptr(GVariant) inhibitors_array_tuple = 
+    g_dbus_connection_call_sync (connection, "org.freedesktop.login1", "/org/freedesktop/login1",
+                                 "org.freedesktop.login1.Manager", "ListInhibitors",
+                                 NULL, (const GVariantType*)"(a(ssssuu))",
+                                 G_DBUS_CALL_FLAGS_NONE, -1, cancellable, error);
+  if (!inhibitors_array_tuple)
+    return glnx_prefix_error (error, "Checking systemd inhibitor locks");
+  else if (g_variant_n_children (inhibitors_array_tuple) < 1)
+    return glnx_throw (error, "LoadInhibitors returned empty tuple");
+  g_autoptr(GVariant) inhibitors_array =
+    g_variant_get_child_value (inhibitors_array_tuple, 0);
+
+  char *what;
+  char *who;
+  char *why;
+  char *mode;
+  int num_block_inhibitors = 0;
+  g_autoptr(GString) error_msg = g_string_new(NULL);
+  GVariantIter viter;
+  g_variant_iter_init (&viter, inhibitors_array);
+  while (g_variant_iter_loop (&viter, "(ssssuu)", &what, &who, &why, &mode, NULL, NULL))
+    {
+      // Only consider shutdown inhibitors in `block` mode.
+      if (strstr (what, "shutdown") && strcmp (mode, "block") == 0)
+        if (++num_block_inhibitors == 1)
+          g_string_append_printf (error_msg,
+                                  "Reboot blocked by a systemd inhibitor lock in `block` mode\n"
+                                  "Held by: %s\nReason: %s",
+                                  who, why);
+    }
+
+  if (num_block_inhibitors == 0)
+    return TRUE;
+  else if (num_block_inhibitors > 1)
+    g_string_append_printf (error_msg,
+                            "\nand %d other blocking inhibitor lock(s)\n"
+                            "Use `systemd-inhibit --list` to see details",
+                            num_block_inhibitors - 1);
+  return glnx_throw (error, "%s", error_msg->str);
+}

src/daemon/rpmostreed-utils.h

@@ -83,4 +83,7 @@ gboolean   rpmostreed_parse_revision (const char  *revision,
                                       char       **out_version,
                                       GError     **error);
 
+gboolean   check_sd_inhibitor_locks (GCancellable    *cancellable,
+                                     GError         **error);
+
 G_END_DECLS

tests/common/libvm.sh

@@ -98,8 +98,8 @@ EOF
 
   vm_setup
 
-  # XXX: hack around https://github.com/systemd/systemd/issues/14328
-  vm_cmd systemctl mask --now systemd-logind
+  # # XXX: hack around https://github.com/systemd/systemd/issues/14328
+  # vm_cmd systemctl mask --now systemd-logind
 
   # Some tests expect the ref to be on `vmcheck`. We should drop that
   # requirement, but for now let's just mangle the origin

tests/vmcheck/test-misc-2.sh

@@ -44,7 +44,7 @@ assert_streq "$(vm_get_booted_csum)" "${booted_csum}"
 vm_assert_journal_has_content $cursor 'Not finalizing; found /run/ostree/staged-deployment-locked'
 echo "ok locked rebase staging"
 
-# This also now tests custom client IDs in the journal.
+# This also tests custom client IDs in the journal and interaction with systemd inhibitor locks.
 cursor=$(vm_get_journal_cursor)
 vm_cmd env RPMOSTREE_CLIENT_ID=testing-agent-id \
        rpm-ostree deploy revision="${commit}" \
@@ -58,7 +58,15 @@ fi
 vm_cmd journalctl --after-cursor "'$cursor'" -u rpm-ostreed -o json | jq -r '.AGENT//""' > agent.txt
 assert_file_has_content agent.txt testing-agent-id
 vm_cmd journalctl --after-cursor "'$cursor'" -u rpm-ostreed -o json | jq -r '.AGENT_SD_UNIT//""' > agent_sd_unit.txt
-assert_file_has_content agent_sd_unit.txt sshd.service
+assert_file_has_content agent_sd_unit.txt session-1.scope
+vm_cmd "systemd-inhibit --what=shutdown --mode=block sh -c 'while ! test -f /run/wakeup; do sleep 0.1; done'" &
+if vm_rpmostree finalize-deployment "${commit}" 2>err.txt; then
+  assert_not_reached "finalized with inhibitor lock in block mode present"
+fi
+assert_file_has_content err.txt 'Reboot blocked'
+vm_cmd test -f /run/ostree/staged-deployment-locked # Make sure that staged deployment is still locked.
+vm_cmd touch /run/wakeup
+sleep 0.1 # Wait a bit for the process holding the lock to exit.
 vm_reboot_cmd rpm-ostree finalize-deployment "${commit}"
 assert_streq "$(vm_get_booted_csum)" "${commit}"
 vm_assert_journal_has_content $cursor "Finalized deployment; rebooting into ${commit}"
@@ -364,7 +372,7 @@ vm_cmd rpm-ostree deploy \'\' \
        --register-driver=OtherTestDriver --bypass-driver
 # Make sure OtherTestDriver's systemd unit will be the same as the commandline's
 vm_cmd rpm-ostree status -v > verbose_status.txt
-assert_file_has_content verbose_status.txt 'AutomaticUpdatesDriver: OtherTestDriver (sshd.service)'
+assert_file_has_content verbose_status.txt 'AutomaticUpdatesDriver: OtherTestDriver (session-1.scope)'
 vm_rpmostree upgrade 2>err.txt
 assert_not_file_has_content err.txt 'Updates and deployments are driven by OtherTestDriver'
 vm_rpmostree cleanup -p