cli: unsubscribe permission signal from NMClient on exit

During the libnm rework, we might still emit permissions changed
signal while destructing the instance. That triggers an assertion.

Backtrace, with a different libnm:

  #0  _g_log_abort (breakpoint=1) at ../glib/gmessages.c:554
  #1  0x00007ffff77d09b6 in g_logv (log_domain=0x7ffff7f511cd "libnm", log_level=G_LOG_LEVEL_CRITICAL, format=<optimized out>, args=args@entry=0x7fffffffcb80) at ../glib/gmessages.c:1373
  #2  0x00007ffff77d0b83 in g_log
      (log_domain=log_domain@entry=0x7ffff7f511cd "libnm", log_level=log_level@entry=G_LOG_LEVEL_CRITICAL, format=format@entry=0x7ffff78215df "%s: assertion '%s' failed")
      at ../glib/gmessages.c:1415
  #3  0x00007ffff77d137d in g_return_if_fail_warning
      (log_domain=log_domain@entry=0x7ffff7f511cd "libnm", pretty_function=pretty_function@entry=0x7ffff7f58aa0 <__func__.40223> "nm_client_get_permission_result", expression=expression@entry=0x7ffff7f54830 "NM_IS_CLIENT (client)") at ../glib/gmessages.c:2771
  #4  0x00007ffff7e9de9a in nm_client_get_permission_result (client=0x0, permission=permission@entry=NM_CLIENT_PERMISSION_ENABLE_DISABLE_NETWORK) at libnm/nm-client.c:3816
  #5  0x0000555555593ba3 in got_permissions (nmc=nmc@entry=0x55555562ec20 <nm_cli>) at clients/cli/general.c:587
  #6  0x0000555555593bcb in permission_changed (client=<optimized out>, permission=<optimized out>, result=<optimized out>, nmc=0x55555562ec20 <nm_cli>) at clients/cli/general.c:600
  #7  0x00007ffff73b1aa8 in ffi_call_unix64 () at ../src/x86/unix64.S:76
  #8  0x00007ffff73b12a4 in ffi_call (cif=cif@entry=0x7fffffffced0, fn=fn@entry=0x555555593bbf <permission_changed>, rvalue=<optimized out>, avalue=avalue@entry=0x7fffffffcde0)
      at ../src/x86/ffi64.c:525
  #9  0x00007ffff78b4746 in g_cclosure_marshal_generic_va
      (closure=<optimized out>, return_value=<optimized out>, instance=<optimized out>, args_list=<optimized out>, marshal_data=<optimized out>, n_params=<optimized out>, param_types=<optimized out>) at ../gobject/gclosure.c:1614
  #10 0x00007ffff78b3996 in _g_closure_invoke_va (closure=0x5555556f4330, return_value=0x0, instance=0x55555565a020, args=0x7fffffffd180, n_params=2, param_types=0x555555656f00)
      at ../gobject/gclosure.c:873
  #11 0x00007ffff78d0228 in g_signal_emit_valist (instance=0x55555565a020, signal_id=<optimized out>, detail=0, var_args=var_args@entry=0x7fffffffd180) at ../gobject/gsignal.c:3306
  #12 0x00007ffff78d09d3 in g_signal_emit (instance=instance@entry=0x55555565a020, signal_id=<optimized out>, detail=detail@entry=0) at ../gobject/gsignal.c:3453
  #13 0x00007ffff7e8989a in _emit_permissions_changed (self=self@entry=0x55555565a020, permissions=permissions@entry=0x555555690e40 = {...}, force_unknown=force_unknown@entry=1)
      at libnm/nm-client.c:2874
  #14 0x00007ffff7e9a0c9 in _init_release_all (self=self@entry=0x55555565a020) at libnm/nm-client.c:6092
  #15 0x00007ffff7e9bcde in dispose (object=0x55555565a020 [NMClient]) at libnm/nm-client.c:6838
  #16 0x00007ffff78b8c28 in g_object_unref (_object=<optimized out>) at ../gobject/gobject.c:3344
  #17 g_object_unref (_object=0x55555565a020) at ../gobject/gobject.c:3274
  #18 0x00005555555badcf in nmc_cleanup (nmc=0x55555562ec20 <nm_cli>) at clients/cli/nmcli.c:924
  #19 0x00005555555bbea7 in main (argc=<optimized out>, argv=0x7fffffffd498) at clients/cli/nmcli.c:987

1 files changed, 4 insertions, 1 deletions

diff --git a/clients/cli/general.c b/clients/cli/general.c
index e246d2828d..123cc5b4fc 100644
--- a/clients/cli/general.c
+++ b/clients/cli/general.c
@@ -600,6 +600,9 @@ permission_changed (NMClient *client,
 	if (got_permissions (nmc)) {
 		/* Defer the printing, so that we have a chance to process the other
 		 * permission-changed signals. */
+		g_signal_handlers_disconnect_by_func (nmc->client,
+		                                      G_CALLBACK (permission_changed),
+		                                      nmc);
 		g_idle_remove_by_data (nmc);
 		g_idle_add (print_permissions, nmc);
 	}
@@ -616,7 +619,7 @@ show_nm_permissions (NmCli *nmc)
 
 	/* The client didn't get the permissions reply yet. Subscribe to changes. */
 	g_signal_connect (nmc->client, NM_CLIENT_PERMISSION_CHANGED,
-                          G_CALLBACK (permission_changed), nmc);
+	                  G_CALLBACK (permission_changed), nmc);
 
 	if (nmc->timeout == -1)
 		nmc->timeout = 10;