Note that D-Bus is fundamentally asynchronous. Doing blocking calls
on top of D-Bus is odd, especially for libnm's NMClient. That is because
NMClient essentially is a client-side cache of the objects from the D-Bus
interface. This cache should be filled exclusively by (asynchronous) D-Bus
events (PropertiesChanged). So, making a blocking D-Bus call means to wait
for a response and return it, while queuing all messages that are received
in the meantime.
Basically there are three ways how a synchronous API on NMClient could behave:
1) the call just calls g_dbus_connection_call_sync(). This means
that libnm sends a D-Bus request via GDBusConnection, and blockingly
waits for the response. All D-Bus messages that get received in the
meantime are queued in the GMainContext that belongs to NMClient.
That means, none of these D-Bus events are processed until we
iterate the GMainContext after the call returns. The effect is,
that NMClient (and all cached objects in there) are unaffected by
the D-Bus request.
Most of the synchronous API calls in libnm are of this kind.
The problem is that the strict ordering of D-Bus events gets
violated.
For some API this is not an immediate problem. Take for example
nm_device_wifi_request_scan(). The call merely blockingly tells
NetworkManager to start scanning, but since NetworkManager's D-Bus
API does not directly expose any state that tells whether we are
currently scanning, this out of order processing of the D-Bus
request is a small issue.
The problem is more obvious for nm_client_networking_set_enabled().
After calling it, NM_CLIENT_NETWORKING_ENABLED is still unaffected
and unchanged, because the PropertiesChanged signal from D-Bus
is not yet processed.
This means, while you make such a blocking call, NMClient's state
does not change. But usually you perform the synchronous call
to change some state. In this form, the blocking call is not useful,
because NMClient only changes the state after iterating the GMainContext,
and not after the blocking call returns.
2) like 1), but after making the blocking g_dbus_connection_call_sync(),
update the NMClient cache artificially. This is what
nm_manager_check_connectivity() does, to "fix" bgo#784629.
This also has the problem of out-of-order events, but it kinda
solves the problem of not changing the state during the blocking
call. But it does so by hacking the state of the cache. I think
this is really wrong because the state should only be updated from
the ordered stream of D-Bus messages (PropertiesChanged signal and
similar). When libnm decides to modify the state, there may be already
D-Bus messages queued that affect this very state.
3) instead of calling g_dbus_connection_call_sync(), use the
asynchronous g_dbus_connection_call(). If we would use a sepaate
GMainContext for all D-Bus related calls, we could ensure that
while we block for the response, we iterate that internal main context.
This might be nice, because all events are processed in order and
after the blocking call returns, the NMClient state is up to date.
The are problems however: current blocking API does not do this,
so it's a significant change in behavior. Also, it might be
unexpected to the user that during the blocking call the entire
content of NMClient's cache might change and all pointers to the
cache might be invalidated. Also, of course NMClient would invoke
signals for all the changes that happen.
Another problem is that this would be more effort to implement
and it involves a small performance overhead for all D-Bus related
calls (because we have to serialize all events in an internal
GMainContext first and then invoke them on the caller's context).
Also, if the users wants this behavior, they could implement it themself
by running libnm in their own GMainContext. Note that libnm might
have bugs to make that really working, but that should be fixed
instead of adding such synchrnous API behavior.
Read also [1], for why blocking calls are wrong.
[1] https://smcv.pseudorandom.co.uk/2008/11/nonblocking/
So, all possible behaviors for synchronous API have severe behavioural
issues. Mark all this API as deprecated. Also, this serves the purpose of
identifying blocking D-Bus calls in libnm.
Note that "deprecated" here does not really mean that the API is going
to be removed. We don't break API. The user may:
- continue to use this API. It's deprecated, awkward and discouraged,
but if it works, by all means use it.
- use asynchronous API. That's the only sensible way to use D-Bus.
If libnm lacks a certain asynchronous counterpart, it should be
added.
- use GDBusConnection directly. There really isn't anything wrong
with D-Bus or GDBusConnection. This deprecated API is just a wrapper
around g_dbus_connection_call_sync(). You may call it directly
without feeling dirty.
---
The only other remainging API is the synchronous GInitable call for
NMClient. That is an entirely separate beast and not particularly
wrong (from an API point of view).
Note that synchronous API in NMSecretAgentOld, NMVpnPluginOld and
NMVpnServicePlugin as not deprecated here. These types are not part
of the D-Bus cache and while they have similar issues, it's less severe
because they have less state.
We no longer add these. If you use Emacs, configure it yourself.
Also, due to our "smart-tab" usage the editor anyway does a subpar
job handling our tabs. However, on the upside every user can choose
whatever tab-width he/she prefers. If "smart-tabs" are used properly
(like we do), every tab-width will work.
No manual changes, just ran commands:
F=($(git grep -l -e '-\*-'))
sed '1 { /\/\* *-\*- *[mM]ode.*\*\/$/d }' -i "${F[@]}"
sed '1,4 { /^\(#\|--\|dnl\) *-\*- [mM]ode/d }' -i "${F[@]}"
Check remaining lines with:
git grep -e '-\*-'
The ultimate purpose of this is to cleanup our files and eventually use
SPDX license identifiers. For that, first get rid of the boilerplate lines.
The D-Bus interface already has a boolean property "Unsaved".
While that is nicer too look at (in the API), adding a new flag
is very cumbersome, and also has more overhead. For example,
it requires extending the D-Bus API, all the way down to libnm.
Add a flags argument, that will allow to add future boolean
flags easier.
If an operation is cancelled through the GCancellable, then the idiom is
that the operation is always cancelled, even if it has finished
successfully. To ensure this is the case, add calls to
g_simple_async_result_set_check_cancellable everywhere.
Without this, e.g. gnome-control-center will crash when switching away
from the power panel quickly, as the NMClient creation finishes
asynchronously and g-c-c assume that G_IO_ERROR_CANCELLED is returned to
ensure it doesn't access the now invalid user_data parameter.
https://bugzilla.gnome.org/show_bug.cgi?id=794088
- only add an async version. I think sync requests are fundamentally flawed
because they mess up the order of D-Bus messages. Hence, also don't
call the function *_async(), like we do for other functions. As there
is only the async form, it doesn't have a suffix.
- Don't accept a NMConnection as @settings argument, but a GVariant.
In general, keep the libnm API closer to the D-Bus API and don't hide
the underlying function with a less powerful form. The user still can
conveniently call the function with
nm_remote_connection_update2 (connection,
nm_connection_to_dbus (NM_CONNECTION (connection),
NM_CONNECTION_SERIALIZE_ALL),
save_to_disk
? NM_SETTINGS_UPDATE2_FLAG_TO_DISK
: NM_SETTINGS_UPDATE2_FLAG_IN_MEMORY,
NULL,
cancellable,
callback,
user_data);
I believe the parts of libnm that invoke D-Bus methods, should be
close to the D-Bus API. Not like nm_remote_connection_commit_changes()
which has no corresponding D-Bus method.
We already have Update(), UpdateUnsaved() and Save(), which serve
similar purposes. We will need a form of update with another argument.
Most notably, to block autoconnect while doing the update.
Other use cases could be to prevent reapplying connection.zone and
connection.metered, to to reapply all changes.
Instead of adding a specific update function that only serves that
new use-case, add a extensible Update2() function. It can be extended
to cope with future variants of update.
GNOME Settings 3.26 is crashing every time a VPN connection changed its
state. After some digging, a debug message was put on dispose, and this
issue was found:
libnm-Message: Object 0x55555633c070 disposed
libnm-Message: Object 0x55555633c730 disposed
libnm-Message: Object 0x55555633eae0 disposed
libnm-Message: Object 0x555556340a80 disposed
Thread 1 "gnome-control-c" received signal SIGSEGV, Segmentation fault.
g_type_check_instance_cast (type_instance=type_instance@entry=0x55555633c070, iface_type=93825006537856) at /.../glib/gobject/gtype.c:4057
4057 node = lookup_type_node_I (type_instance->g_class->g_type);
(gdb) bt
NetworkManager is calling callbacks on disposed objects, which leads to
crashes in clients (e.g. GNOME Settings).
Fix this issue by disconnecting signal handlers when the objects are
disposed.
Patch originally by Georges Basile Stavracas Neto <georges.stavracas@gmail.com>
https://bugzilla.gnome.org/show_bug.cgi?id=787893
This makes it easier to install the files with proper names.
Also, it makes the makefile rules slightly simpler.
Lastly, the documentation is now generated into docs/api, which makes it
possible to get rid of the awkward relative file names in docbook.
This speeds up the initial object tree load significantly. Also, it
reduces the object management complexity by shifting the duties to
GDBusObjectManager.
The lifetime of all NMObjects is now managed by the NMClient via the
object manager. The NMClient creates the NMObjects for GDBus objects,
triggers the initialization and serves as an object registry (replaces
the nm-cache).
The ObjectManager uses the o.fd.DBus.ObjectManager API to learn of the
object creation, removal and property changes. It takes care of the
property changes so that we don't have to and lets us always see a
consistent object state. Thus at the time we learn of a new object we
already know its properties.
The NMObject unfortunately can't be made synchronously initializable as
the NMRemoteConnection's settings are not managed with standard
o.fd.DBus Properties and ObjectManager APIs and thus are not known to
the ObjectManager. Thus most of the asynchronous object property
changing code in nm-object.c is preserved. The objects notify the
properties that reference them of their initialization in from their
init_finish() methods, thus the asynchronously created objects are not
allowed to fail creation (or the dependees would wait forever). Not a
problem -- if a connection can't get its Settings, it's either invisible
or being removed (presumably we'd learn of the removal from the object
manager soon).
The NMObjects can't be created by the object manager itself, since we
can't determine the resulting object type in proxy_type() yet (we can't
tell from the name and can't access the interface list). Therefore the
GDBusObject is coupled with a NMObject later on.
Lastly, now that all the objects are managed by the object manager, the
NMRemoteSettings and NMManager go away when the daemon is stopped. The
complexity of dealing with calls to NMClient that would require any of
the resources that these objects manage (connection or device lists,
etc.) had to be moved to NMClient. The bright side is that his allows
for removal all of the daemon presence tracking from NMObject.
Relax our error checking which will allow us to try harder to
make the best out of whatever NetworkManager sends us.
Also, drop the g_warning(). First, now we really don't expect this
function to fail. And even in that case, raising a g_warning() from
the library is not very friendly to the user of libnm.
GError codes are only unique per domain, so logging the code without
also indicating the domain is not helpful. And anyway, if the error
messages are not distinctive enough to tell the whole story then we
should fix the error messages.
Based-on-patch-by: Dan Winship <danw@gnome.org>
Functions that take a GError** MUST fill it in on error. There is no
need to check whether error is NULL if the function it was passed to
had a failing return value.
Likewise, a proper GError must have a non-NULL message, so there's no
need to double-check that either.
Based-on-patch-by: Dan Winship <danw@gnome.org>
- All internal source files (except "examples", which are not internal)
should include "config.h" first. As also all internal source
files should include "nm-default.h", let "config.h" be included
by "nm-default.h" and include "nm-default.h" as first in every
source file.
We already wanted to include "nm-default.h" before other headers
because it might contains some fixes (like "nm-glib.h" compatibility)
that is required first.
- After including "nm-default.h", we optinally allow for including the
corresponding header file for the source file at hand. The idea
is to ensure that each header file is self contained.
- Don't include "config.h" or "nm-default.h" in any header file
(except "nm-sd-adapt.h"). Public headers anyway must not include
these headers, and internal headers are never included after
"nm-default.h", as of the first previous point.
- Include all internal headers with quotes instead of angle brackets.
In practice it doesn't matter, because in our public headers we must
include other headers with angle brackets. As we use our public
headers also to compile our interal source files, effectively the
result must be the same. Still do it for consistency.
- Except for <config.h> itself. Include it with angle brackets as suggested by
https://www.gnu.org/software/autoconf/manual/autoconf.html#Configuration-Headers
connection_added() can be called before init_get_settings_cb(), and we can't
complete the connection until it is visible, else it would be uninitialized.
Test case:
* have 'em1' interface
$ nmcli con add type ethernet con-name myeth ifname em1 autoconnect no
(process:9039): libnm-CRITICAL **: nm_connection_get_id: assertion 's_con != NULL' failed
Connection '(null)' ((null)) successfully added.
$ nmcli con add type ethernet con-name myeth ifname em1X autoconnect no
Connection 'myeth' (71159504-c2af-4773-8ca9-a3626aa0da33) successfully added.
https://bugzilla.gnome.org/show_bug.cgi?id=754767https://bugzilla.gnome.org/show_bug.cgi?id=754794
[lkundrak@v3.sk: This is not quite the correct fix, we shouldn't emit
NMObject:connection-added for an unfinished object. Nevertheless, let's go with
it until we have a better one. Will revert this afterwards. See linked bugs.]
The localization headers are now included via "nm-default.h".
Also fixes several places, where we wrongly included <glib/gi18n-lib.h>
instead of <glib/gi18n.h>. For example under "clients/" directory.
Rather than randomly including one or more of <glib.h>,
<glib-object.h>, and <gio/gio.h> everywhere (and forgetting to include
"nm-glib-compat.h" most of the time), rename nm-glib-compat.h to
nm-glib.h, include <gio/gio.h> from there, and then change all .c
files in NM to include "nm-glib.h" rather than including the glib
headers directly.
(Public headers files still have to include the real glib headers,
since nm-glib.h isn't installed...)
Also, remove glib includes from header files that are already
including a base object header file (which must itself already include
the glib headers).
(process:6888): GLib-GObject-WARNING **: invalid unclassed pointer in cast to 'GDBusProxy'
Program received signal SIGTRAP, Trace/breakpoint trap.
g_logv (log_domain=0x3149a3b224 "GLib-GObject", log_level=G_LOG_LEVEL_WARNING, format=<optimized out>, args=args@entry=0x7fffffffda70) at gmessages.c:1046
1046 g_private_set (&g_log_depth, GUINT_TO_POINTER (depth));
(gdb) bt
#0 0x0000003148e50c70 in g_logv (log_domain=0x3149a3b224 "GLib-GObject", log_level=G_LOG_LEVEL_WARNING, format=<optimized out>, args=args@entry=0x7fffffffda70) at gmessages.c:1046
#1 0x0000003148e50eaf in g_log (log_domain=log_domain@entry=0x3149a3b224 "GLib-GObject", log_level=log_level@entry=G_LOG_LEVEL_WARNING, format=format@entry=0x3149a42690 "invalid unclassed pointer in cast to '%s'") at gmessages.c:1079
#2 0x0000003149a34171 in g_type_check_instance_cast (type_instance=type_instance@entry=0x6fc530, iface_type=<optimized out>) at gtype.c:4030
#3 0x00007ffff7d6b016 in nmdbus_settings_connection_call_get_settings_finish (proxy=0x6fc530, out_settings=out_settings@entry=0x7fffffffdbb8, res=res@entry=0x6fe150, error=error@entry=0x0)
at nmdbus-settings-connection.c:1303
#4 0x00007ffff7ce8813 in updated_get_settings_cb (proxy=<optimized out>, result=0x6fe150, user_data=user_data@entry=0x6fc650) at nm-remote-connection.c:588
#5 0x000000314a27640d in g_simple_async_result_complete (simple=0x6fe150 [GSimpleAsyncResult]) at gsimpleasyncresult.c:763
#6 0x000000314a2df47c in reply_cb (connection=<optimized out>, res=0x6fe0e0, user_data=user_data@entry=0x6fe150) at gdbusproxy.c:2623
#7 0x000000314a27640d in g_simple_async_result_complete (simple=0x6fe0e0 [GSimpleAsyncResult]) at gsimpleasyncresult.c:763
#8 0x000000314a2d48cc in g_dbus_connection_call_done (source=<optimized out>, result=<optimized out>, user_data=user_data@entry=0x7fffec01a320) at gdbusconnection.c:5502
#9 0x000000314a27640d in g_simple_async_result_complete (simple=0x6e5f40 [GSimpleAsyncResult]) at gsimpleasyncresult.c:763
#10 0x000000314a27647c in complete_in_idle_cb (data=0x6e5f40) at gsimpleasyncresult.c:775
#11 0x0000003148e49b6b in g_main_context_dispatch (context=0x687970) at gmain.c:3064
#12 0x0000003148e49b6b in g_main_context_dispatch (context=context@entry=0x687970) at gmain.c:3663
#13 0x0000003148e49f08 in g_main_context_iterate (context=0x687970, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at gmain.c:3734
#14 0x0000003148e4a232 in g_main_loop_run (loop=0x687a80) at gmain.c:3928
#15 0x00000000004136a1 in main (argc=<optimized out>, argv=<optimized out>) at nmcli.c:632
(gdb)
Libraries need to include <gi18n-lib.h>, not <gi18n.h>, so that _()
will get defined to "dgettext (GETTEXT_DOMAIN, string)" rather than
"gettext (string)" (which will use the program's default domain, which
works fine for programs in the NetworkManager tree, but not for
external users). Likewise, we need to call bindtextdomain() so that
gettext can find the translations if the library is installed in a
different prefix from the program using it (and
bind_textdomain_codeset(), so it will know the translations are in
UTF-8 even if the locale isn't).
(The fact that no one noticed this was broken before is because the
libraries didn't really start returning useful translated strings much
until 0.9.10, and none of the out-of-tree clients have been updated to
actually show those strings to users yet.)
config.h should be included from every .c file, and it should be
included before any other include. Fix that.
(As a side effect of how I did this, this also changes us to
consistently use "config.h" rather than <config.h>. To the extent that
it matters [which is not much], quotes are more correct anyway, since
we're talking about a file in our own build tree, not a system
include.)
NMRemoteConnection used to return
NM_REMOTE_CONNECTION_ERROR_DISCONNECTED if you tried to operate on a
connection that had been disconnected from its D-Bus proxy. But this
disappeared in the gdbus port (since gdbus doesn't emit a signal when
it happens, so it's harder to notice. And it's not clear why
NMRemoteConnection did this when no other class did anyway...).
Add the missing variant in most places in the API where previously
there was either only a synchronous version or only an asynchronous
version.
There is not yet a synchronous nm_client_activate_connection(),
nm_client_add_and_activate_connection(), or
nm_remote_settings_add_connection(), because the existing async code
depends on waiting for other asynchronous events, so making them run
synchronously is slightly more complicated. But these APIs can be
added later.
Make synchronous APIs take GCancellables, and make asynchronous APIs
use GAsyncReadyCallbacks and have names ending in "_async", with
"_finish" functions to retrieve the results.
Also, make nm_client_activate_connection_finish(),
nm_client_add_and_activate_finish(), and
nm_remote_settings_add_connection_finish() be (transfer full) rather
than (transfer none), because the refcounting semantics become
slightly confusing in some edge cases otherwise.
Merge nm_remote_settings_add_connection() and
nm_remote_settings_add_connection_unsaved(), and likewise
nm_remote_connection_commit_changes() and
nm_remote_connection_commit_changes_unsaved(), by adding a boolean
flag to each saying whether to save to disk.
Port libnm-core/libnm to GDBus.
The NetworkManager daemon continues to use dbus-glib; the
previously-added connection hash/variant conversion methods are now
moved to NetworkManagerUtils (along with a few other utilities that
are now only needed by the daemon code).
In preparation for porting to GDBus, make nm_connection_to_dbus(),
etc, represent connections as GVariants of type 'a{sa{sv}}' rather
than as GHashTables-of-GHashTables-of-GValues.
This means we're constantly converting back and forth internally, but
this is just a stepping stone on the way to the full GDBus port, and
all of that code will go away again later.
Add _nm_object_class_add_interface(), for declaring that a class
implements a particular interface, and then have NMObject create the
corresponding proxies itself. (The subclass can get a copy with
_nm_object_get_proxy() if it needs it for something).
(In GDBus, creating a proxy is a heavier operation than in dbus-glib,
so we'll need to create the proxies asynchronously. Moving the
creation to NMObject makes that easier since we can do it as part
of the existing init/init_async.)
The only plausible use case for the NMObject:dbus-connection property
is for using the session bus in test programs. So just drop it and use
an environment variable to decide which bus to use instead.
On failure, nm_connection_replace_settings() would leave the
connection in an undefined state. Fix it so that either (a) the
settings are replaced and the resulting connection is valid and we
return TRUE, or (b) the connection is untouched and we return FALSE
and an error. (And add a test case for this.)
Rename nm_connection_to_hash() to nm_connection_to_dbus(), and
nm_connection_new_from_hash() to nm_connection_new_from_dbus(). In
addition to clarifying that this is specifically the D-Bus
serialization format, these names will also work better in the
GDBus-based future where the serialization format is GVariant, not
GHashTable.
Also, move NMSettingHashFlags to nm-connection.h, and rename it
NMConnectionSerializationFlags.
The fact that NMRemoteConnection has to be an NMConnection and
therefore can't be an NMObject means that it needs to reimplement bits
of NMObject functionality (and likewise NMObject needs some special
magic to deal with it). Likewise, we will need a daemon-side
equivalent of NMObject as part of the gdbus port, and we would want
NMSettingsConnection to be able to inherit from this as well.
Solve this problem by making NMConnection into an interface, and
having NMRemoteConnection and NMSettingsConnection implement it. (We
use some hacks to keep the GHashTable of NMSettings objects inside
nm-connection.c rather than having to be implemented by the
implementations.)
Since NMConnection is no longer an instantiable type, this adds
NMSimpleConnection to replace the various non-D-Bus-based uses of
NMConnection throughout the code. nm_connection_new() becomes
nm_simple_connection_new(), nm_connection_new_from_hash() becomes
nm_simple_connection_new_from_hash(), and nm_connection_duplicate()
becomes nm_simple_connection_new_clone().
NMRemoteConnection had two DBusGConnection properties
(NMRemoteConnection:bus and NMRemoteConnection:dbus-connection) and
two D-Bus path properties (NMConnection:path and
NMRemoteConnection:dbus-path). The former of each pair were the
traditional names, and the latter were added for compatibility with
NMObject.
In libnm, we can just drop NMRemoteConnection:bus, and use the
NMObject-compatible :dbus-connection name instead.
For the path properties, we need to rename either NMConnection:path or
NMObject:dbus-path. Since NMObject already has "nm_object_get_path()"
rather than "nm_object_get_dbus_path()", and it already mistakenly
referred to the property as "NMObject:path" in the gtk-docs, it seemed
to make sense to rename that one rather than the NMConnection one.
(And then, for consistency, rename "nm_object_get_connection()" to
"nm_object_get_dbus_connection()" to also match its property.)
Remove NMRemoteConnection::updated, which since 0.9.10 has been
redundant with NMConnection::changed. (We still handle the incoming
D-Bus signal, we just don't re-emit it as "updated", since the call to
nm_connection_replace_settings() already results in it emitting
"changed".)
