423 Commits

Author SHA1 Message Date
Philip Withnall
ca4dace62b gmain: Clarify thread safety of some common GSource functions
See https://stackoverflow.com/q/58555626/2931197.

Signed-off-by: Philip Withnall <withnall@endlessm.com>
2019-10-25 12:13:31 +01:00
Philip Withnall
d9b30d47a6 gmain: Remove some redundant casts
These were introducing strict aliasing warnings. Remove them (in line
with other uses of `g_once_init_leave()`).

Signed-off-by: Philip Withnall <withnall@endlessm.com>
2019-10-07 16:29:26 +01:00
Thomas Haller
39dd2be538 gmain: use atomic operation instead of GMutex to access g_main_context_default()
I think it is wasteful to use a mutex every time the default main context
is accessed. Especially, as the default main context is used all the
time.
2019-10-07 13:22:30 +00:00
Philip Withnall
18a232be89 glib: Various minor scan-build fixes
These squash various warnings from `scan-build`. None of them are
legitimate bugs, but some of them do improve code readability a bit.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

Helps: #1767
2019-09-05 13:51:27 +01:00
Philip Withnall
14b087ea18 gmain.c: Fix comment about Y2038 safety of g_get_real_time()
This comment was correct until commit adf1f98f62, when the `GTimeVal`
which the result was put into (introducing the Y2038-unsafety) was
dropped.

The adjustment and scaling of the `FILETIME` should not make it
Y2038-unsafe: the maximum `FILETIME` is 2^64-1. Subtracting the epoch
adjustment and dividing by 10 gives the timestamp 1833029933770955161,
which is in June 58086408216 (at just after 3am UTC). I think that’s
enough time to be going on with.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

Helps: #1438
2019-07-29 12:27:29 +01:00
Philip Withnall
ec0cc39de0 gmain: Add deprecation ignore guards around other GTimeVal usage
Signed-off-by: Philip Withnall <withnall@endlessm.com>

Helps: #1438
2019-07-29 12:27:29 +01:00
Philip Withnall
fe760ba442 gmain: Swap implementations of g_get_current_time() + g_get_real_time()
The former is now deprecated, so it makes sense to base its
implementation on the latter, rather than the other way around.

This introduces no functional changes.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

Helps: #1438
2019-07-29 12:27:29 +01:00
Philip Withnall
626b6f5ea7 gmain: Deprecate g_get_current_time() because it uses GTimeVal
GTimeVal is not year-2038-safe.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

Helps: #1438
2019-07-29 12:27:29 +01:00
David Emett
ca47f3dfd5 gmain: Fix g_main_context_prepare priority annotation 2019-06-29 14:13:16 +01:00
Philip Withnall
71973c722a gmain: Clarify that g_source_destroy() doesn’t drop a reference
This always confuses people.

Signed-off-by: Philip Withnall <withnall@endlessm.com>
2019-06-07 11:26:47 +01:00
Sebastian Dröge
0f056ebea3 Use atomic reference counting for GSource
If attached to a context already it would use a mutex instead but at
least before that the reference counting is not thread-safe currently.
2019-05-28 18:46:18 +03:00
Philip Withnall
38de3e9dc3 docs: Use ‘look up’ as a verb, rather than the noun ‘lookup’
Another niggle fixed.

Signed-off-by: Philip Withnall <withnall@endlessm.com>
2019-04-26 12:12:31 +01:00
Emmanuel Fleury
81a4698c45 Fixing various warnings in glib/gmain.c
glib/gmain.c:480:1: error: missing initializer for field ‘closure_callback’ of ‘GSourceFuncs’ {aka ‘struct _GSourceFuncs’} [-Werror=missing-field-initializers]
 };
 ^
In file included from glib/giochannel.h:33,
                 from glib/glib.h:54,
                 from glib/glib-unix.h:33,
                 from glib/gmain.c:50:
glib/gmain.h:262:19: note: ‘closure_callback’ declared here
   GSourceFunc     closure_callback;
                   ^~~~~~~~~~~~~~~~
glib/gmain.c:491:1: error: missing initializer for field ‘closure_callback’ of ‘GSourceFuncs’ {aka ‘struct _GSourceFuncs’} [-Werror=missing-field-initializers]
 };
 ^
In file included from glib/giochannel.h:33,
                 from glib/glib.h:54,
                 from glib/glib-unix.h:33,
                 from glib/gmain.c:50:
glib/gmain.h:262:19: note: ‘closure_callback’ declared here
   GSourceFunc     closure_callback;
                   ^~~~~~~~~~~~~~~~
glib/gmain.c:499:1: error: missing initializer for field ‘closure_callback’ of ‘GSourceFuncs’ {aka ‘struct _GSourceFuncs’} [-Werror=missing-field-initializers]
 };
 ^
In file included from glib/giochannel.h:33,
                 from glib/glib.h:54,
                 from glib/glib-unix.h:33,
                 from glib/gmain.c:50:
glib/gmain.h:262:19: note: ‘closure_callback’ declared here
   GSourceFunc     closure_callback;
                   ^~~~~~~~~~~~~~~~
glib/gmain.c:507:1: error: missing initializer for field ‘closure_callback’ of ‘GSourceFuncs’ {aka ‘struct _GSourceFuncs’} [-Werror=missing-field-initializers]
 };
 ^
In file included from glib/giochannel.h:33,
                 from glib/glib.h:54,
                 from glib/glib-unix.h:33,
                 from glib/gmain.c:50:
glib/gmain.h:262:19: note: ‘closure_callback’ declared here
   GSourceFunc     closure_callback;
                   ^~~~~~~~~~~~~~~~
glib/gmain.c: In function ‘g_source_set_callback_indirect’:
glib/gmain.c:1615:68: error: suggest braces around empty body in an ‘if’ statement [-Werror=empty-body]
                                               callback_funcs->get));
                                                                    ^
2019-03-15 21:30:22 +01:00
Tomasz Miąsko
a3060bc84f gmain: Synchronize access to is_running flag of GMainLoop
Synchronize access to is_running field of GMainLoop to ensure that
g_main_loop_is_running is thread safe.
2019-02-22 18:08:34 +01:00
Philip Withnall
f6caeb6d1a gthread: Add g_private_set_alloc0() internal convenience API
This is a wrapper around g_private_set() which allocates the desired
amount of memory for the caller and calls g_private_set() on it.

This is intended to make it easier to suppress Valgrind warnings about
leaked memory, since g_private_set() is typically used to make one-time
per-thread allocations. We can now just add a blanket suppression rule
for any allocations inside g_private_set_alloc0().

Signed-off-by: Philip Withnall <withnall@endlessm.com>
2019-01-07 18:54:17 +00:00
Will Thompson
cdc2dd8eb1
gmain: clamp over-large timeouts
g_main_context_prepare() needs to calculate the timeout to pass to
poll(), expressed in milliseconds as a gint.  But since the ready time
for a GSource is represented by gint64 microseconds, it's possible that
it could be more than G_MAXINT * 1000 microseconds in the future, and so
can't be represented as a gint. This conversion to a narrower signed
type is implementation-defined, but there are two possible outcomes:

* the result is >= 0, in which case poll() will time out earlier than we
  might hope (with no adverse consequences besides an unwanted wakeup)
* the result is < 0, in which case, if there are no other sources,
  poll() will block forever

This is extremely unlikely to happen in practice, but can be avoided by
clamping the gint64 value, which we know to be positive, to G_MAXINT.

Thanks to Tomasz Miąsko for pointing this out on !496.
2018-11-27 10:36:20 +00:00
Will Thompson
4ff3734ff5
g_timeout_*_seconds: don't overflow for large intervals
Previously, the `guint interval` parameter, measured in seconds, was
multiplied by 1000 and stored in another `guint` field. For intervals
greater than (G_MAXUINT / 1000) seconds, this would overflow; the
timeout would fire much sooner than intended.

Since GTimeoutSource already keeps track of whether it was created at
millisecond or second resolution, always store the passed interval
directly. We later convert the interval to microseconds, stored in a
gint64, so can move the `* 1000` to there.

The eagle-eyed reader might notice that there is no obvious guarantee
that the source's expiration time in microseconds won't overflow the
gint64, but I don't think this is a new problem. Previously, the
monotonic time would have to reach (2 ** 63 - 2 ** 32) microseconds for
this overflow to occur; now it would have to reach approximately (2 **
63 - 2 ** 42) microseconds. Both of these are 292.47 millennia to 5
significant figures.

Fixes #1600.
2018-11-26 16:04:10 +00:00
Tomasz Miąsko
dd36cf3a8b gmain: Indicate atomic fields with a comment 2018-11-13 14:57:45 +01:00
Tomasz Miąsko
969b0e00b3 gmain: Guarantee handler dispatch after receiving UNIX signal
Guarantee that user signal callback is dispatched _after_ receiving a
signal as long as the handler expresses continued interest in receiving
such a notification.

Previously if a signal has been received during user callback dispatch
but before pending flag had been cleared then the signal would be
irrevocably lost.

This is a very useful guarantee to have in cases where signals are used
to signify a need for synchronization with external resources. For
example: reloading configuration file after SIGUSR1 or retrieving a
terminal size after SIGWINCH.
2018-11-13 14:57:27 +01:00
Tomasz Miąsko
9e652f94d2 gmain: Make GUnixSignalWatchSource pending field atomic
Ensure synchronization between prepare / check /dispatch of
GUnixSignalWatchSource and UNIX signal dispatcher by making operations
on `pending` field atomic.

Issue #1312.
2018-11-13 14:57:22 +01:00
Tomasz Miąsko
d2fd53df03 gmain: Make GChildWatchSource child_exited field atomic
Ensure synchronization between prepare / check of GChildWatchsource and
UNIX signal dispatcher by making operations on `child_exited` field
atomic. Use `child_exited` as publication flag for `child_status`.

Issue #1312.
2018-11-13 14:52:50 +01:00
Tomasz Miąsko
1c8f3c67c3 gmain: Remove redundant volatile from unix_signal_refcount
Acesss to unix_signal_refcount is protected by unix_signal_lock.
2018-11-13 14:52:50 +01:00
Philip Withnall
bfe5906b40 gmain: Clarify that g_source_set_callback() is safe on attached sources
g_source_set_callback() and g_source_set_callback_indirect() are both
safe to call zero or more times on attached sources. The change in
callback will take effect the next time the source is dispatched, after
the set_callback() call returns (it could block due to locking).

https://gitlab.gnome.org/GNOME/glib/issues/827
2018-10-29 22:10:33 +00:00
Philip Withnall
0ea541171d Merge branch '903-deprecate-main-context-wait' into 'master'
gmain: Officially deprecate g_main_context_wait()

Closes #903

See merge request GNOME/glib!139
2018-06-28 16:59:39 +00:00
Philip Withnall
7a34e396ae gmain: Officially deprecate g_main_context_wait()
It’s been de-facto deprecated for a long time, due to emitting a
critical warning when used in a non-internal context. Make that official
in the documentation and with a deprecation annotation.

Split the implementation into an internal helper and an external
wrapper, so the two remaining internal uses don’t emit deprecation
warnings.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

https://gitlab.gnome.org/GNOME/glib/issues/903
2018-06-26 09:30:19 +01:00
Philip Withnall
208a6e815a gmain: Add names to various GSources constructed in GLib
For the purposes of debugging, it is quite useful for every GSource to
have a name set. Ensure that any GSource we construct inside GLib has a
name set. For GSources which are then returned to the caller, this name
can then be overridden with something even more useful by the caller.

Since this data is only used for debugging, avoid doing any allocations
for it; just use static strings.

https://gitlab.gnome.org/GNOME/glib/issues/1175
2018-06-26 09:25:39 +01:00
Philip Withnall
515dac258c gmain: Clarify documentation for g_source_get_id()
It’s good to know *which* GMainContext is used to determine the ID, and
the preconditions for calling this method.

Using wording suggested by Emmanuele Bassi <ebassi@gmail.com>.

Signed-off-by: Philip Withnall <withnall@endlessm.com>
2018-06-25 13:46:43 +01:00
Will Thompson
039fa6897b
Add G_SOURCE_FUNC cast macro which suppresses -Wcast-function-type
This is the workaround suggested by
https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wcast-function-type

This warning is not enabled by default during the GLib build, but
applications may want to opt into it.
2018-06-14 10:11:12 +01:00
Will Thompson
0f7c196c21
g_clear_handle_id: don't accept NULL clear_func
Fixes #1401.
2018-06-04 13:11:49 +01:00
Philip Withnall
9b4c50f63d all: Remove trailing newlines from g_message()/g_warning()/g_error()s
All those logging functions already add a newline to any message they
print, so there’s no need to add a trailing newline in the message
passed to them.

Signed-off-by: Philip Withnall <withnall@endlessm.com>
Reviewed-by: nobody
2018-04-27 16:46:19 +01:00
Philip Withnall
9dd8e833ef gmain: Fix some minor typos in the documentation
Signed-off-by: Philip Withnall <withnall@endlessm.com>
Reviewed-by: nobody
2018-03-26 14:48:12 +01:00
Philip Withnall
1e6803be3b gmain: Partial revert of recent wakeup changes to gmain.c
This reverts the following commits (but keeps the other recent changes
to gmain.c):
 • e4ee3079c Do not wake up main loop if change is from same thread
 • 208702404 main: Create a helper function for "owner wakeup" optimization
 • 0c0469b56 gmain: Signal wakeups if context has never been acquired as well
 • 9ba95e25b gmain: only signal GWakeup right before or during a blocking poll

Some combination of them is causing problems with LibreOffice and/or
WebKit, and the safest thing to do at the moment is revert them all
until we work out what’s going on. The previous revert (4976e8109) was
not sufficient (it fixed WebKit, but re-broken LibreOffice).

By reverting, we gain some spurious wakeups, but avoid dropping
necessary wakeups, which is presumably what’s causing problems in the
other modules.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

https://bugzilla.gnome.org/show_bug.cgi?id=761102
2018-01-18 11:31:08 +00:00
Simon McVittie
7f3bfcb891 cancellable: Don't assert if finalization races with cancellation
Commit 281e3010 narrowed the race between GCancellable::cancelled and
GCancellableSource's finalize(), but did not prevent it: there was
nothing to stop cancellation from occurring after the refcount drops
to 0, but before g_source_unref_internal() bumps it back up to 1 to
run finalize().

GCancellable cannot be expected to detect that situation, because the
only way it has to detect last-unref is finalize(), but in that
situation finalize() hasn't happened yet.

Instead of detecting last-unref, relax the precondition a little
to make it detect finalization: priv is only poisoned (set to NULL)
after the finalize() function has been called, so we can assume that
GCancellable has already seen finalize() by then.

Signed-off-by: Simon McVittie <smcv@collabora.com>
Bug: https://bugzilla.gnome.org/show_bug.cgi?id=791754
Bug-Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=884654
2018-01-05 20:42:06 +00:00
Simon McVittie
a4686b8ea1 g_source_set_ready_time: Move no-op fast-path under the lock
If we don't take the lock, then we don't have the necessary
"happens before" relationships to avoid this situation:

* source->priv->ready_time was equal to ready_time until recently
* another thread has set source->priv->ready_time to a different value
* that write hasn't become visible to this thread yet
* result: we should reset the ready_time, but we don't

Signed-off-by: Simon McVittie <smcv@collabora.com>
Bug: https://bugzilla.gnome.org/show_bug.cgi?id=791754
Bug-Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=884654
2018-01-05 20:42:06 +00:00
Philip Withnall
e91c118418 Revert "gmain: only signal GWakeup right before or during a blocking poll"
This reverts commit 9ba95e25b74adf8d62effeaf6567074ac932811c.

It is causing undiagnosed problems with WebKit and other users of GLib.
See https://bugzilla.gnome.org/show_bug.cgi?id=761102#c44 and
https://bugzilla.gnome.org/show_bug.cgi?id=761102#c46.

Reverting it until someone works out what the problem is.

https://bugzilla.gnome.org/show_bug.cgi?id=761102
2018-01-03 11:27:25 +00:00
Philip Withnall
532f1edd88 gmain: Clarify documentation of g_source_remove()
To try and prevent a repeat of
https://stackoverflow.com/q/47569812/2931197.

Signed-off-by: Philip Withnall <withnall@endlessm.com>
Reviewed-by: nobody
2017-12-01 10:24:36 +00:00
Michael Catanzaro
7f639fd5a0 gmain: Improve documentation of GSourceFuncs
We should more clearly indicate that a source ready time will result in
a source being dispatched even if prepare and check never return TRUE.

https://bugzilla.gnome.org/show_bug.cgi?id=790948
2017-11-29 13:20:40 -06:00
Philip Withnall
90dd9ff363 gmain: Unref GSourceCallbackFuncs _before_ finalising GSource
Rather than unreffing them _after_ finalising the GSource and freeing
its struct. This fixes the case where the GSourceCallbackFuncs data
contains a pointer to the GSource, and the unref() function operates on
that pointer, e.g. by calling g_source_destroy(). This happens when
using g_source_set_dummy_callback() on a GSource, as the generated
GClosure needs to destroy the GSource when it is invalidated, which
could happen (at latest) when the GSourceCallbackFuncs.unref() function
is called during finalisation of the GSource.

By moving the GSourceCallbackFuncs.unref() invocation higher up in
g_source_unref_internal(), it becomes re-entrancy-safe for GSource
methods.

https://bugzilla.gnome.org/show_bug.cgi?id=692034
2017-11-28 14:49:26 +00:00
Philip Withnall
9297a596d6 gmain: Mark some ref_count variables as volatile
To make it more obvious they should exclusively be accessed with atomic
functions.

https://bugzilla.gnome.org/show_bug.cgi?id=737677
2017-11-28 14:08:59 +00:00
Philip Withnall
d73f8eec48 gmain: Make GSourceCallback thread-safe
Otherwise there is a race in finalising the GSourceCallback if one
thread is finishing off a g_main_dispatch() while another thread is
destroying the GSource which owns the GSourceCallback.

A helgrind log:

==21707== Possible data race during write of size 4 at 0x54EACB0 by
thread #12
==21707== Locks held: none
==21707==    at 0x4ECC174: g_source_callback_unref (gmain.c:1528)
==21707==    by 0x4ECD953: g_main_dispatch (gmain.c:3081)
==21707==    by 0x4ECE667: g_main_context_dispatch (gmain.c:3673)
==21707==    by 0x4ECE859: g_main_context_iterate (gmain.c:3744)
==21707==    by 0x4ECEC7F: g_main_loop_run (gmain.c:3938)
==21707==    by 0x41C197: some_thread (some-code.c:224)
==21707==
==21707== This conflicts with a previous write of size 4 by thread #5
==21707== Locks held: 1, at address 0x54CF320
==21707==    at 0x4ECC174: g_source_callback_unref (gmain.c:1528)
==21707==    by 0x4ECB86F: g_source_destroy_internal (gmain.c:1178)
==21707==    by 0x4ECB9D4: g_source_destroy (gmain.c:1227)
==21707==    by 0x41CF09: some_other_thread (some-other-code.c:410)

https://bugzilla.gnome.org/show_bug.cgi?id=737677
2017-11-28 14:08:58 +00:00
Stefan Sauer
2812219adb docs: add missing '*' chars at start of doc-comments 2017-11-12 16:36:16 +01:00
Cosimo Cecchi
5ebd8f6e88 gmain: add g_clear_handle_id API
It's a very common pattern to see code that looks like this in
dispose() or finalize() implementations:

if (priv->source_id > 0)
  {
    g_source_remove (priv->source_id);
    priv->source_id = 0;
  }

This API allows to accomplish the same goal with a single line:

g_clear_handle_id (&priv->source_id, (GClearHandleFunc) g_source_remove);

Thanks to Emmanuele Bassi <ebassi@gnome.org> for making the patch
generic.

https://bugzilla.gnome.org/show_bug.cgi?id=788489
2017-11-07 08:28:45 -08:00
Simon McVittie
6e480634c6 g_child_watch_source_new: Document restrictions for POSIX platforms
The warnings issued when dealing with waitpid() raising ECHILD are
somewhat misleading: there are lots of reasons why waitpid() might
fail in this way, and we can't tell which one has happened.
In particular, passing a non-child or a non-pid, waiting for the same
pid elsewhere, or creating a duplicate watch for the same pid would
all fail in the same way.

Consolidate the restrictions into one place, and change all the other
places they were (or should have been!) mentioned to point to
that one place.

Signed-off-by: Simon McVittie <smcv@collabora.com>
Reviewed-by: Philip Withnall <withnall@endlessm.com>
Bug: https://bugzilla.gnome.org/show_bug.cgi?id=723743
2017-10-12 12:22:27 +01:00
Robert Ancell
db2ae64636 Fix comment/docs grammar: incase -> in case 2017-09-15 13:50:41 +12:00
INSUN PYO
61cb8b232b GMainLoop: match of parameter pair of LOCK_CONTEXT/UNLOCK_CONTEXT
There is no reason to use source->context as as parameter of UNLOCK_CONTEXT.
To avoid confusion, change to the parameter used in LOCK_CONTEXT.

https://bugzilla.gnome.org/show_bug.cgi?id=787146
2017-09-08 15:57:59 +01:00
Philip Withnall
5cddde1fb2 Consistently save errno immediately after the operation setting it
Prevent the situation where errno is set by function A, then function B
is called (which is typically _(), but could be anything else) and it
overwrites errno, then errno is checked by the caller.

errno is a horrific API, and we need to be careful to save its value as
soon as a function call (which might set it) returns. i.e. Follow the
pattern:
  int errsv, ret;
  ret = some_call_which_might_set_errno ();
  errsv = errno;

  if (ret < 0)
    puts (strerror (errsv));

This patch implements that pattern throughout GLib. There might be a few
places in the test code which still use errno directly. They should be
ported as necessary. It doesn’t modify all the call sites like this:
  if (some_call_which_might_set_errno () && errno == ESOMETHING)
since the refactoring involved is probably more harmful than beneficial
there. It does, however, refactor other call sites regardless of whether
they were originally buggy.

https://bugzilla.gnome.org/show_bug.cgi?id=785577
2017-08-03 10:21:13 +01:00
Руслан Ижбулатов
c4b5702e08 Use %lu format for DWORD 2017-07-12 19:46:07 +00:00
Ignacio Casal Quinteiro
e4e83bff72 win32: port monotonic times to use QPC
This provides a high precision monotonic time and
the concerns that we had are no longer true
on new versions of Windows (7+).

https://bugzilla.gnome.org/show_bug.cgi?id=783340
2017-06-02 18:11:11 +02:00
Руслан Ижбулатов
b4ee4628d9 GetTickCount64 is a __stdcall function
https://bugzilla.gnome.org/show_bug.cgi?id=781301
2017-06-01 11:00:29 +00:00
Sébastien Wilmet
f9faac7661 glib/: LGPLv2+ -> LGPLv2.1+
All glib/*.{c,h} files have been processed, as well as gtester-report.

12 of those files are not licensed under LGPL:

	gbsearcharray.h
	gconstructor.h
	glibintl.h
	gmirroringtable.h
	gscripttable.h
	gtranslit-data.h
	gunibreak.h
	gunichartables.h
	gunicomp.h
	gunidecomp.h
	valgrind.h
	win_iconv.c

Some of them are generated files, some are licensed under a BSD-style
license and win_iconv.c is in the public domain.

Sub-directories inside glib/:

	deprecated/: processed in a previous commit
	glib-mirroring-tab/: already LGPLv2.1+
	gnulib/: not modified, the code is copied from gnulib
	libcharset/: a copy
	pcre/: a copy
	tests/: processed in a previous commit

https://bugzilla.gnome.org/show_bug.cgi?id=776504
2017-05-24 11:58:19 +02:00