It's redundant, which leads to impossible code like:
if (child_watch_source->using_pidfd)
{
if (child_watch_source->poll.fd >= 0)
close (child_watch_source->poll.fd);
GChildWatchSource uses waitpid(), among pidfd and GetExitCodeProcess().
It thus only works for child processes which the user must ensure to
exist and not being reaped yet. Also, the user must not kill() the PID
after the child process is reaped and must not race kill() against
waitpid(). Also, the user must not call waitpid()/kill() after the child
process is reaped.
Previously, GChildWatchSource would call waitpid() already when adding
the source (g_child_watch_source_new()) and from the worker thread
(dispatch_unix_signals_unlocked()). That is racy:
- if a child watcher is attached and did not yet fire, you cannot call
kill() on the PID without racing against the PID being reaped on the
worker thread. That would then lead to ESRCH or even worse, killing
the wrong process.
- if you g_source_destroy() the source that didn't fire yet, the user
doesn't know whether the PID was reaped in the background. Any
subsequent kill()/waitpid() may fail with ESRCH/ECHILD or even address
the wrong process.
The race is most visible on Unix without pidfd support, because then the
process gets reaped on the worker thread or during g_child_watch_source_new().
But it's also with Windows and pidfd, because we would have waited for
the process in g_child_watch_check(), where other callbacks could fire
between reaping the process status and emitting the source's callback.
Fix all that by calling waitpid() right before dispatching the callback.
Note that the prepare callback only has one caller, which pre-initializes
the timeout argument to -1. That may be an implementation detail and not
publicly promised, but it wouldn't make sense to do it any other way in
the caller.
Also, note that g_unix_signal_watch_prepare() and the UNIX branch of
g_child_watch_prepare() already relied on that.
Note that the variable source_timeout is already initialized upon
definition, at the beginning of the block.
It's easy to see, that no code changes the variable between the variable
definition, and the place where it was initialized. It was thus
unnecessary.
It's not about dropping the unnecessary code (the compiler could do that
just fine too). It's that there is the other branch of the "if/else", where
the variable is also not initialized. But the other branch also requires
that the variable is in fact initialized to -1, because prepare()
callbacks are free not to explicitly set the output value. So both
branches require the variable to be initialized to -1, but only one of
them did. This poses unnecessary questions about whether anything is
wrong. Avoid that by dropping the redundant code.
- if a child watch source has "using_pidfd", it is never linked in the
unix_child_watches list. Drop that check.
- replace the deep nested if, with an early "continue" in the loop,
if we detect there is nothing to do. It makes the code easier to
read.
Let's move the difference between the win/unix implementations closer to
where the difference is. Thereby, we easier see the two implementations
side by side. Splitting it at a higher layer makes the code harder to
read.
This is just a preparation for what comes next.
GTK lost it's '+' suffix back in 2019, according to
<https://mail.gnome.org/archives/gtk-devel-list/2019-February/msg00000.html>
This commit can be re-generated with:
git grep -l GTK+ \
| grep -v -e ^NEWS -e ^glib/tests/collate.c \
| xargs sed -i 's/GTK+/GTK/g'
Most of the changes are in comments and documentation.
Use more modern styling to the code added in the previous patch:
- split 'label: stmt; stmt;' into multiple lines
- add default: label with g_assert_not_reached() [yes, it's a bit
weird adding an assertion inside code that handles assertions, but
we should be okay since g_assertion_message_* are not public
functions and should only be used by our macros]
- use <inttypes.h> for shorter format strings
Note, however, that using uint64_t in gtestutils.h is not feasible,
since it would require adding an '#include <stdint.h>' with potential
unintended namespace pollution to older clients.
Signed-off-by: Eric Blake <eblake@redhat.com>
While x86_64 has enough precision in long double to do a round trip
from guint64 to long double and back, this is platform-specific, and
is a disservice to users trying to debug failing unit tests on other
architectures where it loses precision for g_assert_cmp{int,uint,hex}.
See also https://bugzilla.gnome.org/show_bug.cgi?id=788385 which
mentions having to add casts to specifically silence the compiler on
platforms where the precision loss occurs.
Meanwhile, g_assert_cmpuint() does an unsigned comparison, but outputs
signed values if the comparison fails, which is confusing.
Fix both issues by introducing a new g_assertion_message_cmpint()
function with a new 'u' numtype. For backwards compatibility, the
macros still call into the older g_assertion_message_cmpnum() when not
targetting 2.78, and that function still works when passed 'i' and 'x'
types even though code compiled for 2.78 and later will never invoke
it with numtype anything other than 'f'. Note that g_assert_cmpmem
can also take advantage of the new code, even though in practice,
comparison between two size_t values representing array lengths that
can actually be compiled is unlikely to have ever hit the precision
loss. The macros in signals.c test code does not have to worry about
versioning, since it is not part of the glib library proper.
Closes#2997
Signed-off-by: Eric Blake <eblake@redhat.com>
This should hopefully stop the kernel spending a lot of memory and disk
bandwidth creating coredumps for them unnecessarily, which slows down
the rest of the tests and generally wastes resources.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Fixes: #2939
This is put together through git archaeology:
```
git log -- glib/tests/assert-msg-test.c tests/assert-msg-test.c
```
The following commits were too trivial to have meaningful copyright:
- 8e59d8602ca5921d78245f5d2b405b517a5e7cf9
- 44c004c84e9080040ff4e0e90b322dda0561cf85
- 207b8cb8a50d68e207d28b59e588311a5cbd9772
- a1bee97d4f093db01dee834bf3292eabd5b13d17
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Helps: #1415
Apparently 3 hashes is too many, and as a result this line is not
displayed properly in the HTML documentation. 2 hashes seems to be
just right, as can be seen with:
$ git grep '^ \* ##' | wc -l
65
$ git grep '^ \* ###' | wc -l
1
Otherwise it might look like it would only start spawning threads when
jobs are enqueued.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Helps: #2958
If you’re only quickly looking at the API signature, it looks like
`item_free_func` will be called for all items enqueued to the thread
pool.
As it happens, it’s actually only called for the items which are still
enqueued when the thread pool is destroyed. The user’s `GFunc` is
responsible for freeing items which are successfully dequeued and
processed during the lifetime of the thread pool.
That’s a bit of a gotcha, so document it more explicitly.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
If both __NR_futex and __NR_futex_time64 are defined, g_futex_simple()
will first call futex_time64(). If that fails with ENOSYS, then
futex_time() is called instead. However, errno was not saved and
restored in this case, which would result in g_futex_simple()
returning with errno set to ENOSYS, even if futex_time() succeeded.
As with the previous commit.
The logic has to be a little contorted here to avoid leaving the context
locked after emitting the critical warning. Execution does (and should)
continue after a critical warning by default, so we should do our best
to recover.
Inspired by https://gitlab.gnome.org/GNOME/glib/-/merge_requests/3302.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
The documentation was fairly clear before, but we can make it clearer:
it’s a programming error to call `g_main_context_release()` if you have
not received a true return value from `g_main_context_acquire()` before.
Inspired by https://gitlab.gnome.org/GNOME/glib/-/merge_requests/3302.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
We need a way to initialise refcounted types placed in static storage,
or on the stack. Using proper macros avoids knowing the magic constant
used for grefcount and gatomicrefcount.
In non-perf mode, we were making only one thread to win the race to increase
the value, but since we're launching more threads anyways let's allow
more of them to have a chance to do something, to make the test more
valuable, even if it's still quick enough.
This removes the `comment` member of the GKeyFileGroup structure, which
seemed intended to distinguish comments just above a group from comments
above them, separated by one or more blank lines. Indeed:
* This does not seem to match any specification in the documentation,
where blank lines and lines starting with `#` are indiscriminately
considered comments. In particular, no distinction is made between the
comment above the first group and the comment at the beginning of the
file.
* This distinction was only half implemented, resulting in confusion
between comment above a group and comment at the end of the preceding
group.
Instead, the same logic is used for groups as for keys: the comment
above a group is simply the sequence of key-value pairs of the preceding
group where the key is null, starting from the bottom.
The addition of a blank line above groups when writing, involved in
bugs #104 and #2927, is kept, but:
* It is now added as a comment as soon as the group is added (since a
blank line is considered a comment), so that
`g_key_file_get_comment()` returns the correct result right away.
* It is always added if comments are not kept.
* Otherwise it is only added if the group is newly created (not present
in the original data), in order to really keep comments (existing and
not existing).
Closes: #104, #2927
Even though having NULL as nullptr should be the standard for newer C++
versions, it may break some headers, so let's not touch it for now.
Closes: https://gitlab.gnome.org/GNOME/glib/-/issues/2973
