fish's signal handlers are now sufficiently innocuous that there should
be no reason to block signals (outside of temporarily, when creating a
thread and we need to manipulate the signal mask).
Prior to this fix, an "event" was used as both a predicate on which events
to match, and also as the event itself. Re-express these concepts
distinctly: an event is something that happened, an event_handler is the
predicate and name of the function to execute.
Prior to this fix, fish had a signal_list_t that accumulated signals.
Signals were added to an array of integers, with an overflow flag.
The event machinery would attempt to atomically "swap in" the other list.
After this fix, there is a single list of pending signal events, as an array
of atomic booleans. The signal handler sets the boolean corresponding to its
signal.
In a galaxy far, far away, event_blockage_t was intended to block only cetain
events. But it always just blocked everything. Eliminate the event block
mask.
Arch changed the version string to include the package rel, so it
looks like
systemd 241 (241.7-2-arch)
which would break our simple `string replace` and `test`.
Fixes#5689.
[ci skip]
This was treated as a glob where it was still enabled, most likely removing the "-E" option from argparse,
which caused `sudo -E` to not be parsed correctly, breaking completion.
(There was no error because the glob was used with `set`)
Fixes#5675.
[ci skip]
As it turns out, NetBSD's rand(3) is awful - it's possible that in any
given run it'll only return odd numbers, which means
while (rand() % 10)
will never stop.
Since random(3) is also standardized and works, let's use that!
This commit merges support for a new event publishing mechanism
"topic_monitor" that allow for waiting on multiple event types. It then
replaces waitpid() logic inside `process_mark_finished_children` with new
and simpler logic built around this mechanims. Lastly it migrates the
builtin and function output from processes to background threads.
Now that we use an internal process to perform builtin output, simplify the
logic around how it is performed. In particular we no longer have to be
careful about async-safe functions since we do not fork.
Also fix a bunch of comments that no longer apply.
This uses the new internal process mechanism to write output for builtins.
After this the only reason fish ever forks is to execute external processes.
This introduces "internal processes" which are backed by a pthread instead
of a normal process. Internal processes are reaped using the topic
machinery, plugging in neatly alongside the sigchld topic; this means that
process_mark_finished_children() can wait for internal and external
processes simultaneously.
Initially internal processes replace the forked process that fish uses to
write out the output of blocks and functions.
This adds an "in-process" interpretation of dup2s, allowing for fish to
output directly to the correct file descriptor without having to perform
an in-kernel dup2 sequence.
The sigchld generation expresses the idea that, if we receive a sigchld
signal, the generation will be different than when we last recorded it. A
process cannot exit before it has launched, so check the generation count
before process launch. This is an optimization that reduces failing
waitpid calls.
This is a big change to how process reaping works, reimplenting it using
topics. The idea is to simplify the logic in
process_mark_finished_children around blocking, and also prepare for
"internal processes" which do not correspond to real processes.
Before this change, fish would use waitpid() to wait for a process group,
OR would individually poll processes if the process group leader was
unreapable.
After this change, fish no longer ever calls blocking waitpid(). Instead
fish uses the topic mechanism. For each reapable process, fish checks if
it has received a SIGCHLD since last poll; if not it waits until the next
SIGCHLD, and then polls them all.
