tree ff226d6d1aca36c08fb0239feba162c4e5865b57
parent 68e41281e845f4df0201390f475ec3ebd9eb55cc
author Pedro Alves <pedro@palves.net> 1623708043 +0100
committer Pedro Alves <pedro@palves.net> 1623754811 +0100

scoped_ignore_signal: Use sigprocmask+sigtimedwait instead of signal

The problem with using signal(...) to temporarily ignore a signal, is
that that changes the the signal disposition for the whole process.
If multiple threads do it at the same time, you have a race.

Fix this by using sigprocmask + sigtimedwait to implement the ignoring
instead, if available, which I think probably means everywhere except
Windows nowadays.  This way, we only change the signal mask for the
current thread, so there's no race.

Change-Id: Idfe3fb08327ef8cae926f3de9ee81c56a83b1738

gdbsupport/ChangeLog:
yyyy-mm-dd  Pedro Alves  <pedro@palves.net>

	* scoped_ignore_signal.h
	(scoped_ignore_signal::scoped_ignore_signal)
	[HAVE_SIGPROCMASK]: Use sigprocmask to block the signal instead of
	changing the signal disposition for the whole process.
	(scoped_ignore_signal::~scoped_ignore_signal) [HAVE_SIGPROCMASK]:
	Use sigtimedwait and sigprocmask to flush and unblock the signal.