TerminalControllingProcess: don't use qWarning in the child process

qWarning() and all of QMessageLogger will get to qFormatLogMessage(),
which locks a mutex. Additionally, qWarning may call a number of
different backends that, in turn, may have mutexes of their own. Locking
mutexes in child processes between fork() and execve() is a big no-no:
it may have been locked by another thread before fork(), so it's still
locked in the child process and will never get unlocked. Result:
deadlock.

Plus, qWarning reacts to QT_FATAL_WARNINGS, which I guess was not
intended for this class.

So just use a plain perror(), which is guaranteed by POSIX to be
"MT-Safe race:stderr".

Change-Id: I4e559af2a9a1455ab770fffd15f4a37a3fd113ca
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

0 files changed, 0 insertions, 0 deletions