Re: [PATCH] Correctly initialize 'installed_handlers'

From: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Date: May 8, 2020, 08:33 UTC
Message-ID: <20200508083340.GA36538@Carlos-MBP>
In-Reply-To: <pull.630.git.1588921514146.gitgitgadget@gmail.com>

On Fri, May 08, 2020 at 07:05:13AM +0000, Force Charlie via GitGitGadget wrote:

> From: Force Charlie <charlieio@outlook.com>
> 
> Because static variables are not initialized properly,

what do you mean by "properly"?, all static variables are set to 0; that is a warranty of the language (all the way to K&R) and any C compiler should enforce that as part of the standard.

> temporary files may not be deleted when receive-pack receives a signal.

the way this is handled would seem to indicate otherwise

if (!installed_handlers) {
                atexit(remove_tmp_objdir);
                sigchain_push_common(remove_tmp_objdir_on_signal);
                installed_handlers++;
}

there is no explicit locking and so there might be a thread race condition, but the code below wouldn't make a difference in that case.

could you elaborate more on how to reproduce the problem?, I suspect that if there was a problem then suppressing whatever signal that was triggered before sigchain_push_common might help, but the window is too short to be a likely issue.

Carlo