Daniel Shahaf <d...@daniel.shahaf.name> writes:
> This fixes the race I mentioned, but I think we have another problem
> here: signum_cancelled is accessed by the signal handler so it must be
> of type 'static volatile sig_atomic_t' (C89 ยง4.7.1.1)... but I don't
> think anything guarantees that signal numbers are representable as
> a sig_atomic_t. On Linux/amd64 and FreeBSD they are, but that need not
> be the case everywhere.
>
> If we can't assume sig_atomic_t is at least as large as an int, I think
> we have to use the following roundabout method:
I did something similar in r1729422.
This code keeps growing and I'm thinking of moving both the signal
handler and cancellation handler to libsvn_subr. We need some storage
for the volatiles and using pool memory implies a limited lifetime that
interacts badly with the signal handlers so I'm thinking of using static
storage in the library. Something like:
/* Setup signal handlers and return a cancellation handler. */
svn_cancel_func_t svn_cmdline__setup_cancellation_handler();
/* Return a signal that triggered cancellation or zero if no such
signal. */
int svn_cmdline__get_cancelled_signum();
and the application would do:
int main()
{
apr_pool_t *pool;
...
SVN_ERR(svn_client_create_context2(&ctx, ..., pool));
...
ctx->cancel_func = svn_cmdline__setup_cancellation_handler();
...
svn_pool_destroy(pool);
...
#ifndef WIN32
{
int signum = svn_cmdline__get_cancelled_signum();
if (signum)
kill(getpid(), signum);
}
#endif
return exit_code;
}
--
Philip Martin
WANdisco
