Since 0.2.3.1-alpha, we've supported the Linux extensions to socket(),
open(), socketpair(), and accept() that enable us to create an fd and
make it close-on-exec with a single syscall. This not only saves us a
syscall (big deal), but makes us less vulnerable to race conditions
where we open a socket and then exec before we can make it
close-on-exec.
But these extensions are not supported on all Linuxes: They were added
between 2.6.23 or so and 2.6.28 or so. If you were to build your Tor
against a recent Linux's kernel headers, and then run it with a older
kernel, you would find yourselve unable to open sockets. Ouch!
The solution here is that, when one of these syscalls fails with
EINVAL, we should try again in the portable way. This adds an extra
syscall in the case where we built with new headers and are running
with old ones, but it will at least allow Tor to work.
Fixes bug 5112; bugfix on 0.2.3.1-alpha.
There is a facility (not used now in Tor) to avoid storing the hash
of a given type if it is a fast-to-calculate hash.
There are also a few ancient-openbsd compilation issues fixed here.
The fact that Tor says INLINE while Libevent says inline remains
unaddressed.
The big change here is a patch (first added to Libevent by Ed Day)
to make sure that the CreateProcess forked-test trick works even
when the main test program is invoked without its .exe suffix.
The invariant is: unconfigured_proxies_n is exactly the number of
managed_proxy_t not in state PT_PROTO_COMPLETED.
To maintain this, we need to stop overloading unconfigured_proxies_n
to also count managed_proxy_t items that are in PT_PROTO_COMPLETED but
which might need relaunching. To make it so we can detect those, we
introduce another variable.
This commit also adds a function to assert that we haven't broken the
invariant.
Fix for bug 5084; bugfix on 0.2.3.6-alpha, I think.
In some cases, we solve this by doing a SMARTLIST_DEL_CURRENT before
calling managed_proxy_destroy. But for a trickier one, we just make a
copy of the list before iterating over it, so that changes to the
manage proxy list don't hurt our iteration.
This could be related to bug 5084.
Previously we'd been using "we have clock_gettime()" as a proxy for
"we need -lrt to link a static libevent". But that's not really
accurate: we should only add -lrt if searching for clock_gettime
function adds -lrt to our libraries.
