Nick Mathewson [Wed, 7 Dec 2011 16:49:52 +0000 (11:49 -0500)]
Bypass event_add when using event_base_once() for a 0-sec timeout
Some people use event_base_once(EV_TIMEOUT) to make a callback get
called "immediately". But this is pretty roundabout: it uses the
timeout heap to immediately put the event onto the active queue, when
it could just use event_active. Additionally, it can lead to
surprising re-ordering behavior.
This patch changes event_base_once so it bypasses event_add() and
called event_active() directly on a pure-timeout event with an empty
timeout.
Nick Mathewson [Mon, 5 Dec 2011 20:02:27 +0000 (15:02 -0500)]
Be absolutely sure to clear pncalls before leaving event_signal_closure
I thought we'd fixed the cases where this could come up, but
apparently having an event_base_break() happen while processing
signal events could get us in trouble.
Found by Remi Gacogne. Sourceforge issue 3451433 .
Mark Ellzey [Thu, 17 Nov 2011 16:59:41 +0000 (11:59 -0500)]
Avoid spinning on OpenSSL reads
Previously, if some sender were generating data to read on an
OpenSSL connection as fast as we could process it, we could easily
wind up looping on an openssl do_read operation without ever
considering other sockets.
The difference between this and the original method in
consider_reading() is that it only loops for a single completed
*frame* instead of looping until fd is drained or an error condition
was triggered.
Mark Ellzey [Mon, 14 Nov 2011 15:24:07 +0000 (10:24 -0500)]
Avoid potential SSL read spinlocks
OpenSSL bufferevents with deferred callbacks enabled under high load will
spinlock in the function consider_reading(). This loop continues until all
data has been read.
Because of this condition; openssl bufferevents will never return back into
event_base_loop() until SSL_read has determined data is no longer ready.
As of yet I have not found a reason why this while loop exists, so this patch
just swaps out while for if.
If needed I can write same code which would trigger this effect; optionally
libevhtp has a test.c program which can be run with the following flags:
The return data will include the number of times the readcb got data and the
length of that read.
Without this patch, you are likely to see a small amount of "bytes read....",
otherwise the "bytes read..." return data should show much more reasonable
numbers.
Samy Al Bahra [Mon, 24 Oct 2011 01:31:55 +0000 (01:31 +0000)]
evhttp: Add evhttp_foreach_bound_socket.
Applies the function specified in the first argument to all
evhttp_bound_sockets associated with a struct evhttp. The user
must not attempt to free or remove any connections, sockets or
listeners in the callback function.
Abel Mathew [Fri, 21 Oct 2011 19:53:32 +0000 (19:53 +0000)]
New event_base_update_cache_time() to set cached_tv to current time
This function is particularly useful for selectively increasing
the accuracy of the cached time value in 'base' during callbacks
that take a long time to execute.
This function has no effect if the base is currently not in its
event loop or if timeval caching is disabled via EVENT_BASE_FLAG_NO_CACHE_TIME.
Mansour Moufid [Fri, 14 Oct 2011 21:16:03 +0000 (17:16 -0400)]
Add argument checks to some memory functions in `event.c'.
Add a zero check to the function `event_mm_malloc_',
i.e. simply return NULL if the sz argument is zero.
On failure, set errno to ENOMEM and return NULL.
Add a zero check to the function `event_mm_calloc_',
i.e. simply return NULL if either argument is zero.
Also add an unsigned integer multiplication check, and if an integer
overflow would occur, set errno to ENOMEM and return NULL.
On failure, set errno to ENOMEM and return NULL.
Add a NULL check to the function `event_mm_strdup_',
i.e. set errno to EINVAL and return NULL.
Also add an unsigned integer addition check, and if an integer
overflow would occur, set errno to ENOMEM and return NULL.
If a memory allocation error occurs, again set errno to ENOMEM
and return NULL.
Leonid Evdokimov [Wed, 19 Oct 2011 18:38:37 +0000 (22:38 +0400)]
Empty DNS reply with OK status is another way to say NODATA.
Sometimes DNS reply has nothing but query section. It does not look like
error, so it should be treated as NODATA with TTL=0 as soon as there is
no SOA record to deduce negative TTL from.
Nick Mathewson [Thu, 6 Oct 2011 22:02:22 +0000 (18:02 -0400)]
Make evbuffer_file_segment_types adaptable
Instead of having a file segment born as one type and stay that way
forever, let them start out unmapped, but map themselves as needed
if they need to get written out on a non-drains_to_fd evbuffer.
Nick Mathewson [Thu, 29 Sep 2011 13:30:04 +0000 (09:30 -0400)]
Prefer mmap to sendfile unless a DRAINS_TO_FD flag is set. Allows add_file to work with SSL.
The sendfile() implementation for evbuffer_add_file is potentially more
efficient, but it has a problem: you can only use it to send bytes over
a socket using sendfile(). If you are writing bytes via SSL_send() or
via a filter, or if you need to be able to inspect your buffer, it
doesn't work.
As an easy fix, this patch disables the sendfile-based implementation of
evbuffer_add_file on an evbuffer unless the user sets a new
EVBUFFER_FLAG_DRAINS_TO_FD flag on that evbuffer, indicating that the
evbuffer will not be inspected, but only written out via
evbuffer_write(), evbuffer_write_atmost(), or drained with stuff like
evbuffer_drain() or evbuffer_add_buffer(). This flag is off by
default, except for evbuffers used for output on bufferevent_socket.
In the future, it could be interesting to make a best-effort file
segment implementation that tries to send via sendfile, but mmaps on
demand. That's too much complexity for a stable release series, though.
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