Some *_free functions threw asserts when passed NULL. Now all of them
accept NULL as input and perform no action when called that way.

This gains us consistence for our free functions, and allows some
code simplifications where an explicit null check is no longer necessary.

plus some other unrelated touchups that have been sitting in my
sandbox

The big change is to add a function to display the current SSL handshake
state, and to log it everywhere reasonable.  (A failure in
SSL23_ST_CR_SRVR_HELLO_A is different from one in
SSL3_ST_CR_SESSION_TICKET_A.)

This patch also adds a new log domain for OR handshaking, so you can pull out
all the handshake log messages without having to run at debug for everything.
For example, you'd just say "log notice-err [handshake]debug-err file
tor.log".

Big thanks to nickm and arma for helping me with this!

Once we had called log_free_all(), anything that tried to log a
message (like a failed tor_assert()) would fail like this:

   1. The logging call eventually invokes the _log() function.
   2. _log() calls tor_mutex_lock(log_mutex).
   3. tor_mutex_lock(m) calls tor_assert(m).
   4. Since we freed the log_mutex, tor_assert() fails, and tries to
      log its failure.
   5. GOTO 1.

Now we allocate the mutex statically, and never destroy it on
shutdown.

Bugfix on 0.2.0.16-alpha, which introduced the log mutex.

This bug was found by Matt Edman.

This patch adds a new compat_libevent.[ch] set of files, and moves our
Libevent compatibility and utilitity functions there.  We build them
into a separate .a so that nothing else in src/commmon depends on
Libevent (partially fixing bug 507).

Also, do not use our own built-in evdns copy when we have Libevent
2.0, whose evdns is finally good enough (thus fixing Bug 920).

svn:r18258

The subversion $Id$ fields made every commit force a rebuild of
whatever file got committed.  They were not actually useful for
telling the version of Tor files in the wild.

svn:r17867

svn:r17827

svn:r17741

svn:r17739

svn:r17734

One log.c XXX021 was a misunderstanding.  Also, clip log messages passed to syslog to their maximum length when there is a maximum.

svn:r17688

svn:r17662

Change logging code to use fds instead of stdio.  Fixes bug 861, and probably makes logging slightly faster.  Not a backport candidate: bug 861 is too obscure and harmless.

svn:r17456

Update _log_global_min_severity after switch_logs_debug(), so that USR2 will work again.  Bugfix on 0.1.2.8-beta.  Spotted by Geoff Down.

svn:r17317

svn:r16941

svn:r16775

New --hush command-line option similar to --quiet.  While --quiet disables all
logging to the console on startup, --hush limits the output to messages of
warning and error severity.


svn:r14222

 Free some static hashtables and the log mutex on exit. Backport candidate.


svn:r14212

svn:r14203

svn:r14202

 Fix a couple of bugs in setting control log callback severity.


svn:r14065

 Refactor log domain mask code so that nobody outside of log.c has to use SEVERITY_MASK_IDX.  It is error-prone.


svn:r14016

 Fix behavior of switch_logs_debug() in trunk.  Fixes bug 626. Bugfix on r13875.


svn:r14015

Assert that severity in logv() is sane.  Interesting effects otherwise (It is being used as an array index)


svn:r14006

 Make some assert()s into tor_assert()s.  Make some tor_assert()s called from logging into assert()s, and document why.


svn:r13977

 Change semantics of add-a-log functions to copy severity setup: that is way less error-prone.  Fix up config.c to act accordingly.


svn:r13888

 Implement domain-selection for logging.  Source is documented; needs documentation in manpage (maybe).  For now, see doxygen comment on parse_log_severity_config in log.c


svn:r13875

 Apply warnings about implicit 64-to-32 conversions; some from Sebastian Hahn; some not.


svn:r13664

svn:r13412

 Fix a bunch of DOCDOC items; document the --quiet flag; refactor a couple of XXXX020 items.


svn:r13405

 Fix bug 575: protect the list of logs with a mutex.  I couldn't find any appreciable change in logging performance on osx, but ymmv. You can undef USE_LOG_MUTEX to see if stuff gets faster for you.


svn:r13019

svn:r12786

svn:r10837

 Note that the fix for bug 222 should technically be turned into a real fix, not a kludge, one of these days.


svn:r10397

 An even better workaround for the probably-already-fixed bug 222.


svn:r10395

 Resolve all but 3 DOCDOCs.


svn:r10393