Commit e5b88dc8 authored by Nick Mathewson's avatar Nick Mathewson 🐘
Browse files

Update Tor to use Libevent 2.0 APIs when available. 

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).
parent cfce7d5d

.gitignore

+1 −0
Changes for .gitignore: 1 added line, 0 removed lines.
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@@ -111,6 +111,7 @@ 
/src/common/common_sha1.i

/src/common/libor.a

/src/common/libor-crypto.a

/src/common/libor-event.a



# /src/config/

/src/config/Makefile

configure.in

+5 −1
Changes for configure.in: 5 added lines, 1 removed line.
Original line number Diff line number Diff line
@@ -273,15 +273,19 @@ save_CPPFLAGS="$CPPFLAGS" 
LIBS="-levent $TOR_LIB_WS32 $LIBS"

LDFLAGS="$TOR_LDFLAGS_libevent $LDFLAGS"

CPPFLAGS="$TOR_CPPFLAGS_libevent $CPPFLAGS"

AC_CHECK_FUNCS(event_get_version event_get_method event_set_log_callback)

AC_CHECK_FUNCS(event_get_version event_get_method event_set_log_callback evdns_set_outgoing_bind_address)

AC_CHECK_MEMBERS([struct event.min_heap_idx], , ,

[#include <event.h>

])



AC_CHECK_HEADERS(event2/event.h event2/dns.h)



LIBS="$save_LIBS"

LDFLAGS="$save_LDFLAGS"

CPPFLAGS="$save_CPPFLAGS"



AM_CONDITIONAL(USE_EXTERNAL_EVDNS, test x$ac_cv_header_event2_dns_h = xyes)



dnl ------------------------------------------------------

dnl Where do you live, openssl?  And how do we call you?

src/common/Makefile.am

+3 −2
Changes for src/common/Makefile.am: 3 added lines, 2 removed lines.
Original line number Diff line number Diff line 


noinst_LIBRARIES = libor.a libor-crypto.a

noinst_LIBRARIES = libor.a libor-crypto.a libor-event.a



EXTRA_DIST = common_sha1.i
@@ -14,8 +14,9 @@ endif 
libor_a_SOURCES = address.c log.c util.c compat.c container.c mempool.c \

	memarea.c util_codedigest.c $(libor_extra_source)

libor_crypto_a_SOURCES = crypto.c aes.c tortls.c torgzip.c

libor_event_a_SOURCES = compat_libevent.c



noinst_HEADERS = address.h log.h crypto.h test.h util.h compat.h aes.h torint.h tortls.h strlcpy.c strlcat.c torgzip.h container.h ht.h mempool.h memarea.h ciphers.inc

noinst_HEADERS = address.h log.h crypto.h test.h util.h compat.h aes.h torint.h tortls.h strlcpy.c strlcat.c torgzip.h container.h ht.h mempool.h memarea.h ciphers.inc compat_libevent.h



common_sha1.i: $(libor_SOURCES) $(libor_crypto_a_SOURCES) $(noinst_HEADERS)

	if test "@SHA1SUM@" != none; then \

src/common/compat_libevent.c

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+153 −0
Changes for src/common/compat_libevent.c: 153 added lines, 0 removed lines.
Original line number Diff line number Diff line 
/* Copyright (c) 2009, The Tor Project, Inc. */

/* See LICENSE for licensing information */



/**

 * \file compat_libevent.c

 * \brief Wrappers to handle porting between different versions of libevent.

 *

 * In an ideal world, we'd just use Libevent 2.0 from now on.  But as of June

 * 2009, Libevent 2.0 is still in alpha, and we will have old versions of

 * Libevent for the forseeable future.

 **/



#include "orconfig.h"

#include "compat_libevent.h"



#include "compat.h"

#include "util.h"

#include "log.h"



#ifdef HAVE_EVENT2_EVENT_H

#include <event2/event.h>

#else

#include <event.h>

#endif



#ifdef HAVE_EVENT_SET_LOG_CALLBACK

/** A string which, if it appears in a libevent log, should be ignored. */

static const char *suppress_msg = NULL;

/** Callback function passed to event_set_log() so we can intercept

 * log messages from libevent. */

static void

libevent_logging_callback(int severity, const char *msg)

{

  char buf[1024];

  size_t n;

  if (suppress_msg && strstr(msg, suppress_msg))

    return;

  n = strlcpy(buf, msg, sizeof(buf));

  if (n && n < sizeof(buf) && buf[n-1] == '\n') {

    buf[n-1] = '\0';

  }

  switch (severity) {

    case _EVENT_LOG_DEBUG:

      log(LOG_DEBUG, LD_NET, "Message from libevent: %s", buf);

      break;

    case _EVENT_LOG_MSG:

      log(LOG_INFO, LD_NET, "Message from libevent: %s", buf);

      break;

    case _EVENT_LOG_WARN:

      log(LOG_WARN, LD_GENERAL, "Warning from libevent: %s", buf);

      break;

    case _EVENT_LOG_ERR:

      log(LOG_ERR, LD_GENERAL, "Error from libevent: %s", buf);

      break;

    default:

      log(LOG_WARN, LD_GENERAL, "Message [%d] from libevent: %s",

          severity, buf);

      break;

  }

}

/** Set hook to intercept log messages from libevent. */

void

configure_libevent_logging(void)

{

  event_set_log_callback(libevent_logging_callback);

}

/** Ignore any libevent log message that contains <b>msg</b>. */

void

suppress_libevent_log_msg(const char *msg)

{

  suppress_msg = msg;

}

#else

void

configure_libevent_logging(void)

{

}

void

suppress_libevent_log_msg(const char *msg)

{

  (void)msg;

}

#endif



#ifndef HAVE_EVENT2_EVENT_H

/** Work-alike replacement for event_new() on pre-Libevent-2.0 systems. */

struct event *

tor_event_new(struct event_base *base, int sock, short what,

              void (*cb)(int, short, void *), void *arg)

{

  struct event *e = tor_malloc_zero(sizeof(struct event));

  event_set(e, sock, what, cb, arg);

  event_base_set(base, e);

  return e;

}

/** Work-alike replacement for evtimer_new() on pre-Libevent-2.0 systems. */

struct event *

tor_evtimer_new(struct event_base *base,

                void (*cb)(int, short, void *), void *arg)

{

  return tor_event_new(base, -1, 0, cb, arg);

}

/** Work-alike replacement for evsignal_new() on pre-Libevent-2.0 systems. */

struct event *

tor_evsignal_new(struct event_base * base, int sig,

                 void (*cb)(int, short, void *), void *arg)

{

  return tor_event_new(base, sig, EV_SIGNAL, cb, arg);

}

/** Work-alike replacement for event_free() on pre-Libevent-2.0 systems. */

void

tor_event_free(struct event *ev)

{

  event_del(ev);

  tor_free(ev);

}

#endif



/** Global event base for use by the main thread. */

struct event_base *the_event_base = NULL;



/** Initialize the Libevent library and set up the event base. */

void

tor_libevent_initialize(void)

{

  tor_assert(the_event_base == NULL);

#ifdef HAVE_EVENT2_EVENT_H

  the_event_base = event_base_new();

#else

  the_event_base = event_init();

#endif

}



/** Return the current Libevent event base that we're set up to use. */

struct event_base *

tor_libevent_get_base(void)

{

  return the_event_base;

}



/** Return the name of the Libevent backend we're using. */

const char *

tor_libevent_get_method(void)

{

#ifdef HAVE_EVENT2_EVENT_H

  return event_base_get_method(the_event_base);

#elif defined(HAVE_EVENT_GET_METHOD)

  return event_get_method();

#else

  return "<unknown>";

#endif

}

src/common/compat_libevent.h

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Changes for src/common/compat_libevent.h: 39 added lines, 0 removed lines.
Original line number Diff line number Diff line 
/* Copyright (c) 2009, The Tor Project, Inc. */

/* See LICENSE for licensing information */



#ifndef _TOR_COMPAT_LIBEVENT_H

#define _TOR_COMPAT_LIBEVENT_H



#include "orconfig.h"



#ifdef HAVE_EVENT2_EVENT_H

#include <event2/event.h>

#else

#include <event.h>

#define evutil_socket_t int

#endif



void configure_libevent_logging(void);

void suppress_libevent_log_msg(const char *msg);



#ifdef HAVE_EVENT2_EVENT_H

#define tor_event_new     event_new

#define tor_evtimer_new   evtimer_new

#define tor_evsignal_new  evsignal_new

#define tor_event_free    event_free

#else

struct event *tor_event_new(struct event_base * base, evutil_socket_t sock,

           short what, void (*cb)(evutil_socket_t, short, void *), void *arg);

struct event *tor_evtimer_new(struct event_base * base,

            void (*cb)(evutil_socket_t, short, void *), void *arg);

struct event *tor_evsignal_new(struct event_base * base, int sig,

            void (*cb)(evutil_socket_t, short, void *), void *arg);

void tor_event_free(struct event *ev);

#endif



void tor_libevent_initialize(void);

struct event_base *tor_libevent_get_base(void);

const char *tor_libevent_get_method(void);



#endif