[tor-bugs] #19904 [Core Tor/Tor]: evutil_secure_rng_add_bytes() not present in openbsd libevent 2

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#19904: evutil_secure_rng_add_bytes() not present in openbsd libevent 2
----------------------------------------+----------------------------------
 Reporter:  nickm                       |          Owner:  nickm
     Type:  defect                      |         Status:
                                        |  needs_information
 Priority:  Medium                      |      Milestone:  Tor:
                                        |  0.2.9.x-final
Component:  Core Tor/Tor                |        Version:
 Severity:  Normal                      |     Resolution:
 Keywords:  openbsd, TorCoreTeam201608  |  Actual Points:  0
Parent ID:                              |         Points:  0
 Reviewer:                              |        Sponsor:
----------------------------------------+----------------------------------

Comment (by rubiate):

 Nope, it can't find evutil_secure_rng_add_bytes or
 evutil_secure_rng_set_urandom_device_file because it's still looking with
 -levent

     configure:8355: checking for evutil_secure_rng_set_urandom_device_file
     configure:8355: gcc -std=gnu99 -o conftest -g -O2 -I/usr/local/include
 -I${top_srcdir}/src/common -L/usr/local/lib  conftest.c -levent
 -lpthread  >&5
     /tmp//cc7rk6IF.o: In function `main':
     /tor/conftest.c:99: undefined reference to
 `evutil_secure_rng_set_urandom_device_file'
     [...]
     configure:8355: checking for evutil_secure_rng_add_bytes
     configure:8355: gcc -std=gnu99 -o conftest -g -O2 -I/usr/local/include
 -I${top_srcdir}/src/common -L/usr/local/lib  conftest.c -levent
 -lpthread  >&5
     /tmp//cc2XrDZc.o: In function `main':
     /tor/conftest.c:99: undefined reference to
 `evutil_secure_rng_add_bytes'

 With things moved around, it can find
 evutil_secure_rng_set_urandom_device_file

     configure:8507: checking for evutil_secure_rng_set_urandom_device_file
     configure:8507: gcc -std=gnu99 -o conftest -g -O2 -I/usr/local/include
 -I${top_srcdir}/src/common -L/usr/local/lib  conftest.c -levent_extra
 -levent_core   -lpthread  >&5
     configure:8507: $? = 0
     configure:8507: result: yes
     [...]
     configure:8507: checking for evutil_secure_rng_add_bytes
     configure:8507: gcc -std=gnu99 -o conftest -g -O2 -I/usr/local/include
 -I${top_srcdir}/src/common -L/usr/local/lib  conftest.c -levent_extra
 -levent_core   -lpthread  >&5
     /tmp//ccmjPCe2.o: In function `main':
     /tor/conftest.c:103: undefined reference to
 `evutil_secure_rng_add_bytes'


 Updated to apply against current master:

 {{{
 diff --git a/configure.ac b/configure.ac
 index f6edb3a..23371d3 100644
 --- a/configure.ac
 +++ b/configure.ac
 @@ -490,21 +490,17 @@ void *event_init(void);],
  event_init();
  ], [--with-libevent-dir], [/opt/libevent])

 -dnl Now check for particular libevent functions.
 +dnl Determine the incantation needed to link libevent.
  save_LIBS="$LIBS"
  save_LDFLAGS="$LDFLAGS"
  save_CPPFLAGS="$CPPFLAGS"
 -LIBS="-levent $STATIC_LIBEVENT_FLAGS $TOR_LIB_WS32 $LIBS"
 +
 +LIBS="$STATIC_LIBEVENT_FLAGS $TOR_LIB_WS32 $save_LIBS"
  LDFLAGS="$TOR_LDFLAGS_libevent $LDFLAGS"
  CPPFLAGS="$TOR_CPPFLAGS_libevent $CPPFLAGS"
 -AC_CHECK_FUNCS([evutil_secure_rng_set_urandom_device_file \
 -                evutil_secure_rng_add_bytes \
 -])

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

 -LIBS="$STATIC_LIBEVENT_FLAGS $TOR_LIB_WS32 $save_LIBS"
 -
  if test "$enable_static_libevent" = "yes"; then
     if test "$tor_cv_library_libevent_dir" = "(system)"; then
       AC_MSG_ERROR("You must specify an explicit --with-libevent-dir=x
 option when using --enable-static-libevent")
 @@ -527,6 +523,11 @@ else
       fi
  fi

 +dnl Now check for particular libevent functions.
 +AC_CHECK_FUNCS([evutil_secure_rng_set_urandom_device_file \
 +                evutil_secure_rng_add_bytes \
 +])
 +
  LIBS="$save_LIBS"
  LDFLAGS="$save_LDFLAGS"
  CPPFLAGS="$save_CPPFLAGS"
 }}}

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/19904#comment:6>
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