[tor-bugs] #5762 [Tor Client]: SOCK_CLOEXEC should get ENOSYS, not EINVAL, on accept()

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#5762: SOCK_CLOEXEC should get ENOSYS, not EINVAL, on accept()
------------------------+---------------------------------------------------
 Reporter:  arma        |          Owner:                    
     Type:  defect      |         Status:  new               
 Priority:  normal      |      Milestone:  Tor: 0.2.3.x-final
Component:  Tor Client  |        Version:                    
 Keywords:              |         Parent:                    
   Points:              |   Actualpoints:                    
------------------------+---------------------------------------------------
 In #5112 we added a bunch of checks to ignore open(), accept4(), etc
 failures if errno is EINVAL.

 But it would appear the accept4() sets errno to ENOSYS, not EINVAL, if the
 system lacks O_CLOEXEC support.

 A quick google led me to
 https://projects.honeynet.org/svn/sebek/virtualization/qebek/trunk/osdep.c
 which handles EINVAL in most cases but ENOSYS in the accept4() case.

 Here's the simple patch, but it probably wants a changes stanza and a much
 better explanation in the comment if we like it:
 {{{
 diff --git a/src/common/compat.c b/src/common/compat.c
 index fbb37ce..490deea 100644
 --- a/src/common/compat.c
 +++ b/src/common/compat.c
 @@ -1016,7 +1016,7 @@ tor_accept_socket(tor_socket_t sockfd, struct
 sockaddr *
    /* If we got an error, see if it is EINVAL. EINVAL might indicate that,
     * event though we were built on a system with accept4 support, we
     * are running on one without. */
 -  if (errno != EINVAL)
 +  if (errno != ENOSYS)
      return s;
  #endif
 }}}

 See also http://osdir.com/ml/ruby-talk/2012-03/msg00082.html

 Reported by murb.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/5762>
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