[GHC] #647: Socket bug on Mac OS X, with patch

[GHC]

#647: Socket bug on Mac OS X, with patch
------------------------------------+---------------------------------------
    Reporter:  gwright at antiope.com  |        Owner:                
        Type:  bug                  |       Status:  new           
    Priority:  normal               |    Milestone:                
   Component:  Compiler             |      Version:  6.4.1         
    Severity:  normal               |     Keywords:  "OS X" Sockets
          Os:  MacOS X              |   Difficulty:  Easy (1 hr)   
Architecture:  powerpc              |  
------------------------------------+---------------------------------------
When using sockets on Mac OS X, some operations may fail with
 EADDRNOTAVAIL.
 This is because a struct sockaddr_in (or struct sockaddr_un) is used
 without being completely zeroed first.  Zeroing the struct first is
 necessary
 on OS X and perhaps older BSDs as well.  The patch below only for darwin.

 The bug was originally detected when trying the Zipper file system (ZFS)
 example.  Without the patch, the program fails; with the patch, it runs
 successfully.  Tested on an OS X 10.4.3, Xcode 2.2, powerbook G4 system.

 -Greg Wright

 patch:

 {{{
 --- libraries/network/Network/Socket.hsc.sav    2006-01-06
 15:12:14.000000000 -0500
 +++ libraries/network/Network/Socket.hsc        2006-01-06
 18:08:48.000000000 -0500
 @@ -357,15 +357,22 @@
     . shows port

  -- we can't write an instance of Storable for SockAddr, because the
 Storable
 --- class can't easily handle alternatives.
 +-- class can't easily handle alternatives. Also note that on Darwin, the
 +-- sockaddr structure must be zeroed before use.

  #if defined(DOMAIN_SOCKET_SUPPORT)
  pokeSockAddr p (SockAddrUnix path) = do
 +#if defined(darwin_TARGET_OS)
 +       zeroMemory p (#const sizeof(struct sockaddr_un))
 +#endif
         (#poke struct sockaddr_un, sun_family) p ((#const AF_UNIX) ::
 CSaFamily)
         let pathC = map castCharToCChar path
         pokeArray0 0 ((#ptr struct sockaddr_un, sun_path) p) pathC
  #endif
  pokeSockAddr p (SockAddrInet (PortNum port) addr) = do
 +#if defined(darwin_TARGET_OS)
 +       zeroMemory p (#const sizeof(struct sockaddr_in))
 +#endif
         (#poke struct sockaddr_in, sin_family) p ((#const AF_INET) ::
 CSaFamily)
         (#poke struct sockaddr_in, sin_port) p port
         (#poke struct sockaddr_in, sin_addr) p addr
 @@ -383,6 +390,11 @@
                 port <- (#peek struct sockaddr_in, sin_port) p
                 return (SockAddrInet (PortNum port) addr)

 +-- helper function used to zero a structure
 +zeroMemory :: Ptr a -> CSize -> IO ()
 +zeroMemory dest nbytes = memset dest 0 (fromIntegral nbytes)
 +foreign import ccall unsafe "string.h" memset :: Ptr a -> CInt -> CSize
 -> IO ()
 +
  -- size of struct sockaddr by family
  #if defined(DOMAIN_SOCKET_SUPPORT)
  sizeOfSockAddr_Family AF_UNIX = #const sizeof(struct sockaddr_un)
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/647>
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