Fix memory leak in getaddrinfo and make it async exception safe #591
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haskell#587 removed the call to `c_freeaddrinfo` in `getaddrinfo`. This restores it and in addition makes the function async exception safe.
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I meant |
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See the following definition. It uses the same pattern as you wrote. bracketOnError
:: IO a -- ^ computation to run first (\"acquire resource\")
-> (a -> IO b) -- ^ computation to run last (\"release resource\")
-> (a -> IO c) -- ^ computation to run in-between
-> IO c -- returns the value from the in-between computation
bracketOnError before after thing =
mask $ \restore -> do
a <- before
restore (thing a) `onException` after a |
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@kazu-yamamoto seems to me that the result of |
Not really, because I used In any case, I tried to use bracket
(do ret <- c_getaddrinfo c_node c_service c_hints ptr_ptr_addrs
ptr_addrs <- if ret == 0
then peek ptr_ptr_addrs
else return nullPtr
return (ret, ptr_addrs)
)
(\(ret, ptr_addrs) -> do
-- Don't call freeaddrinfo with NULL, it segfaults on some
-- platforms.
when (ret == 0) $ c_freeaddrinfo ptr_addrs
)
(\(ret, ptr_addrs) ->
if ret == 0
then followAddrInfo ptr_addrs
else do
err <- gai_strerror ret
ioError $ ioeSetErrorString
(mkIOError NoSuchThing message Nothing Nothing)
err
)that's why I unrolled it in the first place and I don't think trying to force it is worth it. If you disagree, please fix it the way you like. Also, please make a new release with this fix asap and deprecate 3.2.3.0, 3.2.4.0, 3.2.5.0 and 3.2.6.0 on Hackage because this is a very serious bug. |
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How about something like this? getAddrs = do
ret <- c_getaddrinfo c_node c_service c_hints
if ret == 0
then Right <$> peek ptr_ptr_addrs
else pure $ Left ret
addrErr ret = do
err <- gai_strerror ret
ioError $ ioeSetErrorString
(mkIOError NoSuchThing message Nothing Nothing)
err
bracket
getAddrs
(mapM_ c_freeaddrinfo)
(either addrErr followAddrInfo) |
You are right. After this discussion, the original PR code is simplest, I think. |
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v3.2.7.0 has been released. |
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@kazu-yamamoto |
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My bad. X-( |
#587 removed the call to
c_freeaddrinfoingetaddrinfo.This restores it and in addition makes the function async exception safe.