Use WSA_FLAG_NO_HANDLE_INHERIT on Windows for cloexec sockets
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MisterDA
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WSA_FLAG_NO_HANDLE_INHERIT on Windows for cloexec sockets
smorimoto
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Dec 20, 2021
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Please don't merge, the PR is also under review in OCaml. I'll "backport" the changes after review here too. |
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The call to
socket(domain, type, protocol);
is equivalent to
WSASocket(domain, type, protocol, NULL, 0, WSA_FLAG_OVERLAPPED);
the latter offering more (needed) control over the creation of
sockets.
On Windows, in order to mark sockets non-inheritable (close-on-exec), it is sometimes not sufficient to use SetHandleInformation. There's some explanation why in [1] and [KB2398202]. Introduced in the hotfix [KB2398202] and supported on Windows 7 with SP1, Windows Server 2008 R2 with SP1, and later, the flag WSA_FLAG_NO_HANDLE_INHERIT can be used with WSASocket to create a non-inheritable socket. We can still call SetHandleInformation to clear the inheritable flag on the socket in case the flag isn't supported (running on an early Windows Vista or 7). Related OCaml PR: - ocaml/ocaml#10809. [1]: https://stackoverflow.com/questions/12058911/can-tcp-socket-handles-be-set-not-inheritable [KB2398202]: https://support.microsoft.com/en-us/topic/an-application-may-stop-responding-when-the-application-closes-a-socket-connection-or-shuts-down-41321a1f-d80c-6975-98df-ae499d63133c
MisterDA
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The corresponding PR was just merged in OCaml. |
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Looks good to me (cc @raphael-proust) |
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Looks ok to me although I don't know nearly enough about the windows system code to make sense of that part and I don't have a machine to test it on. Still, it looks ok and the Unix part definitely looks fine. |
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The call to
is equivalent to
the latter offering more (needed) control over the creation of
sockets.
On Windows, in order to mark sockets non-inheritable (close-on-exec),
it is sometimes not sufficient to use
SetHandleInformation. There'ssome explanation why in 1 and KB2398202.
Introduced in the hotfix KB2398202 and supported on Windows 7 with
SP1, Windows Server 2008 R2 with SP1, and later, the flag
WSA_FLAG_NO_HANDLE_INHERITcan be used withWSASocketto create anon-inheritable socket.
We can still call
SetHandleInformationto clear the inheritable flagon the socket in case the flag isn't supported (running on an early
Windows Vista or 7).
Related OCaml PR:
socketwithWSASocketand setWSA_FLAG_NO_HANDLE_INHERITocaml/ocaml#10809.