hClose leaves file descriptor open if it fails
In libraries/base/GHC/Handle.hs, function hClose_help, we attempt to flush the write buffer before closing a handle's underlying FD.
If flushing the write buffer fails, for example if this is a network socket that has been closed by the remote host, hClose throws an exception inside flushWriteBufferOnly and the socket is not closed. As a result, the program leaks sockets.
The solution is to always close the FD (that is, call hClose_handle_) regardless of errors, but I am not confident of writing correct exception-handling code without the usual abstractions available.
Also, inside hClose_handle_, an error is thrown if c_close ever returns -1. It may be practically impossible for this to be caused by EINTR, but is it theoretically impossible?
Trac metadata
| Trac field | Value |
|---|---|
| Version | 6.10.1 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | libraries/base |
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