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Re: OpenSSH and WinCVS in Windows 9x
Thursday, 08 August, 2002 Laurent Pinchart email@example.com wrote:
LP> WinCVS creates the ssh process by calling CreateProcess, which has stdin and
LP> stdout redirected to pipes. The pipes are then converted to C file
LP> descriptors, which in turn are converted to FILE pointers. Closing those
LP> FILEs doesn't make ssh terminate.
LP> I tried to modify the WinCVS code, and closed all the pipe handles right after
LP> creating the child process (ssh). This doesn't make the child process
LP> I suppose that it is then a bug in OpenSSH/Cygwin. I'll try to investigate in
LP> the OpenSSH sources. My guess is that OpenSSH calls select() on the standard
LP> input, and fails to detect that the pipe has been closed. Once again, this
LP> only occurs in Win98, not in Win2k.
Cygwin uses the following code to periodically probe pipe status:
peek_pipe (select_record *s, bool from_select)
else if (!PeekNamedPipe (h, NULL, 0, NULL, (DWORD *) &n, NULL))
select_printf ("%s, PeekNamedPipe failed, %E", fh->get_name ());
n = -1;
Peeking into pipe for zero bytes is quite unusual, so win98 may return
something wrong here. You can probably attach with a debugger or strace
to running ssh instance and look what's going on. Maybe we'd have to
probe for at least 1 byte here. Or maybe use some totally different
approach to detect if peer's end of pipe is closed.
I vaguely remember some problems with PeekNamedPipe from times when i
patched tty stuff, but they were somewhat different.
LP> I'm not very familiar with pipes on windows, so I'd appreciate help on this
Egor. mailto:firstname.lastname@example.org ICQ 5165414 FidoNet 2:5020/496.19
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