Re: PATCH: Run builtins, functions, etc. under zpty

["Bart Schaefer" <schaefer@candle.brasslantern.com>]

On Nov 8,  3:38pm, Andrej Borsenkow wrote:
} Subject: RE: PATCH: Run builtins, functions, etc. under zpty
} 
} Attempt to run any (external) command with zpty under Cygwin now results in:
} 
} zsh: can't set tty pgrp: not owner

Hrm.  Does the clone module fail under cygwin as well?  (I'm not sure
how you would test it, frankly, but if you can think of a way ...)

} (from child process) and hanging? zsh.

Do you mean that the "can't set tty pgrp" message appears on the pty,
that is, that you read it back with "zpty -r"?  (If it shows up on the
parent zsh's tty, it can't be from the child, because stdin/out/err
are dup2'd before any such message could be generated.)

} This happens with the version of cygwin that did work before, so it is very
} much related to the changes in zsh. The messages above comes from attachtty,
} but I am not sure when it is executed

The only way attachtty() gets called (with 13123 applied) is from init_io(),
and the message above can only happen if tcsetpgrp() or ioctl(TIOCSPGRP)
both failed.  This means that the old code at abount line 310 of (the pre-
13123) zpty.c must also have been failing, but was never testing its return
value and so was silent.

The same set of terminal-initialization system calls that was happening
before 13123 should still be happening, just in slightly different order
because of using init_io() -- e.g. some calls that were previously made
directly on the `slave' descriptor are now made on the dup'd copies of
that descriptor.  But that *shouldn't* make any difference -- unless
ttyname(0) and ttyname(1) are both failing.

} and what happens after this, i.e. why zsh apparently "hangs".

Just to be sure I understand -- which zsh appears to be hung?  The parent
from which you issued the zpty command, or the child that's supposed to
be on the new pty?  I think you mean the child.

} That is what I have in process list:
} 
} $ ps -l
}       PID    PPID    PGID     WINPID TTY  UID    STIME COMMAND
}      1696       1    1696       1696   0 1006 15:22:33 /usr/bin/bash
}       580       1     580        580   1 1006 15:22:34 /usr/bin/zsh
}      2328     580    2328       2328  -1 1006 15:22:52 /usr/bin/zsh
}      2188    1696    2188       1904   0 1006 15:28:35 /usr/bin/ps
} 
} for "zpty sh /bin/sh". Zsh does not appear to execute command at all, but it
} does not exit either.

The only thing that happens after attachtty() is that the command is
executed with execode().  If attachtty() has failed, MONITOR will have
been turned off (as well as INTERACTIVE) before execode() runs.

To see whether the hang is execode()-related, try replacing that with a
call to
	execve(findcmd(args[0], 1), args, environ);

That should be at line 361 of zpty.c, as it stands in cvs.

-- 
Bart Schaefer                                 Brass Lantern Enterprises
http://www.well.com/user/barts              http://www.brasslantern.com

Zsh: http://www.zsh.org | PHPerl Project: http://phperl.sourceforge.net