Re: Getting TRAMP 2.0.25 working in NT Emacs 21.2.1 with Cygwin 1.3.12-1

[Kai Großjohann]

Francis Litterio <address@hidden> writes:

> Here's what I had to do to make it work:
>
> 1. In my .emacs startup file, I do:
>
>       (require 'tramp)
>       (setq tramp-default-method "scpx")
>
>    This is required when using TRAMP under NT Emacs as described in the
>    manual.
>
>    to load up TRAMP.  I have load-path set appropriately.

Right.  Nothing special here.  Or am I missing something?

> 2. Next, my .emacs file executes this horror:
>
>       (let ((shell-file-name "c:/apps/cygwin/bin/bash.exe"))
>         (shell-command "echo /tmp/ssh-*/agent.* 2>/dev/null" " *temp*"))
>       (save-excursion
>         (set-buffer " *temp*")
>         (end-of-line)
>         (if (> (buffer-size) 5)
>             (setenv "SSH_AUTH_SOCK" (buffer-substring (point-min) (point)))
>           (ding)
>           (message "my-general.el: WARNING: ssh-agent is not running!")
>           (sit-for 3)))
>
>    The above mess is to cope with what I think is a fairly common
>    situation -- namely, where the user launches NT Emacs using a
>    shortcut on the desktop but starts ssh-agent from a bash shell also
>    launched from the desktop.  Since Emacs is not a descendant of
>    ssh-agent, it does not inherit the SSH_AUTH_SOCK environment
>    variable (and neither does scp).
>
>    My solution (above) is a total hack.  It malfunctions if the echo
>    command outputs more than one pathname, which happens if you have old
>    ssh-agent socket directories lying around.  If TRAMP had were to call
>    a hook at just the right moment, I could write some Elisp to find the
>    most recent ssh-agent socket file and setenv the SSH_AUTH_SOCK
>    environment variable within Emacs.
>
>    Maybe the general solution is to create a tramp-methods key named
>    tramp-pre-rcp-hook, which is run just before tramp-rcp-program
>    executes?

Whee.  Isn't it enough to do it when Emacs starts, or perhaps when
Tramp is loaded?

> 3. Next, I had to make the following change to lisp/tramp.el.
>
>       ***************
>       *** 3113,3118 ****
>       --- 3113,3119 ----
>           "Like `insert-file-contents' for tramp files."
>           (barf-if-buffer-read-only)
>           (setq filename (expand-file-name filename))
>       +   (setq buffer-file-name filename)
>           (with-parsed-tramp-file-name filename nil
>             (when (tramp-ange-ftp-file-name-p multi-method method user host)
>               (tramp-invoke-ange-ftp 'insert-file-contents
>
>    This may not be the right thing to do, but it prevents a
>    wrong-type-argument error from vc-file-not-found-hook and from
>    find-file-noselect-1 when they each evaluate (file-truename
>    buffer-file-name) with buffer-file-name set to nil.

It is indeed not the right thing to do, since (if I understand
correctly) this means that buffer-file-name changes if you do C-x i
/some/other/file RET (if the other file is remote so that the above
code is executed).

Can you find out why vc-file-not-found-hook and find-file-noselect-1
complain when it is done via Tramp but not for local files?  Maybe
the problem can be solved another way.

> 4. Next, I had to make the following change to lisp/tramp.el.
>
>       *** 3024,3030 ****
>               (unless (file-exists-p filename)
>               (error "Cannot make local copy of non-existing file `%s'"
>                      filename))
>       !       (setq tmpfil (tramp-make-temp-file))
>               (cond (rcp-program
>                    ;; Use rcp-like program for file transfer.
>                    (tramp-message-for-buffer
>       --- 3024,3030 ----
>               (unless (file-exists-p filename)
>               (error "Cannot make local copy of non-existing file `%s'"
>                      filename))
>       !       (setq tmpfil (substring (tramp-make-temp-file) 2))
>               (cond (rcp-program
>                    ;; Use rcp-like program for file transfer.
>                    (tramp-message-for-buffer
>
>    This is to cope with the fact that, by default, NT Emacs has
>    temporary-file-directory set to C:/DOCUME~1/username/LOCALS~1/Temp/,
>    which is unacceptable to Cygwin's scp as the second argument, because
>    scp interprets the "c:" as a hostname!  The substring call chops off
>    the "C:", leaving tmpfil set to a value that is acceptable to both
>    Cygwin's scp and NT Emacs (and, more importantly, means the same
>    thing to both of them).

Would it help to introduce a kludge variable tramp-temp-dir which
defaults to nil?  You could set it to the right value, without "C:".

kai
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