openssh unix dev - Sep 2016 - [PATCH] Allow scp to copy files that start with a Windows drive name.

On Windows, ?scp C:/foo/bar remotehost:? will attempt to connect to
a remote host ?C? and access file ?/foo/bar?. There is currently no
syntax or flag to allow copying files that start with a drive name.

This patch changes the behaviour (only on Cygwin) by considering
that a single letter followed by a colon is a Windows drive name
and thus an absolute path. This is also more consistent with the
manual page that recommends to use absolute pathnames ?to avoid
scp treating file names containing ?:? as host specifiers?.

It is still possible to access files on a machine ?C? by using
square brackets, e.g. ?scp [C]:/foo/bar remotehost:?.

There are countless user reports indicating that this behaviour
is desirable:
 - http://stackoverflow.com/q/8975798/111461
 - http://serverfault.com/q/582048/73723
 - http://superuser.com/q/291840/71253
 - https://www.reddit.com/r/commandline/comments/371q5i
 - http://stackoverflow.com/q/21587036/111461
 - http://askubuntu.com/q/354330/12301
 - http://superuser.com/q/338075/71253
 - https://ubuntuforums.org/archive/index.php/t-1131655.html
 -
http://www.linuxquestions.org/questions/linux-newbie-8/transfer-files-from-linux-to-windows-pscp-4175530524/
---
 misc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/misc.c b/misc.c
index 9421b4d..cd10287 100644
--- a/misc.c
+++ b/misc.c
@@ -435,6 +435,10 @@ colon(char *cp)
 
 	if (*cp == ':')		/* Leading colon is part of file name. */
 		return NULL;
+#ifdef HAVE_CYGWIN
+	if (isalpha(*cp) && *(cp+1) == ':')	/* Do not split at drive
name. */
+		return NULL;
+#endif
 	if (*cp == '[')
 		flag = 1;
 
-- 
2.1.4

Quoth Sam:
On Windows, ?scp C:/foo/bar remotehost:? will attempt to connect to a remote
host ?C?
and access file ?/foo/bar?. There is currently no syntax or flag to allow
copying files that start with a drive name.

This patch changes the behaviour (only on Cygwin) by considering that a single
letter followed by a colon is a Windows drive name and thus an absolute path.
This is also more consistent with the manual page that recommends to use
absolute pathnames ?to avoid scp treating file names containing ?:? as host
specifiers?.
-----------------------

Is this really necessary?   Especially since it's a Cygwin specific patch,
what is wrong with simply using /cygdrive/C/foo/bar?

It should work if you quote the ':' character with a '\' ... no
need
for the patch.

Ced

On 20 September 2016 at 17:35, Scott Neugroschl <scott_n at xypro.com>
wrote:
> Quoth Sam:
> On Windows, ?scp C:/foo/bar remotehost:? will attempt to connect to a
remote host ?C?
> and access file ?/foo/bar?. There is currently no syntax or flag to allow
copying files that start with a drive name.
>
> This patch changes the behaviour (only on Cygwin) by considering that a
single letter followed by a colon is a Windows drive name and thus an absolute
path. This is also more consistent with the manual page that recommends to use
absolute pathnames ?to avoid scp treating file names containing ?:? as host
specifiers?.
> -----------------------
>
> Is this really necessary?   Especially since it's a Cygwin specific
patch, what is wrong with simply using /cygdrive/C/foo/bar?
>
>
> _______________________________________________
> openssh-unix-dev mailing list
> openssh-unix-dev at mindrot.org
> https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev


-- 
Cedric Blancher <cedric.blancher at gmail.com>
[https://plus.google.com/u/0/+CedricBlancher/]
Institute Pasteur

On Tue, Sep 20, 2016, Scott Neugroschl wrote:
> This patch changes the behaviour (only on Cygwin) by considering that a
> single letter followed by a colon is a Windows drive name and thus an
> absolute path. This is also more consistent with the manual page that
> recommends to use absolute pathnames ?to avoid scp treating file names
> containing ?:? as host specifiers?.
> 
> -----------------------
> 
> Is this really necessary?   Especially since it's a Cygwin specific
patch, what is wrong with simply using /cygdrive/C/foo/bar?
   The patch uses HAVE_CYGWIN but is not Cygwin-specific, it also applies to
MSYS2 which is a modern Cygwin fork and does not have /cygdrive/C/ (it uses /c/
directly instead).

   Also an interactive user may immediately correct the error by changing
the path to a Unix-like one instead, but sometimes the arguments are not
user-controlled, or scp is used together with non-Cygwin applications, or is
embedded into a larger script that expects scp to behave as documented for
absolute paths. From a least surprise perspective, I believe the correct place
to fix this is indeed in scp.

   Finally, drives in /cygdrive/ (or in MSYS2 /c/) are not immediately
accessible; a newly mounted network device or thumb drive will fail to appear
unless the terminal is closed and a new one is opened. If the shell is a child
of sshd.exe it would even require a restart of the SSH server.

Regards,
-- 
Sam.

On Tue, Sep 20, 2016, Sam Hocevar wrote:
> On Windows, ?scp C:/foo/bar remotehost:? will attempt to connect to
> a remote host ?C? and access file ?/foo/bar?. There is currently no
> syntax or flag to allow copying files that start with a drive name.
   Any comments on this patch maybe? Right now it is impossible to do
?scp 'C:\foo\bar' remotehost:? on Windows.

Regards,
-- 
Sam.