bash from local mounted drive with subst command
Mon Feb 21 00:05:32 GMT 2022
Am 21.02.2022 um 00:56 schrieb Takashi Yano:
> On Mon, 21 Feb 2022 08:41:52 +0900
> Takashi Yano wrote:
>> On Sun, 20 Feb 2022 22:38:53 +0100
>> Claude TETE wrote:
>>> A bash in a local mounted drive, use realpath instead of mounted one
>>> for all child processes.
>>> Example, mount a local folder on Z: drive, go in there and run any
>>> external command:
>>> $ subst Z: C:\\Users
>>> $ cd /cygdrive/z/
>>> $ /bin/pwd
>> This is since:
>> commit 19d59ce75d5301ae167b421111d77615eb307aa7
>> Author: Corinna Vinschen <email@example.com>
>> Date: Fri May 7 16:07:03 2021 +0200
>> Cygwin: path_conv: Rework handling native symlinks as inner path components
>> commit 456c3a46386f was only going half-way. It handled symlinks and
>> junction points as inner path components and made realpath return the
>> correct path, but it ignored drive letter substitution, i. e., virtual
>> drives created with, e. g.
>> subst X: C:\foo\bar
>> It was also too simple. Just returning an error code from
>> symlink_info::check puts an unnecessary onus on the symlink evaluation
>> loop in path_conv::check.
>> Rework the code to use GetFinalPathNameByHandle, and only do this after
>> checking the current file for being a symlink failed.
>> If the final path returned by GetFinalPathNameByHandle is not the same
>> as the incoming path, replace the incoming path with the POSIXified
>> final path. This also short-circuits path evaluation, because
>> path_conv::check doesn't have to recurse over the inner path components
>> multiple times if all symlinks are of a native type, while still getting
>> the final path as end result.
>> Virtual drives are now handled like symlinks. This is a necessary change
>> from before to make sure virtual drives are handled identically across
>> different access methods. An example is realpath(1) from coreutils. It
>> doesn't call readlink(2), but iterates over all path components using
>> lstat/readlink calls. Both methods should result in the same real path.
>> Fixes: 456c3a46386f ("path_conv: Try to handle native symlinks more sanely")
>> Signed-off-by: Corinna Vinschen <firstname.lastname@example.org>
>> The behaviour is by design. Does this cause any practical issue?
> The similar happens also in Linux.
> In Debuan GNU/Linux 11.2:
> yano@debian:~$ mkdir -p a/b/c
> yano@debian:~$ ln -s a/b/c c
> yano@debian:~$ cd c
> yano@debian:~/c$ pwd
> yano@debian:~/c$ /bin/pwd
> In cygwin 3.3.4:
> yano@cygwin:~$ mkdir -p a/b/c
> yano@cygwin:~$ ln -s a/b/c c
> yano@cygwin:~$ cd c
> yano@cygwin:~/c$ pwd
> yano@cygwin:~/c$ /bin/pwd
pwd -P will also work like /bin/pwd - but: subst is more comparable to
mount than to ln -s
More information about the Cygwin