In what way is /cygdrive special WRT to permissions?

[Andy Hall]

One final note on this:

At Jeremy's suggestion, I tried changing the way /cygdrive is mounted.  As
Administrator I changed /etc/fstab to read

//vega/repository /repos smbfs binary,noacl 0 0
none /cygdrive cygdrive binary,noacl,user 0 0

Mount now shows

Administrator@taurus ~
$ mount
//vega/repository on /repos type smbfs (binary,noacl)
C:/cygwin/bin on /usr/bin type ntfs (binary,auto)
C:/cygwin/lib on /usr/lib type ntfs (binary,auto)
C:/cygwin on / type ntfs (binary,auto)
C: on /cygdrive/c type ntfs (binary,noacl,posix=0,user,noumount,auto)
D: on /cygdrive/d type iso9660 (binary,noacl,posix=0,user,noumount,auto)
F: on /cygdrive/f type smbfs (binary,noacl,posix=0,user,noumount,auto)
H: on /cygdrive/h type smbfs (binary,noacl,posix=0,user,noumount,auto)

Note that all drives now seem to inherit noacl from the mount of /cygdrive
which for C: may not be what you want either.  

An ls -l of /cygrive/f now shows

Administrator@taurus ~
$ ls -l /cygdrive/f
total 2048
drwxr-xr-x 36 Administrator None 0 2010-10-07 12:35 builds
drwxr-xr-x 17 Administrator None 0 2010-10-04 18:23 releases

and testing the ability to write you have

Administrator@taurus ~
$ test -w /cygdrive/f/builds && echo you can write
you can write

This was always the case when you have Administrator privileges.

But, when logged in as user build which does not have Administrator
privileges, you now have:

$ ls -l /cygdrive/f
total 2048
drwxr-xr-x 36 build None 0 2010-10-07 12:35 builds
drwxr-xr-x 17 build None 0 2010-10-04 18:23 releases

and

$ test -w /cygdrive/f/builds && echo You can write
You can write

Which is the way cygwin 1.5 behaved!  

Perhaps the default mounting of file systems that are not NTFS should be
with noacl, but that is a question best answered by more knowledgeable
people.  It would at least make the behavior of test consistent which what
you can actually do with the filesystem.


> 
> Corinna -
> 
> Thanks for the reply and clarification.  I have made the obvious change in
> my mounts to get around this problem.   However, there has been a change
> in behavior between 1.5 and 1.7.   I have 1.7.7 installed on Windows
> Server 2003 SP2.
> 
> The mount table shows
> 
> $ mount
> //vega/repository on /repos type smbfs (binary,noacl)
> C:/cygwin/bin on /usr/bin type ntfs (binary,auto)
> C:/cygwin/lib on /usr/lib type ntfs (binary,auto)
> C:/cygwin on / type ntfs (binary,auto)
> C: on /cygdrive/c type ntfs (binary,posix=0,user,noumount,auto)
> D: on /cygdrive/d type iso9660 (binary,posix=0,user,noumount,auto)
> F: on /cygdrive/f type smbfs (binary,posix=0,user,noumount,auto)
> H: on /cygdrive/h type smbfs (binary,posix=0,user,noumount,auto)
> 
> F: also happens to be mapped to //vega/repository via the normal Windows
> mechanisms.
> 
> When signed on to the Administrator account you have:
> 
> Administrator@taurus ~
> $ ls -l /repos
> total 2048
> drwxr-xr-x 36 Administrator None 0 2010-10-04 19:30 builds
> drwxr-xr-x 17 Administrator None 0 2010-10-04 18:23 releases
> 
> Administrator@taurus ~
> $ test -w /repos/builds && echo writeable
> writeable
> 
> Administrator@taurus ~
> $ ls -l /cygdrive/f
> total 2048
> drwxrwxr-x 36 ???????? ???????? 0 2010-10-04 19:30 builds
> drwxrwxr-x 17 ???????? ???????? 0 2010-10-04 18:23 releases
> 
> Administrator@taurus ~
> $ test -w /repos/builds && echo writeable
> writeable
> 
> When logged on as the non-admistrative user build you have:
> 
> build@taurus ~
> $ ls -l /repos
> total 2048
> drwxr-xr-x 36 build None 0 2010-10-04 19:30 builds
> drwxr-xr-x 17 build None 0 2010-10-04 18:23 releases
> 
> build@taurus ~
> $ test -w /repos/builds && echo writeable
> writeable
> 
> build@taurus ~
> $ ls -l /cygdrive/f
> total 2048
> drwxrwxr-x 36 ???????? ???????? 0 2010-10-04 19:30 builds
> drwxrwxr-x 17 ???????? ???????? 0 2010-10-04 18:23 releases
> 
> build@taurus ~
> $ test -w /cygdrive/f/builds && echo writeable
> 
> build@taurus ~
> $ echo test >/cygdrive/f/builds/zap
> 
> build@taurus ~
> $ ls -l /cygdrive/f/builds/zap
> -rwxrwxr-x 1 ???????? ???????? 5 2010-10-06 16:11 /cygdrive/f/builds/zap
> 
> Notice that the test -w /cygdrive/f/builds reports that /cygdrive/f/builds
> is not writeable, yet you can create and write files in
> /cygdrive/f/builds!
> THIS IS INCONSTENT BEHAVIOR.  Cygwin 1.5 did not have this behavior.
> 
> Regarding the mount of drive letters via /etc/fstab. I am not sure what
> the documentation should say about this.  Overriding the default mount of
> a single drive letter in fstab actually seems to work, although it simply
> reproduces the same behavior as the default.
> 
> Even if I understood the actual behavior, I regret that am not familiar
> with the ways of Cygwin source maintenance to make the documentation
> changes.  I have to leave this to somebody else more qualified.
> 
> Cheers, Andy
> 
> 
> > On Oct  6  1:48 Corinna Vischen wrote:
> >
> >
> > On Oct  5 15:40, Andy Hall wrote:
> > > If instead, I map F: to /cygdrive/c with the following entry in
> > /etc/fstab
> > >
> > > F: /cygdrive/f smbfs binary,noacl 0 0
> > >
> > > mount shows
> > >
> > > $ mount
> > > C:/cygwin/bin on /usr/bin type ntfs (binary,auto)
> > > C:/cygwin/lib on /usr/lib type ntfs (binary,auto)
> > > C:/cygwin on / type ntfs (binary,auto)
> > > F: on /cygdrive/f type smbfs (binary,noacl)
> > > C: on /cygdrive/c type ntfs (binary,posix=0,user,noumount,auto)
> > >
> > > And ls -l of /cygdrive/f shows
> > >
> > > $ ls -l /cygdrive/f
> > > total 2048
> > > drwxrwxr-x 36 ???????? ???????? 0 2010-10-04 16:30 builds
> > > drwxrwxr-x 17 ???????? ???????? 0 2010-10-04 15:23 releases
> > > [...]
> > > Why am I getting -1 for the uid and gid when I mount to /cygdrive/f
> but
> > not
> > > to /repos1?
> >
> > That's a restriction of the cygdrive prefix handling.  You can't
> > override the cygdrive mount options for a single drive.  It's an
> > all or nothing thingy.  I guess it would help to refuse such paths
> > in /etc/fstab or mount(1), or at least improve the documentation,
> > but, well, http://cygwin.com/acronyms/#SHTDI.
> >
> >
> > Corinna
> >
> > --
> > Corinna Vinschen                  Please, send mails regarding Cygwin to
> > Cygwin Project Co-Leader          cygwin AT cygwin DOT com
> > Red Hat
> >
> > --
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