bug#22185: Operation not permitted for `touch -d` on 777 file

[Assaf Gordon]

tag 22185 notabug
close 22185
stop

Additional information:

On 12/16/2015 01:19 PM, Assaf Gordon wrote:
> Hello,
>
> On 12/16/2015 09:39 AM, Silvio Ricardo Cordeiro wrote:
> > The following code fails whenever the specified date is different from `now`:

<...>
> > I see no description of that in the documentation, and it just seems wrong. If 
> > other users have full control over the file (and surrounding directory), 
> > shouldn't they be able to change its date?

<...>

> If the above is correct, then this is not a bug in coreutils' touch per-se, but 
> a linux kernel behavior.

I should've looked first at the man page... which states it clearly:

from 'man 2 utimesnsat' :
====
  Permissions requirements
       To  set  both  file timestamps to the current time (i.e., times is NULL, 
or both tv_nsec fields
       specify UTIME_NOW), either:

       1. the caller must have write access to the file;

       2. the caller's effective user ID must match the owner of the file; or

       3. the caller must have appropriate privileges.

       To make any change other than setting both timestamps to the current 
time (i.e., times  is  not
       NULL,  and  both  tv_nsec fields are not UTIME_NOW and both tv_nsec 
fields are not UTIME_OMIT),
       either condition 2 or 3 above must apply.
====

Which means write access (condition 1) is not sufficient to set the time to 
anything except 'now'.
Therefor it is not a coreutils bug - but a linux kernel requirement.

As such, I'm making this as 'closed' - but discussion is welcomed to continue.

regards,
 - assaf