GNU bug report logs - #18937
chmod ???? bug?

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Message #18 received at submit <at> debbugs.gnu.org (full text, mbox):

From: f0rhum <f0rhum <at> free.fr>
To: bug-coreutils <at> gnu.org
Subject: Re: bug#18937: chmod ???? bug?
Date: Thu, 06 Nov 2014 10:43:42 +0100

Le 04/11/2014 18:47, Bob Proulx a écrit :
> Plato wrote:
>> After using chmod
>> 	chmod -R 644 /media/plato/mountedpartition/	(I see I forgot the * at the end)
> That is a problematic command regardless of the '*' at the end or
> not.  If any of the arguments is a directory then it will set the
> directory permission to 644 as specified.  But directories need the
> 'x' bit (execute permission) set as well.
>
> The above command will remove the execute bit from
> /media/plato/mountedpartition and then fail to search below it due to
> permission problems.  It will then leave the directory in an unhappy
> state.
>
>> 	ls -l
>> listing has all entry's like these:
>> 	First a list like this of every file and folder
>> 		ls: cannot access /media/plato/mountedpartition/justafiile.txt: Permission denied
> That is correct when the execute permission is removed from a directory.
>
>> When I do
>> 	sudo ls Files
>> I get a listing of the contents of files as expected.
> This is because file mode bits only apply to non-root access.  Root is
> the superuser and always has permission regardless of the file mode
> bits.  Root always has access regardless of permissions.
>
>> Is this a bug?
> No.  It is doing exactly what you told it to do.
>
> Try this:
>
>   ls -ld /media/plato/mountedpartition
>
> The -d option will tell ls to show the argument itself instead of
> showing the contents of the directory.  With that you will see
> something like this mode bits: drw-r--r-- but directories need to have
> the x bit there too like drwxrwxr-x typically.
>
>> It was not my intention to get this. I do not know how to get it back to what it was.
>> I tried it on a single file with
>> 	chmod 644 justafile.txt
>> but that did not solve it. Any ideas?
> After removing the execute bit from the directory you simply must add
> the execute bit back to the directory.  It will probably be enough to
> do this using symbolic modes.
>
>   chmod a+x /media/plato/mountedpartition
>
> In the old numeric form, combined with your previous 644, this would
> be similar to:
>
>   chmod 755 /media/plato/mountedpartition
>
> Do not use the -R option with numeric arguments such as 644 because
> the numeric mode will be recursively applied across directories.  That
> is almost never what you want.  If using the -R option it is safer to
> use the symbolic modes such as go-w.
>
> Since this is all expected behavior I am going to go ahead and close
> this bug.  However please continue the discussion here in the bug
> log.  Any replies are still seen and discussed by the group.
>
> Bob
>
>
>
chmod -R u=rwX,g=rwX[s],o=[---|rX|rwX] /media/plato/mountedpartition/
(no need the *, implied by -R)

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