How to determine if file is writable and deletable

I need to determine if a file is truly deletable by a php script, Deleting permissions seem to be
the same as writing, they probably have the same criteria.

is_writable() seems to virtually useless in most cases. It doesn't take into account the directory
ownership/permissions; which, best I can tell, is the real determining factor.

I've resorted to having to determine the directory's ownership and then compare the directory's
rights with the owner's and then the other ['world'].

E.g., Assume my script was loaded with ftp, so it's ownership is the site-name, and I want the scrip
to be able to determine if it can delete a file. Thus, the file in question must have its "other"
permissions include write.

Surely, there must be an easier way.

Thanks, Al........

Al wrote:
> I need to determine if a file is truly deletable by a php script,
> Deleting permissions seem to be the same as writing, they probably
> have the same criteria.
>
> is_writable() seems to virtually useless in most cases. It doesn't
> take into account the directory ownership/permissions; which, best I
> can tell, is the real determining factor.
>
> I've resorted to having to determine the directory's ownership and
> then compare the directory's rights with the owner's and then the
> other ['world'].
>
> E.g., Assume my script was loaded with ftp, so it's ownership is the
> site-name, and I want the scrip to be able to determine if it can
> delete a file. Thus, the file in question must have its "other"
> permissions include write.
>
> Surely, there must be an easier way.
>
> Thanks, Al........
>
Hi,

Maybe this is what you need:

http://nl.php.net/manual/en/function.fileperms.php
--

Aschwin Wesselius

/'What you would like to be done to you, do that to the other....'/

You are missing the point of my question. I don't have a problem reading the permissions. They do
not solely determine whether a file can be deleted.

Aschwin Wesselius wrote:
> Al wrote:
>> I need to determine if a file is truly deletable by a php script,
>> Deleting permissions seem to be the same as writing, they probably
>> have the same criteria.
>>
>> is_writable() seems to virtually useless in most cases. It doesn't
>> take into account the directory ownership/permissions; which, best I
>> can tell, is the real determining factor.
>>
>> I've resorted to having to determine the directory's ownership and
>> then compare the directory's rights with the owner's and then the
>> other ['world'].
>>
>> E.g., Assume my script was loaded with ftp, so it's ownership is the
>> site-name, and I want the scrip to be able to determine if it can
>> delete a file. Thus, the file in question must have its "other"
>> permissions include write.
>>
>> Surely, there must be an easier way.
>>
>> Thanks, Al........
>>
> Hi,
>
> Maybe this is what you need:
>
> http://nl.php.net/manual/en/function.fileperms.php

On 07/05/2008, Al <news@ridersite.org> wrote:
> I need to determine if a file is truly deletable by a php script, Deleting
> permissions seem to be
> the same as writing, they probably have the same criteria.

You're not writing to the file, you're unlinking it from the
containing directory, so it's the directory's permissions that matter,
not the file's.

All you really need to do is check that the directory is_writable()

is_writable(dirname($filename));

-robin

If it's not, what else can? I got curious.


Regards,
Thiago Henrique Pojda

-----Mensagem original-----
De: Al [mailto:news@ridersite.org]
Enviada em: quarta-feira, 7 de maio de 2008 12:25
Para: php-general@lists.php.net
Assunto: Re: [php] How to determine if file is writable and deletable

You are missing the point of my question. I don't have a problem reading the
permissions. They do
not solely determine whether a file can be deleted.

Aschwin Wesselius wrote:
> Al wrote:
>> I need to determine if a file is truly deletable by a php script,
>> Deleting permissions seem to be the same as writing, they probably
>> have the same criteria.
>>
>> is_writable() seems to virtually useless in most cases. It doesn't
>> take into account the directory ownership/permissions; which, best I
>> can tell, is the real determining factor.
>>
>> I've resorted to having to determine the directory's ownership and
>> then compare the directory's rights with the owner's and then the
>> other ['world'].
>>
>> E.g., Assume my script was loaded with ftp, so it's ownership is the
>> site-name, and I want the scrip to be able to determine if it can
>> delete a file. Thus, the file in question must have its "other"
>> permissions include write.
>>
>> Surely, there must be an easier way.
>>
>> Thanks, Al........
>>
> Hi,
>
> Maybe this is what you need:
>
> http://nl.php.net/manual/en/function.fileperms.php

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At 11:16 AM -0400 5/7/08, Al wrote:
>I need to determine if a file is truly deletable by a php script,
>Deleting permissions seem to be the same as writing, they probably
>have the same criteria.
>
>is_writable() seems to virtually useless in most cases. It doesn't
>take into account the directory ownership/permissions; which, best I
>can tell, is the real determining factor.
>
>I've resorted to having to determine the directory's ownership and
>then compare the directory's rights with the owner's and then the
>other ['world'].
>
>E.g., Assume my script was loaded with ftp, so it's ownership is the
>site-name, and I want the scrip to be able to determine if it can
>delete a file. Thus, the file in question must have its "other"
>permissions include write.
>
>Surely, there must be an easier way.
>
>Thanks, Al........


Perhaps touch might help.

http://nl.php.net/manual/en/function.touch.php

Cheers,

tedd


--
-------
http://sperling.com http://ancientstones.com http://earthstones.com

> Perhaps touch might help.

Touch my ass.

ROFLMAO

(I've been waiting for years to use that one)

--
Richard Heyes

+----------------------------------------+
| Access SSH with a Windows mapped drive |
| http://www.phpguru.org/sftpdrive |
+----------------------------------------+

At 9:18 PM +0100 5/7/08, Richard Heyes wrote:
>>Perhaps touch might help.
>
>Touch my ass.
>
>ROFLMAO
>
>(I've been waiting for years to use that one)


It won't work?

Cheers,

tedd

--
-------
http://sperling.com http://ancientstones.com http://earthstones.com

> It won't work?

No idea, it was just a rather poor play on words.

--
Richard Heyes

+----------------------------------------+
| Access SSH with a Windows mapped drive |
| http://www.phpguru.org/sftpdrive |
+----------------------------------------+

I ended up using posix_access() which is what is_writeable() should be. is_writeable() is virtually
useless.

Al wrote:
> I need to determine if a file is truly deletable by a php script,
> Deleting permissions seem to be the same as writing, they probably have
> the same criteria.
>
> is_writable() seems to virtually useless in most cases. It doesn't take
> into account the directory ownership/permissions; which, best I can
> tell, is the real determining factor.
>
> I've resorted to having to determine the directory's ownership and then
> compare the directory's rights with the owner's and then the other
> ['world'].
>
> E.g., Assume my script was loaded with ftp, so it's ownership is the
> site-name, and I want the scrip to be able to determine if it can delete
> a file. Thus, the file in question must have its "other" permissions
> include write.
>
> Surely, there must be an easier way.
>
> Thanks, Al........