Creating an ftp incoming directory that allows write but not delete

[Fahrvergnuugen]

I want to create a directory that allows ftp users to write files but not delete them.

Here's what I want:
Anonymous users can upload files, download files, list the directory, but NOT delete any files [even ones they've uploaded].

I'm guessing that this can't be done with file system permissions, because the write flag gives create / delete access at the same time.

So does that mean the only way to do this is through the ftp server software? I'm using Pureftpd now but I haven't been able to figure out how to setup the incoming directory the way I want.

 

[Fahrvergnuugen]

pureftpd allows you to execute an external shell command after an action...I think I'm going to make it chmod the file that the user just uploaded so that it can't be deleted.

 

[Fahrvergnuugen]

well, the problem is all the ftp users use the same system account. they are all virtual users that use the ftp_user / ftp_group that i setup on my machine.

I want people to be able to download stuff in the uploads directory, I just don't want anybody to be able to delete anything anywhere.

I think the solution is to make use of the "external shell command upon successfull upload"...I'm sure this is the reason such a feature exists.