Solaris

I have a peculiar problem.
I have a particular directory with the following characteristics:

-bash-3.00# ls -lah
total 18
drwxr-x--- 7 gandalf shire 512 jul 3 07:20 .
drwxr-x--- 11 gandalf shire 512 mai 10 2010 ..
drwxr-xr-x 6 gandalf shire 3,0K jul 24 19:25 brasdeff
drwxr-xr-x 2 gandalf shire 512 mar 20 17:03 brasesmm
drwxr-xr-x 3 gandalf shire 512 mar 20 17:00 brasfrpp
drwxr-xr-x 2 gandalf shire 512 jul 6 10:37 brasptpl


I need to create a user for FTP access, which we call here 'hobbit';
How to create this user, hobbit, has write access to these folders, without changing the permissions writing these folders and without changing the 'owner'?

Not directly possible based on the information shown. You only have write permissions for owner, not group or other.

(Note: I would not even consider having a duplicate UID).

Other techniques available include giving the ftp user a normal isolated home directory and using a periodic root cron to collect data and place it into the final directories with the correct permissions. This technique needs an interlock mechanism on the relay directory to ensure that ftp transfers finish before file copying takes place.

So, you want to change the permissions without changing them. I'm afraid that's not going to work.

If you make the folder group-writable and put your hobbit in the 'shire' group they will have access.

I Solved my problem!
I used the commands:

# id gandalf
uid=100(gandalf) gid=104
# usermod -u 100 -o hobbit


With the same ID of Gandalf, the hobbit can write to the folder 'brasdeff', for example.

Not recommended to have two users with the same UID. As well as being just plain confusing, it can cause backup and restore software to malfunction. You might as well do the ftp process as user gandalf.
Don' forget that any files previously owned by user hobbit are now orphans.

Thanks for the warning! I'll try to be careful, but as that user hobbit is only for specific access to this folder, and will be for processes like 'put' and 'get', I think that's enough.
I can not allow the user to login with Gandalf, since this user has a password that can not provide, since it is used by a critical system.

Thank you!

I'm not sure what will happen now if they attempt to change their password, though.