How can I solve this problem ? ?? Who could teach me ...
 

BusyBox v1.19.3 (Debian 1.19.3power3) built-in shell (ash)
Enter 'help' for a list of built-in commands.

~ $ root
sudo: must be setuid root
~ $ ls -l /usr/bin/sudo
-rwxr-xr-x 2 root root 90040 Apr 17 2009 /usr/bin/sudo
~ $ chown root:root /usr/bin/sudo
chown: /usr/bin/sudo: Operation not permitted
~ $ chmod 4755 /usr/bin/sudo
chmod: /usr/bin/sudo: Operation not permitted
~ $ reboot
-sh: reboot: not found

Re: How can I solve this problem ? ?? Who could teach me ...
 

what does "sudo gainroot" do?

Re: How can I solve this problem ? ?? Who could teach me ...
 

BusyBox v1.19.3 (Debian 1.19.3power3) built-in shell (ash)
Enter 'help' for a list of built-in commands.

~ $ sudo gainroot
sudo: must be setuid root

Re: How can I solve this problem ? ?? Who could teach me ...
 

Nothing else happened:


BusyBox v1.19.3 (Debian 1.19.3power3) built-in shell (ash)
Enter 'help' for a list of built-in commands.

~ $ sudo gainroot
sudo: must be setuid root

Re: How can I solve this problem ? ?? Who could teach me ...
 

What does the output give you?Did you try to get rootsh reinstalled, remove it in some Application Manager, and later install it again?

Re: How can I solve this problem ? ?? Who could teach me ...
 

~ $ apt-cache policy rootsh
rootsh:
Installed: 1.8
Candidate: 1.8
Version table:
*** 1.8 0
500 http://repository.maemo.org fremantle/free Packages
100 /var/lib/dpkg/status
1.5 0
500 http://repository.maemo.org fremantle-1.3/free Packages
500 http://repository.maemo.org fremantle/free Packages
500 http://repository.maemo.org fremantle/free Packages
~ $

And neither the stock Application Manager nor Faster Application Manager work ...... I can't even open them .

Re: How can I solve this problem ? ?? Who could teach me ...
 

You may shed some light by remembering, what you did recently before the error appeared.
Did you install something weird? Did you edit sudoers file http://wiki.maemo.org/Root_access#A_note_on_sudo? Did you follow some Howto floating around in the internet ?

Re: How can I solve this problem ? ?? Who could teach me ...
 

If you have ssh installed & setup for root access, then you should be able to get on via that and reset the suid bit on /usr/bin/sudo. You could also try using "su" - I think you'll need to have set up a root password for that though. Otherwise I think you'll need to reflash. If sudo isn't set suid then there's no way for the applications to get root permissions in order to make any other changes.

Re: How can I solve this problem ? ?? Who could teach me ...
 

that 's what I did yesterday:
chmod -R 755 /usr/bin

Re: How can I solve this problem ? ?? Who could teach me ...
 

Yep, that'd do it - you reset the permissions on everything under /usr/bin, stripping off the SUID bit from sudo (and various others). I'd definitely suggest a reflash at this point (and avoiding running that command in future).