Help with permissions under Rainbow sought

Sascha Silbe sascha-ml-ui-sugar-olpc-devel at
Sun Apr 18 08:10:27 EDT 2010

On Sat, Apr 17, 2010 at 09:26:23PM -0400, George Hunt wrote:

> I am using an ipython console application which writes a history file 
> to the home directory (I changed the HOME environment to 
> SUGAR_ROOT/data).
Have you considered saving the history as part of the data store entry 
instead? That way your activity wouldn't mix histories from separate 
sessions (i.e. when debugging several different programs).

> Rainbow changes UID for every invocation [...]
Yes, that's the default behaviour. Rainbow can be instructed to use a 
constant UID (Browse does); according to the OLPC wiki [1] you'd need to 
add a file activity/, containing "constant-uid" on a 
single line.
This is the least preferable solution, though.

> Apparently the create mask rainbow uses is 755 and group members do 
> not have write access.
It's not Rainbow that decides this. Permissions of newly created file 
system entries (i.e. files and directories) are determined by the umask 
(see e.g. "man 2 umask"). You can either widen the permissions after 
creation using chmod() (see "pydoc os.chmod") or tweak the umask (see 
"pydoc os.umask"); since the latter affects _all_ created files I would 
recommend the chmod() (you could save+restore the umask, but it's prone 
to race conditions).


CU Sascha

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