Any race conditions involved on adding/mod users from differentprocesses

Hi,

If I am adding or modifying users -useradd,usermod(entries in /etc/
passwd) simultaneously from different processes, Is it safe to do
that ?. Does linux internally take care of all race conditions ?

Thanks
Reji Thomas

Reji <rejithomas.d@gmail.com> wrote:[color=blue]
> Hi,
>
> If I am adding or modifying users -useradd,usermod(entries in /etc/
> passwd) simultaneously from different processes, Is it safe to do
> that ?. Does linux internally take care of all race conditions ?
>
> Thanks
> Reji Thomas[/color]

There is no control on race conditions.

Reji wrote:[color=blue]
> Hi,
>
> If I am adding or modifying users -useradd,usermod(entries in /etc/
> passwd) simultaneously from different processes, Is it safe to do
> that ?. Does linux internally take care of all race conditions ?
>
> Thanks
> Reji Thomas[/color]

All? No. But by using useradd, it provides lockfiles that help protect you
from conflicts.