Henrik Nordstrom wrote:
> > > if(fork())
> > > exit(0);
> > > close(0);
> > > open("/dev/null",O_RDONLY);
> > > setsid();
>
> > Question:
> > why do u do open(...) here?
> > thanks in advance.
>
> A stand-alone daemon should not have a terminal open as stdin, nor any
> other source as stdin. Whis is why I close filedescriptor 0.
>
> The reason why I open /dev/null is to have something open on
> filedescriptor 0. If I don't then then the first file the daemon opens
> will get filedescriptor 0 which can have bad effects...
There is a similar problem for descriptors 1 and 2, particularly in
setuid programs.
If a user runs the program with one or both of these descriptors
closed, the next file which the program opens will get one of them.
Any data written to stdout/stderr will then go to the file.
--
Glynn Clements <[EMAIL PROTECTED]>
