Init.c, making it chroot

[Erik Udo]

That's nice. But NetBSDs init.c executes /etc/rc before calling 
chroot(), and that's what i'm looking for, and for a moment tried to 
implement, but i'm not very familiar with FreeBSD code :)

For example that kenv() came to me as a suprise. I'll have to try to 
implement the NetBSD way where /etc/rc is executed before chroot(). 
Ofcourse now that i dont have to use sysctls, it's alot easier.

M. Warner Losh wrote:
> BTW, here's a patch to test.  Since FreeBSD has kenv(2), the patch is
> actually very small.
> 
> Warner
> 
> 
> 
> ------------------------------------------------------------------------
> 
> Index: init.c
> ===================================================================
> RCS file: /cache/ncvs/src/sbin/init/init.c,v
> retrieving revision 1.62
> diff -u -r1.62 init.c
> --- init.c	8 Jun 2006 14:04:36 -0000	1.62
> +++ init.c	28 Dec 2006 20:39:33 -0000
> @@ -55,6 +55,7 @@
>  #include <db.h>
>  #include <errno.h>
>  #include <fcntl.h>
> +#include <kenv.h>
>  #include <libutil.h>
>  #include <paths.h>
>  #include <signal.h>
> @@ -187,6 +188,7 @@
>  int
>  main(int argc, char *argv[])
>  {
> +	char init_chroot[PATH_MAX];
>  	int c;
>  	struct sigaction sa;
>  	sigset_t mask;
> @@ -239,6 +241,12 @@
>  	 */
>  	openlog("init", LOG_CONS|LOG_ODELAY, LOG_AUTH);
>  
> +	*init_chroot = '\0';
> +	kenv(KENV_GET, "init_chroot", init_chroot, sizeof(init_chroot));
> +	if (*init_chroot)
> +		if (chdir(init_chroot) != 0 || chroot(".") != 0)
> +			warning("Can't chroot to %s: %m", init_chroot);
> +
>  	/*
>  	 * Create an initial session.
>  	 */