create an empty jail with libjail

[joris dedieu]

2012/10/5 joris dedieu <joris.dedieu at gmail.com>:
> Hi,
> I try to create an empty jail using libjail. Something equivalent to
> "jail -c name=empty host.hostname=empty path=/var/empty persist". I've
> tried with jailparam_import and jail_setv on 8.3 and 9.1 but both
> failed. I can't find where my code is wrong.
>
> Eg 1:
>
> #include <sys/param.h>
> #include <sys/jail.h>
> #include <jail.h>
>
> int
> main(int argc, char **argv)
> {
>         struct jailparam params[4];
>         int jid;
>         jailparam_init(&params[0], "name");
>         jailparam_import(&params[0], "empty");
>         jailparam_init(&params[1], "host.hostname");
>         jailparam_import(&params[1], "empty.rmdir.fr");
>         jailparam_init(&params[2], "path");
>         jailparam_import(&params[2], "/var/empty");
>         /*jailparam_init(&params[3], "persist");
>         jailparam_import(&params[3], NULL);*/
>
>         if((jid = jailparam_set(params, 4, JAIL_CREATE)) == -1)
>                 err(1, "jailparam_set");
>         printf("jid is %d", jid);
>         return 0;
> }

The problem with this code (except the comments) was in my world. It
works fot me after reinstalling the libc.
The second code (with jail_setv, still not working). I will try to
find what's wrong with it.

Joris
>
>
>  jailparam_import fails with EINVAL  (from libc's jail_set but i don't
> know why)
>
>
> Eg 2:
>
> #include <sys/param.h>
> #include <sys/jail.h>
> #include <jail.h>
>
> int
> main(int argc, char **argv)
> {
>         int jid;
>         if((jid = jail_setv(JAIL_CREATE,
>                         "name", "empty"
>                         "host.hostname", "empty",
>                         "path", "/var/empty",
>                         "persist", NULL, NULL
>                         )) == -1)
>                 err(1, "jail_setv");
>         printf("jid is %d", jid);
>         return 0;
> }
>
> jail_setv fails with ENOENT. I think it comes from  libjail's
> jailparam_type as persist is not in security.jail.param's mib in
> prison 0 (see .lib/libjail/jail.c:854).
>
>
> I really don't understand why it doesn't work. If someone could have a
> little look, it would be grate.
>
> Regards
> Joris