Date: Tue, 03 May 2011 23:16:10 +0200 From: Uffe Jakobsen <uffe@uffe.org> To: freebsd-jail@freebsd.org Subject: Re: Getting hostname from jail_getid(3) or ezjail(5) Message-ID: <4DC0709A.4040705@uffe.org> In-Reply-To: <20110208173032.38e0a073@adolfputzen> References: <20110208173032.38e0a073@adolfputzen>
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On 2011-02-08 17:30, Julian Fagir wrote:
> Hi,
>
> I wanted to write a tool starting a shell in a jail. I know, jexec
> accomplishes this too, but I want to compile the name of the jail into the
> program, no commandline-parameters (more about this topic will be posted on
> this list soon).
> Thus, I used libjail, more specific jail_getid(3) to get the id of the jail
> and start a shell in it.
> The name of the jail is 'jail2', it was created by ezjail(5), and the
> important lines in /usr/local/etc/ezjail/jail2 are:
> export jail_jail2_hostname="zweihorn2"
> export jail_jail2_ip="IPADDRESS"
> export jail_jail22_rootdir="/usr/jails/jail2"
>
> Anyway, when starting the jail, `jls` bravely shows as the hostname of the
> jail 'jail2'.
>
> But when I compile this program (with `cc -ljail jexec_sh.c -o jexec_sh`)
>
> #include<sys/types.h>
> #include<sys/param.h>
> #include<sys/jail.h>
>
> #include<string.h>
> #include<unistd.h>
> #include<stdio.h>
> #include<jail.h>
>
> #define JAIL_NAME "jail2"
>
> int
> main(int argc, char* argv[]) {
> char *jname;
> int jid;
>
> jid = jail_getid(JAIL_NAME);
> printf("Jail 2 is running: %d\n", jid);
> jname = jail_getname(jid);
> printf("Jailname: '%s' to jid %d\n", jname, jid);
> return(0);
> }
>
> jail_getid returns -1; meaning the jailname does not exist. When setting
> JAIL_NAME to "1" (or "2", etc., according to the jid, if I restarted it), the
> jid is correctly returned:
> zweihorn1# /home/julian/jexec_sh
> Jail 1 is running: 1
> Jailname: '1' to jid 1
>
> Am i missing something? jail_getid/jail_getname should return exactly the
> output I expected?! ezjail must be setting the name right as jls returns the
> correct name. jls does nearly the same, though requesting directly the params
> without libjail, but libjail does that internally, too.
>
>
> Regards, Julian
jail_name and jail_hostname are not the same thing - jls without options
does not display jail_name only hostname - try to look at the output of
"jls -v"
This (pending) patch enabled setting of jail_name from rc.d/rc.conf
framework
http://www.freebsd.org/cgi/query-pr.cgi?pr=conf/150599
/Uffe
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