LIBRARY

Lb libc

SYNOPSIS

In sys/param.h In sys/jail.h Ft int Fn jail struct jail *jail Ft int Fn jail_attach int jid Ft int Fn jail_remove int jid In sys/uio.h Ft int Fn jail_get struct iovec *iov u_int niov int flags Ft int Fn jail_set struct iovec *iov u_int niov int flags

DESCRIPTION

The Fn jail system call sets up a jail and locks the current process in it.

The argument is a pointer to a structure describing the prison:

struct jail {
        uint32_t        version;
        char            *path;
        char            *hostname;
        char            *jailname;
        unsigned int    ip4s;
        unsigned int    ip6s;
        struct in_addr  *ip4;
        struct in6_addr *ip6;
};

``version '' defines the version of the API in use. JAIL_API_VERSION is defined for the current version.

The ``path '' pointer should be set to the directory which is to be the root of the prison.

The ``hostname '' pointer can be set to the hostname of the prison. This can be changed from the inside of the prison.

The ``jailname '' pointer is an optional name that can be assigned to the jail for example for management purposes.

The ``ip4s '' and ``ip6s '' give the numbers of IPv4 and IPv6 addresses that will be passed via their respective pointers.

The ``ip4 '' and ``ip6 '' pointers can be set to an arrays of IPv4 and IPv6 addresses to be assigned to the prison, or NULL if none. IPv4 addresses must be in network byte order.

This is equivalent to the Fn jail_set system call (see below), with the parameters path host.hostname name ip4.addr and ip6.addr and with the JAIL_ATTACH flag.

The Fn jail_set system call creates a new jail, or modifies an existing one, and optionally locks the current process in it. Jail parameters are passed as an array of name-value pairs in the array Fa iov , containing Fa niov elements. Parameter names are a null-terminated string, and values may be strings, integers, or other arbitrary data. Some parameters are boolean, and do not have a value (their length is zero) but are set by the name alone with or without a ``no'' prefix, e.g. persist or nopersist Any parameters not set will be given default values, generally based on the current environment.

Jails have a set of core parameters, and modules can add their own jail parameters. The current set of available parameters, and their formats, can be retrieved via the security.jail.param sysctl MIB entry. Notable parameters include those mentioned in the Fn jail description above, as well as jid and name which identify the jail being created or modified. See jail(8) for more information on the core jail parameters.

The Fa flags arguments consists of one or more of the following flags:

JAIL_CREATE

Create a new jail. If a jid or name parameters exists, they must not refer to an existing jail.

JAIL_UPDATE

Modify an existing jail. One of the jid or name parameters must exist, and must refer to an existing jail. If both JAIL_CREATE and JAIL_UPDATE are set, a jail will be created if it does not yet exist, and modified if it does exist.

JAIL_ATTACH

In addition to creating or modifying the jail, attach the current process to it, as with the Fn jail_attach system call.

JAIL_DYING

Allow setting a jail that is in the process of being removed.

The Fn jail_get system call retrieves jail parameters, using the same name-value list as Fn jail_set in the Fa iov and Fa niov arguments. The jail to read can be specified by either jid or name by including those parameters in the list. If they are included but are not intended to be the search key, they should be cleared (zero and the empty string respectively).

The special parameter lastjid can be used to retrieve a list of all jails. It will fetch the jail with the jid above and closest to the passed value. The first jail (usually but not always jid 1) can be found by passing a lastjid of zero.

The Fa flags arguments consists of one or more following flags:

JAIL_DYING

Allow getting a jail that is in the process of being removed.

The Fn jail_attach system call attaches the current process to an existing jail, identified by Fa jid .

The Fn jail_remove system call removes the jail identified by Fa jid . It will kill all processes belonging to the jail, and remove any children of that jail.

RETURN VALUES

If successful, Fn jail , Fn jail_set , and Fn jail_get return a non-negative integer, termed the jail identifier (JID). They return -1 on failure, and set errno to indicate the error.

Rv -std jail_attach jail_remove

HISTORY

The Fn jail system call appeared in Fx 4.0 . The Fn jail_attach system call appeared in Fx 5.1 . The Fn jail_set , Fn jail_get , and Fn jail_remove system calls appeared in Fx 8.0 .

AUTHORS

The jail feature was written by An Poul-Henning Kamp for R&D Associates ``http://www.rndassociates.com/ '' who contributed it to Fx . An James Gritton added the extensible jail parameters and hierarchical jails.