DESCRIPTION
The
/system/contract file system acts as the primary interface to the contract subsystem. There is a subdirectory of
/system/contract for each available contract type.
/system/contract can be mounted on any mount point, in addition to the standard
/system/contract mount point, and can be mounted several places at once. Such additional mounts are allowed in order to facilitate the confinement of processes to subtrees of the file system using
chroot(1M) and yet allow such processes to continue to use contract commands and interfaces.
A combination of standard system calls (for example,
open(2),
close(2), and
poll(2)) and calls to
libcontract(3LIB) access
/system/contract files.
Consumers of the contract file system must be large file aware. See
largefile(5) and
lfcompile64(5).
DIRECTORY STRUCTURE
At the top level, the /system/contract directory contains subdirectories named with each available contract type, and one special directory, all. Each of these directories is world-readable and world-searchable.
STRUCTURE OF /system/contract/type
Each
/system/contract/type directory contains a fixed number of files. It also contains a variable number of subdirectories corresponding to existing contracts of type
type and named with the decimal representation of the contracts' IDs.
The following files are in a
/system/contract/type directory:
template
Opening this file returns a file descriptor for a new
type contract template.
You can use the following
libcontract(3LIB) calls on a template file descriptor:
>
ct_tmpl_activate(3contract)
ct_tmpl_clear(3contract)
ct_tmpl_create(3contract)
See TERMS for additional template functions.
latest
Opening this file returns a file descriptor for the status file of the last type contract written by the opening LWP. See STRUCTURE OF /system/contract/type/id. If the opening LWP has not created a type contract, opening latest fails with ESRCH.
bundle
Opening this file returns a file descriptor for an event endpoint which receives events from all type contracts on the system. No privileges are required to open a type bundle event endpoint. Events sent by contracts owned and written by users other than the reader's effective user id are invisible, that is, they are silently skipped, unless the reader has {PRIV_CONTRACT_OBSERVER} in its effective set. See EVENTS.
pbundle
Opening this file returns a file descriptor for an event endpoint which receives events from all type contracts held by the opening process. See EVENTS.
STRUCTURE OF /system/contract/all
The /system/contract/all directory contains a numerically named file for each contract in the system. Each file is a symbolic link to the type-specific directory for that contract, that is /system/contract/all/id points to /system/contract/type/id.
STRUCTURE OF /system/contract/type/id
Each
/system/contract/type/
id directory contains the following files:
ctl
Opening this file returns a file descriptor for contract
id's control file. The open fails if the opening process does not hold contract
id and the contract has not been inherited by the process contract of which the opening process is a member. See
process(4).
The following
libcontract(3LIB) calls can be made on a
ctl file descriptor if the contract is owned by the caller:
ct_ctl_abandon(3contract)
ct_ctl_newct(3contract)
ct_ctl_ack(3contract)
ct_ctl_qack(3contract)
The following
libcontract(3LIB) call can be made on a ctl file descriptor if the contract doesn't have an owner:
ct_ctl_adopt(3contract)
status
Opening this file returns a file descriptor for contract
id's status file. The following
libcontract(3LIB) calls can be made on a status file descriptor:
ct_status_read(3contract)
See STATUS.
events
Opening this file returns a file descriptor for an event endpoint which receives events from contract
id. See
EVENTS.
Only a process which has the same effective user ID as the process owning the contract, the same effective user ID as the contract's author, or has
{PRIV_CONTRACT_OBSERVER} in its effective set can open the event endpoint for a contract.
TERMS
The following terms are defined for all contracts:
cookie
Specifies a 64-bit quantity that the contract author can use to identify the contract. Use ct_tmpl_set_cookie(3CONTRACT) to set this term.
informative event set
Selects which events are delivered as informative events. Use ct_tmpl_set_informative(3CONTRACT) to set this term.
critical event set
Selects which events are delivered as critical events. Use ct_tmpl_set_critical(3CONTRACT) to set this term.
STATUS
A status object returned by
ct_status_read(3CONTRACT) contains the following pieces of information:
contract ID
The numeric ID of the contract. Use ct_status_get_id(3CONTRACT) to obtain this information.
contract type
The type of the contract, specified as a string. Obtained using ct_status_get_type(3CONTRACT). The contract type is the same as its subdirectory name under /system/contract.
creator's zone ID
The zone ID of the process which created the contract. Obtained using ct_status_get_zoneid(3CONTRACT).
ownership state
The state of the contract, specified as CTS_OWNED, CTS_INHERITED, CTS_ORPHAN, or CTS_DEAD. Use ct_status_get_state(3CONTRACT) to obtain this information.
contract holder
If the contract's state is CTS_OWNED, the ID of the process which owns the contract. If the contract's state is CTS_INHERITED, the ID of the contract which is acting as regent. If the contract's state is CTS_ORPHAN or CTS_DEAD, this is undefined. Use ct_status_get_holder(3CONTRACT) to obtain this information.
number of critical events
The number of unacknowledged critical events pending on the contract's event queue. Use ct_status_get_nevents(3CONTRACT) to obtain this information.
negotiation time
The time remaining before the current synchronous negotiation times out. Use ct_status_get_ntime(3CONTRACT) to obtain this information.
negotiation quantum time
The time remaining before the current negotiation quantum runs out. Use ct_status_get_qtime(3CONTRACT) to obtain this information.
negotiation event ID
The ID of the event which initiated the negotiation timeout. Use ct_status_get_nevid(3CONTRACT) to obtain this information.
cookie (term)
The contract's cookie term. Use ct_status_get_cookie(3CONTRACT) to obtain this information.
Informative event set (term)
The contract's informative event set. Use ct_status_get_informative(3CONTRACT) to obtain this information.
Critical event set (term)
The contract's critical event set. Use ct_status_get_critical(3CONTRACT) to obtain this information.
EVENTS
All three event endpoints,
/system/contract/type/bundle,
/system/contract/type/pbundle, and
/system/contract/type/
id/events, are accessed in the same manner.
The following
libcontract(3LIB) interfaces are used with an event endpoint file descriptor:
ct_event_read(3contract)
ct_event_read_critical(3contract)
ct_event_reset(3contract)
To facilitate processes watching multiple event endpoints, it is possible to poll(2) on event endpoints. When it is possible to receive on an endpoint file descriptor, POLLIN is set for that descriptor.
An event object returned by
ct_event_read(3CONTRACT) contains the following information:
contract ID
The ID of the contract that generated the event. Use ct_event_read(3CONTRACT) to obtain this information.
event ID
The ID of the contract event.Use ct_event_get_evid(3CONTRACT).
flags
A bit vector possibly including CT_ACK and CTE_INFO. Use ct_event_get_flags(3CONTRACT) to obtain this information.
event type
The type of event, equal to one of the constants specified in the contract type's manual page or CT_EV_NEGEND. Use ct_event_get_type(3CONTRACT) to obtain this information.
EVENT TYPES
The following event types are defined:
CT_EV_NEGEND
Some time after an exit negotiation is initiated, the
CT_EV_NEGEND event is sent. This indicates that the negotiation ended. This might be because the operation was cancelled, or because the operation was successful. If successful, and the owner requested that a new contract be written, this contains the ID of that contract.
CT_EV_NEGEND cannot be included in a contract's informative or critical event set. It is always delivered and always critical. If
CT_EV_NEGEND indicates that the operation was successful, no further events are sent. The contract's owner should use
ct_ctl_abandon(3CONTRACT) to abandon the contract.
A
CT_EV_NEGEND event contains:
negotiation ID
The ID of the negotiation which ended. Use ct_event_get_nevid(3CONTRACT) to obain this information.
new contract ID
The ID of the newly created contract. This value is 0 if no contract was created, or the ID of the existing contract if the operation was not completed. Use ct_event_get_newct(3CONTRACT) to obtain this information.
FILES
/system/contract
List of all contract types
/system/contract/all
Directory of all contract IDs
/system/contract/all/id
Symbolic link to the type-specific directory of contract id
/system/contract/type
Specific type directory
/system/contract/type/template
Template for the contract type
/system/contract/type/bundle
Listening point for all contracts of that type
/system/contract/type/pbundle
Listening point for all contracts of that type for the opening process
/system/contract/type /latest
Status of most recent type contract created by the opening LWP
/system/contract/type/
ID
Directory for contract id
/system/contract/type/
ID/events
Listening point for contract id's events
/system/contract/type/
ID/ctl
Control file for contract ID
/system/contract/type/
ID/status
Status info for contract ID