smf_method - service management framework conventions for methods
The class of services managed by svc.startd
(1M) in the service management
(5), consists of applications that fit a simple
(2) model. The svc.startd
(1M) master daemon
and other restarters support the fork
potentially with additional capabilities. The svc.startd
(1M) daemon and
other restarters require that the methods which activate, manipulate, or
examine a service instance follow the conventions described in this manual
The form of a method invocation is not dictated by convention. In some cases, a
method invocation might consist of the direct invocation of the daemon or
other binary executable that provides the service. For cases in which an
executable script or other mediating executable is used, the convention
recommends the form:
used for the recommended form is a supported method
such as start
. The set of methods supported by a
restarter is given on the related restarter page. The svc.startd
daemon supports start
, and refresh
A restarter might define other kinds of methods beyond those referenced in this
page. The conventions surrounding such extensions are defined by the restarter
and might not be identical to those given here.
The restarter provides four environment variables to the method that determine
the context in which the method is invoked.
The service fault management resource
identifier (FMRI) of the instance for which the method is invoked.
The full name of the method being invoked,
such as start or stop.
The service FMRI of the restarter that invokes
The name of the zone in which the method is
running. This can also be obtained by using the zonename(1)
These variables should be removed from the environment prior to the invocation
of any persistent process by the method. A convenience shell function,
, is given for service authors who use Bourne-compatible
shell scripting to compose service methods in the include file described
The method context can cause other environment variables to be set as described
A method is defined minimally by three properties in a propertygroup of type
These properties are:
Method executable string.
Number of seconds before method times out.
See the Timeouts section for more detail.
Method type. Currently always set to
A Method Context can be defined to further refine the execution environment of
the method. See the Method Context
section for more information.
When defined in the exec
string of the method by the restarter
, a set of tokens are parsed and expanded with appropriate
value. Other restarters might not support method tokens. The delegated
restarter for inet services, inetd
(1M), does not support the following
Name of the restarter, such as
The full name of the method being invoked,
such as start or stop.
Name of the service
Name of the instance
FMRI of the instance
Value(s) of a property. The prop
be a property FMRI, a property group name and a property name separated by a
, or a property name in the application
property group. These
values can be followed by a ,
(comma) or :
(colon). If present,
the separators are used to separate multiple values. If absent, a space is
used. The following shell metacharacters encountered in string values are
quoted with a (backslash):
; & ( ) | ^ < > newline space tab " '
An invalid expansion constitutes method failure.
Two explicit tokens can be used in the place of method commands.
Sends the specified signal, which is
SIGTERM by default, to all processes in the primary instance contract.
Always returns SMF_EXIT_OK. This token should be used to replace common
Always returns SMF_EXIT_OK. This token
should be used for methods that are required by the restarter but which are
unnecessary for the particular service implementation.
The required behavior of a start method is to delay exiting until the service
instance is ready to answer requests or is otherwise functional.
The following exit status codes are defined in <libscf.h>
the shell support file.
||Method exited, performing its operation successfully.
||Method failed fatally and is unrecoverable without administrative
||Unrecoverable configuration error. A common condition that returns this
exit status is the absence of required configuration files for an enabled
||Method encountered some problems and may not be fully functional.
||Method has been mistakenly invoked outside the smf(5) facility.
Services that depend on smf(5) capabilities should exit with this
||Method requires a form of permission such as file access, privilege,
authorization, or other credential that is not available when
||Any non-zero exit status from a method is treated as an unknown error. A
series of unknown errors can be diagnosed as a fault by the restarter or
on behalf of the restarter.
Use of a precise exit code allows the responsible restarter to categorize an
error response as likely to be intermittent and worth pursuing restart or
permanent and request administrative intervention.
Each method can have an independent timeout, given in seconds. The choice of a
particular timeout should be based on site expectations for detecting a method
failure due to non-responsiveness. Sites with replicated filesystems or other
failover resources can elect to lengthen method timeouts from the default.
Sites with no remote resources can elect to shorten the timeouts. Method
timeout is specified by the timeout_seconds
If you specify 0 timeout_seconds
for a method, it declares to the
restarter that there is no timeout for the service. This setting is not
preferred, but is available for services that absolutely require it.
is also accepted, but is a deprecated specification.
A set of environment variables that define the above exit status values is
provided with convenience shell functions in the file
. This file is a Bourne shell script
suitable for inclusion via the source operator in any Bourne-compatible shell.
To assist in the composition of scripts that can serve as SMF methods as well as
scripts, the smf_present()
shell function is
provided. If the smf
(5) facility is not available, smf_present()
returns a non-zero exit status.
One possible structure for such a script follows:
if smf_present; then
# Shell code to run application as managed service
# Shell code to run application as /etc/init.d script
This example shows the use of both convenience functions that are provided.
The service management facility offers a common mechanism set the context in
which the fork
(2) model services execute.
The desired method context should be provided by the service developer. All
service instances should run with the lowest level of privileges possible to
limit potential security compromises.
A method context can contain the following properties:
A boolean that specifies whether the profile
should be used instead of the user, group, privileges,
and limit_privileges properties.
Environment variables to insert into the
environment of the method, in the form of a number of NAME=value
The name of an RBAC (role-based access
control) profile which, along with the method executable, identifies an entry
The user ID in numeric or text form.
The group ID in numeric or text form.
An optional string that specifies the
supplemental group memberships by ID, in numeric or text form.
An optional string specifying the privilege
set as defined in privileges(5).
An optional string specifying the limit
privilege set as defined in privileges(5).
The home directory from which to launch the
method. :home can be used as a token to indicate the home directory of
the user whose uid is used to launch the method. If the property is
unset, :home is used.
The security flags to apply when launching the
method. See security-flags
The "default" keyword specifies those flags specified in
. The "all" keyword enables all
flags, the "none" keyword enables no flags. The "current"
keyword specifies the current flags. Flags may be added by specifying their
name (optionally preceded by '+'), and removed by preceding their name with
Use of "all" has associated risks, as future versions of the system
may include further flags which may harm poorly implemented software.
An optional string that specifies the corefile
pattern to use for the service, as per coreadm(1M). Most restarters
supply a default. Setting this property overrides local customizations to the
global core pattern.
The project ID in numeric or text form.
:default can be used as a token to indicate a project identified by
getdefaultproj(3PROJECT) for the user whose uid is used to
launch the method.
The resource pool name on which to launch the
method. :default can be used as a token to indicate the pool specified
in the project(4) entry given in the project attribute
The method context can be set for the entire service instance by specifying a
property group for the service or instance. A method
might override the instance method context by providing the method context
properties on the method property group.
Invalid method context settings always lead to failure of the method, with the
exception of invalid environment variables that issue warnings.
In addition to the context defined above, many fork
model restarters also use the following conventions when invoking executables
The arguments in argv are set
consistently with the result /bin/sh -c of the exec
File descriptor 0 is /dev/null.
File descriptors 1 and 2 are recommended to be a per-service log
Definitions of exit status values.
Definitions of exit status codes.
The present version of smf
(5) does not support multiple repositories.
When a service is configured to be started as root but with privileges different
, the resulting process is privilege aware. This
can be surprising to developers who expect seteuid(<non-zero
to reduce privileges to basic or less.