smf_method(5)						Standards, Environments, and Macros					     smf_method(5)

NAME

       smf_method - service management framework conventions for methods

DESCRIPTION

       The  class  of  services  managed by svc.startd(1M) in the service management framework, smf(5), consists of applications that fit a simple
       fork(2)-exec(2) model. The svc.startd(1M) master daemon and other restarters support the fork(2)-exec(2) model, 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 page.

   Invocation form
       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:

	 /path/to/method_executable abbr_method_name

       The abbr_method_name used for the recommended form is a supported method such as start or stop. The set of methods supported by a restarter
       is given on the related restarter page. The svc.startd(1M) daemon supports start, stop, and refresh methods.

       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.

   Environment Variables
       The restarter provides four environment variables to the method that determine the context in which the method is invoked.

       SMF_FMRI

	   The service fault management resource identifier (FMRI) of the instance for which the method is invoked.

       SMF_METHOD

	   The full name of the method being invoked, such as start or stop.

       SMF_RESTARTER

	   The service FMRI of the restarter that invokes the method

       SMF_ZONENAME

	   The name of the zone in which the method is running. This can also be obtained by using the zonename(1) command.

       These variables should be removed from the environment prior to the invocation of any persistent process by the method. A convenience shell
       function,  smf_clear_env,  is given for service authors who use Bourne-compatible shell scripting to compose service methods in the include
       file described below.

       The method context can cause other environment variables to be set as described below.

   Method Definition
       A method is defined minimally by three properties in a propertygroup of type method.

       These properties are:

       exec (astring)		  Method executable string.

       timeout_seconds (count)	  Number of seconds before method times out. See the Timeouts section for more detail.

       type (astring)		  Method type. Currently always set to method.

       A Method Context can be defined to further refine the execution environment of the method. See the Method Context section for more informa-
       tion.

   Method Tokens
       When  defined in the exec string of the method by the restarter svc.startd, 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
       method expansions.

       %%

	   %

       %r

	   Name of the restarter, such as svc.startd

       %m

	   The full name of the method being invoked, such as start or stop.

       %s

	   Name of the service

       %i

	   Name of the instance

       %f

	   FMRI of the instance

       %{prop[:,]}

	   Value(s)  of  a  property. The prop might 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.

       :kill [-signal]

	   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 pkill invocations.

       :true

	   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.

   Exiting and Exit Status
       The required behavior of a start method is to delay exiting until the service instance is ready to answer requests or  is  otherwise  func-
       tional.

       The following exit status codes are defined in <libscf.h> and in the shell support file.

       SMF_EXIT_OK	     0		 Method exited, performing its
					 operation successfully.
       SMF_EXIT_ERR_FATAL    95 	 Method failed fatally and  is
					 unrecoverable	without admin-
					 istrative intervention.
       SMF_EXIT_ERR_CONFIG   96 	 Unrecoverable	 configuration
					 error.   A  common  condition
					 that returns this exit status
					 is  the  absence  of required
					 configuration	files  for  an
					 enabled service instance.
       SMF_EXIT_ERR_NOSMF    99 	 Method  has  been  mistakenly
					 invoked  outside  the	smf(5)
					 facility.    Services	  that
					 depend on smf(5) capabilities
					 should  exit with this status
					 value.
       SMF_EXIT_ERR_PERM     100	 Method  requires  a  form  of
					 permission   such   as   file
					 access, privilege, authoriza-
					 tion,	 or  other  credential
					 that is  not  available  when
					 invoked.
       SMF_EXIT_ERR_OTHER    non-zero	 Any non-zero exit status from
					 a method  is  treated	as  an
					 unknown  error.  A  series of
					 unknown errors can  be  diag-
					 nosed	 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.

   Timeouts
       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 property.

       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.

       -1 timeout_seconds is also accepted, but is a deprecated specification.

   Shell Programming Support
       A set of environment variables that define the above exit  status  values  is  provided	with  convenience  shell  functions  in  the  file
       /lib/svc/share/smf_include.sh.  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 /etc/init.d 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
	       ....

	       smf_clear_env
	 else
	       # Shell code to run application as /etc/init.d script
	       ....
	 fi

       This example shows the use of both convenience functions that are provided.

   Method Context
       The service management facility offers a common mechanism set the context in which the fork(2)-exec(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 privi-
       leges possible to limit potential security compromises.

       A method context can contain the following properties:

       use_profile

	   A boolean that specifies whether the profile should be used instead of the user, group, privileges, and limit_privileges properties.

       environment

	   Environment variables to insert into the environment of the method, in the form of a number of NAME=value strings.

       profile

	   The name of an RBAC (role-based access control) profile which, along with the method executable, identifies an entry in exec_attr(4).

       user

	   The user ID in numeric or text form.

       group

	   The group ID in numeric or text form.

       supp_groups

	   An optional string that specifies the supplemental group memberships by ID, in numeric or text form.

       privileges

	   An optional string specifying the privilege set as defined in privileges(5).

       limit_privileges

	   An optional string specifying the limit privilege set as defined in privileges(5).

       working_directory

	   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.

       corefile_pattern

	   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.

       project

	   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.

       resource_pool

	   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 above.

       The method context can be set for the entire service instance by specifying a method_context 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 warn-
       ings.

       In addition to the context defined above, many fork(2)-exec(2) model restarters also use the following conventions when	invoking  executa-
       bles as methods:

       Argument array

	   The arguments in argv[] are set consistently with the result /bin/sh -c of the exec string.

       File descriptors

	   File descriptor 0 is /dev/null. File descriptors 1 and 2 are recommended to be a per-service log file.

FILES

       /lib/svc/share/smf_include.sh

	   Definitions of exit status values.

       /usr/include/libscf.h

	   Definitions of exit status codes.

SEE ALSO

       zonename(1), coreadm(1M), inetd(1M), svccfg(1M), svc.startd(1M), exec(2), fork(2), getdefaultproj(3PROJECT), exec_attr(4), project(4), ser-
       vice_bundle(4), attributes(5), privileges(5), rbac(5), smf(5), smf_bootstrap(5), zones(5)

NOTES

       The present version of smf(5) does not support multiple repositories.

SunOS 5.11							    3 May 2008							     smf_method(5)