1 SMF_METHOD(5) Standards, Environments, and Macros SMF_METHOD(5)
2
3
4
5 NAME
6 smf_method - service management framework conventions for methods
7
8 DESCRIPTION
9 The class of services managed by svc.startd(1M) in the service
10 management framework, smf(5), consists of applications that fit a
11 simple fork(2)-exec(2) model. The svc.startd(1M) master daemon and
12 other restarters support the fork(2)-exec(2) model, potentially with
13 additional capabilities. The svc.startd(1M) daemon and other restarters
14 require that the methods which activate, manipulate, or examine a
15 service instance follow the conventions described in this manual page.
16
17 Invocation form
18 The form of a method invocation is not dictated by convention. In some
19 cases, a method invocation might consist of the direct invocation of
20 the daemon or other binary executable that provides the service. For
21 cases in which an executable script or other mediating executable is
22 used, the convention recommends the form:
23
24 /path/to/method_executable abbr_method_name
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26
27
28 The abbr_method_name used for the recommended form is a supported
29 method such as start or stop. The set of methods supported by a
30 restarter is given on the related restarter page. The svc.startd(1M)
31 daemon supports start, stop, and refresh methods.
32
33
34 A restarter might define other kinds of methods beyond those referenced
35 in this page. The conventions surrounding such extensions are defined
36 by the restarter and might not be identical to those given here.
37
38 Environment Variables
39 The restarter provides four environment variables to the method that
40 determine the context in which the method is invoked.
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42 SMF_FMRI
43
44 The service fault management resource identifier (FMRI) of the
45 instance for which the method is invoked.
46
47
48 SMF_METHOD
49
50 The full name of the method being invoked, such as start or stop.
51
52
53 SMF_RESTARTER
54
55 The service FMRI of the restarter that invokes the method
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57
58 SMF_ZONENAME
59
60 The name of the zone in which the method is running. This can also
61 be obtained by using the zonename(1) command.
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63
64
65 These variables should be removed from the environment prior to the
66 invocation of any persistent process by the method. A convenience shell
67 function, smf_clear_env, is given for service authors who use Bourne-
68 compatible shell scripting to compose service methods in the include
69 file described below.
70
71
72 The method context can cause other environment variables to be set as
73 described below.
74
75 Method Definition
76 A method is defined minimally by three properties in a propertygroup of
77 type method.
78
79
80 These properties are:
81
82 exec (astring)
83 Method executable string.
84
85
86 timeout_seconds (count)
87 Number of seconds before method times out.
88 See the Timeouts section for more detail.
89
90
91 type (astring)
92 Method type. Currently always set to method.
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94
95
96 A Method Context can be defined to further refine the execution
97 environment of the method. See the Method Context section for more
98 information.
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100 Method Tokens
101 When defined in the exec string of the method by the restarter
102 svc.startd, a set of tokens are parsed and expanded with appropriate
103 value. Other restarters might not support method tokens. The delegated
104 restarter for inet services, inetd(1M), does not support the following
105 method expansions.
106
107 %%
108
109 %
110
111
112 %r
113
114 Name of the restarter, such as svc.startd
115
116
117 %m
118
119 The full name of the method being invoked, such as start or stop.
120
121
122 %s
123
124 Name of the service
125
126
127 %i
128
129 Name of the instance
130
131
132 %f
133
134 FMRI of the instance
135
136
137 %{prop[:,]}
138
139 Value(s) of a property. The prop might be a property FMRI, a
140 property group name and a property name separated by a /, or a
141 property name in the application property group. These values can
142 be followed by a , (comma) or : (colon). If present, the separators
143 are used to separate multiple values. If absent, a space is used.
144 The following shell metacharacters encountered in string values are
145 quoted with a (backslash):
146
147 ; & ( ) | ^ < > newline space tab " '
148
149 An invalid expansion constitutes method failure.
150
151
152
153 Two explicit tokens can be used in the place of method commands.
154
155 :kill [-signal]
156
157 Sends the specified signal, which is SIGTERM by default, to all
158 processes in the primary instance contract. Always returns
159 SMF_EXIT_OK. This token should be used to replace common pkill
160 invocations.
161
162
163 :true
164
165 Always returns SMF_EXIT_OK. This token should be used for methods
166 that are required by the restarter but which are unnecessary for
167 the particular service implementation.
168
169
170 Exiting and Exit Status
171 The required behavior of a start method is to delay exiting until the
172 service instance is ready to answer requests or is otherwise
173 functional.
174
175
176 The following exit status codes are defined in <libscf.h> and in the
177 shell support file.
178
179
180
181
182 SMF_EXIT_OK 0 Method exited,
183 performing its
184 operation
185 successfully.
186 SMF_EXIT_ERR_FATAL 95 Method failed
187 fatally and is
188 unrecoverable
189 without
190 administrative
191 intervention.
192 SMF_EXIT_ERR_CONFIG 96 Unrecoverable
193 configuration
194 error. A common
195 condition that
196 returns this exit
197 status is the
198 absence of required
199 configuration files
200 for an enabled
201 service instance.
202 SMF_EXIT_MON_DEGRADE 97 Method encountered
203 some problems and
204 may not be fully
205 functional.
206 SMF_EXIT_ERR_NOSMF 99 Method has been
207 mistakenly invoked
208 outside the smf(5)
209 facility. Services
210 that depend on
211 smf(5) capabilities
212 should exit with
213 this status value.
214 SMF_EXIT_ERR_PERM 100 Method requires a
215 form of permission
216 such as file
217 access, privilege,
218 authorization, or
219 other credential
220 that is not
221 available when
222 invoked.
223 SMF_EXIT_ERR_OTHER non-zero Any non-zero exit
224 status from a
225 method is treated
226 as an unknown
227 error. A series of
228 unknown errors can
229 be diagnosed as a
230 fault by the
231 restarter or on
232 behalf of the
233 restarter.
234
235
236
237 Use of a precise exit code allows the responsible restarter to
238 categorize an error response as likely to be intermittent and worth
239 pursuing restart or permanent and request administrative intervention.
240
241 Timeouts
242 Each method can have an independent timeout, given in seconds. The
243 choice of a particular timeout should be based on site expectations for
244 detecting a method failure due to non-responsiveness. Sites with
245 replicated filesystems or other failover resources can elect to
246 lengthen method timeouts from the default. Sites with no remote
247 resources can elect to shorten the timeouts. Method timeout is
248 specified by the timeout_seconds property.
249
250
251 If you specify 0 timeout_seconds for a method, it declares to the
252 restarter that there is no timeout for the service. This setting is not
253 preferred, but is available for services that absolutely require it.
254
255
256 -1 timeout_seconds is also accepted, but is a deprecated specification.
257
258 Shell Programming Support
259 A set of environment variables that define the above exit status values
260 is provided with convenience shell functions in the file
261 /lib/svc/share/smf_include.sh. This file is a Bourne shell script
262 suitable for inclusion via the source operator in any Bourne-compatible
263 shell.
264
265
266 To assist in the composition of scripts that can serve as SMF methods
267 as well as /etc/init.d scripts, the smf_present() shell function is
268 provided. If the smf(5) facility is not available, smf_present()
269 returns a non-zero exit status.
270
271
272 One possible structure for such a script follows:
273
274 if smf_present; then
275 # Shell code to run application as managed service
276 ....
277
278 smf_clear_env
279 else
280 # Shell code to run application as /etc/init.d script
281 ....
282 fi
283
284
285
286 This example shows the use of both convenience functions that are
287 provided.
288
289 Method Context
290 The service management facility offers a common mechanism set the
291 context in which the fork(2)-exec(2) model services execute.
292
293
294 The desired method context should be provided by the service developer.
295 All service instances should run with the lowest level of privileges
296 possible to limit potential security compromises.
297
298
299 A method context can contain the following properties:
300
301 use_profile
302
303 A boolean that specifies whether the profile should be used instead
304 of the user, group, privileges, and limit_privileges properties.
305
306
307 environment
308
309 Environment variables to insert into the environment of the method,
310 in the form of a number of NAME=value strings.
311
312
313 profile
314
315 The name of an RBAC (role-based access control) profile which,
316 along with the method executable, identifies an entry in
317 exec_attr(4).
318
319
320 user
321
322 The user ID in numeric or text form.
323
324
325 group
326
327 The group ID in numeric or text form.
328
329
330 supp_groups
331
332 An optional string that specifies the supplemental group
333 memberships by ID, in numeric or text form.
334
335
336 privileges
337
338 An optional string specifying the privilege set as defined in
339 privileges(5).
340
341
342 limit_privileges
343
344 An optional string specifying the limit privilege set as defined in
345 privileges(5).
346
347
348 working_directory
349
350 The home directory from which to launch the method. :home can be
351 used as a token to indicate the home directory of the user whose
352 uid is used to launch the method. If the property is unset, :home
353 is used.
354
355
356 security_flags
357
358 The security flags to apply when launching the method. See
359 security-flags(5).
360
361
362 The "default" keyword specifies those flags specified in
363 svc:/system/process-security. The "all" keyword enables all flags,
364 the "none" keyword enables no flags. The "current" keyword
365 specifies the current flags. Flags may be added by specifying
366 their name (optionally preceded by '+'), and removed by preceding
367 their name with '-').
368
369
370 Use of "all" has associated risks, as future versions of the system
371 may include further flags which may harm poorly implemented
372 software.
373
374
375 corefile_pattern
376
377 An optional string that specifies the corefile pattern to use for
378 the service, as per coreadm(1M). Most restarters supply a default.
379 Setting this property overrides local customizations to the global
380 core pattern.
381
382
383 project
384
385 The project ID in numeric or text form. :default can be used as a
386 token to indicate a project identified by getdefaultproj(3PROJECT)
387 for the user whose uid is used to launch the method.
388
389
390 resource_pool
391
392 The resource pool name on which to launch the method. :default can
393 be used as a token to indicate the pool specified in the project(4)
394 entry given in the project attribute above.
395
396
397
398 The method context can be set for the entire service instance by
399 specifying a method_context property group for the service or instance.
400 A method might override the instance method context by providing the
401 method context properties on the method property group.
402
403
404 Invalid method context settings always lead to failure of the method,
405 with the exception of invalid environment variables that issue
406 warnings.
407
408
409 In addition to the context defined above, many fork(2)-exec(2) model
410 restarters also use the following conventions when invoking executables
411 as methods:
412
413 Argument array
414
415 The arguments in argv[] are set consistently with the result
416 /bin/sh -c of the exec string.
417
418
419 File descriptors
420
421 File descriptor 0 is /dev/null. File descriptors 1 and 2 are
422 recommended to be a per-service log file.
423
424
425 FILES
426 /lib/svc/share/smf_include.sh
427
428 Definitions of exit status values.
429
430
431 /usr/include/libscf.h
432
433 Definitions of exit status codes.
434
435
436 SEE ALSO
437 zonename(1), coreadm(1M), inetd(1M), svccfg(1M), svc.startd(1M),
438 exec(2), fork(2), getdefaultproj(3PROJECT), exec_attr(4), project(4),
439 service_bundle(4), attributes(5), privileges(5), rbac(5), smf(5),
440 smf_bootstrap(5), zones(5), security-flags(5)
441
442 NOTES
443 The present version of smf(5) does not support multiple repositories.
444
445
446 When a service is configured to be started as root but with privileges
447 different from limit_privileges, the resulting process is privilege
448 aware. This can be surprising to developers who expect seteuid(<non-
449 zero UID>) to reduce privileges to basic or less.
450
451
452
453 December 4, 2017 SMF_METHOD(5)