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
25
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.
41
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
56
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.
62
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.
93
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.
99
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, performing its operation successfully.
183 SMF_EXIT_ERR_FATAL 95 Method failed fatally and is unrecoverable without administrative intervention.
184 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.
185 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.
186 SMF_EXIT_ERR_PERM 100 Method requires a form of permission such as file access, privilege, authorization, or other credential that is not available when invoked.
187 SMF_EXIT_TEMP_TRANSIENT 101 Method that is normally non-transient is temporarily transient. This is not an error condition and a service returning this value will not be restarted.
188 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 diagnosed as a fault by the restarter or on behalf of the restarter.
189
190
191
192 Use of a precise exit code allows the responsible restarter to
193 categorize an error response as likely to be intermittent and worth
194 pursuing restart or permanent and request administrative intervention.
195
196 Timeouts
197 Each method can have an independent timeout, given in seconds. The
198 choice of a particular timeout should be based on site expectations for
199 detecting a method failure due to non-responsiveness. Sites with
200 replicated filesystems or other failover resources can elect to
201 lengthen method timeouts from the default. Sites with no remote
202 resources can elect to shorten the timeouts. Method timeout is
203 specified by the timeout_seconds property.
204
205
206 If you specify 0 timeout_seconds for a method, it declares to the
207 restarter that there is no timeout for the service. This setting is not
208 preferred, but is available for services that absolutely require it.
209
210
211 -1 timeout_seconds is also accepted, but is a deprecated specification.
212
213 Shell Programming Support
214 A set of environment variables that define the above exit status values
215 is provided with convenience shell functions in the file
216 /lib/svc/share/smf_include.sh. This file is a Bourne shell script
217 suitable for inclusion via the source operator in any Bourne-compatible
218 shell.
219
220
221 To assist in the composition of scripts that can serve as SMF methods
222 as well as /etc/init.d scripts, the smf_present() shell function is
223 provided. If the smf(5) facility is not available, smf_present()
224 returns a non-zero exit status.
225
226
227 One possible structure for such a script follows:
228
229 if smf_present; then
230 # Shell code to run application as managed service
231 ....
232
233 smf_clear_env
234 else
235 # Shell code to run application as /etc/init.d script
236 ....
237 fi
238
239
240
241 This example shows the use of both convenience functions that are
242 provided.
243
244 Method Context
245 The service management facility offers a common mechanism set the
246 context in which the fork(2)-exec(2) model services execute.
247
248
249 The desired method context should be provided by the service developer.
250 All service instances should run with the lowest level of privileges
251 possible to limit potential security compromises.
252
253
254 A method context can contain the following properties:
255
256 use_profile
257
258 A boolean that specifies whether the profile should be used instead
259 of the user, group, privileges, and limit_privileges properties.
260
261
262 environment
263
264 Environment variables to insert into the environment of the method,
265 in the form of a number of NAME=value strings.
266
267
268 profile
269
270 The name of an RBAC (role-based access control) profile which,
271 along with the method executable, identifies an entry in
272 exec_attr(4).
273
274
275 user
276
277 The user ID in numeric or text form.
278
279
280 group
281
282 The group ID in numeric or text form.
283
284
285 supp_groups
286
287 An optional string that specifies the supplemental group
288 memberships by ID, in numeric or text form.
289
290
291 privileges
292
293 An optional string specifying the privilege set as defined in
294 privileges(5).
295
296
297 limit_privileges
298
299 An optional string specifying the limit privilege set as defined in
300 privileges(5).
301
302
303 working_directory
304
305 The home directory from which to launch the method. :home can be
306 used as a token to indicate the home directory of the user whose
307 uid is used to launch the method. If the property is unset, :home
308 is used.
309
310
311 security_flags
312
313 The security flags to apply when launching the method. See
314 security-flags(5).
315
316
317 The "default" keyword specifies those flags specified in
318 svc:/system/process-security. The "all" keyword enables all flags,
319 the "none" keyword enables no flags. The "current" keyword
320 specifies the current flags. Flags may be added by specifying
321 their name (optionally preceded by '+'), and removed by preceding
322 their name with '-').
323
324
325 Use of "all" has associated risks, as future versions of the system
326 may include further flags which may harm poorly implemented
327 software.
328
329
330 corefile_pattern
331
332 An optional string that specifies the corefile pattern to use for
333 the service, as per coreadm(1M). Most restarters supply a default.
334 Setting this property overrides local customizations to the global
335 core pattern.
336
337
338 project
339
340 The project ID in numeric or text form. :default can be used as a
341 token to indicate a project identified by getdefaultproj(3PROJECT)
342 for the user whose uid is used to launch the method.
343
344
345 resource_pool
346
347 The resource pool name on which to launch the method. :default can
348 be used as a token to indicate the pool specified in the project(4)
349 entry given in the project attribute above.
350
351
352
353 The method context can be set for the entire service instance by
354 specifying a method_context property group for the service or instance.
355 A method might override the instance method context by providing the
356 method context properties on the method property group.
357
358
359 Invalid method context settings always lead to failure of the method,
360 with the exception of invalid environment variables that issue
361 warnings.
362
363
364 In addition to the context defined above, many fork(2)-exec(2) model
365 restarters also use the following conventions when invoking executables
366 as methods:
367
368 Argument array
369
370 The arguments in argv[] are set consistently with the result
371 /bin/sh -c of the exec string.
372
373
374 File descriptors
375
376 File descriptor 0 is /dev/null. File descriptors 1 and 2 are
377 recommended to be a per-service log file.
378
379
380 FILES
381 /lib/svc/share/smf_include.sh
382
383 Definitions of exit status values.
384
385
386 /usr/include/libscf.h
387
388 Definitions of exit status codes.
389
390
391 SEE ALSO
392 zonename(1), coreadm(1M), inetd(1M), svccfg(1M), svc.startd(1M),
393 exec(2), fork(2), getdefaultproj(3PROJECT), exec_attr(4), project(4),
394 service_bundle(4), attributes(5), privileges(5), rbac(5), smf(5),
395 smf_bootstrap(5), zones(5), security-flags(5)
396
397 NOTES
398 The present version of smf(5) does not support multiple repositories.
399
400
401 When a service is configured to be started as root but with privileges
402 different from limit_privileges, the resulting process is privilege
403 aware. This can be surprising to developers who expect seteuid(<non-
404 zero UID>) to reduce privileges to basic or less.
405
406
407
408 March 2, 2017 SMF_METHOD(5)