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_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.
188
189
190
191 Use of a precise exit code allows the responsible restarter to
192 categorize an error response as likely to be intermittent and worth
193 pursuing restart or permanent and request administrative intervention.
194
195 Timeouts
196 Each method can have an independent timeout, given in seconds. The
197 choice of a particular timeout should be based on site expectations for
198 detecting a method failure due to non-responsiveness. Sites with
199 replicated filesystems or other failover resources can elect to
200 lengthen method timeouts from the default. Sites with no remote
201 resources can elect to shorten the timeouts. Method timeout is
202 specified by the timeout_seconds property.
203
204
205 If you specify 0 timeout_seconds for a method, it declares to the
206 restarter that there is no timeout for the service. This setting is not
207 preferred, but is available for services that absolutely require it.
208
209
210 -1 timeout_seconds is also accepted, but is a deprecated specification.
211
212 Shell Programming Support
213 A set of environment variables that define the above exit status values
214 is provided with convenience shell functions in the file
215 /lib/svc/share/smf_include.sh. This file is a Bourne shell script
216 suitable for inclusion via the source operator in any Bourne-compatible
217 shell.
218
219
220 To assist in the composition of scripts that can serve as SMF methods
221 as well as /etc/init.d scripts, the smf_present() shell function is
222 provided. If the smf(5) facility is not available, smf_present()
223 returns a non-zero exit status.
224
225
226 One possible structure for such a script follows:
227
228 if smf_present; then
229 # Shell code to run application as managed service
230 ....
231
232 smf_clear_env
233 else
234 # Shell code to run application as /etc/init.d script
235 ....
236 fi
237
238
239
240 This example shows the use of both convenience functions that are
241 provided.
242
243 Method Context
244 The service management facility offers a common mechanism set the
245 context in which the fork(2)-exec(2) model services execute.
246
247
248 The desired method context should be provided by the service developer.
249 All service instances should run with the lowest level of privileges
250 possible to limit potential security compromises.
251
252
253 A method context can contain the following properties:
254
255 use_profile
256
257 A boolean that specifies whether the profile should be used instead
258 of the user, group, privileges, and limit_privileges properties.
259
260
261 environment
262
263 Environment variables to insert into the environment of the method,
264 in the form of a number of NAME=value strings.
265
266
267 profile
268
269 The name of an RBAC (role-based access control) profile which,
270 along with the method executable, identifies an entry in
271 exec_attr(4).
272
273
274 user
275
276 The user ID in numeric or text form.
277
278
279 group
280
281 The group ID in numeric or text form.
282
283
284 supp_groups
285
286 An optional string that specifies the supplemental group
287 memberships by ID, in numeric or text form.
288
289
290 privileges
291
292 An optional string specifying the privilege set as defined in
293 privileges(5).
294
295
296 limit_privileges
297
298 An optional string specifying the limit privilege set as defined in
299 privileges(5).
300
301
302 working_directory
303
304 The home directory from which to launch the method. :home can be
305 used as a token to indicate the home directory of the user whose
306 uid is used to launch the method. If the property is unset, :home
307 is used.
308
309
310 security_flags
311
312 The security flags to apply when launching the method. See
313 security-flags(5).
314
315
316 The "default" keyword specifies those flags specified in
317 svc:/system/process-security. The "all" keyword enables all flags,
318 the "none" keyword enables no flags. Further flags may be added by
319 specifying their name, or removed by specifying their name prefixed
320 by '-' or '!'.
321
322
323 Use of "all" has associated risks, as future versions of the system
324 may include further flags which may harm poorly implemented
325 software.
326
327
328 corefile_pattern
329
330 An optional string that specifies the corefile pattern to use for
331 the service, as per coreadm(1M). Most restarters supply a default.
332 Setting this property overrides local customizations to the global
333 core pattern.
334
335
336 project
337
338 The project ID in numeric or text form. :default can be used as a
339 token to indicate a project identified by getdefaultproj(3PROJECT)
340 for the user whose uid is used to launch the method.
341
342
343 resource_pool
344
345 The resource pool name on which to launch the method. :default can
346 be used as a token to indicate the pool specified in the project(4)
347 entry given in the project attribute above.
348
349
350
351 The method context can be set for the entire service instance by
352 specifying a method_context property group for the service or instance.
353 A method might override the instance method context by providing the
354 method context properties on the method property group.
355
356
357 Invalid method context settings always lead to failure of the method,
358 with the exception of invalid environment variables that issue
359 warnings.
360
361
362 In addition to the context defined above, many fork(2)-exec(2) model
363 restarters also use the following conventions when invoking executables
364 as methods:
365
366 Argument array
367
368 The arguments in argv[] are set consistently with the result
369 /bin/sh -c of the exec string.
370
371
372 File descriptors
373
374 File descriptor 0 is /dev/null. File descriptors 1 and 2 are
375 recommended to be a per-service log file.
376
377
378 FILES
379 /lib/svc/share/smf_include.sh
380
381 Definitions of exit status values.
382
383
384 /usr/include/libscf.h
385
386 Definitions of exit status codes.
387
388
389 SEE ALSO
390 zonename(1), coreadm(1M), inetd(1M), svccfg(1M), svc.startd(1M),
391 exec(2), fork(2), getdefaultproj(3PROJECT), exec_attr(4), project(4),
392 service_bundle(4), attributes(5), privileges(5), rbac(5), smf(5),
393 smf_bootstrap(5), zones(5), security-flags(5)
394
395 NOTES
396 The present version of smf(5) does not support multiple repositories.
397
398
399 When a service is configured to be started as root but with privileges
400 different from limit_privileges, the resulting process is privilege
401 aware. This can be surprising to developers who expect seteuid(<non-
402 zero UID>) to reduce privileges to basic or less.
403
404
405
406 May 20, 2009 SMF_METHOD(5)