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Code review comments from jeffpc
7029 want per-process exploit mitigation features (secflags)
7030 want basic address space layout randomization (aslr)
7031 noexec_user_stack should be a secflag
7032 want a means to forbid mappings around NULL.
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--- old/usr/src/man/man5/smf_method.5.man.txt
+++ new/usr/src/man/man5/smf_method.5.man.txt
1 1 SMF_METHOD(5) Standards, Environments, and Macros SMF_METHOD(5)
2 2
3 3
4 4
5 5 NAME
6 6 smf_method - service management framework conventions for methods
7 7
8 8 DESCRIPTION
9 9 The class of services managed by svc.startd(1M) in the service
10 10 management framework, smf(5), consists of applications that fit a
11 11 simple fork(2)-exec(2) model. The svc.startd(1M) master daemon and
12 12 other restarters support the fork(2)-exec(2) model, potentially with
13 13 additional capabilities. The svc.startd(1M) daemon and other restarters
14 14 require that the methods which activate, manipulate, or examine a
15 15 service instance follow the conventions described in this manual page.
16 16
17 17 Invocation form
18 18 The form of a method invocation is not dictated by convention. In some
19 19 cases, a method invocation might consist of the direct invocation of
20 20 the daemon or other binary executable that provides the service. For
21 21 cases in which an executable script or other mediating executable is
22 22 used, the convention recommends the form:
23 23
24 24 /path/to/method_executable abbr_method_name
25 25
26 26
27 27
28 28 The abbr_method_name used for the recommended form is a supported
29 29 method such as start or stop. The set of methods supported by a
30 30 restarter is given on the related restarter page. The svc.startd(1M)
31 31 daemon supports start, stop, and refresh methods.
32 32
33 33
34 34 A restarter might define other kinds of methods beyond those referenced
35 35 in this page. The conventions surrounding such extensions are defined
36 36 by the restarter and might not be identical to those given here.
37 37
38 38 Environment Variables
39 39 The restarter provides four environment variables to the method that
40 40 determine the context in which the method is invoked.
41 41
42 42 SMF_FMRI
43 43
44 44 The service fault management resource identifier (FMRI) of the
45 45 instance for which the method is invoked.
46 46
47 47
48 48 SMF_METHOD
49 49
50 50 The full name of the method being invoked, such as start or stop.
51 51
52 52
53 53 SMF_RESTARTER
54 54
55 55 The service FMRI of the restarter that invokes the method
56 56
57 57
58 58 SMF_ZONENAME
59 59
60 60 The name of the zone in which the method is running. This can also
61 61 be obtained by using the zonename(1) command.
62 62
63 63
64 64
65 65 These variables should be removed from the environment prior to the
66 66 invocation of any persistent process by the method. A convenience shell
67 67 function, smf_clear_env, is given for service authors who use Bourne-
68 68 compatible shell scripting to compose service methods in the include
69 69 file described below.
70 70
71 71
72 72 The method context can cause other environment variables to be set as
73 73 described below.
74 74
75 75 Method Definition
76 76 A method is defined minimally by three properties in a propertygroup of
77 77 type method.
78 78
79 79
80 80 These properties are:
81 81
82 82 exec (astring)
83 83 Method executable string.
84 84
85 85
86 86 timeout_seconds (count)
87 87 Number of seconds before method times out.
88 88 See the Timeouts section for more detail.
89 89
90 90
91 91 type (astring)
92 92 Method type. Currently always set to method.
93 93
94 94
95 95
96 96 A Method Context can be defined to further refine the execution
97 97 environment of the method. See the Method Context section for more
98 98 information.
99 99
100 100 Method Tokens
101 101 When defined in the exec string of the method by the restarter
102 102 svc.startd, a set of tokens are parsed and expanded with appropriate
103 103 value. Other restarters might not support method tokens. The delegated
104 104 restarter for inet services, inetd(1M), does not support the following
105 105 method expansions.
106 106
107 107 %%
108 108
109 109 %
110 110
111 111
112 112 %r
113 113
114 114 Name of the restarter, such as svc.startd
115 115
116 116
117 117 %m
118 118
119 119 The full name of the method being invoked, such as start or stop.
120 120
121 121
122 122 %s
123 123
124 124 Name of the service
125 125
126 126
127 127 %i
128 128
129 129 Name of the instance
130 130
131 131
132 132 %f
133 133
134 134 FMRI of the instance
135 135
136 136
137 137 %{prop[:,]}
138 138
139 139 Value(s) of a property. The prop might be a property FMRI, a
140 140 property group name and a property name separated by a /, or a
141 141 property name in the application property group. These values can
142 142 be followed by a , (comma) or : (colon). If present, the separators
143 143 are used to separate multiple values. If absent, a space is used.
144 144 The following shell metacharacters encountered in string values are
145 145 quoted with a (backslash):
146 146
147 147 ; & ( ) | ^ < > newline space tab " '
148 148
149 149 An invalid expansion constitutes method failure.
150 150
151 151
152 152
153 153 Two explicit tokens can be used in the place of method commands.
154 154
155 155 :kill [-signal]
156 156
157 157 Sends the specified signal, which is SIGTERM by default, to all
158 158 processes in the primary instance contract. Always returns
159 159 SMF_EXIT_OK. This token should be used to replace common pkill
160 160 invocations.
161 161
162 162
163 163 :true
164 164
165 165 Always returns SMF_EXIT_OK. This token should be used for methods
166 166 that are required by the restarter but which are unnecessary for
167 167 the particular service implementation.
168 168
169 169
170 170 Exiting and Exit Status
171 171 The required behavior of a start method is to delay exiting until the
172 172 service instance is ready to answer requests or is otherwise
173 173 functional.
174 174
175 175
176 176 The following exit status codes are defined in <libscf.h> and in the
177 177 shell support file.
178 178
179 179
180 180
181 181
182 182 SMF_EXIT_OK 0 Method exited, performing its operation successfully.
183 183 SMF_EXIT_ERR_FATAL 95 Method failed fatally and is unrecoverable without administrative intervention.
184 184 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.
185 185 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.
186 186 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.
187 187 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.
188 188
189 189
190 190
191 191 Use of a precise exit code allows the responsible restarter to
192 192 categorize an error response as likely to be intermittent and worth
193 193 pursuing restart or permanent and request administrative intervention.
194 194
195 195 Timeouts
196 196 Each method can have an independent timeout, given in seconds. The
197 197 choice of a particular timeout should be based on site expectations for
198 198 detecting a method failure due to non-responsiveness. Sites with
199 199 replicated filesystems or other failover resources can elect to
200 200 lengthen method timeouts from the default. Sites with no remote
201 201 resources can elect to shorten the timeouts. Method timeout is
202 202 specified by the timeout_seconds property.
203 203
204 204
205 205 If you specify 0 timeout_seconds for a method, it declares to the
206 206 restarter that there is no timeout for the service. This setting is not
207 207 preferred, but is available for services that absolutely require it.
208 208
209 209
210 210 -1 timeout_seconds is also accepted, but is a deprecated specification.
211 211
212 212 Shell Programming Support
213 213 A set of environment variables that define the above exit status values
214 214 is provided with convenience shell functions in the file
215 215 /lib/svc/share/smf_include.sh. This file is a Bourne shell script
216 216 suitable for inclusion via the source operator in any Bourne-compatible
217 217 shell.
218 218
219 219
220 220 To assist in the composition of scripts that can serve as SMF methods
221 221 as well as /etc/init.d scripts, the smf_present() shell function is
222 222 provided. If the smf(5) facility is not available, smf_present()
223 223 returns a non-zero exit status.
224 224
225 225
226 226 One possible structure for such a script follows:
227 227
228 228 if smf_present; then
229 229 # Shell code to run application as managed service
230 230 ....
231 231
232 232 smf_clear_env
233 233 else
234 234 # Shell code to run application as /etc/init.d script
235 235 ....
236 236 fi
237 237
238 238
239 239
240 240 This example shows the use of both convenience functions that are
241 241 provided.
242 242
243 243 Method Context
244 244 The service management facility offers a common mechanism set the
245 245 context in which the fork(2)-exec(2) model services execute.
246 246
247 247
248 248 The desired method context should be provided by the service developer.
249 249 All service instances should run with the lowest level of privileges
250 250 possible to limit potential security compromises.
251 251
252 252
253 253 A method context can contain the following properties:
254 254
255 255 use_profile
256 256
257 257 A boolean that specifies whether the profile should be used instead
258 258 of the user, group, privileges, and limit_privileges properties.
259 259
260 260
261 261 environment
262 262
263 263 Environment variables to insert into the environment of the method,
264 264 in the form of a number of NAME=value strings.
265 265
266 266
267 267 profile
268 268
269 269 The name of an RBAC (role-based access control) profile which,
270 270 along with the method executable, identifies an entry in
271 271 exec_attr(4).
272 272
273 273
274 274 user
275 275
276 276 The user ID in numeric or text form.
277 277
278 278
279 279 group
280 280
281 281 The group ID in numeric or text form.
282 282
283 283
284 284 supp_groups
285 285
286 286 An optional string that specifies the supplemental group
287 287 memberships by ID, in numeric or text form.
288 288
289 289
290 290 privileges
291 291
292 292 An optional string specifying the privilege set as defined in
293 293 privileges(5).
294 294
295 295
296 296 limit_privileges
297 297
298 298 An optional string specifying the limit privilege set as defined in
299 299 privileges(5).
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300 300
301 301
302 302 working_directory
303 303
304 304 The home directory from which to launch the method. :home can be
305 305 used as a token to indicate the home directory of the user whose
306 306 uid is used to launch the method. If the property is unset, :home
307 307 is used.
308 308
309 309
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 +
310 328 corefile_pattern
311 329
312 330 An optional string that specifies the corefile pattern to use for
313 331 the service, as per coreadm(1M). Most restarters supply a default.
314 332 Setting this property overrides local customizations to the global
315 333 core pattern.
316 334
317 335
318 336 project
319 337
320 338 The project ID in numeric or text form. :default can be used as a
321 339 token to indicate a project identified by getdefaultproj(3PROJECT)
322 340 for the user whose uid is used to launch the method.
323 341
324 342
325 343 resource_pool
326 344
327 345 The resource pool name on which to launch the method. :default can
328 346 be used as a token to indicate the pool specified in the project(4)
329 347 entry given in the project attribute above.
330 348
331 349
332 350
333 351 The method context can be set for the entire service instance by
334 352 specifying a method_context property group for the service or instance.
335 353 A method might override the instance method context by providing the
336 354 method context properties on the method property group.
337 355
338 356
339 357 Invalid method context settings always lead to failure of the method,
340 358 with the exception of invalid environment variables that issue
341 359 warnings.
342 360
343 361
344 362 In addition to the context defined above, many fork(2)-exec(2) model
345 363 restarters also use the following conventions when invoking executables
346 364 as methods:
347 365
348 366 Argument array
349 367
350 368 The arguments in argv[] are set consistently with the result
351 369 /bin/sh -c of the exec string.
352 370
353 371
354 372 File descriptors
355 373
356 374 File descriptor 0 is /dev/null. File descriptors 1 and 2 are
357 375 recommended to be a per-service log file.
358 376
359 377
360 378 FILES
361 379 /lib/svc/share/smf_include.sh
362 380
363 381 Definitions of exit status values.
364 382
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365 383
366 384 /usr/include/libscf.h
367 385
368 386 Definitions of exit status codes.
369 387
370 388
371 389 SEE ALSO
372 390 zonename(1), coreadm(1M), inetd(1M), svccfg(1M), svc.startd(1M),
373 391 exec(2), fork(2), getdefaultproj(3PROJECT), exec_attr(4), project(4),
374 392 service_bundle(4), attributes(5), privileges(5), rbac(5), smf(5),
375 - smf_bootstrap(5), zones(5)
393 + smf_bootstrap(5), zones(5), security-flags(5)
376 394
377 395 NOTES
378 396 The present version of smf(5) does not support multiple repositories.
379 397
380 398
381 399 When a service is configured to be started as root but with privileges
382 400 different from limit_privileges, the resulting process is privilege
383 401 aware. This can be surprising to developers who expect seteuid(<non-
384 402 zero UID>) to reduce privileges to basic or less.
385 403
386 404
387 405
388 - May 20, 2009 SMF_METHOD(5)
406 + June 6, 2016 SMF_METHOD(5)
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