1 '\" te
2 .\" Copyright (c) 2007, Sun Microsystems, Inc. All Rights Reserved.
3 .\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License"). You may not use this file except in compliance with the License.
4 .\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing. See the License for the specific language governing permissions and limitations under the License.
5 .\" When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE. If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner]
6 .TH PORT_ASSOCIATE 3C "Nov 9, 2007"
7 .SH NAME
8 port_associate, port_dissociate \- associate or dissociate the object with the
9 port
10 .SH SYNOPSIS
11 .LP
12 .nf
13 #include <port.h>
14
15 \fBint\fR \fBport_associate\fR(\fBint\fR \fIport\fR, \fBint\fR \fIsource\fR, \fBuintptr_t\fR \fIobject\fR,
16 \fBint\fR \fIevents\fR, \fBvoid *\fR\fIuser\fR);
17 .fi
18
19 .LP
20 .nf
21 \fBint\fR \fBport_dissociate\fR(\fBint\fR \fIport\fR, \fBint\fR \fIsource\fR, \fBuintptr_t\fR \fIobject\fR);
22 .fi
23
24 .SH DESCRIPTION
25 .sp
26 .LP
27 The \fBport_associate()\fR function associates specific \fIevents\fR of a given
28 \fIobject\fR with a \fIport\fR. Only objects associated with a particular port
29 are able to generate events that can be retrieved using \fBport_get\fR(3C) or
30 \fBport_getn\fR(3C). The delivery event has its \fBportev_user\fR member set to
31 the value specified in the \fIuser\fR parameter. If the specified object is
32 already associated with the specified port, the \fBport_associate()\fR function
33 serves to update the \fIevents\fR and \fIuser\fR arguments of the association.
34 The \fBport_dissociate()\fR function removes the association of an object with
35 a port.
36 .sp
37 .LP
38 The objects that can be associated with a port by way of the
39 \fBport_associate()\fR function are objects of type \fBPORT_SOURCE_FD\fR and
40 \fBPORT_SOURCE_FILE\fR. Objects of other types have type-specific association
41 mechanisms. A \fBport_notify_t\fR structure, defined in \fB<port.h>\fR, is used
42 to specify the event port and an application-defined cookie to associate with
43 these event sources. See \fBport_create\fR(3C) and \fBsignal.h\fR(3HEAD).
44 .sp
45 .LP
46 The \fBport_notify_t\fR structure contains the following members:
47 .sp
48 .in +2
49 .nf
50 int portntfy_port; /* bind request(s) to port */
51 void *portntfy_user; /* user defined cookie */
52 .fi
53 .in -2
54
55 .sp
56 .LP
57 Objects of type \fBPORT_SOURCE_FD\fR are file descriptors. The event types for
58 \fBPORT_SOURCE_FD\fR objects are described in \fBpoll\fR(2). At most one event
59 notification will be generated per associated file descriptor. For example, if
60 a file descriptor is associated with a port for the \fBPOLLRDNORM\fR event and
61 data is available on the file descriptor at the time the \fBport_associate()\fR
62 function is called, an event is immediately sent to the port. If data is not
63 yet available, one event is sent to the port when data first becomes available.
64 .sp
65 .LP
66 When an event for a \fBPORT_SOURCE_FD\fR object is retrieved, the object no
67 longer has an association with the port. The event can be processed without
68 the possibility that another thread can retrieve a subsequent event for the
69 same object. After processing of the file descriptor is completed, the
70 \fBport_associate()\fR function can be called to reassociate the object with
71 the port.
72 .sp
73 .LP
74 Objects of type \fBPORT_SOURCE_FILE\fR are pointer to the structure
75 \fBfile_obj\fR defined in \fB<sys/port.h>\fR. This event source provides event
76 notification when the specified file/directory is accessed, modified,
77 truncated or when its status changes. The path name of the file/directory to
78 be watched is passed in the \fBstruct file_obj\fR along with the \fBaccess\fR,
79 \fBmodification\fR, and \fBchange\fR time stamps acquired from a \fBstat\fR(2)
80 call. If the file name is a symbolic link, it is followed by default. The
81 \fBFILE_NOFOLLOW\fR needs to be passed in along with the specified events if
82 the symbolic link itself needs to be watched and \fBlstat()\fR needs to be
83 used to get the file status of the symbolic link file.
84 .sp
85 .LP
86 The \fBstruct file_obj\fR contains the following elements:
87 .sp
88 .in +2
89 .nf
90 timestruc_t fo_atime; /* Access time from stat() */
91 timestruc_t fo_mtime; /* Modification time from stat() */
92 timestruc_t fo_ctime; /* Change time from stat() */
93 char *fo_name; /* Pointer to a null terminated path name */
94 .fi
95 .in -2
96
97 .sp
98 .LP
99 At the time the \fBport_associate()\fR function is called, the time stamps
100 passed in the structure \fBfile_obj\fR are compared with the file or
101 directory's current time stamps and, if there has been a change, an event is
102 immediately sent to the port. If not, an event will be sent when such a change
103 occurs.
104 .sp
105 .LP
106 The event types that can be specified at \fBport_associate()\fR time for
107 \fBPORT_SOURCE_FILE\fR are \fBFILE_ACCESS\fR, \fBFILE_MODIFIED\fR,
108 \fBFILE_ATTRIB\fR, and \fbFILE_TRUNC\fR. The first three of these correspond
109 to the three time stamps: an \fBfo_atime\fR change results in the
110 \fBFILE_ACCESS\fR event, an \fBfo_mtime\fR change results in the
111 \fBFILE_MODIFIED\fR event, and an \fBfo_ctime\fR change results in the
112 \fBFILE_ATTRIB\fR event. If the operation that induced the time stamp update
113 also truncated the file, \fBFILE_TRUNC\fR will be set in the resulting event.
114 .sp
115 .LP
116 The following exception events are delivered when they occur. These event types
117 cannot be filtered.
118 .sp
119 .in +2
120 .nf
121 FILE_DELETE /* Monitored file/directory was deleted */
122 FILE_RENAME_TO /* Monitored file/directory was renamed */
123 FILE_RENAME_FROM /* Monitored file/directory was renamed */
124 UNMOUNTED /* Monitored file system got unmounted */
125 MOUNTEDOVER /* Monitored file/directory was mounted over */
126 .fi
127 .in -2
128
129 .sp
130 .LP
131 At most one event notification will be generated per associated \fBfile_obj\fR.
132 When the event for the associated \fBfile_obj\fR is retrieved, the object is no
133 longer associated with the port. The event can be processed without the
134 possibility that another thread can retrieve a subsequent event for the same
135 object. The \fBport_associate()\fR can be called to reassociate the
136 \fBfile_obj\fR object with the port.
137 .sp
138 .LP
139 The association is also removed if the port gets closed or when
140 \fBport_dissociate()\fR is called.
141 .sp
142 .LP
143 The parent and child processes are allowed to retrieve events from file
144 descriptors shared after a call to \fBfork\fR(2). The process performing the
145 first association with a port (parent or child process) is designated as the
146 owner of the association. Only the owner of an association is allowed to
147 dissociate the file descriptor from a port. The association is removed if the
148 owner of the association closes the port .
149 .sp
150 .LP
151 On NFS file systems, events from only the client side (local)
152 access/modifications to files or directories will be delivered.
153 .SH RETURN VALUES
154 .sp
155 .LP
156 Upon succesful completion, 0 is returned. Otherwise, \(mi1 is returned and
157 \fBerrno\fR is set to indicate the error.
158 .SH ERRORS
159 .sp
160 .LP
161 The \fBport_associate()\fR and \fBport_dissociate()\fR functions will fail if:
162 .sp
163 .ne 2
164 .na
165 \fB\fBEBADF\fR\fR
166 .ad
167 .RS 10n
168 The \fIport\fR identifier is not valid.
169 .RE
170
171 .sp
172 .ne 2
173 .na
174 \fB\fBEBADFD\fR\fR
175 .ad
176 .RS 10n
177 The \fIsource\fR argument is of type \fBPORT_SOURCE_FD\fR and the object
178 argument is not a valid file descriptor.
179 .RE
180
181 .sp
182 .ne 2
183 .na
184 \fB\fBEINVAL\fR\fR
185 .ad
186 .RS 10n
187 The \fIsource\fR argument is not valid.
188 .RE
189
190 .sp
191 .LP
192 The \fBport_associate()\fR function will fail if:
193 .sp
194 .ne 2
195 .na
196 \fB\fBEACCES\fR\fR
197 .ad
198 .RS 11n
199 The source argument is \fBPORT_SOURCE_FILE\fR and, Search permission is denied
200 on a component of path prefix or the file exists and the permissions,
201 corresponding to the events argument, are denied.
202 .RE
203
204 .sp
205 .ne 2
206 .na
207 \fB\fBEAGAIN\fR\fR
208 .ad
209 .RS 11n
210 The maximum number of objects associated with the port was exceeded. The
211 maximum allowable number of events or association of objects per port is the
212 minimum value of the \fBprocess.max-port-events\fR resource control at the time
213 \fBport_create\fR(3C) was used to create the port. See \fBsetrctl\fR(2) and
214 \fBrctladm\fR(1M) for information on using resource controls.
215 .sp
216 The number of objects associated with a port is composed of all supported
217 resource types. Some of the source types do not explicitly use the
218 \fBport_associate()\fR function.
219 .RE
220
221 .sp
222 .ne 2
223 .na
224 \fB\fBENOENT\fR\fR
225 .ad
226 .RS 11n
227 The source argument is \fBPORT_SOURCE_FILE\fR and the file does not exist or
228 the path prefix does not exist or the path points to an empty string.
229 .RE
230
231 .sp
232 .ne 2
233 .na
234 \fB\fBENOMEM\fR\fR
235 .ad
236 .RS 11n
237 The physical memory limits of the system have been exceeded.
238 .RE
239
240 .sp
241 .ne 2
242 .na
243 \fB\fBENOTSUP\fR\fR
244 .ad
245 .RS 11n
246 The source argument is \fBPORT_SOURCE_FILE\fR and the file system on which the
247 specified file resides, does not support watching for file events
248 notifications.
249 .RE
250
251 .sp
252 .LP
253 The \fBport_dissociate()\fR function will fail if:
254 .sp
255 .ne 2
256 .na
257 \fB\fBEACCES\fR\fR
258 .ad
259 .RS 10n
260 The process is not the owner of the association.
261 .RE
262
263 .sp
264 .ne 2
265 .na
266 \fB\fBENOENT\fR\fR
267 .ad
268 .RS 10n
269 The specified object is not associated with the port.
270 .RE
271
272 .SH EXAMPLES
273 .LP
274 \fBExample 1 \fRRetrieve data from a pipe file descriptor.
275 .sp
276 .LP
277 The following example retrieves data from a pipe file descriptor.
278
279 .sp
280 .in +2
281 .nf
282 #include <port.h>
283
284 int port;
285 int fd;
286 int error;
287 int index;
288 void *mypointer;
289 port_event_t pev;
290 struct timespec_t timeout;
291 char rbuf[STRSIZE];
292 int fds[MAXINDEX];
293
294 /* create a port */
295 port = port_create();
296
297 for (index = 0; index < MAXINDEX; index++) {
298 error = mkfifo(name[index], S_IRWXU | S_IRWXG | S_IRWXO);
299 if (error)
300 /* handle error code */
301 fds[index] = open(name[index], O_RDWR);
302
303 /* associate pipe file descriptor with the port */
304 error = port_associate(port, PORT_SOURCE_FD, fds[index],
305 POLLIN, mypointer);
306 }
307 \&...
308 timeout.tv_sec = 1; /* user defined */
309 timeout.tv_nsec = 0;
310
311 /* loop to retrieve data from the list of pipe file descriptors */
312 for (...) {
313 /* retrieve a single event */
314 error = port_get(port, &pev, &timeout);
315 if (error) {
316 /* handle error code */
317 }
318 fd = pev.portev_object;
319 if (read(fd, rbuf, STRSIZE)) {
320 /* handle error code */
321 }
322 if (fd-still-accepting-data) {
323 /*
324 * re-associate the file descriptor with the port.
325 * The re-association is required for the
326 * re-activation of the data detection.
327 * Internals events and user arguments are set to the
328 * new (or the same) values delivered here.
329 */
330 error = port_associate(port, PORT_SOURCE_FD, fd, POLLIN,
331 pev.portev_user);
332 } else {
333 /*
334 * If file descriptor is no longer required,
335 * - it can remain disabled but still associated with
336 * the port, or
337 * - it can be dissociated from the port.
338 */
339 }
340 .fi
341 .in -2
342
343 .LP
344 \fBExample 2 \fRBind AIO transaction to a specific port.
345 .sp
346 .LP
347 The following example binds the AIO transaction to a specific port.
348
349 .sp
350 .in +2
351 .nf
352 #include <port.h>
353
354 int port;
355 port_notify_t pn;
356 aiocb_t aiocb;
357 aiocb_t *aiocbp;
358 void *mypointer;
359 int error;
360 int my_errno;
361 int my_status;
362 struct timespec_t timeout;
363 port_event_t pev;
364
365 port = port_create();
366 \&...
367 /* fill AIO specific part */
368 aiocb.aio_fildes = fd;
369 aiocb.aio_nbytes = BUFSIZE;
370 aiocb.aio_buf = bufp;
371 aiocb.aio_offset = 0;
372
373 /* port specific part */
374 pn.portnfy_port = port;
375 pn.portnfy_user = mypointer;
376 aiocb.aio_sigevent.sigev_notify = SIGEV_PORT;
377 aiocb.aio_sigevent.sigev_value.sival_ptr = &pn
378
379 /*
380 * The aio_read() function binds internally the asynchronous I/O
381 * transaction with the port delivered in port_notify_t.
382 */
383 error = aio_read(&aiocb);
384
385 timeout.tv_sec = 1; /* user defined */
386 timeout.tv_nsec = 0;
387
388 /* retrieve a single event */
389 error = port_get(port, &pev, &timeout);
390 if (error) {
391 /* handle error code */
392 }
393
394 /*
395 * pev.portev_object contains a pointer to the aiocb structure
396 * delivered in port_notify_t (see aio_read()).
397 */
398 aiocbp = pev.portev_object;
399
400 /* check error code and return value in
401 my_errno = aio_error(aiocbp);
402 \&...
403 my_status = aio_return(aiocbp);
404 \&...
405 .fi
406 .in -2
407
408 .SH ATTRIBUTES
409 .sp
410 .LP
411 See \fBattributes\fR(5) for descriptions of the following attributes:
412 .sp
413
414 .sp
415 .TS
416 box;
417 c | c
418 l | l .
419 ATTRIBUTE TYPE ATTRIBUTE VALUE
420 _
421 Architecture all
422 _
423 Interface Stability Committed
424 _
425 MT-Level Safe
426 .TE
427
428 .SH SEE ALSO
429 .sp
430 .LP
431 \fBrctladm\fR(1M), \fBpoll\fR(2), \fBsetrctl\fR(2), \fBport_alert\fR(3C),
432 \fBport_create\fR(3C), \fBport_get\fR(3C), \fBport_send\fR(3C),
433 \fBsignal.h\fR(3HEAD), \fBattributes\fR(5)