1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /*
28 * Copyright 2020 Joyent, Inc.
29 */
30
31 #include <sys/types.h>
32 #include <sys/systm.h>
33 #include <sys/cred.h>
34 #include <sys/modctl.h>
35 #include <sys/vfs.h>
36 #include <sys/vfs_opreg.h>
37 #include <sys/sysmacros.h>
38 #include <sys/cmn_err.h>
39 #include <sys/stat.h>
40 #include <sys/errno.h>
41 #include <sys/kmem.h>
42 #include <sys/file.h>
43 #include <sys/kstat.h>
44 #include <sys/port_impl.h>
45 #include <sys/task.h>
46 #include <sys/project.h>
47
48 /*
49 * Event Ports can be shared across threads or across processes.
50 * Every thread/process can use an own event port or a group of them
51 * can use a single port. A major request was also to get the ability
52 * to submit user-defined events to a port. The idea of the
53 * user-defined events is to use the event ports for communication between
54 * threads/processes (like message queues). User defined-events are queued
55 * in a port with the same priority as other event types.
56 *
57 * Events are delivered only once. The thread/process which is waiting
58 * for events with the "highest priority" (priority here is related to the
59 * internal strategy to wakeup waiting threads) will retrieve the event,
60 * all other threads/processes will not be notified. There is also
61 * the requirement to have events which should be submitted immediately
62 * to all "waiting" threads. That is the main task of the alert event.
63 * The alert event is submitted by the application to a port. The port
64 * changes from a standard mode to the alert mode. Now all waiting threads
65 * will be awaken immediately and they will return with the alert event.
66 * Threads trying to retrieve events from a port in alert mode will
67 * return immediately with the alert event.
68 *
69 *
70 * An event port is like a kernel queue, which accept events submitted from
71 * user level as well as events submitted from kernel sub-systems. Sub-systems
72 * able to submit events to a port are the so-called "event sources".
73 * Current event sources:
74 * PORT_SOURCE_AIO : events submitted per transaction completion from
75 * POSIX-I/O framework.
76 * PORT_SOURCE_TIMER : events submitted when a timer fires
77 * (see timer_create(3RT)).
78 * PORT_SOURCE_FD : events submitted per file descriptor (see poll(2)).
79 * PORT_SOURCE_ALERT : events submitted from user. This is not really a
80 * single event, this is actually a port mode
81 * (see port_alert(3c)).
82 * PORT_SOURCE_USER : events submitted by applications with
83 * port_send(3c) or port_sendn(3c).
84 * PORT_SOURCE_FILE : events submitted per file being watched for file
85 * change events (see port_create(3c).
86 *
87 * There is a user API implemented in the libc library as well as a
88 * kernel API implemented in port_subr.c in genunix.
89 * The available user API functions are:
90 * port_create() : create a port as a file descriptor of portfs file system
91 * The standard close(2) function closes a port.
92 * port_associate() : associate a file descriptor with a port to be able to
93 * retrieve events from that file descriptor.
94 * port_dissociate(): remove the association of a file descriptor with a port.
95 * port_alert() : set/unset a port in alert mode
96 * port_send() : send an event of type PORT_SOURCE_USER to a port
97 * port_sendn() : send an event of type PORT_SOURCE_USER to a list of ports
98 * port_get() : retrieve a single event from a port
99 * port_getn() : retrieve a list of events from a port
100 *
101 * The available kernel API functions are:
102 * port_allocate_event(): allocate an event slot/structure of/from a port
103 * port_init_event() : set event data in the event structure
104 * port_send_event() : send event to a port
105 * port_free_event() : deliver allocated slot/structure back to a port
106 * port_associate_ksource(): associate a kernel event source with a port
107 * port_dissociate_ksource(): dissociate a kernel event source from a port
108 *
109 * The libc implementation consists of small functions which pass the
110 * arguments to the kernel using the "portfs" system call. It means, all the
111 * synchronisation work is being done in the kernel. The "portfs" system
112 * call loads the portfs file system into the kernel.
113 *
114 * PORT CREATION
115 * The first function to be used is port_create() which internally creates
116 * a vnode and a portfs node. The portfs node is represented by the port_t
117 * structure, which again includes all the data necessary to control a port.
118 * port_create() returns a file descriptor, which needs to be used in almost
119 * all other event port functions.
120 * The maximum number of ports per system is controlled by the resource
121 * control: project:port-max-ids.
122 *
123 * EVENT GENERATION
124 * The second step is the triggering of events, which could be sent to a port.
125 * Every event source implements an own method to generate events for a port:
126 * PORT_SOURCE_AIO:
127 * The sigevent structure of the standard POSIX-IO functions
128 * was extended by an additional notification type.
129 * Standard notification types:
130 * SIGEV_NONE, SIGEV_SIGNAL and SIGEV_THREAD
131 * Event ports introduced now SIGEV_PORT.
132 * The notification type SIGEV_PORT specifies that a structure
133 * of type port_notify_t has to be attached to the sigev_value.
134 * The port_notify_t structure contains the event port file
135 * descriptor and a user-defined pointer.
136 * Internally the AIO implementation will use the kernel API
137 * functions to allocate an event port slot per transaction (aiocb)
138 * and sent the event to the port as soon as the transaction completes.
139 * All the events submitted per transaction are of type
140 * PORT_SOURCE_AIO.
141 * PORT_SOURCE_TIMER:
142 * The timer_create() function uses the same method as the
143 * PORT_SOURCE_AIO event source. It also uses the sigevent structure
144 * to deliver the port information.
145 * Internally the timer code will allocate a single event slot/struct
146 * per timer and it will send the timer event as soon as the timer
147 * fires. If the timer-fired event is not delivered to the application
148 * before the next period elapsed, then an overrun counter will be
149 * incremented. The timer event source uses a callback function to
150 * detect the delivery of the event to the application. At that time
151 * the timer callback function will update the event overrun counter.
152 * PORT_SOURCE_FD:
153 * This event source uses the port_associate() function to allocate
154 * an event slot/struct from a port. The application defines in the
155 * events argument of port_associate() the type of events which it is
156 * interested on.
157 * The internal pollwakeup() function is used by all the file
158 * systems --which are supporting the VOP_POLL() interface- to notify
159 * the upper layer (poll(2), devpoll(7d) and now event ports) about
160 * the event triggered (see valid events in poll(2)).
161 * The pollwakeup() function forwards the event to the layer registered
162 * to receive the current event.
163 * The port_dissociate() function can be used to free the allocated
164 * event slot from the port. Anyway, file descriptors deliver events
165 * only one time and remain deactivated until the application
166 * reactivates the association of a file descriptor with port_associate().
167 * If an associated file descriptor is closed then the file descriptor
168 * will be dissociated automatically from the port.
169 *
170 * PORT_SOURCE_ALERT:
171 * This event type is generated when the port was previously set in
172 * alert mode using the port_alert() function.
173 * A single alert event is delivered to every thread which tries to
174 * retrieve events from a port.
175 * PORT_SOURCE_USER:
176 * This type of event is generated from user level using the port_send()
177 * function to send a user event to a port or the port_sendn() function
178 * to send an event to a list of ports.
179 * PORT_SOURCE_FILE:
180 * This event source uses the port_associate() interface to register
181 * a file to be monitored for changes. The file name that needs to be
182 * monitored is specified in the file_obj_t structure, a pointer to which
183 * is passed as an argument. The event types to be monitored are specified
184 * in the events argument.
185 * A file events monitor is represented internal per port per object
186 * address(the file_obj_t pointer). Which means there can be multiple
187 * watches registered on the same file using different file_obj_t
188 * structure pointer. With the help of the FEM(File Event Monitoring)
189 * hooks, the file's vnode ops are intercepted and relevant events
190 * delivered. The port_dissociate() function is used to de-register a
191 * file events monitor on a file. When the specified file is
192 * removed/renamed, the file events watch/monitor is automatically
193 * removed.
194 *
195 * EVENT DELIVERY / RETRIEVING EVENTS
196 * Events remain in the port queue until:
197 * - the application uses port_get() or port_getn() to retrieve events,
198 * - the event source cancel the event,
199 * - the event port is closed or
200 * - the process exits.
201 * The maximal number of events in a port queue is the maximal number
202 * of event slots/structures which can be allocated by event sources.
203 * The allocation of event slots/structures is controlled by the resource
204 * control: process.port-max-events.
205 * The port_get() function retrieves a single event and the port_getn()
206 * function retrieves a list of events.
207 * Events are classified as shareable and non-shareable events across processes.
208 * Non-shareable events are invisible for the port_get(n)() functions of
209 * processes other than the owner of the event.
210 * Shareable event types are:
211 * PORT_SOURCE_USER events
212 * This type of event is unconditionally shareable and without
213 * limitations. If the parent process sends a user event and closes
214 * the port afterwards, the event remains in the port and the child
215 * process will still be able to retrieve the user event.
216 * PORT_SOURCE_ALERT events
217 * This type of event is shareable between processes.
218 * Limitation: The alert mode of the port is removed if the owner
219 * (process which set the port in alert mode) of the
220 * alert event closes the port.
221 * PORT_SOURCE_FD events
222 * This type of event is conditional shareable between processes.
223 * After fork(2) all forked file descriptors are shareable between
224 * the processes. The child process is allowed to retrieve events
225 * from the associated file descriptors and it can also re-associate
226 * the fd with the port.
227 * Limitations: The child process is not allowed to dissociate
228 * the file descriptor from the port. Only the
229 * owner (process) of the association is allowed to
230 * dissociate the file descriptor from the port.
231 * If the owner of the association closes the port
232 * the association will be removed.
233 * PORT_SOURCE_AIO events
234 * This type of event is not shareable between processes.
235 * PORT_SOURCE_TIMER events
236 * This type of event is not shareable between processes.
237 * PORT_SOURCE_FILE events
238 * This type of event is not shareable between processes.
239 *
240 * FORK BEHAVIOUR
241 * On fork(2) the child process inherits all opened file descriptors from
242 * the parent process. This is also valid for port file descriptors.
243 * Associated file descriptors with a port maintain the association across the
244 * fork(2). It means, the child process gets full access to the port and
245 * it can retrieve events from all common associated file descriptors.
246 * Events of file descriptors created and associated with a port after the
247 * fork(2) are non-shareable and can only be retrieved by the same process.
248 *
249 * If the parent or the child process closes an exported port (using fork(2)
250 * or I_SENDFD) all the file descriptors associated with the port by the
251 * process will be dissociated from the port. Events of dissociated file
252 * descriptors as well as all non-shareable events will be discarded.
253 * The other process can continue working with the port as usual.
254 *
255 * CLOSING A PORT
256 * close(2) has to be used to close a port. See FORK BEHAVIOUR for details.
257 *
258 * PORT EVENT STRUCTURES
259 * The global control structure of the event ports framework is port_control_t.
260 * port_control_t keeps track of the number of created ports in the system.
261 * The cache of the port event structures is also located in port_control_t.
262 *
263 * On port_create() the vnode and the portfs node is also created.
264 * The portfs node is represented by the port_t structure.
265 * The port_t structure manages all port specific tasks:
266 * - management of resource control values
267 * - port VOP_POLL interface
268 * - creation time
269 * - uid and gid of the port
270 *
271 * The port_t structure contains the port_queue_t structure.
272 * The port_queue_t structure contains all the data necessary for the
273 * queue management:
274 * - locking
275 * - condition variables
276 * - event counters
277 * - submitted events (represented by port_kevent_t structures)
278 * - threads waiting for event delivery (check portget_t structure)
279 * - PORT_SOURCE_FD cache (managed by the port_fdcache_t structure)
280 * - event source management (managed by the port_source_t structure)
281 * - alert mode management (check port_alert_t structure)
282 *
283 * EVENT MANAGEMENT
284 * The event port file system creates a kmem_cache for internal allocation of
285 * event port structures.
286 *
287 * 1. Event source association with a port:
288 * The first step to do for event sources is to get associated with a port
289 * using the port_associate_ksource() function or adding an entry to the
290 * port_ksource_tab[]. An event source can get dissociated from a port
291 * using the port_dissociate_ksource() function. An entry in the
292 * port_ksource_tab[] implies that the source will be associated
293 * automatically with every new created port.
294 * The event source can deliver a callback function, which is used by the
295 * port to notify the event source about close(2). The idea is that
296 * in such a case the event source should free all allocated resources
297 * and it must return to the port all allocated slots/structures.
298 * The port_close() function will wait until all allocated event
299 * structures/slots are returned to the port.
300 * The callback function is not necessary when the event source does not
301 * maintain local resources, a second condition is that the event source
302 * can guarantee that allocated event slots will be returned without
303 * delay to the port (it will not block and sleep somewhere).
304 *
305 * 2. Reservation of an event slot / event structure
306 * The event port reliability is based on the reservation of an event "slot"
307 * (allocation of an event structure) by the event source as part of the
308 * application call. If the maximal number of event slots is exhausted then
309 * the event source can return a corresponding error code to the application.
310 *
311 * The port_alloc_event() function has to be used by event sources to
312 * allocate an event slot (reserve an event structure). The port_alloc_event()
313 * doesn not block and it will return a 0 value on success or an error code
314 * if it fails.
315 * An argument of port_alloc_event() is a flag which determines the behavior
316 * of the event after it was delivered to the application:
317 * PORT_ALLOC_DEFAULT : event slot becomes free after delivery to the
318 * application.
319 * PORT_ALLOC_PRIVATE : event slot remains under the control of the event
320 * source. This kind of slots can not be used for
321 * event delivery and should only be used internally
322 * by the event source.
323 * PORT_KEV_CACHED : event slot remains under the control of an event
324 * port cache. It does not become free after delivery
325 * to the application.
326 * PORT_ALLOC_SCACHED : event slot remains under the control of the event
327 * source. The event source takes the control over
328 * the slot after the event is delivered to the
329 * application.
330 *
331 * 3. Delivery of events to the event port
332 * Earlier allocated event structure/slot has to be used to deliver
333 * event data to the port. Event source has to use the function
334 * port_send_event(). The single argument is a pointer to the previously
335 * reserved event structure/slot.
336 * The portkev_events field of the port_kevent_t structure can be updated/set
337 * in two ways:
338 * 1. using the port_set_event() function, or
339 * 2. updating the portkev_events field out of the callback function:
340 * The event source can deliver a callback function to the port as an
341 * argument of port_init_event().
342 * One of the arguments of the callback function is a pointer to the
343 * events field, which will be delivered to the application.
344 * (see Delivery of events to the application).
345 * Event structures/slots can be delivered to the event port only one time,
346 * they remain blocked until the data is delivered to the application and the
347 * slot becomes free or it is delivered back to the event source
348 * (PORT_ALLOC_SCACHED). The activation of the callback function mentioned above
349 * is at the same time the indicator for the event source that the event
350 * structure/slot is free for reuse.
351 *
352 * 4. Delivery of events to the application
353 * The events structures/slots delivered by event sources remain in the
354 * port queue until they are retrieved by the application or the port
355 * is closed (exit(2) also closes all opened file descriptors)..
356 * The application uses port_get() or port_getn() to retrieve events from
357 * a port. port_get() retrieves a single event structure/slot and port_getn()
358 * retrieves a list of event structures/slots.
359 * Both functions are able to poll for events and return immediately or they
360 * can specify a timeout value.
361 * Before the events are delivered to the application they are moved to a
362 * second temporary internal queue. The idea is to avoid lock collisions or
363 * contentions of the global queue lock.
364 * The global queue lock is used every time when an event source delivers
365 * new events to the port.
366 * The port_get() and port_getn() functions
367 * a) retrieve single events from the temporary queue,
368 * b) prepare the data to be passed to the application memory,
369 * c) activate the callback function of the event sources:
370 * - to get the latest event data,
371 * - the event source can free all allocated resources associated with the
372 * current event,
373 * - the event source can re-use the current event slot/structure
374 * - the event source can deny the delivery of the event to the application
375 * (e.g. because of the wrong process).
376 * d) put the event back to the temporary queue if the event delivery was denied
377 * e) repeat a) until d) as long as there are events in the queue and
378 * there is enough user space available.
379 *
380 * The loop described above could block for a very long time the global mutex,
381 * to avoid that a second mutex was introduced to synchronized concurrent
382 * threads accessing the temporary queue.
383 */
384
385 static int64_t portfs(int, uintptr_t, uintptr_t, uintptr_t, uintptr_t,
386 uintptr_t);
387
388 static struct sysent port_sysent = {
389 6,
390 SE_ARGC | SE_64RVAL | SE_NOUNLOAD,
391 (int (*)())(uintptr_t)portfs,
392 };
393
394 static struct modlsys modlsys = {
395 &mod_syscallops, "event ports", &port_sysent
396 };
397
398 #ifdef _SYSCALL32_IMPL
399
400 static int64_t
401 portfs32(uint32_t arg1, int32_t arg2, uint32_t arg3, uint32_t arg4,
402 uint32_t arg5, uint32_t arg6);
403
404 static struct sysent port_sysent32 = {
405 6,
406 SE_ARGC | SE_64RVAL | SE_NOUNLOAD,
407 (int (*)())(uintptr_t)portfs32,
408 };
409
410 static struct modlsys modlsys32 = {
411 &mod_syscallops32,
412 "32-bit event ports syscalls",
413 &port_sysent32
414 };
415 #endif /* _SYSCALL32_IMPL */
416
417 static struct modlinkage modlinkage = {
418 MODREV_1,
419 &modlsys,
420 #ifdef _SYSCALL32_IMPL
421 &modlsys32,
422 #endif
423 NULL
424 };
425
426 port_kstat_t port_kstat = {
427 { "ports", KSTAT_DATA_UINT32 }
428 };
429
430 dev_t portdev;
431 struct vnodeops *port_vnodeops;
432 struct vfs port_vfs;
433
434 extern rctl_hndl_t rc_process_portev;
435 extern rctl_hndl_t rc_project_portids;
436 extern void aio_close_port(void *, int, pid_t, int);
437
438 /*
439 * This table contains a list of event sources which need a static
440 * association with a port (every port).
441 * The last NULL entry in the table is required to detect "end of table".
442 */
443 struct port_ksource port_ksource_tab[] = {
444 {PORT_SOURCE_AIO, aio_close_port, NULL, NULL},
445 {0, NULL, NULL, NULL}
446 };
447
448 /* local functions */
449 static int port_getn(port_t *, port_event_t *, uint_t, uint_t *,
450 port_gettimer_t *);
451 static int port_sendn(int [], int [], uint_t, int, void *, uint_t *);
452 static int port_alert(port_t *, int, int, void *);
453 static int port_dispatch_event(port_t *, int, int, int, uintptr_t, void *);
454 static int port_send(port_t *, int, int, void *);
455 static int port_create(int *);
456 static int port_get_alert(port_alert_t *, port_event_t *);
457 static int port_copy_event(port_event_t *, port_kevent_t *, list_t *);
458 static int *port_errorn(int *, int, int, int);
459 static int port_noshare(void *, int *, pid_t, int, void *);
460 static int port_get_timeout(timespec_t *, timespec_t *, timespec_t **, int *,
461 int);
462 static void port_init(port_t *);
463 static void port_remove_alert(port_queue_t *);
464 static void port_add_ksource_local(port_t *, port_ksource_t *);
465 static void port_check_return_cond(port_queue_t *);
466 static void port_dequeue_thread(port_queue_t *, portget_t *);
467 static portget_t *port_queue_thread(port_queue_t *, uint_t);
468 static void port_kstat_init(void);
469
470 #ifdef _SYSCALL32_IMPL
471 static int port_copy_event32(port_event32_t *, port_kevent_t *, list_t *);
472 #endif
473
474 int
475 _init(void)
476 {
477 static const fs_operation_def_t port_vfsops_template[] = {
478 NULL, NULL
479 };
480 extern const fs_operation_def_t port_vnodeops_template[];
481 vfsops_t *port_vfsops;
482 int error;
483 major_t major;
484
485 if ((major = getudev()) == (major_t)-1)
486 return (ENXIO);
487 portdev = makedevice(major, 0);
488
489 /* Create a dummy vfs */
490 error = vfs_makefsops(port_vfsops_template, &port_vfsops);
491 if (error) {
492 cmn_err(CE_WARN, "port init: bad vfs ops");
493 return (error);
494 }
495 vfs_setops(&port_vfs, port_vfsops);
496 port_vfs.vfs_flag = VFS_RDONLY;
497 port_vfs.vfs_dev = portdev;
498 vfs_make_fsid(&(port_vfs.vfs_fsid), portdev, 0);
499
500 error = vn_make_ops("portfs", port_vnodeops_template, &port_vnodeops);
501 if (error) {
502 vfs_freevfsops(port_vfsops);
503 cmn_err(CE_WARN, "port init: bad vnode ops");
504 return (error);
505 }
506
507 mutex_init(&port_control.pc_mutex, NULL, MUTEX_DEFAULT, NULL);
508 port_control.pc_nents = 0; /* number of active ports */
509
510 /* create kmem_cache for port event structures */
511 port_control.pc_cache = kmem_cache_create("port_cache",
512 sizeof (port_kevent_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
513
514 port_kstat_init(); /* init port kstats */
515 return (mod_install(&modlinkage));
516 }
517
518 int
519 _info(struct modinfo *modinfop)
520 {
521 return (mod_info(&modlinkage, modinfop));
522 }
523
524 /*
525 * System call wrapper for all port related system calls from 32-bit programs.
526 */
527 #ifdef _SYSCALL32_IMPL
528 static int64_t
529 portfs32(uint32_t opcode, int32_t a0, uint32_t a1, uint32_t a2, uint32_t a3,
530 uint32_t a4)
531 {
532 int64_t error;
533
534 switch (opcode & PORT_CODE_MASK) {
535 case PORT_GET:
536 error = portfs(PORT_GET, a0, a1, (int)a2, (int)a3, a4);
537 break;
538 case PORT_SENDN:
539 error = portfs(opcode, (uint32_t)a0, a1, a2, a3, a4);
540 break;
541 default:
542 error = portfs(opcode, a0, a1, a2, a3, a4);
543 break;
544 }
545 return (error);
546 }
547 #endif /* _SYSCALL32_IMPL */
548
549 /*
550 * System entry point for port functions.
551 * a0 is a port file descriptor (except for PORT_SENDN and PORT_CREATE).
552 * The libc uses PORT_SYS_NOPORT in functions which do not deliver a
553 * port file descriptor as first argument.
554 */
555 static int64_t
556 portfs(int opcode, uintptr_t a0, uintptr_t a1, uintptr_t a2, uintptr_t a3,
557 uintptr_t a4)
558 {
559 rval_t r;
560 port_t *pp;
561 int error = 0;
562 uint_t nget;
563 file_t *fp;
564 port_gettimer_t port_timer;
565
566 r.r_vals = 0;
567 if (opcode & PORT_SYS_NOPORT) {
568 opcode &= PORT_CODE_MASK;
569 if (opcode == PORT_SENDN) {
570 error = port_sendn((int *)a0, (int *)a1, (uint_t)a2,
571 (int)a3, (void *)a4, (uint_t *)&r.r_val1);
572 if (error && (error != EIO))
573 return ((int64_t)set_errno(error));
574 return (r.r_vals);
575 }
576
577 if (opcode == PORT_CREATE) {
578 error = port_create(&r.r_val1);
579 if (error)
580 return ((int64_t)set_errno(error));
581 return (r.r_vals);
582 }
583 }
584
585 /* opcodes using port as first argument (a0) */
586
587 if ((fp = getf((int)a0)) == NULL)
588 return ((uintptr_t)set_errno(EBADF));
589
590 if (fp->f_vnode->v_type != VPORT) {
591 releasef((int)a0);
592 return ((uintptr_t)set_errno(EBADFD));
593 }
594
595 pp = VTOEP(fp->f_vnode);
596
597 switch (opcode & PORT_CODE_MASK) {
598 case PORT_GET:
599 {
600 /* see PORT_GETN description */
601 struct timespec timeout;
602
603 port_timer.pgt_flags = PORTGET_ONE;
604 port_timer.pgt_loop = 0;
605 port_timer.pgt_rqtp = NULL;
606 if (a4 != 0) {
607 port_timer.pgt_timeout = &timeout;
608 timeout.tv_sec = (time_t)a2;
609 timeout.tv_nsec = (long)a3;
610 } else {
611 port_timer.pgt_timeout = NULL;
612 }
613 do {
614 nget = 1;
615 error = port_getn(pp, (port_event_t *)a1, 1,
616 (uint_t *)&nget, &port_timer);
617 } while (nget == 0 && error == 0 && port_timer.pgt_loop);
618 break;
619 }
620 case PORT_GETN:
621 {
622 /*
623 * port_getn() can only retrieve own or shareable events from
624 * other processes. The port_getn() function remains in the
625 * kernel until own or shareable events are available or the
626 * timeout elapses.
627 */
628 port_timer.pgt_flags = 0;
629 port_timer.pgt_loop = 0;
630 port_timer.pgt_rqtp = NULL;
631 port_timer.pgt_timeout = (struct timespec *)a4;
632 do {
633 nget = a3;
634 error = port_getn(pp, (port_event_t *)a1, (uint_t)a2,
635 (uint_t *)&nget, &port_timer);
636 } while (nget == 0 && error == 0 && port_timer.pgt_loop);
637 r.r_val1 = nget;
638 r.r_val2 = error;
639 releasef((int)a0);
640 if (error && error != ETIME)
641 return ((int64_t)set_errno(error));
642 return (r.r_vals);
643 }
644 case PORT_ASSOCIATE:
645 {
646 switch ((int)a1) {
647 case PORT_SOURCE_FD:
648 error = port_associate_fd(pp, (int)a1, (uintptr_t)a2,
649 (int)a3, (void *)a4);
650 break;
651 case PORT_SOURCE_FILE:
652 error = port_associate_fop(pp, (int)a1, (uintptr_t)a2,
653 (int)a3, (void *)a4);
654 break;
655 default:
656 error = EINVAL;
657 break;
658 }
659 break;
660 }
661 case PORT_SEND:
662 {
663 /* user-defined events */
664 error = port_send(pp, PORT_SOURCE_USER, (int)a1, (void *)a2);
665 break;
666 }
667 case PORT_DISPATCH:
668 {
669 /*
670 * library events, blocking
671 * Only events of type PORT_SOURCE_AIO or PORT_SOURCE_MQ
672 * are currently allowed.
673 */
674 if ((int)a1 != PORT_SOURCE_AIO && (int)a1 != PORT_SOURCE_MQ) {
675 error = EINVAL;
676 break;
677 }
678 error = port_dispatch_event(pp, (int)opcode, (int)a1, (int)a2,
679 (uintptr_t)a3, (void *)a4);
680 break;
681 }
682 case PORT_DISSOCIATE:
683 {
684 switch ((int)a1) {
685 case PORT_SOURCE_FD:
686 error = port_dissociate_fd(pp, (uintptr_t)a2);
687 break;
688 case PORT_SOURCE_FILE:
689 error = port_dissociate_fop(pp, (uintptr_t)a2);
690 break;
691 default:
692 error = EINVAL;
693 break;
694 }
695 break;
696 }
697 case PORT_ALERT:
698 {
699 if ((int)a2) /* a2 = events */
700 error = port_alert(pp, (int)a1, (int)a2, (void *)a3);
701 else
702 port_remove_alert(&pp->port_queue);
703 break;
704 }
705 default:
706 error = EINVAL;
707 break;
708 }
709
710 releasef((int)a0);
711 if (error)
712 return ((int64_t)set_errno(error));
713 return (r.r_vals);
714 }
715
716 /*
717 * System call to create a port.
718 *
719 * The port_create() function creates a vnode of type VPORT per port.
720 * The port control data is associated with the vnode as vnode private data.
721 * The port_create() function returns an event port file descriptor.
722 */
723 static int
724 port_create(int *fdp)
725 {
726 port_t *pp;
727 vnode_t *vp;
728 struct file *fp;
729 proc_t *p = curproc;
730
731 /* initialize vnode and port private data */
732 pp = kmem_zalloc(sizeof (port_t), KM_SLEEP);
733
734 pp->port_vnode = vn_alloc(KM_SLEEP);
735 vp = EPTOV(pp);
736 vn_setops(vp, port_vnodeops);
737 vp->v_type = VPORT;
738 vp->v_vfsp = &port_vfs;
739 vp->v_data = (caddr_t)pp;
740
741 mutex_enter(&port_control.pc_mutex);
742 /*
743 * Retrieve the maximal number of event ports allowed per system from
744 * the resource control: project.port-max-ids.
745 */
746 mutex_enter(&p->p_lock);
747 if (rctl_test(rc_project_portids, p->p_task->tk_proj->kpj_rctls, p,
748 port_control.pc_nents + 1, RCA_SAFE) & RCT_DENY) {
749 mutex_exit(&p->p_lock);
750 vn_free(vp);
751 kmem_free(pp, sizeof (port_t));
752 mutex_exit(&port_control.pc_mutex);
753 return (EAGAIN);
754 }
755
756 /*
757 * Retrieve the maximal number of events allowed per port from
758 * the resource control: process.port-max-events.
759 */
760 pp->port_max_events = rctl_enforced_value(rc_process_portev,
761 p->p_rctls, p);
762 mutex_exit(&p->p_lock);
763
764 /* allocate a new user file descriptor and a file structure */
765 if (falloc(vp, 0, &fp, fdp)) {
766 /*
767 * If the file table is full, free allocated resources.
768 */
769 vn_free(vp);
770 kmem_free(pp, sizeof (port_t));
771 mutex_exit(&port_control.pc_mutex);
772 return (EMFILE);
773 }
774
775 mutex_exit(&fp->f_tlock);
776
777 pp->port_fd = *fdp;
778 port_control.pc_nents++;
779 p->p_portcnt++;
780 port_kstat.pks_ports.value.ui32++;
781 mutex_exit(&port_control.pc_mutex);
782
783 /* initializes port private data */
784 port_init(pp);
785 /* set user file pointer */
786 setf(*fdp, fp);
787 return (0);
788 }
789
790 /*
791 * port_init() initializes event port specific data
792 */
793 static void
794 port_init(port_t *pp)
795 {
796 port_queue_t *portq;
797 port_ksource_t *pks;
798
799 mutex_init(&pp->port_mutex, NULL, MUTEX_DEFAULT, NULL);
800 portq = &pp->port_queue;
801 mutex_init(&portq->portq_mutex, NULL, MUTEX_DEFAULT, NULL);
802 pp->port_flags |= PORT_INIT;
803
804 /*
805 * If it is not enough memory available to satisfy a user
806 * request using a single port_getn() call then port_getn()
807 * will reduce the size of the list to PORT_MAX_LIST.
808 */
809 pp->port_max_list = port_max_list;
810
811 /* Set timestamp entries required for fstat(2) requests */
812 gethrestime(&pp->port_ctime);
813 pp->port_uid = crgetuid(curproc->p_cred);
814 pp->port_gid = crgetgid(curproc->p_cred);
815
816 /* initialize port queue structs */
817 list_create(&portq->portq_list, sizeof (port_kevent_t),
818 offsetof(port_kevent_t, portkev_node));
819 list_create(&portq->portq_get_list, sizeof (port_kevent_t),
820 offsetof(port_kevent_t, portkev_node));
821 portq->portq_flags = 0;
822 pp->port_pid = curproc->p_pid;
823
824 /* Allocate cache skeleton for PORT_SOURCE_FD events */
825 portq->portq_pcp = kmem_zalloc(sizeof (port_fdcache_t), KM_SLEEP);
826 mutex_init(&portq->portq_pcp->pc_lock, NULL, MUTEX_DEFAULT, NULL);
827
828 /*
829 * Allocate cache skeleton for association of event sources.
830 */
831 mutex_init(&portq->portq_source_mutex, NULL, MUTEX_DEFAULT, NULL);
832 portq->portq_scache = kmem_zalloc(
833 PORT_SCACHE_SIZE * sizeof (port_source_t *), KM_SLEEP);
834
835 /*
836 * pre-associate some kernel sources with this port.
837 * The pre-association is required to create port_source_t
838 * structures for object association.
839 * Some sources can not get associated with a port before the first
840 * object association is requested. Another reason to pre_associate
841 * a particular source with a port is because of performance.
842 */
843
844 for (pks = port_ksource_tab; pks->pks_source != 0; pks++)
845 port_add_ksource_local(pp, pks);
846 }
847
848 /*
849 * The port_add_ksource_local() function is being used to associate
850 * event sources with every new port.
851 * The event sources need to be added to port_ksource_tab[].
852 */
853 static void
854 port_add_ksource_local(port_t *pp, port_ksource_t *pks)
855 {
856 port_source_t *pse;
857 port_source_t **ps;
858
859 mutex_enter(&pp->port_queue.portq_source_mutex);
860 ps = &pp->port_queue.portq_scache[PORT_SHASH(pks->pks_source)];
861 for (pse = *ps; pse != NULL; pse = pse->portsrc_next) {
862 if (pse->portsrc_source == pks->pks_source)
863 break;
864 }
865
866 if (pse == NULL) {
867 /* associate new source with the port */
868 pse = kmem_zalloc(sizeof (port_source_t), KM_SLEEP);
869 pse->portsrc_source = pks->pks_source;
870 pse->portsrc_close = pks->pks_close;
871 pse->portsrc_closearg = pks->pks_closearg;
872 pse->portsrc_cnt = 1;
873
874 pks->pks_portsrc = pse;
875 if (*ps != NULL)
876 pse->portsrc_next = (*ps)->portsrc_next;
877 *ps = pse;
878 }
879 mutex_exit(&pp->port_queue.portq_source_mutex);
880 }
881
882 /*
883 * The port_send() function sends an event of type "source" to a
884 * port. This function is non-blocking. An event can be sent to
885 * a port as long as the number of events per port does not achieve the
886 * maximal allowed number of events. The max. number of events per port is
887 * defined by the resource control process.max-port-events.
888 * This function is used by the port library function port_send()
889 * and port_dispatch(). The port_send(3c) function is part of the
890 * event ports API and submits events of type PORT_SOURCE_USER. The
891 * port_dispatch() function is project private and it is used by library
892 * functions to submit events of other types than PORT_SOURCE_USER
893 * (e.g. PORT_SOURCE_AIO).
894 */
895 static int
896 port_send(port_t *pp, int source, int events, void *user)
897 {
898 port_kevent_t *pev;
899 int error;
900
901 error = port_alloc_event_local(pp, source, PORT_ALLOC_DEFAULT, &pev);
902 if (error)
903 return (error);
904
905 pev->portkev_object = 0;
906 pev->portkev_events = events;
907 pev->portkev_user = user;
908 pev->portkev_callback = NULL;
909 pev->portkev_arg = NULL;
910 pev->portkev_flags = 0;
911
912 port_send_event(pev);
913 return (0);
914 }
915
916 /*
917 * The port_noshare() function returns 0 if the current event was generated
918 * by the same process. Otherwise is returns a value other than 0 and the
919 * event should not be delivered to the current processe.
920 * The port_noshare() function is normally used by the port_dispatch()
921 * function. The port_dispatch() function is project private and can only be
922 * used within the event port project.
923 * Currently the libaio uses the port_dispatch() function to deliver events
924 * of types PORT_SOURCE_AIO.
925 */
926 /* ARGSUSED */
927 static int
928 port_noshare(void *arg, int *events, pid_t pid, int flag, void *evp)
929 {
930 if (flag == PORT_CALLBACK_DEFAULT && curproc->p_pid != pid)
931 return (1);
932 return (0);
933 }
934
935 /*
936 * The port_dispatch_event() function is project private and it is used by
937 * libraries involved in the project to deliver events to the port.
938 * port_dispatch will sleep and wait for enough resources to satisfy the
939 * request, if necessary.
940 * The library can specify if the delivered event is shareable with other
941 * processes (see PORT_SYS_NOSHARE flag).
942 */
943 static int
944 port_dispatch_event(port_t *pp, int opcode, int source, int events,
945 uintptr_t object, void *user)
946 {
947 port_kevent_t *pev;
948 int error;
949
950 error = port_alloc_event_block(pp, source, PORT_ALLOC_DEFAULT, &pev);
951 if (error)
952 return (error);
953
954 pev->portkev_object = object;
955 pev->portkev_events = events;
956 pev->portkev_user = user;
957 pev->portkev_arg = NULL;
958 if (opcode & PORT_SYS_NOSHARE) {
959 pev->portkev_flags = PORT_KEV_NOSHARE;
960 pev->portkev_callback = port_noshare;
961 } else {
962 pev->portkev_flags = 0;
963 pev->portkev_callback = NULL;
964 }
965
966 port_send_event(pev);
967 return (0);
968 }
969
970
971 /*
972 * The port_sendn() function is the kernel implementation of the event
973 * port API function port_sendn(3c).
974 * This function is able to send an event to a list of event ports.
975 */
976 static int
977 port_sendn(int ports[], int errors[], uint_t nent, int events, void *user,
978 uint_t *nget)
979 {
980 port_kevent_t *pev;
981 int errorcnt = 0;
982 int error = 0;
983 int count;
984 int port;
985 int *plist;
986 int *elist = NULL;
987 file_t *fp;
988 port_t *pp;
989
990 if (nent == 0 || nent > port_max_list)
991 return (EINVAL);
992
993 plist = kmem_alloc(nent * sizeof (int), KM_SLEEP);
994 if (copyin((void *)ports, plist, nent * sizeof (int))) {
995 kmem_free(plist, nent * sizeof (int));
996 return (EFAULT);
997 }
998
999 /*
1000 * Scan the list for event port file descriptors and send the
1001 * attached user event data embedded in a event of type
1002 * PORT_SOURCE_USER to every event port in the list.
1003 * If a list entry is not a valid event port then the corresponding
1004 * error code will be stored in the errors[] list with the same
1005 * list offset as in the ports[] list.
1006 */
1007
1008 for (count = 0; count < nent; count++) {
1009 port = plist[count];
1010 if ((fp = getf(port)) == NULL) {
1011 elist = port_errorn(elist, nent, EBADF, count);
1012 errorcnt++;
1013 continue;
1014 }
1015
1016 pp = VTOEP(fp->f_vnode);
1017 if (fp->f_vnode->v_type != VPORT) {
1018 releasef(port);
1019 elist = port_errorn(elist, nent, EBADFD, count);
1020 errorcnt++;
1021 continue;
1022 }
1023
1024 error = port_alloc_event_local(pp, PORT_SOURCE_USER,
1025 PORT_ALLOC_DEFAULT, &pev);
1026 if (error) {
1027 releasef(port);
1028 elist = port_errorn(elist, nent, error, count);
1029 errorcnt++;
1030 continue;
1031 }
1032
1033 pev->portkev_object = 0;
1034 pev->portkev_events = events;
1035 pev->portkev_user = user;
1036 pev->portkev_callback = NULL;
1037 pev->portkev_arg = NULL;
1038 pev->portkev_flags = 0;
1039
1040 port_send_event(pev);
1041 releasef(port);
1042 }
1043 if (errorcnt) {
1044 error = EIO;
1045 if (copyout(elist, (void *)errors, nent * sizeof (int)))
1046 error = EFAULT;
1047 kmem_free(elist, nent * sizeof (int));
1048 }
1049 *nget = nent - errorcnt;
1050 kmem_free(plist, nent * sizeof (int));
1051 return (error);
1052 }
1053
1054 static int *
1055 port_errorn(int *elist, int nent, int error, int index)
1056 {
1057 if (elist == NULL)
1058 elist = kmem_zalloc(nent * sizeof (int), KM_SLEEP);
1059 elist[index] = error;
1060 return (elist);
1061 }
1062
1063 /*
1064 * port_alert()
1065 * The port_alert() funcion is a high priority event and it is always set
1066 * on top of the queue. It is also delivered as single event.
1067 * flags:
1068 * - SET :overwrite current alert data
1069 * - UPDATE:set alert data or return EBUSY if alert mode is already set
1070 *
1071 * - set the ALERT flag
1072 * - wakeup all sleeping threads
1073 */
1074 static int
1075 port_alert(port_t *pp, int flags, int events, void *user)
1076 {
1077 port_queue_t *portq;
1078 portget_t *pgetp;
1079 port_alert_t *pa;
1080
1081 if ((flags & PORT_ALERT_INVALID) == PORT_ALERT_INVALID)
1082 return (EINVAL);
1083
1084 portq = &pp->port_queue;
1085 pa = &portq->portq_alert;
1086 mutex_enter(&portq->portq_mutex);
1087
1088 /* check alert conditions */
1089 if (flags == PORT_ALERT_UPDATE) {
1090 if (portq->portq_flags & PORTQ_ALERT) {
1091 mutex_exit(&portq->portq_mutex);
1092 return (EBUSY);
1093 }
1094 }
1095
1096 /*
1097 * Store alert data in the port to be delivered to threads
1098 * which are using port_get(n) to retrieve events.
1099 */
1100
1101 portq->portq_flags |= PORTQ_ALERT;
1102 pa->portal_events = events; /* alert info */
1103 pa->portal_pid = curproc->p_pid; /* process owner */
1104 pa->portal_object = 0; /* no object */
1105 pa->portal_user = user; /* user alert data */
1106
1107 /* alert and deliver alert data to waiting threads */
1108 pgetp = portq->portq_thread;
1109 if (pgetp == NULL) {
1110 /* no threads waiting for events */
1111 mutex_exit(&portq->portq_mutex);
1112 return (0);
1113 }
1114
1115 /*
1116 * Set waiting threads in alert mode (PORTGET_ALERT)..
1117 * Every thread waiting for events already allocated a portget_t
1118 * structure to sleep on.
1119 * The port alert arguments are stored in the portget_t structure.
1120 * The PORTGET_ALERT flag is set to indicate the thread to return
1121 * immediately with the alert event.
1122 */
1123 do {
1124 if ((pgetp->portget_state & PORTGET_ALERT) == 0) {
1125 pa = &pgetp->portget_alert;
1126 pa->portal_events = events;
1127 pa->portal_object = 0;
1128 pa->portal_user = user;
1129 pgetp->portget_state |= PORTGET_ALERT;
1130 cv_signal(&pgetp->portget_cv);
1131 }
1132 } while ((pgetp = pgetp->portget_next) != portq->portq_thread);
1133 mutex_exit(&portq->portq_mutex);
1134 return (0);
1135 }
1136
1137 /*
1138 * Clear alert state of the port
1139 */
1140 static void
1141 port_remove_alert(port_queue_t *portq)
1142 {
1143 mutex_enter(&portq->portq_mutex);
1144 portq->portq_flags &= ~PORTQ_ALERT;
1145 mutex_exit(&portq->portq_mutex);
1146 }
1147
1148 /*
1149 * The port_getn() function is used to retrieve events from a port.
1150 *
1151 * The port_getn() function returns immediately if there are enough events
1152 * available in the port to satisfy the request or if the port is in alert
1153 * mode (see port_alert(3c)).
1154 * The timeout argument of port_getn(3c) -which is embedded in the
1155 * port_gettimer_t structure- specifies if the system call should block or if it
1156 * should return immediately depending on the number of events available.
1157 * This function is internally used by port_getn(3c) as well as by
1158 * port_get(3c).
1159 */
1160 static int
1161 port_getn(port_t *pp, port_event_t *uevp, uint_t max, uint_t *nget,
1162 port_gettimer_t *pgt)
1163 {
1164 port_queue_t *portq;
1165 port_kevent_t *pev;
1166 port_kevent_t *lev;
1167 int error = 0;
1168 uint_t nmax;
1169 uint_t nevents;
1170 uint_t eventsz;
1171 port_event_t *kevp;
1172 list_t *glist;
1173 uint_t tnent;
1174 int rval;
1175 int blocking = -1;
1176 int timecheck;
1177 int flag;
1178 timespec_t rqtime;
1179 timespec_t *rqtp = NULL;
1180 portget_t *pgetp;
1181 void *results;
1182 model_t model = get_udatamodel();
1183
1184 flag = pgt->pgt_flags;
1185
1186 if (*nget > max && max > 0)
1187 return (EINVAL);
1188
1189 portq = &pp->port_queue;
1190 mutex_enter(&portq->portq_mutex);
1191 if (max == 0) {
1192 /*
1193 * Return number of objects with events.
1194 * The port_block() call is required to synchronize this
1195 * thread with another possible thread, which could be
1196 * retrieving events from the port queue.
1197 */
1198 port_block(portq);
1199 /*
1200 * Check if a second thread is currently retrieving events
1201 * and it is using the temporary event queue.
1202 */
1203 if (portq->portq_tnent) {
1204 /* put remaining events back to the port queue */
1205 port_push_eventq(portq);
1206 }
1207 *nget = portq->portq_nent;
1208 port_unblock(portq);
1209 mutex_exit(&portq->portq_mutex);
1210 return (0);
1211 }
1212
1213 if (uevp == NULL) {
1214 mutex_exit(&portq->portq_mutex);
1215 return (EFAULT);
1216 }
1217 if (*nget == 0) { /* no events required */
1218 mutex_exit(&portq->portq_mutex);
1219 return (0);
1220 }
1221
1222 /* port is being closed ... */
1223 if (portq->portq_flags & PORTQ_CLOSE) {
1224 mutex_exit(&portq->portq_mutex);
1225 return (EBADFD);
1226 }
1227
1228 /* return immediately if port in alert mode */
1229 if (portq->portq_flags & PORTQ_ALERT) {
1230 error = port_get_alert(&portq->portq_alert, uevp);
1231 if (error == 0)
1232 *nget = 1;
1233 mutex_exit(&portq->portq_mutex);
1234 return (error);
1235 }
1236
1237 portq->portq_thrcnt++;
1238
1239 /*
1240 * Now check if the completed events satisfy the
1241 * "wait" requirements of the current thread:
1242 */
1243
1244 if (pgt->pgt_loop) {
1245 /*
1246 * loop entry of same thread
1247 * pgt_loop is set when the current thread returns
1248 * prematurely from this function. That could happen
1249 * when a port is being shared between processes and
1250 * this thread could not find events to return.
1251 * It is not allowed to a thread to retrieve non-shareable
1252 * events generated in other processes.
1253 * PORTQ_WAIT_EVENTS is set when a thread already
1254 * checked the current event queue and no new events
1255 * are added to the queue.
1256 */
1257 if (((portq->portq_flags & PORTQ_WAIT_EVENTS) == 0) &&
1258 (portq->portq_nent >= *nget)) {
1259 /* some new events arrived ...check them */
1260 goto portnowait;
1261 }
1262 rqtp = pgt->pgt_rqtp;
1263 timecheck = pgt->pgt_timecheck;
1264 pgt->pgt_flags |= PORTGET_WAIT_EVENTS;
1265 } else {
1266 /* check if enough events are available ... */
1267 if (portq->portq_nent >= *nget)
1268 goto portnowait;
1269 /*
1270 * There are not enough events available to satisfy
1271 * the request, check timeout value and wait for
1272 * incoming events.
1273 */
1274 error = port_get_timeout(pgt->pgt_timeout, &rqtime, &rqtp,
1275 &blocking, flag);
1276 if (error) {
1277 port_check_return_cond(portq);
1278 mutex_exit(&portq->portq_mutex);
1279 return (error);
1280 }
1281
1282 if (blocking == 0) /* don't block, check fired events */
1283 goto portnowait;
1284
1285 if (rqtp != NULL) {
1286 timespec_t now;
1287 timecheck = timechanged;
1288 gethrestime(&now);
1289 timespecadd(rqtp, &now);
1290 }
1291 }
1292
1293 /* enqueue thread in the list of waiting threads */
1294 pgetp = port_queue_thread(portq, *nget);
1295
1296
1297 /* Wait here until return conditions met */
1298 for (;;) {
1299 if (pgetp->portget_state & PORTGET_ALERT) {
1300 /* reap alert event and return */
1301 error = port_get_alert(&pgetp->portget_alert, uevp);
1302 if (error)
1303 *nget = 0;
1304 else
1305 *nget = 1;
1306 port_dequeue_thread(&pp->port_queue, pgetp);
1307 portq->portq_thrcnt--;
1308 mutex_exit(&portq->portq_mutex);
1309 return (error);
1310 }
1311
1312 /*
1313 * Check if some other thread is already retrieving
1314 * events (portq_getn > 0).
1315 */
1316
1317 if ((portq->portq_getn == 0) &&
1318 ((portq)->portq_nent >= *nget) &&
1319 (!((pgt)->pgt_flags & PORTGET_WAIT_EVENTS) ||
1320 !((portq)->portq_flags & PORTQ_WAIT_EVENTS)))
1321 break;
1322
1323 if (portq->portq_flags & PORTQ_CLOSE) {
1324 error = EBADFD;
1325 break;
1326 }
1327
1328 rval = cv_waituntil_sig(&pgetp->portget_cv, &portq->portq_mutex,
1329 rqtp, timecheck);
1330
1331 if (rval <= 0) {
1332 error = (rval == 0) ? EINTR : ETIME;
1333 break;
1334 }
1335 }
1336
1337 /* take thread out of the wait queue */
1338 port_dequeue_thread(portq, pgetp);
1339
1340 if (error != 0 && (error == EINTR || error == EBADFD ||
1341 (error == ETIME && flag))) {
1342 /* return without events */
1343 port_check_return_cond(portq);
1344 mutex_exit(&portq->portq_mutex);
1345 return (error);
1346 }
1347
1348 portnowait:
1349 /*
1350 * Move port event queue to a temporary event queue .
1351 * New incoming events will be continue be posted to the event queue
1352 * and they will not be considered by the current thread.
1353 * The idea is to avoid lock contentions or an often locking/unlocking
1354 * of the port queue mutex. The contention and performance degradation
1355 * could happen because:
1356 * a) incoming events use the port queue mutex to enqueue new events and
1357 * b) before the event can be delivered to the application it is
1358 * necessary to notify the event sources about the event delivery.
1359 * Sometimes the event sources can require a long time to return and
1360 * the queue mutex would block incoming events.
1361 * During this time incoming events (port_send_event()) do not need
1362 * to awake threads waiting for events. Before the current thread
1363 * returns it will check the conditions to awake other waiting threads.
1364 */
1365 portq->portq_getn++; /* number of threads retrieving events */
1366 port_block(portq); /* block other threads here */
1367 nmax = max < portq->portq_nent ? max : portq->portq_nent;
1368
1369 if (portq->portq_tnent) {
1370 /*
1371 * Move remaining events from previous thread back to the
1372 * port event queue.
1373 */
1374 port_push_eventq(portq);
1375 }
1376 /* move port event queue to a temporary queue */
1377 list_move_tail(&portq->portq_get_list, &portq->portq_list);
1378 glist = &portq->portq_get_list; /* use temporary event queue */
1379 tnent = portq->portq_nent; /* get current number of events */
1380 portq->portq_nent = 0; /* no events in the port event queue */
1381 portq->portq_flags |= PORTQ_WAIT_EVENTS; /* detect incoming events */
1382 mutex_exit(&portq->portq_mutex); /* event queue can be reused now */
1383
1384 if (model == DATAMODEL_NATIVE) {
1385 eventsz = sizeof (port_event_t);
1386
1387 if (nmax == 0) {
1388 kevp = NULL;
1389 } else {
1390 kevp = kmem_alloc(eventsz * nmax, KM_NOSLEEP);
1391 if (kevp == NULL) {
1392 if (nmax > pp->port_max_list)
1393 nmax = pp->port_max_list;
1394 kevp = kmem_alloc(eventsz * nmax, KM_SLEEP);
1395 }
1396 }
1397
1398 results = kevp;
1399 lev = NULL; /* start with first event in the queue */
1400 for (nevents = 0; nevents < nmax; ) {
1401 pev = port_get_kevent(glist, lev);
1402 if (pev == NULL) /* no more events available */
1403 break;
1404 if (pev->portkev_flags & PORT_KEV_FREE) {
1405 /* Just discard event */
1406 list_remove(glist, pev);
1407 pev->portkev_flags &= ~(PORT_CLEANUP_DONE);
1408 if (PORT_FREE_EVENT(pev))
1409 port_free_event_local(pev, B_TRUE);
1410 tnent--;
1411 continue;
1412 }
1413
1414 /* move event data to copyout list */
1415 if (port_copy_event(&kevp[nevents], pev, glist)) {
1416 /*
1417 * Event can not be delivered to the
1418 * current process.
1419 */
1420 if (lev != NULL)
1421 list_insert_after(glist, lev, pev);
1422 else
1423 list_insert_head(glist, pev);
1424 lev = pev; /* last checked event */
1425 } else {
1426 nevents++; /* # of events ready */
1427 }
1428 }
1429 #ifdef _SYSCALL32_IMPL
1430 } else {
1431 port_event32_t *kevp32;
1432
1433 eventsz = sizeof (port_event32_t);
1434
1435 if (nmax == 0) {
1436 kevp32 = NULL;
1437 } else {
1438 kevp32 = kmem_alloc(eventsz * nmax, KM_NOSLEEP);
1439 if (kevp32 == NULL) {
1440 if (nmax > pp->port_max_list)
1441 nmax = pp->port_max_list;
1442 kevp32 = kmem_alloc(eventsz * nmax, KM_SLEEP);
1443 }
1444 }
1445
1446 results = kevp32;
1447 lev = NULL; /* start with first event in the queue */
1448 for (nevents = 0; nevents < nmax; ) {
1449 pev = port_get_kevent(glist, lev);
1450 if (pev == NULL) /* no more events available */
1451 break;
1452 if (pev->portkev_flags & PORT_KEV_FREE) {
1453 /* Just discard event */
1454 list_remove(glist, pev);
1455 pev->portkev_flags &= ~(PORT_CLEANUP_DONE);
1456 if (PORT_FREE_EVENT(pev))
1457 port_free_event_local(pev, B_TRUE);
1458 tnent--;
1459 continue;
1460 }
1461
1462 /* move event data to copyout list */
1463 if (port_copy_event32(&kevp32[nevents], pev, glist)) {
1464 /*
1465 * Event can not be delivered to the
1466 * current process.
1467 */
1468 if (lev != NULL)
1469 list_insert_after(glist, lev, pev);
1470 else
1471 list_insert_head(glist, pev);
1472 lev = pev; /* last checked event */
1473 } else {
1474 nevents++; /* # of events ready */
1475 }
1476 }
1477 #endif /* _SYSCALL32_IMPL */
1478 }
1479
1480 /*
1481 * Remember number of remaining events in the temporary event queue.
1482 */
1483 portq->portq_tnent = tnent - nevents;
1484
1485 /*
1486 * Work to do before return :
1487 * - push list of remaining events back to the top of the standard
1488 * port queue.
1489 * - if this is the last thread calling port_get(n) then wakeup the
1490 * thread waiting on close(2).
1491 * - check for a deferred cv_signal from port_send_event() and wakeup
1492 * the sleeping thread.
1493 */
1494
1495 mutex_enter(&portq->portq_mutex);
1496 port_unblock(portq);
1497 if (portq->portq_tnent) {
1498 /*
1499 * move remaining events in the temporary event queue back
1500 * to the port event queue
1501 */
1502 port_push_eventq(portq);
1503 }
1504 portq->portq_getn--; /* update # of threads retrieving events */
1505 if (--portq->portq_thrcnt == 0) { /* # of threads waiting ... */
1506 /* Last thread => check close(2) conditions ... */
1507 if (portq->portq_flags & PORTQ_CLOSE) {
1508 cv_signal(&portq->portq_closecv);
1509 mutex_exit(&portq->portq_mutex);
1510 kmem_free(results, eventsz * nmax);
1511 /* do not copyout events */
1512 *nget = 0;
1513 return (EBADFD);
1514 }
1515 } else if (portq->portq_getn == 0) {
1516 /*
1517 * no other threads retrieving events ...
1518 * check wakeup conditions of sleeping threads
1519 */
1520 if ((portq->portq_thread != NULL) &&
1521 (portq->portq_nent >= portq->portq_nget))
1522 cv_signal(&portq->portq_thread->portget_cv);
1523 }
1524
1525 /*
1526 * Check PORTQ_POLLIN here because the current thread set temporarily
1527 * the number of events in the queue to zero.
1528 */
1529 if (portq->portq_flags & PORTQ_POLLIN) {
1530 portq->portq_flags &= ~PORTQ_POLLIN;
1531 mutex_exit(&portq->portq_mutex);
1532 pollwakeup(&pp->port_pollhd, POLLIN);
1533 } else {
1534 mutex_exit(&portq->portq_mutex);
1535 }
1536
1537 /* now copyout list of user event structures to user space */
1538 if (nevents) {
1539 if (copyout(results, uevp, nevents * eventsz))
1540 error = EFAULT;
1541 }
1542 kmem_free(results, eventsz * nmax);
1543
1544 if (nevents == 0 && error == 0 && pgt->pgt_loop == 0 && blocking != 0) {
1545 /* no events retrieved: check loop conditions */
1546 if (blocking == -1) {
1547 /* no timeout checked */
1548 error = port_get_timeout(pgt->pgt_timeout,
1549 &pgt->pgt_rqtime, &rqtp, &blocking, flag);
1550 if (error) {
1551 *nget = nevents;
1552 return (error);
1553 }
1554 if (rqtp != NULL) {
1555 timespec_t now;
1556 pgt->pgt_timecheck = timechanged;
1557 gethrestime(&now);
1558 timespecadd(&pgt->pgt_rqtime, &now);
1559 }
1560 pgt->pgt_rqtp = rqtp;
1561 } else {
1562 /* timeout already checked -> remember values */
1563 pgt->pgt_rqtp = rqtp;
1564 if (rqtp != NULL) {
1565 pgt->pgt_timecheck = timecheck;
1566 pgt->pgt_rqtime = *rqtp;
1567 }
1568 }
1569 if (blocking)
1570 /* timeout remaining */
1571 pgt->pgt_loop = 1;
1572 }
1573
1574 /* set number of user event structures completed */
1575 *nget = nevents;
1576 return (error);
1577 }
1578
1579 /*
1580 * 1. copy kernel event structure to user event structure.
1581 * 2. PORT_KEV_WIRED event structures will be reused by the "source"
1582 * 3. Remove PORT_KEV_DONEQ flag (event removed from the event queue)
1583 * 4. Other types of event structures can be delivered back to the port cache
1584 * (port_free_event_local()).
1585 * 5. The event source callback function is the last opportunity for the
1586 * event source to update events, to free local resources associated with
1587 * the event or to deny the delivery of the event.
1588 */
1589 static int
1590 port_copy_event(port_event_t *puevp, port_kevent_t *pkevp, list_t *list)
1591 {
1592 int free_event = 0;
1593 int flags;
1594 int error;
1595
1596 puevp->portev_source = pkevp->portkev_source;
1597 puevp->portev_object = pkevp->portkev_object;
1598 puevp->portev_user = pkevp->portkev_user;
1599 puevp->portev_events = pkevp->portkev_events;
1600
1601 /* remove event from the queue */
1602 list_remove(list, pkevp);
1603
1604 /*
1605 * Events of type PORT_KEV_WIRED remain allocated by the
1606 * event source.
1607 */
1608 flags = pkevp->portkev_flags;
1609 if (pkevp->portkev_flags & PORT_KEV_WIRED)
1610 pkevp->portkev_flags &= ~PORT_KEV_DONEQ;
1611 else
1612 free_event = 1;
1613
1614 if (pkevp->portkev_callback) {
1615 error = (*pkevp->portkev_callback)(pkevp->portkev_arg,
1616 &puevp->portev_events, pkevp->portkev_pid,
1617 PORT_CALLBACK_DEFAULT, pkevp);
1618
1619 if (error) {
1620 /*
1621 * Event can not be delivered.
1622 * Caller must reinsert the event into the queue.
1623 */
1624 pkevp->portkev_flags = flags;
1625 return (error);
1626 }
1627 }
1628 if (free_event)
1629 port_free_event_local(pkevp, B_TRUE);
1630 return (0);
1631 }
1632
1633 #ifdef _SYSCALL32_IMPL
1634 /*
1635 * 1. copy kernel event structure to user event structure.
1636 * 2. PORT_KEV_WIRED event structures will be reused by the "source"
1637 * 3. Remove PORT_KEV_DONEQ flag (event removed from the event queue)
1638 * 4. Other types of event structures can be delivered back to the port cache
1639 * (port_free_event_local()).
1640 * 5. The event source callback function is the last opportunity for the
1641 * event source to update events, to free local resources associated with
1642 * the event or to deny the delivery of the event.
1643 */
1644 static int
1645 port_copy_event32(port_event32_t *puevp, port_kevent_t *pkevp, list_t *list)
1646 {
1647 int free_event = 0;
1648 int error;
1649 int flags;
1650
1651 puevp->portev_source = pkevp->portkev_source;
1652 puevp->portev_object = (daddr32_t)pkevp->portkev_object;
1653 puevp->portev_user = (caddr32_t)(uintptr_t)pkevp->portkev_user;
1654 puevp->portev_events = pkevp->portkev_events;
1655
1656 /* remove event from the queue */
1657 list_remove(list, pkevp);
1658
1659 /*
1660 * Events if type PORT_KEV_WIRED remain allocated by the
1661 * sub-system (source).
1662 */
1663
1664 flags = pkevp->portkev_flags;
1665 if (pkevp->portkev_flags & PORT_KEV_WIRED)
1666 pkevp->portkev_flags &= ~PORT_KEV_DONEQ;
1667 else
1668 free_event = 1;
1669
1670 if (pkevp->portkev_callback != NULL) {
1671 error = (*pkevp->portkev_callback)(pkevp->portkev_arg,
1672 &puevp->portev_events, pkevp->portkev_pid,
1673 PORT_CALLBACK_DEFAULT, pkevp);
1674 if (error) {
1675 /*
1676 * Event can not be delivered.
1677 * Caller must reinsert the event into the queue.
1678 */
1679 pkevp->portkev_flags = flags;
1680 return (error);
1681 }
1682 }
1683 if (free_event)
1684 port_free_event_local(pkevp, B_TRUE);
1685 return (0);
1686 }
1687 #endif /* _SYSCALL32_IMPL */
1688
1689 /*
1690 * copyout alert event.
1691 */
1692 static int
1693 port_get_alert(port_alert_t *pa, port_event_t *uevp)
1694 {
1695 model_t model = get_udatamodel();
1696
1697 /* copyout alert event structures to user space */
1698 if (model == DATAMODEL_NATIVE) {
1699 port_event_t uev;
1700 uev.portev_source = PORT_SOURCE_ALERT;
1701 uev.portev_object = pa->portal_object;
1702 uev.portev_events = pa->portal_events;
1703 uev.portev_user = pa->portal_user;
1704 if (copyout(&uev, uevp, sizeof (port_event_t)))
1705 return (EFAULT);
1706 #ifdef _SYSCALL32_IMPL
1707 } else {
1708 port_event32_t uev32;
1709 uev32.portev_source = PORT_SOURCE_ALERT;
1710 uev32.portev_object = (daddr32_t)pa->portal_object;
1711 uev32.portev_events = pa->portal_events;
1712 uev32.portev_user = (daddr32_t)(uintptr_t)pa->portal_user;
1713 if (copyout(&uev32, uevp, sizeof (port_event32_t)))
1714 return (EFAULT);
1715 #endif /* _SYSCALL32_IMPL */
1716 }
1717 return (0);
1718 }
1719
1720 /*
1721 * Check return conditions :
1722 * - pending port close(2)
1723 * - threads waiting for events
1724 */
1725 static void
1726 port_check_return_cond(port_queue_t *portq)
1727 {
1728 ASSERT(MUTEX_HELD(&portq->portq_mutex));
1729 portq->portq_thrcnt--;
1730 if (portq->portq_flags & PORTQ_CLOSE) {
1731 if (portq->portq_thrcnt == 0)
1732 cv_signal(&portq->portq_closecv);
1733 else
1734 cv_signal(&portq->portq_thread->portget_cv);
1735 }
1736 }
1737
1738 /*
1739 * The port_get_kevent() function returns
1740 * - the event located at the head of the queue if 'last' pointer is NULL
1741 * - the next event after the event pointed by 'last'
1742 * The caller of this function is responsible for the integrity of the queue
1743 * in use:
1744 * - port_getn() is using a temporary queue protected with port_block().
1745 * - port_close_events() is working on the global event queue and protects
1746 * the queue with portq->portq_mutex.
1747 */
1748 port_kevent_t *
1749 port_get_kevent(list_t *list, port_kevent_t *last)
1750 {
1751 if (last == NULL)
1752 return (list_head(list));
1753 else
1754 return (list_next(list, last));
1755 }
1756
1757 /*
1758 * The port_get_timeout() function gets the timeout data from user space
1759 * and converts that info into a corresponding internal representation.
1760 * The kerneldata flag means that the timeout data is already loaded.
1761 */
1762 static int
1763 port_get_timeout(timespec_t *timeout, timespec_t *rqtime, timespec_t **rqtp,
1764 int *blocking, int kerneldata)
1765 {
1766 model_t model = get_udatamodel();
1767
1768 *rqtp = NULL;
1769 if (timeout == NULL) {
1770 *blocking = 1;
1771 return (0);
1772 }
1773
1774 if (kerneldata) {
1775 *rqtime = *timeout;
1776 } else {
1777 if (model == DATAMODEL_NATIVE) {
1778 if (copyin(timeout, rqtime, sizeof (*rqtime)))
1779 return (EFAULT);
1780 #ifdef _SYSCALL32_IMPL
1781 } else {
1782 timespec32_t wait_time_32;
1783 if (copyin(timeout, &wait_time_32,
1784 sizeof (wait_time_32)))
1785 return (EFAULT);
1786 TIMESPEC32_TO_TIMESPEC(rqtime, &wait_time_32);
1787 #endif /* _SYSCALL32_IMPL */
1788 }
1789 }
1790
1791 if (rqtime->tv_sec == 0 && rqtime->tv_nsec == 0) {
1792 *blocking = 0;
1793 return (0);
1794 }
1795
1796 if (rqtime->tv_sec < 0 ||
1797 rqtime->tv_nsec < 0 || rqtime->tv_nsec >= NANOSEC)
1798 return (EINVAL);
1799
1800 *rqtp = rqtime;
1801 *blocking = 1;
1802 return (0);
1803 }
1804
1805 /*
1806 * port_queue_thread()
1807 * Threads requiring more events than available will be put in a wait queue.
1808 * There is a "thread wait queue" per port.
1809 * Threads requiring less events get a higher priority than others and they
1810 * will be awoken first.
1811 */
1812 static portget_t *
1813 port_queue_thread(port_queue_t *portq, uint_t nget)
1814 {
1815 portget_t *pgetp;
1816 portget_t *ttp;
1817 portget_t *htp;
1818
1819 pgetp = kmem_zalloc(sizeof (portget_t), KM_SLEEP);
1820 pgetp->portget_nget = nget;
1821 pgetp->portget_pid = curproc->p_pid;
1822 if (portq->portq_thread == NULL) {
1823 /* first waiting thread */
1824 portq->portq_thread = pgetp;
1825 portq->portq_nget = nget;
1826 pgetp->portget_prev = pgetp;
1827 pgetp->portget_next = pgetp;
1828 return (pgetp);
1829 }
1830
1831 /*
1832 * thread waiting for less events will be set on top of the queue.
1833 */
1834 ttp = portq->portq_thread;
1835 htp = ttp;
1836 for (;;) {
1837 if (nget <= ttp->portget_nget)
1838 break;
1839 if (htp == ttp->portget_next)
1840 break; /* last event */
1841 ttp = ttp->portget_next;
1842 }
1843
1844 /* add thread to the queue */
1845 pgetp->portget_next = ttp;
1846 pgetp->portget_prev = ttp->portget_prev;
1847 ttp->portget_prev->portget_next = pgetp;
1848 ttp->portget_prev = pgetp;
1849 if (portq->portq_thread == ttp)
1850 portq->portq_thread = pgetp;
1851 portq->portq_nget = portq->portq_thread->portget_nget;
1852 return (pgetp);
1853 }
1854
1855 /*
1856 * Take thread out of the queue.
1857 */
1858 static void
1859 port_dequeue_thread(port_queue_t *portq, portget_t *pgetp)
1860 {
1861 if (pgetp->portget_next == pgetp) {
1862 /* last (single) waiting thread */
1863 portq->portq_thread = NULL;
1864 portq->portq_nget = 0;
1865 } else {
1866 pgetp->portget_prev->portget_next = pgetp->portget_next;
1867 pgetp->portget_next->portget_prev = pgetp->portget_prev;
1868 if (portq->portq_thread == pgetp)
1869 portq->portq_thread = pgetp->portget_next;
1870 portq->portq_nget = portq->portq_thread->portget_nget;
1871 }
1872 kmem_free(pgetp, sizeof (portget_t));
1873 }
1874
1875 /*
1876 * Set up event port kstats.
1877 */
1878 static void
1879 port_kstat_init()
1880 {
1881 kstat_t *ksp;
1882 uint_t ndata;
1883
1884 ndata = sizeof (port_kstat) / sizeof (kstat_named_t);
1885 ksp = kstat_create("portfs", 0, "Event Ports", "misc",
1886 KSTAT_TYPE_NAMED, ndata, KSTAT_FLAG_VIRTUAL);
1887 if (ksp) {
1888 ksp->ks_data = &port_kstat;
1889 kstat_install(ksp);
1890 }
1891 }