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--- old/usr/src/uts/common/os/ipc.c
+++ new/usr/src/uts/common/os/ipc.c
1 1 /*
2 2 * CDDL HEADER START
3 3 *
4 4 * The contents of this file are subject to the terms of the
5 5 * Common Development and Distribution License (the "License").
6 6 * You may not use this file except in compliance with the License.
7 7 *
8 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 9 * or http://www.opensolaris.org/os/licensing.
10 10 * See the License for the specific language governing permissions
11 11 * and limitations under the License.
12 12 *
13 13 * When distributing Covered Code, include this CDDL HEADER in each
14 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 15 * If applicable, add the following below this CDDL HEADER, with the
16 16 * fields enclosed by brackets "[]" replaced with your own identifying
17 17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 18 *
19 19 * CDDL HEADER END
20 20 */
21 21 /*
22 22 * Copyright (c) 1988, 2010, Oracle and/or its affiliates. All rights reserved.
23 23 */
24 24
25 25 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
26 26 /* All Rights Reserved */
27 27
28 28
29 29 /*
30 30 * Common Inter-Process Communication routines.
31 31 *
32 32 * Overview
33 33 * --------
34 34 *
35 35 * The System V inter-process communication (IPC) facilities provide
36 36 * three services, message queues, semaphore arrays, and shared memory
37 37 * segments, which are mananged using filesystem-like namespaces.
38 38 * Unlike a filesystem, these namespaces aren't mounted and accessible
39 39 * via a path -- a special API is used to interact with the different
40 40 * facilities (nothing precludes a VFS-based interface, but the
41 41 * standards require the special APIs). Furthermore, these special
42 42 * APIs don't use file descriptors, nor do they have an equivalent.
43 43 * This means that every operation which acts on an object needs to
44 44 * perform the quivalent of a lookup, which in turn means that every
45 45 * operation can fail if the specified object doesn't exist in the
46 46 * facility's namespace.
47 47 *
48 48 * Objects
49 49 * -------
50 50 *
51 51 * Each object in a namespace has a unique ID, which is assigned by the
52 52 * system and is used to identify the object when performing operations
53 53 * on it. An object can also have a key, which is selected by the user
54 54 * at allocation time and is used as a primitive rendezvous mechanism.
55 55 * An object without a key is said to have a "private" key.
56 56 *
57 57 * To perform an operation on an object given its key, one must first
58 58 * perform a lookup and obtain its ID. The ID is then used to identify
59 59 * the object when performing the operation. If the object has a
60 60 * private key, the ID must be known or obtained by other means.
61 61 *
62 62 * Each object in the namespace has a creator uid and gid, as well as
63 63 * an owner uid and gid. Both are initialized with the ruid and rgid
64 64 * of the process which created the object. The creator or current
65 65 * owner has the ability to change the owner of the object.
66 66 *
67 67 * Each object in the namespace has a set of file-like permissions,
68 68 * which, in conjunction with the creator and owner uid and gid,
69 69 * control read and write access to the object (execute is ignored).
70 70 *
71 71 * Each object also has a creator project and zone, which are used to
72 72 * account for its resource usage.
73 73 *
74 74 * Operations
75 75 * ----------
76 76 *
77 77 * There are five operations which all three facilities have in
78 78 * common: GET, SET, STAT, RMID, and IDS.
79 79 *
80 80 * GET, like open, is used to allocate a new object or obtain an
81 81 * existing one (using its key). It takes a key, a set of flags and
82 82 * mode bits, and optionally facility-specific arguments. If the key
83 83 * is IPC_PRIVATE, a new object with the requested mode bits and
84 84 * facility-specific attributes is created. If the key isn't
85 85 * IPC_PRIVATE, the GET will attempt to look up the specified key and
86 86 * either return that or create a new key depending on the state of the
87 87 * IPC_CREAT and IPC_EXCL flags, much like open. If GET needs to
88 88 * allocate an object, it can fail if there is insufficient space in
89 89 * the namespace (the maximum number of ids for the facility has been
90 90 * exceeded) or if the facility-specific initialization fails. If GET
91 91 * finds an object it can return, it can still fail if that object's
92 92 * permissions or facility-specific attributes are less than those
93 93 * requested.
94 94 *
95 95 * SET is used to adjust facility-specific parameters of an object, in
96 96 * addition to the owner uid and gid, and mode bits. It can fail if
97 97 * the caller isn't the creator or owner.
98 98 *
99 99 * STAT is used to obtain information about an object including the
100 100 * general attributes object described as well as facility-specific
101 101 * information. It can fail if the caller doesn't have read
102 102 * permission.
103 103 *
104 104 * RMID removes an object from the namespace. Subsequent operations
105 105 * using the object's ID or key will fail (until another object is
106 106 * created with the same key or ID). Since an RMID may be performed
107 107 * asynchronously with other operations, it is possible that other
108 108 * threads and/or processes will have references to the object. While
109 109 * a facility may have actions which need to be performed at RMID time,
110 110 * only when all references are dropped can the object be destroyed.
111 111 * RMID will fail if the caller isn't the creator or owner.
112 112 *
113 113 * IDS obtains a list of all IDs in a facility's namespace. There are
114 114 * no facility-specific behaviors of IDS.
115 115 *
116 116 * Design
117 117 * ------
118 118 *
119 119 * Because some IPC facilities provide services whose operations must
120 120 * scale, a mechanism which allows fast, concurrent access to
121 121 * individual objects is needed. Of primary importance is object
122 122 * lookup based on ID (SET, STAT, others). Allocation (GET),
123 123 * deallocation (RMID), ID enumeration (IDS), and key lookups (GET) are
124 124 * lesser concerns, but should be implemented in such a way that ID
125 125 * lookup isn't affected (at least not in the common case).
126 126 *
127 127 * Starting from the bottom up, each object is represented by a
128 128 * structure, the first member of which must be a kipc_perm_t. The
129 129 * kipc_perm_t contains the information described above in "Objects", a
130 130 * reference count (since the object may continue to exist after it has
131 131 * been removed from the namespace), as well as some additional
132 132 * metadata used to manage data structure membership. These objects
133 133 * are dynamically allocated.
134 134 *
135 135 * Above the objects is a power-of-two sized table of ID slots. Each
136 136 * slot contains a pointer to an object, a sequence number, and a
137 137 * lock. An object's ID is a function of its slot's index in the table
138 138 * and its slot's sequence number. Every time a slot is released (via
139 139 * RMID) its sequence number is increased. Strictly speaking, the
140 140 * sequence number is unnecessary. However, checking the sequence
141 141 * number after a lookup provides a certain degree of robustness
142 142 * against the use of stale IDs (useful since nothing else does). When
143 143 * the table fills up, it is resized (see Locking, below).
144 144 *
145 145 * Of an ID's 31 bits (an ID is, as defined by the standards, a signed
146 146 * int) the top IPC_SEQ_BITS are used for the sequence number with the
147 147 * remainder holding the index into the table. The size of the table
148 148 * is therefore bounded at 2 ^ (31 - IPC_SEQ_BITS) slots.
149 149 *
150 150 * Managing this table is the ipc_service structure. It contains a
151 151 * pointer to the dynamically allocated ID table, a namespace-global
152 152 * lock, an id_space for managing the free space in the table, and
153 153 * sundry other metadata necessary for the maintenance of the
154 154 * namespace. An AVL tree of all keyed objects in the table (sorted by
155 155 * key) is used for key lookups. An unordered doubly linked list of
156 156 * all objects in the namespace (keyed or not) is maintained to
157 157 * facilitate ID enumeration.
158 158 *
159 159 * To help visualize these relationships, here's a picture of a
160 160 * namespace with a table of size 8 containing three objects
161 161 * (IPC_SEQ_BITS = 28):
162 162 *
163 163 *
164 164 * +-ipc_service_t--+
165 165 * | table *---\
166 166 * | keys *---+----------------------\
167 167 * | all ids *--\| |
168 168 * | | || |
169 169 * +----------------+ || |
170 170 * || |
171 171 * /-------------------/| |
172 172 * | /---------------/ |
173 173 * | | |
174 174 * | v |
175 175 * | +-0------+-1------+-2------+-3------+-4--+---+-5------+-6------+-7------+
176 176 * | | Seq=3 | | | Seq=1 | : | | | Seq=6 |
177 177 * | | | | | | : | | | |
178 178 * | +-*------+--------+--------+-*------+----+---+--------+--------+-*------+
179 179 * | | | | |
180 180 * | | /---/ | /----------------/
181 181 * | | | | |
182 182 * | v v | v
183 183 * | +-kipc_perm_t-+ +-kipc_perm_t-+ | +-kipc_perm_t-+
184 184 * | | id=0x30 | | id=0x13 | | | id=0x67 |
185 185 * | | key=0xfeed | | key=0xbeef | | | key=0xcafe |
186 186 * \->| [list] |<------>| [list] |<------>| [list] |
187 187 * /->| [avl left] x /--->| [avl left] x \--->| [avl left] *---\
188 188 * | | [avl right] x | | [avl right] x | [avl right] *---+-\
189 189 * | | | | | | | | | |
190 190 * | +-------------+ | +-------------+ +-------------+ | |
191 191 * | \---------------------------------------------/ |
192 192 * \--------------------------------------------------------------------/
193 193 *
194 194 * Locking
195 195 * -------
196 196 *
197 197 * There are three locks (or sets of locks) which are used to ensure
198 198 * correctness: the slot locks, the namespace lock, and p_lock (needed
199 199 * when checking resource controls). Their ordering is
200 200 *
201 201 * namespace lock -> slot lock 0 -> ... -> slot lock t -> p_lock
202 202 *
203 203 * Generally speaking, the namespace lock is used to protect allocation
204 204 * and removal from the namespace, ID enumeration, and resizing the ID
205 205 * table. Specifically:
206 206 *
207 207 * - write access to all fields of the ipc_service structure
208 208 * - read access to all variable fields of ipc_service except
209 209 * ipcs_tabsz (table size) and ipcs_table (the table pointer)
210 210 * - read/write access to ipc_avl, ipc_list in visible objects'
211 211 * kipc_perm structures (i.e. objects which have been removed from
212 212 * the namespace don't have this restriction)
213 213 * - write access to ipct_seq and ipct_data in the table entries
214 214 *
215 215 * A slot lock by itself is meaningless (except when resizing). Of
216 216 * greater interest conceptually is the notion of an ID lock -- a
217 217 * "virtual lock" which refers to whichever slot lock an object's ID
218 218 * currently hashes to.
219 219 *
220 220 * An ID lock protects all objects with that ID. Normally there will
221 221 * only be one such object: the one pointed to by the locked slot.
222 222 * However, if an object is removed from the namespace but retains
223 223 * references (e.g. an attached shared memory segment which has been
224 224 * RMIDed), it continues to use the lock associated with its original
225 225 * ID. While this can result in increased contention, operations which
226 226 * require taking the ID lock of removed objects are infrequent.
227 227 *
228 228 * Specifically, an ID lock protects the contents of an object's
229 229 * structure, including the contents of the embedded kipc_perm
230 230 * structure (but excluding those fields protected by the namespace
231 231 * lock). It also protects the ipct_seq and ipct_data fields in its
232 232 * slot (it is really a slot lock, after all).
233 233 *
234 234 * Recall that the table is resizable. To avoid requiring every ID
235 235 * lookup to take a global lock, a scheme much like that employed for
236 236 * file descriptors (see the comment above UF_ENTER in user.h) is
237 237 * used. Note that the sequence number and data pointer are protected
238 238 * by both the namespace lock and their slot lock. When the table is
239 239 * resized, the following operations take place:
240 240 *
241 241 * 1) A new table is allocated.
242 242 * 2) The global lock is taken.
243 243 * 3) All old slots are locked, in order.
244 244 * 4) The first half of the new slots are locked.
245 245 * 5) All table entries are copied to the new table, and cleared from
246 246 * the old table.
247 247 * 6) The ipc_service structure is updated to point to the new table.
248 248 * 7) The ipc_service structure is updated with the new table size.
249 249 * 8) All slot locks (old and new) are dropped.
250 250 *
251 251 * Because the slot locks are embedded in the table, ID lookups and
252 252 * other operations which require taking an slot lock need to verify
253 253 * that the lock taken wasn't part of a stale table. This is
254 254 * accomplished by checking the table size before and after
255 255 * dereferencing the table pointer and taking the lock: if the size
256 256 * changes, the lock must be dropped and reacquired. It is this
257 257 * additional work which distinguishes an ID lock from a slot lock.
258 258 *
259 259 * Because we can't guarantee that threads aren't accessing the old
260 260 * tables' locks, they are never deallocated. To prevent spurious
261 261 * reports of memory leaks, a pointer to the discarded table is stored
262 262 * in the new one in step 5. (Theoretically ipcs_destroy will delete
263 263 * the discarded tables, but it is only ever called from a failed _init
264 264 * invocation; i.e. when there aren't any.)
265 265 *
266 266 * Interfaces
267 267 * ----------
268 268 *
269 269 * The following interfaces are provided by the ipc module for use by
270 270 * the individual IPC facilities:
271 271 *
272 272 * ipcperm_access
273 273 *
274 274 * Given an object and a cred structure, determines if the requested
275 275 * access type is allowed.
276 276 *
277 277 * ipcperm_set, ipcperm_stat,
278 278 * ipcperm_set64, ipcperm_stat64
279 279 *
280 280 * Performs the common portion of an STAT or SET operation. All
281 281 * (except stat and stat64) can fail, so they should be called before
282 282 * any facility-specific non-reversible changes are made to an
283 283 * object. Similarly, the set operations have side effects, so they
284 284 * should only be called once the possibility of a facility-specific
285 285 * failure is eliminated.
286 286 *
287 287 * ipcs_create
288 288 *
289 289 * Creates an IPC namespace for use by an IPC facility.
290 290 *
291 291 * ipcs_destroy
292 292 *
293 293 * Destroys an IPC namespace.
294 294 *
295 295 * ipcs_lock, ipcs_unlock
296 296 *
297 297 * Takes the namespace lock. Ideally such access wouldn't be
298 298 * necessary, but there may be facility-specific data protected by
299 299 * this lock (e.g. project-wide resource consumption).
300 300 *
301 301 * ipc_lock
302 302 *
303 303 * Takes the lock associated with an ID. Can't fail.
304 304 *
305 305 * ipc_relock
306 306 *
307 307 * Like ipc_lock, but takes a pointer to a held lock. Drops the lock
308 308 * unless it is the one that would have been returned by ipc_lock.
309 309 * Used after calls to cv_wait.
310 310 *
311 311 * ipc_lookup
312 312 *
313 313 * Performs an ID lookup, returns with the ID lock held. Fails if
314 314 * the ID doesn't exist in the namespace.
315 315 *
316 316 * ipc_hold
317 317 *
318 318 * Takes a reference on an object.
319 319 *
320 320 * ipc_rele
321 321 *
322 322 * Releases a reference on an object, and drops the object's lock.
323 323 * Calls the object's destructor if last reference is being
324 324 * released.
325 325 *
326 326 * ipc_rele_locked
327 327 *
328 328 * Releases a reference on an object. Doesn't drop lock, and may
329 329 * only be called when there is more than one reference to the
330 330 * object.
331 331 *
332 332 * ipc_get, ipc_commit_begin, ipc_commit_end, ipc_cleanup
333 333 *
334 334 * Components of a GET operation. ipc_get performs a key lookup,
335 335 * allocating an object if the key isn't found (returning with the
336 336 * namespace lock and p_lock held), and returning the existing object
337 337 * if it is (with the object lock held). ipc_get doesn't modify the
338 338 * namespace.
339 339 *
340 340 * ipc_commit_begin begins the process of inserting an object
341 341 * allocated by ipc_get into the namespace, and can fail. If
342 342 * successful, it returns with the namespace lock and p_lock held.
343 343 * ipc_commit_end completes the process of inserting an object into
344 344 * the namespace and can't fail. The facility can call ipc_cleanup
345 345 * at any time following a successful ipc_get and before
346 346 * ipc_commit_end or a failed ipc_commit_begin to fail the
347 347 * allocation. Pseudocode for the suggested GET implementation:
348 348 *
349 349 * top:
350 350 *
351 351 * ipc_get
352 352 *
353 353 * if failure
354 354 * return
355 355 *
356 356 * if found {
357 357 *
358 358 * if object meets criteria
359 359 * unlock object and return success
360 360 * else
361 361 * unlock object and return failure
362 362 *
363 363 * } else {
364 364 *
365 365 * perform resource control tests
366 366 * drop namespace lock, p_lock
367 367 * if failure
368 368 * ipc_cleanup
369 369 *
370 370 * perform facility-specific initialization
371 371 * if failure {
372 372 * facility-specific cleanup
373 373 * ipc_cleanup
374 374 * }
375 375 *
376 376 * ( At this point the object should be destructible using the
377 377 * destructor given to ipcs_create )
378 378 *
379 379 * ipc_commit_begin
380 380 * if retry
381 381 * goto top
382 382 * else if failure
383 383 * return
384 384 *
385 385 * perform facility-specific resource control tests/allocations
386 386 * if failure
387 387 * ipc_cleanup
388 388 *
389 389 * ipc_commit_end
390 390 * perform any infallible post-creation actions, unlock, and return
391 391 *
392 392 * }
393 393 *
394 394 * ipc_rmid
395 395 *
396 396 * Performs the common portion of an RMID operation -- looks up an ID
397 397 * removes it, and calls the a facility-specific function to do
398 398 * RMID-time cleanup on the private portions of the object.
399 399 *
400 400 * ipc_ids
401 401 *
402 402 * Performs the common portion of an IDS operation.
403 403 *
404 404 */
405 405
406 406 #include <sys/types.h>
407 407 #include <sys/param.h>
408 408 #include <sys/cred.h>
409 409 #include <sys/policy.h>
410 410 #include <sys/proc.h>
411 411 #include <sys/user.h>
412 412 #include <sys/ipc.h>
413 413 #include <sys/ipc_impl.h>
414 414 #include <sys/errno.h>
415 415 #include <sys/systm.h>
416 416 #include <sys/list.h>
417 417 #include <sys/atomic.h>
418 418 #include <sys/zone.h>
419 419 #include <sys/task.h>
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420 420 #include <sys/modctl.h>
421 421
422 422 #include <c2/audit.h>
423 423
424 424 static struct modlmisc modlmisc = {
425 425 &mod_miscops,
426 426 "common ipc code",
427 427 };
428 428
429 429 static struct modlinkage modlinkage = {
430 - MODREV_1, (void *)&modlmisc, NULL
430 + MODREV_1, { (void *)&modlmisc, NULL }
431 431 };
432 432
433 433
434 434 int
435 435 _init(void)
436 436 {
437 437 return (mod_install(&modlinkage));
438 438 }
439 439
440 440 int
441 441 _fini(void)
442 442 {
443 443 return (mod_remove(&modlinkage));
444 444 }
445 445
446 446 int
447 447 _info(struct modinfo *modinfop)
448 448 {
449 449 return (mod_info(&modlinkage, modinfop));
450 450 }
451 451
452 452
453 453 /*
454 454 * Check message, semaphore, or shared memory access permissions.
455 455 *
456 456 * This routine verifies the requested access permission for the current
457 457 * process. The zone ids are compared, and the appropriate bits are
458 458 * checked corresponding to owner, group (including the list of
459 459 * supplementary groups), or everyone. Zero is returned on success.
460 460 * On failure, the security policy is asked to check to override the
461 461 * permissions check; the policy will either return 0 for access granted
462 462 * or EACCES.
463 463 *
464 464 * Access to objects in other zones requires that the caller be in the
465 465 * global zone and have the appropriate IPC_DAC_* privilege, regardless
466 466 * of whether the uid or gid match those of the object. Note that
467 467 * cross-zone accesses will normally never get here since they'll
468 468 * fail in ipc_lookup or ipc_get.
469 469 *
470 470 * The arguments must be set up as follows:
471 471 * p - Pointer to permission structure to verify
472 472 * mode - Desired access permissions
473 473 */
474 474 int
475 475 ipcperm_access(kipc_perm_t *p, int mode, cred_t *cr)
476 476 {
477 477 int shifts = 0;
478 478 uid_t uid = crgetuid(cr);
479 479 zoneid_t zoneid = getzoneid();
480 480
481 481 if (p->ipc_zoneid == zoneid) {
482 482 if (uid != p->ipc_uid && uid != p->ipc_cuid) {
483 483 shifts += 3;
484 484 if (!groupmember(p->ipc_gid, cr) &&
485 485 !groupmember(p->ipc_cgid, cr))
486 486 shifts += 3;
487 487 }
488 488
489 489 mode &= ~(p->ipc_mode << shifts);
490 490
491 491 if (mode == 0)
492 492 return (0);
493 493 } else if (zoneid != GLOBAL_ZONEID)
494 494 return (EACCES);
495 495
496 496 return (secpolicy_ipc_access(cr, p, mode));
497 497 }
498 498
499 499 /*
500 500 * There are two versions of the ipcperm_set/stat functions:
501 501 * ipcperm_??? - for use with IPC_SET/STAT
502 502 * ipcperm_???_64 - for use with IPC_SET64/STAT64
503 503 *
504 504 * These functions encapsulate the common portions (copying, permission
505 505 * checks, and auditing) of the set/stat operations. All, except for
506 506 * stat and stat_64 which are void, return 0 on success or a non-zero
507 507 * errno value on error.
508 508 */
509 509
510 510 int
511 511 ipcperm_set(ipc_service_t *service, struct cred *cr,
512 512 kipc_perm_t *kperm, struct ipc_perm *perm, model_t model)
513 513 {
514 514 STRUCT_HANDLE(ipc_perm, lperm);
515 515 uid_t uid;
516 516 gid_t gid;
517 517 mode_t mode;
518 518 zone_t *zone;
519 519
520 520 ASSERT(IPC_LOCKED(service, kperm));
521 521
522 522 STRUCT_SET_HANDLE(lperm, model, perm);
523 523 uid = STRUCT_FGET(lperm, uid);
524 524 gid = STRUCT_FGET(lperm, gid);
525 525 mode = STRUCT_FGET(lperm, mode);
526 526
527 527 if (secpolicy_ipc_owner(cr, kperm) != 0)
528 528 return (EPERM);
529 529
530 530 zone = crgetzone(cr);
531 531 if (!VALID_UID(uid, zone) || !VALID_GID(gid, zone))
532 532 return (EINVAL);
533 533
534 534 kperm->ipc_uid = uid;
535 535 kperm->ipc_gid = gid;
536 536 kperm->ipc_mode = (mode & 0777) | (kperm->ipc_mode & ~0777);
537 537
538 538 if (AU_AUDITING())
539 539 audit_ipcget(service->ipcs_atype, kperm);
540 540
541 541 return (0);
542 542 }
543 543
544 544 void
545 545 ipcperm_stat(struct ipc_perm *perm, kipc_perm_t *kperm, model_t model)
546 546 {
547 547 STRUCT_HANDLE(ipc_perm, lperm);
548 548
549 549 STRUCT_SET_HANDLE(lperm, model, perm);
550 550 STRUCT_FSET(lperm, uid, kperm->ipc_uid);
551 551 STRUCT_FSET(lperm, gid, kperm->ipc_gid);
552 552 STRUCT_FSET(lperm, cuid, kperm->ipc_cuid);
553 553 STRUCT_FSET(lperm, cgid, kperm->ipc_cgid);
554 554 STRUCT_FSET(lperm, mode, kperm->ipc_mode);
555 555 STRUCT_FSET(lperm, seq, 0);
556 556 STRUCT_FSET(lperm, key, kperm->ipc_key);
557 557 }
558 558
559 559 int
560 560 ipcperm_set64(ipc_service_t *service, struct cred *cr,
561 561 kipc_perm_t *kperm, ipc_perm64_t *perm64)
562 562 {
563 563 zone_t *zone;
564 564
565 565 ASSERT(IPC_LOCKED(service, kperm));
566 566
567 567 if (secpolicy_ipc_owner(cr, kperm) != 0)
568 568 return (EPERM);
569 569
570 570 zone = crgetzone(cr);
571 571 if (!VALID_UID(perm64->ipcx_uid, zone) ||
572 572 !VALID_GID(perm64->ipcx_gid, zone))
573 573 return (EINVAL);
574 574
575 575 kperm->ipc_uid = perm64->ipcx_uid;
576 576 kperm->ipc_gid = perm64->ipcx_gid;
577 577 kperm->ipc_mode = (perm64->ipcx_mode & 0777) |
578 578 (kperm->ipc_mode & ~0777);
579 579
580 580 if (AU_AUDITING())
581 581 audit_ipcget(service->ipcs_atype, kperm);
582 582
583 583 return (0);
584 584 }
585 585
586 586 void
587 587 ipcperm_stat64(ipc_perm64_t *perm64, kipc_perm_t *kperm)
588 588 {
589 589 perm64->ipcx_uid = kperm->ipc_uid;
590 590 perm64->ipcx_gid = kperm->ipc_gid;
591 591 perm64->ipcx_cuid = kperm->ipc_cuid;
592 592 perm64->ipcx_cgid = kperm->ipc_cgid;
593 593 perm64->ipcx_mode = kperm->ipc_mode;
594 594 perm64->ipcx_key = kperm->ipc_key;
595 595 perm64->ipcx_projid = kperm->ipc_proj->kpj_id;
596 596 perm64->ipcx_zoneid = kperm->ipc_zoneid;
597 597 }
598 598
599 599
600 600 /*
601 601 * ipc key comparator.
602 602 */
603 603 static int
604 604 ipc_key_compar(const void *a, const void *b)
605 605 {
606 606 kipc_perm_t *aperm = (kipc_perm_t *)a;
607 607 kipc_perm_t *bperm = (kipc_perm_t *)b;
608 608 int ak = aperm->ipc_key;
609 609 int bk = bperm->ipc_key;
610 610 zoneid_t az;
611 611 zoneid_t bz;
612 612
613 613 ASSERT(ak != IPC_PRIVATE);
614 614 ASSERT(bk != IPC_PRIVATE);
615 615
616 616 /*
617 617 * Compare key first, then zoneid. This optimizes performance for
618 618 * systems with only one zone, since the zone checks will only be
619 619 * made when the keys match.
620 620 */
621 621 if (ak < bk)
622 622 return (-1);
623 623 if (ak > bk)
624 624 return (1);
625 625
626 626 /* keys match */
627 627 az = aperm->ipc_zoneid;
628 628 bz = bperm->ipc_zoneid;
629 629 if (az < bz)
630 630 return (-1);
631 631 if (az > bz)
632 632 return (1);
633 633 return (0);
634 634 }
635 635
636 636 /*
637 637 * Create an ipc service.
638 638 */
639 639 ipc_service_t *
640 640 ipcs_create(const char *name, rctl_hndl_t proj_rctl, rctl_hndl_t zone_rctl,
641 641 size_t size, ipc_func_t *dtor, ipc_func_t *rmid, int audit_type,
642 642 size_t rctl_offset)
643 643 {
644 644 ipc_service_t *result;
645 645
646 646 result = kmem_alloc(sizeof (ipc_service_t), KM_SLEEP);
647 647
648 648 mutex_init(&result->ipcs_lock, NULL, MUTEX_ADAPTIVE, NULL);
649 649 result->ipcs_count = 0;
650 650 avl_create(&result->ipcs_keys, ipc_key_compar, size, 0);
651 651 result->ipcs_tabsz = IPC_IDS_MIN;
652 652 result->ipcs_table =
653 653 kmem_zalloc(IPC_IDS_MIN * sizeof (ipc_slot_t), KM_SLEEP);
654 654 result->ipcs_ssize = size;
655 655 result->ipcs_ids = id_space_create(name, 0, IPC_IDS_MIN);
656 656 result->ipcs_dtor = dtor;
657 657 result->ipcs_rmid = rmid;
658 658 result->ipcs_proj_rctl = proj_rctl;
659 659 result->ipcs_zone_rctl = zone_rctl;
660 660 result->ipcs_atype = audit_type;
661 661 ASSERT(rctl_offset < sizeof (ipc_rqty_t));
662 662 result->ipcs_rctlofs = rctl_offset;
663 663 list_create(&result->ipcs_usedids, sizeof (kipc_perm_t),
664 664 offsetof(kipc_perm_t, ipc_list));
665 665
666 666 return (result);
667 667 }
668 668
669 669 /*
670 670 * Destroy an ipc service.
671 671 */
672 672 void
673 673 ipcs_destroy(ipc_service_t *service)
674 674 {
675 675 ipc_slot_t *slot, *next;
676 676
677 677 mutex_enter(&service->ipcs_lock);
678 678
679 679 ASSERT(service->ipcs_count == 0);
680 680 avl_destroy(&service->ipcs_keys);
681 681 list_destroy(&service->ipcs_usedids);
682 682 id_space_destroy(service->ipcs_ids);
683 683
684 684 for (slot = service->ipcs_table; slot; slot = next) {
685 685 next = slot[0].ipct_chain;
686 686 kmem_free(slot, service->ipcs_tabsz * sizeof (ipc_slot_t));
687 687 service->ipcs_tabsz >>= 1;
688 688 }
689 689
690 690 mutex_destroy(&service->ipcs_lock);
691 691 kmem_free(service, sizeof (ipc_service_t));
692 692 }
693 693
694 694 /*
695 695 * Takes the service lock.
696 696 */
697 697 void
698 698 ipcs_lock(ipc_service_t *service)
699 699 {
700 700 mutex_enter(&service->ipcs_lock);
701 701 }
702 702
703 703 /*
704 704 * Releases the service lock.
705 705 */
706 706 void
707 707 ipcs_unlock(ipc_service_t *service)
708 708 {
709 709 mutex_exit(&service->ipcs_lock);
710 710 }
711 711
712 712
713 713 /*
714 714 * Locks the specified ID. Returns the ID's ID table index.
715 715 */
716 716 static int
717 717 ipc_lock_internal(ipc_service_t *service, uint_t id)
718 718 {
719 719 uint_t tabsz;
720 720 uint_t index;
721 721 kmutex_t *mutex;
722 722
723 723 for (;;) {
724 724 tabsz = service->ipcs_tabsz;
725 725 membar_consumer();
726 726 index = id & (tabsz - 1);
727 727 mutex = &service->ipcs_table[index].ipct_lock;
728 728 mutex_enter(mutex);
729 729 if (tabsz == service->ipcs_tabsz)
730 730 break;
731 731 mutex_exit(mutex);
732 732 }
733 733
734 734 return (index);
735 735 }
736 736
737 737 /*
738 738 * Locks the specified ID. Returns a pointer to the ID's lock.
739 739 */
740 740 kmutex_t *
741 741 ipc_lock(ipc_service_t *service, int id)
742 742 {
743 743 uint_t index;
744 744
745 745 /*
746 746 * These assertions don't reflect requirements of the code
747 747 * which follows, but they should never fail nonetheless.
748 748 */
749 749 ASSERT(id >= 0);
750 750 ASSERT(IPC_INDEX(id) < service->ipcs_tabsz);
751 751 index = ipc_lock_internal(service, id);
752 752
753 753 return (&service->ipcs_table[index].ipct_lock);
754 754 }
755 755
756 756 /*
757 757 * Checks to see if the held lock provided is the current lock for the
758 758 * specified id. If so, we return it instead of dropping it and
759 759 * returning the result of ipc_lock. This is intended to speed up cv
760 760 * wakeups where we are left holding a lock which could be stale, but
761 761 * probably isn't.
762 762 */
763 763 kmutex_t *
764 764 ipc_relock(ipc_service_t *service, int id, kmutex_t *lock)
765 765 {
766 766 ASSERT(id >= 0);
767 767 ASSERT(IPC_INDEX(id) < service->ipcs_tabsz);
768 768 ASSERT(MUTEX_HELD(lock));
769 769
770 770 if (&service->ipcs_table[IPC_INDEX(id)].ipct_lock == lock)
771 771 return (lock);
772 772
773 773 mutex_exit(lock);
774 774 return (ipc_lock(service, id));
775 775 }
776 776
777 777 /*
778 778 * Performs an ID lookup. If the ID doesn't exist or has been removed,
779 779 * or isn't visible to the caller (because of zones), NULL is returned.
780 780 * Otherwise, a pointer to the ID's perm structure and held ID lock are
781 781 * returned.
782 782 */
783 783 kmutex_t *
784 784 ipc_lookup(ipc_service_t *service, int id, kipc_perm_t **perm)
785 785 {
786 786 kipc_perm_t *result;
787 787 uint_t index;
788 788
789 789 /*
790 790 * There is no need to check to see if id is in-range (i.e.
791 791 * positive and fits into the table). If it is out-of-range,
792 792 * the id simply won't match the object's.
793 793 */
794 794
795 795 index = ipc_lock_internal(service, id);
796 796 result = service->ipcs_table[index].ipct_data;
797 797 if (result == NULL || result->ipc_id != (uint_t)id ||
798 798 !HASZONEACCESS(curproc, result->ipc_zoneid)) {
799 799 mutex_exit(&service->ipcs_table[index].ipct_lock);
800 800 return (NULL);
801 801 }
802 802
803 803 ASSERT(IPC_SEQ(id) == service->ipcs_table[index].ipct_seq);
804 804
805 805 *perm = result;
806 806 if (AU_AUDITING())
807 807 audit_ipc(service->ipcs_atype, id, result);
808 808
809 809 return (&service->ipcs_table[index].ipct_lock);
810 810 }
811 811
812 812 /*
813 813 * Increase the reference count on an ID.
814 814 */
815 815 /*ARGSUSED*/
816 816 void
817 817 ipc_hold(ipc_service_t *s, kipc_perm_t *perm)
818 818 {
819 819 ASSERT(IPC_INDEX(perm->ipc_id) < s->ipcs_tabsz);
820 820 ASSERT(IPC_LOCKED(s, perm));
821 821 perm->ipc_ref++;
822 822 }
823 823
824 824 /*
825 825 * Decrease the reference count on an ID and drops the ID's lock.
826 826 * Destroys the ID if the new reference count is zero.
827 827 */
828 828 void
829 829 ipc_rele(ipc_service_t *s, kipc_perm_t *perm)
830 830 {
831 831 int nref;
832 832
833 833 ASSERT(IPC_INDEX(perm->ipc_id) < s->ipcs_tabsz);
834 834 ASSERT(IPC_LOCKED(s, perm));
835 835 ASSERT(perm->ipc_ref > 0);
836 836
837 837 nref = --perm->ipc_ref;
838 838 mutex_exit(&s->ipcs_table[IPC_INDEX(perm->ipc_id)].ipct_lock);
839 839
840 840 if (nref == 0) {
841 841 ASSERT(IPC_FREE(perm)); /* ipc_rmid clears IPC_ALLOC */
842 842 s->ipcs_dtor(perm);
843 843 project_rele(perm->ipc_proj);
844 844 zone_rele_ref(&perm->ipc_zone_ref, ZONE_REF_IPC);
845 845 kmem_free(perm, s->ipcs_ssize);
846 846 }
847 847 }
848 848
849 849 /*
850 850 * Decrease the reference count on an ID, but don't drop the ID lock.
851 851 * Used in cases where one thread needs to remove many references (on
852 852 * behalf of other parties).
853 853 */
854 854 void
855 855 ipc_rele_locked(ipc_service_t *s, kipc_perm_t *perm)
856 856 {
857 857 ASSERT(perm->ipc_ref > 1);
858 858 ASSERT(IPC_INDEX(perm->ipc_id) < s->ipcs_tabsz);
859 859 ASSERT(IPC_LOCKED(s, perm));
860 860
861 861 perm->ipc_ref--;
862 862 }
863 863
864 864
865 865 /*
866 866 * Internal function to grow the service ID table.
867 867 */
868 868 static int
869 869 ipc_grow(ipc_service_t *service)
870 870 {
871 871 ipc_slot_t *new, *old;
872 872 int i, oldsize, newsize;
873 873
874 874 ASSERT(MUTEX_HELD(&service->ipcs_lock));
875 875 ASSERT(MUTEX_NOT_HELD(&curproc->p_lock));
876 876
877 877 if (service->ipcs_tabsz == IPC_IDS_MAX)
878 878 return (ENOSPC);
879 879
880 880 oldsize = service->ipcs_tabsz;
881 881 newsize = oldsize << 1;
882 882 new = kmem_zalloc(newsize * sizeof (ipc_slot_t), KM_NOSLEEP);
883 883 if (new == NULL)
884 884 return (ENOSPC);
885 885
886 886 old = service->ipcs_table;
887 887 for (i = 0; i < oldsize; i++) {
888 888 mutex_enter(&old[i].ipct_lock);
889 889 mutex_enter(&new[i].ipct_lock);
890 890
891 891 new[i].ipct_seq = old[i].ipct_seq;
892 892 new[i].ipct_data = old[i].ipct_data;
893 893 old[i].ipct_data = NULL;
894 894 }
895 895
896 896 new[0].ipct_chain = old;
897 897 service->ipcs_table = new;
898 898 membar_producer();
899 899 service->ipcs_tabsz = newsize;
900 900
901 901 for (i = 0; i < oldsize; i++) {
902 902 mutex_exit(&old[i].ipct_lock);
903 903 mutex_exit(&new[i].ipct_lock);
904 904 }
905 905
906 906 id_space_extend(service->ipcs_ids, oldsize, service->ipcs_tabsz);
907 907
908 908 return (0);
909 909 }
910 910
911 911
912 912 static int
913 913 ipc_keylookup(ipc_service_t *service, key_t key, int flag, kipc_perm_t **permp)
914 914 {
915 915 kipc_perm_t *perm = NULL;
916 916 avl_index_t where;
917 917 kipc_perm_t template;
918 918
919 919 ASSERT(MUTEX_HELD(&service->ipcs_lock));
920 920
921 921 template.ipc_key = key;
922 922 template.ipc_zoneid = getzoneid();
923 923 if (perm = avl_find(&service->ipcs_keys, &template, &where)) {
924 924 ASSERT(!IPC_FREE(perm));
925 925 if ((flag & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
926 926 return (EEXIST);
927 927 if ((flag & 0777) & ~perm->ipc_mode) {
928 928 if (AU_AUDITING())
929 929 audit_ipcget(NULL, (void *)perm);
930 930 return (EACCES);
931 931 }
932 932 *permp = perm;
933 933 return (0);
934 934 } else if (flag & IPC_CREAT) {
935 935 *permp = NULL;
936 936 return (0);
937 937 }
938 938 return (ENOENT);
939 939 }
940 940
941 941 static int
942 942 ipc_alloc_test(ipc_service_t *service, proc_t *pp)
943 943 {
944 944 ASSERT(MUTEX_HELD(&service->ipcs_lock));
945 945
946 946 /*
947 947 * Resizing the table first would result in a cleaner code
948 948 * path, but would also allow a user to (permanently) double
949 949 * the id table size in cases where the allocation would be
950 950 * denied. Hence we test the rctl first.
951 951 */
952 952 retry:
953 953 mutex_enter(&pp->p_lock);
954 954 if ((rctl_test(service->ipcs_proj_rctl, pp->p_task->tk_proj->kpj_rctls,
955 955 pp, 1, RCA_SAFE) & RCT_DENY) ||
956 956 (rctl_test(service->ipcs_zone_rctl, pp->p_zone->zone_rctls,
957 957 pp, 1, RCA_SAFE) & RCT_DENY)) {
958 958 mutex_exit(&pp->p_lock);
959 959 return (ENOSPC);
960 960 }
961 961
962 962 if (service->ipcs_count == service->ipcs_tabsz) {
963 963 int error;
964 964
965 965 mutex_exit(&pp->p_lock);
966 966 if (error = ipc_grow(service))
967 967 return (error);
968 968 goto retry;
969 969 }
970 970
971 971 return (0);
972 972 }
973 973
974 974 /*
975 975 * Given a key, search for or create the associated identifier.
976 976 *
977 977 * If IPC_CREAT is specified and the key isn't found, or if the key is
978 978 * equal to IPC_PRIVATE, we return 0 and place a pointer to a newly
979 979 * allocated object structure in permp. A pointer to the held service
980 980 * lock is placed in lockp. ipc_mode's IPC_ALLOC bit is clear.
981 981 *
982 982 * If the key is found and no error conditions arise, we return 0 and
983 983 * place a pointer to the existing object structure in permp. A
984 984 * pointer to the held ID lock is placed in lockp. ipc_mode's
985 985 * IPC_ALLOC bit is set.
986 986 *
987 987 * Otherwise, a non-zero errno value is returned.
988 988 */
989 989 int
990 990 ipc_get(ipc_service_t *service, key_t key, int flag, kipc_perm_t **permp,
991 991 kmutex_t **lockp)
992 992 {
993 993 kipc_perm_t *perm = NULL;
994 994 proc_t *pp = curproc;
995 995 int error, index;
996 996 cred_t *cr = CRED();
997 997
998 998 if (key != IPC_PRIVATE) {
999 999
1000 1000 mutex_enter(&service->ipcs_lock);
1001 1001 error = ipc_keylookup(service, key, flag, &perm);
1002 1002 if (perm != NULL)
1003 1003 index = ipc_lock_internal(service, perm->ipc_id);
1004 1004 mutex_exit(&service->ipcs_lock);
1005 1005
1006 1006 if (error) {
1007 1007 ASSERT(perm == NULL);
1008 1008 return (error);
1009 1009 }
1010 1010
1011 1011 if (perm) {
1012 1012 ASSERT(!IPC_FREE(perm));
1013 1013 *permp = perm;
1014 1014 *lockp = &service->ipcs_table[index].ipct_lock;
1015 1015 return (0);
1016 1016 }
1017 1017
1018 1018 /* Key not found; fall through */
1019 1019 }
1020 1020
1021 1021 perm = kmem_zalloc(service->ipcs_ssize, KM_SLEEP);
1022 1022
1023 1023 mutex_enter(&service->ipcs_lock);
1024 1024 if (error = ipc_alloc_test(service, pp)) {
1025 1025 mutex_exit(&service->ipcs_lock);
1026 1026 kmem_free(perm, service->ipcs_ssize);
1027 1027 return (error);
1028 1028 }
1029 1029
1030 1030 perm->ipc_cuid = perm->ipc_uid = crgetuid(cr);
1031 1031 perm->ipc_cgid = perm->ipc_gid = crgetgid(cr);
1032 1032 perm->ipc_zoneid = getzoneid();
1033 1033 perm->ipc_mode = flag & 0777;
1034 1034 perm->ipc_key = key;
1035 1035 perm->ipc_ref = 1;
1036 1036 perm->ipc_id = IPC_ID_INVAL;
1037 1037 *permp = perm;
1038 1038 *lockp = &service->ipcs_lock;
1039 1039
1040 1040 return (0);
1041 1041 }
1042 1042
1043 1043 /*
1044 1044 * Attempts to add the a newly created ID to the global namespace. If
1045 1045 * creating it would cause an error, we return the error. If there is
1046 1046 * the possibility that we could obtain the existing ID and return it
1047 1047 * to the user, we return EAGAIN. Otherwise, we return 0 with p_lock
1048 1048 * and the service lock held.
1049 1049 *
1050 1050 * Since this should be only called after all initialization has been
1051 1051 * completed, on failure we automatically invoke the destructor for the
1052 1052 * object and deallocate the memory associated with it.
1053 1053 */
1054 1054 int
1055 1055 ipc_commit_begin(ipc_service_t *service, key_t key, int flag,
1056 1056 kipc_perm_t *newperm)
1057 1057 {
1058 1058 kipc_perm_t *perm;
1059 1059 int error;
1060 1060 proc_t *pp = curproc;
1061 1061
1062 1062 ASSERT(newperm->ipc_ref == 1);
1063 1063 ASSERT(IPC_FREE(newperm));
1064 1064
1065 1065 /*
1066 1066 * Set ipc_proj and ipc_zone_ref so that future calls to ipc_cleanup()
1067 1067 * clean up the necessary state. This must be done before the
1068 1068 * potential call to ipcs_dtor() below.
1069 1069 */
1070 1070 newperm->ipc_proj = pp->p_task->tk_proj;
1071 1071 zone_init_ref(&newperm->ipc_zone_ref);
1072 1072 zone_hold_ref(pp->p_zone, &newperm->ipc_zone_ref, ZONE_REF_IPC);
1073 1073
1074 1074 mutex_enter(&service->ipcs_lock);
1075 1075 /*
1076 1076 * Ensure that no-one has raced with us and created the key.
1077 1077 */
1078 1078 if ((key != IPC_PRIVATE) &&
1079 1079 (((error = ipc_keylookup(service, key, flag, &perm)) != 0) ||
1080 1080 (perm != NULL))) {
1081 1081 error = error ? error : EAGAIN;
1082 1082 goto errout;
1083 1083 }
1084 1084
1085 1085 /*
1086 1086 * Ensure that no-one has raced with us and used the last of
1087 1087 * the permissible ids, or the last of the free spaces in the
1088 1088 * id table.
1089 1089 */
1090 1090 if (error = ipc_alloc_test(service, pp))
1091 1091 goto errout;
1092 1092
1093 1093 ASSERT(MUTEX_HELD(&service->ipcs_lock));
1094 1094 ASSERT(MUTEX_HELD(&pp->p_lock));
1095 1095
1096 1096 return (0);
1097 1097 errout:
1098 1098 mutex_exit(&service->ipcs_lock);
1099 1099 service->ipcs_dtor(newperm);
1100 1100 zone_rele_ref(&newperm->ipc_zone_ref, ZONE_REF_IPC);
1101 1101 kmem_free(newperm, service->ipcs_ssize);
1102 1102 return (error);
1103 1103 }
1104 1104
1105 1105 /*
1106 1106 * Commit the ID allocation transaction. Called with p_lock and the
1107 1107 * service lock held, both of which are dropped. Returns the held ID
1108 1108 * lock so the caller can extract the ID and perform ipcget auditing.
1109 1109 */
1110 1110 kmutex_t *
1111 1111 ipc_commit_end(ipc_service_t *service, kipc_perm_t *perm)
1112 1112 {
1113 1113 ipc_slot_t *slot;
1114 1114 avl_index_t where;
1115 1115 int index;
1116 1116 void *loc;
1117 1117
1118 1118 ASSERT(MUTEX_HELD(&service->ipcs_lock));
1119 1119 ASSERT(MUTEX_HELD(&curproc->p_lock));
1120 1120
1121 1121 (void) project_hold(perm->ipc_proj);
1122 1122 mutex_exit(&curproc->p_lock);
1123 1123
1124 1124 /*
1125 1125 * Pick out our slot.
1126 1126 */
1127 1127 service->ipcs_count++;
1128 1128 index = id_alloc(service->ipcs_ids);
1129 1129 ASSERT(index < service->ipcs_tabsz);
1130 1130 slot = &service->ipcs_table[index];
1131 1131 mutex_enter(&slot->ipct_lock);
1132 1132 ASSERT(slot->ipct_data == NULL);
1133 1133
1134 1134 /*
1135 1135 * Update the perm structure.
1136 1136 */
1137 1137 perm->ipc_mode |= IPC_ALLOC;
1138 1138 perm->ipc_id = (slot->ipct_seq << IPC_SEQ_SHIFT) | index;
1139 1139
1140 1140 /*
1141 1141 * Push into global visibility.
1142 1142 */
1143 1143 slot->ipct_data = perm;
1144 1144 if (perm->ipc_key != IPC_PRIVATE) {
1145 1145 loc = avl_find(&service->ipcs_keys, perm, &where);
1146 1146 ASSERT(loc == NULL);
1147 1147 avl_insert(&service->ipcs_keys, perm, where);
1148 1148 }
1149 1149 list_insert_head(&service->ipcs_usedids, perm);
1150 1150
1151 1151 /*
1152 1152 * Update resource consumption.
1153 1153 */
1154 1154 IPC_PROJ_USAGE(perm, service) += 1;
1155 1155 IPC_ZONE_USAGE(perm, service) += 1;
1156 1156
1157 1157 mutex_exit(&service->ipcs_lock);
1158 1158 return (&slot->ipct_lock);
1159 1159 }
1160 1160
1161 1161 /*
1162 1162 * Clean up function, in case the allocation fails. If called between
1163 1163 * ipc_lookup and ipc_commit_begin, perm->ipc_proj will be 0 and we
1164 1164 * merely free the perm structure. If called after ipc_commit_begin,
1165 1165 * we also drop locks and call the ID's destructor.
1166 1166 */
1167 1167 void
1168 1168 ipc_cleanup(ipc_service_t *service, kipc_perm_t *perm)
1169 1169 {
1170 1170 ASSERT(IPC_FREE(perm));
1171 1171 if (perm->ipc_proj) {
1172 1172 mutex_exit(&curproc->p_lock);
1173 1173 mutex_exit(&service->ipcs_lock);
1174 1174 service->ipcs_dtor(perm);
1175 1175 }
1176 1176 if (perm->ipc_zone_ref.zref_zone != NULL)
1177 1177 zone_rele_ref(&perm->ipc_zone_ref, ZONE_REF_IPC);
1178 1178 kmem_free(perm, service->ipcs_ssize);
1179 1179 }
1180 1180
1181 1181
1182 1182 /*
1183 1183 * Common code to remove an IPC object. This should be called after
1184 1184 * all permissions checks have been performed, and with the service
1185 1185 * and ID locked. Note that this does not remove the object from
1186 1186 * the ipcs_usedids list (this needs to be done by the caller before
1187 1187 * dropping the service lock).
1188 1188 */
1189 1189 static void
1190 1190 ipc_remove(ipc_service_t *service, kipc_perm_t *perm)
1191 1191 {
1192 1192 int id = perm->ipc_id;
1193 1193 int index;
1194 1194
1195 1195 ASSERT(MUTEX_HELD(&service->ipcs_lock));
1196 1196 ASSERT(IPC_LOCKED(service, perm));
1197 1197
1198 1198 index = IPC_INDEX(id);
1199 1199
1200 1200 service->ipcs_table[index].ipct_data = NULL;
1201 1201
1202 1202 if (perm->ipc_key != IPC_PRIVATE)
1203 1203 avl_remove(&service->ipcs_keys, perm);
1204 1204 list_remove(&service->ipcs_usedids, perm);
1205 1205 perm->ipc_mode &= ~IPC_ALLOC;
1206 1206
1207 1207 id_free(service->ipcs_ids, index);
1208 1208
1209 1209 if (service->ipcs_table[index].ipct_seq++ == IPC_SEQ_MASK)
1210 1210 service->ipcs_table[index].ipct_seq = 0;
1211 1211 service->ipcs_count--;
1212 1212 ASSERT(IPC_PROJ_USAGE(perm, service) > 0);
1213 1213 ASSERT(IPC_ZONE_USAGE(perm, service) > 0);
1214 1214 IPC_PROJ_USAGE(perm, service) -= 1;
1215 1215 IPC_ZONE_USAGE(perm, service) -= 1;
1216 1216 ASSERT(service->ipcs_count || ((IPC_PROJ_USAGE(perm, service) == 0) &&
1217 1217 (IPC_ZONE_USAGE(perm, service) == 0)));
1218 1218 }
1219 1219
1220 1220
1221 1221 /*
1222 1222 * Common code to perform an IPC_RMID. Returns an errno value on
1223 1223 * failure, 0 on success.
1224 1224 */
1225 1225 int
1226 1226 ipc_rmid(ipc_service_t *service, int id, cred_t *cr)
1227 1227 {
1228 1228 kipc_perm_t *perm;
1229 1229 kmutex_t *lock;
1230 1230
1231 1231 mutex_enter(&service->ipcs_lock);
1232 1232
1233 1233 lock = ipc_lookup(service, id, &perm);
1234 1234 if (lock == NULL) {
1235 1235 mutex_exit(&service->ipcs_lock);
1236 1236 return (EINVAL);
1237 1237 }
1238 1238
1239 1239 ASSERT(service->ipcs_count > 0);
1240 1240
1241 1241 if (secpolicy_ipc_owner(cr, perm) != 0) {
1242 1242 mutex_exit(lock);
1243 1243 mutex_exit(&service->ipcs_lock);
1244 1244 return (EPERM);
1245 1245 }
1246 1246
1247 1247 /*
1248 1248 * Nothing can fail from this point on.
1249 1249 */
1250 1250 ipc_remove(service, perm);
1251 1251 mutex_exit(&service->ipcs_lock);
1252 1252
1253 1253 /* perform any per-service removal actions */
1254 1254 service->ipcs_rmid(perm);
1255 1255
1256 1256 ipc_rele(service, perm);
1257 1257
1258 1258 return (0);
1259 1259 }
1260 1260
1261 1261 /*
1262 1262 * Implementation for shmids, semids, and msgids. buf is the address
1263 1263 * of the user buffer, nids is the size, and pnids is a pointer to
1264 1264 * where we write the actual number of ids that [would] have been
1265 1265 * copied out.
1266 1266 */
1267 1267 int
1268 1268 ipc_ids(ipc_service_t *service, int *buf, uint_t nids, uint_t *pnids)
1269 1269 {
1270 1270 kipc_perm_t *perm;
1271 1271 size_t idsize = 0;
1272 1272 int error = 0;
1273 1273 int idcount;
1274 1274 int *ids;
1275 1275 int numids = 0;
1276 1276 zoneid_t zoneid = getzoneid();
1277 1277 int global = INGLOBALZONE(curproc);
1278 1278
1279 1279 if (buf == NULL)
1280 1280 nids = 0;
1281 1281
1282 1282 /*
1283 1283 * Get an accurate count of the total number of ids, and allocate a
1284 1284 * staging buffer. Since ipcs_count is always sane, we don't have
1285 1285 * to take ipcs_lock for our first guess. If there are no ids, or
1286 1286 * we're in the global zone and the number of ids is greater than
1287 1287 * the size of the specified buffer, we shunt to the end. Otherwise,
1288 1288 * we go through the id list looking for (and counting) what is
1289 1289 * visible in the specified zone.
1290 1290 */
1291 1291 idcount = service->ipcs_count;
1292 1292 for (;;) {
1293 1293 if ((global && idcount > nids) || idcount == 0) {
1294 1294 numids = idcount;
1295 1295 nids = 0;
1296 1296 goto out;
1297 1297 }
1298 1298
1299 1299 idsize = idcount * sizeof (int);
1300 1300 ids = kmem_alloc(idsize, KM_SLEEP);
1301 1301
1302 1302 mutex_enter(&service->ipcs_lock);
1303 1303 if (idcount >= service->ipcs_count)
1304 1304 break;
1305 1305 idcount = service->ipcs_count;
1306 1306 mutex_exit(&service->ipcs_lock);
1307 1307
1308 1308 if (idsize != 0) {
1309 1309 kmem_free(ids, idsize);
1310 1310 idsize = 0;
1311 1311 }
1312 1312 }
1313 1313
1314 1314 for (perm = list_head(&service->ipcs_usedids); perm != NULL;
1315 1315 perm = list_next(&service->ipcs_usedids, perm)) {
1316 1316 ASSERT(!IPC_FREE(perm));
1317 1317 if (global || perm->ipc_zoneid == zoneid)
1318 1318 ids[numids++] = perm->ipc_id;
1319 1319 }
1320 1320 mutex_exit(&service->ipcs_lock);
1321 1321
1322 1322 /*
1323 1323 * If there isn't enough space to hold all of the ids, just
1324 1324 * return the number of ids without copying out any of them.
1325 1325 */
1326 1326 if (nids < numids)
1327 1327 nids = 0;
1328 1328
1329 1329 out:
1330 1330 if (suword32(pnids, (uint32_t)numids) ||
1331 1331 (nids != 0 && copyout(ids, buf, numids * sizeof (int))))
1332 1332 error = EFAULT;
1333 1333 if (idsize != 0)
1334 1334 kmem_free(ids, idsize);
1335 1335 return (error);
1336 1336 }
1337 1337
1338 1338 /*
1339 1339 * Destroy IPC objects from the given service that are associated with
1340 1340 * the given zone.
1341 1341 *
1342 1342 * We can't hold on to the service lock when freeing objects, so we
1343 1343 * first search the service and move all the objects to a private
1344 1344 * list, then walk through and free them after dropping the lock.
1345 1345 */
1346 1346 void
1347 1347 ipc_remove_zone(ipc_service_t *service, zoneid_t zoneid)
1348 1348 {
1349 1349 kipc_perm_t *perm, *next;
1350 1350 list_t rmlist;
1351 1351 kmutex_t *lock;
1352 1352
1353 1353 list_create(&rmlist, sizeof (kipc_perm_t),
1354 1354 offsetof(kipc_perm_t, ipc_list));
1355 1355
1356 1356 mutex_enter(&service->ipcs_lock);
1357 1357 for (perm = list_head(&service->ipcs_usedids); perm != NULL;
1358 1358 perm = next) {
1359 1359 next = list_next(&service->ipcs_usedids, perm);
1360 1360 if (perm->ipc_zoneid != zoneid)
1361 1361 continue;
1362 1362
1363 1363 /*
1364 1364 * Remove the object from the service, then put it on
1365 1365 * the removal list so we can defer the call to
1366 1366 * ipc_rele (which will actually free the structure).
1367 1367 * We need to do this since the destructor may grab
1368 1368 * the service lock.
1369 1369 */
1370 1370 ASSERT(!IPC_FREE(perm));
1371 1371 lock = ipc_lock(service, perm->ipc_id);
1372 1372 ipc_remove(service, perm);
1373 1373 mutex_exit(lock);
1374 1374 list_insert_tail(&rmlist, perm);
1375 1375 }
1376 1376 mutex_exit(&service->ipcs_lock);
1377 1377
1378 1378 /*
1379 1379 * Now that we've dropped the service lock, loop through the
1380 1380 * private list freeing removed objects.
1381 1381 */
1382 1382 for (perm = list_head(&rmlist); perm != NULL; perm = next) {
1383 1383 next = list_next(&rmlist, perm);
1384 1384 list_remove(&rmlist, perm);
1385 1385
1386 1386 (void) ipc_lock(service, perm->ipc_id);
1387 1387
1388 1388 /* perform any per-service removal actions */
1389 1389 service->ipcs_rmid(perm);
1390 1390
1391 1391 /* release reference */
1392 1392 ipc_rele(service, perm);
1393 1393 }
1394 1394
1395 1395 list_destroy(&rmlist);
1396 1396 }
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