1/*
2 * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28/*
29 * Copyright (c) 1990, 1996-1998 Apple Computer, Inc.
30 * All Rights Reserved.
31 */
32/*
33 * posix_sem.c : Support for POSIX semaphore APIs
34 *
35 * File: posix_sem.c
36 * Author: Ananthakrishna Ramesh
37 *
38 * HISTORY
39 * 2-Sep-1999 A.Ramesh
40 * Created for MacOSX
41 *
42 */
43/*
44 * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
45 * support for mandatory and extensible security protections. This notice
46 * is included in support of clause 2.2 (b) of the Apple Public License,
47 * Version 2.0.
48 */
49
50#include <sys/cdefs.h>
51#include <sys/param.h>
52#include <sys/systm.h>
53#include <sys/kernel.h>
54#include <sys/file_internal.h>
55#include <sys/filedesc.h>
56#include <sys/stat.h>
57#include <sys/proc_internal.h>
58#include <sys/kauth.h>
59#include <sys/mount.h>
60#include <sys/namei.h>
61#include <sys/vnode.h>
62#include <sys/ioctl.h>
63#include <sys/tty.h>
64#include <sys/malloc.h>
65#include <sys/semaphore.h>
66#include <sys/sysproto.h>
67#include <sys/proc_info.h>
68
69#if CONFIG_MACF
70#include <sys/vnode_internal.h>
71#include <security/mac_framework.h>
72#endif
73
74#include <security/audit/audit.h>
75
76#include <mach/mach_types.h>
77#include <mach/vm_prot.h>
78#include <mach/semaphore.h>
79#include <mach/sync_policy.h>
80#include <mach/task.h>
81#include <kern/kern_types.h>
82#include <kern/task.h>
83#include <kern/clock.h>
84#include <mach/kern_return.h>
85
86#define f_flag fp_glob->fg_flag
87#define f_ops fp_glob->fg_ops
88
89#define PSEMNAMLEN 31 /* maximum name segment length we bother with */
90
91struct pseminfo {
92 unsigned int psem_flags;
93 unsigned int psem_usecount;
94 mode_t psem_mode;
95 uid_t psem_uid;
96 gid_t psem_gid;
97 char psem_name[PSEMNAMLEN + 1]; /* segment name */
98 semaphore_t psem_semobject;
99 struct label * psem_label;
100 pid_t psem_creator_pid;
101 uint64_t psem_creator_uniqueid;
102};
103#define PSEMINFO_NULL (struct pseminfo *)0
104
105#define PSEM_NONE 1
106#define PSEM_DEFINED 2
107#define PSEM_ALLOCATED 4
108#define PSEM_MAPPED 8
109#define PSEM_INUSE 0x10
110#define PSEM_REMOVED 0x20
111#define PSEM_INCREATE 0x40
112#define PSEM_INDELETE 0x80
113
114struct psemcache {
115 LIST_ENTRY(psemcache) psem_hash; /* hash chain */
116 struct pseminfo *pseminfo; /* vnode the name refers to */
117 size_t psem_nlen; /* length of name */
118 char psem_name[PSEMNAMLEN + 1]; /* segment name */
119};
120#define PSEMCACHE_NULL (struct psemcache *)0
121
122#define PSEMCACHE_NOTFOUND (0)
123#define PSEMCACHE_FOUND (-1)
124#define PSEMCACHE_NEGATIVE (ENOENT)
125
126struct psemstats {
127 long goodhits; /* hits that we can really use */
128 long neghits; /* negative hits that we can use */
129 long badhits; /* hits we must drop */
130 long falsehits; /* hits with id mismatch */
131 long miss; /* misses */
132 long longnames; /* long names that ignore cache */
133};
134
135struct psemname {
136 char *psem_nameptr; /* pointer to looked up name */
137 size_t psem_namelen; /* length of looked up component */
138 u_int32_t psem_hash; /* hash value of looked up name */
139};
140
141struct psemnode {
142 struct pseminfo *pinfo;
143#if DIAGNOSTIC
144 unsigned int readcnt;
145 unsigned int writecnt;
146#endif
147};
148#define PSEMNODE_NULL (struct psemnode *)0
149
150
151#define PSEMHASH(pnp) \
152 (&psemhashtbl[(pnp)->psem_hash & psemhash])
153LIST_HEAD(psemhashhead, psemcache) * psemhashtbl; /* Hash Table */
154u_long psemhash; /* size of hash table - 1 */
155long psemnument; /* number of cache entries allocated */
156long posix_sem_max = 10000; /* tunable for max POSIX semaphores */
157 /* 10000 limits to ~1M of memory */
158SYSCTL_NODE(_kern, KERN_POSIX, posix, CTLFLAG_RW | CTLFLAG_LOCKED, 0, "Posix");
159SYSCTL_NODE(_kern_posix, OID_AUTO, sem, CTLFLAG_RW | CTLFLAG_LOCKED, 0, "Semaphores");
160SYSCTL_LONG(_kern_posix_sem, OID_AUTO, max, CTLFLAG_RW | CTLFLAG_LOCKED, &posix_sem_max, "max");
161
162struct psemstats psemstats; /* cache effectiveness statistics */
163
164static int psem_access(struct pseminfo *pinfo, mode_t mode, kauth_cred_t cred);
165static int psem_cache_search(struct pseminfo **,
166 struct psemname *, struct psemcache **);
167static int psem_delete(struct pseminfo * pinfo);
168
169static int psem_closefile(struct fileglob *fp, vfs_context_t ctx);
170static int psem_unlink_internal(struct pseminfo *pinfo, struct psemcache *pcache);
171
172static const struct fileops psemops = {
173 .fo_type = DTYPE_PSXSEM,
174 .fo_read = fo_no_read,
175 .fo_write = fo_no_write,
176 .fo_ioctl = fo_no_ioctl,
177 .fo_select = fo_no_select,
178 .fo_close = psem_closefile,
179 .fo_drain = fo_no_drain,
180 .fo_kqfilter = fo_no_kqfilter,
181};
182
183static LCK_GRP_DECLARE(psx_sem_subsys_lck_grp, "posix semaphores");
184static LCK_MTX_DECLARE(psx_sem_subsys_mutex, &psx_sem_subsys_lck_grp);
185
186#define PSEM_SUBSYS_LOCK() lck_mtx_lock(&psx_sem_subsys_mutex)
187#define PSEM_SUBSYS_UNLOCK() lck_mtx_unlock(&psx_sem_subsys_mutex)
188#define PSEM_SUBSYS_ASSERT_HELD() LCK_MTX_ASSERT(&psx_sem_subsys_mutex, LCK_MTX_ASSERT_OWNED)
189
190
191static int psem_cache_add(struct pseminfo *psemp, struct psemname *pnp, struct psemcache *pcp);
192static void psem_cache_delete(struct psemcache *pcp);
193int psem_cache_purge_all(void);
194
195/*
196 * Lookup an entry in the cache
197 *
198 *
199 * status of -1 is returned if matches
200 * If the lookup determines that the name does not exist
201 * (negative cacheing), a status of ENOENT is returned. If the lookup
202 * fails, a status of zero is returned.
203 */
204
205static int
206psem_cache_search(struct pseminfo **psemp, struct psemname *pnp,
207 struct psemcache **pcache)
208{
209 struct psemcache *pcp, *nnp;
210 struct psemhashhead *pcpp;
211
212 if (pnp->psem_namelen > PSEMNAMLEN) {
213 psemstats.longnames++;
214 return PSEMCACHE_NOTFOUND;
215 }
216
217 pcpp = PSEMHASH(pnp);
218 for (pcp = pcpp->lh_first; pcp != 0; pcp = nnp) {
219 nnp = pcp->psem_hash.le_next;
220 if (pcp->psem_nlen == pnp->psem_namelen &&
221 !bcmp(s1: pcp->psem_name, s2: pnp->psem_nameptr, n: pcp->psem_nlen)) {
222 break;
223 }
224 }
225
226 if (pcp == 0) {
227 psemstats.miss++;
228 return PSEMCACHE_NOTFOUND;
229 }
230
231 /* We found a "positive" match, return the vnode */
232 if (pcp->pseminfo) {
233 psemstats.goodhits++;
234 /* TOUCH(ncp); */
235 *psemp = pcp->pseminfo;
236 *pcache = pcp;
237 return PSEMCACHE_FOUND;
238 }
239
240 /*
241 * We found a "negative" match, ENOENT notifies client of this match.
242 * The nc_vpid field records whether this is a whiteout.
243 */
244 psemstats.neghits++;
245 return PSEMCACHE_NEGATIVE;
246}
247
248/*
249 * Add an entry to the cache.
250 */
251static int
252psem_cache_add(struct pseminfo *psemp, struct psemname *pnp, struct psemcache *pcp)
253{
254 struct psemhashhead *pcpp;
255 struct pseminfo *dpinfo;
256 struct psemcache *dpcp;
257
258#if DIAGNOSTIC
259 if (pnp->psem_namelen > PSEMNAMLEN) {
260 panic("cache_enter: name too long");
261 }
262#endif
263
264
265 /* if the entry has already been added by some one else return */
266 if (psem_cache_search(psemp: &dpinfo, pnp, pcache: &dpcp) == PSEMCACHE_FOUND) {
267 return EEXIST;
268 }
269 if (psemnument >= posix_sem_max) {
270 return ENOSPC;
271 }
272 psemnument++;
273 /*
274 * Fill in cache info, if vp is NULL this is a "negative" cache entry.
275 * For negative entries, we have to record whether it is a whiteout.
276 * the whiteout flag is stored in the nc_vpid field which is
277 * otherwise unused.
278 */
279 pcp->pseminfo = psemp;
280 pcp->psem_nlen = pnp->psem_namelen;
281 bcopy(src: pnp->psem_nameptr, dst: pcp->psem_name, n: pcp->psem_nlen);
282 pcpp = PSEMHASH(pnp);
283#if DIAGNOSTIC
284 {
285 struct psemcache *p;
286
287 for (p = pcpp->lh_first; p != 0; p = p->psem_hash.le_next) {
288 if (p == pcp) {
289 panic("psem:cache_enter duplicate");
290 }
291 }
292 }
293#endif
294 LIST_INSERT_HEAD(pcpp, pcp, psem_hash);
295 return 0;
296}
297
298/*
299 * Name cache initialization, from vfs_init() when we are booting
300 */
301void
302psem_cache_init(void)
303{
304 psemhashtbl = hashinit(count: (int)(posix_sem_max / 2), M_SHM, hashmask: &psemhash);
305}
306
307static void
308psem_cache_delete(struct psemcache *pcp)
309{
310#if DIAGNOSTIC
311 if (pcp->psem_hash.le_prev == 0) {
312 panic("psem namecache purge le_prev");
313 }
314 if (pcp->psem_hash.le_next == pcp) {
315 panic("namecache purge le_next");
316 }
317#endif /* DIAGNOSTIC */
318 LIST_REMOVE(pcp, psem_hash);
319 pcp->psem_hash.le_prev = NULL;
320 psemnument--;
321}
322
323/*
324 * Remove all cached psem entries. Open semaphores (with a positive refcount)
325 * will continue to exist, but their cache entries tying them to a particular
326 * name/path will be removed making all future lookups on the name fail.
327 */
328int
329psem_cache_purge_all(void)
330{
331 struct psemcache *pcp, *tmppcp;
332 struct psemhashhead *pcpp;
333 int error = 0;
334
335 if (kauth_cred_issuser(cred: kauth_cred_get()) == 0) {
336 return EPERM;
337 }
338
339 PSEM_SUBSYS_LOCK();
340 for (pcpp = &psemhashtbl[psemhash]; pcpp >= psemhashtbl; pcpp--) {
341 LIST_FOREACH_SAFE(pcp, pcpp, psem_hash, tmppcp) {
342 assert(pcp->psem_nlen);
343 /*
344 * unconditionally unlink the cache entry
345 */
346 error = psem_unlink_internal(pinfo: pcp->pseminfo, pcache: pcp);
347 if (error) {
348 goto out;
349 }
350 }
351 }
352 assert(psemnument == 0);
353
354out:
355 PSEM_SUBSYS_UNLOCK();
356
357 if (error) {
358 printf("%s: Error %d removing all semaphores: %ld remain!\n",
359 __func__, error, psemnument);
360 }
361 return error;
362}
363
364/*
365 * In order to support unnamed POSIX semaphores, the named
366 * POSIX semaphores will have to move out of the per-process
367 * open filetable, and into a global table that is shared with
368 * unnamed POSIX semaphores, since unnamed POSIX semaphores
369 * are typically used by declaring instances in shared memory,
370 * and there's no other way to do this without changing the
371 * underlying type, which would introduce binary compatibility
372 * issues.
373 */
374int
375sem_open(proc_t p, struct sem_open_args *uap, user_addr_t *retval)
376{
377 size_t i;
378 int indx, error;
379 struct psemname nd;
380 struct pseminfo *pinfo;
381 struct fileproc *fp = NULL;
382 char *pnbuf = NULL;
383 struct pseminfo *new_pinfo = PSEMINFO_NULL;
384 struct psemnode *new_pnode = PSEMNODE_NULL;
385 struct psemcache *pcache = PSEMCACHE_NULL;
386 char * nameptr;
387 char * cp;
388 size_t pathlen, plen;
389 mode_t fmode;
390 mode_t cmode = (mode_t)uap->mode;
391 int value = uap->value;
392 int incache = 0;
393 struct psemcache *pcp = PSEMCACHE_NULL;
394 kern_return_t kret = KERN_INVALID_ADDRESS; /* default fail */
395
396 AUDIT_ARG(fflags, uap->oflag);
397 AUDIT_ARG(mode, (mode_t)uap->mode);
398 AUDIT_ARG(value32, uap->value);
399
400 pinfo = PSEMINFO_NULL;
401
402 /*
403 * Preallocate everything we might need up front to avoid taking
404 * and dropping the lock, opening us up to race conditions.
405 */
406 pnbuf = zalloc_flags(ZV_NAMEI, Z_WAITOK | Z_ZERO);
407
408 pathlen = MAXPATHLEN;
409 error = copyinstr(uaddr: uap->name, kaddr: pnbuf, MAXPATHLEN, done: &pathlen);
410 if (error) {
411 goto bad;
412 }
413 AUDIT_ARG(text, pnbuf);
414 if ((pathlen > PSEMNAMLEN)) {
415 error = ENAMETOOLONG;
416 goto bad;
417 }
418
419#ifdef PSXSEM_NAME_RESTRICT
420 nameptr = pnbuf;
421 if (*nameptr == '/') {
422 while (*(nameptr++) == '/') {
423 plen--;
424 error = EINVAL;
425 goto bad;
426 }
427 } else {
428 error = EINVAL;
429 goto bad;
430 }
431#endif /* PSXSEM_NAME_RESTRICT */
432
433 plen = pathlen;
434 nameptr = pnbuf;
435 nd.psem_nameptr = nameptr;
436 nd.psem_namelen = plen;
437 nd.psem_hash = 0;
438
439 for (cp = nameptr, i = 1; *cp != 0 && i <= plen; i++, cp++) {
440 nd.psem_hash += (unsigned char)*cp * i;
441 }
442
443 /*
444 * attempt to allocate a new fp; if unsuccessful, the fp will be
445 * left unmodified (NULL).
446 */
447 error = falloc(p, &fp, &indx);
448 if (error) {
449 goto bad;
450 }
451
452 /*
453 * We allocate a new entry if we are less than the maximum
454 * allowed and the one at the front of the LRU list is in use.
455 * Otherwise we use the one at the front of the LRU list.
456 */
457 pcp = kalloc_type(struct psemcache, Z_WAITOK | Z_ZERO | Z_NOFAIL);
458 new_pinfo = kalloc_type(struct pseminfo, Z_WAITOK | Z_ZERO | Z_NOFAIL);
459#if CONFIG_MACF
460 mac_posixsem_label_init(psem: new_pinfo);
461#endif
462
463 /*
464 * Provisionally create the semaphore in the new_pinfo; we have to do
465 * this here to prevent locking later. We use the value of kret to
466 * signal success or failure, which is why we set its default value
467 * to KERN_INVALID_ADDRESS, above.
468 */
469
470 fmode = (mode_t)FFLAGS(uap->oflag);
471
472 if ((fmode & O_CREAT)) {
473 if ((value < 0) || (value > SEM_VALUE_MAX)) {
474 error = EINVAL;
475 goto bad;
476 }
477
478 kret = semaphore_create(task: kernel_task, semaphore: &new_pinfo->psem_semobject, SYNC_POLICY_FIFO, value);
479
480 if (kret != KERN_SUCCESS) {
481 switch (kret) {
482 case KERN_RESOURCE_SHORTAGE:
483 error = ENOMEM;
484 break;
485 case KERN_PROTECTION_FAILURE:
486 error = EACCES;
487 break;
488 default:
489 error = EINVAL;
490 }
491 goto bad;
492 }
493 }
494
495 new_pnode = kalloc_type(struct psemnode, Z_WAITOK | Z_ZERO | Z_NOFAIL);
496
497 PSEM_SUBSYS_LOCK();
498 error = psem_cache_search(psemp: &pinfo, pnp: &nd, pcache: &pcache);
499
500 if (error == PSEMCACHE_NEGATIVE) {
501 error = EINVAL;
502 goto bad_locked;
503 }
504
505 if (error == PSEMCACHE_FOUND) {
506 incache = 1;
507 } else {
508 incache = 0;
509 }
510
511 cmode &= ALLPERMS;
512
513 if (((fmode & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL)) && incache) {
514 /* sem exists and opened O_EXCL */
515#if notyet
516 if (pinfo->psem_flags & PSEM_INDELETE) {
517 }
518#endif
519 AUDIT_ARG(posix_ipc_perm, pinfo->psem_uid,
520 pinfo->psem_gid, pinfo->psem_mode);
521 error = EEXIST;
522 goto bad_locked;
523 }
524 if (((fmode & (O_CREAT | O_EXCL)) == O_CREAT) && incache) {
525 /* As per POSIX, O_CREAT has no effect */
526 fmode &= ~O_CREAT;
527 }
528
529 if ((fmode & O_CREAT)) {
530 /* create a new one (commit the allocation) */
531 pinfo = new_pinfo;
532 pinfo->psem_flags = PSEM_DEFINED | PSEM_INCREATE;
533 pinfo->psem_usecount = 1;
534 pinfo->psem_mode = cmode;
535 pinfo->psem_uid = kauth_getuid();
536 pinfo->psem_gid = kauth_getgid();
537 bcopy(src: pnbuf, dst: &pinfo->psem_name[0], PSEMNAMLEN);
538 pinfo->psem_name[PSEMNAMLEN] = 0;
539 pinfo->psem_flags &= ~PSEM_DEFINED;
540 pinfo->psem_flags |= PSEM_ALLOCATED;
541 pinfo->psem_creator_pid = proc_getpid(p);
542 pinfo->psem_creator_uniqueid = proc_uniqueid(p);
543
544#if CONFIG_MACF
545 error = mac_posixsem_check_create(cred: kauth_cred_get(), name: nameptr);
546 if (error) {
547 goto bad_locked;
548 }
549 mac_posixsem_label_associate(cred: kauth_cred_get(), psem: pinfo, name: nameptr);
550#endif
551 } else {
552 /* semaphore should exist as it is without O_CREAT */
553 if (!incache) {
554 error = ENOENT;
555 goto bad_locked;
556 }
557 if (pinfo->psem_flags & PSEM_INDELETE) {
558 error = ENOENT;
559 goto bad_locked;
560 }
561 AUDIT_ARG(posix_ipc_perm, pinfo->psem_uid,
562 pinfo->psem_gid, pinfo->psem_mode);
563#if CONFIG_MACF
564 error = mac_posixsem_check_open(cred: kauth_cred_get(), psem: pinfo);
565 if (error) {
566 goto bad_locked;
567 }
568#endif
569 if ((error = psem_access(pinfo, mode: fmode, cred: kauth_cred_get()))) {
570 goto bad_locked;
571 }
572 }
573
574 if (!incache) {
575 /* if successful, this will consume the pcp */
576 if ((error = psem_cache_add(psemp: pinfo, pnp: &nd, pcp))) {
577 goto bad_locked;
578 }
579 }
580 pinfo->psem_flags &= ~PSEM_INCREATE;
581 pinfo->psem_usecount++;
582 new_pnode->pinfo = pinfo;
583 PSEM_SUBSYS_UNLOCK();
584
585 /*
586 * if incache, we did not use the new pcp or the new pcp or the
587 * new . and we must free them.
588 */
589 if (incache) {
590 kfree_type(struct psemcache, pcp);
591 pcp = PSEMCACHE_NULL;
592 if (new_pinfo != PSEMINFO_NULL) {
593 /* return value ignored - we can't _not_ do this */
594 (void)semaphore_destroy(task: kernel_task, semaphore: new_pinfo->psem_semobject);
595#if CONFIG_MACF
596 mac_posixsem_label_destroy(psem: new_pinfo);
597#endif
598 kfree_type(struct pseminfo, new_pinfo);
599 new_pinfo = PSEMINFO_NULL;
600 }
601 }
602
603 proc_fdlock(p);
604 fp->f_flag = fmode & FMASK;
605 fp->f_ops = &psemops;
606 fp_set_data(fp, fg_data: new_pnode);
607 procfdtbl_releasefd(p, fd: indx, NULL);
608 fp_drop(p, fd: indx, fp, locked: 1);
609 proc_fdunlock(p);
610
611 *retval = CAST_USER_ADDR_T(indx);
612 zfree(ZV_NAMEI, pnbuf);
613 return 0;
614
615bad_locked:
616 PSEM_SUBSYS_UNLOCK();
617bad:
618 kfree_type(struct psemcache, pcp);
619
620 kfree_type(struct psemnode, new_pnode);
621
622 if (fp != NULL) {
623 fp_free(p, fd: indx, fp);
624 }
625
626 if (new_pinfo != PSEMINFO_NULL) {
627 /*
628 * kret signals whether or not we successfully created a
629 * Mach semaphore for this semaphore; if so, we need to
630 * destroy it here.
631 */
632 if (kret == KERN_SUCCESS) {
633 /* return value ignored - we can't _not_ do this */
634 (void)semaphore_destroy(task: kernel_task, semaphore: new_pinfo->psem_semobject);
635 }
636#if CONFIG_MACF
637 mac_posixsem_label_destroy(psem: new_pinfo);
638#endif
639 kfree_type(struct pseminfo, new_pinfo);
640 }
641
642 if (pnbuf != NULL) {
643 zfree(ZV_NAMEI, pnbuf);
644 }
645 return error;
646}
647
648/*
649 * XXX This code is repeated in several places
650 */
651static int
652psem_access(struct pseminfo *pinfo, mode_t mode, kauth_cred_t cred)
653{
654 mode_t mode_req = ((mode & FREAD) ? S_IRUSR : 0) |
655 ((mode & FWRITE) ? S_IWUSR : 0);
656
657 /* Otherwise, user id 0 always gets access. */
658 if (!suser(cred, NULL)) {
659 return 0;
660 }
661
662 return posix_cred_access(cred, object_uid: pinfo->psem_uid, object_gid: pinfo->psem_gid, object_mode: pinfo->psem_mode, mode_req);
663}
664
665static int
666psem_unlink_internal(struct pseminfo *pinfo, struct psemcache *pcache)
667{
668 PSEM_SUBSYS_ASSERT_HELD();
669
670 if (!pinfo || !pcache) {
671 return EINVAL;
672 }
673
674 if ((pinfo->psem_flags & (PSEM_DEFINED | PSEM_ALLOCATED)) == 0) {
675 return EINVAL;
676 }
677
678 if (pinfo->psem_flags & PSEM_INDELETE) {
679 return 0;
680 }
681
682 AUDIT_ARG(posix_ipc_perm, pinfo->psem_uid, pinfo->psem_gid,
683 pinfo->psem_mode);
684
685 pinfo->psem_flags |= PSEM_INDELETE;
686 pinfo->psem_usecount--;
687
688 if (!pinfo->psem_usecount) {
689 psem_delete(pinfo);
690 kfree_type(struct pseminfo, pinfo);
691 } else {
692 pinfo->psem_flags |= PSEM_REMOVED;
693 }
694
695 psem_cache_delete(pcp: pcache);
696 kfree_type(struct psemcache, pcache);
697 return 0;
698}
699
700
701int
702sem_unlink(__unused proc_t p, struct sem_unlink_args *uap, __unused int32_t *retval)
703{
704 size_t i;
705 int error = 0;
706 struct psemname nd;
707 struct pseminfo *pinfo;
708 char * nameptr;
709 char * cp;
710 char * pnbuf;
711 size_t pathlen;
712 struct psemcache *pcache = PSEMCACHE_NULL;
713
714 pinfo = PSEMINFO_NULL;
715
716 pnbuf = zalloc(view: ZV_NAMEI);
717
718 pathlen = MAXPATHLEN;
719 error = copyinstr(uaddr: uap->name, kaddr: pnbuf, MAXPATHLEN, done: &pathlen);
720 if (error) {
721 goto bad;
722 }
723 AUDIT_ARG(text, pnbuf);
724 if (pathlen > PSEMNAMLEN) {
725 error = ENAMETOOLONG;
726 goto bad;
727 }
728
729 nameptr = pnbuf;
730
731#ifdef PSXSEM_NAME_RESTRICT
732 if (*nameptr == '/') {
733 while (*(nameptr++) == '/') {
734 pathlen--;
735 error = EINVAL;
736 goto bad;
737 }
738 } else {
739 error = EINVAL;
740 goto bad;
741 }
742#endif /* PSXSEM_NAME_RESTRICT */
743
744 nd.psem_nameptr = nameptr;
745 nd.psem_namelen = pathlen;
746 nd.psem_hash = 0;
747
748 for (cp = nameptr, i = 1; *cp != 0 && i <= pathlen; i++, cp++) {
749 nd.psem_hash += (unsigned char)*cp * i;
750 }
751
752 PSEM_SUBSYS_LOCK();
753 error = psem_cache_search(psemp: &pinfo, pnp: &nd, pcache: &pcache);
754
755 if (error != PSEMCACHE_FOUND) {
756 PSEM_SUBSYS_UNLOCK();
757 error = ENOENT;
758 goto bad;
759 }
760
761#if CONFIG_MACF
762 error = mac_posixsem_check_unlink(cred: kauth_cred_get(), psem: pinfo, name: nameptr);
763 if (error) {
764 PSEM_SUBSYS_UNLOCK();
765 goto bad;
766 }
767#endif
768 if ((error = psem_access(pinfo, mode: pinfo->psem_mode, cred: kauth_cred_get()))) {
769 PSEM_SUBSYS_UNLOCK();
770 goto bad;
771 }
772
773 error = psem_unlink_internal(pinfo, pcache);
774 PSEM_SUBSYS_UNLOCK();
775
776bad:
777 zfree(ZV_NAMEI, pnbuf);
778 return error;
779}
780
781int
782sem_close(proc_t p, struct sem_close_args *uap, __unused int32_t *retval)
783{
784 int fd = CAST_DOWN_EXPLICIT(int, uap->sem);
785 kauth_cred_t p_cred;
786 struct fileproc *fp;
787
788 AUDIT_ARG(fd, fd); /* XXX This seems wrong; uap->sem is a pointer */
789
790 proc_fdlock(p);
791 if ((fp = fp_get_noref_locked(p, fd)) == NULL) {
792 proc_fdunlock(p);
793 return EBADF;
794 }
795 if (FILEGLOB_DTYPE(fp->fp_glob) != DTYPE_PSXSEM) {
796 proc_fdunlock(p);
797 return EBADF;
798 }
799
800 p_cred = current_cached_proc_cred(p);
801 return fp_close_and_unlock(p, p_cred, fd, fp, flags: 0);
802}
803
804int
805sem_wait(proc_t p, struct sem_wait_args *uap, int32_t *retval)
806{
807 __pthread_testcancel(presyscall: 1);
808 return sem_wait_nocancel(p, (struct sem_wait_nocancel_args *)uap, retval);
809}
810
811int
812sem_wait_nocancel(proc_t p, struct sem_wait_nocancel_args *uap, __unused int32_t *retval)
813{
814 int fd = CAST_DOWN_EXPLICIT(int, uap->sem);
815 struct fileproc *fp;
816 struct pseminfo * pinfo;
817 struct psemnode * pnode;
818 kern_return_t kret;
819 int error;
820
821 error = fp_get_ftype(p, fd, ftype: DTYPE_PSXSEM, EBADF, fpp: &fp);
822 if (error) {
823 return error;
824 }
825 pnode = (struct psemnode *)fp_get_data(fp);
826
827 PSEM_SUBSYS_LOCK();
828 if ((pinfo = pnode->pinfo) == PSEMINFO_NULL) {
829 PSEM_SUBSYS_UNLOCK();
830 error = EINVAL;
831 goto out;
832 }
833 if ((pinfo->psem_flags & (PSEM_DEFINED | PSEM_ALLOCATED))
834 != PSEM_ALLOCATED) {
835 PSEM_SUBSYS_UNLOCK();
836 error = EINVAL;
837 goto out;
838 }
839#if CONFIG_MACF
840 error = mac_posixsem_check_wait(cred: kauth_cred_get(), psem: pinfo);
841 if (error) {
842 PSEM_SUBSYS_UNLOCK();
843 goto out;
844 }
845#endif
846 PSEM_SUBSYS_UNLOCK();
847 kret = semaphore_wait(semaphore: pinfo->psem_semobject);
848 switch (kret) {
849 case KERN_INVALID_ADDRESS:
850 case KERN_PROTECTION_FAILURE:
851 error = EACCES;
852 break;
853 case KERN_ABORTED:
854 case KERN_OPERATION_TIMED_OUT:
855 error = EINTR;
856 break;
857 case KERN_SUCCESS:
858 error = 0;
859 break;
860 default:
861 error = EINVAL;
862 break;
863 }
864out:
865 fp_drop(p, fd, fp, locked: 0);
866 return error;
867}
868
869int
870sem_trywait(proc_t p, struct sem_trywait_args *uap, __unused int32_t *retval)
871{
872 int fd = CAST_DOWN_EXPLICIT(int, uap->sem);
873 struct fileproc *fp;
874 struct pseminfo * pinfo;
875 struct psemnode * pnode;
876 kern_return_t kret;
877 mach_timespec_t wait_time;
878 int error;
879
880 error = fp_get_ftype(p, fd, ftype: DTYPE_PSXSEM, EBADF, fpp: &fp);
881 if (error) {
882 return error;
883 }
884 pnode = (struct psemnode *)fp_get_data(fp);
885
886 PSEM_SUBSYS_LOCK();
887 if ((pinfo = pnode->pinfo) == PSEMINFO_NULL) {
888 PSEM_SUBSYS_UNLOCK();
889 error = EINVAL;
890 goto out;
891 }
892 if ((pinfo->psem_flags & (PSEM_DEFINED | PSEM_ALLOCATED))
893 != PSEM_ALLOCATED) {
894 PSEM_SUBSYS_UNLOCK();
895 error = EINVAL;
896 goto out;
897 }
898#if CONFIG_MACF
899 error = mac_posixsem_check_wait(cred: kauth_cred_get(), psem: pinfo);
900 if (error) {
901 PSEM_SUBSYS_UNLOCK();
902 goto out;
903 }
904#endif
905 PSEM_SUBSYS_UNLOCK();
906 wait_time.tv_sec = 0;
907 wait_time.tv_nsec = 0;
908
909 kret = semaphore_timedwait(semaphore: pinfo->psem_semobject, MACH_TIMESPEC_ZERO);
910 switch (kret) {
911 case KERN_INVALID_ADDRESS:
912 case KERN_PROTECTION_FAILURE:
913 error = EINVAL;
914 break;
915 case KERN_ABORTED:
916 error = EINTR;
917 break;
918 case KERN_OPERATION_TIMED_OUT:
919 error = EAGAIN;
920 break;
921 case KERN_SUCCESS:
922 error = 0;
923 break;
924 default:
925 error = EINVAL;
926 break;
927 }
928out:
929 fp_drop(p, fd, fp, locked: 0);
930 return error;
931}
932
933int
934sem_post(proc_t p, struct sem_post_args *uap, __unused int32_t *retval)
935{
936 int fd = CAST_DOWN_EXPLICIT(int, uap->sem);
937 struct fileproc *fp;
938 struct pseminfo * pinfo;
939 struct psemnode * pnode;
940 kern_return_t kret;
941 int error;
942
943 error = fp_get_ftype(p, fd, ftype: DTYPE_PSXSEM, EBADF, fpp: &fp);
944 if (error) {
945 return error;
946 }
947 pnode = (struct psemnode *)fp_get_data(fp);
948
949 PSEM_SUBSYS_LOCK();
950 if ((pinfo = pnode->pinfo) == PSEMINFO_NULL) {
951 PSEM_SUBSYS_UNLOCK();
952 error = EINVAL;
953 goto out;
954 }
955 if ((pinfo->psem_flags & (PSEM_DEFINED | PSEM_ALLOCATED))
956 != PSEM_ALLOCATED) {
957 PSEM_SUBSYS_UNLOCK();
958 error = EINVAL;
959 goto out;
960 }
961#if CONFIG_MACF
962 error = mac_posixsem_check_post(cred: kauth_cred_get(), psem: pinfo);
963 if (error) {
964 PSEM_SUBSYS_UNLOCK();
965 goto out;
966 }
967#endif
968 PSEM_SUBSYS_UNLOCK();
969 kret = semaphore_signal(semaphore: pinfo->psem_semobject);
970 switch (kret) {
971 case KERN_INVALID_ADDRESS:
972 case KERN_PROTECTION_FAILURE:
973 error = EINVAL;
974 break;
975 case KERN_ABORTED:
976 case KERN_OPERATION_TIMED_OUT:
977 error = EINTR;
978 break;
979 case KERN_SUCCESS:
980 error = 0;
981 break;
982 default:
983 error = EINVAL;
984 break;
985 }
986out:
987 fp_drop(p, fd, fp, locked: 0);
988 return error;
989}
990
991static int
992psem_close(struct psemnode *pnode)
993{
994 int error = 0;
995 struct pseminfo *pinfo;
996
997 PSEM_SUBSYS_LOCK();
998 if ((pinfo = pnode->pinfo) == PSEMINFO_NULL) {
999 PSEM_SUBSYS_UNLOCK();
1000 return EINVAL;
1001 }
1002
1003 if ((pinfo->psem_flags & PSEM_ALLOCATED) != PSEM_ALLOCATED) {
1004 PSEM_SUBSYS_UNLOCK();
1005 return EINVAL;
1006 }
1007#if DIAGNOSTIC
1008 if (!pinfo->psem_usecount) {
1009 kprintf("negative usecount in psem_close\n");
1010 }
1011#endif /* DIAGNOSTIC */
1012 pinfo->psem_usecount--;
1013
1014 if ((pinfo->psem_flags & PSEM_REMOVED) && !pinfo->psem_usecount) {
1015 PSEM_SUBSYS_UNLOCK();
1016 /* lock dropped as only semaphore is destroyed here */
1017 error = psem_delete(pinfo);
1018 kfree_type(struct pseminfo, pinfo);
1019 } else {
1020 PSEM_SUBSYS_UNLOCK();
1021 }
1022 /* subsystem lock is dropped when we get here */
1023 kfree_type(struct psemnode, pnode);
1024 return error;
1025}
1026
1027static int
1028psem_closefile(struct fileglob *fg, __unused vfs_context_t ctx)
1029{
1030 /*
1031 * Not locked as psem_close is called only from here and is locked
1032 * properly
1033 */
1034 return psem_close(pnode: (struct psemnode *)fg_get_data(fg));
1035}
1036
1037static int
1038psem_delete(struct pseminfo * pinfo)
1039{
1040 kern_return_t kret;
1041
1042 kret = semaphore_destroy(task: kernel_task, semaphore: pinfo->psem_semobject);
1043#if CONFIG_MACF
1044 mac_posixsem_label_destroy(psem: pinfo);
1045#endif
1046
1047 switch (kret) {
1048 case KERN_INVALID_ADDRESS:
1049 case KERN_PROTECTION_FAILURE:
1050 return EINVAL;
1051 case KERN_ABORTED:
1052 case KERN_OPERATION_TIMED_OUT:
1053 return EINTR;
1054 case KERN_SUCCESS:
1055 return 0;
1056 default:
1057 return EINVAL;
1058 }
1059}
1060
1061int
1062fill_pseminfo(struct psemnode *pnode, struct psem_info * info)
1063{
1064 struct pseminfo *pinfo;
1065 struct vinfo_stat *sb;
1066
1067 PSEM_SUBSYS_LOCK();
1068 if ((pinfo = pnode->pinfo) == PSEMINFO_NULL) {
1069 PSEM_SUBSYS_UNLOCK();
1070 return EINVAL;
1071 }
1072
1073#if 0
1074 if ((pinfo->psem_flags & PSEM_ALLOCATED) != PSEM_ALLOCATED) {
1075 PSEM_SUBSYS_UNLOCK();
1076 return EINVAL;
1077 }
1078#endif
1079
1080 sb = &info->psem_stat;
1081 bzero(s: sb, n: sizeof(struct vinfo_stat));
1082
1083 sb->vst_mode = pinfo->psem_mode;
1084 sb->vst_uid = pinfo->psem_uid;
1085 sb->vst_gid = pinfo->psem_gid;
1086 sb->vst_size = pinfo->psem_usecount;
1087 bcopy(src: &pinfo->psem_name[0], dst: &info->psem_name[0], PSEMNAMLEN + 1);
1088
1089 PSEM_SUBSYS_UNLOCK();
1090 return 0;
1091}
1092
1093#if CONFIG_MACF
1094void
1095psem_label_associate(struct fileproc *fp, struct vnode *vp, vfs_context_t ctx)
1096{
1097 struct psemnode *pnode;
1098 struct pseminfo *psem;
1099
1100 PSEM_SUBSYS_LOCK();
1101 pnode = (struct psemnode *)fp_get_data(fp);
1102 if (pnode != NULL) {
1103 psem = pnode->pinfo;
1104 if (psem != NULL) {
1105 mac_posixsem_vnode_label_associate(
1106 cred: vfs_context_ucred(ctx), psem,
1107 plabel: mac_posixsem_label(psem),
1108 vp, vlabel: mac_vnode_label(vp));
1109 }
1110 }
1111 PSEM_SUBSYS_UNLOCK();
1112}
1113#endif
1114