FreeBSD/Linux Kernel Cross Reference
sys/kern/sysv_shm.c
1 /* $NetBSD: sysv_shm.c,v 1.82.10.1 2005/09/18 20:09:50 tron Exp $ */
2
3 /*-
4 * Copyright (c) 1999 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
9 * NASA Ames Research Center.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the NetBSD
22 * Foundation, Inc. and its contributors.
23 * 4. Neither the name of The NetBSD Foundation nor the names of its
24 * contributors may be used to endorse or promote products derived
25 * from this software without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37 * POSSIBILITY OF SUCH DAMAGE.
38 */
39
40 /*
41 * Copyright (c) 1994 Adam Glass and Charles M. Hannum. All rights reserved.
42 *
43 * Redistribution and use in source and binary forms, with or without
44 * modification, are permitted provided that the following conditions
45 * are met:
46 * 1. Redistributions of source code must retain the above copyright
47 * notice, this list of conditions and the following disclaimer.
48 * 2. Redistributions in binary form must reproduce the above copyright
49 * notice, this list of conditions and the following disclaimer in the
50 * documentation and/or other materials provided with the distribution.
51 * 3. All advertising materials mentioning features or use of this software
52 * must display the following acknowledgement:
53 * This product includes software developed by Adam Glass and Charles M.
54 * Hannum.
55 * 4. The names of the authors may not be used to endorse or promote products
56 * derived from this software without specific prior written permission.
57 *
58 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
59 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
60 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
61 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
62 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
63 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
64 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
65 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
66 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
67 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
68 */
69
70 #include <sys/cdefs.h>
71 __KERNEL_RCSID(0, "$NetBSD: sysv_shm.c,v 1.82.10.1 2005/09/18 20:09:50 tron Exp $");
72
73 #define SYSVSHM
74
75 #include <sys/param.h>
76 #include <sys/kernel.h>
77 #include <sys/shm.h>
78 #include <sys/malloc.h>
79 #include <sys/mman.h>
80 #include <sys/stat.h>
81 #include <sys/sysctl.h>
82 #include <sys/mount.h> /* XXX for <sys/syscallargs.h> */
83 #include <sys/sa.h>
84 #include <sys/syscallargs.h>
85 #include <sys/queue.h>
86 #include <sys/pool.h>
87
88 #include <uvm/uvm_extern.h>
89 #include <uvm/uvm_object.h>
90
91 struct shmid_ds *shm_find_segment_by_shmid(int);
92
93 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments");
94
95 /*
96 * Provides the following externally accessible functions:
97 *
98 * shminit(void); initialization
99 * shmexit(struct vmspace *) cleanup
100 * shmfork(struct vmspace *, struct vmspace *) fork handling
101 *
102 * Structures:
103 * shmsegs (an array of 'struct shmid_ds')
104 * per proc array of 'struct shmmap_state'
105 */
106
107 #define SHMSEG_FREE 0x0200
108 #define SHMSEG_REMOVED 0x0400
109 #define SHMSEG_ALLOCATED 0x0800
110 #define SHMSEG_WANTED 0x1000
111 #define SHMSEG_RMLINGER 0x2000
112
113 static int shm_last_free, shm_nused, shm_committed;
114 struct shmid_ds *shmsegs;
115
116 struct shmmap_entry {
117 SLIST_ENTRY(shmmap_entry) next;
118 vaddr_t va;
119 int shmid;
120 };
121
122 static POOL_INIT(shmmap_entry_pool, sizeof(struct shmmap_entry), 0, 0, 0,
123 "shmmp", &pool_allocator_nointr);
124
125 struct shmmap_state {
126 unsigned int nitems;
127 unsigned int nrefs;
128 SLIST_HEAD(, shmmap_entry) entries;
129 };
130
131 static int shm_find_segment_by_key(key_t);
132 static void shm_deallocate_segment(struct shmid_ds *);
133 static void shm_delete_mapping(struct vmspace *, struct shmmap_state *,
134 struct shmmap_entry *);
135 static int shmget_existing(struct proc *, struct sys_shmget_args *,
136 int, int, register_t *);
137 static int shmget_allocate_segment(struct proc *, struct sys_shmget_args *,
138 int, register_t *);
139 static struct shmmap_state *shmmap_getprivate(struct proc *);
140 static struct shmmap_entry *shm_find_mapping(struct shmmap_state *, vaddr_t);
141
142 static int
143 shm_find_segment_by_key(key)
144 key_t key;
145 {
146 int i;
147
148 for (i = 0; i < shminfo.shmmni; i++)
149 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) &&
150 shmsegs[i].shm_perm._key == key)
151 return i;
152 return -1;
153 }
154
155 struct shmid_ds *
156 shm_find_segment_by_shmid(shmid)
157 int shmid;
158 {
159 int segnum;
160 struct shmid_ds *shmseg;
161
162 segnum = IPCID_TO_IX(shmid);
163 if (segnum < 0 || segnum >= shminfo.shmmni)
164 return NULL;
165 shmseg = &shmsegs[segnum];
166 if ((shmseg->shm_perm.mode & SHMSEG_ALLOCATED) == 0)
167 return NULL;
168 if ((shmseg->shm_perm.mode & (SHMSEG_REMOVED|SHMSEG_RMLINGER)) == SHMSEG_REMOVED)
169 return NULL;
170 if (shmseg->shm_perm._seq != IPCID_TO_SEQ(shmid))
171 return NULL;
172 return shmseg;
173 }
174
175 static void
176 shm_deallocate_segment(shmseg)
177 struct shmid_ds *shmseg;
178 {
179 struct uvm_object *uobj = shmseg->_shm_internal;
180 size_t size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET;
181
182 (*uobj->pgops->pgo_detach)(uobj);
183 shmseg->_shm_internal = NULL;
184 shm_committed -= btoc(size);
185 shmseg->shm_perm.mode = SHMSEG_FREE;
186 shm_nused--;
187 }
188
189 static void
190 shm_delete_mapping(vm, shmmap_s, shmmap_se)
191 struct vmspace *vm;
192 struct shmmap_state *shmmap_s;
193 struct shmmap_entry *shmmap_se;
194 {
195 struct shmid_ds *shmseg;
196 int segnum;
197 size_t size;
198
199 segnum = IPCID_TO_IX(shmmap_se->shmid);
200 #ifdef DEBUG
201 if (segnum < 0 || segnum >= shminfo.shmmni)
202 panic("shm_delete_mapping: vmspace %p state %p entry %p - "
203 "entry segment ID bad (%d)",
204 vm, shmmap_s, shmmap_se, segnum);
205 #endif
206 shmseg = &shmsegs[segnum];
207 size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET;
208 uvm_deallocate(&vm->vm_map, shmmap_se->va, size);
209 SLIST_REMOVE(&shmmap_s->entries, shmmap_se, shmmap_entry, next);
210 shmmap_s->nitems--;
211 pool_put(&shmmap_entry_pool, shmmap_se);
212 shmseg->shm_dtime = time.tv_sec;
213 if ((--shmseg->shm_nattch <= 0) &&
214 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) {
215 shm_deallocate_segment(shmseg);
216 shm_last_free = segnum;
217 }
218 }
219
220 /*
221 * Get a non-shared shm map for that vmspace.
222 * 3 cases:
223 * - no shm map present: create a fresh one
224 * - a shm map with refcount=1, just used by ourselves: fine
225 * - a shared shm map: copy to a fresh one and adjust refcounts
226 */
227 static struct shmmap_state *
228 shmmap_getprivate(struct proc *p)
229 {
230 struct shmmap_state *oshmmap_s, *shmmap_s;
231 struct shmmap_entry *oshmmap_se, *shmmap_se;
232
233 oshmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
234 if (oshmmap_s && oshmmap_s->nrefs == 1)
235 return (oshmmap_s);
236
237 shmmap_s = malloc(sizeof(struct shmmap_state), M_SHM, M_WAITOK);
238 memset(shmmap_s, 0, sizeof(struct shmmap_state));
239 shmmap_s->nrefs = 1;
240 SLIST_INIT(&shmmap_s->entries);
241 p->p_vmspace->vm_shm = (caddr_t)shmmap_s;
242
243 if (!oshmmap_s)
244 return (shmmap_s);
245
246 #ifdef SHMDEBUG
247 printf("shmmap_getprivate: vm %p split (%d entries), was used by %d\n",
248 p->p_vmspace, oshmmap_s->nitems, oshmmap_s->nrefs);
249 #endif
250 SLIST_FOREACH(oshmmap_se, &oshmmap_s->entries, next) {
251 shmmap_se = pool_get(&shmmap_entry_pool, PR_WAITOK);
252 shmmap_se->va = oshmmap_se->va;
253 shmmap_se->shmid = oshmmap_se->shmid;
254 SLIST_INSERT_HEAD(&shmmap_s->entries, shmmap_se, next);
255 }
256 shmmap_s->nitems = oshmmap_s->nitems;
257 oshmmap_s->nrefs--;
258 return (shmmap_s);
259 }
260
261 static struct shmmap_entry *
262 shm_find_mapping(map, va)
263 struct shmmap_state *map;
264 vaddr_t va;
265 {
266 struct shmmap_entry *shmmap_se;
267
268 SLIST_FOREACH(shmmap_se, &map->entries, next) {
269 if (shmmap_se->va == va)
270 return shmmap_se;
271 }
272 return 0;
273 }
274
275 int
276 sys_shmdt(l, v, retval)
277 struct lwp *l;
278 void *v;
279 register_t *retval;
280 {
281 struct sys_shmdt_args /* {
282 syscallarg(const void *) shmaddr;
283 } */ *uap = v;
284 struct proc *p = l->l_proc;
285 struct shmmap_state *shmmap_s, *shmmap_s1;
286 struct shmmap_entry *shmmap_se;
287
288 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
289 if (shmmap_s == NULL)
290 return EINVAL;
291
292 shmmap_se = shm_find_mapping(shmmap_s, (vaddr_t)SCARG(uap, shmaddr));
293 if (!shmmap_se)
294 return EINVAL;
295
296 shmmap_s1 = shmmap_getprivate(p);
297 if (shmmap_s1 != shmmap_s) {
298 /* map has been copied, lookup entry in new map */
299 shmmap_se = shm_find_mapping(shmmap_s1,
300 (vaddr_t)SCARG(uap, shmaddr));
301 KASSERT(shmmap_se != NULL);
302 }
303 #ifdef SHMDEBUG
304 printf("shmdt: vm %p: remove %d @%lx\n",
305 p->p_vmspace, shmmap_se->shmid, shmmap_se->va);
306 #endif
307 shm_delete_mapping(p->p_vmspace, shmmap_s1, shmmap_se);
308 return 0;
309 }
310
311 int
312 sys_shmat(l, v, retval)
313 struct lwp *l;
314 void *v;
315 register_t *retval;
316 {
317 struct sys_shmat_args /* {
318 syscallarg(int) shmid;
319 syscallarg(const void *) shmaddr;
320 syscallarg(int) shmflg;
321 } */ *uap = v;
322 int error, flags;
323 struct proc *p = l->l_proc;
324 struct ucred *cred = p->p_ucred;
325 struct shmid_ds *shmseg;
326 struct shmmap_state *shmmap_s;
327 struct uvm_object *uobj;
328 vaddr_t attach_va;
329 vm_prot_t prot;
330 vsize_t size;
331 struct shmmap_entry *shmmap_se;
332
333 shmseg = shm_find_segment_by_shmid(SCARG(uap, shmid));
334 if (shmseg == NULL)
335 return EINVAL;
336 error = ipcperm(cred, &shmseg->shm_perm,
337 (SCARG(uap, shmflg) & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
338 if (error)
339 return error;
340
341 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
342 if (shmmap_s && shmmap_s->nitems >= shminfo.shmseg)
343 return EMFILE;
344
345 size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET;
346 prot = VM_PROT_READ;
347 if ((SCARG(uap, shmflg) & SHM_RDONLY) == 0)
348 prot |= VM_PROT_WRITE;
349 flags = MAP_ANON | MAP_SHARED;
350 if (SCARG(uap, shmaddr)) {
351 flags |= MAP_FIXED;
352 if (SCARG(uap, shmflg) & SHM_RND)
353 attach_va =
354 (vaddr_t)SCARG(uap, shmaddr) & ~(SHMLBA-1);
355 else if (((vaddr_t)SCARG(uap, shmaddr) & (SHMLBA-1)) == 0)
356 attach_va = (vaddr_t)SCARG(uap, shmaddr);
357 else
358 return EINVAL;
359 } else {
360 /* This is just a hint to uvm_mmap() about where to put it. */
361 attach_va = p->p_emul->e_vm_default_addr(p,
362 (vaddr_t)p->p_vmspace->vm_daddr, size);
363 }
364 uobj = shmseg->_shm_internal;
365 (*uobj->pgops->pgo_reference)(uobj);
366 error = uvm_map(&p->p_vmspace->vm_map, &attach_va, size,
367 uobj, 0, 0,
368 UVM_MAPFLAG(prot, prot, UVM_INH_SHARE, UVM_ADV_RANDOM, 0));
369 if (error) {
370 (*uobj->pgops->pgo_detach)(uobj);
371 return error;
372 }
373 shmmap_se = pool_get(&shmmap_entry_pool, PR_WAITOK);
374 shmmap_se->va = attach_va;
375 shmmap_se->shmid = SCARG(uap, shmid);
376 shmmap_s = shmmap_getprivate(p);
377 #ifdef SHMDEBUG
378 printf("shmat: vm %p: add %d @%lx\n", p->p_vmspace, shmid, attach_va);
379 #endif
380 SLIST_INSERT_HEAD(&shmmap_s->entries, shmmap_se, next);
381 shmmap_s->nitems++;
382 shmseg->shm_lpid = p->p_pid;
383 shmseg->shm_atime = time.tv_sec;
384 shmseg->shm_nattch++;
385
386 retval[0] = attach_va;
387 return 0;
388 }
389
390 int
391 sys___shmctl13(l, v, retval)
392 struct lwp *l;
393 void *v;
394 register_t *retval;
395 {
396 struct sys___shmctl13_args /* {
397 syscallarg(int) shmid;
398 syscallarg(int) cmd;
399 syscallarg(struct shmid_ds *) buf;
400 } */ *uap = v;
401 struct proc *p = l->l_proc;
402 struct shmid_ds shmbuf;
403 int cmd, error;
404
405 cmd = SCARG(uap, cmd);
406
407 if (cmd == IPC_SET) {
408 error = copyin(SCARG(uap, buf), &shmbuf, sizeof(shmbuf));
409 if (error)
410 return (error);
411 }
412
413 error = shmctl1(p, SCARG(uap, shmid), cmd,
414 (cmd == IPC_SET || cmd == IPC_STAT) ? &shmbuf : NULL);
415
416 if (error == 0 && cmd == IPC_STAT)
417 error = copyout(&shmbuf, SCARG(uap, buf), sizeof(shmbuf));
418
419 return (error);
420 }
421
422 int
423 shmctl1(p, shmid, cmd, shmbuf)
424 struct proc *p;
425 int shmid;
426 int cmd;
427 struct shmid_ds *shmbuf;
428 {
429 struct ucred *cred = p->p_ucred;
430 struct shmid_ds *shmseg;
431 int error = 0;
432
433 shmseg = shm_find_segment_by_shmid(shmid);
434 if (shmseg == NULL)
435 return EINVAL;
436 switch (cmd) {
437 case IPC_STAT:
438 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_R)) != 0)
439 return error;
440 memcpy(shmbuf, shmseg, sizeof(struct shmid_ds));
441 break;
442 case IPC_SET:
443 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0)
444 return error;
445 shmseg->shm_perm.uid = shmbuf->shm_perm.uid;
446 shmseg->shm_perm.gid = shmbuf->shm_perm.gid;
447 shmseg->shm_perm.mode =
448 (shmseg->shm_perm.mode & ~ACCESSPERMS) |
449 (shmbuf->shm_perm.mode & ACCESSPERMS);
450 shmseg->shm_ctime = time.tv_sec;
451 break;
452 case IPC_RMID:
453 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0)
454 return error;
455 shmseg->shm_perm._key = IPC_PRIVATE;
456 shmseg->shm_perm.mode |= SHMSEG_REMOVED;
457 if (shmseg->shm_nattch <= 0) {
458 shm_deallocate_segment(shmseg);
459 shm_last_free = IPCID_TO_IX(shmid);
460 }
461 break;
462 case SHM_LOCK:
463 case SHM_UNLOCK:
464 default:
465 return EINVAL;
466 }
467 return 0;
468 }
469
470 static int
471 shmget_existing(p, uap, mode, segnum, retval)
472 struct proc *p;
473 struct sys_shmget_args /* {
474 syscallarg(key_t) key;
475 syscallarg(size_t) size;
476 syscallarg(int) shmflg;
477 } */ *uap;
478 int mode;
479 int segnum;
480 register_t *retval;
481 {
482 struct shmid_ds *shmseg;
483 struct ucred *cred = p->p_ucred;
484 int error;
485
486 shmseg = &shmsegs[segnum];
487 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) {
488 /*
489 * This segment is in the process of being allocated. Wait
490 * until it's done, and look the key up again (in case the
491 * allocation failed or it was freed).
492 */
493 shmseg->shm_perm.mode |= SHMSEG_WANTED;
494 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0);
495 if (error)
496 return error;
497 return EAGAIN;
498 }
499 if ((error = ipcperm(cred, &shmseg->shm_perm, mode)) != 0)
500 return error;
501 if (SCARG(uap, size) && SCARG(uap, size) > shmseg->shm_segsz)
502 return EINVAL;
503 if ((SCARG(uap, shmflg) & (IPC_CREAT | IPC_EXCL)) ==
504 (IPC_CREAT | IPC_EXCL))
505 return EEXIST;
506 *retval = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
507 return 0;
508 }
509
510 static int
511 shmget_allocate_segment(p, uap, mode, retval)
512 struct proc *p;
513 struct sys_shmget_args /* {
514 syscallarg(key_t) key;
515 syscallarg(size_t) size;
516 syscallarg(int) shmflg;
517 } */ *uap;
518 int mode;
519 register_t *retval;
520 {
521 int i, segnum, shmid, size;
522 struct ucred *cred = p->p_ucred;
523 struct shmid_ds *shmseg;
524 int error = 0;
525
526 if (SCARG(uap, size) < shminfo.shmmin ||
527 SCARG(uap, size) > shminfo.shmmax)
528 return EINVAL;
529 if (shm_nused >= shminfo.shmmni) /* any shmids left? */
530 return ENOSPC;
531 size = (SCARG(uap, size) + PGOFSET) & ~PGOFSET;
532 if (shm_committed + btoc(size) > shminfo.shmall)
533 return ENOMEM;
534 if (shm_last_free < 0) {
535 for (i = 0; i < shminfo.shmmni; i++)
536 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
537 break;
538 if (i == shminfo.shmmni)
539 panic("shmseg free count inconsistent");
540 segnum = i;
541 } else {
542 segnum = shm_last_free;
543 shm_last_free = -1;
544 }
545 shmseg = &shmsegs[segnum];
546 /*
547 * In case we sleep in malloc(), mark the segment present but deleted
548 * so that noone else tries to create the same key.
549 */
550 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
551 shmseg->shm_perm._key = SCARG(uap, key);
552 shmseg->shm_perm._seq = (shmseg->shm_perm._seq + 1) & 0x7fff;
553 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
554
555 shmseg->_shm_internal = uao_create(size, 0);
556
557 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid;
558 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid;
559 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
560 (mode & (ACCESSPERMS|SHMSEG_RMLINGER)) | SHMSEG_ALLOCATED;
561 shmseg->shm_segsz = SCARG(uap, size);
562 shmseg->shm_cpid = p->p_pid;
563 shmseg->shm_lpid = shmseg->shm_nattch = 0;
564 shmseg->shm_atime = shmseg->shm_dtime = 0;
565 shmseg->shm_ctime = time.tv_sec;
566 shm_committed += btoc(size);
567 shm_nused++;
568
569 *retval = shmid;
570 if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
571 /*
572 * Somebody else wanted this key while we were asleep. Wake
573 * them up now.
574 */
575 shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
576 wakeup((caddr_t)shmseg);
577 }
578 return error;
579 }
580
581 int
582 sys_shmget(l, v, retval)
583 struct lwp *l;
584 void *v;
585 register_t *retval;
586 {
587 struct sys_shmget_args /* {
588 syscallarg(key_t) key;
589 syscallarg(int) size;
590 syscallarg(int) shmflg;
591 } */ *uap = v;
592 struct proc *p = l->l_proc;
593 int segnum, mode, error;
594
595 mode = SCARG(uap, shmflg) & ACCESSPERMS;
596 if (SCARG(uap, shmflg) & _SHM_RMLINGER)
597 mode |= SHMSEG_RMLINGER;
598
599 if (SCARG(uap, key) != IPC_PRIVATE) {
600 again:
601 segnum = shm_find_segment_by_key(SCARG(uap, key));
602 if (segnum >= 0) {
603 error = shmget_existing(p, uap, mode, segnum, retval);
604 if (error == EAGAIN)
605 goto again;
606 return error;
607 }
608 if ((SCARG(uap, shmflg) & IPC_CREAT) == 0)
609 return ENOENT;
610 }
611 return shmget_allocate_segment(p, uap, mode, retval);
612 }
613
614 void
615 shmfork(vm1, vm2)
616 struct vmspace *vm1, *vm2;
617 {
618 struct shmmap_state *shmmap_s;
619 struct shmmap_entry *shmmap_se;
620
621 vm2->vm_shm = vm1->vm_shm;
622
623 if (vm1->vm_shm == NULL)
624 return;
625
626 #ifdef SHMDEBUG
627 printf("shmfork %p->%p\n", vm1, vm2);
628 #endif
629
630 shmmap_s = (struct shmmap_state *)vm1->vm_shm;
631
632 SLIST_FOREACH(shmmap_se, &shmmap_s->entries, next)
633 shmsegs[IPCID_TO_IX(shmmap_se->shmid)].shm_nattch++;
634 shmmap_s->nrefs++;
635 }
636
637 void
638 shmexit(vm)
639 struct vmspace *vm;
640 {
641 struct shmmap_state *shmmap_s;
642 struct shmmap_entry *shmmap_se;
643
644 shmmap_s = (struct shmmap_state *)vm->vm_shm;
645 if (shmmap_s == NULL)
646 return;
647
648 vm->vm_shm = NULL;
649
650 if (--shmmap_s->nrefs > 0) {
651 #ifdef SHMDEBUG
652 printf("shmexit: vm %p drop ref (%d entries), now used by %d\n",
653 vm, shmmap_s->nitems, shmmap_s->nrefs);
654 #endif
655 SLIST_FOREACH(shmmap_se, &shmmap_s->entries, next)
656 shmsegs[IPCID_TO_IX(shmmap_se->shmid)].shm_nattch--;
657 return;
658 }
659
660 #ifdef SHMDEBUG
661 printf("shmexit: vm %p cleanup (%d entries)\n", vm, shmmap_s->nitems);
662 #endif
663 while (!SLIST_EMPTY(&shmmap_s->entries)) {
664 shmmap_se = SLIST_FIRST(&shmmap_s->entries);
665 shm_delete_mapping(vm, shmmap_s, shmmap_se);
666 }
667 KASSERT(shmmap_s->nitems == 0);
668 free(shmmap_s, M_SHM);
669 }
670
671 void
672 shminit()
673 {
674 int i, sz;
675 vaddr_t v;
676
677 /* Allocate pageable memory for our structures */
678 sz = shminfo.shmmni * sizeof(struct shmid_ds);
679 if ((v = uvm_km_alloc(kernel_map, round_page(sz))) == 0)
680 panic("sysv_shm: cannot allocate memory");
681 shmsegs = (void *)v;
682
683 shminfo.shmmax *= PAGE_SIZE;
684
685 for (i = 0; i < shminfo.shmmni; i++) {
686 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
687 shmsegs[i].shm_perm._seq = 0;
688 }
689 shm_last_free = 0;
690 shm_nused = 0;
691 shm_committed = 0;
692 }
Cache object: 63468d3878f4417a08f8d9cbb3f67ca6
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