FreeBSD/Linux Kernel Cross Reference
sys/kern/sysv_shm.c
1 /* $NetBSD: sysv_shm.c,v 1.23 1994/07/04 23:25:12 glass Exp $ */
2 /*-
3 * Copyright (c) 1994 Adam Glass and Charles Hannum. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by Adam Glass and Charles
16 * Hannum.
17 * 4. The names of the authors may not be used to endorse or promote products
18 * derived from this software without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
29 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31 /*-
32 * Copyright (c) 2003-2005 McAfee, Inc.
33 * All rights reserved.
34 *
35 * This software was developed for the FreeBSD Project in part by McAfee
36 * Research, the Security Research Division of McAfee, Inc under DARPA/SPAWAR
37 * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS research
38 * program.
39 *
40 * Redistribution and use in source and binary forms, with or without
41 * modification, are permitted provided that the following conditions
42 * are met:
43 * 1. Redistributions of source code must retain the above copyright
44 * notice, this list of conditions and the following disclaimer.
45 * 2. Redistributions in binary form must reproduce the above copyright
46 * notice, this list of conditions and the following disclaimer in the
47 * documentation and/or other materials provided with the distribution.
48 *
49 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
50 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
51 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
52 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
53 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
54 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
55 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
56 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
57 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
58 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
59 * SUCH DAMAGE.
60 */
61
62 #include <sys/cdefs.h>
63 __FBSDID("$FreeBSD: releng/8.0/sys/kern/sysv_shm.c 194976 2009-06-25 17:11:27Z jhb $");
64
65 #include "opt_compat.h"
66 #include "opt_sysvipc.h"
67
68 #include <sys/param.h>
69 #include <sys/systm.h>
70 #include <sys/kernel.h>
71 #include <sys/limits.h>
72 #include <sys/lock.h>
73 #include <sys/sysctl.h>
74 #include <sys/shm.h>
75 #include <sys/proc.h>
76 #include <sys/malloc.h>
77 #include <sys/mman.h>
78 #include <sys/module.h>
79 #include <sys/mutex.h>
80 #include <sys/resourcevar.h>
81 #include <sys/stat.h>
82 #include <sys/syscall.h>
83 #include <sys/syscallsubr.h>
84 #include <sys/sysent.h>
85 #include <sys/sysproto.h>
86 #include <sys/jail.h>
87
88 #include <security/mac/mac_framework.h>
89
90 #include <vm/vm.h>
91 #include <vm/vm_param.h>
92 #include <vm/pmap.h>
93 #include <vm/vm_object.h>
94 #include <vm/vm_map.h>
95 #include <vm/vm_page.h>
96 #include <vm/vm_pager.h>
97
98 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments");
99
100 static int shmget_allocate_segment(struct thread *td,
101 struct shmget_args *uap, int mode);
102 static int shmget_existing(struct thread *td, struct shmget_args *uap,
103 int mode, int segnum);
104
105 #define SHMSEG_FREE 0x0200
106 #define SHMSEG_REMOVED 0x0400
107 #define SHMSEG_ALLOCATED 0x0800
108 #define SHMSEG_WANTED 0x1000
109
110 static int shm_last_free, shm_nused, shmalloced;
111 vm_size_t shm_committed;
112 static struct shmid_kernel *shmsegs;
113
114 struct shmmap_state {
115 vm_offset_t va;
116 int shmid;
117 };
118
119 static void shm_deallocate_segment(struct shmid_kernel *);
120 static int shm_find_segment_by_key(key_t);
121 static struct shmid_kernel *shm_find_segment_by_shmid(int);
122 static struct shmid_kernel *shm_find_segment_by_shmidx(int);
123 static int shm_delete_mapping(struct vmspace *vm, struct shmmap_state *);
124 static void shmrealloc(void);
125 static void shminit(void);
126 static int sysvshm_modload(struct module *, int, void *);
127 static int shmunload(void);
128 static void shmexit_myhook(struct vmspace *vm);
129 static void shmfork_myhook(struct proc *p1, struct proc *p2);
130 static int sysctl_shmsegs(SYSCTL_HANDLER_ARGS);
131
132 /*
133 * Tuneable values.
134 */
135 #ifndef SHMMAXPGS
136 #define SHMMAXPGS 8192 /* Note: sysv shared memory is swap backed. */
137 #endif
138 #ifndef SHMMAX
139 #define SHMMAX (SHMMAXPGS*PAGE_SIZE)
140 #endif
141 #ifndef SHMMIN
142 #define SHMMIN 1
143 #endif
144 #ifndef SHMMNI
145 #define SHMMNI 192
146 #endif
147 #ifndef SHMSEG
148 #define SHMSEG 128
149 #endif
150 #ifndef SHMALL
151 #define SHMALL (SHMMAXPGS)
152 #endif
153
154 struct shminfo shminfo = {
155 SHMMAX,
156 SHMMIN,
157 SHMMNI,
158 SHMSEG,
159 SHMALL
160 };
161
162 static int shm_use_phys;
163 static int shm_allow_removed;
164
165 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0,
166 "Maximum shared memory segment size");
167 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0,
168 "Minimum shared memory segment size");
169 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RDTUN, &shminfo.shmmni, 0,
170 "Number of shared memory identifiers");
171 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RDTUN, &shminfo.shmseg, 0,
172 "Number of segments per process");
173 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0,
174 "Maximum number of pages available for shared memory");
175 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW,
176 &shm_use_phys, 0, "Enable/Disable locking of shared memory pages in core");
177 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_allow_removed, CTLFLAG_RW,
178 &shm_allow_removed, 0,
179 "Enable/Disable attachment to attached segments marked for removal");
180 SYSCTL_PROC(_kern_ipc, OID_AUTO, shmsegs, CTLFLAG_RD,
181 NULL, 0, sysctl_shmsegs, "",
182 "Current number of shared memory segments allocated");
183
184 static int
185 shm_find_segment_by_key(key)
186 key_t key;
187 {
188 int i;
189
190 for (i = 0; i < shmalloced; i++)
191 if ((shmsegs[i].u.shm_perm.mode & SHMSEG_ALLOCATED) &&
192 shmsegs[i].u.shm_perm.key == key)
193 return (i);
194 return (-1);
195 }
196
197 static struct shmid_kernel *
198 shm_find_segment_by_shmid(int shmid)
199 {
200 int segnum;
201 struct shmid_kernel *shmseg;
202
203 segnum = IPCID_TO_IX(shmid);
204 if (segnum < 0 || segnum >= shmalloced)
205 return (NULL);
206 shmseg = &shmsegs[segnum];
207 if ((shmseg->u.shm_perm.mode & SHMSEG_ALLOCATED) == 0 ||
208 (!shm_allow_removed &&
209 (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) != 0) ||
210 shmseg->u.shm_perm.seq != IPCID_TO_SEQ(shmid))
211 return (NULL);
212 return (shmseg);
213 }
214
215 static struct shmid_kernel *
216 shm_find_segment_by_shmidx(int segnum)
217 {
218 struct shmid_kernel *shmseg;
219
220 if (segnum < 0 || segnum >= shmalloced)
221 return (NULL);
222 shmseg = &shmsegs[segnum];
223 if ((shmseg->u.shm_perm.mode & SHMSEG_ALLOCATED) == 0 ||
224 (!shm_allow_removed &&
225 (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) != 0))
226 return (NULL);
227 return (shmseg);
228 }
229
230 static void
231 shm_deallocate_segment(shmseg)
232 struct shmid_kernel *shmseg;
233 {
234 vm_size_t size;
235
236 GIANT_REQUIRED;
237
238 vm_object_deallocate(shmseg->object);
239 shmseg->object = NULL;
240 size = round_page(shmseg->u.shm_segsz);
241 shm_committed -= btoc(size);
242 shm_nused--;
243 shmseg->u.shm_perm.mode = SHMSEG_FREE;
244 #ifdef MAC
245 mac_sysvshm_cleanup(shmseg);
246 #endif
247 }
248
249 static int
250 shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s)
251 {
252 struct shmid_kernel *shmseg;
253 int segnum, result;
254 vm_size_t size;
255
256 GIANT_REQUIRED;
257
258 segnum = IPCID_TO_IX(shmmap_s->shmid);
259 shmseg = &shmsegs[segnum];
260 size = round_page(shmseg->u.shm_segsz);
261 result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size);
262 if (result != KERN_SUCCESS)
263 return (EINVAL);
264 shmmap_s->shmid = -1;
265 shmseg->u.shm_dtime = time_second;
266 if ((--shmseg->u.shm_nattch <= 0) &&
267 (shmseg->u.shm_perm.mode & SHMSEG_REMOVED)) {
268 shm_deallocate_segment(shmseg);
269 shm_last_free = segnum;
270 }
271 return (0);
272 }
273
274 #ifndef _SYS_SYSPROTO_H_
275 struct shmdt_args {
276 const void *shmaddr;
277 };
278 #endif
279 int
280 shmdt(td, uap)
281 struct thread *td;
282 struct shmdt_args *uap;
283 {
284 struct proc *p = td->td_proc;
285 struct shmmap_state *shmmap_s;
286 #ifdef MAC
287 struct shmid_kernel *shmsegptr;
288 #endif
289 int i;
290 int error = 0;
291
292 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
293 return (ENOSYS);
294 mtx_lock(&Giant);
295 shmmap_s = p->p_vmspace->vm_shm;
296 if (shmmap_s == NULL) {
297 error = EINVAL;
298 goto done2;
299 }
300 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) {
301 if (shmmap_s->shmid != -1 &&
302 shmmap_s->va == (vm_offset_t)uap->shmaddr) {
303 break;
304 }
305 }
306 if (i == shminfo.shmseg) {
307 error = EINVAL;
308 goto done2;
309 }
310 #ifdef MAC
311 shmsegptr = &shmsegs[IPCID_TO_IX(shmmap_s->shmid)];
312 error = mac_sysvshm_check_shmdt(td->td_ucred, shmsegptr);
313 if (error != 0)
314 goto done2;
315 #endif
316 error = shm_delete_mapping(p->p_vmspace, shmmap_s);
317 done2:
318 mtx_unlock(&Giant);
319 return (error);
320 }
321
322 #ifndef _SYS_SYSPROTO_H_
323 struct shmat_args {
324 int shmid;
325 const void *shmaddr;
326 int shmflg;
327 };
328 #endif
329 int
330 kern_shmat(td, shmid, shmaddr, shmflg)
331 struct thread *td;
332 int shmid;
333 const void *shmaddr;
334 int shmflg;
335 {
336 struct proc *p = td->td_proc;
337 int i, flags;
338 struct shmid_kernel *shmseg;
339 struct shmmap_state *shmmap_s = NULL;
340 vm_offset_t attach_va;
341 vm_prot_t prot;
342 vm_size_t size;
343 int rv;
344 int error = 0;
345
346 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
347 return (ENOSYS);
348 mtx_lock(&Giant);
349 shmmap_s = p->p_vmspace->vm_shm;
350 if (shmmap_s == NULL) {
351 shmmap_s = malloc(shminfo.shmseg * sizeof(struct shmmap_state),
352 M_SHM, M_WAITOK);
353 for (i = 0; i < shminfo.shmseg; i++)
354 shmmap_s[i].shmid = -1;
355 p->p_vmspace->vm_shm = shmmap_s;
356 }
357 shmseg = shm_find_segment_by_shmid(shmid);
358 if (shmseg == NULL) {
359 error = EINVAL;
360 goto done2;
361 }
362 error = ipcperm(td, &shmseg->u.shm_perm,
363 (shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
364 if (error)
365 goto done2;
366 #ifdef MAC
367 error = mac_sysvshm_check_shmat(td->td_ucred, shmseg, shmflg);
368 if (error != 0)
369 goto done2;
370 #endif
371 for (i = 0; i < shminfo.shmseg; i++) {
372 if (shmmap_s->shmid == -1)
373 break;
374 shmmap_s++;
375 }
376 if (i >= shminfo.shmseg) {
377 error = EMFILE;
378 goto done2;
379 }
380 size = round_page(shmseg->u.shm_segsz);
381 prot = VM_PROT_READ;
382 if ((shmflg & SHM_RDONLY) == 0)
383 prot |= VM_PROT_WRITE;
384 flags = MAP_ANON | MAP_SHARED;
385 if (shmaddr) {
386 flags |= MAP_FIXED;
387 if (shmflg & SHM_RND) {
388 attach_va = (vm_offset_t)shmaddr & ~(SHMLBA-1);
389 } else if (((vm_offset_t)shmaddr & (SHMLBA-1)) == 0) {
390 attach_va = (vm_offset_t)shmaddr;
391 } else {
392 error = EINVAL;
393 goto done2;
394 }
395 } else {
396 /*
397 * This is just a hint to vm_map_find() about where to
398 * put it.
399 */
400 PROC_LOCK(p);
401 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_daddr +
402 lim_max(p, RLIMIT_DATA));
403 PROC_UNLOCK(p);
404 }
405
406 vm_object_reference(shmseg->object);
407 rv = vm_map_find(&p->p_vmspace->vm_map, shmseg->object,
408 0, &attach_va, size, (flags & MAP_FIXED) ? VMFS_NO_SPACE :
409 VMFS_ANY_SPACE, prot, prot, 0);
410 if (rv != KERN_SUCCESS) {
411 vm_object_deallocate(shmseg->object);
412 error = ENOMEM;
413 goto done2;
414 }
415 vm_map_inherit(&p->p_vmspace->vm_map,
416 attach_va, attach_va + size, VM_INHERIT_SHARE);
417
418 shmmap_s->va = attach_va;
419 shmmap_s->shmid = shmid;
420 shmseg->u.shm_lpid = p->p_pid;
421 shmseg->u.shm_atime = time_second;
422 shmseg->u.shm_nattch++;
423 td->td_retval[0] = attach_va;
424 done2:
425 mtx_unlock(&Giant);
426 return (error);
427 }
428
429 int
430 shmat(td, uap)
431 struct thread *td;
432 struct shmat_args *uap;
433 {
434 return kern_shmat(td, uap->shmid, uap->shmaddr, uap->shmflg);
435 }
436
437 int
438 kern_shmctl(td, shmid, cmd, buf, bufsz)
439 struct thread *td;
440 int shmid;
441 int cmd;
442 void *buf;
443 size_t *bufsz;
444 {
445 int error = 0;
446 struct shmid_kernel *shmseg;
447
448 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
449 return (ENOSYS);
450
451 mtx_lock(&Giant);
452 switch (cmd) {
453 /*
454 * It is possible that kern_shmctl is being called from the Linux ABI
455 * layer, in which case, we will need to implement IPC_INFO. It should
456 * be noted that other shmctl calls will be funneled through here for
457 * Linix binaries as well.
458 *
459 * NB: The Linux ABI layer will convert this data to structure(s) more
460 * consistent with the Linux ABI.
461 */
462 case IPC_INFO:
463 memcpy(buf, &shminfo, sizeof(shminfo));
464 if (bufsz)
465 *bufsz = sizeof(shminfo);
466 td->td_retval[0] = shmalloced;
467 goto done2;
468 case SHM_INFO: {
469 struct shm_info shm_info;
470 shm_info.used_ids = shm_nused;
471 shm_info.shm_rss = 0; /*XXX where to get from ? */
472 shm_info.shm_tot = 0; /*XXX where to get from ? */
473 shm_info.shm_swp = 0; /*XXX where to get from ? */
474 shm_info.swap_attempts = 0; /*XXX where to get from ? */
475 shm_info.swap_successes = 0; /*XXX where to get from ? */
476 memcpy(buf, &shm_info, sizeof(shm_info));
477 if (bufsz)
478 *bufsz = sizeof(shm_info);
479 td->td_retval[0] = shmalloced;
480 goto done2;
481 }
482 }
483 if (cmd == SHM_STAT)
484 shmseg = shm_find_segment_by_shmidx(shmid);
485 else
486 shmseg = shm_find_segment_by_shmid(shmid);
487 if (shmseg == NULL) {
488 error = EINVAL;
489 goto done2;
490 }
491 #ifdef MAC
492 error = mac_sysvshm_check_shmctl(td->td_ucred, shmseg, cmd);
493 if (error != 0)
494 goto done2;
495 #endif
496 switch (cmd) {
497 case SHM_STAT:
498 case IPC_STAT:
499 error = ipcperm(td, &shmseg->u.shm_perm, IPC_R);
500 if (error)
501 goto done2;
502 memcpy(buf, &shmseg->u, sizeof(struct shmid_ds));
503 if (bufsz)
504 *bufsz = sizeof(struct shmid_ds);
505 if (cmd == SHM_STAT)
506 td->td_retval[0] = IXSEQ_TO_IPCID(shmid, shmseg->u.shm_perm);
507 break;
508 case IPC_SET: {
509 struct shmid_ds *shmid;
510
511 shmid = (struct shmid_ds *)buf;
512 error = ipcperm(td, &shmseg->u.shm_perm, IPC_M);
513 if (error)
514 goto done2;
515 shmseg->u.shm_perm.uid = shmid->shm_perm.uid;
516 shmseg->u.shm_perm.gid = shmid->shm_perm.gid;
517 shmseg->u.shm_perm.mode =
518 (shmseg->u.shm_perm.mode & ~ACCESSPERMS) |
519 (shmid->shm_perm.mode & ACCESSPERMS);
520 shmseg->u.shm_ctime = time_second;
521 break;
522 }
523 case IPC_RMID:
524 error = ipcperm(td, &shmseg->u.shm_perm, IPC_M);
525 if (error)
526 goto done2;
527 shmseg->u.shm_perm.key = IPC_PRIVATE;
528 shmseg->u.shm_perm.mode |= SHMSEG_REMOVED;
529 if (shmseg->u.shm_nattch <= 0) {
530 shm_deallocate_segment(shmseg);
531 shm_last_free = IPCID_TO_IX(shmid);
532 }
533 break;
534 #if 0
535 case SHM_LOCK:
536 case SHM_UNLOCK:
537 #endif
538 default:
539 error = EINVAL;
540 break;
541 }
542 done2:
543 mtx_unlock(&Giant);
544 return (error);
545 }
546
547 #ifndef _SYS_SYSPROTO_H_
548 struct shmctl_args {
549 int shmid;
550 int cmd;
551 struct shmid_ds *buf;
552 };
553 #endif
554 int
555 shmctl(td, uap)
556 struct thread *td;
557 struct shmctl_args *uap;
558 {
559 int error = 0;
560 struct shmid_ds buf;
561 size_t bufsz;
562
563 /*
564 * The only reason IPC_INFO, SHM_INFO, SHM_STAT exists is to support
565 * Linux binaries. If we see the call come through the FreeBSD ABI,
566 * return an error back to the user since we do not to support this.
567 */
568 if (uap->cmd == IPC_INFO || uap->cmd == SHM_INFO ||
569 uap->cmd == SHM_STAT)
570 return (EINVAL);
571
572 /* IPC_SET needs to copyin the buffer before calling kern_shmctl */
573 if (uap->cmd == IPC_SET) {
574 if ((error = copyin(uap->buf, &buf, sizeof(struct shmid_ds))))
575 goto done;
576 }
577
578 error = kern_shmctl(td, uap->shmid, uap->cmd, (void *)&buf, &bufsz);
579 if (error)
580 goto done;
581
582 /* Cases in which we need to copyout */
583 switch (uap->cmd) {
584 case IPC_STAT:
585 error = copyout(&buf, uap->buf, bufsz);
586 break;
587 }
588
589 done:
590 if (error) {
591 /* Invalidate the return value */
592 td->td_retval[0] = -1;
593 }
594 return (error);
595 }
596
597
598 static int
599 shmget_existing(td, uap, mode, segnum)
600 struct thread *td;
601 struct shmget_args *uap;
602 int mode;
603 int segnum;
604 {
605 struct shmid_kernel *shmseg;
606 int error;
607
608 shmseg = &shmsegs[segnum];
609 if (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) {
610 /*
611 * This segment is in the process of being allocated. Wait
612 * until it's done, and look the key up again (in case the
613 * allocation failed or it was freed).
614 */
615 shmseg->u.shm_perm.mode |= SHMSEG_WANTED;
616 error = tsleep(shmseg, PLOCK | PCATCH, "shmget", 0);
617 if (error)
618 return (error);
619 return (EAGAIN);
620 }
621 if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
622 return (EEXIST);
623 #ifdef MAC
624 error = mac_sysvshm_check_shmget(td->td_ucred, shmseg, uap->shmflg);
625 if (error != 0)
626 return (error);
627 #endif
628 if (uap->size != 0 && uap->size > shmseg->u.shm_segsz)
629 return (EINVAL);
630 td->td_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm);
631 return (0);
632 }
633
634 static int
635 shmget_allocate_segment(td, uap, mode)
636 struct thread *td;
637 struct shmget_args *uap;
638 int mode;
639 {
640 int i, segnum, shmid;
641 size_t size;
642 struct ucred *cred = td->td_ucred;
643 struct shmid_kernel *shmseg;
644 vm_object_t shm_object;
645
646 GIANT_REQUIRED;
647
648 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
649 return (EINVAL);
650 if (shm_nused >= shminfo.shmmni) /* Any shmids left? */
651 return (ENOSPC);
652 size = round_page(uap->size);
653 if (shm_committed + btoc(size) > shminfo.shmall)
654 return (ENOMEM);
655 if (shm_last_free < 0) {
656 shmrealloc(); /* Maybe expand the shmsegs[] array. */
657 for (i = 0; i < shmalloced; i++)
658 if (shmsegs[i].u.shm_perm.mode & SHMSEG_FREE)
659 break;
660 if (i == shmalloced)
661 return (ENOSPC);
662 segnum = i;
663 } else {
664 segnum = shm_last_free;
665 shm_last_free = -1;
666 }
667 shmseg = &shmsegs[segnum];
668 /*
669 * In case we sleep in malloc(), mark the segment present but deleted
670 * so that noone else tries to create the same key.
671 */
672 shmseg->u.shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
673 shmseg->u.shm_perm.key = uap->key;
674 shmseg->u.shm_perm.seq = (shmseg->u.shm_perm.seq + 1) & 0x7fff;
675 shmid = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm);
676
677 /*
678 * We make sure that we have allocated a pager before we need
679 * to.
680 */
681 shm_object = vm_pager_allocate(shm_use_phys ? OBJT_PHYS : OBJT_SWAP,
682 0, size, VM_PROT_DEFAULT, 0, cred);
683 if (shm_object == NULL)
684 return (ENOMEM);
685 VM_OBJECT_LOCK(shm_object);
686 vm_object_clear_flag(shm_object, OBJ_ONEMAPPING);
687 vm_object_set_flag(shm_object, OBJ_NOSPLIT);
688 VM_OBJECT_UNLOCK(shm_object);
689
690 shmseg->object = shm_object;
691 shmseg->u.shm_perm.cuid = shmseg->u.shm_perm.uid = cred->cr_uid;
692 shmseg->u.shm_perm.cgid = shmseg->u.shm_perm.gid = cred->cr_gid;
693 shmseg->u.shm_perm.mode = (shmseg->u.shm_perm.mode & SHMSEG_WANTED) |
694 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
695 shmseg->u.shm_segsz = uap->size;
696 shmseg->u.shm_cpid = td->td_proc->p_pid;
697 shmseg->u.shm_lpid = shmseg->u.shm_nattch = 0;
698 shmseg->u.shm_atime = shmseg->u.shm_dtime = 0;
699 #ifdef MAC
700 mac_sysvshm_create(cred, shmseg);
701 #endif
702 shmseg->u.shm_ctime = time_second;
703 shm_committed += btoc(size);
704 shm_nused++;
705 if (shmseg->u.shm_perm.mode & SHMSEG_WANTED) {
706 /*
707 * Somebody else wanted this key while we were asleep. Wake
708 * them up now.
709 */
710 shmseg->u.shm_perm.mode &= ~SHMSEG_WANTED;
711 wakeup(shmseg);
712 }
713 td->td_retval[0] = shmid;
714 return (0);
715 }
716
717 #ifndef _SYS_SYSPROTO_H_
718 struct shmget_args {
719 key_t key;
720 size_t size;
721 int shmflg;
722 };
723 #endif
724 int
725 shmget(td, uap)
726 struct thread *td;
727 struct shmget_args *uap;
728 {
729 int segnum, mode;
730 int error;
731
732 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
733 return (ENOSYS);
734 mtx_lock(&Giant);
735 mode = uap->shmflg & ACCESSPERMS;
736 if (uap->key != IPC_PRIVATE) {
737 again:
738 segnum = shm_find_segment_by_key(uap->key);
739 if (segnum >= 0) {
740 error = shmget_existing(td, uap, mode, segnum);
741 if (error == EAGAIN)
742 goto again;
743 goto done2;
744 }
745 if ((uap->shmflg & IPC_CREAT) == 0) {
746 error = ENOENT;
747 goto done2;
748 }
749 }
750 error = shmget_allocate_segment(td, uap, mode);
751 done2:
752 mtx_unlock(&Giant);
753 return (error);
754 }
755
756 static void
757 shmfork_myhook(p1, p2)
758 struct proc *p1, *p2;
759 {
760 struct shmmap_state *shmmap_s;
761 size_t size;
762 int i;
763
764 mtx_lock(&Giant);
765 size = shminfo.shmseg * sizeof(struct shmmap_state);
766 shmmap_s = malloc(size, M_SHM, M_WAITOK);
767 bcopy(p1->p_vmspace->vm_shm, shmmap_s, size);
768 p2->p_vmspace->vm_shm = shmmap_s;
769 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
770 if (shmmap_s->shmid != -1)
771 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].u.shm_nattch++;
772 mtx_unlock(&Giant);
773 }
774
775 static void
776 shmexit_myhook(struct vmspace *vm)
777 {
778 struct shmmap_state *base, *shm;
779 int i;
780
781 if ((base = vm->vm_shm) != NULL) {
782 vm->vm_shm = NULL;
783 mtx_lock(&Giant);
784 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) {
785 if (shm->shmid != -1)
786 shm_delete_mapping(vm, shm);
787 }
788 mtx_unlock(&Giant);
789 free(base, M_SHM);
790 }
791 }
792
793 static void
794 shmrealloc(void)
795 {
796 int i;
797 struct shmid_kernel *newsegs;
798
799 if (shmalloced >= shminfo.shmmni)
800 return;
801
802 newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
803 if (newsegs == NULL)
804 return;
805 for (i = 0; i < shmalloced; i++)
806 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
807 for (; i < shminfo.shmmni; i++) {
808 shmsegs[i].u.shm_perm.mode = SHMSEG_FREE;
809 shmsegs[i].u.shm_perm.seq = 0;
810 #ifdef MAC
811 mac_sysvshm_init(&shmsegs[i]);
812 #endif
813 }
814 free(shmsegs, M_SHM);
815 shmsegs = newsegs;
816 shmalloced = shminfo.shmmni;
817 }
818
819 static void
820 shminit()
821 {
822 int i;
823
824 TUNABLE_ULONG_FETCH("kern.ipc.shmmaxpgs", &shminfo.shmall);
825 for (i = PAGE_SIZE; i > 0; i--) {
826 shminfo.shmmax = shminfo.shmall * i;
827 if (shminfo.shmmax >= shminfo.shmall)
828 break;
829 }
830 TUNABLE_ULONG_FETCH("kern.ipc.shmmin", &shminfo.shmmin);
831 TUNABLE_ULONG_FETCH("kern.ipc.shmmni", &shminfo.shmmni);
832 TUNABLE_ULONG_FETCH("kern.ipc.shmseg", &shminfo.shmseg);
833 TUNABLE_INT_FETCH("kern.ipc.shm_use_phys", &shm_use_phys);
834
835 shmalloced = shminfo.shmmni;
836 shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
837 if (shmsegs == NULL)
838 panic("cannot allocate initial memory for sysvshm");
839 for (i = 0; i < shmalloced; i++) {
840 shmsegs[i].u.shm_perm.mode = SHMSEG_FREE;
841 shmsegs[i].u.shm_perm.seq = 0;
842 #ifdef MAC
843 mac_sysvshm_init(&shmsegs[i]);
844 #endif
845 }
846 shm_last_free = 0;
847 shm_nused = 0;
848 shm_committed = 0;
849 shmexit_hook = &shmexit_myhook;
850 shmfork_hook = &shmfork_myhook;
851 }
852
853 static int
854 shmunload()
855 {
856 #ifdef MAC
857 int i;
858 #endif
859
860 if (shm_nused > 0)
861 return (EBUSY);
862
863 #ifdef MAC
864 for (i = 0; i < shmalloced; i++)
865 mac_sysvshm_destroy(&shmsegs[i]);
866 #endif
867 free(shmsegs, M_SHM);
868 shmexit_hook = NULL;
869 shmfork_hook = NULL;
870 return (0);
871 }
872
873 static int
874 sysctl_shmsegs(SYSCTL_HANDLER_ARGS)
875 {
876
877 return (SYSCTL_OUT(req, shmsegs, shmalloced * sizeof(shmsegs[0])));
878 }
879
880 #if defined(__i386__) && (defined(COMPAT_FREEBSD4) || defined(COMPAT_43))
881 struct oshmid_ds {
882 struct ipc_perm_old shm_perm; /* operation perms */
883 int shm_segsz; /* size of segment (bytes) */
884 u_short shm_cpid; /* pid, creator */
885 u_short shm_lpid; /* pid, last operation */
886 short shm_nattch; /* no. of current attaches */
887 time_t shm_atime; /* last attach time */
888 time_t shm_dtime; /* last detach time */
889 time_t shm_ctime; /* last change time */
890 void *shm_handle; /* internal handle for shm segment */
891 };
892
893 struct oshmctl_args {
894 int shmid;
895 int cmd;
896 struct oshmid_ds *ubuf;
897 };
898
899 static int
900 oshmctl(struct thread *td, struct oshmctl_args *uap)
901 {
902 #ifdef COMPAT_43
903 int error = 0;
904 struct shmid_kernel *shmseg;
905 struct oshmid_ds outbuf;
906
907 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
908 return (ENOSYS);
909 mtx_lock(&Giant);
910 shmseg = shm_find_segment_by_shmid(uap->shmid);
911 if (shmseg == NULL) {
912 error = EINVAL;
913 goto done2;
914 }
915 switch (uap->cmd) {
916 case IPC_STAT:
917 error = ipcperm(td, &shmseg->u.shm_perm, IPC_R);
918 if (error)
919 goto done2;
920 #ifdef MAC
921 error = mac_sysvshm_check_shmctl(td->td_ucred, shmseg, uap->cmd);
922 if (error != 0)
923 goto done2;
924 #endif
925 ipcperm_new2old(&shmseg->u.shm_perm, &outbuf.shm_perm);
926 outbuf.shm_segsz = shmseg->u.shm_segsz;
927 outbuf.shm_cpid = shmseg->u.shm_cpid;
928 outbuf.shm_lpid = shmseg->u.shm_lpid;
929 outbuf.shm_nattch = shmseg->u.shm_nattch;
930 outbuf.shm_atime = shmseg->u.shm_atime;
931 outbuf.shm_dtime = shmseg->u.shm_dtime;
932 outbuf.shm_ctime = shmseg->u.shm_ctime;
933 outbuf.shm_handle = shmseg->object;
934 error = copyout(&outbuf, uap->ubuf, sizeof(outbuf));
935 if (error)
936 goto done2;
937 break;
938 default:
939 error = freebsd7_shmctl(td, (struct freebsd7_shmctl_args *)uap);
940 break;
941 }
942 done2:
943 mtx_unlock(&Giant);
944 return (error);
945 #else
946 return (EINVAL);
947 #endif
948 }
949
950 /* XXX casting to (sy_call_t *) is bogus, as usual. */
951 static sy_call_t *shmcalls[] = {
952 (sy_call_t *)shmat, (sy_call_t *)oshmctl,
953 (sy_call_t *)shmdt, (sy_call_t *)shmget,
954 (sy_call_t *)freebsd7_shmctl
955 };
956
957 int
958 shmsys(td, uap)
959 struct thread *td;
960 /* XXX actually varargs. */
961 struct shmsys_args /* {
962 int which;
963 int a2;
964 int a3;
965 int a4;
966 } */ *uap;
967 {
968 int error;
969
970 if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
971 return (ENOSYS);
972 if (uap->which < 0 ||
973 uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
974 return (EINVAL);
975 mtx_lock(&Giant);
976 error = (*shmcalls[uap->which])(td, &uap->a2);
977 mtx_unlock(&Giant);
978 return (error);
979 }
980
981 SYSCALL_MODULE_HELPER(shmsys);
982 #endif /* i386 && (COMPAT_FREEBSD4 || COMPAT_43) */
983
984 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
985 defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
986
987 #define CP(src, dst, fld) do { (dst).fld = (src).fld; } while (0)
988
989
990 #ifndef _SYS_SYSPROTO_H_
991 struct freebsd7_shmctl_args {
992 int shmid;
993 int cmd;
994 struct shmid_ds_old *buf;
995 };
996 #endif
997 int
998 freebsd7_shmctl(td, uap)
999 struct thread *td;
1000 struct freebsd7_shmctl_args *uap;
1001 {
1002 int error = 0;
1003 struct shmid_ds_old old;
1004 struct shmid_ds buf;
1005 size_t bufsz;
1006
1007 /*
1008 * The only reason IPC_INFO, SHM_INFO, SHM_STAT exists is to support
1009 * Linux binaries. If we see the call come through the FreeBSD ABI,
1010 * return an error back to the user since we do not to support this.
1011 */
1012 if (uap->cmd == IPC_INFO || uap->cmd == SHM_INFO ||
1013 uap->cmd == SHM_STAT)
1014 return (EINVAL);
1015
1016 /* IPC_SET needs to copyin the buffer before calling kern_shmctl */
1017 if (uap->cmd == IPC_SET) {
1018 if ((error = copyin(uap->buf, &old, sizeof(old))))
1019 goto done;
1020 ipcperm_old2new(&old.shm_perm, &buf.shm_perm);
1021 CP(old, buf, shm_segsz);
1022 CP(old, buf, shm_lpid);
1023 CP(old, buf, shm_cpid);
1024 CP(old, buf, shm_nattch);
1025 CP(old, buf, shm_atime);
1026 CP(old, buf, shm_dtime);
1027 CP(old, buf, shm_ctime);
1028 }
1029
1030 error = kern_shmctl(td, uap->shmid, uap->cmd, (void *)&buf, &bufsz);
1031 if (error)
1032 goto done;
1033
1034 /* Cases in which we need to copyout */
1035 switch (uap->cmd) {
1036 case IPC_STAT:
1037 ipcperm_new2old(&buf.shm_perm, &old.shm_perm);
1038 if (buf.shm_segsz > INT_MAX)
1039 old.shm_segsz = INT_MAX;
1040 else
1041 CP(buf, old, shm_segsz);
1042 CP(buf, old, shm_lpid);
1043 CP(buf, old, shm_cpid);
1044 if (buf.shm_nattch > SHRT_MAX)
1045 old.shm_nattch = SHRT_MAX;
1046 else
1047 CP(buf, old, shm_nattch);
1048 CP(buf, old, shm_atime);
1049 CP(buf, old, shm_dtime);
1050 CP(buf, old, shm_ctime);
1051 old.shm_internal = NULL;
1052 error = copyout(&old, uap->buf, sizeof(old));
1053 break;
1054 }
1055
1056 done:
1057 if (error) {
1058 /* Invalidate the return value */
1059 td->td_retval[0] = -1;
1060 }
1061 return (error);
1062 }
1063
1064 SYSCALL_MODULE_HELPER(freebsd7_shmctl);
1065
1066 #undef CP
1067
1068 #endif /* COMPAT_FREEBSD4 || COMPAT_FREEBSD5 || COMPAT_FREEBSD6 ||
1069 COMPAT_FREEBSD7 */
1070
1071 static int
1072 sysvshm_modload(struct module *module, int cmd, void *arg)
1073 {
1074 int error = 0;
1075
1076 switch (cmd) {
1077 case MOD_LOAD:
1078 shminit();
1079 break;
1080 case MOD_UNLOAD:
1081 error = shmunload();
1082 break;
1083 case MOD_SHUTDOWN:
1084 break;
1085 default:
1086 error = EINVAL;
1087 break;
1088 }
1089 return (error);
1090 }
1091
1092 static moduledata_t sysvshm_mod = {
1093 "sysvshm",
1094 &sysvshm_modload,
1095 NULL
1096 };
1097
1098 SYSCALL_MODULE_HELPER(shmat);
1099 SYSCALL_MODULE_HELPER(shmctl);
1100 SYSCALL_MODULE_HELPER(shmdt);
1101 SYSCALL_MODULE_HELPER(shmget);
1102
1103 DECLARE_MODULE(sysvshm, sysvshm_mod, SI_SUB_SYSV_SHM, SI_ORDER_FIRST);
1104 MODULE_VERSION(sysvshm, 1);
Cache object: 0726066a479b729e00db93934e3b1f60
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