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/6.1/sys/kern/sysv_shm.c 158179 2006-04-30 16:44:43Z cvs2svn $");
64
65 #include "opt_compat.h"
66 #include "opt_sysvipc.h"
67 #include "opt_mac.h"
68
69 #include <sys/param.h>
70 #include <sys/systm.h>
71 #include <sys/kernel.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 #include <sys/mac.h>
88
89 #include <vm/vm.h>
90 #include <vm/vm_param.h>
91 #include <vm/pmap.h>
92 #include <vm/vm_object.h>
93 #include <vm/vm_map.h>
94 #include <vm/vm_page.h>
95 #include <vm/vm_pager.h>
96
97 #ifdef MAC_DEBUG
98 #define MPRINTF(a) printf a
99 #else
100 #define MPRINTF(a)
101 #endif
102
103 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments");
104
105 struct oshmctl_args;
106 static int oshmctl(struct thread *td, struct oshmctl_args *uap);
107
108 static int shmget_allocate_segment(struct thread *td,
109 struct shmget_args *uap, int mode);
110 static int shmget_existing(struct thread *td, struct shmget_args *uap,
111 int mode, int segnum);
112
113 /* XXX casting to (sy_call_t *) is bogus, as usual. */
114 static sy_call_t *shmcalls[] = {
115 (sy_call_t *)shmat, (sy_call_t *)oshmctl,
116 (sy_call_t *)shmdt, (sy_call_t *)shmget,
117 (sy_call_t *)shmctl
118 };
119
120 #define SHMSEG_FREE 0x0200
121 #define SHMSEG_REMOVED 0x0400
122 #define SHMSEG_ALLOCATED 0x0800
123 #define SHMSEG_WANTED 0x1000
124
125 static int shm_last_free, shm_nused, shm_committed, shmalloced;
126 static struct shmid_kernel *shmsegs;
127
128 struct shmmap_state {
129 vm_offset_t va;
130 int shmid;
131 };
132
133 static void shm_deallocate_segment(struct shmid_kernel *);
134 static int shm_find_segment_by_key(key_t);
135 static struct shmid_kernel *shm_find_segment_by_shmid(int);
136 static struct shmid_kernel *shm_find_segment_by_shmidx(int);
137 static int shm_delete_mapping(struct vmspace *vm, struct shmmap_state *);
138 static void shmrealloc(void);
139 static void shminit(void);
140 static int sysvshm_modload(struct module *, int, void *);
141 static int shmunload(void);
142 static void shmexit_myhook(struct vmspace *vm);
143 static void shmfork_myhook(struct proc *p1, struct proc *p2);
144 static int sysctl_shmsegs(SYSCTL_HANDLER_ARGS);
145
146 /*
147 * Tuneable values.
148 */
149 #ifndef SHMMAXPGS
150 #define SHMMAXPGS 8192 /* Note: sysv shared memory is swap backed. */
151 #endif
152 #ifndef SHMMAX
153 #define SHMMAX (SHMMAXPGS*PAGE_SIZE)
154 #endif
155 #ifndef SHMMIN
156 #define SHMMIN 1
157 #endif
158 #ifndef SHMMNI
159 #define SHMMNI 192
160 #endif
161 #ifndef SHMSEG
162 #define SHMSEG 128
163 #endif
164 #ifndef SHMALL
165 #define SHMALL (SHMMAXPGS)
166 #endif
167
168 struct shminfo shminfo = {
169 SHMMAX,
170 SHMMIN,
171 SHMMNI,
172 SHMSEG,
173 SHMALL
174 };
175
176 static int shm_use_phys;
177 static int shm_allow_removed;
178
179 SYSCTL_DECL(_kern_ipc);
180 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0,
181 "Maximum shared memory segment size");
182 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0,
183 "Minimum shared memory segment size");
184 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RDTUN, &shminfo.shmmni, 0,
185 "Number of shared memory identifiers");
186 SYSCTL_INT(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RDTUN, &shminfo.shmseg, 0,
187 "Number of segments per process");
188 SYSCTL_INT(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0,
189 "Maximum number of pages available for shared memory");
190 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW,
191 &shm_use_phys, 0, "Enable/Disable locking of shared memory pages in core");
192 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_allow_removed, CTLFLAG_RW,
193 &shm_allow_removed, 0,
194 "Enable/Disable attachment to attached segments marked for removal");
195 SYSCTL_PROC(_kern_ipc, OID_AUTO, shmsegs, CTLFLAG_RD,
196 NULL, 0, sysctl_shmsegs, "",
197 "Current number of shared memory segments allocated");
198
199 static int
200 shm_find_segment_by_key(key)
201 key_t key;
202 {
203 int i;
204
205 for (i = 0; i < shmalloced; i++)
206 if ((shmsegs[i].u.shm_perm.mode & SHMSEG_ALLOCATED) &&
207 shmsegs[i].u.shm_perm.key == key)
208 return (i);
209 return (-1);
210 }
211
212 static struct shmid_kernel *
213 shm_find_segment_by_shmid(int shmid)
214 {
215 int segnum;
216 struct shmid_kernel *shmseg;
217
218 segnum = IPCID_TO_IX(shmid);
219 if (segnum < 0 || segnum >= shmalloced)
220 return (NULL);
221 shmseg = &shmsegs[segnum];
222 if ((shmseg->u.shm_perm.mode & SHMSEG_ALLOCATED) == 0 ||
223 (!shm_allow_removed &&
224 (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) != 0) ||
225 shmseg->u.shm_perm.seq != IPCID_TO_SEQ(shmid))
226 return (NULL);
227 return (shmseg);
228 }
229
230 static struct shmid_kernel *
231 shm_find_segment_by_shmidx(int segnum)
232 {
233 struct shmid_kernel *shmseg;
234
235 if (segnum < 0 || segnum >= shmalloced)
236 return (NULL);
237 shmseg = &shmsegs[segnum];
238 if ((shmseg->u.shm_perm.mode & SHMSEG_ALLOCATED) == 0 ||
239 (!shm_allow_removed &&
240 (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) != 0))
241 return (NULL);
242 return (shmseg);
243 }
244
245 static void
246 shm_deallocate_segment(shmseg)
247 struct shmid_kernel *shmseg;
248 {
249 size_t size;
250
251 GIANT_REQUIRED;
252
253 vm_object_deallocate(shmseg->u.shm_internal);
254 shmseg->u.shm_internal = NULL;
255 size = round_page(shmseg->u.shm_segsz);
256 shm_committed -= btoc(size);
257 shm_nused--;
258 shmseg->u.shm_perm.mode = SHMSEG_FREE;
259 #ifdef MAC
260 mac_cleanup_sysv_shm(shmseg);
261 #endif
262 }
263
264 static int
265 shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s)
266 {
267 struct shmid_kernel *shmseg;
268 int segnum, result;
269 size_t size;
270
271 GIANT_REQUIRED;
272
273 segnum = IPCID_TO_IX(shmmap_s->shmid);
274 shmseg = &shmsegs[segnum];
275 size = round_page(shmseg->u.shm_segsz);
276 result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size);
277 if (result != KERN_SUCCESS)
278 return (EINVAL);
279 shmmap_s->shmid = -1;
280 shmseg->u.shm_dtime = time_second;
281 if ((--shmseg->u.shm_nattch <= 0) &&
282 (shmseg->u.shm_perm.mode & SHMSEG_REMOVED)) {
283 shm_deallocate_segment(shmseg);
284 shm_last_free = segnum;
285 }
286 return (0);
287 }
288
289 #ifndef _SYS_SYSPROTO_H_
290 struct shmdt_args {
291 const void *shmaddr;
292 };
293 #endif
294
295 /*
296 * MPSAFE
297 */
298 int
299 shmdt(td, uap)
300 struct thread *td;
301 struct shmdt_args *uap;
302 {
303 struct proc *p = td->td_proc;
304 struct shmmap_state *shmmap_s;
305 #ifdef MAC
306 struct shmid_kernel *shmsegptr;
307 #endif
308 int i;
309 int error = 0;
310
311 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
312 return (ENOSYS);
313 mtx_lock(&Giant);
314 shmmap_s = p->p_vmspace->vm_shm;
315 if (shmmap_s == NULL) {
316 error = EINVAL;
317 goto done2;
318 }
319 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) {
320 if (shmmap_s->shmid != -1 &&
321 shmmap_s->va == (vm_offset_t)uap->shmaddr) {
322 break;
323 }
324 }
325 if (i == shminfo.shmseg) {
326 error = EINVAL;
327 goto done2;
328 }
329 #ifdef MAC
330 shmsegptr = &shmsegs[IPCID_TO_IX(shmmap_s->shmid)];
331 error = mac_check_sysv_shmdt(td->td_ucred, shmsegptr);
332 if (error != 0) {
333 MPRINTF(("mac_check_sysv_shmdt returned %d\n", error));
334 goto done2;
335 }
336 #endif
337 error = shm_delete_mapping(p->p_vmspace, shmmap_s);
338 done2:
339 mtx_unlock(&Giant);
340 return (error);
341 }
342
343 #ifndef _SYS_SYSPROTO_H_
344 struct shmat_args {
345 int shmid;
346 const void *shmaddr;
347 int shmflg;
348 };
349 #endif
350
351 /*
352 * MPSAFE
353 */
354 int
355 kern_shmat(td, shmid, shmaddr, shmflg)
356 struct thread *td;
357 int shmid;
358 const void *shmaddr;
359 int shmflg;
360 {
361 struct proc *p = td->td_proc;
362 int i, flags;
363 struct shmid_kernel *shmseg;
364 struct shmmap_state *shmmap_s = NULL;
365 vm_offset_t attach_va;
366 vm_prot_t prot;
367 vm_size_t size;
368 int rv;
369 int error = 0;
370
371 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
372 return (ENOSYS);
373 mtx_lock(&Giant);
374 shmmap_s = p->p_vmspace->vm_shm;
375 if (shmmap_s == NULL) {
376 size = shminfo.shmseg * sizeof(struct shmmap_state);
377 shmmap_s = malloc(size, M_SHM, M_WAITOK);
378 for (i = 0; i < shminfo.shmseg; i++)
379 shmmap_s[i].shmid = -1;
380 p->p_vmspace->vm_shm = shmmap_s;
381 }
382 shmseg = shm_find_segment_by_shmid(shmid);
383 if (shmseg == NULL) {
384 error = EINVAL;
385 goto done2;
386 }
387 error = ipcperm(td, &shmseg->u.shm_perm,
388 (shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
389 if (error)
390 goto done2;
391 #ifdef MAC
392 error = mac_check_sysv_shmat(td->td_ucred, shmseg, shmflg);
393 if (error != 0) {
394 MPRINTF(("mac_check_sysv_shmat returned %d\n", error));
395 goto done2;
396 }
397 #endif
398 for (i = 0; i < shminfo.shmseg; i++) {
399 if (shmmap_s->shmid == -1)
400 break;
401 shmmap_s++;
402 }
403 if (i >= shminfo.shmseg) {
404 error = EMFILE;
405 goto done2;
406 }
407 size = round_page(shmseg->u.shm_segsz);
408 #ifdef VM_PROT_READ_IS_EXEC
409 prot = VM_PROT_READ | VM_PROT_EXECUTE;
410 #else
411 prot = VM_PROT_READ;
412 #endif
413 if ((shmflg & SHM_RDONLY) == 0)
414 prot |= VM_PROT_WRITE;
415 flags = MAP_ANON | MAP_SHARED;
416 if (shmaddr) {
417 flags |= MAP_FIXED;
418 if (shmflg & SHM_RND) {
419 attach_va = (vm_offset_t)shmaddr & ~(SHMLBA-1);
420 } else if (((vm_offset_t)shmaddr & (SHMLBA-1)) == 0) {
421 attach_va = (vm_offset_t)shmaddr;
422 } else {
423 error = EINVAL;
424 goto done2;
425 }
426 } else {
427 /*
428 * This is just a hint to vm_map_find() about where to
429 * put it.
430 */
431 PROC_LOCK(p);
432 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_daddr +
433 lim_max(p, RLIMIT_DATA));
434 PROC_UNLOCK(p);
435 }
436
437 vm_object_reference(shmseg->u.shm_internal);
438 rv = vm_map_find(&p->p_vmspace->vm_map, shmseg->u.shm_internal,
439 0, &attach_va, size, (flags & MAP_FIXED)?0:1, prot, prot, 0);
440 if (rv != KERN_SUCCESS) {
441 vm_object_deallocate(shmseg->u.shm_internal);
442 error = ENOMEM;
443 goto done2;
444 }
445 vm_map_inherit(&p->p_vmspace->vm_map,
446 attach_va, attach_va + size, VM_INHERIT_SHARE);
447
448 shmmap_s->va = attach_va;
449 shmmap_s->shmid = shmid;
450 shmseg->u.shm_lpid = p->p_pid;
451 shmseg->u.shm_atime = time_second;
452 shmseg->u.shm_nattch++;
453 td->td_retval[0] = attach_va;
454 done2:
455 mtx_unlock(&Giant);
456 return (error);
457 }
458
459 int
460 shmat(td, uap)
461 struct thread *td;
462 struct shmat_args *uap;
463 {
464 return kern_shmat(td, uap->shmid, uap->shmaddr, uap->shmflg);
465 }
466
467 struct oshmid_ds {
468 struct ipc_perm shm_perm; /* operation perms */
469 int shm_segsz; /* size of segment (bytes) */
470 u_short shm_cpid; /* pid, creator */
471 u_short shm_lpid; /* pid, last operation */
472 short shm_nattch; /* no. of current attaches */
473 time_t shm_atime; /* last attach time */
474 time_t shm_dtime; /* last detach time */
475 time_t shm_ctime; /* last change time */
476 void *shm_handle; /* internal handle for shm segment */
477 };
478
479 struct oshmctl_args {
480 int shmid;
481 int cmd;
482 struct oshmid_ds *ubuf;
483 };
484
485 /*
486 * MPSAFE
487 */
488 static int
489 oshmctl(td, uap)
490 struct thread *td;
491 struct oshmctl_args *uap;
492 {
493 #ifdef COMPAT_43
494 int error = 0;
495 struct shmid_kernel *shmseg;
496 struct oshmid_ds outbuf;
497
498 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
499 return (ENOSYS);
500 mtx_lock(&Giant);
501 shmseg = shm_find_segment_by_shmid(uap->shmid);
502 if (shmseg == NULL) {
503 error = EINVAL;
504 goto done2;
505 }
506 switch (uap->cmd) {
507 case IPC_STAT:
508 error = ipcperm(td, &shmseg->u.shm_perm, IPC_R);
509 if (error)
510 goto done2;
511 #ifdef MAC
512 error = mac_check_sysv_shmctl(td->td_ucred, shmseg, uap->cmd);
513 if (error != 0) {
514 MPRINTF(("mac_check_sysv_shmctl returned %d\n",
515 error));
516 goto done2;
517 }
518 #endif
519 outbuf.shm_perm = shmseg->u.shm_perm;
520 outbuf.shm_segsz = shmseg->u.shm_segsz;
521 outbuf.shm_cpid = shmseg->u.shm_cpid;
522 outbuf.shm_lpid = shmseg->u.shm_lpid;
523 outbuf.shm_nattch = shmseg->u.shm_nattch;
524 outbuf.shm_atime = shmseg->u.shm_atime;
525 outbuf.shm_dtime = shmseg->u.shm_dtime;
526 outbuf.shm_ctime = shmseg->u.shm_ctime;
527 outbuf.shm_handle = shmseg->u.shm_internal;
528 error = copyout(&outbuf, uap->ubuf, sizeof(outbuf));
529 if (error)
530 goto done2;
531 break;
532 default:
533 error = shmctl(td, (struct shmctl_args *)uap);
534 break;
535 }
536 done2:
537 mtx_unlock(&Giant);
538 return (error);
539 #else
540 return (EINVAL);
541 #endif
542 }
543
544 #ifndef _SYS_SYSPROTO_H_
545 struct shmctl_args {
546 int shmid;
547 int cmd;
548 struct shmid_ds *buf;
549 };
550 #endif
551
552 /*
553 * MPSAFE
554 */
555 int
556 kern_shmctl(td, shmid, cmd, buf, bufsz)
557 struct thread *td;
558 int shmid;
559 int cmd;
560 void *buf;
561 size_t *bufsz;
562 {
563 int error = 0;
564 struct shmid_kernel *shmseg;
565
566 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
567 return (ENOSYS);
568
569 mtx_lock(&Giant);
570 switch (cmd) {
571 case IPC_INFO:
572 memcpy(buf, &shminfo, sizeof(shminfo));
573 if (bufsz)
574 *bufsz = sizeof(shminfo);
575 td->td_retval[0] = shmalloced;
576 goto done2;
577 case SHM_INFO: {
578 struct shm_info shm_info;
579 shm_info.used_ids = shm_nused;
580 shm_info.shm_rss = 0; /*XXX where to get from ? */
581 shm_info.shm_tot = 0; /*XXX where to get from ? */
582 shm_info.shm_swp = 0; /*XXX where to get from ? */
583 shm_info.swap_attempts = 0; /*XXX where to get from ? */
584 shm_info.swap_successes = 0; /*XXX where to get from ? */
585 memcpy(buf, &shm_info, sizeof(shm_info));
586 if (bufsz)
587 *bufsz = sizeof(shm_info);
588 td->td_retval[0] = shmalloced;
589 goto done2;
590 }
591 }
592 if (cmd == SHM_STAT)
593 shmseg = shm_find_segment_by_shmidx(shmid);
594 else
595 shmseg = shm_find_segment_by_shmid(shmid);
596 if (shmseg == NULL) {
597 error = EINVAL;
598 goto done2;
599 }
600 #ifdef MAC
601 error = mac_check_sysv_shmctl(td->td_ucred, shmseg, cmd);
602 if (error != 0) {
603 MPRINTF(("mac_check_sysv_shmctl returned %d\n", error));
604 goto done2;
605 }
606 #endif
607 switch (cmd) {
608 case SHM_STAT:
609 case IPC_STAT:
610 error = ipcperm(td, &shmseg->u.shm_perm, IPC_R);
611 if (error)
612 goto done2;
613 memcpy(buf, &shmseg->u, sizeof(struct shmid_ds));
614 if (bufsz)
615 *bufsz = sizeof(struct shmid_ds);
616 if (cmd == SHM_STAT)
617 td->td_retval[0] = IXSEQ_TO_IPCID(shmid, shmseg->u.shm_perm);
618 break;
619 case IPC_SET: {
620 struct shmid_ds *shmid;
621
622 shmid = (struct shmid_ds *)buf;
623 error = ipcperm(td, &shmseg->u.shm_perm, IPC_M);
624 if (error)
625 goto done2;
626 shmseg->u.shm_perm.uid = shmid->shm_perm.uid;
627 shmseg->u.shm_perm.gid = shmid->shm_perm.gid;
628 shmseg->u.shm_perm.mode =
629 (shmseg->u.shm_perm.mode & ~ACCESSPERMS) |
630 (shmid->shm_perm.mode & ACCESSPERMS);
631 shmseg->u.shm_ctime = time_second;
632 break;
633 }
634 case IPC_RMID:
635 error = ipcperm(td, &shmseg->u.shm_perm, IPC_M);
636 if (error)
637 goto done2;
638 shmseg->u.shm_perm.key = IPC_PRIVATE;
639 shmseg->u.shm_perm.mode |= SHMSEG_REMOVED;
640 if (shmseg->u.shm_nattch <= 0) {
641 shm_deallocate_segment(shmseg);
642 shm_last_free = IPCID_TO_IX(shmid);
643 }
644 break;
645 #if 0
646 case SHM_LOCK:
647 case SHM_UNLOCK:
648 #endif
649 default:
650 error = EINVAL;
651 break;
652 }
653 done2:
654 mtx_unlock(&Giant);
655 return (error);
656 }
657
658 int
659 shmctl(td, uap)
660 struct thread *td;
661 struct shmctl_args *uap;
662 {
663 int error = 0;
664 struct shmid_ds buf;
665 size_t bufsz;
666
667 /* IPC_SET needs to copyin the buffer before calling kern_shmctl */
668 if (uap->cmd == IPC_SET) {
669 if ((error = copyin(uap->buf, &buf, sizeof(struct shmid_ds))))
670 goto done;
671 }
672
673 error = kern_shmctl(td, uap->shmid, uap->cmd, (void *)&buf, &bufsz);
674 if (error)
675 goto done;
676
677 /* Cases in which we need to copyout */
678 switch (uap->cmd) {
679 case IPC_INFO:
680 case SHM_INFO:
681 case SHM_STAT:
682 case IPC_STAT:
683 error = copyout(&buf, uap->buf, bufsz);
684 break;
685 }
686
687 done:
688 if (error) {
689 /* Invalidate the return value */
690 td->td_retval[0] = -1;
691 }
692 return (error);
693 }
694
695
696 #ifndef _SYS_SYSPROTO_H_
697 struct shmget_args {
698 key_t key;
699 size_t size;
700 int shmflg;
701 };
702 #endif
703
704 static int
705 shmget_existing(td, uap, mode, segnum)
706 struct thread *td;
707 struct shmget_args *uap;
708 int mode;
709 int segnum;
710 {
711 struct shmid_kernel *shmseg;
712 int error;
713
714 shmseg = &shmsegs[segnum];
715 if (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) {
716 /*
717 * This segment is in the process of being allocated. Wait
718 * until it's done, and look the key up again (in case the
719 * allocation failed or it was freed).
720 */
721 shmseg->u.shm_perm.mode |= SHMSEG_WANTED;
722 error = tsleep(shmseg, PLOCK | PCATCH, "shmget", 0);
723 if (error)
724 return (error);
725 return (EAGAIN);
726 }
727 if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
728 return (EEXIST);
729 error = ipcperm(td, &shmseg->u.shm_perm, mode);
730 #ifdef MAC
731 error = mac_check_sysv_shmget(td->td_ucred, shmseg, uap->shmflg);
732 if (error != 0)
733 MPRINTF(("mac_check_sysv_shmget returned %d\n", error));
734 #endif
735 if (error)
736 return (error);
737 if (uap->size && uap->size > shmseg->u.shm_segsz)
738 return (EINVAL);
739 td->td_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm);
740 return (0);
741 }
742
743 static int
744 shmget_allocate_segment(td, uap, mode)
745 struct thread *td;
746 struct shmget_args *uap;
747 int mode;
748 {
749 int i, segnum, shmid, size;
750 struct ucred *cred = td->td_ucred;
751 struct shmid_kernel *shmseg;
752 vm_object_t shm_object;
753
754 GIANT_REQUIRED;
755
756 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
757 return (EINVAL);
758 if (shm_nused >= shminfo.shmmni) /* Any shmids left? */
759 return (ENOSPC);
760 size = round_page(uap->size);
761 if (shm_committed + btoc(size) > shminfo.shmall)
762 return (ENOMEM);
763 if (shm_last_free < 0) {
764 shmrealloc(); /* Maybe expand the shmsegs[] array. */
765 for (i = 0; i < shmalloced; i++)
766 if (shmsegs[i].u.shm_perm.mode & SHMSEG_FREE)
767 break;
768 if (i == shmalloced)
769 return (ENOSPC);
770 segnum = i;
771 } else {
772 segnum = shm_last_free;
773 shm_last_free = -1;
774 }
775 shmseg = &shmsegs[segnum];
776 /*
777 * In case we sleep in malloc(), mark the segment present but deleted
778 * so that noone else tries to create the same key.
779 */
780 shmseg->u.shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
781 shmseg->u.shm_perm.key = uap->key;
782 shmseg->u.shm_perm.seq = (shmseg->u.shm_perm.seq + 1) & 0x7fff;
783 shmid = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm);
784
785 /*
786 * We make sure that we have allocated a pager before we need
787 * to.
788 */
789 if (shm_use_phys) {
790 shm_object =
791 vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0);
792 } else {
793 shm_object =
794 vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0);
795 }
796 VM_OBJECT_LOCK(shm_object);
797 vm_object_clear_flag(shm_object, OBJ_ONEMAPPING);
798 vm_object_set_flag(shm_object, OBJ_NOSPLIT);
799 VM_OBJECT_UNLOCK(shm_object);
800
801 shmseg->u.shm_internal = shm_object;
802 shmseg->u.shm_perm.cuid = shmseg->u.shm_perm.uid = cred->cr_uid;
803 shmseg->u.shm_perm.cgid = shmseg->u.shm_perm.gid = cred->cr_gid;
804 shmseg->u.shm_perm.mode = (shmseg->u.shm_perm.mode & SHMSEG_WANTED) |
805 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
806 shmseg->u.shm_segsz = uap->size;
807 shmseg->u.shm_cpid = td->td_proc->p_pid;
808 shmseg->u.shm_lpid = shmseg->u.shm_nattch = 0;
809 shmseg->u.shm_atime = shmseg->u.shm_dtime = 0;
810 #ifdef MAC
811 mac_create_sysv_shm(cred, shmseg);
812 #endif
813 shmseg->u.shm_ctime = time_second;
814 shm_committed += btoc(size);
815 shm_nused++;
816 if (shmseg->u.shm_perm.mode & SHMSEG_WANTED) {
817 /*
818 * Somebody else wanted this key while we were asleep. Wake
819 * them up now.
820 */
821 shmseg->u.shm_perm.mode &= ~SHMSEG_WANTED;
822 wakeup(shmseg);
823 }
824 td->td_retval[0] = shmid;
825 return (0);
826 }
827
828 /*
829 * MPSAFE
830 */
831 int
832 shmget(td, uap)
833 struct thread *td;
834 struct shmget_args *uap;
835 {
836 int segnum, mode;
837 int error;
838
839 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
840 return (ENOSYS);
841 mtx_lock(&Giant);
842 mode = uap->shmflg & ACCESSPERMS;
843 if (uap->key != IPC_PRIVATE) {
844 again:
845 segnum = shm_find_segment_by_key(uap->key);
846 if (segnum >= 0) {
847 error = shmget_existing(td, uap, mode, segnum);
848 if (error == EAGAIN)
849 goto again;
850 goto done2;
851 }
852 if ((uap->shmflg & IPC_CREAT) == 0) {
853 error = ENOENT;
854 goto done2;
855 }
856 }
857 error = shmget_allocate_segment(td, uap, mode);
858 done2:
859 mtx_unlock(&Giant);
860 return (error);
861 }
862
863 /*
864 * MPSAFE
865 */
866 int
867 shmsys(td, uap)
868 struct thread *td;
869 /* XXX actually varargs. */
870 struct shmsys_args /* {
871 int which;
872 int a2;
873 int a3;
874 int a4;
875 } */ *uap;
876 {
877 int error;
878
879 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
880 return (ENOSYS);
881 if (uap->which < 0 ||
882 uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
883 return (EINVAL);
884 mtx_lock(&Giant);
885 error = (*shmcalls[uap->which])(td, &uap->a2);
886 mtx_unlock(&Giant);
887 return (error);
888 }
889
890 static void
891 shmfork_myhook(p1, p2)
892 struct proc *p1, *p2;
893 {
894 struct shmmap_state *shmmap_s;
895 size_t size;
896 int i;
897
898 mtx_lock(&Giant);
899 size = shminfo.shmseg * sizeof(struct shmmap_state);
900 shmmap_s = malloc(size, M_SHM, M_WAITOK);
901 bcopy(p1->p_vmspace->vm_shm, shmmap_s, size);
902 p2->p_vmspace->vm_shm = shmmap_s;
903 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
904 if (shmmap_s->shmid != -1)
905 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].u.shm_nattch++;
906 mtx_unlock(&Giant);
907 }
908
909 static void
910 shmexit_myhook(struct vmspace *vm)
911 {
912 struct shmmap_state *base, *shm;
913 int i;
914
915 if ((base = vm->vm_shm) != NULL) {
916 vm->vm_shm = NULL;
917 mtx_lock(&Giant);
918 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) {
919 if (shm->shmid != -1)
920 shm_delete_mapping(vm, shm);
921 }
922 mtx_unlock(&Giant);
923 free(base, M_SHM);
924 }
925 }
926
927 static void
928 shmrealloc(void)
929 {
930 int i;
931 struct shmid_kernel *newsegs;
932
933 if (shmalloced >= shminfo.shmmni)
934 return;
935
936 newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
937 if (newsegs == NULL)
938 return;
939 for (i = 0; i < shmalloced; i++)
940 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
941 for (; i < shminfo.shmmni; i++) {
942 shmsegs[i].u.shm_perm.mode = SHMSEG_FREE;
943 shmsegs[i].u.shm_perm.seq = 0;
944 #ifdef MAC
945 mac_init_sysv_shm(&shmsegs[i]);
946 #endif
947 }
948 free(shmsegs, M_SHM);
949 shmsegs = newsegs;
950 shmalloced = shminfo.shmmni;
951 }
952
953 static void
954 shminit()
955 {
956 int i;
957
958 TUNABLE_INT_FETCH("kern.ipc.shmmaxpgs", &shminfo.shmall);
959 for (i = PAGE_SIZE; i > 0; i--) {
960 shminfo.shmmax = shminfo.shmall * i;
961 if (shminfo.shmmax >= shminfo.shmall)
962 break;
963 }
964 TUNABLE_INT_FETCH("kern.ipc.shmmin", &shminfo.shmmin);
965 TUNABLE_INT_FETCH("kern.ipc.shmmni", &shminfo.shmmni);
966 TUNABLE_INT_FETCH("kern.ipc.shmseg", &shminfo.shmseg);
967 TUNABLE_INT_FETCH("kern.ipc.shm_use_phys", &shm_use_phys);
968
969 shmalloced = shminfo.shmmni;
970 shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
971 if (shmsegs == NULL)
972 panic("cannot allocate initial memory for sysvshm");
973 for (i = 0; i < shmalloced; i++) {
974 shmsegs[i].u.shm_perm.mode = SHMSEG_FREE;
975 shmsegs[i].u.shm_perm.seq = 0;
976 #ifdef MAC
977 mac_init_sysv_shm(&shmsegs[i]);
978 #endif
979 }
980 shm_last_free = 0;
981 shm_nused = 0;
982 shm_committed = 0;
983 shmexit_hook = &shmexit_myhook;
984 shmfork_hook = &shmfork_myhook;
985 }
986
987 static int
988 shmunload()
989 {
990 #ifdef MAC
991 int i;
992 #endif
993
994 if (shm_nused > 0)
995 return (EBUSY);
996
997 #ifdef MAC
998 for (i = 0; i < shmalloced; i++)
999 mac_destroy_sysv_shm(&shmsegs[i]);
1000 #endif
1001 free(shmsegs, M_SHM);
1002 shmexit_hook = NULL;
1003 shmfork_hook = NULL;
1004 return (0);
1005 }
1006
1007 static int
1008 sysctl_shmsegs(SYSCTL_HANDLER_ARGS)
1009 {
1010
1011 return (SYSCTL_OUT(req, shmsegs, shmalloced * sizeof(shmsegs[0])));
1012 }
1013
1014 static int
1015 sysvshm_modload(struct module *module, int cmd, void *arg)
1016 {
1017 int error = 0;
1018
1019 switch (cmd) {
1020 case MOD_LOAD:
1021 shminit();
1022 break;
1023 case MOD_UNLOAD:
1024 error = shmunload();
1025 break;
1026 case MOD_SHUTDOWN:
1027 break;
1028 default:
1029 error = EINVAL;
1030 break;
1031 }
1032 return (error);
1033 }
1034
1035 static moduledata_t sysvshm_mod = {
1036 "sysvshm",
1037 &sysvshm_modload,
1038 NULL
1039 };
1040
1041 SYSCALL_MODULE_HELPER(shmsys);
1042 SYSCALL_MODULE_HELPER(shmat);
1043 SYSCALL_MODULE_HELPER(shmctl);
1044 SYSCALL_MODULE_HELPER(shmdt);
1045 SYSCALL_MODULE_HELPER(shmget);
1046
1047 DECLARE_MODULE(sysvshm, sysvshm_mod,
1048 SI_SUB_SYSV_SHM, SI_ORDER_FIRST);
1049 MODULE_VERSION(sysvshm, 1);
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