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#include <sys/cdefs.h>
33__FBSDID("$FreeBSD: head/sys/kern/sysv_shm.c 116182 2003-06-11 00:56:59Z obrien $");
34
35#include "opt_compat.h"
36#include "opt_sysvipc.h"
37
38#include <sys/param.h>
39#include <sys/systm.h>
40#include <sys/kernel.h>
41#include <sys/lock.h>
42#include <sys/sysctl.h>
43#include <sys/shm.h>
44#include <sys/proc.h>
45#include <sys/malloc.h>
46#include <sys/mman.h>
47#include <sys/mutex.h>
48#include <sys/stat.h>
49#include <sys/syscall.h>
50#include <sys/syscallsubr.h>
51#include <sys/sysent.h>
52#include <sys/sysproto.h>
53#include <sys/jail.h>
54
55#include <vm/vm.h>
56#include <vm/vm_param.h>
57#include <vm/pmap.h>
58#include <vm/vm_object.h>
59#include <vm/vm_map.h>
60#include <vm/vm_page.h>
61#include <vm/vm_pager.h>
62
63static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments");
64
65struct oshmctl_args;
66static int oshmctl(struct thread *td, struct oshmctl_args *uap);
67
68static int shmget_allocate_segment(struct thread *td,
69 struct shmget_args *uap, int mode);
70static int shmget_existing(struct thread *td, struct shmget_args *uap,
71 int mode, int segnum);
72
73/* XXX casting to (sy_call_t *) is bogus, as usual. */
74static sy_call_t *shmcalls[] = {
75 (sy_call_t *)shmat, (sy_call_t *)oshmctl,
76 (sy_call_t *)shmdt, (sy_call_t *)shmget,
77 (sy_call_t *)shmctl
78};
79
80#define SHMSEG_FREE 0x0200
81#define SHMSEG_REMOVED 0x0400
82#define SHMSEG_ALLOCATED 0x0800
83#define SHMSEG_WANTED 0x1000
84
85static int shm_last_free, shm_nused, shm_committed, shmalloced;
86static struct shmid_ds *shmsegs;
87
88struct shm_handle {
89 /* vm_offset_t kva; */
90 vm_object_t shm_object;
91};
92
93struct shmmap_state {
94 vm_offset_t va;
95 int shmid;
96};
97
98static void shm_deallocate_segment(struct shmid_ds *);
99static int shm_find_segment_by_key(key_t);
100static struct shmid_ds *shm_find_segment_by_shmid(int, int);
101static struct shmid_ds *shm_find_segment_by_shmidx(int, int);
102static int shm_delete_mapping(struct vmspace *vm, struct shmmap_state *);
103static void shmrealloc(void);
104static void shminit(void);
105static int sysvshm_modload(struct module *, int, void *);
106static int shmunload(void);
107static void shmexit_myhook(struct vmspace *vm);
108static void shmfork_myhook(struct proc *p1, struct proc *p2);
109static int sysctl_shmsegs(SYSCTL_HANDLER_ARGS);
110
111/*
112 * Tuneable values.
113 */
114#ifndef SHMMAXPGS
115#define SHMMAXPGS 8192 /* Note: sysv shared memory is swap backed. */
116#endif
117#ifndef SHMMAX
118#define SHMMAX (SHMMAXPGS*PAGE_SIZE)
119#endif
120#ifndef SHMMIN
121#define SHMMIN 1
122#endif
123#ifndef SHMMNI
124#define SHMMNI 192
125#endif
126#ifndef SHMSEG
127#define SHMSEG 128
128#endif
129#ifndef SHMALL
130#define SHMALL (SHMMAXPGS)
131#endif
132
133struct shminfo shminfo = {
134 SHMMAX,
135 SHMMIN,
136 SHMMNI,
137 SHMSEG,
138 SHMALL
139};
140
141static int shm_use_phys;
142
143SYSCTL_DECL(_kern_ipc);
144SYSCTL_INT(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, "");
145SYSCTL_INT(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, "");
146SYSCTL_INT(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0, "");
147SYSCTL_INT(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RD, &shminfo.shmseg, 0, "");
148SYSCTL_INT(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, "");
149SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW,
150 &shm_use_phys, 0, "");
151SYSCTL_PROC(_kern_ipc, OID_AUTO, shmsegs, CTLFLAG_RD,
152 NULL, 0, sysctl_shmsegs, "", "");
153
154static int
155shm_find_segment_by_key(key)
156 key_t key;
157{
158 int i;
159
160 for (i = 0; i < shmalloced; i++)
161 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) &&
162 shmsegs[i].shm_perm.key == key)
163 return (i);
164 return (-1);
165}
166
167static struct shmid_ds *
168shm_find_segment_by_shmid(int shmid, int wantrem)
169{
170 int segnum;
171 struct shmid_ds *shmseg;
172
173 segnum = IPCID_TO_IX(shmid);
174 if (segnum < 0 || segnum >= shmalloced)
175 return (NULL);
176 shmseg = &shmsegs[segnum];
177 if (!((shmseg->shm_perm.mode & SHMSEG_ALLOCATED) ||
178 (wantrem && !(shmseg->shm_perm.mode & SHMSEG_REMOVED))) ||
179 shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid))
180 return (NULL);
181 return (shmseg);
182}
183
184static struct shmid_ds *
185shm_find_segment_by_shmidx(int segnum, int wantrem)
186{
187 struct shmid_ds *shmseg;
188
189 if (segnum < 0 || segnum >= shmalloced)
190 return (NULL);
191 shmseg = &shmsegs[segnum];
192 if (!((shmseg->shm_perm.mode & SHMSEG_ALLOCATED) ||
193 (wantrem && !(shmseg->shm_perm.mode & SHMSEG_REMOVED))))
194 return (NULL);
195 return (shmseg);
196}
197
198static void
199shm_deallocate_segment(shmseg)
200 struct shmid_ds *shmseg;
201{
202 struct shm_handle *shm_handle;
203 size_t size;
204
205 GIANT_REQUIRED;
206
207 shm_handle = shmseg->shm_internal;
208 vm_object_deallocate(shm_handle->shm_object);
209 free(shm_handle, M_SHM);
210 shmseg->shm_internal = NULL;
211 size = round_page(shmseg->shm_segsz);
212 shm_committed -= btoc(size);
213 shm_nused--;
214 shmseg->shm_perm.mode = SHMSEG_FREE;
215}
216
217static int
218shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s)
219{
220 struct shmid_ds *shmseg;
221 int segnum, result;
222 size_t size;
223
224 GIANT_REQUIRED;
225
226 segnum = IPCID_TO_IX(shmmap_s->shmid);
227 shmseg = &shmsegs[segnum];
228 size = round_page(shmseg->shm_segsz);
229 result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size);
230 if (result != KERN_SUCCESS)
231 return (EINVAL);
232 shmmap_s->shmid = -1;
233 shmseg->shm_dtime = time_second;
234 if ((--shmseg->shm_nattch <= 0) &&
235 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) {
236 shm_deallocate_segment(shmseg);
237 shm_last_free = segnum;
238 }
239 return (0);
240}
241
242#ifndef _SYS_SYSPROTO_H_
243struct shmdt_args {
244 const void *shmaddr;
245};
246#endif
247
248/*
249 * MPSAFE
250 */
251int
252shmdt(td, uap)
253 struct thread *td;
254 struct shmdt_args *uap;
255{
256 struct proc *p = td->td_proc;
257 struct shmmap_state *shmmap_s;
258 int i;
259 int error = 0;
260
261 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
262 return (ENOSYS);
263 mtx_lock(&Giant);
264 shmmap_s = p->p_vmspace->vm_shm;
265 if (shmmap_s == NULL) {
266 error = EINVAL;
267 goto done2;
268 }
269 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) {
270 if (shmmap_s->shmid != -1 &&
271 shmmap_s->va == (vm_offset_t)uap->shmaddr) {
272 break;
273 }
274 }
275 if (i == shminfo.shmseg) {
276 error = EINVAL;
277 goto done2;
278 }
279 error = shm_delete_mapping(p->p_vmspace, shmmap_s);
280done2:
281 mtx_unlock(&Giant);
282 return (error);
283}
284
285#ifndef _SYS_SYSPROTO_H_
286struct shmat_args {
287 int shmid;
288 const void *shmaddr;
289 int shmflg;
290};
291#endif
292
293/*
294 * MPSAFE
295 */
296int
297kern_shmat(td, shmid, shmaddr, shmflg, wantrem)
298 struct thread *td;
299 int shmid;
300 const void *shmaddr;
301 int shmflg;
302 int wantrem;
303{
304 struct proc *p = td->td_proc;
305 int i, flags;
306 struct shmid_ds *shmseg;
307 struct shmmap_state *shmmap_s = NULL;
308 struct shm_handle *shm_handle;
309 vm_offset_t attach_va;
310 vm_prot_t prot;
311 vm_size_t size;
312 int rv;
313 int error = 0;
314
315 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
316 return (ENOSYS);
317 mtx_lock(&Giant);
318 shmmap_s = p->p_vmspace->vm_shm;
319 if (shmmap_s == NULL) {
320 size = shminfo.shmseg * sizeof(struct shmmap_state);
321 shmmap_s = malloc(size, M_SHM, M_WAITOK);
322 for (i = 0; i < shminfo.shmseg; i++)
323 shmmap_s[i].shmid = -1;
324 p->p_vmspace->vm_shm = shmmap_s;
325 }
326 shmseg = shm_find_segment_by_shmid(shmid, wantrem);
327 if (shmseg == NULL) {
328 error = EINVAL;
329 goto done2;
330 }
331 error = ipcperm(td, &shmseg->shm_perm,
332 (shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
333 if (error)
334 goto done2;
335 for (i = 0; i < shminfo.shmseg; i++) {
336 if (shmmap_s->shmid == -1)
337 break;
338 shmmap_s++;
339 }
340 if (i >= shminfo.shmseg) {
341 error = EMFILE;
342 goto done2;
343 }
344 size = round_page(shmseg->shm_segsz);
345#ifdef VM_PROT_READ_IS_EXEC
346 prot = VM_PROT_READ | VM_PROT_EXECUTE;
347#else
348 prot = VM_PROT_READ;
349#endif
350 if ((shmflg & SHM_RDONLY) == 0)
351 prot |= VM_PROT_WRITE;
352 flags = MAP_ANON | MAP_SHARED;
353 if (shmaddr) {
354 flags |= MAP_FIXED;
355 if (shmflg & SHM_RND) {
356 attach_va = (vm_offset_t)shmaddr & ~(SHMLBA-1);
357 } else if (((vm_offset_t)shmaddr & (SHMLBA-1)) == 0) {
358 attach_va = (vm_offset_t)shmaddr;
359 } else {
360 error = EINVAL;
361 goto done2;
362 }
363 } else {
364 /*
365 * This is just a hint to vm_map_find() about where to
366 * put it.
367 */
368 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr
369 + maxtsiz + maxdsiz);
370 }
371
372 shm_handle = shmseg->shm_internal;
373 vm_object_reference(shm_handle->shm_object);
374 rv = vm_map_find(&p->p_vmspace->vm_map, shm_handle->shm_object,
375 0, &attach_va, size, (flags & MAP_FIXED)?0:1, prot, prot, 0);
376 if (rv != KERN_SUCCESS) {
377 error = ENOMEM;
378 goto done2;
379 }
380 vm_map_inherit(&p->p_vmspace->vm_map,
381 attach_va, attach_va + size, VM_INHERIT_SHARE);
382
383 shmmap_s->va = attach_va;
384 shmmap_s->shmid = shmid;
385 shmseg->shm_lpid = p->p_pid;
386 shmseg->shm_atime = time_second;
387 shmseg->shm_nattch++;
388 td->td_retval[0] = attach_va;
389done2:
390 mtx_unlock(&Giant);
391 return (error);
392}
393
394int
395shmat(td, uap)
396 struct thread *td;
397 struct shmat_args *uap;
398{
399 return kern_shmat(td, uap->shmid, uap->shmaddr, uap->shmflg, 0);
400}
401
402struct oshmid_ds {
403 struct ipc_perm shm_perm; /* operation perms */
404 int shm_segsz; /* size of segment (bytes) */
405 ushort shm_cpid; /* pid, creator */
406 ushort shm_lpid; /* pid, last operation */
407 short shm_nattch; /* no. of current attaches */
408 time_t shm_atime; /* last attach time */
409 time_t shm_dtime; /* last detach time */
410 time_t shm_ctime; /* last change time */
411 void *shm_handle; /* internal handle for shm segment */
412};
413
414struct oshmctl_args {
415 int shmid;
416 int cmd;
417 struct oshmid_ds *ubuf;
418};
419
420/*
421 * MPSAFE
422 */
423static int
424oshmctl(td, uap)
425 struct thread *td;
426 struct oshmctl_args *uap;
427{
428#ifdef COMPAT_43
429 int error = 0;
430 struct shmid_ds *shmseg;
431 struct oshmid_ds outbuf;
432
433 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
434 return (ENOSYS);
435 mtx_lock(&Giant);
436 shmseg = shm_find_segment_by_shmid(uap->shmid, 0);
437 if (shmseg == NULL) {
438 error = EINVAL;
439 goto done2;
440 }
441 switch (uap->cmd) {
442 case IPC_STAT:
443 error = ipcperm(td, &shmseg->shm_perm, IPC_R);
444 if (error)
445 goto done2;
446 outbuf.shm_perm = shmseg->shm_perm;
447 outbuf.shm_segsz = shmseg->shm_segsz;
448 outbuf.shm_cpid = shmseg->shm_cpid;
449 outbuf.shm_lpid = shmseg->shm_lpid;
450 outbuf.shm_nattch = shmseg->shm_nattch;
451 outbuf.shm_atime = shmseg->shm_atime;
452 outbuf.shm_dtime = shmseg->shm_dtime;
453 outbuf.shm_ctime = shmseg->shm_ctime;
454 outbuf.shm_handle = shmseg->shm_internal;
455 error = copyout(&outbuf, uap->ubuf, sizeof(outbuf));
456 if (error)
457 goto done2;
458 break;
459 default:
460 /* XXX casting to (sy_call_t *) is bogus, as usual. */
461 error = ((sy_call_t *)shmctl)(td, uap);
462 break;
463 }
464done2:
465 mtx_unlock(&Giant);
466 return (error);
467#else
468 return (EINVAL);
469#endif
470}
471
472#ifndef _SYS_SYSPROTO_H_
473struct shmctl_args {
474 int shmid;
475 int cmd;
476 struct shmid_ds *buf;
477};
478#endif
479
480/*
481 * MPSAFE
482 */
483int
484kern_shmctl(td, shmid, cmd, buf, bufsz, wantrem)
485 struct thread *td;
486 int shmid;
487 int cmd;
488 void *buf;
489 size_t *bufsz;
490 int wantrem;
491{
492 int error = 0;
493 struct shmid_ds *shmseg;
494
495 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
496 return (ENOSYS);
497
498 mtx_lock(&Giant);
499 switch (cmd) {
500 case IPC_INFO:
501 memcpy(buf, &shminfo, sizeof(shminfo));
502 if (bufsz)
503 *bufsz = sizeof(shminfo);
504 td->td_retval[0] = shmalloced;
505 goto done2;
506 case SHM_INFO: {
507 struct shm_info shm_info;
508 shm_info.used_ids = shm_nused;
509 shm_info.shm_rss = 0; /*XXX where to get from ? */
510 shm_info.shm_tot = 0; /*XXX where to get from ? */
511 shm_info.shm_swp = 0; /*XXX where to get from ? */
512 shm_info.swap_attempts = 0; /*XXX where to get from ? */
513 shm_info.swap_successes = 0; /*XXX where to get from ? */
514 memcpy(buf, &shm_info, sizeof(shm_info));
515 if (bufsz)
516 *bufsz = sizeof(shm_info);
517 td->td_retval[0] = shmalloced;
518 goto done2;
519 }
520 }
521 if (cmd == SHM_STAT)
522 shmseg = shm_find_segment_by_shmidx(shmid, wantrem);
523 else
524 shmseg = shm_find_segment_by_shmid(shmid, wantrem);
525 if (shmseg == NULL) {
526 error = EINVAL;
527 goto done2;
528 }
529 switch (cmd) {
530 case SHM_STAT:
531 case IPC_STAT:
532 error = ipcperm(td, &shmseg->shm_perm, IPC_R);
533 if (error)
534 goto done2;
535 memcpy(buf, shmseg, sizeof(struct shmid_ds));
536 if (bufsz)
537 *bufsz = sizeof(struct shmid_ds);
538 if (cmd == SHM_STAT)
539 td->td_retval[0] = IXSEQ_TO_IPCID(shmid, shmseg->shm_perm);
540 break;
541 case IPC_SET: {
542 struct shmid_ds *shmid;
543
544 shmid = (struct shmid_ds *)buf;
545 error = ipcperm(td, &shmseg->shm_perm, IPC_M);
546 if (error)
547 goto done2;
548 shmseg->shm_perm.uid = shmid->shm_perm.uid;
549 shmseg->shm_perm.gid = shmid->shm_perm.gid;
550 shmseg->shm_perm.mode =
551 (shmseg->shm_perm.mode & ~ACCESSPERMS) |
552 (shmid->shm_perm.mode & ACCESSPERMS);
553 shmseg->shm_ctime = time_second;
554 break;
555 }
556 case IPC_RMID:
557 error = ipcperm(td, &shmseg->shm_perm, IPC_M);
558 if (error)
559 goto done2;
560 shmseg->shm_perm.key = IPC_PRIVATE;
561 shmseg->shm_perm.mode |= SHMSEG_REMOVED;
562 if (shmseg->shm_nattch <= 0) {
563 shm_deallocate_segment(shmseg);
564 shm_last_free = IPCID_TO_IX(shmid);
565 }
566 break;
567#if 0
568 case SHM_LOCK:
569 case SHM_UNLOCK:
570#endif
571 default:
572 error = EINVAL;
573 break;
574 }
575done2:
576 mtx_unlock(&Giant);
577 return (error);
578}
579
580int
581shmctl(td, uap)
582 struct thread *td;
583 struct shmctl_args *uap;
584{
585 int error = 0;
586 struct shmid_ds buf;
587 size_t bufsz;
588
589 /* IPC_SET needs to copyin the buffer before calling kern_shmctl */
590 if (uap->cmd == IPC_SET) {
591 if ((error = copyin(uap->buf, &buf, sizeof(struct shmid_ds))))
592 goto done;
593 }
594
595 error = kern_shmctl(td, uap->shmid, uap->cmd, (void *)&buf, &bufsz, 0);
596 if (error)
597 goto done;
598
599 /* Cases in which we need to copyout */
600 switch (uap->cmd) {
601 case IPC_INFO:
602 case SHM_INFO:
603 case SHM_STAT:
604 case IPC_STAT:
605 error = copyout(&buf, uap->buf, bufsz);
606 break;
607 }
608
609done:
610 if (error) {
611 /* Invalidate the return value */
612 td->td_retval[0] = -1;
613 }
614 return (error);
615}
616
617
618#ifndef _SYS_SYSPROTO_H_
619struct shmget_args {
620 key_t key;
621 size_t size;
622 int shmflg;
623};
624#endif
625
626static int
627shmget_existing(td, uap, mode, segnum)
628 struct thread *td;
629 struct shmget_args *uap;
630 int mode;
631 int segnum;
632{
633 struct shmid_ds *shmseg;
634 int error;
635
636 shmseg = &shmsegs[segnum];
637 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) {
638 /*
639 * This segment is in the process of being allocated. Wait
640 * until it's done, and look the key up again (in case the
641 * allocation failed or it was freed).
642 */
643 shmseg->shm_perm.mode |= SHMSEG_WANTED;
644 error = tsleep(shmseg, PLOCK | PCATCH, "shmget", 0);
645 if (error)
646 return (error);
647 return (EAGAIN);
648 }
649 if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
650 return (EEXIST);
651 error = ipcperm(td, &shmseg->shm_perm, mode);
652 if (error)
653 return (error);
654 if (uap->size && uap->size > shmseg->shm_segsz)
655 return (EINVAL);
656 td->td_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
657 return (0);
658}
659
660static int
661shmget_allocate_segment(td, uap, mode)
662 struct thread *td;
663 struct shmget_args *uap;
664 int mode;
665{
666 int i, segnum, shmid, size;
667 struct ucred *cred = td->td_ucred;
668 struct shmid_ds *shmseg;
669 struct shm_handle *shm_handle;
670
671 GIANT_REQUIRED;
672
673 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
674 return (EINVAL);
675 if (shm_nused >= shminfo.shmmni) /* Any shmids left? */
676 return (ENOSPC);
677 size = round_page(uap->size);
678 if (shm_committed + btoc(size) > shminfo.shmall)
679 return (ENOMEM);
680 if (shm_last_free < 0) {
681 shmrealloc(); /* Maybe expand the shmsegs[] array. */
682 for (i = 0; i < shmalloced; i++)
683 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
684 break;
685 if (i == shmalloced)
686 return (ENOSPC);
687 segnum = i;
688 } else {
689 segnum = shm_last_free;
690 shm_last_free = -1;
691 }
692 shmseg = &shmsegs[segnum];
693 /*
694 * In case we sleep in malloc(), mark the segment present but deleted
695 * so that noone else tries to create the same key.
696 */
697 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
698 shmseg->shm_perm.key = uap->key;
699 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff;
700 shm_handle = (struct shm_handle *)
701 malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK);
702 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
703
704 /*
705 * We make sure that we have allocated a pager before we need
706 * to.
707 */
708 if (shm_use_phys) {
709 shm_handle->shm_object =
710 vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0);
711 } else {
712 shm_handle->shm_object =
713 vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0);
714 }
715 VM_OBJECT_LOCK(shm_handle->shm_object);
716 vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING);
717 vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT);
718 VM_OBJECT_UNLOCK(shm_handle->shm_object);
719
720 shmseg->shm_internal = shm_handle;
721 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid;
722 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid;
723 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
724 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
725 shmseg->shm_segsz = uap->size;
726 shmseg->shm_cpid = td->td_proc->p_pid;
727 shmseg->shm_lpid = shmseg->shm_nattch = 0;
728 shmseg->shm_atime = shmseg->shm_dtime = 0;
729 shmseg->shm_ctime = time_second;
730 shm_committed += btoc(size);
731 shm_nused++;
732 if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
733 /*
734 * Somebody else wanted this key while we were asleep. Wake
735 * them up now.
736 */
737 shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
738 wakeup(shmseg);
739 }
740 td->td_retval[0] = shmid;
741 return (0);
742}
743
744/*
745 * MPSAFE
746 */
747int
748shmget(td, uap)
749 struct thread *td;
750 struct shmget_args *uap;
751{
752 int segnum, mode;
753 int error;
754
755 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
756 return (ENOSYS);
757 mtx_lock(&Giant);
758 mode = uap->shmflg & ACCESSPERMS;
759 if (uap->key != IPC_PRIVATE) {
760 again:
761 segnum = shm_find_segment_by_key(uap->key);
762 if (segnum >= 0) {
763 error = shmget_existing(td, uap, mode, segnum);
764 if (error == EAGAIN)
765 goto again;
766 goto done2;
767 }
768 if ((uap->shmflg & IPC_CREAT) == 0) {
769 error = ENOENT;
770 goto done2;
771 }
772 }
773 error = shmget_allocate_segment(td, uap, mode);
774done2:
775 mtx_unlock(&Giant);
776 return (error);
777}
778
779/*
780 * MPSAFE
781 */
782int
783shmsys(td, uap)
784 struct thread *td;
785 /* XXX actually varargs. */
786 struct shmsys_args /* {
787 u_int which;
788 int a2;
789 int a3;
790 int a4;
791 } */ *uap;
792{
793 int error;
794
795 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
796 return (ENOSYS);
797 if (uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
798 return (EINVAL);
799 mtx_lock(&Giant);
800 error = (*shmcalls[uap->which])(td, &uap->a2);
801 mtx_unlock(&Giant);
802 return (error);
803}
804
805static void
806shmfork_myhook(p1, p2)
807 struct proc *p1, *p2;
808{
809 struct shmmap_state *shmmap_s;
810 size_t size;
811 int i;
812
813 size = shminfo.shmseg * sizeof(struct shmmap_state);
814 shmmap_s = malloc(size, M_SHM, M_WAITOK);
815 bcopy(p1->p_vmspace->vm_shm, shmmap_s, size);
816 p2->p_vmspace->vm_shm = shmmap_s;
817 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
818 if (shmmap_s->shmid != -1)
819 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++;
820}
821
822static void
823shmexit_myhook(struct vmspace *vm)
824{
825 struct shmmap_state *base, *shm;
826 int i;
827
828 GIANT_REQUIRED;
829
830 if ((base = vm->vm_shm) != NULL) {
831 vm->vm_shm = NULL;
832 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) {
833 if (shm->shmid != -1)
834 shm_delete_mapping(vm, shm);
835 }
836 free(base, M_SHM);
837 }
838}
839
840static void
841shmrealloc(void)
842{
843 int i;
844 struct shmid_ds *newsegs;
845
846 if (shmalloced >= shminfo.shmmni)
847 return;
848
849 newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
850 if (newsegs == NULL)
851 return;
852 for (i = 0; i < shmalloced; i++)
853 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
854 for (; i < shminfo.shmmni; i++) {
855 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
856 shmsegs[i].shm_perm.seq = 0;
857 }
858 free(shmsegs, M_SHM);
859 shmsegs = newsegs;
860 shmalloced = shminfo.shmmni;
861}
862
863static void
864shminit()
865{
866 int i;
867
868 TUNABLE_INT_FETCH("kern.ipc.shmmaxpgs", &shminfo.shmall);
869 for (i = PAGE_SIZE; i > 0; i--) {
870 shminfo.shmmax = shminfo.shmall * PAGE_SIZE;
871 if (shminfo.shmmax >= shminfo.shmall)
872 break;
873 }
874 TUNABLE_INT_FETCH("kern.ipc.shmmin", &shminfo.shmmin);
875 TUNABLE_INT_FETCH("kern.ipc.shmmni", &shminfo.shmmni);
876 TUNABLE_INT_FETCH("kern.ipc.shmseg", &shminfo.shmseg);
877 TUNABLE_INT_FETCH("kern.ipc.shm_use_phys", &shm_use_phys);
878
879 shmalloced = shminfo.shmmni;
880 shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
881 if (shmsegs == NULL)
882 panic("cannot allocate initial memory for sysvshm");
883 for (i = 0; i < shmalloced; i++) {
884 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
885 shmsegs[i].shm_perm.seq = 0;
886 }
887 shm_last_free = 0;
888 shm_nused = 0;
889 shm_committed = 0;
890 shmexit_hook = &shmexit_myhook;
891 shmfork_hook = &shmfork_myhook;
892}
893
894static int
895shmunload()
896{
897
898 if (shm_nused > 0)
899 return (EBUSY);
900
901 free(shmsegs, M_SHM);
902 shmexit_hook = NULL;
903 shmfork_hook = NULL;
904 return (0);
905}
906
907static int
908sysctl_shmsegs(SYSCTL_HANDLER_ARGS)
909{
910
911 return (SYSCTL_OUT(req, shmsegs, shmalloced * sizeof(shmsegs[0])));
912}
913
914static int
915sysvshm_modload(struct module *module, int cmd, void *arg)
916{
917 int error = 0;
918
919 switch (cmd) {
920 case MOD_LOAD:
921 shminit();
922 break;
923 case MOD_UNLOAD:
924 error = shmunload();
925 break;
926 case MOD_SHUTDOWN:
927 break;
928 default:
929 error = EINVAL;
930 break;
931 }
932 return (error);
933}
934
935static moduledata_t sysvshm_mod = {
936 "sysvshm",
937 &sysvshm_modload,
938 NULL
939};
940
941SYSCALL_MODULE_HELPER(shmsys);
942SYSCALL_MODULE_HELPER(shmat);
943SYSCALL_MODULE_HELPER(shmctl);
944SYSCALL_MODULE_HELPER(shmdt);
945SYSCALL_MODULE_HELPER(shmget);
946
947DECLARE_MODULE(sysvshm, sysvshm_mod,
948 SI_SUB_SYSV_SHM, SI_ORDER_FIRST);
949MODULE_VERSION(sysvshm, 1);
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#include <sys/cdefs.h>
33__FBSDID("$FreeBSD: head/sys/kern/sysv_shm.c 116182 2003-06-11 00:56:59Z obrien $");
34
35#include "opt_compat.h"
36#include "opt_sysvipc.h"
37
38#include <sys/param.h>
39#include <sys/systm.h>
40#include <sys/kernel.h>
41#include <sys/lock.h>
42#include <sys/sysctl.h>
43#include <sys/shm.h>
44#include <sys/proc.h>
45#include <sys/malloc.h>
46#include <sys/mman.h>
47#include <sys/mutex.h>
48#include <sys/stat.h>
49#include <sys/syscall.h>
50#include <sys/syscallsubr.h>
51#include <sys/sysent.h>
52#include <sys/sysproto.h>
53#include <sys/jail.h>
54
55#include <vm/vm.h>
56#include <vm/vm_param.h>
57#include <vm/pmap.h>
58#include <vm/vm_object.h>
59#include <vm/vm_map.h>
60#include <vm/vm_page.h>
61#include <vm/vm_pager.h>
62
63static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments");
64
65struct oshmctl_args;
66static int oshmctl(struct thread *td, struct oshmctl_args *uap);
67
68static int shmget_allocate_segment(struct thread *td,
69 struct shmget_args *uap, int mode);
70static int shmget_existing(struct thread *td, struct shmget_args *uap,
71 int mode, int segnum);
72
73/* XXX casting to (sy_call_t *) is bogus, as usual. */
74static sy_call_t *shmcalls[] = {
75 (sy_call_t *)shmat, (sy_call_t *)oshmctl,
76 (sy_call_t *)shmdt, (sy_call_t *)shmget,
77 (sy_call_t *)shmctl
78};
79
80#define SHMSEG_FREE 0x0200
81#define SHMSEG_REMOVED 0x0400
82#define SHMSEG_ALLOCATED 0x0800
83#define SHMSEG_WANTED 0x1000
84
85static int shm_last_free, shm_nused, shm_committed, shmalloced;
86static struct shmid_ds *shmsegs;
87
88struct shm_handle {
89 /* vm_offset_t kva; */
90 vm_object_t shm_object;
91};
92
93struct shmmap_state {
94 vm_offset_t va;
95 int shmid;
96};
97
98static void shm_deallocate_segment(struct shmid_ds *);
99static int shm_find_segment_by_key(key_t);
100static struct shmid_ds *shm_find_segment_by_shmid(int, int);
101static struct shmid_ds *shm_find_segment_by_shmidx(int, int);
102static int shm_delete_mapping(struct vmspace *vm, struct shmmap_state *);
103static void shmrealloc(void);
104static void shminit(void);
105static int sysvshm_modload(struct module *, int, void *);
106static int shmunload(void);
107static void shmexit_myhook(struct vmspace *vm);
108static void shmfork_myhook(struct proc *p1, struct proc *p2);
109static int sysctl_shmsegs(SYSCTL_HANDLER_ARGS);
110
111/*
112 * Tuneable values.
113 */
114#ifndef SHMMAXPGS
115#define SHMMAXPGS 8192 /* Note: sysv shared memory is swap backed. */
116#endif
117#ifndef SHMMAX
118#define SHMMAX (SHMMAXPGS*PAGE_SIZE)
119#endif
120#ifndef SHMMIN
121#define SHMMIN 1
122#endif
123#ifndef SHMMNI
124#define SHMMNI 192
125#endif
126#ifndef SHMSEG
127#define SHMSEG 128
128#endif
129#ifndef SHMALL
130#define SHMALL (SHMMAXPGS)
131#endif
132
133struct shminfo shminfo = {
134 SHMMAX,
135 SHMMIN,
136 SHMMNI,
137 SHMSEG,
138 SHMALL
139};
140
141static int shm_use_phys;
142
143SYSCTL_DECL(_kern_ipc);
144SYSCTL_INT(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, "");
145SYSCTL_INT(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, "");
146SYSCTL_INT(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0, "");
147SYSCTL_INT(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RD, &shminfo.shmseg, 0, "");
148SYSCTL_INT(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, "");
149SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW,
150 &shm_use_phys, 0, "");
151SYSCTL_PROC(_kern_ipc, OID_AUTO, shmsegs, CTLFLAG_RD,
152 NULL, 0, sysctl_shmsegs, "", "");
153
154static int
155shm_find_segment_by_key(key)
156 key_t key;
157{
158 int i;
159
160 for (i = 0; i < shmalloced; i++)
161 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) &&
162 shmsegs[i].shm_perm.key == key)
163 return (i);
164 return (-1);
165}
166
167static struct shmid_ds *
168shm_find_segment_by_shmid(int shmid, int wantrem)
169{
170 int segnum;
171 struct shmid_ds *shmseg;
172
173 segnum = IPCID_TO_IX(shmid);
174 if (segnum < 0 || segnum >= shmalloced)
175 return (NULL);
176 shmseg = &shmsegs[segnum];
177 if (!((shmseg->shm_perm.mode & SHMSEG_ALLOCATED) ||
178 (wantrem && !(shmseg->shm_perm.mode & SHMSEG_REMOVED))) ||
179 shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid))
180 return (NULL);
181 return (shmseg);
182}
183
184static struct shmid_ds *
185shm_find_segment_by_shmidx(int segnum, int wantrem)
186{
187 struct shmid_ds *shmseg;
188
189 if (segnum < 0 || segnum >= shmalloced)
190 return (NULL);
191 shmseg = &shmsegs[segnum];
192 if (!((shmseg->shm_perm.mode & SHMSEG_ALLOCATED) ||
193 (wantrem && !(shmseg->shm_perm.mode & SHMSEG_REMOVED))))
194 return (NULL);
195 return (shmseg);
196}
197
198static void
199shm_deallocate_segment(shmseg)
200 struct shmid_ds *shmseg;
201{
202 struct shm_handle *shm_handle;
203 size_t size;
204
205 GIANT_REQUIRED;
206
207 shm_handle = shmseg->shm_internal;
208 vm_object_deallocate(shm_handle->shm_object);
209 free(shm_handle, M_SHM);
210 shmseg->shm_internal = NULL;
211 size = round_page(shmseg->shm_segsz);
212 shm_committed -= btoc(size);
213 shm_nused--;
214 shmseg->shm_perm.mode = SHMSEG_FREE;
215}
216
217static int
218shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s)
219{
220 struct shmid_ds *shmseg;
221 int segnum, result;
222 size_t size;
223
224 GIANT_REQUIRED;
225
226 segnum = IPCID_TO_IX(shmmap_s->shmid);
227 shmseg = &shmsegs[segnum];
228 size = round_page(shmseg->shm_segsz);
229 result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size);
230 if (result != KERN_SUCCESS)
231 return (EINVAL);
232 shmmap_s->shmid = -1;
233 shmseg->shm_dtime = time_second;
234 if ((--shmseg->shm_nattch <= 0) &&
235 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) {
236 shm_deallocate_segment(shmseg);
237 shm_last_free = segnum;
238 }
239 return (0);
240}
241
242#ifndef _SYS_SYSPROTO_H_
243struct shmdt_args {
244 const void *shmaddr;
245};
246#endif
247
248/*
249 * MPSAFE
250 */
251int
252shmdt(td, uap)
253 struct thread *td;
254 struct shmdt_args *uap;
255{
256 struct proc *p = td->td_proc;
257 struct shmmap_state *shmmap_s;
258 int i;
259 int error = 0;
260
261 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
262 return (ENOSYS);
263 mtx_lock(&Giant);
264 shmmap_s = p->p_vmspace->vm_shm;
265 if (shmmap_s == NULL) {
266 error = EINVAL;
267 goto done2;
268 }
269 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) {
270 if (shmmap_s->shmid != -1 &&
271 shmmap_s->va == (vm_offset_t)uap->shmaddr) {
272 break;
273 }
274 }
275 if (i == shminfo.shmseg) {
276 error = EINVAL;
277 goto done2;
278 }
279 error = shm_delete_mapping(p->p_vmspace, shmmap_s);
280done2:
281 mtx_unlock(&Giant);
282 return (error);
283}
284
285#ifndef _SYS_SYSPROTO_H_
286struct shmat_args {
287 int shmid;
288 const void *shmaddr;
289 int shmflg;
290};
291#endif
292
293/*
294 * MPSAFE
295 */
296int
297kern_shmat(td, shmid, shmaddr, shmflg, wantrem)
298 struct thread *td;
299 int shmid;
300 const void *shmaddr;
301 int shmflg;
302 int wantrem;
303{
304 struct proc *p = td->td_proc;
305 int i, flags;
306 struct shmid_ds *shmseg;
307 struct shmmap_state *shmmap_s = NULL;
308 struct shm_handle *shm_handle;
309 vm_offset_t attach_va;
310 vm_prot_t prot;
311 vm_size_t size;
312 int rv;
313 int error = 0;
314
315 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
316 return (ENOSYS);
317 mtx_lock(&Giant);
318 shmmap_s = p->p_vmspace->vm_shm;
319 if (shmmap_s == NULL) {
320 size = shminfo.shmseg * sizeof(struct shmmap_state);
321 shmmap_s = malloc(size, M_SHM, M_WAITOK);
322 for (i = 0; i < shminfo.shmseg; i++)
323 shmmap_s[i].shmid = -1;
324 p->p_vmspace->vm_shm = shmmap_s;
325 }
326 shmseg = shm_find_segment_by_shmid(shmid, wantrem);
327 if (shmseg == NULL) {
328 error = EINVAL;
329 goto done2;
330 }
331 error = ipcperm(td, &shmseg->shm_perm,
332 (shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
333 if (error)
334 goto done2;
335 for (i = 0; i < shminfo.shmseg; i++) {
336 if (shmmap_s->shmid == -1)
337 break;
338 shmmap_s++;
339 }
340 if (i >= shminfo.shmseg) {
341 error = EMFILE;
342 goto done2;
343 }
344 size = round_page(shmseg->shm_segsz);
345#ifdef VM_PROT_READ_IS_EXEC
346 prot = VM_PROT_READ | VM_PROT_EXECUTE;
347#else
348 prot = VM_PROT_READ;
349#endif
350 if ((shmflg & SHM_RDONLY) == 0)
351 prot |= VM_PROT_WRITE;
352 flags = MAP_ANON | MAP_SHARED;
353 if (shmaddr) {
354 flags |= MAP_FIXED;
355 if (shmflg & SHM_RND) {
356 attach_va = (vm_offset_t)shmaddr & ~(SHMLBA-1);
357 } else if (((vm_offset_t)shmaddr & (SHMLBA-1)) == 0) {
358 attach_va = (vm_offset_t)shmaddr;
359 } else {
360 error = EINVAL;
361 goto done2;
362 }
363 } else {
364 /*
365 * This is just a hint to vm_map_find() about where to
366 * put it.
367 */
368 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr
369 + maxtsiz + maxdsiz);
370 }
371
372 shm_handle = shmseg->shm_internal;
373 vm_object_reference(shm_handle->shm_object);
374 rv = vm_map_find(&p->p_vmspace->vm_map, shm_handle->shm_object,
375 0, &attach_va, size, (flags & MAP_FIXED)?0:1, prot, prot, 0);
376 if (rv != KERN_SUCCESS) {
377 error = ENOMEM;
378 goto done2;
379 }
380 vm_map_inherit(&p->p_vmspace->vm_map,
381 attach_va, attach_va + size, VM_INHERIT_SHARE);
382
383 shmmap_s->va = attach_va;
384 shmmap_s->shmid = shmid;
385 shmseg->shm_lpid = p->p_pid;
386 shmseg->shm_atime = time_second;
387 shmseg->shm_nattch++;
388 td->td_retval[0] = attach_va;
389done2:
390 mtx_unlock(&Giant);
391 return (error);
392}
393
394int
395shmat(td, uap)
396 struct thread *td;
397 struct shmat_args *uap;
398{
399 return kern_shmat(td, uap->shmid, uap->shmaddr, uap->shmflg, 0);
400}
401
402struct oshmid_ds {
403 struct ipc_perm shm_perm; /* operation perms */
404 int shm_segsz; /* size of segment (bytes) */
405 ushort shm_cpid; /* pid, creator */
406 ushort shm_lpid; /* pid, last operation */
407 short shm_nattch; /* no. of current attaches */
408 time_t shm_atime; /* last attach time */
409 time_t shm_dtime; /* last detach time */
410 time_t shm_ctime; /* last change time */
411 void *shm_handle; /* internal handle for shm segment */
412};
413
414struct oshmctl_args {
415 int shmid;
416 int cmd;
417 struct oshmid_ds *ubuf;
418};
419
420/*
421 * MPSAFE
422 */
423static int
424oshmctl(td, uap)
425 struct thread *td;
426 struct oshmctl_args *uap;
427{
428#ifdef COMPAT_43
429 int error = 0;
430 struct shmid_ds *shmseg;
431 struct oshmid_ds outbuf;
432
433 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
434 return (ENOSYS);
435 mtx_lock(&Giant);
436 shmseg = shm_find_segment_by_shmid(uap->shmid, 0);
437 if (shmseg == NULL) {
438 error = EINVAL;
439 goto done2;
440 }
441 switch (uap->cmd) {
442 case IPC_STAT:
443 error = ipcperm(td, &shmseg->shm_perm, IPC_R);
444 if (error)
445 goto done2;
446 outbuf.shm_perm = shmseg->shm_perm;
447 outbuf.shm_segsz = shmseg->shm_segsz;
448 outbuf.shm_cpid = shmseg->shm_cpid;
449 outbuf.shm_lpid = shmseg->shm_lpid;
450 outbuf.shm_nattch = shmseg->shm_nattch;
451 outbuf.shm_atime = shmseg->shm_atime;
452 outbuf.shm_dtime = shmseg->shm_dtime;
453 outbuf.shm_ctime = shmseg->shm_ctime;
454 outbuf.shm_handle = shmseg->shm_internal;
455 error = copyout(&outbuf, uap->ubuf, sizeof(outbuf));
456 if (error)
457 goto done2;
458 break;
459 default:
460 /* XXX casting to (sy_call_t *) is bogus, as usual. */
461 error = ((sy_call_t *)shmctl)(td, uap);
462 break;
463 }
464done2:
465 mtx_unlock(&Giant);
466 return (error);
467#else
468 return (EINVAL);
469#endif
470}
471
472#ifndef _SYS_SYSPROTO_H_
473struct shmctl_args {
474 int shmid;
475 int cmd;
476 struct shmid_ds *buf;
477};
478#endif
479
480/*
481 * MPSAFE
482 */
483int
484kern_shmctl(td, shmid, cmd, buf, bufsz, wantrem)
485 struct thread *td;
486 int shmid;
487 int cmd;
488 void *buf;
489 size_t *bufsz;
490 int wantrem;
491{
492 int error = 0;
493 struct shmid_ds *shmseg;
494
495 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
496 return (ENOSYS);
497
498 mtx_lock(&Giant);
499 switch (cmd) {
500 case IPC_INFO:
501 memcpy(buf, &shminfo, sizeof(shminfo));
502 if (bufsz)
503 *bufsz = sizeof(shminfo);
504 td->td_retval[0] = shmalloced;
505 goto done2;
506 case SHM_INFO: {
507 struct shm_info shm_info;
508 shm_info.used_ids = shm_nused;
509 shm_info.shm_rss = 0; /*XXX where to get from ? */
510 shm_info.shm_tot = 0; /*XXX where to get from ? */
511 shm_info.shm_swp = 0; /*XXX where to get from ? */
512 shm_info.swap_attempts = 0; /*XXX where to get from ? */
513 shm_info.swap_successes = 0; /*XXX where to get from ? */
514 memcpy(buf, &shm_info, sizeof(shm_info));
515 if (bufsz)
516 *bufsz = sizeof(shm_info);
517 td->td_retval[0] = shmalloced;
518 goto done2;
519 }
520 }
521 if (cmd == SHM_STAT)
522 shmseg = shm_find_segment_by_shmidx(shmid, wantrem);
523 else
524 shmseg = shm_find_segment_by_shmid(shmid, wantrem);
525 if (shmseg == NULL) {
526 error = EINVAL;
527 goto done2;
528 }
529 switch (cmd) {
530 case SHM_STAT:
531 case IPC_STAT:
532 error = ipcperm(td, &shmseg->shm_perm, IPC_R);
533 if (error)
534 goto done2;
535 memcpy(buf, shmseg, sizeof(struct shmid_ds));
536 if (bufsz)
537 *bufsz = sizeof(struct shmid_ds);
538 if (cmd == SHM_STAT)
539 td->td_retval[0] = IXSEQ_TO_IPCID(shmid, shmseg->shm_perm);
540 break;
541 case IPC_SET: {
542 struct shmid_ds *shmid;
543
544 shmid = (struct shmid_ds *)buf;
545 error = ipcperm(td, &shmseg->shm_perm, IPC_M);
546 if (error)
547 goto done2;
548 shmseg->shm_perm.uid = shmid->shm_perm.uid;
549 shmseg->shm_perm.gid = shmid->shm_perm.gid;
550 shmseg->shm_perm.mode =
551 (shmseg->shm_perm.mode & ~ACCESSPERMS) |
552 (shmid->shm_perm.mode & ACCESSPERMS);
553 shmseg->shm_ctime = time_second;
554 break;
555 }
556 case IPC_RMID:
557 error = ipcperm(td, &shmseg->shm_perm, IPC_M);
558 if (error)
559 goto done2;
560 shmseg->shm_perm.key = IPC_PRIVATE;
561 shmseg->shm_perm.mode |= SHMSEG_REMOVED;
562 if (shmseg->shm_nattch <= 0) {
563 shm_deallocate_segment(shmseg);
564 shm_last_free = IPCID_TO_IX(shmid);
565 }
566 break;
567#if 0
568 case SHM_LOCK:
569 case SHM_UNLOCK:
570#endif
571 default:
572 error = EINVAL;
573 break;
574 }
575done2:
576 mtx_unlock(&Giant);
577 return (error);
578}
579
580int
581shmctl(td, uap)
582 struct thread *td;
583 struct shmctl_args *uap;
584{
585 int error = 0;
586 struct shmid_ds buf;
587 size_t bufsz;
588
589 /* IPC_SET needs to copyin the buffer before calling kern_shmctl */
590 if (uap->cmd == IPC_SET) {
591 if ((error = copyin(uap->buf, &buf, sizeof(struct shmid_ds))))
592 goto done;
593 }
594
595 error = kern_shmctl(td, uap->shmid, uap->cmd, (void *)&buf, &bufsz, 0);
596 if (error)
597 goto done;
598
599 /* Cases in which we need to copyout */
600 switch (uap->cmd) {
601 case IPC_INFO:
602 case SHM_INFO:
603 case SHM_STAT:
604 case IPC_STAT:
605 error = copyout(&buf, uap->buf, bufsz);
606 break;
607 }
608
609done:
610 if (error) {
611 /* Invalidate the return value */
612 td->td_retval[0] = -1;
613 }
614 return (error);
615}
616
617
618#ifndef _SYS_SYSPROTO_H_
619struct shmget_args {
620 key_t key;
621 size_t size;
622 int shmflg;
623};
624#endif
625
626static int
627shmget_existing(td, uap, mode, segnum)
628 struct thread *td;
629 struct shmget_args *uap;
630 int mode;
631 int segnum;
632{
633 struct shmid_ds *shmseg;
634 int error;
635
636 shmseg = &shmsegs[segnum];
637 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) {
638 /*
639 * This segment is in the process of being allocated. Wait
640 * until it's done, and look the key up again (in case the
641 * allocation failed or it was freed).
642 */
643 shmseg->shm_perm.mode |= SHMSEG_WANTED;
644 error = tsleep(shmseg, PLOCK | PCATCH, "shmget", 0);
645 if (error)
646 return (error);
647 return (EAGAIN);
648 }
649 if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
650 return (EEXIST);
651 error = ipcperm(td, &shmseg->shm_perm, mode);
652 if (error)
653 return (error);
654 if (uap->size && uap->size > shmseg->shm_segsz)
655 return (EINVAL);
656 td->td_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
657 return (0);
658}
659
660static int
661shmget_allocate_segment(td, uap, mode)
662 struct thread *td;
663 struct shmget_args *uap;
664 int mode;
665{
666 int i, segnum, shmid, size;
667 struct ucred *cred = td->td_ucred;
668 struct shmid_ds *shmseg;
669 struct shm_handle *shm_handle;
670
671 GIANT_REQUIRED;
672
673 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
674 return (EINVAL);
675 if (shm_nused >= shminfo.shmmni) /* Any shmids left? */
676 return (ENOSPC);
677 size = round_page(uap->size);
678 if (shm_committed + btoc(size) > shminfo.shmall)
679 return (ENOMEM);
680 if (shm_last_free < 0) {
681 shmrealloc(); /* Maybe expand the shmsegs[] array. */
682 for (i = 0; i < shmalloced; i++)
683 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
684 break;
685 if (i == shmalloced)
686 return (ENOSPC);
687 segnum = i;
688 } else {
689 segnum = shm_last_free;
690 shm_last_free = -1;
691 }
692 shmseg = &shmsegs[segnum];
693 /*
694 * In case we sleep in malloc(), mark the segment present but deleted
695 * so that noone else tries to create the same key.
696 */
697 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
698 shmseg->shm_perm.key = uap->key;
699 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff;
700 shm_handle = (struct shm_handle *)
701 malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK);
702 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
703
704 /*
705 * We make sure that we have allocated a pager before we need
706 * to.
707 */
708 if (shm_use_phys) {
709 shm_handle->shm_object =
710 vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0);
711 } else {
712 shm_handle->shm_object =
713 vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0);
714 }
715 VM_OBJECT_LOCK(shm_handle->shm_object);
716 vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING);
717 vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT);
718 VM_OBJECT_UNLOCK(shm_handle->shm_object);
719
720 shmseg->shm_internal = shm_handle;
721 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid;
722 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid;
723 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
724 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
725 shmseg->shm_segsz = uap->size;
726 shmseg->shm_cpid = td->td_proc->p_pid;
727 shmseg->shm_lpid = shmseg->shm_nattch = 0;
728 shmseg->shm_atime = shmseg->shm_dtime = 0;
729 shmseg->shm_ctime = time_second;
730 shm_committed += btoc(size);
731 shm_nused++;
732 if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
733 /*
734 * Somebody else wanted this key while we were asleep. Wake
735 * them up now.
736 */
737 shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
738 wakeup(shmseg);
739 }
740 td->td_retval[0] = shmid;
741 return (0);
742}
743
744/*
745 * MPSAFE
746 */
747int
748shmget(td, uap)
749 struct thread *td;
750 struct shmget_args *uap;
751{
752 int segnum, mode;
753 int error;
754
755 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
756 return (ENOSYS);
757 mtx_lock(&Giant);
758 mode = uap->shmflg & ACCESSPERMS;
759 if (uap->key != IPC_PRIVATE) {
760 again:
761 segnum = shm_find_segment_by_key(uap->key);
762 if (segnum >= 0) {
763 error = shmget_existing(td, uap, mode, segnum);
764 if (error == EAGAIN)
765 goto again;
766 goto done2;
767 }
768 if ((uap->shmflg & IPC_CREAT) == 0) {
769 error = ENOENT;
770 goto done2;
771 }
772 }
773 error = shmget_allocate_segment(td, uap, mode);
774done2:
775 mtx_unlock(&Giant);
776 return (error);
777}
778
779/*
780 * MPSAFE
781 */
782int
783shmsys(td, uap)
784 struct thread *td;
785 /* XXX actually varargs. */
786 struct shmsys_args /* {
787 u_int which;
788 int a2;
789 int a3;
790 int a4;
791 } */ *uap;
792{
793 int error;
794
795 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
796 return (ENOSYS);
797 if (uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
798 return (EINVAL);
799 mtx_lock(&Giant);
800 error = (*shmcalls[uap->which])(td, &uap->a2);
801 mtx_unlock(&Giant);
802 return (error);
803}
804
805static void
806shmfork_myhook(p1, p2)
807 struct proc *p1, *p2;
808{
809 struct shmmap_state *shmmap_s;
810 size_t size;
811 int i;
812
813 size = shminfo.shmseg * sizeof(struct shmmap_state);
814 shmmap_s = malloc(size, M_SHM, M_WAITOK);
815 bcopy(p1->p_vmspace->vm_shm, shmmap_s, size);
816 p2->p_vmspace->vm_shm = shmmap_s;
817 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
818 if (shmmap_s->shmid != -1)
819 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++;
820}
821
822static void
823shmexit_myhook(struct vmspace *vm)
824{
825 struct shmmap_state *base, *shm;
826 int i;
827
828 GIANT_REQUIRED;
829
830 if ((base = vm->vm_shm) != NULL) {
831 vm->vm_shm = NULL;
832 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) {
833 if (shm->shmid != -1)
834 shm_delete_mapping(vm, shm);
835 }
836 free(base, M_SHM);
837 }
838}
839
840static void
841shmrealloc(void)
842{
843 int i;
844 struct shmid_ds *newsegs;
845
846 if (shmalloced >= shminfo.shmmni)
847 return;
848
849 newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
850 if (newsegs == NULL)
851 return;
852 for (i = 0; i < shmalloced; i++)
853 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
854 for (; i < shminfo.shmmni; i++) {
855 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
856 shmsegs[i].shm_perm.seq = 0;
857 }
858 free(shmsegs, M_SHM);
859 shmsegs = newsegs;
860 shmalloced = shminfo.shmmni;
861}
862
863static void
864shminit()
865{
866 int i;
867
868 TUNABLE_INT_FETCH("kern.ipc.shmmaxpgs", &shminfo.shmall);
869 for (i = PAGE_SIZE; i > 0; i--) {
870 shminfo.shmmax = shminfo.shmall * PAGE_SIZE;
871 if (shminfo.shmmax >= shminfo.shmall)
872 break;
873 }
874 TUNABLE_INT_FETCH("kern.ipc.shmmin", &shminfo.shmmin);
875 TUNABLE_INT_FETCH("kern.ipc.shmmni", &shminfo.shmmni);
876 TUNABLE_INT_FETCH("kern.ipc.shmseg", &shminfo.shmseg);
877 TUNABLE_INT_FETCH("kern.ipc.shm_use_phys", &shm_use_phys);
878
879 shmalloced = shminfo.shmmni;
880 shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
881 if (shmsegs == NULL)
882 panic("cannot allocate initial memory for sysvshm");
883 for (i = 0; i < shmalloced; i++) {
884 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
885 shmsegs[i].shm_perm.seq = 0;
886 }
887 shm_last_free = 0;
888 shm_nused = 0;
889 shm_committed = 0;
890 shmexit_hook = &shmexit_myhook;
891 shmfork_hook = &shmfork_myhook;
892}
893
894static int
895shmunload()
896{
897
898 if (shm_nused > 0)
899 return (EBUSY);
900
901 free(shmsegs, M_SHM);
902 shmexit_hook = NULL;
903 shmfork_hook = NULL;
904 return (0);
905}
906
907static int
908sysctl_shmsegs(SYSCTL_HANDLER_ARGS)
909{
910
911 return (SYSCTL_OUT(req, shmsegs, shmalloced * sizeof(shmsegs[0])));
912}
913
914static int
915sysvshm_modload(struct module *module, int cmd, void *arg)
916{
917 int error = 0;
918
919 switch (cmd) {
920 case MOD_LOAD:
921 shminit();
922 break;
923 case MOD_UNLOAD:
924 error = shmunload();
925 break;
926 case MOD_SHUTDOWN:
927 break;
928 default:
929 error = EINVAL;
930 break;
931 }
932 return (error);
933}
934
935static moduledata_t sysvshm_mod = {
936 "sysvshm",
937 &sysvshm_modload,
938 NULL
939};
940
941SYSCALL_MODULE_HELPER(shmsys);
942SYSCALL_MODULE_HELPER(shmat);
943SYSCALL_MODULE_HELPER(shmctl);
944SYSCALL_MODULE_HELPER(shmdt);
945SYSCALL_MODULE_HELPER(shmget);
946
947DECLARE_MODULE(sysvshm, sysvshm_mod,
948 SI_SUB_SYSV_SHM, SI_ORDER_FIRST);
949MODULE_VERSION(sysvshm, 1);