1 /* $FreeBSD: src/sys/kern/sysv_shm.c,v 1.45.2.6 2002/10/22 20:45:03 fjoe Exp $ */
2 /* $DragonFly: src/sys/kern/sysv_shm.c,v 1.21 2008/01/06 16:55:51 swildner Exp $ */
3 /* $NetBSD: sysv_shm.c,v 1.23 1994/07/04 23:25:12 glass Exp $ */
6 * Copyright (c) 1994 Adam Glass and Charles Hannum. All rights reserved.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by Adam Glass and Charles
20 * 4. The names of the authors may not be used to endorse or promote products
21 * derived from this software without specific prior written permission.
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35 #include "opt_compat.h"
36 #include "opt_sysvipc.h"
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/sysproto.h>
41 #include <sys/kernel.h>
42 #include <sys/sysctl.h>
45 #include <sys/malloc.h>
48 #include <sys/sysent.h>
51 #include <sys/mplock2.h>
54 #include <vm/vm_param.h>
57 #include <vm/vm_object.h>
58 #include <vm/vm_map.h>
59 #include <vm/vm_page.h>
60 #include <vm/vm_pager.h>
62 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments");
65 static int sys_oshmctl (struct proc *p, struct oshmctl_args *uap);
67 static int shmget_allocate_segment (struct proc *p, struct shmget_args *uap, int mode);
68 static int shmget_existing (struct proc *p, struct shmget_args *uap, int mode, int segnum);
70 /* XXX casting to (sy_call_t *) is bogus, as usual. */
71 static sy_call_t *shmcalls[] = {
72 (sy_call_t *)sys_shmat, (sy_call_t *)sys_oshmctl,
73 (sy_call_t *)sys_shmdt, (sy_call_t *)sys_shmget,
74 (sy_call_t *)sys_shmctl
77 #define SHMSEG_FREE 0x0200
78 #define SHMSEG_REMOVED 0x0400
79 #define SHMSEG_ALLOCATED 0x0800
80 #define SHMSEG_WANTED 0x1000
82 static int shm_last_free, shm_nused, shm_committed, shmalloced;
83 static struct shmid_ds *shmsegs;
86 /* vm_offset_t kva; */
87 vm_object_t shm_object;
95 static void shm_deallocate_segment (struct shmid_ds *);
96 static int shm_find_segment_by_key (key_t);
97 static struct shmid_ds *shm_find_segment_by_shmid (int);
98 static int shm_delete_mapping (struct vmspace *vm, struct shmmap_state *);
99 static void shmrealloc (void);
100 static void shminit (void *);
106 #define SHMMAXPGS 8192 /* note: sysv shared memory is swap backed */
109 #define SHMMAX (SHMMAXPGS*PAGE_SIZE)
121 #define SHMALL (SHMMAXPGS)
124 struct shminfo shminfo = {
132 static int shm_use_phys;
134 TUNABLE_INT("kern.ipc.shmmin", &shminfo.shmmin);
135 TUNABLE_INT("kern.ipc.shmmni", &shminfo.shmmni);
136 TUNABLE_INT("kern.ipc.shmseg", &shminfo.shmseg);
137 TUNABLE_INT("kern.ipc.shmmaxpgs", &shminfo.shmall);
138 TUNABLE_INT("kern.ipc.shm_use_phys", &shm_use_phys);
140 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, "");
141 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, "");
142 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0, "");
143 SYSCTL_INT(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RW, &shminfo.shmseg, 0, "");
144 SYSCTL_INT(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, "");
145 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, &shm_use_phys, 0, "");
148 shm_find_segment_by_key(key_t key)
152 for (i = 0; i < shmalloced; i++)
153 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) &&
154 shmsegs[i].shm_perm.key == key)
159 static struct shmid_ds *
160 shm_find_segment_by_shmid(int shmid)
163 struct shmid_ds *shmseg;
165 segnum = IPCID_TO_IX(shmid);
166 if (segnum < 0 || segnum >= shmalloced)
168 shmseg = &shmsegs[segnum];
169 if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED))
170 != SHMSEG_ALLOCATED ||
171 shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid))
177 shm_deallocate_segment(struct shmid_ds *shmseg)
179 struct shm_handle *shm_handle;
182 shm_handle = shmseg->shm_internal;
183 vm_object_deallocate(shm_handle->shm_object);
184 kfree((caddr_t)shm_handle, M_SHM);
185 shmseg->shm_internal = NULL;
186 size = round_page(shmseg->shm_segsz);
187 shm_committed -= btoc(size);
189 shmseg->shm_perm.mode = SHMSEG_FREE;
193 shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s)
195 struct shmid_ds *shmseg;
199 segnum = IPCID_TO_IX(shmmap_s->shmid);
200 shmseg = &shmsegs[segnum];
201 size = round_page(shmseg->shm_segsz);
202 result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size);
203 if (result != KERN_SUCCESS)
205 shmmap_s->shmid = -1;
206 shmseg->shm_dtime = time_second;
207 if ((--shmseg->shm_nattch <= 0) &&
208 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) {
209 shm_deallocate_segment(shmseg);
210 shm_last_free = segnum;
219 sys_shmdt(struct shmdt_args *uap)
221 struct thread *td = curthread;
222 struct proc *p = td->td_proc;
223 struct shmmap_state *shmmap_s;
227 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
231 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
232 if (shmmap_s == NULL) {
236 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) {
237 if (shmmap_s->shmid != -1 &&
238 shmmap_s->va == (vm_offset_t)uap->shmaddr)
241 if (i == shminfo.shmseg)
244 error = shm_delete_mapping(p->p_vmspace, shmmap_s);
254 sys_shmat(struct shmat_args *uap)
256 struct thread *td = curthread;
257 struct proc *p = td->td_proc;
259 struct shmid_ds *shmseg;
260 struct shmmap_state *shmmap_s = NULL;
261 struct shm_handle *shm_handle;
262 vm_offset_t attach_va;
267 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
272 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
273 if (shmmap_s == NULL) {
274 size = shminfo.shmseg * sizeof(struct shmmap_state);
275 shmmap_s = kmalloc(size, M_SHM, M_WAITOK);
276 for (i = 0; i < shminfo.shmseg; i++)
277 shmmap_s[i].shmid = -1;
278 if (p->p_vmspace->vm_shm != NULL) {
279 kfree(shmmap_s, M_SHM);
282 p->p_vmspace->vm_shm = (caddr_t)shmmap_s;
284 shmseg = shm_find_segment_by_shmid(uap->shmid);
285 if (shmseg == NULL) {
289 error = ipcperm(p, &shmseg->shm_perm,
290 (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
293 for (i = 0; i < shminfo.shmseg; i++) {
294 if (shmmap_s->shmid == -1)
298 if (i >= shminfo.shmseg) {
302 size = round_page(shmseg->shm_segsz);
303 #ifdef VM_PROT_READ_IS_EXEC
304 prot = VM_PROT_READ | VM_PROT_EXECUTE;
308 if ((uap->shmflg & SHM_RDONLY) == 0)
309 prot |= VM_PROT_WRITE;
310 flags = MAP_ANON | MAP_SHARED;
313 if (uap->shmflg & SHM_RND) {
314 attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1);
315 } else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0) {
316 attach_va = (vm_offset_t)uap->shmaddr;
323 * This is just a hint to vm_map_find() about where to put it.
325 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr + maxtsiz + maxdsiz);
328 shm_handle = shmseg->shm_internal;
329 vm_object_reference(shm_handle->shm_object);
330 rv = vm_map_find(&p->p_vmspace->vm_map,
331 shm_handle->shm_object, 0,
333 ((flags & MAP_FIXED) ? 0 : 1),
337 if (rv != KERN_SUCCESS) {
338 vm_object_deallocate(shm_handle->shm_object);
342 vm_map_inherit(&p->p_vmspace->vm_map,
343 attach_va, attach_va + size, VM_INHERIT_SHARE);
345 KKASSERT(shmmap_s->shmid == -1);
346 shmmap_s->va = attach_va;
347 shmmap_s->shmid = uap->shmid;
348 shmseg->shm_lpid = p->p_pid;
349 shmseg->shm_atime = time_second;
350 shmseg->shm_nattch++;
351 uap->sysmsg_result = attach_va;
359 struct ipc_perm shm_perm; /* operation perms */
360 int shm_segsz; /* size of segment (bytes) */
361 ushort shm_cpid; /* pid, creator */
362 ushort shm_lpid; /* pid, last operation */
363 short shm_nattch; /* no. of current attaches */
364 time_t shm_atime; /* last attach time */
365 time_t shm_dtime; /* last detach time */
366 time_t shm_ctime; /* last change time */
367 void *shm_handle; /* internal handle for shm segment */
370 struct oshmctl_args {
371 struct sysmsg sysmsg;
374 struct oshmid_ds *ubuf;
381 sys_oshmctl(struct proc *p, struct oshmctl_args *uap)
384 struct thread *td = curthread;
385 struct shmid_ds *shmseg;
386 struct oshmid_ds outbuf;
389 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
393 shmseg = shm_find_segment_by_shmid(uap->shmid);
394 if (shmseg == NULL) {
401 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
404 outbuf.shm_perm = shmseg->shm_perm;
405 outbuf.shm_segsz = shmseg->shm_segsz;
406 outbuf.shm_cpid = shmseg->shm_cpid;
407 outbuf.shm_lpid = shmseg->shm_lpid;
408 outbuf.shm_nattch = shmseg->shm_nattch;
409 outbuf.shm_atime = shmseg->shm_atime;
410 outbuf.shm_dtime = shmseg->shm_dtime;
411 outbuf.shm_ctime = shmseg->shm_ctime;
412 outbuf.shm_handle = shmseg->shm_internal;
413 error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf));
416 /* XXX casting to (sy_call_t *) is bogus, as usual. */
417 error = sys_shmctl((struct shmctl_args *)uap);
431 sys_shmctl(struct shmctl_args *uap)
433 struct thread *td = curthread;
434 struct proc *p = td->td_proc;
436 struct shmid_ds inbuf;
437 struct shmid_ds *shmseg;
439 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
443 shmseg = shm_find_segment_by_shmid(uap->shmid);
444 if (shmseg == NULL) {
451 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
453 error = copyout(shmseg, uap->buf, sizeof(inbuf));
456 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
458 error = copyin(uap->buf, &inbuf, sizeof(inbuf));
460 shmseg->shm_perm.uid = inbuf.shm_perm.uid;
461 shmseg->shm_perm.gid = inbuf.shm_perm.gid;
462 shmseg->shm_perm.mode =
463 (shmseg->shm_perm.mode & ~ACCESSPERMS) |
464 (inbuf.shm_perm.mode & ACCESSPERMS);
465 shmseg->shm_ctime = time_second;
469 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
471 shmseg->shm_perm.key = IPC_PRIVATE;
472 shmseg->shm_perm.mode |= SHMSEG_REMOVED;
473 if (shmseg->shm_nattch <= 0) {
474 shm_deallocate_segment(shmseg);
475 shm_last_free = IPCID_TO_IX(uap->shmid);
493 shmget_existing(struct proc *p, struct shmget_args *uap, int mode, int segnum)
495 struct shmid_ds *shmseg;
498 shmseg = &shmsegs[segnum];
499 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) {
501 * This segment is in the process of being allocated. Wait
502 * until it's done, and look the key up again (in case the
503 * allocation failed or it was freed).
505 shmseg->shm_perm.mode |= SHMSEG_WANTED;
506 error = tsleep((caddr_t)shmseg, PCATCH, "shmget", 0);
511 if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
513 error = ipcperm(p, &shmseg->shm_perm, mode);
516 if (uap->size && uap->size > shmseg->shm_segsz)
518 uap->sysmsg_result = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
523 shmget_allocate_segment(struct proc *p, struct shmget_args *uap, int mode)
525 int i, segnum, shmid, size;
526 struct ucred *cred = p->p_ucred;
527 struct shmid_ds *shmseg;
528 struct shm_handle *shm_handle;
530 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
532 if (shm_nused >= shminfo.shmmni) /* any shmids left? */
534 size = round_page(uap->size);
535 if (shm_committed + btoc(size) > shminfo.shmall)
537 if (shm_last_free < 0) {
538 shmrealloc(); /* maybe expand the shmsegs[] array */
539 for (i = 0; i < shmalloced; i++)
540 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
546 segnum = shm_last_free;
549 shmseg = &shmsegs[segnum];
551 * In case we sleep in malloc(), mark the segment present but deleted
552 * so that noone else tries to create the same key.
554 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
555 shmseg->shm_perm.key = uap->key;
556 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff;
557 shm_handle = kmalloc(sizeof(struct shm_handle), M_SHM, M_WAITOK);
558 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
561 * We make sure that we have allocated a pager before we need
565 shm_handle->shm_object =
566 vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0);
568 shm_handle->shm_object =
569 vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0);
571 vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING);
572 vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT);
574 shmseg->shm_internal = shm_handle;
575 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid;
576 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid;
577 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
578 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
579 shmseg->shm_segsz = uap->size;
580 shmseg->shm_cpid = p->p_pid;
581 shmseg->shm_lpid = shmseg->shm_nattch = 0;
582 shmseg->shm_atime = shmseg->shm_dtime = 0;
583 shmseg->shm_ctime = time_second;
584 shm_committed += btoc(size);
586 if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
588 * Somebody else wanted this key while we were asleep. Wake
591 shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
592 wakeup((caddr_t)shmseg);
594 uap->sysmsg_result = shmid;
602 sys_shmget(struct shmget_args *uap)
604 struct thread *td = curthread;
605 struct proc *p = td->td_proc;
606 int segnum, mode, error;
608 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
611 mode = uap->shmflg & ACCESSPERMS;
614 if (uap->key != IPC_PRIVATE) {
616 segnum = shm_find_segment_by_key(uap->key);
618 error = shmget_existing(p, uap, mode, segnum);
623 if ((uap->shmflg & IPC_CREAT) == 0) {
628 error = shmget_allocate_segment(p, uap, mode);
635 * shmsys_args(int which, int a2, ...) (VARARGS)
640 sys_shmsys(struct shmsys_args *uap)
642 struct thread *td = curthread;
643 unsigned int which = (unsigned int)uap->which;
646 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
649 if (which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
652 bcopy(&uap->a2, &uap->which,
653 sizeof(struct shmsys_args) - offsetof(struct shmsys_args, a2));
654 error = ((*shmcalls[which])(uap));
661 shmfork(struct proc *p1, struct proc *p2)
663 struct shmmap_state *shmmap_s;
667 size = shminfo.shmseg * sizeof(struct shmmap_state);
668 shmmap_s = kmalloc(size, M_SHM, M_WAITOK);
669 bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size);
670 p2->p_vmspace->vm_shm = (caddr_t)shmmap_s;
671 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
672 if (shmmap_s->shmid != -1)
673 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++;
677 shmexit(struct vmspace *vm)
679 struct shmmap_state *base, *shm;
682 if ((base = (struct shmmap_state *)vm->vm_shm) != NULL) {
684 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) {
685 if (shm->shmid != -1)
686 shm_delete_mapping(vm, shm);
696 struct shmid_ds *newsegs;
698 if (shmalloced >= shminfo.shmmni)
701 newsegs = kmalloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
702 for (i = 0; i < shmalloced; i++)
703 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
704 for (; i < shminfo.shmmni; i++) {
705 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
706 shmsegs[i].shm_perm.seq = 0;
708 kfree(shmsegs, M_SHM);
710 shmalloced = shminfo.shmmni;
718 shminfo.shmmax = shminfo.shmall * PAGE_SIZE;
719 shmalloced = shminfo.shmmni;
720 shmsegs = kmalloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
721 for (i = 0; i < shmalloced; i++) {
722 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
723 shmsegs[i].shm_perm.seq = 0;
729 SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL);