2 * Copyright (c) 1994 Adam Glass and Charles Hannum. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * 3. All advertising materials mentioning features or use of this software
13 * must display the following acknowledgement:
14 * This product includes software developed by Adam Glass and Charles
16 * 4. The names of the authors may not be used to endorse or promote products
17 * derived from this software without specific prior written permission.
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 #include "opt_sysvipc.h"
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/sysproto.h>
36 #include <sys/kernel.h>
37 #include <sys/sysctl.h>
40 #include <sys/malloc.h>
43 #include <sys/sysent.h>
47 #include <vm/vm_param.h>
50 #include <vm/vm_object.h>
51 #include <vm/vm_map.h>
52 #include <vm/vm_page.h>
53 #include <vm/vm_pager.h>
55 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments");
57 static int shmget_allocate_segment (struct proc *p, struct shmget_args *uap, int mode);
58 static int shmget_existing (struct proc *p, struct shmget_args *uap, int mode, int segnum);
60 #define SHMSEG_FREE 0x0200
61 #define SHMSEG_REMOVED 0x0400
62 #define SHMSEG_ALLOCATED 0x0800
63 #define SHMSEG_WANTED 0x1000
65 static int shm_last_free, shm_committed, shmalloced;
67 static struct shmid_ds *shmsegs;
68 static struct lwkt_token shm_token = LWKT_TOKEN_INITIALIZER(shm_token);
71 /* vm_offset_t kva; */
72 vm_object_t shm_object;
80 static void shm_deallocate_segment (struct shmid_ds *);
81 static int shm_find_segment_by_key (key_t);
82 static struct shmid_ds *shm_find_segment_by_shmid (int);
83 static int shm_delete_mapping (struct vmspace *vm, struct shmmap_state *);
84 static void shmrealloc (void);
85 static void shminit (void *);
100 struct shminfo shminfo = {
108 static int shm_allow_removed;
109 static int shm_use_phys = 1;
111 TUNABLE_LONG("kern.ipc.shmmin", &shminfo.shmmin);
112 TUNABLE_LONG("kern.ipc.shmmni", &shminfo.shmmni);
113 TUNABLE_LONG("kern.ipc.shmseg", &shminfo.shmseg);
114 TUNABLE_LONG("kern.ipc.shmmaxpgs", &shminfo.shmall);
115 TUNABLE_INT("kern.ipc.shm_use_phys", &shm_use_phys);
117 SYSCTL_LONG(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0,
118 "Max shared memory segment size");
119 SYSCTL_LONG(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0,
120 "Min shared memory segment size");
121 SYSCTL_LONG(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0,
122 "Max number of shared memory identifiers");
123 SYSCTL_LONG(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RW, &shminfo.shmseg, 0,
124 "Max shared memory segments per process");
125 SYSCTL_LONG(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0,
126 "Max pages of shared memory");
127 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, &shm_use_phys, 0,
128 "Use phys pager allocation instead of swap pager allocation");
129 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_allow_removed, CTLFLAG_RW,
130 &shm_allow_removed, 0,
131 "Enable/Disable attachment to attached segments marked for removal");
134 shm_find_segment_by_key(key_t key)
138 for (i = 0; i < shmalloced; i++) {
139 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) &&
140 shmsegs[i].shm_perm.key == key)
146 static struct shmid_ds *
147 shm_find_segment_by_shmid(int shmid)
150 struct shmid_ds *shmseg;
152 segnum = IPCID_TO_IX(shmid);
153 if (segnum < 0 || segnum >= shmalloced)
155 shmseg = &shmsegs[segnum];
156 if ((shmseg->shm_perm.mode & SHMSEG_ALLOCATED) == 0 ||
157 (!shm_allow_removed &&
158 (shmseg->shm_perm.mode & SHMSEG_REMOVED) != 0) ||
159 shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid)) {
166 shm_deallocate_segment(struct shmid_ds *shmseg)
168 struct shm_handle *shm_handle;
171 shm_handle = shmseg->shm_internal;
172 vm_object_deallocate(shm_handle->shm_object);
173 kfree((caddr_t)shm_handle, M_SHM);
174 shmseg->shm_internal = NULL;
175 size = round_page(shmseg->shm_segsz);
176 shm_committed -= btoc(size);
178 shmseg->shm_perm.mode = SHMSEG_FREE;
182 shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s)
184 struct shmid_ds *shmseg;
188 segnum = IPCID_TO_IX(shmmap_s->shmid);
189 shmseg = &shmsegs[segnum];
190 size = round_page(shmseg->shm_segsz);
191 result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size);
192 if (result != KERN_SUCCESS)
194 shmmap_s->shmid = -1;
195 shmseg->shm_dtime = time_second;
196 if ((--shmseg->shm_nattch <= 0) &&
197 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) {
198 shm_deallocate_segment(shmseg);
199 shm_last_free = segnum;
208 sys_shmdt(struct shmdt_args *uap)
210 struct thread *td = curthread;
211 struct proc *p = td->td_proc;
212 struct shmmap_state *shmmap_s;
216 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
219 lwkt_gettoken(&shm_token);
220 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
221 if (shmmap_s == NULL) {
225 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) {
226 if (shmmap_s->shmid != -1 &&
227 shmmap_s->va == (vm_offset_t)uap->shmaddr)
230 if (i == shminfo.shmseg)
233 error = shm_delete_mapping(p->p_vmspace, shmmap_s);
235 lwkt_reltoken(&shm_token);
244 sys_shmat(struct shmat_args *uap)
246 struct thread *td = curthread;
247 struct proc *p = td->td_proc;
250 struct shmid_ds *shmseg;
251 struct shmmap_state *shmmap_s = NULL;
252 struct shm_handle *shm_handle;
253 vm_offset_t attach_va;
259 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
262 lwkt_gettoken(&shm_token);
264 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
265 if (shmmap_s == NULL) {
266 size = shminfo.shmseg * sizeof(struct shmmap_state);
267 shmmap_s = kmalloc(size, M_SHM, M_WAITOK);
268 for (i = 0; i < shminfo.shmseg; i++)
269 shmmap_s[i].shmid = -1;
270 if (p->p_vmspace->vm_shm != NULL) {
271 kfree(shmmap_s, M_SHM);
274 p->p_vmspace->vm_shm = (caddr_t)shmmap_s;
276 shmseg = shm_find_segment_by_shmid(uap->shmid);
277 if (shmseg == NULL) {
281 error = ipcperm(p, &shmseg->shm_perm,
282 (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
285 for (i = 0; i < shminfo.shmseg; i++) {
286 if (shmmap_s->shmid == -1)
290 if (i >= shminfo.shmseg) {
294 size = round_page(shmseg->shm_segsz);
295 #ifdef VM_PROT_READ_IS_EXEC
296 prot = VM_PROT_READ | VM_PROT_EXECUTE;
300 if ((uap->shmflg & SHM_RDONLY) == 0)
301 prot |= VM_PROT_WRITE;
302 flags = MAP_ANON | MAP_SHARED;
305 if (uap->shmflg & SHM_RND) {
306 attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1);
307 } else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0) {
308 attach_va = (vm_offset_t)uap->shmaddr;
315 * This is just a hint to vm_map_find() about where to put it.
317 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr +
322 * Handle alignment. For large memory maps it is possible
323 * that the MMU can optimize the page table so align anything
324 * that is a multiple of SEG_SIZE to SEG_SIZE.
326 if ((flags & MAP_FIXED) == 0 && (size & SEG_MASK) == 0)
331 shm_handle = shmseg->shm_internal;
332 vm_object_hold(shm_handle->shm_object);
333 vm_object_chain_wait(shm_handle->shm_object, 0);
334 vm_object_reference_locked(shm_handle->shm_object);
335 rv = vm_map_find(&p->p_vmspace->vm_map,
336 shm_handle->shm_object, NULL,
339 ((flags & MAP_FIXED) ? 0 : 1),
340 VM_MAPTYPE_NORMAL, VM_SUBSYS_SHMEM,
342 vm_object_drop(shm_handle->shm_object);
343 if (rv != KERN_SUCCESS) {
344 vm_object_deallocate(shm_handle->shm_object);
348 vm_map_inherit(&p->p_vmspace->vm_map,
349 attach_va, attach_va + size, VM_INHERIT_SHARE);
351 KKASSERT(shmmap_s->shmid == -1);
352 shmmap_s->va = attach_va;
353 shmmap_s->shmid = uap->shmid;
354 shmseg->shm_lpid = p->p_pid;
355 shmseg->shm_atime = time_second;
356 shmseg->shm_nattch++;
357 uap->sysmsg_resultp = (void *)attach_va;
360 lwkt_reltoken(&shm_token);
369 sys_shmctl(struct shmctl_args *uap)
371 struct thread *td = curthread;
372 struct proc *p = td->td_proc;
374 struct shmid_ds inbuf;
375 struct shmid_ds *shmseg;
377 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
380 lwkt_gettoken(&shm_token);
381 shmseg = shm_find_segment_by_shmid(uap->shmid);
382 if (shmseg == NULL) {
389 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
391 error = copyout(shmseg, uap->buf, sizeof(inbuf));
394 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
396 error = copyin(uap->buf, &inbuf, sizeof(inbuf));
398 shmseg->shm_perm.uid = inbuf.shm_perm.uid;
399 shmseg->shm_perm.gid = inbuf.shm_perm.gid;
400 shmseg->shm_perm.mode =
401 (shmseg->shm_perm.mode & ~ACCESSPERMS) |
402 (inbuf.shm_perm.mode & ACCESSPERMS);
403 shmseg->shm_ctime = time_second;
407 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
409 shmseg->shm_perm.key = IPC_PRIVATE;
410 shmseg->shm_perm.mode |= SHMSEG_REMOVED;
411 if (shmseg->shm_nattch <= 0) {
412 shm_deallocate_segment(shmseg);
413 shm_last_free = IPCID_TO_IX(uap->shmid);
426 lwkt_reltoken(&shm_token);
432 shmget_existing(struct proc *p, struct shmget_args *uap, int mode, int segnum)
434 struct shmid_ds *shmseg;
437 shmseg = &shmsegs[segnum];
438 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) {
440 * This segment is in the process of being allocated. Wait
441 * until it's done, and look the key up again (in case the
442 * allocation failed or it was freed).
444 shmseg->shm_perm.mode |= SHMSEG_WANTED;
445 error = tsleep((caddr_t)shmseg, PCATCH, "shmget", 0);
450 if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
452 error = ipcperm(p, &shmseg->shm_perm, mode);
455 if (uap->size && uap->size > shmseg->shm_segsz)
457 uap->sysmsg_result = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
462 shmget_allocate_segment(struct proc *p, struct shmget_args *uap, int mode)
464 int i, segnum, shmid;
466 struct ucred *cred = p->p_ucred;
467 struct shmid_ds *shmseg;
468 struct shm_handle *shm_handle;
470 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
472 if (shm_nused >= shminfo.shmmni) /* any shmids left? */
474 size = round_page(uap->size);
475 if (shm_committed + btoc(size) > shminfo.shmall)
477 if (shm_last_free < 0) {
478 shmrealloc(); /* maybe expand the shmsegs[] array */
479 for (i = 0; i < shmalloced; i++) {
480 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
487 segnum = shm_last_free;
490 shmseg = &shmsegs[segnum];
492 * In case we sleep in malloc(), mark the segment present but deleted
493 * so that noone else tries to create the same key.
495 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
496 shmseg->shm_perm.key = uap->key;
497 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff;
498 shm_handle = kmalloc(sizeof(struct shm_handle), M_SHM, M_WAITOK);
499 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
502 * We make sure that we have allocated a pager before we need
506 shm_handle->shm_object =
507 phys_pager_alloc(NULL, size, VM_PROT_DEFAULT, 0);
509 shm_handle->shm_object =
510 swap_pager_alloc(NULL, size, VM_PROT_DEFAULT, 0);
512 vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING);
513 vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT);
515 shmseg->shm_internal = shm_handle;
516 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid;
517 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid;
518 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
519 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
520 shmseg->shm_segsz = uap->size;
521 shmseg->shm_cpid = p->p_pid;
522 shmseg->shm_lpid = shmseg->shm_nattch = 0;
523 shmseg->shm_atime = shmseg->shm_dtime = 0;
524 shmseg->shm_ctime = time_second;
525 shm_committed += btoc(size);
529 * If a physical mapping is desired and we have a ton of free pages
530 * we pre-allocate the pages here in order to avoid on-the-fly
531 * allocation later. This has a big effect on database warm-up
532 * times since DFly supports concurrent page faults coming from the
533 * same VM object for pages which already exist.
535 * This can hang the kernel for a while so only do it if shm_use_phys
536 * is set to 2 or higher.
538 if (shm_use_phys > 1) {
539 vm_pindex_t pi, pmax;
542 pmax = round_page(shmseg->shm_segsz) >> PAGE_SHIFT;
543 vm_object_hold(shm_handle->shm_object);
544 if (pmax > vmstats.v_free_count)
545 pmax = vmstats.v_free_count;
546 for (pi = 0; pi < pmax; ++pi) {
547 m = vm_page_grab(shm_handle->shm_object, pi,
548 VM_ALLOC_SYSTEM | VM_ALLOC_NULL_OK |
552 vm_pager_get_page(shm_handle->shm_object, &m, 1);
557 vm_object_drop(shm_handle->shm_object);
560 if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
562 * Somebody else wanted this key while we were asleep. Wake
565 shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
566 wakeup((caddr_t)shmseg);
568 uap->sysmsg_result = shmid;
576 sys_shmget(struct shmget_args *uap)
578 struct thread *td = curthread;
579 struct proc *p = td->td_proc;
580 int segnum, mode, error;
582 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
585 mode = uap->shmflg & ACCESSPERMS;
587 lwkt_gettoken(&shm_token);
589 if (uap->key != IPC_PRIVATE) {
591 segnum = shm_find_segment_by_key(uap->key);
593 error = shmget_existing(p, uap, mode, segnum);
598 if ((uap->shmflg & IPC_CREAT) == 0) {
603 error = shmget_allocate_segment(p, uap, mode);
605 lwkt_reltoken(&shm_token);
611 shmfork(struct proc *p1, struct proc *p2)
613 struct shmmap_state *shmmap_s;
617 lwkt_gettoken(&shm_token);
618 size = shminfo.shmseg * sizeof(struct shmmap_state);
619 shmmap_s = kmalloc(size, M_SHM, M_WAITOK);
620 bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size);
621 p2->p_vmspace->vm_shm = (caddr_t)shmmap_s;
622 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) {
623 if (shmmap_s->shmid != -1)
624 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++;
626 lwkt_reltoken(&shm_token);
630 shmexit(struct vmspace *vm)
632 struct shmmap_state *base, *shm;
635 if ((base = (struct shmmap_state *)vm->vm_shm) != NULL) {
637 lwkt_gettoken(&shm_token);
638 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) {
639 if (shm->shmid != -1)
640 shm_delete_mapping(vm, shm);
643 lwkt_reltoken(&shm_token);
651 struct shmid_ds *newsegs;
653 if (shmalloced >= shminfo.shmmni)
656 newsegs = kmalloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
657 for (i = 0; i < shmalloced; i++)
658 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
659 for (; i < shminfo.shmmni; i++) {
660 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
661 shmsegs[i].shm_perm.seq = 0;
663 kfree(shmsegs, M_SHM);
665 shmalloced = shminfo.shmmni;
674 * If not overridden by a tunable set the maximum shm to
675 * 2/3 of main memory.
677 if (shminfo.shmall == 0)
678 shminfo.shmall = (size_t)vmstats.v_page_count * 2 / 3;
680 shminfo.shmmax = shminfo.shmall * PAGE_SIZE;
681 shmalloced = shminfo.shmmni;
682 shmsegs = kmalloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
683 for (i = 0; i < shmalloced; i++) {
684 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
685 shmsegs[i].shm_perm.seq = 0;
691 SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL);