sysv_shm.c revision 76941 
1/* $FreeBSD: head/sys/kern/sysv_shm.c 76941 2001-05-21 18:52:02Z jhb $ */
2/*	$NetBSD: sysv_shm.c,v 1.23 1994/07/04 23:25:12 glass Exp $	*/
3
4/*
5 * Copyright (c) 1994 Adam Glass and Charles Hannum.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *	This product includes software developed by Adam Glass and Charles
18 *	Hannum.
19 * 4. The names of the authors may not be used to endorse or promote products
20 *    derived from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34#include "opt_compat.h"
35#include "opt_rlimit.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/sysent.h>
51#include <sys/sysproto.h>
52#include <sys/jail.h>
53
54#include <vm/vm.h>
55#include <vm/vm_param.h>
56#include <vm/pmap.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>
61
62static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments");
63
64struct oshmctl_args;
65static int oshmctl __P((struct proc *p, struct oshmctl_args *uap));
66
67static int shmget_allocate_segment __P((struct proc *p, struct shmget_args *uap, int mode));
68static int shmget_existing __P((struct proc *p, struct shmget_args *uap, int mode, int segnum));
69
70/* XXX casting to (sy_call_t *) is bogus, as usual. */
71static sy_call_t *shmcalls[] = {
72	(sy_call_t *)shmat, (sy_call_t *)oshmctl,
73	(sy_call_t *)shmdt, (sy_call_t *)shmget,
74	(sy_call_t *)shmctl
75};
76
77#define	SHMSEG_FREE     	0x0200
78#define	SHMSEG_REMOVED  	0x0400
79#define	SHMSEG_ALLOCATED	0x0800
80#define	SHMSEG_WANTED		0x1000
81
82static int shm_last_free, shm_nused, shm_committed, shmalloced;
83static struct shmid_ds	*shmsegs;
84
85struct shm_handle {
86	/* vm_offset_t kva; */
87	vm_object_t shm_object;
88};
89
90struct shmmap_state {
91	vm_offset_t va;
92	int shmid;
93};
94
95static void shm_deallocate_segment __P((struct shmid_ds *));
96static int shm_find_segment_by_key __P((key_t));
97static struct shmid_ds *shm_find_segment_by_shmid __P((int));
98static int shm_delete_mapping __P((struct proc *, struct shmmap_state *));
99static void shmrealloc __P((void));
100static void shminit __P((void));
101static int sysvshm_modload __P((struct module *, int, void *));
102static int shmunload __P((void));
103static void shmexit_myhook __P((struct proc *p));
104static void shmfork_myhook __P((struct proc *p1, struct proc *p2));
105
106/*
107 * Tuneable values
108 */
109#ifndef SHMMAXPGS
110#define	SHMMAXPGS	8192	/* note: sysv shared memory is swap backed */
111#endif
112#ifndef SHMMAX
113#define	SHMMAX	(SHMMAXPGS*PAGE_SIZE)
114#endif
115#ifndef SHMMIN
116#define	SHMMIN	1
117#endif
118#ifndef SHMMNI
119#define	SHMMNI	192
120#endif
121#ifndef SHMSEG
122#define	SHMSEG	128
123#endif
124#ifndef SHMALL
125#define	SHMALL	(SHMMAXPGS)
126#endif
127
128struct	shminfo shminfo = {
129	SHMMAX,
130	SHMMIN,
131	SHMMNI,
132	SHMSEG,
133	SHMALL
134};
135
136static int shm_use_phys;
137
138SYSCTL_DECL(_kern_ipc);
139SYSCTL_INT(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, "");
140SYSCTL_INT(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, "");
141SYSCTL_INT(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0, "");
142SYSCTL_INT(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RD, &shminfo.shmseg, 0, "");
143SYSCTL_INT(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, "");
144SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, &shm_use_phys, 0, "");
145
146static int
147shm_find_segment_by_key(key)
148	key_t key;
149{
150	int i;
151
152	for (i = 0; i < shmalloced; i++)
153		if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) &&
154		    shmsegs[i].shm_perm.key == key)
155			return i;
156	return -1;
157}
158
159static struct shmid_ds *
160shm_find_segment_by_shmid(shmid)
161	int shmid;
162{
163	int segnum;
164	struct shmid_ds *shmseg;
165
166	segnum = IPCID_TO_IX(shmid);
167	if (segnum < 0 || segnum >= shmalloced)
168		return NULL;
169	shmseg = &shmsegs[segnum];
170	if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED))
171	    != SHMSEG_ALLOCATED ||
172	    shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid))
173		return NULL;
174	return shmseg;
175}
176
177static void
178shm_deallocate_segment(shmseg)
179	struct shmid_ds *shmseg;
180{
181	struct shm_handle *shm_handle;
182	size_t size;
183
184	shm_handle = shmseg->shm_internal;
185	mtx_lock(&vm_mtx);
186	vm_object_deallocate(shm_handle->shm_object);
187	mtx_unlock(&vm_mtx);
188	free((caddr_t)shm_handle, M_SHM);
189	shmseg->shm_internal = NULL;
190	size = round_page(shmseg->shm_segsz);
191	shm_committed -= btoc(size);
192	shm_nused--;
193	shmseg->shm_perm.mode = SHMSEG_FREE;
194}
195
196static int
197shm_delete_mapping(p, shmmap_s)
198	struct proc *p;
199	struct shmmap_state *shmmap_s;
200{
201	struct shmid_ds *shmseg;
202	int segnum, result;
203	size_t size;
204
205	segnum = IPCID_TO_IX(shmmap_s->shmid);
206	shmseg = &shmsegs[segnum];
207	size = round_page(shmseg->shm_segsz);
208	mtx_lock(&vm_mtx);
209	result = vm_map_remove(&p->p_vmspace->vm_map, shmmap_s->va, shmmap_s->va + size);
210	mtx_unlock(&vm_mtx);
211	if (result != KERN_SUCCESS)
212		return EINVAL;
213	shmmap_s->shmid = -1;
214	shmseg->shm_dtime = time_second;
215	if ((--shmseg->shm_nattch <= 0) &&
216	    (shmseg->shm_perm.mode & SHMSEG_REMOVED)) {
217		shm_deallocate_segment(shmseg);
218		shm_last_free = segnum;
219	}
220	return 0;
221}
222
223#ifndef _SYS_SYSPROTO_H_
224struct shmdt_args {
225	void *shmaddr;
226};
227#endif
228
229int
230shmdt(p, uap)
231	struct proc *p;
232	struct shmdt_args *uap;
233{
234	struct shmmap_state *shmmap_s;
235	int i;
236
237	if (!jail_sysvipc_allowed && jailed(p->p_ucred))
238		return (ENOSYS);
239
240	shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
241 	if (shmmap_s == NULL)
242 	    return EINVAL;
243	for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
244		if (shmmap_s->shmid != -1 &&
245		    shmmap_s->va == (vm_offset_t)uap->shmaddr)
246			break;
247	if (i == shminfo.shmseg)
248		return EINVAL;
249	return shm_delete_mapping(p, shmmap_s);
250}
251
252#ifndef _SYS_SYSPROTO_H_
253struct shmat_args {
254	int shmid;
255	void *shmaddr;
256	int shmflg;
257};
258#endif
259
260int
261shmat(p, uap)
262	struct proc *p;
263	struct shmat_args *uap;
264{
265	int error, i, flags;
266	struct shmid_ds *shmseg;
267	struct shmmap_state *shmmap_s = NULL;
268	struct shm_handle *shm_handle;
269	vm_offset_t attach_va;
270	vm_prot_t prot;
271	vm_size_t size;
272	int rv;
273
274	if (!jail_sysvipc_allowed && jailed(p->p_ucred))
275		return (ENOSYS);
276
277	shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
278	if (shmmap_s == NULL) {
279		size = shminfo.shmseg * sizeof(struct shmmap_state);
280		shmmap_s = malloc(size, M_SHM, M_WAITOK);
281		for (i = 0; i < shminfo.shmseg; i++)
282			shmmap_s[i].shmid = -1;
283		p->p_vmspace->vm_shm = (caddr_t)shmmap_s;
284	}
285	shmseg = shm_find_segment_by_shmid(uap->shmid);
286	if (shmseg == NULL)
287		return EINVAL;
288	error = ipcperm(p, &shmseg->shm_perm,
289	    (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
290	if (error)
291		return error;
292	for (i = 0; i < shminfo.shmseg; i++) {
293		if (shmmap_s->shmid == -1)
294			break;
295		shmmap_s++;
296	}
297	if (i >= shminfo.shmseg)
298		return EMFILE;
299	size = round_page(shmseg->shm_segsz);
300#ifdef VM_PROT_READ_IS_EXEC
301	prot = VM_PROT_READ | VM_PROT_EXECUTE;
302#else
303	prot = VM_PROT_READ;
304#endif
305	if ((uap->shmflg & SHM_RDONLY) == 0)
306		prot |= VM_PROT_WRITE;
307	flags = MAP_ANON | MAP_SHARED;
308	if (uap->shmaddr) {
309		flags |= MAP_FIXED;
310		if (uap->shmflg & SHM_RND)
311			attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1);
312		else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0)
313			attach_va = (vm_offset_t)uap->shmaddr;
314		else
315			return EINVAL;
316	} else {
317		/* This is just a hint to vm_map_find() about where to put it. */
318		attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr + MAXTSIZ + MAXDSIZ);
319	}
320
321	shm_handle = shmseg->shm_internal;
322	mtx_lock(&vm_mtx);
323	vm_object_reference(shm_handle->shm_object);
324	rv = vm_map_find(&p->p_vmspace->vm_map, shm_handle->shm_object,
325		0, &attach_va, size, (flags & MAP_FIXED)?0:1, prot, prot, 0);
326	if (rv != KERN_SUCCESS) {
327		mtx_unlock(&vm_mtx);
328		return ENOMEM;
329	}
330	vm_map_inherit(&p->p_vmspace->vm_map,
331		attach_va, attach_va + size, VM_INHERIT_SHARE);
332	mtx_unlock(&vm_mtx);
333
334	shmmap_s->va = attach_va;
335	shmmap_s->shmid = uap->shmid;
336	shmseg->shm_lpid = p->p_pid;
337	shmseg->shm_atime = time_second;
338	shmseg->shm_nattch++;
339	p->p_retval[0] = attach_va;
340	return 0;
341}
342
343struct oshmid_ds {
344	struct	ipc_perm shm_perm;	/* operation perms */
345	int	shm_segsz;		/* size of segment (bytes) */
346	ushort	shm_cpid;		/* pid, creator */
347	ushort	shm_lpid;		/* pid, last operation */
348	short	shm_nattch;		/* no. of current attaches */
349	time_t	shm_atime;		/* last attach time */
350	time_t	shm_dtime;		/* last detach time */
351	time_t	shm_ctime;		/* last change time */
352	void	*shm_handle;		/* internal handle for shm segment */
353};
354
355struct oshmctl_args {
356	int shmid;
357	int cmd;
358	struct oshmid_ds *ubuf;
359};
360
361static int
362oshmctl(p, uap)
363	struct proc *p;
364	struct oshmctl_args *uap;
365{
366#ifdef COMPAT_43
367	int error;
368	struct shmid_ds *shmseg;
369	struct oshmid_ds outbuf;
370
371	if (!jail_sysvipc_allowed && jailed(p->p_ucred))
372		return (ENOSYS);
373
374	shmseg = shm_find_segment_by_shmid(uap->shmid);
375	if (shmseg == NULL)
376		return EINVAL;
377	switch (uap->cmd) {
378	case IPC_STAT:
379		error = ipcperm(p, &shmseg->shm_perm, IPC_R);
380		if (error)
381			return error;
382		outbuf.shm_perm = shmseg->shm_perm;
383		outbuf.shm_segsz = shmseg->shm_segsz;
384		outbuf.shm_cpid = shmseg->shm_cpid;
385		outbuf.shm_lpid = shmseg->shm_lpid;
386		outbuf.shm_nattch = shmseg->shm_nattch;
387		outbuf.shm_atime = shmseg->shm_atime;
388		outbuf.shm_dtime = shmseg->shm_dtime;
389		outbuf.shm_ctime = shmseg->shm_ctime;
390		outbuf.shm_handle = shmseg->shm_internal;
391		error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf));
392		if (error)
393			return error;
394		break;
395	default:
396		/* XXX casting to (sy_call_t *) is bogus, as usual. */
397		return ((sy_call_t *)shmctl)(p, uap);
398	}
399	return 0;
400#else
401	return EINVAL;
402#endif
403}
404
405#ifndef _SYS_SYSPROTO_H_
406struct shmctl_args {
407	int shmid;
408	int cmd;
409	struct shmid_ds *buf;
410};
411#endif
412
413int
414shmctl(p, uap)
415	struct proc *p;
416	struct shmctl_args *uap;
417{
418	int error;
419	struct shmid_ds inbuf;
420	struct shmid_ds *shmseg;
421
422	if (!jail_sysvipc_allowed && jailed(p->p_ucred))
423		return (ENOSYS);
424
425	shmseg = shm_find_segment_by_shmid(uap->shmid);
426	if (shmseg == NULL)
427		return EINVAL;
428	switch (uap->cmd) {
429	case IPC_STAT:
430		error = ipcperm(p, &shmseg->shm_perm, IPC_R);
431		if (error)
432			return error;
433		error = copyout((caddr_t)shmseg, uap->buf, sizeof(inbuf));
434		if (error)
435			return error;
436		break;
437	case IPC_SET:
438		error = ipcperm(p, &shmseg->shm_perm, IPC_M);
439		if (error)
440			return error;
441		error = copyin(uap->buf, (caddr_t)&inbuf, sizeof(inbuf));
442		if (error)
443			return error;
444		shmseg->shm_perm.uid = inbuf.shm_perm.uid;
445		shmseg->shm_perm.gid = inbuf.shm_perm.gid;
446		shmseg->shm_perm.mode =
447		    (shmseg->shm_perm.mode & ~ACCESSPERMS) |
448		    (inbuf.shm_perm.mode & ACCESSPERMS);
449		shmseg->shm_ctime = time_second;
450		break;
451	case IPC_RMID:
452		error = ipcperm(p, &shmseg->shm_perm, IPC_M);
453		if (error)
454			return error;
455		shmseg->shm_perm.key = IPC_PRIVATE;
456		shmseg->shm_perm.mode |= SHMSEG_REMOVED;
457		if (shmseg->shm_nattch <= 0) {
458			shm_deallocate_segment(shmseg);
459			shm_last_free = IPCID_TO_IX(uap->shmid);
460		}
461		break;
462#if 0
463	case SHM_LOCK:
464	case SHM_UNLOCK:
465#endif
466	default:
467		return EINVAL;
468	}
469	return 0;
470}
471
472#ifndef _SYS_SYSPROTO_H_
473struct shmget_args {
474	key_t key;
475	size_t size;
476	int shmflg;
477};
478#endif
479
480static int
481shmget_existing(p, uap, mode, segnum)
482	struct proc *p;
483	struct shmget_args *uap;
484	int mode;
485	int segnum;
486{
487	struct shmid_ds *shmseg;
488	int error;
489
490	shmseg = &shmsegs[segnum];
491	if (shmseg->shm_perm.mode & SHMSEG_REMOVED) {
492		/*
493		 * This segment is in the process of being allocated.  Wait
494		 * until it's done, and look the key up again (in case the
495		 * allocation failed or it was freed).
496		 */
497		shmseg->shm_perm.mode |= SHMSEG_WANTED;
498		error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0);
499		if (error)
500			return error;
501		return EAGAIN;
502	}
503	if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
504		return EEXIST;
505	error = ipcperm(p, &shmseg->shm_perm, mode);
506	if (error)
507		return error;
508	if (uap->size && uap->size > shmseg->shm_segsz)
509		return EINVAL;
510	p->p_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
511	return 0;
512}
513
514static int
515shmget_allocate_segment(p, uap, mode)
516	struct proc *p;
517	struct shmget_args *uap;
518	int mode;
519{
520	int i, segnum, shmid, size;
521	struct ucred *cred = p->p_ucred;
522	struct shmid_ds *shmseg;
523	struct shm_handle *shm_handle;
524
525	if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
526		return EINVAL;
527	if (shm_nused >= shminfo.shmmni) /* any shmids left? */
528		return ENOSPC;
529	size = round_page(uap->size);
530	if (shm_committed + btoc(size) > shminfo.shmall)
531		return ENOMEM;
532	if (shm_last_free < 0) {
533		shmrealloc();	/* maybe expand the shmsegs[] array */
534		for (i = 0; i < shmalloced; i++)
535			if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
536				break;
537		if (i == shmalloced)
538			return ENOSPC;
539		segnum = i;
540	} else  {
541		segnum = shm_last_free;
542		shm_last_free = -1;
543	}
544	shmseg = &shmsegs[segnum];
545	/*
546	 * In case we sleep in malloc(), mark the segment present but deleted
547	 * so that noone else tries to create the same key.
548	 */
549	shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
550	shmseg->shm_perm.key = uap->key;
551	shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff;
552	shm_handle = (struct shm_handle *)
553	    malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK);
554	shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
555
556	/*
557	 * We make sure that we have allocated a pager before we need
558	 * to.
559	 */
560	mtx_lock(&vm_mtx);
561	if (shm_use_phys) {
562		shm_handle->shm_object =
563		    vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0);
564	} else {
565		shm_handle->shm_object =
566		    vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0);
567	}
568	vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING);
569	vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT);
570	mtx_unlock(&vm_mtx);
571
572	shmseg->shm_internal = shm_handle;
573	shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid;
574	shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid;
575	shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
576	    (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
577	shmseg->shm_segsz = uap->size;
578	shmseg->shm_cpid = p->p_pid;
579	shmseg->shm_lpid = shmseg->shm_nattch = 0;
580	shmseg->shm_atime = shmseg->shm_dtime = 0;
581	shmseg->shm_ctime = time_second;
582	shm_committed += btoc(size);
583	shm_nused++;
584	if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
585		/*
586		 * Somebody else wanted this key while we were asleep.  Wake
587		 * them up now.
588		 */
589		shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
590		wakeup((caddr_t)shmseg);
591	}
592	p->p_retval[0] = shmid;
593	return 0;
594}
595
596int
597shmget(p, uap)
598	struct proc *p;
599	struct shmget_args *uap;
600{
601	int segnum, mode, error;
602
603	if (!jail_sysvipc_allowed && jailed(p->p_ucred))
604		return (ENOSYS);
605
606	mode = uap->shmflg & ACCESSPERMS;
607	if (uap->key != IPC_PRIVATE) {
608	again:
609		segnum = shm_find_segment_by_key(uap->key);
610		if (segnum >= 0) {
611			error = shmget_existing(p, uap, mode, segnum);
612			if (error == EAGAIN)
613				goto again;
614			return error;
615		}
616		if ((uap->shmflg & IPC_CREAT) == 0)
617			return ENOENT;
618	}
619	return shmget_allocate_segment(p, uap, mode);
620}
621
622int
623shmsys(p, uap)
624	struct proc *p;
625	/* XXX actually varargs. */
626	struct shmsys_args /* {
627		u_int	which;
628		int	a2;
629		int	a3;
630		int	a4;
631	} */ *uap;
632{
633
634	if (!jail_sysvipc_allowed && jailed(p->p_ucred))
635		return (ENOSYS);
636
637	if (uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
638		return EINVAL;
639	return ((*shmcalls[uap->which])(p, &uap->a2));
640}
641
642static void
643shmfork_myhook(p1, p2)
644	struct proc *p1, *p2;
645{
646	struct shmmap_state *shmmap_s;
647	size_t size;
648	int i;
649
650	size = shminfo.shmseg * sizeof(struct shmmap_state);
651	shmmap_s = malloc(size, M_SHM, M_WAITOK);
652	bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size);
653	p2->p_vmspace->vm_shm = (caddr_t)shmmap_s;
654	for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
655		if (shmmap_s->shmid != -1)
656			shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++;
657}
658
659static void
660shmexit_myhook(p)
661	struct proc *p;
662{
663	struct shmmap_state *shmmap_s;
664	int i;
665
666	shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
667	for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
668		if (shmmap_s->shmid != -1)
669			shm_delete_mapping(p, shmmap_s);
670	free((caddr_t)p->p_vmspace->vm_shm, M_SHM);
671	p->p_vmspace->vm_shm = NULL;
672}
673
674static void
675shmrealloc(void)
676{
677	int i;
678	struct shmid_ds *newsegs;
679
680	if (shmalloced >= shminfo.shmmni)
681		return;
682
683	newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
684	if (newsegs == NULL)
685		return;
686	for (i = 0; i < shmalloced; i++)
687		bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
688	for (; i < shminfo.shmmni; i++) {
689		shmsegs[i].shm_perm.mode = SHMSEG_FREE;
690		shmsegs[i].shm_perm.seq = 0;
691	}
692	free(shmsegs, M_SHM);
693	shmsegs = newsegs;
694	shmalloced = shminfo.shmmni;
695}
696
697static void
698shminit()
699{
700	int i;
701
702	shmalloced = shminfo.shmmni;
703	shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
704	if (shmsegs == NULL)
705		panic("cannot allocate initial memory for sysvshm");
706	for (i = 0; i < shmalloced; i++) {
707		shmsegs[i].shm_perm.mode = SHMSEG_FREE;
708		shmsegs[i].shm_perm.seq = 0;
709	}
710	shm_last_free = 0;
711	shm_nused = 0;
712	shm_committed = 0;
713	shmexit_hook = &shmexit_myhook;
714	shmfork_hook = &shmfork_myhook;
715}
716
717static int
718shmunload()
719{
720
721	if (shm_nused > 0)
722		return (EBUSY);
723
724	free(shmsegs, M_SHM);
725	shmexit_hook = NULL;
726	shmfork_hook = NULL;
727	return (0);
728}
729
730static int
731sysvshm_modload(struct module *module, int cmd, void *arg)
732{
733	int error = 0;
734
735	switch (cmd) {
736	case MOD_LOAD:
737		shminit();
738		break;
739	case MOD_UNLOAD:
740		error = shmunload();
741		break;
742	case MOD_SHUTDOWN:
743		break;
744	default:
745		error = EINVAL;
746		break;
747	}
748	return (error);
749}
750
751static moduledata_t sysvshm_mod = {
752	"sysvshm",
753	&sysvshm_modload,
754	NULL
755};
756
757SYSCALL_MODULE_HELPER(shmsys, 4);
758SYSCALL_MODULE_HELPER(shmat, 3);
759SYSCALL_MODULE_HELPER(shmctl, 3);
760SYSCALL_MODULE_HELPER(shmdt, 1);
761SYSCALL_MODULE_HELPER(shmget, 3);
762
763DECLARE_MODULE(sysvshm, sysvshm_mod,
764	SI_SUB_SYSV_SHM, SI_ORDER_FIRST);
765MODULE_VERSION(sysvshm, 1);
766