Ansify function declarations and fix some minor style issues.
[dragonfly.git] / sys / kern / sysv_shm.c
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 1.20 2006/12/23 23:47:54 swildner Exp $ */
3 /*      $NetBSD: sysv_shm.c,v 1.23 1994/07/04 23:25:12 glass Exp $      */
4
5 /*
6  * Copyright (c) 1994 Adam Glass and Charles Hannum.  All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
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
19  *      Hannum.
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.
22  *
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.
33  */
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/sysproto.h>
41 #include <sys/kernel.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/stat.h>
48 #include <sys/sysent.h>
49 #include <sys/jail.h>
50
51 #include <vm/vm.h>
52 #include <vm/vm_param.h>
53 #include <sys/lock.h>
54 #include <vm/pmap.h>
55 #include <vm/vm_object.h>
56 #include <vm/vm_map.h>
57 #include <vm/vm_page.h>
58 #include <vm/vm_pager.h>
59
60 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments");
61
62 struct oshmctl_args;
63 static int sys_oshmctl (struct proc *p, struct oshmctl_args *uap);
64
65 static int shmget_allocate_segment (struct proc *p, struct shmget_args *uap, int mode);
66 static int shmget_existing (struct proc *p, struct shmget_args *uap, int mode, int segnum);
67
68 /* XXX casting to (sy_call_t *) is bogus, as usual. */
69 static sy_call_t *shmcalls[] = {
70         (sy_call_t *)sys_shmat, (sy_call_t *)sys_oshmctl,
71         (sy_call_t *)sys_shmdt, (sy_call_t *)sys_shmget,
72         (sy_call_t *)sys_shmctl
73 };
74
75 #define SHMSEG_FREE             0x0200
76 #define SHMSEG_REMOVED          0x0400
77 #define SHMSEG_ALLOCATED        0x0800
78 #define SHMSEG_WANTED           0x1000
79
80 static int shm_last_free, shm_nused, shm_committed, shmalloced;
81 static struct shmid_ds  *shmsegs;
82
83 struct shm_handle {
84         /* vm_offset_t kva; */
85         vm_object_t shm_object;
86 };
87
88 struct shmmap_state {
89         vm_offset_t va;
90         int shmid;
91 };
92
93 static void shm_deallocate_segment (struct shmid_ds *);
94 static int shm_find_segment_by_key (key_t);
95 static struct shmid_ds *shm_find_segment_by_shmid (int);
96 static int shm_delete_mapping (struct vmspace *vm, struct shmmap_state *);
97 static void shmrealloc (void);
98 static void shminit (void *);
99
100 /*
101  * Tuneable values
102  */
103 #ifndef SHMMAXPGS
104 #define SHMMAXPGS       8192    /* note: sysv shared memory is swap backed */
105 #endif
106 #ifndef SHMMAX
107 #define SHMMAX  (SHMMAXPGS*PAGE_SIZE)
108 #endif
109 #ifndef SHMMIN
110 #define SHMMIN  1
111 #endif
112 #ifndef SHMMNI
113 #define SHMMNI  192
114 #endif
115 #ifndef SHMSEG
116 #define SHMSEG  128
117 #endif
118 #ifndef SHMALL
119 #define SHMALL  (SHMMAXPGS)
120 #endif
121
122 struct  shminfo shminfo = {
123         SHMMAX,
124         SHMMIN,
125         SHMMNI,
126         SHMSEG,
127         SHMALL
128 };
129
130 static int shm_use_phys;
131
132 TUNABLE_INT("kern.ipc.shmmin", &shminfo.shmmin);
133 TUNABLE_INT("kern.ipc.shmmni", &shminfo.shmmni);
134 TUNABLE_INT("kern.ipc.shmseg", &shminfo.shmseg);
135 TUNABLE_INT("kern.ipc.shmmaxpgs", &shminfo.shmall);
136 TUNABLE_INT("kern.ipc.shm_use_phys", &shm_use_phys);
137
138 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, "");
139 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, "");
140 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0, "");
141 SYSCTL_INT(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RW, &shminfo.shmseg, 0, "");
142 SYSCTL_INT(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, "");
143 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, &shm_use_phys, 0, "");
144
145 static int
146 shm_find_segment_by_key(key_t key)
147 {
148         int i;
149
150         for (i = 0; i < shmalloced; i++)
151                 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) &&
152                     shmsegs[i].shm_perm.key == key)
153                         return i;
154         return -1;
155 }
156
157 static struct shmid_ds *
158 shm_find_segment_by_shmid(int shmid)
159 {
160         int segnum;
161         struct shmid_ds *shmseg;
162
163         segnum = IPCID_TO_IX(shmid);
164         if (segnum < 0 || segnum >= shmalloced)
165                 return NULL;
166         shmseg = &shmsegs[segnum];
167         if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED))
168             != SHMSEG_ALLOCATED ||
169             shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid))
170                 return NULL;
171         return shmseg;
172 }
173
174 static void
175 shm_deallocate_segment(struct shmid_ds *shmseg)
176 {
177         struct shm_handle *shm_handle;
178         size_t size;
179
180         shm_handle = shmseg->shm_internal;
181         vm_object_deallocate(shm_handle->shm_object);
182         kfree((caddr_t)shm_handle, M_SHM);
183         shmseg->shm_internal = NULL;
184         size = round_page(shmseg->shm_segsz);
185         shm_committed -= btoc(size);
186         shm_nused--;
187         shmseg->shm_perm.mode = SHMSEG_FREE;
188 }
189
190 static int
191 shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s)
192 {
193         struct shmid_ds *shmseg;
194         int segnum, result;
195         size_t size;
196
197         segnum = IPCID_TO_IX(shmmap_s->shmid);
198         shmseg = &shmsegs[segnum];
199         size = round_page(shmseg->shm_segsz);
200         result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size);
201         if (result != KERN_SUCCESS)
202                 return EINVAL;
203         shmmap_s->shmid = -1;
204         shmseg->shm_dtime = time_second;
205         if ((--shmseg->shm_nattch <= 0) &&
206             (shmseg->shm_perm.mode & SHMSEG_REMOVED)) {
207                 shm_deallocate_segment(shmseg);
208                 shm_last_free = segnum;
209         }
210         return 0;
211 }
212
213 int
214 sys_shmdt(struct shmdt_args *uap)
215 {
216         struct proc *p = curproc;
217         struct shmmap_state *shmmap_s;
218         int i;
219
220         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
221                 return (ENOSYS);
222
223         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
224         if (shmmap_s == NULL)
225             return EINVAL;
226         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
227                 if (shmmap_s->shmid != -1 &&
228                     shmmap_s->va == (vm_offset_t)uap->shmaddr)
229                         break;
230         if (i == shminfo.shmseg)
231                 return EINVAL;
232         return shm_delete_mapping(p->p_vmspace, shmmap_s);
233 }
234
235 int
236 sys_shmat(struct shmat_args *uap)
237 {
238         struct proc *p = curproc;
239         int error, i, flags;
240         struct shmid_ds *shmseg;
241         struct shmmap_state *shmmap_s = NULL;
242         struct shm_handle *shm_handle;
243         vm_offset_t attach_va;
244         vm_prot_t prot;
245         vm_size_t size;
246         int rv;
247
248         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
249                 return (ENOSYS);
250
251         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
252         if (shmmap_s == NULL) {
253                 size = shminfo.shmseg * sizeof(struct shmmap_state);
254                 shmmap_s = kmalloc(size, M_SHM, M_WAITOK);
255                 for (i = 0; i < shminfo.shmseg; i++)
256                         shmmap_s[i].shmid = -1;
257                 p->p_vmspace->vm_shm = (caddr_t)shmmap_s;
258         }
259         shmseg = shm_find_segment_by_shmid(uap->shmid);
260         if (shmseg == NULL)
261                 return EINVAL;
262         error = ipcperm(p, &shmseg->shm_perm,
263             (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
264         if (error)
265                 return error;
266         for (i = 0; i < shminfo.shmseg; i++) {
267                 if (shmmap_s->shmid == -1)
268                         break;
269                 shmmap_s++;
270         }
271         if (i >= shminfo.shmseg)
272                 return EMFILE;
273         size = round_page(shmseg->shm_segsz);
274 #ifdef VM_PROT_READ_IS_EXEC
275         prot = VM_PROT_READ | VM_PROT_EXECUTE;
276 #else
277         prot = VM_PROT_READ;
278 #endif
279         if ((uap->shmflg & SHM_RDONLY) == 0)
280                 prot |= VM_PROT_WRITE;
281         flags = MAP_ANON | MAP_SHARED;
282         if (uap->shmaddr) {
283                 flags |= MAP_FIXED;
284                 if (uap->shmflg & SHM_RND)
285                         attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1);
286                 else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0)
287                         attach_va = (vm_offset_t)uap->shmaddr;
288                 else
289                         return EINVAL;
290         } else {
291                 /* This is just a hint to vm_map_find() about where to put it. */
292                 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr + maxtsiz + maxdsiz);
293         }
294
295         shm_handle = shmseg->shm_internal;
296         vm_object_reference(shm_handle->shm_object);
297         rv = vm_map_find(&p->p_vmspace->vm_map, 
298                          shm_handle->shm_object, 0,
299                          &attach_va, size,
300                          ((flags & MAP_FIXED) ? 0 : 1), 
301                          VM_MAPTYPE_NORMAL,
302                          prot, prot,
303                          0);
304         if (rv != KERN_SUCCESS) {
305                 vm_object_deallocate(shm_handle->shm_object);
306                 return ENOMEM;
307         }
308         vm_map_inherit(&p->p_vmspace->vm_map,
309                 attach_va, attach_va + size, VM_INHERIT_SHARE);
310
311         shmmap_s->va = attach_va;
312         shmmap_s->shmid = uap->shmid;
313         shmseg->shm_lpid = p->p_pid;
314         shmseg->shm_atime = time_second;
315         shmseg->shm_nattch++;
316         uap->sysmsg_result = attach_va;
317         return 0;
318 }
319
320 struct oshmid_ds {
321         struct  ipc_perm shm_perm;      /* operation perms */
322         int     shm_segsz;              /* size of segment (bytes) */
323         ushort  shm_cpid;               /* pid, creator */
324         ushort  shm_lpid;               /* pid, last operation */
325         short   shm_nattch;             /* no. of current attaches */
326         time_t  shm_atime;              /* last attach time */
327         time_t  shm_dtime;              /* last detach time */
328         time_t  shm_ctime;              /* last change time */
329         void    *shm_handle;            /* internal handle for shm segment */
330 };
331
332 struct oshmctl_args {
333         struct sysmsg sysmsg;
334         int shmid;
335         int cmd;
336         struct oshmid_ds *ubuf;
337 };
338
339 static int
340 sys_oshmctl(struct proc *p, struct oshmctl_args *uap)
341 {
342 #ifdef COMPAT_43
343         int error;
344         struct shmid_ds *shmseg;
345         struct oshmid_ds outbuf;
346
347         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
348                 return (ENOSYS);
349
350         shmseg = shm_find_segment_by_shmid(uap->shmid);
351         if (shmseg == NULL)
352                 return EINVAL;
353         switch (uap->cmd) {
354         case IPC_STAT:
355                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
356                 if (error)
357                         return error;
358                 outbuf.shm_perm = shmseg->shm_perm;
359                 outbuf.shm_segsz = shmseg->shm_segsz;
360                 outbuf.shm_cpid = shmseg->shm_cpid;
361                 outbuf.shm_lpid = shmseg->shm_lpid;
362                 outbuf.shm_nattch = shmseg->shm_nattch;
363                 outbuf.shm_atime = shmseg->shm_atime;
364                 outbuf.shm_dtime = shmseg->shm_dtime;
365                 outbuf.shm_ctime = shmseg->shm_ctime;
366                 outbuf.shm_handle = shmseg->shm_internal;
367                 error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf));
368                 if (error)
369                         return error;
370                 break;
371         default:
372                 /* XXX casting to (sy_call_t *) is bogus, as usual. */
373                 return (sys_shmctl((struct shmctl_args *)uap));
374         }
375         return 0;
376 #else
377         return EINVAL;
378 #endif
379 }
380
381 int
382 sys_shmctl(struct shmctl_args *uap)
383 {
384         struct proc *p = curproc;
385         int error;
386         struct shmid_ds inbuf;
387         struct shmid_ds *shmseg;
388
389         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
390                 return (ENOSYS);
391
392         shmseg = shm_find_segment_by_shmid(uap->shmid);
393         if (shmseg == NULL)
394                 return EINVAL;
395         switch (uap->cmd) {
396         case IPC_STAT:
397                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
398                 if (error)
399                         return error;
400                 error = copyout((caddr_t)shmseg, uap->buf, sizeof(inbuf));
401                 if (error)
402                         return error;
403                 break;
404         case IPC_SET:
405                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
406                 if (error)
407                         return error;
408                 error = copyin(uap->buf, (caddr_t)&inbuf, sizeof(inbuf));
409                 if (error)
410                         return error;
411                 shmseg->shm_perm.uid = inbuf.shm_perm.uid;
412                 shmseg->shm_perm.gid = inbuf.shm_perm.gid;
413                 shmseg->shm_perm.mode =
414                     (shmseg->shm_perm.mode & ~ACCESSPERMS) |
415                     (inbuf.shm_perm.mode & ACCESSPERMS);
416                 shmseg->shm_ctime = time_second;
417                 break;
418         case IPC_RMID:
419                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
420                 if (error)
421                         return error;
422                 shmseg->shm_perm.key = IPC_PRIVATE;
423                 shmseg->shm_perm.mode |= SHMSEG_REMOVED;
424                 if (shmseg->shm_nattch <= 0) {
425                         shm_deallocate_segment(shmseg);
426                         shm_last_free = IPCID_TO_IX(uap->shmid);
427                 }
428                 break;
429 #if 0
430         case SHM_LOCK:
431         case SHM_UNLOCK:
432 #endif
433         default:
434                 return EINVAL;
435         }
436         return 0;
437 }
438
439 static int
440 shmget_existing(struct proc *p, struct shmget_args *uap, int mode, int segnum)
441 {
442         struct shmid_ds *shmseg;
443         int error;
444
445         shmseg = &shmsegs[segnum];
446         if (shmseg->shm_perm.mode & SHMSEG_REMOVED) {
447                 /*
448                  * This segment is in the process of being allocated.  Wait
449                  * until it's done, and look the key up again (in case the
450                  * allocation failed or it was freed).
451                  */
452                 shmseg->shm_perm.mode |= SHMSEG_WANTED;
453                 error = tsleep((caddr_t)shmseg, PCATCH, "shmget", 0);
454                 if (error)
455                         return error;
456                 return EAGAIN;
457         }
458         if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
459                 return EEXIST;
460         error = ipcperm(p, &shmseg->shm_perm, mode);
461         if (error)
462                 return error;
463         if (uap->size && uap->size > shmseg->shm_segsz)
464                 return EINVAL;
465         uap->sysmsg_result = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
466         return 0;
467 }
468
469 static int
470 shmget_allocate_segment(struct proc *p, struct shmget_args *uap, int mode)
471 {
472         int i, segnum, shmid, size;
473         struct ucred *cred = p->p_ucred;
474         struct shmid_ds *shmseg;
475         struct shm_handle *shm_handle;
476
477         if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
478                 return EINVAL;
479         if (shm_nused >= shminfo.shmmni) /* any shmids left? */
480                 return ENOSPC;
481         size = round_page(uap->size);
482         if (shm_committed + btoc(size) > shminfo.shmall)
483                 return ENOMEM;
484         if (shm_last_free < 0) {
485                 shmrealloc();   /* maybe expand the shmsegs[] array */
486                 for (i = 0; i < shmalloced; i++)
487                         if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
488                                 break;
489                 if (i == shmalloced)
490                         return ENOSPC;
491                 segnum = i;
492         } else  {
493                 segnum = shm_last_free;
494                 shm_last_free = -1;
495         }
496         shmseg = &shmsegs[segnum];
497         /*
498          * In case we sleep in malloc(), mark the segment present but deleted
499          * so that noone else tries to create the same key.
500          */
501         shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
502         shmseg->shm_perm.key = uap->key;
503         shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff;
504         shm_handle = kmalloc(sizeof(struct shm_handle), M_SHM, M_WAITOK);
505         shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
506         
507         /*
508          * We make sure that we have allocated a pager before we need
509          * to.
510          */
511         if (shm_use_phys) {
512                 shm_handle->shm_object =
513                     vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0);
514         } else {
515                 shm_handle->shm_object =
516                     vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0);
517         }
518         vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING);
519         vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT);
520
521         shmseg->shm_internal = shm_handle;
522         shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid;
523         shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid;
524         shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
525             (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
526         shmseg->shm_segsz = uap->size;
527         shmseg->shm_cpid = p->p_pid;
528         shmseg->shm_lpid = shmseg->shm_nattch = 0;
529         shmseg->shm_atime = shmseg->shm_dtime = 0;
530         shmseg->shm_ctime = time_second;
531         shm_committed += btoc(size);
532         shm_nused++;
533         if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
534                 /*
535                  * Somebody else wanted this key while we were asleep.  Wake
536                  * them up now.
537                  */
538                 shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
539                 wakeup((caddr_t)shmseg);
540         }
541         uap->sysmsg_result = shmid;
542         return 0;
543 }
544
545 int
546 sys_shmget(struct shmget_args *uap)
547 {
548         struct proc *p = curproc;
549         int segnum, mode, error;
550
551         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
552                 return (ENOSYS);
553
554         mode = uap->shmflg & ACCESSPERMS;
555         if (uap->key != IPC_PRIVATE) {
556         again:
557                 segnum = shm_find_segment_by_key(uap->key);
558                 if (segnum >= 0) {
559                         error = shmget_existing(p, uap, mode, segnum);
560                         if (error == EAGAIN)
561                                 goto again;
562                         return error;
563                 }
564                 if ((uap->shmflg & IPC_CREAT) == 0)
565                         return ENOENT;
566         }
567         return shmget_allocate_segment(p, uap, mode);
568 }
569
570 /*
571  *  shmsys_args(int which, int a2, ...) (VARARGS)
572  */
573 int
574 sys_shmsys(struct shmsys_args *uap)
575 {
576         struct proc *p = curproc;
577         unsigned int which = (unsigned int)uap->which;
578         int error;
579
580         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
581                 return (ENOSYS);
582
583         if (which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
584                 return EINVAL;
585         bcopy(&uap->a2, &uap->which,
586                 sizeof(struct shmsys_args) - offsetof(struct shmsys_args, a2));
587         error = ((*shmcalls[which])(uap));
588         return(error);
589 }
590
591 void
592 shmfork(struct proc *p1, struct proc *p2)
593 {
594         struct shmmap_state *shmmap_s;
595         size_t size;
596         int i;
597
598         size = shminfo.shmseg * sizeof(struct shmmap_state);
599         shmmap_s = kmalloc(size, M_SHM, M_WAITOK);
600         bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size);
601         p2->p_vmspace->vm_shm = (caddr_t)shmmap_s;
602         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
603                 if (shmmap_s->shmid != -1)
604                         shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++;
605 }
606
607 void
608 shmexit(struct vmspace *vm)
609 {
610         struct shmmap_state *base, *shm;
611         int i;
612
613         if ((base = (struct shmmap_state *)vm->vm_shm) != NULL) {
614                 vm->vm_shm = NULL;
615                 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) {
616                         if (shm->shmid != -1)
617                                 shm_delete_mapping(vm, shm);
618                 }
619                 kfree(base, M_SHM);
620         }
621 }
622
623 static void
624 shmrealloc(void)
625 {
626         int i;
627         struct shmid_ds *newsegs;
628
629         if (shmalloced >= shminfo.shmmni)
630                 return;
631
632         newsegs = kmalloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
633         if (newsegs == NULL)
634                 return;
635         for (i = 0; i < shmalloced; i++)
636                 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
637         for (; i < shminfo.shmmni; i++) {
638                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
639                 shmsegs[i].shm_perm.seq = 0;
640         }
641         kfree(shmsegs, M_SHM);
642         shmsegs = newsegs;
643         shmalloced = shminfo.shmmni;
644 }
645
646 static void
647 shminit(void *dummy)
648 {
649         int i;
650
651         shminfo.shmmax = shminfo.shmall * PAGE_SIZE;
652         shmalloced = shminfo.shmmni;
653         shmsegs = kmalloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
654         if (shmsegs == NULL)
655                 panic("cannot allocate initial memory for sysvshm");
656         for (i = 0; i < shmalloced; i++) {
657                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
658                 shmsegs[i].shm_perm.seq = 0;
659         }
660         shm_last_free = 0;
661         shm_nused = 0;
662         shm_committed = 0;
663 }
664 SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL);