kernel - shmid_ds structure needs to change on 64-bit :-(
[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 /*      $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_sysvipc.h"
36
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/sysproto.h>
40 #include <sys/kernel.h>
41 #include <sys/sysctl.h>
42 #include <sys/shm.h>
43 #include <sys/proc.h>
44 #include <sys/malloc.h>
45 #include <sys/mman.h>
46 #include <sys/stat.h>
47 #include <sys/sysent.h>
48 #include <sys/jail.h>
49
50 #include <sys/mplock2.h>
51
52 #include <vm/vm.h>
53 #include <vm/vm_param.h>
54 #include <sys/lock.h>
55 #include <vm/pmap.h>
56 #include <vm/vm_object.h>
57 #include <vm/vm_map.h>
58 #include <vm/vm_page.h>
59 #include <vm/vm_pager.h>
60
61 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments");
62
63 struct oshmctl_args;
64 static int sys_oshmctl (struct proc *p, struct oshmctl_args *uap);
65
66 static int shmget_allocate_segment (struct proc *p, struct shmget_args *uap, int mode);
67 static int shmget_existing (struct proc *p, struct shmget_args *uap, int mode, int segnum);
68
69 /* XXX casting to (sy_call_t *) is bogus, as usual. */
70 static sy_call_t *shmcalls[] = {
71         (sy_call_t *)sys_shmat, (sy_call_t *)sys_oshmctl,
72         (sy_call_t *)sys_shmdt, (sy_call_t *)sys_shmget,
73         (sy_call_t *)sys_shmctl
74 };
75
76 #define SHMSEG_FREE             0x0200
77 #define SHMSEG_REMOVED          0x0400
78 #define SHMSEG_ALLOCATED        0x0800
79 #define SHMSEG_WANTED           0x1000
80
81 static int shm_last_free, shm_committed, shmalloced;
82 int shm_nused;
83 static struct shmid_ds  *shmsegs;
84
85 struct shm_handle {
86         /* vm_offset_t kva; */
87         vm_object_t shm_object;
88 };
89
90 struct shmmap_state {
91         vm_offset_t va;
92         int shmid;
93 };
94
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 *);
101
102 /*
103  * Tuneable values
104  */
105 #ifndef SHMMAXPGS
106 #define SHMMAXPGS       8192    /* note: sysv shared memory is swap backed */
107 #endif
108 #ifndef SHMMAX
109 #define SHMMAX  (SHMMAXPGS*PAGE_SIZE)
110 #endif
111 #ifndef SHMMIN
112 #define SHMMIN  1
113 #endif
114 #ifndef SHMMNI
115 #define SHMMNI  192
116 #endif
117 #ifndef SHMSEG
118 #define SHMSEG  128
119 #endif
120 #ifndef SHMALL
121 #define SHMALL  (SHMMAXPGS)
122 #endif
123
124 struct  shminfo shminfo = {
125         SHMMAX,
126         SHMMIN,
127         SHMMNI,
128         SHMSEG,
129         SHMALL
130 };
131
132 static int shm_use_phys;
133
134 TUNABLE_LONG("kern.ipc.shmmin", &shminfo.shmmin);
135 TUNABLE_LONG("kern.ipc.shmmni", &shminfo.shmmni);
136 TUNABLE_LONG("kern.ipc.shmseg", &shminfo.shmseg);
137 TUNABLE_LONG("kern.ipc.shmmaxpgs", &shminfo.shmall);
138 TUNABLE_INT("kern.ipc.shm_use_phys", &shm_use_phys);
139
140 SYSCTL_LONG(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0,
141     "Max shared memory segment size");
142 SYSCTL_LONG(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0,
143     "Min shared memory segment size");
144 SYSCTL_LONG(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0,
145     "Max number of shared memory identifiers");
146 SYSCTL_LONG(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RW, &shminfo.shmseg, 0,
147     "Max shared memory segments per process");
148 SYSCTL_LONG(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0,
149     "Max pages of shared memory");
150 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, &shm_use_phys, 0,
151     "Use phys pager allocation instead of swap pager allocation");
152
153 static int
154 shm_find_segment_by_key(key_t key)
155 {
156         int i;
157
158         for (i = 0; i < shmalloced; i++)
159                 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) &&
160                     shmsegs[i].shm_perm.key == key)
161                         return i;
162         return -1;
163 }
164
165 static struct shmid_ds *
166 shm_find_segment_by_shmid(int shmid)
167 {
168         int segnum;
169         struct shmid_ds *shmseg;
170
171         segnum = IPCID_TO_IX(shmid);
172         if (segnum < 0 || segnum >= shmalloced)
173                 return NULL;
174         shmseg = &shmsegs[segnum];
175         if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED))
176             != SHMSEG_ALLOCATED ||
177             shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid))
178                 return NULL;
179         return shmseg;
180 }
181
182 static void
183 shm_deallocate_segment(struct shmid_ds *shmseg)
184 {
185         struct shm_handle *shm_handle;
186         size_t size;
187
188         shm_handle = shmseg->shm_internal;
189         vm_object_deallocate(shm_handle->shm_object);
190         kfree((caddr_t)shm_handle, M_SHM);
191         shmseg->shm_internal = NULL;
192         size = round_page(shmseg->shm_segsz);
193         shm_committed -= btoc(size);
194         shm_nused--;
195         shmseg->shm_perm.mode = SHMSEG_FREE;
196 }
197
198 static int
199 shm_delete_mapping(struct vmspace *vm, 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         result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size);
209         if (result != KERN_SUCCESS)
210                 return EINVAL;
211         shmmap_s->shmid = -1;
212         shmseg->shm_dtime = time_second;
213         if ((--shmseg->shm_nattch <= 0) &&
214             (shmseg->shm_perm.mode & SHMSEG_REMOVED)) {
215                 shm_deallocate_segment(shmseg);
216                 shm_last_free = segnum;
217         }
218         return 0;
219 }
220
221 /*
222  * MPALMOSTSAFE
223  */
224 int
225 sys_shmdt(struct shmdt_args *uap)
226 {
227         struct thread *td = curthread;
228         struct proc *p = td->td_proc;
229         struct shmmap_state *shmmap_s;
230         long i;
231         int error;
232
233         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
234                 return (ENOSYS);
235
236         get_mplock();
237         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
238         if (shmmap_s == NULL) {
239                 error = EINVAL;
240                 goto done;
241         }
242         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) {
243                 if (shmmap_s->shmid != -1 &&
244                     shmmap_s->va == (vm_offset_t)uap->shmaddr)
245                         break;
246         }
247         if (i == shminfo.shmseg)
248                 error = EINVAL;
249         else
250                 error = shm_delete_mapping(p->p_vmspace, shmmap_s);
251 done:
252         rel_mplock();
253         return (error);
254 }
255
256 /*
257  * MPALMOSTSAFE
258  */
259 int
260 sys_shmat(struct shmat_args *uap)
261 {
262         struct thread *td = curthread;
263         struct proc *p = td->td_proc;
264         int error, flags;
265         long i;
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 && td->td_ucred->cr_prison != NULL)
275                 return (ENOSYS);
276
277         get_mplock();
278 again:
279         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
280         if (shmmap_s == NULL) {
281                 size = shminfo.shmseg * sizeof(struct shmmap_state);
282                 shmmap_s = kmalloc(size, M_SHM, M_WAITOK);
283                 for (i = 0; i < shminfo.shmseg; i++)
284                         shmmap_s[i].shmid = -1;
285                 if (p->p_vmspace->vm_shm != NULL) {
286                         kfree(shmmap_s, M_SHM);
287                         goto again;
288                 }
289                 p->p_vmspace->vm_shm = (caddr_t)shmmap_s;
290         }
291         shmseg = shm_find_segment_by_shmid(uap->shmid);
292         if (shmseg == NULL) {
293                 error = EINVAL;
294                 goto done;
295         }
296         error = ipcperm(p, &shmseg->shm_perm,
297                         (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
298         if (error)
299                 goto done;
300         for (i = 0; i < shminfo.shmseg; i++) {
301                 if (shmmap_s->shmid == -1)
302                         break;
303                 shmmap_s++;
304         }
305         if (i >= shminfo.shmseg) {
306                 error = EMFILE;
307                 goto done;
308         }
309         size = round_page(shmseg->shm_segsz);
310 #ifdef VM_PROT_READ_IS_EXEC
311         prot = VM_PROT_READ | VM_PROT_EXECUTE;
312 #else
313         prot = VM_PROT_READ;
314 #endif
315         if ((uap->shmflg & SHM_RDONLY) == 0)
316                 prot |= VM_PROT_WRITE;
317         flags = MAP_ANON | MAP_SHARED;
318         if (uap->shmaddr) {
319                 flags |= MAP_FIXED;
320                 if (uap->shmflg & SHM_RND) {
321                         attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1);
322                 } else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0) {
323                         attach_va = (vm_offset_t)uap->shmaddr;
324                 } else {
325                         error = EINVAL;
326                         goto done;
327                 }
328         } else {
329                 /*
330                  * This is just a hint to vm_map_find() about where to put it.
331                  */
332                 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr + maxtsiz + maxdsiz);
333         }
334
335         shm_handle = shmseg->shm_internal;
336         vm_object_hold(shm_handle->shm_object);
337         vm_object_reference_locked(shm_handle->shm_object);
338         rv = vm_map_find(&p->p_vmspace->vm_map, 
339                          shm_handle->shm_object, 0,
340                          &attach_va,
341                          size, PAGE_SIZE,
342                          ((flags & MAP_FIXED) ? 0 : 1), 
343                          VM_MAPTYPE_NORMAL,
344                          prot, prot,
345                          0);
346         vm_object_drop(shm_handle->shm_object);
347         if (rv != KERN_SUCCESS) {
348                 vm_object_deallocate(shm_handle->shm_object);
349                 error = ENOMEM;
350                 goto done;
351         }
352         vm_map_inherit(&p->p_vmspace->vm_map,
353                        attach_va, attach_va + size, VM_INHERIT_SHARE);
354
355         KKASSERT(shmmap_s->shmid == -1);
356         shmmap_s->va = attach_va;
357         shmmap_s->shmid = uap->shmid;
358         shmseg->shm_lpid = p->p_pid;
359         shmseg->shm_atime = time_second;
360         shmseg->shm_nattch++;
361         uap->sysmsg_resultp = (void *)attach_va;
362         error = 0;
363 done:
364         rel_mplock();
365         return error;
366 }
367
368 struct oshmid_ds {
369         struct  ipc_perm shm_perm;      /* operation perms */
370         int     shm_segsz;              /* size of segment (bytes) */
371         ushort  shm_cpid;               /* pid, creator */
372         ushort  shm_lpid;               /* pid, last operation */
373         short   shm_nattch;             /* no. of current attaches */
374         time_t  shm_atime;              /* last attach time */
375         time_t  shm_dtime;              /* last detach time */
376         time_t  shm_ctime;              /* last change time */
377         void    *shm_handle;            /* internal handle for shm segment */
378 };
379
380 struct oshmctl_args {
381         struct sysmsg sysmsg;
382         int shmid;
383         int cmd;
384         struct oshmid_ds *ubuf;
385 };
386
387 /*
388  * MPALMOSTSAFE
389  */
390 static int
391 sys_oshmctl(struct proc *p, struct oshmctl_args *uap)
392 {
393 #ifdef COMPAT_43
394         struct thread *td = curthread;
395         struct shmid_ds *shmseg;
396         struct oshmid_ds outbuf;
397         int error;
398
399         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
400                 return (ENOSYS);
401
402         get_mplock();
403         shmseg = shm_find_segment_by_shmid(uap->shmid);
404         if (shmseg == NULL) {
405                 error = EINVAL;
406                 goto done;
407         }
408
409         switch (uap->cmd) {
410         case IPC_STAT:
411                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
412                 if (error)
413                         break;
414                 outbuf.shm_perm = shmseg->shm_perm;
415                 outbuf.shm_segsz = shmseg->shm_segsz;
416                 outbuf.shm_cpid = shmseg->shm_cpid;
417                 outbuf.shm_lpid = shmseg->shm_lpid;
418                 outbuf.shm_nattch = shmseg->shm_nattch;
419                 outbuf.shm_atime = shmseg->shm_atime;
420                 outbuf.shm_dtime = shmseg->shm_dtime;
421                 outbuf.shm_ctime = shmseg->shm_ctime;
422                 outbuf.shm_handle = shmseg->shm_internal;
423                 error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf));
424                 break;
425         default:
426                 /* XXX casting to (sy_call_t *) is bogus, as usual. */
427                 error = sys_shmctl((struct shmctl_args *)uap);
428         }
429 done:
430         rel_mplock();
431         return error;
432 #else
433         return EINVAL;
434 #endif
435 }
436
437 /*
438  * MPALMOSTSAFE
439  */
440 int
441 sys_shmctl(struct shmctl_args *uap)
442 {
443         struct thread *td = curthread;
444         struct proc *p = td->td_proc;
445         int error;
446         struct shmid_ds inbuf;
447         struct shmid_ds *shmseg;
448
449         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
450                 return (ENOSYS);
451
452         get_mplock();
453         shmseg = shm_find_segment_by_shmid(uap->shmid);
454         if (shmseg == NULL) {
455                 error = EINVAL;
456                 goto done;
457         }
458
459         switch (uap->cmd) {
460         case IPC_STAT:
461                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
462                 if (error == 0)
463                         error = copyout(shmseg, uap->buf, sizeof(inbuf));
464                 break;
465         case IPC_SET:
466                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
467                 if (error == 0)
468                         error = copyin(uap->buf, &inbuf, sizeof(inbuf));
469                 if (error == 0) {
470                         shmseg->shm_perm.uid = inbuf.shm_perm.uid;
471                         shmseg->shm_perm.gid = inbuf.shm_perm.gid;
472                         shmseg->shm_perm.mode =
473                             (shmseg->shm_perm.mode & ~ACCESSPERMS) |
474                             (inbuf.shm_perm.mode & ACCESSPERMS);
475                         shmseg->shm_ctime = time_second;
476                 }
477                 break;
478         case IPC_RMID:
479                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
480                 if (error == 0) {
481                         shmseg->shm_perm.key = IPC_PRIVATE;
482                         shmseg->shm_perm.mode |= SHMSEG_REMOVED;
483                         if (shmseg->shm_nattch <= 0) {
484                                 shm_deallocate_segment(shmseg);
485                                 shm_last_free = IPCID_TO_IX(uap->shmid);
486                         }
487                 }
488                 break;
489 #if 0
490         case SHM_LOCK:
491         case SHM_UNLOCK:
492 #endif
493         default:
494                 error = EINVAL;
495                 break;
496         }
497 done:
498         rel_mplock();
499         return error;
500 }
501
502 static int
503 shmget_existing(struct proc *p, struct shmget_args *uap, int mode, int segnum)
504 {
505         struct shmid_ds *shmseg;
506         int error;
507
508         shmseg = &shmsegs[segnum];
509         if (shmseg->shm_perm.mode & SHMSEG_REMOVED) {
510                 /*
511                  * This segment is in the process of being allocated.  Wait
512                  * until it's done, and look the key up again (in case the
513                  * allocation failed or it was freed).
514                  */
515                 shmseg->shm_perm.mode |= SHMSEG_WANTED;
516                 error = tsleep((caddr_t)shmseg, PCATCH, "shmget", 0);
517                 if (error)
518                         return error;
519                 return EAGAIN;
520         }
521         if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
522                 return EEXIST;
523         error = ipcperm(p, &shmseg->shm_perm, mode);
524         if (error)
525                 return error;
526         if (uap->size && uap->size > shmseg->shm_segsz)
527                 return EINVAL;
528         uap->sysmsg_result = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
529         return 0;
530 }
531
532 static int
533 shmget_allocate_segment(struct proc *p, struct shmget_args *uap, int mode)
534 {
535         int i, segnum, shmid, size;
536         struct ucred *cred = p->p_ucred;
537         struct shmid_ds *shmseg;
538         struct shm_handle *shm_handle;
539
540         if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
541                 return EINVAL;
542         if (shm_nused >= shminfo.shmmni) /* any shmids left? */
543                 return ENOSPC;
544         size = round_page(uap->size);
545         if (shm_committed + btoc(size) > shminfo.shmall)
546                 return ENOMEM;
547         if (shm_last_free < 0) {
548                 shmrealloc();   /* maybe expand the shmsegs[] array */
549                 for (i = 0; i < shmalloced; i++)
550                         if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
551                                 break;
552                 if (i == shmalloced)
553                         return ENOSPC;
554                 segnum = i;
555         } else  {
556                 segnum = shm_last_free;
557                 shm_last_free = -1;
558         }
559         shmseg = &shmsegs[segnum];
560         /*
561          * In case we sleep in malloc(), mark the segment present but deleted
562          * so that noone else tries to create the same key.
563          */
564         shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
565         shmseg->shm_perm.key = uap->key;
566         shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff;
567         shm_handle = kmalloc(sizeof(struct shm_handle), M_SHM, M_WAITOK);
568         shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
569         
570         /*
571          * We make sure that we have allocated a pager before we need
572          * to.
573          */
574         if (shm_use_phys) {
575                 shm_handle->shm_object =
576                    phys_pager_alloc(NULL, size, VM_PROT_DEFAULT, 0);
577         } else {
578                 shm_handle->shm_object =
579                    swap_pager_alloc(NULL, size, VM_PROT_DEFAULT, 0);
580         }
581         vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING);
582         vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT);
583
584         shmseg->shm_internal = shm_handle;
585         shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid;
586         shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid;
587         shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
588             (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
589         shmseg->shm_segsz = uap->size;
590         shmseg->shm_cpid = p->p_pid;
591         shmseg->shm_lpid = shmseg->shm_nattch = 0;
592         shmseg->shm_atime = shmseg->shm_dtime = 0;
593         shmseg->shm_ctime = time_second;
594         shm_committed += btoc(size);
595         shm_nused++;
596         if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
597                 /*
598                  * Somebody else wanted this key while we were asleep.  Wake
599                  * them up now.
600                  */
601                 shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
602                 wakeup((caddr_t)shmseg);
603         }
604         uap->sysmsg_result = shmid;
605         return 0;
606 }
607
608 /*
609  * MPALMOSTSAFE
610  */
611 int
612 sys_shmget(struct shmget_args *uap)
613 {
614         struct thread *td = curthread;
615         struct proc *p = td->td_proc;
616         int segnum, mode, error;
617
618         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
619                 return (ENOSYS);
620
621         mode = uap->shmflg & ACCESSPERMS;
622         get_mplock();
623
624         if (uap->key != IPC_PRIVATE) {
625         again:
626                 segnum = shm_find_segment_by_key(uap->key);
627                 if (segnum >= 0) {
628                         error = shmget_existing(p, uap, mode, segnum);
629                         if (error == EAGAIN)
630                                 goto again;
631                         goto done;
632                 }
633                 if ((uap->shmflg & IPC_CREAT) == 0) {
634                         error = ENOENT;
635                         goto done;
636                 }
637         }
638         error = shmget_allocate_segment(p, uap, mode);
639 done:
640         rel_mplock();
641         return (error);
642 }
643
644 /*
645  * shmsys_args(int which, int a2, ...) (VARARGS)
646  *
647  * MPALMOSTSAFE
648  */
649 int
650 sys_shmsys(struct shmsys_args *uap)
651 {
652         struct thread *td = curthread;
653         unsigned int which = (unsigned int)uap->which;
654         int error;
655
656         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
657                 return (ENOSYS);
658
659         if (which >= NELEM(shmcalls))
660                 return EINVAL;
661         get_mplock();
662         bcopy(&uap->a2, &uap->which,
663                 sizeof(struct shmsys_args) - offsetof(struct shmsys_args, a2));
664         error = ((*shmcalls[which])(uap));
665         rel_mplock();
666
667         return(error);
668 }
669
670 void
671 shmfork(struct proc *p1, struct proc *p2)
672 {
673         struct shmmap_state *shmmap_s;
674         size_t size;
675         int i;
676
677         size = shminfo.shmseg * sizeof(struct shmmap_state);
678         shmmap_s = kmalloc(size, M_SHM, M_WAITOK);
679         bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size);
680         p2->p_vmspace->vm_shm = (caddr_t)shmmap_s;
681         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
682                 if (shmmap_s->shmid != -1)
683                         shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++;
684 }
685
686 void
687 shmexit(struct vmspace *vm)
688 {
689         struct shmmap_state *base, *shm;
690         int i;
691
692         if ((base = (struct shmmap_state *)vm->vm_shm) != NULL) {
693                 vm->vm_shm = NULL;
694                 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) {
695                         if (shm->shmid != -1)
696                                 shm_delete_mapping(vm, shm);
697                 }
698                 kfree(base, M_SHM);
699         }
700 }
701
702 static void
703 shmrealloc(void)
704 {
705         int i;
706         struct shmid_ds *newsegs;
707
708         if (shmalloced >= shminfo.shmmni)
709                 return;
710
711         newsegs = kmalloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
712         for (i = 0; i < shmalloced; i++)
713                 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
714         for (; i < shminfo.shmmni; i++) {
715                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
716                 shmsegs[i].shm_perm.seq = 0;
717         }
718         kfree(shmsegs, M_SHM);
719         shmsegs = newsegs;
720         shmalloced = shminfo.shmmni;
721 }
722
723 static void
724 shminit(void *dummy)
725 {
726         int i;
727
728         shminfo.shmmax = shminfo.shmall * PAGE_SIZE;
729         shmalloced = shminfo.shmmni;
730         shmsegs = kmalloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
731         for (i = 0; i < shmalloced; i++) {
732                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
733                 shmsegs[i].shm_perm.seq = 0;
734         }
735         shm_last_free = 0;
736         shm_nused = 0;
737         shm_committed = 0;
738 }
739 SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL);