026d45761467f56e5ce7421145d3a731fe796c5b
[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 1.21 2008/01/06 16:55:51 swildner Exp $ */
3 /*      $NetBSD: sysv_shm.c,v 1.23 1994/07/04 23:25:12 glass Exp $      */
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 <sys/mplock2.h>
52
53 #include <vm/vm.h>
54 #include <vm/vm_param.h>
55 #include <sys/lock.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
62 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments");
63
64 struct oshmctl_args;
65 static int sys_oshmctl (struct proc *p, struct oshmctl_args *uap);
66
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);
69
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
75 };
76
77 #define SHMSEG_FREE             0x0200
78 #define SHMSEG_REMOVED          0x0400
79 #define SHMSEG_ALLOCATED        0x0800
80 #define SHMSEG_WANTED           0x1000
81
82 static int shm_last_free, shm_committed, shmalloced;
83 int shm_nused;
84 static struct shmid_ds  *shmsegs;
85
86 struct shm_handle {
87         /* vm_offset_t kva; */
88         vm_object_t shm_object;
89 };
90
91 struct shmmap_state {
92         vm_offset_t va;
93         int shmid;
94 };
95
96 static void shm_deallocate_segment (struct shmid_ds *);
97 static int shm_find_segment_by_key (key_t);
98 static struct shmid_ds *shm_find_segment_by_shmid (int);
99 static int shm_delete_mapping (struct vmspace *vm, struct shmmap_state *);
100 static void shmrealloc (void);
101 static void shminit (void *);
102
103 /*
104  * Tuneable values
105  */
106 #ifndef SHMMAXPGS
107 #define SHMMAXPGS       8192    /* note: sysv shared memory is swap backed */
108 #endif
109 #ifndef SHMMAX
110 #define SHMMAX  (SHMMAXPGS*PAGE_SIZE)
111 #endif
112 #ifndef SHMMIN
113 #define SHMMIN  1
114 #endif
115 #ifndef SHMMNI
116 #define SHMMNI  192
117 #endif
118 #ifndef SHMSEG
119 #define SHMSEG  128
120 #endif
121 #ifndef SHMALL
122 #define SHMALL  (SHMMAXPGS)
123 #endif
124
125 struct  shminfo shminfo = {
126         SHMMAX,
127         SHMMIN,
128         SHMMNI,
129         SHMSEG,
130         SHMALL
131 };
132
133 static int shm_use_phys;
134
135 TUNABLE_INT("kern.ipc.shmmin", &shminfo.shmmin);
136 TUNABLE_INT("kern.ipc.shmmni", &shminfo.shmmni);
137 TUNABLE_INT("kern.ipc.shmseg", &shminfo.shmseg);
138 TUNABLE_INT("kern.ipc.shmmaxpgs", &shminfo.shmall);
139 TUNABLE_INT("kern.ipc.shm_use_phys", &shm_use_phys);
140
141 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, "");
142 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, "");
143 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0, "");
144 SYSCTL_INT(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RW, &shminfo.shmseg, 0, "");
145 SYSCTL_INT(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, "");
146 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, &shm_use_phys, 0, "");
147
148 static int
149 shm_find_segment_by_key(key_t key)
150 {
151         int i;
152
153         for (i = 0; i < shmalloced; i++)
154                 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) &&
155                     shmsegs[i].shm_perm.key == key)
156                         return i;
157         return -1;
158 }
159
160 static struct shmid_ds *
161 shm_find_segment_by_shmid(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
177 static void
178 shm_deallocate_segment(struct shmid_ds *shmseg)
179 {
180         struct shm_handle *shm_handle;
181         size_t size;
182
183         shm_handle = shmseg->shm_internal;
184         vm_object_deallocate(shm_handle->shm_object);
185         kfree((caddr_t)shm_handle, M_SHM);
186         shmseg->shm_internal = NULL;
187         size = round_page(shmseg->shm_segsz);
188         shm_committed -= btoc(size);
189         shm_nused--;
190         shmseg->shm_perm.mode = SHMSEG_FREE;
191 }
192
193 static int
194 shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s)
195 {
196         struct shmid_ds *shmseg;
197         int segnum, result;
198         size_t size;
199
200         segnum = IPCID_TO_IX(shmmap_s->shmid);
201         shmseg = &shmsegs[segnum];
202         size = round_page(shmseg->shm_segsz);
203         result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size);
204         if (result != KERN_SUCCESS)
205                 return EINVAL;
206         shmmap_s->shmid = -1;
207         shmseg->shm_dtime = time_second;
208         if ((--shmseg->shm_nattch <= 0) &&
209             (shmseg->shm_perm.mode & SHMSEG_REMOVED)) {
210                 shm_deallocate_segment(shmseg);
211                 shm_last_free = segnum;
212         }
213         return 0;
214 }
215
216 /*
217  * MPALMOSTSAFE
218  */
219 int
220 sys_shmdt(struct shmdt_args *uap)
221 {
222         struct thread *td = curthread;
223         struct proc *p = td->td_proc;
224         struct shmmap_state *shmmap_s;
225         int i;
226         int error;
227
228         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
229                 return (ENOSYS);
230
231         get_mplock();
232         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
233         if (shmmap_s == NULL) {
234                 error = EINVAL;
235                 goto done;
236         }
237         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) {
238                 if (shmmap_s->shmid != -1 &&
239                     shmmap_s->va == (vm_offset_t)uap->shmaddr)
240                         break;
241         }
242         if (i == shminfo.shmseg)
243                 error = EINVAL;
244         else
245                 error = shm_delete_mapping(p->p_vmspace, shmmap_s);
246 done:
247         rel_mplock();
248         return (error);
249 }
250
251 /*
252  * MPALMOSTSAFE
253  */
254 int
255 sys_shmat(struct shmat_args *uap)
256 {
257         struct thread *td = curthread;
258         struct proc *p = td->td_proc;
259         int error, i, flags;
260         struct shmid_ds *shmseg;
261         struct shmmap_state *shmmap_s = NULL;
262         struct shm_handle *shm_handle;
263         vm_offset_t attach_va;
264         vm_prot_t prot;
265         vm_size_t size;
266         int rv;
267
268         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
269                 return (ENOSYS);
270
271         get_mplock();
272 again:
273         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
274         if (shmmap_s == NULL) {
275                 size = shminfo.shmseg * sizeof(struct shmmap_state);
276                 shmmap_s = kmalloc(size, M_SHM, M_WAITOK);
277                 for (i = 0; i < shminfo.shmseg; i++)
278                         shmmap_s[i].shmid = -1;
279                 if (p->p_vmspace->vm_shm != NULL) {
280                         kfree(shmmap_s, M_SHM);
281                         goto again;
282                 }
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                 error = EINVAL;
288                 goto done;
289         }
290         error = ipcperm(p, &shmseg->shm_perm,
291                         (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
292         if (error)
293                 goto done;
294         for (i = 0; i < shminfo.shmseg; i++) {
295                 if (shmmap_s->shmid == -1)
296                         break;
297                 shmmap_s++;
298         }
299         if (i >= shminfo.shmseg) {
300                 error = EMFILE;
301                 goto done;
302         }
303         size = round_page(shmseg->shm_segsz);
304 #ifdef VM_PROT_READ_IS_EXEC
305         prot = VM_PROT_READ | VM_PROT_EXECUTE;
306 #else
307         prot = VM_PROT_READ;
308 #endif
309         if ((uap->shmflg & SHM_RDONLY) == 0)
310                 prot |= VM_PROT_WRITE;
311         flags = MAP_ANON | MAP_SHARED;
312         if (uap->shmaddr) {
313                 flags |= MAP_FIXED;
314                 if (uap->shmflg & SHM_RND) {
315                         attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1);
316                 } else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0) {
317                         attach_va = (vm_offset_t)uap->shmaddr;
318                 } else {
319                         error = EINVAL;
320                         goto done;
321                 }
322         } else {
323                 /*
324                  * This is just a hint to vm_map_find() about where to put it.
325                  */
326                 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr + maxtsiz + maxdsiz);
327         }
328
329         shm_handle = shmseg->shm_internal;
330         vm_object_reference(shm_handle->shm_object);
331         rv = vm_map_find(&p->p_vmspace->vm_map, 
332                          shm_handle->shm_object, 0,
333                          &attach_va,
334                          size, PAGE_SIZE,
335                          ((flags & MAP_FIXED) ? 0 : 1), 
336                          VM_MAPTYPE_NORMAL,
337                          prot, prot,
338                          0);
339         if (rv != KERN_SUCCESS) {
340                 vm_object_deallocate(shm_handle->shm_object);
341                 error = ENOMEM;
342                 goto done;
343         }
344         vm_map_inherit(&p->p_vmspace->vm_map,
345                        attach_va, attach_va + size, VM_INHERIT_SHARE);
346
347         KKASSERT(shmmap_s->shmid == -1);
348         shmmap_s->va = attach_va;
349         shmmap_s->shmid = uap->shmid;
350         shmseg->shm_lpid = p->p_pid;
351         shmseg->shm_atime = time_second;
352         shmseg->shm_nattch++;
353         uap->sysmsg_resultp = (void *)attach_va;
354         error = 0;
355 done:
356         rel_mplock();
357         return error;
358 }
359
360 struct oshmid_ds {
361         struct  ipc_perm shm_perm;      /* operation perms */
362         int     shm_segsz;              /* size of segment (bytes) */
363         ushort  shm_cpid;               /* pid, creator */
364         ushort  shm_lpid;               /* pid, last operation */
365         short   shm_nattch;             /* no. of current attaches */
366         time_t  shm_atime;              /* last attach time */
367         time_t  shm_dtime;              /* last detach time */
368         time_t  shm_ctime;              /* last change time */
369         void    *shm_handle;            /* internal handle for shm segment */
370 };
371
372 struct oshmctl_args {
373         struct sysmsg sysmsg;
374         int shmid;
375         int cmd;
376         struct oshmid_ds *ubuf;
377 };
378
379 /*
380  * MPALMOSTSAFE
381  */
382 static int
383 sys_oshmctl(struct proc *p, struct oshmctl_args *uap)
384 {
385 #ifdef COMPAT_43
386         struct thread *td = curthread;
387         struct shmid_ds *shmseg;
388         struct oshmid_ds outbuf;
389         int error;
390
391         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
392                 return (ENOSYS);
393
394         get_mplock();
395         shmseg = shm_find_segment_by_shmid(uap->shmid);
396         if (shmseg == NULL) {
397                 error = EINVAL;
398                 goto done;
399         }
400
401         switch (uap->cmd) {
402         case IPC_STAT:
403                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
404                 if (error)
405                         break;
406                 outbuf.shm_perm = shmseg->shm_perm;
407                 outbuf.shm_segsz = shmseg->shm_segsz;
408                 outbuf.shm_cpid = shmseg->shm_cpid;
409                 outbuf.shm_lpid = shmseg->shm_lpid;
410                 outbuf.shm_nattch = shmseg->shm_nattch;
411                 outbuf.shm_atime = shmseg->shm_atime;
412                 outbuf.shm_dtime = shmseg->shm_dtime;
413                 outbuf.shm_ctime = shmseg->shm_ctime;
414                 outbuf.shm_handle = shmseg->shm_internal;
415                 error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf));
416                 break;
417         default:
418                 /* XXX casting to (sy_call_t *) is bogus, as usual. */
419                 error = sys_shmctl((struct shmctl_args *)uap);
420         }
421 done:
422         rel_mplock();
423         return error;
424 #else
425         return EINVAL;
426 #endif
427 }
428
429 /*
430  * MPALMOSTSAFE
431  */
432 int
433 sys_shmctl(struct shmctl_args *uap)
434 {
435         struct thread *td = curthread;
436         struct proc *p = td->td_proc;
437         int error;
438         struct shmid_ds inbuf;
439         struct shmid_ds *shmseg;
440
441         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
442                 return (ENOSYS);
443
444         get_mplock();
445         shmseg = shm_find_segment_by_shmid(uap->shmid);
446         if (shmseg == NULL) {
447                 error = EINVAL;
448                 goto done;
449         }
450
451         switch (uap->cmd) {
452         case IPC_STAT:
453                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
454                 if (error == 0)
455                         error = copyout(shmseg, uap->buf, sizeof(inbuf));
456                 break;
457         case IPC_SET:
458                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
459                 if (error == 0)
460                         error = copyin(uap->buf, &inbuf, sizeof(inbuf));
461                 if (error == 0) {
462                         shmseg->shm_perm.uid = inbuf.shm_perm.uid;
463                         shmseg->shm_perm.gid = inbuf.shm_perm.gid;
464                         shmseg->shm_perm.mode =
465                             (shmseg->shm_perm.mode & ~ACCESSPERMS) |
466                             (inbuf.shm_perm.mode & ACCESSPERMS);
467                         shmseg->shm_ctime = time_second;
468                 }
469                 break;
470         case IPC_RMID:
471                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
472                 if (error == 0) {
473                         shmseg->shm_perm.key = IPC_PRIVATE;
474                         shmseg->shm_perm.mode |= SHMSEG_REMOVED;
475                         if (shmseg->shm_nattch <= 0) {
476                                 shm_deallocate_segment(shmseg);
477                                 shm_last_free = IPCID_TO_IX(uap->shmid);
478                         }
479                 }
480                 break;
481 #if 0
482         case SHM_LOCK:
483         case SHM_UNLOCK:
484 #endif
485         default:
486                 error = EINVAL;
487                 break;
488         }
489 done:
490         rel_mplock();
491         return error;
492 }
493
494 static int
495 shmget_existing(struct proc *p, struct shmget_args *uap, int mode, int segnum)
496 {
497         struct shmid_ds *shmseg;
498         int error;
499
500         shmseg = &shmsegs[segnum];
501         if (shmseg->shm_perm.mode & SHMSEG_REMOVED) {
502                 /*
503                  * This segment is in the process of being allocated.  Wait
504                  * until it's done, and look the key up again (in case the
505                  * allocation failed or it was freed).
506                  */
507                 shmseg->shm_perm.mode |= SHMSEG_WANTED;
508                 error = tsleep((caddr_t)shmseg, PCATCH, "shmget", 0);
509                 if (error)
510                         return error;
511                 return EAGAIN;
512         }
513         if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
514                 return EEXIST;
515         error = ipcperm(p, &shmseg->shm_perm, mode);
516         if (error)
517                 return error;
518         if (uap->size && uap->size > shmseg->shm_segsz)
519                 return EINVAL;
520         uap->sysmsg_result = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
521         return 0;
522 }
523
524 static int
525 shmget_allocate_segment(struct proc *p, struct shmget_args *uap, int mode)
526 {
527         int i, segnum, shmid, size;
528         struct ucred *cred = p->p_ucred;
529         struct shmid_ds *shmseg;
530         struct shm_handle *shm_handle;
531
532         if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
533                 return EINVAL;
534         if (shm_nused >= shminfo.shmmni) /* any shmids left? */
535                 return ENOSPC;
536         size = round_page(uap->size);
537         if (shm_committed + btoc(size) > shminfo.shmall)
538                 return ENOMEM;
539         if (shm_last_free < 0) {
540                 shmrealloc();   /* maybe expand the shmsegs[] array */
541                 for (i = 0; i < shmalloced; i++)
542                         if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
543                                 break;
544                 if (i == shmalloced)
545                         return ENOSPC;
546                 segnum = i;
547         } else  {
548                 segnum = shm_last_free;
549                 shm_last_free = -1;
550         }
551         shmseg = &shmsegs[segnum];
552         /*
553          * In case we sleep in malloc(), mark the segment present but deleted
554          * so that noone else tries to create the same key.
555          */
556         shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
557         shmseg->shm_perm.key = uap->key;
558         shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff;
559         shm_handle = kmalloc(sizeof(struct shm_handle), M_SHM, M_WAITOK);
560         shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
561         
562         /*
563          * We make sure that we have allocated a pager before we need
564          * to.
565          */
566         if (shm_use_phys) {
567                 shm_handle->shm_object =
568                    phys_pager_alloc(NULL, size, VM_PROT_DEFAULT, 0);
569         } else {
570                 shm_handle->shm_object =
571                    swap_pager_alloc(NULL, size, VM_PROT_DEFAULT, 0);
572         }
573         vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING);
574         vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT);
575
576         shmseg->shm_internal = shm_handle;
577         shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid;
578         shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid;
579         shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
580             (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
581         shmseg->shm_segsz = uap->size;
582         shmseg->shm_cpid = p->p_pid;
583         shmseg->shm_lpid = shmseg->shm_nattch = 0;
584         shmseg->shm_atime = shmseg->shm_dtime = 0;
585         shmseg->shm_ctime = time_second;
586         shm_committed += btoc(size);
587         shm_nused++;
588         if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
589                 /*
590                  * Somebody else wanted this key while we were asleep.  Wake
591                  * them up now.
592                  */
593                 shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
594                 wakeup((caddr_t)shmseg);
595         }
596         uap->sysmsg_result = shmid;
597         return 0;
598 }
599
600 /*
601  * MPALMOSTSAFE
602  */
603 int
604 sys_shmget(struct shmget_args *uap)
605 {
606         struct thread *td = curthread;
607         struct proc *p = td->td_proc;
608         int segnum, mode, error;
609
610         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
611                 return (ENOSYS);
612
613         mode = uap->shmflg & ACCESSPERMS;
614         get_mplock();
615
616         if (uap->key != IPC_PRIVATE) {
617         again:
618                 segnum = shm_find_segment_by_key(uap->key);
619                 if (segnum >= 0) {
620                         error = shmget_existing(p, uap, mode, segnum);
621                         if (error == EAGAIN)
622                                 goto again;
623                         goto done;
624                 }
625                 if ((uap->shmflg & IPC_CREAT) == 0) {
626                         error = ENOENT;
627                         goto done;
628                 }
629         }
630         error = shmget_allocate_segment(p, uap, mode);
631 done:
632         rel_mplock();
633         return (error);
634 }
635
636 /*
637  * shmsys_args(int which, int a2, ...) (VARARGS)
638  *
639  * MPALMOSTSAFE
640  */
641 int
642 sys_shmsys(struct shmsys_args *uap)
643 {
644         struct thread *td = curthread;
645         unsigned int which = (unsigned int)uap->which;
646         int error;
647
648         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
649                 return (ENOSYS);
650
651         if (which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
652                 return EINVAL;
653         get_mplock();
654         bcopy(&uap->a2, &uap->which,
655                 sizeof(struct shmsys_args) - offsetof(struct shmsys_args, a2));
656         error = ((*shmcalls[which])(uap));
657         rel_mplock();
658
659         return(error);
660 }
661
662 void
663 shmfork(struct proc *p1, struct proc *p2)
664 {
665         struct shmmap_state *shmmap_s;
666         size_t size;
667         int i;
668
669         size = shminfo.shmseg * sizeof(struct shmmap_state);
670         shmmap_s = kmalloc(size, M_SHM, M_WAITOK);
671         bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size);
672         p2->p_vmspace->vm_shm = (caddr_t)shmmap_s;
673         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
674                 if (shmmap_s->shmid != -1)
675                         shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++;
676 }
677
678 void
679 shmexit(struct vmspace *vm)
680 {
681         struct shmmap_state *base, *shm;
682         int i;
683
684         if ((base = (struct shmmap_state *)vm->vm_shm) != NULL) {
685                 vm->vm_shm = NULL;
686                 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) {
687                         if (shm->shmid != -1)
688                                 shm_delete_mapping(vm, shm);
689                 }
690                 kfree(base, M_SHM);
691         }
692 }
693
694 static void
695 shmrealloc(void)
696 {
697         int i;
698         struct shmid_ds *newsegs;
699
700         if (shmalloced >= shminfo.shmmni)
701                 return;
702
703         newsegs = kmalloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
704         for (i = 0; i < shmalloced; i++)
705                 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
706         for (; i < shminfo.shmmni; i++) {
707                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
708                 shmsegs[i].shm_perm.seq = 0;
709         }
710         kfree(shmsegs, M_SHM);
711         shmsegs = newsegs;
712         shmalloced = shminfo.shmmni;
713 }
714
715 static void
716 shminit(void *dummy)
717 {
718         int i;
719
720         shminfo.shmmax = shminfo.shmall * PAGE_SIZE;
721         shmalloced = shminfo.shmmni;
722         shmsegs = kmalloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
723         for (i = 0; i < shmalloced; i++) {
724                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
725                 shmsegs[i].shm_perm.seq = 0;
726         }
727         shm_last_free = 0;
728         shm_nused = 0;
729         shm_committed = 0;
730 }
731 SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL);