sys/kern/sysv_shm.c

   1 /* $FreeBSD$ */
   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/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 oshmctl __P((struct proc *p, struct oshmctl_args *uap));
  64
  65 static int shmget_allocate_segment __P((struct proc *p, struct shmget_args *uap, int mode));
  66 static int shmget_existing __P((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 *)shmat, (sy_call_t *)oshmctl,
  71         (sy_call_t *)shmdt, (sy_call_t *)shmget,
  72         (sy_call_t *)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 __P((struct shmid_ds *));
  94 static int shm_find_segment_by_key __P((key_t));
  95 static struct shmid_ds *shm_find_segment_by_shmid __P((int));
  96 static int shm_delete_mapping __P((struct proc *, struct shmmap_state *));
  97 static void shmrealloc __P((void));
  98 static void shminit __P((void *));
  99
 100 /*
 101  * Tuneable values
 102  */
 103 #ifndef SHMMAXPGS
 104 #define SHMMAXPGS       1024    /* XXX increase this, it's not in kva! */
 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  96
 114 #endif
 115 #ifndef SHMSEG
 116 #define SHMSEG  64
 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 SYSCTL_DECL(_kern_ipc);
 133 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, "");
 134 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, "");
 135 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0, "");
 136 SYSCTL_INT(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RW, &shminfo.shmseg, 0, "");
 137 SYSCTL_INT(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, "");
 138 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, &shm_use_phys, 0, "");
 139
 140 static int
 141 shm_find_segment_by_key(key)
 142         key_t key;
 143 {
 144         int i;
 145
 146         for (i = 0; i < shmalloced; i++)
 147                 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) &&
 148                     shmsegs[i].shm_perm.key == key)
 149                         return i;
 150         return -1;
 151 }
 152
 153 static struct shmid_ds *
 154 shm_find_segment_by_shmid(shmid)
 155         int shmid;
 156 {
 157         int segnum;
 158         struct shmid_ds *shmseg;
 159
 160         segnum = IPCID_TO_IX(shmid);
 161         if (segnum < 0 || segnum >= shmalloced)
 162                 return NULL;
 163         shmseg = &shmsegs[segnum];
 164         if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED))
 165             != SHMSEG_ALLOCATED ||
 166             shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid))
 167                 return NULL;
 168         return shmseg;
 169 }
 170
 171 static void
 172 shm_deallocate_segment(shmseg)
 173         struct shmid_ds *shmseg;
 174 {
 175         struct shm_handle *shm_handle;
 176         size_t size;
 177
 178         shm_handle = shmseg->shm_internal;
 179         vm_object_deallocate(shm_handle->shm_object);
 180         free((caddr_t)shm_handle, M_SHM);
 181         shmseg->shm_internal = NULL;
 182         size = round_page(shmseg->shm_segsz);
 183         shm_committed -= btoc(size);
 184         shm_nused--;
 185         shmseg->shm_perm.mode = SHMSEG_FREE;
 186 }
 187
 188 static int
 189 shm_delete_mapping(p, shmmap_s)
 190         struct proc *p;
 191         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(&p->p_vmspace->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 #ifndef _SYS_SYSPROTO_H_
 214 struct shmdt_args {
 215         void *shmaddr;
 216 };
 217 #endif
 218
 219 int
 220 shmdt(p, uap)
 221         struct proc *p;
 222         struct shmdt_args *uap;
 223 {
 224         struct shmmap_state *shmmap_s;
 225         int i;
 226
 227         if (!jail_sysvipc_allowed && p->p_prison != NULL)
 228                 return (ENOSYS);
 229
 230         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
 231         if (shmmap_s == NULL)
 232             return EINVAL;
 233         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
 234                 if (shmmap_s->shmid != -1 &&
 235                     shmmap_s->va == (vm_offset_t)uap->shmaddr)
 236                         break;
 237         if (i == shminfo.shmseg)
 238                 return EINVAL;
 239         return shm_delete_mapping(p, shmmap_s);
 240 }
 241
 242 #ifndef _SYS_SYSPROTO_H_
 243 struct shmat_args {
 244         int shmid;
 245         void *shmaddr;
 246         int shmflg;
 247 };
 248 #endif
 249
 250 int
 251 shmat(p, uap)
 252         struct proc *p;
 253         struct shmat_args *uap;
 254 {
 255         int error, i, flags;
 256         struct shmid_ds *shmseg;
 257         struct shmmap_state *shmmap_s = NULL;
 258         struct shm_handle *shm_handle;
 259         vm_offset_t attach_va;
 260         vm_prot_t prot;
 261         vm_size_t size;
 262         int rv;
 263
 264         if (!jail_sysvipc_allowed && p->p_prison != NULL)
 265                 return (ENOSYS);
 266
 267         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
 268         if (shmmap_s == NULL) {
 269                 size = shminfo.shmseg * sizeof(struct shmmap_state);
 270                 shmmap_s = malloc(size, M_SHM, M_WAITOK);
 271                 for (i = 0; i < shminfo.shmseg; i++)
 272                         shmmap_s[i].shmid = -1;
 273                 p->p_vmspace->vm_shm = (caddr_t)shmmap_s;
 274         }
 275         shmseg = shm_find_segment_by_shmid(uap->shmid);
 276         if (shmseg == NULL)
 277                 return EINVAL;
 278         error = ipcperm(p, &shmseg->shm_perm,
 279             (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
 280         if (error)
 281                 return error;
 282         for (i = 0; i < shminfo.shmseg; i++) {
 283                 if (shmmap_s->shmid == -1)
 284                         break;
 285                 shmmap_s++;
 286         }
 287         if (i >= shminfo.shmseg)
 288                 return EMFILE;
 289         size = round_page(shmseg->shm_segsz);
 290 #ifdef VM_PROT_READ_IS_EXEC
 291         prot = VM_PROT_READ | VM_PROT_EXECUTE;
 292 #else
 293         prot = VM_PROT_READ;
 294 #endif
 295         if ((uap->shmflg & SHM_RDONLY) == 0)
 296                 prot |= VM_PROT_WRITE;
 297         flags = MAP_ANON | MAP_SHARED;
 298         if (uap->shmaddr) {
 299                 flags |= MAP_FIXED;
 300                 if (uap->shmflg & SHM_RND)
 301                         attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1);
 302                 else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0)
 303                         attach_va = (vm_offset_t)uap->shmaddr;
 304                 else
 305                         return EINVAL;
 306         } else {
 307                 /* This is just a hint to vm_map_find() about where to put it. */
 308                 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr + MAXTSIZ + MAXDSIZ);
 309         }
 310
 311         shm_handle = shmseg->shm_internal;
 312         vm_object_reference(shm_handle->shm_object);
 313         rv = vm_map_find(&p->p_vmspace->vm_map, shm_handle->shm_object,
 314                 0, &attach_va, size, (flags & MAP_FIXED)?0:1, prot, prot, 0);
 315         if (rv != KERN_SUCCESS) {
 316                 return ENOMEM;
 317         }
 318         vm_map_inherit(&p->p_vmspace->vm_map,
 319                 attach_va, attach_va + size, VM_INHERIT_SHARE);
 320
 321         shmmap_s->va = attach_va;
 322         shmmap_s->shmid = uap->shmid;
 323         shmseg->shm_lpid = p->p_pid;
 324         shmseg->shm_atime = time_second;
 325         shmseg->shm_nattch++;
 326         p->p_retval[0] = attach_va;
 327         return 0;
 328 }
 329
 330 struct oshmid_ds {
 331         struct  ipc_perm shm_perm;      /* operation perms */
 332         int     shm_segsz;              /* size of segment (bytes) */
 333         ushort  shm_cpid;               /* pid, creator */
 334         ushort  shm_lpid;               /* pid, last operation */
 335         short   shm_nattch;             /* no. of current attaches */
 336         time_t  shm_atime;              /* last attach time */
 337         time_t  shm_dtime;              /* last detach time */
 338         time_t  shm_ctime;              /* last change time */
 339         void    *shm_handle;            /* internal handle for shm segment */
 340 };
 341
 342 struct oshmctl_args {
 343         int shmid;
 344         int cmd;
 345         struct oshmid_ds *ubuf;
 346 };
 347
 348 static int
 349 oshmctl(p, uap)
 350         struct proc *p;
 351         struct oshmctl_args *uap;
 352 {
 353 #ifdef COMPAT_43
 354         int error;
 355         struct shmid_ds *shmseg;
 356         struct oshmid_ds outbuf;
 357
 358         if (!jail_sysvipc_allowed && p->p_prison != NULL)
 359                 return (ENOSYS);
 360
 361         shmseg = shm_find_segment_by_shmid(uap->shmid);
 362         if (shmseg == NULL)
 363                 return EINVAL;
 364         switch (uap->cmd) {
 365         case IPC_STAT:
 366                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
 367                 if (error)
 368                         return error;
 369                 outbuf.shm_perm = shmseg->shm_perm;
 370                 outbuf.shm_segsz = shmseg->shm_segsz;
 371                 outbuf.shm_cpid = shmseg->shm_cpid;
 372                 outbuf.shm_lpid = shmseg->shm_lpid;
 373                 outbuf.shm_nattch = shmseg->shm_nattch;
 374                 outbuf.shm_atime = shmseg->shm_atime;
 375                 outbuf.shm_dtime = shmseg->shm_dtime;
 376                 outbuf.shm_ctime = shmseg->shm_ctime;
 377                 outbuf.shm_handle = shmseg->shm_internal;
 378                 error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf));
 379                 if (error)
 380                         return error;
 381                 break;
 382         default:
 383                 /* XXX casting to (sy_call_t *) is bogus, as usual. */
 384                 return ((sy_call_t *)shmctl)(p, uap);
 385         }
 386         return 0;
 387 #else
 388         return EINVAL;
 389 #endif
 390 }
 391
 392 #ifndef _SYS_SYSPROTO_H_
 393 struct shmctl_args {
 394         int shmid;
 395         int cmd;
 396         struct shmid_ds *buf;
 397 };
 398 #endif
 399
 400 int
 401 shmctl(p, uap)
 402         struct proc *p;
 403         struct shmctl_args *uap;
 404 {
 405         int error;
 406         struct shmid_ds inbuf;
 407         struct shmid_ds *shmseg;
 408
 409         if (!jail_sysvipc_allowed && p->p_prison != NULL)
 410                 return (ENOSYS);
 411
 412         shmseg = shm_find_segment_by_shmid(uap->shmid);
 413         if (shmseg == NULL)
 414                 return EINVAL;
 415         switch (uap->cmd) {
 416         case IPC_STAT:
 417                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
 418                 if (error)
 419                         return error;
 420                 error = copyout((caddr_t)shmseg, uap->buf, sizeof(inbuf));
 421                 if (error)
 422                         return error;
 423                 break;
 424         case IPC_SET:
 425                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
 426                 if (error)
 427                         return error;
 428                 error = copyin(uap->buf, (caddr_t)&inbuf, sizeof(inbuf));
 429                 if (error)
 430                         return error;
 431                 shmseg->shm_perm.uid = inbuf.shm_perm.uid;
 432                 shmseg->shm_perm.gid = inbuf.shm_perm.gid;
 433                 shmseg->shm_perm.mode =
 434                     (shmseg->shm_perm.mode & ~ACCESSPERMS) |
 435                     (inbuf.shm_perm.mode & ACCESSPERMS);
 436                 shmseg->shm_ctime = time_second;
 437                 break;
 438         case IPC_RMID:
 439                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
 440                 if (error)
 441                         return error;
 442                 shmseg->shm_perm.key = IPC_PRIVATE;
 443                 shmseg->shm_perm.mode |= SHMSEG_REMOVED;
 444                 if (shmseg->shm_nattch <= 0) {
 445                         shm_deallocate_segment(shmseg);
 446                         shm_last_free = IPCID_TO_IX(uap->shmid);
 447                 }
 448                 break;
 449 #if 0
 450         case SHM_LOCK:
 451         case SHM_UNLOCK:
 452 #endif
 453         default:
 454                 return EINVAL;
 455         }
 456         return 0;
 457 }
 458
 459 #ifndef _SYS_SYSPROTO_H_
 460 struct shmget_args {
 461         key_t key;
 462         size_t size;
 463         int shmflg;
 464 };
 465 #endif
 466
 467 static int
 468 shmget_existing(p, uap, mode, segnum)
 469         struct proc *p;
 470         struct shmget_args *uap;
 471         int mode;
 472         int segnum;
 473 {
 474         struct shmid_ds *shmseg;
 475         int error;
 476
 477         shmseg = &shmsegs[segnum];
 478         if (shmseg->shm_perm.mode & SHMSEG_REMOVED) {
 479                 /*
 480                  * This segment is in the process of being allocated.  Wait
 481                  * until it's done, and look the key up again (in case the
 482                  * allocation failed or it was freed).
 483                  */
 484                 shmseg->shm_perm.mode |= SHMSEG_WANTED;
 485                 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0);
 486                 if (error)
 487                         return error;
 488                 return EAGAIN;
 489         }
 490         if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
 491                 return EEXIST;
 492         error = ipcperm(p, &shmseg->shm_perm, mode);
 493         if (error)
 494                 return error;
 495         if (uap->size && uap->size > shmseg->shm_segsz)
 496                 return EINVAL;
 497         p->p_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
 498         return 0;
 499 }
 500
 501 static int
 502 shmget_allocate_segment(p, uap, mode)
 503         struct proc *p;
 504         struct shmget_args *uap;
 505         int mode;
 506 {
 507         int i, segnum, shmid, size;
 508         struct ucred *cred = p->p_ucred;
 509         struct shmid_ds *shmseg;
 510         struct shm_handle *shm_handle;
 511
 512         if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
 513                 return EINVAL;
 514         if (shm_nused >= shminfo.shmmni) /* any shmids left? */
 515                 return ENOSPC;
 516         size = round_page(uap->size);
 517         if (shm_committed + btoc(size) > shminfo.shmall)
 518                 return ENOMEM;
 519         if (shm_last_free < 0) {
 520                 shmrealloc();   /* maybe expand the shmsegs[] array */
 521                 for (i = 0; i < shmalloced; i++)
 522                         if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
 523                                 break;
 524                 if (i == shmalloced)
 525                         return ENOSPC;
 526                 segnum = i;
 527         } else  {
 528                 segnum = shm_last_free;
 529                 shm_last_free = -1;
 530         }
 531         shmseg = &shmsegs[segnum];
 532         /*
 533          * In case we sleep in malloc(), mark the segment present but deleted
 534          * so that noone else tries to create the same key.
 535          */
 536         shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
 537         shmseg->shm_perm.key = uap->key;
 538         shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff;
 539         shm_handle = (struct shm_handle *)
 540             malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK);
 541         shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
 542
 543         /*
 544          * We make sure that we have allocated a pager before we need
 545          * to.
 546          */
 547         if (shm_use_phys) {
 548                 shm_handle->shm_object =
 549                     vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0);
 550         } else {
 551                 shm_handle->shm_object =
 552                     vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0);
 553         }
 554         vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING);
 555         vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT);
 556
 557         shmseg->shm_internal = shm_handle;
 558         shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid;
 559         shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid;
 560         shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
 561             (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
 562         shmseg->shm_segsz = uap->size;
 563         shmseg->shm_cpid = p->p_pid;
 564         shmseg->shm_lpid = shmseg->shm_nattch = 0;
 565         shmseg->shm_atime = shmseg->shm_dtime = 0;
 566         shmseg->shm_ctime = time_second;
 567         shm_committed += btoc(size);
 568         shm_nused++;
 569         if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
 570                 /*
 571                  * Somebody else wanted this key while we were asleep.  Wake
 572                  * them up now.
 573                  */
 574                 shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
 575                 wakeup((caddr_t)shmseg);
 576         }
 577         p->p_retval[0] = shmid;
 578         return 0;
 579 }
 580
 581 int
 582 shmget(p, uap)
 583         struct proc *p;
 584         struct shmget_args *uap;
 585 {
 586         int segnum, mode, error;
 587
 588         if (!jail_sysvipc_allowed && p->p_prison != NULL)
 589                 return (ENOSYS);
 590
 591         mode = uap->shmflg & ACCESSPERMS;
 592         if (uap->key != IPC_PRIVATE) {
 593         again:
 594                 segnum = shm_find_segment_by_key(uap->key);
 595                 if (segnum >= 0) {
 596                         error = shmget_existing(p, uap, mode, segnum);
 597                         if (error == EAGAIN)
 598                                 goto again;
 599                         return error;
 600                 }
 601                 if ((uap->shmflg & IPC_CREAT) == 0)
 602                         return ENOENT;
 603         }
 604         return shmget_allocate_segment(p, uap, mode);
 605 }
 606
 607 int
 608 shmsys(p, uap)
 609         struct proc *p;
 610         /* XXX actually varargs. */
 611         struct shmsys_args /* {
 612                 u_int   which;
 613                 int     a2;
 614                 int     a3;
 615                 int     a4;
 616         } */ *uap;
 617 {
 618
 619         if (!jail_sysvipc_allowed && p->p_prison != NULL)
 620                 return (ENOSYS);
 621
 622         if (uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
 623                 return EINVAL;
 624         return ((*shmcalls[uap->which])(p, &uap->a2));
 625 }
 626
 627 void
 628 shmfork(p1, p2)
 629         struct proc *p1, *p2;
 630 {
 631         struct shmmap_state *shmmap_s;
 632         size_t size;
 633         int i;
 634
 635         size = shminfo.shmseg * sizeof(struct shmmap_state);
 636         shmmap_s = malloc(size, M_SHM, M_WAITOK);
 637         bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size);
 638         p2->p_vmspace->vm_shm = (caddr_t)shmmap_s;
 639         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
 640                 if (shmmap_s->shmid != -1)
 641                         shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++;
 642 }
 643
 644 void
 645 shmexit(p)
 646         struct proc *p;
 647 {
 648         struct shmmap_state *shmmap_s;
 649         int i;
 650
 651         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
 652         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
 653                 if (shmmap_s->shmid != -1)
 654                         shm_delete_mapping(p, shmmap_s);
 655         free((caddr_t)p->p_vmspace->vm_shm, M_SHM);
 656         p->p_vmspace->vm_shm = NULL;
 657 }
 658
 659 static void
 660 shmrealloc(void)
 661 {
 662         int i;
 663         struct shmid_ds *newsegs;
 664
 665         if (shmalloced >= shminfo.shmmni)
 666                 return;
 667
 668         newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
 669         if (newsegs == NULL)
 670                 return;
 671         for (i = 0; i < shmalloced; i++)
 672                 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
 673         for (; i < shminfo.shmmni; i++) {
 674                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
 675                 shmsegs[i].shm_perm.seq = 0;
 676         }
 677         free(shmsegs, M_SHM);
 678         shmsegs = newsegs;
 679         shmalloced = shminfo.shmmni;
 680 }
 681
 682 static void
 683 shminit(dummy)
 684         void *dummy;
 685 {
 686         int i;
 687
 688         shmalloced = shminfo.shmmni;
 689         shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
 690         if (shmsegs == NULL)
 691                 panic("cannot allocate initial memory for sysvshm");
 692         for (i = 0; i < shmalloced; i++) {
 693                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
 694                 shmsegs[i].shm_perm.seq = 0;
 695         }
 696         shm_last_free = 0;
 697         shm_nused = 0;
 698         shm_committed = 0;
 699 }
 700 SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL);