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 <vm/vm.h>
  51 #include <vm/vm_param.h>
  52 #include <sys/lock.h>
  53 #include <vm/pmap.h>
  54 #include <vm/vm_object.h>
  55 #include <vm/vm_map.h>
  56 #include <vm/vm_page.h>
  57 #include <vm/vm_pager.h>
  58
  59 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments");
  60
  61 struct oshmctl_args;
  62 static int oshmctl __P((struct proc *p, struct oshmctl_args *uap));
  63
  64 static int shmget_allocate_segment __P((struct proc *p, struct shmget_args *uap, int mode));
  65 static int shmget_existing __P((struct proc *p, struct shmget_args *uap, int mode, int segnum));
  66
  67 /* XXX casting to (sy_call_t *) is bogus, as usual. */
  68 static sy_call_t *shmcalls[] = {
  69         (sy_call_t *)shmat, (sy_call_t *)oshmctl,
  70         (sy_call_t *)shmdt, (sy_call_t *)shmget,
  71         (sy_call_t *)shmctl
  72 };
  73
  74 #define SHMSEG_FREE             0x0200
  75 #define SHMSEG_REMOVED          0x0400
  76 #define SHMSEG_ALLOCATED        0x0800
  77 #define SHMSEG_WANTED           0x1000
  78
  79 static int shm_last_free, shm_nused, shm_committed, shmalloced;
  80 static struct shmid_ds  *shmsegs;
  81
  82 struct shm_handle {
  83         /* vm_offset_t kva; */
  84         vm_object_t shm_object;
  85 };
  86
  87 struct shmmap_state {
  88         vm_offset_t va;
  89         int shmid;
  90 };
  91
  92 static void shm_deallocate_segment __P((struct shmid_ds *));
  93 static int shm_find_segment_by_key __P((key_t));
  94 static struct shmid_ds *shm_find_segment_by_shmid __P((int));
  95 static int shm_delete_mapping __P((struct proc *, struct shmmap_state *));
  96 static void shmrealloc __P((void));
  97 static void shminit __P((void *));
  98
  99 /*
 100  * Tuneable values
 101  */
 102 #ifndef SHMMAXPGS
 103 #define SHMMAXPGS       8192    /* note: sysv shared memory is swap backed */
 104 #endif
 105 #ifndef SHMMAX
 106 #define SHMMAX  (SHMMAXPGS*PAGE_SIZE)
 107 #endif
 108 #ifndef SHMMIN
 109 #define SHMMIN  1
 110 #endif
 111 #ifndef SHMMNI
 112 #define SHMMNI  192
 113 #endif
 114 #ifndef SHMSEG
 115 #define SHMSEG  128
 116 #endif
 117 #ifndef SHMALL
 118 #define SHMALL  (SHMMAXPGS)
 119 #endif
 120
 121 struct  shminfo shminfo = {
 122         SHMMAX,
 123         SHMMIN,
 124         SHMMNI,
 125         SHMSEG,
 126         SHMALL
 127 };
 128
 129 static int shm_use_phys;
 130
 131 TUNABLE_INT("kern.ipc.shmmin", &shminfo.shmmin);
 132 TUNABLE_INT("kern.ipc.shmmni", &shminfo.shmmni);
 133 TUNABLE_INT("kern.ipc.shmseg", &shminfo.shmseg);
 134 TUNABLE_INT("kern.ipc.shmmaxpgs", &shminfo.shmall);
 135 TUNABLE_INT("kern.ipc.shm_use_phys", &shm_use_phys);
 136
 137 SYSCTL_DECL(_kern_ipc);
 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)
 147         key_t key;
 148 {
 149         int i;
 150
 151         for (i = 0; i < shmalloced; i++)
 152                 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) &&
 153                     shmsegs[i].shm_perm.key == key)
 154                         return i;
 155         return -1;
 156 }
 157
 158 static struct shmid_ds *
 159 shm_find_segment_by_shmid(shmid)
 160         int shmid;
 161 {
 162         int segnum;
 163         struct shmid_ds *shmseg;
 164
 165         segnum = IPCID_TO_IX(shmid);
 166         if (segnum < 0 || segnum >= shmalloced)
 167                 return NULL;
 168         shmseg = &shmsegs[segnum];
 169         if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED))
 170             != SHMSEG_ALLOCATED ||
 171             shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid))
 172                 return NULL;
 173         return shmseg;
 174 }
 175
 176 static void
 177 shm_deallocate_segment(shmseg)
 178         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         free((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(p, shmmap_s)
 195         struct proc *p;
 196         struct shmmap_state *shmmap_s;
 197 {
 198         struct shmid_ds *shmseg;
 199         int segnum, result;
 200         size_t size;
 201
 202         segnum = IPCID_TO_IX(shmmap_s->shmid);
 203         shmseg = &shmsegs[segnum];
 204         size = round_page(shmseg->shm_segsz);
 205         result = vm_map_remove(&p->p_vmspace->vm_map, shmmap_s->va, shmmap_s->va + size);
 206         if (result != KERN_SUCCESS)
 207                 return EINVAL;
 208         shmmap_s->shmid = -1;
 209         shmseg->shm_dtime = time_second;
 210         if ((--shmseg->shm_nattch <= 0) &&
 211             (shmseg->shm_perm.mode & SHMSEG_REMOVED)) {
 212                 shm_deallocate_segment(shmseg);
 213                 shm_last_free = segnum;
 214         }
 215         return 0;
 216 }
 217
 218 #ifndef _SYS_SYSPROTO_H_
 219 struct shmdt_args {
 220         void *shmaddr;
 221 };
 222 #endif
 223
 224 int
 225 shmdt(p, uap)
 226         struct proc *p;
 227         struct shmdt_args *uap;
 228 {
 229         struct shmmap_state *shmmap_s;
 230         int i;
 231
 232         if (!jail_sysvipc_allowed && p->p_prison != NULL)
 233                 return (ENOSYS);
 234
 235         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
 236         if (shmmap_s == NULL)
 237             return EINVAL;
 238         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
 239                 if (shmmap_s->shmid != -1 &&
 240                     shmmap_s->va == (vm_offset_t)uap->shmaddr)
 241                         break;
 242         if (i == shminfo.shmseg)
 243                 return EINVAL;
 244         return shm_delete_mapping(p, shmmap_s);
 245 }
 246
 247 #ifndef _SYS_SYSPROTO_H_
 248 struct shmat_args {
 249         int shmid;
 250         void *shmaddr;
 251         int shmflg;
 252 };
 253 #endif
 254
 255 int
 256 shmat(p, uap)
 257         struct proc *p;
 258         struct shmat_args *uap;
 259 {
 260         int error, i, flags;
 261         struct shmid_ds *shmseg;
 262         struct shmmap_state *shmmap_s = NULL;
 263         struct shm_handle *shm_handle;
 264         vm_offset_t attach_va;
 265         vm_prot_t prot;
 266         vm_size_t size;
 267         int rv;
 268
 269         if (!jail_sysvipc_allowed && p->p_prison != NULL)
 270                 return (ENOSYS);
 271
 272         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
 273         if (shmmap_s == NULL) {
 274                 size = shminfo.shmseg * sizeof(struct shmmap_state);
 275                 shmmap_s = malloc(size, M_SHM, M_WAITOK);
 276                 for (i = 0; i < shminfo.shmseg; i++)
 277                         shmmap_s[i].shmid = -1;
 278                 p->p_vmspace->vm_shm = (caddr_t)shmmap_s;
 279         }
 280         shmseg = shm_find_segment_by_shmid(uap->shmid);
 281         if (shmseg == NULL)
 282                 return EINVAL;
 283         error = ipcperm(p, &shmseg->shm_perm,
 284             (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
 285         if (error)
 286                 return error;
 287         for (i = 0; i < shminfo.shmseg; i++) {
 288                 if (shmmap_s->shmid == -1)
 289                         break;
 290                 shmmap_s++;
 291         }
 292         if (i >= shminfo.shmseg)
 293                 return EMFILE;
 294         size = round_page(shmseg->shm_segsz);
 295 #ifdef VM_PROT_READ_IS_EXEC
 296         prot = VM_PROT_READ | VM_PROT_EXECUTE;
 297 #else
 298         prot = VM_PROT_READ;
 299 #endif
 300         if ((uap->shmflg & SHM_RDONLY) == 0)
 301                 prot |= VM_PROT_WRITE;
 302         flags = MAP_ANON | MAP_SHARED;
 303         if (uap->shmaddr) {
 304                 flags |= MAP_FIXED;
 305                 if (uap->shmflg & SHM_RND)
 306                         attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1);
 307                 else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0)
 308                         attach_va = (vm_offset_t)uap->shmaddr;
 309                 else
 310                         return EINVAL;
 311         } else {
 312                 /* This is just a hint to vm_map_find() about where to put it. */
 313                 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr + maxtsiz + maxdsiz);
 314         }
 315
 316         shm_handle = shmseg->shm_internal;
 317         vm_object_reference(shm_handle->shm_object);
 318         rv = vm_map_find(&p->p_vmspace->vm_map, shm_handle->shm_object,
 319                 0, &attach_va, size, (flags & MAP_FIXED)?0:1, prot, prot, 0);
 320         if (rv != KERN_SUCCESS) {
 321                 return ENOMEM;
 322         }
 323         vm_map_inherit(&p->p_vmspace->vm_map,
 324                 attach_va, attach_va + size, VM_INHERIT_SHARE);
 325
 326         shmmap_s->va = attach_va;
 327         shmmap_s->shmid = uap->shmid;
 328         shmseg->shm_lpid = p->p_pid;
 329         shmseg->shm_atime = time_second;
 330         shmseg->shm_nattch++;
 331         p->p_retval[0] = attach_va;
 332         return 0;
 333 }
 334
 335 struct oshmid_ds {
 336         struct  ipc_perm shm_perm;      /* operation perms */
 337         int     shm_segsz;              /* size of segment (bytes) */
 338         ushort  shm_cpid;               /* pid, creator */
 339         ushort  shm_lpid;               /* pid, last operation */
 340         short   shm_nattch;             /* no. of current attaches */
 341         time_t  shm_atime;              /* last attach time */
 342         time_t  shm_dtime;              /* last detach time */
 343         time_t  shm_ctime;              /* last change time */
 344         void    *shm_handle;            /* internal handle for shm segment */
 345 };
 346
 347 struct oshmctl_args {
 348         int shmid;
 349         int cmd;
 350         struct oshmid_ds *ubuf;
 351 };
 352
 353 static int
 354 oshmctl(p, uap)
 355         struct proc *p;
 356         struct oshmctl_args *uap;
 357 {
 358 #ifdef COMPAT_43
 359         int error;
 360         struct shmid_ds *shmseg;
 361         struct oshmid_ds outbuf;
 362
 363         if (!jail_sysvipc_allowed && p->p_prison != NULL)
 364                 return (ENOSYS);
 365
 366         shmseg = shm_find_segment_by_shmid(uap->shmid);
 367         if (shmseg == NULL)
 368                 return EINVAL;
 369         switch (uap->cmd) {
 370         case IPC_STAT:
 371                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
 372                 if (error)
 373                         return error;
 374                 outbuf.shm_perm = shmseg->shm_perm;
 375                 outbuf.shm_segsz = shmseg->shm_segsz;
 376                 outbuf.shm_cpid = shmseg->shm_cpid;
 377                 outbuf.shm_lpid = shmseg->shm_lpid;
 378                 outbuf.shm_nattch = shmseg->shm_nattch;
 379                 outbuf.shm_atime = shmseg->shm_atime;
 380                 outbuf.shm_dtime = shmseg->shm_dtime;
 381                 outbuf.shm_ctime = shmseg->shm_ctime;
 382                 outbuf.shm_handle = shmseg->shm_internal;
 383                 error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf));
 384                 if (error)
 385                         return error;
 386                 break;
 387         default:
 388                 /* XXX casting to (sy_call_t *) is bogus, as usual. */
 389                 return ((sy_call_t *)shmctl)(p, uap);
 390         }
 391         return 0;
 392 #else
 393         return EINVAL;
 394 #endif
 395 }
 396
 397 #ifndef _SYS_SYSPROTO_H_
 398 struct shmctl_args {
 399         int shmid;
 400         int cmd;
 401         struct shmid_ds *buf;
 402 };
 403 #endif
 404
 405 int
 406 shmctl(p, uap)
 407         struct proc *p;
 408         struct shmctl_args *uap;
 409 {
 410         int error;
 411         struct shmid_ds inbuf;
 412         struct shmid_ds *shmseg;
 413
 414         if (!jail_sysvipc_allowed && p->p_prison != NULL)
 415                 return (ENOSYS);
 416
 417         shmseg = shm_find_segment_by_shmid(uap->shmid);
 418         if (shmseg == NULL)
 419                 return EINVAL;
 420         switch (uap->cmd) {
 421         case IPC_STAT:
 422                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
 423                 if (error)
 424                         return error;
 425                 error = copyout((caddr_t)shmseg, uap->buf, sizeof(inbuf));
 426                 if (error)
 427                         return error;
 428                 break;
 429         case IPC_SET:
 430                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
 431                 if (error)
 432                         return error;
 433                 error = copyin(uap->buf, (caddr_t)&inbuf, sizeof(inbuf));
 434                 if (error)
 435                         return error;
 436                 shmseg->shm_perm.uid = inbuf.shm_perm.uid;
 437                 shmseg->shm_perm.gid = inbuf.shm_perm.gid;
 438                 shmseg->shm_perm.mode =
 439                     (shmseg->shm_perm.mode & ~ACCESSPERMS) |
 440                     (inbuf.shm_perm.mode & ACCESSPERMS);
 441                 shmseg->shm_ctime = time_second;
 442                 break;
 443         case IPC_RMID:
 444                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
 445                 if (error)
 446                         return error;
 447                 shmseg->shm_perm.key = IPC_PRIVATE;
 448                 shmseg->shm_perm.mode |= SHMSEG_REMOVED;
 449                 if (shmseg->shm_nattch <= 0) {
 450                         shm_deallocate_segment(shmseg);
 451                         shm_last_free = IPCID_TO_IX(uap->shmid);
 452                 }
 453                 break;
 454 #if 0
 455         case SHM_LOCK:
 456         case SHM_UNLOCK:
 457 #endif
 458         default:
 459                 return EINVAL;
 460         }
 461         return 0;
 462 }
 463
 464 #ifndef _SYS_SYSPROTO_H_
 465 struct shmget_args {
 466         key_t key;
 467         size_t size;
 468         int shmflg;
 469 };
 470 #endif
 471
 472 static int
 473 shmget_existing(p, uap, mode, segnum)
 474         struct proc *p;
 475         struct shmget_args *uap;
 476         int mode;
 477         int segnum;
 478 {
 479         struct shmid_ds *shmseg;
 480         int error;
 481
 482         shmseg = &shmsegs[segnum];
 483         if (shmseg->shm_perm.mode & SHMSEG_REMOVED) {
 484                 /*
 485                  * This segment is in the process of being allocated.  Wait
 486                  * until it's done, and look the key up again (in case the
 487                  * allocation failed or it was freed).
 488                  */
 489                 shmseg->shm_perm.mode |= SHMSEG_WANTED;
 490                 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0);
 491                 if (error)
 492                         return error;
 493                 return EAGAIN;
 494         }
 495         if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
 496                 return EEXIST;
 497         error = ipcperm(p, &shmseg->shm_perm, mode);
 498         if (error)
 499                 return error;
 500         if (uap->size && uap->size > shmseg->shm_segsz)
 501                 return EINVAL;
 502         p->p_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
 503         return 0;
 504 }
 505
 506 static int
 507 shmget_allocate_segment(p, uap, mode)
 508         struct proc *p;
 509         struct shmget_args *uap;
 510         int mode;
 511 {
 512         int i, segnum, shmid, size;
 513         struct ucred *cred = p->p_ucred;
 514         struct shmid_ds *shmseg;
 515         struct shm_handle *shm_handle;
 516
 517         if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
 518                 return EINVAL;
 519         if (shm_nused >= shminfo.shmmni) /* any shmids left? */
 520                 return ENOSPC;
 521         size = round_page(uap->size);
 522         if (shm_committed + btoc(size) > shminfo.shmall)
 523                 return ENOMEM;
 524         if (shm_last_free < 0) {
 525                 shmrealloc();   /* maybe expand the shmsegs[] array */
 526                 for (i = 0; i < shmalloced; i++)
 527                         if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
 528                                 break;
 529                 if (i == shmalloced)
 530                         return ENOSPC;
 531                 segnum = i;
 532         } else  {
 533                 segnum = shm_last_free;
 534                 shm_last_free = -1;
 535         }
 536         shmseg = &shmsegs[segnum];
 537         /*
 538          * In case we sleep in malloc(), mark the segment present but deleted
 539          * so that noone else tries to create the same key.
 540          */
 541         shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
 542         shmseg->shm_perm.key = uap->key;
 543         shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff;
 544         shm_handle = (struct shm_handle *)
 545             malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK);
 546         shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
 547
 548         /*
 549          * We make sure that we have allocated a pager before we need
 550          * to.
 551          */
 552         if (shm_use_phys) {
 553                 shm_handle->shm_object =
 554                     vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0);
 555         } else {
 556                 shm_handle->shm_object =
 557                     vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0);
 558         }
 559         vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING);
 560         vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT);
 561
 562         shmseg->shm_internal = shm_handle;
 563         shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid;
 564         shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid;
 565         shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
 566             (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
 567         shmseg->shm_segsz = uap->size;
 568         shmseg->shm_cpid = p->p_pid;
 569         shmseg->shm_lpid = shmseg->shm_nattch = 0;
 570         shmseg->shm_atime = shmseg->shm_dtime = 0;
 571         shmseg->shm_ctime = time_second;
 572         shm_committed += btoc(size);
 573         shm_nused++;
 574         if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
 575                 /*
 576                  * Somebody else wanted this key while we were asleep.  Wake
 577                  * them up now.
 578                  */
 579                 shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
 580                 wakeup((caddr_t)shmseg);
 581         }
 582         p->p_retval[0] = shmid;
 583         return 0;
 584 }
 585
 586 int
 587 shmget(p, uap)
 588         struct proc *p;
 589         struct shmget_args *uap;
 590 {
 591         int segnum, mode, error;
 592
 593         if (!jail_sysvipc_allowed && p->p_prison != NULL)
 594                 return (ENOSYS);
 595
 596         mode = uap->shmflg & ACCESSPERMS;
 597         if (uap->key != IPC_PRIVATE) {
 598         again:
 599                 segnum = shm_find_segment_by_key(uap->key);
 600                 if (segnum >= 0) {
 601                         error = shmget_existing(p, uap, mode, segnum);
 602                         if (error == EAGAIN)
 603                                 goto again;
 604                         return error;
 605                 }
 606                 if ((uap->shmflg & IPC_CREAT) == 0)
 607                         return ENOENT;
 608         }
 609         return shmget_allocate_segment(p, uap, mode);
 610 }
 611
 612 int
 613 shmsys(p, uap)
 614         struct proc *p;
 615         /* XXX actually varargs. */
 616         struct shmsys_args /* {
 617                 u_int   which;
 618                 int     a2;
 619                 int     a3;
 620                 int     a4;
 621         } */ *uap;
 622 {
 623
 624         if (!jail_sysvipc_allowed && p->p_prison != NULL)
 625                 return (ENOSYS);
 626
 627         if (uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
 628                 return EINVAL;
 629         return ((*shmcalls[uap->which])(p, &uap->a2));
 630 }
 631
 632 void
 633 shmfork(p1, p2)
 634         struct proc *p1, *p2;
 635 {
 636         struct shmmap_state *shmmap_s;
 637         size_t size;
 638         int i;
 639
 640         size = shminfo.shmseg * sizeof(struct shmmap_state);
 641         shmmap_s = malloc(size, M_SHM, M_WAITOK);
 642         bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size);
 643         p2->p_vmspace->vm_shm = (caddr_t)shmmap_s;
 644         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
 645                 if (shmmap_s->shmid != -1)
 646                         shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++;
 647 }
 648
 649 void
 650 shmexit(p)
 651         struct proc *p;
 652 {
 653         struct shmmap_state *shmmap_s;
 654         int i;
 655
 656         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
 657         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
 658                 if (shmmap_s->shmid != -1)
 659                         shm_delete_mapping(p, shmmap_s);
 660         free((caddr_t)p->p_vmspace->vm_shm, M_SHM);
 661         p->p_vmspace->vm_shm = NULL;
 662 }
 663
 664 static void
 665 shmrealloc(void)
 666 {
 667         int i;
 668         struct shmid_ds *newsegs;
 669
 670         if (shmalloced >= shminfo.shmmni)
 671                 return;
 672
 673         newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
 674         if (newsegs == NULL)
 675                 return;
 676         for (i = 0; i < shmalloced; i++)
 677                 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
 678         for (; i < shminfo.shmmni; i++) {
 679                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
 680                 shmsegs[i].shm_perm.seq = 0;
 681         }
 682         free(shmsegs, M_SHM);
 683         shmsegs = newsegs;
 684         shmalloced = shminfo.shmmni;
 685 }
 686
 687 static void
 688 shminit(dummy)
 689         void *dummy;
 690 {
 691         int i;
 692
 693         shminfo.shmmax = shminfo.shmall * PAGE_SIZE;
 694         shmalloced = shminfo.shmmni;
 695         shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
 696         if (shmsegs == NULL)
 697                 panic("cannot allocate initial memory for sysvshm");
 698         for (i = 0; i < shmalloced; i++) {
 699                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
 700                 shmsegs[i].shm_perm.seq = 0;
 701         }
 702         shm_last_free = 0;
 703         shm_nused = 0;
 704         shm_committed = 0;
 705 }
 706 SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL);