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 1.2 2003/06/17 04:28:41 dillon Exp $ */
   3 /*      $NetBSD: sysv_shm.c,v 1.23 1994/07/04 23:25:12 glass Exp $      */
   4
   5 /*
   6  * Copyright (c) 1994 Adam Glass and Charles Hannum.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by Adam Glass and Charles
  19  *      Hannum.
  20  * 4. The names of the authors may not be used to endorse or promote products
  21  *    derived from this software without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
  24  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  25  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  26  * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  27  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  28  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  29  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  30  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  31  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  32  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  33  */
  34
  35 #include "opt_compat.h"
  36 #include "opt_sysvipc.h"
  37
  38 #include <sys/param.h>
  39 #include <sys/systm.h>
  40 #include <sys/sysproto.h>
  41 #include <sys/kernel.h>
  42 #include <sys/sysctl.h>
  43 #include <sys/shm.h>
  44 #include <sys/proc.h>
  45 #include <sys/malloc.h>
  46 #include <sys/mman.h>
  47 #include <sys/stat.h>
  48 #include <sys/sysent.h>
  49 #include <sys/jail.h>
  50
  51 #include <vm/vm.h>
  52 #include <vm/vm_param.h>
  53 #include <sys/lock.h>
  54 #include <vm/pmap.h>
  55 #include <vm/vm_object.h>
  56 #include <vm/vm_map.h>
  57 #include <vm/vm_page.h>
  58 #include <vm/vm_pager.h>
  59
  60 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments");
  61
  62 struct oshmctl_args;
  63 static int 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       8192    /* note: sysv shared memory is swap backed */
 105 #endif
 106 #ifndef SHMMAX
 107 #define SHMMAX  (SHMMAXPGS*PAGE_SIZE)
 108 #endif
 109 #ifndef SHMMIN
 110 #define SHMMIN  1
 111 #endif
 112 #ifndef SHMMNI
 113 #define SHMMNI  192
 114 #endif
 115 #ifndef SHMSEG
 116 #define SHMSEG  128
 117 #endif
 118 #ifndef SHMALL
 119 #define SHMALL  (SHMMAXPGS)
 120 #endif
 121
 122 struct  shminfo shminfo = {
 123         SHMMAX,
 124         SHMMIN,
 125         SHMMNI,
 126         SHMSEG,
 127         SHMALL
 128 };
 129
 130 static int shm_use_phys;
 131
 132 TUNABLE_INT("kern.ipc.shmmin", &shminfo.shmmin);
 133 TUNABLE_INT("kern.ipc.shmmni", &shminfo.shmmni);
 134 TUNABLE_INT("kern.ipc.shmseg", &shminfo.shmseg);
 135 TUNABLE_INT("kern.ipc.shmmaxpgs", &shminfo.shmall);
 136 TUNABLE_INT("kern.ipc.shm_use_phys", &shm_use_phys);
 137
 138 SYSCTL_DECL(_kern_ipc);
 139 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, "");
 140 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, "");
 141 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0, "");
 142 SYSCTL_INT(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RW, &shminfo.shmseg, 0, "");
 143 SYSCTL_INT(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, "");
 144 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, &shm_use_phys, 0, "");
 145
 146 static int
 147 shm_find_segment_by_key(key)
 148         key_t key;
 149 {
 150         int i;
 151
 152         for (i = 0; i < shmalloced; i++)
 153                 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) &&
 154                     shmsegs[i].shm_perm.key == key)
 155                         return i;
 156         return -1;
 157 }
 158
 159 static struct shmid_ds *
 160 shm_find_segment_by_shmid(shmid)
 161         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(shmseg)
 179         struct shmid_ds *shmseg;
 180 {
 181         struct shm_handle *shm_handle;
 182         size_t size;
 183
 184         shm_handle = shmseg->shm_internal;
 185         vm_object_deallocate(shm_handle->shm_object);
 186         free((caddr_t)shm_handle, M_SHM);
 187         shmseg->shm_internal = NULL;
 188         size = round_page(shmseg->shm_segsz);
 189         shm_committed -= btoc(size);
 190         shm_nused--;
 191         shmseg->shm_perm.mode = SHMSEG_FREE;
 192 }
 193
 194 static int
 195 shm_delete_mapping(p, shmmap_s)
 196         struct proc *p;
 197         struct shmmap_state *shmmap_s;
 198 {
 199         struct shmid_ds *shmseg;
 200         int segnum, result;
 201         size_t size;
 202
 203         segnum = IPCID_TO_IX(shmmap_s->shmid);
 204         shmseg = &shmsegs[segnum];
 205         size = round_page(shmseg->shm_segsz);
 206         result = vm_map_remove(&p->p_vmspace->vm_map, shmmap_s->va, shmmap_s->va + size);
 207         if (result != KERN_SUCCESS)
 208                 return EINVAL;
 209         shmmap_s->shmid = -1;
 210         shmseg->shm_dtime = time_second;
 211         if ((--shmseg->shm_nattch <= 0) &&
 212             (shmseg->shm_perm.mode & SHMSEG_REMOVED)) {
 213                 shm_deallocate_segment(shmseg);
 214                 shm_last_free = segnum;
 215         }
 216         return 0;
 217 }
 218
 219 #ifndef _SYS_SYSPROTO_H_
 220 struct shmdt_args {
 221         void *shmaddr;
 222 };
 223 #endif
 224
 225 int
 226 shmdt(p, uap)
 227         struct proc *p;
 228         struct shmdt_args *uap;
 229 {
 230         struct shmmap_state *shmmap_s;
 231         int i;
 232
 233         if (!jail_sysvipc_allowed && p->p_prison != NULL)
 234                 return (ENOSYS);
 235
 236         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
 237         if (shmmap_s == NULL)
 238             return EINVAL;
 239         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
 240                 if (shmmap_s->shmid != -1 &&
 241                     shmmap_s->va == (vm_offset_t)uap->shmaddr)
 242                         break;
 243         if (i == shminfo.shmseg)
 244                 return EINVAL;
 245         return shm_delete_mapping(p, shmmap_s);
 246 }
 247
 248 #ifndef _SYS_SYSPROTO_H_
 249 struct shmat_args {
 250         int shmid;
 251         void *shmaddr;
 252         int shmflg;
 253 };
 254 #endif
 255
 256 int
 257 shmat(p, uap)
 258         struct proc *p;
 259         struct shmat_args *uap;
 260 {
 261         int error, i, flags;
 262         struct shmid_ds *shmseg;
 263         struct shmmap_state *shmmap_s = NULL;
 264         struct shm_handle *shm_handle;
 265         vm_offset_t attach_va;
 266         vm_prot_t prot;
 267         vm_size_t size;
 268         int rv;
 269
 270         if (!jail_sysvipc_allowed && p->p_prison != NULL)
 271                 return (ENOSYS);
 272
 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 = malloc(size, M_SHM, M_WAITOK);
 277                 for (i = 0; i < shminfo.shmseg; i++)
 278                         shmmap_s[i].shmid = -1;
 279                 p->p_vmspace->vm_shm = (caddr_t)shmmap_s;
 280         }
 281         shmseg = shm_find_segment_by_shmid(uap->shmid);
 282         if (shmseg == NULL)
 283                 return EINVAL;
 284         error = ipcperm(p, &shmseg->shm_perm,
 285             (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
 286         if (error)
 287                 return error;
 288         for (i = 0; i < shminfo.shmseg; i++) {
 289                 if (shmmap_s->shmid == -1)
 290                         break;
 291                 shmmap_s++;
 292         }
 293         if (i >= shminfo.shmseg)
 294                 return EMFILE;
 295         size = round_page(shmseg->shm_segsz);
 296 #ifdef VM_PROT_READ_IS_EXEC
 297         prot = VM_PROT_READ | VM_PROT_EXECUTE;
 298 #else
 299         prot = VM_PROT_READ;
 300 #endif
 301         if ((uap->shmflg & SHM_RDONLY) == 0)
 302                 prot |= VM_PROT_WRITE;
 303         flags = MAP_ANON | MAP_SHARED;
 304         if (uap->shmaddr) {
 305                 flags |= MAP_FIXED;
 306                 if (uap->shmflg & SHM_RND)
 307                         attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1);
 308                 else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0)
 309                         attach_va = (vm_offset_t)uap->shmaddr;
 310                 else
 311                         return EINVAL;
 312         } else {
 313                 /* This is just a hint to vm_map_find() about where to put it. */
 314                 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr + maxtsiz + maxdsiz);
 315         }
 316
 317         shm_handle = shmseg->shm_internal;
 318         vm_object_reference(shm_handle->shm_object);
 319         rv = vm_map_find(&p->p_vmspace->vm_map, shm_handle->shm_object,
 320                 0, &attach_va, size, (flags & MAP_FIXED)?0:1, prot, prot, 0);
 321         if (rv != KERN_SUCCESS) {
 322                 return ENOMEM;
 323         }
 324         vm_map_inherit(&p->p_vmspace->vm_map,
 325                 attach_va, attach_va + size, VM_INHERIT_SHARE);
 326
 327         shmmap_s->va = attach_va;
 328         shmmap_s->shmid = uap->shmid;
 329         shmseg->shm_lpid = p->p_pid;
 330         shmseg->shm_atime = time_second;
 331         shmseg->shm_nattch++;
 332         p->p_retval[0] = attach_va;
 333         return 0;
 334 }
 335
 336 struct oshmid_ds {
 337         struct  ipc_perm shm_perm;      /* operation perms */
 338         int     shm_segsz;              /* size of segment (bytes) */
 339         ushort  shm_cpid;               /* pid, creator */
 340         ushort  shm_lpid;               /* pid, last operation */
 341         short   shm_nattch;             /* no. of current attaches */
 342         time_t  shm_atime;              /* last attach time */
 343         time_t  shm_dtime;              /* last detach time */
 344         time_t  shm_ctime;              /* last change time */
 345         void    *shm_handle;            /* internal handle for shm segment */
 346 };
 347
 348 struct oshmctl_args {
 349         int shmid;
 350         int cmd;
 351         struct oshmid_ds *ubuf;
 352 };
 353
 354 static int
 355 oshmctl(p, uap)
 356         struct proc *p;
 357         struct oshmctl_args *uap;
 358 {
 359 #ifdef COMPAT_43
 360         int error;
 361         struct shmid_ds *shmseg;
 362         struct oshmid_ds outbuf;
 363
 364         if (!jail_sysvipc_allowed && p->p_prison != NULL)
 365                 return (ENOSYS);
 366
 367         shmseg = shm_find_segment_by_shmid(uap->shmid);
 368         if (shmseg == NULL)
 369                 return EINVAL;
 370         switch (uap->cmd) {
 371         case IPC_STAT:
 372                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
 373                 if (error)
 374                         return error;
 375                 outbuf.shm_perm = shmseg->shm_perm;
 376                 outbuf.shm_segsz = shmseg->shm_segsz;
 377                 outbuf.shm_cpid = shmseg->shm_cpid;
 378                 outbuf.shm_lpid = shmseg->shm_lpid;
 379                 outbuf.shm_nattch = shmseg->shm_nattch;
 380                 outbuf.shm_atime = shmseg->shm_atime;
 381                 outbuf.shm_dtime = shmseg->shm_dtime;
 382                 outbuf.shm_ctime = shmseg->shm_ctime;
 383                 outbuf.shm_handle = shmseg->shm_internal;
 384                 error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf));
 385                 if (error)
 386                         return error;
 387                 break;
 388         default:
 389                 /* XXX casting to (sy_call_t *) is bogus, as usual. */
 390                 return ((sy_call_t *)shmctl)(p, uap);
 391         }
 392         return 0;
 393 #else
 394         return EINVAL;
 395 #endif
 396 }
 397
 398 #ifndef _SYS_SYSPROTO_H_
 399 struct shmctl_args {
 400         int shmid;
 401         int cmd;
 402         struct shmid_ds *buf;
 403 };
 404 #endif
 405
 406 int
 407 shmctl(p, uap)
 408         struct proc *p;
 409         struct shmctl_args *uap;
 410 {
 411         int error;
 412         struct shmid_ds inbuf;
 413         struct shmid_ds *shmseg;
 414
 415         if (!jail_sysvipc_allowed && p->p_prison != NULL)
 416                 return (ENOSYS);
 417
 418         shmseg = shm_find_segment_by_shmid(uap->shmid);
 419         if (shmseg == NULL)
 420                 return EINVAL;
 421         switch (uap->cmd) {
 422         case IPC_STAT:
 423                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
 424                 if (error)
 425                         return error;
 426                 error = copyout((caddr_t)shmseg, uap->buf, sizeof(inbuf));
 427                 if (error)
 428                         return error;
 429                 break;
 430         case IPC_SET:
 431                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
 432                 if (error)
 433                         return error;
 434                 error = copyin(uap->buf, (caddr_t)&inbuf, sizeof(inbuf));
 435                 if (error)
 436                         return error;
 437                 shmseg->shm_perm.uid = inbuf.shm_perm.uid;
 438                 shmseg->shm_perm.gid = inbuf.shm_perm.gid;
 439                 shmseg->shm_perm.mode =
 440                     (shmseg->shm_perm.mode & ~ACCESSPERMS) |
 441                     (inbuf.shm_perm.mode & ACCESSPERMS);
 442                 shmseg->shm_ctime = time_second;
 443                 break;
 444         case IPC_RMID:
 445                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
 446                 if (error)
 447                         return error;
 448                 shmseg->shm_perm.key = IPC_PRIVATE;
 449                 shmseg->shm_perm.mode |= SHMSEG_REMOVED;
 450                 if (shmseg->shm_nattch <= 0) {
 451                         shm_deallocate_segment(shmseg);
 452                         shm_last_free = IPCID_TO_IX(uap->shmid);
 453                 }
 454                 break;
 455 #if 0
 456         case SHM_LOCK:
 457         case SHM_UNLOCK:
 458 #endif
 459         default:
 460                 return EINVAL;
 461         }
 462         return 0;
 463 }
 464
 465 #ifndef _SYS_SYSPROTO_H_
 466 struct shmget_args {
 467         key_t key;
 468         size_t size;
 469         int shmflg;
 470 };
 471 #endif
 472
 473 static int
 474 shmget_existing(p, uap, mode, segnum)
 475         struct proc *p;
 476         struct shmget_args *uap;
 477         int mode;
 478         int segnum;
 479 {
 480         struct shmid_ds *shmseg;
 481         int error;
 482
 483         shmseg = &shmsegs[segnum];
 484         if (shmseg->shm_perm.mode & SHMSEG_REMOVED) {
 485                 /*
 486                  * This segment is in the process of being allocated.  Wait
 487                  * until it's done, and look the key up again (in case the
 488                  * allocation failed or it was freed).
 489                  */
 490                 shmseg->shm_perm.mode |= SHMSEG_WANTED;
 491                 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0);
 492                 if (error)
 493                         return error;
 494                 return EAGAIN;
 495         }
 496         if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
 497                 return EEXIST;
 498         error = ipcperm(p, &shmseg->shm_perm, mode);
 499         if (error)
 500                 return error;
 501         if (uap->size && uap->size > shmseg->shm_segsz)
 502                 return EINVAL;
 503         p->p_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
 504         return 0;
 505 }
 506
 507 static int
 508 shmget_allocate_segment(p, uap, mode)
 509         struct proc *p;
 510         struct shmget_args *uap;
 511         int mode;
 512 {
 513         int i, segnum, shmid, size;
 514         struct ucred *cred = p->p_ucred;
 515         struct shmid_ds *shmseg;
 516         struct shm_handle *shm_handle;
 517
 518         if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
 519                 return EINVAL;
 520         if (shm_nused >= shminfo.shmmni) /* any shmids left? */
 521                 return ENOSPC;
 522         size = round_page(uap->size);
 523         if (shm_committed + btoc(size) > shminfo.shmall)
 524                 return ENOMEM;
 525         if (shm_last_free < 0) {
 526                 shmrealloc();   /* maybe expand the shmsegs[] array */
 527                 for (i = 0; i < shmalloced; i++)
 528                         if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
 529                                 break;
 530                 if (i == shmalloced)
 531                         return ENOSPC;
 532                 segnum = i;
 533         } else  {
 534                 segnum = shm_last_free;
 535                 shm_last_free = -1;
 536         }
 537         shmseg = &shmsegs[segnum];
 538         /*
 539          * In case we sleep in malloc(), mark the segment present but deleted
 540          * so that noone else tries to create the same key.
 541          */
 542         shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
 543         shmseg->shm_perm.key = uap->key;
 544         shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff;
 545         shm_handle = (struct shm_handle *)
 546             malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK);
 547         shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
 548
 549         /*
 550          * We make sure that we have allocated a pager before we need
 551          * to.
 552          */
 553         if (shm_use_phys) {
 554                 shm_handle->shm_object =
 555                     vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0);
 556         } else {
 557                 shm_handle->shm_object =
 558                     vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0);
 559         }
 560         vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING);
 561         vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT);
 562
 563         shmseg->shm_internal = shm_handle;
 564         shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid;
 565         shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid;
 566         shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
 567             (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
 568         shmseg->shm_segsz = uap->size;
 569         shmseg->shm_cpid = p->p_pid;
 570         shmseg->shm_lpid = shmseg->shm_nattch = 0;
 571         shmseg->shm_atime = shmseg->shm_dtime = 0;
 572         shmseg->shm_ctime = time_second;
 573         shm_committed += btoc(size);
 574         shm_nused++;
 575         if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
 576                 /*
 577                  * Somebody else wanted this key while we were asleep.  Wake
 578                  * them up now.
 579                  */
 580                 shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
 581                 wakeup((caddr_t)shmseg);
 582         }
 583         p->p_retval[0] = shmid;
 584         return 0;
 585 }
 586
 587 int
 588 shmget(p, uap)
 589         struct proc *p;
 590         struct shmget_args *uap;
 591 {
 592         int segnum, mode, error;
 593
 594         if (!jail_sysvipc_allowed && p->p_prison != NULL)
 595                 return (ENOSYS);
 596
 597         mode = uap->shmflg & ACCESSPERMS;
 598         if (uap->key != IPC_PRIVATE) {
 599         again:
 600                 segnum = shm_find_segment_by_key(uap->key);
 601                 if (segnum >= 0) {
 602                         error = shmget_existing(p, uap, mode, segnum);
 603                         if (error == EAGAIN)
 604                                 goto again;
 605                         return error;
 606                 }
 607                 if ((uap->shmflg & IPC_CREAT) == 0)
 608                         return ENOENT;
 609         }
 610         return shmget_allocate_segment(p, uap, mode);
 611 }
 612
 613 int
 614 shmsys(p, uap)
 615         struct proc *p;
 616         /* XXX actually varargs. */
 617         struct shmsys_args /* {
 618                 u_int   which;
 619                 int     a2;
 620                 int     a3;
 621                 int     a4;
 622         } */ *uap;
 623 {
 624
 625         if (!jail_sysvipc_allowed && p->p_prison != NULL)
 626                 return (ENOSYS);
 627
 628         if (uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
 629                 return EINVAL;
 630         return ((*shmcalls[uap->which])(p, &uap->a2));
 631 }
 632
 633 void
 634 shmfork(p1, p2)
 635         struct proc *p1, *p2;
 636 {
 637         struct shmmap_state *shmmap_s;
 638         size_t size;
 639         int i;
 640
 641         size = shminfo.shmseg * sizeof(struct shmmap_state);
 642         shmmap_s = malloc(size, M_SHM, M_WAITOK);
 643         bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size);
 644         p2->p_vmspace->vm_shm = (caddr_t)shmmap_s;
 645         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
 646                 if (shmmap_s->shmid != -1)
 647                         shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++;
 648 }
 649
 650 void
 651 shmexit(p)
 652         struct proc *p;
 653 {
 654         struct shmmap_state *shmmap_s;
 655         int i;
 656
 657         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
 658         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
 659                 if (shmmap_s->shmid != -1)
 660                         shm_delete_mapping(p, shmmap_s);
 661         free((caddr_t)p->p_vmspace->vm_shm, M_SHM);
 662         p->p_vmspace->vm_shm = NULL;
 663 }
 664
 665 static void
 666 shmrealloc(void)
 667 {
 668         int i;
 669         struct shmid_ds *newsegs;
 670
 671         if (shmalloced >= shminfo.shmmni)
 672                 return;
 673
 674         newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
 675         if (newsegs == NULL)
 676                 return;
 677         for (i = 0; i < shmalloced; i++)
 678                 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
 679         for (; i < shminfo.shmmni; i++) {
 680                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
 681                 shmsegs[i].shm_perm.seq = 0;
 682         }
 683         free(shmsegs, M_SHM);
 684         shmsegs = newsegs;
 685         shmalloced = shminfo.shmmni;
 686 }
 687
 688 static void
 689 shminit(dummy)
 690         void *dummy;
 691 {
 692         int i;
 693
 694         shminfo.shmmax = shminfo.shmall * PAGE_SIZE;
 695         shmalloced = shminfo.shmmni;
 696         shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
 697         if (shmsegs == NULL)
 698                 panic("cannot allocate initial memory for sysvshm");
 699         for (i = 0; i < shmalloced; i++) {
 700                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
 701                 shmsegs[i].shm_perm.seq = 0;
 702         }
 703         shm_last_free = 0;
 704         shm_nused = 0;
 705         shm_committed = 0;
 706 }
 707 SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL);