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 1.3 2003/06/23 17:55:41 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(struct shmdt_args *uap)
 227 {
 228         struct proc *p = curproc;
 229         struct shmmap_state *shmmap_s;
 230         int i;
 231
 232         if (!jail_sysvipc_allowed && p->p_ucred->cr_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(struct shmat_args *uap)
 257 {
 258         struct proc *p = curproc;
 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 && p->p_ucred->cr_prison != NULL)
 269                 return (ENOSYS);
 270
 271         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
 272         if (shmmap_s == NULL) {
 273                 size = shminfo.shmseg * sizeof(struct shmmap_state);
 274                 shmmap_s = malloc(size, M_SHM, M_WAITOK);
 275                 for (i = 0; i < shminfo.shmseg; i++)
 276                         shmmap_s[i].shmid = -1;
 277                 p->p_vmspace->vm_shm = (caddr_t)shmmap_s;
 278         }
 279         shmseg = shm_find_segment_by_shmid(uap->shmid);
 280         if (shmseg == NULL)
 281                 return EINVAL;
 282         error = ipcperm(p, &shmseg->shm_perm,
 283             (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
 284         if (error)
 285                 return error;
 286         for (i = 0; i < shminfo.shmseg; i++) {
 287                 if (shmmap_s->shmid == -1)
 288                         break;
 289                 shmmap_s++;
 290         }
 291         if (i >= shminfo.shmseg)
 292                 return EMFILE;
 293         size = round_page(shmseg->shm_segsz);
 294 #ifdef VM_PROT_READ_IS_EXEC
 295         prot = VM_PROT_READ | VM_PROT_EXECUTE;
 296 #else
 297         prot = VM_PROT_READ;
 298 #endif
 299         if ((uap->shmflg & SHM_RDONLY) == 0)
 300                 prot |= VM_PROT_WRITE;
 301         flags = MAP_ANON | MAP_SHARED;
 302         if (uap->shmaddr) {
 303                 flags |= MAP_FIXED;
 304                 if (uap->shmflg & SHM_RND)
 305                         attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1);
 306                 else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0)
 307                         attach_va = (vm_offset_t)uap->shmaddr;
 308                 else
 309                         return EINVAL;
 310         } else {
 311                 /* This is just a hint to vm_map_find() about where to put it. */
 312                 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr + maxtsiz + maxdsiz);
 313         }
 314
 315         shm_handle = shmseg->shm_internal;
 316         vm_object_reference(shm_handle->shm_object);
 317         rv = vm_map_find(&p->p_vmspace->vm_map, shm_handle->shm_object,
 318                 0, &attach_va, size, (flags & MAP_FIXED)?0:1, prot, prot, 0);
 319         if (rv != KERN_SUCCESS) {
 320                 return ENOMEM;
 321         }
 322         vm_map_inherit(&p->p_vmspace->vm_map,
 323                 attach_va, attach_va + size, VM_INHERIT_SHARE);
 324
 325         shmmap_s->va = attach_va;
 326         shmmap_s->shmid = uap->shmid;
 327         shmseg->shm_lpid = p->p_pid;
 328         shmseg->shm_atime = time_second;
 329         shmseg->shm_nattch++;
 330         p->p_retval[0] = attach_va;
 331         return 0;
 332 }
 333
 334 struct oshmid_ds {
 335         struct  ipc_perm shm_perm;      /* operation perms */
 336         int     shm_segsz;              /* size of segment (bytes) */
 337         ushort  shm_cpid;               /* pid, creator */
 338         ushort  shm_lpid;               /* pid, last operation */
 339         short   shm_nattch;             /* no. of current attaches */
 340         time_t  shm_atime;              /* last attach time */
 341         time_t  shm_dtime;              /* last detach time */
 342         time_t  shm_ctime;              /* last change time */
 343         void    *shm_handle;            /* internal handle for shm segment */
 344 };
 345
 346 struct oshmctl_args {
 347         int shmid;
 348         int cmd;
 349         struct oshmid_ds *ubuf;
 350 };
 351
 352 static int
 353 oshmctl(p, uap)
 354         struct proc *p;
 355         struct oshmctl_args *uap;
 356 {
 357 #ifdef COMPAT_43
 358         int error;
 359         struct shmid_ds *shmseg;
 360         struct oshmid_ds outbuf;
 361
 362         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 363                 return (ENOSYS);
 364
 365         shmseg = shm_find_segment_by_shmid(uap->shmid);
 366         if (shmseg == NULL)
 367                 return EINVAL;
 368         switch (uap->cmd) {
 369         case IPC_STAT:
 370                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
 371                 if (error)
 372                         return error;
 373                 outbuf.shm_perm = shmseg->shm_perm;
 374                 outbuf.shm_segsz = shmseg->shm_segsz;
 375                 outbuf.shm_cpid = shmseg->shm_cpid;
 376                 outbuf.shm_lpid = shmseg->shm_lpid;
 377                 outbuf.shm_nattch = shmseg->shm_nattch;
 378                 outbuf.shm_atime = shmseg->shm_atime;
 379                 outbuf.shm_dtime = shmseg->shm_dtime;
 380                 outbuf.shm_ctime = shmseg->shm_ctime;
 381                 outbuf.shm_handle = shmseg->shm_internal;
 382                 error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf));
 383                 if (error)
 384                         return error;
 385                 break;
 386         default:
 387                 /* XXX casting to (sy_call_t *) is bogus, as usual. */
 388                 return ((sy_call_t *)shmctl)(uap);
 389         }
 390         return 0;
 391 #else
 392         return EINVAL;
 393 #endif
 394 }
 395
 396 #ifndef _SYS_SYSPROTO_H_
 397 struct shmctl_args {
 398         int shmid;
 399         int cmd;
 400         struct shmid_ds *buf;
 401 };
 402 #endif
 403
 404 int
 405 shmctl(struct shmctl_args *uap)
 406 {
 407         struct proc *p = curproc;
 408         int error;
 409         struct shmid_ds inbuf;
 410         struct shmid_ds *shmseg;
 411
 412         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 413                 return (ENOSYS);
 414
 415         shmseg = shm_find_segment_by_shmid(uap->shmid);
 416         if (shmseg == NULL)
 417                 return EINVAL;
 418         switch (uap->cmd) {
 419         case IPC_STAT:
 420                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
 421                 if (error)
 422                         return error;
 423                 error = copyout((caddr_t)shmseg, uap->buf, sizeof(inbuf));
 424                 if (error)
 425                         return error;
 426                 break;
 427         case IPC_SET:
 428                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
 429                 if (error)
 430                         return error;
 431                 error = copyin(uap->buf, (caddr_t)&inbuf, sizeof(inbuf));
 432                 if (error)
 433                         return error;
 434                 shmseg->shm_perm.uid = inbuf.shm_perm.uid;
 435                 shmseg->shm_perm.gid = inbuf.shm_perm.gid;
 436                 shmseg->shm_perm.mode =
 437                     (shmseg->shm_perm.mode & ~ACCESSPERMS) |
 438                     (inbuf.shm_perm.mode & ACCESSPERMS);
 439                 shmseg->shm_ctime = time_second;
 440                 break;
 441         case IPC_RMID:
 442                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
 443                 if (error)
 444                         return error;
 445                 shmseg->shm_perm.key = IPC_PRIVATE;
 446                 shmseg->shm_perm.mode |= SHMSEG_REMOVED;
 447                 if (shmseg->shm_nattch <= 0) {
 448                         shm_deallocate_segment(shmseg);
 449                         shm_last_free = IPCID_TO_IX(uap->shmid);
 450                 }
 451                 break;
 452 #if 0
 453         case SHM_LOCK:
 454         case SHM_UNLOCK:
 455 #endif
 456         default:
 457                 return EINVAL;
 458         }
 459         return 0;
 460 }
 461
 462 #ifndef _SYS_SYSPROTO_H_
 463 struct shmget_args {
 464         key_t key;
 465         size_t size;
 466         int shmflg;
 467 };
 468 #endif
 469
 470 static int
 471 shmget_existing(p, uap, mode, segnum)
 472         struct proc *p;
 473         struct shmget_args *uap;
 474         int mode;
 475         int segnum;
 476 {
 477         struct shmid_ds *shmseg;
 478         int error;
 479
 480         shmseg = &shmsegs[segnum];
 481         if (shmseg->shm_perm.mode & SHMSEG_REMOVED) {
 482                 /*
 483                  * This segment is in the process of being allocated.  Wait
 484                  * until it's done, and look the key up again (in case the
 485                  * allocation failed or it was freed).
 486                  */
 487                 shmseg->shm_perm.mode |= SHMSEG_WANTED;
 488                 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0);
 489                 if (error)
 490                         return error;
 491                 return EAGAIN;
 492         }
 493         if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
 494                 return EEXIST;
 495         error = ipcperm(p, &shmseg->shm_perm, mode);
 496         if (error)
 497                 return error;
 498         if (uap->size && uap->size > shmseg->shm_segsz)
 499                 return EINVAL;
 500         p->p_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
 501         return 0;
 502 }
 503
 504 static int
 505 shmget_allocate_segment(p, uap, mode)
 506         struct proc *p;
 507         struct shmget_args *uap;
 508         int mode;
 509 {
 510         int i, segnum, shmid, size;
 511         struct ucred *cred = p->p_ucred;
 512         struct shmid_ds *shmseg;
 513         struct shm_handle *shm_handle;
 514
 515         if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
 516                 return EINVAL;
 517         if (shm_nused >= shminfo.shmmni) /* any shmids left? */
 518                 return ENOSPC;
 519         size = round_page(uap->size);
 520         if (shm_committed + btoc(size) > shminfo.shmall)
 521                 return ENOMEM;
 522         if (shm_last_free < 0) {
 523                 shmrealloc();   /* maybe expand the shmsegs[] array */
 524                 for (i = 0; i < shmalloced; i++)
 525                         if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
 526                                 break;
 527                 if (i == shmalloced)
 528                         return ENOSPC;
 529                 segnum = i;
 530         } else  {
 531                 segnum = shm_last_free;
 532                 shm_last_free = -1;
 533         }
 534         shmseg = &shmsegs[segnum];
 535         /*
 536          * In case we sleep in malloc(), mark the segment present but deleted
 537          * so that noone else tries to create the same key.
 538          */
 539         shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
 540         shmseg->shm_perm.key = uap->key;
 541         shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff;
 542         shm_handle = (struct shm_handle *)
 543             malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK);
 544         shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
 545
 546         /*
 547          * We make sure that we have allocated a pager before we need
 548          * to.
 549          */
 550         if (shm_use_phys) {
 551                 shm_handle->shm_object =
 552                     vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0);
 553         } else {
 554                 shm_handle->shm_object =
 555                     vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0);
 556         }
 557         vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING);
 558         vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT);
 559
 560         shmseg->shm_internal = shm_handle;
 561         shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid;
 562         shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid;
 563         shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
 564             (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
 565         shmseg->shm_segsz = uap->size;
 566         shmseg->shm_cpid = p->p_pid;
 567         shmseg->shm_lpid = shmseg->shm_nattch = 0;
 568         shmseg->shm_atime = shmseg->shm_dtime = 0;
 569         shmseg->shm_ctime = time_second;
 570         shm_committed += btoc(size);
 571         shm_nused++;
 572         if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
 573                 /*
 574                  * Somebody else wanted this key while we were asleep.  Wake
 575                  * them up now.
 576                  */
 577                 shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
 578                 wakeup((caddr_t)shmseg);
 579         }
 580         p->p_retval[0] = shmid;
 581         return 0;
 582 }
 583
 584 int
 585 shmget(struct shmget_args *uap)
 586 {
 587         struct proc *p = curproc;
 588         int segnum, mode, error;
 589
 590         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 591                 return (ENOSYS);
 592
 593         mode = uap->shmflg & ACCESSPERMS;
 594         if (uap->key != IPC_PRIVATE) {
 595         again:
 596                 segnum = shm_find_segment_by_key(uap->key);
 597                 if (segnum >= 0) {
 598                         error = shmget_existing(p, uap, mode, segnum);
 599                         if (error == EAGAIN)
 600                                 goto again;
 601                         return error;
 602                 }
 603                 if ((uap->shmflg & IPC_CREAT) == 0)
 604                         return ENOENT;
 605         }
 606         return shmget_allocate_segment(p, uap, mode);
 607 }
 608
 609 /*
 610  *  shmsys_args(u_int which, int a2, ...) (VARARGS)
 611  */
 612 int
 613 shmsys(struct shmsys_args *uap)
 614 {
 615         struct proc *p = curproc;
 616
 617         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 618                 return (ENOSYS);
 619
 620         if (uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
 621                 return EINVAL;
 622         return ((*shmcalls[uap->which])(&uap->a2));
 623 }
 624
 625 void
 626 shmfork(p1, p2)
 627         struct proc *p1, *p2;
 628 {
 629         struct shmmap_state *shmmap_s;
 630         size_t size;
 631         int i;
 632
 633         size = shminfo.shmseg * sizeof(struct shmmap_state);
 634         shmmap_s = malloc(size, M_SHM, M_WAITOK);
 635         bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size);
 636         p2->p_vmspace->vm_shm = (caddr_t)shmmap_s;
 637         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
 638                 if (shmmap_s->shmid != -1)
 639                         shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++;
 640 }
 641
 642 void
 643 shmexit(p)
 644         struct proc *p;
 645 {
 646         struct shmmap_state *shmmap_s;
 647         int i;
 648
 649         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
 650         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
 651                 if (shmmap_s->shmid != -1)
 652                         shm_delete_mapping(p, shmmap_s);
 653         free((caddr_t)p->p_vmspace->vm_shm, M_SHM);
 654         p->p_vmspace->vm_shm = NULL;
 655 }
 656
 657 static void
 658 shmrealloc(void)
 659 {
 660         int i;
 661         struct shmid_ds *newsegs;
 662
 663         if (shmalloced >= shminfo.shmmni)
 664                 return;
 665
 666         newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
 667         if (newsegs == NULL)
 668                 return;
 669         for (i = 0; i < shmalloced; i++)
 670                 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
 671         for (; i < shminfo.shmmni; i++) {
 672                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
 673                 shmsegs[i].shm_perm.seq = 0;
 674         }
 675         free(shmsegs, M_SHM);
 676         shmsegs = newsegs;
 677         shmalloced = shminfo.shmmni;
 678 }
 679
 680 static void
 681 shminit(dummy)
 682         void *dummy;
 683 {
 684         int i;
 685
 686         shminfo.shmmax = shminfo.shmall * PAGE_SIZE;
 687         shmalloced = shminfo.shmmni;
 688         shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
 689         if (shmsegs == NULL)
 690                 panic("cannot allocate initial memory for sysvshm");
 691         for (i = 0; i < shmalloced; i++) {
 692                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
 693                 shmsegs[i].shm_perm.seq = 0;
 694         }
 695         shm_last_free = 0;
 696         shm_nused = 0;
 697         shm_committed = 0;
 698 }
 699 SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL);