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 1.5 2003/07/23 07:14:18 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 vmspace *vm, 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(struct vmspace *vm, struct shmmap_state *shmmap_s)
 196 {
 197         struct shmid_ds *shmseg;
 198         int segnum, result;
 199         size_t size;
 200
 201         segnum = IPCID_TO_IX(shmmap_s->shmid);
 202         shmseg = &shmsegs[segnum];
 203         size = round_page(shmseg->shm_segsz);
 204         result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size);
 205         if (result != KERN_SUCCESS)
 206                 return EINVAL;
 207         shmmap_s->shmid = -1;
 208         shmseg->shm_dtime = time_second;
 209         if ((--shmseg->shm_nattch <= 0) &&
 210             (shmseg->shm_perm.mode & SHMSEG_REMOVED)) {
 211                 shm_deallocate_segment(shmseg);
 212                 shm_last_free = segnum;
 213         }
 214         return 0;
 215 }
 216
 217 #ifndef _SYS_SYSPROTO_H_
 218 struct shmdt_args {
 219         void *shmaddr;
 220 };
 221 #endif
 222
 223 int
 224 shmdt(struct shmdt_args *uap)
 225 {
 226         struct proc *p = curproc;
 227         struct shmmap_state *shmmap_s;
 228         int i;
 229
 230         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 231                 return (ENOSYS);
 232
 233         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
 234         if (shmmap_s == NULL)
 235             return EINVAL;
 236         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
 237                 if (shmmap_s->shmid != -1 &&
 238                     shmmap_s->va == (vm_offset_t)uap->shmaddr)
 239                         break;
 240         if (i == shminfo.shmseg)
 241                 return EINVAL;
 242         return shm_delete_mapping(p->p_vmspace, shmmap_s);
 243 }
 244
 245 #ifndef _SYS_SYSPROTO_H_
 246 struct shmat_args {
 247         int shmid;
 248         void *shmaddr;
 249         int shmflg;
 250 };
 251 #endif
 252
 253 int
 254 shmat(struct shmat_args *uap)
 255 {
 256         struct proc *p = curproc;
 257         int error, i, flags;
 258         struct shmid_ds *shmseg;
 259         struct shmmap_state *shmmap_s = NULL;
 260         struct shm_handle *shm_handle;
 261         vm_offset_t attach_va;
 262         vm_prot_t prot;
 263         vm_size_t size;
 264         int rv;
 265
 266         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 267                 return (ENOSYS);
 268
 269         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
 270         if (shmmap_s == NULL) {
 271                 size = shminfo.shmseg * sizeof(struct shmmap_state);
 272                 shmmap_s = malloc(size, M_SHM, M_WAITOK);
 273                 for (i = 0; i < shminfo.shmseg; i++)
 274                         shmmap_s[i].shmid = -1;
 275                 p->p_vmspace->vm_shm = (caddr_t)shmmap_s;
 276         }
 277         shmseg = shm_find_segment_by_shmid(uap->shmid);
 278         if (shmseg == NULL)
 279                 return EINVAL;
 280         error = ipcperm(p, &shmseg->shm_perm,
 281             (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
 282         if (error)
 283                 return error;
 284         for (i = 0; i < shminfo.shmseg; i++) {
 285                 if (shmmap_s->shmid == -1)
 286                         break;
 287                 shmmap_s++;
 288         }
 289         if (i >= shminfo.shmseg)
 290                 return EMFILE;
 291         size = round_page(shmseg->shm_segsz);
 292 #ifdef VM_PROT_READ_IS_EXEC
 293         prot = VM_PROT_READ | VM_PROT_EXECUTE;
 294 #else
 295         prot = VM_PROT_READ;
 296 #endif
 297         if ((uap->shmflg & SHM_RDONLY) == 0)
 298                 prot |= VM_PROT_WRITE;
 299         flags = MAP_ANON | MAP_SHARED;
 300         if (uap->shmaddr) {
 301                 flags |= MAP_FIXED;
 302                 if (uap->shmflg & SHM_RND)
 303                         attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1);
 304                 else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0)
 305                         attach_va = (vm_offset_t)uap->shmaddr;
 306                 else
 307                         return EINVAL;
 308         } else {
 309                 /* This is just a hint to vm_map_find() about where to put it. */
 310                 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr + maxtsiz + maxdsiz);
 311         }
 312
 313         shm_handle = shmseg->shm_internal;
 314         vm_object_reference(shm_handle->shm_object);
 315         rv = vm_map_find(&p->p_vmspace->vm_map, shm_handle->shm_object,
 316                 0, &attach_va, size, (flags & MAP_FIXED)?0:1, prot, prot, 0);
 317         if (rv != KERN_SUCCESS) {
 318                 return ENOMEM;
 319         }
 320         vm_map_inherit(&p->p_vmspace->vm_map,
 321                 attach_va, attach_va + size, VM_INHERIT_SHARE);
 322
 323         shmmap_s->va = attach_va;
 324         shmmap_s->shmid = uap->shmid;
 325         shmseg->shm_lpid = p->p_pid;
 326         shmseg->shm_atime = time_second;
 327         shmseg->shm_nattch++;
 328         p->p_retval[0] = attach_va;
 329         return 0;
 330 }
 331
 332 struct oshmid_ds {
 333         struct  ipc_perm shm_perm;      /* operation perms */
 334         int     shm_segsz;              /* size of segment (bytes) */
 335         ushort  shm_cpid;               /* pid, creator */
 336         ushort  shm_lpid;               /* pid, last operation */
 337         short   shm_nattch;             /* no. of current attaches */
 338         time_t  shm_atime;              /* last attach time */
 339         time_t  shm_dtime;              /* last detach time */
 340         time_t  shm_ctime;              /* last change time */
 341         void    *shm_handle;            /* internal handle for shm segment */
 342 };
 343
 344 struct oshmctl_args {
 345         int shmid;
 346         int cmd;
 347         struct oshmid_ds *ubuf;
 348 };
 349
 350 static int
 351 oshmctl(p, uap)
 352         struct proc *p;
 353         struct oshmctl_args *uap;
 354 {
 355 #ifdef COMPAT_43
 356         int error;
 357         struct shmid_ds *shmseg;
 358         struct oshmid_ds outbuf;
 359
 360         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 361                 return (ENOSYS);
 362
 363         shmseg = shm_find_segment_by_shmid(uap->shmid);
 364         if (shmseg == NULL)
 365                 return EINVAL;
 366         switch (uap->cmd) {
 367         case IPC_STAT:
 368                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
 369                 if (error)
 370                         return error;
 371                 outbuf.shm_perm = shmseg->shm_perm;
 372                 outbuf.shm_segsz = shmseg->shm_segsz;
 373                 outbuf.shm_cpid = shmseg->shm_cpid;
 374                 outbuf.shm_lpid = shmseg->shm_lpid;
 375                 outbuf.shm_nattch = shmseg->shm_nattch;
 376                 outbuf.shm_atime = shmseg->shm_atime;
 377                 outbuf.shm_dtime = shmseg->shm_dtime;
 378                 outbuf.shm_ctime = shmseg->shm_ctime;
 379                 outbuf.shm_handle = shmseg->shm_internal;
 380                 error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf));
 381                 if (error)
 382                         return error;
 383                 break;
 384         default:
 385                 /* XXX casting to (sy_call_t *) is bogus, as usual. */
 386                 return ((sy_call_t *)shmctl)(uap);
 387         }
 388         return 0;
 389 #else
 390         return EINVAL;
 391 #endif
 392 }
 393
 394 #ifndef _SYS_SYSPROTO_H_
 395 struct shmctl_args {
 396         int shmid;
 397         int cmd;
 398         struct shmid_ds *buf;
 399 };
 400 #endif
 401
 402 int
 403 shmctl(struct shmctl_args *uap)
 404 {
 405         struct proc *p = curproc;
 406         int error;
 407         struct shmid_ds inbuf;
 408         struct shmid_ds *shmseg;
 409
 410         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 411                 return (ENOSYS);
 412
 413         shmseg = shm_find_segment_by_shmid(uap->shmid);
 414         if (shmseg == NULL)
 415                 return EINVAL;
 416         switch (uap->cmd) {
 417         case IPC_STAT:
 418                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
 419                 if (error)
 420                         return error;
 421                 error = copyout((caddr_t)shmseg, uap->buf, sizeof(inbuf));
 422                 if (error)
 423                         return error;
 424                 break;
 425         case IPC_SET:
 426                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
 427                 if (error)
 428                         return error;
 429                 error = copyin(uap->buf, (caddr_t)&inbuf, sizeof(inbuf));
 430                 if (error)
 431                         return error;
 432                 shmseg->shm_perm.uid = inbuf.shm_perm.uid;
 433                 shmseg->shm_perm.gid = inbuf.shm_perm.gid;
 434                 shmseg->shm_perm.mode =
 435                     (shmseg->shm_perm.mode & ~ACCESSPERMS) |
 436                     (inbuf.shm_perm.mode & ACCESSPERMS);
 437                 shmseg->shm_ctime = time_second;
 438                 break;
 439         case IPC_RMID:
 440                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
 441                 if (error)
 442                         return error;
 443                 shmseg->shm_perm.key = IPC_PRIVATE;
 444                 shmseg->shm_perm.mode |= SHMSEG_REMOVED;
 445                 if (shmseg->shm_nattch <= 0) {
 446                         shm_deallocate_segment(shmseg);
 447                         shm_last_free = IPCID_TO_IX(uap->shmid);
 448                 }
 449                 break;
 450 #if 0
 451         case SHM_LOCK:
 452         case SHM_UNLOCK:
 453 #endif
 454         default:
 455                 return EINVAL;
 456         }
 457         return 0;
 458 }
 459
 460 #ifndef _SYS_SYSPROTO_H_
 461 struct shmget_args {
 462         key_t key;
 463         size_t size;
 464         int shmflg;
 465 };
 466 #endif
 467
 468 static int
 469 shmget_existing(p, uap, mode, segnum)
 470         struct proc *p;
 471         struct shmget_args *uap;
 472         int mode;
 473         int segnum;
 474 {
 475         struct shmid_ds *shmseg;
 476         int error;
 477
 478         shmseg = &shmsegs[segnum];
 479         if (shmseg->shm_perm.mode & SHMSEG_REMOVED) {
 480                 /*
 481                  * This segment is in the process of being allocated.  Wait
 482                  * until it's done, and look the key up again (in case the
 483                  * allocation failed or it was freed).
 484                  */
 485                 shmseg->shm_perm.mode |= SHMSEG_WANTED;
 486                 error = tsleep((caddr_t)shmseg, PCATCH, "shmget", 0);
 487                 if (error)
 488                         return error;
 489                 return EAGAIN;
 490         }
 491         if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
 492                 return EEXIST;
 493         error = ipcperm(p, &shmseg->shm_perm, mode);
 494         if (error)
 495                 return error;
 496         if (uap->size && uap->size > shmseg->shm_segsz)
 497                 return EINVAL;
 498         p->p_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
 499         return 0;
 500 }
 501
 502 static int
 503 shmget_allocate_segment(p, uap, mode)
 504         struct proc *p;
 505         struct shmget_args *uap;
 506         int mode;
 507 {
 508         int i, segnum, shmid, size;
 509         struct ucred *cred = p->p_ucred;
 510         struct shmid_ds *shmseg;
 511         struct shm_handle *shm_handle;
 512
 513         if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
 514                 return EINVAL;
 515         if (shm_nused >= shminfo.shmmni) /* any shmids left? */
 516                 return ENOSPC;
 517         size = round_page(uap->size);
 518         if (shm_committed + btoc(size) > shminfo.shmall)
 519                 return ENOMEM;
 520         if (shm_last_free < 0) {
 521                 shmrealloc();   /* maybe expand the shmsegs[] array */
 522                 for (i = 0; i < shmalloced; i++)
 523                         if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
 524                                 break;
 525                 if (i == shmalloced)
 526                         return ENOSPC;
 527                 segnum = i;
 528         } else  {
 529                 segnum = shm_last_free;
 530                 shm_last_free = -1;
 531         }
 532         shmseg = &shmsegs[segnum];
 533         /*
 534          * In case we sleep in malloc(), mark the segment present but deleted
 535          * so that noone else tries to create the same key.
 536          */
 537         shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
 538         shmseg->shm_perm.key = uap->key;
 539         shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff;
 540         shm_handle = (struct shm_handle *)
 541             malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK);
 542         shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
 543
 544         /*
 545          * We make sure that we have allocated a pager before we need
 546          * to.
 547          */
 548         if (shm_use_phys) {
 549                 shm_handle->shm_object =
 550                     vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0);
 551         } else {
 552                 shm_handle->shm_object =
 553                     vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0);
 554         }
 555         vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING);
 556         vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT);
 557
 558         shmseg->shm_internal = shm_handle;
 559         shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid;
 560         shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid;
 561         shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
 562             (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
 563         shmseg->shm_segsz = uap->size;
 564         shmseg->shm_cpid = p->p_pid;
 565         shmseg->shm_lpid = shmseg->shm_nattch = 0;
 566         shmseg->shm_atime = shmseg->shm_dtime = 0;
 567         shmseg->shm_ctime = time_second;
 568         shm_committed += btoc(size);
 569         shm_nused++;
 570         if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
 571                 /*
 572                  * Somebody else wanted this key while we were asleep.  Wake
 573                  * them up now.
 574                  */
 575                 shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
 576                 wakeup((caddr_t)shmseg);
 577         }
 578         p->p_retval[0] = shmid;
 579         return 0;
 580 }
 581
 582 int
 583 shmget(struct shmget_args *uap)
 584 {
 585         struct proc *p = curproc;
 586         int segnum, mode, error;
 587
 588         if (!jail_sysvipc_allowed && p->p_ucred->cr_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 /*
 608  *  shmsys_args(u_int which, int a2, ...) (VARARGS)
 609  */
 610 int
 611 shmsys(struct shmsys_args *uap)
 612 {
 613         struct proc *p = curproc;
 614
 615         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 616                 return (ENOSYS);
 617
 618         if (uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
 619                 return EINVAL;
 620         return ((*shmcalls[uap->which])(&uap->a2));
 621 }
 622
 623 void
 624 shmfork(p1, p2)
 625         struct proc *p1, *p2;
 626 {
 627         struct shmmap_state *shmmap_s;
 628         size_t size;
 629         int i;
 630
 631         size = shminfo.shmseg * sizeof(struct shmmap_state);
 632         shmmap_s = malloc(size, M_SHM, M_WAITOK);
 633         bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size);
 634         p2->p_vmspace->vm_shm = (caddr_t)shmmap_s;
 635         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
 636                 if (shmmap_s->shmid != -1)
 637                         shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++;
 638 }
 639
 640 void
 641 shmexit(struct vmspace *vm)
 642 {
 643         struct shmmap_state *base, *shm;
 644         int i;
 645
 646         if ((base = (struct shmmap_state *)vm->vm_shm) != NULL) {
 647                 vm->vm_shm = NULL;
 648                 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) {
 649                         if (shm->shmid != -1)
 650                                 shm_delete_mapping(vm, shm);
 651                 }
 652                 free(base, M_SHM);
 653         }
 654 }
 655
 656 static void
 657 shmrealloc(void)
 658 {
 659         int i;
 660         struct shmid_ds *newsegs;
 661
 662         if (shmalloced >= shminfo.shmmni)
 663                 return;
 664
 665         newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
 666         if (newsegs == NULL)
 667                 return;
 668         for (i = 0; i < shmalloced; i++)
 669                 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
 670         for (; i < shminfo.shmmni; i++) {
 671                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
 672                 shmsegs[i].shm_perm.seq = 0;
 673         }
 674         free(shmsegs, M_SHM);
 675         shmsegs = newsegs;
 676         shmalloced = shminfo.shmmni;
 677 }
 678
 679 static void
 680 shminit(dummy)
 681         void *dummy;
 682 {
 683         int i;
 684
 685         shminfo.shmmax = shminfo.shmall * PAGE_SIZE;
 686         shmalloced = shminfo.shmmni;
 687         shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
 688         if (shmsegs == NULL)
 689                 panic("cannot allocate initial memory for sysvshm");
 690         for (i = 0; i < shmalloced; i++) {
 691                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
 692                 shmsegs[i].shm_perm.seq = 0;
 693         }
 694         shm_last_free = 0;
 695         shm_nused = 0;
 696         shm_committed = 0;
 697 }
 698 SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL);