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 1.6 2003/07/24 01:41:25 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 int
 218 shmdt(struct shmdt_args *uap)
 219 {
 220         struct proc *p = curproc;
 221         struct shmmap_state *shmmap_s;
 222         int i;
 223
 224         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 225                 return (ENOSYS);
 226
 227         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
 228         if (shmmap_s == NULL)
 229             return EINVAL;
 230         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
 231                 if (shmmap_s->shmid != -1 &&
 232                     shmmap_s->va == (vm_offset_t)uap->shmaddr)
 233                         break;
 234         if (i == shminfo.shmseg)
 235                 return EINVAL;
 236         return shm_delete_mapping(p->p_vmspace, shmmap_s);
 237 }
 238
 239 int
 240 shmat(struct shmat_args *uap)
 241 {
 242         struct proc *p = curproc;
 243         int error, i, flags;
 244         struct shmid_ds *shmseg;
 245         struct shmmap_state *shmmap_s = NULL;
 246         struct shm_handle *shm_handle;
 247         vm_offset_t attach_va;
 248         vm_prot_t prot;
 249         vm_size_t size;
 250         int rv;
 251
 252         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 253                 return (ENOSYS);
 254
 255         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
 256         if (shmmap_s == NULL) {
 257                 size = shminfo.shmseg * sizeof(struct shmmap_state);
 258                 shmmap_s = malloc(size, M_SHM, M_WAITOK);
 259                 for (i = 0; i < shminfo.shmseg; i++)
 260                         shmmap_s[i].shmid = -1;
 261                 p->p_vmspace->vm_shm = (caddr_t)shmmap_s;
 262         }
 263         shmseg = shm_find_segment_by_shmid(uap->shmid);
 264         if (shmseg == NULL)
 265                 return EINVAL;
 266         error = ipcperm(p, &shmseg->shm_perm,
 267             (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
 268         if (error)
 269                 return error;
 270         for (i = 0; i < shminfo.shmseg; i++) {
 271                 if (shmmap_s->shmid == -1)
 272                         break;
 273                 shmmap_s++;
 274         }
 275         if (i >= shminfo.shmseg)
 276                 return EMFILE;
 277         size = round_page(shmseg->shm_segsz);
 278 #ifdef VM_PROT_READ_IS_EXEC
 279         prot = VM_PROT_READ | VM_PROT_EXECUTE;
 280 #else
 281         prot = VM_PROT_READ;
 282 #endif
 283         if ((uap->shmflg & SHM_RDONLY) == 0)
 284                 prot |= VM_PROT_WRITE;
 285         flags = MAP_ANON | MAP_SHARED;
 286         if (uap->shmaddr) {
 287                 flags |= MAP_FIXED;
 288                 if (uap->shmflg & SHM_RND)
 289                         attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1);
 290                 else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0)
 291                         attach_va = (vm_offset_t)uap->shmaddr;
 292                 else
 293                         return EINVAL;
 294         } else {
 295                 /* This is just a hint to vm_map_find() about where to put it. */
 296                 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr + maxtsiz + maxdsiz);
 297         }
 298
 299         shm_handle = shmseg->shm_internal;
 300         vm_object_reference(shm_handle->shm_object);
 301         rv = vm_map_find(&p->p_vmspace->vm_map, shm_handle->shm_object,
 302                 0, &attach_va, size, (flags & MAP_FIXED)?0:1, prot, prot, 0);
 303         if (rv != KERN_SUCCESS) {
 304                 return ENOMEM;
 305         }
 306         vm_map_inherit(&p->p_vmspace->vm_map,
 307                 attach_va, attach_va + size, VM_INHERIT_SHARE);
 308
 309         shmmap_s->va = attach_va;
 310         shmmap_s->shmid = uap->shmid;
 311         shmseg->shm_lpid = p->p_pid;
 312         shmseg->shm_atime = time_second;
 313         shmseg->shm_nattch++;
 314         p->p_retval[0] = attach_va;
 315         return 0;
 316 }
 317
 318 struct oshmid_ds {
 319         struct  ipc_perm shm_perm;      /* operation perms */
 320         int     shm_segsz;              /* size of segment (bytes) */
 321         ushort  shm_cpid;               /* pid, creator */
 322         ushort  shm_lpid;               /* pid, last operation */
 323         short   shm_nattch;             /* no. of current attaches */
 324         time_t  shm_atime;              /* last attach time */
 325         time_t  shm_dtime;              /* last detach time */
 326         time_t  shm_ctime;              /* last change time */
 327         void    *shm_handle;            /* internal handle for shm segment */
 328 };
 329
 330 struct oshmctl_args {
 331         int shmid;
 332         int cmd;
 333         struct oshmid_ds *ubuf;
 334 };
 335
 336 static int
 337 oshmctl(p, uap)
 338         struct proc *p;
 339         struct oshmctl_args *uap;
 340 {
 341 #ifdef COMPAT_43
 342         int error;
 343         struct shmid_ds *shmseg;
 344         struct oshmid_ds outbuf;
 345
 346         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 347                 return (ENOSYS);
 348
 349         shmseg = shm_find_segment_by_shmid(uap->shmid);
 350         if (shmseg == NULL)
 351                 return EINVAL;
 352         switch (uap->cmd) {
 353         case IPC_STAT:
 354                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
 355                 if (error)
 356                         return error;
 357                 outbuf.shm_perm = shmseg->shm_perm;
 358                 outbuf.shm_segsz = shmseg->shm_segsz;
 359                 outbuf.shm_cpid = shmseg->shm_cpid;
 360                 outbuf.shm_lpid = shmseg->shm_lpid;
 361                 outbuf.shm_nattch = shmseg->shm_nattch;
 362                 outbuf.shm_atime = shmseg->shm_atime;
 363                 outbuf.shm_dtime = shmseg->shm_dtime;
 364                 outbuf.shm_ctime = shmseg->shm_ctime;
 365                 outbuf.shm_handle = shmseg->shm_internal;
 366                 error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf));
 367                 if (error)
 368                         return error;
 369                 break;
 370         default:
 371                 /* XXX casting to (sy_call_t *) is bogus, as usual. */
 372                 return ((sy_call_t *)shmctl)(uap);
 373         }
 374         return 0;
 375 #else
 376         return EINVAL;
 377 #endif
 378 }
 379
 380 int
 381 shmctl(struct shmctl_args *uap)
 382 {
 383         struct proc *p = curproc;
 384         int error;
 385         struct shmid_ds inbuf;
 386         struct shmid_ds *shmseg;
 387
 388         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 389                 return (ENOSYS);
 390
 391         shmseg = shm_find_segment_by_shmid(uap->shmid);
 392         if (shmseg == NULL)
 393                 return EINVAL;
 394         switch (uap->cmd) {
 395         case IPC_STAT:
 396                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
 397                 if (error)
 398                         return error;
 399                 error = copyout((caddr_t)shmseg, uap->buf, sizeof(inbuf));
 400                 if (error)
 401                         return error;
 402                 break;
 403         case IPC_SET:
 404                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
 405                 if (error)
 406                         return error;
 407                 error = copyin(uap->buf, (caddr_t)&inbuf, sizeof(inbuf));
 408                 if (error)
 409                         return error;
 410                 shmseg->shm_perm.uid = inbuf.shm_perm.uid;
 411                 shmseg->shm_perm.gid = inbuf.shm_perm.gid;
 412                 shmseg->shm_perm.mode =
 413                     (shmseg->shm_perm.mode & ~ACCESSPERMS) |
 414                     (inbuf.shm_perm.mode & ACCESSPERMS);
 415                 shmseg->shm_ctime = time_second;
 416                 break;
 417         case IPC_RMID:
 418                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
 419                 if (error)
 420                         return error;
 421                 shmseg->shm_perm.key = IPC_PRIVATE;
 422                 shmseg->shm_perm.mode |= SHMSEG_REMOVED;
 423                 if (shmseg->shm_nattch <= 0) {
 424                         shm_deallocate_segment(shmseg);
 425                         shm_last_free = IPCID_TO_IX(uap->shmid);
 426                 }
 427                 break;
 428 #if 0
 429         case SHM_LOCK:
 430         case SHM_UNLOCK:
 431 #endif
 432         default:
 433                 return EINVAL;
 434         }
 435         return 0;
 436 }
 437
 438 static int
 439 shmget_existing(p, uap, mode, segnum)
 440         struct proc *p;
 441         struct shmget_args *uap;
 442         int mode;
 443         int segnum;
 444 {
 445         struct shmid_ds *shmseg;
 446         int error;
 447
 448         shmseg = &shmsegs[segnum];
 449         if (shmseg->shm_perm.mode & SHMSEG_REMOVED) {
 450                 /*
 451                  * This segment is in the process of being allocated.  Wait
 452                  * until it's done, and look the key up again (in case the
 453                  * allocation failed or it was freed).
 454                  */
 455                 shmseg->shm_perm.mode |= SHMSEG_WANTED;
 456                 error = tsleep((caddr_t)shmseg, PCATCH, "shmget", 0);
 457                 if (error)
 458                         return error;
 459                 return EAGAIN;
 460         }
 461         if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
 462                 return EEXIST;
 463         error = ipcperm(p, &shmseg->shm_perm, mode);
 464         if (error)
 465                 return error;
 466         if (uap->size && uap->size > shmseg->shm_segsz)
 467                 return EINVAL;
 468         p->p_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
 469         return 0;
 470 }
 471
 472 static int
 473 shmget_allocate_segment(p, uap, mode)
 474         struct proc *p;
 475         struct shmget_args *uap;
 476         int mode;
 477 {
 478         int i, segnum, shmid, size;
 479         struct ucred *cred = p->p_ucred;
 480         struct shmid_ds *shmseg;
 481         struct shm_handle *shm_handle;
 482
 483         if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
 484                 return EINVAL;
 485         if (shm_nused >= shminfo.shmmni) /* any shmids left? */
 486                 return ENOSPC;
 487         size = round_page(uap->size);
 488         if (shm_committed + btoc(size) > shminfo.shmall)
 489                 return ENOMEM;
 490         if (shm_last_free < 0) {
 491                 shmrealloc();   /* maybe expand the shmsegs[] array */
 492                 for (i = 0; i < shmalloced; i++)
 493                         if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
 494                                 break;
 495                 if (i == shmalloced)
 496                         return ENOSPC;
 497                 segnum = i;
 498         } else  {
 499                 segnum = shm_last_free;
 500                 shm_last_free = -1;
 501         }
 502         shmseg = &shmsegs[segnum];
 503         /*
 504          * In case we sleep in malloc(), mark the segment present but deleted
 505          * so that noone else tries to create the same key.
 506          */
 507         shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
 508         shmseg->shm_perm.key = uap->key;
 509         shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff;
 510         shm_handle = (struct shm_handle *)
 511             malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK);
 512         shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
 513
 514         /*
 515          * We make sure that we have allocated a pager before we need
 516          * to.
 517          */
 518         if (shm_use_phys) {
 519                 shm_handle->shm_object =
 520                     vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0);
 521         } else {
 522                 shm_handle->shm_object =
 523                     vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0);
 524         }
 525         vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING);
 526         vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT);
 527
 528         shmseg->shm_internal = shm_handle;
 529         shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid;
 530         shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid;
 531         shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
 532             (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
 533         shmseg->shm_segsz = uap->size;
 534         shmseg->shm_cpid = p->p_pid;
 535         shmseg->shm_lpid = shmseg->shm_nattch = 0;
 536         shmseg->shm_atime = shmseg->shm_dtime = 0;
 537         shmseg->shm_ctime = time_second;
 538         shm_committed += btoc(size);
 539         shm_nused++;
 540         if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
 541                 /*
 542                  * Somebody else wanted this key while we were asleep.  Wake
 543                  * them up now.
 544                  */
 545                 shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
 546                 wakeup((caddr_t)shmseg);
 547         }
 548         p->p_retval[0] = shmid;
 549         return 0;
 550 }
 551
 552 int
 553 shmget(struct shmget_args *uap)
 554 {
 555         struct proc *p = curproc;
 556         int segnum, mode, error;
 557
 558         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 559                 return (ENOSYS);
 560
 561         mode = uap->shmflg & ACCESSPERMS;
 562         if (uap->key != IPC_PRIVATE) {
 563         again:
 564                 segnum = shm_find_segment_by_key(uap->key);
 565                 if (segnum >= 0) {
 566                         error = shmget_existing(p, uap, mode, segnum);
 567                         if (error == EAGAIN)
 568                                 goto again;
 569                         return error;
 570                 }
 571                 if ((uap->shmflg & IPC_CREAT) == 0)
 572                         return ENOENT;
 573         }
 574         return shmget_allocate_segment(p, uap, mode);
 575 }
 576
 577 /*
 578  *  shmsys_args(u_int which, int a2, ...) (VARARGS)
 579  */
 580 int
 581 shmsys(struct shmsys_args *uap)
 582 {
 583         struct proc *p = curproc;
 584
 585         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 586                 return (ENOSYS);
 587
 588         if (uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
 589                 return EINVAL;
 590         return ((*shmcalls[uap->which])(&uap->a2));
 591 }
 592
 593 void
 594 shmfork(p1, p2)
 595         struct proc *p1, *p2;
 596 {
 597         struct shmmap_state *shmmap_s;
 598         size_t size;
 599         int i;
 600
 601         size = shminfo.shmseg * sizeof(struct shmmap_state);
 602         shmmap_s = malloc(size, M_SHM, M_WAITOK);
 603         bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size);
 604         p2->p_vmspace->vm_shm = (caddr_t)shmmap_s;
 605         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
 606                 if (shmmap_s->shmid != -1)
 607                         shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++;
 608 }
 609
 610 void
 611 shmexit(struct vmspace *vm)
 612 {
 613         struct shmmap_state *base, *shm;
 614         int i;
 615
 616         if ((base = (struct shmmap_state *)vm->vm_shm) != NULL) {
 617                 vm->vm_shm = NULL;
 618                 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) {
 619                         if (shm->shmid != -1)
 620                                 shm_delete_mapping(vm, shm);
 621                 }
 622                 free(base, M_SHM);
 623         }
 624 }
 625
 626 static void
 627 shmrealloc(void)
 628 {
 629         int i;
 630         struct shmid_ds *newsegs;
 631
 632         if (shmalloced >= shminfo.shmmni)
 633                 return;
 634
 635         newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
 636         if (newsegs == NULL)
 637                 return;
 638         for (i = 0; i < shmalloced; i++)
 639                 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
 640         for (; i < shminfo.shmmni; i++) {
 641                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
 642                 shmsegs[i].shm_perm.seq = 0;
 643         }
 644         free(shmsegs, M_SHM);
 645         shmsegs = newsegs;
 646         shmalloced = shminfo.shmmni;
 647 }
 648
 649 static void
 650 shminit(dummy)
 651         void *dummy;
 652 {
 653         int i;
 654
 655         shminfo.shmmax = shminfo.shmall * PAGE_SIZE;
 656         shmalloced = shminfo.shmmni;
 657         shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
 658         if (shmsegs == NULL)
 659                 panic("cannot allocate initial memory for sysvshm");
 660         for (i = 0; i < shmalloced; i++) {
 661                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
 662                 shmsegs[i].shm_perm.seq = 0;
 663         }
 664         shm_last_free = 0;
 665         shm_nused = 0;
 666         shm_committed = 0;
 667 }
 668 SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL);