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 1.21 2008/01/06 16:55:51 swildner 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 <sys/mplock2.h>
  52
  53 #include <vm/vm.h>
  54 #include <vm/vm_param.h>
  55 #include <sys/lock.h>
  56 #include <vm/pmap.h>
  57 #include <vm/vm_object.h>
  58 #include <vm/vm_map.h>
  59 #include <vm/vm_page.h>
  60 #include <vm/vm_pager.h>
  61
  62 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments");
  63
  64 struct oshmctl_args;
  65 static int sys_oshmctl (struct proc *p, struct oshmctl_args *uap);
  66
  67 static int shmget_allocate_segment (struct proc *p, struct shmget_args *uap, int mode);
  68 static int shmget_existing (struct proc *p, struct shmget_args *uap, int mode, int segnum);
  69
  70 /* XXX casting to (sy_call_t *) is bogus, as usual. */
  71 static sy_call_t *shmcalls[] = {
  72         (sy_call_t *)sys_shmat, (sy_call_t *)sys_oshmctl,
  73         (sy_call_t *)sys_shmdt, (sy_call_t *)sys_shmget,
  74         (sy_call_t *)sys_shmctl
  75 };
  76
  77 #define SHMSEG_FREE             0x0200
  78 #define SHMSEG_REMOVED          0x0400
  79 #define SHMSEG_ALLOCATED        0x0800
  80 #define SHMSEG_WANTED           0x1000
  81
  82 static int shm_last_free, shm_nused, shm_committed, shmalloced;
  83 static struct shmid_ds  *shmsegs;
  84
  85 struct shm_handle {
  86         /* vm_offset_t kva; */
  87         vm_object_t shm_object;
  88 };
  89
  90 struct shmmap_state {
  91         vm_offset_t va;
  92         int shmid;
  93 };
  94
  95 static void shm_deallocate_segment (struct shmid_ds *);
  96 static int shm_find_segment_by_key (key_t);
  97 static struct shmid_ds *shm_find_segment_by_shmid (int);
  98 static int shm_delete_mapping (struct vmspace *vm, struct shmmap_state *);
  99 static void shmrealloc (void);
 100 static void shminit (void *);
 101
 102 /*
 103  * Tuneable values
 104  */
 105 #ifndef SHMMAXPGS
 106 #define SHMMAXPGS       8192    /* note: sysv shared memory is swap backed */
 107 #endif
 108 #ifndef SHMMAX
 109 #define SHMMAX  (SHMMAXPGS*PAGE_SIZE)
 110 #endif
 111 #ifndef SHMMIN
 112 #define SHMMIN  1
 113 #endif
 114 #ifndef SHMMNI
 115 #define SHMMNI  192
 116 #endif
 117 #ifndef SHMSEG
 118 #define SHMSEG  128
 119 #endif
 120 #ifndef SHMALL
 121 #define SHMALL  (SHMMAXPGS)
 122 #endif
 123
 124 struct  shminfo shminfo = {
 125         SHMMAX,
 126         SHMMIN,
 127         SHMMNI,
 128         SHMSEG,
 129         SHMALL
 130 };
 131
 132 static int shm_use_phys;
 133
 134 TUNABLE_INT("kern.ipc.shmmin", &shminfo.shmmin);
 135 TUNABLE_INT("kern.ipc.shmmni", &shminfo.shmmni);
 136 TUNABLE_INT("kern.ipc.shmseg", &shminfo.shmseg);
 137 TUNABLE_INT("kern.ipc.shmmaxpgs", &shminfo.shmall);
 138 TUNABLE_INT("kern.ipc.shm_use_phys", &shm_use_phys);
 139
 140 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, "");
 141 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, "");
 142 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0, "");
 143 SYSCTL_INT(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RW, &shminfo.shmseg, 0, "");
 144 SYSCTL_INT(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, "");
 145 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, &shm_use_phys, 0, "");
 146
 147 static int
 148 shm_find_segment_by_key(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(int shmid)
 161 {
 162         int segnum;
 163         struct shmid_ds *shmseg;
 164
 165         segnum = IPCID_TO_IX(shmid);
 166         if (segnum < 0 || segnum >= shmalloced)
 167                 return NULL;
 168         shmseg = &shmsegs[segnum];
 169         if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED))
 170             != SHMSEG_ALLOCATED ||
 171             shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid))
 172                 return NULL;
 173         return shmseg;
 174 }
 175
 176 static void
 177 shm_deallocate_segment(struct shmid_ds *shmseg)
 178 {
 179         struct shm_handle *shm_handle;
 180         size_t size;
 181
 182         shm_handle = shmseg->shm_internal;
 183         vm_object_deallocate(shm_handle->shm_object);
 184         kfree((caddr_t)shm_handle, M_SHM);
 185         shmseg->shm_internal = NULL;
 186         size = round_page(shmseg->shm_segsz);
 187         shm_committed -= btoc(size);
 188         shm_nused--;
 189         shmseg->shm_perm.mode = SHMSEG_FREE;
 190 }
 191
 192 static int
 193 shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s)
 194 {
 195         struct shmid_ds *shmseg;
 196         int segnum, result;
 197         size_t size;
 198
 199         segnum = IPCID_TO_IX(shmmap_s->shmid);
 200         shmseg = &shmsegs[segnum];
 201         size = round_page(shmseg->shm_segsz);
 202         result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size);
 203         if (result != KERN_SUCCESS)
 204                 return EINVAL;
 205         shmmap_s->shmid = -1;
 206         shmseg->shm_dtime = time_second;
 207         if ((--shmseg->shm_nattch <= 0) &&
 208             (shmseg->shm_perm.mode & SHMSEG_REMOVED)) {
 209                 shm_deallocate_segment(shmseg);
 210                 shm_last_free = segnum;
 211         }
 212         return 0;
 213 }
 214
 215 /*
 216  * MPALMOSTSAFE
 217  */
 218 int
 219 sys_shmdt(struct shmdt_args *uap)
 220 {
 221         struct thread *td = curthread;
 222         struct proc *p = td->td_proc;
 223         struct shmmap_state *shmmap_s;
 224         int i;
 225         int error;
 226
 227         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
 228                 return (ENOSYS);
 229
 230         get_mplock();
 231         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
 232         if (shmmap_s == NULL) {
 233                 error = EINVAL;
 234                 goto done;
 235         }
 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         }
 241         if (i == shminfo.shmseg)
 242                 error = EINVAL;
 243         else
 244                 error = shm_delete_mapping(p->p_vmspace, shmmap_s);
 245 done:
 246         rel_mplock();
 247         return (error);
 248 }
 249
 250 /*
 251  * MPALMOSTSAFE
 252  */
 253 int
 254 sys_shmat(struct shmat_args *uap)
 255 {
 256         struct thread *td = curthread;
 257         struct proc *p = td->td_proc;
 258         int error, i, flags;
 259         struct shmid_ds *shmseg;
 260         struct shmmap_state *shmmap_s = NULL;
 261         struct shm_handle *shm_handle;
 262         vm_offset_t attach_va;
 263         vm_prot_t prot;
 264         vm_size_t size;
 265         int rv;
 266
 267         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
 268                 return (ENOSYS);
 269
 270         get_mplock();
 271 again:
 272         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
 273         if (shmmap_s == NULL) {
 274                 size = shminfo.shmseg * sizeof(struct shmmap_state);
 275                 shmmap_s = kmalloc(size, M_SHM, M_WAITOK);
 276                 for (i = 0; i < shminfo.shmseg; i++)
 277                         shmmap_s[i].shmid = -1;
 278                 if (p->p_vmspace->vm_shm != NULL) {
 279                         kfree(shmmap_s, M_SHM);
 280                         goto again;
 281                 }
 282                 p->p_vmspace->vm_shm = (caddr_t)shmmap_s;
 283         }
 284         shmseg = shm_find_segment_by_shmid(uap->shmid);
 285         if (shmseg == NULL) {
 286                 error = EINVAL;
 287                 goto done;
 288         }
 289         error = ipcperm(p, &shmseg->shm_perm,
 290                         (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
 291         if (error)
 292                 goto done;
 293         for (i = 0; i < shminfo.shmseg; i++) {
 294                 if (shmmap_s->shmid == -1)
 295                         break;
 296                 shmmap_s++;
 297         }
 298         if (i >= shminfo.shmseg) {
 299                 error = EMFILE;
 300                 goto done;
 301         }
 302         size = round_page(shmseg->shm_segsz);
 303 #ifdef VM_PROT_READ_IS_EXEC
 304         prot = VM_PROT_READ | VM_PROT_EXECUTE;
 305 #else
 306         prot = VM_PROT_READ;
 307 #endif
 308         if ((uap->shmflg & SHM_RDONLY) == 0)
 309                 prot |= VM_PROT_WRITE;
 310         flags = MAP_ANON | MAP_SHARED;
 311         if (uap->shmaddr) {
 312                 flags |= MAP_FIXED;
 313                 if (uap->shmflg & SHM_RND) {
 314                         attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1);
 315                 } else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0) {
 316                         attach_va = (vm_offset_t)uap->shmaddr;
 317                 } else {
 318                         error = EINVAL;
 319                         goto done;
 320                 }
 321         } else {
 322                 /*
 323                  * This is just a hint to vm_map_find() about where to put it.
 324                  */
 325                 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr + maxtsiz + maxdsiz);
 326         }
 327
 328         shm_handle = shmseg->shm_internal;
 329         vm_object_reference(shm_handle->shm_object);
 330         rv = vm_map_find(&p->p_vmspace->vm_map,
 331                          shm_handle->shm_object, 0,
 332                          &attach_va,
 333                          size, PAGE_SIZE,
 334                          ((flags & MAP_FIXED) ? 0 : 1),
 335                          VM_MAPTYPE_NORMAL,
 336                          prot, prot,
 337                          0);
 338         if (rv != KERN_SUCCESS) {
 339                 vm_object_deallocate(shm_handle->shm_object);
 340                 error = ENOMEM;
 341                 goto done;
 342         }
 343         vm_map_inherit(&p->p_vmspace->vm_map,
 344                        attach_va, attach_va + size, VM_INHERIT_SHARE);
 345
 346         KKASSERT(shmmap_s->shmid == -1);
 347         shmmap_s->va = attach_va;
 348         shmmap_s->shmid = uap->shmid;
 349         shmseg->shm_lpid = p->p_pid;
 350         shmseg->shm_atime = time_second;
 351         shmseg->shm_nattch++;
 352         uap->sysmsg_result = attach_va;
 353         error = 0;
 354 done:
 355         rel_mplock();
 356         return error;
 357 }
 358
 359 struct oshmid_ds {
 360         struct  ipc_perm shm_perm;      /* operation perms */
 361         int     shm_segsz;              /* size of segment (bytes) */
 362         ushort  shm_cpid;               /* pid, creator */
 363         ushort  shm_lpid;               /* pid, last operation */
 364         short   shm_nattch;             /* no. of current attaches */
 365         time_t  shm_atime;              /* last attach time */
 366         time_t  shm_dtime;              /* last detach time */
 367         time_t  shm_ctime;              /* last change time */
 368         void    *shm_handle;            /* internal handle for shm segment */
 369 };
 370
 371 struct oshmctl_args {
 372         struct sysmsg sysmsg;
 373         int shmid;
 374         int cmd;
 375         struct oshmid_ds *ubuf;
 376 };
 377
 378 /*
 379  * MPALMOSTSAFE
 380  */
 381 static int
 382 sys_oshmctl(struct proc *p, struct oshmctl_args *uap)
 383 {
 384 #ifdef COMPAT_43
 385         struct thread *td = curthread;
 386         struct shmid_ds *shmseg;
 387         struct oshmid_ds outbuf;
 388         int error;
 389
 390         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
 391                 return (ENOSYS);
 392
 393         get_mplock();
 394         shmseg = shm_find_segment_by_shmid(uap->shmid);
 395         if (shmseg == NULL) {
 396                 error = EINVAL;
 397                 goto done;
 398         }
 399
 400         switch (uap->cmd) {
 401         case IPC_STAT:
 402                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
 403                 if (error)
 404                         break;
 405                 outbuf.shm_perm = shmseg->shm_perm;
 406                 outbuf.shm_segsz = shmseg->shm_segsz;
 407                 outbuf.shm_cpid = shmseg->shm_cpid;
 408                 outbuf.shm_lpid = shmseg->shm_lpid;
 409                 outbuf.shm_nattch = shmseg->shm_nattch;
 410                 outbuf.shm_atime = shmseg->shm_atime;
 411                 outbuf.shm_dtime = shmseg->shm_dtime;
 412                 outbuf.shm_ctime = shmseg->shm_ctime;
 413                 outbuf.shm_handle = shmseg->shm_internal;
 414                 error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf));
 415                 break;
 416         default:
 417                 /* XXX casting to (sy_call_t *) is bogus, as usual. */
 418                 error = sys_shmctl((struct shmctl_args *)uap);
 419         }
 420 done:
 421         rel_mplock();
 422         return error;
 423 #else
 424         return EINVAL;
 425 #endif
 426 }
 427
 428 /*
 429  * MPALMOSTSAFE
 430  */
 431 int
 432 sys_shmctl(struct shmctl_args *uap)
 433 {
 434         struct thread *td = curthread;
 435         struct proc *p = td->td_proc;
 436         int error;
 437         struct shmid_ds inbuf;
 438         struct shmid_ds *shmseg;
 439
 440         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
 441                 return (ENOSYS);
 442
 443         get_mplock();
 444         shmseg = shm_find_segment_by_shmid(uap->shmid);
 445         if (shmseg == NULL) {
 446                 error = EINVAL;
 447                 goto done;
 448         }
 449
 450         switch (uap->cmd) {
 451         case IPC_STAT:
 452                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
 453                 if (error == 0)
 454                         error = copyout(shmseg, uap->buf, sizeof(inbuf));
 455                 break;
 456         case IPC_SET:
 457                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
 458                 if (error == 0)
 459                         error = copyin(uap->buf, &inbuf, sizeof(inbuf));
 460                 if (error == 0) {
 461                         shmseg->shm_perm.uid = inbuf.shm_perm.uid;
 462                         shmseg->shm_perm.gid = inbuf.shm_perm.gid;
 463                         shmseg->shm_perm.mode =
 464                             (shmseg->shm_perm.mode & ~ACCESSPERMS) |
 465                             (inbuf.shm_perm.mode & ACCESSPERMS);
 466                         shmseg->shm_ctime = time_second;
 467                 }
 468                 break;
 469         case IPC_RMID:
 470                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
 471                 if (error == 0) {
 472                         shmseg->shm_perm.key = IPC_PRIVATE;
 473                         shmseg->shm_perm.mode |= SHMSEG_REMOVED;
 474                         if (shmseg->shm_nattch <= 0) {
 475                                 shm_deallocate_segment(shmseg);
 476                                 shm_last_free = IPCID_TO_IX(uap->shmid);
 477                         }
 478                 }
 479                 break;
 480 #if 0
 481         case SHM_LOCK:
 482         case SHM_UNLOCK:
 483 #endif
 484         default:
 485                 error = EINVAL;
 486                 break;
 487         }
 488 done:
 489         rel_mplock();
 490         return error;
 491 }
 492
 493 static int
 494 shmget_existing(struct proc *p, struct shmget_args *uap, int mode, int segnum)
 495 {
 496         struct shmid_ds *shmseg;
 497         int error;
 498
 499         shmseg = &shmsegs[segnum];
 500         if (shmseg->shm_perm.mode & SHMSEG_REMOVED) {
 501                 /*
 502                  * This segment is in the process of being allocated.  Wait
 503                  * until it's done, and look the key up again (in case the
 504                  * allocation failed or it was freed).
 505                  */
 506                 shmseg->shm_perm.mode |= SHMSEG_WANTED;
 507                 error = tsleep((caddr_t)shmseg, PCATCH, "shmget", 0);
 508                 if (error)
 509                         return error;
 510                 return EAGAIN;
 511         }
 512         if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
 513                 return EEXIST;
 514         error = ipcperm(p, &shmseg->shm_perm, mode);
 515         if (error)
 516                 return error;
 517         if (uap->size && uap->size > shmseg->shm_segsz)
 518                 return EINVAL;
 519         uap->sysmsg_result = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
 520         return 0;
 521 }
 522
 523 static int
 524 shmget_allocate_segment(struct proc *p, struct shmget_args *uap, int mode)
 525 {
 526         int i, segnum, shmid, size;
 527         struct ucred *cred = p->p_ucred;
 528         struct shmid_ds *shmseg;
 529         struct shm_handle *shm_handle;
 530
 531         if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
 532                 return EINVAL;
 533         if (shm_nused >= shminfo.shmmni) /* any shmids left? */
 534                 return ENOSPC;
 535         size = round_page(uap->size);
 536         if (shm_committed + btoc(size) > shminfo.shmall)
 537                 return ENOMEM;
 538         if (shm_last_free < 0) {
 539                 shmrealloc();   /* maybe expand the shmsegs[] array */
 540                 for (i = 0; i < shmalloced; i++)
 541                         if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
 542                                 break;
 543                 if (i == shmalloced)
 544                         return ENOSPC;
 545                 segnum = i;
 546         } else  {
 547                 segnum = shm_last_free;
 548                 shm_last_free = -1;
 549         }
 550         shmseg = &shmsegs[segnum];
 551         /*
 552          * In case we sleep in malloc(), mark the segment present but deleted
 553          * so that noone else tries to create the same key.
 554          */
 555         shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
 556         shmseg->shm_perm.key = uap->key;
 557         shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff;
 558         shm_handle = kmalloc(sizeof(struct shm_handle), M_SHM, M_WAITOK);
 559         shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
 560
 561         /*
 562          * We make sure that we have allocated a pager before we need
 563          * to.
 564          */
 565         if (shm_use_phys) {
 566                 shm_handle->shm_object =
 567                    phys_pager_alloc(NULL, size, VM_PROT_DEFAULT, 0);
 568         } else {
 569                 shm_handle->shm_object =
 570                    swap_pager_alloc(NULL, size, VM_PROT_DEFAULT, 0);
 571         }
 572         vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING);
 573         vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT);
 574
 575         shmseg->shm_internal = shm_handle;
 576         shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid;
 577         shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid;
 578         shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
 579             (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
 580         shmseg->shm_segsz = uap->size;
 581         shmseg->shm_cpid = p->p_pid;
 582         shmseg->shm_lpid = shmseg->shm_nattch = 0;
 583         shmseg->shm_atime = shmseg->shm_dtime = 0;
 584         shmseg->shm_ctime = time_second;
 585         shm_committed += btoc(size);
 586         shm_nused++;
 587         if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
 588                 /*
 589                  * Somebody else wanted this key while we were asleep.  Wake
 590                  * them up now.
 591                  */
 592                 shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
 593                 wakeup((caddr_t)shmseg);
 594         }
 595         uap->sysmsg_result = shmid;
 596         return 0;
 597 }
 598
 599 /*
 600  * MPALMOSTSAFE
 601  */
 602 int
 603 sys_shmget(struct shmget_args *uap)
 604 {
 605         struct thread *td = curthread;
 606         struct proc *p = td->td_proc;
 607         int segnum, mode, error;
 608
 609         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
 610                 return (ENOSYS);
 611
 612         mode = uap->shmflg & ACCESSPERMS;
 613         get_mplock();
 614
 615         if (uap->key != IPC_PRIVATE) {
 616         again:
 617                 segnum = shm_find_segment_by_key(uap->key);
 618                 if (segnum >= 0) {
 619                         error = shmget_existing(p, uap, mode, segnum);
 620                         if (error == EAGAIN)
 621                                 goto again;
 622                         goto done;
 623                 }
 624                 if ((uap->shmflg & IPC_CREAT) == 0) {
 625                         error = ENOENT;
 626                         goto done;
 627                 }
 628         }
 629         error = shmget_allocate_segment(p, uap, mode);
 630 done:
 631         rel_mplock();
 632         return (error);
 633 }
 634
 635 /*
 636  * shmsys_args(int which, int a2, ...) (VARARGS)
 637  *
 638  * MPALMOSTSAFE
 639  */
 640 int
 641 sys_shmsys(struct shmsys_args *uap)
 642 {
 643         struct thread *td = curthread;
 644         unsigned int which = (unsigned int)uap->which;
 645         int error;
 646
 647         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
 648                 return (ENOSYS);
 649
 650         if (which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
 651                 return EINVAL;
 652         get_mplock();
 653         bcopy(&uap->a2, &uap->which,
 654                 sizeof(struct shmsys_args) - offsetof(struct shmsys_args, a2));
 655         error = ((*shmcalls[which])(uap));
 656         rel_mplock();
 657
 658         return(error);
 659 }
 660
 661 void
 662 shmfork(struct proc *p1, struct proc *p2)
 663 {
 664         struct shmmap_state *shmmap_s;
 665         size_t size;
 666         int i;
 667
 668         size = shminfo.shmseg * sizeof(struct shmmap_state);
 669         shmmap_s = kmalloc(size, M_SHM, M_WAITOK);
 670         bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size);
 671         p2->p_vmspace->vm_shm = (caddr_t)shmmap_s;
 672         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
 673                 if (shmmap_s->shmid != -1)
 674                         shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++;
 675 }
 676
 677 void
 678 shmexit(struct vmspace *vm)
 679 {
 680         struct shmmap_state *base, *shm;
 681         int i;
 682
 683         if ((base = (struct shmmap_state *)vm->vm_shm) != NULL) {
 684                 vm->vm_shm = NULL;
 685                 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) {
 686                         if (shm->shmid != -1)
 687                                 shm_delete_mapping(vm, shm);
 688                 }
 689                 kfree(base, M_SHM);
 690         }
 691 }
 692
 693 static void
 694 shmrealloc(void)
 695 {
 696         int i;
 697         struct shmid_ds *newsegs;
 698
 699         if (shmalloced >= shminfo.shmmni)
 700                 return;
 701
 702         newsegs = kmalloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
 703         for (i = 0; i < shmalloced; i++)
 704                 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
 705         for (; i < shminfo.shmmni; i++) {
 706                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
 707                 shmsegs[i].shm_perm.seq = 0;
 708         }
 709         kfree(shmsegs, M_SHM);
 710         shmsegs = newsegs;
 711         shmalloced = shminfo.shmmni;
 712 }
 713
 714 static void
 715 shminit(void *dummy)
 716 {
 717         int i;
 718
 719         shminfo.shmmax = shminfo.shmall * PAGE_SIZE;
 720         shmalloced = shminfo.shmmni;
 721         shmsegs = kmalloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
 722         for (i = 0; i < shmalloced; i++) {
 723                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
 724                 shmsegs[i].shm_perm.seq = 0;
 725         }
 726         shm_last_free = 0;
 727         shm_nused = 0;
 728         shm_committed = 0;
 729 }
 730 SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL);