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_committed, shmalloced;
  83 int shm_nused;
  84 static struct shmid_ds  *shmsegs;
  85
  86 struct shm_handle {
  87         /* vm_offset_t kva; */
  88         vm_object_t shm_object;
  89 };
  90
  91 struct shmmap_state {
  92         vm_offset_t va;
  93         int shmid;
  94 };
  95
  96 static void shm_deallocate_segment (struct shmid_ds *);
  97 static int shm_find_segment_by_key (key_t);
  98 static struct shmid_ds *shm_find_segment_by_shmid (int);
  99 static int shm_delete_mapping (struct vmspace *vm, struct shmmap_state *);
 100 static void shmrealloc (void);
 101 static void shminit (void *);
 102
 103 /*
 104  * Tuneable values
 105  */
 106 #ifndef SHMMAXPGS
 107 #define SHMMAXPGS       8192    /* note: sysv shared memory is swap backed */
 108 #endif
 109 #ifndef SHMMAX
 110 #define SHMMAX  (SHMMAXPGS*PAGE_SIZE)
 111 #endif
 112 #ifndef SHMMIN
 113 #define SHMMIN  1
 114 #endif
 115 #ifndef SHMMNI
 116 #define SHMMNI  192
 117 #endif
 118 #ifndef SHMSEG
 119 #define SHMSEG  128
 120 #endif
 121 #ifndef SHMALL
 122 #define SHMALL  (SHMMAXPGS)
 123 #endif
 124
 125 struct  shminfo shminfo = {
 126         SHMMAX,
 127         SHMMIN,
 128         SHMMNI,
 129         SHMSEG,
 130         SHMALL
 131 };
 132
 133 static int shm_use_phys;
 134
 135 TUNABLE_INT("kern.ipc.shmmin", &shminfo.shmmin);
 136 TUNABLE_INT("kern.ipc.shmmni", &shminfo.shmmni);
 137 TUNABLE_INT("kern.ipc.shmseg", &shminfo.shmseg);
 138 TUNABLE_INT("kern.ipc.shmmaxpgs", &shminfo.shmall);
 139 TUNABLE_INT("kern.ipc.shm_use_phys", &shm_use_phys);
 140
 141 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0,
 142     "Max shared memory segment size");
 143 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0,
 144     "Min shared memory segment size");
 145 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0,
 146     "Max number of shared memory identifiers");
 147 SYSCTL_INT(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RW, &shminfo.shmseg, 0,
 148     "Max shared memory segments per process");
 149 SYSCTL_INT(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0,
 150     "Max pages of shared memory");
 151 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, &shm_use_phys, 0,
 152     "Use phys pager allocation instead of swap pager allocation");
 153
 154 static int
 155 shm_find_segment_by_key(key_t key)
 156 {
 157         int i;
 158
 159         for (i = 0; i < shmalloced; i++)
 160                 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) &&
 161                     shmsegs[i].shm_perm.key == key)
 162                         return i;
 163         return -1;
 164 }
 165
 166 static struct shmid_ds *
 167 shm_find_segment_by_shmid(int shmid)
 168 {
 169         int segnum;
 170         struct shmid_ds *shmseg;
 171
 172         segnum = IPCID_TO_IX(shmid);
 173         if (segnum < 0 || segnum >= shmalloced)
 174                 return NULL;
 175         shmseg = &shmsegs[segnum];
 176         if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED))
 177             != SHMSEG_ALLOCATED ||
 178             shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid))
 179                 return NULL;
 180         return shmseg;
 181 }
 182
 183 static void
 184 shm_deallocate_segment(struct shmid_ds *shmseg)
 185 {
 186         struct shm_handle *shm_handle;
 187         size_t size;
 188
 189         shm_handle = shmseg->shm_internal;
 190         vm_object_deallocate(shm_handle->shm_object);
 191         kfree((caddr_t)shm_handle, M_SHM);
 192         shmseg->shm_internal = NULL;
 193         size = round_page(shmseg->shm_segsz);
 194         shm_committed -= btoc(size);
 195         shm_nused--;
 196         shmseg->shm_perm.mode = SHMSEG_FREE;
 197 }
 198
 199 static int
 200 shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s)
 201 {
 202         struct shmid_ds *shmseg;
 203         int segnum, result;
 204         size_t size;
 205
 206         segnum = IPCID_TO_IX(shmmap_s->shmid);
 207         shmseg = &shmsegs[segnum];
 208         size = round_page(shmseg->shm_segsz);
 209         result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size);
 210         if (result != KERN_SUCCESS)
 211                 return EINVAL;
 212         shmmap_s->shmid = -1;
 213         shmseg->shm_dtime = time_second;
 214         if ((--shmseg->shm_nattch <= 0) &&
 215             (shmseg->shm_perm.mode & SHMSEG_REMOVED)) {
 216                 shm_deallocate_segment(shmseg);
 217                 shm_last_free = segnum;
 218         }
 219         return 0;
 220 }
 221
 222 /*
 223  * MPALMOSTSAFE
 224  */
 225 int
 226 sys_shmdt(struct shmdt_args *uap)
 227 {
 228         struct thread *td = curthread;
 229         struct proc *p = td->td_proc;
 230         struct shmmap_state *shmmap_s;
 231         int i;
 232         int error;
 233
 234         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
 235                 return (ENOSYS);
 236
 237         get_mplock();
 238         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
 239         if (shmmap_s == NULL) {
 240                 error = EINVAL;
 241                 goto done;
 242         }
 243         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) {
 244                 if (shmmap_s->shmid != -1 &&
 245                     shmmap_s->va == (vm_offset_t)uap->shmaddr)
 246                         break;
 247         }
 248         if (i == shminfo.shmseg)
 249                 error = EINVAL;
 250         else
 251                 error = shm_delete_mapping(p->p_vmspace, shmmap_s);
 252 done:
 253         rel_mplock();
 254         return (error);
 255 }
 256
 257 /*
 258  * MPALMOSTSAFE
 259  */
 260 int
 261 sys_shmat(struct shmat_args *uap)
 262 {
 263         struct thread *td = curthread;
 264         struct proc *p = td->td_proc;
 265         int error, i, flags;
 266         struct shmid_ds *shmseg;
 267         struct shmmap_state *shmmap_s = NULL;
 268         struct shm_handle *shm_handle;
 269         vm_offset_t attach_va;
 270         vm_prot_t prot;
 271         vm_size_t size;
 272         int rv;
 273
 274         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
 275                 return (ENOSYS);
 276
 277         get_mplock();
 278 again:
 279         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
 280         if (shmmap_s == NULL) {
 281                 size = shminfo.shmseg * sizeof(struct shmmap_state);
 282                 shmmap_s = kmalloc(size, M_SHM, M_WAITOK);
 283                 for (i = 0; i < shminfo.shmseg; i++)
 284                         shmmap_s[i].shmid = -1;
 285                 if (p->p_vmspace->vm_shm != NULL) {
 286                         kfree(shmmap_s, M_SHM);
 287                         goto again;
 288                 }
 289                 p->p_vmspace->vm_shm = (caddr_t)shmmap_s;
 290         }
 291         shmseg = shm_find_segment_by_shmid(uap->shmid);
 292         if (shmseg == NULL) {
 293                 error = EINVAL;
 294                 goto done;
 295         }
 296         error = ipcperm(p, &shmseg->shm_perm,
 297                         (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
 298         if (error)
 299                 goto done;
 300         for (i = 0; i < shminfo.shmseg; i++) {
 301                 if (shmmap_s->shmid == -1)
 302                         break;
 303                 shmmap_s++;
 304         }
 305         if (i >= shminfo.shmseg) {
 306                 error = EMFILE;
 307                 goto done;
 308         }
 309         size = round_page(shmseg->shm_segsz);
 310 #ifdef VM_PROT_READ_IS_EXEC
 311         prot = VM_PROT_READ | VM_PROT_EXECUTE;
 312 #else
 313         prot = VM_PROT_READ;
 314 #endif
 315         if ((uap->shmflg & SHM_RDONLY) == 0)
 316                 prot |= VM_PROT_WRITE;
 317         flags = MAP_ANON | MAP_SHARED;
 318         if (uap->shmaddr) {
 319                 flags |= MAP_FIXED;
 320                 if (uap->shmflg & SHM_RND) {
 321                         attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1);
 322                 } else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0) {
 323                         attach_va = (vm_offset_t)uap->shmaddr;
 324                 } else {
 325                         error = EINVAL;
 326                         goto done;
 327                 }
 328         } else {
 329                 /*
 330                  * This is just a hint to vm_map_find() about where to put it.
 331                  */
 332                 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr + maxtsiz + maxdsiz);
 333         }
 334
 335         shm_handle = shmseg->shm_internal;
 336         vm_object_reference(shm_handle->shm_object);
 337         rv = vm_map_find(&p->p_vmspace->vm_map,
 338                          shm_handle->shm_object, 0,
 339                          &attach_va,
 340                          size, PAGE_SIZE,
 341                          ((flags & MAP_FIXED) ? 0 : 1),
 342                          VM_MAPTYPE_NORMAL,
 343                          prot, prot,
 344                          0);
 345         if (rv != KERN_SUCCESS) {
 346                 vm_object_deallocate(shm_handle->shm_object);
 347                 error = ENOMEM;
 348                 goto done;
 349         }
 350         vm_map_inherit(&p->p_vmspace->vm_map,
 351                        attach_va, attach_va + size, VM_INHERIT_SHARE);
 352
 353         KKASSERT(shmmap_s->shmid == -1);
 354         shmmap_s->va = attach_va;
 355         shmmap_s->shmid = uap->shmid;
 356         shmseg->shm_lpid = p->p_pid;
 357         shmseg->shm_atime = time_second;
 358         shmseg->shm_nattch++;
 359         uap->sysmsg_resultp = (void *)attach_va;
 360         error = 0;
 361 done:
 362         rel_mplock();
 363         return error;
 364 }
 365
 366 struct oshmid_ds {
 367         struct  ipc_perm shm_perm;      /* operation perms */
 368         int     shm_segsz;              /* size of segment (bytes) */
 369         ushort  shm_cpid;               /* pid, creator */
 370         ushort  shm_lpid;               /* pid, last operation */
 371         short   shm_nattch;             /* no. of current attaches */
 372         time_t  shm_atime;              /* last attach time */
 373         time_t  shm_dtime;              /* last detach time */
 374         time_t  shm_ctime;              /* last change time */
 375         void    *shm_handle;            /* internal handle for shm segment */
 376 };
 377
 378 struct oshmctl_args {
 379         struct sysmsg sysmsg;
 380         int shmid;
 381         int cmd;
 382         struct oshmid_ds *ubuf;
 383 };
 384
 385 /*
 386  * MPALMOSTSAFE
 387  */
 388 static int
 389 sys_oshmctl(struct proc *p, struct oshmctl_args *uap)
 390 {
 391 #ifdef COMPAT_43
 392         struct thread *td = curthread;
 393         struct shmid_ds *shmseg;
 394         struct oshmid_ds outbuf;
 395         int error;
 396
 397         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
 398                 return (ENOSYS);
 399
 400         get_mplock();
 401         shmseg = shm_find_segment_by_shmid(uap->shmid);
 402         if (shmseg == NULL) {
 403                 error = EINVAL;
 404                 goto done;
 405         }
 406
 407         switch (uap->cmd) {
 408         case IPC_STAT:
 409                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
 410                 if (error)
 411                         break;
 412                 outbuf.shm_perm = shmseg->shm_perm;
 413                 outbuf.shm_segsz = shmseg->shm_segsz;
 414                 outbuf.shm_cpid = shmseg->shm_cpid;
 415                 outbuf.shm_lpid = shmseg->shm_lpid;
 416                 outbuf.shm_nattch = shmseg->shm_nattch;
 417                 outbuf.shm_atime = shmseg->shm_atime;
 418                 outbuf.shm_dtime = shmseg->shm_dtime;
 419                 outbuf.shm_ctime = shmseg->shm_ctime;
 420                 outbuf.shm_handle = shmseg->shm_internal;
 421                 error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf));
 422                 break;
 423         default:
 424                 /* XXX casting to (sy_call_t *) is bogus, as usual. */
 425                 error = sys_shmctl((struct shmctl_args *)uap);
 426         }
 427 done:
 428         rel_mplock();
 429         return error;
 430 #else
 431         return EINVAL;
 432 #endif
 433 }
 434
 435 /*
 436  * MPALMOSTSAFE
 437  */
 438 int
 439 sys_shmctl(struct shmctl_args *uap)
 440 {
 441         struct thread *td = curthread;
 442         struct proc *p = td->td_proc;
 443         int error;
 444         struct shmid_ds inbuf;
 445         struct shmid_ds *shmseg;
 446
 447         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
 448                 return (ENOSYS);
 449
 450         get_mplock();
 451         shmseg = shm_find_segment_by_shmid(uap->shmid);
 452         if (shmseg == NULL) {
 453                 error = EINVAL;
 454                 goto done;
 455         }
 456
 457         switch (uap->cmd) {
 458         case IPC_STAT:
 459                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
 460                 if (error == 0)
 461                         error = copyout(shmseg, uap->buf, sizeof(inbuf));
 462                 break;
 463         case IPC_SET:
 464                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
 465                 if (error == 0)
 466                         error = copyin(uap->buf, &inbuf, sizeof(inbuf));
 467                 if (error == 0) {
 468                         shmseg->shm_perm.uid = inbuf.shm_perm.uid;
 469                         shmseg->shm_perm.gid = inbuf.shm_perm.gid;
 470                         shmseg->shm_perm.mode =
 471                             (shmseg->shm_perm.mode & ~ACCESSPERMS) |
 472                             (inbuf.shm_perm.mode & ACCESSPERMS);
 473                         shmseg->shm_ctime = time_second;
 474                 }
 475                 break;
 476         case IPC_RMID:
 477                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
 478                 if (error == 0) {
 479                         shmseg->shm_perm.key = IPC_PRIVATE;
 480                         shmseg->shm_perm.mode |= SHMSEG_REMOVED;
 481                         if (shmseg->shm_nattch <= 0) {
 482                                 shm_deallocate_segment(shmseg);
 483                                 shm_last_free = IPCID_TO_IX(uap->shmid);
 484                         }
 485                 }
 486                 break;
 487 #if 0
 488         case SHM_LOCK:
 489         case SHM_UNLOCK:
 490 #endif
 491         default:
 492                 error = EINVAL;
 493                 break;
 494         }
 495 done:
 496         rel_mplock();
 497         return error;
 498 }
 499
 500 static int
 501 shmget_existing(struct proc *p, struct shmget_args *uap, int mode, int segnum)
 502 {
 503         struct shmid_ds *shmseg;
 504         int error;
 505
 506         shmseg = &shmsegs[segnum];
 507         if (shmseg->shm_perm.mode & SHMSEG_REMOVED) {
 508                 /*
 509                  * This segment is in the process of being allocated.  Wait
 510                  * until it's done, and look the key up again (in case the
 511                  * allocation failed or it was freed).
 512                  */
 513                 shmseg->shm_perm.mode |= SHMSEG_WANTED;
 514                 error = tsleep((caddr_t)shmseg, PCATCH, "shmget", 0);
 515                 if (error)
 516                         return error;
 517                 return EAGAIN;
 518         }
 519         if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
 520                 return EEXIST;
 521         error = ipcperm(p, &shmseg->shm_perm, mode);
 522         if (error)
 523                 return error;
 524         if (uap->size && uap->size > shmseg->shm_segsz)
 525                 return EINVAL;
 526         uap->sysmsg_result = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
 527         return 0;
 528 }
 529
 530 static int
 531 shmget_allocate_segment(struct proc *p, struct shmget_args *uap, int mode)
 532 {
 533         int i, segnum, shmid, size;
 534         struct ucred *cred = p->p_ucred;
 535         struct shmid_ds *shmseg;
 536         struct shm_handle *shm_handle;
 537
 538         if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
 539                 return EINVAL;
 540         if (shm_nused >= shminfo.shmmni) /* any shmids left? */
 541                 return ENOSPC;
 542         size = round_page(uap->size);
 543         if (shm_committed + btoc(size) > shminfo.shmall)
 544                 return ENOMEM;
 545         if (shm_last_free < 0) {
 546                 shmrealloc();   /* maybe expand the shmsegs[] array */
 547                 for (i = 0; i < shmalloced; i++)
 548                         if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
 549                                 break;
 550                 if (i == shmalloced)
 551                         return ENOSPC;
 552                 segnum = i;
 553         } else  {
 554                 segnum = shm_last_free;
 555                 shm_last_free = -1;
 556         }
 557         shmseg = &shmsegs[segnum];
 558         /*
 559          * In case we sleep in malloc(), mark the segment present but deleted
 560          * so that noone else tries to create the same key.
 561          */
 562         shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
 563         shmseg->shm_perm.key = uap->key;
 564         shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff;
 565         shm_handle = kmalloc(sizeof(struct shm_handle), M_SHM, M_WAITOK);
 566         shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
 567
 568         /*
 569          * We make sure that we have allocated a pager before we need
 570          * to.
 571          */
 572         if (shm_use_phys) {
 573                 shm_handle->shm_object =
 574                    phys_pager_alloc(NULL, size, VM_PROT_DEFAULT, 0);
 575         } else {
 576                 shm_handle->shm_object =
 577                    swap_pager_alloc(NULL, size, VM_PROT_DEFAULT, 0);
 578         }
 579         vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING);
 580         vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT);
 581
 582         shmseg->shm_internal = shm_handle;
 583         shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid;
 584         shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid;
 585         shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
 586             (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
 587         shmseg->shm_segsz = uap->size;
 588         shmseg->shm_cpid = p->p_pid;
 589         shmseg->shm_lpid = shmseg->shm_nattch = 0;
 590         shmseg->shm_atime = shmseg->shm_dtime = 0;
 591         shmseg->shm_ctime = time_second;
 592         shm_committed += btoc(size);
 593         shm_nused++;
 594         if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
 595                 /*
 596                  * Somebody else wanted this key while we were asleep.  Wake
 597                  * them up now.
 598                  */
 599                 shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
 600                 wakeup((caddr_t)shmseg);
 601         }
 602         uap->sysmsg_result = shmid;
 603         return 0;
 604 }
 605
 606 /*
 607  * MPALMOSTSAFE
 608  */
 609 int
 610 sys_shmget(struct shmget_args *uap)
 611 {
 612         struct thread *td = curthread;
 613         struct proc *p = td->td_proc;
 614         int segnum, mode, error;
 615
 616         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
 617                 return (ENOSYS);
 618
 619         mode = uap->shmflg & ACCESSPERMS;
 620         get_mplock();
 621
 622         if (uap->key != IPC_PRIVATE) {
 623         again:
 624                 segnum = shm_find_segment_by_key(uap->key);
 625                 if (segnum >= 0) {
 626                         error = shmget_existing(p, uap, mode, segnum);
 627                         if (error == EAGAIN)
 628                                 goto again;
 629                         goto done;
 630                 }
 631                 if ((uap->shmflg & IPC_CREAT) == 0) {
 632                         error = ENOENT;
 633                         goto done;
 634                 }
 635         }
 636         error = shmget_allocate_segment(p, uap, mode);
 637 done:
 638         rel_mplock();
 639         return (error);
 640 }
 641
 642 /*
 643  * shmsys_args(int which, int a2, ...) (VARARGS)
 644  *
 645  * MPALMOSTSAFE
 646  */
 647 int
 648 sys_shmsys(struct shmsys_args *uap)
 649 {
 650         struct thread *td = curthread;
 651         unsigned int which = (unsigned int)uap->which;
 652         int error;
 653
 654         if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL)
 655                 return (ENOSYS);
 656
 657         if (which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
 658                 return EINVAL;
 659         get_mplock();
 660         bcopy(&uap->a2, &uap->which,
 661                 sizeof(struct shmsys_args) - offsetof(struct shmsys_args, a2));
 662         error = ((*shmcalls[which])(uap));
 663         rel_mplock();
 664
 665         return(error);
 666 }
 667
 668 void
 669 shmfork(struct proc *p1, struct proc *p2)
 670 {
 671         struct shmmap_state *shmmap_s;
 672         size_t size;
 673         int i;
 674
 675         size = shminfo.shmseg * sizeof(struct shmmap_state);
 676         shmmap_s = kmalloc(size, M_SHM, M_WAITOK);
 677         bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size);
 678         p2->p_vmspace->vm_shm = (caddr_t)shmmap_s;
 679         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
 680                 if (shmmap_s->shmid != -1)
 681                         shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++;
 682 }
 683
 684 void
 685 shmexit(struct vmspace *vm)
 686 {
 687         struct shmmap_state *base, *shm;
 688         int i;
 689
 690         if ((base = (struct shmmap_state *)vm->vm_shm) != NULL) {
 691                 vm->vm_shm = NULL;
 692                 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) {
 693                         if (shm->shmid != -1)
 694                                 shm_delete_mapping(vm, shm);
 695                 }
 696                 kfree(base, M_SHM);
 697         }
 698 }
 699
 700 static void
 701 shmrealloc(void)
 702 {
 703         int i;
 704         struct shmid_ds *newsegs;
 705
 706         if (shmalloced >= shminfo.shmmni)
 707                 return;
 708
 709         newsegs = kmalloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
 710         for (i = 0; i < shmalloced; i++)
 711                 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
 712         for (; i < shminfo.shmmni; i++) {
 713                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
 714                 shmsegs[i].shm_perm.seq = 0;
 715         }
 716         kfree(shmsegs, M_SHM);
 717         shmsegs = newsegs;
 718         shmalloced = shminfo.shmmni;
 719 }
 720
 721 static void
 722 shminit(void *dummy)
 723 {
 724         int i;
 725
 726         shminfo.shmmax = shminfo.shmall * PAGE_SIZE;
 727         shmalloced = shminfo.shmmni;
 728         shmsegs = kmalloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
 729         for (i = 0; i < shmalloced; i++) {
 730                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
 731                 shmsegs[i].shm_perm.seq = 0;
 732         }
 733         shm_last_free = 0;
 734         shm_nused = 0;
 735         shm_committed = 0;
 736 }
 737 SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL);