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