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 <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 sys_oshmctl (struct proc *p, struct oshmctl_args *uap);
  64
  65 static int shmget_allocate_segment (struct proc *p, struct shmget_args *uap, int mode);
  66 static int shmget_existing (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 *)sys_shmat, (sy_call_t *)sys_oshmctl,
  71         (sy_call_t *)sys_shmdt, (sy_call_t *)sys_shmget,
  72         (sy_call_t *)sys_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 (struct shmid_ds *);
  94 static int shm_find_segment_by_key (key_t);
  95 static struct shmid_ds *shm_find_segment_by_shmid (int);
  96 static int shm_delete_mapping (struct vmspace *vm, struct shmmap_state *);
  97 static void shmrealloc (void);
  98 static void shminit (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_INT(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, "");
 139 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, "");
 140 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0, "");
 141 SYSCTL_INT(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RW, &shminfo.shmseg, 0, "");
 142 SYSCTL_INT(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, "");
 143 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, &shm_use_phys, 0, "");
 144
 145 static int
 146 shm_find_segment_by_key(key_t key)
 147 {
 148         int i;
 149
 150         for (i = 0; i < shmalloced; i++)
 151                 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) &&
 152                     shmsegs[i].shm_perm.key == key)
 153                         return i;
 154         return -1;
 155 }
 156
 157 static struct shmid_ds *
 158 shm_find_segment_by_shmid(int shmid)
 159 {
 160         int segnum;
 161         struct shmid_ds *shmseg;
 162
 163         segnum = IPCID_TO_IX(shmid);
 164         if (segnum < 0 || segnum >= shmalloced)
 165                 return NULL;
 166         shmseg = &shmsegs[segnum];
 167         if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED))
 168             != SHMSEG_ALLOCATED ||
 169             shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid))
 170                 return NULL;
 171         return shmseg;
 172 }
 173
 174 static void
 175 shm_deallocate_segment(struct shmid_ds *shmseg)
 176 {
 177         struct shm_handle *shm_handle;
 178         size_t size;
 179
 180         shm_handle = shmseg->shm_internal;
 181         vm_object_deallocate(shm_handle->shm_object);
 182         kfree((caddr_t)shm_handle, M_SHM);
 183         shmseg->shm_internal = NULL;
 184         size = round_page(shmseg->shm_segsz);
 185         shm_committed -= btoc(size);
 186         shm_nused--;
 187         shmseg->shm_perm.mode = SHMSEG_FREE;
 188 }
 189
 190 static int
 191 shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s)
 192 {
 193         struct shmid_ds *shmseg;
 194         int segnum, result;
 195         size_t size;
 196
 197         segnum = IPCID_TO_IX(shmmap_s->shmid);
 198         shmseg = &shmsegs[segnum];
 199         size = round_page(shmseg->shm_segsz);
 200         result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size);
 201         if (result != KERN_SUCCESS)
 202                 return EINVAL;
 203         shmmap_s->shmid = -1;
 204         shmseg->shm_dtime = time_second;
 205         if ((--shmseg->shm_nattch <= 0) &&
 206             (shmseg->shm_perm.mode & SHMSEG_REMOVED)) {
 207                 shm_deallocate_segment(shmseg);
 208                 shm_last_free = segnum;
 209         }
 210         return 0;
 211 }
 212
 213 /*
 214  * MPALMOSTSAFE
 215  */
 216 int
 217 sys_shmdt(struct shmdt_args *uap)
 218 {
 219         struct proc *p = curproc;
 220         struct shmmap_state *shmmap_s;
 221         int i;
 222         int error;
 223
 224         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 225                 return (ENOSYS);
 226
 227         get_mplock();
 228         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
 229         if (shmmap_s == NULL) {
 230                 error = EINVAL;
 231                 goto done;
 232         }
 233         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) {
 234                 if (shmmap_s->shmid != -1 &&
 235                     shmmap_s->va == (vm_offset_t)uap->shmaddr)
 236                         break;
 237         }
 238         if (i == shminfo.shmseg)
 239                 error = EINVAL;
 240         else
 241                 error = shm_delete_mapping(p->p_vmspace, shmmap_s);
 242 done:
 243         rel_mplock();
 244         return (error);
 245 }
 246
 247 /*
 248  * MPALMOSTSAFE
 249  */
 250 int
 251 sys_shmat(struct shmat_args *uap)
 252 {
 253         struct proc *p = curproc;
 254         int error, i, flags;
 255         struct shmid_ds *shmseg;
 256         struct shmmap_state *shmmap_s = NULL;
 257         struct shm_handle *shm_handle;
 258         vm_offset_t attach_va;
 259         vm_prot_t prot;
 260         vm_size_t size;
 261         int rv;
 262
 263         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 264                 return (ENOSYS);
 265
 266         get_mplock();
 267 again:
 268         shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
 269         if (shmmap_s == NULL) {
 270                 size = shminfo.shmseg * sizeof(struct shmmap_state);
 271                 shmmap_s = kmalloc(size, M_SHM, M_WAITOK);
 272                 for (i = 0; i < shminfo.shmseg; i++)
 273                         shmmap_s[i].shmid = -1;
 274                 if (p->p_vmspace->vm_shm != NULL) {
 275                         kfree(shmmap_s, M_SHM);
 276                         goto again;
 277                 }
 278                 p->p_vmspace->vm_shm = (caddr_t)shmmap_s;
 279         }
 280         shmseg = shm_find_segment_by_shmid(uap->shmid);
 281         if (shmseg == NULL) {
 282                 error = EINVAL;
 283                 goto done;
 284         }
 285         error = ipcperm(p, &shmseg->shm_perm,
 286                         (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
 287         if (error)
 288                 goto done;
 289         for (i = 0; i < shminfo.shmseg; i++) {
 290                 if (shmmap_s->shmid == -1)
 291                         break;
 292                 shmmap_s++;
 293         }
 294         if (i >= shminfo.shmseg) {
 295                 error = EMFILE;
 296                 goto done;
 297         }
 298         size = round_page(shmseg->shm_segsz);
 299 #ifdef VM_PROT_READ_IS_EXEC
 300         prot = VM_PROT_READ | VM_PROT_EXECUTE;
 301 #else
 302         prot = VM_PROT_READ;
 303 #endif
 304         if ((uap->shmflg & SHM_RDONLY) == 0)
 305                 prot |= VM_PROT_WRITE;
 306         flags = MAP_ANON | MAP_SHARED;
 307         if (uap->shmaddr) {
 308                 flags |= MAP_FIXED;
 309                 if (uap->shmflg & SHM_RND) {
 310                         attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1);
 311                 } else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0) {
 312                         attach_va = (vm_offset_t)uap->shmaddr;
 313                 } else {
 314                         error = EINVAL;
 315                         goto done;
 316                 }
 317         } else {
 318                 /*
 319                  * This is just a hint to vm_map_find() about where to put it.
 320                  */
 321                 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr + maxtsiz + maxdsiz);
 322         }
 323
 324         shm_handle = shmseg->shm_internal;
 325         vm_object_reference(shm_handle->shm_object);
 326         rv = vm_map_find(&p->p_vmspace->vm_map,
 327                          shm_handle->shm_object, 0,
 328                          &attach_va, size,
 329                          ((flags & MAP_FIXED) ? 0 : 1),
 330                          VM_MAPTYPE_NORMAL,
 331                          prot, prot,
 332                          0);
 333         if (rv != KERN_SUCCESS) {
 334                 vm_object_deallocate(shm_handle->shm_object);
 335                 error = ENOMEM;
 336                 goto done;
 337         }
 338         vm_map_inherit(&p->p_vmspace->vm_map,
 339                        attach_va, attach_va + size, VM_INHERIT_SHARE);
 340
 341         KKASSERT(shmmap_s->shmid == -1);
 342         shmmap_s->va = attach_va;
 343         shmmap_s->shmid = uap->shmid;
 344         shmseg->shm_lpid = p->p_pid;
 345         shmseg->shm_atime = time_second;
 346         shmseg->shm_nattch++;
 347         uap->sysmsg_result = attach_va;
 348         error = 0;
 349 done:
 350         rel_mplock();
 351         return error;
 352 }
 353
 354 struct oshmid_ds {
 355         struct  ipc_perm shm_perm;      /* operation perms */
 356         int     shm_segsz;              /* size of segment (bytes) */
 357         ushort  shm_cpid;               /* pid, creator */
 358         ushort  shm_lpid;               /* pid, last operation */
 359         short   shm_nattch;             /* no. of current attaches */
 360         time_t  shm_atime;              /* last attach time */
 361         time_t  shm_dtime;              /* last detach time */
 362         time_t  shm_ctime;              /* last change time */
 363         void    *shm_handle;            /* internal handle for shm segment */
 364 };
 365
 366 struct oshmctl_args {
 367         struct sysmsg sysmsg;
 368         int shmid;
 369         int cmd;
 370         struct oshmid_ds *ubuf;
 371 };
 372
 373 /*
 374  * MPALMOSTSAFE
 375  */
 376 static int
 377 sys_oshmctl(struct proc *p, struct oshmctl_args *uap)
 378 {
 379 #ifdef COMPAT_43
 380         int error;
 381         struct shmid_ds *shmseg;
 382         struct oshmid_ds outbuf;
 383
 384         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 385                 return (ENOSYS);
 386
 387         get_mplock();
 388         shmseg = shm_find_segment_by_shmid(uap->shmid);
 389         if (shmseg == NULL) {
 390                 error = EINVAL;
 391                 goto done;
 392         }
 393
 394         switch (uap->cmd) {
 395         case IPC_STAT:
 396                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
 397                 if (error)
 398                         break;
 399                 outbuf.shm_perm = shmseg->shm_perm;
 400                 outbuf.shm_segsz = shmseg->shm_segsz;
 401                 outbuf.shm_cpid = shmseg->shm_cpid;
 402                 outbuf.shm_lpid = shmseg->shm_lpid;
 403                 outbuf.shm_nattch = shmseg->shm_nattch;
 404                 outbuf.shm_atime = shmseg->shm_atime;
 405                 outbuf.shm_dtime = shmseg->shm_dtime;
 406                 outbuf.shm_ctime = shmseg->shm_ctime;
 407                 outbuf.shm_handle = shmseg->shm_internal;
 408                 error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf));
 409                 break;
 410         default:
 411                 /* XXX casting to (sy_call_t *) is bogus, as usual. */
 412                 error = sys_shmctl((struct shmctl_args *)uap);
 413         }
 414 done:
 415         rel_mplock();
 416         return error;
 417 #else
 418         return EINVAL;
 419 #endif
 420 }
 421
 422 /*
 423  * MPALMOSTSAFE
 424  */
 425 int
 426 sys_shmctl(struct shmctl_args *uap)
 427 {
 428         struct proc *p = curproc;
 429         int error;
 430         struct shmid_ds inbuf;
 431         struct shmid_ds *shmseg;
 432
 433         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 434                 return (ENOSYS);
 435
 436         get_mplock();
 437         shmseg = shm_find_segment_by_shmid(uap->shmid);
 438         if (shmseg == NULL) {
 439                 error = EINVAL;
 440                 goto done;
 441         }
 442
 443         switch (uap->cmd) {
 444         case IPC_STAT:
 445                 error = ipcperm(p, &shmseg->shm_perm, IPC_R);
 446                 if (error == 0)
 447                         error = copyout(shmseg, uap->buf, sizeof(inbuf));
 448                 break;
 449         case IPC_SET:
 450                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
 451                 if (error == 0)
 452                         error = copyin(uap->buf, &inbuf, sizeof(inbuf));
 453                 if (error == 0) {
 454                         shmseg->shm_perm.uid = inbuf.shm_perm.uid;
 455                         shmseg->shm_perm.gid = inbuf.shm_perm.gid;
 456                         shmseg->shm_perm.mode =
 457                             (shmseg->shm_perm.mode & ~ACCESSPERMS) |
 458                             (inbuf.shm_perm.mode & ACCESSPERMS);
 459                         shmseg->shm_ctime = time_second;
 460                 }
 461                 break;
 462         case IPC_RMID:
 463                 error = ipcperm(p, &shmseg->shm_perm, IPC_M);
 464                 if (error == 0) {
 465                         shmseg->shm_perm.key = IPC_PRIVATE;
 466                         shmseg->shm_perm.mode |= SHMSEG_REMOVED;
 467                         if (shmseg->shm_nattch <= 0) {
 468                                 shm_deallocate_segment(shmseg);
 469                                 shm_last_free = IPCID_TO_IX(uap->shmid);
 470                         }
 471                 }
 472                 break;
 473 #if 0
 474         case SHM_LOCK:
 475         case SHM_UNLOCK:
 476 #endif
 477         default:
 478                 error = EINVAL;
 479                 break;
 480         }
 481 done:
 482         rel_mplock();
 483         return error;
 484 }
 485
 486 static int
 487 shmget_existing(struct proc *p, struct shmget_args *uap, int mode, int segnum)
 488 {
 489         struct shmid_ds *shmseg;
 490         int error;
 491
 492         shmseg = &shmsegs[segnum];
 493         if (shmseg->shm_perm.mode & SHMSEG_REMOVED) {
 494                 /*
 495                  * This segment is in the process of being allocated.  Wait
 496                  * until it's done, and look the key up again (in case the
 497                  * allocation failed or it was freed).
 498                  */
 499                 shmseg->shm_perm.mode |= SHMSEG_WANTED;
 500                 error = tsleep((caddr_t)shmseg, PCATCH, "shmget", 0);
 501                 if (error)
 502                         return error;
 503                 return EAGAIN;
 504         }
 505         if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
 506                 return EEXIST;
 507         error = ipcperm(p, &shmseg->shm_perm, mode);
 508         if (error)
 509                 return error;
 510         if (uap->size && uap->size > shmseg->shm_segsz)
 511                 return EINVAL;
 512         uap->sysmsg_result = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
 513         return 0;
 514 }
 515
 516 static int
 517 shmget_allocate_segment(struct proc *p, struct shmget_args *uap, int mode)
 518 {
 519         int i, segnum, shmid, size;
 520         struct ucred *cred = p->p_ucred;
 521         struct shmid_ds *shmseg;
 522         struct shm_handle *shm_handle;
 523
 524         if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
 525                 return EINVAL;
 526         if (shm_nused >= shminfo.shmmni) /* any shmids left? */
 527                 return ENOSPC;
 528         size = round_page(uap->size);
 529         if (shm_committed + btoc(size) > shminfo.shmall)
 530                 return ENOMEM;
 531         if (shm_last_free < 0) {
 532                 shmrealloc();   /* maybe expand the shmsegs[] array */
 533                 for (i = 0; i < shmalloced; i++)
 534                         if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
 535                                 break;
 536                 if (i == shmalloced)
 537                         return ENOSPC;
 538                 segnum = i;
 539         } else  {
 540                 segnum = shm_last_free;
 541                 shm_last_free = -1;
 542         }
 543         shmseg = &shmsegs[segnum];
 544         /*
 545          * In case we sleep in malloc(), mark the segment present but deleted
 546          * so that noone else tries to create the same key.
 547          */
 548         shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
 549         shmseg->shm_perm.key = uap->key;
 550         shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff;
 551         shm_handle = kmalloc(sizeof(struct shm_handle), M_SHM, M_WAITOK);
 552         shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
 553
 554         /*
 555          * We make sure that we have allocated a pager before we need
 556          * to.
 557          */
 558         if (shm_use_phys) {
 559                 shm_handle->shm_object =
 560                     vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0);
 561         } else {
 562                 shm_handle->shm_object =
 563                     vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0);
 564         }
 565         vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING);
 566         vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT);
 567
 568         shmseg->shm_internal = shm_handle;
 569         shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid;
 570         shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid;
 571         shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
 572             (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
 573         shmseg->shm_segsz = uap->size;
 574         shmseg->shm_cpid = p->p_pid;
 575         shmseg->shm_lpid = shmseg->shm_nattch = 0;
 576         shmseg->shm_atime = shmseg->shm_dtime = 0;
 577         shmseg->shm_ctime = time_second;
 578         shm_committed += btoc(size);
 579         shm_nused++;
 580         if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
 581                 /*
 582                  * Somebody else wanted this key while we were asleep.  Wake
 583                  * them up now.
 584                  */
 585                 shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
 586                 wakeup((caddr_t)shmseg);
 587         }
 588         uap->sysmsg_result = shmid;
 589         return 0;
 590 }
 591
 592 /*
 593  * MPALMOSTSAFE
 594  */
 595 int
 596 sys_shmget(struct shmget_args *uap)
 597 {
 598         struct proc *p = curproc;
 599         int segnum, mode, error;
 600
 601         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 602                 return (ENOSYS);
 603
 604         mode = uap->shmflg & ACCESSPERMS;
 605         get_mplock();
 606
 607         if (uap->key != IPC_PRIVATE) {
 608         again:
 609                 segnum = shm_find_segment_by_key(uap->key);
 610                 if (segnum >= 0) {
 611                         error = shmget_existing(p, uap, mode, segnum);
 612                         if (error == EAGAIN)
 613                                 goto again;
 614                         goto done;
 615                 }
 616                 if ((uap->shmflg & IPC_CREAT) == 0) {
 617                         error = ENOENT;
 618                         goto done;
 619                 }
 620         }
 621         error = shmget_allocate_segment(p, uap, mode);
 622 done:
 623         rel_mplock();
 624         return (error);
 625 }
 626
 627 /*
 628  * shmsys_args(int which, int a2, ...) (VARARGS)
 629  *
 630  * MPALMOSTSAFE
 631  */
 632 int
 633 sys_shmsys(struct shmsys_args *uap)
 634 {
 635         struct proc *p = curproc;
 636         unsigned int which = (unsigned int)uap->which;
 637         int error;
 638
 639         if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL)
 640                 return (ENOSYS);
 641
 642         if (which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
 643                 return EINVAL;
 644         get_mplock();
 645         bcopy(&uap->a2, &uap->which,
 646                 sizeof(struct shmsys_args) - offsetof(struct shmsys_args, a2));
 647         error = ((*shmcalls[which])(uap));
 648         rel_mplock();
 649
 650         return(error);
 651 }
 652
 653 void
 654 shmfork(struct proc *p1, struct proc *p2)
 655 {
 656         struct shmmap_state *shmmap_s;
 657         size_t size;
 658         int i;
 659
 660         size = shminfo.shmseg * sizeof(struct shmmap_state);
 661         shmmap_s = kmalloc(size, M_SHM, M_WAITOK);
 662         bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size);
 663         p2->p_vmspace->vm_shm = (caddr_t)shmmap_s;
 664         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
 665                 if (shmmap_s->shmid != -1)
 666                         shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++;
 667 }
 668
 669 void
 670 shmexit(struct vmspace *vm)
 671 {
 672         struct shmmap_state *base, *shm;
 673         int i;
 674
 675         if ((base = (struct shmmap_state *)vm->vm_shm) != NULL) {
 676                 vm->vm_shm = NULL;
 677                 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) {
 678                         if (shm->shmid != -1)
 679                                 shm_delete_mapping(vm, shm);
 680                 }
 681                 kfree(base, M_SHM);
 682         }
 683 }
 684
 685 static void
 686 shmrealloc(void)
 687 {
 688         int i;
 689         struct shmid_ds *newsegs;
 690
 691         if (shmalloced >= shminfo.shmmni)
 692                 return;
 693
 694         newsegs = kmalloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
 695         for (i = 0; i < shmalloced; i++)
 696                 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
 697         for (; i < shminfo.shmmni; i++) {
 698                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
 699                 shmsegs[i].shm_perm.seq = 0;
 700         }
 701         kfree(shmsegs, M_SHM);
 702         shmsegs = newsegs;
 703         shmalloced = shminfo.shmmni;
 704 }
 705
 706 static void
 707 shminit(void *dummy)
 708 {
 709         int i;
 710
 711         shminfo.shmmax = shminfo.shmall * PAGE_SIZE;
 712         shmalloced = shminfo.shmmni;
 713         shmsegs = kmalloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
 714         for (i = 0; i < shmalloced; i++) {
 715                 shmsegs[i].shm_perm.mode = SHMSEG_FREE;
 716                 shmsegs[i].shm_perm.seq = 0;
 717         }
 718         shm_last_free = 0;
 719         shm_nused = 0;
 720         shm_committed = 0;
 721 }
 722 SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL);