1 /* $FreeBSD: src/sys/kern/sysv_shm.c,v 1.45.2.6 2002/10/22 20:45:03 fjoe Exp $ */ 2 /* $NetBSD: sysv_shm.c,v 1.23 1994/07/04 23:25:12 glass Exp $ */ 3 4 /* 5 * Copyright (c) 1994 Adam Glass and Charles Hannum. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Adam Glass and Charles 18 * Hannum. 19 * 4. The names of the authors may not be used to endorse or promote products 20 * derived from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #include "opt_compat.h" 35 #include "opt_sysvipc.h" 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/sysproto.h> 40 #include <sys/kernel.h> 41 #include <sys/sysctl.h> 42 #include <sys/shm.h> 43 #include <sys/proc.h> 44 #include <sys/malloc.h> 45 #include <sys/mman.h> 46 #include <sys/stat.h> 47 #include <sys/sysent.h> 48 #include <sys/jail.h> 49 50 #include <sys/mplock2.h> 51 52 #include <vm/vm.h> 53 #include <vm/vm_param.h> 54 #include <sys/lock.h> 55 #include <vm/pmap.h> 56 #include <vm/vm_object.h> 57 #include <vm/vm_map.h> 58 #include <vm/vm_page.h> 59 #include <vm/vm_pager.h> 60 61 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments"); 62 63 struct oshmctl_args; 64 static int sys_oshmctl (struct proc *p, struct oshmctl_args *uap); 65 66 static int shmget_allocate_segment (struct proc *p, struct shmget_args *uap, int mode); 67 static int shmget_existing (struct proc *p, struct shmget_args *uap, int mode, int segnum); 68 69 /* XXX casting to (sy_call_t *) is bogus, as usual. */ 70 static sy_call_t *shmcalls[] = { 71 (sy_call_t *)sys_shmat, (sy_call_t *)sys_oshmctl, 72 (sy_call_t *)sys_shmdt, (sy_call_t *)sys_shmget, 73 (sy_call_t *)sys_shmctl 74 }; 75 76 #define SHMSEG_FREE 0x0200 77 #define SHMSEG_REMOVED 0x0400 78 #define SHMSEG_ALLOCATED 0x0800 79 #define SHMSEG_WANTED 0x1000 80 81 static int shm_last_free, shm_committed, shmalloced; 82 int shm_nused; 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 "Max shared memory segment size"); 142 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, 143 "Min shared memory segment size"); 144 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0, 145 "Max number of shared memory identifiers"); 146 SYSCTL_INT(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RW, &shminfo.shmseg, 0, 147 "Max shared memory segments per process"); 148 SYSCTL_INT(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, 149 "Max pages of shared memory"); 150 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, &shm_use_phys, 0, 151 "Use phys pager allocation instead of swap pager allocation"); 152 153 static int 154 shm_find_segment_by_key(key_t key) 155 { 156 int i; 157 158 for (i = 0; i < shmalloced; i++) 159 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) && 160 shmsegs[i].shm_perm.key == key) 161 return i; 162 return -1; 163 } 164 165 static struct shmid_ds * 166 shm_find_segment_by_shmid(int shmid) 167 { 168 int segnum; 169 struct shmid_ds *shmseg; 170 171 segnum = IPCID_TO_IX(shmid); 172 if (segnum < 0 || segnum >= shmalloced) 173 return NULL; 174 shmseg = &shmsegs[segnum]; 175 if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED)) 176 != SHMSEG_ALLOCATED || 177 shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid)) 178 return NULL; 179 return shmseg; 180 } 181 182 static void 183 shm_deallocate_segment(struct shmid_ds *shmseg) 184 { 185 struct shm_handle *shm_handle; 186 size_t size; 187 188 shm_handle = shmseg->shm_internal; 189 vm_object_deallocate(shm_handle->shm_object); 190 kfree((caddr_t)shm_handle, M_SHM); 191 shmseg->shm_internal = NULL; 192 size = round_page(shmseg->shm_segsz); 193 shm_committed -= btoc(size); 194 shm_nused--; 195 shmseg->shm_perm.mode = SHMSEG_FREE; 196 } 197 198 static int 199 shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s) 200 { 201 struct shmid_ds *shmseg; 202 int segnum, result; 203 size_t size; 204 205 segnum = IPCID_TO_IX(shmmap_s->shmid); 206 shmseg = &shmsegs[segnum]; 207 size = round_page(shmseg->shm_segsz); 208 result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size); 209 if (result != KERN_SUCCESS) 210 return EINVAL; 211 shmmap_s->shmid = -1; 212 shmseg->shm_dtime = time_second; 213 if ((--shmseg->shm_nattch <= 0) && 214 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { 215 shm_deallocate_segment(shmseg); 216 shm_last_free = segnum; 217 } 218 return 0; 219 } 220 221 /* 222 * MPALMOSTSAFE 223 */ 224 int 225 sys_shmdt(struct shmdt_args *uap) 226 { 227 struct thread *td = curthread; 228 struct proc *p = td->td_proc; 229 struct shmmap_state *shmmap_s; 230 int i; 231 int error; 232 233 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) 234 return (ENOSYS); 235 236 get_mplock(); 237 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 238 if (shmmap_s == NULL) { 239 error = EINVAL; 240 goto done; 241 } 242 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) { 243 if (shmmap_s->shmid != -1 && 244 shmmap_s->va == (vm_offset_t)uap->shmaddr) 245 break; 246 } 247 if (i == shminfo.shmseg) 248 error = EINVAL; 249 else 250 error = shm_delete_mapping(p->p_vmspace, shmmap_s); 251 done: 252 rel_mplock(); 253 return (error); 254 } 255 256 /* 257 * MPALMOSTSAFE 258 */ 259 int 260 sys_shmat(struct shmat_args *uap) 261 { 262 struct thread *td = curthread; 263 struct proc *p = td->td_proc; 264 int error, i, flags; 265 struct shmid_ds *shmseg; 266 struct shmmap_state *shmmap_s = NULL; 267 struct shm_handle *shm_handle; 268 vm_offset_t attach_va; 269 vm_prot_t prot; 270 vm_size_t size; 271 int rv; 272 273 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) 274 return (ENOSYS); 275 276 get_mplock(); 277 again: 278 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 279 if (shmmap_s == NULL) { 280 size = shminfo.shmseg * sizeof(struct shmmap_state); 281 shmmap_s = kmalloc(size, M_SHM, M_WAITOK); 282 for (i = 0; i < shminfo.shmseg; i++) 283 shmmap_s[i].shmid = -1; 284 if (p->p_vmspace->vm_shm != NULL) { 285 kfree(shmmap_s, M_SHM); 286 goto again; 287 } 288 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 289 } 290 shmseg = shm_find_segment_by_shmid(uap->shmid); 291 if (shmseg == NULL) { 292 error = EINVAL; 293 goto done; 294 } 295 error = ipcperm(p, &shmseg->shm_perm, 296 (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 297 if (error) 298 goto done; 299 for (i = 0; i < shminfo.shmseg; i++) { 300 if (shmmap_s->shmid == -1) 301 break; 302 shmmap_s++; 303 } 304 if (i >= shminfo.shmseg) { 305 error = EMFILE; 306 goto done; 307 } 308 size = round_page(shmseg->shm_segsz); 309 #ifdef VM_PROT_READ_IS_EXEC 310 prot = VM_PROT_READ | VM_PROT_EXECUTE; 311 #else 312 prot = VM_PROT_READ; 313 #endif 314 if ((uap->shmflg & SHM_RDONLY) == 0) 315 prot |= VM_PROT_WRITE; 316 flags = MAP_ANON | MAP_SHARED; 317 if (uap->shmaddr) { 318 flags |= MAP_FIXED; 319 if (uap->shmflg & SHM_RND) { 320 attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1); 321 } else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0) { 322 attach_va = (vm_offset_t)uap->shmaddr; 323 } else { 324 error = EINVAL; 325 goto done; 326 } 327 } else { 328 /* 329 * This is just a hint to vm_map_find() about where to put it. 330 */ 331 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr + maxtsiz + maxdsiz); 332 } 333 334 shm_handle = shmseg->shm_internal; 335 vm_object_reference(shm_handle->shm_object); 336 rv = vm_map_find(&p->p_vmspace->vm_map, 337 shm_handle->shm_object, 0, 338 &attach_va, 339 size, PAGE_SIZE, 340 ((flags & MAP_FIXED) ? 0 : 1), 341 VM_MAPTYPE_NORMAL, 342 prot, prot, 343 0); 344 if (rv != KERN_SUCCESS) { 345 vm_object_deallocate(shm_handle->shm_object); 346 error = ENOMEM; 347 goto done; 348 } 349 vm_map_inherit(&p->p_vmspace->vm_map, 350 attach_va, attach_va + size, VM_INHERIT_SHARE); 351 352 KKASSERT(shmmap_s->shmid == -1); 353 shmmap_s->va = attach_va; 354 shmmap_s->shmid = uap->shmid; 355 shmseg->shm_lpid = p->p_pid; 356 shmseg->shm_atime = time_second; 357 shmseg->shm_nattch++; 358 uap->sysmsg_resultp = (void *)attach_va; 359 error = 0; 360 done: 361 rel_mplock(); 362 return error; 363 } 364 365 struct oshmid_ds { 366 struct ipc_perm shm_perm; /* operation perms */ 367 int shm_segsz; /* size of segment (bytes) */ 368 ushort shm_cpid; /* pid, creator */ 369 ushort shm_lpid; /* pid, last operation */ 370 short shm_nattch; /* no. of current attaches */ 371 time_t shm_atime; /* last attach time */ 372 time_t shm_dtime; /* last detach time */ 373 time_t shm_ctime; /* last change time */ 374 void *shm_handle; /* internal handle for shm segment */ 375 }; 376 377 struct oshmctl_args { 378 struct sysmsg sysmsg; 379 int shmid; 380 int cmd; 381 struct oshmid_ds *ubuf; 382 }; 383 384 /* 385 * MPALMOSTSAFE 386 */ 387 static int 388 sys_oshmctl(struct proc *p, struct oshmctl_args *uap) 389 { 390 #ifdef COMPAT_43 391 struct thread *td = curthread; 392 struct shmid_ds *shmseg; 393 struct oshmid_ds outbuf; 394 int error; 395 396 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) 397 return (ENOSYS); 398 399 get_mplock(); 400 shmseg = shm_find_segment_by_shmid(uap->shmid); 401 if (shmseg == NULL) { 402 error = EINVAL; 403 goto done; 404 } 405 406 switch (uap->cmd) { 407 case IPC_STAT: 408 error = ipcperm(p, &shmseg->shm_perm, IPC_R); 409 if (error) 410 break; 411 outbuf.shm_perm = shmseg->shm_perm; 412 outbuf.shm_segsz = shmseg->shm_segsz; 413 outbuf.shm_cpid = shmseg->shm_cpid; 414 outbuf.shm_lpid = shmseg->shm_lpid; 415 outbuf.shm_nattch = shmseg->shm_nattch; 416 outbuf.shm_atime = shmseg->shm_atime; 417 outbuf.shm_dtime = shmseg->shm_dtime; 418 outbuf.shm_ctime = shmseg->shm_ctime; 419 outbuf.shm_handle = shmseg->shm_internal; 420 error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf)); 421 break; 422 default: 423 /* XXX casting to (sy_call_t *) is bogus, as usual. */ 424 error = sys_shmctl((struct shmctl_args *)uap); 425 } 426 done: 427 rel_mplock(); 428 return error; 429 #else 430 return EINVAL; 431 #endif 432 } 433 434 /* 435 * MPALMOSTSAFE 436 */ 437 int 438 sys_shmctl(struct shmctl_args *uap) 439 { 440 struct thread *td = curthread; 441 struct proc *p = td->td_proc; 442 int error; 443 struct shmid_ds inbuf; 444 struct shmid_ds *shmseg; 445 446 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) 447 return (ENOSYS); 448 449 get_mplock(); 450 shmseg = shm_find_segment_by_shmid(uap->shmid); 451 if (shmseg == NULL) { 452 error = EINVAL; 453 goto done; 454 } 455 456 switch (uap->cmd) { 457 case IPC_STAT: 458 error = ipcperm(p, &shmseg->shm_perm, IPC_R); 459 if (error == 0) 460 error = copyout(shmseg, uap->buf, sizeof(inbuf)); 461 break; 462 case IPC_SET: 463 error = ipcperm(p, &shmseg->shm_perm, IPC_M); 464 if (error == 0) 465 error = copyin(uap->buf, &inbuf, sizeof(inbuf)); 466 if (error == 0) { 467 shmseg->shm_perm.uid = inbuf.shm_perm.uid; 468 shmseg->shm_perm.gid = inbuf.shm_perm.gid; 469 shmseg->shm_perm.mode = 470 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 471 (inbuf.shm_perm.mode & ACCESSPERMS); 472 shmseg->shm_ctime = time_second; 473 } 474 break; 475 case IPC_RMID: 476 error = ipcperm(p, &shmseg->shm_perm, IPC_M); 477 if (error == 0) { 478 shmseg->shm_perm.key = IPC_PRIVATE; 479 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 480 if (shmseg->shm_nattch <= 0) { 481 shm_deallocate_segment(shmseg); 482 shm_last_free = IPCID_TO_IX(uap->shmid); 483 } 484 } 485 break; 486 #if 0 487 case SHM_LOCK: 488 case SHM_UNLOCK: 489 #endif 490 default: 491 error = EINVAL; 492 break; 493 } 494 done: 495 rel_mplock(); 496 return error; 497 } 498 499 static int 500 shmget_existing(struct proc *p, struct shmget_args *uap, int mode, int segnum) 501 { 502 struct shmid_ds *shmseg; 503 int error; 504 505 shmseg = &shmsegs[segnum]; 506 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 507 /* 508 * This segment is in the process of being allocated. Wait 509 * until it's done, and look the key up again (in case the 510 * allocation failed or it was freed). 511 */ 512 shmseg->shm_perm.mode |= SHMSEG_WANTED; 513 error = tsleep((caddr_t)shmseg, PCATCH, "shmget", 0); 514 if (error) 515 return error; 516 return EAGAIN; 517 } 518 if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL)) 519 return EEXIST; 520 error = ipcperm(p, &shmseg->shm_perm, mode); 521 if (error) 522 return error; 523 if (uap->size && uap->size > shmseg->shm_segsz) 524 return EINVAL; 525 uap->sysmsg_result = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 526 return 0; 527 } 528 529 static int 530 shmget_allocate_segment(struct proc *p, struct shmget_args *uap, int mode) 531 { 532 int i, segnum, shmid, size; 533 struct ucred *cred = p->p_ucred; 534 struct shmid_ds *shmseg; 535 struct shm_handle *shm_handle; 536 537 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax) 538 return EINVAL; 539 if (shm_nused >= shminfo.shmmni) /* any shmids left? */ 540 return ENOSPC; 541 size = round_page(uap->size); 542 if (shm_committed + btoc(size) > shminfo.shmall) 543 return ENOMEM; 544 if (shm_last_free < 0) { 545 shmrealloc(); /* maybe expand the shmsegs[] array */ 546 for (i = 0; i < shmalloced; i++) 547 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 548 break; 549 if (i == shmalloced) 550 return ENOSPC; 551 segnum = i; 552 } else { 553 segnum = shm_last_free; 554 shm_last_free = -1; 555 } 556 shmseg = &shmsegs[segnum]; 557 /* 558 * In case we sleep in malloc(), mark the segment present but deleted 559 * so that noone else tries to create the same key. 560 */ 561 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 562 shmseg->shm_perm.key = uap->key; 563 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff; 564 shm_handle = kmalloc(sizeof(struct shm_handle), M_SHM, M_WAITOK); 565 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 566 567 /* 568 * We make sure that we have allocated a pager before we need 569 * to. 570 */ 571 if (shm_use_phys) { 572 shm_handle->shm_object = 573 phys_pager_alloc(NULL, size, VM_PROT_DEFAULT, 0); 574 } else { 575 shm_handle->shm_object = 576 swap_pager_alloc(NULL, size, VM_PROT_DEFAULT, 0); 577 } 578 vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING); 579 vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT); 580 581 shmseg->shm_internal = shm_handle; 582 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 583 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 584 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 585 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 586 shmseg->shm_segsz = uap->size; 587 shmseg->shm_cpid = p->p_pid; 588 shmseg->shm_lpid = shmseg->shm_nattch = 0; 589 shmseg->shm_atime = shmseg->shm_dtime = 0; 590 shmseg->shm_ctime = time_second; 591 shm_committed += btoc(size); 592 shm_nused++; 593 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 594 /* 595 * Somebody else wanted this key while we were asleep. Wake 596 * them up now. 597 */ 598 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 599 wakeup((caddr_t)shmseg); 600 } 601 uap->sysmsg_result = shmid; 602 return 0; 603 } 604 605 /* 606 * MPALMOSTSAFE 607 */ 608 int 609 sys_shmget(struct shmget_args *uap) 610 { 611 struct thread *td = curthread; 612 struct proc *p = td->td_proc; 613 int segnum, mode, error; 614 615 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) 616 return (ENOSYS); 617 618 mode = uap->shmflg & ACCESSPERMS; 619 get_mplock(); 620 621 if (uap->key != IPC_PRIVATE) { 622 again: 623 segnum = shm_find_segment_by_key(uap->key); 624 if (segnum >= 0) { 625 error = shmget_existing(p, uap, mode, segnum); 626 if (error == EAGAIN) 627 goto again; 628 goto done; 629 } 630 if ((uap->shmflg & IPC_CREAT) == 0) { 631 error = ENOENT; 632 goto done; 633 } 634 } 635 error = shmget_allocate_segment(p, uap, mode); 636 done: 637 rel_mplock(); 638 return (error); 639 } 640 641 /* 642 * shmsys_args(int which, int a2, ...) (VARARGS) 643 * 644 * MPALMOSTSAFE 645 */ 646 int 647 sys_shmsys(struct shmsys_args *uap) 648 { 649 struct thread *td = curthread; 650 unsigned int which = (unsigned int)uap->which; 651 int error; 652 653 if (!jail_sysvipc_allowed && td->td_ucred->cr_prison != NULL) 654 return (ENOSYS); 655 656 if (which >= NELEM(shmcalls)) 657 return EINVAL; 658 get_mplock(); 659 bcopy(&uap->a2, &uap->which, 660 sizeof(struct shmsys_args) - offsetof(struct shmsys_args, a2)); 661 error = ((*shmcalls[which])(uap)); 662 rel_mplock(); 663 664 return(error); 665 } 666 667 void 668 shmfork(struct proc *p1, struct proc *p2) 669 { 670 struct shmmap_state *shmmap_s; 671 size_t size; 672 int i; 673 674 size = shminfo.shmseg * sizeof(struct shmmap_state); 675 shmmap_s = kmalloc(size, M_SHM, M_WAITOK); 676 bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size); 677 p2->p_vmspace->vm_shm = (caddr_t)shmmap_s; 678 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 679 if (shmmap_s->shmid != -1) 680 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++; 681 } 682 683 void 684 shmexit(struct vmspace *vm) 685 { 686 struct shmmap_state *base, *shm; 687 int i; 688 689 if ((base = (struct shmmap_state *)vm->vm_shm) != NULL) { 690 vm->vm_shm = NULL; 691 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) { 692 if (shm->shmid != -1) 693 shm_delete_mapping(vm, shm); 694 } 695 kfree(base, M_SHM); 696 } 697 } 698 699 static void 700 shmrealloc(void) 701 { 702 int i; 703 struct shmid_ds *newsegs; 704 705 if (shmalloced >= shminfo.shmmni) 706 return; 707 708 newsegs = kmalloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK); 709 for (i = 0; i < shmalloced; i++) 710 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0])); 711 for (; i < shminfo.shmmni; i++) { 712 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 713 shmsegs[i].shm_perm.seq = 0; 714 } 715 kfree(shmsegs, M_SHM); 716 shmsegs = newsegs; 717 shmalloced = shminfo.shmmni; 718 } 719 720 static void 721 shminit(void *dummy) 722 { 723 int i; 724 725 shminfo.shmmax = shminfo.shmall * PAGE_SIZE; 726 shmalloced = shminfo.shmmni; 727 shmsegs = kmalloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK); 728 for (i = 0; i < shmalloced; i++) { 729 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 730 shmsegs[i].shm_perm.seq = 0; 731 } 732 shm_last_free = 0; 733 shm_nused = 0; 734 shm_committed = 0; 735 } 736 SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL); 737