1 /* $FreeBSD$ */ 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_rlimit.h" 36 #include "opt_sysvipc.h" 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/kernel.h> 41 #include <sys/lock.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/mutex.h> 48 #include <sys/stat.h> 49 #include <sys/syscall.h> 50 #include <sys/sysent.h> 51 #include <sys/sysproto.h> 52 #include <sys/jail.h> 53 54 #include <vm/vm.h> 55 #include <vm/vm_param.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 oshmctl __P((struct proc *p, struct oshmctl_args *uap)); 66 67 static int shmget_allocate_segment __P((struct proc *p, 68 struct shmget_args *uap, int mode)); 69 static int shmget_existing __P((struct proc *p, struct shmget_args *uap, 70 int mode, int segnum)); 71 72 /* XXX casting to (sy_call_t *) is bogus, as usual. */ 73 static sy_call_t *shmcalls[] = { 74 (sy_call_t *)shmat, (sy_call_t *)oshmctl, 75 (sy_call_t *)shmdt, (sy_call_t *)shmget, 76 (sy_call_t *)shmctl 77 }; 78 79 #define SHMSEG_FREE 0x0200 80 #define SHMSEG_REMOVED 0x0400 81 #define SHMSEG_ALLOCATED 0x0800 82 #define SHMSEG_WANTED 0x1000 83 84 static int shm_last_free, shm_nused, shm_committed, shmalloced; 85 static struct shmid_ds *shmsegs; 86 87 struct shm_handle { 88 /* vm_offset_t kva; */ 89 vm_object_t shm_object; 90 }; 91 92 struct shmmap_state { 93 vm_offset_t va; 94 int shmid; 95 }; 96 97 static void shm_deallocate_segment __P((struct shmid_ds *)); 98 static int shm_find_segment_by_key __P((key_t)); 99 static struct shmid_ds *shm_find_segment_by_shmid __P((int)); 100 static int shm_delete_mapping __P((struct proc *, struct shmmap_state *)); 101 static void shmrealloc __P((void)); 102 static void shminit __P((void)); 103 static int sysvshm_modload __P((struct module *, int, void *)); 104 static int shmunload __P((void)); 105 static void shmexit_myhook __P((struct proc *p)); 106 static void shmfork_myhook __P((struct proc *p1, struct proc *p2)); 107 static int sysctl_shmsegs __P((SYSCTL_HANDLER_ARGS)); 108 109 /* 110 * Tuneable values. 111 */ 112 #ifndef SHMMAXPGS 113 #define SHMMAXPGS 8192 /* Note: sysv shared memory is swap backed. */ 114 #endif 115 #ifndef SHMMAX 116 #define SHMMAX (SHMMAXPGS*PAGE_SIZE) 117 #endif 118 #ifndef SHMMIN 119 #define SHMMIN 1 120 #endif 121 #ifndef SHMMNI 122 #define SHMMNI 192 123 #endif 124 #ifndef SHMSEG 125 #define SHMSEG 128 126 #endif 127 #ifndef SHMALL 128 #define SHMALL (SHMMAXPGS) 129 #endif 130 131 struct shminfo shminfo = { 132 SHMMAX, 133 SHMMIN, 134 SHMMNI, 135 SHMSEG, 136 SHMALL 137 }; 138 139 static int shm_use_phys; 140 141 SYSCTL_DECL(_kern_ipc); 142 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, ""); 143 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, ""); 144 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0, ""); 145 SYSCTL_INT(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RD, &shminfo.shmseg, 0, ""); 146 SYSCTL_INT(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, ""); 147 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, 148 &shm_use_phys, 0, ""); 149 SYSCTL_PROC(_kern_ipc, OID_AUTO, shmsegs, CTLFLAG_RD, 150 NULL, 0, sysctl_shmsegs, "", ""); 151 152 static int 153 shm_find_segment_by_key(key) 154 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(shmid) 167 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(shmseg) 185 struct shmid_ds *shmseg; 186 { 187 struct shm_handle *shm_handle; 188 size_t size; 189 190 GIANT_REQUIRED; 191 192 shm_handle = shmseg->shm_internal; 193 vm_object_deallocate(shm_handle->shm_object); 194 free((caddr_t)shm_handle, M_SHM); 195 shmseg->shm_internal = NULL; 196 size = round_page(shmseg->shm_segsz); 197 shm_committed -= btoc(size); 198 shm_nused--; 199 shmseg->shm_perm.mode = SHMSEG_FREE; 200 } 201 202 static int 203 shm_delete_mapping(p, shmmap_s) 204 struct proc *p; 205 struct shmmap_state *shmmap_s; 206 { 207 struct shmid_ds *shmseg; 208 int segnum, result; 209 size_t size; 210 211 GIANT_REQUIRED; 212 213 segnum = IPCID_TO_IX(shmmap_s->shmid); 214 shmseg = &shmsegs[segnum]; 215 size = round_page(shmseg->shm_segsz); 216 result = vm_map_remove(&p->p_vmspace->vm_map, shmmap_s->va, 217 shmmap_s->va + size); 218 if (result != KERN_SUCCESS) 219 return EINVAL; 220 shmmap_s->shmid = -1; 221 shmseg->shm_dtime = time_second; 222 if ((--shmseg->shm_nattch <= 0) && 223 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { 224 shm_deallocate_segment(shmseg); 225 shm_last_free = segnum; 226 } 227 return 0; 228 } 229 230 #ifndef _SYS_SYSPROTO_H_ 231 struct shmdt_args { 232 void *shmaddr; 233 }; 234 #endif 235 236 /* 237 * MPSAFE 238 */ 239 int 240 shmdt(p, uap) 241 struct proc *p; 242 struct shmdt_args *uap; 243 { 244 struct shmmap_state *shmmap_s; 245 int i; 246 int error = 0; 247 248 mtx_lock(&Giant); 249 250 if (!jail_sysvipc_allowed && jailed(p->p_ucred)) { 251 error = ENOSYS; 252 goto done2; 253 } 254 255 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 256 if (shmmap_s == NULL) { 257 error = EINVAL; 258 goto done2; 259 } 260 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) { 261 if (shmmap_s->shmid != -1 && 262 shmmap_s->va == (vm_offset_t)uap->shmaddr) { 263 break; 264 } 265 } 266 if (i == shminfo.shmseg) { 267 error = EINVAL; 268 goto done2; 269 } 270 error = shm_delete_mapping(p, shmmap_s); 271 done2: 272 mtx_unlock(&Giant); 273 return (error); 274 } 275 276 #ifndef _SYS_SYSPROTO_H_ 277 struct shmat_args { 278 int shmid; 279 void *shmaddr; 280 int shmflg; 281 }; 282 #endif 283 284 /* 285 * MPSAFE 286 */ 287 int 288 shmat(p, uap) 289 struct proc *p; 290 struct shmat_args *uap; 291 { 292 int i, flags; 293 struct shmid_ds *shmseg; 294 struct shmmap_state *shmmap_s = NULL; 295 struct shm_handle *shm_handle; 296 vm_offset_t attach_va; 297 vm_prot_t prot; 298 vm_size_t size; 299 int rv; 300 int error = 0; 301 302 mtx_lock(&Giant); 303 304 if (!jail_sysvipc_allowed && jailed(p->p_ucred)) { 305 error = ENOSYS; 306 goto done2; 307 } 308 309 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 310 if (shmmap_s == NULL) { 311 size = shminfo.shmseg * sizeof(struct shmmap_state); 312 shmmap_s = malloc(size, M_SHM, M_WAITOK); 313 for (i = 0; i < shminfo.shmseg; i++) 314 shmmap_s[i].shmid = -1; 315 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 316 } 317 shmseg = shm_find_segment_by_shmid(uap->shmid); 318 if (shmseg == NULL) { 319 error = EINVAL; 320 goto done2; 321 } 322 error = ipcperm(p, &shmseg->shm_perm, 323 (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 324 if (error) 325 goto done2; 326 for (i = 0; i < shminfo.shmseg; i++) { 327 if (shmmap_s->shmid == -1) 328 break; 329 shmmap_s++; 330 } 331 if (i >= shminfo.shmseg) { 332 error = EMFILE; 333 goto done2; 334 } 335 size = round_page(shmseg->shm_segsz); 336 #ifdef VM_PROT_READ_IS_EXEC 337 prot = VM_PROT_READ | VM_PROT_EXECUTE; 338 #else 339 prot = VM_PROT_READ; 340 #endif 341 if ((uap->shmflg & SHM_RDONLY) == 0) 342 prot |= VM_PROT_WRITE; 343 flags = MAP_ANON | MAP_SHARED; 344 if (uap->shmaddr) { 345 flags |= MAP_FIXED; 346 if (uap->shmflg & SHM_RND) { 347 attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1); 348 } else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0) { 349 attach_va = (vm_offset_t)uap->shmaddr; 350 } else { 351 error = EINVAL; 352 goto done2; 353 } 354 } else { 355 /* 356 * This is just a hint to vm_map_find() about where to 357 * put it. 358 */ 359 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr 360 + MAXTSIZ + MAXDSIZ); 361 } 362 363 shm_handle = shmseg->shm_internal; 364 vm_object_reference(shm_handle->shm_object); 365 rv = vm_map_find(&p->p_vmspace->vm_map, shm_handle->shm_object, 366 0, &attach_va, size, (flags & MAP_FIXED)?0:1, prot, prot, 0); 367 if (rv != KERN_SUCCESS) { 368 error = ENOMEM; 369 goto done2; 370 } 371 vm_map_inherit(&p->p_vmspace->vm_map, 372 attach_va, attach_va + size, VM_INHERIT_SHARE); 373 374 shmmap_s->va = attach_va; 375 shmmap_s->shmid = uap->shmid; 376 shmseg->shm_lpid = p->p_pid; 377 shmseg->shm_atime = time_second; 378 shmseg->shm_nattch++; 379 p->p_retval[0] = attach_va; 380 done2: 381 mtx_unlock(&Giant); 382 return (error); 383 } 384 385 struct oshmid_ds { 386 struct ipc_perm shm_perm; /* operation perms */ 387 int shm_segsz; /* size of segment (bytes) */ 388 ushort shm_cpid; /* pid, creator */ 389 ushort shm_lpid; /* pid, last operation */ 390 short shm_nattch; /* no. of current attaches */ 391 time_t shm_atime; /* last attach time */ 392 time_t shm_dtime; /* last detach time */ 393 time_t shm_ctime; /* last change time */ 394 void *shm_handle; /* internal handle for shm segment */ 395 }; 396 397 struct oshmctl_args { 398 int shmid; 399 int cmd; 400 struct oshmid_ds *ubuf; 401 }; 402 403 /* 404 * MPSAFE 405 */ 406 static int 407 oshmctl(p, uap) 408 struct proc *p; 409 struct oshmctl_args *uap; 410 { 411 #ifdef COMPAT_43 412 int error = 0; 413 struct shmid_ds *shmseg; 414 struct oshmid_ds outbuf; 415 416 mtx_lock(&Giant); 417 418 if (!jail_sysvipc_allowed && jailed(p->p_ucred)) { 419 error = ENOSYS; 420 goto done2; 421 } 422 423 shmseg = shm_find_segment_by_shmid(uap->shmid); 424 if (shmseg == NULL) { 425 error = EINVAL; 426 goto done2; 427 } 428 switch (uap->cmd) { 429 case IPC_STAT: 430 error = ipcperm(p, &shmseg->shm_perm, IPC_R); 431 if (error) 432 goto done2; 433 outbuf.shm_perm = shmseg->shm_perm; 434 outbuf.shm_segsz = shmseg->shm_segsz; 435 outbuf.shm_cpid = shmseg->shm_cpid; 436 outbuf.shm_lpid = shmseg->shm_lpid; 437 outbuf.shm_nattch = shmseg->shm_nattch; 438 outbuf.shm_atime = shmseg->shm_atime; 439 outbuf.shm_dtime = shmseg->shm_dtime; 440 outbuf.shm_ctime = shmseg->shm_ctime; 441 outbuf.shm_handle = shmseg->shm_internal; 442 error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf)); 443 if (error) 444 goto done2; 445 break; 446 default: 447 /* XXX casting to (sy_call_t *) is bogus, as usual. */ 448 error = ((sy_call_t *)shmctl)(p, uap); 449 break; 450 } 451 done2: 452 mtx_unlock(&Giant); 453 return (error); 454 #else 455 return EINVAL; 456 #endif 457 } 458 459 #ifndef _SYS_SYSPROTO_H_ 460 struct shmctl_args { 461 int shmid; 462 int cmd; 463 struct shmid_ds *buf; 464 }; 465 #endif 466 467 /* 468 * MPSAFE 469 */ 470 int 471 shmctl(p, uap) 472 struct proc *p; 473 struct shmctl_args *uap; 474 { 475 int error = 0; 476 struct shmid_ds inbuf; 477 struct shmid_ds *shmseg; 478 479 mtx_lock(&Giant); 480 481 if (!jail_sysvipc_allowed && jailed(p->p_ucred)) { 482 error = ENOSYS; 483 goto done2; 484 } 485 486 shmseg = shm_find_segment_by_shmid(uap->shmid); 487 if (shmseg == NULL) { 488 error = EINVAL; 489 goto done2; 490 } 491 switch (uap->cmd) { 492 case IPC_STAT: 493 error = ipcperm(p, &shmseg->shm_perm, IPC_R); 494 if (error) 495 goto done2; 496 error = copyout((caddr_t)shmseg, uap->buf, sizeof(inbuf)); 497 if (error) 498 goto done2; 499 break; 500 case IPC_SET: 501 error = ipcperm(p, &shmseg->shm_perm, IPC_M); 502 if (error) 503 goto done2; 504 error = copyin(uap->buf, (caddr_t)&inbuf, sizeof(inbuf)); 505 if (error) 506 goto done2; 507 shmseg->shm_perm.uid = inbuf.shm_perm.uid; 508 shmseg->shm_perm.gid = inbuf.shm_perm.gid; 509 shmseg->shm_perm.mode = 510 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 511 (inbuf.shm_perm.mode & ACCESSPERMS); 512 shmseg->shm_ctime = time_second; 513 break; 514 case IPC_RMID: 515 error = ipcperm(p, &shmseg->shm_perm, IPC_M); 516 if (error) 517 goto done2; 518 shmseg->shm_perm.key = IPC_PRIVATE; 519 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 520 if (shmseg->shm_nattch <= 0) { 521 shm_deallocate_segment(shmseg); 522 shm_last_free = IPCID_TO_IX(uap->shmid); 523 } 524 break; 525 #if 0 526 case SHM_LOCK: 527 case SHM_UNLOCK: 528 #endif 529 default: 530 error = EINVAL; 531 break; 532 } 533 done2: 534 mtx_unlock(&Giant); 535 return (error); 536 } 537 538 #ifndef _SYS_SYSPROTO_H_ 539 struct shmget_args { 540 key_t key; 541 size_t size; 542 int shmflg; 543 }; 544 #endif 545 546 static int 547 shmget_existing(p, uap, mode, segnum) 548 struct proc *p; 549 struct shmget_args *uap; 550 int mode; 551 int segnum; 552 { 553 struct shmid_ds *shmseg; 554 int error; 555 556 shmseg = &shmsegs[segnum]; 557 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 558 /* 559 * This segment is in the process of being allocated. Wait 560 * until it's done, and look the key up again (in case the 561 * allocation failed or it was freed). 562 */ 563 shmseg->shm_perm.mode |= SHMSEG_WANTED; 564 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0); 565 if (error) 566 return error; 567 return EAGAIN; 568 } 569 if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL)) 570 return EEXIST; 571 error = ipcperm(p, &shmseg->shm_perm, mode); 572 if (error) 573 return error; 574 if (uap->size && uap->size > shmseg->shm_segsz) 575 return EINVAL; 576 p->p_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 577 return 0; 578 } 579 580 static int 581 shmget_allocate_segment(p, uap, mode) 582 struct proc *p; 583 struct shmget_args *uap; 584 int mode; 585 { 586 int i, segnum, shmid, size; 587 struct ucred *cred = p->p_ucred; 588 struct shmid_ds *shmseg; 589 struct shm_handle *shm_handle; 590 591 GIANT_REQUIRED; 592 593 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax) 594 return EINVAL; 595 if (shm_nused >= shminfo.shmmni) /* Any shmids left? */ 596 return ENOSPC; 597 size = round_page(uap->size); 598 if (shm_committed + btoc(size) > shminfo.shmall) 599 return ENOMEM; 600 if (shm_last_free < 0) { 601 shmrealloc(); /* Maybe expand the shmsegs[] array. */ 602 for (i = 0; i < shmalloced; i++) 603 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 604 break; 605 if (i == shmalloced) 606 return ENOSPC; 607 segnum = i; 608 } else { 609 segnum = shm_last_free; 610 shm_last_free = -1; 611 } 612 shmseg = &shmsegs[segnum]; 613 /* 614 * In case we sleep in malloc(), mark the segment present but deleted 615 * so that noone else tries to create the same key. 616 */ 617 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 618 shmseg->shm_perm.key = uap->key; 619 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff; 620 shm_handle = (struct shm_handle *) 621 malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK); 622 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 623 624 /* 625 * We make sure that we have allocated a pager before we need 626 * to. 627 */ 628 if (shm_use_phys) { 629 shm_handle->shm_object = 630 vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0); 631 } else { 632 shm_handle->shm_object = 633 vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0); 634 } 635 vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING); 636 vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT); 637 638 shmseg->shm_internal = shm_handle; 639 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 640 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 641 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 642 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 643 shmseg->shm_segsz = uap->size; 644 shmseg->shm_cpid = p->p_pid; 645 shmseg->shm_lpid = shmseg->shm_nattch = 0; 646 shmseg->shm_atime = shmseg->shm_dtime = 0; 647 shmseg->shm_ctime = time_second; 648 shm_committed += btoc(size); 649 shm_nused++; 650 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 651 /* 652 * Somebody else wanted this key while we were asleep. Wake 653 * them up now. 654 */ 655 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 656 wakeup((caddr_t)shmseg); 657 } 658 p->p_retval[0] = shmid; 659 return 0; 660 } 661 662 /* 663 * MPSAFE 664 */ 665 int 666 shmget(p, uap) 667 struct proc *p; 668 struct shmget_args *uap; 669 { 670 int segnum, mode; 671 int error; 672 673 mtx_lock(&Giant); 674 675 if (!jail_sysvipc_allowed && jailed(p->p_ucred)) { 676 error = ENOSYS; 677 goto done2; 678 } 679 680 mode = uap->shmflg & ACCESSPERMS; 681 if (uap->key != IPC_PRIVATE) { 682 again: 683 segnum = shm_find_segment_by_key(uap->key); 684 if (segnum >= 0) { 685 error = shmget_existing(p, uap, mode, segnum); 686 if (error == EAGAIN) 687 goto again; 688 goto done2; 689 } 690 if ((uap->shmflg & IPC_CREAT) == 0) { 691 error = ENOENT; 692 goto done2; 693 } 694 } 695 error = shmget_allocate_segment(p, uap, mode); 696 done2: 697 mtx_unlock(&Giant); 698 return (error); 699 } 700 701 /* 702 * MPSAFE 703 */ 704 int 705 shmsys(p, uap) 706 struct proc *p; 707 /* XXX actually varargs. */ 708 struct shmsys_args /* { 709 u_int which; 710 int a2; 711 int a3; 712 int a4; 713 } */ *uap; 714 { 715 int error; 716 717 mtx_lock(&Giant); 718 719 if (!jail_sysvipc_allowed && jailed(p->p_ucred)) { 720 error = ENOSYS; 721 goto done2; 722 } 723 724 if (uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0])) { 725 error = EINVAL; 726 goto done2; 727 } 728 error = (*shmcalls[uap->which])(p, &uap->a2); 729 done2: 730 mtx_unlock(&Giant); 731 return (error); 732 } 733 734 static void 735 shmfork_myhook(p1, p2) 736 struct proc *p1, *p2; 737 { 738 struct shmmap_state *shmmap_s; 739 size_t size; 740 int i; 741 742 size = shminfo.shmseg * sizeof(struct shmmap_state); 743 shmmap_s = malloc(size, M_SHM, M_WAITOK); 744 bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size); 745 p2->p_vmspace->vm_shm = (caddr_t)shmmap_s; 746 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 747 if (shmmap_s->shmid != -1) 748 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++; 749 } 750 751 static void 752 shmexit_myhook(p) 753 struct proc *p; 754 { 755 struct shmmap_state *shmmap_s; 756 int i; 757 758 GIANT_REQUIRED; 759 760 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 761 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 762 if (shmmap_s->shmid != -1) 763 shm_delete_mapping(p, shmmap_s); 764 free((caddr_t)p->p_vmspace->vm_shm, M_SHM); 765 p->p_vmspace->vm_shm = NULL; 766 } 767 768 static void 769 shmrealloc(void) 770 { 771 int i; 772 struct shmid_ds *newsegs; 773 774 if (shmalloced >= shminfo.shmmni) 775 return; 776 777 newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK); 778 if (newsegs == NULL) 779 return; 780 for (i = 0; i < shmalloced; i++) 781 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0])); 782 for (; i < shminfo.shmmni; i++) { 783 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 784 shmsegs[i].shm_perm.seq = 0; 785 } 786 free(shmsegs, M_SHM); 787 shmsegs = newsegs; 788 shmalloced = shminfo.shmmni; 789 } 790 791 static void 792 shminit() 793 { 794 int i; 795 796 shmalloced = shminfo.shmmni; 797 shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK); 798 if (shmsegs == NULL) 799 panic("cannot allocate initial memory for sysvshm"); 800 for (i = 0; i < shmalloced; i++) { 801 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 802 shmsegs[i].shm_perm.seq = 0; 803 } 804 shm_last_free = 0; 805 shm_nused = 0; 806 shm_committed = 0; 807 shmexit_hook = &shmexit_myhook; 808 shmfork_hook = &shmfork_myhook; 809 } 810 811 static int 812 shmunload() 813 { 814 815 if (shm_nused > 0) 816 return (EBUSY); 817 818 free(shmsegs, M_SHM); 819 shmexit_hook = NULL; 820 shmfork_hook = NULL; 821 return (0); 822 } 823 824 static int 825 sysctl_shmsegs(SYSCTL_HANDLER_ARGS) 826 { 827 828 return (SYSCTL_OUT(req, shmsegs, shmalloced * sizeof(shmsegs[0]))); 829 } 830 831 static int 832 sysvshm_modload(struct module *module, int cmd, void *arg) 833 { 834 int error = 0; 835 836 switch (cmd) { 837 case MOD_LOAD: 838 shminit(); 839 break; 840 case MOD_UNLOAD: 841 error = shmunload(); 842 break; 843 case MOD_SHUTDOWN: 844 break; 845 default: 846 error = EINVAL; 847 break; 848 } 849 return (error); 850 } 851 852 static moduledata_t sysvshm_mod = { 853 "sysvshm", 854 &sysvshm_modload, 855 NULL 856 }; 857 858 SYSCALL_MODULE_HELPER(shmsys, 4); 859 SYSCALL_MODULE_HELPER(shmat, 3); 860 SYSCALL_MODULE_HELPER(shmctl, 3); 861 SYSCALL_MODULE_HELPER(shmdt, 1); 862 SYSCALL_MODULE_HELPER(shmget, 3); 863 864 DECLARE_MODULE(sysvshm, sysvshm_mod, 865 SI_SUB_SYSV_SHM, SI_ORDER_FIRST); 866 MODULE_VERSION(sysvshm, 1); 867