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 mtx_assert(&vm_mtx, MA_OWNED); /* For vm_object_deallocate. */ 191 shm_handle = shmseg->shm_internal; 192 vm_object_deallocate(shm_handle->shm_object); 193 free((caddr_t)shm_handle, M_SHM); 194 shmseg->shm_internal = NULL; 195 size = round_page(shmseg->shm_segsz); 196 shm_committed -= btoc(size); 197 shm_nused--; 198 shmseg->shm_perm.mode = SHMSEG_FREE; 199 } 200 201 static int 202 shm_delete_mapping(p, shmmap_s) 203 struct proc *p; 204 struct shmmap_state *shmmap_s; 205 { 206 struct shmid_ds *shmseg; 207 int segnum, result; 208 size_t size; 209 210 /* For vm_map_remove and shm_deallocate_segment. */ 211 mtx_assert(&vm_mtx, MA_OWNED); 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 int 237 shmdt(p, uap) 238 struct proc *p; 239 struct shmdt_args *uap; 240 { 241 struct shmmap_state *shmmap_s; 242 int i; 243 int error; 244 245 if (!jail_sysvipc_allowed && jailed(p->p_ucred)) 246 return (ENOSYS); 247 248 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 249 if (shmmap_s == NULL) 250 return EINVAL; 251 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 252 if (shmmap_s->shmid != -1 && 253 shmmap_s->va == (vm_offset_t)uap->shmaddr) 254 break; 255 if (i == shminfo.shmseg) 256 return EINVAL; 257 mtx_lock(&vm_mtx); 258 error = shm_delete_mapping(p, shmmap_s); 259 mtx_unlock(&vm_mtx); 260 return error; 261 } 262 263 #ifndef _SYS_SYSPROTO_H_ 264 struct shmat_args { 265 int shmid; 266 void *shmaddr; 267 int shmflg; 268 }; 269 #endif 270 271 int 272 shmat(p, uap) 273 struct proc *p; 274 struct shmat_args *uap; 275 { 276 int error, i, flags; 277 struct shmid_ds *shmseg; 278 struct shmmap_state *shmmap_s = NULL; 279 struct shm_handle *shm_handle; 280 vm_offset_t attach_va; 281 vm_prot_t prot; 282 vm_size_t size; 283 int rv; 284 285 if (!jail_sysvipc_allowed && jailed(p->p_ucred)) 286 return (ENOSYS); 287 288 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 289 if (shmmap_s == NULL) { 290 size = shminfo.shmseg * sizeof(struct shmmap_state); 291 shmmap_s = malloc(size, M_SHM, M_WAITOK); 292 for (i = 0; i < shminfo.shmseg; i++) 293 shmmap_s[i].shmid = -1; 294 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 295 } 296 shmseg = shm_find_segment_by_shmid(uap->shmid); 297 if (shmseg == NULL) 298 return EINVAL; 299 error = ipcperm(p, &shmseg->shm_perm, 300 (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 301 if (error) 302 return error; 303 for (i = 0; i < shminfo.shmseg; i++) { 304 if (shmmap_s->shmid == -1) 305 break; 306 shmmap_s++; 307 } 308 if (i >= shminfo.shmseg) 309 return EMFILE; 310 size = round_page(shmseg->shm_segsz); 311 #ifdef VM_PROT_READ_IS_EXEC 312 prot = VM_PROT_READ | VM_PROT_EXECUTE; 313 #else 314 prot = VM_PROT_READ; 315 #endif 316 if ((uap->shmflg & SHM_RDONLY) == 0) 317 prot |= VM_PROT_WRITE; 318 flags = MAP_ANON | MAP_SHARED; 319 if (uap->shmaddr) { 320 flags |= MAP_FIXED; 321 if (uap->shmflg & SHM_RND) 322 attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1); 323 else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0) 324 attach_va = (vm_offset_t)uap->shmaddr; 325 else 326 return EINVAL; 327 } else { 328 /* 329 * This is just a hint to vm_map_find() about where to 330 * put it. 331 */ 332 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr 333 + MAXTSIZ + MAXDSIZ); 334 } 335 336 shm_handle = shmseg->shm_internal; 337 mtx_lock(&vm_mtx); 338 vm_object_reference(shm_handle->shm_object); 339 rv = vm_map_find(&p->p_vmspace->vm_map, shm_handle->shm_object, 340 0, &attach_va, size, (flags & MAP_FIXED)?0:1, prot, prot, 0); 341 if (rv != KERN_SUCCESS) { 342 mtx_unlock(&vm_mtx); 343 return ENOMEM; 344 } 345 vm_map_inherit(&p->p_vmspace->vm_map, 346 attach_va, attach_va + size, VM_INHERIT_SHARE); 347 mtx_unlock(&vm_mtx); 348 349 shmmap_s->va = attach_va; 350 shmmap_s->shmid = uap->shmid; 351 shmseg->shm_lpid = p->p_pid; 352 shmseg->shm_atime = time_second; 353 shmseg->shm_nattch++; 354 p->p_retval[0] = attach_va; 355 return 0; 356 } 357 358 struct oshmid_ds { 359 struct ipc_perm shm_perm; /* operation perms */ 360 int shm_segsz; /* size of segment (bytes) */ 361 ushort shm_cpid; /* pid, creator */ 362 ushort shm_lpid; /* pid, last operation */ 363 short shm_nattch; /* no. of current attaches */ 364 time_t shm_atime; /* last attach time */ 365 time_t shm_dtime; /* last detach time */ 366 time_t shm_ctime; /* last change time */ 367 void *shm_handle; /* internal handle for shm segment */ 368 }; 369 370 struct oshmctl_args { 371 int shmid; 372 int cmd; 373 struct oshmid_ds *ubuf; 374 }; 375 376 static int 377 oshmctl(p, uap) 378 struct proc *p; 379 struct oshmctl_args *uap; 380 { 381 #ifdef COMPAT_43 382 int error; 383 struct shmid_ds *shmseg; 384 struct oshmid_ds outbuf; 385 386 if (!jail_sysvipc_allowed && jailed(p->p_ucred)) 387 return (ENOSYS); 388 389 shmseg = shm_find_segment_by_shmid(uap->shmid); 390 if (shmseg == NULL) 391 return EINVAL; 392 switch (uap->cmd) { 393 case IPC_STAT: 394 error = ipcperm(p, &shmseg->shm_perm, IPC_R); 395 if (error) 396 return error; 397 outbuf.shm_perm = shmseg->shm_perm; 398 outbuf.shm_segsz = shmseg->shm_segsz; 399 outbuf.shm_cpid = shmseg->shm_cpid; 400 outbuf.shm_lpid = shmseg->shm_lpid; 401 outbuf.shm_nattch = shmseg->shm_nattch; 402 outbuf.shm_atime = shmseg->shm_atime; 403 outbuf.shm_dtime = shmseg->shm_dtime; 404 outbuf.shm_ctime = shmseg->shm_ctime; 405 outbuf.shm_handle = shmseg->shm_internal; 406 error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf)); 407 if (error) 408 return error; 409 break; 410 default: 411 /* XXX casting to (sy_call_t *) is bogus, as usual. */ 412 return ((sy_call_t *)shmctl)(p, uap); 413 } 414 return 0; 415 #else 416 return EINVAL; 417 #endif 418 } 419 420 #ifndef _SYS_SYSPROTO_H_ 421 struct shmctl_args { 422 int shmid; 423 int cmd; 424 struct shmid_ds *buf; 425 }; 426 #endif 427 428 int 429 shmctl(p, uap) 430 struct proc *p; 431 struct shmctl_args *uap; 432 { 433 int error; 434 struct shmid_ds inbuf; 435 struct shmid_ds *shmseg; 436 437 if (!jail_sysvipc_allowed && jailed(p->p_ucred)) 438 return (ENOSYS); 439 440 shmseg = shm_find_segment_by_shmid(uap->shmid); 441 if (shmseg == NULL) 442 return EINVAL; 443 switch (uap->cmd) { 444 case IPC_STAT: 445 error = ipcperm(p, &shmseg->shm_perm, IPC_R); 446 if (error) 447 return error; 448 error = copyout((caddr_t)shmseg, uap->buf, sizeof(inbuf)); 449 if (error) 450 return error; 451 break; 452 case IPC_SET: 453 error = ipcperm(p, &shmseg->shm_perm, IPC_M); 454 if (error) 455 return error; 456 error = copyin(uap->buf, (caddr_t)&inbuf, sizeof(inbuf)); 457 if (error) 458 return error; 459 shmseg->shm_perm.uid = inbuf.shm_perm.uid; 460 shmseg->shm_perm.gid = inbuf.shm_perm.gid; 461 shmseg->shm_perm.mode = 462 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 463 (inbuf.shm_perm.mode & ACCESSPERMS); 464 shmseg->shm_ctime = time_second; 465 break; 466 case IPC_RMID: 467 error = ipcperm(p, &shmseg->shm_perm, IPC_M); 468 if (error) 469 return error; 470 shmseg->shm_perm.key = IPC_PRIVATE; 471 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 472 if (shmseg->shm_nattch <= 0) { 473 mtx_lock(&vm_mtx); 474 shm_deallocate_segment(shmseg); 475 mtx_unlock(&vm_mtx); 476 shm_last_free = IPCID_TO_IX(uap->shmid); 477 } 478 break; 479 #if 0 480 case SHM_LOCK: 481 case SHM_UNLOCK: 482 #endif 483 default: 484 return EINVAL; 485 } 486 return 0; 487 } 488 489 #ifndef _SYS_SYSPROTO_H_ 490 struct shmget_args { 491 key_t key; 492 size_t size; 493 int shmflg; 494 }; 495 #endif 496 497 static int 498 shmget_existing(p, uap, mode, segnum) 499 struct proc *p; 500 struct shmget_args *uap; 501 int mode; 502 int segnum; 503 { 504 struct shmid_ds *shmseg; 505 int error; 506 507 shmseg = &shmsegs[segnum]; 508 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 509 /* 510 * This segment is in the process of being allocated. Wait 511 * until it's done, and look the key up again (in case the 512 * allocation failed or it was freed). 513 */ 514 shmseg->shm_perm.mode |= SHMSEG_WANTED; 515 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0); 516 if (error) 517 return error; 518 return EAGAIN; 519 } 520 if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL)) 521 return EEXIST; 522 error = ipcperm(p, &shmseg->shm_perm, mode); 523 if (error) 524 return error; 525 if (uap->size && uap->size > shmseg->shm_segsz) 526 return EINVAL; 527 p->p_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 528 return 0; 529 } 530 531 static int 532 shmget_allocate_segment(p, uap, mode) 533 struct proc *p; 534 struct shmget_args *uap; 535 int mode; 536 { 537 int i, segnum, shmid, size; 538 struct ucred *cred = p->p_ucred; 539 struct shmid_ds *shmseg; 540 struct shm_handle *shm_handle; 541 542 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax) 543 return EINVAL; 544 if (shm_nused >= shminfo.shmmni) /* Any shmids left? */ 545 return ENOSPC; 546 size = round_page(uap->size); 547 if (shm_committed + btoc(size) > shminfo.shmall) 548 return ENOMEM; 549 if (shm_last_free < 0) { 550 shmrealloc(); /* Maybe expand the shmsegs[] array. */ 551 for (i = 0; i < shmalloced; i++) 552 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 553 break; 554 if (i == shmalloced) 555 return ENOSPC; 556 segnum = i; 557 } else { 558 segnum = shm_last_free; 559 shm_last_free = -1; 560 } 561 shmseg = &shmsegs[segnum]; 562 /* 563 * In case we sleep in malloc(), mark the segment present but deleted 564 * so that noone else tries to create the same key. 565 */ 566 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 567 shmseg->shm_perm.key = uap->key; 568 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff; 569 shm_handle = (struct shm_handle *) 570 malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK); 571 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 572 573 /* 574 * We make sure that we have allocated a pager before we need 575 * to. 576 */ 577 mtx_lock(&vm_mtx); 578 if (shm_use_phys) { 579 shm_handle->shm_object = 580 vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0); 581 } else { 582 shm_handle->shm_object = 583 vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0); 584 } 585 vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING); 586 vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT); 587 mtx_unlock(&vm_mtx); 588 589 shmseg->shm_internal = shm_handle; 590 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 591 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 592 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 593 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 594 shmseg->shm_segsz = uap->size; 595 shmseg->shm_cpid = p->p_pid; 596 shmseg->shm_lpid = shmseg->shm_nattch = 0; 597 shmseg->shm_atime = shmseg->shm_dtime = 0; 598 shmseg->shm_ctime = time_second; 599 shm_committed += btoc(size); 600 shm_nused++; 601 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 602 /* 603 * Somebody else wanted this key while we were asleep. Wake 604 * them up now. 605 */ 606 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 607 wakeup((caddr_t)shmseg); 608 } 609 p->p_retval[0] = shmid; 610 return 0; 611 } 612 613 int 614 shmget(p, uap) 615 struct proc *p; 616 struct shmget_args *uap; 617 { 618 int segnum, mode, error; 619 620 if (!jail_sysvipc_allowed && jailed(p->p_ucred)) 621 return (ENOSYS); 622 623 mode = uap->shmflg & ACCESSPERMS; 624 if (uap->key != IPC_PRIVATE) { 625 again: 626 segnum = shm_find_segment_by_key(uap->key); 627 if (segnum >= 0) { 628 error = shmget_existing(p, uap, mode, segnum); 629 if (error == EAGAIN) 630 goto again; 631 return error; 632 } 633 if ((uap->shmflg & IPC_CREAT) == 0) 634 return ENOENT; 635 } 636 return shmget_allocate_segment(p, uap, mode); 637 } 638 639 int 640 shmsys(p, uap) 641 struct proc *p; 642 /* XXX actually varargs. */ 643 struct shmsys_args /* { 644 u_int which; 645 int a2; 646 int a3; 647 int a4; 648 } */ *uap; 649 { 650 651 if (!jail_sysvipc_allowed && jailed(p->p_ucred)) 652 return (ENOSYS); 653 654 if (uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0])) 655 return EINVAL; 656 return ((*shmcalls[uap->which])(p, &uap->a2)); 657 } 658 659 static void 660 shmfork_myhook(p1, p2) 661 struct proc *p1, *p2; 662 { 663 struct shmmap_state *shmmap_s; 664 size_t size; 665 int i; 666 667 size = shminfo.shmseg * sizeof(struct shmmap_state); 668 shmmap_s = malloc(size, M_SHM, M_WAITOK); 669 bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size); 670 p2->p_vmspace->vm_shm = (caddr_t)shmmap_s; 671 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 672 if (shmmap_s->shmid != -1) 673 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++; 674 } 675 676 static void 677 shmexit_myhook(p) 678 struct proc *p; 679 { 680 struct shmmap_state *shmmap_s; 681 int i; 682 683 mtx_assert(&vm_mtx, MA_OWNED); /* For shm_delete_mapping. */ 684 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 685 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 686 if (shmmap_s->shmid != -1) 687 shm_delete_mapping(p, shmmap_s); 688 free((caddr_t)p->p_vmspace->vm_shm, M_SHM); 689 p->p_vmspace->vm_shm = NULL; 690 } 691 692 static void 693 shmrealloc(void) 694 { 695 int i; 696 struct shmid_ds *newsegs; 697 698 if (shmalloced >= shminfo.shmmni) 699 return; 700 701 newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK); 702 if (newsegs == NULL) 703 return; 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 free(shmsegs, M_SHM); 711 shmsegs = newsegs; 712 shmalloced = shminfo.shmmni; 713 } 714 715 static void 716 shminit() 717 { 718 int i; 719 720 shmalloced = shminfo.shmmni; 721 shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK); 722 if (shmsegs == NULL) 723 panic("cannot allocate initial memory for sysvshm"); 724 for (i = 0; i < shmalloced; i++) { 725 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 726 shmsegs[i].shm_perm.seq = 0; 727 } 728 shm_last_free = 0; 729 shm_nused = 0; 730 shm_committed = 0; 731 shmexit_hook = &shmexit_myhook; 732 shmfork_hook = &shmfork_myhook; 733 } 734 735 static int 736 shmunload() 737 { 738 739 if (shm_nused > 0) 740 return (EBUSY); 741 742 free(shmsegs, M_SHM); 743 shmexit_hook = NULL; 744 shmfork_hook = NULL; 745 return (0); 746 } 747 748 static int 749 sysctl_shmsegs(SYSCTL_HANDLER_ARGS) 750 { 751 752 return (SYSCTL_OUT(req, shmsegs, shmalloced * sizeof(shmsegs[0]))); 753 } 754 755 static int 756 sysvshm_modload(struct module *module, int cmd, void *arg) 757 { 758 int error = 0; 759 760 switch (cmd) { 761 case MOD_LOAD: 762 shminit(); 763 break; 764 case MOD_UNLOAD: 765 error = shmunload(); 766 break; 767 case MOD_SHUTDOWN: 768 break; 769 default: 770 error = EINVAL; 771 break; 772 } 773 return (error); 774 } 775 776 static moduledata_t sysvshm_mod = { 777 "sysvshm", 778 &sysvshm_modload, 779 NULL 780 }; 781 782 SYSCALL_MODULE_HELPER(shmsys, 4); 783 SYSCALL_MODULE_HELPER(shmat, 3); 784 SYSCALL_MODULE_HELPER(shmctl, 3); 785 SYSCALL_MODULE_HELPER(shmdt, 1); 786 SYSCALL_MODULE_HELPER(shmget, 3); 787 788 DECLARE_MODULE(sysvshm, sysvshm_mod, 789 SI_SUB_SYSV_SHM, SI_ORDER_FIRST); 790 MODULE_VERSION(sysvshm, 1); 791