sysv_shm.c revision 91703
1/* $FreeBSD: head/sys/kern/sysv_shm.c 91703 2002-03-05 18:57:36Z jhb $ */ 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/kernel.h> 40#include <sys/lock.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/mutex.h> 47#include <sys/stat.h> 48#include <sys/syscall.h> 49#include <sys/sysent.h> 50#include <sys/sysproto.h> 51#include <sys/jail.h> 52 53#include <vm/vm.h> 54#include <vm/vm_param.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 61static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments"); 62 63struct oshmctl_args; 64static int oshmctl __P((struct thread *td, struct oshmctl_args *uap)); 65 66static int shmget_allocate_segment __P((struct thread *td, 67 struct shmget_args *uap, int mode)); 68static int shmget_existing __P((struct thread *td, struct shmget_args *uap, 69 int mode, int segnum)); 70 71/* XXX casting to (sy_call_t *) is bogus, as usual. */ 72static sy_call_t *shmcalls[] = { 73 (sy_call_t *)shmat, (sy_call_t *)oshmctl, 74 (sy_call_t *)shmdt, (sy_call_t *)shmget, 75 (sy_call_t *)shmctl 76}; 77 78#define SHMSEG_FREE 0x0200 79#define SHMSEG_REMOVED 0x0400 80#define SHMSEG_ALLOCATED 0x0800 81#define SHMSEG_WANTED 0x1000 82 83static int shm_last_free, shm_nused, shm_committed, shmalloced; 84static struct shmid_ds *shmsegs; 85 86struct shm_handle { 87 /* vm_offset_t kva; */ 88 vm_object_t shm_object; 89}; 90 91struct shmmap_state { 92 vm_offset_t va; 93 int shmid; 94}; 95 96static void shm_deallocate_segment __P((struct shmid_ds *)); 97static int shm_find_segment_by_key __P((key_t)); 98static struct shmid_ds *shm_find_segment_by_shmid __P((int)); 99static struct shmid_ds *shm_find_segment_by_shmidx __P((int)); 100static int shm_delete_mapping __P((struct proc *p, struct shmmap_state *)); 101static void shmrealloc __P((void)); 102static void shminit __P((void)); 103static int sysvshm_modload __P((struct module *, int, void *)); 104static int shmunload __P((void)); 105static void shmexit_myhook __P((struct proc *p)); 106static void shmfork_myhook __P((struct proc *p1, struct proc *p2)); 107static 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 131struct shminfo shminfo = { 132 SHMMAX, 133 SHMMIN, 134 SHMMNI, 135 SHMSEG, 136 SHMALL 137}; 138 139static int shm_use_phys; 140 141SYSCTL_DECL(_kern_ipc); 142SYSCTL_INT(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, ""); 143SYSCTL_INT(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, ""); 144SYSCTL_INT(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0, ""); 145SYSCTL_INT(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RD, &shminfo.shmseg, 0, ""); 146SYSCTL_INT(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, ""); 147SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, 148 &shm_use_phys, 0, ""); 149SYSCTL_PROC(_kern_ipc, OID_AUTO, shmsegs, CTLFLAG_RD, 150 NULL, 0, sysctl_shmsegs, "", ""); 151 152static int 153shm_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 165static struct shmid_ds * 166shm_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 183static struct shmid_ds * 184shm_find_segment_by_shmidx(int segnum) 185{ 186 struct shmid_ds *shmseg; 187 188 if (segnum < 0 || segnum >= shmalloced) 189 return NULL; 190 shmseg = &shmsegs[segnum]; 191 if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED)) 192 != SHMSEG_ALLOCATED ) 193 return NULL; 194 return shmseg; 195} 196 197static void 198shm_deallocate_segment(shmseg) 199 struct shmid_ds *shmseg; 200{ 201 struct shm_handle *shm_handle; 202 size_t size; 203 204 GIANT_REQUIRED; 205 206 shm_handle = shmseg->shm_internal; 207 vm_object_deallocate(shm_handle->shm_object); 208 free((caddr_t)shm_handle, M_SHM); 209 shmseg->shm_internal = NULL; 210 size = round_page(shmseg->shm_segsz); 211 shm_committed -= btoc(size); 212 shm_nused--; 213 shmseg->shm_perm.mode = SHMSEG_FREE; 214} 215 216static int 217shm_delete_mapping(p, shmmap_s) 218 struct proc *p; 219 struct shmmap_state *shmmap_s; 220{ 221 struct shmid_ds *shmseg; 222 int segnum, result; 223 size_t size; 224 225 GIANT_REQUIRED; 226 227 segnum = IPCID_TO_IX(shmmap_s->shmid); 228 shmseg = &shmsegs[segnum]; 229 size = round_page(shmseg->shm_segsz); 230 result = vm_map_remove(&p->p_vmspace->vm_map, shmmap_s->va, 231 shmmap_s->va + size); 232 if (result != KERN_SUCCESS) 233 return EINVAL; 234 shmmap_s->shmid = -1; 235 shmseg->shm_dtime = time_second; 236 if ((--shmseg->shm_nattch <= 0) && 237 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { 238 shm_deallocate_segment(shmseg); 239 shm_last_free = segnum; 240 } 241 return 0; 242} 243 244#ifndef _SYS_SYSPROTO_H_ 245struct shmdt_args { 246 void *shmaddr; 247}; 248#endif 249 250/* 251 * MPSAFE 252 */ 253int 254shmdt(td, uap) 255 struct thread *td; 256 struct shmdt_args *uap; 257{ 258 struct proc *p = td->td_proc; 259 struct shmmap_state *shmmap_s; 260 int i; 261 int error = 0; 262 263 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 264 return (ENOSYS); 265 mtx_lock(&Giant); 266 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 267 if (shmmap_s == NULL) { 268 error = EINVAL; 269 goto done2; 270 } 271 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) { 272 if (shmmap_s->shmid != -1 && 273 shmmap_s->va == (vm_offset_t)uap->shmaddr) { 274 break; 275 } 276 } 277 if (i == shminfo.shmseg) { 278 error = EINVAL; 279 goto done2; 280 } 281 error = shm_delete_mapping(p, shmmap_s); 282done2: 283 mtx_unlock(&Giant); 284 return (error); 285} 286 287#ifndef _SYS_SYSPROTO_H_ 288struct shmat_args { 289 int shmid; 290 void *shmaddr; 291 int shmflg; 292}; 293#endif 294 295/* 296 * MPSAFE 297 */ 298int 299shmat(td, uap) 300 struct thread *td; 301 struct shmat_args *uap; 302{ 303 struct proc *p = td->td_proc; 304 int i, flags; 305 struct shmid_ds *shmseg; 306 struct shmmap_state *shmmap_s = NULL; 307 struct shm_handle *shm_handle; 308 vm_offset_t attach_va; 309 vm_prot_t prot; 310 vm_size_t size; 311 int rv; 312 int error = 0; 313 314 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 315 return (ENOSYS); 316 mtx_lock(&Giant); 317 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 318 if (shmmap_s == NULL) { 319 size = shminfo.shmseg * sizeof(struct shmmap_state); 320 shmmap_s = malloc(size, M_SHM, M_WAITOK); 321 for (i = 0; i < shminfo.shmseg; i++) 322 shmmap_s[i].shmid = -1; 323 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 324 } 325 shmseg = shm_find_segment_by_shmid(uap->shmid); 326 if (shmseg == NULL) { 327 error = EINVAL; 328 goto done2; 329 } 330 error = ipcperm(td, &shmseg->shm_perm, 331 (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 332 if (error) 333 goto done2; 334 for (i = 0; i < shminfo.shmseg; i++) { 335 if (shmmap_s->shmid == -1) 336 break; 337 shmmap_s++; 338 } 339 if (i >= shminfo.shmseg) { 340 error = EMFILE; 341 goto done2; 342 } 343 size = round_page(shmseg->shm_segsz); 344#ifdef VM_PROT_READ_IS_EXEC 345 prot = VM_PROT_READ | VM_PROT_EXECUTE; 346#else 347 prot = VM_PROT_READ; 348#endif 349 if ((uap->shmflg & SHM_RDONLY) == 0) 350 prot |= VM_PROT_WRITE; 351 flags = MAP_ANON | MAP_SHARED; 352 if (uap->shmaddr) { 353 flags |= MAP_FIXED; 354 if (uap->shmflg & SHM_RND) { 355 attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1); 356 } else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0) { 357 attach_va = (vm_offset_t)uap->shmaddr; 358 } else { 359 error = EINVAL; 360 goto done2; 361 } 362 } else { 363 /* 364 * This is just a hint to vm_map_find() about where to 365 * put it. 366 */ 367 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr 368 + maxtsiz + maxdsiz); 369 } 370 371 shm_handle = shmseg->shm_internal; 372 vm_object_reference(shm_handle->shm_object); 373 rv = vm_map_find(&p->p_vmspace->vm_map, shm_handle->shm_object, 374 0, &attach_va, size, (flags & MAP_FIXED)?0:1, prot, prot, 0); 375 if (rv != KERN_SUCCESS) { 376 error = ENOMEM; 377 goto done2; 378 } 379 vm_map_inherit(&p->p_vmspace->vm_map, 380 attach_va, attach_va + size, VM_INHERIT_SHARE); 381 382 shmmap_s->va = attach_va; 383 shmmap_s->shmid = uap->shmid; 384 shmseg->shm_lpid = p->p_pid; 385 shmseg->shm_atime = time_second; 386 shmseg->shm_nattch++; 387 td->td_retval[0] = attach_va; 388done2: 389 mtx_unlock(&Giant); 390 return (error); 391} 392 393struct oshmid_ds { 394 struct ipc_perm shm_perm; /* operation perms */ 395 int shm_segsz; /* size of segment (bytes) */ 396 ushort shm_cpid; /* pid, creator */ 397 ushort shm_lpid; /* pid, last operation */ 398 short shm_nattch; /* no. of current attaches */ 399 time_t shm_atime; /* last attach time */ 400 time_t shm_dtime; /* last detach time */ 401 time_t shm_ctime; /* last change time */ 402 void *shm_handle; /* internal handle for shm segment */ 403}; 404 405struct oshmctl_args { 406 int shmid; 407 int cmd; 408 struct oshmid_ds *ubuf; 409}; 410 411/* 412 * MPSAFE 413 */ 414static int 415oshmctl(td, uap) 416 struct thread *td; 417 struct oshmctl_args *uap; 418{ 419#ifdef COMPAT_43 420 int error = 0; 421 struct shmid_ds *shmseg; 422 struct oshmid_ds outbuf; 423 424 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 425 return (ENOSYS); 426 mtx_lock(&Giant); 427 shmseg = shm_find_segment_by_shmid(uap->shmid); 428 if (shmseg == NULL) { 429 error = EINVAL; 430 goto done2; 431 } 432 switch (uap->cmd) { 433 case IPC_STAT: 434 error = ipcperm(td, &shmseg->shm_perm, IPC_R); 435 if (error) 436 goto done2; 437 outbuf.shm_perm = shmseg->shm_perm; 438 outbuf.shm_segsz = shmseg->shm_segsz; 439 outbuf.shm_cpid = shmseg->shm_cpid; 440 outbuf.shm_lpid = shmseg->shm_lpid; 441 outbuf.shm_nattch = shmseg->shm_nattch; 442 outbuf.shm_atime = shmseg->shm_atime; 443 outbuf.shm_dtime = shmseg->shm_dtime; 444 outbuf.shm_ctime = shmseg->shm_ctime; 445 outbuf.shm_handle = shmseg->shm_internal; 446 error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf)); 447 if (error) 448 goto done2; 449 break; 450 default: 451 /* XXX casting to (sy_call_t *) is bogus, as usual. */ 452 error = ((sy_call_t *)shmctl)(td, uap); 453 break; 454 } 455done2: 456 mtx_unlock(&Giant); 457 return (error); 458#else 459 return EINVAL; 460#endif 461} 462 463#ifndef _SYS_SYSPROTO_H_ 464struct shmctl_args { 465 int shmid; 466 int cmd; 467 struct shmid_ds *buf; 468}; 469#endif 470 471/* 472 * MPSAFE 473 */ 474int 475shmctl(td, uap) 476 struct thread *td; 477 struct shmctl_args *uap; 478{ 479 int error = 0; 480 struct shmid_ds inbuf; 481 struct shmid_ds *shmseg; 482 483 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 484 return (ENOSYS); 485 mtx_lock(&Giant); 486 switch (uap->cmd) { 487 case IPC_INFO: 488 error = copyout( (caddr_t)&shminfo, uap->buf, sizeof( shminfo ) ); 489 if (error) 490 goto done2; 491 td->td_retval[0] = shmalloced; 492 goto done2; 493 case SHM_INFO: { 494 struct shm_info shm_info; 495 shm_info.used_ids = shm_nused; 496 shm_info.shm_rss = 0; /*XXX where to get from ? */ 497 shm_info.shm_tot = 0; /*XXX where to get from ? */ 498 shm_info.shm_swp = 0; /*XXX where to get from ? */ 499 shm_info.swap_attempts = 0; /*XXX where to get from ? */ 500 shm_info.swap_successes = 0; /*XXX where to get from ? */ 501 error = copyout( (caddr_t)&shm_info, uap->buf, sizeof( shm_info ) ); 502 if (error) 503 goto done2; 504 td->td_retval[0] = shmalloced; 505 goto done2; 506 } 507 } 508 if( (uap->cmd) == SHM_STAT ) 509 shmseg = shm_find_segment_by_shmidx(uap->shmid); 510 else 511 shmseg = shm_find_segment_by_shmid(uap->shmid); 512 if (shmseg == NULL) { 513 error = EINVAL; 514 goto done2; 515 } 516 switch (uap->cmd) { 517 case SHM_STAT: 518 case IPC_STAT: 519 error = ipcperm(td, &shmseg->shm_perm, IPC_R); 520 if (error) 521 goto done2; 522 error = copyout((caddr_t)shmseg, uap->buf, sizeof(inbuf)); 523 if (error) 524 goto done2; 525 else if( (uap->cmd) == SHM_STAT ) 526 td->td_retval[0] = IXSEQ_TO_IPCID( uap->shmid, shmseg->shm_perm ); 527 break; 528 case IPC_SET: 529 error = ipcperm(td, &shmseg->shm_perm, IPC_M); 530 if (error) 531 goto done2; 532 error = copyin(uap->buf, (caddr_t)&inbuf, sizeof(inbuf)); 533 if (error) 534 goto done2; 535 shmseg->shm_perm.uid = inbuf.shm_perm.uid; 536 shmseg->shm_perm.gid = inbuf.shm_perm.gid; 537 shmseg->shm_perm.mode = 538 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 539 (inbuf.shm_perm.mode & ACCESSPERMS); 540 shmseg->shm_ctime = time_second; 541 break; 542 case IPC_RMID: 543 error = ipcperm(td, &shmseg->shm_perm, IPC_M); 544 if (error) 545 goto done2; 546 shmseg->shm_perm.key = IPC_PRIVATE; 547 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 548 if (shmseg->shm_nattch <= 0) { 549 shm_deallocate_segment(shmseg); 550 shm_last_free = IPCID_TO_IX(uap->shmid); 551 } 552 break; 553#if 0 554 case SHM_LOCK: 555 case SHM_UNLOCK: 556#endif 557 default: 558 error = EINVAL; 559 break; 560 } 561done2: 562 mtx_unlock(&Giant); 563 return (error); 564} 565 566#ifndef _SYS_SYSPROTO_H_ 567struct shmget_args { 568 key_t key; 569 size_t size; 570 int shmflg; 571}; 572#endif 573 574static int 575shmget_existing(td, uap, mode, segnum) 576 struct thread *td; 577 struct shmget_args *uap; 578 int mode; 579 int segnum; 580{ 581 struct shmid_ds *shmseg; 582 int error; 583 584 shmseg = &shmsegs[segnum]; 585 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 586 /* 587 * This segment is in the process of being allocated. Wait 588 * until it's done, and look the key up again (in case the 589 * allocation failed or it was freed). 590 */ 591 shmseg->shm_perm.mode |= SHMSEG_WANTED; 592 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0); 593 if (error) 594 return error; 595 return EAGAIN; 596 } 597 if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL)) 598 return EEXIST; 599 error = ipcperm(td, &shmseg->shm_perm, mode); 600 if (error) 601 return error; 602 if (uap->size && uap->size > shmseg->shm_segsz) 603 return EINVAL; 604 td->td_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 605 return 0; 606} 607 608static int 609shmget_allocate_segment(td, uap, mode) 610 struct thread *td; 611 struct shmget_args *uap; 612 int mode; 613{ 614 int i, segnum, shmid, size; 615 struct ucred *cred = td->td_ucred; 616 struct shmid_ds *shmseg; 617 struct shm_handle *shm_handle; 618 619 GIANT_REQUIRED; 620 621 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax) 622 return EINVAL; 623 if (shm_nused >= shminfo.shmmni) /* Any shmids left? */ 624 return ENOSPC; 625 size = round_page(uap->size); 626 if (shm_committed + btoc(size) > shminfo.shmall) 627 return ENOMEM; 628 if (shm_last_free < 0) { 629 shmrealloc(); /* Maybe expand the shmsegs[] array. */ 630 for (i = 0; i < shmalloced; i++) 631 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 632 break; 633 if (i == shmalloced) 634 return ENOSPC; 635 segnum = i; 636 } else { 637 segnum = shm_last_free; 638 shm_last_free = -1; 639 } 640 shmseg = &shmsegs[segnum]; 641 /* 642 * In case we sleep in malloc(), mark the segment present but deleted 643 * so that noone else tries to create the same key. 644 */ 645 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 646 shmseg->shm_perm.key = uap->key; 647 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff; 648 shm_handle = (struct shm_handle *) 649 malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK); 650 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 651 652 /* 653 * We make sure that we have allocated a pager before we need 654 * to. 655 */ 656 if (shm_use_phys) { 657 shm_handle->shm_object = 658 vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0); 659 } else { 660 shm_handle->shm_object = 661 vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0); 662 } 663 vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING); 664 vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT); 665 666 shmseg->shm_internal = shm_handle; 667 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 668 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 669 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 670 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 671 shmseg->shm_segsz = uap->size; 672 shmseg->shm_cpid = td->td_proc->p_pid; 673 shmseg->shm_lpid = shmseg->shm_nattch = 0; 674 shmseg->shm_atime = shmseg->shm_dtime = 0; 675 shmseg->shm_ctime = time_second; 676 shm_committed += btoc(size); 677 shm_nused++; 678 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 679 /* 680 * Somebody else wanted this key while we were asleep. Wake 681 * them up now. 682 */ 683 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 684 wakeup((caddr_t)shmseg); 685 } 686 td->td_retval[0] = shmid; 687 return 0; 688} 689 690/* 691 * MPSAFE 692 */ 693int 694shmget(td, uap) 695 struct thread *td; 696 struct shmget_args *uap; 697{ 698 int segnum, mode; 699 int error; 700 701 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 702 return (ENOSYS); 703 mtx_lock(&Giant); 704 mode = uap->shmflg & ACCESSPERMS; 705 if (uap->key != IPC_PRIVATE) { 706 again: 707 segnum = shm_find_segment_by_key(uap->key); 708 if (segnum >= 0) { 709 error = shmget_existing(td, uap, mode, segnum); 710 if (error == EAGAIN) 711 goto again; 712 goto done2; 713 } 714 if ((uap->shmflg & IPC_CREAT) == 0) { 715 error = ENOENT; 716 goto done2; 717 } 718 } 719 error = shmget_allocate_segment(td, uap, mode); 720done2: 721 mtx_unlock(&Giant); 722 return (error); 723} 724 725/* 726 * MPSAFE 727 */ 728int 729shmsys(td, uap) 730 struct thread *td; 731 /* XXX actually varargs. */ 732 struct shmsys_args /* { 733 u_int which; 734 int a2; 735 int a3; 736 int a4; 737 } */ *uap; 738{ 739 int error; 740 741 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 742 return (ENOSYS); 743 if (uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0])) 744 return (EINVAL); 745 mtx_lock(&Giant); 746 error = (*shmcalls[uap->which])(td, &uap->a2); 747 mtx_unlock(&Giant); 748 return (error); 749} 750 751static void 752shmfork_myhook(p1, p2) 753 struct proc *p1, *p2; 754{ 755 struct shmmap_state *shmmap_s; 756 size_t size; 757 int i; 758 759 size = shminfo.shmseg * sizeof(struct shmmap_state); 760 shmmap_s = malloc(size, M_SHM, M_WAITOK); 761 bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size); 762 p2->p_vmspace->vm_shm = (caddr_t)shmmap_s; 763 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 764 if (shmmap_s->shmid != -1) 765 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++; 766} 767 768static void 769shmexit_myhook(p) 770 struct proc *p; 771{ 772 struct shmmap_state *shmmap_s; 773 int i; 774 775 GIANT_REQUIRED; 776 777 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 778 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 779 if (shmmap_s->shmid != -1) 780 shm_delete_mapping(p, shmmap_s); 781 free((caddr_t)p->p_vmspace->vm_shm, M_SHM); 782 p->p_vmspace->vm_shm = NULL; 783} 784 785static void 786shmrealloc(void) 787{ 788 int i; 789 struct shmid_ds *newsegs; 790 791 if (shmalloced >= shminfo.shmmni) 792 return; 793 794 newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK); 795 if (newsegs == NULL) 796 return; 797 for (i = 0; i < shmalloced; i++) 798 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0])); 799 for (; i < shminfo.shmmni; i++) { 800 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 801 shmsegs[i].shm_perm.seq = 0; 802 } 803 free(shmsegs, M_SHM); 804 shmsegs = newsegs; 805 shmalloced = shminfo.shmmni; 806} 807 808static void 809shminit() 810{ 811 int i; 812 813 TUNABLE_INT_FETCH("kern.ipc.shmmaxpgs", &shminfo.shmall); 814 shminfo.shmmax = shminfo.shmall * PAGE_SIZE; 815 TUNABLE_INT_FETCH("kern.ipc.shmmin", &shminfo.shmmin); 816 TUNABLE_INT_FETCH("kern.ipc.shmmni", &shminfo.shmmni); 817 TUNABLE_INT_FETCH("kern.ipc.shmseg", &shminfo.shmseg); 818 TUNABLE_INT_FETCH("kern.ipc.shm_use_phys", &shm_use_phys); 819 820 shmalloced = shminfo.shmmni; 821 shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK); 822 if (shmsegs == NULL) 823 panic("cannot allocate initial memory for sysvshm"); 824 for (i = 0; i < shmalloced; i++) { 825 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 826 shmsegs[i].shm_perm.seq = 0; 827 } 828 shm_last_free = 0; 829 shm_nused = 0; 830 shm_committed = 0; 831 shmexit_hook = &shmexit_myhook; 832 shmfork_hook = &shmfork_myhook; 833} 834 835static int 836shmunload() 837{ 838 839 if (shm_nused > 0) 840 return (EBUSY); 841 842 free(shmsegs, M_SHM); 843 shmexit_hook = NULL; 844 shmfork_hook = NULL; 845 return (0); 846} 847 848static int 849sysctl_shmsegs(SYSCTL_HANDLER_ARGS) 850{ 851 852 return (SYSCTL_OUT(req, shmsegs, shmalloced * sizeof(shmsegs[0]))); 853} 854 855static int 856sysvshm_modload(struct module *module, int cmd, void *arg) 857{ 858 int error = 0; 859 860 switch (cmd) { 861 case MOD_LOAD: 862 shminit(); 863 break; 864 case MOD_UNLOAD: 865 error = shmunload(); 866 break; 867 case MOD_SHUTDOWN: 868 break; 869 default: 870 error = EINVAL; 871 break; 872 } 873 return (error); 874} 875 876static moduledata_t sysvshm_mod = { 877 "sysvshm", 878 &sysvshm_modload, 879 NULL 880}; 881 882SYSCALL_MODULE_HELPER(shmsys); 883SYSCALL_MODULE_HELPER(shmat); 884SYSCALL_MODULE_HELPER(shmctl); 885SYSCALL_MODULE_HELPER(shmdt); 886SYSCALL_MODULE_HELPER(shmget); 887 888DECLARE_MODULE(sysvshm, sysvshm_mod, 889 SI_SUB_SYSV_SHM, SI_ORDER_FIRST); 890MODULE_VERSION(sysvshm, 1); 891