sysv_shm.c revision 91406
1/* $FreeBSD: head/sys/kern/sysv_shm.c 91406 2002-02-27 18:32:23Z 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 mtx_lock(&Giant); 264 if (!jail_sysvipc_allowed && jailed(p->p_ucred)) { 265 error = ENOSYS; 266 goto done2; 267 } 268 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 269 if (shmmap_s == NULL) { 270 error = EINVAL; 271 goto done2; 272 } 273 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) { 274 if (shmmap_s->shmid != -1 && 275 shmmap_s->va == (vm_offset_t)uap->shmaddr) { 276 break; 277 } 278 } 279 if (i == shminfo.shmseg) { 280 error = EINVAL; 281 goto done2; 282 } 283 error = shm_delete_mapping(p, shmmap_s); 284done2: 285 mtx_unlock(&Giant); 286 return (error); 287} 288 289#ifndef _SYS_SYSPROTO_H_ 290struct shmat_args { 291 int shmid; 292 void *shmaddr; 293 int shmflg; 294}; 295#endif 296 297/* 298 * MPSAFE 299 */ 300int 301shmat(td, uap) 302 struct thread *td; 303 struct shmat_args *uap; 304{ 305 struct proc *p = td->td_proc; 306 int i, flags; 307 struct shmid_ds *shmseg; 308 struct shmmap_state *shmmap_s = NULL; 309 struct shm_handle *shm_handle; 310 vm_offset_t attach_va; 311 vm_prot_t prot; 312 vm_size_t size; 313 int rv; 314 int error = 0; 315 316 mtx_lock(&Giant); 317 if (!jail_sysvipc_allowed && jailed(p->p_ucred)) { 318 error = ENOSYS; 319 goto done2; 320 } 321 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 322 if (shmmap_s == NULL) { 323 size = shminfo.shmseg * sizeof(struct shmmap_state); 324 shmmap_s = malloc(size, M_SHM, M_WAITOK); 325 for (i = 0; i < shminfo.shmseg; i++) 326 shmmap_s[i].shmid = -1; 327 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 328 } 329 shmseg = shm_find_segment_by_shmid(uap->shmid); 330 if (shmseg == NULL) { 331 error = EINVAL; 332 goto done2; 333 } 334 error = ipcperm(td, &shmseg->shm_perm, 335 (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 336 if (error) 337 goto done2; 338 for (i = 0; i < shminfo.shmseg; i++) { 339 if (shmmap_s->shmid == -1) 340 break; 341 shmmap_s++; 342 } 343 if (i >= shminfo.shmseg) { 344 error = EMFILE; 345 goto done2; 346 } 347 size = round_page(shmseg->shm_segsz); 348#ifdef VM_PROT_READ_IS_EXEC 349 prot = VM_PROT_READ | VM_PROT_EXECUTE; 350#else 351 prot = VM_PROT_READ; 352#endif 353 if ((uap->shmflg & SHM_RDONLY) == 0) 354 prot |= VM_PROT_WRITE; 355 flags = MAP_ANON | MAP_SHARED; 356 if (uap->shmaddr) { 357 flags |= MAP_FIXED; 358 if (uap->shmflg & SHM_RND) { 359 attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1); 360 } else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0) { 361 attach_va = (vm_offset_t)uap->shmaddr; 362 } else { 363 error = EINVAL; 364 goto done2; 365 } 366 } else { 367 /* 368 * This is just a hint to vm_map_find() about where to 369 * put it. 370 */ 371 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr 372 + maxtsiz + maxdsiz); 373 } 374 375 shm_handle = shmseg->shm_internal; 376 vm_object_reference(shm_handle->shm_object); 377 rv = vm_map_find(&p->p_vmspace->vm_map, shm_handle->shm_object, 378 0, &attach_va, size, (flags & MAP_FIXED)?0:1, prot, prot, 0); 379 if (rv != KERN_SUCCESS) { 380 error = ENOMEM; 381 goto done2; 382 } 383 vm_map_inherit(&p->p_vmspace->vm_map, 384 attach_va, attach_va + size, VM_INHERIT_SHARE); 385 386 shmmap_s->va = attach_va; 387 shmmap_s->shmid = uap->shmid; 388 shmseg->shm_lpid = p->p_pid; 389 shmseg->shm_atime = time_second; 390 shmseg->shm_nattch++; 391 td->td_retval[0] = attach_va; 392done2: 393 mtx_unlock(&Giant); 394 return (error); 395} 396 397struct oshmid_ds { 398 struct ipc_perm shm_perm; /* operation perms */ 399 int shm_segsz; /* size of segment (bytes) */ 400 ushort shm_cpid; /* pid, creator */ 401 ushort shm_lpid; /* pid, last operation */ 402 short shm_nattch; /* no. of current attaches */ 403 time_t shm_atime; /* last attach time */ 404 time_t shm_dtime; /* last detach time */ 405 time_t shm_ctime; /* last change time */ 406 void *shm_handle; /* internal handle for shm segment */ 407}; 408 409struct oshmctl_args { 410 int shmid; 411 int cmd; 412 struct oshmid_ds *ubuf; 413}; 414 415/* 416 * MPSAFE 417 */ 418static int 419oshmctl(td, uap) 420 struct thread *td; 421 struct oshmctl_args *uap; 422{ 423#ifdef COMPAT_43 424 int error = 0; 425 struct shmid_ds *shmseg; 426 struct oshmid_ds outbuf; 427 428 mtx_lock(&Giant); 429 if (!jail_sysvipc_allowed && jailed(td->td_proc->p_ucred)) { 430 error = ENOSYS; 431 goto done2; 432 } 433 shmseg = shm_find_segment_by_shmid(uap->shmid); 434 if (shmseg == NULL) { 435 error = EINVAL; 436 goto done2; 437 } 438 switch (uap->cmd) { 439 case IPC_STAT: 440 error = ipcperm(td, &shmseg->shm_perm, IPC_R); 441 if (error) 442 goto done2; 443 outbuf.shm_perm = shmseg->shm_perm; 444 outbuf.shm_segsz = shmseg->shm_segsz; 445 outbuf.shm_cpid = shmseg->shm_cpid; 446 outbuf.shm_lpid = shmseg->shm_lpid; 447 outbuf.shm_nattch = shmseg->shm_nattch; 448 outbuf.shm_atime = shmseg->shm_atime; 449 outbuf.shm_dtime = shmseg->shm_dtime; 450 outbuf.shm_ctime = shmseg->shm_ctime; 451 outbuf.shm_handle = shmseg->shm_internal; 452 error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf)); 453 if (error) 454 goto done2; 455 break; 456 default: 457 /* XXX casting to (sy_call_t *) is bogus, as usual. */ 458 error = ((sy_call_t *)shmctl)(td, uap); 459 break; 460 } 461done2: 462 mtx_unlock(&Giant); 463 return (error); 464#else 465 return EINVAL; 466#endif 467} 468 469#ifndef _SYS_SYSPROTO_H_ 470struct shmctl_args { 471 int shmid; 472 int cmd; 473 struct shmid_ds *buf; 474}; 475#endif 476 477/* 478 * MPSAFE 479 */ 480int 481shmctl(td, uap) 482 struct thread *td; 483 struct shmctl_args *uap; 484{ 485 int error = 0; 486 struct shmid_ds inbuf; 487 struct shmid_ds *shmseg; 488 489 mtx_lock(&Giant); 490 if (!jail_sysvipc_allowed && jailed(td->td_proc->p_ucred)) { 491 error = ENOSYS; 492 goto done2; 493 } 494 switch (uap->cmd) { 495 case IPC_INFO: 496 error = copyout( (caddr_t)&shminfo, uap->buf, sizeof( shminfo ) ); 497 if (error) 498 goto done2; 499 td->td_retval[0] = shmalloced; 500 goto done2; 501 case SHM_INFO: { 502 struct shm_info shm_info; 503 shm_info.used_ids = shm_nused; 504 shm_info.shm_rss = 0; /*XXX where to get from ? */ 505 shm_info.shm_tot = 0; /*XXX where to get from ? */ 506 shm_info.shm_swp = 0; /*XXX where to get from ? */ 507 shm_info.swap_attempts = 0; /*XXX where to get from ? */ 508 shm_info.swap_successes = 0; /*XXX where to get from ? */ 509 error = copyout( (caddr_t)&shm_info, uap->buf, sizeof( shm_info ) ); 510 if (error) 511 goto done2; 512 td->td_retval[0] = shmalloced; 513 goto done2; 514 } 515 } 516 if( (uap->cmd) == SHM_STAT ) 517 shmseg = shm_find_segment_by_shmidx(uap->shmid); 518 else 519 shmseg = shm_find_segment_by_shmid(uap->shmid); 520 if (shmseg == NULL) { 521 error = EINVAL; 522 goto done2; 523 } 524 switch (uap->cmd) { 525 case SHM_STAT: 526 case IPC_STAT: 527 error = ipcperm(td, &shmseg->shm_perm, IPC_R); 528 if (error) 529 goto done2; 530 error = copyout((caddr_t)shmseg, uap->buf, sizeof(inbuf)); 531 if (error) 532 goto done2; 533 else if( (uap->cmd) == SHM_STAT ) 534 td->td_retval[0] = IXSEQ_TO_IPCID( uap->shmid, shmseg->shm_perm ); 535 break; 536 case IPC_SET: 537 error = ipcperm(td, &shmseg->shm_perm, IPC_M); 538 if (error) 539 goto done2; 540 error = copyin(uap->buf, (caddr_t)&inbuf, sizeof(inbuf)); 541 if (error) 542 goto done2; 543 shmseg->shm_perm.uid = inbuf.shm_perm.uid; 544 shmseg->shm_perm.gid = inbuf.shm_perm.gid; 545 shmseg->shm_perm.mode = 546 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 547 (inbuf.shm_perm.mode & ACCESSPERMS); 548 shmseg->shm_ctime = time_second; 549 break; 550 case IPC_RMID: 551 error = ipcperm(td, &shmseg->shm_perm, IPC_M); 552 if (error) 553 goto done2; 554 shmseg->shm_perm.key = IPC_PRIVATE; 555 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 556 if (shmseg->shm_nattch <= 0) { 557 shm_deallocate_segment(shmseg); 558 shm_last_free = IPCID_TO_IX(uap->shmid); 559 } 560 break; 561#if 0 562 case SHM_LOCK: 563 case SHM_UNLOCK: 564#endif 565 default: 566 error = EINVAL; 567 break; 568 } 569done2: 570 mtx_unlock(&Giant); 571 return (error); 572} 573 574#ifndef _SYS_SYSPROTO_H_ 575struct shmget_args { 576 key_t key; 577 size_t size; 578 int shmflg; 579}; 580#endif 581 582static int 583shmget_existing(td, uap, mode, segnum) 584 struct thread *td; 585 struct shmget_args *uap; 586 int mode; 587 int segnum; 588{ 589 struct shmid_ds *shmseg; 590 int error; 591 592 shmseg = &shmsegs[segnum]; 593 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 594 /* 595 * This segment is in the process of being allocated. Wait 596 * until it's done, and look the key up again (in case the 597 * allocation failed or it was freed). 598 */ 599 shmseg->shm_perm.mode |= SHMSEG_WANTED; 600 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0); 601 if (error) 602 return error; 603 return EAGAIN; 604 } 605 if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL)) 606 return EEXIST; 607 error = ipcperm(td, &shmseg->shm_perm, mode); 608 if (error) 609 return error; 610 if (uap->size && uap->size > shmseg->shm_segsz) 611 return EINVAL; 612 td->td_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 613 return 0; 614} 615 616static int 617shmget_allocate_segment(td, uap, mode) 618 struct thread *td; 619 struct shmget_args *uap; 620 int mode; 621{ 622 int i, segnum, shmid, size; 623 struct ucred *cred = td->td_ucred; 624 struct shmid_ds *shmseg; 625 struct shm_handle *shm_handle; 626 627 GIANT_REQUIRED; 628 629 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax) 630 return EINVAL; 631 if (shm_nused >= shminfo.shmmni) /* Any shmids left? */ 632 return ENOSPC; 633 size = round_page(uap->size); 634 if (shm_committed + btoc(size) > shminfo.shmall) 635 return ENOMEM; 636 if (shm_last_free < 0) { 637 shmrealloc(); /* Maybe expand the shmsegs[] array. */ 638 for (i = 0; i < shmalloced; i++) 639 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 640 break; 641 if (i == shmalloced) 642 return ENOSPC; 643 segnum = i; 644 } else { 645 segnum = shm_last_free; 646 shm_last_free = -1; 647 } 648 shmseg = &shmsegs[segnum]; 649 /* 650 * In case we sleep in malloc(), mark the segment present but deleted 651 * so that noone else tries to create the same key. 652 */ 653 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 654 shmseg->shm_perm.key = uap->key; 655 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff; 656 shm_handle = (struct shm_handle *) 657 malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK); 658 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 659 660 /* 661 * We make sure that we have allocated a pager before we need 662 * to. 663 */ 664 if (shm_use_phys) { 665 shm_handle->shm_object = 666 vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0); 667 } else { 668 shm_handle->shm_object = 669 vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0); 670 } 671 vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING); 672 vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT); 673 674 shmseg->shm_internal = shm_handle; 675 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 676 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 677 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 678 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 679 shmseg->shm_segsz = uap->size; 680 shmseg->shm_cpid = td->td_proc->p_pid; 681 shmseg->shm_lpid = shmseg->shm_nattch = 0; 682 shmseg->shm_atime = shmseg->shm_dtime = 0; 683 shmseg->shm_ctime = time_second; 684 shm_committed += btoc(size); 685 shm_nused++; 686 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 687 /* 688 * Somebody else wanted this key while we were asleep. Wake 689 * them up now. 690 */ 691 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 692 wakeup((caddr_t)shmseg); 693 } 694 td->td_retval[0] = shmid; 695 return 0; 696} 697 698/* 699 * MPSAFE 700 */ 701int 702shmget(td, uap) 703 struct thread *td; 704 struct shmget_args *uap; 705{ 706 int segnum, mode; 707 int error; 708 709 mtx_lock(&Giant); 710 if (!jail_sysvipc_allowed && jailed(td->td_proc->p_ucred)) { 711 error = ENOSYS; 712 goto done2; 713 } 714 mode = uap->shmflg & ACCESSPERMS; 715 if (uap->key != IPC_PRIVATE) { 716 again: 717 segnum = shm_find_segment_by_key(uap->key); 718 if (segnum >= 0) { 719 error = shmget_existing(td, uap, mode, segnum); 720 if (error == EAGAIN) 721 goto again; 722 goto done2; 723 } 724 if ((uap->shmflg & IPC_CREAT) == 0) { 725 error = ENOENT; 726 goto done2; 727 } 728 } 729 error = shmget_allocate_segment(td, uap, mode); 730done2: 731 mtx_unlock(&Giant); 732 return (error); 733} 734 735/* 736 * MPSAFE 737 */ 738int 739shmsys(td, uap) 740 struct thread *td; 741 /* XXX actually varargs. */ 742 struct shmsys_args /* { 743 u_int which; 744 int a2; 745 int a3; 746 int a4; 747 } */ *uap; 748{ 749 int error; 750 751 mtx_lock(&Giant); 752 if (!jail_sysvipc_allowed && jailed(td->td_proc->p_ucred)) { 753 error = ENOSYS; 754 goto done2; 755 } 756 if (uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0])) { 757 error = EINVAL; 758 goto done2; 759 } 760 error = (*shmcalls[uap->which])(td, &uap->a2); 761done2: 762 mtx_unlock(&Giant); 763 return (error); 764} 765 766static void 767shmfork_myhook(p1, p2) 768 struct proc *p1, *p2; 769{ 770 struct shmmap_state *shmmap_s; 771 size_t size; 772 int i; 773 774 size = shminfo.shmseg * sizeof(struct shmmap_state); 775 shmmap_s = malloc(size, M_SHM, M_WAITOK); 776 bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size); 777 p2->p_vmspace->vm_shm = (caddr_t)shmmap_s; 778 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 779 if (shmmap_s->shmid != -1) 780 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++; 781} 782 783static void 784shmexit_myhook(p) 785 struct proc *p; 786{ 787 struct shmmap_state *shmmap_s; 788 int i; 789 790 GIANT_REQUIRED; 791 792 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 793 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 794 if (shmmap_s->shmid != -1) 795 shm_delete_mapping(p, shmmap_s); 796 free((caddr_t)p->p_vmspace->vm_shm, M_SHM); 797 p->p_vmspace->vm_shm = NULL; 798} 799 800static void 801shmrealloc(void) 802{ 803 int i; 804 struct shmid_ds *newsegs; 805 806 if (shmalloced >= shminfo.shmmni) 807 return; 808 809 newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK); 810 if (newsegs == NULL) 811 return; 812 for (i = 0; i < shmalloced; i++) 813 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0])); 814 for (; i < shminfo.shmmni; i++) { 815 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 816 shmsegs[i].shm_perm.seq = 0; 817 } 818 free(shmsegs, M_SHM); 819 shmsegs = newsegs; 820 shmalloced = shminfo.shmmni; 821} 822 823static void 824shminit() 825{ 826 int i; 827 828 TUNABLE_INT_FETCH("kern.ipc.shmmaxpgs", &shminfo.shmall); 829 shminfo.shmmax = shminfo.shmall * PAGE_SIZE; 830 TUNABLE_INT_FETCH("kern.ipc.shmmin", &shminfo.shmmin); 831 TUNABLE_INT_FETCH("kern.ipc.shmmni", &shminfo.shmmni); 832 TUNABLE_INT_FETCH("kern.ipc.shmseg", &shminfo.shmseg); 833 TUNABLE_INT_FETCH("kern.ipc.shm_use_phys", &shm_use_phys); 834 835 shmalloced = shminfo.shmmni; 836 shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK); 837 if (shmsegs == NULL) 838 panic("cannot allocate initial memory for sysvshm"); 839 for (i = 0; i < shmalloced; i++) { 840 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 841 shmsegs[i].shm_perm.seq = 0; 842 } 843 shm_last_free = 0; 844 shm_nused = 0; 845 shm_committed = 0; 846 shmexit_hook = &shmexit_myhook; 847 shmfork_hook = &shmfork_myhook; 848} 849 850static int 851shmunload() 852{ 853 854 if (shm_nused > 0) 855 return (EBUSY); 856 857 free(shmsegs, M_SHM); 858 shmexit_hook = NULL; 859 shmfork_hook = NULL; 860 return (0); 861} 862 863static int 864sysctl_shmsegs(SYSCTL_HANDLER_ARGS) 865{ 866 867 return (SYSCTL_OUT(req, shmsegs, shmalloced * sizeof(shmsegs[0]))); 868} 869 870static int 871sysvshm_modload(struct module *module, int cmd, void *arg) 872{ 873 int error = 0; 874 875 switch (cmd) { 876 case MOD_LOAD: 877 shminit(); 878 break; 879 case MOD_UNLOAD: 880 error = shmunload(); 881 break; 882 case MOD_SHUTDOWN: 883 break; 884 default: 885 error = EINVAL; 886 break; 887 } 888 return (error); 889} 890 891static moduledata_t sysvshm_mod = { 892 "sysvshm", 893 &sysvshm_modload, 894 NULL 895}; 896 897SYSCALL_MODULE_HELPER(shmsys); 898SYSCALL_MODULE_HELPER(shmat); 899SYSCALL_MODULE_HELPER(shmctl); 900SYSCALL_MODULE_HELPER(shmdt); 901SYSCALL_MODULE_HELPER(shmget); 902 903DECLARE_MODULE(sysvshm, sysvshm_mod, 904 SI_SUB_SYSV_SHM, SI_ORDER_FIRST); 905MODULE_VERSION(sysvshm, 1); 906