sysv_shm.c revision 116182
1/* $NetBSD: sysv_shm.c,v 1.23 1994/07/04 23:25:12 glass Exp $ */ 2/* 3 * Copyright (c) 1994 Adam Glass and Charles Hannum. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by Adam Glass and Charles 16 * Hannum. 17 * 4. The names of the authors may not be used to endorse or promote products 18 * derived from this software without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR 21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 23 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, 24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 29 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32#include <sys/cdefs.h> 33__FBSDID("$FreeBSD: head/sys/kern/sysv_shm.c 116182 2003-06-11 00:56:59Z obrien $"); 34 35#include "opt_compat.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/syscallsubr.h> 51#include <sys/sysent.h> 52#include <sys/sysproto.h> 53#include <sys/jail.h> 54 55#include <vm/vm.h> 56#include <vm/vm_param.h> 57#include <vm/pmap.h> 58#include <vm/vm_object.h> 59#include <vm/vm_map.h> 60#include <vm/vm_page.h> 61#include <vm/vm_pager.h> 62 63static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments"); 64 65struct oshmctl_args; 66static int oshmctl(struct thread *td, struct oshmctl_args *uap); 67 68static int shmget_allocate_segment(struct thread *td, 69 struct shmget_args *uap, int mode); 70static int shmget_existing(struct thread *td, struct shmget_args *uap, 71 int mode, int segnum); 72 73/* XXX casting to (sy_call_t *) is bogus, as usual. */ 74static sy_call_t *shmcalls[] = { 75 (sy_call_t *)shmat, (sy_call_t *)oshmctl, 76 (sy_call_t *)shmdt, (sy_call_t *)shmget, 77 (sy_call_t *)shmctl 78}; 79 80#define SHMSEG_FREE 0x0200 81#define SHMSEG_REMOVED 0x0400 82#define SHMSEG_ALLOCATED 0x0800 83#define SHMSEG_WANTED 0x1000 84 85static int shm_last_free, shm_nused, shm_committed, shmalloced; 86static struct shmid_ds *shmsegs; 87 88struct shm_handle { 89 /* vm_offset_t kva; */ 90 vm_object_t shm_object; 91}; 92 93struct shmmap_state { 94 vm_offset_t va; 95 int shmid; 96}; 97 98static void shm_deallocate_segment(struct shmid_ds *); 99static int shm_find_segment_by_key(key_t); 100static struct shmid_ds *shm_find_segment_by_shmid(int, int); 101static struct shmid_ds *shm_find_segment_by_shmidx(int, int); 102static int shm_delete_mapping(struct vmspace *vm, struct shmmap_state *); 103static void shmrealloc(void); 104static void shminit(void); 105static int sysvshm_modload(struct module *, int, void *); 106static int shmunload(void); 107static void shmexit_myhook(struct vmspace *vm); 108static void shmfork_myhook(struct proc *p1, struct proc *p2); 109static int sysctl_shmsegs(SYSCTL_HANDLER_ARGS); 110 111/* 112 * Tuneable values. 113 */ 114#ifndef SHMMAXPGS 115#define SHMMAXPGS 8192 /* Note: sysv shared memory is swap backed. */ 116#endif 117#ifndef SHMMAX 118#define SHMMAX (SHMMAXPGS*PAGE_SIZE) 119#endif 120#ifndef SHMMIN 121#define SHMMIN 1 122#endif 123#ifndef SHMMNI 124#define SHMMNI 192 125#endif 126#ifndef SHMSEG 127#define SHMSEG 128 128#endif 129#ifndef SHMALL 130#define SHMALL (SHMMAXPGS) 131#endif 132 133struct shminfo shminfo = { 134 SHMMAX, 135 SHMMIN, 136 SHMMNI, 137 SHMSEG, 138 SHMALL 139}; 140 141static int shm_use_phys; 142 143SYSCTL_DECL(_kern_ipc); 144SYSCTL_INT(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, ""); 145SYSCTL_INT(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, ""); 146SYSCTL_INT(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0, ""); 147SYSCTL_INT(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RD, &shminfo.shmseg, 0, ""); 148SYSCTL_INT(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, ""); 149SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, 150 &shm_use_phys, 0, ""); 151SYSCTL_PROC(_kern_ipc, OID_AUTO, shmsegs, CTLFLAG_RD, 152 NULL, 0, sysctl_shmsegs, "", ""); 153 154static int 155shm_find_segment_by_key(key) 156 key_t key; 157{ 158 int i; 159 160 for (i = 0; i < shmalloced; i++) 161 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) && 162 shmsegs[i].shm_perm.key == key) 163 return (i); 164 return (-1); 165} 166 167static struct shmid_ds * 168shm_find_segment_by_shmid(int shmid, int wantrem) 169{ 170 int segnum; 171 struct shmid_ds *shmseg; 172 173 segnum = IPCID_TO_IX(shmid); 174 if (segnum < 0 || segnum >= shmalloced) 175 return (NULL); 176 shmseg = &shmsegs[segnum]; 177 if (!((shmseg->shm_perm.mode & SHMSEG_ALLOCATED) || 178 (wantrem && !(shmseg->shm_perm.mode & SHMSEG_REMOVED))) || 179 shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid)) 180 return (NULL); 181 return (shmseg); 182} 183 184static struct shmid_ds * 185shm_find_segment_by_shmidx(int segnum, int wantrem) 186{ 187 struct shmid_ds *shmseg; 188 189 if (segnum < 0 || segnum >= shmalloced) 190 return (NULL); 191 shmseg = &shmsegs[segnum]; 192 if (!((shmseg->shm_perm.mode & SHMSEG_ALLOCATED) || 193 (wantrem && !(shmseg->shm_perm.mode & SHMSEG_REMOVED)))) 194 return (NULL); 195 return (shmseg); 196} 197 198static void 199shm_deallocate_segment(shmseg) 200 struct shmid_ds *shmseg; 201{ 202 struct shm_handle *shm_handle; 203 size_t size; 204 205 GIANT_REQUIRED; 206 207 shm_handle = shmseg->shm_internal; 208 vm_object_deallocate(shm_handle->shm_object); 209 free(shm_handle, M_SHM); 210 shmseg->shm_internal = NULL; 211 size = round_page(shmseg->shm_segsz); 212 shm_committed -= btoc(size); 213 shm_nused--; 214 shmseg->shm_perm.mode = SHMSEG_FREE; 215} 216 217static int 218shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s) 219{ 220 struct shmid_ds *shmseg; 221 int segnum, result; 222 size_t size; 223 224 GIANT_REQUIRED; 225 226 segnum = IPCID_TO_IX(shmmap_s->shmid); 227 shmseg = &shmsegs[segnum]; 228 size = round_page(shmseg->shm_segsz); 229 result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size); 230 if (result != KERN_SUCCESS) 231 return (EINVAL); 232 shmmap_s->shmid = -1; 233 shmseg->shm_dtime = time_second; 234 if ((--shmseg->shm_nattch <= 0) && 235 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { 236 shm_deallocate_segment(shmseg); 237 shm_last_free = segnum; 238 } 239 return (0); 240} 241 242#ifndef _SYS_SYSPROTO_H_ 243struct shmdt_args { 244 const void *shmaddr; 245}; 246#endif 247 248/* 249 * MPSAFE 250 */ 251int 252shmdt(td, uap) 253 struct thread *td; 254 struct shmdt_args *uap; 255{ 256 struct proc *p = td->td_proc; 257 struct shmmap_state *shmmap_s; 258 int i; 259 int error = 0; 260 261 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 262 return (ENOSYS); 263 mtx_lock(&Giant); 264 shmmap_s = p->p_vmspace->vm_shm; 265 if (shmmap_s == NULL) { 266 error = EINVAL; 267 goto done2; 268 } 269 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) { 270 if (shmmap_s->shmid != -1 && 271 shmmap_s->va == (vm_offset_t)uap->shmaddr) { 272 break; 273 } 274 } 275 if (i == shminfo.shmseg) { 276 error = EINVAL; 277 goto done2; 278 } 279 error = shm_delete_mapping(p->p_vmspace, shmmap_s); 280done2: 281 mtx_unlock(&Giant); 282 return (error); 283} 284 285#ifndef _SYS_SYSPROTO_H_ 286struct shmat_args { 287 int shmid; 288 const void *shmaddr; 289 int shmflg; 290}; 291#endif 292 293/* 294 * MPSAFE 295 */ 296int 297kern_shmat(td, shmid, shmaddr, shmflg, wantrem) 298 struct thread *td; 299 int shmid; 300 const void *shmaddr; 301 int shmflg; 302 int wantrem; 303{ 304 struct proc *p = td->td_proc; 305 int i, flags; 306 struct shmid_ds *shmseg; 307 struct shmmap_state *shmmap_s = NULL; 308 struct shm_handle *shm_handle; 309 vm_offset_t attach_va; 310 vm_prot_t prot; 311 vm_size_t size; 312 int rv; 313 int error = 0; 314 315 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 316 return (ENOSYS); 317 mtx_lock(&Giant); 318 shmmap_s = p->p_vmspace->vm_shm; 319 if (shmmap_s == NULL) { 320 size = shminfo.shmseg * sizeof(struct shmmap_state); 321 shmmap_s = malloc(size, M_SHM, M_WAITOK); 322 for (i = 0; i < shminfo.shmseg; i++) 323 shmmap_s[i].shmid = -1; 324 p->p_vmspace->vm_shm = shmmap_s; 325 } 326 shmseg = shm_find_segment_by_shmid(shmid, wantrem); 327 if (shmseg == NULL) { 328 error = EINVAL; 329 goto done2; 330 } 331 error = ipcperm(td, &shmseg->shm_perm, 332 (shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 333 if (error) 334 goto done2; 335 for (i = 0; i < shminfo.shmseg; i++) { 336 if (shmmap_s->shmid == -1) 337 break; 338 shmmap_s++; 339 } 340 if (i >= shminfo.shmseg) { 341 error = EMFILE; 342 goto done2; 343 } 344 size = round_page(shmseg->shm_segsz); 345#ifdef VM_PROT_READ_IS_EXEC 346 prot = VM_PROT_READ | VM_PROT_EXECUTE; 347#else 348 prot = VM_PROT_READ; 349#endif 350 if ((shmflg & SHM_RDONLY) == 0) 351 prot |= VM_PROT_WRITE; 352 flags = MAP_ANON | MAP_SHARED; 353 if (shmaddr) { 354 flags |= MAP_FIXED; 355 if (shmflg & SHM_RND) { 356 attach_va = (vm_offset_t)shmaddr & ~(SHMLBA-1); 357 } else if (((vm_offset_t)shmaddr & (SHMLBA-1)) == 0) { 358 attach_va = (vm_offset_t)shmaddr; 359 } else { 360 error = EINVAL; 361 goto done2; 362 } 363 } else { 364 /* 365 * This is just a hint to vm_map_find() about where to 366 * put it. 367 */ 368 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr 369 + maxtsiz + maxdsiz); 370 } 371 372 shm_handle = shmseg->shm_internal; 373 vm_object_reference(shm_handle->shm_object); 374 rv = vm_map_find(&p->p_vmspace->vm_map, shm_handle->shm_object, 375 0, &attach_va, size, (flags & MAP_FIXED)?0:1, prot, prot, 0); 376 if (rv != KERN_SUCCESS) { 377 error = ENOMEM; 378 goto done2; 379 } 380 vm_map_inherit(&p->p_vmspace->vm_map, 381 attach_va, attach_va + size, VM_INHERIT_SHARE); 382 383 shmmap_s->va = attach_va; 384 shmmap_s->shmid = shmid; 385 shmseg->shm_lpid = p->p_pid; 386 shmseg->shm_atime = time_second; 387 shmseg->shm_nattch++; 388 td->td_retval[0] = attach_va; 389done2: 390 mtx_unlock(&Giant); 391 return (error); 392} 393 394int 395shmat(td, uap) 396 struct thread *td; 397 struct shmat_args *uap; 398{ 399 return kern_shmat(td, uap->shmid, uap->shmaddr, uap->shmflg, 0); 400} 401 402struct oshmid_ds { 403 struct ipc_perm shm_perm; /* operation perms */ 404 int shm_segsz; /* size of segment (bytes) */ 405 ushort shm_cpid; /* pid, creator */ 406 ushort shm_lpid; /* pid, last operation */ 407 short shm_nattch; /* no. of current attaches */ 408 time_t shm_atime; /* last attach time */ 409 time_t shm_dtime; /* last detach time */ 410 time_t shm_ctime; /* last change time */ 411 void *shm_handle; /* internal handle for shm segment */ 412}; 413 414struct oshmctl_args { 415 int shmid; 416 int cmd; 417 struct oshmid_ds *ubuf; 418}; 419 420/* 421 * MPSAFE 422 */ 423static int 424oshmctl(td, uap) 425 struct thread *td; 426 struct oshmctl_args *uap; 427{ 428#ifdef COMPAT_43 429 int error = 0; 430 struct shmid_ds *shmseg; 431 struct oshmid_ds outbuf; 432 433 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 434 return (ENOSYS); 435 mtx_lock(&Giant); 436 shmseg = shm_find_segment_by_shmid(uap->shmid, 0); 437 if (shmseg == NULL) { 438 error = EINVAL; 439 goto done2; 440 } 441 switch (uap->cmd) { 442 case IPC_STAT: 443 error = ipcperm(td, &shmseg->shm_perm, IPC_R); 444 if (error) 445 goto done2; 446 outbuf.shm_perm = shmseg->shm_perm; 447 outbuf.shm_segsz = shmseg->shm_segsz; 448 outbuf.shm_cpid = shmseg->shm_cpid; 449 outbuf.shm_lpid = shmseg->shm_lpid; 450 outbuf.shm_nattch = shmseg->shm_nattch; 451 outbuf.shm_atime = shmseg->shm_atime; 452 outbuf.shm_dtime = shmseg->shm_dtime; 453 outbuf.shm_ctime = shmseg->shm_ctime; 454 outbuf.shm_handle = shmseg->shm_internal; 455 error = copyout(&outbuf, uap->ubuf, sizeof(outbuf)); 456 if (error) 457 goto done2; 458 break; 459 default: 460 /* XXX casting to (sy_call_t *) is bogus, as usual. */ 461 error = ((sy_call_t *)shmctl)(td, uap); 462 break; 463 } 464done2: 465 mtx_unlock(&Giant); 466 return (error); 467#else 468 return (EINVAL); 469#endif 470} 471 472#ifndef _SYS_SYSPROTO_H_ 473struct shmctl_args { 474 int shmid; 475 int cmd; 476 struct shmid_ds *buf; 477}; 478#endif 479 480/* 481 * MPSAFE 482 */ 483int 484kern_shmctl(td, shmid, cmd, buf, bufsz, wantrem) 485 struct thread *td; 486 int shmid; 487 int cmd; 488 void *buf; 489 size_t *bufsz; 490 int wantrem; 491{ 492 int error = 0; 493 struct shmid_ds *shmseg; 494 495 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 496 return (ENOSYS); 497 498 mtx_lock(&Giant); 499 switch (cmd) { 500 case IPC_INFO: 501 memcpy(buf, &shminfo, sizeof(shminfo)); 502 if (bufsz) 503 *bufsz = sizeof(shminfo); 504 td->td_retval[0] = shmalloced; 505 goto done2; 506 case SHM_INFO: { 507 struct shm_info shm_info; 508 shm_info.used_ids = shm_nused; 509 shm_info.shm_rss = 0; /*XXX where to get from ? */ 510 shm_info.shm_tot = 0; /*XXX where to get from ? */ 511 shm_info.shm_swp = 0; /*XXX where to get from ? */ 512 shm_info.swap_attempts = 0; /*XXX where to get from ? */ 513 shm_info.swap_successes = 0; /*XXX where to get from ? */ 514 memcpy(buf, &shm_info, sizeof(shm_info)); 515 if (bufsz) 516 *bufsz = sizeof(shm_info); 517 td->td_retval[0] = shmalloced; 518 goto done2; 519 } 520 } 521 if (cmd == SHM_STAT) 522 shmseg = shm_find_segment_by_shmidx(shmid, wantrem); 523 else 524 shmseg = shm_find_segment_by_shmid(shmid, wantrem); 525 if (shmseg == NULL) { 526 error = EINVAL; 527 goto done2; 528 } 529 switch (cmd) { 530 case SHM_STAT: 531 case IPC_STAT: 532 error = ipcperm(td, &shmseg->shm_perm, IPC_R); 533 if (error) 534 goto done2; 535 memcpy(buf, shmseg, sizeof(struct shmid_ds)); 536 if (bufsz) 537 *bufsz = sizeof(struct shmid_ds); 538 if (cmd == SHM_STAT) 539 td->td_retval[0] = IXSEQ_TO_IPCID(shmid, shmseg->shm_perm); 540 break; 541 case IPC_SET: { 542 struct shmid_ds *shmid; 543 544 shmid = (struct shmid_ds *)buf; 545 error = ipcperm(td, &shmseg->shm_perm, IPC_M); 546 if (error) 547 goto done2; 548 shmseg->shm_perm.uid = shmid->shm_perm.uid; 549 shmseg->shm_perm.gid = shmid->shm_perm.gid; 550 shmseg->shm_perm.mode = 551 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 552 (shmid->shm_perm.mode & ACCESSPERMS); 553 shmseg->shm_ctime = time_second; 554 break; 555 } 556 case IPC_RMID: 557 error = ipcperm(td, &shmseg->shm_perm, IPC_M); 558 if (error) 559 goto done2; 560 shmseg->shm_perm.key = IPC_PRIVATE; 561 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 562 if (shmseg->shm_nattch <= 0) { 563 shm_deallocate_segment(shmseg); 564 shm_last_free = IPCID_TO_IX(shmid); 565 } 566 break; 567#if 0 568 case SHM_LOCK: 569 case SHM_UNLOCK: 570#endif 571 default: 572 error = EINVAL; 573 break; 574 } 575done2: 576 mtx_unlock(&Giant); 577 return (error); 578} 579 580int 581shmctl(td, uap) 582 struct thread *td; 583 struct shmctl_args *uap; 584{ 585 int error = 0; 586 struct shmid_ds buf; 587 size_t bufsz; 588 589 /* IPC_SET needs to copyin the buffer before calling kern_shmctl */ 590 if (uap->cmd == IPC_SET) { 591 if ((error = copyin(uap->buf, &buf, sizeof(struct shmid_ds)))) 592 goto done; 593 } 594 595 error = kern_shmctl(td, uap->shmid, uap->cmd, (void *)&buf, &bufsz, 0); 596 if (error) 597 goto done; 598 599 /* Cases in which we need to copyout */ 600 switch (uap->cmd) { 601 case IPC_INFO: 602 case SHM_INFO: 603 case SHM_STAT: 604 case IPC_STAT: 605 error = copyout(&buf, uap->buf, bufsz); 606 break; 607 } 608 609done: 610 if (error) { 611 /* Invalidate the return value */ 612 td->td_retval[0] = -1; 613 } 614 return (error); 615} 616 617 618#ifndef _SYS_SYSPROTO_H_ 619struct shmget_args { 620 key_t key; 621 size_t size; 622 int shmflg; 623}; 624#endif 625 626static int 627shmget_existing(td, uap, mode, segnum) 628 struct thread *td; 629 struct shmget_args *uap; 630 int mode; 631 int segnum; 632{ 633 struct shmid_ds *shmseg; 634 int error; 635 636 shmseg = &shmsegs[segnum]; 637 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 638 /* 639 * This segment is in the process of being allocated. Wait 640 * until it's done, and look the key up again (in case the 641 * allocation failed or it was freed). 642 */ 643 shmseg->shm_perm.mode |= SHMSEG_WANTED; 644 error = tsleep(shmseg, PLOCK | PCATCH, "shmget", 0); 645 if (error) 646 return (error); 647 return (EAGAIN); 648 } 649 if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL)) 650 return (EEXIST); 651 error = ipcperm(td, &shmseg->shm_perm, mode); 652 if (error) 653 return (error); 654 if (uap->size && uap->size > shmseg->shm_segsz) 655 return (EINVAL); 656 td->td_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 657 return (0); 658} 659 660static int 661shmget_allocate_segment(td, uap, mode) 662 struct thread *td; 663 struct shmget_args *uap; 664 int mode; 665{ 666 int i, segnum, shmid, size; 667 struct ucred *cred = td->td_ucred; 668 struct shmid_ds *shmseg; 669 struct shm_handle *shm_handle; 670 671 GIANT_REQUIRED; 672 673 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax) 674 return (EINVAL); 675 if (shm_nused >= shminfo.shmmni) /* Any shmids left? */ 676 return (ENOSPC); 677 size = round_page(uap->size); 678 if (shm_committed + btoc(size) > shminfo.shmall) 679 return (ENOMEM); 680 if (shm_last_free < 0) { 681 shmrealloc(); /* Maybe expand the shmsegs[] array. */ 682 for (i = 0; i < shmalloced; i++) 683 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 684 break; 685 if (i == shmalloced) 686 return (ENOSPC); 687 segnum = i; 688 } else { 689 segnum = shm_last_free; 690 shm_last_free = -1; 691 } 692 shmseg = &shmsegs[segnum]; 693 /* 694 * In case we sleep in malloc(), mark the segment present but deleted 695 * so that noone else tries to create the same key. 696 */ 697 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 698 shmseg->shm_perm.key = uap->key; 699 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff; 700 shm_handle = (struct shm_handle *) 701 malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK); 702 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 703 704 /* 705 * We make sure that we have allocated a pager before we need 706 * to. 707 */ 708 if (shm_use_phys) { 709 shm_handle->shm_object = 710 vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0); 711 } else { 712 shm_handle->shm_object = 713 vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0); 714 } 715 VM_OBJECT_LOCK(shm_handle->shm_object); 716 vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING); 717 vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT); 718 VM_OBJECT_UNLOCK(shm_handle->shm_object); 719 720 shmseg->shm_internal = shm_handle; 721 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 722 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 723 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 724 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 725 shmseg->shm_segsz = uap->size; 726 shmseg->shm_cpid = td->td_proc->p_pid; 727 shmseg->shm_lpid = shmseg->shm_nattch = 0; 728 shmseg->shm_atime = shmseg->shm_dtime = 0; 729 shmseg->shm_ctime = time_second; 730 shm_committed += btoc(size); 731 shm_nused++; 732 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 733 /* 734 * Somebody else wanted this key while we were asleep. Wake 735 * them up now. 736 */ 737 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 738 wakeup(shmseg); 739 } 740 td->td_retval[0] = shmid; 741 return (0); 742} 743 744/* 745 * MPSAFE 746 */ 747int 748shmget(td, uap) 749 struct thread *td; 750 struct shmget_args *uap; 751{ 752 int segnum, mode; 753 int error; 754 755 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 756 return (ENOSYS); 757 mtx_lock(&Giant); 758 mode = uap->shmflg & ACCESSPERMS; 759 if (uap->key != IPC_PRIVATE) { 760 again: 761 segnum = shm_find_segment_by_key(uap->key); 762 if (segnum >= 0) { 763 error = shmget_existing(td, uap, mode, segnum); 764 if (error == EAGAIN) 765 goto again; 766 goto done2; 767 } 768 if ((uap->shmflg & IPC_CREAT) == 0) { 769 error = ENOENT; 770 goto done2; 771 } 772 } 773 error = shmget_allocate_segment(td, uap, mode); 774done2: 775 mtx_unlock(&Giant); 776 return (error); 777} 778 779/* 780 * MPSAFE 781 */ 782int 783shmsys(td, uap) 784 struct thread *td; 785 /* XXX actually varargs. */ 786 struct shmsys_args /* { 787 u_int which; 788 int a2; 789 int a3; 790 int a4; 791 } */ *uap; 792{ 793 int error; 794 795 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 796 return (ENOSYS); 797 if (uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0])) 798 return (EINVAL); 799 mtx_lock(&Giant); 800 error = (*shmcalls[uap->which])(td, &uap->a2); 801 mtx_unlock(&Giant); 802 return (error); 803} 804 805static void 806shmfork_myhook(p1, p2) 807 struct proc *p1, *p2; 808{ 809 struct shmmap_state *shmmap_s; 810 size_t size; 811 int i; 812 813 size = shminfo.shmseg * sizeof(struct shmmap_state); 814 shmmap_s = malloc(size, M_SHM, M_WAITOK); 815 bcopy(p1->p_vmspace->vm_shm, shmmap_s, size); 816 p2->p_vmspace->vm_shm = shmmap_s; 817 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 818 if (shmmap_s->shmid != -1) 819 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++; 820} 821 822static void 823shmexit_myhook(struct vmspace *vm) 824{ 825 struct shmmap_state *base, *shm; 826 int i; 827 828 GIANT_REQUIRED; 829 830 if ((base = vm->vm_shm) != NULL) { 831 vm->vm_shm = NULL; 832 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) { 833 if (shm->shmid != -1) 834 shm_delete_mapping(vm, shm); 835 } 836 free(base, M_SHM); 837 } 838} 839 840static void 841shmrealloc(void) 842{ 843 int i; 844 struct shmid_ds *newsegs; 845 846 if (shmalloced >= shminfo.shmmni) 847 return; 848 849 newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK); 850 if (newsegs == NULL) 851 return; 852 for (i = 0; i < shmalloced; i++) 853 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0])); 854 for (; i < shminfo.shmmni; i++) { 855 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 856 shmsegs[i].shm_perm.seq = 0; 857 } 858 free(shmsegs, M_SHM); 859 shmsegs = newsegs; 860 shmalloced = shminfo.shmmni; 861} 862 863static void 864shminit() 865{ 866 int i; 867 868 TUNABLE_INT_FETCH("kern.ipc.shmmaxpgs", &shminfo.shmall); 869 for (i = PAGE_SIZE; i > 0; i--) { 870 shminfo.shmmax = shminfo.shmall * PAGE_SIZE; 871 if (shminfo.shmmax >= shminfo.shmall) 872 break; 873 } 874 TUNABLE_INT_FETCH("kern.ipc.shmmin", &shminfo.shmmin); 875 TUNABLE_INT_FETCH("kern.ipc.shmmni", &shminfo.shmmni); 876 TUNABLE_INT_FETCH("kern.ipc.shmseg", &shminfo.shmseg); 877 TUNABLE_INT_FETCH("kern.ipc.shm_use_phys", &shm_use_phys); 878 879 shmalloced = shminfo.shmmni; 880 shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK); 881 if (shmsegs == NULL) 882 panic("cannot allocate initial memory for sysvshm"); 883 for (i = 0; i < shmalloced; i++) { 884 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 885 shmsegs[i].shm_perm.seq = 0; 886 } 887 shm_last_free = 0; 888 shm_nused = 0; 889 shm_committed = 0; 890 shmexit_hook = &shmexit_myhook; 891 shmfork_hook = &shmfork_myhook; 892} 893 894static int 895shmunload() 896{ 897 898 if (shm_nused > 0) 899 return (EBUSY); 900 901 free(shmsegs, M_SHM); 902 shmexit_hook = NULL; 903 shmfork_hook = NULL; 904 return (0); 905} 906 907static int 908sysctl_shmsegs(SYSCTL_HANDLER_ARGS) 909{ 910 911 return (SYSCTL_OUT(req, shmsegs, shmalloced * sizeof(shmsegs[0]))); 912} 913 914static int 915sysvshm_modload(struct module *module, int cmd, void *arg) 916{ 917 int error = 0; 918 919 switch (cmd) { 920 case MOD_LOAD: 921 shminit(); 922 break; 923 case MOD_UNLOAD: 924 error = shmunload(); 925 break; 926 case MOD_SHUTDOWN: 927 break; 928 default: 929 error = EINVAL; 930 break; 931 } 932 return (error); 933} 934 935static moduledata_t sysvshm_mod = { 936 "sysvshm", 937 &sysvshm_modload, 938 NULL 939}; 940 941SYSCALL_MODULE_HELPER(shmsys); 942SYSCALL_MODULE_HELPER(shmat); 943SYSCALL_MODULE_HELPER(shmctl); 944SYSCALL_MODULE_HELPER(shmdt); 945SYSCALL_MODULE_HELPER(shmget); 946 947DECLARE_MODULE(sysvshm, sysvshm_mod, 948 SI_SUB_SYSV_SHM, SI_ORDER_FIRST); 949MODULE_VERSION(sysvshm, 1); 950