sysv_shm.c revision 46116
1/* $Id: sysv_shm.c,v 1.40 1999/01/21 08:29:04 dillon Exp $ */ 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 37#include <sys/param.h> 38#include <sys/systm.h> 39#include <sys/sysproto.h> 40#include <sys/kernel.h> 41#include <sys/shm.h> 42#include <sys/proc.h> 43#include <sys/malloc.h> 44#include <sys/mman.h> 45#include <sys/stat.h> 46#include <sys/sysent.h> 47 48#include <vm/vm.h> 49#include <vm/vm_param.h> 50#include <vm/vm_prot.h> 51#include <sys/lock.h> 52#include <vm/pmap.h> 53#include <vm/vm_object.h> 54#include <vm/vm_map.h> 55#include <vm/vm_page.h> 56#include <vm/vm_pager.h> 57#include <vm/vm_inherit.h> 58 59#ifndef _SYS_SYSPROTO_H_ 60struct shmat_args; 61extern int shmat __P((struct proc *p, struct shmat_args *uap)); 62struct shmctl_args; 63extern int shmctl __P((struct proc *p, struct shmctl_args *uap)); 64struct shmdt_args; 65extern int shmdt __P((struct proc *p, struct shmdt_args *uap)); 66struct shmget_args; 67extern int shmget __P((struct proc *p, struct shmget_args *uap)); 68#endif 69 70static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments"); 71 72static void shminit __P((void *)); 73SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL) 74 75struct oshmctl_args; 76static int oshmctl __P((struct proc *p, struct oshmctl_args *uap)); 77static int shmget_allocate_segment __P((struct proc *p, struct shmget_args *uap, int mode)); 78static int shmget_existing __P((struct proc *p, struct shmget_args *uap, int mode, int segnum)); 79 80/* XXX casting to (sy_call_t *) is bogus, as usual. */ 81static sy_call_t *shmcalls[] = { 82 (sy_call_t *)shmat, (sy_call_t *)oshmctl, 83 (sy_call_t *)shmdt, (sy_call_t *)shmget, 84 (sy_call_t *)shmctl 85}; 86 87#define SHMSEG_FREE 0x0200 88#define SHMSEG_REMOVED 0x0400 89#define SHMSEG_ALLOCATED 0x0800 90#define SHMSEG_WANTED 0x1000 91 92static int shm_last_free, shm_nused, shm_committed; 93struct shmid_ds *shmsegs; 94 95struct shm_handle { 96 /* vm_offset_t kva; */ 97 vm_object_t shm_object; 98}; 99 100struct shmmap_state { 101 vm_offset_t va; 102 int shmid; 103}; 104 105static void shm_deallocate_segment __P((struct shmid_ds *)); 106static int shm_find_segment_by_key __P((key_t)); 107static struct shmid_ds *shm_find_segment_by_shmid __P((int)); 108static int shm_delete_mapping __P((struct proc *, struct shmmap_state *)); 109 110static int 111shm_find_segment_by_key(key) 112 key_t key; 113{ 114 int i; 115 116 for (i = 0; i < shminfo.shmmni; i++) 117 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) && 118 shmsegs[i].shm_perm.key == key) 119 return i; 120 return -1; 121} 122 123static struct shmid_ds * 124shm_find_segment_by_shmid(shmid) 125 int shmid; 126{ 127 int segnum; 128 struct shmid_ds *shmseg; 129 130 segnum = IPCID_TO_IX(shmid); 131 if (segnum < 0 || segnum >= shminfo.shmmni) 132 return NULL; 133 shmseg = &shmsegs[segnum]; 134 if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED)) 135 != SHMSEG_ALLOCATED || 136 shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid)) 137 return NULL; 138 return shmseg; 139} 140 141static void 142shm_deallocate_segment(shmseg) 143 struct shmid_ds *shmseg; 144{ 145 struct shm_handle *shm_handle; 146 size_t size; 147 148 shm_handle = shmseg->shm_internal; 149 vm_object_deallocate(shm_handle->shm_object); 150 free((caddr_t)shm_handle, M_SHM); 151 shmseg->shm_internal = NULL; 152 size = round_page(shmseg->shm_segsz); 153 shm_committed -= btoc(size); 154 shm_nused--; 155 shmseg->shm_perm.mode = SHMSEG_FREE; 156} 157 158static int 159shm_delete_mapping(p, shmmap_s) 160 struct proc *p; 161 struct shmmap_state *shmmap_s; 162{ 163 struct shmid_ds *shmseg; 164 int segnum, result; 165 size_t size; 166 167 segnum = IPCID_TO_IX(shmmap_s->shmid); 168 shmseg = &shmsegs[segnum]; 169 size = round_page(shmseg->shm_segsz); 170 result = vm_map_remove(&p->p_vmspace->vm_map, shmmap_s->va, shmmap_s->va + size); 171 if (result != KERN_SUCCESS) 172 return EINVAL; 173 shmmap_s->shmid = -1; 174 shmseg->shm_dtime = time_second; 175 if ((--shmseg->shm_nattch <= 0) && 176 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { 177 shm_deallocate_segment(shmseg); 178 shm_last_free = segnum; 179 } 180 return 0; 181} 182 183#ifndef _SYS_SYSPROTO_H_ 184struct shmdt_args { 185 void *shmaddr; 186}; 187#endif 188 189int 190shmdt(p, uap) 191 struct proc *p; 192 struct shmdt_args *uap; 193{ 194 struct shmmap_state *shmmap_s; 195 int i; 196 197 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 198 if (shmmap_s == NULL) 199 return EINVAL; 200 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 201 if (shmmap_s->shmid != -1 && 202 shmmap_s->va == (vm_offset_t)uap->shmaddr) 203 break; 204 if (i == shminfo.shmseg) 205 return EINVAL; 206 return shm_delete_mapping(p, shmmap_s); 207} 208 209#ifndef _SYS_SYSPROTO_H_ 210struct shmat_args { 211 int shmid; 212 void *shmaddr; 213 int shmflg; 214}; 215#endif 216 217int 218shmat(p, uap) 219 struct proc *p; 220 struct shmat_args *uap; 221{ 222 int error, i, flags; 223 struct shmid_ds *shmseg; 224 struct shmmap_state *shmmap_s = NULL; 225 struct shm_handle *shm_handle; 226 vm_offset_t attach_va; 227 vm_prot_t prot; 228 vm_size_t size; 229 int rv; 230 231 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 232 if (shmmap_s == NULL) { 233 size = shminfo.shmseg * sizeof(struct shmmap_state); 234 shmmap_s = malloc(size, M_SHM, M_WAITOK); 235 for (i = 0; i < shminfo.shmseg; i++) 236 shmmap_s[i].shmid = -1; 237 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 238 } 239 shmseg = shm_find_segment_by_shmid(uap->shmid); 240 if (shmseg == NULL) 241 return EINVAL; 242 error = ipcperm(p, &shmseg->shm_perm, 243 (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 244 if (error) 245 return error; 246 for (i = 0; i < shminfo.shmseg; i++) { 247 if (shmmap_s->shmid == -1) 248 break; 249 shmmap_s++; 250 } 251 if (i >= shminfo.shmseg) 252 return EMFILE; 253 size = round_page(shmseg->shm_segsz); 254 prot = VM_PROT_READ; 255 if ((uap->shmflg & SHM_RDONLY) == 0) 256 prot |= VM_PROT_WRITE; 257 flags = MAP_ANON | MAP_SHARED; 258 if (uap->shmaddr) { 259 flags |= MAP_FIXED; 260 if (uap->shmflg & SHM_RND) 261 attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1); 262 else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0) 263 attach_va = (vm_offset_t)uap->shmaddr; 264 else 265 return EINVAL; 266 } else { 267 /* This is just a hint to vm_map_find() about where to put it. */ 268 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_taddr + MAXTSIZ + MAXDSIZ); 269 } 270 271 shm_handle = shmseg->shm_internal; 272 vm_object_reference(shm_handle->shm_object); 273 rv = vm_map_find(&p->p_vmspace->vm_map, shm_handle->shm_object, 274 0, &attach_va, size, (flags & MAP_FIXED)?0:1, prot, prot, 0); 275 if (rv != KERN_SUCCESS) { 276 return ENOMEM; 277 } 278 vm_map_inherit(&p->p_vmspace->vm_map, 279 attach_va, attach_va + size, VM_INHERIT_SHARE); 280 281 shmmap_s->va = attach_va; 282 shmmap_s->shmid = uap->shmid; 283 shmseg->shm_lpid = p->p_pid; 284 shmseg->shm_atime = time_second; 285 shmseg->shm_nattch++; 286 p->p_retval[0] = attach_va; 287 return 0; 288} 289 290struct oshmid_ds { 291 struct ipc_perm shm_perm; /* operation perms */ 292 int shm_segsz; /* size of segment (bytes) */ 293 ushort shm_cpid; /* pid, creator */ 294 ushort shm_lpid; /* pid, last operation */ 295 short shm_nattch; /* no. of current attaches */ 296 time_t shm_atime; /* last attach time */ 297 time_t shm_dtime; /* last detach time */ 298 time_t shm_ctime; /* last change time */ 299 void *shm_handle; /* internal handle for shm segment */ 300}; 301 302struct oshmctl_args { 303 int shmid; 304 int cmd; 305 struct oshmid_ds *ubuf; 306}; 307 308static int 309oshmctl(p, uap) 310 struct proc *p; 311 struct oshmctl_args *uap; 312{ 313#ifdef COMPAT_43 314 int error; 315 struct shmid_ds *shmseg; 316 struct oshmid_ds outbuf; 317 318 shmseg = shm_find_segment_by_shmid(uap->shmid); 319 if (shmseg == NULL) 320 return EINVAL; 321 switch (uap->cmd) { 322 case IPC_STAT: 323 error = ipcperm(p, &shmseg->shm_perm, IPC_R); 324 if (error) 325 return error; 326 outbuf.shm_perm = shmseg->shm_perm; 327 outbuf.shm_segsz = shmseg->shm_segsz; 328 outbuf.shm_cpid = shmseg->shm_cpid; 329 outbuf.shm_lpid = shmseg->shm_lpid; 330 outbuf.shm_nattch = shmseg->shm_nattch; 331 outbuf.shm_atime = shmseg->shm_atime; 332 outbuf.shm_dtime = shmseg->shm_dtime; 333 outbuf.shm_ctime = shmseg->shm_ctime; 334 outbuf.shm_handle = shmseg->shm_internal; 335 error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf)); 336 if (error) 337 return error; 338 break; 339 default: 340 /* XXX casting to (sy_call_t *) is bogus, as usual. */ 341 return ((sy_call_t *)shmctl)(p, uap); 342 } 343 return 0; 344#else 345 return EINVAL; 346#endif 347} 348 349#ifndef _SYS_SYSPROTO_H_ 350struct shmctl_args { 351 int shmid; 352 int cmd; 353 struct shmid_ds *buf; 354}; 355#endif 356 357int 358shmctl(p, uap) 359 struct proc *p; 360 struct shmctl_args *uap; 361{ 362 int error; 363 struct shmid_ds inbuf; 364 struct shmid_ds *shmseg; 365 366 shmseg = shm_find_segment_by_shmid(uap->shmid); 367 if (shmseg == NULL) 368 return EINVAL; 369 switch (uap->cmd) { 370 case IPC_STAT: 371 error = ipcperm(p, &shmseg->shm_perm, IPC_R); 372 if (error) 373 return error; 374 error = copyout((caddr_t)shmseg, uap->buf, sizeof(inbuf)); 375 if (error) 376 return error; 377 break; 378 case IPC_SET: 379 error = ipcperm(p, &shmseg->shm_perm, IPC_M); 380 if (error) 381 return error; 382 error = copyin(uap->buf, (caddr_t)&inbuf, sizeof(inbuf)); 383 if (error) 384 return error; 385 shmseg->shm_perm.uid = inbuf.shm_perm.uid; 386 shmseg->shm_perm.gid = inbuf.shm_perm.gid; 387 shmseg->shm_perm.mode = 388 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 389 (inbuf.shm_perm.mode & ACCESSPERMS); 390 shmseg->shm_ctime = time_second; 391 break; 392 case IPC_RMID: 393 error = ipcperm(p, &shmseg->shm_perm, IPC_M); 394 if (error) 395 return error; 396 shmseg->shm_perm.key = IPC_PRIVATE; 397 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 398 if (shmseg->shm_nattch <= 0) { 399 shm_deallocate_segment(shmseg); 400 shm_last_free = IPCID_TO_IX(uap->shmid); 401 } 402 break; 403#if 0 404 case SHM_LOCK: 405 case SHM_UNLOCK: 406#endif 407 default: 408 return EINVAL; 409 } 410 return 0; 411} 412 413#ifndef _SYS_SYSPROTO_H_ 414struct shmget_args { 415 key_t key; 416 size_t size; 417 int shmflg; 418}; 419#endif 420 421static int 422shmget_existing(p, uap, mode, segnum) 423 struct proc *p; 424 struct shmget_args *uap; 425 int mode; 426 int segnum; 427{ 428 struct shmid_ds *shmseg; 429 int error; 430 431 shmseg = &shmsegs[segnum]; 432 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 433 /* 434 * This segment is in the process of being allocated. Wait 435 * until it's done, and look the key up again (in case the 436 * allocation failed or it was freed). 437 */ 438 shmseg->shm_perm.mode |= SHMSEG_WANTED; 439 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0); 440 if (error) 441 return error; 442 return EAGAIN; 443 } 444 error = ipcperm(p, &shmseg->shm_perm, mode); 445 if (error) 446 return error; 447 if (uap->size && uap->size > shmseg->shm_segsz) 448 return EINVAL; 449 if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL)) 450 return EEXIST; 451 p->p_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 452 return 0; 453} 454 455static int 456shmget_allocate_segment(p, uap, mode) 457 struct proc *p; 458 struct shmget_args *uap; 459 int mode; 460{ 461 int i, segnum, shmid, size; 462 struct ucred *cred = p->p_ucred; 463 struct shmid_ds *shmseg; 464 struct shm_handle *shm_handle; 465 466 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax) 467 return EINVAL; 468 if (shm_nused >= shminfo.shmmni) /* any shmids left? */ 469 return ENOSPC; 470 size = round_page(uap->size); 471 if (shm_committed + btoc(size) > shminfo.shmall) 472 return ENOMEM; 473 if (shm_last_free < 0) { 474 for (i = 0; i < shminfo.shmmni; i++) 475 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 476 break; 477 if (i == shminfo.shmmni) 478 panic("shmseg free count inconsistent"); 479 segnum = i; 480 } else { 481 segnum = shm_last_free; 482 shm_last_free = -1; 483 } 484 shmseg = &shmsegs[segnum]; 485 /* 486 * In case we sleep in malloc(), mark the segment present but deleted 487 * so that noone else tries to create the same key. 488 */ 489 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 490 shmseg->shm_perm.key = uap->key; 491 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff; 492 shm_handle = (struct shm_handle *) 493 malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK); 494 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 495 496 /* 497 * We make sure that we have allocated a pager before we need 498 * to. 499 */ 500 shm_handle->shm_object = 501 vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0); 502 vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING); 503 vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT); 504 505 shmseg->shm_internal = shm_handle; 506 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 507 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 508 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 509 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 510 shmseg->shm_segsz = uap->size; 511 shmseg->shm_cpid = p->p_pid; 512 shmseg->shm_lpid = shmseg->shm_nattch = 0; 513 shmseg->shm_atime = shmseg->shm_dtime = 0; 514 shmseg->shm_ctime = time_second; 515 shm_committed += btoc(size); 516 shm_nused++; 517 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 518 /* 519 * Somebody else wanted this key while we were asleep. Wake 520 * them up now. 521 */ 522 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 523 wakeup((caddr_t)shmseg); 524 } 525 p->p_retval[0] = shmid; 526 return 0; 527} 528 529int 530shmget(p, uap) 531 struct proc *p; 532 struct shmget_args *uap; 533{ 534 int segnum, mode, error; 535 536 mode = uap->shmflg & ACCESSPERMS; 537 if (uap->key != IPC_PRIVATE) { 538 again: 539 segnum = shm_find_segment_by_key(uap->key); 540 if (segnum >= 0) { 541 error = shmget_existing(p, uap, mode, segnum); 542 if (error == EAGAIN) 543 goto again; 544 return error; 545 } 546 if ((uap->shmflg & IPC_CREAT) == 0) 547 return ENOENT; 548 } 549 return shmget_allocate_segment(p, uap, mode); 550} 551 552int 553shmsys(p, uap) 554 struct proc *p; 555 /* XXX actually varargs. */ 556 struct shmsys_args /* { 557 u_int which; 558 int a2; 559 int a3; 560 int a4; 561 } */ *uap; 562{ 563 564 if (uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0])) 565 return EINVAL; 566 return ((*shmcalls[uap->which])(p, &uap->a2)); 567} 568 569void 570shmfork(p1, p2) 571 struct proc *p1, *p2; 572{ 573 struct shmmap_state *shmmap_s; 574 size_t size; 575 int i; 576 577 size = shminfo.shmseg * sizeof(struct shmmap_state); 578 shmmap_s = malloc(size, M_SHM, M_WAITOK); 579 bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size); 580 p2->p_vmspace->vm_shm = (caddr_t)shmmap_s; 581 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 582 if (shmmap_s->shmid != -1) 583 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++; 584} 585 586void 587shmexit(p) 588 struct proc *p; 589{ 590 struct shmmap_state *shmmap_s; 591 int i; 592 593 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 594 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 595 if (shmmap_s->shmid != -1) 596 shm_delete_mapping(p, shmmap_s); 597 free((caddr_t)p->p_vmspace->vm_shm, M_SHM); 598 p->p_vmspace->vm_shm = NULL; 599} 600 601void 602shminit(dummy) 603 void *dummy; 604{ 605 int i; 606 for (i = 0; i < shminfo.shmmni; i++) { 607 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 608 shmsegs[i].shm_perm.seq = 0; 609 } 610 shm_last_free = 0; 611 shm_nused = 0; 612 shm_committed = 0; 613} 614