sysv_shm.c revision 10428
1/* $Id: sysv_shm.c,v 1.7 1995/08/28 09:18:48 julian 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 <sys/types.h> 35#include <sys/param.h> 36#include <sys/kernel.h> 37#include <sys/shm.h> 38#include <sys/proc.h> 39#include <sys/uio.h> 40#include <sys/time.h> 41#include <sys/malloc.h> 42#include <sys/mman.h> 43#include <sys/systm.h> 44#include <sys/stat.h> 45 46#include <vm/vm.h> 47#include <vm/vm_map.h> 48#include <vm/vm_map.h> 49#include <vm/vm_kern.h> 50 51static void shminit __P((caddr_t)); 52SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL) 53 54int oshmctl(); 55int shmat(), shmctl(), shmdt(), shmget(); 56int (*shmcalls[])() = { shmat, oshmctl, shmdt, shmget, shmctl }; 57 58#define SHMSEG_FREE 0x0200 59#define SHMSEG_REMOVED 0x0400 60#define SHMSEG_ALLOCATED 0x0800 61#define SHMSEG_WANTED 0x1000 62 63vm_map_t sysvshm_map; 64int shm_last_free, shm_nused, shm_committed; 65struct shmid_ds *shmsegs; 66 67struct shm_handle { 68 vm_offset_t kva; 69}; 70 71struct shmmap_state { 72 vm_offset_t va; 73 int shmid; 74}; 75 76static void shm_deallocate_segment __P((struct shmid_ds *)); 77static int shm_find_segment_by_key __P((key_t)); 78static struct shmid_ds *shm_find_segment_by_shmid __P((int)); 79static int shm_delete_mapping __P((struct proc *, struct shmmap_state *)); 80 81static int 82shm_find_segment_by_key(key) 83 key_t key; 84{ 85 int i; 86 87 for (i = 0; i < shminfo.shmmni; i++) 88 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) && 89 shmsegs[i].shm_perm.key == key) 90 return i; 91 return -1; 92} 93 94static struct shmid_ds * 95shm_find_segment_by_shmid(shmid) 96 int shmid; 97{ 98 int segnum; 99 struct shmid_ds *shmseg; 100 101 segnum = IPCID_TO_IX(shmid); 102 if (segnum < 0 || segnum >= shminfo.shmmni) 103 return NULL; 104 shmseg = &shmsegs[segnum]; 105 if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED)) 106 != SHMSEG_ALLOCATED || 107 shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid)) 108 return NULL; 109 return shmseg; 110} 111 112static void 113shm_deallocate_segment(shmseg) 114 struct shmid_ds *shmseg; 115{ 116 struct shm_handle *shm_handle; 117 size_t size; 118 119 shm_handle = shmseg->shm_internal; 120 size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET; 121 (void) vm_map_remove(sysvshm_map, shm_handle->kva, shm_handle->kva + size); 122 free((caddr_t)shm_handle, M_SHM); 123 shmseg->shm_internal = NULL; 124 shm_committed -= btoc(size); 125 shm_nused--; 126 shmseg->shm_perm.mode = SHMSEG_FREE; 127} 128 129static int 130shm_delete_mapping(p, shmmap_s) 131 struct proc *p; 132 struct shmmap_state *shmmap_s; 133{ 134 struct shmid_ds *shmseg; 135 int segnum, result; 136 size_t size; 137 138 segnum = IPCID_TO_IX(shmmap_s->shmid); 139 shmseg = &shmsegs[segnum]; 140 size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET; 141 result = vm_map_remove(&p->p_vmspace->vm_map, shmmap_s->va, shmmap_s->va + size); 142 if (result != KERN_SUCCESS) 143 return EINVAL; 144 shmmap_s->shmid = -1; 145 shmseg->shm_dtime = time.tv_sec; 146 if ((--shmseg->shm_nattch <= 0) && 147 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { 148 shm_deallocate_segment(shmseg); 149 shm_last_free = segnum; 150 } 151 return 0; 152} 153 154struct shmdt_args { 155 void *shmaddr; 156}; 157int 158shmdt(p, uap, retval) 159 struct proc *p; 160 struct shmdt_args *uap; 161 int *retval; 162{ 163 struct shmmap_state *shmmap_s; 164 int i; 165 166 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 167 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 168 if (shmmap_s->shmid != -1 && 169 shmmap_s->va == (vm_offset_t)uap->shmaddr) 170 break; 171 if (i == shminfo.shmseg) 172 return EINVAL; 173 return shm_delete_mapping(p, shmmap_s); 174} 175 176struct shmat_args { 177 int shmid; 178 void *shmaddr; 179 int shmflg; 180}; 181int 182shmat(p, uap, retval) 183 struct proc *p; 184 struct shmat_args *uap; 185 int *retval; 186{ 187 int error, i, flags; 188 struct ucred *cred = p->p_ucred; 189 struct shmid_ds *shmseg; 190 struct shmmap_state *shmmap_s = NULL; 191 vm_offset_t attach_va; 192 vm_prot_t prot; 193 vm_size_t size; 194 195 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 196 if (shmmap_s == NULL) { 197 size = shminfo.shmseg * sizeof(struct shmmap_state); 198 shmmap_s = malloc(size, M_SHM, M_WAITOK); 199 for (i = 0; i < shminfo.shmseg; i++) 200 shmmap_s[i].shmid = -1; 201 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 202 } 203 shmseg = shm_find_segment_by_shmid(uap->shmid); 204 if (shmseg == NULL) 205 return EINVAL; 206 error = ipcperm(cred, &shmseg->shm_perm, 207 (uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 208 if (error) 209 return error; 210 for (i = 0; i < shminfo.shmseg; i++) { 211 if (shmmap_s->shmid == -1) 212 break; 213 shmmap_s++; 214 } 215 if (i >= shminfo.shmseg) 216 return EMFILE; 217 size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET; 218 prot = VM_PROT_READ; 219 if ((uap->shmflg & SHM_RDONLY) == 0) 220 prot |= VM_PROT_WRITE; 221 flags = MAP_ANON | MAP_SHARED; 222 if (uap->shmaddr) { 223 flags |= MAP_FIXED; 224 if (uap->shmflg & SHM_RND) 225 attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1); 226 else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0) 227 attach_va = (vm_offset_t)uap->shmaddr; 228 else 229 return EINVAL; 230 } else { 231 /* This is just a hint to vm_mmap() about where to put it. */ 232 attach_va = round_page(p->p_vmspace->vm_daddr + MAXDSIZ); 233 } 234 error = vm_mmap(&p->p_vmspace->vm_map, &attach_va, size, prot, 235 VM_PROT_DEFAULT, flags, (caddr_t) uap->shmid, 0); 236 if (error) 237 return error; 238 shmmap_s->va = attach_va; 239 shmmap_s->shmid = uap->shmid; 240 shmseg->shm_lpid = p->p_pid; 241 shmseg->shm_atime = time.tv_sec; 242 shmseg->shm_nattch++; 243 *retval = attach_va; 244 return 0; 245} 246 247struct oshmid_ds { 248 struct ipc_perm shm_perm; /* operation perms */ 249 int shm_segsz; /* size of segment (bytes) */ 250 ushort shm_cpid; /* pid, creator */ 251 ushort shm_lpid; /* pid, last operation */ 252 short shm_nattch; /* no. of current attaches */ 253 time_t shm_atime; /* last attach time */ 254 time_t shm_dtime; /* last detach time */ 255 time_t shm_ctime; /* last change time */ 256 void *shm_handle; /* internal handle for shm segment */ 257}; 258 259struct oshmctl_args { 260 int shmid; 261 int cmd; 262 struct oshmid_ds *ubuf; 263}; 264 265int 266oshmctl(p, uap, retval) 267 struct proc *p; 268 struct oshmctl_args *uap; 269 int *retval; 270{ 271#ifdef COMPAT_43 272 int error; 273 struct ucred *cred = p->p_ucred; 274 struct shmid_ds *shmseg; 275 struct oshmid_ds outbuf; 276 277 shmseg = shm_find_segment_by_shmid(uap->shmid); 278 if (shmseg == NULL) 279 return EINVAL; 280 switch (uap->cmd) { 281 case IPC_STAT: 282 error = ipcperm(cred, &shmseg->shm_perm, IPC_R); 283 if (error) 284 return error; 285 outbuf.shm_perm = shmseg->shm_perm; 286 outbuf.shm_segsz = shmseg->shm_segsz; 287 outbuf.shm_cpid = shmseg->shm_cpid; 288 outbuf.shm_lpid = shmseg->shm_lpid; 289 outbuf.shm_nattch = shmseg->shm_nattch; 290 outbuf.shm_atime = shmseg->shm_atime; 291 outbuf.shm_dtime = shmseg->shm_dtime; 292 outbuf.shm_ctime = shmseg->shm_ctime; 293 outbuf.shm_handle = shmseg->shm_internal; 294 error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf)); 295 if (error) 296 return error; 297 break; 298 default: 299 return shmctl(p, uap, retval); 300 } 301 return 0; 302#else 303 return EINVAL; 304#endif 305} 306 307struct shmctl_args { 308 int shmid; 309 int cmd; 310 struct shmid_ds *ubuf; 311}; 312int 313shmctl(p, uap, retval) 314 struct proc *p; 315 struct shmctl_args *uap; 316 int *retval; 317{ 318 int error; 319 struct ucred *cred = p->p_ucred; 320 struct shmid_ds inbuf; 321 struct shmid_ds *shmseg; 322 323 shmseg = shm_find_segment_by_shmid(uap->shmid); 324 if (shmseg == NULL) 325 return EINVAL; 326 switch (uap->cmd) { 327 case IPC_STAT: 328 error = ipcperm(cred, &shmseg->shm_perm, IPC_R); 329 if (error) 330 return error; 331 error = copyout((caddr_t)shmseg, uap->ubuf, sizeof(inbuf)); 332 if (error) 333 return error; 334 break; 335 case IPC_SET: 336 error = ipcperm(cred, &shmseg->shm_perm, IPC_M); 337 if (error) 338 return error; 339 error = copyin(uap->ubuf, (caddr_t)&inbuf, sizeof(inbuf)); 340 if (error) 341 return error; 342 shmseg->shm_perm.uid = inbuf.shm_perm.uid; 343 shmseg->shm_perm.gid = inbuf.shm_perm.gid; 344 shmseg->shm_perm.mode = 345 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 346 (inbuf.shm_perm.mode & ACCESSPERMS); 347 shmseg->shm_ctime = time.tv_sec; 348 break; 349 case IPC_RMID: 350 error = ipcperm(cred, &shmseg->shm_perm, IPC_M); 351 if (error) 352 return error; 353 shmseg->shm_perm.key = IPC_PRIVATE; 354 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 355 if (shmseg->shm_nattch <= 0) { 356 shm_deallocate_segment(shmseg); 357 shm_last_free = IPCID_TO_IX(uap->shmid); 358 } 359 break; 360#if 0 361 case SHM_LOCK: 362 case SHM_UNLOCK: 363#endif 364 default: 365 return EINVAL; 366 } 367 return 0; 368} 369 370struct shmget_args { 371 key_t key; 372 size_t size; 373 int shmflg; 374}; 375static int 376shmget_existing(p, uap, mode, segnum, retval) 377 struct proc *p; 378 struct shmget_args *uap; 379 int mode; 380 int segnum; 381 int *retval; 382{ 383 struct shmid_ds *shmseg; 384 struct ucred *cred = p->p_ucred; 385 int error; 386 387 shmseg = &shmsegs[segnum]; 388 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 389 /* 390 * This segment is in the process of being allocated. Wait 391 * until it's done, and look the key up again (in case the 392 * allocation failed or it was freed). 393 */ 394 shmseg->shm_perm.mode |= SHMSEG_WANTED; 395 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0); 396 if (error) 397 return error; 398 return EAGAIN; 399 } 400 error = ipcperm(cred, &shmseg->shm_perm, mode); 401 if (error) 402 return error; 403 if (uap->size && uap->size > shmseg->shm_segsz) 404 return EINVAL; 405 if (uap->shmflg & (IPC_CREAT | IPC_EXCL) == (IPC_CREAT | IPC_EXCL)) 406 return EEXIST; 407 *retval = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 408 return 0; 409} 410 411static int 412shmget_allocate_segment(p, uap, mode, retval) 413 struct proc *p; 414 struct shmget_args *uap; 415 int mode; 416 int *retval; 417{ 418 int i, segnum, result, shmid, size; 419 struct ucred *cred = p->p_ucred; 420 struct shmid_ds *shmseg; 421 struct shm_handle *shm_handle; 422 423 if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax) 424 return EINVAL; 425 if (shm_nused >= shminfo.shmmni) /* any shmids left? */ 426 return ENOSPC; 427 size = (uap->size + CLOFSET) & ~CLOFSET; 428 if (shm_committed + btoc(size) > shminfo.shmall) 429 return ENOMEM; 430 if (shm_last_free < 0) { 431 for (i = 0; i < shminfo.shmmni; i++) 432 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 433 break; 434 if (i == shminfo.shmmni) 435 panic("shmseg free count inconsistent"); 436 segnum = i; 437 } else { 438 segnum = shm_last_free; 439 shm_last_free = -1; 440 } 441 shmseg = &shmsegs[segnum]; 442 /* 443 * In case we sleep in malloc(), mark the segment present but deleted 444 * so that noone else tries to create the same key. 445 */ 446 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 447 shmseg->shm_perm.key = uap->key; 448 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff; 449 shm_handle = (struct shm_handle *) 450 malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK); 451 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 452 result = vm_mmap(sysvshm_map, &shm_handle->kva, size, VM_PROT_ALL, 453 VM_PROT_DEFAULT, MAP_ANON, (caddr_t) shmid, 0); 454 if (result != KERN_SUCCESS) { 455 shmseg->shm_perm.mode = SHMSEG_FREE; 456 shm_last_free = segnum; 457 free((caddr_t)shm_handle, M_SHM); 458 /* Just in case. */ 459 wakeup((caddr_t)shmseg); 460 return ENOMEM; 461 } 462 shmseg->shm_internal = shm_handle; 463 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 464 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 465 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 466 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 467 shmseg->shm_segsz = uap->size; 468 shmseg->shm_cpid = p->p_pid; 469 shmseg->shm_lpid = shmseg->shm_nattch = 0; 470 shmseg->shm_atime = shmseg->shm_dtime = 0; 471 shmseg->shm_ctime = time.tv_sec; 472 shm_committed += btoc(size); 473 shm_nused++; 474 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 475 /* 476 * Somebody else wanted this key while we were asleep. Wake 477 * them up now. 478 */ 479 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 480 wakeup((caddr_t)shmseg); 481 } 482 *retval = shmid; 483 return 0; 484} 485 486int 487shmget(p, uap, retval) 488 struct proc *p; 489 struct shmget_args *uap; 490 int *retval; 491{ 492 int segnum, mode, error; 493 494 mode = uap->shmflg & ACCESSPERMS; 495 if (uap->key != IPC_PRIVATE) { 496 again: 497 segnum = shm_find_segment_by_key(uap->key); 498 if (segnum >= 0) { 499 error = shmget_existing(p, uap, mode, segnum, retval); 500 if (error == EAGAIN) 501 goto again; 502 return error; 503 } 504 if ((uap->shmflg & IPC_CREAT) == 0) 505 return ENOENT; 506 } 507 return shmget_allocate_segment(p, uap, mode, retval); 508} 509 510struct shmsys_args { 511 u_int which; 512}; 513int 514shmsys(p, uap, retval) 515 struct proc *p; 516 struct shmsys_args *uap; 517 int *retval; 518{ 519 520 if (uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0])) 521 return EINVAL; 522 return ((*shmcalls[uap->which])(p, &uap[1], retval)); 523} 524 525void 526shmfork(p1, p2, isvfork) 527 struct proc *p1, *p2; 528 int isvfork; 529{ 530 struct shmmap_state *shmmap_s; 531 size_t size; 532 int i; 533 534 size = shminfo.shmseg * sizeof(struct shmmap_state); 535 shmmap_s = malloc(size, M_SHM, M_WAITOK); 536 bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size); 537 p2->p_vmspace->vm_shm = (caddr_t)shmmap_s; 538 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 539 if (shmmap_s->shmid != -1) 540 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++; 541} 542 543void 544shmexit(p) 545 struct proc *p; 546{ 547 struct shmmap_state *shmmap_s; 548 int i; 549 550 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 551 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 552 if (shmmap_s->shmid != -1) 553 shm_delete_mapping(p, shmmap_s); 554 free((caddr_t)p->p_vmspace->vm_shm, M_SHM); 555 p->p_vmspace->vm_shm = NULL; 556} 557 558void 559shminit(udata) 560 caddr_t udata; 561{ 562 int i; 563 vm_offset_t garbage1, garbage2; 564 565 /* actually this *should* be pageable. SHM_{LOCK,UNLOCK} */ 566 sysvshm_map = kmem_suballoc(kernel_map, &garbage1, &garbage2, 567 shminfo.shmall * NBPG, TRUE); 568 for (i = 0; i < shminfo.shmmni; i++) { 569 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 570 shmsegs[i].shm_perm.seq = 0; 571 } 572 shm_last_free = 0; 573 shm_nused = 0; 574 shm_committed = 0; 575} 576