sysv_shm.c revision 1.35
1 /* $NetBSD: sysv_shm.c,v 1.35 1996/02/04 02:17:10 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1994 Adam Glass and Charles Hannum. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by Adam Glass and Charles 17 * Hannum. 18 * 4. The names of the authors may not be used to endorse or promote products 19 * derived from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 #include <sys/types.h> 34 #include <sys/param.h> 35 #include <sys/kernel.h> 36 #include <sys/shm.h> 37 #include <sys/proc.h> 38 #include <sys/uio.h> 39 #include <sys/time.h> 40 #include <sys/malloc.h> 41 #include <sys/mman.h> 42 #include <sys/systm.h> 43 #include <sys/stat.h> 44 45 #include <sys/mount.h> 46 #include <sys/syscallargs.h> 47 48 #include <vm/vm.h> 49 #include <vm/vm_map.h> 50 #include <vm/vm_map.h> 51 #include <vm/vm_kern.h> 52 53 #include <kern/kern_extern.h> 54 55 struct shmid_ds *shm_find_segment_by_shmid __P((int)); 56 void shmexit __P((struct proc *)); 57 58 /* 59 * Provides the following externally accessible functions: 60 * 61 * shminit(void); initialization 62 * shmexit(struct proc *) cleanup 63 * shmfork(struct proc *, struct proc *) fork handling 64 * shmsys(arg1, arg2, arg3, arg4); shm{at,ctl,dt,get}(arg2, arg3, arg4) 65 * 66 * Structures: 67 * shmsegs (an array of 'struct shmid_ds') 68 * per proc array of 'struct shmmap_state' 69 */ 70 71 #define SHMSEG_FREE 0x0200 72 #define SHMSEG_REMOVED 0x0400 73 #define SHMSEG_ALLOCATED 0x0800 74 #define SHMSEG_WANTED 0x1000 75 76 vm_map_t sysvshm_map; 77 int shm_last_free, shm_nused, shm_committed; 78 79 struct shm_handle { 80 vm_offset_t kva; 81 }; 82 83 struct shmmap_state { 84 vm_offset_t va; 85 int shmid; 86 }; 87 88 static int shm_find_segment_by_key __P((key_t)); 89 static void shm_deallocate_segment __P((struct shmid_ds *)); 90 static int shm_delete_mapping __P((struct proc *, struct shmmap_state *)); 91 static int shmget_existing __P((struct proc *, struct sys_shmget_args *, 92 int, int, register_t *)); 93 static int shmget_allocate_segment __P((struct proc *, struct sys_shmget_args *, 94 int, register_t *)); 95 96 static int 97 shm_find_segment_by_key(key) 98 key_t key; 99 { 100 int i; 101 102 for (i = 0; i < shminfo.shmmni; i++) 103 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) && 104 shmsegs[i].shm_perm.key == key) 105 return i; 106 return -1; 107 } 108 109 struct shmid_ds * 110 shm_find_segment_by_shmid(shmid) 111 int shmid; 112 { 113 int segnum; 114 struct shmid_ds *shmseg; 115 116 segnum = IPCID_TO_IX(shmid); 117 if (segnum < 0 || segnum >= shminfo.shmmni) 118 return NULL; 119 shmseg = &shmsegs[segnum]; 120 if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED)) 121 != SHMSEG_ALLOCATED || 122 shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid)) 123 return NULL; 124 return shmseg; 125 } 126 127 static void 128 shm_deallocate_segment(shmseg) 129 struct shmid_ds *shmseg; 130 { 131 struct shm_handle *shm_handle; 132 size_t size; 133 134 shm_handle = shmseg->shm_internal; 135 size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET; 136 vm_deallocate(sysvshm_map, shm_handle->kva, size); 137 free((caddr_t)shm_handle, M_SHM); 138 shmseg->shm_internal = NULL; 139 shm_committed -= btoc(size); 140 shmseg->shm_perm.mode = SHMSEG_FREE; 141 shm_nused--; 142 } 143 144 static int 145 shm_delete_mapping(p, shmmap_s) 146 struct proc *p; 147 struct shmmap_state *shmmap_s; 148 { 149 struct shmid_ds *shmseg; 150 int segnum, result; 151 size_t size; 152 153 segnum = IPCID_TO_IX(shmmap_s->shmid); 154 shmseg = &shmsegs[segnum]; 155 size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET; 156 result = vm_deallocate(&p->p_vmspace->vm_map, shmmap_s->va, size); 157 if (result != KERN_SUCCESS) 158 return EINVAL; 159 shmmap_s->shmid = -1; 160 shmseg->shm_dtime = time.tv_sec; 161 if ((--shmseg->shm_nattch <= 0) && 162 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { 163 shm_deallocate_segment(shmseg); 164 shm_last_free = segnum; 165 } 166 return 0; 167 } 168 169 int 170 sys_shmdt(p, v, retval) 171 struct proc *p; 172 void *v; 173 register_t *retval; 174 { 175 struct sys_shmdt_args /* { 176 syscallarg(void *) shmaddr; 177 } */ *uap = v; 178 struct shmmap_state *shmmap_s; 179 int i; 180 181 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 182 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 183 if (shmmap_s->shmid != -1 && 184 shmmap_s->va == (vm_offset_t)SCARG(uap, shmaddr)) 185 break; 186 if (i == shminfo.shmseg) 187 return EINVAL; 188 return shm_delete_mapping(p, shmmap_s); 189 } 190 191 int 192 sys_shmat(p, v, retval) 193 struct proc *p; 194 void *v; 195 register_t *retval; 196 { 197 struct sys_shmat_args /* { 198 syscallarg(int) shmid; 199 syscallarg(void *) shmaddr; 200 syscallarg(int) shmflg; 201 } */ *uap = v; 202 int error, i, flags; 203 struct ucred *cred = p->p_ucred; 204 struct shmid_ds *shmseg; 205 struct shmmap_state *shmmap_s = NULL; 206 vm_offset_t attach_va; 207 vm_prot_t prot; 208 vm_size_t size; 209 210 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 211 if (shmmap_s == NULL) { 212 size = shminfo.shmseg * sizeof(struct shmmap_state); 213 shmmap_s = malloc(size, M_SHM, M_WAITOK); 214 for (i = 0; i < shminfo.shmseg; i++) 215 shmmap_s[i].shmid = -1; 216 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 217 } 218 shmseg = shm_find_segment_by_shmid(SCARG(uap, shmid)); 219 if (shmseg == NULL) 220 return EINVAL; 221 error = ipcperm(cred, &shmseg->shm_perm, 222 (SCARG(uap, shmflg) & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W); 223 if (error) 224 return error; 225 for (i = 0; i < shminfo.shmseg; i++) { 226 if (shmmap_s->shmid == -1) 227 break; 228 shmmap_s++; 229 } 230 if (i >= shminfo.shmseg) 231 return EMFILE; 232 size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET; 233 prot = VM_PROT_READ; 234 if ((SCARG(uap, shmflg) & SHM_RDONLY) == 0) 235 prot |= VM_PROT_WRITE; 236 flags = MAP_ANON | MAP_SHARED; 237 if (SCARG(uap, shmaddr)) { 238 flags |= MAP_FIXED; 239 if (SCARG(uap, shmflg) & SHM_RND) 240 attach_va = 241 (vm_offset_t)SCARG(uap, shmaddr) & ~(SHMLBA-1); 242 else if (((vm_offset_t)SCARG(uap, shmaddr) & (SHMLBA-1)) == 0) 243 attach_va = (vm_offset_t)SCARG(uap, shmaddr); 244 else 245 return EINVAL; 246 } else { 247 /* This is just a hint to vm_mmap() about where to put it. */ 248 attach_va = 249 round_page(p->p_vmspace->vm_taddr + MAXTSIZ + MAXDSIZ); 250 } 251 error = vm_mmap(&p->p_vmspace->vm_map, &attach_va, size, prot, 252 VM_PROT_DEFAULT, flags, (caddr_t)(long)SCARG(uap, shmid), 0); 253 if (error) 254 return error; 255 shmmap_s->va = attach_va; 256 shmmap_s->shmid = SCARG(uap, shmid); 257 shmseg->shm_lpid = p->p_pid; 258 shmseg->shm_atime = time.tv_sec; 259 shmseg->shm_nattch++; 260 *retval = attach_va; 261 return 0; 262 } 263 264 int 265 sys_shmctl(p, v, retval) 266 struct proc *p; 267 void *v; 268 register_t *retval; 269 { 270 struct sys_shmctl_args /* { 271 syscallarg(int) shmid; 272 syscallarg(int) cmd; 273 syscallarg(struct shmid_ds *) buf; 274 } */ *uap = v; 275 int error; 276 struct ucred *cred = p->p_ucred; 277 struct shmid_ds inbuf; 278 struct shmid_ds *shmseg; 279 280 shmseg = shm_find_segment_by_shmid(SCARG(uap, shmid)); 281 if (shmseg == NULL) 282 return EINVAL; 283 switch (SCARG(uap, cmd)) { 284 case IPC_STAT: 285 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_R)) != 0) 286 return error; 287 error = copyout((caddr_t)shmseg, SCARG(uap, buf), 288 sizeof(inbuf)); 289 if (error) 290 return error; 291 break; 292 case IPC_SET: 293 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) 294 return error; 295 error = copyin(SCARG(uap, buf), (caddr_t)&inbuf, 296 sizeof(inbuf)); 297 if (error) 298 return error; 299 shmseg->shm_perm.uid = inbuf.shm_perm.uid; 300 shmseg->shm_perm.gid = inbuf.shm_perm.gid; 301 shmseg->shm_perm.mode = 302 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 303 (inbuf.shm_perm.mode & ACCESSPERMS); 304 shmseg->shm_ctime = time.tv_sec; 305 break; 306 case IPC_RMID: 307 if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) 308 return error; 309 shmseg->shm_perm.key = IPC_PRIVATE; 310 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 311 if (shmseg->shm_nattch <= 0) { 312 shm_deallocate_segment(shmseg); 313 shm_last_free = IPCID_TO_IX(SCARG(uap, shmid)); 314 } 315 break; 316 case SHM_LOCK: 317 case SHM_UNLOCK: 318 default: 319 return EINVAL; 320 } 321 return 0; 322 } 323 324 static int 325 shmget_existing(p, uap, mode, segnum, retval) 326 struct proc *p; 327 struct sys_shmget_args /* { 328 syscallarg(key_t) key; 329 syscallarg(int) size; 330 syscallarg(int) shmflg; 331 } */ *uap; 332 int mode; 333 int segnum; 334 register_t *retval; 335 { 336 struct shmid_ds *shmseg; 337 struct ucred *cred = p->p_ucred; 338 int error; 339 340 shmseg = &shmsegs[segnum]; 341 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 342 /* 343 * This segment is in the process of being allocated. Wait 344 * until it's done, and look the key up again (in case the 345 * allocation failed or it was freed). 346 */ 347 shmseg->shm_perm.mode |= SHMSEG_WANTED; 348 error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0); 349 if (error) 350 return error; 351 return EAGAIN; 352 } 353 if ((error = ipcperm(cred, &shmseg->shm_perm, mode)) != 0) 354 return error; 355 if (SCARG(uap, size) && SCARG(uap, size) > shmseg->shm_segsz) 356 return EINVAL; 357 if (SCARG(uap, shmflg) & (IPC_CREAT | IPC_EXCL) == 358 (IPC_CREAT | IPC_EXCL)) 359 return EEXIST; 360 *retval = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 361 return 0; 362 } 363 364 static int 365 shmget_allocate_segment(p, uap, mode, retval) 366 struct proc *p; 367 struct sys_shmget_args /* { 368 syscallarg(key_t) key; 369 syscallarg(int) size; 370 syscallarg(int) shmflg; 371 } */ *uap; 372 int mode; 373 register_t *retval; 374 { 375 int i, segnum, result, shmid, size; 376 struct ucred *cred = p->p_ucred; 377 struct shmid_ds *shmseg; 378 struct shm_handle *shm_handle; 379 380 if (SCARG(uap, size) < shminfo.shmmin || 381 SCARG(uap, size) > shminfo.shmmax) 382 return EINVAL; 383 if (shm_nused >= shminfo.shmmni) /* any shmids left? */ 384 return ENOSPC; 385 size = (SCARG(uap, size) + CLOFSET) & ~CLOFSET; 386 if (shm_committed + btoc(size) > shminfo.shmall) 387 return ENOMEM; 388 if (shm_last_free < 0) { 389 for (i = 0; i < shminfo.shmmni; i++) 390 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 391 break; 392 if (i == shminfo.shmmni) 393 panic("shmseg free count inconsistent"); 394 segnum = i; 395 } else { 396 segnum = shm_last_free; 397 shm_last_free = -1; 398 } 399 shmseg = &shmsegs[segnum]; 400 /* 401 * In case we sleep in malloc(), mark the segment present but deleted 402 * so that noone else tries to create the same key. 403 */ 404 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 405 shmseg->shm_perm.key = SCARG(uap, key); 406 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff; 407 shm_handle = (struct shm_handle *) 408 malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK); 409 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 410 result = vm_mmap(sysvshm_map, &shm_handle->kva, size, VM_PROT_ALL, 411 VM_PROT_DEFAULT, MAP_ANON, (caddr_t)(long)shmid, 0); 412 if (result != KERN_SUCCESS) { 413 shmseg->shm_perm.mode = SHMSEG_FREE; 414 shm_last_free = segnum; 415 free((caddr_t)shm_handle, M_SHM); 416 /* Just in case. */ 417 wakeup((caddr_t)shmseg); 418 return ENOMEM; 419 } 420 shmseg->shm_internal = shm_handle; 421 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 422 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 423 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 424 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 425 shmseg->shm_segsz = SCARG(uap, size); 426 shmseg->shm_cpid = p->p_pid; 427 shmseg->shm_lpid = shmseg->shm_nattch = 0; 428 shmseg->shm_atime = shmseg->shm_dtime = 0; 429 shmseg->shm_ctime = time.tv_sec; 430 shm_committed += btoc(size); 431 shm_nused++; 432 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 433 /* 434 * Somebody else wanted this key while we were asleep. Wake 435 * them up now. 436 */ 437 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 438 wakeup((caddr_t)shmseg); 439 } 440 *retval = shmid; 441 return 0; 442 } 443 444 int 445 sys_shmget(p, v, retval) 446 struct proc *p; 447 void *v; 448 register_t *retval; 449 { 450 struct sys_shmget_args /* { 451 syscallarg(key_t) key; 452 syscallarg(int) size; 453 syscallarg(int) shmflg; 454 } */ *uap = v; 455 int segnum, mode, error; 456 457 mode = SCARG(uap, shmflg) & ACCESSPERMS; 458 if (SCARG(uap, key) != IPC_PRIVATE) { 459 again: 460 segnum = shm_find_segment_by_key(SCARG(uap, key)); 461 if (segnum >= 0) { 462 error = shmget_existing(p, uap, mode, segnum, retval); 463 if (error == EAGAIN) 464 goto again; 465 return error; 466 } 467 if ((SCARG(uap, shmflg) & IPC_CREAT) == 0) 468 return ENOENT; 469 } 470 return shmget_allocate_segment(p, uap, mode, retval); 471 } 472 473 void 474 shmfork(p1, p2) 475 struct proc *p1, *p2; 476 { 477 struct shmmap_state *shmmap_s; 478 size_t size; 479 int i; 480 481 size = shminfo.shmseg * sizeof(struct shmmap_state); 482 shmmap_s = malloc(size, M_SHM, M_WAITOK); 483 bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size); 484 p2->p_vmspace->vm_shm = (caddr_t)shmmap_s; 485 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 486 if (shmmap_s->shmid != -1) 487 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++; 488 } 489 490 void 491 shmexit(p) 492 struct proc *p; 493 { 494 struct shmmap_state *shmmap_s; 495 int i; 496 497 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 498 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 499 if (shmmap_s->shmid != -1) 500 shm_delete_mapping(p, shmmap_s); 501 free((caddr_t)p->p_vmspace->vm_shm, M_SHM); 502 p->p_vmspace->vm_shm = NULL; 503 } 504 505 void 506 shminit() 507 { 508 int i; 509 vm_offset_t garbage1, garbage2; 510 511 shminfo.shmmax *= NBPG; 512 513 /* actually this *should* be pageable. SHM_{LOCK,UNLOCK} */ 514 sysvshm_map = kmem_suballoc(kernel_map, &garbage1, &garbage2, 515 shminfo.shmall * NBPG, TRUE); 516 for (i = 0; i < shminfo.shmmni; i++) { 517 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 518 shmsegs[i].shm_perm.seq = 0; 519 } 520 shm_last_free = 0; 521 shm_nused = 0; 522 shm_committed = 0; 523 } 524
Indexes created Mon Sep 22 13:09:51 GMT 2025