sysv_shm.c revision 1.31
1 /* $NetBSD: sysv_shm.c,v 1.31 1995/06/29 11:43:17 cgd 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 /* 54 * Provides the following externally accessible functions: 55 * 56 * shminit(void); initialization 57 * shmexit(struct proc *) cleanup 58 * shmfork(struct proc *, struct proc *, int) fork handling 59 * shmsys(arg1, arg2, arg3, arg4); shm{at,ctl,dt,get}(arg2, arg3, arg4) 60 * 61 * Structures: 62 * shmsegs (an array of 'struct shmid_ds') 63 * per proc array of 'struct shmmap_state' 64 */ 65 66 #define SHMSEG_FREE 0x0200 67 #define SHMSEG_REMOVED 0x0400 68 #define SHMSEG_ALLOCATED 0x0800 69 #define SHMSEG_WANTED 0x1000 70 71 vm_map_t sysvshm_map; 72 int shm_last_free, shm_nused, shm_committed; 73 74 struct shm_handle { 75 vm_offset_t kva; 76 }; 77 78 struct shmmap_state { 79 vm_offset_t va; 80 int shmid; 81 }; 82 83 static void shm_deallocate_segment __P((struct shmid_ds *)); 84 static int shm_find_segment_by_key __P((key_t)); 85 struct shmid_ds *shm_find_segment_by_shmid __P((int)); 86 static int shm_delete_mapping __P((struct proc *, struct shmmap_state *)); 87 88 static int 89 shm_find_segment_by_key(key) 90 key_t key; 91 { 92 int i; 93 94 for (i = 0; i < shminfo.shmmni; i++) 95 if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) && 96 shmsegs[i].shm_perm.key == key) 97 return i; 98 return -1; 99 } 100 101 struct shmid_ds * 102 shm_find_segment_by_shmid(shmid) 103 int shmid; 104 { 105 int segnum; 106 struct shmid_ds *shmseg; 107 108 segnum = IPCID_TO_IX(shmid); 109 if (segnum < 0 || segnum >= shminfo.shmmni) 110 return NULL; 111 shmseg = &shmsegs[segnum]; 112 if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED)) 113 != SHMSEG_ALLOCATED || 114 shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid)) 115 return NULL; 116 return shmseg; 117 } 118 119 static void 120 shm_deallocate_segment(shmseg) 121 struct shmid_ds *shmseg; 122 { 123 struct shm_handle *shm_handle; 124 size_t size; 125 126 shm_handle = shmseg->shm_internal; 127 size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET; 128 vm_deallocate(sysvshm_map, shm_handle->kva, size); 129 free((caddr_t)shm_handle, M_SHM); 130 shmseg->shm_internal = NULL; 131 shm_committed -= btoc(size); 132 shmseg->shm_perm.mode = SHMSEG_FREE; 133 shm_nused--; 134 } 135 136 static int 137 shm_delete_mapping(p, shmmap_s) 138 struct proc *p; 139 struct shmmap_state *shmmap_s; 140 { 141 struct shmid_ds *shmseg; 142 int segnum, result; 143 size_t size; 144 145 segnum = IPCID_TO_IX(shmmap_s->shmid); 146 shmseg = &shmsegs[segnum]; 147 size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET; 148 result = vm_deallocate(&p->p_vmspace->vm_map, shmmap_s->va, size); 149 if (result != KERN_SUCCESS) 150 return EINVAL; 151 shmmap_s->shmid = -1; 152 shmseg->shm_dtime = time.tv_sec; 153 if ((--shmseg->shm_nattch <= 0) && 154 (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { 155 shm_deallocate_segment(shmseg); 156 shm_last_free = segnum; 157 } 158 return 0; 159 } 160 161 int 162 shmdt(p, uap, retval) 163 struct proc *p; 164 struct shmdt_args /* { 165 syscallarg(void *) shmaddr; 166 } */ *uap; 167 register_t *retval; 168 { 169 struct shmmap_state *shmmap_s; 170 int i; 171 172 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 173 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 174 if (shmmap_s->shmid != -1 && 175 shmmap_s->va == (vm_offset_t)SCARG(uap, shmaddr)) 176 break; 177 if (i == shminfo.shmseg) 178 return EINVAL; 179 return shm_delete_mapping(p, shmmap_s); 180 } 181 182 int 183 shmat(p, uap, retval) 184 struct proc *p; 185 struct shmat_args /* { 186 syscallarg(int) shmid; 187 syscallarg(void *) shmaddr; 188 syscallarg(int) shmflag; 189 } */ *uap; 190 register_t *retval; 191 { 192 int error, i, flags; 193 struct ucred *cred = p->p_ucred; 194 struct shmid_ds *shmseg; 195 struct shmmap_state *shmmap_s = NULL; 196 vm_offset_t attach_va; 197 vm_prot_t prot; 198 vm_size_t size; 199 200 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 201 if (shmmap_s == NULL) { 202 size = shminfo.shmseg * sizeof(struct shmmap_state); 203 shmmap_s = malloc(size, M_SHM, M_WAITOK); 204 for (i = 0; i < shminfo.shmseg; i++) 205 shmmap_s[i].shmid = -1; 206 p->p_vmspace->vm_shm = (caddr_t)shmmap_s; 207 } 208 shmseg = shm_find_segment_by_shmid(SCARG(uap, shmid)); 209 if (shmseg == NULL) 210 return EINVAL; 211 if (error = ipcperm(cred, &shmseg->shm_perm, 212 (SCARG(uap, shmflg) & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W)) 213 return error; 214 for (i = 0; i < shminfo.shmseg; i++) { 215 if (shmmap_s->shmid == -1) 216 break; 217 shmmap_s++; 218 } 219 if (i >= shminfo.shmseg) 220 return EMFILE; 221 size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET; 222 prot = VM_PROT_READ; 223 if ((SCARG(uap, shmflg) & SHM_RDONLY) == 0) 224 prot |= VM_PROT_WRITE; 225 flags = MAP_ANON | MAP_SHARED; 226 if (SCARG(uap, shmaddr)) { 227 flags |= MAP_FIXED; 228 if (SCARG(uap, shmflg) & SHM_RND) 229 attach_va = 230 (vm_offset_t)SCARG(uap, shmaddr) & ~(SHMLBA-1); 231 else if (((vm_offset_t)SCARG(uap, shmaddr) & (SHMLBA-1)) == 0) 232 attach_va = (vm_offset_t)SCARG(uap, shmaddr); 233 else 234 return EINVAL; 235 } else { 236 /* This is just a hint to vm_mmap() about where to put it. */ 237 attach_va = 238 round_page(p->p_vmspace->vm_taddr + MAXTSIZ + MAXDSIZ); 239 } 240 error = vm_mmap(&p->p_vmspace->vm_map, &attach_va, size, prot, 241 VM_PROT_DEFAULT, flags, (caddr_t)(long)SCARG(uap, shmid), 0); 242 if (error) 243 return error; 244 shmmap_s->va = attach_va; 245 shmmap_s->shmid = SCARG(uap, shmid); 246 shmseg->shm_lpid = p->p_pid; 247 shmseg->shm_atime = time.tv_sec; 248 shmseg->shm_nattch++; 249 *retval = attach_va; 250 return 0; 251 } 252 253 int 254 shmctl(p, uap, retval) 255 struct proc *p; 256 struct shmctl_args /* { 257 syscallarg(int) shmid; 258 syscallarg(int) cmd; 259 syscallarg(struct shmid_ds *) buf; 260 } */ *uap; 261 register_t *retval; 262 { 263 int error, segnum; 264 struct ucred *cred = p->p_ucred; 265 struct shmid_ds inbuf; 266 struct shmid_ds *shmseg; 267 268 shmseg = shm_find_segment_by_shmid(SCARG(uap, shmid)); 269 if (shmseg == NULL) 270 return EINVAL; 271 switch (SCARG(uap, cmd)) { 272 case IPC_STAT: 273 if (error = ipcperm(cred, &shmseg->shm_perm, IPC_R)) 274 return error; 275 if (error = copyout((caddr_t)shmseg, SCARG(uap, buf), 276 sizeof(inbuf))) 277 return error; 278 break; 279 case IPC_SET: 280 if (error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) 281 return error; 282 if (error = copyin(SCARG(uap, buf), (caddr_t)&inbuf, 283 sizeof(inbuf))) 284 return error; 285 shmseg->shm_perm.uid = inbuf.shm_perm.uid; 286 shmseg->shm_perm.gid = inbuf.shm_perm.gid; 287 shmseg->shm_perm.mode = 288 (shmseg->shm_perm.mode & ~ACCESSPERMS) | 289 (inbuf.shm_perm.mode & ACCESSPERMS); 290 shmseg->shm_ctime = time.tv_sec; 291 break; 292 case IPC_RMID: 293 if (error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) 294 return error; 295 shmseg->shm_perm.key = IPC_PRIVATE; 296 shmseg->shm_perm.mode |= SHMSEG_REMOVED; 297 if (shmseg->shm_nattch <= 0) { 298 shm_deallocate_segment(shmseg); 299 shm_last_free = IPCID_TO_IX(SCARG(uap, shmid)); 300 } 301 break; 302 case SHM_LOCK: 303 case SHM_UNLOCK: 304 default: 305 return EINVAL; 306 } 307 return 0; 308 } 309 310 static int 311 shmget_existing(p, uap, mode, segnum, retval) 312 struct proc *p; 313 struct shmget_args /* { 314 syscallarg(key_t) key; 315 syscallarg(int) size; 316 syscallarg(int) shmflag; 317 } */ *uap; 318 int mode; 319 int segnum; 320 register_t *retval; 321 { 322 struct shmid_ds *shmseg; 323 struct ucred *cred = p->p_ucred; 324 int error; 325 326 shmseg = &shmsegs[segnum]; 327 if (shmseg->shm_perm.mode & SHMSEG_REMOVED) { 328 /* 329 * This segment is in the process of being allocated. Wait 330 * until it's done, and look the key up again (in case the 331 * allocation failed or it was freed). 332 */ 333 shmseg->shm_perm.mode |= SHMSEG_WANTED; 334 if (error = 335 tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0)) 336 return error; 337 return EAGAIN; 338 } 339 if (error = ipcperm(cred, &shmseg->shm_perm, mode)) 340 return error; 341 if (SCARG(uap, size) && SCARG(uap, size) > shmseg->shm_segsz) 342 return EINVAL; 343 if (SCARG(uap, shmflg) & (IPC_CREAT | IPC_EXCL) == 344 (IPC_CREAT | IPC_EXCL)) 345 return EEXIST; 346 *retval = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 347 return 0; 348 } 349 350 static int 351 shmget_allocate_segment(p, uap, mode, retval) 352 struct proc *p; 353 struct shmget_args /* { 354 syscallarg(key_t) key; 355 syscallarg(int) size; 356 syscallarg(int) shmflag; 357 } */ *uap; 358 int mode; 359 register_t *retval; 360 { 361 int i, segnum, result, shmid, size; 362 struct ucred *cred = p->p_ucred; 363 struct shmid_ds *shmseg; 364 struct shm_handle *shm_handle; 365 366 if (SCARG(uap, size) < shminfo.shmmin || 367 SCARG(uap, size) > shminfo.shmmax) 368 return EINVAL; 369 if (shm_nused >= shminfo.shmmni) /* any shmids left? */ 370 return ENOSPC; 371 size = (SCARG(uap, size) + CLOFSET) & ~CLOFSET; 372 if (shm_committed + btoc(size) > shminfo.shmall) 373 return ENOMEM; 374 if (shm_last_free < 0) { 375 for (i = 0; i < shminfo.shmmni; i++) 376 if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) 377 break; 378 if (i == shminfo.shmmni) 379 panic("shmseg free count inconsistent"); 380 segnum = i; 381 } else { 382 segnum = shm_last_free; 383 shm_last_free = -1; 384 } 385 shmseg = &shmsegs[segnum]; 386 /* 387 * In case we sleep in malloc(), mark the segment present but deleted 388 * so that noone else tries to create the same key. 389 */ 390 shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED; 391 shmseg->shm_perm.key = SCARG(uap, key); 392 shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff; 393 shm_handle = (struct shm_handle *) 394 malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK); 395 shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); 396 result = vm_mmap(sysvshm_map, &shm_handle->kva, size, VM_PROT_ALL, 397 VM_PROT_DEFAULT, MAP_ANON, (caddr_t)(long)shmid, 0); 398 if (result != KERN_SUCCESS) { 399 shmseg->shm_perm.mode = SHMSEG_FREE; 400 shm_last_free = segnum; 401 free((caddr_t)shm_handle, M_SHM); 402 /* Just in case. */ 403 wakeup((caddr_t)shmseg); 404 return ENOMEM; 405 } 406 shmseg->shm_internal = shm_handle; 407 shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid; 408 shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid; 409 shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | 410 (mode & ACCESSPERMS) | SHMSEG_ALLOCATED; 411 shmseg->shm_segsz = SCARG(uap, size); 412 shmseg->shm_cpid = p->p_pid; 413 shmseg->shm_lpid = shmseg->shm_nattch = 0; 414 shmseg->shm_atime = shmseg->shm_dtime = 0; 415 shmseg->shm_ctime = time.tv_sec; 416 shm_committed += btoc(size); 417 shm_nused++; 418 if (shmseg->shm_perm.mode & SHMSEG_WANTED) { 419 /* 420 * Somebody else wanted this key while we were asleep. Wake 421 * them up now. 422 */ 423 shmseg->shm_perm.mode &= ~SHMSEG_WANTED; 424 wakeup((caddr_t)shmseg); 425 } 426 *retval = shmid; 427 return 0; 428 } 429 430 int 431 shmget(p, uap, retval) 432 struct proc *p; 433 struct shmget_args /* { 434 syscallarg(key_t) key; 435 syscallarg(int) size; 436 syscallarg(int) shmflag; 437 } */ *uap; 438 register_t *retval; 439 { 440 int segnum, mode, error; 441 struct shmid_ds *shmseg; 442 443 mode = SCARG(uap, shmflg) & ACCESSPERMS; 444 if (SCARG(uap, key) != IPC_PRIVATE) { 445 again: 446 segnum = shm_find_segment_by_key(SCARG(uap, key)); 447 if (segnum >= 0) { 448 error = shmget_existing(p, uap, mode, segnum, retval); 449 if (error == EAGAIN) 450 goto again; 451 return error; 452 } 453 if ((SCARG(uap, shmflg) & IPC_CREAT) == 0) 454 return ENOENT; 455 } 456 return shmget_allocate_segment(p, uap, mode, retval); 457 } 458 459 void 460 shmfork(p1, p2, isvfork) 461 struct proc *p1, *p2; 462 int isvfork; 463 { 464 struct shmmap_state *shmmap_s; 465 size_t size; 466 int i; 467 468 size = shminfo.shmseg * sizeof(struct shmmap_state); 469 shmmap_s = malloc(size, M_SHM, M_WAITOK); 470 bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size); 471 p2->p_vmspace->vm_shm = (caddr_t)shmmap_s; 472 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 473 if (shmmap_s->shmid != -1) 474 shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++; 475 } 476 477 void 478 shmexit(p) 479 struct proc *p; 480 { 481 struct shmmap_state *shmmap_s; 482 struct shmid_ds *shmseg; 483 int i; 484 485 shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; 486 for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) 487 if (shmmap_s->shmid != -1) 488 shm_delete_mapping(p, shmmap_s); 489 free((caddr_t)p->p_vmspace->vm_shm, M_SHM); 490 p->p_vmspace->vm_shm = NULL; 491 } 492 493 void 494 shminit() 495 { 496 int i; 497 vm_offset_t garbage1, garbage2; 498 499 shminfo.shmmax *= NBPG; 500 501 /* actually this *should* be pageable. SHM_{LOCK,UNLOCK} */ 502 sysvshm_map = kmem_suballoc(kernel_map, &garbage1, &garbage2, 503 shminfo.shmall * NBPG, TRUE); 504 for (i = 0; i < shminfo.shmmni; i++) { 505 shmsegs[i].shm_perm.mode = SHMSEG_FREE; 506 shmsegs[i].shm_perm.seq = 0; 507 } 508 shm_last_free = 0; 509 shm_nused = 0; 510 shm_committed = 0; 511 } 512
Indexes created Fri Sep 26 08:10:20 GMT 2025