1 /* $NetBSD: sysv_msg.c,v 1.56 2008/04/28 20:24:05 martin Exp $ */ 2 3 /*- 4 * Copyright (c) 1999, 2006, 2007 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 9 * NASA Ames Research Center, and by Andrew Doran. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 /* 34 * Implementation of SVID messages 35 * 36 * Author: Daniel Boulet 37 * 38 * Copyright 1993 Daniel Boulet and RTMX Inc. 39 * 40 * This system call was implemented by Daniel Boulet under contract from RTMX. 41 * 42 * Redistribution and use in source forms, with and without modification, 43 * are permitted provided that this entire comment appears intact. 44 * 45 * Redistribution in binary form may occur without any restrictions. 46 * Obviously, it would be nice if you gave credit where credit is due 47 * but requiring it would be too onerous. 48 * 49 * This software is provided ``AS IS'' without any warranties of any kind. 50 */ 51 52 #include <sys/cdefs.h> 53 __KERNEL_RCSID(0, "$NetBSD: sysv_msg.c,v 1.56 2008/04/28 20:24:05 martin Exp $"); 54 55 #define SYSVMSG 56 57 #include <sys/param.h> 58 #include <sys/kernel.h> 59 #include <sys/msg.h> 60 #include <sys/sysctl.h> 61 #include <sys/mount.h> /* XXX for <sys/syscallargs.h> */ 62 #include <sys/syscallargs.h> 63 #include <sys/kauth.h> 64 65 #define MSG_DEBUG 66 #undef MSG_DEBUG_OK 67 68 #ifdef MSG_DEBUG_OK 69 #define MSG_PRINTF(a) printf a 70 #else 71 #define MSG_PRINTF(a) 72 #endif 73 74 static int nfree_msgmaps; /* # of free map entries */ 75 static short free_msgmaps; /* head of linked list of free map entries */ 76 static struct __msg *free_msghdrs; /* list of free msg headers */ 77 static char *msgpool; /* MSGMAX byte long msg buffer pool */ 78 static struct msgmap *msgmaps; /* MSGSEG msgmap structures */ 79 static struct __msg *msghdrs; /* MSGTQL msg headers */ 80 81 kmsq_t *msqs; /* MSGMNI msqid_ds struct's */ 82 kmutex_t msgmutex; /* subsystem lock */ 83 84 static u_int msg_waiters = 0; /* total number of msgrcv waiters */ 85 static bool msg_realloc_state; 86 static kcondvar_t msg_realloc_cv; 87 88 static void msg_freehdr(struct __msg *); 89 90 void 91 msginit(void) 92 { 93 int i, sz; 94 vaddr_t v; 95 96 /* 97 * msginfo.msgssz should be a power of two for efficiency reasons. 98 * It is also pretty silly if msginfo.msgssz is less than 8 99 * or greater than about 256 so ... 100 */ 101 102 i = 8; 103 while (i < 1024 && i != msginfo.msgssz) 104 i <<= 1; 105 if (i != msginfo.msgssz) { 106 panic("msginfo.msgssz = %d, not a small power of 2", 107 msginfo.msgssz); 108 } 109 110 if (msginfo.msgseg > 32767) { 111 panic("msginfo.msgseg = %d > 32767", msginfo.msgseg); 112 } 113 114 /* Allocate the wired memory for our structures */ 115 sz = ALIGN(msginfo.msgmax) + 116 ALIGN(msginfo.msgseg * sizeof(struct msgmap)) + 117 ALIGN(msginfo.msgtql * sizeof(struct __msg)) + 118 ALIGN(msginfo.msgmni * sizeof(kmsq_t)); 119 v = uvm_km_alloc(kernel_map, round_page(sz), 0, 120 UVM_KMF_WIRED|UVM_KMF_ZERO); 121 if (v == 0) 122 panic("sysv_msg: cannot allocate memory"); 123 msgpool = (void *)v; 124 msgmaps = (void *)(ALIGN(msgpool) + msginfo.msgmax); 125 msghdrs = (void *)(ALIGN(msgmaps) + 126 msginfo.msgseg * sizeof(struct msgmap)); 127 msqs = (void *)(ALIGN(msghdrs) + 128 msginfo.msgtql * sizeof(struct __msg)); 129 130 for (i = 0; i < (msginfo.msgseg - 1); i++) 131 msgmaps[i].next = i + 1; 132 msgmaps[msginfo.msgseg - 1].next = -1; 133 134 free_msgmaps = 0; 135 nfree_msgmaps = msginfo.msgseg; 136 137 for (i = 0; i < (msginfo.msgtql - 1); i++) { 138 msghdrs[i].msg_type = 0; 139 msghdrs[i].msg_next = &msghdrs[i + 1]; 140 } 141 i = msginfo.msgtql - 1; 142 msghdrs[i].msg_type = 0; 143 msghdrs[i].msg_next = NULL; 144 free_msghdrs = &msghdrs[0]; 145 146 for (i = 0; i < msginfo.msgmni; i++) { 147 cv_init(&msqs[i].msq_cv, "msgwait"); 148 /* Implies entry is available */ 149 msqs[i].msq_u.msg_qbytes = 0; 150 /* Reset to a known value */ 151 msqs[i].msq_u.msg_perm._seq = 0; 152 } 153 154 mutex_init(&msgmutex, MUTEX_DEFAULT, IPL_NONE); 155 cv_init(&msg_realloc_cv, "msgrealc"); 156 msg_realloc_state = false; 157 } 158 159 static int 160 msgrealloc(int newmsgmni, int newmsgseg) 161 { 162 struct msgmap *new_msgmaps; 163 struct __msg *new_msghdrs, *new_free_msghdrs; 164 char *old_msgpool, *new_msgpool; 165 kmsq_t *new_msqs; 166 vaddr_t v; 167 int i, sz, msqid, newmsgmax, new_nfree_msgmaps; 168 short new_free_msgmaps; 169 170 if (newmsgmni < 1 || newmsgseg < 1) 171 return EINVAL; 172 173 /* Allocate the wired memory for our structures */ 174 newmsgmax = msginfo.msgssz * newmsgseg; 175 sz = ALIGN(newmsgmax) + 176 ALIGN(newmsgseg * sizeof(struct msgmap)) + 177 ALIGN(msginfo.msgtql * sizeof(struct __msg)) + 178 ALIGN(newmsgmni * sizeof(kmsq_t)); 179 v = uvm_km_alloc(kernel_map, round_page(sz), 0, 180 UVM_KMF_WIRED|UVM_KMF_ZERO); 181 if (v == 0) 182 return ENOMEM; 183 184 mutex_enter(&msgmutex); 185 if (msg_realloc_state) { 186 mutex_exit(&msgmutex); 187 uvm_km_free(kernel_map, v, sz, UVM_KMF_WIRED); 188 return EBUSY; 189 } 190 msg_realloc_state = true; 191 if (msg_waiters) { 192 /* 193 * Mark reallocation state, wake-up all waiters, 194 * and wait while they will all exit. 195 */ 196 for (i = 0; i < msginfo.msgmni; i++) 197 cv_broadcast(&msqs[i].msq_cv); 198 while (msg_waiters) 199 cv_wait(&msg_realloc_cv, &msgmutex); 200 } 201 old_msgpool = msgpool; 202 203 /* We cannot reallocate less memory than we use */ 204 i = 0; 205 for (msqid = 0; msqid < msginfo.msgmni; msqid++) { 206 struct msqid_ds *mptr; 207 kmsq_t *msq; 208 209 msq = &msqs[msqid]; 210 mptr = &msq->msq_u; 211 if (mptr->msg_qbytes || (mptr->msg_perm.mode & MSG_LOCKED)) 212 i = msqid; 213 } 214 if (i >= newmsgmni || (msginfo.msgseg - nfree_msgmaps) > newmsgseg) { 215 mutex_exit(&msgmutex); 216 uvm_km_free(kernel_map, v, sz, UVM_KMF_WIRED); 217 return EBUSY; 218 } 219 220 new_msgpool = (void *)v; 221 new_msgmaps = (void *)(ALIGN(new_msgpool) + newmsgmax); 222 new_msghdrs = (void *)(ALIGN(new_msgmaps) + 223 newmsgseg * sizeof(struct msgmap)); 224 new_msqs = (void *)(ALIGN(new_msghdrs) + 225 msginfo.msgtql * sizeof(struct __msg)); 226 227 /* Initialize the structures */ 228 for (i = 0; i < (newmsgseg - 1); i++) 229 new_msgmaps[i].next = i + 1; 230 new_msgmaps[newmsgseg - 1].next = -1; 231 new_free_msgmaps = 0; 232 new_nfree_msgmaps = newmsgseg; 233 234 for (i = 0; i < (msginfo.msgtql - 1); i++) { 235 new_msghdrs[i].msg_type = 0; 236 new_msghdrs[i].msg_next = &new_msghdrs[i + 1]; 237 } 238 i = msginfo.msgtql - 1; 239 new_msghdrs[i].msg_type = 0; 240 new_msghdrs[i].msg_next = NULL; 241 new_free_msghdrs = &new_msghdrs[0]; 242 243 for (i = 0; i < newmsgmni; i++) { 244 new_msqs[i].msq_u.msg_qbytes = 0; 245 new_msqs[i].msq_u.msg_perm._seq = 0; 246 cv_init(&new_msqs[i].msq_cv, "msgwait"); 247 } 248 249 /* 250 * Copy all message queue identifiers, mesage headers and buffer 251 * pools to the new memory location. 252 */ 253 for (msqid = 0; msqid < msginfo.msgmni; msqid++) { 254 struct __msg *nmsghdr, *msghdr, *pmsghdr; 255 struct msqid_ds *nmptr, *mptr; 256 kmsq_t *nmsq, *msq; 257 258 msq = &msqs[msqid]; 259 mptr = &msq->msq_u; 260 261 if (mptr->msg_qbytes == 0 && 262 (mptr->msg_perm.mode & MSG_LOCKED) == 0) 263 continue; 264 265 nmsq = &new_msqs[msqid]; 266 nmptr = &nmsq->msq_u; 267 memcpy(nmptr, mptr, sizeof(struct msqid_ds)); 268 269 /* 270 * Go through the message headers, and and copy each 271 * one by taking the new ones, and thus defragmenting. 272 */ 273 nmsghdr = pmsghdr = NULL; 274 msghdr = mptr->_msg_first; 275 while (msghdr) { 276 short nnext = 0, next; 277 u_short msgsz, segcnt; 278 279 /* Take an entry from the new list of free msghdrs */ 280 nmsghdr = new_free_msghdrs; 281 KASSERT(nmsghdr != NULL); 282 new_free_msghdrs = nmsghdr->msg_next; 283 284 nmsghdr->msg_next = NULL; 285 if (pmsghdr) { 286 pmsghdr->msg_next = nmsghdr; 287 } else { 288 nmptr->_msg_first = nmsghdr; 289 pmsghdr = nmsghdr; 290 } 291 nmsghdr->msg_ts = msghdr->msg_ts; 292 nmsghdr->msg_spot = -1; 293 294 /* Compute the amount of segments and reserve them */ 295 msgsz = msghdr->msg_ts; 296 segcnt = (msgsz + msginfo.msgssz - 1) / msginfo.msgssz; 297 if (segcnt == 0) 298 continue; 299 while (segcnt--) { 300 nnext = new_free_msgmaps; 301 new_free_msgmaps = new_msgmaps[nnext].next; 302 new_nfree_msgmaps--; 303 new_msgmaps[nnext].next = nmsghdr->msg_spot; 304 nmsghdr->msg_spot = nnext; 305 } 306 307 /* Copy all segments */ 308 KASSERT(nnext == nmsghdr->msg_spot); 309 next = msghdr->msg_spot; 310 while (msgsz > 0) { 311 size_t tlen; 312 313 if (msgsz >= msginfo.msgssz) { 314 tlen = msginfo.msgssz; 315 msgsz -= msginfo.msgssz; 316 } else { 317 tlen = msgsz; 318 msgsz = 0; 319 } 320 321 /* Copy the message buffer */ 322 memcpy(&new_msgpool[nnext * msginfo.msgssz], 323 &msgpool[next * msginfo.msgssz], tlen); 324 325 /* Next entry of the map */ 326 nnext = msgmaps[nnext].next; 327 next = msgmaps[next].next; 328 } 329 330 /* Next message header */ 331 msghdr = msghdr->msg_next; 332 } 333 nmptr->_msg_last = nmsghdr; 334 } 335 KASSERT((msginfo.msgseg - nfree_msgmaps) == 336 (newmsgseg - new_nfree_msgmaps)); 337 338 sz = ALIGN(msginfo.msgmax) + 339 ALIGN(msginfo.msgseg * sizeof(struct msgmap)) + 340 ALIGN(msginfo.msgtql * sizeof(struct __msg)) + 341 ALIGN(msginfo.msgmni * sizeof(kmsq_t)); 342 343 for (i = 0; i < msginfo.msgmni; i++) 344 cv_destroy(&msqs[i].msq_cv); 345 346 /* Set the pointers and update the new values */ 347 msgpool = new_msgpool; 348 msgmaps = new_msgmaps; 349 msghdrs = new_msghdrs; 350 msqs = new_msqs; 351 352 free_msghdrs = new_free_msghdrs; 353 free_msgmaps = new_free_msgmaps; 354 nfree_msgmaps = new_nfree_msgmaps; 355 msginfo.msgmni = newmsgmni; 356 msginfo.msgseg = newmsgseg; 357 msginfo.msgmax = newmsgmax; 358 359 /* Reallocation completed - notify all waiters, if any */ 360 msg_realloc_state = false; 361 cv_broadcast(&msg_realloc_cv); 362 mutex_exit(&msgmutex); 363 364 uvm_km_free(kernel_map, (vaddr_t)old_msgpool, sz, UVM_KMF_WIRED); 365 return 0; 366 } 367 368 static void 369 msg_freehdr(struct __msg *msghdr) 370 { 371 372 KASSERT(mutex_owned(&msgmutex)); 373 374 while (msghdr->msg_ts > 0) { 375 short next; 376 KASSERT(msghdr->msg_spot >= 0); 377 KASSERT(msghdr->msg_spot < msginfo.msgseg); 378 379 next = msgmaps[msghdr->msg_spot].next; 380 msgmaps[msghdr->msg_spot].next = free_msgmaps; 381 free_msgmaps = msghdr->msg_spot; 382 nfree_msgmaps++; 383 msghdr->msg_spot = next; 384 if (msghdr->msg_ts >= msginfo.msgssz) 385 msghdr->msg_ts -= msginfo.msgssz; 386 else 387 msghdr->msg_ts = 0; 388 } 389 KASSERT(msghdr->msg_spot == -1); 390 msghdr->msg_next = free_msghdrs; 391 free_msghdrs = msghdr; 392 } 393 394 int 395 sys___msgctl13(struct lwp *l, const struct sys___msgctl13_args *uap, register_t *retval) 396 { 397 /* { 398 syscallarg(int) msqid; 399 syscallarg(int) cmd; 400 syscallarg(struct msqid_ds *) buf; 401 } */ 402 struct msqid_ds msqbuf; 403 int cmd, error; 404 405 cmd = SCARG(uap, cmd); 406 407 if (cmd == IPC_SET) { 408 error = copyin(SCARG(uap, buf), &msqbuf, sizeof(msqbuf)); 409 if (error) 410 return (error); 411 } 412 413 error = msgctl1(l, SCARG(uap, msqid), cmd, 414 (cmd == IPC_SET || cmd == IPC_STAT) ? &msqbuf : NULL); 415 416 if (error == 0 && cmd == IPC_STAT) 417 error = copyout(&msqbuf, SCARG(uap, buf), sizeof(msqbuf)); 418 419 return (error); 420 } 421 422 int 423 msgctl1(struct lwp *l, int msqid, int cmd, struct msqid_ds *msqbuf) 424 { 425 kauth_cred_t cred = l->l_cred; 426 struct msqid_ds *msqptr; 427 kmsq_t *msq; 428 int error = 0, ix; 429 430 MSG_PRINTF(("call to msgctl1(%d, %d)\n", msqid, cmd)); 431 432 ix = IPCID_TO_IX(msqid); 433 434 mutex_enter(&msgmutex); 435 436 if (ix < 0 || ix >= msginfo.msgmni) { 437 MSG_PRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", ix, 438 msginfo.msgmni)); 439 error = EINVAL; 440 goto unlock; 441 } 442 443 msq = &msqs[ix]; 444 msqptr = &msq->msq_u; 445 446 if (msqptr->msg_qbytes == 0) { 447 MSG_PRINTF(("no such msqid\n")); 448 error = EINVAL; 449 goto unlock; 450 } 451 if (msqptr->msg_perm._seq != IPCID_TO_SEQ(msqid)) { 452 MSG_PRINTF(("wrong sequence number\n")); 453 error = EINVAL; 454 goto unlock; 455 } 456 457 switch (cmd) { 458 case IPC_RMID: 459 { 460 struct __msg *msghdr; 461 if ((error = ipcperm(cred, &msqptr->msg_perm, IPC_M)) != 0) 462 break; 463 /* Free the message headers */ 464 msghdr = msqptr->_msg_first; 465 while (msghdr != NULL) { 466 struct __msg *msghdr_tmp; 467 468 /* Free the segments of each message */ 469 msqptr->_msg_cbytes -= msghdr->msg_ts; 470 msqptr->msg_qnum--; 471 msghdr_tmp = msghdr; 472 msghdr = msghdr->msg_next; 473 msg_freehdr(msghdr_tmp); 474 } 475 KASSERT(msqptr->_msg_cbytes == 0); 476 KASSERT(msqptr->msg_qnum == 0); 477 478 /* Mark it as free */ 479 msqptr->msg_qbytes = 0; 480 cv_broadcast(&msq->msq_cv); 481 } 482 break; 483 484 case IPC_SET: 485 if ((error = ipcperm(cred, &msqptr->msg_perm, IPC_M))) 486 break; 487 if (msqbuf->msg_qbytes > msqptr->msg_qbytes && 488 kauth_authorize_generic(cred, KAUTH_GENERIC_ISSUSER, 489 NULL) != 0) { 490 error = EPERM; 491 break; 492 } 493 if (msqbuf->msg_qbytes > msginfo.msgmnb) { 494 MSG_PRINTF(("can't increase msg_qbytes beyond %d " 495 "(truncating)\n", msginfo.msgmnb)); 496 /* silently restrict qbytes to system limit */ 497 msqbuf->msg_qbytes = msginfo.msgmnb; 498 } 499 if (msqbuf->msg_qbytes == 0) { 500 MSG_PRINTF(("can't reduce msg_qbytes to 0\n")); 501 error = EINVAL; /* XXX non-standard errno! */ 502 break; 503 } 504 msqptr->msg_perm.uid = msqbuf->msg_perm.uid; 505 msqptr->msg_perm.gid = msqbuf->msg_perm.gid; 506 msqptr->msg_perm.mode = (msqptr->msg_perm.mode & ~0777) | 507 (msqbuf->msg_perm.mode & 0777); 508 msqptr->msg_qbytes = msqbuf->msg_qbytes; 509 msqptr->msg_ctime = time_second; 510 break; 511 512 case IPC_STAT: 513 if ((error = ipcperm(cred, &msqptr->msg_perm, IPC_R))) { 514 MSG_PRINTF(("requester doesn't have read access\n")); 515 break; 516 } 517 memcpy(msqbuf, msqptr, sizeof(struct msqid_ds)); 518 break; 519 520 default: 521 MSG_PRINTF(("invalid command %d\n", cmd)); 522 error = EINVAL; 523 break; 524 } 525 526 unlock: 527 mutex_exit(&msgmutex); 528 return (error); 529 } 530 531 int 532 sys_msgget(struct lwp *l, const struct sys_msgget_args *uap, register_t *retval) 533 { 534 /* { 535 syscallarg(key_t) key; 536 syscallarg(int) msgflg; 537 } */ 538 int msqid, error = 0; 539 int key = SCARG(uap, key); 540 int msgflg = SCARG(uap, msgflg); 541 kauth_cred_t cred = l->l_cred; 542 struct msqid_ds *msqptr = NULL; 543 kmsq_t *msq; 544 545 mutex_enter(&msgmutex); 546 547 MSG_PRINTF(("msgget(0x%x, 0%o)\n", key, msgflg)); 548 549 if (key != IPC_PRIVATE) { 550 for (msqid = 0; msqid < msginfo.msgmni; msqid++) { 551 msq = &msqs[msqid]; 552 msqptr = &msq->msq_u; 553 if (msqptr->msg_qbytes != 0 && 554 msqptr->msg_perm._key == key) 555 break; 556 } 557 if (msqid < msginfo.msgmni) { 558 MSG_PRINTF(("found public key\n")); 559 if ((msgflg & IPC_CREAT) && (msgflg & IPC_EXCL)) { 560 MSG_PRINTF(("not exclusive\n")); 561 error = EEXIST; 562 goto unlock; 563 } 564 if ((error = ipcperm(cred, &msqptr->msg_perm, 565 msgflg & 0700 ))) { 566 MSG_PRINTF(("requester doesn't have 0%o access\n", 567 msgflg & 0700)); 568 goto unlock; 569 } 570 goto found; 571 } 572 } 573 574 MSG_PRINTF(("need to allocate the msqid_ds\n")); 575 if (key == IPC_PRIVATE || (msgflg & IPC_CREAT)) { 576 for (msqid = 0; msqid < msginfo.msgmni; msqid++) { 577 /* 578 * Look for an unallocated and unlocked msqid_ds. 579 * msqid_ds's can be locked by msgsnd or msgrcv while 580 * they are copying the message in/out. We can't 581 * re-use the entry until they release it. 582 */ 583 msq = &msqs[msqid]; 584 msqptr = &msq->msq_u; 585 if (msqptr->msg_qbytes == 0 && 586 (msqptr->msg_perm.mode & MSG_LOCKED) == 0) 587 break; 588 } 589 if (msqid == msginfo.msgmni) { 590 MSG_PRINTF(("no more msqid_ds's available\n")); 591 error = ENOSPC; 592 goto unlock; 593 } 594 MSG_PRINTF(("msqid %d is available\n", msqid)); 595 msqptr->msg_perm._key = key; 596 msqptr->msg_perm.cuid = kauth_cred_geteuid(cred); 597 msqptr->msg_perm.uid = kauth_cred_geteuid(cred); 598 msqptr->msg_perm.cgid = kauth_cred_getegid(cred); 599 msqptr->msg_perm.gid = kauth_cred_getegid(cred); 600 msqptr->msg_perm.mode = (msgflg & 0777); 601 /* Make sure that the returned msqid is unique */ 602 msqptr->msg_perm._seq++; 603 msqptr->_msg_first = NULL; 604 msqptr->_msg_last = NULL; 605 msqptr->_msg_cbytes = 0; 606 msqptr->msg_qnum = 0; 607 msqptr->msg_qbytes = msginfo.msgmnb; 608 msqptr->msg_lspid = 0; 609 msqptr->msg_lrpid = 0; 610 msqptr->msg_stime = 0; 611 msqptr->msg_rtime = 0; 612 msqptr->msg_ctime = time_second; 613 } else { 614 MSG_PRINTF(("didn't find it and wasn't asked to create it\n")); 615 error = ENOENT; 616 goto unlock; 617 } 618 619 found: 620 /* Construct the unique msqid */ 621 *retval = IXSEQ_TO_IPCID(msqid, msqptr->msg_perm); 622 623 unlock: 624 mutex_exit(&msgmutex); 625 return (error); 626 } 627 628 int 629 sys_msgsnd(struct lwp *l, const struct sys_msgsnd_args *uap, register_t *retval) 630 { 631 /* { 632 syscallarg(int) msqid; 633 syscallarg(const void *) msgp; 634 syscallarg(size_t) msgsz; 635 syscallarg(int) msgflg; 636 } */ 637 638 return msgsnd1(l, SCARG(uap, msqid), SCARG(uap, msgp), 639 SCARG(uap, msgsz), SCARG(uap, msgflg), sizeof(long), copyin); 640 } 641 642 int 643 msgsnd1(struct lwp *l, int msqidr, const char *user_msgp, size_t msgsz, 644 int msgflg, size_t typesz, copyin_t fetch_type) 645 { 646 int segs_needed, error = 0, msqid; 647 kauth_cred_t cred = l->l_cred; 648 struct msqid_ds *msqptr; 649 struct __msg *msghdr; 650 kmsq_t *msq; 651 short next; 652 653 MSG_PRINTF(("call to msgsnd(%d, %p, %lld, %d)\n", msqid, user_msgp, 654 (long long)msgsz, msgflg)); 655 restart: 656 msqid = IPCID_TO_IX(msqidr); 657 658 mutex_enter(&msgmutex); 659 /* In case of reallocation, we will wait for completion */ 660 while (__predict_false(msg_realloc_state)) 661 cv_wait(&msg_realloc_cv, &msgmutex); 662 663 if (msqid < 0 || msqid >= msginfo.msgmni) { 664 MSG_PRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqid, 665 msginfo.msgmni)); 666 error = EINVAL; 667 goto unlock; 668 } 669 670 msq = &msqs[msqid]; 671 msqptr = &msq->msq_u; 672 673 if (msqptr->msg_qbytes == 0) { 674 MSG_PRINTF(("no such message queue id\n")); 675 error = EINVAL; 676 goto unlock; 677 } 678 if (msqptr->msg_perm._seq != IPCID_TO_SEQ(msqidr)) { 679 MSG_PRINTF(("wrong sequence number\n")); 680 error = EINVAL; 681 goto unlock; 682 } 683 684 if ((error = ipcperm(cred, &msqptr->msg_perm, IPC_W))) { 685 MSG_PRINTF(("requester doesn't have write access\n")); 686 goto unlock; 687 } 688 689 segs_needed = (msgsz + msginfo.msgssz - 1) / msginfo.msgssz; 690 MSG_PRINTF(("msgsz=%lld, msgssz=%d, segs_needed=%d\n", 691 (long long)msgsz, msginfo.msgssz, segs_needed)); 692 for (;;) { 693 int need_more_resources = 0; 694 695 /* 696 * check msgsz [cannot be negative since it is unsigned] 697 * (inside this loop in case msg_qbytes changes while we sleep) 698 */ 699 700 if (msgsz > msqptr->msg_qbytes) { 701 MSG_PRINTF(("msgsz > msqptr->msg_qbytes\n")); 702 error = EINVAL; 703 goto unlock; 704 } 705 706 if (msqptr->msg_perm.mode & MSG_LOCKED) { 707 MSG_PRINTF(("msqid is locked\n")); 708 need_more_resources = 1; 709 } 710 if (msgsz + msqptr->_msg_cbytes > msqptr->msg_qbytes) { 711 MSG_PRINTF(("msgsz + msg_cbytes > msg_qbytes\n")); 712 need_more_resources = 1; 713 } 714 if (segs_needed > nfree_msgmaps) { 715 MSG_PRINTF(("segs_needed > nfree_msgmaps\n")); 716 need_more_resources = 1; 717 } 718 if (free_msghdrs == NULL) { 719 MSG_PRINTF(("no more msghdrs\n")); 720 need_more_resources = 1; 721 } 722 723 if (need_more_resources) { 724 int we_own_it; 725 726 if ((msgflg & IPC_NOWAIT) != 0) { 727 MSG_PRINTF(("need more resources but caller " 728 "doesn't want to wait\n")); 729 error = EAGAIN; 730 goto unlock; 731 } 732 733 if ((msqptr->msg_perm.mode & MSG_LOCKED) != 0) { 734 MSG_PRINTF(("we don't own the msqid_ds\n")); 735 we_own_it = 0; 736 } else { 737 /* Force later arrivals to wait for our 738 request */ 739 MSG_PRINTF(("we own the msqid_ds\n")); 740 msqptr->msg_perm.mode |= MSG_LOCKED; 741 we_own_it = 1; 742 } 743 744 msg_waiters++; 745 MSG_PRINTF(("goodnight\n")); 746 error = cv_wait_sig(&msq->msq_cv, &msgmutex); 747 MSG_PRINTF(("good morning, error=%d\n", error)); 748 msg_waiters--; 749 750 if (we_own_it) 751 msqptr->msg_perm.mode &= ~MSG_LOCKED; 752 753 /* 754 * In case of such state, notify reallocator and 755 * restart the call. 756 */ 757 if (msg_realloc_state) { 758 cv_broadcast(&msg_realloc_cv); 759 mutex_exit(&msgmutex); 760 goto restart; 761 } 762 763 if (error != 0) { 764 MSG_PRINTF(("msgsnd: interrupted system " 765 "call\n")); 766 error = EINTR; 767 goto unlock; 768 } 769 770 /* 771 * Make sure that the msq queue still exists 772 */ 773 774 if (msqptr->msg_qbytes == 0) { 775 MSG_PRINTF(("msqid deleted\n")); 776 error = EIDRM; 777 goto unlock; 778 } 779 } else { 780 MSG_PRINTF(("got all the resources that we need\n")); 781 break; 782 } 783 } 784 785 /* 786 * We have the resources that we need. 787 * Make sure! 788 */ 789 790 KASSERT((msqptr->msg_perm.mode & MSG_LOCKED) == 0); 791 KASSERT(segs_needed <= nfree_msgmaps); 792 KASSERT(msgsz + msqptr->_msg_cbytes <= msqptr->msg_qbytes); 793 KASSERT(free_msghdrs != NULL); 794 795 /* 796 * Re-lock the msqid_ds in case we page-fault when copying in the 797 * message 798 */ 799 800 KASSERT((msqptr->msg_perm.mode & MSG_LOCKED) == 0); 801 msqptr->msg_perm.mode |= MSG_LOCKED; 802 803 /* 804 * Allocate a message header 805 */ 806 807 msghdr = free_msghdrs; 808 free_msghdrs = msghdr->msg_next; 809 msghdr->msg_spot = -1; 810 msghdr->msg_ts = msgsz; 811 812 /* 813 * Allocate space for the message 814 */ 815 816 while (segs_needed > 0) { 817 KASSERT(nfree_msgmaps > 0); 818 KASSERT(free_msgmaps != -1); 819 KASSERT(free_msgmaps < msginfo.msgseg); 820 821 next = free_msgmaps; 822 MSG_PRINTF(("allocating segment %d to message\n", next)); 823 free_msgmaps = msgmaps[next].next; 824 nfree_msgmaps--; 825 msgmaps[next].next = msghdr->msg_spot; 826 msghdr->msg_spot = next; 827 segs_needed--; 828 } 829 830 /* 831 * Copy in the message type 832 */ 833 mutex_exit(&msgmutex); 834 error = (*fetch_type)(user_msgp, &msghdr->msg_type, typesz); 835 mutex_enter(&msgmutex); 836 if (error != 0) { 837 MSG_PRINTF(("error %d copying the message type\n", error)); 838 msg_freehdr(msghdr); 839 msqptr->msg_perm.mode &= ~MSG_LOCKED; 840 cv_broadcast(&msq->msq_cv); 841 goto unlock; 842 } 843 user_msgp += typesz; 844 845 /* 846 * Validate the message type 847 */ 848 849 if (msghdr->msg_type < 1) { 850 msg_freehdr(msghdr); 851 msqptr->msg_perm.mode &= ~MSG_LOCKED; 852 cv_broadcast(&msq->msq_cv); 853 MSG_PRINTF(("mtype (%ld) < 1\n", msghdr->msg_type)); 854 goto unlock; 855 } 856 857 /* 858 * Copy in the message body 859 */ 860 861 next = msghdr->msg_spot; 862 while (msgsz > 0) { 863 size_t tlen; 864 KASSERT(next > -1); 865 KASSERT(next < msginfo.msgseg); 866 867 if (msgsz > msginfo.msgssz) 868 tlen = msginfo.msgssz; 869 else 870 tlen = msgsz; 871 mutex_exit(&msgmutex); 872 error = copyin(user_msgp, &msgpool[next * msginfo.msgssz], tlen); 873 mutex_enter(&msgmutex); 874 if (error != 0) { 875 MSG_PRINTF(("error %d copying in message segment\n", 876 error)); 877 msg_freehdr(msghdr); 878 msqptr->msg_perm.mode &= ~MSG_LOCKED; 879 cv_broadcast(&msq->msq_cv); 880 goto unlock; 881 } 882 msgsz -= tlen; 883 user_msgp += tlen; 884 next = msgmaps[next].next; 885 } 886 KASSERT(next == -1); 887 888 /* 889 * We've got the message. Unlock the msqid_ds. 890 */ 891 892 msqptr->msg_perm.mode &= ~MSG_LOCKED; 893 894 /* 895 * Make sure that the msqid_ds is still allocated. 896 */ 897 898 if (msqptr->msg_qbytes == 0) { 899 msg_freehdr(msghdr); 900 cv_broadcast(&msq->msq_cv); 901 error = EIDRM; 902 goto unlock; 903 } 904 905 /* 906 * Put the message into the queue 907 */ 908 909 if (msqptr->_msg_first == NULL) { 910 msqptr->_msg_first = msghdr; 911 msqptr->_msg_last = msghdr; 912 } else { 913 msqptr->_msg_last->msg_next = msghdr; 914 msqptr->_msg_last = msghdr; 915 } 916 msqptr->_msg_last->msg_next = NULL; 917 918 msqptr->_msg_cbytes += msghdr->msg_ts; 919 msqptr->msg_qnum++; 920 msqptr->msg_lspid = l->l_proc->p_pid; 921 msqptr->msg_stime = time_second; 922 923 cv_broadcast(&msq->msq_cv); 924 925 unlock: 926 mutex_exit(&msgmutex); 927 return error; 928 } 929 930 int 931 sys_msgrcv(struct lwp *l, const struct sys_msgrcv_args *uap, register_t *retval) 932 { 933 /* { 934 syscallarg(int) msqid; 935 syscallarg(void *) msgp; 936 syscallarg(size_t) msgsz; 937 syscallarg(long) msgtyp; 938 syscallarg(int) msgflg; 939 } */ 940 941 return msgrcv1(l, SCARG(uap, msqid), SCARG(uap, msgp), 942 SCARG(uap, msgsz), SCARG(uap, msgtyp), SCARG(uap, msgflg), 943 sizeof(long), copyout, retval); 944 } 945 946 int 947 msgrcv1(struct lwp *l, int msqidr, char *user_msgp, size_t msgsz, long msgtyp, 948 int msgflg, size_t typesz, copyout_t put_type, register_t *retval) 949 { 950 size_t len; 951 kauth_cred_t cred = l->l_cred; 952 struct msqid_ds *msqptr; 953 struct __msg *msghdr; 954 int error = 0, msqid; 955 kmsq_t *msq; 956 short next; 957 958 MSG_PRINTF(("call to msgrcv(%d, %p, %lld, %ld, %d)\n", msqid, 959 user_msgp, (long long)msgsz, msgtyp, msgflg)); 960 restart: 961 msqid = IPCID_TO_IX(msqidr); 962 963 mutex_enter(&msgmutex); 964 /* In case of reallocation, we will wait for completion */ 965 while (__predict_false(msg_realloc_state)) 966 cv_wait(&msg_realloc_cv, &msgmutex); 967 968 if (msqid < 0 || msqid >= msginfo.msgmni) { 969 MSG_PRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqid, 970 msginfo.msgmni)); 971 error = EINVAL; 972 goto unlock; 973 } 974 975 msq = &msqs[msqid]; 976 msqptr = &msq->msq_u; 977 978 if (msqptr->msg_qbytes == 0) { 979 MSG_PRINTF(("no such message queue id\n")); 980 error = EINVAL; 981 goto unlock; 982 } 983 if (msqptr->msg_perm._seq != IPCID_TO_SEQ(msqidr)) { 984 MSG_PRINTF(("wrong sequence number\n")); 985 error = EINVAL; 986 goto unlock; 987 } 988 989 if ((error = ipcperm(cred, &msqptr->msg_perm, IPC_R))) { 990 MSG_PRINTF(("requester doesn't have read access\n")); 991 goto unlock; 992 } 993 994 msghdr = NULL; 995 while (msghdr == NULL) { 996 if (msgtyp == 0) { 997 msghdr = msqptr->_msg_first; 998 if (msghdr != NULL) { 999 if (msgsz < msghdr->msg_ts && 1000 (msgflg & MSG_NOERROR) == 0) { 1001 MSG_PRINTF(("first msg on the queue " 1002 "is too big (want %lld, got %d)\n", 1003 (long long)msgsz, msghdr->msg_ts)); 1004 error = E2BIG; 1005 goto unlock; 1006 } 1007 if (msqptr->_msg_first == msqptr->_msg_last) { 1008 msqptr->_msg_first = NULL; 1009 msqptr->_msg_last = NULL; 1010 } else { 1011 msqptr->_msg_first = msghdr->msg_next; 1012 KASSERT(msqptr->_msg_first != NULL); 1013 } 1014 } 1015 } else { 1016 struct __msg *previous; 1017 struct __msg **prev; 1018 1019 for (previous = NULL, prev = &msqptr->_msg_first; 1020 (msghdr = *prev) != NULL; 1021 previous = msghdr, prev = &msghdr->msg_next) { 1022 /* 1023 * Is this message's type an exact match or is 1024 * this message's type less than or equal to 1025 * the absolute value of a negative msgtyp? 1026 * Note that the second half of this test can 1027 * NEVER be true if msgtyp is positive since 1028 * msg_type is always positive! 1029 */ 1030 1031 if (msgtyp != msghdr->msg_type && 1032 msghdr->msg_type > -msgtyp) 1033 continue; 1034 1035 MSG_PRINTF(("found message type %ld, requested %ld\n", 1036 msghdr->msg_type, msgtyp)); 1037 if (msgsz < msghdr->msg_ts && 1038 (msgflg & MSG_NOERROR) == 0) { 1039 MSG_PRINTF(("requested message on the queue " 1040 "is too big (want %lld, got %d)\n", 1041 (long long)msgsz, msghdr->msg_ts)); 1042 error = E2BIG; 1043 goto unlock; 1044 } 1045 *prev = msghdr->msg_next; 1046 if (msghdr != msqptr->_msg_last) 1047 break; 1048 if (previous == NULL) { 1049 KASSERT(prev == &msqptr->_msg_first); 1050 msqptr->_msg_first = NULL; 1051 msqptr->_msg_last = NULL; 1052 } else { 1053 KASSERT(prev != &msqptr->_msg_first); 1054 msqptr->_msg_last = previous; 1055 } 1056 break; 1057 } 1058 } 1059 1060 /* 1061 * We've either extracted the msghdr for the appropriate 1062 * message or there isn't one. 1063 * If there is one then bail out of this loop. 1064 */ 1065 if (msghdr != NULL) 1066 break; 1067 1068 /* 1069 * Hmph! No message found. Does the user want to wait? 1070 */ 1071 1072 if ((msgflg & IPC_NOWAIT) != 0) { 1073 MSG_PRINTF(("no appropriate message found (msgtyp=%ld)\n", 1074 msgtyp)); 1075 error = ENOMSG; 1076 goto unlock; 1077 } 1078 1079 /* 1080 * Wait for something to happen 1081 */ 1082 1083 msg_waiters++; 1084 MSG_PRINTF(("msgrcv: goodnight\n")); 1085 error = cv_wait_sig(&msq->msq_cv, &msgmutex); 1086 MSG_PRINTF(("msgrcv: good morning (error=%d)\n", error)); 1087 msg_waiters--; 1088 1089 /* 1090 * In case of such state, notify reallocator and 1091 * restart the call. 1092 */ 1093 if (msg_realloc_state) { 1094 cv_broadcast(&msg_realloc_cv); 1095 mutex_exit(&msgmutex); 1096 goto restart; 1097 } 1098 1099 if (error != 0) { 1100 MSG_PRINTF(("msgsnd: interrupted system call\n")); 1101 error = EINTR; 1102 goto unlock; 1103 } 1104 1105 /* 1106 * Make sure that the msq queue still exists 1107 */ 1108 1109 if (msqptr->msg_qbytes == 0 || 1110 msqptr->msg_perm._seq != IPCID_TO_SEQ(msqidr)) { 1111 MSG_PRINTF(("msqid deleted\n")); 1112 error = EIDRM; 1113 goto unlock; 1114 } 1115 } 1116 1117 /* 1118 * Return the message to the user. 1119 * 1120 * First, do the bookkeeping (before we risk being interrupted). 1121 */ 1122 1123 msqptr->_msg_cbytes -= msghdr->msg_ts; 1124 msqptr->msg_qnum--; 1125 msqptr->msg_lrpid = l->l_proc->p_pid; 1126 msqptr->msg_rtime = time_second; 1127 1128 /* 1129 * Make msgsz the actual amount that we'll be returning. 1130 * Note that this effectively truncates the message if it is too long 1131 * (since msgsz is never increased). 1132 */ 1133 1134 MSG_PRINTF(("found a message, msgsz=%lld, msg_ts=%d\n", 1135 (long long)msgsz, msghdr->msg_ts)); 1136 if (msgsz > msghdr->msg_ts) 1137 msgsz = msghdr->msg_ts; 1138 1139 /* 1140 * Return the type to the user. 1141 */ 1142 mutex_exit(&msgmutex); 1143 error = (*put_type)(&msghdr->msg_type, user_msgp, typesz); 1144 mutex_enter(&msgmutex); 1145 if (error != 0) { 1146 MSG_PRINTF(("error (%d) copying out message type\n", error)); 1147 msg_freehdr(msghdr); 1148 cv_broadcast(&msq->msq_cv); 1149 goto unlock; 1150 } 1151 user_msgp += typesz; 1152 1153 /* 1154 * Return the segments to the user 1155 */ 1156 1157 next = msghdr->msg_spot; 1158 for (len = 0; len < msgsz; len += msginfo.msgssz) { 1159 size_t tlen; 1160 KASSERT(next > -1); 1161 KASSERT(next < msginfo.msgseg); 1162 1163 if (msgsz - len > msginfo.msgssz) 1164 tlen = msginfo.msgssz; 1165 else 1166 tlen = msgsz - len; 1167 mutex_exit(&msgmutex); 1168 error = (*put_type)(&msgpool[next * msginfo.msgssz], 1169 user_msgp, tlen); 1170 mutex_enter(&msgmutex); 1171 if (error != 0) { 1172 MSG_PRINTF(("error (%d) copying out message segment\n", 1173 error)); 1174 msg_freehdr(msghdr); 1175 cv_broadcast(&msq->msq_cv); 1176 goto unlock; 1177 } 1178 user_msgp += tlen; 1179 next = msgmaps[next].next; 1180 } 1181 1182 /* 1183 * Done, return the actual number of bytes copied out. 1184 */ 1185 1186 msg_freehdr(msghdr); 1187 cv_broadcast(&msq->msq_cv); 1188 *retval = msgsz; 1189 1190 unlock: 1191 mutex_exit(&msgmutex); 1192 return error; 1193 } 1194 1195 /* 1196 * Sysctl initialization and nodes. 1197 */ 1198 1199 static int 1200 sysctl_ipc_msgmni(SYSCTLFN_ARGS) 1201 { 1202 int newsize, error; 1203 struct sysctlnode node; 1204 node = *rnode; 1205 node.sysctl_data = &newsize; 1206 1207 newsize = msginfo.msgmni; 1208 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1209 if (error || newp == NULL) 1210 return error; 1211 1212 sysctl_unlock(); 1213 error = msgrealloc(newsize, msginfo.msgseg); 1214 sysctl_relock(); 1215 return error; 1216 } 1217 1218 static int 1219 sysctl_ipc_msgseg(SYSCTLFN_ARGS) 1220 { 1221 int newsize, error; 1222 struct sysctlnode node; 1223 node = *rnode; 1224 node.sysctl_data = &newsize; 1225 1226 newsize = msginfo.msgseg; 1227 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1228 if (error || newp == NULL) 1229 return error; 1230 1231 sysctl_unlock(); 1232 error = msgrealloc(msginfo.msgmni, newsize); 1233 sysctl_relock(); 1234 return error; 1235 } 1236 1237 SYSCTL_SETUP(sysctl_ipc_msg_setup, "sysctl kern.ipc subtree setup") 1238 { 1239 const struct sysctlnode *node = NULL; 1240 1241 sysctl_createv(clog, 0, NULL, NULL, 1242 CTLFLAG_PERMANENT, 1243 CTLTYPE_NODE, "kern", NULL, 1244 NULL, 0, NULL, 0, 1245 CTL_KERN, CTL_EOL); 1246 sysctl_createv(clog, 0, NULL, &node, 1247 CTLFLAG_PERMANENT, 1248 CTLTYPE_NODE, "ipc", 1249 SYSCTL_DESCR("SysV IPC options"), 1250 NULL, 0, NULL, 0, 1251 CTL_KERN, KERN_SYSVIPC, CTL_EOL); 1252 1253 if (node == NULL) 1254 return; 1255 1256 sysctl_createv(clog, 0, &node, NULL, 1257 CTLFLAG_PERMANENT | CTLFLAG_READWRITE, 1258 CTLTYPE_INT, "msgmni", 1259 SYSCTL_DESCR("Max number of message queue identifiers"), 1260 sysctl_ipc_msgmni, 0, &msginfo.msgmni, 0, 1261 CTL_CREATE, CTL_EOL); 1262 sysctl_createv(clog, 0, &node, NULL, 1263 CTLFLAG_PERMANENT | CTLFLAG_READWRITE, 1264 CTLTYPE_INT, "msgseg", 1265 SYSCTL_DESCR("Max number of number of message segments"), 1266 sysctl_ipc_msgseg, 0, &msginfo.msgseg, 0, 1267 CTL_CREATE, CTL_EOL); 1268 } 1269