1 /*- 2 * Implementation of SVID messages 3 * 4 * Author: Daniel Boulet 5 * 6 * Copyright 1993 Daniel Boulet and RTMX Inc. 7 * 8 * This system call was implemented by Daniel Boulet under contract from RTMX. 9 * 10 * Redistribution and use in source forms, with and without modification, 11 * are permitted provided that this entire comment appears intact. 12 * 13 * Redistribution in binary form may occur without any restrictions. 14 * Obviously, it would be nice if you gave credit where credit is due 15 * but requiring it would be too onerous. 16 * 17 * This software is provided ``AS IS'' without any warranties of any kind. 18 */ 19 /*- 20 * Copyright (c) 2003-2005 McAfee, Inc. 21 * All rights reserved. 22 * 23 * This software was developed for the FreeBSD Project in part by McAfee 24 * Research, the Security Research Division of McAfee, Inc under DARPA/SPAWAR 25 * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS research 26 * program. 27 * 28 * Redistribution and use in source and binary forms, with or without 29 * modification, are permitted provided that the following conditions 30 * are met: 31 * 1. Redistributions of source code must retain the above copyright 32 * notice, this list of conditions and the following disclaimer. 33 * 2. Redistributions in binary form must reproduce the above copyright 34 * notice, this list of conditions and the following disclaimer in the 35 * documentation and/or other materials provided with the distribution. 36 * 37 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 38 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 39 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 40 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 41 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 42 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 43 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 44 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 45 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 46 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 47 * SUCH DAMAGE. 48 */ 49 50 #include <sys/cdefs.h> 51 __FBSDID("$FreeBSD$"); 52 53 #include "opt_sysvipc.h" 54 #include "opt_mac.h" 55 56 #include <sys/param.h> 57 #include <sys/systm.h> 58 #include <sys/sysproto.h> 59 #include <sys/kernel.h> 60 #include <sys/proc.h> 61 #include <sys/lock.h> 62 #include <sys/mac.h> 63 #include <sys/mutex.h> 64 #include <sys/module.h> 65 #include <sys/msg.h> 66 #include <sys/syscall.h> 67 #include <sys/syscallsubr.h> 68 #include <sys/sysent.h> 69 #include <sys/sysctl.h> 70 #include <sys/malloc.h> 71 #include <sys/jail.h> 72 73 static MALLOC_DEFINE(M_MSG, "msg", "SVID compatible message queues"); 74 75 static void msginit(void); 76 static int msgunload(void); 77 static int sysvmsg_modload(struct module *, int, void *); 78 79 #ifdef MSG_DEBUG 80 #define DPRINTF(a) printf a 81 #else 82 #define DPRINTF(a) 83 #endif 84 85 static void msg_freehdr(struct msg *msghdr); 86 87 /* XXX casting to (sy_call_t *) is bogus, as usual. */ 88 static sy_call_t *msgcalls[] = { 89 (sy_call_t *)msgctl, (sy_call_t *)msgget, 90 (sy_call_t *)msgsnd, (sy_call_t *)msgrcv 91 }; 92 93 #ifndef MSGSSZ 94 #define MSGSSZ 8 /* Each segment must be 2^N long */ 95 #endif 96 #ifndef MSGSEG 97 #define MSGSEG 2048 /* must be less than 32767 */ 98 #endif 99 #define MSGMAX (MSGSSZ*MSGSEG) 100 #ifndef MSGMNB 101 #define MSGMNB 2048 /* max # of bytes in a queue */ 102 #endif 103 #ifndef MSGMNI 104 #define MSGMNI 40 105 #endif 106 #ifndef MSGTQL 107 #define MSGTQL 40 108 #endif 109 110 /* 111 * Based on the configuration parameters described in an SVR2 (yes, two) 112 * config(1m) man page. 113 * 114 * Each message is broken up and stored in segments that are msgssz bytes 115 * long. For efficiency reasons, this should be a power of two. Also, 116 * it doesn't make sense if it is less than 8 or greater than about 256. 117 * Consequently, msginit in kern/sysv_msg.c checks that msgssz is a power of 118 * two between 8 and 1024 inclusive (and panic's if it isn't). 119 */ 120 struct msginfo msginfo = { 121 MSGMAX, /* max chars in a message */ 122 MSGMNI, /* # of message queue identifiers */ 123 MSGMNB, /* max chars in a queue */ 124 MSGTQL, /* max messages in system */ 125 MSGSSZ, /* size of a message segment */ 126 /* (must be small power of 2 greater than 4) */ 127 MSGSEG /* number of message segments */ 128 }; 129 130 /* 131 * macros to convert between msqid_ds's and msqid's. 132 * (specific to this implementation) 133 */ 134 #define MSQID(ix,ds) ((ix) & 0xffff | (((ds).msg_perm.seq << 16) & 0xffff0000)) 135 #define MSQID_IX(id) ((id) & 0xffff) 136 #define MSQID_SEQ(id) (((id) >> 16) & 0xffff) 137 138 /* 139 * The rest of this file is specific to this particular implementation. 140 */ 141 142 struct msgmap { 143 short next; /* next segment in buffer */ 144 /* -1 -> available */ 145 /* 0..(MSGSEG-1) -> index of next segment */ 146 }; 147 148 #define MSG_LOCKED 01000 /* Is this msqid_ds locked? */ 149 150 static int nfree_msgmaps; /* # of free map entries */ 151 static short free_msgmaps; /* head of linked list of free map entries */ 152 static struct msg *free_msghdrs;/* list of free msg headers */ 153 static char *msgpool; /* MSGMAX byte long msg buffer pool */ 154 static struct msgmap *msgmaps; /* MSGSEG msgmap structures */ 155 static struct msg *msghdrs; /* MSGTQL msg headers */ 156 static struct msqid_kernel *msqids; /* MSGMNI msqid_kernel struct's */ 157 static struct mtx msq_mtx; /* global mutex for message queues. */ 158 159 static void 160 msginit() 161 { 162 register int i; 163 164 TUNABLE_INT_FETCH("kern.ipc.msgseg", &msginfo.msgseg); 165 TUNABLE_INT_FETCH("kern.ipc.msgssz", &msginfo.msgssz); 166 msginfo.msgmax = msginfo.msgseg * msginfo.msgssz; 167 TUNABLE_INT_FETCH("kern.ipc.msgmni", &msginfo.msgmni); 168 TUNABLE_INT_FETCH("kern.ipc.msgmnb", &msginfo.msgmnb); 169 TUNABLE_INT_FETCH("kern.ipc.msgtql", &msginfo.msgtql); 170 171 msgpool = malloc(msginfo.msgmax, M_MSG, M_WAITOK); 172 if (msgpool == NULL) 173 panic("msgpool is NULL"); 174 msgmaps = malloc(sizeof(struct msgmap) * msginfo.msgseg, M_MSG, M_WAITOK); 175 if (msgmaps == NULL) 176 panic("msgmaps is NULL"); 177 msghdrs = malloc(sizeof(struct msg) * msginfo.msgtql, M_MSG, M_WAITOK); 178 if (msghdrs == NULL) 179 panic("msghdrs is NULL"); 180 msqids = malloc(sizeof(struct msqid_kernel) * msginfo.msgmni, M_MSG, 181 M_WAITOK); 182 if (msqids == NULL) 183 panic("msqids is NULL"); 184 185 /* 186 * msginfo.msgssz should be a power of two for efficiency reasons. 187 * It is also pretty silly if msginfo.msgssz is less than 8 188 * or greater than about 256 so ... 189 */ 190 191 i = 8; 192 while (i < 1024 && i != msginfo.msgssz) 193 i <<= 1; 194 if (i != msginfo.msgssz) { 195 DPRINTF(("msginfo.msgssz=%d (0x%x)\n", msginfo.msgssz, 196 msginfo.msgssz)); 197 panic("msginfo.msgssz not a small power of 2"); 198 } 199 200 if (msginfo.msgseg > 32767) { 201 DPRINTF(("msginfo.msgseg=%d\n", msginfo.msgseg)); 202 panic("msginfo.msgseg > 32767"); 203 } 204 205 if (msgmaps == NULL) 206 panic("msgmaps is NULL"); 207 208 for (i = 0; i < msginfo.msgseg; i++) { 209 if (i > 0) 210 msgmaps[i-1].next = i; 211 msgmaps[i].next = -1; /* implies entry is available */ 212 } 213 free_msgmaps = 0; 214 nfree_msgmaps = msginfo.msgseg; 215 216 if (msghdrs == NULL) 217 panic("msghdrs is NULL"); 218 219 for (i = 0; i < msginfo.msgtql; i++) { 220 msghdrs[i].msg_type = 0; 221 if (i > 0) 222 msghdrs[i-1].msg_next = &msghdrs[i]; 223 msghdrs[i].msg_next = NULL; 224 #ifdef MAC 225 mac_init_sysv_msgmsg(&msghdrs[i]); 226 #endif 227 } 228 free_msghdrs = &msghdrs[0]; 229 230 if (msqids == NULL) 231 panic("msqids is NULL"); 232 233 for (i = 0; i < msginfo.msgmni; i++) { 234 msqids[i].u.msg_qbytes = 0; /* implies entry is available */ 235 msqids[i].u.msg_perm.seq = 0; /* reset to a known value */ 236 msqids[i].u.msg_perm.mode = 0; 237 #ifdef MAC 238 mac_init_sysv_msgqueue(&msqids[i]); 239 #endif 240 } 241 mtx_init(&msq_mtx, "msq", NULL, MTX_DEF); 242 } 243 244 static int 245 msgunload() 246 { 247 struct msqid_kernel *msqkptr; 248 int msqid; 249 #ifdef MAC 250 int i; 251 #endif 252 253 for (msqid = 0; msqid < msginfo.msgmni; msqid++) { 254 /* 255 * Look for an unallocated and unlocked msqid_ds. 256 * msqid_ds's can be locked by msgsnd or msgrcv while 257 * they are copying the message in/out. We can't 258 * re-use the entry until they release it. 259 */ 260 msqkptr = &msqids[msqid]; 261 if (msqkptr->u.msg_qbytes != 0 || 262 (msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0) 263 break; 264 } 265 if (msqid != msginfo.msgmni) 266 return (EBUSY); 267 268 #ifdef MAC 269 for (i = 0; i < msginfo.msgtql; i++) 270 mac_destroy_sysv_msgmsg(&msghdrs[i]); 271 for (msqid = 0; msqid < msginfo.msgmni; msqid++) 272 mac_destroy_sysv_msgqueue(&msqids[msqid]); 273 #endif 274 free(msgpool, M_MSG); 275 free(msgmaps, M_MSG); 276 free(msghdrs, M_MSG); 277 free(msqids, M_MSG); 278 mtx_destroy(&msq_mtx); 279 return (0); 280 } 281 282 283 static int 284 sysvmsg_modload(struct module *module, int cmd, void *arg) 285 { 286 int error = 0; 287 288 switch (cmd) { 289 case MOD_LOAD: 290 msginit(); 291 break; 292 case MOD_UNLOAD: 293 error = msgunload(); 294 break; 295 case MOD_SHUTDOWN: 296 break; 297 default: 298 error = EINVAL; 299 break; 300 } 301 return (error); 302 } 303 304 static moduledata_t sysvmsg_mod = { 305 "sysvmsg", 306 &sysvmsg_modload, 307 NULL 308 }; 309 310 SYSCALL_MODULE_HELPER(msgsys); 311 SYSCALL_MODULE_HELPER(msgctl); 312 SYSCALL_MODULE_HELPER(msgget); 313 SYSCALL_MODULE_HELPER(msgsnd); 314 SYSCALL_MODULE_HELPER(msgrcv); 315 316 DECLARE_MODULE(sysvmsg, sysvmsg_mod, 317 SI_SUB_SYSV_MSG, SI_ORDER_FIRST); 318 MODULE_VERSION(sysvmsg, 1); 319 320 /* 321 * Entry point for all MSG calls 322 * 323 * MPSAFE 324 */ 325 int 326 msgsys(td, uap) 327 struct thread *td; 328 /* XXX actually varargs. */ 329 struct msgsys_args /* { 330 int which; 331 int a2; 332 int a3; 333 int a4; 334 int a5; 335 int a6; 336 } */ *uap; 337 { 338 int error; 339 340 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 341 return (ENOSYS); 342 if (uap->which < 0 || 343 uap->which >= sizeof(msgcalls)/sizeof(msgcalls[0])) 344 return (EINVAL); 345 error = (*msgcalls[uap->which])(td, &uap->a2); 346 return (error); 347 } 348 349 static void 350 msg_freehdr(msghdr) 351 struct msg *msghdr; 352 { 353 while (msghdr->msg_ts > 0) { 354 short next; 355 if (msghdr->msg_spot < 0 || msghdr->msg_spot >= msginfo.msgseg) 356 panic("msghdr->msg_spot out of range"); 357 next = msgmaps[msghdr->msg_spot].next; 358 msgmaps[msghdr->msg_spot].next = free_msgmaps; 359 free_msgmaps = msghdr->msg_spot; 360 nfree_msgmaps++; 361 msghdr->msg_spot = next; 362 if (msghdr->msg_ts >= msginfo.msgssz) 363 msghdr->msg_ts -= msginfo.msgssz; 364 else 365 msghdr->msg_ts = 0; 366 } 367 if (msghdr->msg_spot != -1) 368 panic("msghdr->msg_spot != -1"); 369 msghdr->msg_next = free_msghdrs; 370 free_msghdrs = msghdr; 371 #ifdef MAC 372 mac_cleanup_sysv_msgmsg(msghdr); 373 #endif 374 } 375 376 #ifndef _SYS_SYSPROTO_H_ 377 struct msgctl_args { 378 int msqid; 379 int cmd; 380 struct msqid_ds *buf; 381 }; 382 #endif 383 384 /* 385 * MPSAFE 386 */ 387 int 388 msgctl(td, uap) 389 struct thread *td; 390 register struct msgctl_args *uap; 391 { 392 int msqid = uap->msqid; 393 int cmd = uap->cmd; 394 struct msqid_ds msqbuf; 395 int error; 396 397 DPRINTF(("call to msgctl(%d, %d, 0x%x)\n", msqid, cmd, uap->buf)); 398 if (cmd == IPC_SET && 399 (error = copyin(uap->buf, &msqbuf, sizeof(msqbuf))) != 0) 400 return (error); 401 error = kern_msgctl(td, msqid, cmd, &msqbuf); 402 if (cmd == IPC_STAT && error == 0) 403 error = copyout(&msqbuf, uap->buf, sizeof(struct msqid_ds)); 404 return (error); 405 } 406 407 int 408 kern_msgctl(td, msqid, cmd, msqbuf) 409 struct thread *td; 410 int msqid; 411 int cmd; 412 struct msqid_ds *msqbuf; 413 { 414 int rval, error, msqix; 415 register struct msqid_kernel *msqkptr; 416 417 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 418 return (ENOSYS); 419 420 msqix = IPCID_TO_IX(msqid); 421 422 if (msqix < 0 || msqix >= msginfo.msgmni) { 423 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix, 424 msginfo.msgmni)); 425 return (EINVAL); 426 } 427 428 msqkptr = &msqids[msqix]; 429 430 mtx_lock(&msq_mtx); 431 if (msqkptr->u.msg_qbytes == 0) { 432 DPRINTF(("no such msqid\n")); 433 error = EINVAL; 434 goto done2; 435 } 436 if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) { 437 DPRINTF(("wrong sequence number\n")); 438 error = EINVAL; 439 goto done2; 440 } 441 #ifdef MAC 442 error = mac_check_sysv_msqctl(td->td_ucred, msqkptr, cmd); 443 if (error != 0) 444 goto done2; 445 #endif 446 447 error = 0; 448 rval = 0; 449 450 switch (cmd) { 451 452 case IPC_RMID: 453 { 454 struct msg *msghdr; 455 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_M))) 456 goto done2; 457 458 #ifdef MAC 459 /* 460 * Check that the thread has MAC access permissions to 461 * individual msghdrs. Note: We need to do this in a 462 * separate loop because the actual loop alters the 463 * msq/msghdr info as it progresses, and there is no going 464 * back if half the way through we discover that the 465 * thread cannot free a certain msghdr. The msq will get 466 * into an inconsistent state. 467 */ 468 for (msghdr = msqkptr->u.msg_first; msghdr != NULL; 469 msghdr = msghdr->msg_next) { 470 error = mac_check_sysv_msgrmid(td->td_ucred, msghdr); 471 if (error != 0) 472 goto done2; 473 } 474 #endif 475 476 /* Free the message headers */ 477 msghdr = msqkptr->u.msg_first; 478 while (msghdr != NULL) { 479 struct msg *msghdr_tmp; 480 481 /* Free the segments of each message */ 482 msqkptr->u.msg_cbytes -= msghdr->msg_ts; 483 msqkptr->u.msg_qnum--; 484 msghdr_tmp = msghdr; 485 msghdr = msghdr->msg_next; 486 msg_freehdr(msghdr_tmp); 487 } 488 489 if (msqkptr->u.msg_cbytes != 0) 490 panic("msg_cbytes is screwed up"); 491 if (msqkptr->u.msg_qnum != 0) 492 panic("msg_qnum is screwed up"); 493 494 msqkptr->u.msg_qbytes = 0; /* Mark it as free */ 495 496 #ifdef MAC 497 mac_cleanup_sysv_msgqueue(msqkptr); 498 #endif 499 500 wakeup(msqkptr); 501 } 502 503 break; 504 505 case IPC_SET: 506 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_M))) 507 goto done2; 508 if (msqbuf->msg_qbytes > msqkptr->u.msg_qbytes) { 509 error = suser(td); 510 if (error) 511 goto done2; 512 } 513 if (msqbuf->msg_qbytes > msginfo.msgmnb) { 514 DPRINTF(("can't increase msg_qbytes beyond %d" 515 "(truncating)\n", msginfo.msgmnb)); 516 msqbuf->msg_qbytes = msginfo.msgmnb; /* silently restrict qbytes to system limit */ 517 } 518 if (msqbuf->msg_qbytes == 0) { 519 DPRINTF(("can't reduce msg_qbytes to 0\n")); 520 error = EINVAL; /* non-standard errno! */ 521 goto done2; 522 } 523 msqkptr->u.msg_perm.uid = msqbuf->msg_perm.uid; /* change the owner */ 524 msqkptr->u.msg_perm.gid = msqbuf->msg_perm.gid; /* change the owner */ 525 msqkptr->u.msg_perm.mode = (msqkptr->u.msg_perm.mode & ~0777) | 526 (msqbuf->msg_perm.mode & 0777); 527 msqkptr->u.msg_qbytes = msqbuf->msg_qbytes; 528 msqkptr->u.msg_ctime = time_second; 529 break; 530 531 case IPC_STAT: 532 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_R))) { 533 DPRINTF(("requester doesn't have read access\n")); 534 goto done2; 535 } 536 *msqbuf = msqkptr->u; 537 break; 538 539 default: 540 DPRINTF(("invalid command %d\n", cmd)); 541 error = EINVAL; 542 goto done2; 543 } 544 545 if (error == 0) 546 td->td_retval[0] = rval; 547 done2: 548 mtx_unlock(&msq_mtx); 549 return (error); 550 } 551 552 #ifndef _SYS_SYSPROTO_H_ 553 struct msgget_args { 554 key_t key; 555 int msgflg; 556 }; 557 #endif 558 559 /* 560 * MPSAFE 561 */ 562 int 563 msgget(td, uap) 564 struct thread *td; 565 register struct msgget_args *uap; 566 { 567 int msqid, error = 0; 568 int key = uap->key; 569 int msgflg = uap->msgflg; 570 struct ucred *cred = td->td_ucred; 571 register struct msqid_kernel *msqkptr = NULL; 572 573 DPRINTF(("msgget(0x%x, 0%o)\n", key, msgflg)); 574 575 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 576 return (ENOSYS); 577 578 mtx_lock(&msq_mtx); 579 if (key != IPC_PRIVATE) { 580 for (msqid = 0; msqid < msginfo.msgmni; msqid++) { 581 msqkptr = &msqids[msqid]; 582 if (msqkptr->u.msg_qbytes != 0 && 583 msqkptr->u.msg_perm.key == key) 584 break; 585 } 586 if (msqid < msginfo.msgmni) { 587 DPRINTF(("found public key\n")); 588 if ((msgflg & IPC_CREAT) && (msgflg & IPC_EXCL)) { 589 DPRINTF(("not exclusive\n")); 590 error = EEXIST; 591 goto done2; 592 } 593 if ((error = ipcperm(td, &msqkptr->u.msg_perm, 594 msgflg & 0700))) { 595 DPRINTF(("requester doesn't have 0%o access\n", 596 msgflg & 0700)); 597 goto done2; 598 } 599 #ifdef MAC 600 error = mac_check_sysv_msqget(cred, msqkptr); 601 if (error != 0) 602 goto done2; 603 #endif 604 goto found; 605 } 606 } 607 608 DPRINTF(("need to allocate the msqid_ds\n")); 609 if (key == IPC_PRIVATE || (msgflg & IPC_CREAT)) { 610 for (msqid = 0; msqid < msginfo.msgmni; msqid++) { 611 /* 612 * Look for an unallocated and unlocked msqid_ds. 613 * msqid_ds's can be locked by msgsnd or msgrcv while 614 * they are copying the message in/out. We can't 615 * re-use the entry until they release it. 616 */ 617 msqkptr = &msqids[msqid]; 618 if (msqkptr->u.msg_qbytes == 0 && 619 (msqkptr->u.msg_perm.mode & MSG_LOCKED) == 0) 620 break; 621 } 622 if (msqid == msginfo.msgmni) { 623 DPRINTF(("no more msqid_ds's available\n")); 624 error = ENOSPC; 625 goto done2; 626 } 627 DPRINTF(("msqid %d is available\n", msqid)); 628 msqkptr->u.msg_perm.key = key; 629 msqkptr->u.msg_perm.cuid = cred->cr_uid; 630 msqkptr->u.msg_perm.uid = cred->cr_uid; 631 msqkptr->u.msg_perm.cgid = cred->cr_gid; 632 msqkptr->u.msg_perm.gid = cred->cr_gid; 633 msqkptr->u.msg_perm.mode = (msgflg & 0777); 634 /* Make sure that the returned msqid is unique */ 635 msqkptr->u.msg_perm.seq = (msqkptr->u.msg_perm.seq + 1) & 0x7fff; 636 msqkptr->u.msg_first = NULL; 637 msqkptr->u.msg_last = NULL; 638 msqkptr->u.msg_cbytes = 0; 639 msqkptr->u.msg_qnum = 0; 640 msqkptr->u.msg_qbytes = msginfo.msgmnb; 641 msqkptr->u.msg_lspid = 0; 642 msqkptr->u.msg_lrpid = 0; 643 msqkptr->u.msg_stime = 0; 644 msqkptr->u.msg_rtime = 0; 645 msqkptr->u.msg_ctime = time_second; 646 #ifdef MAC 647 mac_create_sysv_msgqueue(cred, msqkptr); 648 #endif 649 } else { 650 DPRINTF(("didn't find it and wasn't asked to create it\n")); 651 error = ENOENT; 652 goto done2; 653 } 654 655 found: 656 /* Construct the unique msqid */ 657 td->td_retval[0] = IXSEQ_TO_IPCID(msqid, msqkptr->u.msg_perm); 658 done2: 659 mtx_unlock(&msq_mtx); 660 return (error); 661 } 662 663 #ifndef _SYS_SYSPROTO_H_ 664 struct msgsnd_args { 665 int msqid; 666 const void *msgp; 667 size_t msgsz; 668 int msgflg; 669 }; 670 #endif 671 672 /* 673 * MPSAFE 674 */ 675 int 676 msgsnd(td, uap) 677 struct thread *td; 678 register struct msgsnd_args *uap; 679 { 680 int msqid = uap->msqid; 681 const void *user_msgp = uap->msgp; 682 size_t msgsz = uap->msgsz; 683 int msgflg = uap->msgflg; 684 int segs_needed, error = 0; 685 register struct msqid_kernel *msqkptr; 686 register struct msg *msghdr; 687 short next; 688 689 DPRINTF(("call to msgsnd(%d, 0x%x, %d, %d)\n", msqid, user_msgp, msgsz, 690 msgflg)); 691 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 692 return (ENOSYS); 693 694 mtx_lock(&msq_mtx); 695 msqid = IPCID_TO_IX(msqid); 696 697 if (msqid < 0 || msqid >= msginfo.msgmni) { 698 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqid, 699 msginfo.msgmni)); 700 error = EINVAL; 701 goto done2; 702 } 703 704 msqkptr = &msqids[msqid]; 705 if (msqkptr->u.msg_qbytes == 0) { 706 DPRINTF(("no such message queue id\n")); 707 error = EINVAL; 708 goto done2; 709 } 710 if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) { 711 DPRINTF(("wrong sequence number\n")); 712 error = EINVAL; 713 goto done2; 714 } 715 716 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_W))) { 717 DPRINTF(("requester doesn't have write access\n")); 718 goto done2; 719 } 720 721 #ifdef MAC 722 error = mac_check_sysv_msqsnd(td->td_ucred, msqkptr); 723 if (error != 0) 724 goto done2; 725 #endif 726 727 segs_needed = (msgsz + msginfo.msgssz - 1) / msginfo.msgssz; 728 DPRINTF(("msgsz=%d, msgssz=%d, segs_needed=%d\n", msgsz, msginfo.msgssz, 729 segs_needed)); 730 for (;;) { 731 int need_more_resources = 0; 732 733 /* 734 * check msgsz 735 * (inside this loop in case msg_qbytes changes while we sleep) 736 */ 737 738 if (msgsz > msqkptr->u.msg_qbytes) { 739 DPRINTF(("msgsz > msqkptr->u.msg_qbytes\n")); 740 error = EINVAL; 741 goto done2; 742 } 743 744 if (msqkptr->u.msg_perm.mode & MSG_LOCKED) { 745 DPRINTF(("msqid is locked\n")); 746 need_more_resources = 1; 747 } 748 if (msgsz + msqkptr->u.msg_cbytes > msqkptr->u.msg_qbytes) { 749 DPRINTF(("msgsz + msg_cbytes > msg_qbytes\n")); 750 need_more_resources = 1; 751 } 752 if (segs_needed > nfree_msgmaps) { 753 DPRINTF(("segs_needed > nfree_msgmaps\n")); 754 need_more_resources = 1; 755 } 756 if (free_msghdrs == NULL) { 757 DPRINTF(("no more msghdrs\n")); 758 need_more_resources = 1; 759 } 760 761 if (need_more_resources) { 762 int we_own_it; 763 764 if ((msgflg & IPC_NOWAIT) != 0) { 765 DPRINTF(("need more resources but caller " 766 "doesn't want to wait\n")); 767 error = EAGAIN; 768 goto done2; 769 } 770 771 if ((msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0) { 772 DPRINTF(("we don't own the msqid_ds\n")); 773 we_own_it = 0; 774 } else { 775 /* Force later arrivals to wait for our 776 request */ 777 DPRINTF(("we own the msqid_ds\n")); 778 msqkptr->u.msg_perm.mode |= MSG_LOCKED; 779 we_own_it = 1; 780 } 781 DPRINTF(("goodnight\n")); 782 error = msleep(msqkptr, &msq_mtx, (PZERO - 4) | PCATCH, 783 "msgwait", 0); 784 DPRINTF(("good morning, error=%d\n", error)); 785 if (we_own_it) 786 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED; 787 if (error != 0) { 788 DPRINTF(("msgsnd: interrupted system call\n")); 789 error = EINTR; 790 goto done2; 791 } 792 793 /* 794 * Make sure that the msq queue still exists 795 */ 796 797 if (msqkptr->u.msg_qbytes == 0) { 798 DPRINTF(("msqid deleted\n")); 799 error = EIDRM; 800 goto done2; 801 } 802 803 } else { 804 DPRINTF(("got all the resources that we need\n")); 805 break; 806 } 807 } 808 809 /* 810 * We have the resources that we need. 811 * Make sure! 812 */ 813 814 if (msqkptr->u.msg_perm.mode & MSG_LOCKED) 815 panic("msg_perm.mode & MSG_LOCKED"); 816 if (segs_needed > nfree_msgmaps) 817 panic("segs_needed > nfree_msgmaps"); 818 if (msgsz + msqkptr->u.msg_cbytes > msqkptr->u.msg_qbytes) 819 panic("msgsz + msg_cbytes > msg_qbytes"); 820 if (free_msghdrs == NULL) 821 panic("no more msghdrs"); 822 823 /* 824 * Re-lock the msqid_ds in case we page-fault when copying in the 825 * message 826 */ 827 828 if ((msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0) 829 panic("msqid_ds is already locked"); 830 msqkptr->u.msg_perm.mode |= MSG_LOCKED; 831 832 /* 833 * Allocate a message header 834 */ 835 836 msghdr = free_msghdrs; 837 free_msghdrs = msghdr->msg_next; 838 msghdr->msg_spot = -1; 839 msghdr->msg_ts = msgsz; 840 #ifdef MAC 841 /* 842 * XXXMAC: Should the mac_check_sysv_msgmsq check follow here 843 * immediately? Or, should it be checked just before the msg is 844 * enqueued in the msgq (as it is done now)? 845 */ 846 mac_create_sysv_msgmsg(td->td_ucred, msqkptr, msghdr); 847 #endif 848 849 /* 850 * Allocate space for the message 851 */ 852 853 while (segs_needed > 0) { 854 if (nfree_msgmaps <= 0) 855 panic("not enough msgmaps"); 856 if (free_msgmaps == -1) 857 panic("nil free_msgmaps"); 858 next = free_msgmaps; 859 if (next <= -1) 860 panic("next too low #1"); 861 if (next >= msginfo.msgseg) 862 panic("next out of range #1"); 863 DPRINTF(("allocating segment %d to message\n", next)); 864 free_msgmaps = msgmaps[next].next; 865 nfree_msgmaps--; 866 msgmaps[next].next = msghdr->msg_spot; 867 msghdr->msg_spot = next; 868 segs_needed--; 869 } 870 871 /* 872 * Copy in the message type 873 */ 874 875 mtx_unlock(&msq_mtx); 876 if ((error = copyin(user_msgp, &msghdr->msg_type, 877 sizeof(msghdr->msg_type))) != 0) { 878 mtx_lock(&msq_mtx); 879 DPRINTF(("error %d copying the message type\n", error)); 880 msg_freehdr(msghdr); 881 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED; 882 wakeup(msqkptr); 883 goto done2; 884 } 885 mtx_lock(&msq_mtx); 886 user_msgp = (const char *)user_msgp + sizeof(msghdr->msg_type); 887 888 /* 889 * Validate the message type 890 */ 891 892 if (msghdr->msg_type < 1) { 893 msg_freehdr(msghdr); 894 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED; 895 wakeup(msqkptr); 896 DPRINTF(("mtype (%d) < 1\n", msghdr->msg_type)); 897 error = EINVAL; 898 goto done2; 899 } 900 901 /* 902 * Copy in the message body 903 */ 904 905 next = msghdr->msg_spot; 906 while (msgsz > 0) { 907 size_t tlen; 908 if (msgsz > msginfo.msgssz) 909 tlen = msginfo.msgssz; 910 else 911 tlen = msgsz; 912 if (next <= -1) 913 panic("next too low #2"); 914 if (next >= msginfo.msgseg) 915 panic("next out of range #2"); 916 mtx_unlock(&msq_mtx); 917 if ((error = copyin(user_msgp, &msgpool[next * msginfo.msgssz], 918 tlen)) != 0) { 919 mtx_lock(&msq_mtx); 920 DPRINTF(("error %d copying in message segment\n", 921 error)); 922 msg_freehdr(msghdr); 923 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED; 924 wakeup(msqkptr); 925 goto done2; 926 } 927 mtx_lock(&msq_mtx); 928 msgsz -= tlen; 929 user_msgp = (const char *)user_msgp + tlen; 930 next = msgmaps[next].next; 931 } 932 if (next != -1) 933 panic("didn't use all the msg segments"); 934 935 /* 936 * We've got the message. Unlock the msqid_ds. 937 */ 938 939 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED; 940 941 /* 942 * Make sure that the msqid_ds is still allocated. 943 */ 944 945 if (msqkptr->u.msg_qbytes == 0) { 946 msg_freehdr(msghdr); 947 wakeup(msqkptr); 948 error = EIDRM; 949 goto done2; 950 } 951 952 #ifdef MAC 953 /* 954 * Note: Since the task/thread allocates the msghdr and usually 955 * primes it with its own MAC label, for a majority of policies, it 956 * won't be necessary to check whether the msghdr has access 957 * permissions to the msgq. The mac_check_sysv_msqsnd check would 958 * suffice in that case. However, this hook may be required where 959 * individual policies derive a non-identical label for the msghdr 960 * from the current thread label and may want to check the msghdr 961 * enqueue permissions, along with read/write permissions to the 962 * msgq. 963 */ 964 error = mac_check_sysv_msgmsq(td->td_ucred, msghdr, msqkptr); 965 if (error != 0) { 966 msg_freehdr(msghdr); 967 wakeup(msqkptr); 968 goto done2; 969 } 970 #endif 971 972 /* 973 * Put the message into the queue 974 */ 975 if (msqkptr->u.msg_first == NULL) { 976 msqkptr->u.msg_first = msghdr; 977 msqkptr->u.msg_last = msghdr; 978 } else { 979 msqkptr->u.msg_last->msg_next = msghdr; 980 msqkptr->u.msg_last = msghdr; 981 } 982 msqkptr->u.msg_last->msg_next = NULL; 983 984 msqkptr->u.msg_cbytes += msghdr->msg_ts; 985 msqkptr->u.msg_qnum++; 986 msqkptr->u.msg_lspid = td->td_proc->p_pid; 987 msqkptr->u.msg_stime = time_second; 988 989 wakeup(msqkptr); 990 td->td_retval[0] = 0; 991 done2: 992 mtx_unlock(&msq_mtx); 993 return (error); 994 } 995 996 #ifndef _SYS_SYSPROTO_H_ 997 struct msgrcv_args { 998 int msqid; 999 void *msgp; 1000 size_t msgsz; 1001 long msgtyp; 1002 int msgflg; 1003 }; 1004 #endif 1005 1006 /* 1007 * MPSAFE 1008 */ 1009 int 1010 msgrcv(td, uap) 1011 struct thread *td; 1012 register struct msgrcv_args *uap; 1013 { 1014 int msqid = uap->msqid; 1015 void *user_msgp = uap->msgp; 1016 size_t msgsz = uap->msgsz; 1017 long msgtyp = uap->msgtyp; 1018 int msgflg = uap->msgflg; 1019 size_t len; 1020 register struct msqid_kernel *msqkptr; 1021 register struct msg *msghdr; 1022 int error = 0; 1023 short next; 1024 1025 DPRINTF(("call to msgrcv(%d, 0x%x, %d, %ld, %d)\n", msqid, user_msgp, 1026 msgsz, msgtyp, msgflg)); 1027 1028 if (!jail_sysvipc_allowed && jailed(td->td_ucred)) 1029 return (ENOSYS); 1030 1031 msqid = IPCID_TO_IX(msqid); 1032 1033 if (msqid < 0 || msqid >= msginfo.msgmni) { 1034 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqid, 1035 msginfo.msgmni)); 1036 return (EINVAL); 1037 } 1038 1039 msqkptr = &msqids[msqid]; 1040 mtx_lock(&msq_mtx); 1041 if (msqkptr->u.msg_qbytes == 0) { 1042 DPRINTF(("no such message queue id\n")); 1043 error = EINVAL; 1044 goto done2; 1045 } 1046 if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) { 1047 DPRINTF(("wrong sequence number\n")); 1048 error = EINVAL; 1049 goto done2; 1050 } 1051 1052 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_R))) { 1053 DPRINTF(("requester doesn't have read access\n")); 1054 goto done2; 1055 } 1056 1057 #ifdef MAC 1058 error = mac_check_sysv_msqrcv(td->td_ucred, msqkptr); 1059 if (error != 0) 1060 goto done2; 1061 #endif 1062 1063 msghdr = NULL; 1064 while (msghdr == NULL) { 1065 if (msgtyp == 0) { 1066 msghdr = msqkptr->u.msg_first; 1067 if (msghdr != NULL) { 1068 if (msgsz < msghdr->msg_ts && 1069 (msgflg & MSG_NOERROR) == 0) { 1070 DPRINTF(("first message on the queue " 1071 "is too big (want %d, got %d)\n", 1072 msgsz, msghdr->msg_ts)); 1073 error = E2BIG; 1074 goto done2; 1075 } 1076 #ifdef MAC 1077 error = mac_check_sysv_msgrcv(td->td_ucred, 1078 msghdr); 1079 if (error != 0) 1080 goto done2; 1081 #endif 1082 if (msqkptr->u.msg_first == msqkptr->u.msg_last) { 1083 msqkptr->u.msg_first = NULL; 1084 msqkptr->u.msg_last = NULL; 1085 } else { 1086 msqkptr->u.msg_first = msghdr->msg_next; 1087 if (msqkptr->u.msg_first == NULL) 1088 panic("msg_first/last screwed up #1"); 1089 } 1090 } 1091 } else { 1092 struct msg *previous; 1093 struct msg **prev; 1094 1095 previous = NULL; 1096 prev = &(msqkptr->u.msg_first); 1097 while ((msghdr = *prev) != NULL) { 1098 /* 1099 * Is this message's type an exact match or is 1100 * this message's type less than or equal to 1101 * the absolute value of a negative msgtyp? 1102 * Note that the second half of this test can 1103 * NEVER be true if msgtyp is positive since 1104 * msg_type is always positive! 1105 */ 1106 1107 if (msgtyp == msghdr->msg_type || 1108 msghdr->msg_type <= -msgtyp) { 1109 DPRINTF(("found message type %d, " 1110 "requested %d\n", 1111 msghdr->msg_type, msgtyp)); 1112 if (msgsz < msghdr->msg_ts && 1113 (msgflg & MSG_NOERROR) == 0) { 1114 DPRINTF(("requested message " 1115 "on the queue is too big " 1116 "(want %d, got %d)\n", 1117 msgsz, msghdr->msg_ts)); 1118 error = E2BIG; 1119 goto done2; 1120 } 1121 #ifdef MAC 1122 error = mac_check_sysv_msgrcv( 1123 td->td_ucred, msghdr); 1124 if (error != 0) 1125 goto done2; 1126 #endif 1127 *prev = msghdr->msg_next; 1128 if (msghdr == msqkptr->u.msg_last) { 1129 if (previous == NULL) { 1130 if (prev != 1131 &msqkptr->u.msg_first) 1132 panic("msg_first/last screwed up #2"); 1133 msqkptr->u.msg_first = 1134 NULL; 1135 msqkptr->u.msg_last = 1136 NULL; 1137 } else { 1138 if (prev == 1139 &msqkptr->u.msg_first) 1140 panic("msg_first/last screwed up #3"); 1141 msqkptr->u.msg_last = 1142 previous; 1143 } 1144 } 1145 break; 1146 } 1147 previous = msghdr; 1148 prev = &(msghdr->msg_next); 1149 } 1150 } 1151 1152 /* 1153 * We've either extracted the msghdr for the appropriate 1154 * message or there isn't one. 1155 * If there is one then bail out of this loop. 1156 */ 1157 1158 if (msghdr != NULL) 1159 break; 1160 1161 /* 1162 * Hmph! No message found. Does the user want to wait? 1163 */ 1164 1165 if ((msgflg & IPC_NOWAIT) != 0) { 1166 DPRINTF(("no appropriate message found (msgtyp=%d)\n", 1167 msgtyp)); 1168 /* The SVID says to return ENOMSG. */ 1169 error = ENOMSG; 1170 goto done2; 1171 } 1172 1173 /* 1174 * Wait for something to happen 1175 */ 1176 1177 DPRINTF(("msgrcv: goodnight\n")); 1178 error = msleep(msqkptr, &msq_mtx, (PZERO - 4) | PCATCH, 1179 "msgwait", 0); 1180 DPRINTF(("msgrcv: good morning (error=%d)\n", error)); 1181 1182 if (error != 0) { 1183 DPRINTF(("msgsnd: interrupted system call\n")); 1184 error = EINTR; 1185 goto done2; 1186 } 1187 1188 /* 1189 * Make sure that the msq queue still exists 1190 */ 1191 1192 if (msqkptr->u.msg_qbytes == 0 || 1193 msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) { 1194 DPRINTF(("msqid deleted\n")); 1195 error = EIDRM; 1196 goto done2; 1197 } 1198 } 1199 1200 /* 1201 * Return the message to the user. 1202 * 1203 * First, do the bookkeeping (before we risk being interrupted). 1204 */ 1205 1206 msqkptr->u.msg_cbytes -= msghdr->msg_ts; 1207 msqkptr->u.msg_qnum--; 1208 msqkptr->u.msg_lrpid = td->td_proc->p_pid; 1209 msqkptr->u.msg_rtime = time_second; 1210 1211 /* 1212 * Make msgsz the actual amount that we'll be returning. 1213 * Note that this effectively truncates the message if it is too long 1214 * (since msgsz is never increased). 1215 */ 1216 1217 DPRINTF(("found a message, msgsz=%d, msg_ts=%d\n", msgsz, 1218 msghdr->msg_ts)); 1219 if (msgsz > msghdr->msg_ts) 1220 msgsz = msghdr->msg_ts; 1221 1222 /* 1223 * Return the type to the user. 1224 */ 1225 1226 mtx_unlock(&msq_mtx); 1227 error = copyout(&(msghdr->msg_type), user_msgp, 1228 sizeof(msghdr->msg_type)); 1229 mtx_lock(&msq_mtx); 1230 if (error != 0) { 1231 DPRINTF(("error (%d) copying out message type\n", error)); 1232 msg_freehdr(msghdr); 1233 wakeup(msqkptr); 1234 goto done2; 1235 } 1236 user_msgp = (char *)user_msgp + sizeof(msghdr->msg_type); 1237 1238 /* 1239 * Return the segments to the user 1240 */ 1241 1242 next = msghdr->msg_spot; 1243 for (len = 0; len < msgsz; len += msginfo.msgssz) { 1244 size_t tlen; 1245 1246 if (msgsz - len > msginfo.msgssz) 1247 tlen = msginfo.msgssz; 1248 else 1249 tlen = msgsz - len; 1250 if (next <= -1) 1251 panic("next too low #3"); 1252 if (next >= msginfo.msgseg) 1253 panic("next out of range #3"); 1254 mtx_unlock(&msq_mtx); 1255 error = copyout(&msgpool[next * msginfo.msgssz], 1256 user_msgp, tlen); 1257 mtx_lock(&msq_mtx); 1258 if (error != 0) { 1259 DPRINTF(("error (%d) copying out message segment\n", 1260 error)); 1261 msg_freehdr(msghdr); 1262 wakeup(msqkptr); 1263 goto done2; 1264 } 1265 user_msgp = (char *)user_msgp + tlen; 1266 next = msgmaps[next].next; 1267 } 1268 1269 /* 1270 * Done, return the actual number of bytes copied out. 1271 */ 1272 1273 msg_freehdr(msghdr); 1274 wakeup(msqkptr); 1275 td->td_retval[0] = msgsz; 1276 done2: 1277 mtx_unlock(&msq_mtx); 1278 return (error); 1279 } 1280 1281 static int 1282 sysctl_msqids(SYSCTL_HANDLER_ARGS) 1283 { 1284 1285 return (SYSCTL_OUT(req, msqids, 1286 sizeof(struct msqid_kernel) * msginfo.msgmni)); 1287 } 1288 1289 SYSCTL_INT(_kern_ipc, OID_AUTO, msgmax, CTLFLAG_RD, &msginfo.msgmax, 0, 1290 "Maximum message size"); 1291 SYSCTL_INT(_kern_ipc, OID_AUTO, msgmni, CTLFLAG_RDTUN, &msginfo.msgmni, 0, 1292 "Number of message queue identifiers"); 1293 SYSCTL_INT(_kern_ipc, OID_AUTO, msgmnb, CTLFLAG_RDTUN, &msginfo.msgmnb, 0, 1294 "Maximum number of bytes in a queue"); 1295 SYSCTL_INT(_kern_ipc, OID_AUTO, msgtql, CTLFLAG_RDTUN, &msginfo.msgtql, 0, 1296 "Maximum number of messages in the system"); 1297 SYSCTL_INT(_kern_ipc, OID_AUTO, msgssz, CTLFLAG_RDTUN, &msginfo.msgssz, 0, 1298 "Size of a message segment"); 1299 SYSCTL_INT(_kern_ipc, OID_AUTO, msgseg, CTLFLAG_RDTUN, &msginfo.msgseg, 0, 1300 "Number of message segments"); 1301 SYSCTL_PROC(_kern_ipc, OID_AUTO, msqids, CTLFLAG_RD, 1302 NULL, 0, sysctl_msqids, "", "Message queue IDs"); 1303