FreeBSD/Linux Kernel Cross Reference
sys/kern/sysv_msg.c
1 /* $NetBSD: sysv_msg.c,v 1.58.4.1 2009/02/02 20:00:42 snj 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 1.58.4.1 2009/02/02 20:00:42 snj 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 *)((uintptr_t)msgpool + ALIGN(msginfo.msgmax));
125 msghdrs = (void *)((uintptr_t)msgmaps +
126 ALIGN(msginfo.msgseg * sizeof(struct msgmap)));
127 msqs = (void *)((uintptr_t)msghdrs +
128 ALIGN(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 *)((uintptr_t)new_msgpool + ALIGN(newmsgmax));
222 new_msghdrs = (void *)((uintptr_t)new_msgmaps +
223 ALIGN(newmsgseg * sizeof(struct msgmap)));
224 new_msqs = (void *)((uintptr_t)new_msghdrs +
225 ALIGN(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 error = EINVAL;
855 goto unlock;
856 }
857
858 /*
859 * Copy in the message body
860 */
861
862 next = msghdr->msg_spot;
863 while (msgsz > 0) {
864 size_t tlen;
865 KASSERT(next > -1);
866 KASSERT(next < msginfo.msgseg);
867
868 if (msgsz > msginfo.msgssz)
869 tlen = msginfo.msgssz;
870 else
871 tlen = msgsz;
872 mutex_exit(&msgmutex);
873 error = copyin(user_msgp, &msgpool[next * msginfo.msgssz], tlen);
874 mutex_enter(&msgmutex);
875 if (error != 0) {
876 MSG_PRINTF(("error %d copying in message segment\n",
877 error));
878 msg_freehdr(msghdr);
879 msqptr->msg_perm.mode &= ~MSG_LOCKED;
880 cv_broadcast(&msq->msq_cv);
881 goto unlock;
882 }
883 msgsz -= tlen;
884 user_msgp += tlen;
885 next = msgmaps[next].next;
886 }
887 KASSERT(next == -1);
888
889 /*
890 * We've got the message. Unlock the msqid_ds.
891 */
892
893 msqptr->msg_perm.mode &= ~MSG_LOCKED;
894
895 /*
896 * Make sure that the msqid_ds is still allocated.
897 */
898
899 if (msqptr->msg_qbytes == 0) {
900 msg_freehdr(msghdr);
901 cv_broadcast(&msq->msq_cv);
902 error = EIDRM;
903 goto unlock;
904 }
905
906 /*
907 * Put the message into the queue
908 */
909
910 if (msqptr->_msg_first == NULL) {
911 msqptr->_msg_first = msghdr;
912 msqptr->_msg_last = msghdr;
913 } else {
914 msqptr->_msg_last->msg_next = msghdr;
915 msqptr->_msg_last = msghdr;
916 }
917 msqptr->_msg_last->msg_next = NULL;
918
919 msqptr->_msg_cbytes += msghdr->msg_ts;
920 msqptr->msg_qnum++;
921 msqptr->msg_lspid = l->l_proc->p_pid;
922 msqptr->msg_stime = time_second;
923
924 cv_broadcast(&msq->msq_cv);
925
926 unlock:
927 mutex_exit(&msgmutex);
928 return error;
929 }
930
931 int
932 sys_msgrcv(struct lwp *l, const struct sys_msgrcv_args *uap, register_t *retval)
933 {
934 /* {
935 syscallarg(int) msqid;
936 syscallarg(void *) msgp;
937 syscallarg(size_t) msgsz;
938 syscallarg(long) msgtyp;
939 syscallarg(int) msgflg;
940 } */
941
942 return msgrcv1(l, SCARG(uap, msqid), SCARG(uap, msgp),
943 SCARG(uap, msgsz), SCARG(uap, msgtyp), SCARG(uap, msgflg),
944 sizeof(long), copyout, retval);
945 }
946
947 int
948 msgrcv1(struct lwp *l, int msqidr, char *user_msgp, size_t msgsz, long msgtyp,
949 int msgflg, size_t typesz, copyout_t put_type, register_t *retval)
950 {
951 size_t len;
952 kauth_cred_t cred = l->l_cred;
953 struct msqid_ds *msqptr;
954 struct __msg *msghdr;
955 int error = 0, msqid;
956 kmsq_t *msq;
957 short next;
958
959 MSG_PRINTF(("call to msgrcv(%d, %p, %lld, %ld, %d)\n", msqid,
960 user_msgp, (long long)msgsz, msgtyp, msgflg));
961 restart:
962 msqid = IPCID_TO_IX(msqidr);
963
964 mutex_enter(&msgmutex);
965 /* In case of reallocation, we will wait for completion */
966 while (__predict_false(msg_realloc_state))
967 cv_wait(&msg_realloc_cv, &msgmutex);
968
969 if (msqid < 0 || msqid >= msginfo.msgmni) {
970 MSG_PRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqid,
971 msginfo.msgmni));
972 error = EINVAL;
973 goto unlock;
974 }
975
976 msq = &msqs[msqid];
977 msqptr = &msq->msq_u;
978
979 if (msqptr->msg_qbytes == 0) {
980 MSG_PRINTF(("no such message queue id\n"));
981 error = EINVAL;
982 goto unlock;
983 }
984 if (msqptr->msg_perm._seq != IPCID_TO_SEQ(msqidr)) {
985 MSG_PRINTF(("wrong sequence number\n"));
986 error = EINVAL;
987 goto unlock;
988 }
989
990 if ((error = ipcperm(cred, &msqptr->msg_perm, IPC_R))) {
991 MSG_PRINTF(("requester doesn't have read access\n"));
992 goto unlock;
993 }
994
995 msghdr = NULL;
996 while (msghdr == NULL) {
997 if (msgtyp == 0) {
998 msghdr = msqptr->_msg_first;
999 if (msghdr != NULL) {
1000 if (msgsz < msghdr->msg_ts &&
1001 (msgflg & MSG_NOERROR) == 0) {
1002 MSG_PRINTF(("first msg on the queue "
1003 "is too big (want %lld, got %d)\n",
1004 (long long)msgsz, msghdr->msg_ts));
1005 error = E2BIG;
1006 goto unlock;
1007 }
1008 if (msqptr->_msg_first == msqptr->_msg_last) {
1009 msqptr->_msg_first = NULL;
1010 msqptr->_msg_last = NULL;
1011 } else {
1012 msqptr->_msg_first = msghdr->msg_next;
1013 KASSERT(msqptr->_msg_first != NULL);
1014 }
1015 }
1016 } else {
1017 struct __msg *previous;
1018 struct __msg **prev;
1019
1020 for (previous = NULL, prev = &msqptr->_msg_first;
1021 (msghdr = *prev) != NULL;
1022 previous = msghdr, prev = &msghdr->msg_next) {
1023 /*
1024 * Is this message's type an exact match or is
1025 * this message's type less than or equal to
1026 * the absolute value of a negative msgtyp?
1027 * Note that the second half of this test can
1028 * NEVER be true if msgtyp is positive since
1029 * msg_type is always positive!
1030 */
1031
1032 if (msgtyp != msghdr->msg_type &&
1033 msghdr->msg_type > -msgtyp)
1034 continue;
1035
1036 MSG_PRINTF(("found message type %ld, requested %ld\n",
1037 msghdr->msg_type, msgtyp));
1038 if (msgsz < msghdr->msg_ts &&
1039 (msgflg & MSG_NOERROR) == 0) {
1040 MSG_PRINTF(("requested message on the queue "
1041 "is too big (want %lld, got %d)\n",
1042 (long long)msgsz, msghdr->msg_ts));
1043 error = E2BIG;
1044 goto unlock;
1045 }
1046 *prev = msghdr->msg_next;
1047 if (msghdr != msqptr->_msg_last)
1048 break;
1049 if (previous == NULL) {
1050 KASSERT(prev == &msqptr->_msg_first);
1051 msqptr->_msg_first = NULL;
1052 msqptr->_msg_last = NULL;
1053 } else {
1054 KASSERT(prev != &msqptr->_msg_first);
1055 msqptr->_msg_last = previous;
1056 }
1057 break;
1058 }
1059 }
1060
1061 /*
1062 * We've either extracted the msghdr for the appropriate
1063 * message or there isn't one.
1064 * If there is one then bail out of this loop.
1065 */
1066 if (msghdr != NULL)
1067 break;
1068
1069 /*
1070 * Hmph! No message found. Does the user want to wait?
1071 */
1072
1073 if ((msgflg & IPC_NOWAIT) != 0) {
1074 MSG_PRINTF(("no appropriate message found (msgtyp=%ld)\n",
1075 msgtyp));
1076 error = ENOMSG;
1077 goto unlock;
1078 }
1079
1080 /*
1081 * Wait for something to happen
1082 */
1083
1084 msg_waiters++;
1085 MSG_PRINTF(("msgrcv: goodnight\n"));
1086 error = cv_wait_sig(&msq->msq_cv, &msgmutex);
1087 MSG_PRINTF(("msgrcv: good morning (error=%d)\n", error));
1088 msg_waiters--;
1089
1090 /*
1091 * In case of such state, notify reallocator and
1092 * restart the call.
1093 */
1094 if (msg_realloc_state) {
1095 cv_broadcast(&msg_realloc_cv);
1096 mutex_exit(&msgmutex);
1097 goto restart;
1098 }
1099
1100 if (error != 0) {
1101 MSG_PRINTF(("msgsnd: interrupted system call\n"));
1102 error = EINTR;
1103 goto unlock;
1104 }
1105
1106 /*
1107 * Make sure that the msq queue still exists
1108 */
1109
1110 if (msqptr->msg_qbytes == 0 ||
1111 msqptr->msg_perm._seq != IPCID_TO_SEQ(msqidr)) {
1112 MSG_PRINTF(("msqid deleted\n"));
1113 error = EIDRM;
1114 goto unlock;
1115 }
1116 }
1117
1118 /*
1119 * Return the message to the user.
1120 *
1121 * First, do the bookkeeping (before we risk being interrupted).
1122 */
1123
1124 msqptr->_msg_cbytes -= msghdr->msg_ts;
1125 msqptr->msg_qnum--;
1126 msqptr->msg_lrpid = l->l_proc->p_pid;
1127 msqptr->msg_rtime = time_second;
1128
1129 /*
1130 * Make msgsz the actual amount that we'll be returning.
1131 * Note that this effectively truncates the message if it is too long
1132 * (since msgsz is never increased).
1133 */
1134
1135 MSG_PRINTF(("found a message, msgsz=%lld, msg_ts=%d\n",
1136 (long long)msgsz, msghdr->msg_ts));
1137 if (msgsz > msghdr->msg_ts)
1138 msgsz = msghdr->msg_ts;
1139
1140 /*
1141 * Return the type to the user.
1142 */
1143 mutex_exit(&msgmutex);
1144 error = (*put_type)(&msghdr->msg_type, user_msgp, typesz);
1145 mutex_enter(&msgmutex);
1146 if (error != 0) {
1147 MSG_PRINTF(("error (%d) copying out message type\n", error));
1148 msg_freehdr(msghdr);
1149 cv_broadcast(&msq->msq_cv);
1150 goto unlock;
1151 }
1152 user_msgp += typesz;
1153
1154 /*
1155 * Return the segments to the user
1156 */
1157
1158 next = msghdr->msg_spot;
1159 for (len = 0; len < msgsz; len += msginfo.msgssz) {
1160 size_t tlen;
1161 KASSERT(next > -1);
1162 KASSERT(next < msginfo.msgseg);
1163
1164 if (msgsz - len > msginfo.msgssz)
1165 tlen = msginfo.msgssz;
1166 else
1167 tlen = msgsz - len;
1168 mutex_exit(&msgmutex);
1169 error = copyout(&msgpool[next * msginfo.msgssz],
1170 user_msgp, tlen);
1171 mutex_enter(&msgmutex);
1172 if (error != 0) {
1173 MSG_PRINTF(("error (%d) copying out message segment\n",
1174 error));
1175 msg_freehdr(msghdr);
1176 cv_broadcast(&msq->msq_cv);
1177 goto unlock;
1178 }
1179 user_msgp += tlen;
1180 next = msgmaps[next].next;
1181 }
1182
1183 /*
1184 * Done, return the actual number of bytes copied out.
1185 */
1186
1187 msg_freehdr(msghdr);
1188 cv_broadcast(&msq->msq_cv);
1189 *retval = msgsz;
1190
1191 unlock:
1192 mutex_exit(&msgmutex);
1193 return error;
1194 }
1195
1196 /*
1197 * Sysctl initialization and nodes.
1198 */
1199
1200 static int
1201 sysctl_ipc_msgmni(SYSCTLFN_ARGS)
1202 {
1203 int newsize, error;
1204 struct sysctlnode node;
1205 node = *rnode;
1206 node.sysctl_data = &newsize;
1207
1208 newsize = msginfo.msgmni;
1209 error = sysctl_lookup(SYSCTLFN_CALL(&node));
1210 if (error || newp == NULL)
1211 return error;
1212
1213 sysctl_unlock();
1214 error = msgrealloc(newsize, msginfo.msgseg);
1215 sysctl_relock();
1216 return error;
1217 }
1218
1219 static int
1220 sysctl_ipc_msgseg(SYSCTLFN_ARGS)
1221 {
1222 int newsize, error;
1223 struct sysctlnode node;
1224 node = *rnode;
1225 node.sysctl_data = &newsize;
1226
1227 newsize = msginfo.msgseg;
1228 error = sysctl_lookup(SYSCTLFN_CALL(&node));
1229 if (error || newp == NULL)
1230 return error;
1231
1232 sysctl_unlock();
1233 error = msgrealloc(msginfo.msgmni, newsize);
1234 sysctl_relock();
1235 return error;
1236 }
1237
1238 SYSCTL_SETUP(sysctl_ipc_msg_setup, "sysctl kern.ipc subtree setup")
1239 {
1240 const struct sysctlnode *node = NULL;
1241
1242 sysctl_createv(clog, 0, NULL, NULL,
1243 CTLFLAG_PERMANENT,
1244 CTLTYPE_NODE, "kern", NULL,
1245 NULL, 0, NULL, 0,
1246 CTL_KERN, CTL_EOL);
1247 sysctl_createv(clog, 0, NULL, &node,
1248 CTLFLAG_PERMANENT,
1249 CTLTYPE_NODE, "ipc",
1250 SYSCTL_DESCR("SysV IPC options"),
1251 NULL, 0, NULL, 0,
1252 CTL_KERN, KERN_SYSVIPC, CTL_EOL);
1253
1254 if (node == NULL)
1255 return;
1256
1257 sysctl_createv(clog, 0, &node, NULL,
1258 CTLFLAG_PERMANENT | CTLFLAG_READWRITE,
1259 CTLTYPE_INT, "msgmni",
1260 SYSCTL_DESCR("Max number of message queue identifiers"),
1261 sysctl_ipc_msgmni, 0, &msginfo.msgmni, 0,
1262 CTL_CREATE, CTL_EOL);
1263 sysctl_createv(clog, 0, &node, NULL,
1264 CTLFLAG_PERMANENT | CTLFLAG_READWRITE,
1265 CTLTYPE_INT, "msgseg",
1266 SYSCTL_DESCR("Max number of number of message segments"),
1267 sysctl_ipc_msgseg, 0, &msginfo.msgseg, 0,
1268 CTL_CREATE, CTL_EOL);
1269 }
Cache object: ba131b7ff1d82b7679717d9508deb645
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