2 * Implementation of SVID messages
4 * Author: Daniel Boulet
6 * Copyright 1993 Daniel Boulet and RTMX Inc.
8 * This system call was implemented by Daniel Boulet under contract from RTMX.
10 * Redistribution and use in source forms, with and without modification,
11 * are permitted provided that this entire comment appears intact.
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.
17 * This software is provided ``AS IS'' without any warranties of any kind.
20 * Copyright (c) 2003-2005 McAfee, Inc.
21 * All rights reserved.
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
28 * Redistribution and use in source and binary forms, with or without
29 * modification, are permitted provided that the following conditions
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.
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
50 #include <sys/cdefs.h>
51 __FBSDID("$FreeBSD$");
53 #include "opt_sysvipc.h"
56 #include <sys/param.h>
57 #include <sys/systm.h>
58 #include <sys/sysproto.h>
59 #include <sys/kernel.h>
63 #include <sys/mutex.h>
64 #include <sys/module.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>
73 #include <security/mac/mac_framework.h>
75 static MALLOC_DEFINE(M_MSG, "msg", "SVID compatible message queues");
77 static void msginit(void);
78 static int msgunload(void);
79 static int sysvmsg_modload(struct module *, int, void *);
82 #define DPRINTF(a) printf a
87 static void msg_freehdr(struct msg *msghdr);
89 /* XXX casting to (sy_call_t *) is bogus, as usual. */
90 static sy_call_t *msgcalls[] = {
91 (sy_call_t *)msgctl, (sy_call_t *)msgget,
92 (sy_call_t *)msgsnd, (sy_call_t *)msgrcv
96 #define MSGSSZ 8 /* Each segment must be 2^N long */
99 #define MSGSEG 2048 /* must be less than 32767 */
101 #define MSGMAX (MSGSSZ*MSGSEG)
103 #define MSGMNB 2048 /* max # of bytes in a queue */
113 * Based on the configuration parameters described in an SVR2 (yes, two)
114 * config(1m) man page.
116 * Each message is broken up and stored in segments that are msgssz bytes
117 * long. For efficiency reasons, this should be a power of two. Also,
118 * it doesn't make sense if it is less than 8 or greater than about 256.
119 * Consequently, msginit in kern/sysv_msg.c checks that msgssz is a power of
120 * two between 8 and 1024 inclusive (and panic's if it isn't).
122 struct msginfo msginfo = {
123 MSGMAX, /* max chars in a message */
124 MSGMNI, /* # of message queue identifiers */
125 MSGMNB, /* max chars in a queue */
126 MSGTQL, /* max messages in system */
127 MSGSSZ, /* size of a message segment */
128 /* (must be small power of 2 greater than 4) */
129 MSGSEG /* number of message segments */
133 * macros to convert between msqid_ds's and msqid's.
134 * (specific to this implementation)
136 #define MSQID(ix,ds) ((ix) & 0xffff | (((ds).msg_perm.seq << 16) & 0xffff0000))
137 #define MSQID_IX(id) ((id) & 0xffff)
138 #define MSQID_SEQ(id) (((id) >> 16) & 0xffff)
141 * The rest of this file is specific to this particular implementation.
145 short next; /* next segment in buffer */
146 /* -1 -> available */
147 /* 0..(MSGSEG-1) -> index of next segment */
150 #define MSG_LOCKED 01000 /* Is this msqid_ds locked? */
152 static int nfree_msgmaps; /* # of free map entries */
153 static short free_msgmaps; /* head of linked list of free map entries */
154 static struct msg *free_msghdrs;/* list of free msg headers */
155 static char *msgpool; /* MSGMAX byte long msg buffer pool */
156 static struct msgmap *msgmaps; /* MSGSEG msgmap structures */
157 static struct msg *msghdrs; /* MSGTQL msg headers */
158 static struct msqid_kernel *msqids; /* MSGMNI msqid_kernel struct's */
159 static struct mtx msq_mtx; /* global mutex for message queues. */
166 TUNABLE_INT_FETCH("kern.ipc.msgseg", &msginfo.msgseg);
167 TUNABLE_INT_FETCH("kern.ipc.msgssz", &msginfo.msgssz);
168 msginfo.msgmax = msginfo.msgseg * msginfo.msgssz;
169 TUNABLE_INT_FETCH("kern.ipc.msgmni", &msginfo.msgmni);
170 TUNABLE_INT_FETCH("kern.ipc.msgmnb", &msginfo.msgmnb);
171 TUNABLE_INT_FETCH("kern.ipc.msgtql", &msginfo.msgtql);
173 msgpool = malloc(msginfo.msgmax, M_MSG, M_WAITOK);
175 panic("msgpool is NULL");
176 msgmaps = malloc(sizeof(struct msgmap) * msginfo.msgseg, M_MSG, M_WAITOK);
178 panic("msgmaps is NULL");
179 msghdrs = malloc(sizeof(struct msg) * msginfo.msgtql, M_MSG, M_WAITOK);
181 panic("msghdrs is NULL");
182 msqids = malloc(sizeof(struct msqid_kernel) * msginfo.msgmni, M_MSG,
185 panic("msqids is NULL");
188 * msginfo.msgssz should be a power of two for efficiency reasons.
189 * It is also pretty silly if msginfo.msgssz is less than 8
190 * or greater than about 256 so ...
194 while (i < 1024 && i != msginfo.msgssz)
196 if (i != msginfo.msgssz) {
197 DPRINTF(("msginfo.msgssz=%d (0x%x)\n", msginfo.msgssz,
199 panic("msginfo.msgssz not a small power of 2");
202 if (msginfo.msgseg > 32767) {
203 DPRINTF(("msginfo.msgseg=%d\n", msginfo.msgseg));
204 panic("msginfo.msgseg > 32767");
208 panic("msgmaps is NULL");
210 for (i = 0; i < msginfo.msgseg; i++) {
212 msgmaps[i-1].next = i;
213 msgmaps[i].next = -1; /* implies entry is available */
216 nfree_msgmaps = msginfo.msgseg;
219 panic("msghdrs is NULL");
221 for (i = 0; i < msginfo.msgtql; i++) {
222 msghdrs[i].msg_type = 0;
224 msghdrs[i-1].msg_next = &msghdrs[i];
225 msghdrs[i].msg_next = NULL;
227 mac_init_sysv_msgmsg(&msghdrs[i]);
230 free_msghdrs = &msghdrs[0];
233 panic("msqids is NULL");
235 for (i = 0; i < msginfo.msgmni; i++) {
236 msqids[i].u.msg_qbytes = 0; /* implies entry is available */
237 msqids[i].u.msg_perm.seq = 0; /* reset to a known value */
238 msqids[i].u.msg_perm.mode = 0;
240 mac_init_sysv_msgqueue(&msqids[i]);
243 mtx_init(&msq_mtx, "msq", NULL, MTX_DEF);
249 struct msqid_kernel *msqkptr;
255 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
257 * Look for an unallocated and unlocked msqid_ds.
258 * msqid_ds's can be locked by msgsnd or msgrcv while
259 * they are copying the message in/out. We can't
260 * re-use the entry until they release it.
262 msqkptr = &msqids[msqid];
263 if (msqkptr->u.msg_qbytes != 0 ||
264 (msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0)
267 if (msqid != msginfo.msgmni)
271 for (i = 0; i < msginfo.msgtql; i++)
272 mac_destroy_sysv_msgmsg(&msghdrs[i]);
273 for (msqid = 0; msqid < msginfo.msgmni; msqid++)
274 mac_destroy_sysv_msgqueue(&msqids[msqid]);
276 free(msgpool, M_MSG);
277 free(msgmaps, M_MSG);
278 free(msghdrs, M_MSG);
280 mtx_destroy(&msq_mtx);
286 sysvmsg_modload(struct module *module, int cmd, void *arg)
306 static moduledata_t sysvmsg_mod = {
312 SYSCALL_MODULE_HELPER(msgsys);
313 SYSCALL_MODULE_HELPER(msgctl);
314 SYSCALL_MODULE_HELPER(msgget);
315 SYSCALL_MODULE_HELPER(msgsnd);
316 SYSCALL_MODULE_HELPER(msgrcv);
318 DECLARE_MODULE(sysvmsg, sysvmsg_mod,
319 SI_SUB_SYSV_MSG, SI_ORDER_FIRST);
320 MODULE_VERSION(sysvmsg, 1);
323 * Entry point for all MSG calls.
328 /* XXX actually varargs. */
329 struct msgsys_args /* {
340 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
342 if (uap->which < 0 ||
343 uap->which >= sizeof(msgcalls)/sizeof(msgcalls[0]))
345 error = (*msgcalls[uap->which])(td, &uap->a2);
353 while (msghdr->msg_ts > 0) {
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;
361 msghdr->msg_spot = next;
362 if (msghdr->msg_ts >= msginfo.msgssz)
363 msghdr->msg_ts -= msginfo.msgssz;
367 if (msghdr->msg_spot != -1)
368 panic("msghdr->msg_spot != -1");
369 msghdr->msg_next = free_msghdrs;
370 free_msghdrs = msghdr;
372 mac_cleanup_sysv_msgmsg(msghdr);
376 #ifndef _SYS_SYSPROTO_H_
380 struct msqid_ds *buf;
386 register struct msgctl_args *uap;
388 int msqid = uap->msqid;
390 struct msqid_ds msqbuf;
393 DPRINTF(("call to msgctl(%d, %d, %p)\n", msqid, cmd, uap->buf));
394 if (cmd == IPC_SET &&
395 (error = copyin(uap->buf, &msqbuf, sizeof(msqbuf))) != 0)
397 error = kern_msgctl(td, msqid, cmd, &msqbuf);
398 if (cmd == IPC_STAT && error == 0)
399 error = copyout(&msqbuf, uap->buf, sizeof(struct msqid_ds));
404 kern_msgctl(td, msqid, cmd, msqbuf)
408 struct msqid_ds *msqbuf;
410 int rval, error, msqix;
411 register struct msqid_kernel *msqkptr;
413 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
416 msqix = IPCID_TO_IX(msqid);
418 if (msqix < 0 || msqix >= msginfo.msgmni) {
419 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix,
424 msqkptr = &msqids[msqix];
427 if (msqkptr->u.msg_qbytes == 0) {
428 DPRINTF(("no such msqid\n"));
432 if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
433 DPRINTF(("wrong sequence number\n"));
438 error = mac_check_sysv_msqctl(td->td_ucred, msqkptr, cmd);
451 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_M)))
456 * Check that the thread has MAC access permissions to
457 * individual msghdrs. Note: We need to do this in a
458 * separate loop because the actual loop alters the
459 * msq/msghdr info as it progresses, and there is no going
460 * back if half the way through we discover that the
461 * thread cannot free a certain msghdr. The msq will get
462 * into an inconsistent state.
464 for (msghdr = msqkptr->u.msg_first; msghdr != NULL;
465 msghdr = msghdr->msg_next) {
466 error = mac_check_sysv_msgrmid(td->td_ucred, msghdr);
472 /* Free the message headers */
473 msghdr = msqkptr->u.msg_first;
474 while (msghdr != NULL) {
475 struct msg *msghdr_tmp;
477 /* Free the segments of each message */
478 msqkptr->u.msg_cbytes -= msghdr->msg_ts;
479 msqkptr->u.msg_qnum--;
481 msghdr = msghdr->msg_next;
482 msg_freehdr(msghdr_tmp);
485 if (msqkptr->u.msg_cbytes != 0)
486 panic("msg_cbytes is screwed up");
487 if (msqkptr->u.msg_qnum != 0)
488 panic("msg_qnum is screwed up");
490 msqkptr->u.msg_qbytes = 0; /* Mark it as free */
493 mac_cleanup_sysv_msgqueue(msqkptr);
502 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_M)))
504 if (msqbuf->msg_qbytes > msqkptr->u.msg_qbytes) {
505 error = priv_check(td, PRIV_IPC_MSGSIZE);
509 if (msqbuf->msg_qbytes > msginfo.msgmnb) {
510 DPRINTF(("can't increase msg_qbytes beyond %d"
511 "(truncating)\n", msginfo.msgmnb));
512 msqbuf->msg_qbytes = msginfo.msgmnb; /* silently restrict qbytes to system limit */
514 if (msqbuf->msg_qbytes == 0) {
515 DPRINTF(("can't reduce msg_qbytes to 0\n"));
516 error = EINVAL; /* non-standard errno! */
519 msqkptr->u.msg_perm.uid = msqbuf->msg_perm.uid; /* change the owner */
520 msqkptr->u.msg_perm.gid = msqbuf->msg_perm.gid; /* change the owner */
521 msqkptr->u.msg_perm.mode = (msqkptr->u.msg_perm.mode & ~0777) |
522 (msqbuf->msg_perm.mode & 0777);
523 msqkptr->u.msg_qbytes = msqbuf->msg_qbytes;
524 msqkptr->u.msg_ctime = time_second;
528 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_R))) {
529 DPRINTF(("requester doesn't have read access\n"));
532 *msqbuf = msqkptr->u;
536 DPRINTF(("invalid command %d\n", cmd));
542 td->td_retval[0] = rval;
544 mtx_unlock(&msq_mtx);
548 #ifndef _SYS_SYSPROTO_H_
557 register struct msgget_args *uap;
559 int msqid, error = 0;
561 int msgflg = uap->msgflg;
562 struct ucred *cred = td->td_ucred;
563 register struct msqid_kernel *msqkptr = NULL;
565 DPRINTF(("msgget(0x%x, 0%o)\n", key, msgflg));
567 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
571 if (key != IPC_PRIVATE) {
572 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
573 msqkptr = &msqids[msqid];
574 if (msqkptr->u.msg_qbytes != 0 &&
575 msqkptr->u.msg_perm.key == key)
578 if (msqid < msginfo.msgmni) {
579 DPRINTF(("found public key\n"));
580 if ((msgflg & IPC_CREAT) && (msgflg & IPC_EXCL)) {
581 DPRINTF(("not exclusive\n"));
585 if ((error = ipcperm(td, &msqkptr->u.msg_perm,
587 DPRINTF(("requester doesn't have 0%o access\n",
592 error = mac_check_sysv_msqget(cred, msqkptr);
600 DPRINTF(("need to allocate the msqid_ds\n"));
601 if (key == IPC_PRIVATE || (msgflg & IPC_CREAT)) {
602 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
604 * Look for an unallocated and unlocked msqid_ds.
605 * msqid_ds's can be locked by msgsnd or msgrcv while
606 * they are copying the message in/out. We can't
607 * re-use the entry until they release it.
609 msqkptr = &msqids[msqid];
610 if (msqkptr->u.msg_qbytes == 0 &&
611 (msqkptr->u.msg_perm.mode & MSG_LOCKED) == 0)
614 if (msqid == msginfo.msgmni) {
615 DPRINTF(("no more msqid_ds's available\n"));
619 DPRINTF(("msqid %d is available\n", msqid));
620 msqkptr->u.msg_perm.key = key;
621 msqkptr->u.msg_perm.cuid = cred->cr_uid;
622 msqkptr->u.msg_perm.uid = cred->cr_uid;
623 msqkptr->u.msg_perm.cgid = cred->cr_gid;
624 msqkptr->u.msg_perm.gid = cred->cr_gid;
625 msqkptr->u.msg_perm.mode = (msgflg & 0777);
626 /* Make sure that the returned msqid is unique */
627 msqkptr->u.msg_perm.seq = (msqkptr->u.msg_perm.seq + 1) & 0x7fff;
628 msqkptr->u.msg_first = NULL;
629 msqkptr->u.msg_last = NULL;
630 msqkptr->u.msg_cbytes = 0;
631 msqkptr->u.msg_qnum = 0;
632 msqkptr->u.msg_qbytes = msginfo.msgmnb;
633 msqkptr->u.msg_lspid = 0;
634 msqkptr->u.msg_lrpid = 0;
635 msqkptr->u.msg_stime = 0;
636 msqkptr->u.msg_rtime = 0;
637 msqkptr->u.msg_ctime = time_second;
639 mac_create_sysv_msgqueue(cred, msqkptr);
642 DPRINTF(("didn't find it and wasn't asked to create it\n"));
648 /* Construct the unique msqid */
649 td->td_retval[0] = IXSEQ_TO_IPCID(msqid, msqkptr->u.msg_perm);
651 mtx_unlock(&msq_mtx);
655 #ifndef _SYS_SYSPROTO_H_
664 kern_msgsnd(td, msqid, msgp, msgsz, msgflg, mtype)
667 const void *msgp; /* XXX msgp is actually mtext. */
672 int msqix, segs_needed, error = 0;
673 register struct msqid_kernel *msqkptr;
674 register struct msg *msghdr;
677 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
681 msqix = IPCID_TO_IX(msqid);
683 if (msqix < 0 || msqix >= msginfo.msgmni) {
684 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix,
690 msqkptr = &msqids[msqix];
691 if (msqkptr->u.msg_qbytes == 0) {
692 DPRINTF(("no such message queue id\n"));
696 if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
697 DPRINTF(("wrong sequence number\n"));
702 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_W))) {
703 DPRINTF(("requester doesn't have write access\n"));
708 error = mac_check_sysv_msqsnd(td->td_ucred, msqkptr);
713 segs_needed = (msgsz + msginfo.msgssz - 1) / msginfo.msgssz;
714 DPRINTF(("msgsz=%zu, msgssz=%d, segs_needed=%d\n", msgsz,
715 msginfo.msgssz, segs_needed));
717 int need_more_resources = 0;
721 * (inside this loop in case msg_qbytes changes while we sleep)
724 if (msgsz > msqkptr->u.msg_qbytes) {
725 DPRINTF(("msgsz > msqkptr->u.msg_qbytes\n"));
730 if (msqkptr->u.msg_perm.mode & MSG_LOCKED) {
731 DPRINTF(("msqid is locked\n"));
732 need_more_resources = 1;
734 if (msgsz + msqkptr->u.msg_cbytes > msqkptr->u.msg_qbytes) {
735 DPRINTF(("msgsz + msg_cbytes > msg_qbytes\n"));
736 need_more_resources = 1;
738 if (segs_needed > nfree_msgmaps) {
739 DPRINTF(("segs_needed > nfree_msgmaps\n"));
740 need_more_resources = 1;
742 if (free_msghdrs == NULL) {
743 DPRINTF(("no more msghdrs\n"));
744 need_more_resources = 1;
747 if (need_more_resources) {
750 if ((msgflg & IPC_NOWAIT) != 0) {
751 DPRINTF(("need more resources but caller "
752 "doesn't want to wait\n"));
757 if ((msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0) {
758 DPRINTF(("we don't own the msqid_ds\n"));
761 /* Force later arrivals to wait for our
763 DPRINTF(("we own the msqid_ds\n"));
764 msqkptr->u.msg_perm.mode |= MSG_LOCKED;
767 DPRINTF(("msgsnd: goodnight\n"));
768 error = msleep(msqkptr, &msq_mtx, (PZERO - 4) | PCATCH,
770 DPRINTF(("msgsnd: good morning, error=%d\n", error));
772 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
773 if (error == EWOULDBLOCK) {
774 DPRINTF(("msgsnd: timed out\n"));
778 DPRINTF(("msgsnd: interrupted system call\n"));
784 * Make sure that the msq queue still exists
787 if (msqkptr->u.msg_qbytes == 0) {
788 DPRINTF(("msqid deleted\n"));
794 DPRINTF(("got all the resources that we need\n"));
800 * We have the resources that we need.
804 if (msqkptr->u.msg_perm.mode & MSG_LOCKED)
805 panic("msg_perm.mode & MSG_LOCKED");
806 if (segs_needed > nfree_msgmaps)
807 panic("segs_needed > nfree_msgmaps");
808 if (msgsz + msqkptr->u.msg_cbytes > msqkptr->u.msg_qbytes)
809 panic("msgsz + msg_cbytes > msg_qbytes");
810 if (free_msghdrs == NULL)
811 panic("no more msghdrs");
814 * Re-lock the msqid_ds in case we page-fault when copying in the
818 if ((msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0)
819 panic("msqid_ds is already locked");
820 msqkptr->u.msg_perm.mode |= MSG_LOCKED;
823 * Allocate a message header
826 msghdr = free_msghdrs;
827 free_msghdrs = msghdr->msg_next;
828 msghdr->msg_spot = -1;
829 msghdr->msg_ts = msgsz;
830 msghdr->msg_type = mtype;
833 * XXXMAC: Should the mac_check_sysv_msgmsq check follow here
834 * immediately? Or, should it be checked just before the msg is
835 * enqueued in the msgq (as it is done now)?
837 mac_create_sysv_msgmsg(td->td_ucred, msqkptr, msghdr);
841 * Allocate space for the message
844 while (segs_needed > 0) {
845 if (nfree_msgmaps <= 0)
846 panic("not enough msgmaps");
847 if (free_msgmaps == -1)
848 panic("nil free_msgmaps");
851 panic("next too low #1");
852 if (next >= msginfo.msgseg)
853 panic("next out of range #1");
854 DPRINTF(("allocating segment %d to message\n", next));
855 free_msgmaps = msgmaps[next].next;
857 msgmaps[next].next = msghdr->msg_spot;
858 msghdr->msg_spot = next;
863 * Validate the message type
866 if (msghdr->msg_type < 1) {
868 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
870 DPRINTF(("mtype (%ld) < 1\n", msghdr->msg_type));
876 * Copy in the message body
879 next = msghdr->msg_spot;
882 if (msgsz > msginfo.msgssz)
883 tlen = msginfo.msgssz;
887 panic("next too low #2");
888 if (next >= msginfo.msgseg)
889 panic("next out of range #2");
890 mtx_unlock(&msq_mtx);
891 if ((error = copyin(msgp, &msgpool[next * msginfo.msgssz],
894 DPRINTF(("error %d copying in message segment\n",
897 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
903 msgp = (const char *)msgp + tlen;
904 next = msgmaps[next].next;
907 panic("didn't use all the msg segments");
910 * We've got the message. Unlock the msqid_ds.
913 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
916 * Make sure that the msqid_ds is still allocated.
919 if (msqkptr->u.msg_qbytes == 0) {
928 * Note: Since the task/thread allocates the msghdr and usually
929 * primes it with its own MAC label, for a majority of policies, it
930 * won't be necessary to check whether the msghdr has access
931 * permissions to the msgq. The mac_check_sysv_msqsnd check would
932 * suffice in that case. However, this hook may be required where
933 * individual policies derive a non-identical label for the msghdr
934 * from the current thread label and may want to check the msghdr
935 * enqueue permissions, along with read/write permissions to the
938 error = mac_check_sysv_msgmsq(td->td_ucred, msghdr, msqkptr);
947 * Put the message into the queue
949 if (msqkptr->u.msg_first == NULL) {
950 msqkptr->u.msg_first = msghdr;
951 msqkptr->u.msg_last = msghdr;
953 msqkptr->u.msg_last->msg_next = msghdr;
954 msqkptr->u.msg_last = msghdr;
956 msqkptr->u.msg_last->msg_next = NULL;
958 msqkptr->u.msg_cbytes += msghdr->msg_ts;
959 msqkptr->u.msg_qnum++;
960 msqkptr->u.msg_lspid = td->td_proc->p_pid;
961 msqkptr->u.msg_stime = time_second;
964 td->td_retval[0] = 0;
966 mtx_unlock(&msq_mtx);
973 register struct msgsnd_args *uap;
978 DPRINTF(("call to msgsnd(%d, %p, %zu, %d)\n", uap->msqid, uap->msgp,
979 uap->msgsz, uap->msgflg));
981 if ((error = copyin(uap->msgp, &mtype, sizeof(mtype))) != 0) {
982 DPRINTF(("error %d copying the message type\n", error));
985 return (kern_msgsnd(td, uap->msqid,
986 (const char *)uap->msgp + sizeof(mtype),
987 uap->msgsz, uap->msgflg, mtype));
990 #ifndef _SYS_SYSPROTO_H_
1000 kern_msgrcv(td, msqid, msgp, msgsz, msgtyp, msgflg, mtype)
1003 void *msgp; /* XXX msgp is actually mtext. */
1010 register struct msqid_kernel *msqkptr;
1011 register struct msg *msghdr;
1012 int msqix, error = 0;
1015 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
1018 msqix = IPCID_TO_IX(msqid);
1020 if (msqix < 0 || msqix >= msginfo.msgmni) {
1021 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix,
1026 msqkptr = &msqids[msqix];
1028 if (msqkptr->u.msg_qbytes == 0) {
1029 DPRINTF(("no such message queue id\n"));
1033 if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
1034 DPRINTF(("wrong sequence number\n"));
1039 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_R))) {
1040 DPRINTF(("requester doesn't have read access\n"));
1045 error = mac_check_sysv_msqrcv(td->td_ucred, msqkptr);
1051 while (msghdr == NULL) {
1053 msghdr = msqkptr->u.msg_first;
1054 if (msghdr != NULL) {
1055 if (msgsz < msghdr->msg_ts &&
1056 (msgflg & MSG_NOERROR) == 0) {
1057 DPRINTF(("first message on the queue "
1058 "is too big (want %zu, got %d)\n",
1059 msgsz, msghdr->msg_ts));
1064 error = mac_check_sysv_msgrcv(td->td_ucred,
1069 if (msqkptr->u.msg_first == msqkptr->u.msg_last) {
1070 msqkptr->u.msg_first = NULL;
1071 msqkptr->u.msg_last = NULL;
1073 msqkptr->u.msg_first = msghdr->msg_next;
1074 if (msqkptr->u.msg_first == NULL)
1075 panic("msg_first/last screwed up #1");
1079 struct msg *previous;
1083 prev = &(msqkptr->u.msg_first);
1084 while ((msghdr = *prev) != NULL) {
1086 * Is this message's type an exact match or is
1087 * this message's type less than or equal to
1088 * the absolute value of a negative msgtyp?
1089 * Note that the second half of this test can
1090 * NEVER be true if msgtyp is positive since
1091 * msg_type is always positive!
1094 if (msgtyp == msghdr->msg_type ||
1095 msghdr->msg_type <= -msgtyp) {
1096 DPRINTF(("found message type %ld, "
1098 msghdr->msg_type, msgtyp));
1099 if (msgsz < msghdr->msg_ts &&
1100 (msgflg & MSG_NOERROR) == 0) {
1101 DPRINTF(("requested message "
1102 "on the queue is too big "
1103 "(want %zu, got %hu)\n",
1104 msgsz, msghdr->msg_ts));
1109 error = mac_check_sysv_msgrcv(
1110 td->td_ucred, msghdr);
1114 *prev = msghdr->msg_next;
1115 if (msghdr == msqkptr->u.msg_last) {
1116 if (previous == NULL) {
1118 &msqkptr->u.msg_first)
1119 panic("msg_first/last screwed up #2");
1120 msqkptr->u.msg_first =
1122 msqkptr->u.msg_last =
1126 &msqkptr->u.msg_first)
1127 panic("msg_first/last screwed up #3");
1128 msqkptr->u.msg_last =
1135 prev = &(msghdr->msg_next);
1140 * We've either extracted the msghdr for the appropriate
1141 * message or there isn't one.
1142 * If there is one then bail out of this loop.
1149 * Hmph! No message found. Does the user want to wait?
1152 if ((msgflg & IPC_NOWAIT) != 0) {
1153 DPRINTF(("no appropriate message found (msgtyp=%ld)\n",
1155 /* The SVID says to return ENOMSG. */
1161 * Wait for something to happen
1164 DPRINTF(("msgrcv: goodnight\n"));
1165 error = msleep(msqkptr, &msq_mtx, (PZERO - 4) | PCATCH,
1167 DPRINTF(("msgrcv: good morning (error=%d)\n", error));
1170 DPRINTF(("msgrcv: interrupted system call\n"));
1176 * Make sure that the msq queue still exists
1179 if (msqkptr->u.msg_qbytes == 0 ||
1180 msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
1181 DPRINTF(("msqid deleted\n"));
1188 * Return the message to the user.
1190 * First, do the bookkeeping (before we risk being interrupted).
1193 msqkptr->u.msg_cbytes -= msghdr->msg_ts;
1194 msqkptr->u.msg_qnum--;
1195 msqkptr->u.msg_lrpid = td->td_proc->p_pid;
1196 msqkptr->u.msg_rtime = time_second;
1199 * Make msgsz the actual amount that we'll be returning.
1200 * Note that this effectively truncates the message if it is too long
1201 * (since msgsz is never increased).
1204 DPRINTF(("found a message, msgsz=%zu, msg_ts=%hu\n", msgsz,
1206 if (msgsz > msghdr->msg_ts)
1207 msgsz = msghdr->msg_ts;
1208 *mtype = msghdr->msg_type;
1211 * Return the segments to the user
1214 next = msghdr->msg_spot;
1215 for (len = 0; len < msgsz; len += msginfo.msgssz) {
1218 if (msgsz - len > msginfo.msgssz)
1219 tlen = msginfo.msgssz;
1223 panic("next too low #3");
1224 if (next >= msginfo.msgseg)
1225 panic("next out of range #3");
1226 mtx_unlock(&msq_mtx);
1227 error = copyout(&msgpool[next * msginfo.msgssz], msgp, tlen);
1230 DPRINTF(("error (%d) copying out message segment\n",
1232 msg_freehdr(msghdr);
1236 msgp = (char *)msgp + tlen;
1237 next = msgmaps[next].next;
1241 * Done, return the actual number of bytes copied out.
1244 msg_freehdr(msghdr);
1246 td->td_retval[0] = msgsz;
1248 mtx_unlock(&msq_mtx);
1255 register struct msgrcv_args *uap;
1260 DPRINTF(("call to msgrcv(%d, %p, %zu, %ld, %d)\n", uap->msqid,
1261 uap->msgp, uap->msgsz, uap->msgtyp, uap->msgflg));
1263 if ((error = kern_msgrcv(td, uap->msqid,
1264 (char *)uap->msgp + sizeof(mtype), uap->msgsz,
1265 uap->msgtyp, uap->msgflg, &mtype)) != 0)
1267 if ((error = copyout(&mtype, uap->msgp, sizeof(mtype))) != 0)
1268 DPRINTF(("error %d copying the message type\n", error));
1273 sysctl_msqids(SYSCTL_HANDLER_ARGS)
1276 return (SYSCTL_OUT(req, msqids,
1277 sizeof(struct msqid_kernel) * msginfo.msgmni));
1280 SYSCTL_INT(_kern_ipc, OID_AUTO, msgmax, CTLFLAG_RD, &msginfo.msgmax, 0,
1281 "Maximum message size");
1282 SYSCTL_INT(_kern_ipc, OID_AUTO, msgmni, CTLFLAG_RDTUN, &msginfo.msgmni, 0,
1283 "Number of message queue identifiers");
1284 SYSCTL_INT(_kern_ipc, OID_AUTO, msgmnb, CTLFLAG_RDTUN, &msginfo.msgmnb, 0,
1285 "Maximum number of bytes in a queue");
1286 SYSCTL_INT(_kern_ipc, OID_AUTO, msgtql, CTLFLAG_RDTUN, &msginfo.msgtql, 0,
1287 "Maximum number of messages in the system");
1288 SYSCTL_INT(_kern_ipc, OID_AUTO, msgssz, CTLFLAG_RDTUN, &msginfo.msgssz, 0,
1289 "Size of a message segment");
1290 SYSCTL_INT(_kern_ipc, OID_AUTO, msgseg, CTLFLAG_RDTUN, &msginfo.msgseg, 0,
1291 "Number of message segments");
1292 SYSCTL_PROC(_kern_ipc, OID_AUTO, msqids, CTLFLAG_RD,
1293 NULL, 0, sysctl_msqids, "", "Message queue IDs");