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include/ansidecl.h: import from binutils-gdb
[newlib-cygwin.git] / winsup / cygserver / sysv_msg.cc
blob5051add5aa87fe2ac803d564c3e03ef4fbdc22cb
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 /*
21 * This file is heavily changed to become part of Cygwin's cygserver.
22 */
23
24 #ifdef __OUTSIDE_CYGWIN__
25 #include "woutsup.h"
26 #include <sys/cdefs.h>
27 #ifndef __FBSDID
28 #define __FBSDID(s) const char version[] = (s)
29 #endif
30 __FBSDID("$FreeBSD: /usr/local/www/cvsroot/FreeBSD/src/sys/kern/sysv_msg.c,v 1.52 2003/11/07 04:47:14 rwatson Exp $");
31 /* CV, 2006-01-09: Inspected upstream up to version 1.60. */
32
33 #define _KERNEL 1
34 #define __BSD_VISIBLE 1
35 #include <sys/types.h>
36 #include <sys/sysproto.h>
37 #include <sys/ipc.h>
38 #include <sys/param.h>
39 #include <sys/msg.h>
40 #include <malloc.h>
41 #include <errno.h>
42 #include <time.h>
43 #include "cygserver.h"
44 #include "process.h"
45 #include "cygserver_ipc.h"
46
47 #ifdef __CYGWIN__
48 #define MSG_DEBUG
49 #endif /* __CYGWIN__ */
50
51 #ifdef MSG_DEBUG
52 #define DPRINTF(a) debug a
53 #else
54 #define DPRINTF(a)
55 #endif
56
57 static void msg_freehdr(struct msg *msghdr);
58
59 #ifndef __CYGWIN__
60 int msgctl(struct thread *, struct msgctl_args *);
61 int msgget(struct thread *, struct msgget_args *);
62 int msgsnd(struct thread *, struct msgsnd_args *);
63 int msgrcv(struct thread *, struct msgrcv_args *);
64
65 static sy_call_t *msgcalls[] = {
66 (sy_call_t *)msgctl, (sy_call_t *)msgget,
67 (sy_call_t *)msgsnd, (sy_call_t *)msgrcv
68 };
69 #endif /* __CYGWIN__ */
70
71
72 struct msg {
73 struct msg *msg_next; /* next msg in the chain */
74 long msg_type; /* type of this message */
75 /* >0 -> type of this message */
76 /* 0 -> free header */
77 u_short msg_ts; /* size of this message */
78 short msg_spot; /* location of start of msg in buffer */
79 };
80
81
82 #ifndef MSGSSZ
83 #define MSGSSZ 8 /* Each segment must be 2^N long */
84 #endif
85 #ifndef MSGSEG
86 #define MSGSEG 2048 /* must be less than 32767 */
87 #endif
88 #define MSGMAX (MSGSSZ*MSGSEG)
89 #ifndef MSGMNB
90 #define MSGMNB 2048 /* max # of bytes in a queue */
91 #endif
92 #ifndef MSGMNI
93 #define MSGMNI 40
94 #endif
95 #ifndef MSGTQL
96 #define MSGTQL 40
97 #endif
98
99 /*
100 * Based on the configuration parameters described in an SVR2 (yes, two)
101 * config(1m) man page.
102 *
103 * Each message is broken up and stored in segments that are msgssz bytes
104 * long. For efficiency reasons, this should be a power of two. Also,
105 * it doesn't make sense if it is less than 8 or greater than about 256.
106 * Consequently, msginit in kern/sysv_msg.c checks that msgssz is a power of
107 * two between 8 and 1024 inclusive (and panic's if it isn't).
108 */
109 struct msginfo msginfo = {
110 MSGMAX, /* max chars in a message */
111 MSGMNB, /* max chars in a queue */
112 MSGMNI, /* # of message queue identifiers */
113 MSGTQL, /* max messages in system */
114 MSGSSZ, /* size of a message segment */
115 /* (must be small power of 2 greater than 4) */
116 MSGSEG /* number of message segments */
117 };
118
119 /*
120 * macros to convert between msqid_ds's and msqid's.
121 * (specific to this implementation)
122 */
123 #define MSQID(ix,ds) ((ix) & 0xffff | (((ds).msg_perm.seq << 16) & 0xffff0000))
124 #define MSQID_IX(id) ((id) & 0xffff)
125 #define MSQID_SEQ(id) (((id) >> 16) & 0xffff)
126
127 /*
128 * The rest of this file is specific to this particular implementation.
129 */
130
131 struct msgmap {
132 short next; /* next segment in buffer */
133 /* -1 -> available */
134 /* 0..(MSGSEG-1) -> index of next segment */
135 };
136
137 #define MSG_LOCKED 01000 /* Is this msqid_ds locked? */
138
139 static int nfree_msgmaps; /* # of free map entries */
140 static short free_msgmaps; /* head of linked list of free map entries */
141 static struct msg *free_msghdrs;/* list of free msg headers */
142 static char *msgpool; /* MSGMAX byte long msg buffer pool */
143 static struct msgmap *msgmaps; /* MSGSEG msgmap structures */
144 static struct msg *msghdrs; /* MSGTQL msg headers */
145 static struct msqid_ds *msqids; /* MSGMNI msqid_ds struct's */
146 static struct mtx msq_mtx; /* global mutex for message queues. */
147
148 #ifdef __CYGWIN__
149 static struct msg_info msg_info;
150 #endif /* __CYGWIN__ */
151
152 void
153 msginit()
154 {
155 int i;
156
157 TUNABLE_INT_FETCH("kern.ipc.msgseg", &msginfo.msgseg);
158 TUNABLE_INT_FETCH("kern.ipc.msgssz", &msginfo.msgssz);
159 msginfo.msgmax = msginfo.msgseg * msginfo.msgssz;
160 TUNABLE_INT_FETCH("kern.ipc.msgmnb", &msginfo.msgmnb);
161 TUNABLE_INT_FETCH("kern.ipc.msgmni", &msginfo.msgmni);
162 TUNABLE_INT_FETCH("kern.ipc.msgtql", &msginfo.msgtql);
163
164 msgpool = (char *) sys_malloc(msginfo.msgmax, M_MSG, M_WAITOK);
165 if (msgpool == NULL)
166 panic("msgpool is NULL");
167 msgmaps = (msgmap *) sys_malloc(sizeof(struct msgmap) * msginfo.msgseg, M_MSG, M_WAITOK);
168 if (msgmaps == NULL)
169 panic("msgmaps is NULL");
170 msghdrs = (msg *) sys_malloc(sizeof(struct msg) * msginfo.msgtql, M_MSG, M_WAITOK);
171 if (msghdrs == NULL)
172 panic("msghdrs is NULL");
173 msqids = (msqid_ds *) sys_malloc(sizeof(struct msqid_ds) * msginfo.msgmni, M_MSG, M_WAITOK);
174 if (msqids == NULL)
175 panic("msqids is NULL");
176
177 /*
178 * msginfo.msgssz should be a power of two for efficiency reasons.
179 * It is also pretty silly if msginfo.msgssz is less than 8
180 * or greater than about 256 so ...
181 */
182
183 i = 8;
184 while (i < 1024 && i != msginfo.msgssz)
185 i <<= 1;
186 if (i != msginfo.msgssz) {
187 DPRINTF(("msginfo.msgssz=%d (0x%x)\n", msginfo.msgssz,
188 msginfo.msgssz));
189 panic("msginfo.msgssz not a small power of 2");
190 }
191
192 if (msginfo.msgseg > 32767) {
193 DPRINTF(("msginfo.msgseg=%d\n", msginfo.msgseg));
194 panic("msginfo.msgseg > 32767");
195 }
196
197 if (msgmaps == NULL)
198 panic("msgmaps is NULL");
199
200 for (i = 0; i < msginfo.msgseg; i++) {
201 if (i > 0)
202 msgmaps[i-1].next = i;
203 msgmaps[i].next = -1; /* implies entry is available */
204 }
205 free_msgmaps = 0;
206 nfree_msgmaps = msginfo.msgseg;
207
208 if (msghdrs == NULL)
209 panic("msghdrs is NULL");
210
211 for (i = 0; i < msginfo.msgtql; i++) {
212 msghdrs[i].msg_type = 0;
213 if (i > 0)
214 msghdrs[i-1].msg_next = &msghdrs[i];
215 msghdrs[i].msg_next = NULL;
216 }
217 free_msghdrs = &msghdrs[0];
218
219 if (msqids == NULL)
220 panic("msqids is NULL");
221
222 for (i = 0; i < msginfo.msgmni; i++) {
223 msqids[i].msg_qbytes = 0; /* implies entry is available */
224 msqids[i].msg_perm.seq = 0; /* reset to a known value */
225 msqids[i].msg_perm.mode = 0;
226 }
227 mtx_init(&msq_mtx, "msq", NULL, MTX_DEF);
228 }
229
230 int
231 msgunload()
232 {
233 struct msqid_ds *msqptr;
234 int msqid;
235
236 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
237 /*
238 * Look for an unallocated and unlocked msqid_ds.
239 * msqid_ds's can be locked by msgsnd or msgrcv while
240 * they are copying the message in/out. We can't
241 * re-use the entry until they release it.
242 */
243 msqptr = &msqids[msqid];
244 if (msqptr->msg_qbytes != 0 ||
245 (msqptr->msg_perm.mode & MSG_LOCKED) != 0)
246 break;
247 }
248 #ifndef __CYGWIN__
249 if (msqid != msginfo.msgmni)
250 return (EBUSY);
251 #endif /* __CYGWIN__ */
252
253 sys_free(msgpool, M_MSG);
254 sys_free(msgmaps, M_MSG);
255 sys_free(msghdrs, M_MSG);
256 sys_free(msqids, M_MSG);
257 mtx_destroy(&msq_mtx);
258 return (0);
259 }
260
261
262 #ifndef __CYGWIN__
263 static int
264 sysvmsg_modload(struct module *module, int cmd, void *arg)
265 {
266 int error = 0;
267
268 switch (cmd) {
269 case MOD_LOAD:
270 msginit();
271 break;
272 case MOD_UNLOAD:
273 error = msgunload();
274 break;
275 case MOD_SHUTDOWN:
276 break;
277 default:
278 error = EINVAL;
279 break;
280 }
281 return (error);
282 }
283
284 static moduledata_t sysvmsg_mod = {
285 "sysvmsg",
286 &sysvmsg_modload,
287 NULL
288 };
289
290 SYSCALL_MODULE_HELPER(msgsys);
291 SYSCALL_MODULE_HELPER(msgctl);
292 SYSCALL_MODULE_HELPER(msgget);
293 SYSCALL_MODULE_HELPER(msgsnd);
294 SYSCALL_MODULE_HELPER(msgrcv);
295
296 DECLARE_MODULE(sysvmsg, sysvmsg_mod,
297 SI_SUB_SYSV_MSG, SI_ORDER_FIRST);
298 MODULE_VERSION(sysvmsg, 1);
299
300 /*
301 * Entry point for all MSG calls
302 *
303 * MPSAFE
304 */
305 int
306 msgsys(thread *td, struct msgsys_args *uap)
307 {
308 int error;
309
310 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
311 return (ENOSYS);
312 if (uap->which < 0 ||
313 (unsigned) uap->which >= sizeof(msgcalls)/sizeof(msgcalls[0]))
314 return (EINVAL);
315 error = (*msgcalls[uap->which])(td, &uap->a2);
316 return (error);
317 }
318 #endif
319
320 static void
321 msg_freehdr(struct msg *msghdr)
322 {
323 while (msghdr->msg_ts > 0) {
324 short next;
325 if (msghdr->msg_spot < 0 || msghdr->msg_spot >= msginfo.msgseg)
326 panic("msghdr->msg_spot out of range");
327 next = msgmaps[msghdr->msg_spot].next;
328 msgmaps[msghdr->msg_spot].next = free_msgmaps;
329 free_msgmaps = msghdr->msg_spot;
330 nfree_msgmaps++;
331 msghdr->msg_spot = next;
332 if (msghdr->msg_ts >= msginfo.msgssz)
333 msghdr->msg_ts -= msginfo.msgssz;
334 else
335 msghdr->msg_ts = 0;
336 }
337 if (msghdr->msg_spot != -1)
338 panic("msghdr->msg_spot != -1");
339 msghdr->msg_next = free_msghdrs;
340 free_msghdrs = msghdr;
341 }
342
343 #ifndef _SYS_SYSPROTO_H_
344 struct msgctl_args {
345 int msqid;
346 int cmd;
347 struct msqid_ds *buf;
348 };
349 #endif
350
351 /*
352 * MPSAFE
353 */
354 int
355 msgctl(struct thread *td, struct msgctl_args *uap)
356 {
357 int msqid = uap->msqid;
358 int cmd = uap->cmd;
359 struct msqid_ds *user_msqptr = uap->buf;
360 int rval, error;
361 struct msqid_ds msqbuf;
362 struct msqid_ds *msqptr;
363
364 DPRINTF(("call to msgctl(%d, %d, 0x%x)\n", msqid, cmd, user_msqptr));
365
366 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
367 return (ENOSYS);
368
369 #ifdef __CYGWIN__
370 if (cmd == IPC_INFO) {
371 if (!msqid) {
372 error = copyout(&msginfo, user_msqptr,
373 sizeof(struct msginfo));
374 td->td_retval[0] = error ? -1 : 0;
375 return (error);
376 }
377 if (msqid > msginfo.msgmni)
378 msqid = msginfo.msgmni;
379 error = copyout(msqids, user_msqptr,
380 msqid * sizeof(struct msqid_ds));
381 td->td_retval[0] = error ? -1 : 0;
382 return (error);
383 } else if (cmd == MSG_INFO) {
384 mtx_lock(&msq_mtx);
385 error = copyout(&msg_info, user_msqptr,
386 sizeof(struct msg_info));
387 td->td_retval[0] = error ? -1 : 0;
388 mtx_unlock(&msq_mtx);
389 return (error);
390 }
391 #endif /* __CYGWIN__ */
392 msqid = IPCID_TO_IX(msqid);
393
394 if (msqid < 0 || msqid >= msginfo.msgmni) {
395 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqid,
396 msginfo.msgmni));
397 return (EINVAL);
398 }
399 if (cmd == IPC_SET &&
400 (error = copyin(user_msqptr, &msqbuf, sizeof(msqbuf))) != 0)
401 return (error);
402
403 msqptr = &msqids[msqid];
404
405 mtx_lock(&msq_mtx);
406 if (msqptr->msg_qbytes == 0) {
407 DPRINTF(("no such msqid\n"));
408 error = EINVAL;
409 goto done2;
410 }
411 if (msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
412 DPRINTF(("wrong sequence number\n"));
413 error = EINVAL;
414 goto done2;
415 }
416
417 error = 0;
418 rval = 0;
419
420 switch (cmd) {
421
422 case IPC_RMID:
423 {
424 struct msg *msghdr;
425 if ((error = ipcperm(td, &msqptr->msg_perm, IPC_M)))
426 goto done2;
427 /* Free the message headers */
428 msghdr = msqptr->msg_first;
429 while (msghdr != NULL) {
430 struct msg *msghdr_tmp;
431
432 /* Free the segments of each message */
433 msqptr->msg_cbytes -= msghdr->msg_ts;
434 msqptr->msg_qnum--;
435 msghdr_tmp = msghdr;
436 msghdr = msghdr->msg_next;
437 msg_freehdr(msghdr_tmp);
438 }
439
440 if (msqptr->msg_cbytes != 0)
441 panic("msg_cbytes is screwed up");
442 if (msqptr->msg_qnum != 0)
443 panic("msg_qnum is screwed up");
444
445 msqptr->msg_qbytes = 0; /* Mark it as free */
446 #ifdef __CYGWIN__
447 msg_info.msg_ids--;
448 #endif /* __CYGWIN__ */
449
450 wakeup(msqptr);
451 }
452
453 break;
454
455 case IPC_SET:
456 if ((error = ipcperm(td, &msqptr->msg_perm, IPC_M)))
457 goto done2;
458 if (msqbuf.msg_qbytes > msqptr->msg_qbytes) {
459 error = suser(td);
460 if (error)
461 goto done2;
462 }
463 if (msqbuf.msg_qbytes > (unsigned long) msginfo.msgmnb) {
464 DPRINTF(("can't increase msg_qbytes beyond %d"
465 "(truncating)\n", msginfo.msgmnb));
466 msqbuf.msg_qbytes = msginfo.msgmnb; /* silently restrict qbytes to system limit */
467 }
468 if (msqbuf.msg_qbytes == 0) {
469 DPRINTF(("can't reduce msg_qbytes to 0\n"));
470 error = EINVAL; /* non-standard errno! */
471 goto done2;
472 }
473 msqptr->msg_perm.uid = msqbuf.msg_perm.uid; /* change the owner */
474 msqptr->msg_perm.gid = msqbuf.msg_perm.gid; /* change the owner */
475 msqptr->msg_perm.mode = (msqptr->msg_perm.mode & ~0777) |
476 (msqbuf.msg_perm.mode & 0777);
477 msqptr->msg_qbytes = msqbuf.msg_qbytes;
478 msqptr->msg_ctime = time (NULL);
479 break;
480
481 case IPC_STAT:
482 if ((error = ipcperm(td, &msqptr->msg_perm, IPC_R))) {
483 DPRINTF(("requester doesn't have read access\n"));
484 goto done2;
485 }
486 break;
487
488 default:
489 DPRINTF(("invalid command %d\n", cmd));
490 error = EINVAL;
491 goto done2;
492 }
493
494 if (error == 0)
495 td->td_retval[0] = rval;
496 done2:
497 mtx_unlock(&msq_mtx);
498 if (cmd == IPC_STAT && error == 0)
499 error = copyout(msqptr, user_msqptr, sizeof(struct msqid_ds));
500 return(error);
501 }
502
503 #ifndef _SYS_SYSPROTO_H_
504 struct msgget_args {
505 key_t key;
506 int msgflg;
507 };
508 #endif
509
510 /*
511 * MPSAFE
512 */
513 int
514 msgget(struct thread *td, struct msgget_args *uap)
515 {
516 int msqid, error = 0;
517 key_t key = uap->key;
518 unsigned msgflg = uap->msgflg;
519 struct msqid_ds *msqptr = NULL;
520
521 DPRINTF(("msgget(0x%x, 0%o)\n", key, msgflg));
522
523 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
524 return (ENOSYS);
525
526 mtx_lock(&msq_mtx);
527 if (key != IPC_PRIVATE) {
528 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
529 msqptr = &msqids[msqid];
530 if (msqptr->msg_qbytes != 0 &&
531 msqptr->msg_perm.key == key)
532 break;
533 }
534 if (msqid < msginfo.msgmni) {
535 DPRINTF(("found public key\n"));
536 if ((msgflg & IPC_CREAT) && (msgflg & IPC_EXCL)) {
537 DPRINTF(("not exclusive\n"));
538 error = EEXIST;
539 goto done2;
540 }
541 if ((error = ipcperm(td, &msqptr->msg_perm, msgflg & 0700))) {
542 DPRINTF(("requester doesn't have 0%o access\n",
543 msgflg & 0700));
544 goto done2;
545 }
546 goto found;
547 }
548 }
549
550 DPRINTF(("need to allocate the msqid_ds\n"));
551 if (key == IPC_PRIVATE || (msgflg & IPC_CREAT)) {
552 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
553 /*
554 * Look for an unallocated and unlocked msqid_ds.
555 * msqid_ds's can be locked by msgsnd or msgrcv while
556 * they are copying the message in/out. We can't
557 * re-use the entry until they release it.
558 */
559 msqptr = &msqids[msqid];
560 if (msqptr->msg_qbytes == 0 &&
561 (msqptr->msg_perm.mode & MSG_LOCKED) == 0)
562 break;
563 }
564 if (msqid == msginfo.msgmni) {
565 DPRINTF(("no more msqid_ds's available\n"));
566 error = ENOSPC;
567 goto done2;
568 }
569 DPRINTF(("msqid %d is available\n", msqid));
570 msqptr->msg_perm.key = key;
571 #ifdef __CYGWIN__
572 msqptr->msg_perm.cuid = td->ipcblk->uid;
573 msqptr->msg_perm.uid = td->ipcblk->uid;
574 msqptr->msg_perm.cgid = td->ipcblk->gid;
575 msqptr->msg_perm.gid = td->ipcblk->gid;
576 #else
577 msqptr->msg_perm.cuid = cred->cr_uid;
578 msqptr->msg_perm.uid = cred->cr_uid;
579 msqptr->msg_perm.cgid = cred->cr_gid;
580 msqptr->msg_perm.gid = cred->cr_gid;
581 #endif /* __CYGWIN__ */
582 msqptr->msg_perm.mode = (msgflg & 0777);
583 /* Make sure that the returned msqid is unique */
584 msqptr->msg_perm.seq = (msqptr->msg_perm.seq + 1) & 0x7fff;
585 msqptr->msg_first = NULL;
586 msqptr->msg_last = NULL;
587 msqptr->msg_cbytes = 0;
588 msqptr->msg_qnum = 0;
589 msqptr->msg_qbytes = msginfo.msgmnb;
590 msqptr->msg_lspid = 0;
591 msqptr->msg_lrpid = 0;
592 msqptr->msg_stime = 0;
593 msqptr->msg_rtime = 0;
594 msqptr->msg_ctime = time (NULL);
595 #ifdef __CYGWIN__
596 msg_info.msg_ids++;
597 #endif /* __CYGWIN__ */
598 } else {
599 DPRINTF(("didn't find it and wasn't asked to create it\n"));
600 error = ENOENT;
601 goto done2;
602 }
603
604 found:
605 /* Construct the unique msqid */
606 td->td_retval[0] = IXSEQ_TO_IPCID(msqid, msqptr->msg_perm);
607 done2:
608 mtx_unlock(&msq_mtx);
609 return (error);
610 }
611
612 #ifndef _SYS_SYSPROTO_H_
613 struct msgsnd_args {
614 int msqid;
615 const void *msgp;
616 size_t msgsz;
617 int msgflg;
618 };
619 #endif
620
621 /*
622 * MPSAFE
623 */
624 int
625 msgsnd(struct thread *td, struct msgsnd_args *uap)
626 {
627 int msqid = uap->msqid;
628 const void *user_msgp = uap->msgp;
629 size_t msgsz = uap->msgsz;
630 int msgflg = uap->msgflg;
631 int segs_needed, error = 0;
632 struct msqid_ds *msqptr;
633 struct msg *msghdr;
634 short next;
635
636 DPRINTF(("call to msgsnd(%d, 0x%x, %d, %d)\n", msqid, user_msgp, msgsz,
637 msgflg));
638
639 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
640 return (ENOSYS);
641
642 mtx_lock(&msq_mtx);
643 msqid = IPCID_TO_IX(msqid);
644
645 if (msqid < 0 || msqid >= msginfo.msgmni) {
646 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqid,
647 msginfo.msgmni));
648 error = EINVAL;
649 goto done2;
650 }
651
652 msqptr = &msqids[msqid];
653 if (msqptr->msg_qbytes == 0) {
654 DPRINTF(("no such message queue id\n"));
655 error = EINVAL;
656 goto done2;
657 }
658 if (msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
659 DPRINTF(("wrong sequence number\n"));
660 error = EINVAL;
661 goto done2;
662 }
663
664 if ((error = ipcperm(td, &msqptr->msg_perm, IPC_W))) {
665 DPRINTF(("requester doesn't have write access\n"));
666 goto done2;
667 }
668
669 segs_needed = (msgsz + msginfo.msgssz - 1) / msginfo.msgssz;
670 DPRINTF(("msgsz=%d, msgssz=%d, segs_needed=%d\n", msgsz, msginfo.msgssz,
671 segs_needed));
672 for (;;) {
673 int need_more_resources = 0;
674
675 /*
676 * check msgsz
677 * (inside this loop in case msg_qbytes changes while we sleep)
678 */
679
680 if (msgsz > msqptr->msg_qbytes) {
681 DPRINTF(("msgsz > msqptr->msg_qbytes\n"));
682 error = EINVAL;
683 goto done2;
684 }
685
686 if (msqptr->msg_perm.mode & MSG_LOCKED) {
687 DPRINTF(("msqid is locked\n"));
688 need_more_resources = 1;
689 }
690 if (msgsz + msqptr->msg_cbytes > msqptr->msg_qbytes) {
691 DPRINTF(("msgsz + msg_cbytes > msg_qbytes\n"));
692 need_more_resources = 1;
693 }
694 if (segs_needed > nfree_msgmaps) {
695 DPRINTF(("segs_needed > nfree_msgmaps\n"));
696 need_more_resources = 1;
697 }
698 if (free_msghdrs == NULL) {
699 DPRINTF(("no more msghdrs\n"));
700 need_more_resources = 1;
701 }
702
703 if (need_more_resources) {
704 int we_own_it;
705
706 if ((msgflg & IPC_NOWAIT) != 0) {
707 DPRINTF(("need more resources but caller "
708 "doesn't want to wait\n"));
709 error = EAGAIN;
710 goto done2;
711 }
712
713 if ((msqptr->msg_perm.mode & MSG_LOCKED) != 0) {
714 DPRINTF(("we don't own the msqid_ds\n"));
715 we_own_it = 0;
716 } else {
717 /* Force later arrivals to wait for our
718 request */
719 DPRINTF(("we own the msqid_ds\n"));
720 msqptr->msg_perm.mode |= MSG_LOCKED;
721 we_own_it = 1;
722 }
723 DPRINTF(("goodnight\n"));
724 error = msleep(msqptr, &msq_mtx, (PZERO - 4) | PCATCH,
725 "msgsnd", 50);
726 DPRINTF(("good morning, error=%d\n", error));
727 if (we_own_it)
728 msqptr->msg_perm.mode &= ~MSG_LOCKED;
729 if (error == EWOULDBLOCK) {
730 DPRINTF(("timed out\n"));
731 continue;
732 }
733 if (error != 0) {
734 DPRINTF(("msgsnd: interrupted system call\n"));
735 #ifdef __CYGWIN__
736 if (error == EIDRM)
737 goto done2;
738 #endif /* __CYGWIN__ */
739 error = EINTR;
740 goto done2;
741 }
742
743 /*
744 * Make sure that the msq queue still exists
745 */
746
747 if (msqptr->msg_qbytes == 0) {
748 DPRINTF(("msqid deleted\n"));
749 error = EIDRM;
750 goto done2;
751 }
752
753 } else {
754 DPRINTF(("got all the resources that we need\n"));
755 break;
756 }
757 }
758
759 /*
760 * We have the resources that we need.
761 * Make sure!
762 */
763
764 if (msqptr->msg_perm.mode & MSG_LOCKED)
765 panic("msg_perm.mode & MSG_LOCKED");
766 if (segs_needed > nfree_msgmaps)
767 panic("segs_needed > nfree_msgmaps");
768 if (msgsz + msqptr->msg_cbytes > msqptr->msg_qbytes)
769 panic("msgsz + msg_cbytes > msg_qbytes");
770 if (free_msghdrs == NULL)
771 panic("no more msghdrs");
772
773 /*
774 * Re-lock the msqid_ds in case we page-fault when copying in the
775 * message
776 */
777
778 if ((msqptr->msg_perm.mode & MSG_LOCKED) != 0)
779 panic("msqid_ds is already locked");
780 msqptr->msg_perm.mode |= MSG_LOCKED;
781
782 /*
783 * Allocate a message header
784 */
785
786 msghdr = free_msghdrs;
787 free_msghdrs = msghdr->msg_next;
788 msghdr->msg_spot = -1;
789 msghdr->msg_ts = msgsz;
790
791 /*
792 * Allocate space for the message
793 */
794
795 while (segs_needed > 0) {
796 if (nfree_msgmaps <= 0)
797 panic("not enough msgmaps");
798 if (free_msgmaps == -1)
799 panic("nil free_msgmaps");
800 next = free_msgmaps;
801 if (next <= -1)
802 panic("next too low #1");
803 if (next >= msginfo.msgseg)
804 panic("next out of range #1");
805 DPRINTF(("allocating segment %d to message\n", next));
806 free_msgmaps = msgmaps[next].next;
807 nfree_msgmaps--;
808 msgmaps[next].next = msghdr->msg_spot;
809 msghdr->msg_spot = next;
810 segs_needed--;
811 }
812
813 /*
814 * Copy in the message type
815 */
816
817 mtx_unlock(&msq_mtx);
818 if ((error = copyin(user_msgp, &msghdr->msg_type,
819 sizeof(msghdr->msg_type))) != 0) {
820 mtx_lock(&msq_mtx);
821 DPRINTF(("error %d copying the message type\n", error));
822 msg_freehdr(msghdr);
823 msqptr->msg_perm.mode &= ~MSG_LOCKED;
824 wakeup(msqptr);
825 goto done2;
826 }
827 mtx_lock(&msq_mtx);
828 user_msgp = (const char *)user_msgp + sizeof(msghdr->msg_type);
829
830 /*
831 * Validate the message type
832 */
833
834 if (msghdr->msg_type < 1) {
835 msg_freehdr(msghdr);
836 msqptr->msg_perm.mode &= ~MSG_LOCKED;
837 wakeup(msqptr);
838 DPRINTF(("mtype (%d) < 1\n", msghdr->msg_type));
839 error = EINVAL;
840 goto done2;
841 }
842
843 /*
844 * Copy in the message body
845 */
846
847 next = msghdr->msg_spot;
848 while (msgsz > 0) {
849 size_t tlen;
850 if (msgsz > (unsigned long) msginfo.msgssz)
851 tlen = msginfo.msgssz;
852 else
853 tlen = msgsz;
854 if (next <= -1)
855 panic("next too low #2");
856 if (next >= msginfo.msgseg)
857 panic("next out of range #2");
858 mtx_unlock(&msq_mtx);
859 if ((error = copyin(user_msgp, &msgpool[next * msginfo.msgssz],
860 tlen)) != 0) {
861 mtx_lock(&msq_mtx);
862 DPRINTF(("error %d copying in message segment\n",
863 error));
864 msg_freehdr(msghdr);
865 msqptr->msg_perm.mode &= ~MSG_LOCKED;
866 wakeup(msqptr);
867 goto done2;
868 }
869 mtx_lock(&msq_mtx);
870 msgsz -= tlen;
871 user_msgp = (const char *)user_msgp + tlen;
872 next = msgmaps[next].next;
873 }
874 if (next != -1)
875 panic("didn't use all the msg segments");
876
877 /*
878 * We've got the message. Unlock the msqid_ds.
879 */
880
881 msqptr->msg_perm.mode &= ~MSG_LOCKED;
882
883 /*
884 * Make sure that the msqid_ds is still allocated.
885 */
886
887 if (msqptr->msg_qbytes == 0) {
888 msg_freehdr(msghdr);
889 wakeup(msqptr);
890 error = EIDRM;
891 goto done2;
892 }
893
894 /*
895 * Put the message into the queue
896 */
897
898 if (msqptr->msg_first == NULL) {
899 msqptr->msg_first = msghdr;
900 msqptr->msg_last = msghdr;
901 } else {
902 msqptr->msg_last->msg_next = msghdr;
903 msqptr->msg_last = msghdr;
904 }
905 msqptr->msg_last->msg_next = NULL;
906
907 msqptr->msg_cbytes += msghdr->msg_ts;
908 msqptr->msg_qnum++;
909 msqptr->msg_lspid = td->td_proc->p_pid;
910 msqptr->msg_stime = time (NULL);
911
912 #ifdef __CYGWIN__
913 msg_info.msg_num++;
914 msg_info.msg_tot += uap->msgsz;
915 #endif /* __CYGWIN__ */
916
917 wakeup(msqptr);
918 td->td_retval[0] = 0;
919 done2:
920 mtx_unlock(&msq_mtx);
921 return (error);
922 }
923
924 #ifndef _SYS_SYSPROTO_H_
925 struct msgrcv_args {
926 int msqid;
927 void *msgp;
928 size_t msgsz;
929 long msgtyp;
930 int msgflg;
931 };
932 #endif
933
934 /*
935 * MPSAFE
936 */
937 int
938 msgrcv(struct thread *td, struct msgrcv_args *uap)
939 {
940 int msqid = uap->msqid;
941 void *user_msgp = uap->msgp;
942 size_t msgsz = uap->msgsz;
943 long msgtyp = uap->msgtyp;
944 int msgflg = uap->msgflg;
945 size_t len;
946 struct msqid_ds *msqptr;
947 struct msg *msghdr;
948 int error = 0;
949 short next;
950
951 DPRINTF(("call to msgrcv(%d, 0x%x, %d, %ld, %d)\n", msqid, user_msgp,
952 msgsz, msgtyp, msgflg));
953
954 if (!jail_sysvipc_allowed && jailed(td->td_ucred))
955 return (ENOSYS);
956
957 msqid = IPCID_TO_IX(msqid);
958
959 if (msqid < 0 || msqid >= msginfo.msgmni) {
960 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqid,
961 msginfo.msgmni));
962 return (EINVAL);
963 }
964
965 msqptr = &msqids[msqid];
966 mtx_lock(&msq_mtx);
967 if (msqptr->msg_qbytes == 0) {
968 DPRINTF(("no such message queue id\n"));
969 error = EINVAL;
970 goto done2;
971 }
972 if (msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
973 DPRINTF(("wrong sequence number\n"));
974 error = EINVAL;
975 goto done2;
976 }
977
978 if ((error = ipcperm(td, &msqptr->msg_perm, IPC_R))) {
979 DPRINTF(("requester doesn't have read access\n"));
980 goto done2;
981 }
982
983 msghdr = NULL;
984 while (msghdr == NULL) {
985 if (msgtyp == 0) {
986 msghdr = msqptr->msg_first;
987 if (msghdr != NULL) {
988 if (msgsz < msghdr->msg_ts &&
989 (msgflg & MSG_NOERROR) == 0) {
990 DPRINTF(("first message on the queue "
991 "is too big (want %d, got %d)\n",
992 msgsz, msghdr->msg_ts));
993 error = E2BIG;
994 goto done2;
995 }
996 if (msqptr->msg_first == msqptr->msg_last) {
997 msqptr->msg_first = NULL;
998 msqptr->msg_last = NULL;
999 } else {
1000 msqptr->msg_first = msghdr->msg_next;
1001 if (msqptr->msg_first == NULL)
1002 panic("msg_first/last screwed up #1");
1003 }
1004 }
1005 } else {
1006 struct msg *previous;
1007 struct msg **prev;
1008
1009 previous = NULL;
1010 prev = &(msqptr->msg_first);
1011 while ((msghdr = *prev) != NULL) {
1012 /*
1013 * Is this message's type an exact match or is
1014 * this message's type less than or equal to
1015 * the absolute value of a negative msgtyp?
1016 * Note that the second half of this test can
1017 * NEVER be true if msgtyp is positive since
1018 * msg_type is always positive!
1019 */
1020
1021 if (msgtyp == msghdr->msg_type ||
1022 msghdr->msg_type <= -msgtyp) {
1023 DPRINTF(("found message type %d, "
1024 "requested %d\n",
1025 msghdr->msg_type, msgtyp));
1026 if (msgsz < msghdr->msg_ts &&
1027 (msgflg & MSG_NOERROR) == 0) {
1028 DPRINTF(("requested message "
1029 "on the queue is too big "
1030 "(want %d, got %d)\n",
1031 msgsz, msghdr->msg_ts));
1032 error = E2BIG;
1033 goto done2;
1034 }
1035 *prev = msghdr->msg_next;
1036 if (msghdr == msqptr->msg_last) {
1037 if (previous == NULL) {
1038 if (prev !=
1039 &msqptr->msg_first)
1040 panic("msg_first/last screwed up #2");
1041 msqptr->msg_first =
1042 NULL;
1043 msqptr->msg_last =
1044 NULL;
1045 } else {
1046 if (prev ==
1047 &msqptr->msg_first)
1048 panic("msg_first/last screwed up #3");
1049 msqptr->msg_last =
1050 previous;
1051 }
1052 }
1053 break;
1054 }
1055 previous = msghdr;
1056 prev = &(msghdr->msg_next);
1057 }
1058 }
1059
1060 /*
1061 * We've either extracted the msghdr for the appropriate
1062 * message or there isn't one.
1063 * If there is one then bail out of this loop.
1064 */
1065
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 DPRINTF(("no appropriate message found (msgtyp=%d)\n",
1075 msgtyp));
1076 /* The SVID says to return ENOMSG. */
1077 error = ENOMSG;
1078 goto done2;
1079 }
1080
1081 /*
1082 * Wait for something to happen
1083 */
1084
1085 DPRINTF(("msgrcv: goodnight\n"));
1086 error = msleep(msqptr, &msq_mtx, (PZERO - 4) | PCATCH,
1087 "msgrcv", 0);
1088 DPRINTF(("msgrcv: good morning (error=%d)\n", error));
1089
1090 if (error != 0) {
1091 DPRINTF(("msgrcv: interrupted system call\n"));
1092 #ifdef __CYGWIN__
1093 if (error == EIDRM)
1094 goto done2;
1095 #endif /* __CYGWIN__ */
1096 error = EINTR;
1097 goto done2;
1098 }
1099
1100 /*
1101 * Make sure that the msq queue still exists
1102 */
1103
1104 if (msqptr->msg_qbytes == 0 ||
1105 msqptr->msg_perm.seq != IPCID_TO_SEQ(uap->msqid)) {
1106 DPRINTF(("msqid deleted\n"));
1107 error = EIDRM;
1108 goto done2;
1109 }
1110 }
1111
1112 /*
1113 * Return the message to the user.
1114 *
1115 * First, do the bookkeeping (before we risk being interrupted).
1116 */
1117
1118 msqptr->msg_cbytes -= msghdr->msg_ts;
1119 msqptr->msg_qnum--;
1120 msqptr->msg_lrpid = td->td_proc->p_pid;
1121 msqptr->msg_rtime = time (NULL);
1122
1123 /*
1124 * Make msgsz the actual amount that we'll be returning.
1125 * Note that this effectively truncates the message if it is too long
1126 * (since msgsz is never increased).
1127 */
1128
1129 DPRINTF(("found a message, msgsz=%d, msg_ts=%d\n", msgsz,
1130 msghdr->msg_ts));
1131 if (msgsz > msghdr->msg_ts)
1132 msgsz = msghdr->msg_ts;
1133
1134 /*
1135 * Return the type to the user.
1136 */
1137
1138 mtx_unlock(&msq_mtx);
1139 error = copyout(&(msghdr->msg_type), user_msgp,
1140 sizeof(msghdr->msg_type));
1141 mtx_lock(&msq_mtx);
1142 if (error != 0) {
1143 DPRINTF(("error (%d) copying out message type\n", error));
1144 msg_freehdr(msghdr);
1145 wakeup(msqptr);
1146 goto done2;
1147 }
1148 user_msgp = (char *)user_msgp + sizeof(msghdr->msg_type);
1149
1150 /*
1151 * Return the segments to the user
1152 */
1153
1154 next = msghdr->msg_spot;
1155 for (len = 0; len < msgsz; len += msginfo.msgssz) {
1156 size_t tlen;
1157
1158 if (msgsz - len > (unsigned long) msginfo.msgssz)
1159 tlen = msginfo.msgssz;
1160 else
1161 tlen = msgsz - len;
1162 if (next <= -1)
1163 panic("next too low #3");
1164 if (next >= msginfo.msgseg)
1165 panic("next out of range #3");
1166 mtx_unlock(&msq_mtx);
1167 error = copyout(&msgpool[next * msginfo.msgssz],
1168 user_msgp, tlen);
1169 mtx_lock(&msq_mtx);
1170 if (error != 0) {
1171 DPRINTF(("error (%d) copying out message segment\n",
1172 error));
1173 msg_freehdr(msghdr);
1174 wakeup(msqptr);
1175 goto done2;
1176 }
1177 user_msgp = (char *)user_msgp + tlen;
1178 next = msgmaps[next].next;
1179 }
1180
1181 /*
1182 * Done, return the actual number of bytes copied out.
1183 */
1184
1185 #ifdef __CYGWIN__
1186 msg_info.msg_num--;
1187 msg_info.msg_tot -= msgsz;
1188 #endif /* __CYGWIN__ */
1189
1190 msg_freehdr(msghdr);
1191 wakeup(msqptr);
1192 td->td_retval[0] = msgsz;
1193 done2:
1194 mtx_unlock(&msq_mtx);
1195 return (error);
1196 }
1197
1198 #ifndef __CYGWIN__
1199 static int
1200 sysctl_msqids(SYSCTL_HANDLER_ARGS)
1201 {
1202
1203 return (SYSCTL_OUT(req, msqids,
1204 sizeof(struct msqid_ds) * msginfo.msgmni));
1205 }
1206
1207 SYSCTL_DECL(_kern_ipc);
1208 SYSCTL_INT(_kern_ipc, OID_AUTO, msgmax, CTLFLAG_RD, &msginfo.msgmax, 0, "");
1209 SYSCTL_INT(_kern_ipc, OID_AUTO, msgmni, CTLFLAG_RDTUN, &msginfo.msgmni, 0, "");
1210 SYSCTL_INT(_kern_ipc, OID_AUTO, msgmnb, CTLFLAG_RD, &msginfo.msgmnb, 0, "");
1211 SYSCTL_INT(_kern_ipc, OID_AUTO, msgtql, CTLFLAG_RD, &msginfo.msgtql, 0, "");
1212 SYSCTL_INT(_kern_ipc, OID_AUTO, msgssz, CTLFLAG_RDTUN, &msginfo.msgssz, 0, "");
1213 SYSCTL_INT(_kern_ipc, OID_AUTO, msgseg, CTLFLAG_RDTUN, &msginfo.msgseg, 0, "");
1214 SYSCTL_PROC(_kern_ipc, OID_AUTO, msqids, CTLFLAG_RD,
1215 NULL, 0, sysctl_msqids, "", "Message queue IDs");
1216 #endif /* __CYGWIN__ */
1217 #endif /* __OUTSIDE_CYGWIN__ */