sys/kern/sys_mqueue.c

   1 /*      $NetBSD: sys_mqueue.c,v 1.16 2009/04/11 23:05:26 christos Exp $ */
   2
   3 /*
   4  * Copyright (c) 2007, 2008 Mindaugas Rasiukevicius <rmind at NetBSD org>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 /*
  30  * Implementation of POSIX message queues.
  31  * Defined in the Base Definitions volume of IEEE Std 1003.1-2001.
  32  *
  33  * Locking
  34  *
  35  * Global list of message queues (mqueue_head) and proc_t::p_mqueue_cnt
  36  * counter are protected by mqlist_mtx lock.  The very message queue and
  37  * its members are protected by mqueue::mq_mtx.
  38  *
  39  * Lock order:
  40  *      mqlist_mtx
  41  *        -> mqueue::mq_mtx
  42  */
  43
  44 #include <sys/param.h>
  45 #include <sys/types.h>
  46 #include <sys/errno.h>
  47 #include <sys/fcntl.h>
  48 #include <sys/file.h>
  49 #include <sys/filedesc.h>
  50 #include <sys/ucred.h>
  51 #include <sys/priv.h>
  52 #include <sys/kernel.h>
  53 #include <sys/malloc.h>
  54 #include <sys/mqueue.h>
  55 #include <sys/proc.h>
  56 #include <sys/queue.h>
  57 #include <sys/event.h>
  58 #include <sys/serialize.h>
  59 #include <sys/signal.h>
  60 #include <sys/signalvar.h>
  61 #include <sys/spinlock.h>
  62 #include <sys/spinlock2.h>
  63 #include <sys/stat.h>
  64 #include <sys/sysctl.h>
  65 #include <sys/sysproto.h>
  66 #include <sys/systm.h>
  67 #include <sys/lock.h>
  68 #include <sys/unistd.h>
  69 #include <sys/vnode.h>
  70
  71 /* System-wide limits. */
  72 static u_int                    mq_open_max = MQ_OPEN_MAX;
  73 static u_int                    mq_prio_max = MQ_PRIO_MAX;
  74 static u_int                    mq_max_msgsize = 16 * MQ_DEF_MSGSIZE;
  75 static u_int                    mq_def_maxmsg = 32;
  76 static u_int                    mq_max_maxmsg = 16 * 32;
  77
  78 struct lock                     mqlist_mtx;
  79 static LIST_HEAD(, mqueue)      mqueue_head =
  80         LIST_HEAD_INITIALIZER(mqueue_head);
  81
  82 typedef struct  file file_t;    /* XXX: Should we put this in sys/types.h ? */
  83
  84 /* Function prototypes */
  85 static int      mq_stat_fop(file_t *, struct stat *, struct ucred *cred);
  86 static int      mq_close_fop(file_t *);
  87 static int      mq_kqfilter_fop(struct file *fp, struct knote *kn);
  88 static void     mqfilter_read_detach(struct knote *kn);
  89 static void     mqfilter_write_detach(struct knote *kn);
  90 static int      mqfilter_read(struct knote *kn, long hint);
  91 static int      mqfilter_write(struct knote *kn, long hint);
  92
  93 /* Some time-related utility functions */
  94 static int      tstohz(const struct timespec *ts);
  95
  96 /* File operations vector */
  97 static struct fileops mqops = {
  98         .fo_read = badfo_readwrite,
  99         .fo_write = badfo_readwrite,
 100         .fo_ioctl = badfo_ioctl,
 101         .fo_stat = mq_stat_fop,
 102         .fo_close = mq_close_fop,
 103         .fo_kqfilter = mq_kqfilter_fop,
 104         .fo_shutdown = badfo_shutdown
 105 };
 106
 107 /* Define a new malloc type for message queues */
 108 MALLOC_DECLARE(M_MQBUF);
 109 MALLOC_DEFINE(M_MQBUF, "mqueues", "Buffers to message queues");
 110
 111 /*
 112  * Initialize POSIX message queue subsystem.
 113  */
 114 void
 115 mqueue_sysinit(void)
 116 {
 117         lockinit(&mqlist_mtx, "mqlist_mtx", 0, LK_CANRECURSE);
 118 }
 119
 120 /*
 121  * Free the message.
 122  */
 123 static void
 124 mqueue_freemsg(struct mq_msg *msg, const size_t size)
 125 {
 126         kfree(msg, M_MQBUF);
 127 }
 128
 129 /*
 130  * Destroy the message queue.
 131  */
 132 static void
 133 mqueue_destroy(struct mqueue *mq)
 134 {
 135         struct mq_msg *msg;
 136         size_t msz;
 137         u_int i;
 138
 139         /* Note MQ_PQSIZE + 1. */
 140         for (i = 0; i < MQ_PQSIZE + 1; i++) {
 141                 while ((msg = TAILQ_FIRST(&mq->mq_head[i])) != NULL) {
 142                         TAILQ_REMOVE(&mq->mq_head[i], msg, msg_queue);
 143                         msz = sizeof(struct mq_msg) + msg->msg_len;
 144                         mqueue_freemsg(msg, msz);
 145                 }
 146         }
 147         lockuninit(&mq->mq_mtx);
 148         kfree(mq, M_MQBUF);
 149 }
 150
 151 /*
 152  * Lookup for file name in general list of message queues.
 153  *  => locks the message queue
 154  */
 155 static void *
 156 mqueue_lookup(char *name)
 157 {
 158         struct mqueue *mq;
 159
 160         KKASSERT(lockstatus(&mqlist_mtx, curthread));
 161
 162         LIST_FOREACH(mq, &mqueue_head, mq_list) {
 163                 if (strncmp(mq->mq_name, name, MQ_NAMELEN) == 0) {
 164                         lockmgr(&mq->mq_mtx, LK_EXCLUSIVE);
 165                         return mq;
 166                 }
 167         }
 168
 169         return NULL;
 170 }
 171
 172 /*
 173  * mqueue_get: get the mqueue from the descriptor.
 174  *  => locks the message queue, if found.
 175  *  => holds a reference on the file descriptor.
 176  */
 177 static int
 178 mqueue_get(struct lwp *l, mqd_t mqd, file_t **fpr)
 179 {
 180         struct mqueue *mq;
 181         file_t *fp;
 182
 183         fp = holdfp(curthread, (int)mqd, -1);   /* XXX: Why -1 ? */
 184         if (__predict_false(fp == NULL))
 185                 return EBADF;
 186
 187         if (__predict_false(fp->f_type != DTYPE_MQUEUE)) {
 188                 fdrop(fp);
 189                 return EBADF;
 190         }
 191         mq = fp->f_data;
 192         lockmgr(&mq->mq_mtx, LK_EXCLUSIVE);
 193
 194         *fpr = fp;
 195         return 0;
 196 }
 197
 198 /*
 199  * mqueue_linear_insert: perform linear insert according to the message
 200  * priority into the reserved queue (MQ_PQRESQ).  Reserved queue is a
 201  * sorted list used only when mq_prio_max is increased via sysctl.
 202  */
 203 static inline void
 204 mqueue_linear_insert(struct mqueue *mq, struct mq_msg *msg)
 205 {
 206         struct mq_msg *mit;
 207
 208         TAILQ_FOREACH(mit, &mq->mq_head[MQ_PQRESQ], msg_queue) {
 209                 if (msg->msg_prio > mit->msg_prio)
 210                         break;
 211         }
 212         if (mit == NULL) {
 213                 TAILQ_INSERT_TAIL(&mq->mq_head[MQ_PQRESQ], msg, msg_queue);
 214         } else {
 215                 TAILQ_INSERT_BEFORE(mit, msg, msg_queue);
 216         }
 217 }
 218
 219 /*
 220  * Compute number of ticks in the specified amount of time.
 221  */
 222 static int
 223 tstohz(const struct timespec *ts)
 224 {
 225         struct timeval tv;
 226
 227         /*
 228          * usec has great enough resolution for hz, so convert to a
 229          * timeval and use tvtohz() above.
 230          */
 231         TIMESPEC_TO_TIMEVAL(&tv, ts);
 232         return tvtohz_high(&tv);        /* XXX Why _high() and not _low() ? */
 233 }
 234
 235 /*
 236  * Converter from struct timespec to the ticks.
 237  * Used by mq_timedreceive(), mq_timedsend().
 238  */
 239 int
 240 abstimeout2timo(struct timespec *ts, int *timo)
 241 {
 242         struct timespec tsd;
 243         int error;
 244
 245         error = itimespecfix(ts);
 246         if (error) {
 247                 return error;
 248         }
 249         getnanotime(&tsd);
 250         timespecsub(ts, &tsd, ts);
 251         if (ts->tv_sec < 0 || (ts->tv_sec == 0 && ts->tv_nsec <= 0)) {
 252                 return ETIMEDOUT;
 253         }
 254         *timo = tstohz(ts);
 255         KKASSERT(*timo != 0);
 256
 257         return 0;
 258 }
 259
 260 static int
 261 mq_stat_fop(file_t *fp, struct stat *st, struct ucred *cred)
 262 {
 263         struct mqueue *mq = fp->f_data;
 264
 265         (void)memset(st, 0, sizeof(*st));
 266
 267         lockmgr(&mq->mq_mtx, LK_EXCLUSIVE);
 268         st->st_mode = mq->mq_mode;
 269         st->st_uid = mq->mq_euid;
 270         st->st_gid = mq->mq_egid;
 271         st->st_atimespec = mq->mq_atime;
 272         st->st_mtimespec = mq->mq_mtime;
 273         /*st->st_ctimespec = st->st_birthtimespec = mq->mq_btime;*/
 274         st->st_uid = fp->f_cred->cr_uid;
 275         st->st_gid = fp->f_cred->cr_svgid;
 276         lockmgr(&mq->mq_mtx, LK_RELEASE);
 277
 278         return 0;
 279 }
 280
 281 static struct filterops mqfiltops_read =
 282 { FILTEROP_ISFD|FILTEROP_MPSAFE, NULL, mqfilter_read_detach, mqfilter_read };
 283 static struct filterops mqfiltops_write =
 284 { FILTEROP_ISFD|FILTEROP_MPSAFE, NULL, mqfilter_write_detach, mqfilter_write };
 285
 286 static int
 287 mq_kqfilter_fop(struct file *fp, struct knote *kn)
 288 {
 289         struct mqueue *mq = fp->f_data;
 290         struct klist *klist;
 291
 292         lockmgr(&mq->mq_mtx, LK_EXCLUSIVE);
 293
 294         switch (kn->kn_filter) {
 295         case EVFILT_READ:
 296                 kn->kn_fop = &mqfiltops_read;
 297                 kn->kn_hook = (caddr_t)mq;
 298                 klist = &mq->mq_rkq.ki_note;
 299                 break;
 300         case EVFILT_WRITE:
 301                 kn->kn_fop = &mqfiltops_write;
 302                 kn->kn_hook = (caddr_t)mq;
 303                 klist = &mq->mq_wkq.ki_note;
 304                 break;
 305         default:
 306                 lockmgr(&mq->mq_mtx, LK_RELEASE);
 307                 return (EOPNOTSUPP);
 308         }
 309
 310         knote_insert(klist, kn);
 311         lockmgr(&mq->mq_mtx, LK_RELEASE);
 312
 313         return (0);
 314 }
 315
 316 static void
 317 mqfilter_read_detach(struct knote *kn)
 318 {
 319         struct mqueue *mq = (struct mqueue *)kn->kn_hook;
 320
 321         lockmgr(&mq->mq_mtx, LK_EXCLUSIVE);
 322         struct klist *klist = &mq->mq_rkq.ki_note;
 323         knote_remove(klist, kn);
 324         lockmgr(&mq->mq_mtx, LK_RELEASE);
 325 }
 326
 327 static void
 328 mqfilter_write_detach(struct knote *kn)
 329 {
 330         struct mqueue *mq = (struct mqueue *)kn->kn_hook;
 331
 332         lockmgr(&mq->mq_mtx, LK_EXCLUSIVE);
 333         struct klist *klist = &mq->mq_wkq.ki_note;
 334         knote_remove(klist, kn);
 335         lockmgr(&mq->mq_mtx, LK_RELEASE);
 336 }
 337
 338 static int
 339 mqfilter_read(struct knote *kn, long hint)
 340 {
 341         struct mqueue *mq = (struct mqueue *)kn->kn_hook;
 342         struct mq_attr *mqattr;
 343         int ready = 0;
 344
 345         lockmgr(&mq->mq_mtx, LK_EXCLUSIVE);
 346         mqattr = &mq->mq_attrib;
 347         /* Ready for receiving, if there are messages in the queue */
 348         if (mqattr->mq_curmsgs)
 349                 ready = 1;
 350         lockmgr(&mq->mq_mtx, LK_RELEASE);
 351
 352         return (ready);
 353 }
 354
 355 static int
 356 mqfilter_write(struct knote *kn, long hint)
 357 {
 358         struct mqueue *mq = (struct mqueue *)kn->kn_hook;
 359         struct mq_attr *mqattr;
 360         int ready = 0;
 361
 362         lockmgr(&mq->mq_mtx, LK_EXCLUSIVE);
 363         mqattr = &mq->mq_attrib;
 364         /* Ready for sending, if the message queue is not full */
 365         if (mqattr->mq_curmsgs < mqattr->mq_maxmsg)
 366                 ready = 1;
 367         lockmgr(&mq->mq_mtx, LK_RELEASE);
 368
 369         return (ready);
 370 }
 371
 372 static int
 373 mq_close_fop(file_t *fp)
 374 {
 375         struct proc *p = curproc;
 376         struct mqueue *mq = fp->f_data;
 377         bool destroy;
 378
 379         lockmgr(&mqlist_mtx, LK_EXCLUSIVE);
 380         lockmgr(&mq->mq_mtx, LK_EXCLUSIVE);
 381
 382         /* Decrease the counters */
 383         p->p_mqueue_cnt--;
 384         mq->mq_refcnt--;
 385
 386         /* Remove notification if registered for this process */
 387         if (mq->mq_notify_proc == p)
 388                 mq->mq_notify_proc = NULL;
 389
 390         /*
 391          * If this is the last reference and mqueue is marked for unlink,
 392          * remove and later destroy the message queue.
 393          */
 394         if (mq->mq_refcnt == 0 && (mq->mq_attrib.mq_flags & MQ_UNLINK)) {
 395                 LIST_REMOVE(mq, mq_list);
 396                 destroy = true;
 397         } else
 398                 destroy = false;
 399
 400         lockmgr(&mq->mq_mtx, LK_RELEASE);
 401         lockmgr(&mqlist_mtx, LK_RELEASE);
 402
 403         if (destroy)
 404                 mqueue_destroy(mq);
 405
 406         return 0;
 407 }
 408
 409 /*
 410  * General mqueue system calls.
 411  */
 412
 413 int
 414 sys_mq_open(struct mq_open_args *uap)
 415 {
 416         /* {
 417                 syscallarg(const char *) name;
 418                 syscallarg(int) oflag;
 419                 syscallarg(mode_t) mode;
 420                 syscallarg(struct mq_attr) attr;
 421         } */
 422         struct thread *td = curthread;
 423         struct proc *p = td->td_proc;
 424         struct filedesc *fdp = p->p_fd;
 425         struct mqueue *mq, *mq_new = NULL;
 426         file_t *fp;
 427         char *name;
 428         int mqd, error, oflag;
 429
 430         /* Check access mode flags */
 431         oflag = SCARG(uap, oflag);
 432         if ((oflag & O_ACCMODE) == (O_WRONLY | O_RDWR)) {
 433                 return EINVAL;
 434         }
 435
 436         /* Get the name from the user-space */
 437         name = kmalloc(MQ_NAMELEN, M_MQBUF, M_WAITOK | M_ZERO | M_NULLOK);
 438         if (name == NULL)
 439                 return (ENOMEM);
 440         error = copyinstr(SCARG(uap, name), name, MQ_NAMELEN - 1, NULL);
 441         if (error) {
 442                 kfree(name, M_MQBUF);
 443                 return error;
 444         }
 445
 446         if (oflag & O_CREAT) {
 447                 struct mq_attr attr;
 448                 u_int i;
 449
 450                 /* Check the limit */
 451                 if (p->p_mqueue_cnt == mq_open_max) {
 452                         kfree(name, M_MQBUF);
 453                         return EMFILE;
 454                 }
 455
 456                 /* Empty name is invalid */
 457                 if (name[0] == '\0') {
 458                         kfree(name, M_MQBUF);
 459                         return EINVAL;
 460                 }
 461
 462                 /* Check for mqueue attributes */
 463                 if (SCARG(uap, attr)) {
 464                         error = copyin(SCARG(uap, attr), &attr,
 465                                 sizeof(struct mq_attr));
 466                         if (error) {
 467                                 kfree(name, M_MQBUF);
 468                                 return error;
 469                         }
 470                         if (attr.mq_maxmsg <= 0 ||
 471                             attr.mq_maxmsg > mq_max_maxmsg ||
 472                             attr.mq_msgsize <= 0 ||
 473                             attr.mq_msgsize > mq_max_msgsize) {
 474                                 kfree(name, M_MQBUF);
 475                                 return EINVAL;
 476                         }
 477                         attr.mq_curmsgs = 0;
 478                 } else {
 479                         memset(&attr, 0, sizeof(struct mq_attr));
 480                         attr.mq_maxmsg = mq_def_maxmsg;
 481                         attr.mq_msgsize =
 482                             MQ_DEF_MSGSIZE - sizeof(struct mq_msg);
 483                 }
 484
 485                 /*
 486                  * Allocate new mqueue, initialize data structures,
 487                  * copy the name, attributes and set the flag.
 488                  */
 489                 mq_new = kmalloc(sizeof(struct mqueue), M_MQBUF,
 490                                         M_WAITOK | M_ZERO | M_NULLOK);
 491                 if (mq_new == NULL) {
 492                         kfree(name, M_MQBUF);
 493                         return (ENOMEM);
 494                 }
 495
 496                 lockinit(&mq_new->mq_mtx, "mq_new->mq_mtx", 0, LK_CANRECURSE);
 497                 for (i = 0; i < (MQ_PQSIZE + 1); i++) {
 498                         TAILQ_INIT(&mq_new->mq_head[i]);
 499                 }
 500
 501                 strlcpy(mq_new->mq_name, name, MQ_NAMELEN);
 502                 memcpy(&mq_new->mq_attrib, &attr, sizeof(struct mq_attr));
 503
 504                 /*CTASSERT((O_MASK & (MQ_UNLINK | MQ_RECEIVE)) == 0);*/
 505                 /* mq_new->mq_attrib.mq_flags = (O_MASK & oflag); */
 506                 mq_new->mq_attrib.mq_flags = oflag;
 507
 508                 /* Store mode and effective UID with GID */
 509                 mq_new->mq_mode = ((SCARG(uap, mode) &
 510                     ~p->p_fd->fd_cmask) & ALLPERMS) & ~S_ISTXT;
 511                 mq_new->mq_euid = td->td_ucred->cr_uid;
 512                 mq_new->mq_egid = td->td_ucred->cr_svgid;
 513         }
 514
 515         /* Allocate file structure and descriptor */
 516         error = falloc(td->td_lwp, &fp, &mqd);
 517         if (error) {
 518                 if (mq_new)
 519                         mqueue_destroy(mq_new);
 520                 kfree(name, M_MQBUF);
 521                 return error;
 522         }
 523         fp->f_type = DTYPE_MQUEUE;
 524         fp->f_flag = FFLAGS(oflag) & (FREAD | FWRITE);
 525         fp->f_ops = &mqops;
 526
 527         /* Look up for mqueue with such name */
 528         lockmgr(&mqlist_mtx, LK_EXCLUSIVE);
 529         mq = mqueue_lookup(name);
 530         if (mq) {
 531                 int acc_mode;
 532
 533                 KKASSERT(lockstatus(&mq->mq_mtx, curthread));
 534
 535                 /* Check if mqueue is not marked as unlinking */
 536                 if (mq->mq_attrib.mq_flags & MQ_UNLINK) {
 537                         error = EACCES;
 538                         goto exit;
 539                 }
 540                 /* Fail if O_EXCL is set, and mqueue already exists */
 541                 if ((oflag & O_CREAT) && (oflag & O_EXCL)) {
 542                         error = EEXIST;
 543                         goto exit;
 544                 }
 545
 546                 /*
 547                  * Check the permissions. Note the difference between
 548                  * VREAD/VWRITE and FREAD/FWRITE.
 549                  */
 550                 acc_mode = 0;
 551                 if (fp->f_flag & FREAD) {
 552                         acc_mode |= VREAD;
 553                 }
 554                 if (fp->f_flag & FWRITE) {
 555                         acc_mode |= VWRITE;
 556                 }
 557                 if (vaccess(VNON, mq->mq_mode, mq->mq_euid, mq->mq_egid,
 558                         acc_mode, td->td_ucred)) {
 559
 560                         error = EACCES;
 561                         goto exit;
 562                 }
 563         } else {
 564                 /* Fail if mqueue neither exists, nor we create it */
 565                 if ((oflag & O_CREAT) == 0) {
 566                         lockmgr(&mqlist_mtx, LK_RELEASE);
 567                         KKASSERT(mq_new == NULL);
 568                         fsetfd(fdp, NULL, mqd);
 569                         fp->f_ops = &badfileops;
 570                         fdrop(fp);
 571                         kfree(name, M_MQBUF);
 572                         return ENOENT;
 573                 }
 574
 575                 /* Check the limit */
 576                 if (p->p_mqueue_cnt == mq_open_max) {
 577                         error = EMFILE;
 578                         goto exit;
 579                 }
 580
 581                 /* Insert the queue to the list */
 582                 mq = mq_new;
 583                 lockmgr(&mq->mq_mtx, LK_EXCLUSIVE);
 584                 LIST_INSERT_HEAD(&mqueue_head, mq, mq_list);
 585                 mq_new = NULL;
 586                 getnanotime(&mq->mq_btime);
 587                 mq->mq_atime = mq->mq_mtime = mq->mq_btime;
 588         }
 589
 590         /* Increase the counters, and make descriptor ready */
 591         p->p_mqueue_cnt++;
 592         mq->mq_refcnt++;
 593         fp->f_data = mq;
 594 exit:
 595         lockmgr(&mq->mq_mtx, LK_RELEASE);
 596         lockmgr(&mqlist_mtx, LK_RELEASE);
 597
 598         if (mq_new)
 599                 mqueue_destroy(mq_new);
 600         if (error) {
 601                 fsetfd(fdp, NULL, mqd);
 602                 fp->f_ops = &badfileops;
 603         } else {
 604                 fsetfd(fdp, fp, mqd);
 605                 uap->sysmsg_result = mqd;
 606         }
 607         fdrop(fp);
 608         kfree(name, M_MQBUF);
 609
 610         return error;
 611 }
 612
 613 int
 614 sys_mq_close(struct mq_close_args *uap)
 615 {
 616         return sys_close((void *)uap);
 617 }
 618
 619 /*
 620  * Primary mq_receive1() function.
 621  */
 622 int
 623 mq_receive1(struct lwp *l, mqd_t mqdes, void *msg_ptr, size_t msg_len,
 624     unsigned *msg_prio, struct timespec *ts, ssize_t *mlen)
 625 {
 626         file_t *fp = NULL;
 627         struct mqueue *mq;
 628         struct mq_msg *msg = NULL;
 629         struct mq_attr *mqattr;
 630         u_int idx;
 631         int error;
 632
 633         /* Get the message queue */
 634         error = mqueue_get(l, mqdes, &fp);
 635         if (error) {
 636                 return error;
 637         }
 638         mq = fp->f_data;
 639         if ((fp->f_flag & FREAD) == 0) {
 640                 error = EBADF;
 641                 goto error;
 642         }
 643         getnanotime(&mq->mq_atime);
 644         mqattr = &mq->mq_attrib;
 645
 646         /* Check the message size limits */
 647         if (msg_len < mqattr->mq_msgsize) {
 648                 error = EMSGSIZE;
 649                 goto error;
 650         }
 651
 652         /* Check if queue is empty */
 653         while (mqattr->mq_curmsgs == 0) {
 654                 int t;
 655
 656                 if (mqattr->mq_flags & O_NONBLOCK) {
 657                         error = EAGAIN;
 658                         goto error;
 659                 }
 660                 if (ts) {
 661                         error = abstimeout2timo(ts, &t);
 662                         if (error)
 663                                 goto error;
 664                 } else
 665                         t = 0;
 666                 /*
 667                  * Block until someone sends the message.
 668                  * While doing this, notification should not be sent.
 669                  */
 670                 mqattr->mq_flags |= MQ_RECEIVE;
 671                 error = lksleep(&mq->mq_send_cv, &mq->mq_mtx, PCATCH, "mqsend", t);
 672                 mqattr->mq_flags &= ~MQ_RECEIVE;
 673                 if (error || (mqattr->mq_flags & MQ_UNLINK)) {
 674                         error = (error == EWOULDBLOCK) ? ETIMEDOUT : EINTR;
 675                         goto error;
 676                 }
 677         }
 678
 679
 680         /*
 681          * Find the highest priority message, and remove it from the queue.
 682          * At first, reserved queue is checked, bitmap is next.
 683          */
 684         msg = TAILQ_FIRST(&mq->mq_head[MQ_PQRESQ]);
 685         if (__predict_true(msg == NULL)) {
 686                 idx = ffs(mq->mq_bitmap);
 687                 msg = TAILQ_FIRST(&mq->mq_head[idx]);
 688                 KKASSERT(msg != NULL);
 689         } else {
 690                 idx = MQ_PQRESQ;
 691         }
 692         TAILQ_REMOVE(&mq->mq_head[idx], msg, msg_queue);
 693
 694         /* Unmark the bit, if last message. */
 695         if (__predict_true(idx) && TAILQ_EMPTY(&mq->mq_head[idx])) {
 696                 KKASSERT((MQ_PQSIZE - idx) == msg->msg_prio);
 697                 mq->mq_bitmap &= ~(1 << --idx);
 698         }
 699
 700         /* Decrement the counter and signal waiter, if any */
 701         mqattr->mq_curmsgs--;
 702         wakeup_one(&mq->mq_recv_cv);
 703
 704         /* Ready for sending now */
 705         KNOTE(&mq->mq_wkq.ki_note, 0);
 706 error:
 707         lockmgr(&mq->mq_mtx, LK_RELEASE);
 708         fdrop(fp);
 709         if (error)
 710                 return error;
 711
 712         /*
 713          * Copy the data to the user-space.
 714          * Note: According to POSIX, no message should be removed from the
 715          * queue in case of fail - this would be violated.
 716          */
 717         *mlen = msg->msg_len;
 718         error = copyout(msg->msg_ptr, msg_ptr, msg->msg_len);
 719         if (error == 0 && msg_prio)
 720                 error = copyout(&msg->msg_prio, msg_prio, sizeof(unsigned));
 721         mqueue_freemsg(msg, sizeof(struct mq_msg) + msg->msg_len);
 722
 723         return error;
 724 }
 725
 726 int
 727 sys_mq_receive(struct mq_receive_args *uap)
 728 {
 729         /* {
 730                 syscallarg(mqd_t) mqdes;
 731                 syscallarg(char *) msg_ptr;
 732                 syscallarg(size_t) msg_len;
 733                 syscallarg(unsigned *) msg_prio;
 734         } */
 735         ssize_t mlen;
 736         int error;
 737
 738         error = mq_receive1(curthread->td_lwp, SCARG(uap, mqdes), SCARG(uap, msg_ptr),
 739             SCARG(uap, msg_len), SCARG(uap, msg_prio), 0, &mlen);
 740         if (error == 0)
 741                 uap->sysmsg_result = mlen;
 742
 743         return error;
 744 }
 745
 746 int
 747 sys_mq_timedreceive(struct mq_timedreceive_args *uap)
 748 {
 749         /* {
 750                 syscallarg(mqd_t) mqdes;
 751                 syscallarg(char *) msg_ptr;
 752                 syscallarg(size_t) msg_len;
 753                 syscallarg(unsigned *) msg_prio;
 754                 syscallarg(const struct timespec *) abs_timeout;
 755         } */
 756         int error;
 757         ssize_t mlen;
 758         struct timespec ts, *tsp;
 759
 760         /* Get and convert time value */
 761         if (SCARG(uap, abs_timeout)) {
 762                 error = copyin(SCARG(uap, abs_timeout), &ts, sizeof(ts));
 763                 if (error)
 764                         return error;
 765                 tsp = &ts;
 766         } else {
 767                 tsp = NULL;
 768         }
 769
 770         error = mq_receive1(curthread->td_lwp, SCARG(uap, mqdes), SCARG(uap, msg_ptr),
 771             SCARG(uap, msg_len), SCARG(uap, msg_prio), tsp, &mlen);
 772         if (error == 0)
 773                 uap->sysmsg_result = mlen;
 774
 775         return error;
 776 }
 777
 778 /*
 779  * Primary mq_send1() function.
 780  */
 781 int
 782 mq_send1(struct lwp *l, mqd_t mqdes, const char *msg_ptr, size_t msg_len,
 783     unsigned msg_prio, struct timespec *ts)
 784 {
 785         file_t *fp = NULL;
 786         struct mqueue *mq;
 787         struct mq_msg *msg;
 788         struct mq_attr *mqattr;
 789         struct proc *notify = NULL;
 790         /*ksiginfo_t ksi;*/
 791         size_t size;
 792         int error;
 793
 794         /* Check the priority range */
 795         if (msg_prio >= mq_prio_max)
 796                 return EINVAL;
 797
 798         /* Allocate a new message */
 799         size = sizeof(struct mq_msg) + msg_len;
 800         if (size > mq_max_msgsize)
 801                 return EMSGSIZE;
 802
 803         msg = kmalloc(size, M_MQBUF, M_WAITOK | M_NULLOK);
 804         if (msg == NULL)
 805                 return (ENOMEM);
 806
 807
 808         /* Get the data from user-space */
 809         error = copyin(msg_ptr, msg->msg_ptr, msg_len);
 810         if (error) {
 811                 mqueue_freemsg(msg, size);
 812                 return error;
 813         }
 814         msg->msg_len = msg_len;
 815         msg->msg_prio = msg_prio;
 816
 817         /* Get the mqueue */
 818         error = mqueue_get(l, mqdes, &fp);
 819         if (error) {
 820                 mqueue_freemsg(msg, size);
 821                 return error;
 822         }
 823         mq = fp->f_data;
 824         if ((fp->f_flag & FWRITE) == 0) {
 825                 error = EBADF;
 826                 goto error;
 827         }
 828         getnanotime(&mq->mq_mtime);
 829         mqattr = &mq->mq_attrib;
 830
 831         /* Check the message size limit */
 832         if (msg_len <= 0 || msg_len > mqattr->mq_msgsize) {
 833                 error = EMSGSIZE;
 834                 goto error;
 835         }
 836
 837         /* Check if queue is full */
 838         while (mqattr->mq_curmsgs >= mqattr->mq_maxmsg) {
 839                 int t;
 840
 841                 if (mqattr->mq_flags & O_NONBLOCK) {
 842                         error = EAGAIN;
 843                         goto error;
 844                 }
 845                 if (ts) {
 846                         error = abstimeout2timo(ts, &t);
 847                         if (error)
 848                                 goto error;
 849                 } else
 850                         t = 0;
 851                 /* Block until queue becomes available */
 852                 error = lksleep(&mq->mq_recv_cv, &mq->mq_mtx, PCATCH, "mqrecv", t);
 853                 if (error || (mqattr->mq_flags & MQ_UNLINK)) {
 854                         error = (error == EWOULDBLOCK) ? ETIMEDOUT : error;
 855                         goto error;
 856                 }
 857         }
 858         KKASSERT(mq->mq_attrib.mq_curmsgs < mq->mq_attrib.mq_maxmsg);
 859
 860         /*
 861          * Insert message into the queue, according to the priority.
 862          * Note the difference between index and priority.
 863          */
 864         if (__predict_true(msg_prio < MQ_PQSIZE)) {
 865                 u_int idx = MQ_PQSIZE - msg_prio;
 866
 867                 KKASSERT(idx != MQ_PQRESQ);
 868                 TAILQ_INSERT_TAIL(&mq->mq_head[idx], msg, msg_queue);
 869                 mq->mq_bitmap |= (1 << --idx);
 870         } else {
 871                 mqueue_linear_insert(mq, msg);
 872         }
 873
 874         /* Check for the notify */
 875         if (mqattr->mq_curmsgs == 0 && mq->mq_notify_proc &&
 876             (mqattr->mq_flags & MQ_RECEIVE) == 0 &&
 877             mq->mq_sig_notify.sigev_notify == SIGEV_SIGNAL) {
 878                 /* Initialize the signal */
 879                 /*KSI_INIT(&ksi);*/
 880                 /*ksi.ksi_signo = mq->mq_sig_notify.sigev_signo;*/
 881                 /*ksi.ksi_code = SI_MESGQ;*/
 882                 /*ksi.ksi_value = mq->mq_sig_notify.sigev_value;*/
 883                 /* Unregister the process */
 884                 notify = mq->mq_notify_proc;
 885                 mq->mq_notify_proc = NULL;
 886         }
 887
 888         /* Increment the counter and signal waiter, if any */
 889         mqattr->mq_curmsgs++;
 890         wakeup_one(&mq->mq_send_cv);
 891
 892         /* Ready for receiving now */
 893         KNOTE(&mq->mq_rkq.ki_note, 0);
 894 error:
 895         if (error) {
 896                 lockmgr(&mq->mq_mtx, LK_RELEASE);
 897                 fdrop(fp);
 898                 mqueue_freemsg(msg, size);
 899         } else if (notify) {
 900                 PHOLD(notify);
 901                 lockmgr(&mq->mq_mtx, LK_RELEASE);
 902                 fdrop(fp);
 903                 /* Send the notify, if needed */
 904                 /*kpsignal(notify, &ksi, NULL);*/
 905                 ksignal(notify, mq->mq_sig_notify.sigev_signo);
 906                 PRELE(notify);
 907         } else {
 908                 lockmgr(&mq->mq_mtx, LK_RELEASE);
 909                 fdrop(fp);
 910         }
 911         return error;
 912 }
 913
 914 int
 915 sys_mq_send(struct mq_send_args *uap)
 916 {
 917         /* {
 918                 syscallarg(mqd_t) mqdes;
 919                 syscallarg(const char *) msg_ptr;
 920                 syscallarg(size_t) msg_len;
 921                 syscallarg(unsigned) msg_prio;
 922         } */
 923
 924         return mq_send1(curthread->td_lwp, SCARG(uap, mqdes), SCARG(uap, msg_ptr),
 925             SCARG(uap, msg_len), SCARG(uap, msg_prio), 0);
 926 }
 927
 928 int
 929 sys_mq_timedsend(struct mq_timedsend_args *uap)
 930 {
 931         /* {
 932                 syscallarg(mqd_t) mqdes;
 933                 syscallarg(const char *) msg_ptr;
 934                 syscallarg(size_t) msg_len;
 935                 syscallarg(unsigned) msg_prio;
 936                 syscallarg(const struct timespec *) abs_timeout;
 937         } */
 938         struct timespec ts, *tsp;
 939         int error;
 940
 941         /* Get and convert time value */
 942         if (SCARG(uap, abs_timeout)) {
 943                 error = copyin(SCARG(uap, abs_timeout), &ts, sizeof(ts));
 944                 if (error)
 945                         return error;
 946                 tsp = &ts;
 947         } else {
 948                 tsp = NULL;
 949         }
 950
 951         return mq_send1(curthread->td_lwp, SCARG(uap, mqdes), SCARG(uap, msg_ptr),
 952             SCARG(uap, msg_len), SCARG(uap, msg_prio), tsp);
 953 }
 954
 955 int
 956 sys_mq_notify(struct mq_notify_args *uap)
 957 {
 958         /* {
 959                 syscallarg(mqd_t) mqdes;
 960                 syscallarg(const struct sigevent *) notification;
 961         } */
 962         file_t *fp = NULL;
 963         struct mqueue *mq;
 964         struct sigevent sig;
 965         int error;
 966
 967         if (SCARG(uap, notification)) {
 968                 /* Get the signal from user-space */
 969                 error = copyin(SCARG(uap, notification), &sig,
 970                     sizeof(struct sigevent));
 971                 if (error)
 972                         return error;
 973                 if (sig.sigev_notify == SIGEV_SIGNAL &&
 974                     (sig.sigev_signo <= 0 || sig.sigev_signo >= NSIG))
 975                         return EINVAL;
 976         }
 977
 978         error = mqueue_get(curthread->td_lwp, SCARG(uap, mqdes), &fp);
 979         if (error)
 980                 return error;
 981         mq = fp->f_data;
 982
 983         if (SCARG(uap, notification)) {
 984                 /* Register notification: set the signal and target process */
 985                 if (mq->mq_notify_proc == NULL) {
 986                         memcpy(&mq->mq_sig_notify, &sig,
 987                             sizeof(struct sigevent));
 988                         mq->mq_notify_proc = curproc;
 989                 } else {
 990                         /* Fail if someone else already registered */
 991                         error = EBUSY;
 992                 }
 993         } else {
 994                 /* Unregister the notification */
 995                 mq->mq_notify_proc = NULL;
 996         }
 997         lockmgr(&mq->mq_mtx, LK_RELEASE);
 998         fdrop(fp);
 999
1000         return error;
1001 }
1002
1003 int
1004 sys_mq_getattr(struct mq_getattr_args *uap)
1005 {
1006         /* {
1007                 syscallarg(mqd_t) mqdes;
1008                 syscallarg(struct mq_attr *) mqstat;
1009         } */
1010         file_t *fp = NULL;
1011         struct mqueue *mq;
1012         struct mq_attr attr;
1013         int error;
1014
1015         /* Get the message queue */
1016         error = mqueue_get(curthread->td_lwp, SCARG(uap, mqdes), &fp);
1017         if (error)
1018                 return error;
1019         mq = fp->f_data;
1020         memcpy(&attr, &mq->mq_attrib, sizeof(struct mq_attr));
1021         lockmgr(&mq->mq_mtx, LK_RELEASE);
1022         fdrop(fp);
1023
1024         return copyout(&attr, SCARG(uap, mqstat), sizeof(struct mq_attr));
1025 }
1026
1027 int
1028 sys_mq_setattr(struct mq_setattr_args *uap)
1029 {
1030         /* {
1031                 syscallarg(mqd_t) mqdes;
1032                 syscallarg(const struct mq_attr *) mqstat;
1033                 syscallarg(struct mq_attr *) omqstat;
1034         } */
1035         file_t *fp = NULL;
1036         struct mqueue *mq;
1037         struct mq_attr attr;
1038         int error, nonblock;
1039
1040         error = copyin(SCARG(uap, mqstat), &attr, sizeof(struct mq_attr));
1041         if (error)
1042                 return error;
1043         nonblock = (attr.mq_flags & O_NONBLOCK);
1044
1045         /* Get the message queue */
1046         error = mqueue_get(curthread->td_lwp, SCARG(uap, mqdes), &fp);
1047         if (error)
1048                 return error;
1049         mq = fp->f_data;
1050
1051         /* Copy the old attributes, if needed */
1052         if (SCARG(uap, omqstat)) {
1053                 memcpy(&attr, &mq->mq_attrib, sizeof(struct mq_attr));
1054         }
1055
1056         /* Ignore everything, except O_NONBLOCK */
1057         if (nonblock)
1058                 mq->mq_attrib.mq_flags |= O_NONBLOCK;
1059         else
1060                 mq->mq_attrib.mq_flags &= ~O_NONBLOCK;
1061
1062         lockmgr(&mq->mq_mtx, LK_RELEASE);
1063         fdrop(fp);
1064
1065         /*
1066          * Copy the data to the user-space.
1067          * Note: According to POSIX, the new attributes should not be set in
1068          * case of fail - this would be violated.
1069          */
1070         if (SCARG(uap, omqstat))
1071                 error = copyout(&attr, SCARG(uap, omqstat),
1072                     sizeof(struct mq_attr));
1073
1074         return error;
1075 }
1076
1077 int
1078 sys_mq_unlink(struct mq_unlink_args *uap)
1079 {
1080         /* {
1081                 syscallarg(const char *) name;
1082         } */
1083         struct thread *td = curthread;
1084         struct mqueue *mq;
1085         char *name;
1086         int error, refcnt = 0;
1087
1088         /* Get the name from the user-space */
1089         name = kmalloc(MQ_NAMELEN, M_MQBUF, M_WAITOK | M_ZERO | M_NULLOK);
1090         if (name == NULL)
1091                 return (ENOMEM);
1092         error = copyinstr(SCARG(uap, name), name, MQ_NAMELEN - 1, NULL);
1093         if (error) {
1094                 kfree(name, M_MQBUF);
1095                 return error;
1096         }
1097
1098         /* Lookup for this file */
1099         lockmgr(&mqlist_mtx, LK_EXCLUSIVE);
1100         mq = mqueue_lookup(name);
1101         if (mq == NULL) {
1102                 error = ENOENT;
1103                 goto error;
1104         }
1105
1106         /* Check the permissions */
1107         if (td->td_ucred->cr_uid != mq->mq_euid &&
1108             priv_check(td, PRIV_ROOT) != 0) {
1109                 lockmgr(&mq->mq_mtx, LK_RELEASE);
1110                 error = EACCES;
1111                 goto error;
1112         }
1113
1114         /* Mark message queue as unlinking, before leaving the window */
1115         mq->mq_attrib.mq_flags |= MQ_UNLINK;
1116
1117         /* Wake up all waiters, if there are such */
1118         wakeup(&mq->mq_send_cv);
1119         wakeup(&mq->mq_recv_cv);
1120
1121         KNOTE(&mq->mq_rkq.ki_note, 0);
1122         KNOTE(&mq->mq_wkq.ki_note, 0);
1123
1124         refcnt = mq->mq_refcnt;
1125         if (refcnt == 0)
1126                 LIST_REMOVE(mq, mq_list);
1127
1128         lockmgr(&mq->mq_mtx, LK_RELEASE);
1129 error:
1130         lockmgr(&mqlist_mtx, LK_RELEASE);
1131
1132         /*
1133          * If there are no references - destroy the message
1134          * queue, otherwise, the last mq_close() will do that.
1135          */
1136         if (error == 0 && refcnt == 0)
1137                 mqueue_destroy(mq);
1138
1139         kfree(name, M_MQBUF);
1140         return error;
1141 }
1142
1143 /*
1144  * SysCtl.
1145  */
1146 SYSCTL_NODE(_kern, OID_AUTO, mqueue,
1147     CTLFLAG_RW, 0, "Message queue options");
1148
1149 SYSCTL_INT(_kern_mqueue, OID_AUTO, mq_open_max,
1150     CTLFLAG_RW, &mq_open_max, 0,
1151     "Maximal number of message queue descriptors per process");
1152
1153 SYSCTL_INT(_kern_mqueue, OID_AUTO, mq_prio_max,
1154     CTLFLAG_RW, &mq_prio_max, 0,
1155     "Maximal priority of the message");
1156
1157 SYSCTL_INT(_kern_mqueue, OID_AUTO, mq_max_msgsize,
1158     CTLFLAG_RW, &mq_max_msgsize, 0,
1159     "Maximal allowed size of the message");
1160
1161 SYSCTL_INT(_kern_mqueue, OID_AUTO, mq_def_maxmsg,
1162     CTLFLAG_RW, &mq_def_maxmsg, 0,
1163     "Default maximal message count");
1164
1165 SYSCTL_INT(_kern_mqueue, OID_AUTO, mq_max_maxmsg,
1166     CTLFLAG_RW, &mq_max_maxmsg, 0,
1167     "Maximal allowed message count");
1168
1169 SYSINIT(sys_mqueue_init, SI_SUB_PRE_DRIVERS, SI_ORDER_ANY, mqueue_sysinit, NULL);