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 <stdbool.h>
  45 #include <sys/param.h>
  46 #include <sys/types.h>
  47 #include <sys/errno.h>
  48 #include <sys/fcntl.h>
  49 #include <sys/file.h>
  50 #include <sys/filedesc.h>
  51 #include <sys/ucred.h>
  52 #include <sys/priv.h>
  53 #include <sys/kernel.h>
  54 #include <sys/malloc.h>
  55 #include <sys/mqueue.h>
  56 #include <sys/objcache.h>
  57 #include <sys/poll.h>
  58 #include <sys/proc.h>
  59 #include <sys/queue.h>
  60 #include <sys/select.h>
  61 #include <sys/serialize.h>
  62 #include <sys/signal.h>
  63 #include <sys/signalvar.h>
  64 #include <sys/spinlock.h>
  65 #include <sys/spinlock2.h>
  66 #include <sys/stat.h>
  67 #include <sys/sysctl.h>
  68 #include <sys/sysproto.h>
  69 #include <sys/systm.h>
  70 #include <sys/lock.h>
  71 #include <sys/unistd.h>
  72 #include <sys/vnode.h>
  73
  74 /* System-wide limits. */
  75 static u_int                    mq_open_max = MQ_OPEN_MAX;
  76 static u_int                    mq_prio_max = MQ_PRIO_MAX;
  77 static u_int                    mq_max_msgsize = 16 * MQ_DEF_MSGSIZE;
  78 static u_int                    mq_def_maxmsg = 32;
  79
  80 struct lock                     mqlist_mtx;
  81 static struct objcache *        mqmsg_cache;
  82 static LIST_HEAD(, mqueue)      mqueue_head =
  83         LIST_HEAD_INITIALIZER(mqueue_head);
  84
  85 typedef struct  file file_t;    /* XXX: Should we put this in sys/types.h ? */
  86
  87 /* Function prototypes */
  88 static int      mq_poll_fop(file_t *, int, struct ucred *cred);
  89 static int      mq_stat_fop(file_t *, struct stat *, struct ucred *cred);
  90 static int      mq_close_fop(file_t *);
  91
  92 /* Some time-related utility functions */
  93 static int      itimespecfix(struct timespec *ts);
  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_poll = mq_poll_fop,
 102         .fo_stat = mq_stat_fop,
 103         .fo_close = mq_close_fop,
 104         .fo_kqfilter = badfo_kqfilter,
 105         .fo_shutdown = badfo_shutdown
 106 };
 107
 108 /* Define a new malloc type for message queues */
 109 MALLOC_DECLARE(M_MQBUF);
 110 MALLOC_DEFINE(M_MQBUF, "mqueues", "Buffers to message queues");
 111
 112 /* Malloc arguments for object cache */
 113 struct objcache_malloc_args mqueue_malloc_args = {
 114         sizeof(struct mqueue), M_MQBUF };
 115
 116 /* Spinlock around the process list */
 117 extern struct spinlock allproc_spin;
 118
 119 /*
 120  * Initialize POSIX message queue subsystem.
 121  */
 122 void
 123 mqueue_sysinit(void)
 124 {
 125         mqmsg_cache = objcache_create("mqmsg_cache",
 126             0,          /* infinite depot's capacity */
 127             0,          /* default magazine's capacity */
 128             NULL,       /* constructor */
 129             NULL,       /* deconstructor */
 130             NULL,
 131             objcache_malloc_alloc,
 132             objcache_malloc_free,
 133             &mqueue_malloc_args);
 134
 135         lockinit(&mqlist_mtx, "mqlist_mtx", 0, LK_CANRECURSE);
 136 }
 137
 138 /*
 139  * Free the message.
 140  */
 141 static void
 142 mqueue_freemsg(struct mq_msg *msg, const size_t size)
 143 {
 144
 145         if (size > MQ_DEF_MSGSIZE)
 146                 kfree(msg, M_MQBUF);
 147         else
 148                 objcache_put(mqmsg_cache, msg);
 149 }
 150
 151 /*
 152  * Destroy the message queue.
 153  */
 154 static void
 155 mqueue_destroy(struct mqueue *mq)
 156 {
 157         struct mq_msg *msg;
 158         size_t msz;
 159         u_int i;
 160
 161         /* Note MQ_PQSIZE + 1. */
 162         for (i = 0; i < MQ_PQSIZE + 1; i++) {
 163                 while ((msg = TAILQ_FIRST(&mq->mq_head[i])) != NULL) {
 164                         TAILQ_REMOVE(&mq->mq_head[i], msg, msg_queue);
 165                         msz = sizeof(struct mq_msg) + msg->msg_len;
 166                         mqueue_freemsg(msg, msz);
 167                 }
 168         }
 169         lockuninit(&mq->mq_mtx);
 170         kfree(mq, M_MQBUF);
 171 }
 172
 173 /*
 174  * Lookup for file name in general list of message queues.
 175  *  => locks the message queue
 176  */
 177 static void *
 178 mqueue_lookup(char *name)
 179 {
 180         struct mqueue *mq;
 181
 182         KKASSERT(lockstatus(&mqlist_mtx, curthread));
 183
 184         LIST_FOREACH(mq, &mqueue_head, mq_list) {
 185                 if (strncmp(mq->mq_name, name, MQ_NAMELEN) == 0) {
 186                         lockmgr(&mq->mq_mtx, LK_EXCLUSIVE);
 187                         return mq;
 188                 }
 189         }
 190
 191         return NULL;
 192 }
 193
 194 /*
 195  * mqueue_get: get the mqueue from the descriptor.
 196  *  => locks the message queue, if found.
 197  *  => hold a reference on the file descriptor.
 198  */
 199 static int
 200 mqueue_get(struct lwp *l, mqd_t mqd, file_t **fpr)
 201 {
 202         struct mqueue *mq;
 203         file_t *fp;
 204
 205         fp = holdfp(curproc->p_fd, (int)mqd, -1);       /* XXX: Why -1 ? */
 206         if (__predict_false(fp == NULL))
 207                 return EBADF;
 208
 209         if (__predict_false(fp->f_type != DTYPE_MQUEUE)) {
 210                 fdrop(fp);
 211                 return EBADF;
 212         }
 213         mq = fp->f_data;
 214         lockmgr(&mq->mq_mtx, LK_EXCLUSIVE);
 215
 216         *fpr = fp;
 217         return 0;
 218 }
 219
 220 /*
 221  * mqueue_linear_insert: perform linear insert according to the message
 222  * priority into the reserved queue (MQ_PQRESQ).  Reserved queue is a
 223  * sorted list used only when mq_prio_max is increased via sysctl.
 224  */
 225 static inline void
 226 mqueue_linear_insert(struct mqueue *mq, struct mq_msg *msg)
 227 {
 228         struct mq_msg *mit;
 229
 230         TAILQ_FOREACH(mit, &mq->mq_head[MQ_PQRESQ], msg_queue) {
 231                 if (msg->msg_prio > mit->msg_prio)
 232                         break;
 233         }
 234         if (mit == NULL) {
 235                 TAILQ_INSERT_TAIL(&mq->mq_head[MQ_PQRESQ], msg, msg_queue);
 236         } else {
 237                 TAILQ_INSERT_BEFORE(mit, msg, msg_queue);
 238         }
 239 }
 240
 241 /*
 242  * Validate input.
 243  */
 244 int
 245 itimespecfix(struct timespec *ts)
 246 {
 247         if (ts->tv_sec < 0 || ts->tv_nsec < 0 || ts->tv_nsec >= 1000000000)
 248                 return (EINVAL);
 249         if (ts->tv_sec == 0 && ts->tv_nsec != 0 && ts->tv_nsec < nstick)
 250                 ts->tv_nsec = nstick;
 251         return (0);
 252 }
 253
 254 /*
 255  * Compute number of ticks in the specified amount of time.
 256  */
 257 int
 258 tstohz(const struct timespec *ts)
 259 {
 260         struct timeval tv;
 261
 262         /*
 263          * usec has great enough resolution for hz, so convert to a
 264          * timeval and use tvtohz() above.
 265          */
 266         TIMESPEC_TO_TIMEVAL(&tv, ts);
 267         return tvtohz_high(&tv);        /* XXX Why _high() and not _low() ? */
 268 }
 269
 270 /*
 271  * Converter from struct timespec to the ticks.
 272  * Used by mq_timedreceive(), mq_timedsend().
 273  */
 274 int
 275 abstimeout2timo(struct timespec *ts, int *timo)
 276 {
 277         struct timespec tsd;
 278         int error;
 279
 280         getnanotime(&tsd);
 281         timespecsub(ts, &tsd);
 282         if (ts->tv_sec < 0 || (ts->tv_sec == 0 && ts->tv_nsec <= 0)) {
 283                 return ETIMEDOUT;
 284         }
 285         error = itimespecfix(ts);
 286         if (error) {
 287                 return error;
 288         }
 289         *timo = tstohz(ts);
 290         KKASSERT(*timo != 0);
 291
 292         return 0;
 293 }
 294
 295 static int
 296 mq_stat_fop(file_t *fp, struct stat *st, struct ucred *cred)
 297 {
 298         struct mqueue *mq = fp->f_data;
 299
 300         (void)memset(st, 0, sizeof(*st));
 301
 302         lockmgr(&mq->mq_mtx, LK_EXCLUSIVE);
 303         st->st_mode = mq->mq_mode;
 304         st->st_uid = mq->mq_euid;
 305         st->st_gid = mq->mq_egid;
 306         st->st_atimespec = mq->mq_atime;
 307         st->st_mtimespec = mq->mq_mtime;
 308         /*st->st_ctimespec = st->st_birthtimespec = mq->mq_btime;*/
 309         st->st_uid = fp->f_cred->cr_uid;
 310         st->st_gid = fp->f_cred->cr_svgid;
 311         lockmgr(&mq->mq_mtx, LK_RELEASE);
 312
 313         return 0;
 314 }
 315
 316 static int
 317 mq_poll_fop(file_t *fp, int events, struct ucred *cred)
 318 {
 319         struct mqueue *mq = fp->f_data;
 320         int revents = 0;
 321
 322         lockmgr(&mq->mq_mtx, LK_EXCLUSIVE);
 323         if (events & (POLLIN | POLLRDNORM)) {
 324                 /* Ready for receiving, if there are messages in the queue */
 325                 if (mq->mq_attrib.mq_curmsgs)
 326                         revents |= (POLLIN | POLLRDNORM);
 327                 else
 328                         selrecord(curthread, &mq->mq_rsel);
 329         }
 330         if (events & (POLLOUT | POLLWRNORM)) {
 331                 /* Ready for sending, if the message queue is not full */
 332                 if (mq->mq_attrib.mq_curmsgs < mq->mq_attrib.mq_maxmsg)
 333                         revents |= (POLLOUT | POLLWRNORM);
 334                 else
 335                         selrecord(curthread, &mq->mq_wsel);
 336         }
 337         lockmgr(&mq->mq_mtx, LK_RELEASE);
 338
 339         return revents;
 340 }
 341
 342 static int
 343 mq_close_fop(file_t *fp)
 344 {
 345         struct proc *p = curproc;
 346         struct mqueue *mq = fp->f_data;
 347         bool destroy;
 348
 349         lockmgr(&mqlist_mtx, LK_EXCLUSIVE);
 350         lockmgr(&mq->mq_mtx, LK_EXCLUSIVE);
 351
 352         /* Decrease the counters */
 353         p->p_mqueue_cnt--;
 354         mq->mq_refcnt--;
 355
 356         /* Remove notification if registered for this process */
 357         if (mq->mq_notify_proc == p)
 358                 mq->mq_notify_proc = NULL;
 359
 360         /*
 361          * If this is the last reference and mqueue is marked for unlink,
 362          * remove and later destroy the message queue.
 363          */
 364         if (mq->mq_refcnt == 0 && (mq->mq_attrib.mq_flags & MQ_UNLINK)) {
 365                 LIST_REMOVE(mq, mq_list);
 366                 destroy = true;
 367         } else
 368                 destroy = false;
 369
 370         lockmgr(&mq->mq_mtx, LK_RELEASE);
 371         lockmgr(&mqlist_mtx, LK_RELEASE);
 372
 373         if (destroy)
 374                 mqueue_destroy(mq);
 375
 376         return 0;
 377 }
 378
 379 /*
 380  * General mqueue system calls.
 381  */
 382
 383 int
 384 sys_mq_open(struct mq_open_args *uap)
 385 {
 386         /* {
 387                 syscallarg(const char *) name;
 388                 syscallarg(int) oflag;
 389                 syscallarg(mode_t) mode;
 390                 syscallarg(struct mq_attr) attr;
 391         } */
 392         struct thread *td = curthread;
 393         struct proc *p = td->td_proc;
 394         struct filedesc *fdp = p->p_fd;
 395         struct mqueue *mq, *mq_new = NULL;
 396         file_t *fp;
 397         char *name;
 398         int mqd, error, oflag;
 399
 400         /* Check access mode flags */
 401         oflag = SCARG(uap, oflag);
 402         if ((oflag & O_ACCMODE) == (O_WRONLY | O_RDWR)) {
 403                 return EINVAL;
 404         }
 405
 406         /* Get the name from the user-space */
 407         name = kmalloc(MQ_NAMELEN, M_MQBUF, M_WAITOK | M_ZERO);
 408         error = copyinstr(SCARG(uap, name), name, MQ_NAMELEN - 1, NULL);
 409         if (error) {
 410                 kfree(name, M_MQBUF);
 411                 return error;
 412         }
 413
 414         if (oflag & O_CREAT) {
 415                 struct mq_attr attr;
 416                 u_int i;
 417
 418                 /* Check the limit */
 419                 if (p->p_mqueue_cnt == mq_open_max) {
 420                         kfree(name, M_MQBUF);
 421                         return EMFILE;
 422                 }
 423
 424                 /* Empty name is invalid */
 425                 if (name[0] == '\0') {
 426                         kfree(name, M_MQBUF);
 427                         return EINVAL;
 428                 }
 429
 430                 /* Check for mqueue attributes */
 431                 if (SCARG(uap, attr)) {
 432                         error = copyin(SCARG(uap, attr), &attr,
 433                                 sizeof(struct mq_attr));
 434                         if (error) {
 435                                 kfree(name, M_MQBUF);
 436                                 return error;
 437                         }
 438                         if (attr.mq_maxmsg <= 0 || attr.mq_msgsize <= 0 ||
 439                             attr.mq_msgsize > mq_max_msgsize) {
 440                                 kfree(name, M_MQBUF);
 441                                 return EINVAL;
 442                         }
 443                         attr.mq_curmsgs = 0;
 444                 } else {
 445                         memset(&attr, 0, sizeof(struct mq_attr));
 446                         attr.mq_maxmsg = mq_def_maxmsg;
 447                         attr.mq_msgsize =
 448                             MQ_DEF_MSGSIZE - sizeof(struct mq_msg);
 449                 }
 450
 451                 /*
 452                  * Allocate new mqueue, initialize data structures,
 453                  * copy the name, attributes and set the flag.
 454                  */
 455                 mq_new = kmalloc(sizeof(struct mqueue), M_MQBUF, M_WAITOK | M_ZERO);
 456
 457                 lockinit(&mq_new->mq_mtx, "mq_new->mq_mtx", 0, LK_CANRECURSE);
 458                 for (i = 0; i < (MQ_PQSIZE + 1); i++) {
 459                         TAILQ_INIT(&mq_new->mq_head[i]);
 460                 }
 461
 462                 strlcpy(mq_new->mq_name, name, MQ_NAMELEN);
 463                 memcpy(&mq_new->mq_attrib, &attr, sizeof(struct mq_attr));
 464
 465                 /*CTASSERT((O_MASK & (MQ_UNLINK | MQ_RECEIVE)) == 0);*/
 466                 /* mq_new->mq_attrib.mq_flags = (O_MASK & oflag); */
 467                 mq_new->mq_attrib.mq_flags = oflag;
 468
 469                 /* Store mode and effective UID with GID */
 470                 mq_new->mq_mode = ((SCARG(uap, mode) &
 471                     ~p->p_fd->fd_cmask) & ALLPERMS) & ~S_ISTXT;
 472                 mq_new->mq_euid = td->td_ucred->cr_uid;
 473                 mq_new->mq_egid = td->td_ucred->cr_svgid;
 474         }
 475
 476         /* Allocate file structure and descriptor */
 477         error = falloc(td->td_lwp, &fp, &mqd);
 478         if (error) {
 479                 if (mq_new)
 480                         mqueue_destroy(mq_new);
 481                 kfree(name, M_MQBUF);
 482                 return error;
 483         }
 484         fp->f_type = DTYPE_MQUEUE;
 485         fp->f_flag = FFLAGS(oflag) & (FREAD | FWRITE);
 486         fp->f_ops = &mqops;
 487
 488         /* Look up for mqueue with such name */
 489         lockmgr(&mqlist_mtx, LK_EXCLUSIVE);
 490         mq = mqueue_lookup(name);
 491         if (mq) {
 492                 int acc_mode;
 493
 494                 KKASSERT(lockstatus(&mq->mq_mtx, curthread));
 495
 496                 /* Check if mqueue is not marked as unlinking */
 497                 if (mq->mq_attrib.mq_flags & MQ_UNLINK) {
 498                         error = EACCES;
 499                         goto exit;
 500                 }
 501                 /* Fail if O_EXCL is set, and mqueue already exists */
 502                 if ((oflag & O_CREAT) && (oflag & O_EXCL)) {
 503                         error = EEXIST;
 504                         goto exit;
 505                 }
 506
 507                 /*
 508                  * Check the permissions. Note the difference between
 509                  * VREAD/VWRITE and FREAD/FWRITE.
 510                  */
 511                 acc_mode = 0;
 512                 if (fp->f_flag & FREAD) {
 513                         acc_mode |= VREAD;
 514                 }
 515                 if (fp->f_flag & FWRITE) {
 516                         acc_mode |= VWRITE;
 517                 }
 518                 if (vaccess(VNON, mq->mq_mode, mq->mq_euid, mq->mq_egid,
 519                         acc_mode, td->td_ucred)) {
 520
 521                         error = EACCES;
 522                         goto exit;
 523                 }
 524         } else {
 525                 /* Fail if mqueue neither exists, nor we create it */
 526                 if ((oflag & O_CREAT) == 0) {
 527                         lockmgr(&mqlist_mtx, LK_RELEASE);
 528                         KKASSERT(mq_new == NULL);
 529                         fsetfd(fdp, NULL, mqd);
 530                         fp->f_ops = &badfileops;
 531                         fdrop(fp);
 532                         kfree(name, M_MQBUF);
 533                         return ENOENT;
 534                 }
 535
 536                 /* Check the limit */
 537                 if (p->p_mqueue_cnt == mq_open_max) {
 538                         error = EMFILE;
 539                         goto exit;
 540                 }
 541
 542                 /* Insert the queue to the list */
 543                 mq = mq_new;
 544                 lockmgr(&mq->mq_mtx, LK_EXCLUSIVE);
 545                 LIST_INSERT_HEAD(&mqueue_head, mq, mq_list);
 546                 mq_new = NULL;
 547                 getnanotime(&mq->mq_btime);
 548                 mq->mq_atime = mq->mq_mtime = mq->mq_btime;
 549         }
 550
 551         /* Increase the counters, and make descriptor ready */
 552         p->p_mqueue_cnt++;
 553         mq->mq_refcnt++;
 554         fp->f_data = mq;
 555 exit:
 556         lockmgr(&mq->mq_mtx, LK_RELEASE);
 557         lockmgr(&mqlist_mtx, LK_RELEASE);
 558
 559         if (mq_new)
 560                 mqueue_destroy(mq_new);
 561         if (error) {
 562                 fsetfd(fdp, NULL, mqd);
 563                 fp->f_ops = &badfileops;
 564         } else {
 565                 fsetfd(fdp, fp, mqd);
 566                 uap->sysmsg_result = mqd;
 567         }
 568         fdrop(fp);
 569         kfree(name, M_MQBUF);
 570
 571         return error;
 572 }
 573
 574 int
 575 sys_mq_close(struct mq_close_args *uap)
 576 {
 577         return sys_close((void *)uap);
 578 }
 579
 580 /*
 581  * Primary mq_receive1() function.
 582  */
 583 int
 584 mq_receive1(struct lwp *l, mqd_t mqdes, void *msg_ptr, size_t msg_len,
 585     unsigned *msg_prio, struct timespec *ts, ssize_t *mlen)
 586 {
 587         file_t *fp = NULL;
 588         struct mqueue *mq;
 589         struct mq_msg *msg = NULL;
 590         struct mq_attr *mqattr;
 591         u_int idx;
 592         int error;
 593
 594         /* Get the message queue */
 595         error = mqueue_get(l, mqdes, &fp);
 596         if (error) {
 597                 return error;
 598         }
 599         mq = fp->f_data;
 600         if ((fp->f_flag & FREAD) == 0) {
 601                 error = EBADF;
 602                 goto error;
 603         }
 604         getnanotime(&mq->mq_atime);
 605         mqattr = &mq->mq_attrib;
 606
 607         /* Check the message size limits */
 608         if (msg_len < mqattr->mq_msgsize) {
 609                 error = EMSGSIZE;
 610                 goto error;
 611         }
 612
 613         /* Check if queue is empty */
 614         while (mqattr->mq_curmsgs == 0) {
 615                 int t;
 616
 617                 if (mqattr->mq_flags & O_NONBLOCK) {
 618                         error = EAGAIN;
 619                         goto error;
 620                 }
 621                 error = abstimeout2timo(ts, &t);
 622                 if (error) {
 623                         goto error;
 624                 }
 625                 /*
 626                  * Block until someone sends the message.
 627                  * While doing this, notification should not be sent.
 628                  */
 629                 mqattr->mq_flags |= MQ_RECEIVE;
 630                 error = tsleep(&mq->mq_send_cv, PCATCH, "mqsend", t);
 631                 mqattr->mq_flags &= ~MQ_RECEIVE;
 632                 if (error || (mqattr->mq_flags & MQ_UNLINK)) {
 633                         error = (error == EWOULDBLOCK) ? ETIMEDOUT : EINTR;
 634                         goto error;
 635                 }
 636         }
 637
 638
 639         /*
 640          * Find the highest priority message, and remove it from the queue.
 641          * At first, reserved queue is checked, bitmap is next.
 642          */
 643         msg = TAILQ_FIRST(&mq->mq_head[MQ_PQRESQ]);
 644         if (__predict_true(msg == NULL)) {
 645                 idx = ffs(mq->mq_bitmap);
 646                 msg = TAILQ_FIRST(&mq->mq_head[idx]);
 647                 KKASSERT(msg != NULL);
 648         } else {
 649                 idx = MQ_PQRESQ;
 650         }
 651         TAILQ_REMOVE(&mq->mq_head[idx], msg, msg_queue);
 652
 653         /* Unmark the bit, if last message. */
 654         if (__predict_true(idx) && TAILQ_EMPTY(&mq->mq_head[idx])) {
 655                 KKASSERT((MQ_PQSIZE - idx) == msg->msg_prio);
 656                 mq->mq_bitmap &= ~(1 << --idx);
 657         }
 658
 659         /* Decrement the counter and signal waiter, if any */
 660         mqattr->mq_curmsgs--;
 661         wakeup_one(&mq->mq_recv_cv);
 662
 663         /* Ready for sending now */
 664         selwakeup(&mq->mq_wsel);
 665 error:
 666         lockmgr(&mq->mq_mtx, LK_RELEASE);
 667         fdrop(fp);
 668         if (error)
 669                 return error;
 670
 671         /*
 672          * Copy the data to the user-space.
 673          * Note: According to POSIX, no message should be removed from the
 674          * queue in case of fail - this would be violated.
 675          */
 676         *mlen = msg->msg_len;
 677         error = copyout(msg->msg_ptr, msg_ptr, msg->msg_len);
 678         if (error == 0 && msg_prio)
 679                 error = copyout(&msg->msg_prio, msg_prio, sizeof(unsigned));
 680         mqueue_freemsg(msg, sizeof(struct mq_msg) + msg->msg_len);
 681
 682         return error;
 683 }
 684
 685 int
 686 sys_mq_receive(struct mq_receive_args *uap)
 687 {
 688         /* {
 689                 syscallarg(mqd_t) mqdes;
 690                 syscallarg(char *) msg_ptr;
 691                 syscallarg(size_t) msg_len;
 692                 syscallarg(unsigned *) msg_prio;
 693         } */
 694         ssize_t mlen;
 695         int error;
 696
 697         error = mq_receive1(curthread->td_lwp, SCARG(uap, mqdes), SCARG(uap, msg_ptr),
 698             SCARG(uap, msg_len), SCARG(uap, msg_prio), 0, &mlen);
 699         if (error == 0)
 700                 uap->sysmsg_result = mlen;
 701
 702         return error;
 703 }
 704
 705 int
 706 sys_mq_timedreceive(struct mq_timedreceive_args *uap)
 707 {
 708         /* {
 709                 syscallarg(mqd_t) mqdes;
 710                 syscallarg(char *) msg_ptr;
 711                 syscallarg(size_t) msg_len;
 712                 syscallarg(unsigned *) msg_prio;
 713                 syscallarg(const struct timespec *) abs_timeout;
 714         } */
 715         int error;
 716         ssize_t mlen;
 717         struct timespec ts, *tsp;
 718
 719         /* Get and convert time value */
 720         if (SCARG(uap, abs_timeout)) {
 721                 error = copyin(SCARG(uap, abs_timeout), &ts, sizeof(ts));
 722                 if (error)
 723                         return error;
 724                 tsp = &ts;
 725         } else {
 726                 tsp = NULL;
 727         }
 728
 729         error = mq_receive1(curthread->td_lwp, SCARG(uap, mqdes), SCARG(uap, msg_ptr),
 730             SCARG(uap, msg_len), SCARG(uap, msg_prio), tsp, &mlen);
 731         if (error == 0)
 732                 uap->sysmsg_result = mlen;
 733
 734         return error;
 735 }
 736
 737 /*
 738  * Primary mq_send1() function.
 739  */
 740 int
 741 mq_send1(struct lwp *l, mqd_t mqdes, const char *msg_ptr, size_t msg_len,
 742     unsigned msg_prio, struct timespec *ts)
 743 {
 744         file_t *fp = NULL;
 745         struct mqueue *mq;
 746         struct mq_msg *msg;
 747         struct mq_attr *mqattr;
 748         struct proc *notify = NULL;
 749         /*ksiginfo_t ksi;*/
 750         size_t size;
 751         int error;
 752
 753         /* Check the priority range */
 754         if (msg_prio >= mq_prio_max)
 755                 return EINVAL;
 756
 757         /* Allocate a new message */
 758         size = sizeof(struct mq_msg) + msg_len;
 759         if (size > mq_max_msgsize)
 760                 return EMSGSIZE;
 761
 762         if (size > MQ_DEF_MSGSIZE) {
 763                 msg = kmalloc(size, M_MQBUF, M_WAITOK);
 764         } else {
 765                 msg = objcache_get(mqmsg_cache, M_WAITOK);
 766         }
 767
 768         /* Get the data from user-space */
 769         error = copyin(msg_ptr, msg->msg_ptr, msg_len);
 770         if (error) {
 771                 mqueue_freemsg(msg, size);
 772                 return error;
 773         }
 774         msg->msg_len = msg_len;
 775         msg->msg_prio = msg_prio;
 776
 777         /* Get the mqueue */
 778         error = mqueue_get(l, mqdes, &fp);
 779         if (error) {
 780                 mqueue_freemsg(msg, size);
 781                 return error;
 782         }
 783         mq = fp->f_data;
 784         if ((fp->f_flag & FWRITE) == 0) {
 785                 error = EBADF;
 786                 goto error;
 787         }
 788         getnanotime(&mq->mq_mtime);
 789         mqattr = &mq->mq_attrib;
 790
 791         /* Check the message size limit */
 792         if (msg_len <= 0 || msg_len > mqattr->mq_msgsize) {
 793                 error = EMSGSIZE;
 794                 goto error;
 795         }
 796
 797         /* Check if queue is full */
 798         while (mqattr->mq_curmsgs >= mqattr->mq_maxmsg) {
 799                 int t;
 800
 801                 if (mqattr->mq_flags & O_NONBLOCK) {
 802                         error = EAGAIN;
 803                         goto error;
 804                 }
 805                 error = abstimeout2timo(ts, &t);
 806                 if (error) {
 807                         goto error;
 808                 }
 809                 /* Block until queue becomes available */
 810                 error = tsleep(&mq->mq_recv_cv, PCATCH, "mqrecv", t);
 811                 if (error || (mqattr->mq_flags & MQ_UNLINK)) {
 812                         error = (error == EWOULDBLOCK) ? ETIMEDOUT : error;
 813                         goto error;
 814                 }
 815         }
 816         KKASSERT(mq->mq_attrib.mq_curmsgs < mq->mq_attrib.mq_maxmsg);
 817
 818         /*
 819          * Insert message into the queue, according to the priority.
 820          * Note the difference between index and priority.
 821          */
 822         if (__predict_true(msg_prio < MQ_PQSIZE)) {
 823                 u_int idx = MQ_PQSIZE - msg_prio;
 824
 825                 KKASSERT(idx != MQ_PQRESQ);
 826                 TAILQ_INSERT_TAIL(&mq->mq_head[idx], msg, msg_queue);
 827                 mq->mq_bitmap |= (1 << --idx);
 828         } else {
 829                 mqueue_linear_insert(mq, msg);
 830         }
 831
 832         /* Check for the notify */
 833         if (mqattr->mq_curmsgs == 0 && mq->mq_notify_proc &&
 834             (mqattr->mq_flags & MQ_RECEIVE) == 0) {
 835                 /* Initialize the signal */
 836                 /*KSI_INIT(&ksi);*/
 837                 /*ksi.ksi_signo = mq->mq_sig_notify.sigev_signo;*/
 838                 /*ksi.ksi_code = SI_MESGQ;*/
 839                 /*ksi.ksi_value = mq->mq_sig_notify.sigev_value;*/
 840                 /* Unregister the process */
 841                 notify = mq->mq_notify_proc;
 842                 mq->mq_notify_proc = NULL;
 843         }
 844
 845         /* Increment the counter and signal waiter, if any */
 846         mqattr->mq_curmsgs++;
 847         wakeup_one(&mq->mq_send_cv);
 848
 849         /* Ready for receiving now */
 850         selwakeup(&mq->mq_rsel);
 851 error:
 852         lockmgr(&mq->mq_mtx, LK_RELEASE);
 853         fdrop(fp);
 854
 855         if (error) {
 856                 mqueue_freemsg(msg, size);
 857         } else if (notify) {
 858                 /* Send the notify, if needed */
 859                 spin_lock_wr(&allproc_spin);
 860                 /*kpsignal(notify, &ksi, NULL);*/
 861                 ksignal(notify, mq->mq_sig_notify.sigev_signo);
 862                 spin_unlock_wr(&allproc_spin);
 863         }
 864
 865         return error;
 866 }
 867
 868 int
 869 sys_mq_send(struct mq_send_args *uap)
 870 {
 871         /* {
 872                 syscallarg(mqd_t) mqdes;
 873                 syscallarg(const char *) msg_ptr;
 874                 syscallarg(size_t) msg_len;
 875                 syscallarg(unsigned) msg_prio;
 876         } */
 877
 878         return mq_send1(curthread->td_lwp, SCARG(uap, mqdes), SCARG(uap, msg_ptr),
 879             SCARG(uap, msg_len), SCARG(uap, msg_prio), 0);
 880 }
 881
 882 int
 883 sys_mq_timedsend(struct mq_timedsend_args *uap)
 884 {
 885         /* {
 886                 syscallarg(mqd_t) mqdes;
 887                 syscallarg(const char *) msg_ptr;
 888                 syscallarg(size_t) msg_len;
 889                 syscallarg(unsigned) msg_prio;
 890                 syscallarg(const struct timespec *) abs_timeout;
 891         } */
 892         struct timespec ts, *tsp;
 893         int error;
 894
 895         /* Get and convert time value */
 896         if (SCARG(uap, abs_timeout)) {
 897                 error = copyin(SCARG(uap, abs_timeout), &ts, sizeof(ts));
 898                 if (error)
 899                         return error;
 900                 tsp = &ts;
 901         } else {
 902                 tsp = NULL;
 903         }
 904
 905         return mq_send1(curthread->td_lwp, SCARG(uap, mqdes), SCARG(uap, msg_ptr),
 906             SCARG(uap, msg_len), SCARG(uap, msg_prio), tsp);
 907 }
 908
 909 int
 910 sys_mq_notify(struct mq_notify_args *uap)
 911 {
 912         /* {
 913                 syscallarg(mqd_t) mqdes;
 914                 syscallarg(const struct sigevent *) notification;
 915         } */
 916         file_t *fp = NULL;
 917         struct mqueue *mq;
 918         struct sigevent sig;
 919         int error;
 920
 921         if (SCARG(uap, notification)) {
 922                 /* Get the signal from user-space */
 923                 error = copyin(SCARG(uap, notification), &sig,
 924                     sizeof(struct sigevent));
 925                 if (error)
 926                         return error;
 927         }
 928
 929         error = mqueue_get(curthread->td_lwp, SCARG(uap, mqdes), &fp);
 930         if (error)
 931                 return error;
 932         mq = fp->f_data;
 933
 934         if (SCARG(uap, notification)) {
 935                 /* Register notification: set the signal and target process */
 936                 if (mq->mq_notify_proc == NULL) {
 937                         memcpy(&mq->mq_sig_notify, &sig,
 938                             sizeof(struct sigevent));
 939                         mq->mq_notify_proc = curproc;
 940                 } else {
 941                         /* Fail if someone else already registered */
 942                         error = EBUSY;
 943                 }
 944         } else {
 945                 /* Unregister the notification */
 946                 mq->mq_notify_proc = NULL;
 947         }
 948         lockmgr(&mq->mq_mtx, LK_RELEASE);
 949         fdrop(fp);
 950
 951         return error;
 952 }
 953
 954 int
 955 sys_mq_getattr(struct mq_getattr_args *uap)
 956 {
 957         /* {
 958                 syscallarg(mqd_t) mqdes;
 959                 syscallarg(struct mq_attr *) mqstat;
 960         } */
 961         file_t *fp = NULL;
 962         struct mqueue *mq;
 963         struct mq_attr attr;
 964         int error;
 965
 966         /* Get the message queue */
 967         error = mqueue_get(curthread->td_lwp, SCARG(uap, mqdes), &fp);
 968         if (error)
 969                 return error;
 970         mq = fp->f_data;
 971         memcpy(&attr, &mq->mq_attrib, sizeof(struct mq_attr));
 972         lockmgr(&mq->mq_mtx, LK_RELEASE);
 973         fdrop(fp);
 974
 975         return copyout(&attr, SCARG(uap, mqstat), sizeof(struct mq_attr));
 976 }
 977
 978 int
 979 sys_mq_setattr(struct mq_setattr_args *uap)
 980 {
 981         /* {
 982                 syscallarg(mqd_t) mqdes;
 983                 syscallarg(const struct mq_attr *) mqstat;
 984                 syscallarg(struct mq_attr *) omqstat;
 985         } */
 986         file_t *fp = NULL;
 987         struct mqueue *mq;
 988         struct mq_attr attr;
 989         int error, nonblock;
 990
 991         error = copyin(SCARG(uap, mqstat), &attr, sizeof(struct mq_attr));
 992         if (error)
 993                 return error;
 994         nonblock = (attr.mq_flags & O_NONBLOCK);
 995
 996         /* Get the message queue */
 997         error = mqueue_get(curthread->td_lwp, SCARG(uap, mqdes), &fp);
 998         if (error)
 999                 return error;
1000         mq = fp->f_data;
1001
1002         /* Copy the old attributes, if needed */
1003         if (SCARG(uap, omqstat))
1004                 memcpy(&attr, &mq->mq_attrib, sizeof(struct mq_attr));
1005
1006         /* Ignore everything, except O_NONBLOCK */
1007         if (nonblock)
1008                 mq->mq_attrib.mq_flags |= O_NONBLOCK;
1009         else
1010                 mq->mq_attrib.mq_flags &= ~O_NONBLOCK;
1011
1012         lockmgr(&mq->mq_mtx, LK_RELEASE);
1013         fdrop(fp);
1014
1015         /*
1016          * Copy the data to the user-space.
1017          * Note: According to POSIX, the new attributes should not be set in
1018          * case of fail - this would be violated.
1019          */
1020         if (SCARG(uap, omqstat))
1021                 error = copyout(&attr, SCARG(uap, omqstat),
1022                     sizeof(struct mq_attr));
1023
1024         return error;
1025 }
1026
1027 int
1028 sys_mq_unlink(struct mq_unlink_args *uap)
1029 {
1030         /* {
1031                 syscallarg(const char *) name;
1032         } */
1033         struct thread *td = curthread;
1034         struct mqueue *mq;
1035         char *name;
1036         int error, refcnt = 0;
1037
1038         /* Get the name from the user-space */
1039         name = kmalloc(MQ_NAMELEN, M_MQBUF, M_WAITOK | M_ZERO);
1040         error = copyinstr(SCARG(uap, name), name, MQ_NAMELEN - 1, NULL);
1041         if (error) {
1042                 kfree(name, M_MQBUF);
1043                 return error;
1044         }
1045
1046         /* Lookup for this file */
1047         lockmgr(&mqlist_mtx, LK_EXCLUSIVE);
1048         mq = mqueue_lookup(name);
1049         if (mq == NULL) {
1050                 error = ENOENT;
1051                 goto error;
1052         }
1053
1054         /* Check the permissions */
1055         if (td->td_ucred->cr_uid != mq->mq_euid &&
1056             priv_check(td, PRIV_ROOT) != 0) {
1057                 lockmgr(&mq->mq_mtx, LK_RELEASE);
1058                 error = EACCES;
1059                 goto error;
1060         }
1061
1062         /* Mark message queue as unlinking, before leaving the window */
1063         mq->mq_attrib.mq_flags |= MQ_UNLINK;
1064
1065         /* Wake up all waiters, if there are such */
1066         wakeup(&mq->mq_send_cv);
1067         wakeup(&mq->mq_recv_cv);
1068
1069         selwakeup(&mq->mq_rsel);
1070         selwakeup(&mq->mq_wsel);
1071
1072         refcnt = mq->mq_refcnt;
1073         if (refcnt == 0)
1074                 LIST_REMOVE(mq, mq_list);
1075
1076         lockmgr(&mq->mq_mtx, LK_RELEASE);
1077 error:
1078         lockmgr(&mqlist_mtx, LK_RELEASE);
1079
1080         /*
1081          * If there are no references - destroy the message
1082          * queue, otherwise, the last mq_close() will do that.
1083          */
1084         if (error == 0 && refcnt == 0)
1085                 mqueue_destroy(mq);
1086
1087         kfree(name, M_MQBUF);
1088         return error;
1089 }
1090
1091 /*
1092  * SysCtl.
1093  */
1094 SYSCTL_NODE(_kern, OID_AUTO, mqueue,
1095     CTLFLAG_RW, 0, "Message queue options");
1096
1097 SYSCTL_INT(_kern_mqueue, OID_AUTO, mq_open_max,
1098     CTLFLAG_RW, &mq_open_max, 0,
1099     "Maximal number of message queue descriptors per process");
1100
1101 SYSCTL_INT(_kern_mqueue, OID_AUTO, mq_prio_max,
1102     CTLFLAG_RW, &mq_prio_max, 0,
1103     "Maximal priority of the message");
1104
1105 SYSCTL_INT(_kern_mqueue, OID_AUTO, mq_max_msgsize,
1106     CTLFLAG_RW, &mq_max_msgsize, 0,
1107     "Maximal allowed size of the message");
1108
1109 SYSCTL_INT(_kern_mqueue, OID_AUTO, mq_def_maxmsg,
1110     CTLFLAG_RW, &mq_def_maxmsg, 0,
1111     "Default maximal message count");
1112
1113 SYSINIT(sys_mqueue_init, SI_SUB_PRE_DRIVERS, SI_ORDER_ANY, mqueue_sysinit, NULL);