ipc/mqueue.c

   1 /*
   2  * POSIX message queues filesystem for Linux.
   3  *
   4  * Copyright (C) 2003,2004  Krzysztof Benedyczak    (golbi@mat.uni.torun.pl)
   5  *                          Michal Wronski          (michal.wronski@gmail.com)
   6  *
   7  * Spinlocks:               Mohamed Abbas           (abbas.mohamed@intel.com)
   8  * Lockless receive & send, fd based notify:
   9  *                          Manfred Spraul          (manfred@colorfullife.com)
  10  *
  11  * Audit:                   George Wilson           (ltcgcw@us.ibm.com)
  12  *
  13  * This file is released under the GPL.
  14  */
  15
  16 #include <linux/capability.h>
  17 #include <linux/init.h>
  18 #include <linux/pagemap.h>
  19 #include <linux/file.h>
  20 #include <linux/mount.h>
  21 #include <linux/namei.h>
  22 #include <linux/sysctl.h>
  23 #include <linux/poll.h>
  24 #include <linux/mqueue.h>
  25 #include <linux/msg.h>
  26 #include <linux/skbuff.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/netlink.h>
  29 #include <linux/syscalls.h>
  30 #include <linux/audit.h>
  31 #include <linux/signal.h>
  32 #include <linux/mutex.h>
  33 #include <linux/nsproxy.h>
  34 #include <linux/pid.h>
  35 #include <linux/ipc_namespace.h>
  36 #include <linux/user_namespace.h>
  37 #include <linux/slab.h>
  38
  39 #include <net/sock.h>
  40 #include "util.h"
  41
  42 #define MQUEUE_MAGIC    0x19800202
  43 #define DIRENT_SIZE     20
  44 #define FILENT_SIZE     80
  45
  46 #define SEND            0
  47 #define RECV            1
  48
  49 #define STATE_NONE      0
  50 #define STATE_PENDING   1
  51 #define STATE_READY     2
  52
  53 struct posix_msg_tree_node {
  54         struct rb_node          rb_node;
  55         struct list_head        msg_list;
  56         int                     priority;
  57 };
  58
  59 struct ext_wait_queue {         /* queue of sleeping tasks */
  60         struct task_struct *task;
  61         struct list_head list;
  62         struct msg_msg *msg;    /* ptr of loaded message */
  63         int state;              /* one of STATE_* values */
  64 };
  65
  66 struct mqueue_inode_info {
  67         spinlock_t lock;
  68         struct inode vfs_inode;
  69         wait_queue_head_t wait_q;
  70
  71         struct rb_root msg_tree;
  72         struct mq_attr attr;
  73
  74         struct sigevent notify;
  75         struct pid* notify_owner;
  76         struct user_namespace *notify_user_ns;
  77         struct user_struct *user;       /* user who created, for accounting */
  78         struct sock *notify_sock;
  79         struct sk_buff *notify_cookie;
  80
  81         /* for tasks waiting for free space and messages, respectively */
  82         struct ext_wait_queue e_wait_q[2];
  83
  84         unsigned long qsize; /* size of queue in memory (sum of all msgs) */
  85 };
  86
  87 static const struct inode_operations mqueue_dir_inode_operations;
  88 static const struct file_operations mqueue_file_operations;
  89 static const struct super_operations mqueue_super_ops;
  90 static void remove_notification(struct mqueue_inode_info *info);
  91
  92 static struct kmem_cache *mqueue_inode_cachep;
  93
  94 static struct ctl_table_header * mq_sysctl_table;
  95
  96 static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
  97 {
  98         return container_of(inode, struct mqueue_inode_info, vfs_inode);
  99 }
 100
 101 /*
 102  * This routine should be called with the mq_lock held.
 103  */
 104 static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
 105 {
 106         return get_ipc_ns(inode->i_sb->s_fs_info);
 107 }
 108
 109 static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
 110 {
 111         struct ipc_namespace *ns;
 112
 113         spin_lock(&mq_lock);
 114         ns = __get_ns_from_inode(inode);
 115         spin_unlock(&mq_lock);
 116         return ns;
 117 }
 118
 119 /* Auxiliary functions to manipulate messages' list */
 120 static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
 121 {
 122         struct rb_node **p, *parent = NULL;
 123         struct posix_msg_tree_node *leaf;
 124
 125         p = &info->msg_tree.rb_node;
 126         while (*p) {
 127                 parent = *p;
 128                 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
 129
 130                 if (likely(leaf->priority == msg->m_type))
 131                         goto insert_msg;
 132                 else if (msg->m_type < leaf->priority)
 133                         p = &(*p)->rb_left;
 134                 else
 135                         p = &(*p)->rb_right;
 136         }
 137         leaf = kzalloc(sizeof(*leaf), GFP_ATOMIC);
 138         if (!leaf)
 139                 return -ENOMEM;
 140         rb_init_node(&leaf->rb_node);
 141         INIT_LIST_HEAD(&leaf->msg_list);
 142         leaf->priority = msg->m_type;
 143         rb_link_node(&leaf->rb_node, parent, p);
 144         rb_insert_color(&leaf->rb_node, &info->msg_tree);
 145         info->qsize += sizeof(struct posix_msg_tree_node);
 146 insert_msg:
 147         info->attr.mq_curmsgs++;
 148         info->qsize += msg->m_ts;
 149         list_add_tail(&msg->m_list, &leaf->msg_list);
 150         return 0;
 151 }
 152
 153 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
 154 {
 155         struct rb_node **p, *parent = NULL;
 156         struct posix_msg_tree_node *leaf;
 157         struct msg_msg *msg;
 158
 159 try_again:
 160         p = &info->msg_tree.rb_node;
 161         while (*p) {
 162                 parent = *p;
 163                 /*
 164                  * During insert, low priorities go to the left and high to the
 165                  * right.  On receive, we want the highest priorities first, so
 166                  * walk all the way to the right.
 167                  */
 168                 p = &(*p)->rb_right;
 169         }
 170         if (!parent) {
 171                 if (info->attr.mq_curmsgs) {
 172                         pr_warn_once("Inconsistency in POSIX message queue, "
 173                                      "no tree element, but supposedly messages "
 174                                      "should exist!\n");
 175                         info->attr.mq_curmsgs = 0;
 176                 }
 177                 return NULL;
 178         }
 179         leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
 180         if (list_empty(&leaf->msg_list)) {
 181                 pr_warn_once("Inconsistency in POSIX message queue, "
 182                              "empty leaf node but we haven't implemented "
 183                              "lazy leaf delete!\n");
 184                 rb_erase(&leaf->rb_node, &info->msg_tree);
 185                 info->qsize -= sizeof(struct posix_msg_tree_node);
 186                 kfree(leaf);
 187                 goto try_again;
 188         } else {
 189                 msg = list_first_entry(&leaf->msg_list,
 190                                        struct msg_msg, m_list);
 191                 list_del(&msg->m_list);
 192                 if (list_empty(&leaf->msg_list)) {
 193                         rb_erase(&leaf->rb_node, &info->msg_tree);
 194                         info->qsize -= sizeof(struct posix_msg_tree_node);
 195                         kfree(leaf);
 196                 }
 197         }
 198         info->attr.mq_curmsgs--;
 199         info->qsize -= msg->m_ts;
 200         return msg;
 201 }
 202
 203 static struct inode *mqueue_get_inode(struct super_block *sb,
 204                 struct ipc_namespace *ipc_ns, umode_t mode,
 205                 struct mq_attr *attr)
 206 {
 207         struct user_struct *u = current_user();
 208         struct inode *inode;
 209         int ret = -ENOMEM;
 210
 211         inode = new_inode(sb);
 212         if (!inode)
 213                 goto err;
 214
 215         inode->i_ino = get_next_ino();
 216         inode->i_mode = mode;
 217         inode->i_uid = current_fsuid();
 218         inode->i_gid = current_fsgid();
 219         inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME;
 220
 221         if (S_ISREG(mode)) {
 222                 struct mqueue_inode_info *info;
 223                 unsigned long mq_bytes, mq_treesize;
 224
 225                 inode->i_fop = &mqueue_file_operations;
 226                 inode->i_size = FILENT_SIZE;
 227                 /* mqueue specific info */
 228                 info = MQUEUE_I(inode);
 229                 spin_lock_init(&info->lock);
 230                 init_waitqueue_head(&info->wait_q);
 231                 INIT_LIST_HEAD(&info->e_wait_q[0].list);
 232                 INIT_LIST_HEAD(&info->e_wait_q[1].list);
 233                 info->notify_owner = NULL;
 234                 info->notify_user_ns = NULL;
 235                 info->qsize = 0;
 236                 info->user = NULL;      /* set when all is ok */
 237                 info->msg_tree = RB_ROOT;
 238                 memset(&info->attr, 0, sizeof(info->attr));
 239                 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
 240                                            ipc_ns->mq_msg_default);
 241                 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
 242                                             ipc_ns->mq_msgsize_default);
 243                 if (attr) {
 244                         info->attr.mq_maxmsg = attr->mq_maxmsg;
 245                         info->attr.mq_msgsize = attr->mq_msgsize;
 246                 }
 247                 /*
 248                  * We used to allocate a static array of pointers and account
 249                  * the size of that array as well as one msg_msg struct per
 250                  * possible message into the queue size. That's no longer
 251                  * accurate as the queue is now an rbtree and will grow and
 252                  * shrink depending on usage patterns.  We can, however, still
 253                  * account one msg_msg struct per message, but the nodes are
 254                  * allocated depending on priority usage, and most programs
 255                  * only use one, or a handful, of priorities.  However, since
 256                  * this is pinned memory, we need to assume worst case, so
 257                  * that means the min(mq_maxmsg, max_priorities) * struct
 258                  * posix_msg_tree_node.
 259                  */
 260                 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
 261                         min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
 262                         sizeof(struct posix_msg_tree_node);
 263
 264                 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
 265                                           info->attr.mq_msgsize);
 266
 267                 spin_lock(&mq_lock);
 268                 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
 269                     u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
 270                         spin_unlock(&mq_lock);
 271                         /* mqueue_evict_inode() releases info->messages */
 272                         ret = -EMFILE;
 273                         goto out_inode;
 274                 }
 275                 u->mq_bytes += mq_bytes;
 276                 spin_unlock(&mq_lock);
 277
 278                 /* all is ok */
 279                 info->user = get_uid(u);
 280         } else if (S_ISDIR(mode)) {
 281                 inc_nlink(inode);
 282                 /* Some things misbehave if size == 0 on a directory */
 283                 inode->i_size = 2 * DIRENT_SIZE;
 284                 inode->i_op = &mqueue_dir_inode_operations;
 285                 inode->i_fop = &simple_dir_operations;
 286         }
 287
 288         return inode;
 289 out_inode:
 290         iput(inode);
 291 err:
 292         return ERR_PTR(ret);
 293 }
 294
 295 static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
 296 {
 297         struct inode *inode;
 298         struct ipc_namespace *ns = data;
 299
 300         sb->s_blocksize = PAGE_CACHE_SIZE;
 301         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 302         sb->s_magic = MQUEUE_MAGIC;
 303         sb->s_op = &mqueue_super_ops;
 304
 305         inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
 306         if (IS_ERR(inode))
 307                 return PTR_ERR(inode);
 308
 309         sb->s_root = d_make_root(inode);
 310         if (!sb->s_root)
 311                 return -ENOMEM;
 312         return 0;
 313 }
 314
 315 static struct dentry *mqueue_mount(struct file_system_type *fs_type,
 316                          int flags, const char *dev_name,
 317                          void *data)
 318 {
 319         if (!(flags & MS_KERNMOUNT))
 320                 data = current->nsproxy->ipc_ns;
 321         return mount_ns(fs_type, flags, data, mqueue_fill_super);
 322 }
 323
 324 static void init_once(void *foo)
 325 {
 326         struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
 327
 328         inode_init_once(&p->vfs_inode);
 329 }
 330
 331 static struct inode *mqueue_alloc_inode(struct super_block *sb)
 332 {
 333         struct mqueue_inode_info *ei;
 334
 335         ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
 336         if (!ei)
 337                 return NULL;
 338         return &ei->vfs_inode;
 339 }
 340
 341 static void mqueue_i_callback(struct rcu_head *head)
 342 {
 343         struct inode *inode = container_of(head, struct inode, i_rcu);
 344         kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
 345 }
 346
 347 static void mqueue_destroy_inode(struct inode *inode)
 348 {
 349         call_rcu(&inode->i_rcu, mqueue_i_callback);
 350 }
 351
 352 static void mqueue_evict_inode(struct inode *inode)
 353 {
 354         struct mqueue_inode_info *info;
 355         struct user_struct *user;
 356         unsigned long mq_bytes, mq_treesize;
 357         struct ipc_namespace *ipc_ns;
 358         struct msg_msg *msg;
 359
 360         clear_inode(inode);
 361
 362         if (S_ISDIR(inode->i_mode))
 363                 return;
 364
 365         ipc_ns = get_ns_from_inode(inode);
 366         info = MQUEUE_I(inode);
 367         spin_lock(&info->lock);
 368         while ((msg = msg_get(info)) != NULL)
 369                 free_msg(msg);
 370         spin_unlock(&info->lock);
 371
 372         /* Total amount of bytes accounted for the mqueue */
 373         mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
 374                 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
 375                 sizeof(struct posix_msg_tree_node);
 376
 377         mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
 378                                   info->attr.mq_msgsize);
 379
 380         user = info->user;
 381         if (user) {
 382                 spin_lock(&mq_lock);
 383                 user->mq_bytes -= mq_bytes;
 384                 /*
 385                  * get_ns_from_inode() ensures that the
 386                  * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
 387                  * to which we now hold a reference, or it is NULL.
 388                  * We can't put it here under mq_lock, though.
 389                  */
 390                 if (ipc_ns)
 391                         ipc_ns->mq_queues_count--;
 392                 spin_unlock(&mq_lock);
 393                 free_uid(user);
 394         }
 395         if (ipc_ns)
 396                 put_ipc_ns(ipc_ns);
 397 }
 398
 399 static int mqueue_create(struct inode *dir, struct dentry *dentry,
 400                                 umode_t mode, struct nameidata *nd)
 401 {
 402         struct inode *inode;
 403         struct mq_attr *attr = dentry->d_fsdata;
 404         int error;
 405         struct ipc_namespace *ipc_ns;
 406
 407         spin_lock(&mq_lock);
 408         ipc_ns = __get_ns_from_inode(dir);
 409         if (!ipc_ns) {
 410                 error = -EACCES;
 411                 goto out_unlock;
 412         }
 413         if (ipc_ns->mq_queues_count >= HARD_QUEUESMAX ||
 414             (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
 415              !capable(CAP_SYS_RESOURCE))) {
 416                 error = -ENOSPC;
 417                 goto out_unlock;
 418         }
 419         ipc_ns->mq_queues_count++;
 420         spin_unlock(&mq_lock);
 421
 422         inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
 423         if (IS_ERR(inode)) {
 424                 error = PTR_ERR(inode);
 425                 spin_lock(&mq_lock);
 426                 ipc_ns->mq_queues_count--;
 427                 goto out_unlock;
 428         }
 429
 430         put_ipc_ns(ipc_ns);
 431         dir->i_size += DIRENT_SIZE;
 432         dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
 433
 434         d_instantiate(dentry, inode);
 435         dget(dentry);
 436         return 0;
 437 out_unlock:
 438         spin_unlock(&mq_lock);
 439         if (ipc_ns)
 440                 put_ipc_ns(ipc_ns);
 441         return error;
 442 }
 443
 444 static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
 445 {
 446         struct inode *inode = dentry->d_inode;
 447
 448         dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
 449         dir->i_size -= DIRENT_SIZE;
 450         drop_nlink(inode);
 451         dput(dentry);
 452         return 0;
 453 }
 454
 455 /*
 456 *       This is routine for system read from queue file.
 457 *       To avoid mess with doing here some sort of mq_receive we allow
 458 *       to read only queue size & notification info (the only values
 459 *       that are interesting from user point of view and aren't accessible
 460 *       through std routines)
 461 */
 462 static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
 463                                 size_t count, loff_t *off)
 464 {
 465         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
 466         char buffer[FILENT_SIZE];
 467         ssize_t ret;
 468
 469         spin_lock(&info->lock);
 470         snprintf(buffer, sizeof(buffer),
 471                         "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
 472                         info->qsize,
 473                         info->notify_owner ? info->notify.sigev_notify : 0,
 474                         (info->notify_owner &&
 475                          info->notify.sigev_notify == SIGEV_SIGNAL) ?
 476                                 info->notify.sigev_signo : 0,
 477                         pid_vnr(info->notify_owner));
 478         spin_unlock(&info->lock);
 479         buffer[sizeof(buffer)-1] = '\0';
 480
 481         ret = simple_read_from_buffer(u_data, count, off, buffer,
 482                                 strlen(buffer));
 483         if (ret <= 0)
 484                 return ret;
 485
 486         filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME;
 487         return ret;
 488 }
 489
 490 static int mqueue_flush_file(struct file *filp, fl_owner_t id)
 491 {
 492         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
 493
 494         spin_lock(&info->lock);
 495         if (task_tgid(current) == info->notify_owner)
 496                 remove_notification(info);
 497
 498         spin_unlock(&info->lock);
 499         return 0;
 500 }
 501
 502 static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
 503 {
 504         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
 505         int retval = 0;
 506
 507         poll_wait(filp, &info->wait_q, poll_tab);
 508
 509         spin_lock(&info->lock);
 510         if (info->attr.mq_curmsgs)
 511                 retval = POLLIN | POLLRDNORM;
 512
 513         if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
 514                 retval |= POLLOUT | POLLWRNORM;
 515         spin_unlock(&info->lock);
 516
 517         return retval;
 518 }
 519
 520 /* Adds current to info->e_wait_q[sr] before element with smaller prio */
 521 static void wq_add(struct mqueue_inode_info *info, int sr,
 522                         struct ext_wait_queue *ewp)
 523 {
 524         struct ext_wait_queue *walk;
 525
 526         ewp->task = current;
 527
 528         list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
 529                 if (walk->task->static_prio <= current->static_prio) {
 530                         list_add_tail(&ewp->list, &walk->list);
 531                         return;
 532                 }
 533         }
 534         list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
 535 }
 536
 537 /*
 538  * Puts current task to sleep. Caller must hold queue lock. After return
 539  * lock isn't held.
 540  * sr: SEND or RECV
 541  */
 542 static int wq_sleep(struct mqueue_inode_info *info, int sr,
 543                     ktime_t *timeout, struct ext_wait_queue *ewp)
 544 {
 545         int retval;
 546         signed long time;
 547
 548         wq_add(info, sr, ewp);
 549
 550         for (;;) {
 551                 set_current_state(TASK_INTERRUPTIBLE);
 552
 553                 spin_unlock(&info->lock);
 554                 time = schedule_hrtimeout_range_clock(timeout, 0,
 555                         HRTIMER_MODE_ABS, CLOCK_REALTIME);
 556
 557                 while (ewp->state == STATE_PENDING)
 558                         cpu_relax();
 559
 560                 if (ewp->state == STATE_READY) {
 561                         retval = 0;
 562                         goto out;
 563                 }
 564                 spin_lock(&info->lock);
 565                 if (ewp->state == STATE_READY) {
 566                         retval = 0;
 567                         goto out_unlock;
 568                 }
 569                 if (signal_pending(current)) {
 570                         retval = -ERESTARTSYS;
 571                         break;
 572                 }
 573                 if (time == 0) {
 574                         retval = -ETIMEDOUT;
 575                         break;
 576                 }
 577         }
 578         list_del(&ewp->list);
 579 out_unlock:
 580         spin_unlock(&info->lock);
 581 out:
 582         return retval;
 583 }
 584
 585 /*
 586  * Returns waiting task that should be serviced first or NULL if none exists
 587  */
 588 static struct ext_wait_queue *wq_get_first_waiter(
 589                 struct mqueue_inode_info *info, int sr)
 590 {
 591         struct list_head *ptr;
 592
 593         ptr = info->e_wait_q[sr].list.prev;
 594         if (ptr == &info->e_wait_q[sr].list)
 595                 return NULL;
 596         return list_entry(ptr, struct ext_wait_queue, list);
 597 }
 598
 599
 600 static inline void set_cookie(struct sk_buff *skb, char code)
 601 {
 602         ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
 603 }
 604
 605 /*
 606  * The next function is only to split too long sys_mq_timedsend
 607  */
 608 static void __do_notify(struct mqueue_inode_info *info)
 609 {
 610         /* notification
 611          * invoked when there is registered process and there isn't process
 612          * waiting synchronously for message AND state of queue changed from
 613          * empty to not empty. Here we are sure that no one is waiting
 614          * synchronously. */
 615         if (info->notify_owner &&
 616             info->attr.mq_curmsgs == 1) {
 617                 struct siginfo sig_i;
 618                 switch (info->notify.sigev_notify) {
 619                 case SIGEV_NONE:
 620                         break;
 621                 case SIGEV_SIGNAL:
 622                         /* sends signal */
 623
 624                         sig_i.si_signo = info->notify.sigev_signo;
 625                         sig_i.si_errno = 0;
 626                         sig_i.si_code = SI_MESGQ;
 627                         sig_i.si_value = info->notify.sigev_value;
 628                         /* map current pid/uid into info->owner's namespaces */
 629                         rcu_read_lock();
 630                         sig_i.si_pid = task_tgid_nr_ns(current,
 631                                                 ns_of_pid(info->notify_owner));
 632                         sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
 633                         rcu_read_unlock();
 634
 635                         kill_pid_info(info->notify.sigev_signo,
 636                                       &sig_i, info->notify_owner);
 637                         break;
 638                 case SIGEV_THREAD:
 639                         set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
 640                         netlink_sendskb(info->notify_sock, info->notify_cookie);
 641                         break;
 642                 }
 643                 /* after notification unregisters process */
 644                 put_pid(info->notify_owner);
 645                 put_user_ns(info->notify_user_ns);
 646                 info->notify_owner = NULL;
 647                 info->notify_user_ns = NULL;
 648         }
 649         wake_up(&info->wait_q);
 650 }
 651
 652 static int prepare_timeout(const struct timespec __user *u_abs_timeout,
 653                            ktime_t *expires, struct timespec *ts)
 654 {
 655         if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec)))
 656                 return -EFAULT;
 657         if (!timespec_valid(ts))
 658                 return -EINVAL;
 659
 660         *expires = timespec_to_ktime(*ts);
 661         return 0;
 662 }
 663
 664 static void remove_notification(struct mqueue_inode_info *info)
 665 {
 666         if (info->notify_owner != NULL &&
 667             info->notify.sigev_notify == SIGEV_THREAD) {
 668                 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
 669                 netlink_sendskb(info->notify_sock, info->notify_cookie);
 670         }
 671         put_pid(info->notify_owner);
 672         put_user_ns(info->notify_user_ns);
 673         info->notify_owner = NULL;
 674         info->notify_user_ns = NULL;
 675 }
 676
 677 static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
 678 {
 679         int mq_treesize;
 680         unsigned long total_size;
 681
 682         if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
 683                 return 0;
 684         if (capable(CAP_SYS_RESOURCE)) {
 685                 if (attr->mq_maxmsg > HARD_MSGMAX ||
 686                     attr->mq_msgsize > HARD_MSGSIZEMAX)
 687                         return 0;
 688         } else {
 689                 if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
 690                                 attr->mq_msgsize > ipc_ns->mq_msgsize_max)
 691                         return 0;
 692         }
 693         /* check for overflow */
 694         if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
 695                 return 0;
 696         mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) +
 697                 min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) *
 698                 sizeof(struct posix_msg_tree_node);
 699         total_size = attr->mq_maxmsg * attr->mq_msgsize;
 700         if (total_size + mq_treesize < total_size)
 701                 return 0;
 702         return 1;
 703 }
 704
 705 /*
 706  * Invoked when creating a new queue via sys_mq_open
 707  */
 708 static struct file *do_create(struct ipc_namespace *ipc_ns, struct dentry *dir,
 709                         struct dentry *dentry, int oflag, umode_t mode,
 710                         struct mq_attr *attr)
 711 {
 712         const struct cred *cred = current_cred();
 713         struct file *result;
 714         int ret;
 715
 716         if (attr) {
 717                 if (!mq_attr_ok(ipc_ns, attr)) {
 718                         ret = -EINVAL;
 719                         goto out;
 720                 }
 721                 /* store for use during create */
 722                 dentry->d_fsdata = attr;
 723         }
 724
 725         mode &= ~current_umask();
 726         ret = mnt_want_write(ipc_ns->mq_mnt);
 727         if (ret)
 728                 goto out;
 729         ret = vfs_create(dir->d_inode, dentry, mode, NULL);
 730         dentry->d_fsdata = NULL;
 731         if (ret)
 732                 goto out_drop_write;
 733
 734         result = dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
 735         /*
 736          * dentry_open() took a persistent mnt_want_write(),
 737          * so we can now drop this one.
 738          */
 739         mnt_drop_write(ipc_ns->mq_mnt);
 740         return result;
 741
 742 out_drop_write:
 743         mnt_drop_write(ipc_ns->mq_mnt);
 744 out:
 745         dput(dentry);
 746         mntput(ipc_ns->mq_mnt);
 747         return ERR_PTR(ret);
 748 }
 749
 750 /* Opens existing queue */
 751 static struct file *do_open(struct ipc_namespace *ipc_ns,
 752                                 struct dentry *dentry, int oflag)
 753 {
 754         int ret;
 755         const struct cred *cred = current_cred();
 756
 757         static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
 758                                                   MAY_READ | MAY_WRITE };
 759
 760         if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
 761                 ret = -EINVAL;
 762                 goto err;
 763         }
 764
 765         if (inode_permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE])) {
 766                 ret = -EACCES;
 767                 goto err;
 768         }
 769
 770         return dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
 771
 772 err:
 773         dput(dentry);
 774         mntput(ipc_ns->mq_mnt);
 775         return ERR_PTR(ret);
 776 }
 777
 778 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
 779                 struct mq_attr __user *, u_attr)
 780 {
 781         struct dentry *dentry;
 782         struct file *filp;
 783         char *name;
 784         struct mq_attr attr;
 785         int fd, error;
 786         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
 787
 788         if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
 789                 return -EFAULT;
 790
 791         audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
 792
 793         if (IS_ERR(name = getname(u_name)))
 794                 return PTR_ERR(name);
 795
 796         fd = get_unused_fd_flags(O_CLOEXEC);
 797         if (fd < 0)
 798                 goto out_putname;
 799
 800         mutex_lock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
 801         dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
 802         if (IS_ERR(dentry)) {
 803                 error = PTR_ERR(dentry);
 804                 goto out_putfd;
 805         }
 806         mntget(ipc_ns->mq_mnt);
 807
 808         if (oflag & O_CREAT) {
 809                 if (dentry->d_inode) {  /* entry already exists */
 810                         audit_inode(name, dentry);
 811                         if (oflag & O_EXCL) {
 812                                 error = -EEXIST;
 813                                 goto out;
 814                         }
 815                         filp = do_open(ipc_ns, dentry, oflag);
 816                 } else {
 817                         filp = do_create(ipc_ns, ipc_ns->mq_mnt->mnt_root,
 818                                                 dentry, oflag, mode,
 819                                                 u_attr ? &attr : NULL);
 820                 }
 821         } else {
 822                 if (!dentry->d_inode) {
 823                         error = -ENOENT;
 824                         goto out;
 825                 }
 826                 audit_inode(name, dentry);
 827                 filp = do_open(ipc_ns, dentry, oflag);
 828         }
 829
 830         if (IS_ERR(filp)) {
 831                 error = PTR_ERR(filp);
 832                 goto out_putfd;
 833         }
 834
 835         fd_install(fd, filp);
 836         goto out_upsem;
 837
 838 out:
 839         dput(dentry);
 840         mntput(ipc_ns->mq_mnt);
 841 out_putfd:
 842         put_unused_fd(fd);
 843         fd = error;
 844 out_upsem:
 845         mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
 846 out_putname:
 847         putname(name);
 848         return fd;
 849 }
 850
 851 SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
 852 {
 853         int err;
 854         char *name;
 855         struct dentry *dentry;
 856         struct inode *inode = NULL;
 857         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
 858
 859         name = getname(u_name);
 860         if (IS_ERR(name))
 861                 return PTR_ERR(name);
 862
 863         mutex_lock_nested(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex,
 864                         I_MUTEX_PARENT);
 865         dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
 866         if (IS_ERR(dentry)) {
 867                 err = PTR_ERR(dentry);
 868                 goto out_unlock;
 869         }
 870
 871         if (!dentry->d_inode) {
 872                 err = -ENOENT;
 873                 goto out_err;
 874         }
 875
 876         inode = dentry->d_inode;
 877         if (inode)
 878                 ihold(inode);
 879         err = mnt_want_write(ipc_ns->mq_mnt);
 880         if (err)
 881                 goto out_err;
 882         err = vfs_unlink(dentry->d_parent->d_inode, dentry);
 883         mnt_drop_write(ipc_ns->mq_mnt);
 884 out_err:
 885         dput(dentry);
 886
 887 out_unlock:
 888         mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
 889         putname(name);
 890         if (inode)
 891                 iput(inode);
 892
 893         return err;
 894 }
 895
 896 /* Pipelined send and receive functions.
 897  *
 898  * If a receiver finds no waiting message, then it registers itself in the
 899  * list of waiting receivers. A sender checks that list before adding the new
 900  * message into the message array. If there is a waiting receiver, then it
 901  * bypasses the message array and directly hands the message over to the
 902  * receiver.
 903  * The receiver accepts the message and returns without grabbing the queue
 904  * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
 905  * are necessary. The same algorithm is used for sysv semaphores, see
 906  * ipc/sem.c for more details.
 907  *
 908  * The same algorithm is used for senders.
 909  */
 910
 911 /* pipelined_send() - send a message directly to the task waiting in
 912  * sys_mq_timedreceive() (without inserting message into a queue).
 913  */
 914 static inline void pipelined_send(struct mqueue_inode_info *info,
 915                                   struct msg_msg *message,
 916                                   struct ext_wait_queue *receiver)
 917 {
 918         receiver->msg = message;
 919         list_del(&receiver->list);
 920         receiver->state = STATE_PENDING;
 921         wake_up_process(receiver->task);
 922         smp_wmb();
 923         receiver->state = STATE_READY;
 924 }
 925
 926 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
 927  * gets its message and put to the queue (we have one free place for sure). */
 928 static inline void pipelined_receive(struct mqueue_inode_info *info)
 929 {
 930         struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
 931
 932         if (!sender) {
 933                 /* for poll */
 934                 wake_up_interruptible(&info->wait_q);
 935                 return;
 936         }
 937         if (msg_insert(sender->msg, info))
 938                 return;
 939         list_del(&sender->list);
 940         sender->state = STATE_PENDING;
 941         wake_up_process(sender->task);
 942         smp_wmb();
 943         sender->state = STATE_READY;
 944 }
 945
 946 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
 947                 size_t, msg_len, unsigned int, msg_prio,
 948                 const struct timespec __user *, u_abs_timeout)
 949 {
 950         struct file *filp;
 951         struct inode *inode;
 952         struct ext_wait_queue wait;
 953         struct ext_wait_queue *receiver;
 954         struct msg_msg *msg_ptr;
 955         struct mqueue_inode_info *info;
 956         ktime_t expires, *timeout = NULL;
 957         struct timespec ts;
 958         int ret;
 959
 960         if (u_abs_timeout) {
 961                 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
 962                 if (res)
 963                         return res;
 964                 timeout = &expires;
 965         }
 966
 967         if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
 968                 return -EINVAL;
 969
 970         audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL);
 971
 972         filp = fget(mqdes);
 973         if (unlikely(!filp)) {
 974                 ret = -EBADF;
 975                 goto out;
 976         }
 977
 978         inode = filp->f_path.dentry->d_inode;
 979         if (unlikely(filp->f_op != &mqueue_file_operations)) {
 980                 ret = -EBADF;
 981                 goto out_fput;
 982         }
 983         info = MQUEUE_I(inode);
 984         audit_inode(NULL, filp->f_path.dentry);
 985
 986         if (unlikely(!(filp->f_mode & FMODE_WRITE))) {
 987                 ret = -EBADF;
 988                 goto out_fput;
 989         }
 990
 991         if (unlikely(msg_len > info->attr.mq_msgsize)) {
 992                 ret = -EMSGSIZE;
 993                 goto out_fput;
 994         }
 995
 996         /* First try to allocate memory, before doing anything with
 997          * existing queues. */
 998         msg_ptr = load_msg(u_msg_ptr, msg_len);
 999         if (IS_ERR(msg_ptr)) {
1000                 ret = PTR_ERR(msg_ptr);
1001                 goto out_fput;
1002         }
1003         msg_ptr->m_ts = msg_len;
1004         msg_ptr->m_type = msg_prio;
1005
1006         spin_lock(&info->lock);
1007
1008         if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1009                 if (filp->f_flags & O_NONBLOCK) {
1010                         spin_unlock(&info->lock);
1011                         ret = -EAGAIN;
1012                 } else {
1013                         wait.task = current;
1014                         wait.msg = (void *) msg_ptr;
1015                         wait.state = STATE_NONE;
1016                         ret = wq_sleep(info, SEND, timeout, &wait);
1017                 }
1018                 if (ret < 0)
1019                         free_msg(msg_ptr);
1020         } else {
1021                 receiver = wq_get_first_waiter(info, RECV);
1022                 if (receiver) {
1023                         pipelined_send(info, msg_ptr, receiver);
1024                 } else {
1025                         /* adds message to the queue */
1026                         if (msg_insert(msg_ptr, info)) {
1027                                 free_msg(msg_ptr);
1028                                 ret = -ENOMEM;
1029                                 spin_unlock(&info->lock);
1030                                 goto out_fput;
1031                         }
1032                         __do_notify(info);
1033                 }
1034                 inode->i_atime = inode->i_mtime = inode->i_ctime =
1035                                 CURRENT_TIME;
1036                 spin_unlock(&info->lock);
1037                 ret = 0;
1038         }
1039 out_fput:
1040         fput(filp);
1041 out:
1042         return ret;
1043 }
1044
1045 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1046                 size_t, msg_len, unsigned int __user *, u_msg_prio,
1047                 const struct timespec __user *, u_abs_timeout)
1048 {
1049         ssize_t ret;
1050         struct msg_msg *msg_ptr;
1051         struct file *filp;
1052         struct inode *inode;
1053         struct mqueue_inode_info *info;
1054         struct ext_wait_queue wait;
1055         ktime_t expires, *timeout = NULL;
1056         struct timespec ts;
1057
1058         if (u_abs_timeout) {
1059                 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
1060                 if (res)
1061                         return res;
1062                 timeout = &expires;
1063         }
1064
1065         audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL);
1066
1067         filp = fget(mqdes);
1068         if (unlikely(!filp)) {
1069                 ret = -EBADF;
1070                 goto out;
1071         }
1072
1073         inode = filp->f_path.dentry->d_inode;
1074         if (unlikely(filp->f_op != &mqueue_file_operations)) {
1075                 ret = -EBADF;
1076                 goto out_fput;
1077         }
1078         info = MQUEUE_I(inode);
1079         audit_inode(NULL, filp->f_path.dentry);
1080
1081         if (unlikely(!(filp->f_mode & FMODE_READ))) {
1082                 ret = -EBADF;
1083                 goto out_fput;
1084         }
1085
1086         /* checks if buffer is big enough */
1087         if (unlikely(msg_len < info->attr.mq_msgsize)) {
1088                 ret = -EMSGSIZE;
1089                 goto out_fput;
1090         }
1091
1092         spin_lock(&info->lock);
1093         if (info->attr.mq_curmsgs == 0) {
1094                 if (filp->f_flags & O_NONBLOCK) {
1095                         spin_unlock(&info->lock);
1096                         ret = -EAGAIN;
1097                 } else {
1098                         wait.task = current;
1099                         wait.state = STATE_NONE;
1100                         ret = wq_sleep(info, RECV, timeout, &wait);
1101                         msg_ptr = wait.msg;
1102                 }
1103         } else {
1104                 msg_ptr = msg_get(info);
1105
1106                 inode->i_atime = inode->i_mtime = inode->i_ctime =
1107                                 CURRENT_TIME;
1108
1109                 /* There is now free space in queue. */
1110                 pipelined_receive(info);
1111                 spin_unlock(&info->lock);
1112                 ret = 0;
1113         }
1114         if (ret == 0) {
1115                 ret = msg_ptr->m_ts;
1116
1117                 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1118                         store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1119                         ret = -EFAULT;
1120                 }
1121                 free_msg(msg_ptr);
1122         }
1123 out_fput:
1124         fput(filp);
1125 out:
1126         return ret;
1127 }
1128
1129 /*
1130  * Notes: the case when user wants us to deregister (with NULL as pointer)
1131  * and he isn't currently owner of notification, will be silently discarded.
1132  * It isn't explicitly defined in the POSIX.
1133  */
1134 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1135                 const struct sigevent __user *, u_notification)
1136 {
1137         int ret;
1138         struct file *filp;
1139         struct sock *sock;
1140         struct inode *inode;
1141         struct sigevent notification;
1142         struct mqueue_inode_info *info;
1143         struct sk_buff *nc;
1144
1145         if (u_notification) {
1146                 if (copy_from_user(&notification, u_notification,
1147                                         sizeof(struct sigevent)))
1148                         return -EFAULT;
1149         }
1150
1151         audit_mq_notify(mqdes, u_notification ? &notification : NULL);
1152
1153         nc = NULL;
1154         sock = NULL;
1155         if (u_notification != NULL) {
1156                 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1157                              notification.sigev_notify != SIGEV_SIGNAL &&
1158                              notification.sigev_notify != SIGEV_THREAD))
1159                         return -EINVAL;
1160                 if (notification.sigev_notify == SIGEV_SIGNAL &&
1161                         !valid_signal(notification.sigev_signo)) {
1162                         return -EINVAL;
1163                 }
1164                 if (notification.sigev_notify == SIGEV_THREAD) {
1165                         long timeo;
1166
1167                         /* create the notify skb */
1168                         nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1169                         if (!nc) {
1170                                 ret = -ENOMEM;
1171                                 goto out;
1172                         }
1173                         if (copy_from_user(nc->data,
1174                                         notification.sigev_value.sival_ptr,
1175                                         NOTIFY_COOKIE_LEN)) {
1176                                 ret = -EFAULT;
1177                                 goto out;
1178                         }
1179
1180                         /* TODO: add a header? */
1181                         skb_put(nc, NOTIFY_COOKIE_LEN);
1182                         /* and attach it to the socket */
1183 retry:
1184                         filp = fget(notification.sigev_signo);
1185                         if (!filp) {
1186                                 ret = -EBADF;
1187                                 goto out;
1188                         }
1189                         sock = netlink_getsockbyfilp(filp);
1190                         fput(filp);
1191                         if (IS_ERR(sock)) {
1192                                 ret = PTR_ERR(sock);
1193                                 sock = NULL;
1194                                 goto out;
1195                         }
1196
1197                         timeo = MAX_SCHEDULE_TIMEOUT;
1198                         ret = netlink_attachskb(sock, nc, &timeo, NULL);
1199                         if (ret == 1)
1200                                 goto retry;
1201                         if (ret) {
1202                                 sock = NULL;
1203                                 nc = NULL;
1204                                 goto out;
1205                         }
1206                 }
1207         }
1208
1209         filp = fget(mqdes);
1210         if (!filp) {
1211                 ret = -EBADF;
1212                 goto out;
1213         }
1214
1215         inode = filp->f_path.dentry->d_inode;
1216         if (unlikely(filp->f_op != &mqueue_file_operations)) {
1217                 ret = -EBADF;
1218                 goto out_fput;
1219         }
1220         info = MQUEUE_I(inode);
1221
1222         ret = 0;
1223         spin_lock(&info->lock);
1224         if (u_notification == NULL) {
1225                 if (info->notify_owner == task_tgid(current)) {
1226                         remove_notification(info);
1227                         inode->i_atime = inode->i_ctime = CURRENT_TIME;
1228                 }
1229         } else if (info->notify_owner != NULL) {
1230                 ret = -EBUSY;
1231         } else {
1232                 switch (notification.sigev_notify) {
1233                 case SIGEV_NONE:
1234                         info->notify.sigev_notify = SIGEV_NONE;
1235                         break;
1236                 case SIGEV_THREAD:
1237                         info->notify_sock = sock;
1238                         info->notify_cookie = nc;
1239                         sock = NULL;
1240                         nc = NULL;
1241                         info->notify.sigev_notify = SIGEV_THREAD;
1242                         break;
1243                 case SIGEV_SIGNAL:
1244                         info->notify.sigev_signo = notification.sigev_signo;
1245                         info->notify.sigev_value = notification.sigev_value;
1246                         info->notify.sigev_notify = SIGEV_SIGNAL;
1247                         break;
1248                 }
1249
1250                 info->notify_owner = get_pid(task_tgid(current));
1251                 info->notify_user_ns = get_user_ns(current_user_ns());
1252                 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1253         }
1254         spin_unlock(&info->lock);
1255 out_fput:
1256         fput(filp);
1257 out:
1258         if (sock) {
1259                 netlink_detachskb(sock, nc);
1260         } else if (nc) {
1261                 dev_kfree_skb(nc);
1262         }
1263         return ret;
1264 }
1265
1266 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1267                 const struct mq_attr __user *, u_mqstat,
1268                 struct mq_attr __user *, u_omqstat)
1269 {
1270         int ret;
1271         struct mq_attr mqstat, omqstat;
1272         struct file *filp;
1273         struct inode *inode;
1274         struct mqueue_inode_info *info;
1275
1276         if (u_mqstat != NULL) {
1277                 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1278                         return -EFAULT;
1279                 if (mqstat.mq_flags & (~O_NONBLOCK))
1280                         return -EINVAL;
1281         }
1282
1283         filp = fget(mqdes);
1284         if (!filp) {
1285                 ret = -EBADF;
1286                 goto out;
1287         }
1288
1289         inode = filp->f_path.dentry->d_inode;
1290         if (unlikely(filp->f_op != &mqueue_file_operations)) {
1291                 ret = -EBADF;
1292                 goto out_fput;
1293         }
1294         info = MQUEUE_I(inode);
1295
1296         spin_lock(&info->lock);
1297
1298         omqstat = info->attr;
1299         omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
1300         if (u_mqstat) {
1301                 audit_mq_getsetattr(mqdes, &mqstat);
1302                 spin_lock(&filp->f_lock);
1303                 if (mqstat.mq_flags & O_NONBLOCK)
1304                         filp->f_flags |= O_NONBLOCK;
1305                 else
1306                         filp->f_flags &= ~O_NONBLOCK;
1307                 spin_unlock(&filp->f_lock);
1308
1309                 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1310         }
1311
1312         spin_unlock(&info->lock);
1313
1314         ret = 0;
1315         if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1316                                                 sizeof(struct mq_attr)))
1317                 ret = -EFAULT;
1318
1319 out_fput:
1320         fput(filp);
1321 out:
1322         return ret;
1323 }
1324
1325 static const struct inode_operations mqueue_dir_inode_operations = {
1326         .lookup = simple_lookup,
1327         .create = mqueue_create,
1328         .unlink = mqueue_unlink,
1329 };
1330
1331 static const struct file_operations mqueue_file_operations = {
1332         .flush = mqueue_flush_file,
1333         .poll = mqueue_poll_file,
1334         .read = mqueue_read_file,
1335         .llseek = default_llseek,
1336 };
1337
1338 static const struct super_operations mqueue_super_ops = {
1339         .alloc_inode = mqueue_alloc_inode,
1340         .destroy_inode = mqueue_destroy_inode,
1341         .evict_inode = mqueue_evict_inode,
1342         .statfs = simple_statfs,
1343 };
1344
1345 static struct file_system_type mqueue_fs_type = {
1346         .name = "mqueue",
1347         .mount = mqueue_mount,
1348         .kill_sb = kill_litter_super,
1349 };
1350
1351 int mq_init_ns(struct ipc_namespace *ns)
1352 {
1353         ns->mq_queues_count  = 0;
1354         ns->mq_queues_max    = DFLT_QUEUESMAX;
1355         ns->mq_msg_max       = DFLT_MSGMAX;
1356         ns->mq_msgsize_max   = DFLT_MSGSIZEMAX;
1357         ns->mq_msg_default   = DFLT_MSG;
1358         ns->mq_msgsize_default  = DFLT_MSGSIZE;
1359
1360         ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1361         if (IS_ERR(ns->mq_mnt)) {
1362                 int err = PTR_ERR(ns->mq_mnt);
1363                 ns->mq_mnt = NULL;
1364                 return err;
1365         }
1366         return 0;
1367 }
1368
1369 void mq_clear_sbinfo(struct ipc_namespace *ns)
1370 {
1371         ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1372 }
1373
1374 void mq_put_mnt(struct ipc_namespace *ns)
1375 {
1376         kern_unmount(ns->mq_mnt);
1377 }
1378
1379 static int __init init_mqueue_fs(void)
1380 {
1381         int error;
1382
1383         mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1384                                 sizeof(struct mqueue_inode_info), 0,
1385                                 SLAB_HWCACHE_ALIGN, init_once);
1386         if (mqueue_inode_cachep == NULL)
1387                 return -ENOMEM;
1388
1389         /* ignore failures - they are not fatal */
1390         mq_sysctl_table = mq_register_sysctl_table();
1391
1392         error = register_filesystem(&mqueue_fs_type);
1393         if (error)
1394                 goto out_sysctl;
1395
1396         spin_lock_init(&mq_lock);
1397
1398         error = mq_init_ns(&init_ipc_ns);
1399         if (error)
1400                 goto out_filesystem;
1401
1402         return 0;
1403
1404 out_filesystem:
1405         unregister_filesystem(&mqueue_fs_type);
1406 out_sysctl:
1407         if (mq_sysctl_table)
1408                 unregister_sysctl_table(mq_sysctl_table);
1409         kmem_cache_destroy(mqueue_inode_cachep);
1410         return error;
1411 }
1412
1413 __initcall(init_mqueue_fs);