ipc/mqueue.c

   1 /*
   2  * POSIX message queues filesystem for Linux.
   3  *
   4  * Copyright (C) 2003,2004  Krzysztof Benedyczak    ([email protected])
   5  *                          Michal Wronski          ([email protected])
   6  *
   7  * Spinlocks:               Mohamed Abbas           ([email protected])
   8  * Lockless receive & send, fd based notify:
   9  *                          Manfred Spraul          ([email protected])
  10  *
  11  * Audit:                   George Wilson           ([email protected])
  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 posix_msg_tree_node *node_cache;
  73         struct mq_attr attr;
  74
  75         struct sigevent notify;
  76         struct pid* notify_owner;
  77         struct user_namespace *notify_user_ns;
  78         struct user_struct *user;       /* user who created, for accounting */
  79         struct sock *notify_sock;
  80         struct sk_buff *notify_cookie;
  81
  82         /* for tasks waiting for free space and messages, respectively */
  83         struct ext_wait_queue e_wait_q[2];
  84
  85         unsigned long qsize; /* size of queue in memory (sum of all msgs) */
  86 };
  87
  88 static const struct inode_operations mqueue_dir_inode_operations;
  89 static const struct file_operations mqueue_file_operations;
  90 static const struct super_operations mqueue_super_ops;
  91 static void remove_notification(struct mqueue_inode_info *info);
  92
  93 static struct kmem_cache *mqueue_inode_cachep;
  94
  95 static struct ctl_table_header * mq_sysctl_table;
  96
  97 static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
  98 {
  99         return container_of(inode, struct mqueue_inode_info, vfs_inode);
 100 }
 101
 102 /*
 103  * This routine should be called with the mq_lock held.
 104  */
 105 static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
 106 {
 107         return get_ipc_ns(inode->i_sb->s_fs_info);
 108 }
 109
 110 static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
 111 {
 112         struct ipc_namespace *ns;
 113
 114         spin_lock(&mq_lock);
 115         ns = __get_ns_from_inode(inode);
 116         spin_unlock(&mq_lock);
 117         return ns;
 118 }
 119
 120 /* Auxiliary functions to manipulate messages' list */
 121 static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
 122 {
 123         struct rb_node **p, *parent = NULL;
 124         struct posix_msg_tree_node *leaf;
 125
 126         p = &info->msg_tree.rb_node;
 127         while (*p) {
 128                 parent = *p;
 129                 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
 130
 131                 if (likely(leaf->priority == msg->m_type))
 132                         goto insert_msg;
 133                 else if (msg->m_type < leaf->priority)
 134                         p = &(*p)->rb_left;
 135                 else
 136                         p = &(*p)->rb_right;
 137         }
 138         if (info->node_cache) {
 139                 leaf = info->node_cache;
 140                 info->node_cache = NULL;
 141         } else {
 142                 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
 143                 if (!leaf)
 144                         return -ENOMEM;
 145                 rb_init_node(&leaf->rb_node);
 146                 INIT_LIST_HEAD(&leaf->msg_list);
 147                 info->qsize += sizeof(*leaf);
 148         }
 149         leaf->priority = msg->m_type;
 150         rb_link_node(&leaf->rb_node, parent, p);
 151         rb_insert_color(&leaf->rb_node, &info->msg_tree);
 152 insert_msg:
 153         info->attr.mq_curmsgs++;
 154         info->qsize += msg->m_ts;
 155         list_add_tail(&msg->m_list, &leaf->msg_list);
 156         return 0;
 157 }
 158
 159 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
 160 {
 161         struct rb_node **p, *parent = NULL;
 162         struct posix_msg_tree_node *leaf;
 163         struct msg_msg *msg;
 164
 165 try_again:
 166         p = &info->msg_tree.rb_node;
 167         while (*p) {
 168                 parent = *p;
 169                 /*
 170                  * During insert, low priorities go to the left and high to the
 171                  * right.  On receive, we want the highest priorities first, so
 172                  * walk all the way to the right.
 173                  */
 174                 p = &(*p)->rb_right;
 175         }
 176         if (!parent) {
 177                 if (info->attr.mq_curmsgs) {
 178                         pr_warn_once("Inconsistency in POSIX message queue, "
 179                                      "no tree element, but supposedly messages "
 180                                      "should exist!\n");
 181                         info->attr.mq_curmsgs = 0;
 182                 }
 183                 return NULL;
 184         }
 185         leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
 186         if (unlikely(list_empty(&leaf->msg_list))) {
 187                 pr_warn_once("Inconsistency in POSIX message queue, "
 188                              "empty leaf node but we haven't implemented "
 189                              "lazy leaf delete!\n");
 190                 rb_erase(&leaf->rb_node, &info->msg_tree);
 191                 if (info->node_cache) {
 192                         info->qsize -= sizeof(*leaf);
 193                         kfree(leaf);
 194                 } else {
 195                         info->node_cache = leaf;
 196                 }
 197                 goto try_again;
 198         } else {
 199                 msg = list_first_entry(&leaf->msg_list,
 200                                        struct msg_msg, m_list);
 201                 list_del(&msg->m_list);
 202                 if (list_empty(&leaf->msg_list)) {
 203                         rb_erase(&leaf->rb_node, &info->msg_tree);
 204                         if (info->node_cache) {
 205                                 info->qsize -= sizeof(*leaf);
 206                                 kfree(leaf);
 207                         } else {
 208                                 info->node_cache = leaf;
 209                         }
 210                 }
 211         }
 212         info->attr.mq_curmsgs--;
 213         info->qsize -= msg->m_ts;
 214         return msg;
 215 }
 216
 217 static struct inode *mqueue_get_inode(struct super_block *sb,
 218                 struct ipc_namespace *ipc_ns, umode_t mode,
 219                 struct mq_attr *attr)
 220 {
 221         struct user_struct *u = current_user();
 222         struct inode *inode;
 223         int ret = -ENOMEM;
 224
 225         inode = new_inode(sb);
 226         if (!inode)
 227                 goto err;
 228
 229         inode->i_ino = get_next_ino();
 230         inode->i_mode = mode;
 231         inode->i_uid = current_fsuid();
 232         inode->i_gid = current_fsgid();
 233         inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME;
 234
 235         if (S_ISREG(mode)) {
 236                 struct mqueue_inode_info *info;
 237                 unsigned long mq_bytes, mq_treesize;
 238
 239                 inode->i_fop = &mqueue_file_operations;
 240                 inode->i_size = FILENT_SIZE;
 241                 /* mqueue specific info */
 242                 info = MQUEUE_I(inode);
 243                 spin_lock_init(&info->lock);
 244                 init_waitqueue_head(&info->wait_q);
 245                 INIT_LIST_HEAD(&info->e_wait_q[0].list);
 246                 INIT_LIST_HEAD(&info->e_wait_q[1].list);
 247                 info->notify_owner = NULL;
 248                 info->notify_user_ns = NULL;
 249                 info->qsize = 0;
 250                 info->user = NULL;      /* set when all is ok */
 251                 info->msg_tree = RB_ROOT;
 252                 info->node_cache = NULL;
 253                 memset(&info->attr, 0, sizeof(info->attr));
 254                 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
 255                                            ipc_ns->mq_msg_default);
 256                 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
 257                                             ipc_ns->mq_msgsize_default);
 258                 if (attr) {
 259                         info->attr.mq_maxmsg = attr->mq_maxmsg;
 260                         info->attr.mq_msgsize = attr->mq_msgsize;
 261                 }
 262                 /*
 263                  * We used to allocate a static array of pointers and account
 264                  * the size of that array as well as one msg_msg struct per
 265                  * possible message into the queue size. That's no longer
 266                  * accurate as the queue is now an rbtree and will grow and
 267                  * shrink depending on usage patterns.  We can, however, still
 268                  * account one msg_msg struct per message, but the nodes are
 269                  * allocated depending on priority usage, and most programs
 270                  * only use one, or a handful, of priorities.  However, since
 271                  * this is pinned memory, we need to assume worst case, so
 272                  * that means the min(mq_maxmsg, max_priorities) * struct
 273                  * posix_msg_tree_node.
 274                  */
 275                 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
 276                         min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
 277                         sizeof(struct posix_msg_tree_node);
 278
 279                 mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
 280                                           info->attr.mq_msgsize);
 281
 282                 spin_lock(&mq_lock);
 283                 if (u->mq_bytes + mq_bytes < u->mq_bytes ||
 284                     u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
 285                         spin_unlock(&mq_lock);
 286                         /* mqueue_evict_inode() releases info->messages */
 287                         ret = -EMFILE;
 288                         goto out_inode;
 289                 }
 290                 u->mq_bytes += mq_bytes;
 291                 spin_unlock(&mq_lock);
 292
 293                 /* all is ok */
 294                 info->user = get_uid(u);
 295         } else if (S_ISDIR(mode)) {
 296                 inc_nlink(inode);
 297                 /* Some things misbehave if size == 0 on a directory */
 298                 inode->i_size = 2 * DIRENT_SIZE;
 299                 inode->i_op = &mqueue_dir_inode_operations;
 300                 inode->i_fop = &simple_dir_operations;
 301         }
 302
 303         return inode;
 304 out_inode:
 305         iput(inode);
 306 err:
 307         return ERR_PTR(ret);
 308 }
 309
 310 static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
 311 {
 312         struct inode *inode;
 313         struct ipc_namespace *ns = data;
 314
 315         sb->s_blocksize = PAGE_CACHE_SIZE;
 316         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 317         sb->s_magic = MQUEUE_MAGIC;
 318         sb->s_op = &mqueue_super_ops;
 319
 320         inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
 321         if (IS_ERR(inode))
 322                 return PTR_ERR(inode);
 323
 324         sb->s_root = d_make_root(inode);
 325         if (!sb->s_root)
 326                 return -ENOMEM;
 327         return 0;
 328 }
 329
 330 static struct dentry *mqueue_mount(struct file_system_type *fs_type,
 331                          int flags, const char *dev_name,
 332                          void *data)
 333 {
 334         if (!(flags & MS_KERNMOUNT))
 335                 data = current->nsproxy->ipc_ns;
 336         return mount_ns(fs_type, flags, data, mqueue_fill_super);
 337 }
 338
 339 static void init_once(void *foo)
 340 {
 341         struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
 342
 343         inode_init_once(&p->vfs_inode);
 344 }
 345
 346 static struct inode *mqueue_alloc_inode(struct super_block *sb)
 347 {
 348         struct mqueue_inode_info *ei;
 349
 350         ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
 351         if (!ei)
 352                 return NULL;
 353         return &ei->vfs_inode;
 354 }
 355
 356 static void mqueue_i_callback(struct rcu_head *head)
 357 {
 358         struct inode *inode = container_of(head, struct inode, i_rcu);
 359         kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
 360 }
 361
 362 static void mqueue_destroy_inode(struct inode *inode)
 363 {
 364         call_rcu(&inode->i_rcu, mqueue_i_callback);
 365 }
 366
 367 static void mqueue_evict_inode(struct inode *inode)
 368 {
 369         struct mqueue_inode_info *info;
 370         struct user_struct *user;
 371         unsigned long mq_bytes, mq_treesize;
 372         struct ipc_namespace *ipc_ns;
 373         struct msg_msg *msg;
 374
 375         clear_inode(inode);
 376
 377         if (S_ISDIR(inode->i_mode))
 378                 return;
 379
 380         ipc_ns = get_ns_from_inode(inode);
 381         info = MQUEUE_I(inode);
 382         spin_lock(&info->lock);
 383         while ((msg = msg_get(info)) != NULL)
 384                 free_msg(msg);
 385         kfree(info->node_cache);
 386         spin_unlock(&info->lock);
 387
 388         /* Total amount of bytes accounted for the mqueue */
 389         mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
 390                 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
 391                 sizeof(struct posix_msg_tree_node);
 392
 393         mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
 394                                   info->attr.mq_msgsize);
 395
 396         user = info->user;
 397         if (user) {
 398                 spin_lock(&mq_lock);
 399                 user->mq_bytes -= mq_bytes;
 400                 /*
 401                  * get_ns_from_inode() ensures that the
 402                  * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
 403                  * to which we now hold a reference, or it is NULL.
 404                  * We can't put it here under mq_lock, though.
 405                  */
 406                 if (ipc_ns)
 407                         ipc_ns->mq_queues_count--;
 408                 spin_unlock(&mq_lock);
 409                 free_uid(user);
 410         }
 411         if (ipc_ns)
 412                 put_ipc_ns(ipc_ns);
 413 }
 414
 415 static int mqueue_create(struct inode *dir, struct dentry *dentry,
 416                                 umode_t mode, bool excl)
 417 {
 418         struct inode *inode;
 419         struct mq_attr *attr = dentry->d_fsdata;
 420         int error;
 421         struct ipc_namespace *ipc_ns;
 422
 423         spin_lock(&mq_lock);
 424         ipc_ns = __get_ns_from_inode(dir);
 425         if (!ipc_ns) {
 426                 error = -EACCES;
 427                 goto out_unlock;
 428         }
 429         if (ipc_ns->mq_queues_count >= HARD_QUEUESMAX ||
 430             (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
 431              !capable(CAP_SYS_RESOURCE))) {
 432                 error = -ENOSPC;
 433                 goto out_unlock;
 434         }
 435         ipc_ns->mq_queues_count++;
 436         spin_unlock(&mq_lock);
 437
 438         inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
 439         if (IS_ERR(inode)) {
 440                 error = PTR_ERR(inode);
 441                 spin_lock(&mq_lock);
 442                 ipc_ns->mq_queues_count--;
 443                 goto out_unlock;
 444         }
 445
 446         put_ipc_ns(ipc_ns);
 447         dir->i_size += DIRENT_SIZE;
 448         dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
 449
 450         d_instantiate(dentry, inode);
 451         dget(dentry);
 452         return 0;
 453 out_unlock:
 454         spin_unlock(&mq_lock);
 455         if (ipc_ns)
 456                 put_ipc_ns(ipc_ns);
 457         return error;
 458 }
 459
 460 static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
 461 {
 462         struct inode *inode = dentry->d_inode;
 463
 464         dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
 465         dir->i_size -= DIRENT_SIZE;
 466         drop_nlink(inode);
 467         dput(dentry);
 468         return 0;
 469 }
 470
 471 /*
 472 *       This is routine for system read from queue file.
 473 *       To avoid mess with doing here some sort of mq_receive we allow
 474 *       to read only queue size & notification info (the only values
 475 *       that are interesting from user point of view and aren't accessible
 476 *       through std routines)
 477 */
 478 static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
 479                                 size_t count, loff_t *off)
 480 {
 481         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
 482         char buffer[FILENT_SIZE];
 483         ssize_t ret;
 484
 485         spin_lock(&info->lock);
 486         snprintf(buffer, sizeof(buffer),
 487                         "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
 488                         info->qsize,
 489                         info->notify_owner ? info->notify.sigev_notify : 0,
 490                         (info->notify_owner &&
 491                          info->notify.sigev_notify == SIGEV_SIGNAL) ?
 492                                 info->notify.sigev_signo : 0,
 493                         pid_vnr(info->notify_owner));
 494         spin_unlock(&info->lock);
 495         buffer[sizeof(buffer)-1] = '\0';
 496
 497         ret = simple_read_from_buffer(u_data, count, off, buffer,
 498                                 strlen(buffer));
 499         if (ret <= 0)
 500                 return ret;
 501
 502         filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME;
 503         return ret;
 504 }
 505
 506 static int mqueue_flush_file(struct file *filp, fl_owner_t id)
 507 {
 508         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
 509
 510         spin_lock(&info->lock);
 511         if (task_tgid(current) == info->notify_owner)
 512                 remove_notification(info);
 513
 514         spin_unlock(&info->lock);
 515         return 0;
 516 }
 517
 518 static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
 519 {
 520         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
 521         int retval = 0;
 522
 523         poll_wait(filp, &info->wait_q, poll_tab);
 524
 525         spin_lock(&info->lock);
 526         if (info->attr.mq_curmsgs)
 527                 retval = POLLIN | POLLRDNORM;
 528
 529         if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
 530                 retval |= POLLOUT | POLLWRNORM;
 531         spin_unlock(&info->lock);
 532
 533         return retval;
 534 }
 535
 536 /* Adds current to info->e_wait_q[sr] before element with smaller prio */
 537 static void wq_add(struct mqueue_inode_info *info, int sr,
 538                         struct ext_wait_queue *ewp)
 539 {
 540         struct ext_wait_queue *walk;
 541
 542         ewp->task = current;
 543
 544         list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
 545                 if (walk->task->static_prio <= current->static_prio) {
 546                         list_add_tail(&ewp->list, &walk->list);
 547                         return;
 548                 }
 549         }
 550         list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
 551 }
 552
 553 /*
 554  * Puts current task to sleep. Caller must hold queue lock. After return
 555  * lock isn't held.
 556  * sr: SEND or RECV
 557  */
 558 static int wq_sleep(struct mqueue_inode_info *info, int sr,
 559                     ktime_t *timeout, struct ext_wait_queue *ewp)
 560 {
 561         int retval;
 562         signed long time;
 563
 564         wq_add(info, sr, ewp);
 565
 566         for (;;) {
 567                 set_current_state(TASK_INTERRUPTIBLE);
 568
 569                 spin_unlock(&info->lock);
 570                 time = schedule_hrtimeout_range_clock(timeout, 0,
 571                         HRTIMER_MODE_ABS, CLOCK_REALTIME);
 572
 573                 while (ewp->state == STATE_PENDING)
 574                         cpu_relax();
 575
 576                 if (ewp->state == STATE_READY) {
 577                         retval = 0;
 578                         goto out;
 579                 }
 580                 spin_lock(&info->lock);
 581                 if (ewp->state == STATE_READY) {
 582                         retval = 0;
 583                         goto out_unlock;
 584                 }
 585                 if (signal_pending(current)) {
 586                         retval = -ERESTARTSYS;
 587                         break;
 588                 }
 589                 if (time == 0) {
 590                         retval = -ETIMEDOUT;
 591                         break;
 592                 }
 593         }
 594         list_del(&ewp->list);
 595 out_unlock:
 596         spin_unlock(&info->lock);
 597 out:
 598         return retval;
 599 }
 600
 601 /*
 602  * Returns waiting task that should be serviced first or NULL if none exists
 603  */
 604 static struct ext_wait_queue *wq_get_first_waiter(
 605                 struct mqueue_inode_info *info, int sr)
 606 {
 607         struct list_head *ptr;
 608
 609         ptr = info->e_wait_q[sr].list.prev;
 610         if (ptr == &info->e_wait_q[sr].list)
 611                 return NULL;
 612         return list_entry(ptr, struct ext_wait_queue, list);
 613 }
 614
 615
 616 static inline void set_cookie(struct sk_buff *skb, char code)
 617 {
 618         ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
 619 }
 620
 621 /*
 622  * The next function is only to split too long sys_mq_timedsend
 623  */
 624 static void __do_notify(struct mqueue_inode_info *info)
 625 {
 626         /* notification
 627          * invoked when there is registered process and there isn't process
 628          * waiting synchronously for message AND state of queue changed from
 629          * empty to not empty. Here we are sure that no one is waiting
 630          * synchronously. */
 631         if (info->notify_owner &&
 632             info->attr.mq_curmsgs == 1) {
 633                 struct siginfo sig_i;
 634                 switch (info->notify.sigev_notify) {
 635                 case SIGEV_NONE:
 636                         break;
 637                 case SIGEV_SIGNAL:
 638                         /* sends signal */
 639
 640                         sig_i.si_signo = info->notify.sigev_signo;
 641                         sig_i.si_errno = 0;
 642                         sig_i.si_code = SI_MESGQ;
 643                         sig_i.si_value = info->notify.sigev_value;
 644                         /* map current pid/uid into info->owner's namespaces */
 645                         rcu_read_lock();
 646                         sig_i.si_pid = task_tgid_nr_ns(current,
 647                                                 ns_of_pid(info->notify_owner));
 648                         sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
 649                         rcu_read_unlock();
 650
 651                         kill_pid_info(info->notify.sigev_signo,
 652                                       &sig_i, info->notify_owner);
 653                         break;
 654                 case SIGEV_THREAD:
 655                         set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
 656                         netlink_sendskb(info->notify_sock, info->notify_cookie);
 657                         break;
 658                 }
 659                 /* after notification unregisters process */
 660                 put_pid(info->notify_owner);
 661                 put_user_ns(info->notify_user_ns);
 662                 info->notify_owner = NULL;
 663                 info->notify_user_ns = NULL;
 664         }
 665         wake_up(&info->wait_q);
 666 }
 667
 668 static int prepare_timeout(const struct timespec __user *u_abs_timeout,
 669                            ktime_t *expires, struct timespec *ts)
 670 {
 671         if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec)))
 672                 return -EFAULT;
 673         if (!timespec_valid(ts))
 674                 return -EINVAL;
 675
 676         *expires = timespec_to_ktime(*ts);
 677         return 0;
 678 }
 679
 680 static void remove_notification(struct mqueue_inode_info *info)
 681 {
 682         if (info->notify_owner != NULL &&
 683             info->notify.sigev_notify == SIGEV_THREAD) {
 684                 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
 685                 netlink_sendskb(info->notify_sock, info->notify_cookie);
 686         }
 687         put_pid(info->notify_owner);
 688         put_user_ns(info->notify_user_ns);
 689         info->notify_owner = NULL;
 690         info->notify_user_ns = NULL;
 691 }
 692
 693 static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
 694 {
 695         int mq_treesize;
 696         unsigned long total_size;
 697
 698         if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
 699                 return -EINVAL;
 700         if (capable(CAP_SYS_RESOURCE)) {
 701                 if (attr->mq_maxmsg > HARD_MSGMAX ||
 702                     attr->mq_msgsize > HARD_MSGSIZEMAX)
 703                         return -EINVAL;
 704         } else {
 705                 if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
 706                                 attr->mq_msgsize > ipc_ns->mq_msgsize_max)
 707                         return -EINVAL;
 708         }
 709         /* check for overflow */
 710         if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
 711                 return -EOVERFLOW;
 712         mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) +
 713                 min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) *
 714                 sizeof(struct posix_msg_tree_node);
 715         total_size = attr->mq_maxmsg * attr->mq_msgsize;
 716         if (total_size + mq_treesize < total_size)
 717                 return -EOVERFLOW;
 718         return 0;
 719 }
 720
 721 /*
 722  * Invoked when creating a new queue via sys_mq_open
 723  */
 724 static struct file *do_create(struct ipc_namespace *ipc_ns, struct dentry *dir,
 725                         struct dentry *dentry, int oflag, umode_t mode,
 726                         struct mq_attr *attr)
 727 {
 728         const struct cred *cred = current_cred();
 729         struct file *result;
 730         int ret;
 731
 732         if (attr) {
 733                 ret = mq_attr_ok(ipc_ns, attr);
 734                 if (ret)
 735                         goto out;
 736                 /* store for use during create */
 737                 dentry->d_fsdata = attr;
 738         } else {
 739                 struct mq_attr def_attr;
 740
 741                 def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
 742                                          ipc_ns->mq_msg_default);
 743                 def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
 744                                           ipc_ns->mq_msgsize_default);
 745                 ret = mq_attr_ok(ipc_ns, &def_attr);
 746                 if (ret)
 747                         goto out;
 748         }
 749
 750         mode &= ~current_umask();
 751         ret = mnt_want_write(ipc_ns->mq_mnt);
 752         if (ret)
 753                 goto out;
 754         ret = vfs_create(dir->d_inode, dentry, mode, true);
 755         dentry->d_fsdata = NULL;
 756         if (ret)
 757                 goto out_drop_write;
 758
 759         result = dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
 760         /*
 761          * dentry_open() took a persistent mnt_want_write(),
 762          * so we can now drop this one.
 763          */
 764         mnt_drop_write(ipc_ns->mq_mnt);
 765         return result;
 766
 767 out_drop_write:
 768         mnt_drop_write(ipc_ns->mq_mnt);
 769 out:
 770         dput(dentry);
 771         mntput(ipc_ns->mq_mnt);
 772         return ERR_PTR(ret);
 773 }
 774
 775 /* Opens existing queue */
 776 static struct file *do_open(struct ipc_namespace *ipc_ns,
 777                                 struct dentry *dentry, int oflag)
 778 {
 779         int ret;
 780         const struct cred *cred = current_cred();
 781
 782         static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
 783                                                   MAY_READ | MAY_WRITE };
 784
 785         if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
 786                 ret = -EINVAL;
 787                 goto err;
 788         }
 789
 790         if (inode_permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE])) {
 791                 ret = -EACCES;
 792                 goto err;
 793         }
 794
 795         return dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
 796
 797 err:
 798         dput(dentry);
 799         mntput(ipc_ns->mq_mnt);
 800         return ERR_PTR(ret);
 801 }
 802
 803 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
 804                 struct mq_attr __user *, u_attr)
 805 {
 806         struct dentry *dentry;
 807         struct file *filp;
 808         char *name;
 809         struct mq_attr attr;
 810         int fd, error;
 811         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
 812
 813         if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
 814                 return -EFAULT;
 815
 816         audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
 817
 818         if (IS_ERR(name = getname(u_name)))
 819                 return PTR_ERR(name);
 820
 821         fd = get_unused_fd_flags(O_CLOEXEC);
 822         if (fd < 0)
 823                 goto out_putname;
 824
 825         mutex_lock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
 826         dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
 827         if (IS_ERR(dentry)) {
 828                 error = PTR_ERR(dentry);
 829                 goto out_putfd;
 830         }
 831         mntget(ipc_ns->mq_mnt);
 832
 833         if (oflag & O_CREAT) {
 834                 if (dentry->d_inode) {  /* entry already exists */
 835                         audit_inode(name, dentry);
 836                         if (oflag & O_EXCL) {
 837                                 error = -EEXIST;
 838                                 goto out;
 839                         }
 840                         filp = do_open(ipc_ns, dentry, oflag);
 841                 } else {
 842                         filp = do_create(ipc_ns, ipc_ns->mq_mnt->mnt_root,
 843                                                 dentry, oflag, mode,
 844                                                 u_attr ? &attr : NULL);
 845                 }
 846         } else {
 847                 if (!dentry->d_inode) {
 848                         error = -ENOENT;
 849                         goto out;
 850                 }
 851                 audit_inode(name, dentry);
 852                 filp = do_open(ipc_ns, dentry, oflag);
 853         }
 854
 855         if (IS_ERR(filp)) {
 856                 error = PTR_ERR(filp);
 857                 goto out_putfd;
 858         }
 859
 860         fd_install(fd, filp);
 861         goto out_upsem;
 862
 863 out:
 864         dput(dentry);
 865         mntput(ipc_ns->mq_mnt);
 866 out_putfd:
 867         put_unused_fd(fd);
 868         fd = error;
 869 out_upsem:
 870         mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
 871 out_putname:
 872         putname(name);
 873         return fd;
 874 }
 875
 876 SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
 877 {
 878         int err;
 879         char *name;
 880         struct dentry *dentry;
 881         struct inode *inode = NULL;
 882         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
 883
 884         name = getname(u_name);
 885         if (IS_ERR(name))
 886                 return PTR_ERR(name);
 887
 888         mutex_lock_nested(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex,
 889                         I_MUTEX_PARENT);
 890         dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
 891         if (IS_ERR(dentry)) {
 892                 err = PTR_ERR(dentry);
 893                 goto out_unlock;
 894         }
 895
 896         if (!dentry->d_inode) {
 897                 err = -ENOENT;
 898                 goto out_err;
 899         }
 900
 901         inode = dentry->d_inode;
 902         if (inode)
 903                 ihold(inode);
 904         err = mnt_want_write(ipc_ns->mq_mnt);
 905         if (err)
 906                 goto out_err;
 907         err = vfs_unlink(dentry->d_parent->d_inode, dentry);
 908         mnt_drop_write(ipc_ns->mq_mnt);
 909 out_err:
 910         dput(dentry);
 911
 912 out_unlock:
 913         mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
 914         putname(name);
 915         if (inode)
 916                 iput(inode);
 917
 918         return err;
 919 }
 920
 921 /* Pipelined send and receive functions.
 922  *
 923  * If a receiver finds no waiting message, then it registers itself in the
 924  * list of waiting receivers. A sender checks that list before adding the new
 925  * message into the message array. If there is a waiting receiver, then it
 926  * bypasses the message array and directly hands the message over to the
 927  * receiver.
 928  * The receiver accepts the message and returns without grabbing the queue
 929  * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
 930  * are necessary. The same algorithm is used for sysv semaphores, see
 931  * ipc/sem.c for more details.
 932  *
 933  * The same algorithm is used for senders.
 934  */
 935
 936 /* pipelined_send() - send a message directly to the task waiting in
 937  * sys_mq_timedreceive() (without inserting message into a queue).
 938  */
 939 static inline void pipelined_send(struct mqueue_inode_info *info,
 940                                   struct msg_msg *message,
 941                                   struct ext_wait_queue *receiver)
 942 {
 943         receiver->msg = message;
 944         list_del(&receiver->list);
 945         receiver->state = STATE_PENDING;
 946         wake_up_process(receiver->task);
 947         smp_wmb();
 948         receiver->state = STATE_READY;
 949 }
 950
 951 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
 952  * gets its message and put to the queue (we have one free place for sure). */
 953 static inline void pipelined_receive(struct mqueue_inode_info *info)
 954 {
 955         struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
 956
 957         if (!sender) {
 958                 /* for poll */
 959                 wake_up_interruptible(&info->wait_q);
 960                 return;
 961         }
 962         if (msg_insert(sender->msg, info))
 963                 return;
 964         list_del(&sender->list);
 965         sender->state = STATE_PENDING;
 966         wake_up_process(sender->task);
 967         smp_wmb();
 968         sender->state = STATE_READY;
 969 }
 970
 971 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
 972                 size_t, msg_len, unsigned int, msg_prio,
 973                 const struct timespec __user *, u_abs_timeout)
 974 {
 975         struct file *filp;
 976         struct inode *inode;
 977         struct ext_wait_queue wait;
 978         struct ext_wait_queue *receiver;
 979         struct msg_msg *msg_ptr;
 980         struct mqueue_inode_info *info;
 981         ktime_t expires, *timeout = NULL;
 982         struct timespec ts;
 983         struct posix_msg_tree_node *new_leaf = NULL;
 984         int ret = 0;
 985
 986         if (u_abs_timeout) {
 987                 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
 988                 if (res)
 989                         return res;
 990                 timeout = &expires;
 991         }
 992
 993         if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
 994                 return -EINVAL;
 995
 996         audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL);
 997
 998         filp = fget(mqdes);
 999         if (unlikely(!filp)) {
1000                 ret = -EBADF;
1001                 goto out;
1002         }
1003
1004         inode = filp->f_path.dentry->d_inode;
1005         if (unlikely(filp->f_op != &mqueue_file_operations)) {
1006                 ret = -EBADF;
1007                 goto out_fput;
1008         }
1009         info = MQUEUE_I(inode);
1010         audit_inode(NULL, filp->f_path.dentry);
1011
1012         if (unlikely(!(filp->f_mode & FMODE_WRITE))) {
1013                 ret = -EBADF;
1014                 goto out_fput;
1015         }
1016
1017         if (unlikely(msg_len > info->attr.mq_msgsize)) {
1018                 ret = -EMSGSIZE;
1019                 goto out_fput;
1020         }
1021
1022         /* First try to allocate memory, before doing anything with
1023          * existing queues. */
1024         msg_ptr = load_msg(u_msg_ptr, msg_len);
1025         if (IS_ERR(msg_ptr)) {
1026                 ret = PTR_ERR(msg_ptr);
1027                 goto out_fput;
1028         }
1029         msg_ptr->m_ts = msg_len;
1030         msg_ptr->m_type = msg_prio;
1031
1032         /*
1033          * msg_insert really wants us to have a valid, spare node struct so
1034          * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1035          * fall back to that if necessary.
1036          */
1037         if (!info->node_cache)
1038                 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1039
1040         spin_lock(&info->lock);
1041
1042         if (!info->node_cache && new_leaf) {
1043                 /* Save our speculative allocation into the cache */
1044                 rb_init_node(&new_leaf->rb_node);
1045                 INIT_LIST_HEAD(&new_leaf->msg_list);
1046                 info->node_cache = new_leaf;
1047                 info->qsize += sizeof(*new_leaf);
1048                 new_leaf = NULL;
1049         } else {
1050                 kfree(new_leaf);
1051         }
1052
1053         if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1054                 if (filp->f_flags & O_NONBLOCK) {
1055                         ret = -EAGAIN;
1056                 } else {
1057                         wait.task = current;
1058                         wait.msg = (void *) msg_ptr;
1059                         wait.state = STATE_NONE;
1060                         ret = wq_sleep(info, SEND, timeout, &wait);
1061                         /*
1062                          * wq_sleep must be called with info->lock held, and
1063                          * returns with the lock released
1064                          */
1065                         goto out_free;
1066                 }
1067         } else {
1068                 receiver = wq_get_first_waiter(info, RECV);
1069                 if (receiver) {
1070                         pipelined_send(info, msg_ptr, receiver);
1071                 } else {
1072                         /* adds message to the queue */
1073                         ret = msg_insert(msg_ptr, info);
1074                         if (ret)
1075                                 goto out_unlock;
1076                         __do_notify(info);
1077                 }
1078                 inode->i_atime = inode->i_mtime = inode->i_ctime =
1079                                 CURRENT_TIME;
1080         }
1081 out_unlock:
1082         spin_unlock(&info->lock);
1083 out_free:
1084         if (ret)
1085                 free_msg(msg_ptr);
1086 out_fput:
1087         fput(filp);
1088 out:
1089         return ret;
1090 }
1091
1092 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1093                 size_t, msg_len, unsigned int __user *, u_msg_prio,
1094                 const struct timespec __user *, u_abs_timeout)
1095 {
1096         ssize_t ret;
1097         struct msg_msg *msg_ptr;
1098         struct file *filp;
1099         struct inode *inode;
1100         struct mqueue_inode_info *info;
1101         struct ext_wait_queue wait;
1102         ktime_t expires, *timeout = NULL;
1103         struct timespec ts;
1104         struct posix_msg_tree_node *new_leaf = NULL;
1105
1106         if (u_abs_timeout) {
1107                 int res = prepare_timeout(u_abs_timeout, &expires, &ts);
1108                 if (res)
1109                         return res;
1110                 timeout = &expires;
1111         }
1112
1113         audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL);
1114
1115         filp = fget(mqdes);
1116         if (unlikely(!filp)) {
1117                 ret = -EBADF;
1118                 goto out;
1119         }
1120
1121         inode = filp->f_path.dentry->d_inode;
1122         if (unlikely(filp->f_op != &mqueue_file_operations)) {
1123                 ret = -EBADF;
1124                 goto out_fput;
1125         }
1126         info = MQUEUE_I(inode);
1127         audit_inode(NULL, filp->f_path.dentry);
1128
1129         if (unlikely(!(filp->f_mode & FMODE_READ))) {
1130                 ret = -EBADF;
1131                 goto out_fput;
1132         }
1133
1134         /* checks if buffer is big enough */
1135         if (unlikely(msg_len < info->attr.mq_msgsize)) {
1136                 ret = -EMSGSIZE;
1137                 goto out_fput;
1138         }
1139
1140         /*
1141          * msg_insert really wants us to have a valid, spare node struct so
1142          * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1143          * fall back to that if necessary.
1144          */
1145         if (!info->node_cache)
1146                 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1147
1148         spin_lock(&info->lock);
1149
1150         if (!info->node_cache && new_leaf) {
1151                 /* Save our speculative allocation into the cache */
1152                 rb_init_node(&new_leaf->rb_node);
1153                 INIT_LIST_HEAD(&new_leaf->msg_list);
1154                 info->node_cache = new_leaf;
1155                 info->qsize += sizeof(*new_leaf);
1156         } else {
1157                 kfree(new_leaf);
1158         }
1159
1160         if (info->attr.mq_curmsgs == 0) {
1161                 if (filp->f_flags & O_NONBLOCK) {
1162                         spin_unlock(&info->lock);
1163                         ret = -EAGAIN;
1164                 } else {
1165                         wait.task = current;
1166                         wait.state = STATE_NONE;
1167                         ret = wq_sleep(info, RECV, timeout, &wait);
1168                         msg_ptr = wait.msg;
1169                 }
1170         } else {
1171                 msg_ptr = msg_get(info);
1172
1173                 inode->i_atime = inode->i_mtime = inode->i_ctime =
1174                                 CURRENT_TIME;
1175
1176                 /* There is now free space in queue. */
1177                 pipelined_receive(info);
1178                 spin_unlock(&info->lock);
1179                 ret = 0;
1180         }
1181         if (ret == 0) {
1182                 ret = msg_ptr->m_ts;
1183
1184                 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1185                         store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1186                         ret = -EFAULT;
1187                 }
1188                 free_msg(msg_ptr);
1189         }
1190 out_fput:
1191         fput(filp);
1192 out:
1193         return ret;
1194 }
1195
1196 /*
1197  * Notes: the case when user wants us to deregister (with NULL as pointer)
1198  * and he isn't currently owner of notification, will be silently discarded.
1199  * It isn't explicitly defined in the POSIX.
1200  */
1201 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1202                 const struct sigevent __user *, u_notification)
1203 {
1204         int ret;
1205         struct file *filp;
1206         struct sock *sock;
1207         struct inode *inode;
1208         struct sigevent notification;
1209         struct mqueue_inode_info *info;
1210         struct sk_buff *nc;
1211
1212         if (u_notification) {
1213                 if (copy_from_user(&notification, u_notification,
1214                                         sizeof(struct sigevent)))
1215                         return -EFAULT;
1216         }
1217
1218         audit_mq_notify(mqdes, u_notification ? &notification : NULL);
1219
1220         nc = NULL;
1221         sock = NULL;
1222         if (u_notification != NULL) {
1223                 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1224                              notification.sigev_notify != SIGEV_SIGNAL &&
1225                              notification.sigev_notify != SIGEV_THREAD))
1226                         return -EINVAL;
1227                 if (notification.sigev_notify == SIGEV_SIGNAL &&
1228                         !valid_signal(notification.sigev_signo)) {
1229                         return -EINVAL;
1230                 }
1231                 if (notification.sigev_notify == SIGEV_THREAD) {
1232                         long timeo;
1233
1234                         /* create the notify skb */
1235                         nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1236                         if (!nc) {
1237                                 ret = -ENOMEM;
1238                                 goto out;
1239                         }
1240                         if (copy_from_user(nc->data,
1241                                         notification.sigev_value.sival_ptr,
1242                                         NOTIFY_COOKIE_LEN)) {
1243                                 ret = -EFAULT;
1244                                 goto out;
1245                         }
1246
1247                         /* TODO: add a header? */
1248                         skb_put(nc, NOTIFY_COOKIE_LEN);
1249                         /* and attach it to the socket */
1250 retry:
1251                         filp = fget(notification.sigev_signo);
1252                         if (!filp) {
1253                                 ret = -EBADF;
1254                                 goto out;
1255                         }
1256                         sock = netlink_getsockbyfilp(filp);
1257                         fput(filp);
1258                         if (IS_ERR(sock)) {
1259                                 ret = PTR_ERR(sock);
1260                                 sock = NULL;
1261                                 goto out;
1262                         }
1263
1264                         timeo = MAX_SCHEDULE_TIMEOUT;
1265                         ret = netlink_attachskb(sock, nc, &timeo, NULL);
1266                         if (ret == 1)
1267                                 goto retry;
1268                         if (ret) {
1269                                 sock = NULL;
1270                                 nc = NULL;
1271                                 goto out;
1272                         }
1273                 }
1274         }
1275
1276         filp = fget(mqdes);
1277         if (!filp) {
1278                 ret = -EBADF;
1279                 goto out;
1280         }
1281
1282         inode = filp->f_path.dentry->d_inode;
1283         if (unlikely(filp->f_op != &mqueue_file_operations)) {
1284                 ret = -EBADF;
1285                 goto out_fput;
1286         }
1287         info = MQUEUE_I(inode);
1288
1289         ret = 0;
1290         spin_lock(&info->lock);
1291         if (u_notification == NULL) {
1292                 if (info->notify_owner == task_tgid(current)) {
1293                         remove_notification(info);
1294                         inode->i_atime = inode->i_ctime = CURRENT_TIME;
1295                 }
1296         } else if (info->notify_owner != NULL) {
1297                 ret = -EBUSY;
1298         } else {
1299                 switch (notification.sigev_notify) {
1300                 case SIGEV_NONE:
1301                         info->notify.sigev_notify = SIGEV_NONE;
1302                         break;
1303                 case SIGEV_THREAD:
1304                         info->notify_sock = sock;
1305                         info->notify_cookie = nc;
1306                         sock = NULL;
1307                         nc = NULL;
1308                         info->notify.sigev_notify = SIGEV_THREAD;
1309                         break;
1310                 case SIGEV_SIGNAL:
1311                         info->notify.sigev_signo = notification.sigev_signo;
1312                         info->notify.sigev_value = notification.sigev_value;
1313                         info->notify.sigev_notify = SIGEV_SIGNAL;
1314                         break;
1315                 }
1316
1317                 info->notify_owner = get_pid(task_tgid(current));
1318                 info->notify_user_ns = get_user_ns(current_user_ns());
1319                 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1320         }
1321         spin_unlock(&info->lock);
1322 out_fput:
1323         fput(filp);
1324 out:
1325         if (sock) {
1326                 netlink_detachskb(sock, nc);
1327         } else if (nc) {
1328                 dev_kfree_skb(nc);
1329         }
1330         return ret;
1331 }
1332
1333 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1334                 const struct mq_attr __user *, u_mqstat,
1335                 struct mq_attr __user *, u_omqstat)
1336 {
1337         int ret;
1338         struct mq_attr mqstat, omqstat;
1339         struct file *filp;
1340         struct inode *inode;
1341         struct mqueue_inode_info *info;
1342
1343         if (u_mqstat != NULL) {
1344                 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1345                         return -EFAULT;
1346                 if (mqstat.mq_flags & (~O_NONBLOCK))
1347                         return -EINVAL;
1348         }
1349
1350         filp = fget(mqdes);
1351         if (!filp) {
1352                 ret = -EBADF;
1353                 goto out;
1354         }
1355
1356         inode = filp->f_path.dentry->d_inode;
1357         if (unlikely(filp->f_op != &mqueue_file_operations)) {
1358                 ret = -EBADF;
1359                 goto out_fput;
1360         }
1361         info = MQUEUE_I(inode);
1362
1363         spin_lock(&info->lock);
1364
1365         omqstat = info->attr;
1366         omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
1367         if (u_mqstat) {
1368                 audit_mq_getsetattr(mqdes, &mqstat);
1369                 spin_lock(&filp->f_lock);
1370                 if (mqstat.mq_flags & O_NONBLOCK)
1371                         filp->f_flags |= O_NONBLOCK;
1372                 else
1373                         filp->f_flags &= ~O_NONBLOCK;
1374                 spin_unlock(&filp->f_lock);
1375
1376                 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1377         }
1378
1379         spin_unlock(&info->lock);
1380
1381         ret = 0;
1382         if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1383                                                 sizeof(struct mq_attr)))
1384                 ret = -EFAULT;
1385
1386 out_fput:
1387         fput(filp);
1388 out:
1389         return ret;
1390 }
1391
1392 static const struct inode_operations mqueue_dir_inode_operations = {
1393         .lookup = simple_lookup,
1394         .create = mqueue_create,
1395         .unlink = mqueue_unlink,
1396 };
1397
1398 static const struct file_operations mqueue_file_operations = {
1399         .flush = mqueue_flush_file,
1400         .poll = mqueue_poll_file,
1401         .read = mqueue_read_file,
1402         .llseek = default_llseek,
1403 };
1404
1405 static const struct super_operations mqueue_super_ops = {
1406         .alloc_inode = mqueue_alloc_inode,
1407         .destroy_inode = mqueue_destroy_inode,
1408         .evict_inode = mqueue_evict_inode,
1409         .statfs = simple_statfs,
1410 };
1411
1412 static struct file_system_type mqueue_fs_type = {
1413         .name = "mqueue",
1414         .mount = mqueue_mount,
1415         .kill_sb = kill_litter_super,
1416 };
1417
1418 int mq_init_ns(struct ipc_namespace *ns)
1419 {
1420         ns->mq_queues_count  = 0;
1421         ns->mq_queues_max    = DFLT_QUEUESMAX;
1422         ns->mq_msg_max       = DFLT_MSGMAX;
1423         ns->mq_msgsize_max   = DFLT_MSGSIZEMAX;
1424         ns->mq_msg_default   = DFLT_MSG;
1425         ns->mq_msgsize_default  = DFLT_MSGSIZE;
1426
1427         ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1428         if (IS_ERR(ns->mq_mnt)) {
1429                 int err = PTR_ERR(ns->mq_mnt);
1430                 ns->mq_mnt = NULL;
1431                 return err;
1432         }
1433         return 0;
1434 }
1435
1436 void mq_clear_sbinfo(struct ipc_namespace *ns)
1437 {
1438         ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1439 }
1440
1441 void mq_put_mnt(struct ipc_namespace *ns)
1442 {
1443         kern_unmount(ns->mq_mnt);
1444 }
1445
1446 static int __init init_mqueue_fs(void)
1447 {
1448         int error;
1449
1450         mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1451                                 sizeof(struct mqueue_inode_info), 0,
1452                                 SLAB_HWCACHE_ALIGN, init_once);
1453         if (mqueue_inode_cachep == NULL)
1454                 return -ENOMEM;
1455
1456         /* ignore failures - they are not fatal */
1457         mq_sysctl_table = mq_register_sysctl_table();
1458
1459         error = register_filesystem(&mqueue_fs_type);
1460         if (error)
1461                 goto out_sysctl;
1462
1463         spin_lock_init(&mq_lock);
1464
1465         error = mq_init_ns(&init_ipc_ns);
1466         if (error)
1467                 goto out_filesystem;
1468
1469         return 0;
1470
1471 out_filesystem:
1472         unregister_filesystem(&mqueue_fs_type);
1473 out_sysctl:
1474         if (mq_sysctl_table)
1475                 unregister_sysctl_table(mq_sysctl_table);
1476         kmem_cache_destroy(mqueue_inode_cachep);
1477         return error;
1478 }
1479
1480 __initcall(init_mqueue_fs);