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