linux/ipc/mqueue.c
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   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
  53struct posix_msg_tree_node {
  54        struct rb_node          rb_node;
  55        struct list_head        msg_list;
  56        int                     priority;
  57};
  58
  59struct 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
  66struct 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
  88static const struct inode_operations mqueue_dir_inode_operations;
  89static const struct file_operations mqueue_file_operations;
  90static const struct super_operations mqueue_super_ops;
  91static void remove_notification(struct mqueue_inode_info *info);
  92
  93static struct kmem_cache *mqueue_inode_cachep;
  94
  95static struct ctl_table_header * mq_sysctl_table;
  96
  97static 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 */
 105static 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
 110static 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 */
 121static 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);
 151insert_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
 158static 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
 164try_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
 216static 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;
 303out_inode:
 304        iput(inode);
 305err:
 306        return ERR_PTR(ret);
 307}
 308
 309static 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
 329static 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                data = current->nsproxy->ipc_ns;
 335        return mount_ns(fs_type, flags, data, mqueue_fill_super);
 336}
 337
 338static void init_once(void *foo)
 339{
 340        struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
 341
 342        inode_init_once(&p->vfs_inode);
 343}
 344
 345static struct inode *mqueue_alloc_inode(struct super_block *sb)
 346{
 347        struct mqueue_inode_info *ei;
 348
 349        ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
 350        if (!ei)
 351                return NULL;
 352        return &ei->vfs_inode;
 353}
 354
 355static void mqueue_i_callback(struct rcu_head *head)
 356{
 357        struct inode *inode = container_of(head, struct inode, i_rcu);
 358        kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
 359}
 360
 361static void mqueue_destroy_inode(struct inode *inode)
 362{
 363        call_rcu(&inode->i_rcu, mqueue_i_callback);
 364}
 365
 366static void mqueue_evict_inode(struct inode *inode)
 367{
 368        struct mqueue_inode_info *info;
 369        struct user_struct *user;
 370        unsigned long mq_bytes, mq_treesize;
 371        struct ipc_namespace *ipc_ns;
 372        struct msg_msg *msg;
 373
 374        clear_inode(inode);
 375
 376        if (S_ISDIR(inode->i_mode))
 377                return;
 378
 379        ipc_ns = get_ns_from_inode(inode);
 380        info = MQUEUE_I(inode);
 381        spin_lock(&info->lock);
 382        while ((msg = msg_get(info)) != NULL)
 383                free_msg(msg);
 384        kfree(info->node_cache);
 385        spin_unlock(&info->lock);
 386
 387        /* Total amount of bytes accounted for the mqueue */
 388        mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
 389                min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
 390                sizeof(struct posix_msg_tree_node);
 391
 392        mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
 393                                  info->attr.mq_msgsize);
 394
 395        user = info->user;
 396        if (user) {
 397                spin_lock(&mq_lock);
 398                user->mq_bytes -= mq_bytes;
 399                /*
 400                 * get_ns_from_inode() ensures that the
 401                 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
 402                 * to which we now hold a reference, or it is NULL.
 403                 * We can't put it here under mq_lock, though.
 404                 */
 405                if (ipc_ns)
 406                        ipc_ns->mq_queues_count--;
 407                spin_unlock(&mq_lock);
 408                free_uid(user);
 409        }
 410        if (ipc_ns)
 411                put_ipc_ns(ipc_ns);
 412}
 413
 414static int mqueue_create(struct inode *dir, struct dentry *dentry,
 415                                umode_t mode, bool excl)
 416{
 417        struct inode *inode;
 418        struct mq_attr *attr = dentry->d_fsdata;
 419        int error;
 420        struct ipc_namespace *ipc_ns;
 421
 422        spin_lock(&mq_lock);
 423        ipc_ns = __get_ns_from_inode(dir);
 424        if (!ipc_ns) {
 425                error = -EACCES;
 426                goto out_unlock;
 427        }
 428        if (ipc_ns->mq_queues_count >= HARD_QUEUESMAX ||
 429            (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
 430             !capable(CAP_SYS_RESOURCE))) {
 431                error = -ENOSPC;
 432                goto out_unlock;
 433        }
 434        ipc_ns->mq_queues_count++;
 435        spin_unlock(&mq_lock);
 436
 437        inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
 438        if (IS_ERR(inode)) {
 439                error = PTR_ERR(inode);
 440                spin_lock(&mq_lock);
 441                ipc_ns->mq_queues_count--;
 442                goto out_unlock;
 443        }
 444
 445        put_ipc_ns(ipc_ns);
 446        dir->i_size += DIRENT_SIZE;
 447        dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
 448
 449        d_instantiate(dentry, inode);
 450        dget(dentry);
 451        return 0;
 452out_unlock:
 453        spin_unlock(&mq_lock);
 454        if (ipc_ns)
 455                put_ipc_ns(ipc_ns);
 456        return error;
 457}
 458
 459static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
 460{
 461        struct inode *inode = dentry->d_inode;
 462
 463        dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
 464        dir->i_size -= DIRENT_SIZE;
 465        drop_nlink(inode);
 466        dput(dentry);
 467        return 0;
 468}
 469
 470/*
 471*       This is routine for system read from queue file.
 472*       To avoid mess with doing here some sort of mq_receive we allow
 473*       to read only queue size & notification info (the only values
 474*       that are interesting from user point of view and aren't accessible
 475*       through std routines)
 476*/
 477static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
 478                                size_t count, loff_t *off)
 479{
 480        struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
 481        char buffer[FILENT_SIZE];
 482        ssize_t ret;
 483
 484        spin_lock(&info->lock);
 485        snprintf(buffer, sizeof(buffer),
 486                        "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
 487                        info->qsize,
 488                        info->notify_owner ? info->notify.sigev_notify : 0,
 489                        (info->notify_owner &&
 490                         info->notify.sigev_notify == SIGEV_SIGNAL) ?
 491                                info->notify.sigev_signo : 0,
 492                        pid_vnr(info->notify_owner));
 493        spin_unlock(&info->lock);
 494        buffer[sizeof(buffer)-1] = '\0';
 495
 496        ret = simple_read_from_buffer(u_data, count, off, buffer,
 497                                strlen(buffer));
 498        if (ret <= 0)
 499                return ret;
 500
 501        filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME;
 502        return ret;
 503}
 504
 505static int mqueue_flush_file(struct file *filp, fl_owner_t id)
 506{
 507        struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
 508
 509        spin_lock(&info->lock);
 510        if (task_tgid(current) == info->notify_owner)
 511                remove_notification(info);
 512
 513        spin_unlock(&info->lock);
 514        return 0;
 515}
 516
 517static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
 518{
 519        struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
 520        int retval = 0;
 521
 522        poll_wait(filp, &info->wait_q, poll_tab);
 523
 524        spin_lock(&info->lock);
 525        if (info->attr.mq_curmsgs)
 526                retval = POLLIN | POLLRDNORM;
 527
 528        if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
 529                retval |= POLLOUT | POLLWRNORM;
 530        spin_unlock(&info->lock);
 531
 532        return retval;
 533}
 534
 535/* Adds current to info->e_wait_q[sr] before element with smaller prio */
 536static void wq_add(struct mqueue_inode_info *info, int sr,
 537                        struct ext_wait_queue *ewp)
 538{
 539        struct ext_wait_queue *walk;
 540
 541        ewp->task = current;
 542
 543        list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
 544                if (walk->task->static_prio <= current->static_prio) {
 545                        list_add_tail(&ewp->list, &walk->list);
 546                        return;
 547                }
 548        }
 549        list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
 550}
 551
 552/*
 553 * Puts current task to sleep. Caller must hold queue lock. After return
 554 * lock isn't held.
 555 * sr: SEND or RECV
 556 */
 557static int wq_sleep(struct mqueue_inode_info *info, int sr,
 558                    ktime_t *timeout, struct ext_wait_queue *ewp)
 559{
 560        int retval;
 561        signed long time;
 562
 563        wq_add(info, sr, ewp);
 564
 565        for (;;) {
 566                set_current_state(TASK_INTERRUPTIBLE);
 567
 568                spin_unlock(&info->lock);
 569                time = schedule_hrtimeout_range_clock(timeout, 0,
 570                        HRTIMER_MODE_ABS, CLOCK_REALTIME);
 571
 572                while (ewp->state == STATE_PENDING)
 573                        cpu_relax();
 574
 575                if (ewp->state == STATE_READY) {
 576                        retval = 0;
 577                        goto out;
 578                }
 579                spin_lock(&info->lock);
 580                if (ewp->state == STATE_READY) {
 581                        retval = 0;
 582                        goto out_unlock;
 583                }
 584                if (signal_pending(current)) {
 585                        retval = -ERESTARTSYS;
 586                        break;
 587                }
 588                if (time == 0) {
 589                        retval = -ETIMEDOUT;
 590                        break;
 591                }
 592        }
 593        list_del(&ewp->list);
 594out_unlock:
 595        spin_unlock(&info->lock);
 596out:
 597        return retval;
 598}
 599
 600/*
 601 * Returns waiting task that should be serviced first or NULL if none exists
 602 */
 603static struct ext_wait_queue *wq_get_first_waiter(
 604                struct mqueue_inode_info *info, int sr)
 605{
 606        struct list_head *ptr;
 607
 608        ptr = info->e_wait_q[sr].list.prev;
 609        if (ptr == &info->e_wait_q[sr].list)
 610                return NULL;
 611        return list_entry(ptr, struct ext_wait_queue, list);
 612}
 613
 614
 615static inline void set_cookie(struct sk_buff *skb, char code)
 616{
 617        ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
 618}
 619
 620/*
 621 * The next function is only to split too long sys_mq_timedsend
 622 */
 623static void __do_notify(struct mqueue_inode_info *info)
 624{
 625        /* notification
 626         * invoked when there is registered process and there isn't process
 627         * waiting synchronously for message AND state of queue changed from
 628         * empty to not empty. Here we are sure that no one is waiting
 629         * synchronously. */
 630        if (info->notify_owner &&
 631            info->attr.mq_curmsgs == 1) {
 632                struct siginfo sig_i;
 633                switch (info->notify.sigev_notify) {
 634                case SIGEV_NONE:
 635                        break;
 636                case SIGEV_SIGNAL:
 637                        /* sends signal */
 638
 639                        sig_i.si_signo = info->notify.sigev_signo;
 640                        sig_i.si_errno = 0;
 641                        sig_i.si_code = SI_MESGQ;
 642                        sig_i.si_value = info->notify.sigev_value;
 643                        /* map current pid/uid into info->owner's namespaces */
 644                        rcu_read_lock();
 645                        sig_i.si_pid = task_tgid_nr_ns(current,
 646                                                ns_of_pid(info->notify_owner));
 647                        sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
 648                        rcu_read_unlock();
 649
 650                        kill_pid_info(info->notify.sigev_signo,
 651                                      &sig_i, info->notify_owner);
 652                        break;
 653                case SIGEV_THREAD:
 654                        set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
 655                        netlink_sendskb(info->notify_sock, info->notify_cookie);
 656                        break;
 657                }
 658                /* after notification unregisters process */
 659                put_pid(info->notify_owner);
 660                put_user_ns(info->notify_user_ns);
 661                info->notify_owner = NULL;
 662                info->notify_user_ns = NULL;
 663        }
 664        wake_up(&info->wait_q);
 665}
 666
 667static int prepare_timeout(const struct timespec __user *u_abs_timeout,
 668                           ktime_t *expires, struct timespec *ts)
 669{
 670        if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec)))
 671                return -EFAULT;
 672        if (!timespec_valid(ts))
 673                return -EINVAL;
 674
 675        *expires = timespec_to_ktime(*ts);
 676        return 0;
 677}
 678
 679static void remove_notification(struct mqueue_inode_info *info)
 680{
 681        if (info->notify_owner != NULL &&
 682            info->notify.sigev_notify == SIGEV_THREAD) {
 683                set_cookie(info->notify_cookie, NOTIFY_REMOVED);
 684                netlink_sendskb(info->notify_sock, info->notify_cookie);
 685        }
 686        put_pid(info->notify_owner);
 687        put_user_ns(info->notify_user_ns);
 688        info->notify_owner = NULL;
 689        info->notify_user_ns = NULL;
 690}
 691
 692static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
 693{
 694        int mq_treesize;
 695        unsigned long total_size;
 696
 697        if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
 698                return -EINVAL;
 699        if (capable(CAP_SYS_RESOURCE)) {
 700                if (attr->mq_maxmsg > HARD_MSGMAX ||
 701                    attr->mq_msgsize > HARD_MSGSIZEMAX)
 702                        return -EINVAL;
 703        } else {
 704                if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
 705                                attr->mq_msgsize > ipc_ns->mq_msgsize_max)
 706                        return -EINVAL;
 707        }
 708        /* check for overflow */
 709        if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
 710                return -EOVERFLOW;
 711        mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) +
 712                min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) *
 713                sizeof(struct posix_msg_tree_node);
 714        total_size = attr->mq_maxmsg * attr->mq_msgsize;
 715        if (total_size + mq_treesize < total_size)
 716                return -EOVERFLOW;
 717        return 0;
 718}
 719
 720/*
 721 * Invoked when creating a new queue via sys_mq_open
 722 */
 723static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir,
 724                        struct path *path, int oflag, umode_t mode,
 725                        struct mq_attr *attr)
 726{
 727        const struct cred *cred = current_cred();
 728        int ret;
 729
 730        if (attr) {
 731                ret = mq_attr_ok(ipc_ns, attr);
 732                if (ret)
 733                        return ERR_PTR(ret);
 734                /* store for use during create */
 735                path->dentry->d_fsdata = attr;
 736        } else {
 737                struct mq_attr def_attr;
 738
 739                def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
 740                                         ipc_ns->mq_msg_default);
 741                def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
 742                                          ipc_ns->mq_msgsize_default);
 743                ret = mq_attr_ok(ipc_ns, &def_attr);
 744                if (ret)
 745                        return ERR_PTR(ret);
 746        }
 747
 748        mode &= ~current_umask();
 749        ret = vfs_create(dir, path->dentry, mode, true);
 750        path->dentry->d_fsdata = NULL;
 751        if (ret)
 752                return ERR_PTR(ret);
 753        return dentry_open(path, oflag, cred);
 754}
 755
 756/* Opens existing queue */
 757static struct file *do_open(struct path *path, int oflag)
 758{
 759        static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
 760                                                  MAY_READ | MAY_WRITE };
 761        int acc;
 762        if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
 763                return ERR_PTR(-EINVAL);
 764        acc = oflag2acc[oflag & O_ACCMODE];
 765        if (inode_permission(path->dentry->d_inode, acc))
 766                return ERR_PTR(-EACCES);
 767        return dentry_open(path, oflag, current_cred());
 768}
 769
 770SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
 771                struct mq_attr __user *, u_attr)
 772{
 773        struct path path;
 774        struct file *filp;
 775        struct filename *name;
 776        struct mq_attr attr;
 777        int fd, error;
 778        struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
 779        struct vfsmount *mnt = ipc_ns->mq_mnt;
 780        struct dentry *root = mnt->mnt_root;
 781        int ro;
 782
 783        if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
 784                return -EFAULT;
 785
 786        audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
 787
 788        if (IS_ERR(name = getname(u_name)))
 789                return PTR_ERR(name);
 790
 791        fd = get_unused_fd_flags(O_CLOEXEC);
 792        if (fd < 0)
 793                goto out_putname;
 794
 795        ro = mnt_want_write(mnt);       /* we'll drop it in any case */
 796        error = 0;
 797        mutex_lock(&root->d_inode->i_mutex);
 798        path.dentry = lookup_one_len(name->name, root, strlen(name->name));
 799        if (IS_ERR(path.dentry)) {
 800                error = PTR_ERR(path.dentry);
 801                goto out_putfd;
 802        }
 803        path.mnt = mntget(mnt);
 804
 805        if (oflag & O_CREAT) {
 806                if (path.dentry->d_inode) {     /* entry already exists */
 807                        audit_inode(name, path.dentry, 0);
 808                        if (oflag & O_EXCL) {
 809                                error = -EEXIST;
 810                                goto out;
 811                        }
 812                        filp = do_open(&path, oflag);
 813                } else {
 814                        if (ro) {
 815                                error = ro;
 816                                goto out;
 817                        }
 818                        filp = do_create(ipc_ns, root->d_inode,
 819                                                &path, oflag, mode,
 820                                                u_attr ? &attr : NULL);
 821                }
 822        } else {
 823                if (!path.dentry->d_inode) {
 824                        error = -ENOENT;
 825                        goto out;
 826                }
 827                audit_inode(name, path.dentry, 0);
 828                filp = do_open(&path, oflag);
 829        }
 830
 831        if (!IS_ERR(filp))
 832                fd_install(fd, filp);
 833        else
 834                error = PTR_ERR(filp);
 835out:
 836        path_put(&path);
 837out_putfd:
 838        if (error) {
 839                put_unused_fd(fd);
 840                fd = error;
 841        }
 842        mutex_unlock(&root->d_inode->i_mutex);
 843        if (!ro)
 844                mnt_drop_write(mnt);
 845out_putname:
 846        putname(name);
 847        return fd;
 848}
 849
 850SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
 851{
 852        int err;
 853        struct filename *name;
 854        struct dentry *dentry;
 855        struct inode *inode = NULL;
 856        struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
 857        struct vfsmount *mnt = ipc_ns->mq_mnt;
 858
 859        name = getname(u_name);
 860        if (IS_ERR(name))
 861                return PTR_ERR(name);
 862
 863        err = mnt_want_write(mnt);
 864        if (err)
 865                goto out_name;
 866        mutex_lock_nested(&mnt->mnt_root->d_inode->i_mutex, I_MUTEX_PARENT);
 867        dentry = lookup_one_len(name->name, mnt->mnt_root,
 868                                strlen(name->name));
 869        if (IS_ERR(dentry)) {
 870                err = PTR_ERR(dentry);
 871                goto out_unlock;
 872        }
 873
 874        inode = dentry->d_inode;
 875        if (!inode) {
 876                err = -ENOENT;
 877        } else {
 878                ihold(inode);
 879                err = vfs_unlink(dentry->d_parent->d_inode, dentry);
 880        }
 881        dput(dentry);
 882
 883out_unlock:
 884        mutex_unlock(&mnt->mnt_root->d_inode->i_mutex);
 885        if (inode)
 886                iput(inode);
 887        mnt_drop_write(mnt);
 888out_name:
 889        putname(name);
 890
 891        return err;
 892}
 893
 894/* Pipelined send and receive functions.
 895 *
 896 * If a receiver finds no waiting message, then it registers itself in the
 897 * list of waiting receivers. A sender checks that list before adding the new
 898 * message into the message array. If there is a waiting receiver, then it
 899 * bypasses the message array and directly hands the message over to the
 900 * receiver.
 901 * The receiver accepts the message and returns without grabbing the queue
 902 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
 903 * are necessary. The same algorithm is used for sysv semaphores, see
 904 * ipc/sem.c for more details.
 905 *
 906 * The same algorithm is used for senders.
 907 */
 908
 909/* pipelined_send() - send a message directly to the task waiting in
 910 * sys_mq_timedreceive() (without inserting message into a queue).
 911 */
 912static inline void pipelined_send(struct mqueue_inode_info *info,
 913                                  struct msg_msg *message,
 914                                  struct ext_wait_queue *receiver)
 915{
 916        receiver->msg = message;
 917        list_del(&receiver->list);
 918        receiver->state = STATE_PENDING;
 919        wake_up_process(receiver->task);
 920        smp_wmb();
 921        receiver->state = STATE_READY;
 922}
 923
 924/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
 925 * gets its message and put to the queue (we have one free place for sure). */
 926static inline void pipelined_receive(struct mqueue_inode_info *info)
 927{
 928        struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
 929
 930        if (!sender) {
 931                /* for poll */
 932                wake_up_interruptible(&info->wait_q);
 933                return;
 934        }
 935        if (msg_insert(sender->msg, info))
 936                return;
 937        list_del(&sender->list);
 938        sender->state = STATE_PENDING;
 939        wake_up_process(sender->task);
 940        smp_wmb();
 941        sender->state = STATE_READY;
 942}
 943
 944SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
 945                size_t, msg_len, unsigned int, msg_prio,
 946                const struct timespec __user *, u_abs_timeout)
 947{
 948        struct fd f;
 949        struct inode *inode;
 950        struct ext_wait_queue wait;
 951        struct ext_wait_queue *receiver;
 952        struct msg_msg *msg_ptr;
 953        struct mqueue_inode_info *info;
 954        ktime_t expires, *timeout = NULL;
 955        struct timespec ts;
 956        struct posix_msg_tree_node *new_leaf = NULL;
 957        int ret = 0;
 958
 959        if (u_abs_timeout) {
 960                int res = prepare_timeout(u_abs_timeout, &expires, &ts);
 961                if (res)
 962                        return res;
 963                timeout = &expires;
 964        }
 965
 966        if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
 967                return -EINVAL;
 968
 969        audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL);
 970
 971        f = fdget(mqdes);
 972        if (unlikely(!f.file)) {
 973                ret = -EBADF;
 974                goto out;
 975        }
 976
 977        inode = f.file->f_path.dentry->d_inode;
 978        if (unlikely(f.file->f_op != &mqueue_file_operations)) {
 979                ret = -EBADF;
 980                goto out_fput;
 981        }
 982        info = MQUEUE_I(inode);
 983        audit_inode(NULL, f.file->f_path.dentry, 0);
 984
 985        if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
 986                ret = -EBADF;
 987                goto out_fput;
 988        }
 989
 990        if (unlikely(msg_len > info->attr.mq_msgsize)) {
 991                ret = -EMSGSIZE;
 992                goto out_fput;
 993        }
 994
 995        /* First try to allocate memory, before doing anything with
 996         * existing queues. */
 997        msg_ptr = load_msg(u_msg_ptr, msg_len);
 998        if (IS_ERR(msg_ptr)) {
 999                ret = PTR_ERR(msg_ptr);
1000                goto out_fput;
1001        }
1002        msg_ptr->m_ts = msg_len;
1003        msg_ptr->m_type = msg_prio;
1004
1005        /*
1006         * msg_insert really wants us to have a valid, spare node struct so
1007         * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1008         * fall back to that if necessary.
1009         */
1010        if (!info->node_cache)
1011                new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1012
1013        spin_lock(&info->lock);
1014
1015        if (!info->node_cache && new_leaf) {
1016                /* Save our speculative allocation into the cache */
1017                INIT_LIST_HEAD(&new_leaf->msg_list);
1018                info->node_cache = new_leaf;
1019                info->qsize += sizeof(*new_leaf);
1020                new_leaf = NULL;
1021        } else {
1022                kfree(new_leaf);
1023        }
1024
1025        if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1026                if (f.file->f_flags & O_NONBLOCK) {
1027                        ret = -EAGAIN;
1028                } else {
1029                        wait.task = current;
1030                        wait.msg = (void *) msg_ptr;
1031                        wait.state = STATE_NONE;
1032                        ret = wq_sleep(info, SEND, timeout, &wait);
1033                        /*
1034                         * wq_sleep must be called with info->lock held, and
1035                         * returns with the lock released
1036                         */
1037                        goto out_free;
1038                }
1039        } else {
1040                receiver = wq_get_first_waiter(info, RECV);
1041                if (receiver) {
1042                        pipelined_send(info, msg_ptr, receiver);
1043                } else {
1044                        /* adds message to the queue */
1045                        ret = msg_insert(msg_ptr, info);
1046                        if (ret)
1047                                goto out_unlock;
1048                        __do_notify(info);
1049                }
1050                inode->i_atime = inode->i_mtime = inode->i_ctime =
1051                                CURRENT_TIME;
1052        }
1053out_unlock:
1054        spin_unlock(&info->lock);
1055out_free:
1056        if (ret)
1057                free_msg(msg_ptr);
1058out_fput:
1059        fdput(f);
1060out:
1061        return ret;
1062}
1063
1064SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1065                size_t, msg_len, unsigned int __user *, u_msg_prio,
1066                const struct timespec __user *, u_abs_timeout)
1067{
1068        ssize_t ret;
1069        struct msg_msg *msg_ptr;
1070        struct fd f;
1071        struct inode *inode;
1072        struct mqueue_inode_info *info;
1073        struct ext_wait_queue wait;
1074        ktime_t expires, *timeout = NULL;
1075        struct timespec ts;
1076        struct posix_msg_tree_node *new_leaf = NULL;
1077
1078        if (u_abs_timeout) {
1079                int res = prepare_timeout(u_abs_timeout, &expires, &ts);
1080                if (res)
1081                        return res;
1082                timeout = &expires;
1083        }
1084
1085        audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL);
1086
1087        f = fdget(mqdes);
1088        if (unlikely(!f.file)) {
1089                ret = -EBADF;
1090                goto out;
1091        }
1092
1093        inode = f.file->f_path.dentry->d_inode;
1094        if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1095                ret = -EBADF;
1096                goto out_fput;
1097        }
1098        info = MQUEUE_I(inode);
1099        audit_inode(NULL, f.file->f_path.dentry, 0);
1100
1101        if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1102                ret = -EBADF;
1103                goto out_fput;
1104        }
1105
1106        /* checks if buffer is big enough */
1107        if (unlikely(msg_len < info->attr.mq_msgsize)) {
1108                ret = -EMSGSIZE;
1109                goto out_fput;
1110        }
1111
1112        /*
1113         * msg_insert really wants us to have a valid, spare node struct so
1114         * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1115         * fall back to that if necessary.
1116         */
1117        if (!info->node_cache)
1118                new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1119
1120        spin_lock(&info->lock);
1121
1122        if (!info->node_cache && new_leaf) {
1123                /* Save our speculative allocation into the cache */
1124                INIT_LIST_HEAD(&new_leaf->msg_list);
1125                info->node_cache = new_leaf;
1126                info->qsize += sizeof(*new_leaf);
1127        } else {
1128                kfree(new_leaf);
1129        }
1130
1131        if (info->attr.mq_curmsgs == 0) {
1132                if (f.file->f_flags & O_NONBLOCK) {
1133                        spin_unlock(&info->lock);
1134                        ret = -EAGAIN;
1135                } else {
1136                        wait.task = current;
1137                        wait.state = STATE_NONE;
1138                        ret = wq_sleep(info, RECV, timeout, &wait);
1139                        msg_ptr = wait.msg;
1140                }
1141        } else {
1142                msg_ptr = msg_get(info);
1143
1144                inode->i_atime = inode->i_mtime = inode->i_ctime =
1145                                CURRENT_TIME;
1146
1147                /* There is now free space in queue. */
1148                pipelined_receive(info);
1149                spin_unlock(&info->lock);
1150                ret = 0;
1151        }
1152        if (ret == 0) {
1153                ret = msg_ptr->m_ts;
1154
1155                if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1156                        store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1157                        ret = -EFAULT;
1158                }
1159                free_msg(msg_ptr);
1160        }
1161out_fput:
1162        fdput(f);
1163out:
1164        return ret;
1165}
1166
1167/*
1168 * Notes: the case when user wants us to deregister (with NULL as pointer)
1169 * and he isn't currently owner of notification, will be silently discarded.
1170 * It isn't explicitly defined in the POSIX.
1171 */
1172SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1173                const struct sigevent __user *, u_notification)
1174{
1175        int ret;
1176        struct fd f;
1177        struct sock *sock;
1178        struct inode *inode;
1179        struct sigevent notification;
1180        struct mqueue_inode_info *info;
1181        struct sk_buff *nc;
1182
1183        if (u_notification) {
1184                if (copy_from_user(&notification, u_notification,
1185                                        sizeof(struct sigevent)))
1186                        return -EFAULT;
1187        }
1188
1189        audit_mq_notify(mqdes, u_notification ? &notification : NULL);
1190
1191        nc = NULL;
1192        sock = NULL;
1193        if (u_notification != NULL) {
1194                if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1195                             notification.sigev_notify != SIGEV_SIGNAL &&
1196                             notification.sigev_notify != SIGEV_THREAD))
1197                        return -EINVAL;
1198                if (notification.sigev_notify == SIGEV_SIGNAL &&
1199                        !valid_signal(notification.sigev_signo)) {
1200                        return -EINVAL;
1201                }
1202                if (notification.sigev_notify == SIGEV_THREAD) {
1203                        long timeo;
1204
1205                        /* create the notify skb */
1206                        nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1207                        if (!nc) {
1208                                ret = -ENOMEM;
1209                                goto out;
1210                        }
1211                        if (copy_from_user(nc->data,
1212                                        notification.sigev_value.sival_ptr,
1213                                        NOTIFY_COOKIE_LEN)) {
1214                                ret = -EFAULT;
1215                                goto out;
1216                        }
1217
1218                        /* TODO: add a header? */
1219                        skb_put(nc, NOTIFY_COOKIE_LEN);
1220                        /* and attach it to the socket */
1221retry:
1222                        f = fdget(notification.sigev_signo);
1223                        if (!f.file) {
1224                                ret = -EBADF;
1225                                goto out;
1226                        }
1227                        sock = netlink_getsockbyfilp(f.file);
1228                        fdput(f);
1229                        if (IS_ERR(sock)) {
1230                                ret = PTR_ERR(sock);
1231                                sock = NULL;
1232                                goto out;
1233                        }
1234
1235                        timeo = MAX_SCHEDULE_TIMEOUT;
1236                        ret = netlink_attachskb(sock, nc, &timeo, NULL);
1237                        if (ret == 1)
1238                                goto retry;
1239                        if (ret) {
1240                                sock = NULL;
1241                                nc = NULL;
1242                                goto out;
1243                        }
1244                }
1245        }
1246
1247        f = fdget(mqdes);
1248        if (!f.file) {
1249                ret = -EBADF;
1250                goto out;
1251        }
1252
1253        inode = f.file->f_path.dentry->d_inode;
1254        if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1255                ret = -EBADF;
1256                goto out_fput;
1257        }
1258        info = MQUEUE_I(inode);
1259
1260        ret = 0;
1261        spin_lock(&info->lock);
1262        if (u_notification == NULL) {
1263                if (info->notify_owner == task_tgid(current)) {
1264                        remove_notification(info);
1265                        inode->i_atime = inode->i_ctime = CURRENT_TIME;
1266                }
1267        } else if (info->notify_owner != NULL) {
1268                ret = -EBUSY;
1269        } else {
1270                switch (notification.sigev_notify) {
1271                case SIGEV_NONE:
1272                        info->notify.sigev_notify = SIGEV_NONE;
1273                        break;
1274                case SIGEV_THREAD:
1275                        info->notify_sock = sock;
1276                        info->notify_cookie = nc;
1277                        sock = NULL;
1278                        nc = NULL;
1279                        info->notify.sigev_notify = SIGEV_THREAD;
1280                        break;
1281                case SIGEV_SIGNAL:
1282                        info->notify.sigev_signo = notification.sigev_signo;
1283                        info->notify.sigev_value = notification.sigev_value;
1284                        info->notify.sigev_notify = SIGEV_SIGNAL;
1285                        break;
1286                }
1287
1288                info->notify_owner = get_pid(task_tgid(current));
1289                info->notify_user_ns = get_user_ns(current_user_ns());
1290                inode->i_atime = inode->i_ctime = CURRENT_TIME;
1291        }
1292        spin_unlock(&info->lock);
1293out_fput:
1294        fdput(f);
1295out:
1296        if (sock) {
1297                netlink_detachskb(sock, nc);
1298        } else if (nc) {
1299                dev_kfree_skb(nc);
1300        }
1301        return ret;
1302}
1303
1304SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1305                const struct mq_attr __user *, u_mqstat,
1306                struct mq_attr __user *, u_omqstat)
1307{
1308        int ret;
1309        struct mq_attr mqstat, omqstat;
1310        struct fd f;
1311        struct inode *inode;
1312        struct mqueue_inode_info *info;
1313
1314        if (u_mqstat != NULL) {
1315                if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1316                        return -EFAULT;
1317                if (mqstat.mq_flags & (~O_NONBLOCK))
1318                        return -EINVAL;
1319        }
1320
1321        f = fdget(mqdes);
1322        if (!f.file) {
1323                ret = -EBADF;
1324                goto out;
1325        }
1326
1327        inode = f.file->f_path.dentry->d_inode;
1328        if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1329                ret = -EBADF;
1330                goto out_fput;
1331        }
1332        info = MQUEUE_I(inode);
1333
1334        spin_lock(&info->lock);
1335
1336        omqstat = info->attr;
1337        omqstat.mq_flags = f.file->f_flags & O_NONBLOCK;
1338        if (u_mqstat) {
1339                audit_mq_getsetattr(mqdes, &mqstat);
1340                spin_lock(&f.file->f_lock);
1341                if (mqstat.mq_flags & O_NONBLOCK)
1342                        f.file->f_flags |= O_NONBLOCK;
1343                else
1344                        f.file->f_flags &= ~O_NONBLOCK;
1345                spin_unlock(&f.file->f_lock);
1346
1347                inode->i_atime = inode->i_ctime = CURRENT_TIME;
1348        }
1349
1350        spin_unlock(&info->lock);
1351
1352        ret = 0;
1353        if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1354                                                sizeof(struct mq_attr)))
1355                ret = -EFAULT;
1356
1357out_fput:
1358        fdput(f);
1359out:
1360        return ret;
1361}
1362
1363static const struct inode_operations mqueue_dir_inode_operations = {
1364        .lookup = simple_lookup,
1365        .create = mqueue_create,
1366        .unlink = mqueue_unlink,
1367};
1368
1369static const struct file_operations mqueue_file_operations = {
1370        .flush = mqueue_flush_file,
1371        .poll = mqueue_poll_file,
1372        .read = mqueue_read_file,
1373        .llseek = default_llseek,
1374};
1375
1376static const struct super_operations mqueue_super_ops = {
1377        .alloc_inode = mqueue_alloc_inode,
1378        .destroy_inode = mqueue_destroy_inode,
1379        .evict_inode = mqueue_evict_inode,
1380        .statfs = simple_statfs,
1381};
1382
1383static struct file_system_type mqueue_fs_type = {
1384        .name = "mqueue",
1385        .mount = mqueue_mount,
1386        .kill_sb = kill_litter_super,
1387};
1388
1389int mq_init_ns(struct ipc_namespace *ns)
1390{
1391        ns->mq_queues_count  = 0;
1392        ns->mq_queues_max    = DFLT_QUEUESMAX;
1393        ns->mq_msg_max       = DFLT_MSGMAX;
1394        ns->mq_msgsize_max   = DFLT_MSGSIZEMAX;
1395        ns->mq_msg_default   = DFLT_MSG;
1396        ns->mq_msgsize_default  = DFLT_MSGSIZE;
1397
1398        ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1399        if (IS_ERR(ns->mq_mnt)) {
1400                int err = PTR_ERR(ns->mq_mnt);
1401                ns->mq_mnt = NULL;
1402                return err;
1403        }
1404        return 0;
1405}
1406
1407void mq_clear_sbinfo(struct ipc_namespace *ns)
1408{
1409        ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1410}
1411
1412void mq_put_mnt(struct ipc_namespace *ns)
1413{
1414        kern_unmount(ns->mq_mnt);
1415}
1416
1417static int __init init_mqueue_fs(void)
1418{
1419        int error;
1420
1421        mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1422                                sizeof(struct mqueue_inode_info), 0,
1423                                SLAB_HWCACHE_ALIGN, init_once);
1424        if (mqueue_inode_cachep == NULL)
1425                return -ENOMEM;
1426
1427        /* ignore failures - they are not fatal */
1428        mq_sysctl_table = mq_register_sysctl_table();
1429
1430        error = register_filesystem(&mqueue_fs_type);
1431        if (error)
1432                goto out_sysctl;
1433
1434        spin_lock_init(&mq_lock);
1435
1436        error = mq_init_ns(&init_ipc_ns);
1437        if (error)
1438                goto out_filesystem;
1439
1440        return 0;
1441
1442out_filesystem:
1443        unregister_filesystem(&mqueue_fs_type);
1444out_sysctl:
1445        if (mq_sysctl_table)
1446                unregister_sysctl_table(mq_sysctl_table);
1447        kmem_cache_destroy(mqueue_inode_cachep);
1448        return error;
1449}
1450
1451__initcall(init_mqueue_fs);
1452
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