linux/ipc/mqueue.c
<<
>>
Prefs
   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                rb_init_node(&leaf->rb_node);
 146                INIT_LIST_HEAD(&leaf->msg_list);
 147                info->qsize += sizeof(*leaf);
 148        }
 149        leaf->priority = msg->m_type;
 150        rb_link_node(&leaf->rb_node, parent, p);
 151        rb_insert_color(&leaf->rb_node, &info->msg_tree);
 152insert_msg:
 153        info->attr.mq_curmsgs++;
 154        info->qsize += msg->m_ts;
 155        list_add_tail(&msg->m_list, &leaf->msg_list);
 156        return 0;
 157}
 158
 159static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
 160{
 161        struct rb_node **p, *parent = NULL;
 162        struct posix_msg_tree_node *leaf;
 163        struct msg_msg *msg;
 164
 165try_again:
 166        p = &info->msg_tree.rb_node;
 167        while (*p) {
 168                parent = *p;
 169                /*
 170                 * During insert, low priorities go to the left and high to the
 171                 * right.  On receive, we want the highest priorities first, so
 172                 * walk all the way to the right.
 173                 */
 174                p = &(*p)->rb_right;
 175        }
 176        if (!parent) {
 177                if (info->attr.mq_curmsgs) {
 178                        pr_warn_once("Inconsistency in POSIX message queue, "
 179                                     "no tree element, but supposedly messages "
 180                                     "should exist!\n");
 181                        info->attr.mq_curmsgs = 0;
 182                }
 183                return NULL;
 184        }
 185        leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
 186        if (unlikely(list_empty(&leaf->msg_list))) {
 187                pr_warn_once("Inconsistency in POSIX message queue, "
 188                             "empty leaf node but we haven't implemented "
 189                             "lazy leaf delete!\n");
 190                rb_erase(&leaf->rb_node, &info->msg_tree);
 191                if (info->node_cache) {
 192                        info->qsize -= sizeof(*leaf);
 193                        kfree(leaf);
 194                } else {
 195                        info->node_cache = leaf;
 196                }
 197                goto try_again;
 198        } else {
 199                msg = list_first_entry(&leaf->msg_list,
 200                                       struct msg_msg, m_list);
 201                list_del(&msg->m_list);
 202                if (list_empty(&leaf->msg_list)) {
 203                        rb_erase(&leaf->rb_node, &info->msg_tree);
 204                        if (info->node_cache) {
 205                                info->qsize -= sizeof(*leaf);
 206                                kfree(leaf);
 207                        } else {
 208                                info->node_cache = leaf;
 209                        }
 210                }
 211        }
 212        info->attr.mq_curmsgs--;
 213        info->qsize -= msg->m_ts;
 214        return msg;
 215}
 216
 217static struct inode *mqueue_get_inode(struct super_block *sb,
 218                struct ipc_namespace *ipc_ns, umode_t mode,
 219                struct mq_attr *attr)
 220{
 221        struct user_struct *u = current_user();
 222        struct inode *inode;
 223        int ret = -ENOMEM;
 224
 225        inode = new_inode(sb);
 226        if (!inode)
 227                goto err;
 228
 229        inode->i_ino = get_next_ino();
 230        inode->i_mode = mode;
 231        inode->i_uid = current_fsuid();
 232        inode->i_gid = current_fsgid();
 233        inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME;
 234
 235        if (S_ISREG(mode)) {
 236                struct mqueue_inode_info *info;
 237                unsigned long mq_bytes, mq_treesize;
 238
 239                inode->i_fop = &mqueue_file_operations;
 240                inode->i_size = FILENT_SIZE;
 241                /* mqueue specific info */
 242                info = MQUEUE_I(inode);
 243                spin_lock_init(&info->lock);
 244                init_waitqueue_head(&info->wait_q);
 245                INIT_LIST_HEAD(&info->e_wait_q[0].list);
 246                INIT_LIST_HEAD(&info->e_wait_q[1].list);
 247                info->notify_owner = NULL;
 248                info->notify_user_ns = NULL;
 249                info->qsize = 0;
 250                info->user = NULL;      /* set when all is ok */
 251                info->msg_tree = RB_ROOT;
 252                info->node_cache = NULL;
 253                memset(&info->attr, 0, sizeof(info->attr));
 254                info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
 255                                           ipc_ns->mq_msg_default);
 256                info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
 257                                            ipc_ns->mq_msgsize_default);
 258                if (attr) {
 259                        info->attr.mq_maxmsg = attr->mq_maxmsg;
 260                        info->attr.mq_msgsize = attr->mq_msgsize;
 261                }
 262                /*
 263                 * We used to allocate a static array of pointers and account
 264                 * the size of that array as well as one msg_msg struct per
 265                 * possible message into the queue size. That's no longer
 266                 * accurate as the queue is now an rbtree and will grow and
 267                 * shrink depending on usage patterns.  We can, however, still
 268                 * account one msg_msg struct per message, but the nodes are
 269                 * allocated depending on priority usage, and most programs
 270                 * only use one, or a handful, of priorities.  However, since
 271                 * this is pinned memory, we need to assume worst case, so
 272                 * that means the min(mq_maxmsg, max_priorities) * struct
 273                 * posix_msg_tree_node.
 274                 */
 275                mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
 276                        min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
 277                        sizeof(struct posix_msg_tree_node);
 278
 279                mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
 280                                          info->attr.mq_msgsize);
 281
 282                spin_lock(&mq_lock);
 283                if (u->mq_bytes + mq_bytes < u->mq_bytes ||
 284                    u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
 285                        spin_unlock(&mq_lock);
 286                        /* mqueue_evict_inode() releases info->messages */
 287                        ret = -EMFILE;
 288                        goto out_inode;
 289                }
 290                u->mq_bytes += mq_bytes;
 291                spin_unlock(&mq_lock);
 292
 293                /* all is ok */
 294                info->user = get_uid(u);
 295        } else if (S_ISDIR(mode)) {
 296                inc_nlink(inode);
 297                /* Some things misbehave if size == 0 on a directory */
 298                inode->i_size = 2 * DIRENT_SIZE;
 299                inode->i_op = &mqueue_dir_inode_operations;
 300                inode->i_fop = &simple_dir_operations;
 301        }
 302
 303        return inode;
 304out_inode:
 305        iput(inode);
 306err:
 307        return ERR_PTR(ret);
 308}
 309
 310static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
 311{
 312        struct inode *inode;
 313        struct ipc_namespace *ns = data;
 314
 315        sb->s_blocksize = PAGE_CACHE_SIZE;
 316        sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 317        sb->s_magic = MQUEUE_MAGIC;
 318        sb->s_op = &mqueue_super_ops;
 319
 320        inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
 321        if (IS_ERR(inode))
 322                return PTR_ERR(inode);
 323
 324        sb->s_root = d_make_root(inode);
 325        if (!sb->s_root)
 326                return -ENOMEM;
 327        return 0;
 328}
 329
 330static struct dentry *mqueue_mount(struct file_system_type *fs_type,
 331                         int flags, const char *dev_name,
 332                         void *data)
 333{
 334        if (!(flags & MS_KERNMOUNT))
 335                data = current->nsproxy->ipc_ns;
 336        return mount_ns(fs_type, flags, data, mqueue_fill_super);
 337}
 338
 339static void init_once(void *foo)
 340{
 341        struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
 342
 343        inode_init_once(&p->vfs_inode);
 344}
 345
 346static struct inode *mqueue_alloc_inode(struct super_block *sb)
 347{
 348        struct mqueue_inode_info *ei;
 349
 350        ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
 351        if (!ei)
 352                return NULL;
 353        return &ei->vfs_inode;
 354}
 355
 356static void mqueue_i_callback(struct rcu_head *head)
 357{
 358        struct inode *inode = container_of(head, struct inode, i_rcu);
 359        kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
 360}
 361
 362static void mqueue_destroy_inode(struct inode *inode)
 363{
 364        call_rcu(&inode->i_rcu, mqueue_i_callback);
 365}
 366
 367static void mqueue_evict_inode(struct inode *inode)
 368{
 369        struct mqueue_inode_info *info;
 370        struct user_struct *user;
 371        unsigned long mq_bytes, mq_treesize;
 372        struct ipc_namespace *ipc_ns;
 373        struct msg_msg *msg;
 374
 375        clear_inode(inode);
 376
 377        if (S_ISDIR(inode->i_mode))
 378                return;
 379
 380        ipc_ns = get_ns_from_inode(inode);
 381        info = MQUEUE_I(inode);
 382        spin_lock(&info->lock);
 383        while ((msg = msg_get(info)) != NULL)
 384                free_msg(msg);
 385        kfree(info->node_cache);
 386        spin_unlock(&info->lock);
 387
 388        /* Total amount of bytes accounted for the mqueue */
 389        mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
 390                min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
 391                sizeof(struct posix_msg_tree_node);
 392
 393        mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
 394                                  info->attr.mq_msgsize);
 395
 396        user = info->user;
 397        if (user) {
 398                spin_lock(&mq_lock);
 399                user->mq_bytes -= mq_bytes;
 400                /*
 401                 * get_ns_from_inode() ensures that the
 402                 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
 403                 * to which we now hold a reference, or it is NULL.
 404                 * We can't put it here under mq_lock, though.
 405                 */
 406                if (ipc_ns)
 407                        ipc_ns->mq_queues_count--;
 408                spin_unlock(&mq_lock);
 409                free_uid(user);
 410        }
 411        if (ipc_ns)
 412                put_ipc_ns(ipc_ns);
 413}
 414
 415static int mqueue_create(struct inode *dir, struct dentry *dentry,
 416                                umode_t mode, bool excl)
 417{
 418        struct inode *inode;
 419        struct mq_attr *attr = dentry->d_fsdata;
 420        int error;
 421        struct ipc_namespace *ipc_ns;
 422
 423        spin_lock(&mq_lock);
 424        ipc_ns = __get_ns_from_inode(dir);
 425        if (!ipc_ns) {
 426                error = -EACCES;
 427                goto out_unlock;
 428        }
 429        if (ipc_ns->mq_queues_count >= HARD_QUEUESMAX ||
 430            (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
 431             !capable(CAP_SYS_RESOURCE))) {
 432                error = -ENOSPC;
 433                goto out_unlock;
 434        }
 435        ipc_ns->mq_queues_count++;
 436        spin_unlock(&mq_lock);
 437
 438        inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
 439        if (IS_ERR(inode)) {
 440                error = PTR_ERR(inode);
 441                spin_lock(&mq_lock);
 442                ipc_ns->mq_queues_count--;
 443                goto out_unlock;
 444        }
 445
 446        put_ipc_ns(ipc_ns);
 447        dir->i_size += DIRENT_SIZE;
 448        dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
 449
 450        d_instantiate(dentry, inode);
 451        dget(dentry);
 452        return 0;
 453out_unlock:
 454        spin_unlock(&mq_lock);
 455        if (ipc_ns)
 456                put_ipc_ns(ipc_ns);
 457        return error;
 458}
 459
 460static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
 461{
 462        struct inode *inode = dentry->d_inode;
 463
 464        dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
 465        dir->i_size -= DIRENT_SIZE;
 466        drop_nlink(inode);
 467        dput(dentry);
 468        return 0;
 469}
 470
 471/*
 472*       This is routine for system read from queue file.
 473*       To avoid mess with doing here some sort of mq_receive we allow
 474*       to read only queue size & notification info (the only values
 475*       that are interesting from user point of view and aren't accessible
 476*       through std routines)
 477*/
 478static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
 479                                size_t count, loff_t *off)
 480{
 481        struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
 482        char buffer[FILENT_SIZE];
 483        ssize_t ret;
 484
 485        spin_lock(&info->lock);
 486        snprintf(buffer, sizeof(buffer),
 487                        "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
 488                        info->qsize,
 489                        info->notify_owner ? info->notify.sigev_notify : 0,
 490                        (info->notify_owner &&
 491                         info->notify.sigev_notify == SIGEV_SIGNAL) ?
 492                                info->notify.sigev_signo : 0,
 493                        pid_vnr(info->notify_owner));
 494        spin_unlock(&info->lock);
 495        buffer[sizeof(buffer)-1] = '\0';
 496
 497        ret = simple_read_from_buffer(u_data, count, off, buffer,
 498                                strlen(buffer));
 499        if (ret <= 0)
 500                return ret;
 501
 502        filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME;
 503        return ret;
 504}
 505
 506static int mqueue_flush_file(struct file *filp, fl_owner_t id)
 507{
 508        struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
 509
 510        spin_lock(&info->lock);
 511        if (task_tgid(current) == info->notify_owner)
 512                remove_notification(info);
 513
 514        spin_unlock(&info->lock);
 515        return 0;
 516}
 517
 518static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
 519{
 520        struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
 521        int retval = 0;
 522
 523        poll_wait(filp, &info->wait_q, poll_tab);
 524
 525        spin_lock(&info->lock);
 526        if (info->attr.mq_curmsgs)
 527                retval = POLLIN | POLLRDNORM;
 528
 529        if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
 530                retval |= POLLOUT | POLLWRNORM;
 531        spin_unlock(&info->lock);
 532
 533        return retval;
 534}
 535
 536/* Adds current to info->e_wait_q[sr] before element with smaller prio */
 537static void wq_add(struct mqueue_inode_info *info, int sr,
 538                        struct ext_wait_queue *ewp)
 539{
 540        struct ext_wait_queue *walk;
 541
 542        ewp->task = current;
 543
 544        list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
 545                if (walk->task->static_prio <= current->static_prio) {
 546                        list_add_tail(&ewp->list, &walk->list);
 547                        return;
 548                }
 549        }
 550        list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
 551}
 552
 553/*
 554 * Puts current task to sleep. Caller must hold queue lock. After return
 555 * lock isn't held.
 556 * sr: SEND or RECV
 557 */
 558static int wq_sleep(struct mqueue_inode_info *info, int sr,
 559                    ktime_t *timeout, struct ext_wait_queue *ewp)
 560{
 561        int retval;
 562        signed long time;
 563
 564        wq_add(info, sr, ewp);
 565
 566        for (;;) {
 567                set_current_state(TASK_INTERRUPTIBLE);
 568
 569                spin_unlock(&info->lock);
 570                time = schedule_hrtimeout_range_clock(timeout, 0,
 571                        HRTIMER_MODE_ABS, CLOCK_REALTIME);
 572
 573                while (ewp->state == STATE_PENDING)
 574                        cpu_relax();
 575
 576                if (ewp->state == STATE_READY) {
 577                        retval = 0;
 578                        goto out;
 579                }
 580                spin_lock(&info->lock);
 581                if (ewp->state == STATE_READY) {
 582                        retval = 0;
 583                        goto out_unlock;
 584                }
 585                if (signal_pending(current)) {
 586                        retval = -ERESTARTSYS;
 587                        break;
 588                }
 589                if (time == 0) {
 590                        retval = -ETIMEDOUT;
 591                        break;
 592                }
 593        }
 594        list_del(&ewp->list);
 595out_unlock:
 596        spin_unlock(&info->lock);
 597out:
 598        return retval;
 599}
 600
 601/*
 602 * Returns waiting task that should be serviced first or NULL if none exists
 603 */
 604static struct ext_wait_queue *wq_get_first_waiter(
 605                struct mqueue_inode_info *info, int sr)
 606{
 607        struct list_head *ptr;
 608
 609        ptr = info->e_wait_q[sr].list.prev;
 610        if (ptr == &info->e_wait_q[sr].list)
 611                return NULL;
 612        return list_entry(ptr, struct ext_wait_queue, list);
 613}
 614
 615
 616static inline void set_cookie(struct sk_buff *skb, char code)
 617{
 618        ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
 619}
 620
 621/*
 622 * The next function is only to split too long sys_mq_timedsend
 623 */
 624static void __do_notify(struct mqueue_inode_info *info)
 625{
 626        /* notification
 627         * invoked when there is registered process and there isn't process
 628         * waiting synchronously for message AND state of queue changed from
 629         * empty to not empty. Here we are sure that no one is waiting
 630         * synchronously. */
 631        if (info->notify_owner &&
 632            info->attr.mq_curmsgs == 1) {
 633                struct siginfo sig_i;
 634                switch (info->notify.sigev_notify) {
 635                case SIGEV_NONE:
 636                        break;
 637                case SIGEV_SIGNAL:
 638                        /* sends signal */
 639
 640                        sig_i.si_signo = info->notify.sigev_signo;
 641                        sig_i.si_errno = 0;
 642                        sig_i.si_code = SI_MESGQ;
 643                        sig_i.si_value = info->notify.sigev_value;
 644                        /* map current pid/uid into info->owner's namespaces */
 645                        rcu_read_lock();
 646                        sig_i.si_pid = task_tgid_nr_ns(current,
 647                                                ns_of_pid(info->notify_owner));
 648                        sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
 649                        rcu_read_unlock();
 650
 651                        kill_pid_info(info->notify.sigev_signo,
 652                                      &sig_i, info->notify_owner);
 653                        break;
 654                case SIGEV_THREAD:
 655                        set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
 656                        netlink_sendskb(info->notify_sock, info->notify_cookie);
 657                        break;
 658                }
 659                /* after notification unregisters process */
 660                put_pid(info->notify_owner);
 661                put_user_ns(info->notify_user_ns);
 662                info->notify_owner = NULL;
 663                info->notify_user_ns = NULL;
 664        }
 665        wake_up(&info->wait_q);
 666}
 667
 668static int prepare_timeout(const struct timespec __user *u_abs_timeout,
 669                           ktime_t *expires, struct timespec *ts)
 670{
 671        if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec)))
 672                return -EFAULT;
 673        if (!timespec_valid(ts))
 674                return -EINVAL;
 675
 676        *expires = timespec_to_ktime(*ts);
 677        return 0;
 678}
 679
 680static void remove_notification(struct mqueue_inode_info *info)
 681{
 682        if (info->notify_owner != NULL &&
 683            info->notify.sigev_notify == SIGEV_THREAD) {
 684                set_cookie(info->notify_cookie, NOTIFY_REMOVED);
 685                netlink_sendskb(info->notify_sock, info->notify_cookie);
 686        }
 687        put_pid(info->notify_owner);
 688        put_user_ns(info->notify_user_ns);
 689        info->notify_owner = NULL;
 690        info->notify_user_ns = NULL;
 691}
 692
 693static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
 694{
 695        int mq_treesize;
 696        unsigned long total_size;
 697
 698        if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
 699                return -EINVAL;
 700        if (capable(CAP_SYS_RESOURCE)) {
 701                if (attr->mq_maxmsg > HARD_MSGMAX ||
 702                    attr->mq_msgsize > HARD_MSGSIZEMAX)
 703                        return -EINVAL;
 704        } else {
 705                if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
 706                                attr->mq_msgsize > ipc_ns->mq_msgsize_max)
 707                        return -EINVAL;
 708        }
 709        /* check for overflow */
 710        if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
 711                return -EOVERFLOW;
 712        mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) +
 713                min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) *
 714                sizeof(struct posix_msg_tree_node);
 715        total_size = attr->mq_maxmsg * attr->mq_msgsize;
 716        if (total_size + mq_treesize < total_size)
 717                return -EOVERFLOW;
 718        return 0;
 719}
 720
 721/*
 722 * Invoked when creating a new queue via sys_mq_open
 723 */
 724static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir,
 725                        struct path *path, int oflag, umode_t mode,
 726                        struct mq_attr *attr)
 727{
 728        const struct cred *cred = current_cred();
 729        int ret;
 730
 731        if (attr) {
 732                ret = mq_attr_ok(ipc_ns, attr);
 733                if (ret)
 734                        return ERR_PTR(ret);
 735                /* store for use during create */
 736                path->dentry->d_fsdata = attr;
 737        } else {
 738                struct mq_attr def_attr;
 739
 740                def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
 741                                         ipc_ns->mq_msg_default);
 742                def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
 743                                          ipc_ns->mq_msgsize_default);
 744                ret = mq_attr_ok(ipc_ns, &def_attr);
 745                if (ret)
 746                        return ERR_PTR(ret);
 747        }
 748
 749        mode &= ~current_umask();
 750        ret = vfs_create(dir, path->dentry, mode, true);
 751        path->dentry->d_fsdata = NULL;
 752        if (ret)
 753                return ERR_PTR(ret);
 754        return dentry_open(path, oflag, cred);
 755}
 756
 757/* Opens existing queue */
 758static struct file *do_open(struct path *path, int oflag)
 759{
 760        static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
 761                                                  MAY_READ | MAY_WRITE };
 762        int acc;
 763        if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
 764                return ERR_PTR(-EINVAL);
 765        acc = oflag2acc[oflag & O_ACCMODE];
 766        if (inode_permission(path->dentry->d_inode, acc))
 767                return ERR_PTR(-EACCES);
 768        return dentry_open(path, oflag, current_cred());
 769}
 770
 771SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
 772                struct mq_attr __user *, u_attr)
 773{
 774        struct path path;
 775        struct file *filp;
 776        char *name;
 777        struct mq_attr attr;
 778        int fd, error;
 779        struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
 780        struct vfsmount *mnt = ipc_ns->mq_mnt;
 781        struct dentry *root = mnt->mnt_root;
 782        int ro;
 783
 784        if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
 785                return -EFAULT;
 786
 787        audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
 788
 789        if (IS_ERR(name = getname(u_name)))
 790                return PTR_ERR(name);
 791
 792        fd = get_unused_fd_flags(O_CLOEXEC);
 793        if (fd < 0)
 794                goto out_putname;
 795
 796        ro = mnt_want_write(mnt);       /* we'll drop it in any case */
 797        error = 0;
 798        mutex_lock(&root->d_inode->i_mutex);
 799        path.dentry = lookup_one_len(name, root, strlen(name));
 800        if (IS_ERR(path.dentry)) {
 801                error = PTR_ERR(path.dentry);
 802                goto out_putfd;
 803        }
 804        path.mnt = mntget(mnt);
 805
 806        if (oflag & O_CREAT) {
 807                if (path.dentry->d_inode) {     /* entry already exists */
 808                        audit_inode(name, path.dentry);
 809                        if (oflag & O_EXCL) {
 810                                error = -EEXIST;
 811                                goto out;
 812                        }
 813                        filp = do_open(&path, oflag);
 814                } else {
 815                        if (ro) {
 816                                error = ro;
 817                                goto out;
 818                        }
 819                        filp = do_create(ipc_ns, root->d_inode,
 820                                                &path, oflag, mode,
 821                                                u_attr ? &attr : NULL);
 822                }
 823        } else {
 824                if (!path.dentry->d_inode) {
 825                        error = -ENOENT;
 826                        goto out;
 827                }
 828                audit_inode(name, path.dentry);
 829                filp = do_open(&path, oflag);
 830        }
 831
 832        if (!IS_ERR(filp))
 833                fd_install(fd, filp);
 834        else
 835                error = PTR_ERR(filp);
 836out:
 837        path_put(&path);
 838out_putfd:
 839        if (error) {
 840                put_unused_fd(fd);
 841                fd = error;
 842        }
 843        mutex_unlock(&root->d_inode->i_mutex);
 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        char *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, mnt->mnt_root, strlen(name));
 868        if (IS_ERR(dentry)) {
 869                err = PTR_ERR(dentry);
 870                goto out_unlock;
 871        }
 872
 873        inode = dentry->d_inode;
 874        if (!inode) {
 875                err = -ENOENT;
 876        } else {
 877                ihold(inode);
 878                err = vfs_unlink(dentry->d_parent->d_inode, dentry);
 879        }
 880        dput(dentry);
 881
 882out_unlock:
 883        mutex_unlock(&mnt->mnt_root->d_inode->i_mutex);
 884        if (inode)
 885                iput(inode);
 886        mnt_drop_write(mnt);
 887out_name:
 888        putname(name);
 889
 890        return err;
 891}
 892
 893/* Pipelined send and receive functions.
 894 *
 895 * If a receiver finds no waiting message, then it registers itself in the
 896 * list of waiting receivers. A sender checks that list before adding the new
 897 * message into the message array. If there is a waiting receiver, then it
 898 * bypasses the message array and directly hands the message over to the
 899 * receiver.
 900 * The receiver accepts the message and returns without grabbing the queue
 901 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
 902 * are necessary. The same algorithm is used for sysv semaphores, see
 903 * ipc/sem.c for more details.
 904 *
 905 * The same algorithm is used for senders.
 906 */
 907
 908/* pipelined_send() - send a message directly to the task waiting in
 909 * sys_mq_timedreceive() (without inserting message into a queue).
 910 */
 911static inline void pipelined_send(struct mqueue_inode_info *info,
 912                                  struct msg_msg *message,
 913                                  struct ext_wait_queue *receiver)
 914{
 915        receiver->msg = message;
 916        list_del(&receiver->list);
 917        receiver->state = STATE_PENDING;
 918        wake_up_process(receiver->task);
 919        smp_wmb();
 920        receiver->state = STATE_READY;
 921}
 922
 923/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
 924 * gets its message and put to the queue (we have one free place for sure). */
 925static inline void pipelined_receive(struct mqueue_inode_info *info)
 926{
 927        struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
 928
 929        if (!sender) {
 930                /* for poll */
 931                wake_up_interruptible(&info->wait_q);
 932                return;
 933        }
 934        if (msg_insert(sender->msg, info))
 935                return;
 936        list_del(&sender->list);
 937        sender->state = STATE_PENDING;
 938        wake_up_process(sender->task);
 939        smp_wmb();
 940        sender->state = STATE_READY;
 941}
 942
 943SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
 944                size_t, msg_len, unsigned int, msg_prio,
 945                const struct timespec __user *, u_abs_timeout)
 946{
 947        struct file *filp;
 948        struct inode *inode;
 949        struct ext_wait_queue wait;
 950        struct ext_wait_queue *receiver;
 951        struct msg_msg *msg_ptr;
 952        struct mqueue_inode_info *info;
 953        ktime_t expires, *timeout = NULL;
 954        struct timespec ts;
 955        struct posix_msg_tree_node *new_leaf = NULL;
 956        int ret = 0;
 957
 958        if (u_abs_timeout) {
 959                int res = prepare_timeout(u_abs_timeout, &expires, &ts);
 960                if (res)
 961                        return res;
 962                timeout = &expires;
 963        }
 964
 965        if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
 966                return -EINVAL;
 967
 968        audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL);
 969
 970        filp = fget(mqdes);
 971        if (unlikely(!filp)) {
 972                ret = -EBADF;
 973                goto out;
 974        }
 975
 976        inode = filp->f_path.dentry->d_inode;
 977        if (unlikely(filp->f_op != &mqueue_file_operations)) {
 978                ret = -EBADF;
 979                goto out_fput;
 980        }
 981        info = MQUEUE_I(inode);
 982        audit_inode(NULL, filp->f_path.dentry);
 983
 984        if (unlikely(!(filp->f_mode & FMODE_WRITE))) {
 985                ret = -EBADF;
 986                goto out_fput;
 987        }
 988
 989        if (unlikely(msg_len > info->attr.mq_msgsize)) {
 990                ret = -EMSGSIZE;
 991                goto out_fput;
 992        }
 993
 994        /* First try to allocate memory, before doing anything with
 995         * existing queues. */
 996        msg_ptr = load_msg(u_msg_ptr, msg_len);
 997        if (IS_ERR(msg_ptr)) {
 998                ret = PTR_ERR(msg_ptr);
 999                goto out_fput;
1000        }
1001        msg_ptr->m_ts = msg_len;
1002        msg_ptr->m_type = msg_prio;
1003
1004        /*
1005         * msg_insert really wants us to have a valid, spare node struct so
1006         * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1007         * fall back to that if necessary.
1008         */
1009        if (!info->node_cache)
1010                new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1011
1012        spin_lock(&info->lock);
1013
1014        if (!info->node_cache && new_leaf) {
1015                /* Save our speculative allocation into the cache */
1016                rb_init_node(&new_leaf->rb_node);
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 (filp->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        fput(filp);
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 file *filp;
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        filp = fget(mqdes);
1088        if (unlikely(!filp)) {
1089                ret = -EBADF;
1090                goto out;
1091        }
1092
1093        inode = filp->f_path.dentry->d_inode;
1094        if (unlikely(filp->f_op != &mqueue_file_operations)) {
1095                ret = -EBADF;
1096                goto out_fput;
1097        }
1098        info = MQUEUE_I(inode);
1099        audit_inode(NULL, filp->f_path.dentry);
1100
1101        if (unlikely(!(filp->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                rb_init_node(&new_leaf->rb_node);
1125                INIT_LIST_HEAD(&new_leaf->msg_list);
1126                info->node_cache = new_leaf;
1127                info->qsize += sizeof(*new_leaf);
1128        } else {
1129                kfree(new_leaf);
1130        }
1131
1132        if (info->attr.mq_curmsgs == 0) {
1133                if (filp->f_flags & O_NONBLOCK) {
1134                        spin_unlock(&info->lock);
1135                        ret = -EAGAIN;
1136                } else {
1137                        wait.task = current;
1138                        wait.state = STATE_NONE;
1139                        ret = wq_sleep(info, RECV, timeout, &wait);
1140                        msg_ptr = wait.msg;
1141                }
1142        } else {
1143                msg_ptr = msg_get(info);
1144
1145                inode->i_atime = inode->i_mtime = inode->i_ctime =
1146                                CURRENT_TIME;
1147
1148                /* There is now free space in queue. */
1149                pipelined_receive(info);
1150                spin_unlock(&info->lock);
1151                ret = 0;
1152        }
1153        if (ret == 0) {
1154                ret = msg_ptr->m_ts;
1155
1156                if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1157                        store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1158                        ret = -EFAULT;
1159                }
1160                free_msg(msg_ptr);
1161        }
1162out_fput:
1163        fput(filp);
1164out:
1165        return ret;
1166}
1167
1168/*
1169 * Notes: the case when user wants us to deregister (with NULL as pointer)
1170 * and he isn't currently owner of notification, will be silently discarded.
1171 * It isn't explicitly defined in the POSIX.
1172 */
1173SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1174                const struct sigevent __user *, u_notification)
1175{
1176        int ret;
1177        struct file *filp;
1178        struct sock *sock;
1179        struct inode *inode;
1180        struct sigevent notification;
1181        struct mqueue_inode_info *info;
1182        struct sk_buff *nc;
1183
1184        if (u_notification) {
1185                if (copy_from_user(&notification, u_notification,
1186                                        sizeof(struct sigevent)))
1187                        return -EFAULT;
1188        }
1189
1190        audit_mq_notify(mqdes, u_notification ? &notification : NULL);
1191
1192        nc = NULL;
1193        sock = NULL;
1194        if (u_notification != NULL) {
1195                if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1196                             notification.sigev_notify != SIGEV_SIGNAL &&
1197                             notification.sigev_notify != SIGEV_THREAD))
1198                        return -EINVAL;
1199                if (notification.sigev_notify == SIGEV_SIGNAL &&
1200                        !valid_signal(notification.sigev_signo)) {
1201                        return -EINVAL;
1202                }
1203                if (notification.sigev_notify == SIGEV_THREAD) {
1204                        long timeo;
1205
1206                        /* create the notify skb */
1207                        nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1208                        if (!nc) {
1209                                ret = -ENOMEM;
1210                                goto out;
1211                        }
1212                        if (copy_from_user(nc->data,
1213                                        notification.sigev_value.sival_ptr,
1214                                        NOTIFY_COOKIE_LEN)) {
1215                                ret = -EFAULT;
1216                                goto out;
1217                        }
1218
1219                        /* TODO: add a header? */
1220                        skb_put(nc, NOTIFY_COOKIE_LEN);
1221                        /* and attach it to the socket */
1222retry:
1223                        filp = fget(notification.sigev_signo);
1224                        if (!filp) {
1225                                ret = -EBADF;
1226                                goto out;
1227                        }
1228                        sock = netlink_getsockbyfilp(filp);
1229                        fput(filp);
1230                        if (IS_ERR(sock)) {
1231                                ret = PTR_ERR(sock);
1232                                sock = NULL;
1233                                goto out;
1234                        }
1235
1236                        timeo = MAX_SCHEDULE_TIMEOUT;
1237                        ret = netlink_attachskb(sock, nc, &timeo, NULL);
1238                        if (ret == 1)
1239                                goto retry;
1240                        if (ret) {
1241                                sock = NULL;
1242                                nc = NULL;
1243                                goto out;
1244                        }
1245                }
1246        }
1247
1248        filp = fget(mqdes);
1249        if (!filp) {
1250                ret = -EBADF;
1251                goto out;
1252        }
1253
1254        inode = filp->f_path.dentry->d_inode;
1255        if (unlikely(filp->f_op != &mqueue_file_operations)) {
1256                ret = -EBADF;
1257                goto out_fput;
1258        }
1259        info = MQUEUE_I(inode);
1260
1261        ret = 0;
1262        spin_lock(&info->lock);
1263        if (u_notification == NULL) {
1264                if (info->notify_owner == task_tgid(current)) {
1265                        remove_notification(info);
1266                        inode->i_atime = inode->i_ctime = CURRENT_TIME;
1267                }
1268        } else if (info->notify_owner != NULL) {
1269                ret = -EBUSY;
1270        } else {
1271                switch (notification.sigev_notify) {
1272                case SIGEV_NONE:
1273                        info->notify.sigev_notify = SIGEV_NONE;
1274                        break;
1275                case SIGEV_THREAD:
1276                        info->notify_sock = sock;
1277                        info->notify_cookie = nc;
1278                        sock = NULL;
1279                        nc = NULL;
1280                        info->notify.sigev_notify = SIGEV_THREAD;
1281                        break;
1282                case SIGEV_SIGNAL:
1283                        info->notify.sigev_signo = notification.sigev_signo;
1284                        info->notify.sigev_value = notification.sigev_value;
1285                        info->notify.sigev_notify = SIGEV_SIGNAL;
1286                        break;
1287                }
1288
1289                info->notify_owner = get_pid(task_tgid(current));
1290                info->notify_user_ns = get_user_ns(current_user_ns());
1291                inode->i_atime = inode->i_ctime = CURRENT_TIME;
1292        }
1293        spin_unlock(&info->lock);
1294out_fput:
1295        fput(filp);
1296out:
1297        if (sock) {
1298                netlink_detachskb(sock, nc);
1299        } else if (nc) {
1300                dev_kfree_skb(nc);
1301        }
1302        return ret;
1303}
1304
1305SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1306                const struct mq_attr __user *, u_mqstat,
1307                struct mq_attr __user *, u_omqstat)
1308{
1309        int ret;
1310        struct mq_attr mqstat, omqstat;
1311        struct file *filp;
1312        struct inode *inode;
1313        struct mqueue_inode_info *info;
1314
1315        if (u_mqstat != NULL) {
1316                if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1317                        return -EFAULT;
1318                if (mqstat.mq_flags & (~O_NONBLOCK))
1319                        return -EINVAL;
1320        }
1321
1322        filp = fget(mqdes);
1323        if (!filp) {
1324                ret = -EBADF;
1325                goto out;
1326        }
1327
1328        inode = filp->f_path.dentry->d_inode;
1329        if (unlikely(filp->f_op != &mqueue_file_operations)) {
1330                ret = -EBADF;
1331                goto out_fput;
1332        }
1333        info = MQUEUE_I(inode);
1334
1335        spin_lock(&info->lock);
1336
1337        omqstat = info->attr;
1338        omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
1339        if (u_mqstat) {
1340                audit_mq_getsetattr(mqdes, &mqstat);
1341                spin_lock(&filp->f_lock);
1342                if (mqstat.mq_flags & O_NONBLOCK)
1343                        filp->f_flags |= O_NONBLOCK;
1344                else
1345                        filp->f_flags &= ~O_NONBLOCK;
1346                spin_unlock(&filp->f_lock);
1347
1348                inode->i_atime = inode->i_ctime = CURRENT_TIME;
1349        }
1350
1351        spin_unlock(&info->lock);
1352
1353        ret = 0;
1354        if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1355                                                sizeof(struct mq_attr)))
1356                ret = -EFAULT;
1357
1358out_fput:
1359        fput(filp);
1360out:
1361        return ret;
1362}
1363
1364static const struct inode_operations mqueue_dir_inode_operations = {
1365        .lookup = simple_lookup,
1366        .create = mqueue_create,
1367        .unlink = mqueue_unlink,
1368};
1369
1370static const struct file_operations mqueue_file_operations = {
1371        .flush = mqueue_flush_file,
1372        .poll = mqueue_poll_file,
1373        .read = mqueue_read_file,
1374        .llseek = default_llseek,
1375};
1376
1377static const struct super_operations mqueue_super_ops = {
1378        .alloc_inode = mqueue_alloc_inode,
1379        .destroy_inode = mqueue_destroy_inode,
1380        .evict_inode = mqueue_evict_inode,
1381        .statfs = simple_statfs,
1382};
1383
1384static struct file_system_type mqueue_fs_type = {
1385        .name = "mqueue",
1386        .mount = mqueue_mount,
1387        .kill_sb = kill_litter_super,
1388};
1389
1390int mq_init_ns(struct ipc_namespace *ns)
1391{
1392        ns->mq_queues_count  = 0;
1393        ns->mq_queues_max    = DFLT_QUEUESMAX;
1394        ns->mq_msg_max       = DFLT_MSGMAX;
1395        ns->mq_msgsize_max   = DFLT_MSGSIZEMAX;
1396        ns->mq_msg_default   = DFLT_MSG;
1397        ns->mq_msgsize_default  = DFLT_MSGSIZE;
1398
1399        ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1400        if (IS_ERR(ns->mq_mnt)) {
1401                int err = PTR_ERR(ns->mq_mnt);
1402                ns->mq_mnt = NULL;
1403                return err;
1404        }
1405        return 0;
1406}
1407
1408void mq_clear_sbinfo(struct ipc_namespace *ns)
1409{
1410        ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1411}
1412
1413void mq_put_mnt(struct ipc_namespace *ns)
1414{
1415        kern_unmount(ns->mq_mnt);
1416}
1417
1418static int __init init_mqueue_fs(void)
1419{
1420        int error;
1421
1422        mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1423                                sizeof(struct mqueue_inode_info), 0,
1424                                SLAB_HWCACHE_ALIGN, init_once);
1425        if (mqueue_inode_cachep == NULL)
1426                return -ENOMEM;
1427
1428        /* ignore failures - they are not fatal */
1429        mq_sysctl_table = mq_register_sysctl_table();
1430
1431        error = register_filesystem(&mqueue_fs_type);
1432        if (error)
1433                goto out_sysctl;
1434
1435        spin_lock_init(&mq_lock);
1436
1437        error = mq_init_ns(&init_ipc_ns);
1438        if (error)
1439                goto out_filesystem;
1440
1441        return 0;
1442
1443out_filesystem:
1444        unregister_filesystem(&mqueue_fs_type);
1445out_sysctl:
1446        if (mq_sysctl_table)
1447                unregister_sysctl_table(mq_sysctl_table);
1448        kmem_cache_destroy(mqueue_inode_cachep);
1449        return error;
1450}
1451
1452__initcall(init_mqueue_fs);
1453
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.