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#include <linux/sched/wake_q.h>
  39#include <linux/sched/signal.h>
  40#include <linux/sched/user.h>
  41
  42#include <net/sock.h>
  43#include "util.h"
  44
  45#define MQUEUE_MAGIC    0x19800202
  46#define DIRENT_SIZE     20
  47#define FILENT_SIZE     80
  48
  49#define SEND            0
  50#define RECV            1
  51
  52#define STATE_NONE      0
  53#define STATE_READY     1
  54
  55struct posix_msg_tree_node {
  56        struct rb_node          rb_node;
  57        struct list_head        msg_list;
  58        int                     priority;
  59};
  60
  61struct ext_wait_queue {         /* queue of sleeping tasks */
  62        struct task_struct *task;
  63        struct list_head list;
  64        struct msg_msg *msg;    /* ptr of loaded message */
  65        int state;              /* one of STATE_* values */
  66};
  67
  68struct mqueue_inode_info {
  69        spinlock_t lock;
  70        struct inode vfs_inode;
  71        wait_queue_head_t wait_q;
  72
  73        struct rb_root msg_tree;
  74        struct posix_msg_tree_node *node_cache;
  75        struct mq_attr attr;
  76
  77        struct sigevent notify;
  78        struct pid *notify_owner;
  79        struct user_namespace *notify_user_ns;
  80        struct user_struct *user;       /* user who created, for accounting */
  81        struct sock *notify_sock;
  82        struct sk_buff *notify_cookie;
  83
  84        /* for tasks waiting for free space and messages, respectively */
  85        struct ext_wait_queue e_wait_q[2];
  86
  87        unsigned long qsize; /* size of queue in memory (sum of all msgs) */
  88};
  89
  90static const struct inode_operations mqueue_dir_inode_operations;
  91static const struct file_operations mqueue_file_operations;
  92static const struct super_operations mqueue_super_ops;
  93static void remove_notification(struct mqueue_inode_info *info);
  94
  95static struct kmem_cache *mqueue_inode_cachep;
  96
  97static struct ctl_table_header *mq_sysctl_table;
  98
  99static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
 100{
 101        return container_of(inode, struct mqueue_inode_info, vfs_inode);
 102}
 103
 104/*
 105 * This routine should be called with the mq_lock held.
 106 */
 107static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
 108{
 109        return get_ipc_ns(inode->i_sb->s_fs_info);
 110}
 111
 112static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
 113{
 114        struct ipc_namespace *ns;
 115
 116        spin_lock(&mq_lock);
 117        ns = __get_ns_from_inode(inode);
 118        spin_unlock(&mq_lock);
 119        return ns;
 120}
 121
 122/* Auxiliary functions to manipulate messages' list */
 123static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
 124{
 125        struct rb_node **p, *parent = NULL;
 126        struct posix_msg_tree_node *leaf;
 127
 128        p = &info->msg_tree.rb_node;
 129        while (*p) {
 130                parent = *p;
 131                leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
 132
 133                if (likely(leaf->priority == msg->m_type))
 134                        goto insert_msg;
 135                else if (msg->m_type < leaf->priority)
 136                        p = &(*p)->rb_left;
 137                else
 138                        p = &(*p)->rb_right;
 139        }
 140        if (info->node_cache) {
 141                leaf = info->node_cache;
 142                info->node_cache = NULL;
 143        } else {
 144                leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
 145                if (!leaf)
 146                        return -ENOMEM;
 147                INIT_LIST_HEAD(&leaf->msg_list);
 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                        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                                kfree(leaf);
 205                        } else {
 206                                info->node_cache = leaf;
 207                        }
 208                }
 209        }
 210        info->attr.mq_curmsgs--;
 211        info->qsize -= msg->m_ts;
 212        return msg;
 213}
 214
 215static struct inode *mqueue_get_inode(struct super_block *sb,
 216                struct ipc_namespace *ipc_ns, umode_t mode,
 217                struct mq_attr *attr)
 218{
 219        struct user_struct *u = current_user();
 220        struct inode *inode;
 221        int ret = -ENOMEM;
 222
 223        inode = new_inode(sb);
 224        if (!inode)
 225                goto err;
 226
 227        inode->i_ino = get_next_ino();
 228        inode->i_mode = mode;
 229        inode->i_uid = current_fsuid();
 230        inode->i_gid = current_fsgid();
 231        inode->i_mtime = inode->i_ctime = inode->i_atime = current_time(inode);
 232
 233        if (S_ISREG(mode)) {
 234                struct mqueue_inode_info *info;
 235                unsigned long mq_bytes, mq_treesize;
 236
 237                inode->i_fop = &mqueue_file_operations;
 238                inode->i_size = FILENT_SIZE;
 239                /* mqueue specific info */
 240                info = MQUEUE_I(inode);
 241                spin_lock_init(&info->lock);
 242                init_waitqueue_head(&info->wait_q);
 243                INIT_LIST_HEAD(&info->e_wait_q[0].list);
 244                INIT_LIST_HEAD(&info->e_wait_q[1].list);
 245                info->notify_owner = NULL;
 246                info->notify_user_ns = NULL;
 247                info->qsize = 0;
 248                info->user = NULL;      /* set when all is ok */
 249                info->msg_tree = RB_ROOT;
 250                info->node_cache = NULL;
 251                memset(&info->attr, 0, sizeof(info->attr));
 252                info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
 253                                           ipc_ns->mq_msg_default);
 254                info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
 255                                            ipc_ns->mq_msgsize_default);
 256                if (attr) {
 257                        info->attr.mq_maxmsg = attr->mq_maxmsg;
 258                        info->attr.mq_msgsize = attr->mq_msgsize;
 259                }
 260                /*
 261                 * We used to allocate a static array of pointers and account
 262                 * the size of that array as well as one msg_msg struct per
 263                 * possible message into the queue size. That's no longer
 264                 * accurate as the queue is now an rbtree and will grow and
 265                 * shrink depending on usage patterns.  We can, however, still
 266                 * account one msg_msg struct per message, but the nodes are
 267                 * allocated depending on priority usage, and most programs
 268                 * only use one, or a handful, of priorities.  However, since
 269                 * this is pinned memory, we need to assume worst case, so
 270                 * that means the min(mq_maxmsg, max_priorities) * struct
 271                 * posix_msg_tree_node.
 272                 */
 273
 274                ret = -EINVAL;
 275                if (info->attr.mq_maxmsg <= 0 || info->attr.mq_msgsize <= 0)
 276                        goto out_inode;
 277                if (capable(CAP_SYS_RESOURCE)) {
 278                        if (info->attr.mq_maxmsg > HARD_MSGMAX ||
 279                            info->attr.mq_msgsize > HARD_MSGSIZEMAX)
 280                                goto out_inode;
 281                } else {
 282                        if (info->attr.mq_maxmsg > ipc_ns->mq_msg_max ||
 283                                        info->attr.mq_msgsize > ipc_ns->mq_msgsize_max)
 284                                goto out_inode;
 285                }
 286                ret = -EOVERFLOW;
 287                /* check for overflow */
 288                if (info->attr.mq_msgsize > ULONG_MAX/info->attr.mq_maxmsg)
 289                        goto out_inode;
 290                mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
 291                        min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
 292                        sizeof(struct posix_msg_tree_node);
 293                mq_bytes = info->attr.mq_maxmsg * info->attr.mq_msgsize;
 294                if (mq_bytes + mq_treesize < mq_bytes)
 295                        goto out_inode;
 296                mq_bytes += mq_treesize;
 297                spin_lock(&mq_lock);
 298                if (u->mq_bytes + mq_bytes < u->mq_bytes ||
 299                    u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
 300                        spin_unlock(&mq_lock);
 301                        /* mqueue_evict_inode() releases info->messages */
 302                        ret = -EMFILE;
 303                        goto out_inode;
 304                }
 305                u->mq_bytes += mq_bytes;
 306                spin_unlock(&mq_lock);
 307
 308                /* all is ok */
 309                info->user = get_uid(u);
 310        } else if (S_ISDIR(mode)) {
 311                inc_nlink(inode);
 312                /* Some things misbehave if size == 0 on a directory */
 313                inode->i_size = 2 * DIRENT_SIZE;
 314                inode->i_op = &mqueue_dir_inode_operations;
 315                inode->i_fop = &simple_dir_operations;
 316        }
 317
 318        return inode;
 319out_inode:
 320        iput(inode);
 321err:
 322        return ERR_PTR(ret);
 323}
 324
 325static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
 326{
 327        struct inode *inode;
 328        struct ipc_namespace *ns = sb->s_fs_info;
 329
 330        sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
 331        sb->s_blocksize = PAGE_SIZE;
 332        sb->s_blocksize_bits = PAGE_SHIFT;
 333        sb->s_magic = MQUEUE_MAGIC;
 334        sb->s_op = &mqueue_super_ops;
 335
 336        inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
 337        if (IS_ERR(inode))
 338                return PTR_ERR(inode);
 339
 340        sb->s_root = d_make_root(inode);
 341        if (!sb->s_root)
 342                return -ENOMEM;
 343        return 0;
 344}
 345
 346static struct dentry *mqueue_mount(struct file_system_type *fs_type,
 347                         int flags, const char *dev_name,
 348                         void *data)
 349{
 350        struct ipc_namespace *ns;
 351        if (flags & SB_KERNMOUNT) {
 352                ns = data;
 353                data = NULL;
 354        } else {
 355                ns = current->nsproxy->ipc_ns;
 356        }
 357        return mount_ns(fs_type, flags, data, ns, ns->user_ns, mqueue_fill_super);
 358}
 359
 360static void init_once(void *foo)
 361{
 362        struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
 363
 364        inode_init_once(&p->vfs_inode);
 365}
 366
 367static struct inode *mqueue_alloc_inode(struct super_block *sb)
 368{
 369        struct mqueue_inode_info *ei;
 370
 371        ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
 372        if (!ei)
 373                return NULL;
 374        return &ei->vfs_inode;
 375}
 376
 377static void mqueue_i_callback(struct rcu_head *head)
 378{
 379        struct inode *inode = container_of(head, struct inode, i_rcu);
 380        kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
 381}
 382
 383static void mqueue_destroy_inode(struct inode *inode)
 384{
 385        call_rcu(&inode->i_rcu, mqueue_i_callback);
 386}
 387
 388static void mqueue_evict_inode(struct inode *inode)
 389{
 390        struct mqueue_inode_info *info;
 391        struct user_struct *user;
 392        unsigned long mq_bytes, mq_treesize;
 393        struct ipc_namespace *ipc_ns;
 394        struct msg_msg *msg;
 395
 396        clear_inode(inode);
 397
 398        if (S_ISDIR(inode->i_mode))
 399                return;
 400
 401        ipc_ns = get_ns_from_inode(inode);
 402        info = MQUEUE_I(inode);
 403        spin_lock(&info->lock);
 404        while ((msg = msg_get(info)) != NULL)
 405                free_msg(msg);
 406        kfree(info->node_cache);
 407        spin_unlock(&info->lock);
 408
 409        /* Total amount of bytes accounted for the mqueue */
 410        mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
 411                min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
 412                sizeof(struct posix_msg_tree_node);
 413
 414        mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
 415                                  info->attr.mq_msgsize);
 416
 417        user = info->user;
 418        if (user) {
 419                spin_lock(&mq_lock);
 420                user->mq_bytes -= mq_bytes;
 421                /*
 422                 * get_ns_from_inode() ensures that the
 423                 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
 424                 * to which we now hold a reference, or it is NULL.
 425                 * We can't put it here under mq_lock, though.
 426                 */
 427                if (ipc_ns)
 428                        ipc_ns->mq_queues_count--;
 429                spin_unlock(&mq_lock);
 430                free_uid(user);
 431        }
 432        if (ipc_ns)
 433                put_ipc_ns(ipc_ns);
 434}
 435
 436static int mqueue_create_attr(struct dentry *dentry, umode_t mode, void *arg)
 437{
 438        struct inode *dir = dentry->d_parent->d_inode;
 439        struct inode *inode;
 440        struct mq_attr *attr = arg;
 441        int error;
 442        struct ipc_namespace *ipc_ns;
 443
 444        spin_lock(&mq_lock);
 445        ipc_ns = __get_ns_from_inode(dir);
 446        if (!ipc_ns) {
 447                error = -EACCES;
 448                goto out_unlock;
 449        }
 450
 451        if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
 452            !capable(CAP_SYS_RESOURCE)) {
 453                error = -ENOSPC;
 454                goto out_unlock;
 455        }
 456        ipc_ns->mq_queues_count++;
 457        spin_unlock(&mq_lock);
 458
 459        inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
 460        if (IS_ERR(inode)) {
 461                error = PTR_ERR(inode);
 462                spin_lock(&mq_lock);
 463                ipc_ns->mq_queues_count--;
 464                goto out_unlock;
 465        }
 466
 467        put_ipc_ns(ipc_ns);
 468        dir->i_size += DIRENT_SIZE;
 469        dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
 470
 471        d_instantiate(dentry, inode);
 472        dget(dentry);
 473        return 0;
 474out_unlock:
 475        spin_unlock(&mq_lock);
 476        if (ipc_ns)
 477                put_ipc_ns(ipc_ns);
 478        return error;
 479}
 480
 481static int mqueue_create(struct inode *dir, struct dentry *dentry,
 482                                umode_t mode, bool excl)
 483{
 484        return mqueue_create_attr(dentry, mode, NULL);
 485}
 486
 487static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
 488{
 489        struct inode *inode = d_inode(dentry);
 490
 491        dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
 492        dir->i_size -= DIRENT_SIZE;
 493        drop_nlink(inode);
 494        dput(dentry);
 495        return 0;
 496}
 497
 498/*
 499*       This is routine for system read from queue file.
 500*       To avoid mess with doing here some sort of mq_receive we allow
 501*       to read only queue size & notification info (the only values
 502*       that are interesting from user point of view and aren't accessible
 503*       through std routines)
 504*/
 505static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
 506                                size_t count, loff_t *off)
 507{
 508        struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
 509        char buffer[FILENT_SIZE];
 510        ssize_t ret;
 511
 512        spin_lock(&info->lock);
 513        snprintf(buffer, sizeof(buffer),
 514                        "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
 515                        info->qsize,
 516                        info->notify_owner ? info->notify.sigev_notify : 0,
 517                        (info->notify_owner &&
 518                         info->notify.sigev_notify == SIGEV_SIGNAL) ?
 519                                info->notify.sigev_signo : 0,
 520                        pid_vnr(info->notify_owner));
 521        spin_unlock(&info->lock);
 522        buffer[sizeof(buffer)-1] = '\0';
 523
 524        ret = simple_read_from_buffer(u_data, count, off, buffer,
 525                                strlen(buffer));
 526        if (ret <= 0)
 527                return ret;
 528
 529        file_inode(filp)->i_atime = file_inode(filp)->i_ctime = current_time(file_inode(filp));
 530        return ret;
 531}
 532
 533static int mqueue_flush_file(struct file *filp, fl_owner_t id)
 534{
 535        struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
 536
 537        spin_lock(&info->lock);
 538        if (task_tgid(current) == info->notify_owner)
 539                remove_notification(info);
 540
 541        spin_unlock(&info->lock);
 542        return 0;
 543}
 544
 545static __poll_t mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
 546{
 547        struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
 548        __poll_t retval = 0;
 549
 550        poll_wait(filp, &info->wait_q, poll_tab);
 551
 552        spin_lock(&info->lock);
 553        if (info->attr.mq_curmsgs)
 554                retval = EPOLLIN | EPOLLRDNORM;
 555
 556        if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
 557                retval |= EPOLLOUT | EPOLLWRNORM;
 558        spin_unlock(&info->lock);
 559
 560        return retval;
 561}
 562
 563/* Adds current to info->e_wait_q[sr] before element with smaller prio */
 564static void wq_add(struct mqueue_inode_info *info, int sr,
 565                        struct ext_wait_queue *ewp)
 566{
 567        struct ext_wait_queue *walk;
 568
 569        ewp->task = current;
 570
 571        list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
 572                if (walk->task->prio <= current->prio) {
 573                        list_add_tail(&ewp->list, &walk->list);
 574                        return;
 575                }
 576        }
 577        list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
 578}
 579
 580/*
 581 * Puts current task to sleep. Caller must hold queue lock. After return
 582 * lock isn't held.
 583 * sr: SEND or RECV
 584 */
 585static int wq_sleep(struct mqueue_inode_info *info, int sr,
 586                    ktime_t *timeout, struct ext_wait_queue *ewp)
 587        __releases(&info->lock)
 588{
 589        int retval;
 590        signed long time;
 591
 592        wq_add(info, sr, ewp);
 593
 594        for (;;) {
 595                __set_current_state(TASK_INTERRUPTIBLE);
 596
 597                spin_unlock(&info->lock);
 598                time = schedule_hrtimeout_range_clock(timeout, 0,
 599                        HRTIMER_MODE_ABS, CLOCK_REALTIME);
 600
 601                if (ewp->state == STATE_READY) {
 602                        retval = 0;
 603                        goto out;
 604                }
 605                spin_lock(&info->lock);
 606                if (ewp->state == STATE_READY) {
 607                        retval = 0;
 608                        goto out_unlock;
 609                }
 610                if (signal_pending(current)) {
 611                        retval = -ERESTARTSYS;
 612                        break;
 613                }
 614                if (time == 0) {
 615                        retval = -ETIMEDOUT;
 616                        break;
 617                }
 618        }
 619        list_del(&ewp->list);
 620out_unlock:
 621        spin_unlock(&info->lock);
 622out:
 623        return retval;
 624}
 625
 626/*
 627 * Returns waiting task that should be serviced first or NULL if none exists
 628 */
 629static struct ext_wait_queue *wq_get_first_waiter(
 630                struct mqueue_inode_info *info, int sr)
 631{
 632        struct list_head *ptr;
 633
 634        ptr = info->e_wait_q[sr].list.prev;
 635        if (ptr == &info->e_wait_q[sr].list)
 636                return NULL;
 637        return list_entry(ptr, struct ext_wait_queue, list);
 638}
 639
 640
 641static inline void set_cookie(struct sk_buff *skb, char code)
 642{
 643        ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
 644}
 645
 646/*
 647 * The next function is only to split too long sys_mq_timedsend
 648 */
 649static void __do_notify(struct mqueue_inode_info *info)
 650{
 651        /* notification
 652         * invoked when there is registered process and there isn't process
 653         * waiting synchronously for message AND state of queue changed from
 654         * empty to not empty. Here we are sure that no one is waiting
 655         * synchronously. */
 656        if (info->notify_owner &&
 657            info->attr.mq_curmsgs == 1) {
 658                struct siginfo sig_i;
 659                switch (info->notify.sigev_notify) {
 660                case SIGEV_NONE:
 661                        break;
 662                case SIGEV_SIGNAL:
 663                        /* sends signal */
 664
 665                        clear_siginfo(&sig_i);
 666                        sig_i.si_signo = info->notify.sigev_signo;
 667                        sig_i.si_errno = 0;
 668                        sig_i.si_code = SI_MESGQ;
 669                        sig_i.si_value = info->notify.sigev_value;
 670                        /* map current pid/uid into info->owner's namespaces */
 671                        rcu_read_lock();
 672                        sig_i.si_pid = task_tgid_nr_ns(current,
 673                                                ns_of_pid(info->notify_owner));
 674                        sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
 675                        rcu_read_unlock();
 676
 677                        kill_pid_info(info->notify.sigev_signo,
 678                                      &sig_i, info->notify_owner);
 679                        break;
 680                case SIGEV_THREAD:
 681                        set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
 682                        netlink_sendskb(info->notify_sock, info->notify_cookie);
 683                        break;
 684                }
 685                /* after notification unregisters process */
 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        wake_up(&info->wait_q);
 692}
 693
 694static int prepare_timeout(const struct __kernel_timespec __user *u_abs_timeout,
 695                           struct timespec64 *ts)
 696{
 697        if (get_timespec64(ts, u_abs_timeout))
 698                return -EFAULT;
 699        if (!timespec64_valid(ts))
 700                return -EINVAL;
 701        return 0;
 702}
 703
 704static void remove_notification(struct mqueue_inode_info *info)
 705{
 706        if (info->notify_owner != NULL &&
 707            info->notify.sigev_notify == SIGEV_THREAD) {
 708                set_cookie(info->notify_cookie, NOTIFY_REMOVED);
 709                netlink_sendskb(info->notify_sock, info->notify_cookie);
 710        }
 711        put_pid(info->notify_owner);
 712        put_user_ns(info->notify_user_ns);
 713        info->notify_owner = NULL;
 714        info->notify_user_ns = NULL;
 715}
 716
 717static int prepare_open(struct dentry *dentry, int oflag, int ro,
 718                        umode_t mode, struct filename *name,
 719                        struct mq_attr *attr)
 720{
 721        static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
 722                                                  MAY_READ | MAY_WRITE };
 723        int acc;
 724
 725        if (d_really_is_negative(dentry)) {
 726                if (!(oflag & O_CREAT))
 727                        return -ENOENT;
 728                if (ro)
 729                        return ro;
 730                audit_inode_parent_hidden(name, dentry->d_parent);
 731                return vfs_mkobj(dentry, mode & ~current_umask(),
 732                                  mqueue_create_attr, attr);
 733        }
 734        /* it already existed */
 735        audit_inode(name, dentry, 0);
 736        if ((oflag & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))
 737                return -EEXIST;
 738        if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
 739                return -EINVAL;
 740        acc = oflag2acc[oflag & O_ACCMODE];
 741        return inode_permission(d_inode(dentry), acc);
 742}
 743
 744static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,
 745                      struct mq_attr *attr)
 746{
 747        struct vfsmount *mnt = current->nsproxy->ipc_ns->mq_mnt;
 748        struct dentry *root = mnt->mnt_root;
 749        struct filename *name;
 750        struct path path;
 751        int fd, error;
 752        int ro;
 753
 754        audit_mq_open(oflag, mode, attr);
 755
 756        if (IS_ERR(name = getname(u_name)))
 757                return PTR_ERR(name);
 758
 759        fd = get_unused_fd_flags(O_CLOEXEC);
 760        if (fd < 0)
 761                goto out_putname;
 762
 763        ro = mnt_want_write(mnt);       /* we'll drop it in any case */
 764        inode_lock(d_inode(root));
 765        path.dentry = lookup_one_len(name->name, root, strlen(name->name));
 766        if (IS_ERR(path.dentry)) {
 767                error = PTR_ERR(path.dentry);
 768                goto out_putfd;
 769        }
 770        path.mnt = mntget(mnt);
 771        error = prepare_open(path.dentry, oflag, ro, mode, name, attr);
 772        if (!error) {
 773                struct file *file = dentry_open(&path, oflag, current_cred());
 774                if (!IS_ERR(file))
 775                        fd_install(fd, file);
 776                else
 777                        error = PTR_ERR(file);
 778        }
 779        path_put(&path);
 780out_putfd:
 781        if (error) {
 782                put_unused_fd(fd);
 783                fd = error;
 784        }
 785        inode_unlock(d_inode(root));
 786        if (!ro)
 787                mnt_drop_write(mnt);
 788out_putname:
 789        putname(name);
 790        return fd;
 791}
 792
 793SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
 794                struct mq_attr __user *, u_attr)
 795{
 796        struct mq_attr attr;
 797        if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
 798                return -EFAULT;
 799
 800        return do_mq_open(u_name, oflag, mode, u_attr ? &attr : NULL);
 801}
 802
 803SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
 804{
 805        int err;
 806        struct filename *name;
 807        struct dentry *dentry;
 808        struct inode *inode = NULL;
 809        struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
 810        struct vfsmount *mnt = ipc_ns->mq_mnt;
 811
 812        name = getname(u_name);
 813        if (IS_ERR(name))
 814                return PTR_ERR(name);
 815
 816        audit_inode_parent_hidden(name, mnt->mnt_root);
 817        err = mnt_want_write(mnt);
 818        if (err)
 819                goto out_name;
 820        inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT);
 821        dentry = lookup_one_len(name->name, mnt->mnt_root,
 822                                strlen(name->name));
 823        if (IS_ERR(dentry)) {
 824                err = PTR_ERR(dentry);
 825                goto out_unlock;
 826        }
 827
 828        inode = d_inode(dentry);
 829        if (!inode) {
 830                err = -ENOENT;
 831        } else {
 832                ihold(inode);
 833                err = vfs_unlink(d_inode(dentry->d_parent), dentry, NULL);
 834        }
 835        dput(dentry);
 836
 837out_unlock:
 838        inode_unlock(d_inode(mnt->mnt_root));
 839        if (inode)
 840                iput(inode);
 841        mnt_drop_write(mnt);
 842out_name:
 843        putname(name);
 844
 845        return err;
 846}
 847
 848/* Pipelined send and receive functions.
 849 *
 850 * If a receiver finds no waiting message, then it registers itself in the
 851 * list of waiting receivers. A sender checks that list before adding the new
 852 * message into the message array. If there is a waiting receiver, then it
 853 * bypasses the message array and directly hands the message over to the
 854 * receiver. The receiver accepts the message and returns without grabbing the
 855 * queue spinlock:
 856 *
 857 * - Set pointer to message.
 858 * - Queue the receiver task for later wakeup (without the info->lock).
 859 * - Update its state to STATE_READY. Now the receiver can continue.
 860 * - Wake up the process after the lock is dropped. Should the process wake up
 861 *   before this wakeup (due to a timeout or a signal) it will either see
 862 *   STATE_READY and continue or acquire the lock to check the state again.
 863 *
 864 * The same algorithm is used for senders.
 865 */
 866
 867/* pipelined_send() - send a message directly to the task waiting in
 868 * sys_mq_timedreceive() (without inserting message into a queue).
 869 */
 870static inline void pipelined_send(struct wake_q_head *wake_q,
 871                                  struct mqueue_inode_info *info,
 872                                  struct msg_msg *message,
 873                                  struct ext_wait_queue *receiver)
 874{
 875        receiver->msg = message;
 876        list_del(&receiver->list);
 877        wake_q_add(wake_q, receiver->task);
 878        /*
 879         * Rely on the implicit cmpxchg barrier from wake_q_add such
 880         * that we can ensure that updating receiver->state is the last
 881         * write operation: As once set, the receiver can continue,
 882         * and if we don't have the reference count from the wake_q,
 883         * yet, at that point we can later have a use-after-free
 884         * condition and bogus wakeup.
 885         */
 886        receiver->state = STATE_READY;
 887}
 888
 889/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
 890 * gets its message and put to the queue (we have one free place for sure). */
 891static inline void pipelined_receive(struct wake_q_head *wake_q,
 892                                     struct mqueue_inode_info *info)
 893{
 894        struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
 895
 896        if (!sender) {
 897                /* for poll */
 898                wake_up_interruptible(&info->wait_q);
 899                return;
 900        }
 901        if (msg_insert(sender->msg, info))
 902                return;
 903
 904        list_del(&sender->list);
 905        wake_q_add(wake_q, sender->task);
 906        sender->state = STATE_READY;
 907}
 908
 909static int do_mq_timedsend(mqd_t mqdes, const char __user *u_msg_ptr,
 910                size_t msg_len, unsigned int msg_prio,
 911                struct timespec64 *ts)
 912{
 913        struct fd f;
 914        struct inode *inode;
 915        struct ext_wait_queue wait;
 916        struct ext_wait_queue *receiver;
 917        struct msg_msg *msg_ptr;
 918        struct mqueue_inode_info *info;
 919        ktime_t expires, *timeout = NULL;
 920        struct posix_msg_tree_node *new_leaf = NULL;
 921        int ret = 0;
 922        DEFINE_WAKE_Q(wake_q);
 923
 924        if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
 925                return -EINVAL;
 926
 927        if (ts) {
 928                expires = timespec64_to_ktime(*ts);
 929                timeout = &expires;
 930        }
 931
 932        audit_mq_sendrecv(mqdes, msg_len, msg_prio, ts);
 933
 934        f = fdget(mqdes);
 935        if (unlikely(!f.file)) {
 936                ret = -EBADF;
 937                goto out;
 938        }
 939
 940        inode = file_inode(f.file);
 941        if (unlikely(f.file->f_op != &mqueue_file_operations)) {
 942                ret = -EBADF;
 943                goto out_fput;
 944        }
 945        info = MQUEUE_I(inode);
 946        audit_file(f.file);
 947
 948        if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
 949                ret = -EBADF;
 950                goto out_fput;
 951        }
 952
 953        if (unlikely(msg_len > info->attr.mq_msgsize)) {
 954                ret = -EMSGSIZE;
 955                goto out_fput;
 956        }
 957
 958        /* First try to allocate memory, before doing anything with
 959         * existing queues. */
 960        msg_ptr = load_msg(u_msg_ptr, msg_len);
 961        if (IS_ERR(msg_ptr)) {
 962                ret = PTR_ERR(msg_ptr);
 963                goto out_fput;
 964        }
 965        msg_ptr->m_ts = msg_len;
 966        msg_ptr->m_type = msg_prio;
 967
 968        /*
 969         * msg_insert really wants us to have a valid, spare node struct so
 970         * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
 971         * fall back to that if necessary.
 972         */
 973        if (!info->node_cache)
 974                new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
 975
 976        spin_lock(&info->lock);
 977
 978        if (!info->node_cache && new_leaf) {
 979                /* Save our speculative allocation into the cache */
 980                INIT_LIST_HEAD(&new_leaf->msg_list);
 981                info->node_cache = new_leaf;
 982                new_leaf = NULL;
 983        } else {
 984                kfree(new_leaf);
 985        }
 986
 987        if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
 988                if (f.file->f_flags & O_NONBLOCK) {
 989                        ret = -EAGAIN;
 990                } else {
 991                        wait.task = current;
 992                        wait.msg = (void *) msg_ptr;
 993                        wait.state = STATE_NONE;
 994                        ret = wq_sleep(info, SEND, timeout, &wait);
 995                        /*
 996                         * wq_sleep must be called with info->lock held, and
 997                         * returns with the lock released
 998                         */
 999                        goto out_free;
1000                }
1001        } else {
1002                receiver = wq_get_first_waiter(info, RECV);
1003                if (receiver) {
1004                        pipelined_send(&wake_q, info, msg_ptr, receiver);
1005                } else {
1006                        /* adds message to the queue */
1007                        ret = msg_insert(msg_ptr, info);
1008                        if (ret)
1009                                goto out_unlock;
1010                        __do_notify(info);
1011                }
1012                inode->i_atime = inode->i_mtime = inode->i_ctime =
1013                                current_time(inode);
1014        }
1015out_unlock:
1016        spin_unlock(&info->lock);
1017        wake_up_q(&wake_q);
1018out_free:
1019        if (ret)
1020                free_msg(msg_ptr);
1021out_fput:
1022        fdput(f);
1023out:
1024        return ret;
1025}
1026
1027static int do_mq_timedreceive(mqd_t mqdes, char __user *u_msg_ptr,
1028                size_t msg_len, unsigned int __user *u_msg_prio,
1029                struct timespec64 *ts)
1030{
1031        ssize_t ret;
1032        struct msg_msg *msg_ptr;
1033        struct fd f;
1034        struct inode *inode;
1035        struct mqueue_inode_info *info;
1036        struct ext_wait_queue wait;
1037        ktime_t expires, *timeout = NULL;
1038        struct posix_msg_tree_node *new_leaf = NULL;
1039
1040        if (ts) {
1041                expires = timespec64_to_ktime(*ts);
1042                timeout = &expires;
1043        }
1044
1045        audit_mq_sendrecv(mqdes, msg_len, 0, ts);
1046
1047        f = fdget(mqdes);
1048        if (unlikely(!f.file)) {
1049                ret = -EBADF;
1050                goto out;
1051        }
1052
1053        inode = file_inode(f.file);
1054        if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1055                ret = -EBADF;
1056                goto out_fput;
1057        }
1058        info = MQUEUE_I(inode);
1059        audit_file(f.file);
1060
1061        if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1062                ret = -EBADF;
1063                goto out_fput;
1064        }
1065
1066        /* checks if buffer is big enough */
1067        if (unlikely(msg_len < info->attr.mq_msgsize)) {
1068                ret = -EMSGSIZE;
1069                goto out_fput;
1070        }
1071
1072        /*
1073         * msg_insert really wants us to have a valid, spare node struct so
1074         * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1075         * fall back to that if necessary.
1076         */
1077        if (!info->node_cache)
1078                new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1079
1080        spin_lock(&info->lock);
1081
1082        if (!info->node_cache && new_leaf) {
1083                /* Save our speculative allocation into the cache */
1084                INIT_LIST_HEAD(&new_leaf->msg_list);
1085                info->node_cache = new_leaf;
1086        } else {
1087                kfree(new_leaf);
1088        }
1089
1090        if (info->attr.mq_curmsgs == 0) {
1091                if (f.file->f_flags & O_NONBLOCK) {
1092                        spin_unlock(&info->lock);
1093                        ret = -EAGAIN;
1094                } else {
1095                        wait.task = current;
1096                        wait.state = STATE_NONE;
1097                        ret = wq_sleep(info, RECV, timeout, &wait);
1098                        msg_ptr = wait.msg;
1099                }
1100        } else {
1101                DEFINE_WAKE_Q(wake_q);
1102
1103                msg_ptr = msg_get(info);
1104
1105                inode->i_atime = inode->i_mtime = inode->i_ctime =
1106                                current_time(inode);
1107
1108                /* There is now free space in queue. */
1109                pipelined_receive(&wake_q, info);
1110                spin_unlock(&info->lock);
1111                wake_up_q(&wake_q);
1112                ret = 0;
1113        }
1114        if (ret == 0) {
1115                ret = msg_ptr->m_ts;
1116
1117                if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1118                        store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1119                        ret = -EFAULT;
1120                }
1121                free_msg(msg_ptr);
1122        }
1123out_fput:
1124        fdput(f);
1125out:
1126        return ret;
1127}
1128
1129SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
1130                size_t, msg_len, unsigned int, msg_prio,
1131                const struct __kernel_timespec __user *, u_abs_timeout)
1132{
1133        struct timespec64 ts, *p = NULL;
1134        if (u_abs_timeout) {
1135                int res = prepare_timeout(u_abs_timeout, &ts);
1136                if (res)
1137                        return res;
1138                p = &ts;
1139        }
1140        return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1141}
1142
1143SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1144                size_t, msg_len, unsigned int __user *, u_msg_prio,
1145                const struct __kernel_timespec __user *, u_abs_timeout)
1146{
1147        struct timespec64 ts, *p = NULL;
1148        if (u_abs_timeout) {
1149                int res = prepare_timeout(u_abs_timeout, &ts);
1150                if (res)
1151                        return res;
1152                p = &ts;
1153        }
1154        return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1155}
1156
1157/*
1158 * Notes: the case when user wants us to deregister (with NULL as pointer)
1159 * and he isn't currently owner of notification, will be silently discarded.
1160 * It isn't explicitly defined in the POSIX.
1161 */
1162static int do_mq_notify(mqd_t mqdes, const struct sigevent *notification)
1163{
1164        int ret;
1165        struct fd f;
1166        struct sock *sock;
1167        struct inode *inode;
1168        struct mqueue_inode_info *info;
1169        struct sk_buff *nc;
1170
1171        audit_mq_notify(mqdes, notification);
1172
1173        nc = NULL;
1174        sock = NULL;
1175        if (notification != NULL) {
1176                if (unlikely(notification->sigev_notify != SIGEV_NONE &&
1177                             notification->sigev_notify != SIGEV_SIGNAL &&
1178                             notification->sigev_notify != SIGEV_THREAD))
1179                        return -EINVAL;
1180                if (notification->sigev_notify == SIGEV_SIGNAL &&
1181                        !valid_signal(notification->sigev_signo)) {
1182                        return -EINVAL;
1183                }
1184                if (notification->sigev_notify == SIGEV_THREAD) {
1185                        long timeo;
1186
1187                        /* create the notify skb */
1188                        nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1189                        if (!nc) {
1190                                ret = -ENOMEM;
1191                                goto out;
1192                        }
1193                        if (copy_from_user(nc->data,
1194                                        notification->sigev_value.sival_ptr,
1195                                        NOTIFY_COOKIE_LEN)) {
1196                                ret = -EFAULT;
1197                                goto out;
1198                        }
1199
1200                        /* TODO: add a header? */
1201                        skb_put(nc, NOTIFY_COOKIE_LEN);
1202                        /* and attach it to the socket */
1203retry:
1204                        f = fdget(notification->sigev_signo);
1205                        if (!f.file) {
1206                                ret = -EBADF;
1207                                goto out;
1208                        }
1209                        sock = netlink_getsockbyfilp(f.file);
1210                        fdput(f);
1211                        if (IS_ERR(sock)) {
1212                                ret = PTR_ERR(sock);
1213                                sock = NULL;
1214                                goto out;
1215                        }
1216
1217                        timeo = MAX_SCHEDULE_TIMEOUT;
1218                        ret = netlink_attachskb(sock, nc, &timeo, NULL);
1219                        if (ret == 1) {
1220                                sock = NULL;
1221                                goto retry;
1222                        }
1223                        if (ret) {
1224                                sock = NULL;
1225                                nc = NULL;
1226                                goto out;
1227                        }
1228                }
1229        }
1230
1231        f = fdget(mqdes);
1232        if (!f.file) {
1233                ret = -EBADF;
1234                goto out;
1235        }
1236
1237        inode = file_inode(f.file);
1238        if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1239                ret = -EBADF;
1240                goto out_fput;
1241        }
1242        info = MQUEUE_I(inode);
1243
1244        ret = 0;
1245        spin_lock(&info->lock);
1246        if (notification == NULL) {
1247                if (info->notify_owner == task_tgid(current)) {
1248                        remove_notification(info);
1249                        inode->i_atime = inode->i_ctime = current_time(inode);
1250                }
1251        } else if (info->notify_owner != NULL) {
1252                ret = -EBUSY;
1253        } else {
1254                switch (notification->sigev_notify) {
1255                case SIGEV_NONE:
1256                        info->notify.sigev_notify = SIGEV_NONE;
1257                        break;
1258                case SIGEV_THREAD:
1259                        info->notify_sock = sock;
1260                        info->notify_cookie = nc;
1261                        sock = NULL;
1262                        nc = NULL;
1263                        info->notify.sigev_notify = SIGEV_THREAD;
1264                        break;
1265                case SIGEV_SIGNAL:
1266                        info->notify.sigev_signo = notification->sigev_signo;
1267                        info->notify.sigev_value = notification->sigev_value;
1268                        info->notify.sigev_notify = SIGEV_SIGNAL;
1269                        break;
1270                }
1271
1272                info->notify_owner = get_pid(task_tgid(current));
1273                info->notify_user_ns = get_user_ns(current_user_ns());
1274                inode->i_atime = inode->i_ctime = current_time(inode);
1275        }
1276        spin_unlock(&info->lock);
1277out_fput:
1278        fdput(f);
1279out:
1280        if (sock)
1281                netlink_detachskb(sock, nc);
1282        else if (nc)
1283                dev_kfree_skb(nc);
1284
1285        return ret;
1286}
1287
1288SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1289                const struct sigevent __user *, u_notification)
1290{
1291        struct sigevent n, *p = NULL;
1292        if (u_notification) {
1293                if (copy_from_user(&n, u_notification, sizeof(struct sigevent)))
1294                        return -EFAULT;
1295                p = &n;
1296        }
1297        return do_mq_notify(mqdes, p);
1298}
1299
1300static int do_mq_getsetattr(int mqdes, struct mq_attr *new, struct mq_attr *old)
1301{
1302        struct fd f;
1303        struct inode *inode;
1304        struct mqueue_inode_info *info;
1305
1306        if (new && (new->mq_flags & (~O_NONBLOCK)))
1307                return -EINVAL;
1308
1309        f = fdget(mqdes);
1310        if (!f.file)
1311                return -EBADF;
1312
1313        if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1314                fdput(f);
1315                return -EBADF;
1316        }
1317
1318        inode = file_inode(f.file);
1319        info = MQUEUE_I(inode);
1320
1321        spin_lock(&info->lock);
1322
1323        if (old) {
1324                *old = info->attr;
1325                old->mq_flags = f.file->f_flags & O_NONBLOCK;
1326        }
1327        if (new) {
1328                audit_mq_getsetattr(mqdes, new);
1329                spin_lock(&f.file->f_lock);
1330                if (new->mq_flags & O_NONBLOCK)
1331                        f.file->f_flags |= O_NONBLOCK;
1332                else
1333                        f.file->f_flags &= ~O_NONBLOCK;
1334                spin_unlock(&f.file->f_lock);
1335
1336                inode->i_atime = inode->i_ctime = current_time(inode);
1337        }
1338
1339        spin_unlock(&info->lock);
1340        fdput(f);
1341        return 0;
1342}
1343
1344SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1345                const struct mq_attr __user *, u_mqstat,
1346                struct mq_attr __user *, u_omqstat)
1347{
1348        int ret;
1349        struct mq_attr mqstat, omqstat;
1350        struct mq_attr *new = NULL, *old = NULL;
1351
1352        if (u_mqstat) {
1353                new = &mqstat;
1354                if (copy_from_user(new, u_mqstat, sizeof(struct mq_attr)))
1355                        return -EFAULT;
1356        }
1357        if (u_omqstat)
1358                old = &omqstat;
1359
1360        ret = do_mq_getsetattr(mqdes, new, old);
1361        if (ret || !old)
1362                return ret;
1363
1364        if (copy_to_user(u_omqstat, old, sizeof(struct mq_attr)))
1365                return -EFAULT;
1366        return 0;
1367}
1368
1369#ifdef CONFIG_COMPAT
1370
1371struct compat_mq_attr {
1372        compat_long_t mq_flags;      /* message queue flags                  */
1373        compat_long_t mq_maxmsg;     /* maximum number of messages           */
1374        compat_long_t mq_msgsize;    /* maximum message size                 */
1375        compat_long_t mq_curmsgs;    /* number of messages currently queued  */
1376        compat_long_t __reserved[4]; /* ignored for input, zeroed for output */
1377};
1378
1379static inline int get_compat_mq_attr(struct mq_attr *attr,
1380                        const struct compat_mq_attr __user *uattr)
1381{
1382        struct compat_mq_attr v;
1383
1384        if (copy_from_user(&v, uattr, sizeof(*uattr)))
1385                return -EFAULT;
1386
1387        memset(attr, 0, sizeof(*attr));
1388        attr->mq_flags = v.mq_flags;
1389        attr->mq_maxmsg = v.mq_maxmsg;
1390        attr->mq_msgsize = v.mq_msgsize;
1391        attr->mq_curmsgs = v.mq_curmsgs;
1392        return 0;
1393}
1394
1395static inline int put_compat_mq_attr(const struct mq_attr *attr,
1396                        struct compat_mq_attr __user *uattr)
1397{
1398        struct compat_mq_attr v;
1399
1400        memset(&v, 0, sizeof(v));
1401        v.mq_flags = attr->mq_flags;
1402        v.mq_maxmsg = attr->mq_maxmsg;
1403        v.mq_msgsize = attr->mq_msgsize;
1404        v.mq_curmsgs = attr->mq_curmsgs;
1405        if (copy_to_user(uattr, &v, sizeof(*uattr)))
1406                return -EFAULT;
1407        return 0;
1408}
1409
1410COMPAT_SYSCALL_DEFINE4(mq_open, const char __user *, u_name,
1411                       int, oflag, compat_mode_t, mode,
1412                       struct compat_mq_attr __user *, u_attr)
1413{
1414        struct mq_attr attr, *p = NULL;
1415        if (u_attr && oflag & O_CREAT) {
1416                p = &attr;
1417                if (get_compat_mq_attr(&attr, u_attr))
1418                        return -EFAULT;
1419        }
1420        return do_mq_open(u_name, oflag, mode, p);
1421}
1422
1423COMPAT_SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1424                       const struct compat_sigevent __user *, u_notification)
1425{
1426        struct sigevent n, *p = NULL;
1427        if (u_notification) {
1428                if (get_compat_sigevent(&n, u_notification))
1429                        return -EFAULT;
1430                if (n.sigev_notify == SIGEV_THREAD)
1431                        n.sigev_value.sival_ptr = compat_ptr(n.sigev_value.sival_int);
1432                p = &n;
1433        }
1434        return do_mq_notify(mqdes, p);
1435}
1436
1437COMPAT_SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1438                       const struct compat_mq_attr __user *, u_mqstat,
1439                       struct compat_mq_attr __user *, u_omqstat)
1440{
1441        int ret;
1442        struct mq_attr mqstat, omqstat;
1443        struct mq_attr *new = NULL, *old = NULL;
1444
1445        if (u_mqstat) {
1446                new = &mqstat;
1447                if (get_compat_mq_attr(new, u_mqstat))
1448                        return -EFAULT;
1449        }
1450        if (u_omqstat)
1451                old = &omqstat;
1452
1453        ret = do_mq_getsetattr(mqdes, new, old);
1454        if (ret || !old)
1455                return ret;
1456
1457        if (put_compat_mq_attr(old, u_omqstat))
1458                return -EFAULT;
1459        return 0;
1460}
1461#endif
1462
1463#ifdef CONFIG_COMPAT_32BIT_TIME
1464static int compat_prepare_timeout(const struct compat_timespec __user *p,
1465                                   struct timespec64 *ts)
1466{
1467        if (compat_get_timespec64(ts, p))
1468                return -EFAULT;
1469        if (!timespec64_valid(ts))
1470                return -EINVAL;
1471        return 0;
1472}
1473
1474COMPAT_SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes,
1475                       const char __user *, u_msg_ptr,
1476                       compat_size_t, msg_len, unsigned int, msg_prio,
1477                       const struct compat_timespec __user *, u_abs_timeout)
1478{
1479        struct timespec64 ts, *p = NULL;
1480        if (u_abs_timeout) {
1481                int res = compat_prepare_timeout(u_abs_timeout, &ts);
1482                if (res)
1483                        return res;
1484                p = &ts;
1485        }
1486        return do_mq_timedsend(mqdes, u_msg_ptr, msg_len, msg_prio, p);
1487}
1488
1489COMPAT_SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes,
1490                       char __user *, u_msg_ptr,
1491                       compat_size_t, msg_len, unsigned int __user *, u_msg_prio,
1492                       const struct compat_timespec __user *, u_abs_timeout)
1493{
1494        struct timespec64 ts, *p = NULL;
1495        if (u_abs_timeout) {
1496                int res = compat_prepare_timeout(u_abs_timeout, &ts);
1497                if (res)
1498                        return res;
1499                p = &ts;
1500        }
1501        return do_mq_timedreceive(mqdes, u_msg_ptr, msg_len, u_msg_prio, p);
1502}
1503#endif
1504
1505static const struct inode_operations mqueue_dir_inode_operations = {
1506        .lookup = simple_lookup,
1507        .create = mqueue_create,
1508        .unlink = mqueue_unlink,
1509};
1510
1511static const struct file_operations mqueue_file_operations = {
1512        .flush = mqueue_flush_file,
1513        .poll = mqueue_poll_file,
1514        .read = mqueue_read_file,
1515        .llseek = default_llseek,
1516};
1517
1518static const struct super_operations mqueue_super_ops = {
1519        .alloc_inode = mqueue_alloc_inode,
1520        .destroy_inode = mqueue_destroy_inode,
1521        .evict_inode = mqueue_evict_inode,
1522        .statfs = simple_statfs,
1523};
1524
1525static struct file_system_type mqueue_fs_type = {
1526        .name = "mqueue",
1527        .mount = mqueue_mount,
1528        .kill_sb = kill_litter_super,
1529        .fs_flags = FS_USERNS_MOUNT,
1530};
1531
1532int mq_init_ns(struct ipc_namespace *ns)
1533{
1534        ns->mq_queues_count  = 0;
1535        ns->mq_queues_max    = DFLT_QUEUESMAX;
1536        ns->mq_msg_max       = DFLT_MSGMAX;
1537        ns->mq_msgsize_max   = DFLT_MSGSIZEMAX;
1538        ns->mq_msg_default   = DFLT_MSG;
1539        ns->mq_msgsize_default  = DFLT_MSGSIZE;
1540
1541        ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1542        if (IS_ERR(ns->mq_mnt)) {
1543                int err = PTR_ERR(ns->mq_mnt);
1544                ns->mq_mnt = NULL;
1545                return err;
1546        }
1547        return 0;
1548}
1549
1550void mq_clear_sbinfo(struct ipc_namespace *ns)
1551{
1552        ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1553}
1554
1555void mq_put_mnt(struct ipc_namespace *ns)
1556{
1557        kern_unmount(ns->mq_mnt);
1558}
1559
1560static int __init init_mqueue_fs(void)
1561{
1562        int error;
1563
1564        mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1565                                sizeof(struct mqueue_inode_info), 0,
1566                                SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, init_once);
1567        if (mqueue_inode_cachep == NULL)
1568                return -ENOMEM;
1569
1570        /* ignore failures - they are not fatal */
1571        mq_sysctl_table = mq_register_sysctl_table();
1572
1573        error = register_filesystem(&mqueue_fs_type);
1574        if (error)
1575                goto out_sysctl;
1576
1577        spin_lock_init(&mq_lock);
1578
1579        error = mq_init_ns(&init_ipc_ns);
1580        if (error)
1581                goto out_filesystem;
1582
1583        return 0;
1584
1585out_filesystem:
1586        unregister_filesystem(&mqueue_fs_type);
1587out_sysctl:
1588        if (mq_sysctl_table)
1589                unregister_sysctl_table(mq_sysctl_table);
1590        kmem_cache_destroy(mqueue_inode_cachep);
1591        return error;
1592}
1593
1594device_initcall(init_mqueue_fs);
1595