1/* 2 * POSIX message queues filesystem for Linux. 3 * 4 * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl) 5 * Michal Wronski (michal.wronski@gmail.com) 6 * 7 * Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com) 8 * Lockless receive & send, fd based notify: 9 * Manfred Spraul (manfred@colorfullife.com) 10 * 11 * Audit: George Wilson (ltcgcw@us.ibm.com) 12 * 13 * This file is released under the GPL. 14 */ 15 16#include <linux/capability.h> 17#include <linux/init.h> 18#include <linux/pagemap.h> 19#include <linux/file.h> 20#include <linux/mount.h> 21#include <linux/namei.h> 22#include <linux/sysctl.h> 23#include <linux/poll.h> 24#include <linux/mqueue.h> 25#include <linux/msg.h> 26#include <linux/skbuff.h> 27#include <linux/vmalloc.h> 28#include <linux/netlink.h> 29#include <linux/syscalls.h> 30#include <linux/audit.h> 31#include <linux/signal.h> 32#include <linux/mutex.h> 33#include <linux/nsproxy.h> 34#include <linux/pid.h> 35#include <linux/ipc_namespace.h> 36#include <linux/user_namespace.h> 37#include <linux/slab.h> 38 39#include <net/sock.h> 40#include "util.h" 41 42#define MQUEUE_MAGIC 0x19800202 43#define DIRENT_SIZE 20 44#define FILENT_SIZE 80 45 46#define SEND 0 47#define RECV 1 48 49#define STATE_NONE 0 50#define STATE_PENDING 1 51#define STATE_READY 2 52 53struct posix_msg_tree_node { 54 struct rb_node rb_node; 55 struct list_head msg_list; 56 int priority; 57}; 58 59struct ext_wait_queue { /* queue of sleeping tasks */ 60 struct task_struct *task; 61 struct list_head list; 62 struct msg_msg *msg; /* ptr of loaded message */ 63 int state; /* one of STATE_* values */ 64}; 65 66struct mqueue_inode_info { 67 spinlock_t lock; 68 struct inode vfs_inode; 69 wait_queue_head_t wait_q; 70 71 struct rb_root msg_tree; 72 struct posix_msg_tree_node *node_cache; 73 struct mq_attr attr; 74 75 struct sigevent notify; 76 struct pid *notify_owner; 77 struct user_namespace *notify_user_ns; 78 struct user_struct *user; /* user who created, for accounting */ 79 struct sock *notify_sock; 80 struct sk_buff *notify_cookie; 81 82 /* for tasks waiting for free space and messages, respectively */ 83 struct ext_wait_queue e_wait_q[2]; 84 85 unsigned long qsize; /* size of queue in memory (sum of all msgs) */ 86}; 87 88static const struct inode_operations mqueue_dir_inode_operations; 89static const struct file_operations mqueue_file_operations; 90static const struct super_operations mqueue_super_ops; 91static void remove_notification(struct mqueue_inode_info *info); 92 93static struct kmem_cache *mqueue_inode_cachep; 94 95static struct ctl_table_header *mq_sysctl_table; 96 97static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode) 98{ 99 return container_of(inode, struct mqueue_inode_info, vfs_inode); 100} 101 102/* 103 * This routine should be called with the mq_lock held. 104 */ 105static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode) 106{ 107 return get_ipc_ns(inode->i_sb->s_fs_info); 108} 109 110static struct ipc_namespace *get_ns_from_inode(struct inode *inode) 111{ 112 struct ipc_namespace *ns; 113 114 spin_lock(&mq_lock); 115 ns = __get_ns_from_inode(inode); 116 spin_unlock(&mq_lock); 117 return ns; 118} 119 120/* Auxiliary functions to manipulate messages' list */ 121static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info) 122{ 123 struct rb_node **p, *parent = NULL; 124 struct posix_msg_tree_node *leaf; 125 126 p = &info->msg_tree.rb_node; 127 while (*p) { 128 parent = *p; 129 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node); 130 131 if (likely(leaf->priority == msg->m_type)) 132 goto insert_msg; 133 else if (msg->m_type < leaf->priority) 134 p = &(*p)->rb_left; 135 else 136 p = &(*p)->rb_right; 137 } 138 if (info->node_cache) { 139 leaf = info->node_cache; 140 info->node_cache = NULL; 141 } else { 142 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC); 143 if (!leaf) 144 return -ENOMEM; 145 INIT_LIST_HEAD(&leaf->msg_list); 146 } 147 leaf->priority = msg->m_type; 148 rb_link_node(&leaf->rb_node, parent, p); 149 rb_insert_color(&leaf->rb_node, &info->msg_tree); 150insert_msg: 151 info->attr.mq_curmsgs++; 152 info->qsize += msg->m_ts; 153 list_add_tail(&msg->m_list, &leaf->msg_list); 154 return 0; 155} 156 157static inline struct msg_msg *msg_get(struct mqueue_inode_info *info) 158{ 159 struct rb_node **p, *parent = NULL; 160 struct posix_msg_tree_node *leaf; 161 struct msg_msg *msg; 162 163try_again: 164 p = &info->msg_tree.rb_node; 165 while (*p) { 166 parent = *p; 167 /* 168 * During insert, low priorities go to the left and high to the 169 * right. On receive, we want the highest priorities first, so 170 * walk all the way to the right. 171 */ 172 p = &(*p)->rb_right; 173 } 174 if (!parent) { 175 if (info->attr.mq_curmsgs) { 176 pr_warn_once("Inconsistency in POSIX message queue, " 177 "no tree element, but supposedly messages " 178 "should exist!\n"); 179 info->attr.mq_curmsgs = 0; 180 } 181 return NULL; 182 } 183 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node); 184 if (unlikely(list_empty(&leaf->msg_list))) { 185 pr_warn_once("Inconsistency in POSIX message queue, " 186 "empty leaf node but we haven't implemented " 187 "lazy leaf delete!\n"); 188 rb_erase(&leaf->rb_node, &info->msg_tree); 189 if (info->node_cache) { 190 kfree(leaf); 191 } else { 192 info->node_cache = leaf; 193 } 194 goto try_again; 195 } else { 196 msg = list_first_entry(&leaf->msg_list, 197 struct msg_msg, m_list); 198 list_del(&msg->m_list); 199 if (list_empty(&leaf->msg_list)) { 200 rb_erase(&leaf->rb_node, &info->msg_tree); 201 if (info->node_cache) { 202 kfree(leaf); 203 } else { 204 info->node_cache = leaf; 205 } 206 } 207 } 208 info->attr.mq_curmsgs--; 209 info->qsize -= msg->m_ts; 210 return msg; 211} 212 213static struct inode *mqueue_get_inode(struct super_block *sb, 214 struct ipc_namespace *ipc_ns, umode_t mode, 215 struct mq_attr *attr) 216{ 217 struct user_struct *u = current_user(); 218 struct inode *inode; 219 int ret = -ENOMEM; 220 221 inode = new_inode(sb); 222 if (!inode) 223 goto err; 224 225 inode->i_ino = get_next_ino(); 226 inode->i_mode = mode; 227 inode->i_uid = current_fsuid(); 228 inode->i_gid = current_fsgid(); 229 inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME; 230 231 if (S_ISREG(mode)) { 232 struct mqueue_inode_info *info; 233 unsigned long mq_bytes, mq_treesize; 234 235 inode->i_fop = &mqueue_file_operations; 236 inode->i_size = FILENT_SIZE; 237 /* mqueue specific info */ 238 info = MQUEUE_I(inode); 239 spin_lock_init(&info->lock); 240 init_waitqueue_head(&info->wait_q); 241 INIT_LIST_HEAD(&info->e_wait_q[0].list); 242 INIT_LIST_HEAD(&info->e_wait_q[1].list); 243 info->notify_owner = NULL; 244 info->notify_user_ns = NULL; 245 info->qsize = 0; 246 info->user = NULL; /* set when all is ok */ 247 info->msg_tree = RB_ROOT; 248 info->node_cache = NULL; 249 memset(&info->attr, 0, sizeof(info->attr)); 250 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max, 251 ipc_ns->mq_msg_default); 252 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max, 253 ipc_ns->mq_msgsize_default); 254 if (attr) { 255 info->attr.mq_maxmsg = attr->mq_maxmsg; 256 info->attr.mq_msgsize = attr->mq_msgsize; 257 } 258 /* 259 * We used to allocate a static array of pointers and account 260 * the size of that array as well as one msg_msg struct per 261 * possible message into the queue size. That's no longer 262 * accurate as the queue is now an rbtree and will grow and 263 * shrink depending on usage patterns. We can, however, still 264 * account one msg_msg struct per message, but the nodes are 265 * allocated depending on priority usage, and most programs 266 * only use one, or a handful, of priorities. However, since 267 * this is pinned memory, we need to assume worst case, so 268 * that means the min(mq_maxmsg, max_priorities) * struct 269 * posix_msg_tree_node. 270 */ 271 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) + 272 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) * 273 sizeof(struct posix_msg_tree_node); 274 275 mq_bytes = mq_treesize + (info->attr.mq_maxmsg * 276 info->attr.mq_msgsize); 277 278 spin_lock(&mq_lock); 279 if (u->mq_bytes + mq_bytes < u->mq_bytes || 280 u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) { 281 spin_unlock(&mq_lock); 282 /* mqueue_evict_inode() releases info->messages */ 283 ret = -EMFILE; 284 goto out_inode; 285 } 286 u->mq_bytes += mq_bytes; 287 spin_unlock(&mq_lock); 288 289 /* all is ok */ 290 info->user = get_uid(u); 291 } else if (S_ISDIR(mode)) { 292 inc_nlink(inode); 293 /* Some things misbehave if size == 0 on a directory */ 294 inode->i_size = 2 * DIRENT_SIZE; 295 inode->i_op = &mqueue_dir_inode_operations; 296 inode->i_fop = &simple_dir_operations; 297 } 298 299 return inode; 300out_inode: 301 iput(inode); 302err: 303 return ERR_PTR(ret); 304} 305 306static int mqueue_fill_super(struct super_block *sb, void *data, int silent) 307{ 308 struct inode *inode; 309 struct ipc_namespace *ns = data; 310 311 sb->s_blocksize = PAGE_CACHE_SIZE; 312 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 313 sb->s_magic = MQUEUE_MAGIC; 314 sb->s_op = &mqueue_super_ops; 315 316 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL); 317 if (IS_ERR(inode)) 318 return PTR_ERR(inode); 319 320 sb->s_root = d_make_root(inode); 321 if (!sb->s_root) 322 return -ENOMEM; 323 return 0; 324} 325 326static struct dentry *mqueue_mount(struct file_system_type *fs_type, 327 int flags, const char *dev_name, 328 void *data) 329{ 330 if (!(flags & MS_KERNMOUNT)) { 331 struct ipc_namespace *ns = current->nsproxy->ipc_ns; 332 /* Don't allow mounting unless the caller has CAP_SYS_ADMIN 333 * over the ipc namespace. 334 */ 335 if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN)) 336 return ERR_PTR(-EPERM); 337 338 data = ns; 339 } 340 return mount_ns(fs_type, flags, data, mqueue_fill_super); 341} 342 343static void init_once(void *foo) 344{ 345 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo; 346 347 inode_init_once(&p->vfs_inode); 348} 349 350static struct inode *mqueue_alloc_inode(struct super_block *sb) 351{ 352 struct mqueue_inode_info *ei; 353 354 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL); 355 if (!ei) 356 return NULL; 357 return &ei->vfs_inode; 358} 359 360static void mqueue_i_callback(struct rcu_head *head) 361{ 362 struct inode *inode = container_of(head, struct inode, i_rcu); 363 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode)); 364} 365 366static void mqueue_destroy_inode(struct inode *inode) 367{ 368 call_rcu(&inode->i_rcu, mqueue_i_callback); 369} 370 371static void mqueue_evict_inode(struct inode *inode) 372{ 373 struct mqueue_inode_info *info; 374 struct user_struct *user; 375 unsigned long mq_bytes, mq_treesize; 376 struct ipc_namespace *ipc_ns; 377 struct msg_msg *msg; 378 379 clear_inode(inode); 380 381 if (S_ISDIR(inode->i_mode)) 382 return; 383 384 ipc_ns = get_ns_from_inode(inode); 385 info = MQUEUE_I(inode); 386 spin_lock(&info->lock); 387 while ((msg = msg_get(info)) != NULL) 388 free_msg(msg); 389 kfree(info->node_cache); 390 spin_unlock(&info->lock); 391 392 /* Total amount of bytes accounted for the mqueue */ 393 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) + 394 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) * 395 sizeof(struct posix_msg_tree_node); 396 397 mq_bytes = mq_treesize + (info->attr.mq_maxmsg * 398 info->attr.mq_msgsize); 399 400 user = info->user; 401 if (user) { 402 spin_lock(&mq_lock); 403 user->mq_bytes -= mq_bytes; 404 /* 405 * get_ns_from_inode() ensures that the 406 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns 407 * to which we now hold a reference, or it is NULL. 408 * We can't put it here under mq_lock, though. 409 */ 410 if (ipc_ns) 411 ipc_ns->mq_queues_count--; 412 spin_unlock(&mq_lock); 413 free_uid(user); 414 } 415 if (ipc_ns) 416 put_ipc_ns(ipc_ns); 417} 418 419static int mqueue_create(struct inode *dir, struct dentry *dentry, 420 umode_t mode, bool excl) 421{ 422 struct inode *inode; 423 struct mq_attr *attr = dentry->d_fsdata; 424 int error; 425 struct ipc_namespace *ipc_ns; 426 427 spin_lock(&mq_lock); 428 ipc_ns = __get_ns_from_inode(dir); 429 if (!ipc_ns) { 430 error = -EACCES; 431 goto out_unlock; 432 } 433 434 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max && 435 !capable(CAP_SYS_RESOURCE)) { 436 error = -ENOSPC; 437 goto out_unlock; 438 } 439 ipc_ns->mq_queues_count++; 440 spin_unlock(&mq_lock); 441 442 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr); 443 if (IS_ERR(inode)) { 444 error = PTR_ERR(inode); 445 spin_lock(&mq_lock); 446 ipc_ns->mq_queues_count--; 447 goto out_unlock; 448 } 449 450 put_ipc_ns(ipc_ns); 451 dir->i_size += DIRENT_SIZE; 452 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME; 453 454 d_instantiate(dentry, inode); 455 dget(dentry); 456 return 0; 457out_unlock: 458 spin_unlock(&mq_lock); 459 if (ipc_ns) 460 put_ipc_ns(ipc_ns); 461 return error; 462} 463 464static int mqueue_unlink(struct inode *dir, struct dentry *dentry) 465{ 466 struct inode *inode = d_inode(dentry); 467 468 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME; 469 dir->i_size -= DIRENT_SIZE; 470 drop_nlink(inode); 471 dput(dentry); 472 return 0; 473} 474 475/* 476* This is routine for system read from queue file. 477* To avoid mess with doing here some sort of mq_receive we allow 478* to read only queue size & notification info (the only values 479* that are interesting from user point of view and aren't accessible 480* through std routines) 481*/ 482static ssize_t mqueue_read_file(struct file *filp, char __user *u_data, 483 size_t count, loff_t *off) 484{ 485 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp)); 486 char buffer[FILENT_SIZE]; 487 ssize_t ret; 488 489 spin_lock(&info->lock); 490 snprintf(buffer, sizeof(buffer), 491 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n", 492 info->qsize, 493 info->notify_owner ? info->notify.sigev_notify : 0, 494 (info->notify_owner && 495 info->notify.sigev_notify == SIGEV_SIGNAL) ? 496 info->notify.sigev_signo : 0, 497 pid_vnr(info->notify_owner)); 498 spin_unlock(&info->lock); 499 buffer[sizeof(buffer)-1] = '\0'; 500 501 ret = simple_read_from_buffer(u_data, count, off, buffer, 502 strlen(buffer)); 503 if (ret <= 0) 504 return ret; 505 506 file_inode(filp)->i_atime = file_inode(filp)->i_ctime = CURRENT_TIME; 507 return ret; 508} 509 510static int mqueue_flush_file(struct file *filp, fl_owner_t id) 511{ 512 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp)); 513 514 spin_lock(&info->lock); 515 if (task_tgid(current) == info->notify_owner) 516 remove_notification(info); 517 518 spin_unlock(&info->lock); 519 return 0; 520} 521 522static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab) 523{ 524 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp)); 525 int retval = 0; 526 527 poll_wait(filp, &info->wait_q, poll_tab); 528 529 spin_lock(&info->lock); 530 if (info->attr.mq_curmsgs) 531 retval = POLLIN | POLLRDNORM; 532 533 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg) 534 retval |= POLLOUT | POLLWRNORM; 535 spin_unlock(&info->lock); 536 537 return retval; 538} 539 540/* Adds current to info->e_wait_q[sr] before element with smaller prio */ 541static void wq_add(struct mqueue_inode_info *info, int sr, 542 struct ext_wait_queue *ewp) 543{ 544 struct ext_wait_queue *walk; 545 546 ewp->task = current; 547 548 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) { 549 if (walk->task->static_prio <= current->static_prio) { 550 list_add_tail(&ewp->list, &walk->list); 551 return; 552 } 553 } 554 list_add_tail(&ewp->list, &info->e_wait_q[sr].list); 555} 556 557/* 558 * Puts current task to sleep. Caller must hold queue lock. After return 559 * lock isn't held. 560 * sr: SEND or RECV 561 */ 562static int wq_sleep(struct mqueue_inode_info *info, int sr, 563 ktime_t *timeout, struct ext_wait_queue *ewp) 564{ 565 int retval; 566 signed long time; 567 568 wq_add(info, sr, ewp); 569 570 for (;;) { 571 set_current_state(TASK_INTERRUPTIBLE); 572 573 spin_unlock(&info->lock); 574 time = schedule_hrtimeout_range_clock(timeout, 0, 575 HRTIMER_MODE_ABS, CLOCK_REALTIME); 576 577 while (ewp->state == STATE_PENDING) 578 cpu_relax(); 579 580 if (ewp->state == STATE_READY) { 581 retval = 0; 582 goto out; 583 } 584 spin_lock(&info->lock); 585 if (ewp->state == STATE_READY) { 586 retval = 0; 587 goto out_unlock; 588 } 589 if (signal_pending(current)) { 590 retval = -ERESTARTSYS; 591 break; 592 } 593 if (time == 0) { 594 retval = -ETIMEDOUT; 595 break; 596 } 597 } 598 list_del(&ewp->list); 599out_unlock: 600 spin_unlock(&info->lock); 601out: 602 return retval; 603} 604 605/* 606 * Returns waiting task that should be serviced first or NULL if none exists 607 */ 608static struct ext_wait_queue *wq_get_first_waiter( 609 struct mqueue_inode_info *info, int sr) 610{ 611 struct list_head *ptr; 612 613 ptr = info->e_wait_q[sr].list.prev; 614 if (ptr == &info->e_wait_q[sr].list) 615 return NULL; 616 return list_entry(ptr, struct ext_wait_queue, list); 617} 618 619 620static inline void set_cookie(struct sk_buff *skb, char code) 621{ 622 ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code; 623} 624 625/* 626 * The next function is only to split too long sys_mq_timedsend 627 */ 628static void __do_notify(struct mqueue_inode_info *info) 629{ 630 /* notification 631 * invoked when there is registered process and there isn't process 632 * waiting synchronously for message AND state of queue changed from 633 * empty to not empty. Here we are sure that no one is waiting 634 * synchronously. */ 635 if (info->notify_owner && 636 info->attr.mq_curmsgs == 1) { 637 struct siginfo sig_i; 638 switch (info->notify.sigev_notify) { 639 case SIGEV_NONE: 640 break; 641 case SIGEV_SIGNAL: 642 /* sends signal */ 643 644 sig_i.si_signo = info->notify.sigev_signo; 645 sig_i.si_errno = 0; 646 sig_i.si_code = SI_MESGQ; 647 sig_i.si_value = info->notify.sigev_value; 648 /* map current pid/uid into info->owner's namespaces */ 649 rcu_read_lock(); 650 sig_i.si_pid = task_tgid_nr_ns(current, 651 ns_of_pid(info->notify_owner)); 652 sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid()); 653 rcu_read_unlock(); 654 655 kill_pid_info(info->notify.sigev_signo, 656 &sig_i, info->notify_owner); 657 break; 658 case SIGEV_THREAD: 659 set_cookie(info->notify_cookie, NOTIFY_WOKENUP); 660 netlink_sendskb(info->notify_sock, info->notify_cookie); 661 break; 662 } 663 /* after notification unregisters process */ 664 put_pid(info->notify_owner); 665 put_user_ns(info->notify_user_ns); 666 info->notify_owner = NULL; 667 info->notify_user_ns = NULL; 668 } 669 wake_up(&info->wait_q); 670} 671 672static int prepare_timeout(const struct timespec __user *u_abs_timeout, 673 ktime_t *expires, struct timespec *ts) 674{ 675 if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec))) 676 return -EFAULT; 677 if (!timespec_valid(ts)) 678 return -EINVAL; 679 680 *expires = timespec_to_ktime(*ts); 681 return 0; 682} 683 684static void remove_notification(struct mqueue_inode_info *info) 685{ 686 if (info->notify_owner != NULL && 687 info->notify.sigev_notify == SIGEV_THREAD) { 688 set_cookie(info->notify_cookie, NOTIFY_REMOVED); 689 netlink_sendskb(info->notify_sock, info->notify_cookie); 690 } 691 put_pid(info->notify_owner); 692 put_user_ns(info->notify_user_ns); 693 info->notify_owner = NULL; 694 info->notify_user_ns = NULL; 695} 696 697static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr) 698{ 699 int mq_treesize; 700 unsigned long total_size; 701 702 if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0) 703 return -EINVAL; 704 if (capable(CAP_SYS_RESOURCE)) { 705 if (attr->mq_maxmsg > HARD_MSGMAX || 706 attr->mq_msgsize > HARD_MSGSIZEMAX) 707 return -EINVAL; 708 } else { 709 if (attr->mq_maxmsg > ipc_ns->mq_msg_max || 710 attr->mq_msgsize > ipc_ns->mq_msgsize_max) 711 return -EINVAL; 712 } 713 /* check for overflow */ 714 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg) 715 return -EOVERFLOW; 716 mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) + 717 min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) * 718 sizeof(struct posix_msg_tree_node); 719 total_size = attr->mq_maxmsg * attr->mq_msgsize; 720 if (total_size + mq_treesize < total_size) 721 return -EOVERFLOW; 722 return 0; 723} 724 725/* 726 * Invoked when creating a new queue via sys_mq_open 727 */ 728static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir, 729 struct path *path, int oflag, umode_t mode, 730 struct mq_attr *attr) 731{ 732 const struct cred *cred = current_cred(); 733 int ret; 734 735 if (attr) { 736 ret = mq_attr_ok(ipc_ns, attr); 737 if (ret) 738 return ERR_PTR(ret); 739 /* store for use during create */ 740 path->dentry->d_fsdata = attr; 741 } else { 742 struct mq_attr def_attr; 743 744 def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max, 745 ipc_ns->mq_msg_default); 746 def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max, 747 ipc_ns->mq_msgsize_default); 748 ret = mq_attr_ok(ipc_ns, &def_attr); 749 if (ret) 750 return ERR_PTR(ret); 751 } 752 753 mode &= ~current_umask(); 754 ret = vfs_create(dir, path->dentry, mode, true); 755 path->dentry->d_fsdata = NULL; 756 if (ret) 757 return ERR_PTR(ret); 758 return dentry_open(path, oflag, cred); 759} 760 761/* Opens existing queue */ 762static struct file *do_open(struct path *path, int oflag) 763{ 764 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE, 765 MAY_READ | MAY_WRITE }; 766 int acc; 767 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) 768 return ERR_PTR(-EINVAL); 769 acc = oflag2acc[oflag & O_ACCMODE]; 770 if (inode_permission(d_inode(path->dentry), acc)) 771 return ERR_PTR(-EACCES); 772 return dentry_open(path, oflag, current_cred()); 773} 774 775SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode, 776 struct mq_attr __user *, u_attr) 777{ 778 struct path path; 779 struct file *filp; 780 struct filename *name; 781 struct mq_attr attr; 782 int fd, error; 783 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; 784 struct vfsmount *mnt = ipc_ns->mq_mnt; 785 struct dentry *root = mnt->mnt_root; 786 int ro; 787 788 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr))) 789 return -EFAULT; 790 791 audit_mq_open(oflag, mode, u_attr ? &attr : NULL); 792 793 if (IS_ERR(name = getname(u_name))) 794 return PTR_ERR(name); 795 796 fd = get_unused_fd_flags(O_CLOEXEC); 797 if (fd < 0) 798 goto out_putname; 799 800 ro = mnt_want_write(mnt); /* we'll drop it in any case */ 801 error = 0; 802 mutex_lock(&d_inode(root)->i_mutex); 803 path.dentry = lookup_one_len(name->name, root, strlen(name->name)); 804 if (IS_ERR(path.dentry)) { 805 error = PTR_ERR(path.dentry); 806 goto out_putfd; 807 } 808 path.mnt = mntget(mnt); 809 810 if (oflag & O_CREAT) { 811 if (d_really_is_positive(path.dentry)) { /* entry already exists */ 812 audit_inode(name, path.dentry, 0); 813 if (oflag & O_EXCL) { 814 error = -EEXIST; 815 goto out; 816 } 817 filp = do_open(&path, oflag); 818 } else { 819 if (ro) { 820 error = ro; 821 goto out; 822 } 823 audit_inode_parent_hidden(name, root); 824 filp = do_create(ipc_ns, d_inode(root), 825 &path, oflag, mode, 826 u_attr ? &attr : NULL); 827 } 828 } else { 829 if (d_really_is_negative(path.dentry)) { 830 error = -ENOENT; 831 goto out; 832 } 833 audit_inode(name, path.dentry, 0); 834 filp = do_open(&path, oflag); 835 } 836 837 if (!IS_ERR(filp)) 838 fd_install(fd, filp); 839 else 840 error = PTR_ERR(filp); 841out: 842 path_put(&path); 843out_putfd: 844 if (error) { 845 put_unused_fd(fd); 846 fd = error; 847 } 848 mutex_unlock(&d_inode(root)->i_mutex); 849 if (!ro) 850 mnt_drop_write(mnt); 851out_putname: 852 putname(name); 853 return fd; 854} 855 856SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name) 857{ 858 int err; 859 struct filename *name; 860 struct dentry *dentry; 861 struct inode *inode = NULL; 862 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; 863 struct vfsmount *mnt = ipc_ns->mq_mnt; 864 865 name = getname(u_name); 866 if (IS_ERR(name)) 867 return PTR_ERR(name); 868 869 audit_inode_parent_hidden(name, mnt->mnt_root); 870 err = mnt_want_write(mnt); 871 if (err) 872 goto out_name; 873 mutex_lock_nested(&d_inode(mnt->mnt_root)->i_mutex, I_MUTEX_PARENT); 874 dentry = lookup_one_len(name->name, mnt->mnt_root, 875 strlen(name->name)); 876 if (IS_ERR(dentry)) { 877 err = PTR_ERR(dentry); 878 goto out_unlock; 879 } 880 881 inode = d_inode(dentry); 882 if (!inode) { 883 err = -ENOENT; 884 } else { 885 ihold(inode); 886 err = vfs_unlink(d_inode(dentry->d_parent), dentry, NULL); 887 } 888 dput(dentry); 889 890out_unlock: 891 mutex_unlock(&d_inode(mnt->mnt_root)->i_mutex); 892 if (inode) 893 iput(inode); 894 mnt_drop_write(mnt); 895out_name: 896 putname(name); 897 898 return err; 899} 900 901/* Pipelined send and receive functions. 902 * 903 * If a receiver finds no waiting message, then it registers itself in the 904 * list of waiting receivers. A sender checks that list before adding the new 905 * message into the message array. If there is a waiting receiver, then it 906 * bypasses the message array and directly hands the message over to the 907 * receiver. 908 * The receiver accepts the message and returns without grabbing the queue 909 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers 910 * are necessary. The same algorithm is used for sysv semaphores, see 911 * ipc/sem.c for more details. 912 * 913 * The same algorithm is used for senders. 914 */ 915 916/* pipelined_send() - send a message directly to the task waiting in 917 * sys_mq_timedreceive() (without inserting message into a queue). 918 */ 919static inline void pipelined_send(struct mqueue_inode_info *info, 920 struct msg_msg *message, 921 struct ext_wait_queue *receiver) 922{ 923 receiver->msg = message; 924 list_del(&receiver->list); 925 receiver->state = STATE_PENDING; 926 wake_up_process(receiver->task); 927 smp_wmb(); 928 receiver->state = STATE_READY; 929} 930 931/* pipelined_receive() - if there is task waiting in sys_mq_timedsend() 932 * gets its message and put to the queue (we have one free place for sure). */ 933static inline void pipelined_receive(struct mqueue_inode_info *info) 934{ 935 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND); 936 937 if (!sender) { 938 /* for poll */ 939 wake_up_interruptible(&info->wait_q); 940 return; 941 } 942 if (msg_insert(sender->msg, info)) 943 return; 944 list_del(&sender->list); 945 sender->state = STATE_PENDING; 946 wake_up_process(sender->task); 947 smp_wmb(); 948 sender->state = STATE_READY; 949} 950 951SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr, 952 size_t, msg_len, unsigned int, msg_prio, 953 const struct timespec __user *, u_abs_timeout) 954{ 955 struct fd f; 956 struct inode *inode; 957 struct ext_wait_queue wait; 958 struct ext_wait_queue *receiver; 959 struct msg_msg *msg_ptr; 960 struct mqueue_inode_info *info; 961 ktime_t expires, *timeout = NULL; 962 struct timespec ts; 963 struct posix_msg_tree_node *new_leaf = NULL; 964 int ret = 0; 965 966 if (u_abs_timeout) { 967 int res = prepare_timeout(u_abs_timeout, &expires, &ts); 968 if (res) 969 return res; 970 timeout = &expires; 971 } 972 973 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX)) 974 return -EINVAL; 975 976 audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL); 977 978 f = fdget(mqdes); 979 if (unlikely(!f.file)) { 980 ret = -EBADF; 981 goto out; 982 } 983 984 inode = file_inode(f.file); 985 if (unlikely(f.file->f_op != &mqueue_file_operations)) { 986 ret = -EBADF; 987 goto out_fput; 988 } 989 info = MQUEUE_I(inode); 990 audit_file(f.file); 991 992 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) { 993 ret = -EBADF; 994 goto out_fput; 995 } 996 997 if (unlikely(msg_len > info->attr.mq_msgsize)) { 998 ret = -EMSGSIZE; 999 goto out_fput; 1000 } 1001 1002 /* First try to allocate memory, before doing anything with 1003 * existing queues. */ 1004 msg_ptr = load_msg(u_msg_ptr, msg_len); 1005 if (IS_ERR(msg_ptr)) { 1006 ret = PTR_ERR(msg_ptr); 1007 goto out_fput; 1008 } 1009 msg_ptr->m_ts = msg_len; 1010 msg_ptr->m_type = msg_prio; 1011 1012 /* 1013 * msg_insert really wants us to have a valid, spare node struct so 1014 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will 1015 * fall back to that if necessary. 1016 */ 1017 if (!info->node_cache) 1018 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL); 1019 1020 spin_lock(&info->lock); 1021 1022 if (!info->node_cache && new_leaf) { 1023 /* Save our speculative allocation into the cache */ 1024 INIT_LIST_HEAD(&new_leaf->msg_list); 1025 info->node_cache = new_leaf; 1026 new_leaf = NULL; 1027 } else { 1028 kfree(new_leaf); 1029 } 1030 1031 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) { 1032 if (f.file->f_flags & O_NONBLOCK) { 1033 ret = -EAGAIN; 1034 } else { 1035 wait.task = current; 1036 wait.msg = (void *) msg_ptr; 1037 wait.state = STATE_NONE; 1038 ret = wq_sleep(info, SEND, timeout, &wait); 1039 /* 1040 * wq_sleep must be called with info->lock held, and 1041 * returns with the lock released 1042 */ 1043 goto out_free; 1044 } 1045 } else { 1046 receiver = wq_get_first_waiter(info, RECV); 1047 if (receiver) { 1048 pipelined_send(info, msg_ptr, receiver); 1049 } else { 1050 /* adds message to the queue */ 1051 ret = msg_insert(msg_ptr, info); 1052 if (ret) 1053 goto out_unlock; 1054 __do_notify(info); 1055 } 1056 inode->i_atime = inode->i_mtime = inode->i_ctime = 1057 CURRENT_TIME; 1058 } 1059out_unlock: 1060 spin_unlock(&info->lock); 1061out_free: 1062 if (ret) 1063 free_msg(msg_ptr); 1064out_fput: 1065 fdput(f); 1066out: 1067 return ret; 1068} 1069 1070SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr, 1071 size_t, msg_len, unsigned int __user *, u_msg_prio, 1072 const struct timespec __user *, u_abs_timeout) 1073{ 1074 ssize_t ret; 1075 struct msg_msg *msg_ptr; 1076 struct fd f; 1077 struct inode *inode; 1078 struct mqueue_inode_info *info; 1079 struct ext_wait_queue wait; 1080 ktime_t expires, *timeout = NULL; 1081 struct timespec ts; 1082 struct posix_msg_tree_node *new_leaf = NULL; 1083 1084 if (u_abs_timeout) { 1085 int res = prepare_timeout(u_abs_timeout, &expires, &ts); 1086 if (res) 1087 return res; 1088 timeout = &expires; 1089 } 1090 1091 audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL); 1092 1093 f = fdget(mqdes); 1094 if (unlikely(!f.file)) { 1095 ret = -EBADF; 1096 goto out; 1097 } 1098 1099 inode = file_inode(f.file); 1100 if (unlikely(f.file->f_op != &mqueue_file_operations)) { 1101 ret = -EBADF; 1102 goto out_fput; 1103 } 1104 info = MQUEUE_I(inode); 1105 audit_file(f.file); 1106 1107 if (unlikely(!(f.file->f_mode & FMODE_READ))) { 1108 ret = -EBADF; 1109 goto out_fput; 1110 } 1111 1112 /* checks if buffer is big enough */ 1113 if (unlikely(msg_len < info->attr.mq_msgsize)) { 1114 ret = -EMSGSIZE; 1115 goto out_fput; 1116 } 1117 1118 /* 1119 * msg_insert really wants us to have a valid, spare node struct so 1120 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will 1121 * fall back to that if necessary. 1122 */ 1123 if (!info->node_cache) 1124 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL); 1125 1126 spin_lock(&info->lock); 1127 1128 if (!info->node_cache && new_leaf) { 1129 /* Save our speculative allocation into the cache */ 1130 INIT_LIST_HEAD(&new_leaf->msg_list); 1131 info->node_cache = new_leaf; 1132 } else { 1133 kfree(new_leaf); 1134 } 1135 1136 if (info->attr.mq_curmsgs == 0) { 1137 if (f.file->f_flags & O_NONBLOCK) { 1138 spin_unlock(&info->lock); 1139 ret = -EAGAIN; 1140 } else { 1141 wait.task = current; 1142 wait.state = STATE_NONE; 1143 ret = wq_sleep(info, RECV, timeout, &wait); 1144 msg_ptr = wait.msg; 1145 } 1146 } else { 1147 msg_ptr = msg_get(info); 1148 1149 inode->i_atime = inode->i_mtime = inode->i_ctime = 1150 CURRENT_TIME; 1151 1152 /* There is now free space in queue. */ 1153 pipelined_receive(info); 1154 spin_unlock(&info->lock); 1155 ret = 0; 1156 } 1157 if (ret == 0) { 1158 ret = msg_ptr->m_ts; 1159 1160 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) || 1161 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) { 1162 ret = -EFAULT; 1163 } 1164 free_msg(msg_ptr); 1165 } 1166out_fput: 1167 fdput(f); 1168out: 1169 return ret; 1170} 1171 1172/* 1173 * Notes: the case when user wants us to deregister (with NULL as pointer) 1174 * and he isn't currently owner of notification, will be silently discarded. 1175 * It isn't explicitly defined in the POSIX. 1176 */ 1177SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes, 1178 const struct sigevent __user *, u_notification) 1179{ 1180 int ret; 1181 struct fd f; 1182 struct sock *sock; 1183 struct inode *inode; 1184 struct sigevent notification; 1185 struct mqueue_inode_info *info; 1186 struct sk_buff *nc; 1187 1188 if (u_notification) { 1189 if (copy_from_user(¬ification, u_notification, 1190 sizeof(struct sigevent))) 1191 return -EFAULT; 1192 } 1193 1194 audit_mq_notify(mqdes, u_notification ? ¬ification : NULL); 1195 1196 nc = NULL; 1197 sock = NULL; 1198 if (u_notification != NULL) { 1199 if (unlikely(notification.sigev_notify != SIGEV_NONE && 1200 notification.sigev_notify != SIGEV_SIGNAL && 1201 notification.sigev_notify != SIGEV_THREAD)) 1202 return -EINVAL; 1203 if (notification.sigev_notify == SIGEV_SIGNAL && 1204 !valid_signal(notification.sigev_signo)) { 1205 return -EINVAL; 1206 } 1207 if (notification.sigev_notify == SIGEV_THREAD) { 1208 long timeo; 1209 1210 /* create the notify skb */ 1211 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL); 1212 if (!nc) { 1213 ret = -ENOMEM; 1214 goto out; 1215 } 1216 if (copy_from_user(nc->data, 1217 notification.sigev_value.sival_ptr, 1218 NOTIFY_COOKIE_LEN)) { 1219 ret = -EFAULT; 1220 goto out; 1221 } 1222 1223 /* TODO: add a header? */ 1224 skb_put(nc, NOTIFY_COOKIE_LEN); 1225 /* and attach it to the socket */ 1226retry: 1227 f = fdget(notification.sigev_signo); 1228 if (!f.file) { 1229 ret = -EBADF; 1230 goto out; 1231 } 1232 sock = netlink_getsockbyfilp(f.file); 1233 fdput(f); 1234 if (IS_ERR(sock)) { 1235 ret = PTR_ERR(sock); 1236 sock = NULL; 1237 goto out; 1238 } 1239 1240 timeo = MAX_SCHEDULE_TIMEOUT; 1241 ret = netlink_attachskb(sock, nc, &timeo, NULL); 1242 if (ret == 1) 1243 goto retry; 1244 if (ret) { 1245 sock = NULL; 1246 nc = NULL; 1247 goto out; 1248 } 1249 } 1250 } 1251 1252 f = fdget(mqdes); 1253 if (!f.file) { 1254 ret = -EBADF; 1255 goto out; 1256 } 1257 1258 inode = file_inode(f.file); 1259 if (unlikely(f.file->f_op != &mqueue_file_operations)) { 1260 ret = -EBADF; 1261 goto out_fput; 1262 } 1263 info = MQUEUE_I(inode); 1264 1265 ret = 0; 1266 spin_lock(&info->lock); 1267 if (u_notification == NULL) { 1268 if (info->notify_owner == task_tgid(current)) { 1269 remove_notification(info); 1270 inode->i_atime = inode->i_ctime = CURRENT_TIME; 1271 } 1272 } else if (info->notify_owner != NULL) { 1273 ret = -EBUSY; 1274 } else { 1275 switch (notification.sigev_notify) { 1276 case SIGEV_NONE: 1277 info->notify.sigev_notify = SIGEV_NONE; 1278 break; 1279 case SIGEV_THREAD: 1280 info->notify_sock = sock; 1281 info->notify_cookie = nc; 1282 sock = NULL; 1283 nc = NULL; 1284 info->notify.sigev_notify = SIGEV_THREAD; 1285 break; 1286 case SIGEV_SIGNAL: 1287 info->notify.sigev_signo = notification.sigev_signo; 1288 info->notify.sigev_value = notification.sigev_value; 1289 info->notify.sigev_notify = SIGEV_SIGNAL; 1290 break; 1291 } 1292 1293 info->notify_owner = get_pid(task_tgid(current)); 1294 info->notify_user_ns = get_user_ns(current_user_ns()); 1295 inode->i_atime = inode->i_ctime = CURRENT_TIME; 1296 } 1297 spin_unlock(&info->lock); 1298out_fput: 1299 fdput(f); 1300out: 1301 if (sock) 1302 netlink_detachskb(sock, nc); 1303 else if (nc) 1304 dev_kfree_skb(nc); 1305 1306 return ret; 1307} 1308 1309SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes, 1310 const struct mq_attr __user *, u_mqstat, 1311 struct mq_attr __user *, u_omqstat) 1312{ 1313 int ret; 1314 struct mq_attr mqstat, omqstat; 1315 struct fd f; 1316 struct inode *inode; 1317 struct mqueue_inode_info *info; 1318 1319 if (u_mqstat != NULL) { 1320 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr))) 1321 return -EFAULT; 1322 if (mqstat.mq_flags & (~O_NONBLOCK)) 1323 return -EINVAL; 1324 } 1325 1326 f = fdget(mqdes); 1327 if (!f.file) { 1328 ret = -EBADF; 1329 goto out; 1330 } 1331 1332 inode = file_inode(f.file); 1333 if (unlikely(f.file->f_op != &mqueue_file_operations)) { 1334 ret = -EBADF; 1335 goto out_fput; 1336 } 1337 info = MQUEUE_I(inode); 1338 1339 spin_lock(&info->lock); 1340 1341 omqstat = info->attr; 1342 omqstat.mq_flags = f.file->f_flags & O_NONBLOCK; 1343 if (u_mqstat) { 1344 audit_mq_getsetattr(mqdes, &mqstat); 1345 spin_lock(&f.file->f_lock); 1346 if (mqstat.mq_flags & O_NONBLOCK) 1347 f.file->f_flags |= O_NONBLOCK; 1348 else 1349 f.file->f_flags &= ~O_NONBLOCK; 1350 spin_unlock(&f.file->f_lock); 1351 1352 inode->i_atime = inode->i_ctime = CURRENT_TIME; 1353 } 1354 1355 spin_unlock(&info->lock); 1356 1357 ret = 0; 1358 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat, 1359 sizeof(struct mq_attr))) 1360 ret = -EFAULT; 1361 1362out_fput: 1363 fdput(f); 1364out: 1365 return ret; 1366} 1367 1368static const struct inode_operations mqueue_dir_inode_operations = { 1369 .lookup = simple_lookup, 1370 .create = mqueue_create, 1371 .unlink = mqueue_unlink, 1372}; 1373 1374static const struct file_operations mqueue_file_operations = { 1375 .flush = mqueue_flush_file, 1376 .poll = mqueue_poll_file, 1377 .read = mqueue_read_file, 1378 .llseek = default_llseek, 1379}; 1380 1381static const struct super_operations mqueue_super_ops = { 1382 .alloc_inode = mqueue_alloc_inode, 1383 .destroy_inode = mqueue_destroy_inode, 1384 .evict_inode = mqueue_evict_inode, 1385 .statfs = simple_statfs, 1386}; 1387 1388static struct file_system_type mqueue_fs_type = { 1389 .name = "mqueue", 1390 .mount = mqueue_mount, 1391 .kill_sb = kill_litter_super, 1392 .fs_flags = FS_USERNS_MOUNT, 1393}; 1394 1395int mq_init_ns(struct ipc_namespace *ns) 1396{ 1397 ns->mq_queues_count = 0; 1398 ns->mq_queues_max = DFLT_QUEUESMAX; 1399 ns->mq_msg_max = DFLT_MSGMAX; 1400 ns->mq_msgsize_max = DFLT_MSGSIZEMAX; 1401 ns->mq_msg_default = DFLT_MSG; 1402 ns->mq_msgsize_default = DFLT_MSGSIZE; 1403 1404 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns); 1405 if (IS_ERR(ns->mq_mnt)) { 1406 int err = PTR_ERR(ns->mq_mnt); 1407 ns->mq_mnt = NULL; 1408 return err; 1409 } 1410 return 0; 1411} 1412 1413void mq_clear_sbinfo(struct ipc_namespace *ns) 1414{ 1415 ns->mq_mnt->mnt_sb->s_fs_info = NULL; 1416} 1417 1418void mq_put_mnt(struct ipc_namespace *ns) 1419{ 1420 kern_unmount(ns->mq_mnt); 1421} 1422 1423static int __init init_mqueue_fs(void) 1424{ 1425 int error; 1426 1427 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache", 1428 sizeof(struct mqueue_inode_info), 0, 1429 SLAB_HWCACHE_ALIGN, init_once); 1430 if (mqueue_inode_cachep == NULL) 1431 return -ENOMEM; 1432 1433 /* ignore failures - they are not fatal */ 1434 mq_sysctl_table = mq_register_sysctl_table(); 1435 1436 error = register_filesystem(&mqueue_fs_type); 1437 if (error) 1438 goto out_sysctl; 1439 1440 spin_lock_init(&mq_lock); 1441 1442 error = mq_init_ns(&init_ipc_ns); 1443 if (error) 1444 goto out_filesystem; 1445 1446 return 0; 1447 1448out_filesystem: 1449 unregister_filesystem(&mqueue_fs_type); 1450out_sysctl: 1451 if (mq_sysctl_table) 1452 unregister_sysctl_table(mq_sysctl_table); 1453 kmem_cache_destroy(mqueue_inode_cachep); 1454 return error; 1455} 1456 1457device_initcall(init_mqueue_fs); 1458