1 /* 2 * POSIX message queues filesystem for Linux. 3 * 4 * Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl) 5 * Michal Wronski (michal.wronski@gmail.com) 6 * 7 * Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com) 8 * Lockless receive & send, fd based notify: 9 * Manfred Spraul (manfred@colorfullife.com) 10 * 11 * Audit: George Wilson (ltcgcw@us.ibm.com) 12 * 13 * This file is released under the GPL. 14 */ 15 16 #include <linux/capability.h> 17 #include <linux/init.h> 18 #include <linux/pagemap.h> 19 #include <linux/file.h> 20 #include <linux/mount.h> 21 #include <linux/namei.h> 22 #include <linux/sysctl.h> 23 #include <linux/poll.h> 24 #include <linux/mqueue.h> 25 #include <linux/msg.h> 26 #include <linux/skbuff.h> 27 #include <linux/vmalloc.h> 28 #include <linux/netlink.h> 29 #include <linux/syscalls.h> 30 #include <linux/audit.h> 31 #include <linux/signal.h> 32 #include <linux/mutex.h> 33 #include <linux/nsproxy.h> 34 #include <linux/pid.h> 35 #include <linux/ipc_namespace.h> 36 #include <linux/user_namespace.h> 37 #include <linux/slab.h> 38 39 #include <net/sock.h> 40 #include "util.h" 41 42 #define MQUEUE_MAGIC 0x19800202 43 #define DIRENT_SIZE 20 44 #define FILENT_SIZE 80 45 46 #define SEND 0 47 #define RECV 1 48 49 #define STATE_NONE 0 50 #define STATE_PENDING 1 51 #define STATE_READY 2 52 53 struct posix_msg_tree_node { 54 struct rb_node rb_node; 55 struct list_head msg_list; 56 int priority; 57 }; 58 59 struct ext_wait_queue { /* queue of sleeping tasks */ 60 struct task_struct *task; 61 struct list_head list; 62 struct msg_msg *msg; /* ptr of loaded message */ 63 int state; /* one of STATE_* values */ 64 }; 65 66 struct mqueue_inode_info { 67 spinlock_t lock; 68 struct inode vfs_inode; 69 wait_queue_head_t wait_q; 70 71 struct rb_root msg_tree; 72 struct posix_msg_tree_node *node_cache; 73 struct mq_attr attr; 74 75 struct sigevent notify; 76 struct pid* notify_owner; 77 struct user_namespace *notify_user_ns; 78 struct user_struct *user; /* user who created, for accounting */ 79 struct sock *notify_sock; 80 struct sk_buff *notify_cookie; 81 82 /* for tasks waiting for free space and messages, respectively */ 83 struct ext_wait_queue e_wait_q[2]; 84 85 unsigned long qsize; /* size of queue in memory (sum of all msgs) */ 86 }; 87 88 static const struct inode_operations mqueue_dir_inode_operations; 89 static const struct file_operations mqueue_file_operations; 90 static const struct super_operations mqueue_super_ops; 91 static void remove_notification(struct mqueue_inode_info *info); 92 93 static struct kmem_cache *mqueue_inode_cachep; 94 95 static struct ctl_table_header * mq_sysctl_table; 96 97 static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode) 98 { 99 return container_of(inode, struct mqueue_inode_info, vfs_inode); 100 } 101 102 /* 103 * This routine should be called with the mq_lock held. 104 */ 105 static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode) 106 { 107 return get_ipc_ns(inode->i_sb->s_fs_info); 108 } 109 110 static struct ipc_namespace *get_ns_from_inode(struct inode *inode) 111 { 112 struct ipc_namespace *ns; 113 114 spin_lock(&mq_lock); 115 ns = __get_ns_from_inode(inode); 116 spin_unlock(&mq_lock); 117 return ns; 118 } 119 120 /* Auxiliary functions to manipulate messages' list */ 121 static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info) 122 { 123 struct rb_node **p, *parent = NULL; 124 struct posix_msg_tree_node *leaf; 125 126 p = &info->msg_tree.rb_node; 127 while (*p) { 128 parent = *p; 129 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node); 130 131 if (likely(leaf->priority == msg->m_type)) 132 goto insert_msg; 133 else if (msg->m_type < leaf->priority) 134 p = &(*p)->rb_left; 135 else 136 p = &(*p)->rb_right; 137 } 138 if (info->node_cache) { 139 leaf = info->node_cache; 140 info->node_cache = NULL; 141 } else { 142 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC); 143 if (!leaf) 144 return -ENOMEM; 145 INIT_LIST_HEAD(&leaf->msg_list); 146 info->qsize += sizeof(*leaf); 147 } 148 leaf->priority = msg->m_type; 149 rb_link_node(&leaf->rb_node, parent, p); 150 rb_insert_color(&leaf->rb_node, &info->msg_tree); 151 insert_msg: 152 info->attr.mq_curmsgs++; 153 info->qsize += msg->m_ts; 154 list_add_tail(&msg->m_list, &leaf->msg_list); 155 return 0; 156 } 157 158 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info) 159 { 160 struct rb_node **p, *parent = NULL; 161 struct posix_msg_tree_node *leaf; 162 struct msg_msg *msg; 163 164 try_again: 165 p = &info->msg_tree.rb_node; 166 while (*p) { 167 parent = *p; 168 /* 169 * During insert, low priorities go to the left and high to the 170 * right. On receive, we want the highest priorities first, so 171 * walk all the way to the right. 172 */ 173 p = &(*p)->rb_right; 174 } 175 if (!parent) { 176 if (info->attr.mq_curmsgs) { 177 pr_warn_once("Inconsistency in POSIX message queue, " 178 "no tree element, but supposedly messages " 179 "should exist!\n"); 180 info->attr.mq_curmsgs = 0; 181 } 182 return NULL; 183 } 184 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node); 185 if (unlikely(list_empty(&leaf->msg_list))) { 186 pr_warn_once("Inconsistency in POSIX message queue, " 187 "empty leaf node but we haven't implemented " 188 "lazy leaf delete!\n"); 189 rb_erase(&leaf->rb_node, &info->msg_tree); 190 if (info->node_cache) { 191 info->qsize -= sizeof(*leaf); 192 kfree(leaf); 193 } else { 194 info->node_cache = leaf; 195 } 196 goto try_again; 197 } else { 198 msg = list_first_entry(&leaf->msg_list, 199 struct msg_msg, m_list); 200 list_del(&msg->m_list); 201 if (list_empty(&leaf->msg_list)) { 202 rb_erase(&leaf->rb_node, &info->msg_tree); 203 if (info->node_cache) { 204 info->qsize -= sizeof(*leaf); 205 kfree(leaf); 206 } else { 207 info->node_cache = leaf; 208 } 209 } 210 } 211 info->attr.mq_curmsgs--; 212 info->qsize -= msg->m_ts; 213 return msg; 214 } 215 216 static struct inode *mqueue_get_inode(struct super_block *sb, 217 struct ipc_namespace *ipc_ns, umode_t mode, 218 struct mq_attr *attr) 219 { 220 struct user_struct *u = current_user(); 221 struct inode *inode; 222 int ret = -ENOMEM; 223 224 inode = new_inode(sb); 225 if (!inode) 226 goto err; 227 228 inode->i_ino = get_next_ino(); 229 inode->i_mode = mode; 230 inode->i_uid = current_fsuid(); 231 inode->i_gid = current_fsgid(); 232 inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME; 233 234 if (S_ISREG(mode)) { 235 struct mqueue_inode_info *info; 236 unsigned long mq_bytes, mq_treesize; 237 238 inode->i_fop = &mqueue_file_operations; 239 inode->i_size = FILENT_SIZE; 240 /* mqueue specific info */ 241 info = MQUEUE_I(inode); 242 spin_lock_init(&info->lock); 243 init_waitqueue_head(&info->wait_q); 244 INIT_LIST_HEAD(&info->e_wait_q[0].list); 245 INIT_LIST_HEAD(&info->e_wait_q[1].list); 246 info->notify_owner = NULL; 247 info->notify_user_ns = NULL; 248 info->qsize = 0; 249 info->user = NULL; /* set when all is ok */ 250 info->msg_tree = RB_ROOT; 251 info->node_cache = NULL; 252 memset(&info->attr, 0, sizeof(info->attr)); 253 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max, 254 ipc_ns->mq_msg_default); 255 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max, 256 ipc_ns->mq_msgsize_default); 257 if (attr) { 258 info->attr.mq_maxmsg = attr->mq_maxmsg; 259 info->attr.mq_msgsize = attr->mq_msgsize; 260 } 261 /* 262 * We used to allocate a static array of pointers and account 263 * the size of that array as well as one msg_msg struct per 264 * possible message into the queue size. That's no longer 265 * accurate as the queue is now an rbtree and will grow and 266 * shrink depending on usage patterns. We can, however, still 267 * account one msg_msg struct per message, but the nodes are 268 * allocated depending on priority usage, and most programs 269 * only use one, or a handful, of priorities. However, since 270 * this is pinned memory, we need to assume worst case, so 271 * that means the min(mq_maxmsg, max_priorities) * struct 272 * posix_msg_tree_node. 273 */ 274 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) + 275 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) * 276 sizeof(struct posix_msg_tree_node); 277 278 mq_bytes = mq_treesize + (info->attr.mq_maxmsg * 279 info->attr.mq_msgsize); 280 281 spin_lock(&mq_lock); 282 if (u->mq_bytes + mq_bytes < u->mq_bytes || 283 u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) { 284 spin_unlock(&mq_lock); 285 /* mqueue_evict_inode() releases info->messages */ 286 ret = -EMFILE; 287 goto out_inode; 288 } 289 u->mq_bytes += mq_bytes; 290 spin_unlock(&mq_lock); 291 292 /* all is ok */ 293 info->user = get_uid(u); 294 } else if (S_ISDIR(mode)) { 295 inc_nlink(inode); 296 /* Some things misbehave if size == 0 on a directory */ 297 inode->i_size = 2 * DIRENT_SIZE; 298 inode->i_op = &mqueue_dir_inode_operations; 299 inode->i_fop = &simple_dir_operations; 300 } 301 302 return inode; 303 out_inode: 304 iput(inode); 305 err: 306 return ERR_PTR(ret); 307 } 308 309 static int mqueue_fill_super(struct super_block *sb, void *data, int silent) 310 { 311 struct inode *inode; 312 struct ipc_namespace *ns = data; 313 314 sb->s_blocksize = PAGE_CACHE_SIZE; 315 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 316 sb->s_magic = MQUEUE_MAGIC; 317 sb->s_op = &mqueue_super_ops; 318 319 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL); 320 if (IS_ERR(inode)) 321 return PTR_ERR(inode); 322 323 sb->s_root = d_make_root(inode); 324 if (!sb->s_root) 325 return -ENOMEM; 326 return 0; 327 } 328 329 static struct dentry *mqueue_mount(struct file_system_type *fs_type, 330 int flags, const char *dev_name, 331 void *data) 332 { 333 if (!(flags & MS_KERNMOUNT)) { 334 struct ipc_namespace *ns = current->nsproxy->ipc_ns; 335 /* Don't allow mounting unless the caller has CAP_SYS_ADMIN 336 * over the ipc namespace. 337 */ 338 if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN)) 339 return ERR_PTR(-EPERM); 340 341 data = ns; 342 } 343 return mount_ns(fs_type, flags, data, mqueue_fill_super); 344 } 345 346 static void init_once(void *foo) 347 { 348 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo; 349 350 inode_init_once(&p->vfs_inode); 351 } 352 353 static struct inode *mqueue_alloc_inode(struct super_block *sb) 354 { 355 struct mqueue_inode_info *ei; 356 357 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL); 358 if (!ei) 359 return NULL; 360 return &ei->vfs_inode; 361 } 362 363 static void mqueue_i_callback(struct rcu_head *head) 364 { 365 struct inode *inode = container_of(head, struct inode, i_rcu); 366 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode)); 367 } 368 369 static void mqueue_destroy_inode(struct inode *inode) 370 { 371 call_rcu(&inode->i_rcu, mqueue_i_callback); 372 } 373 374 static void mqueue_evict_inode(struct inode *inode) 375 { 376 struct mqueue_inode_info *info; 377 struct user_struct *user; 378 unsigned long mq_bytes, mq_treesize; 379 struct ipc_namespace *ipc_ns; 380 struct msg_msg *msg; 381 382 clear_inode(inode); 383 384 if (S_ISDIR(inode->i_mode)) 385 return; 386 387 ipc_ns = get_ns_from_inode(inode); 388 info = MQUEUE_I(inode); 389 spin_lock(&info->lock); 390 while ((msg = msg_get(info)) != NULL) 391 free_msg(msg); 392 kfree(info->node_cache); 393 spin_unlock(&info->lock); 394 395 /* Total amount of bytes accounted for the mqueue */ 396 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) + 397 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) * 398 sizeof(struct posix_msg_tree_node); 399 400 mq_bytes = mq_treesize + (info->attr.mq_maxmsg * 401 info->attr.mq_msgsize); 402 403 user = info->user; 404 if (user) { 405 spin_lock(&mq_lock); 406 user->mq_bytes -= mq_bytes; 407 /* 408 * get_ns_from_inode() ensures that the 409 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns 410 * to which we now hold a reference, or it is NULL. 411 * We can't put it here under mq_lock, though. 412 */ 413 if (ipc_ns) 414 ipc_ns->mq_queues_count--; 415 spin_unlock(&mq_lock); 416 free_uid(user); 417 } 418 if (ipc_ns) 419 put_ipc_ns(ipc_ns); 420 } 421 422 static int mqueue_create(struct inode *dir, struct dentry *dentry, 423 umode_t mode, bool excl) 424 { 425 struct inode *inode; 426 struct mq_attr *attr = dentry->d_fsdata; 427 int error; 428 struct ipc_namespace *ipc_ns; 429 430 spin_lock(&mq_lock); 431 ipc_ns = __get_ns_from_inode(dir); 432 if (!ipc_ns) { 433 error = -EACCES; 434 goto out_unlock; 435 } 436 if (ipc_ns->mq_queues_count >= HARD_QUEUESMAX || 437 (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max && 438 !capable(CAP_SYS_RESOURCE))) { 439 error = -ENOSPC; 440 goto out_unlock; 441 } 442 ipc_ns->mq_queues_count++; 443 spin_unlock(&mq_lock); 444 445 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr); 446 if (IS_ERR(inode)) { 447 error = PTR_ERR(inode); 448 spin_lock(&mq_lock); 449 ipc_ns->mq_queues_count--; 450 goto out_unlock; 451 } 452 453 put_ipc_ns(ipc_ns); 454 dir->i_size += DIRENT_SIZE; 455 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME; 456 457 d_instantiate(dentry, inode); 458 dget(dentry); 459 return 0; 460 out_unlock: 461 spin_unlock(&mq_lock); 462 if (ipc_ns) 463 put_ipc_ns(ipc_ns); 464 return error; 465 } 466 467 static int mqueue_unlink(struct inode *dir, struct dentry *dentry) 468 { 469 struct inode *inode = dentry->d_inode; 470 471 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME; 472 dir->i_size -= DIRENT_SIZE; 473 drop_nlink(inode); 474 dput(dentry); 475 return 0; 476 } 477 478 /* 479 * This is routine for system read from queue file. 480 * To avoid mess with doing here some sort of mq_receive we allow 481 * to read only queue size & notification info (the only values 482 * that are interesting from user point of view and aren't accessible 483 * through std routines) 484 */ 485 static ssize_t mqueue_read_file(struct file *filp, char __user *u_data, 486 size_t count, loff_t *off) 487 { 488 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp)); 489 char buffer[FILENT_SIZE]; 490 ssize_t ret; 491 492 spin_lock(&info->lock); 493 snprintf(buffer, sizeof(buffer), 494 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n", 495 info->qsize, 496 info->notify_owner ? info->notify.sigev_notify : 0, 497 (info->notify_owner && 498 info->notify.sigev_notify == SIGEV_SIGNAL) ? 499 info->notify.sigev_signo : 0, 500 pid_vnr(info->notify_owner)); 501 spin_unlock(&info->lock); 502 buffer[sizeof(buffer)-1] = '\0'; 503 504 ret = simple_read_from_buffer(u_data, count, off, buffer, 505 strlen(buffer)); 506 if (ret <= 0) 507 return ret; 508 509 file_inode(filp)->i_atime = file_inode(filp)->i_ctime = CURRENT_TIME; 510 return ret; 511 } 512 513 static int mqueue_flush_file(struct file *filp, fl_owner_t id) 514 { 515 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp)); 516 517 spin_lock(&info->lock); 518 if (task_tgid(current) == info->notify_owner) 519 remove_notification(info); 520 521 spin_unlock(&info->lock); 522 return 0; 523 } 524 525 static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab) 526 { 527 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp)); 528 int retval = 0; 529 530 poll_wait(filp, &info->wait_q, poll_tab); 531 532 spin_lock(&info->lock); 533 if (info->attr.mq_curmsgs) 534 retval = POLLIN | POLLRDNORM; 535 536 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg) 537 retval |= POLLOUT | POLLWRNORM; 538 spin_unlock(&info->lock); 539 540 return retval; 541 } 542 543 /* Adds current to info->e_wait_q[sr] before element with smaller prio */ 544 static void wq_add(struct mqueue_inode_info *info, int sr, 545 struct ext_wait_queue *ewp) 546 { 547 struct ext_wait_queue *walk; 548 549 ewp->task = current; 550 551 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) { 552 if (walk->task->static_prio <= current->static_prio) { 553 list_add_tail(&ewp->list, &walk->list); 554 return; 555 } 556 } 557 list_add_tail(&ewp->list, &info->e_wait_q[sr].list); 558 } 559 560 /* 561 * Puts current task to sleep. Caller must hold queue lock. After return 562 * lock isn't held. 563 * sr: SEND or RECV 564 */ 565 static int wq_sleep(struct mqueue_inode_info *info, int sr, 566 ktime_t *timeout, struct ext_wait_queue *ewp) 567 { 568 int retval; 569 signed long time; 570 571 wq_add(info, sr, ewp); 572 573 for (;;) { 574 set_current_state(TASK_INTERRUPTIBLE); 575 576 spin_unlock(&info->lock); 577 time = schedule_hrtimeout_range_clock(timeout, 0, 578 HRTIMER_MODE_ABS, CLOCK_REALTIME); 579 580 while (ewp->state == STATE_PENDING) 581 cpu_relax(); 582 583 if (ewp->state == STATE_READY) { 584 retval = 0; 585 goto out; 586 } 587 spin_lock(&info->lock); 588 if (ewp->state == STATE_READY) { 589 retval = 0; 590 goto out_unlock; 591 } 592 if (signal_pending(current)) { 593 retval = -ERESTARTSYS; 594 break; 595 } 596 if (time == 0) { 597 retval = -ETIMEDOUT; 598 break; 599 } 600 } 601 list_del(&ewp->list); 602 out_unlock: 603 spin_unlock(&info->lock); 604 out: 605 return retval; 606 } 607 608 /* 609 * Returns waiting task that should be serviced first or NULL if none exists 610 */ 611 static struct ext_wait_queue *wq_get_first_waiter( 612 struct mqueue_inode_info *info, int sr) 613 { 614 struct list_head *ptr; 615 616 ptr = info->e_wait_q[sr].list.prev; 617 if (ptr == &info->e_wait_q[sr].list) 618 return NULL; 619 return list_entry(ptr, struct ext_wait_queue, list); 620 } 621 622 623 static inline void set_cookie(struct sk_buff *skb, char code) 624 { 625 ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code; 626 } 627 628 /* 629 * The next function is only to split too long sys_mq_timedsend 630 */ 631 static void __do_notify(struct mqueue_inode_info *info) 632 { 633 /* notification 634 * invoked when there is registered process and there isn't process 635 * waiting synchronously for message AND state of queue changed from 636 * empty to not empty. Here we are sure that no one is waiting 637 * synchronously. */ 638 if (info->notify_owner && 639 info->attr.mq_curmsgs == 1) { 640 struct siginfo sig_i; 641 switch (info->notify.sigev_notify) { 642 case SIGEV_NONE: 643 break; 644 case SIGEV_SIGNAL: 645 /* sends signal */ 646 647 sig_i.si_signo = info->notify.sigev_signo; 648 sig_i.si_errno = 0; 649 sig_i.si_code = SI_MESGQ; 650 sig_i.si_value = info->notify.sigev_value; 651 /* map current pid/uid into info->owner's namespaces */ 652 rcu_read_lock(); 653 sig_i.si_pid = task_tgid_nr_ns(current, 654 ns_of_pid(info->notify_owner)); 655 sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid()); 656 rcu_read_unlock(); 657 658 kill_pid_info(info->notify.sigev_signo, 659 &sig_i, info->notify_owner); 660 break; 661 case SIGEV_THREAD: 662 set_cookie(info->notify_cookie, NOTIFY_WOKENUP); 663 netlink_sendskb(info->notify_sock, info->notify_cookie); 664 break; 665 } 666 /* after notification unregisters process */ 667 put_pid(info->notify_owner); 668 put_user_ns(info->notify_user_ns); 669 info->notify_owner = NULL; 670 info->notify_user_ns = NULL; 671 } 672 wake_up(&info->wait_q); 673 } 674 675 static int prepare_timeout(const struct timespec __user *u_abs_timeout, 676 ktime_t *expires, struct timespec *ts) 677 { 678 if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec))) 679 return -EFAULT; 680 if (!timespec_valid(ts)) 681 return -EINVAL; 682 683 *expires = timespec_to_ktime(*ts); 684 return 0; 685 } 686 687 static void remove_notification(struct mqueue_inode_info *info) 688 { 689 if (info->notify_owner != NULL && 690 info->notify.sigev_notify == SIGEV_THREAD) { 691 set_cookie(info->notify_cookie, NOTIFY_REMOVED); 692 netlink_sendskb(info->notify_sock, info->notify_cookie); 693 } 694 put_pid(info->notify_owner); 695 put_user_ns(info->notify_user_ns); 696 info->notify_owner = NULL; 697 info->notify_user_ns = NULL; 698 } 699 700 static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr) 701 { 702 int mq_treesize; 703 unsigned long total_size; 704 705 if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0) 706 return -EINVAL; 707 if (capable(CAP_SYS_RESOURCE)) { 708 if (attr->mq_maxmsg > HARD_MSGMAX || 709 attr->mq_msgsize > HARD_MSGSIZEMAX) 710 return -EINVAL; 711 } else { 712 if (attr->mq_maxmsg > ipc_ns->mq_msg_max || 713 attr->mq_msgsize > ipc_ns->mq_msgsize_max) 714 return -EINVAL; 715 } 716 /* check for overflow */ 717 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg) 718 return -EOVERFLOW; 719 mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) + 720 min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) * 721 sizeof(struct posix_msg_tree_node); 722 total_size = attr->mq_maxmsg * attr->mq_msgsize; 723 if (total_size + mq_treesize < total_size) 724 return -EOVERFLOW; 725 return 0; 726 } 727 728 /* 729 * Invoked when creating a new queue via sys_mq_open 730 */ 731 static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir, 732 struct path *path, int oflag, umode_t mode, 733 struct mq_attr *attr) 734 { 735 const struct cred *cred = current_cred(); 736 int ret; 737 738 if (attr) { 739 ret = mq_attr_ok(ipc_ns, attr); 740 if (ret) 741 return ERR_PTR(ret); 742 /* store for use during create */ 743 path->dentry->d_fsdata = attr; 744 } else { 745 struct mq_attr def_attr; 746 747 def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max, 748 ipc_ns->mq_msg_default); 749 def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max, 750 ipc_ns->mq_msgsize_default); 751 ret = mq_attr_ok(ipc_ns, &def_attr); 752 if (ret) 753 return ERR_PTR(ret); 754 } 755 756 mode &= ~current_umask(); 757 ret = vfs_create(dir, path->dentry, mode, true); 758 path->dentry->d_fsdata = NULL; 759 if (ret) 760 return ERR_PTR(ret); 761 return dentry_open(path, oflag, cred); 762 } 763 764 /* Opens existing queue */ 765 static struct file *do_open(struct path *path, int oflag) 766 { 767 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE, 768 MAY_READ | MAY_WRITE }; 769 int acc; 770 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) 771 return ERR_PTR(-EINVAL); 772 acc = oflag2acc[oflag & O_ACCMODE]; 773 if (inode_permission(path->dentry->d_inode, acc)) 774 return ERR_PTR(-EACCES); 775 return dentry_open(path, oflag, current_cred()); 776 } 777 778 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode, 779 struct mq_attr __user *, u_attr) 780 { 781 struct path path; 782 struct file *filp; 783 struct filename *name; 784 struct mq_attr attr; 785 int fd, error; 786 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; 787 struct vfsmount *mnt = ipc_ns->mq_mnt; 788 struct dentry *root = mnt->mnt_root; 789 int ro; 790 791 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr))) 792 return -EFAULT; 793 794 audit_mq_open(oflag, mode, u_attr ? &attr : NULL); 795 796 if (IS_ERR(name = getname(u_name))) 797 return PTR_ERR(name); 798 799 fd = get_unused_fd_flags(O_CLOEXEC); 800 if (fd < 0) 801 goto out_putname; 802 803 ro = mnt_want_write(mnt); /* we'll drop it in any case */ 804 error = 0; 805 mutex_lock(&root->d_inode->i_mutex); 806 path.dentry = lookup_one_len(name->name, root, strlen(name->name)); 807 if (IS_ERR(path.dentry)) { 808 error = PTR_ERR(path.dentry); 809 goto out_putfd; 810 } 811 path.mnt = mntget(mnt); 812 813 if (oflag & O_CREAT) { 814 if (path.dentry->d_inode) { /* entry already exists */ 815 audit_inode(name, path.dentry, 0); 816 if (oflag & O_EXCL) { 817 error = -EEXIST; 818 goto out; 819 } 820 filp = do_open(&path, oflag); 821 } else { 822 if (ro) { 823 error = ro; 824 goto out; 825 } 826 filp = do_create(ipc_ns, root->d_inode, 827 &path, oflag, mode, 828 u_attr ? &attr : NULL); 829 } 830 } else { 831 if (!path.dentry->d_inode) { 832 error = -ENOENT; 833 goto out; 834 } 835 audit_inode(name, path.dentry, 0); 836 filp = do_open(&path, oflag); 837 } 838 839 if (!IS_ERR(filp)) 840 fd_install(fd, filp); 841 else 842 error = PTR_ERR(filp); 843 out: 844 path_put(&path); 845 out_putfd: 846 if (error) { 847 put_unused_fd(fd); 848 fd = error; 849 } 850 mutex_unlock(&root->d_inode->i_mutex); 851 if (!ro) 852 mnt_drop_write(mnt); 853 out_putname: 854 putname(name); 855 return fd; 856 } 857 858 SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name) 859 { 860 int err; 861 struct filename *name; 862 struct dentry *dentry; 863 struct inode *inode = NULL; 864 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; 865 struct vfsmount *mnt = ipc_ns->mq_mnt; 866 867 name = getname(u_name); 868 if (IS_ERR(name)) 869 return PTR_ERR(name); 870 871 err = mnt_want_write(mnt); 872 if (err) 873 goto out_name; 874 mutex_lock_nested(&mnt->mnt_root->d_inode->i_mutex, I_MUTEX_PARENT); 875 dentry = lookup_one_len(name->name, mnt->mnt_root, 876 strlen(name->name)); 877 if (IS_ERR(dentry)) { 878 err = PTR_ERR(dentry); 879 goto out_unlock; 880 } 881 882 inode = dentry->d_inode; 883 if (!inode) { 884 err = -ENOENT; 885 } else { 886 ihold(inode); 887 err = vfs_unlink(dentry->d_parent->d_inode, dentry); 888 } 889 dput(dentry); 890 891 out_unlock: 892 mutex_unlock(&mnt->mnt_root->d_inode->i_mutex); 893 if (inode) 894 iput(inode); 895 mnt_drop_write(mnt); 896 out_name: 897 putname(name); 898 899 return err; 900 } 901 902 /* Pipelined send and receive functions. 903 * 904 * If a receiver finds no waiting message, then it registers itself in the 905 * list of waiting receivers. A sender checks that list before adding the new 906 * message into the message array. If there is a waiting receiver, then it 907 * bypasses the message array and directly hands the message over to the 908 * receiver. 909 * The receiver accepts the message and returns without grabbing the queue 910 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers 911 * are necessary. The same algorithm is used for sysv semaphores, see 912 * ipc/sem.c for more details. 913 * 914 * The same algorithm is used for senders. 915 */ 916 917 /* pipelined_send() - send a message directly to the task waiting in 918 * sys_mq_timedreceive() (without inserting message into a queue). 919 */ 920 static inline void pipelined_send(struct mqueue_inode_info *info, 921 struct msg_msg *message, 922 struct ext_wait_queue *receiver) 923 { 924 receiver->msg = message; 925 list_del(&receiver->list); 926 receiver->state = STATE_PENDING; 927 wake_up_process(receiver->task); 928 smp_wmb(); 929 receiver->state = STATE_READY; 930 } 931 932 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend() 933 * gets its message and put to the queue (we have one free place for sure). */ 934 static inline void pipelined_receive(struct mqueue_inode_info *info) 935 { 936 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND); 937 938 if (!sender) { 939 /* for poll */ 940 wake_up_interruptible(&info->wait_q); 941 return; 942 } 943 if (msg_insert(sender->msg, info)) 944 return; 945 list_del(&sender->list); 946 sender->state = STATE_PENDING; 947 wake_up_process(sender->task); 948 smp_wmb(); 949 sender->state = STATE_READY; 950 } 951 952 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr, 953 size_t, msg_len, unsigned int, msg_prio, 954 const struct timespec __user *, u_abs_timeout) 955 { 956 struct fd f; 957 struct inode *inode; 958 struct ext_wait_queue wait; 959 struct ext_wait_queue *receiver; 960 struct msg_msg *msg_ptr; 961 struct mqueue_inode_info *info; 962 ktime_t expires, *timeout = NULL; 963 struct timespec ts; 964 struct posix_msg_tree_node *new_leaf = NULL; 965 int ret = 0; 966 967 if (u_abs_timeout) { 968 int res = prepare_timeout(u_abs_timeout, &expires, &ts); 969 if (res) 970 return res; 971 timeout = &expires; 972 } 973 974 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX)) 975 return -EINVAL; 976 977 audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL); 978 979 f = fdget(mqdes); 980 if (unlikely(!f.file)) { 981 ret = -EBADF; 982 goto out; 983 } 984 985 inode = file_inode(f.file); 986 if (unlikely(f.file->f_op != &mqueue_file_operations)) { 987 ret = -EBADF; 988 goto out_fput; 989 } 990 info = MQUEUE_I(inode); 991 audit_inode(NULL, f.file->f_path.dentry, 0); 992 993 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) { 994 ret = -EBADF; 995 goto out_fput; 996 } 997 998 if (unlikely(msg_len > info->attr.mq_msgsize)) { 999 ret = -EMSGSIZE; 1000 goto out_fput; 1001 } 1002 1003 /* First try to allocate memory, before doing anything with 1004 * existing queues. */ 1005 msg_ptr = load_msg(u_msg_ptr, msg_len); 1006 if (IS_ERR(msg_ptr)) { 1007 ret = PTR_ERR(msg_ptr); 1008 goto out_fput; 1009 } 1010 msg_ptr->m_ts = msg_len; 1011 msg_ptr->m_type = msg_prio; 1012 1013 /* 1014 * msg_insert really wants us to have a valid, spare node struct so 1015 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will 1016 * fall back to that if necessary. 1017 */ 1018 if (!info->node_cache) 1019 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL); 1020 1021 spin_lock(&info->lock); 1022 1023 if (!info->node_cache && new_leaf) { 1024 /* Save our speculative allocation into the cache */ 1025 INIT_LIST_HEAD(&new_leaf->msg_list); 1026 info->node_cache = new_leaf; 1027 info->qsize += sizeof(*new_leaf); 1028 new_leaf = NULL; 1029 } else { 1030 kfree(new_leaf); 1031 } 1032 1033 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) { 1034 if (f.file->f_flags & O_NONBLOCK) { 1035 ret = -EAGAIN; 1036 } else { 1037 wait.task = current; 1038 wait.msg = (void *) msg_ptr; 1039 wait.state = STATE_NONE; 1040 ret = wq_sleep(info, SEND, timeout, &wait); 1041 /* 1042 * wq_sleep must be called with info->lock held, and 1043 * returns with the lock released 1044 */ 1045 goto out_free; 1046 } 1047 } else { 1048 receiver = wq_get_first_waiter(info, RECV); 1049 if (receiver) { 1050 pipelined_send(info, msg_ptr, receiver); 1051 } else { 1052 /* adds message to the queue */ 1053 ret = msg_insert(msg_ptr, info); 1054 if (ret) 1055 goto out_unlock; 1056 __do_notify(info); 1057 } 1058 inode->i_atime = inode->i_mtime = inode->i_ctime = 1059 CURRENT_TIME; 1060 } 1061 out_unlock: 1062 spin_unlock(&info->lock); 1063 out_free: 1064 if (ret) 1065 free_msg(msg_ptr); 1066 out_fput: 1067 fdput(f); 1068 out: 1069 return ret; 1070 } 1071 1072 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr, 1073 size_t, msg_len, unsigned int __user *, u_msg_prio, 1074 const struct timespec __user *, u_abs_timeout) 1075 { 1076 ssize_t ret; 1077 struct msg_msg *msg_ptr; 1078 struct fd f; 1079 struct inode *inode; 1080 struct mqueue_inode_info *info; 1081 struct ext_wait_queue wait; 1082 ktime_t expires, *timeout = NULL; 1083 struct timespec ts; 1084 struct posix_msg_tree_node *new_leaf = NULL; 1085 1086 if (u_abs_timeout) { 1087 int res = prepare_timeout(u_abs_timeout, &expires, &ts); 1088 if (res) 1089 return res; 1090 timeout = &expires; 1091 } 1092 1093 audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL); 1094 1095 f = fdget(mqdes); 1096 if (unlikely(!f.file)) { 1097 ret = -EBADF; 1098 goto out; 1099 } 1100 1101 inode = file_inode(f.file); 1102 if (unlikely(f.file->f_op != &mqueue_file_operations)) { 1103 ret = -EBADF; 1104 goto out_fput; 1105 } 1106 info = MQUEUE_I(inode); 1107 audit_inode(NULL, f.file->f_path.dentry, 0); 1108 1109 if (unlikely(!(f.file->f_mode & FMODE_READ))) { 1110 ret = -EBADF; 1111 goto out_fput; 1112 } 1113 1114 /* checks if buffer is big enough */ 1115 if (unlikely(msg_len < info->attr.mq_msgsize)) { 1116 ret = -EMSGSIZE; 1117 goto out_fput; 1118 } 1119 1120 /* 1121 * msg_insert really wants us to have a valid, spare node struct so 1122 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will 1123 * fall back to that if necessary. 1124 */ 1125 if (!info->node_cache) 1126 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL); 1127 1128 spin_lock(&info->lock); 1129 1130 if (!info->node_cache && new_leaf) { 1131 /* Save our speculative allocation into the cache */ 1132 INIT_LIST_HEAD(&new_leaf->msg_list); 1133 info->node_cache = new_leaf; 1134 info->qsize += sizeof(*new_leaf); 1135 } else { 1136 kfree(new_leaf); 1137 } 1138 1139 if (info->attr.mq_curmsgs == 0) { 1140 if (f.file->f_flags & O_NONBLOCK) { 1141 spin_unlock(&info->lock); 1142 ret = -EAGAIN; 1143 } else { 1144 wait.task = current; 1145 wait.state = STATE_NONE; 1146 ret = wq_sleep(info, RECV, timeout, &wait); 1147 msg_ptr = wait.msg; 1148 } 1149 } else { 1150 msg_ptr = msg_get(info); 1151 1152 inode->i_atime = inode->i_mtime = inode->i_ctime = 1153 CURRENT_TIME; 1154 1155 /* There is now free space in queue. */ 1156 pipelined_receive(info); 1157 spin_unlock(&info->lock); 1158 ret = 0; 1159 } 1160 if (ret == 0) { 1161 ret = msg_ptr->m_ts; 1162 1163 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) || 1164 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) { 1165 ret = -EFAULT; 1166 } 1167 free_msg(msg_ptr); 1168 } 1169 out_fput: 1170 fdput(f); 1171 out: 1172 return ret; 1173 } 1174 1175 /* 1176 * Notes: the case when user wants us to deregister (with NULL as pointer) 1177 * and he isn't currently owner of notification, will be silently discarded. 1178 * It isn't explicitly defined in the POSIX. 1179 */ 1180 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes, 1181 const struct sigevent __user *, u_notification) 1182 { 1183 int ret; 1184 struct fd f; 1185 struct sock *sock; 1186 struct inode *inode; 1187 struct sigevent notification; 1188 struct mqueue_inode_info *info; 1189 struct sk_buff *nc; 1190 1191 if (u_notification) { 1192 if (copy_from_user(¬ification, u_notification, 1193 sizeof(struct sigevent))) 1194 return -EFAULT; 1195 } 1196 1197 audit_mq_notify(mqdes, u_notification ? ¬ification : NULL); 1198 1199 nc = NULL; 1200 sock = NULL; 1201 if (u_notification != NULL) { 1202 if (unlikely(notification.sigev_notify != SIGEV_NONE && 1203 notification.sigev_notify != SIGEV_SIGNAL && 1204 notification.sigev_notify != SIGEV_THREAD)) 1205 return -EINVAL; 1206 if (notification.sigev_notify == SIGEV_SIGNAL && 1207 !valid_signal(notification.sigev_signo)) { 1208 return -EINVAL; 1209 } 1210 if (notification.sigev_notify == SIGEV_THREAD) { 1211 long timeo; 1212 1213 /* create the notify skb */ 1214 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL); 1215 if (!nc) { 1216 ret = -ENOMEM; 1217 goto out; 1218 } 1219 if (copy_from_user(nc->data, 1220 notification.sigev_value.sival_ptr, 1221 NOTIFY_COOKIE_LEN)) { 1222 ret = -EFAULT; 1223 goto out; 1224 } 1225 1226 /* TODO: add a header? */ 1227 skb_put(nc, NOTIFY_COOKIE_LEN); 1228 /* and attach it to the socket */ 1229 retry: 1230 f = fdget(notification.sigev_signo); 1231 if (!f.file) { 1232 ret = -EBADF; 1233 goto out; 1234 } 1235 sock = netlink_getsockbyfilp(f.file); 1236 fdput(f); 1237 if (IS_ERR(sock)) { 1238 ret = PTR_ERR(sock); 1239 sock = NULL; 1240 goto out; 1241 } 1242 1243 timeo = MAX_SCHEDULE_TIMEOUT; 1244 ret = netlink_attachskb(sock, nc, &timeo, NULL); 1245 if (ret == 1) 1246 goto retry; 1247 if (ret) { 1248 sock = NULL; 1249 nc = NULL; 1250 goto out; 1251 } 1252 } 1253 } 1254 1255 f = fdget(mqdes); 1256 if (!f.file) { 1257 ret = -EBADF; 1258 goto out; 1259 } 1260 1261 inode = file_inode(f.file); 1262 if (unlikely(f.file->f_op != &mqueue_file_operations)) { 1263 ret = -EBADF; 1264 goto out_fput; 1265 } 1266 info = MQUEUE_I(inode); 1267 1268 ret = 0; 1269 spin_lock(&info->lock); 1270 if (u_notification == NULL) { 1271 if (info->notify_owner == task_tgid(current)) { 1272 remove_notification(info); 1273 inode->i_atime = inode->i_ctime = CURRENT_TIME; 1274 } 1275 } else if (info->notify_owner != NULL) { 1276 ret = -EBUSY; 1277 } else { 1278 switch (notification.sigev_notify) { 1279 case SIGEV_NONE: 1280 info->notify.sigev_notify = SIGEV_NONE; 1281 break; 1282 case SIGEV_THREAD: 1283 info->notify_sock = sock; 1284 info->notify_cookie = nc; 1285 sock = NULL; 1286 nc = NULL; 1287 info->notify.sigev_notify = SIGEV_THREAD; 1288 break; 1289 case SIGEV_SIGNAL: 1290 info->notify.sigev_signo = notification.sigev_signo; 1291 info->notify.sigev_value = notification.sigev_value; 1292 info->notify.sigev_notify = SIGEV_SIGNAL; 1293 break; 1294 } 1295 1296 info->notify_owner = get_pid(task_tgid(current)); 1297 info->notify_user_ns = get_user_ns(current_user_ns()); 1298 inode->i_atime = inode->i_ctime = CURRENT_TIME; 1299 } 1300 spin_unlock(&info->lock); 1301 out_fput: 1302 fdput(f); 1303 out: 1304 if (sock) { 1305 netlink_detachskb(sock, nc); 1306 } else if (nc) { 1307 dev_kfree_skb(nc); 1308 } 1309 return ret; 1310 } 1311 1312 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes, 1313 const struct mq_attr __user *, u_mqstat, 1314 struct mq_attr __user *, u_omqstat) 1315 { 1316 int ret; 1317 struct mq_attr mqstat, omqstat; 1318 struct fd f; 1319 struct inode *inode; 1320 struct mqueue_inode_info *info; 1321 1322 if (u_mqstat != NULL) { 1323 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr))) 1324 return -EFAULT; 1325 if (mqstat.mq_flags & (~O_NONBLOCK)) 1326 return -EINVAL; 1327 } 1328 1329 f = fdget(mqdes); 1330 if (!f.file) { 1331 ret = -EBADF; 1332 goto out; 1333 } 1334 1335 inode = file_inode(f.file); 1336 if (unlikely(f.file->f_op != &mqueue_file_operations)) { 1337 ret = -EBADF; 1338 goto out_fput; 1339 } 1340 info = MQUEUE_I(inode); 1341 1342 spin_lock(&info->lock); 1343 1344 omqstat = info->attr; 1345 omqstat.mq_flags = f.file->f_flags & O_NONBLOCK; 1346 if (u_mqstat) { 1347 audit_mq_getsetattr(mqdes, &mqstat); 1348 spin_lock(&f.file->f_lock); 1349 if (mqstat.mq_flags & O_NONBLOCK) 1350 f.file->f_flags |= O_NONBLOCK; 1351 else 1352 f.file->f_flags &= ~O_NONBLOCK; 1353 spin_unlock(&f.file->f_lock); 1354 1355 inode->i_atime = inode->i_ctime = CURRENT_TIME; 1356 } 1357 1358 spin_unlock(&info->lock); 1359 1360 ret = 0; 1361 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat, 1362 sizeof(struct mq_attr))) 1363 ret = -EFAULT; 1364 1365 out_fput: 1366 fdput(f); 1367 out: 1368 return ret; 1369 } 1370 1371 static const struct inode_operations mqueue_dir_inode_operations = { 1372 .lookup = simple_lookup, 1373 .create = mqueue_create, 1374 .unlink = mqueue_unlink, 1375 }; 1376 1377 static const struct file_operations mqueue_file_operations = { 1378 .flush = mqueue_flush_file, 1379 .poll = mqueue_poll_file, 1380 .read = mqueue_read_file, 1381 .llseek = default_llseek, 1382 }; 1383 1384 static const struct super_operations mqueue_super_ops = { 1385 .alloc_inode = mqueue_alloc_inode, 1386 .destroy_inode = mqueue_destroy_inode, 1387 .evict_inode = mqueue_evict_inode, 1388 .statfs = simple_statfs, 1389 }; 1390 1391 static struct file_system_type mqueue_fs_type = { 1392 .name = "mqueue", 1393 .mount = mqueue_mount, 1394 .kill_sb = kill_litter_super, 1395 .fs_flags = FS_USERNS_MOUNT, 1396 }; 1397 1398 int mq_init_ns(struct ipc_namespace *ns) 1399 { 1400 ns->mq_queues_count = 0; 1401 ns->mq_queues_max = DFLT_QUEUESMAX; 1402 ns->mq_msg_max = DFLT_MSGMAX; 1403 ns->mq_msgsize_max = DFLT_MSGSIZEMAX; 1404 ns->mq_msg_default = DFLT_MSG; 1405 ns->mq_msgsize_default = DFLT_MSGSIZE; 1406 1407 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns); 1408 if (IS_ERR(ns->mq_mnt)) { 1409 int err = PTR_ERR(ns->mq_mnt); 1410 ns->mq_mnt = NULL; 1411 return err; 1412 } 1413 return 0; 1414 } 1415 1416 void mq_clear_sbinfo(struct ipc_namespace *ns) 1417 { 1418 ns->mq_mnt->mnt_sb->s_fs_info = NULL; 1419 } 1420 1421 void mq_put_mnt(struct ipc_namespace *ns) 1422 { 1423 kern_unmount(ns->mq_mnt); 1424 } 1425 1426 static int __init init_mqueue_fs(void) 1427 { 1428 int error; 1429 1430 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache", 1431 sizeof(struct mqueue_inode_info), 0, 1432 SLAB_HWCACHE_ALIGN, init_once); 1433 if (mqueue_inode_cachep == NULL) 1434 return -ENOMEM; 1435 1436 /* ignore failures - they are not fatal */ 1437 mq_sysctl_table = mq_register_sysctl_table(); 1438 1439 error = register_filesystem(&mqueue_fs_type); 1440 if (error) 1441 goto out_sysctl; 1442 1443 spin_lock_init(&mq_lock); 1444 1445 error = mq_init_ns(&init_ipc_ns); 1446 if (error) 1447 goto out_filesystem; 1448 1449 return 0; 1450 1451 out_filesystem: 1452 unregister_filesystem(&mqueue_fs_type); 1453 out_sysctl: 1454 if (mq_sysctl_table) 1455 unregister_sysctl_table(mq_sysctl_table); 1456 kmem_cache_destroy(mqueue_inode_cachep); 1457 return error; 1458 } 1459 1460 __initcall(init_mqueue_fs); 1461