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_READY 1 51 52 struct posix_msg_tree_node { 53 struct rb_node rb_node; 54 struct list_head msg_list; 55 int priority; 56 }; 57 58 struct ext_wait_queue { /* queue of sleeping tasks */ 59 struct task_struct *task; 60 struct list_head list; 61 struct msg_msg *msg; /* ptr of loaded message */ 62 int state; /* one of STATE_* values */ 63 }; 64 65 struct mqueue_inode_info { 66 spinlock_t lock; 67 struct inode vfs_inode; 68 wait_queue_head_t wait_q; 69 70 struct rb_root msg_tree; 71 struct posix_msg_tree_node *node_cache; 72 struct mq_attr attr; 73 74 struct sigevent notify; 75 struct pid *notify_owner; 76 struct user_namespace *notify_user_ns; 77 struct user_struct *user; /* user who created, for accounting */ 78 struct sock *notify_sock; 79 struct sk_buff *notify_cookie; 80 81 /* for tasks waiting for free space and messages, respectively */ 82 struct ext_wait_queue e_wait_q[2]; 83 84 unsigned long qsize; /* size of queue in memory (sum of all msgs) */ 85 }; 86 87 static const struct inode_operations mqueue_dir_inode_operations; 88 static const struct file_operations mqueue_file_operations; 89 static const struct super_operations mqueue_super_ops; 90 static void remove_notification(struct mqueue_inode_info *info); 91 92 static struct kmem_cache *mqueue_inode_cachep; 93 94 static struct ctl_table_header *mq_sysctl_table; 95 96 static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode) 97 { 98 return container_of(inode, struct mqueue_inode_info, vfs_inode); 99 } 100 101 /* 102 * This routine should be called with the mq_lock held. 103 */ 104 static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode) 105 { 106 return get_ipc_ns(inode->i_sb->s_fs_info); 107 } 108 109 static struct ipc_namespace *get_ns_from_inode(struct inode *inode) 110 { 111 struct ipc_namespace *ns; 112 113 spin_lock(&mq_lock); 114 ns = __get_ns_from_inode(inode); 115 spin_unlock(&mq_lock); 116 return ns; 117 } 118 119 /* Auxiliary functions to manipulate messages' list */ 120 static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info) 121 { 122 struct rb_node **p, *parent = NULL; 123 struct posix_msg_tree_node *leaf; 124 125 p = &info->msg_tree.rb_node; 126 while (*p) { 127 parent = *p; 128 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node); 129 130 if (likely(leaf->priority == msg->m_type)) 131 goto insert_msg; 132 else if (msg->m_type < leaf->priority) 133 p = &(*p)->rb_left; 134 else 135 p = &(*p)->rb_right; 136 } 137 if (info->node_cache) { 138 leaf = info->node_cache; 139 info->node_cache = NULL; 140 } else { 141 leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC); 142 if (!leaf) 143 return -ENOMEM; 144 INIT_LIST_HEAD(&leaf->msg_list); 145 } 146 leaf->priority = msg->m_type; 147 rb_link_node(&leaf->rb_node, parent, p); 148 rb_insert_color(&leaf->rb_node, &info->msg_tree); 149 insert_msg: 150 info->attr.mq_curmsgs++; 151 info->qsize += msg->m_ts; 152 list_add_tail(&msg->m_list, &leaf->msg_list); 153 return 0; 154 } 155 156 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info) 157 { 158 struct rb_node **p, *parent = NULL; 159 struct posix_msg_tree_node *leaf; 160 struct msg_msg *msg; 161 162 try_again: 163 p = &info->msg_tree.rb_node; 164 while (*p) { 165 parent = *p; 166 /* 167 * During insert, low priorities go to the left and high to the 168 * right. On receive, we want the highest priorities first, so 169 * walk all the way to the right. 170 */ 171 p = &(*p)->rb_right; 172 } 173 if (!parent) { 174 if (info->attr.mq_curmsgs) { 175 pr_warn_once("Inconsistency in POSIX message queue, " 176 "no tree element, but supposedly messages " 177 "should exist!\n"); 178 info->attr.mq_curmsgs = 0; 179 } 180 return NULL; 181 } 182 leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node); 183 if (unlikely(list_empty(&leaf->msg_list))) { 184 pr_warn_once("Inconsistency in POSIX message queue, " 185 "empty leaf node but we haven't implemented " 186 "lazy leaf delete!\n"); 187 rb_erase(&leaf->rb_node, &info->msg_tree); 188 if (info->node_cache) { 189 kfree(leaf); 190 } else { 191 info->node_cache = leaf; 192 } 193 goto try_again; 194 } else { 195 msg = list_first_entry(&leaf->msg_list, 196 struct msg_msg, m_list); 197 list_del(&msg->m_list); 198 if (list_empty(&leaf->msg_list)) { 199 rb_erase(&leaf->rb_node, &info->msg_tree); 200 if (info->node_cache) { 201 kfree(leaf); 202 } else { 203 info->node_cache = leaf; 204 } 205 } 206 } 207 info->attr.mq_curmsgs--; 208 info->qsize -= msg->m_ts; 209 return msg; 210 } 211 212 static struct inode *mqueue_get_inode(struct super_block *sb, 213 struct ipc_namespace *ipc_ns, umode_t mode, 214 struct mq_attr *attr) 215 { 216 struct user_struct *u = current_user(); 217 struct inode *inode; 218 int ret = -ENOMEM; 219 220 inode = new_inode(sb); 221 if (!inode) 222 goto err; 223 224 inode->i_ino = get_next_ino(); 225 inode->i_mode = mode; 226 inode->i_uid = current_fsuid(); 227 inode->i_gid = current_fsgid(); 228 inode->i_mtime = inode->i_ctime = inode->i_atime = CURRENT_TIME; 229 230 if (S_ISREG(mode)) { 231 struct mqueue_inode_info *info; 232 unsigned long mq_bytes, mq_treesize; 233 234 inode->i_fop = &mqueue_file_operations; 235 inode->i_size = FILENT_SIZE; 236 /* mqueue specific info */ 237 info = MQUEUE_I(inode); 238 spin_lock_init(&info->lock); 239 init_waitqueue_head(&info->wait_q); 240 INIT_LIST_HEAD(&info->e_wait_q[0].list); 241 INIT_LIST_HEAD(&info->e_wait_q[1].list); 242 info->notify_owner = NULL; 243 info->notify_user_ns = NULL; 244 info->qsize = 0; 245 info->user = NULL; /* set when all is ok */ 246 info->msg_tree = RB_ROOT; 247 info->node_cache = NULL; 248 memset(&info->attr, 0, sizeof(info->attr)); 249 info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max, 250 ipc_ns->mq_msg_default); 251 info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max, 252 ipc_ns->mq_msgsize_default); 253 if (attr) { 254 info->attr.mq_maxmsg = attr->mq_maxmsg; 255 info->attr.mq_msgsize = attr->mq_msgsize; 256 } 257 /* 258 * We used to allocate a static array of pointers and account 259 * the size of that array as well as one msg_msg struct per 260 * possible message into the queue size. That's no longer 261 * accurate as the queue is now an rbtree and will grow and 262 * shrink depending on usage patterns. We can, however, still 263 * account one msg_msg struct per message, but the nodes are 264 * allocated depending on priority usage, and most programs 265 * only use one, or a handful, of priorities. However, since 266 * this is pinned memory, we need to assume worst case, so 267 * that means the min(mq_maxmsg, max_priorities) * struct 268 * posix_msg_tree_node. 269 */ 270 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) + 271 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) * 272 sizeof(struct posix_msg_tree_node); 273 274 mq_bytes = mq_treesize + (info->attr.mq_maxmsg * 275 info->attr.mq_msgsize); 276 277 spin_lock(&mq_lock); 278 if (u->mq_bytes + mq_bytes < u->mq_bytes || 279 u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) { 280 spin_unlock(&mq_lock); 281 /* mqueue_evict_inode() releases info->messages */ 282 ret = -EMFILE; 283 goto out_inode; 284 } 285 u->mq_bytes += mq_bytes; 286 spin_unlock(&mq_lock); 287 288 /* all is ok */ 289 info->user = get_uid(u); 290 } else if (S_ISDIR(mode)) { 291 inc_nlink(inode); 292 /* Some things misbehave if size == 0 on a directory */ 293 inode->i_size = 2 * DIRENT_SIZE; 294 inode->i_op = &mqueue_dir_inode_operations; 295 inode->i_fop = &simple_dir_operations; 296 } 297 298 return inode; 299 out_inode: 300 iput(inode); 301 err: 302 return ERR_PTR(ret); 303 } 304 305 static int mqueue_fill_super(struct super_block *sb, void *data, int silent) 306 { 307 struct inode *inode; 308 struct ipc_namespace *ns = data; 309 310 sb->s_blocksize = PAGE_CACHE_SIZE; 311 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 312 sb->s_magic = MQUEUE_MAGIC; 313 sb->s_op = &mqueue_super_ops; 314 315 inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL); 316 if (IS_ERR(inode)) 317 return PTR_ERR(inode); 318 319 sb->s_root = d_make_root(inode); 320 if (!sb->s_root) 321 return -ENOMEM; 322 return 0; 323 } 324 325 static struct dentry *mqueue_mount(struct file_system_type *fs_type, 326 int flags, const char *dev_name, 327 void *data) 328 { 329 if (!(flags & MS_KERNMOUNT)) { 330 struct ipc_namespace *ns = current->nsproxy->ipc_ns; 331 /* Don't allow mounting unless the caller has CAP_SYS_ADMIN 332 * over the ipc namespace. 333 */ 334 if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN)) 335 return ERR_PTR(-EPERM); 336 337 data = ns; 338 } 339 return mount_ns(fs_type, flags, data, mqueue_fill_super); 340 } 341 342 static void init_once(void *foo) 343 { 344 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo; 345 346 inode_init_once(&p->vfs_inode); 347 } 348 349 static struct inode *mqueue_alloc_inode(struct super_block *sb) 350 { 351 struct mqueue_inode_info *ei; 352 353 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL); 354 if (!ei) 355 return NULL; 356 return &ei->vfs_inode; 357 } 358 359 static void mqueue_i_callback(struct rcu_head *head) 360 { 361 struct inode *inode = container_of(head, struct inode, i_rcu); 362 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode)); 363 } 364 365 static void mqueue_destroy_inode(struct inode *inode) 366 { 367 call_rcu(&inode->i_rcu, mqueue_i_callback); 368 } 369 370 static void mqueue_evict_inode(struct inode *inode) 371 { 372 struct mqueue_inode_info *info; 373 struct user_struct *user; 374 unsigned long mq_bytes, mq_treesize; 375 struct ipc_namespace *ipc_ns; 376 struct msg_msg *msg; 377 378 clear_inode(inode); 379 380 if (S_ISDIR(inode->i_mode)) 381 return; 382 383 ipc_ns = get_ns_from_inode(inode); 384 info = MQUEUE_I(inode); 385 spin_lock(&info->lock); 386 while ((msg = msg_get(info)) != NULL) 387 free_msg(msg); 388 kfree(info->node_cache); 389 spin_unlock(&info->lock); 390 391 /* Total amount of bytes accounted for the mqueue */ 392 mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) + 393 min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) * 394 sizeof(struct posix_msg_tree_node); 395 396 mq_bytes = mq_treesize + (info->attr.mq_maxmsg * 397 info->attr.mq_msgsize); 398 399 user = info->user; 400 if (user) { 401 spin_lock(&mq_lock); 402 user->mq_bytes -= mq_bytes; 403 /* 404 * get_ns_from_inode() ensures that the 405 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns 406 * to which we now hold a reference, or it is NULL. 407 * We can't put it here under mq_lock, though. 408 */ 409 if (ipc_ns) 410 ipc_ns->mq_queues_count--; 411 spin_unlock(&mq_lock); 412 free_uid(user); 413 } 414 if (ipc_ns) 415 put_ipc_ns(ipc_ns); 416 } 417 418 static int mqueue_create(struct inode *dir, struct dentry *dentry, 419 umode_t mode, bool excl) 420 { 421 struct inode *inode; 422 struct mq_attr *attr = dentry->d_fsdata; 423 int error; 424 struct ipc_namespace *ipc_ns; 425 426 spin_lock(&mq_lock); 427 ipc_ns = __get_ns_from_inode(dir); 428 if (!ipc_ns) { 429 error = -EACCES; 430 goto out_unlock; 431 } 432 433 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max && 434 !capable(CAP_SYS_RESOURCE)) { 435 error = -ENOSPC; 436 goto out_unlock; 437 } 438 ipc_ns->mq_queues_count++; 439 spin_unlock(&mq_lock); 440 441 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr); 442 if (IS_ERR(inode)) { 443 error = PTR_ERR(inode); 444 spin_lock(&mq_lock); 445 ipc_ns->mq_queues_count--; 446 goto out_unlock; 447 } 448 449 put_ipc_ns(ipc_ns); 450 dir->i_size += DIRENT_SIZE; 451 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME; 452 453 d_instantiate(dentry, inode); 454 dget(dentry); 455 return 0; 456 out_unlock: 457 spin_unlock(&mq_lock); 458 if (ipc_ns) 459 put_ipc_ns(ipc_ns); 460 return error; 461 } 462 463 static int mqueue_unlink(struct inode *dir, struct dentry *dentry) 464 { 465 struct inode *inode = d_inode(dentry); 466 467 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME; 468 dir->i_size -= DIRENT_SIZE; 469 drop_nlink(inode); 470 dput(dentry); 471 return 0; 472 } 473 474 /* 475 * This is routine for system read from queue file. 476 * To avoid mess with doing here some sort of mq_receive we allow 477 * to read only queue size & notification info (the only values 478 * that are interesting from user point of view and aren't accessible 479 * through std routines) 480 */ 481 static ssize_t mqueue_read_file(struct file *filp, char __user *u_data, 482 size_t count, loff_t *off) 483 { 484 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp)); 485 char buffer[FILENT_SIZE]; 486 ssize_t ret; 487 488 spin_lock(&info->lock); 489 snprintf(buffer, sizeof(buffer), 490 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n", 491 info->qsize, 492 info->notify_owner ? info->notify.sigev_notify : 0, 493 (info->notify_owner && 494 info->notify.sigev_notify == SIGEV_SIGNAL) ? 495 info->notify.sigev_signo : 0, 496 pid_vnr(info->notify_owner)); 497 spin_unlock(&info->lock); 498 buffer[sizeof(buffer)-1] = '\0'; 499 500 ret = simple_read_from_buffer(u_data, count, off, buffer, 501 strlen(buffer)); 502 if (ret <= 0) 503 return ret; 504 505 file_inode(filp)->i_atime = file_inode(filp)->i_ctime = CURRENT_TIME; 506 return ret; 507 } 508 509 static int mqueue_flush_file(struct file *filp, fl_owner_t id) 510 { 511 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp)); 512 513 spin_lock(&info->lock); 514 if (task_tgid(current) == info->notify_owner) 515 remove_notification(info); 516 517 spin_unlock(&info->lock); 518 return 0; 519 } 520 521 static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab) 522 { 523 struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp)); 524 int retval = 0; 525 526 poll_wait(filp, &info->wait_q, poll_tab); 527 528 spin_lock(&info->lock); 529 if (info->attr.mq_curmsgs) 530 retval = POLLIN | POLLRDNORM; 531 532 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg) 533 retval |= POLLOUT | POLLWRNORM; 534 spin_unlock(&info->lock); 535 536 return retval; 537 } 538 539 /* Adds current to info->e_wait_q[sr] before element with smaller prio */ 540 static void wq_add(struct mqueue_inode_info *info, int sr, 541 struct ext_wait_queue *ewp) 542 { 543 struct ext_wait_queue *walk; 544 545 ewp->task = current; 546 547 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) { 548 if (walk->task->static_prio <= current->static_prio) { 549 list_add_tail(&ewp->list, &walk->list); 550 return; 551 } 552 } 553 list_add_tail(&ewp->list, &info->e_wait_q[sr].list); 554 } 555 556 /* 557 * Puts current task to sleep. Caller must hold queue lock. After return 558 * lock isn't held. 559 * sr: SEND or RECV 560 */ 561 static int wq_sleep(struct mqueue_inode_info *info, int sr, 562 ktime_t *timeout, struct ext_wait_queue *ewp) 563 { 564 int retval; 565 signed long time; 566 567 wq_add(info, sr, ewp); 568 569 for (;;) { 570 __set_current_state(TASK_INTERRUPTIBLE); 571 572 spin_unlock(&info->lock); 573 time = schedule_hrtimeout_range_clock(timeout, 0, 574 HRTIMER_MODE_ABS, CLOCK_REALTIME); 575 576 if (ewp->state == STATE_READY) { 577 retval = 0; 578 goto out; 579 } 580 spin_lock(&info->lock); 581 if (ewp->state == STATE_READY) { 582 retval = 0; 583 goto out_unlock; 584 } 585 if (signal_pending(current)) { 586 retval = -ERESTARTSYS; 587 break; 588 } 589 if (time == 0) { 590 retval = -ETIMEDOUT; 591 break; 592 } 593 } 594 list_del(&ewp->list); 595 out_unlock: 596 spin_unlock(&info->lock); 597 out: 598 return retval; 599 } 600 601 /* 602 * Returns waiting task that should be serviced first or NULL if none exists 603 */ 604 static struct ext_wait_queue *wq_get_first_waiter( 605 struct mqueue_inode_info *info, int sr) 606 { 607 struct list_head *ptr; 608 609 ptr = info->e_wait_q[sr].list.prev; 610 if (ptr == &info->e_wait_q[sr].list) 611 return NULL; 612 return list_entry(ptr, struct ext_wait_queue, list); 613 } 614 615 616 static inline void set_cookie(struct sk_buff *skb, char code) 617 { 618 ((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code; 619 } 620 621 /* 622 * The next function is only to split too long sys_mq_timedsend 623 */ 624 static void __do_notify(struct mqueue_inode_info *info) 625 { 626 /* notification 627 * invoked when there is registered process and there isn't process 628 * waiting synchronously for message AND state of queue changed from 629 * empty to not empty. Here we are sure that no one is waiting 630 * synchronously. */ 631 if (info->notify_owner && 632 info->attr.mq_curmsgs == 1) { 633 struct siginfo sig_i; 634 switch (info->notify.sigev_notify) { 635 case SIGEV_NONE: 636 break; 637 case SIGEV_SIGNAL: 638 /* sends signal */ 639 640 sig_i.si_signo = info->notify.sigev_signo; 641 sig_i.si_errno = 0; 642 sig_i.si_code = SI_MESGQ; 643 sig_i.si_value = info->notify.sigev_value; 644 /* map current pid/uid into info->owner's namespaces */ 645 rcu_read_lock(); 646 sig_i.si_pid = task_tgid_nr_ns(current, 647 ns_of_pid(info->notify_owner)); 648 sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid()); 649 rcu_read_unlock(); 650 651 kill_pid_info(info->notify.sigev_signo, 652 &sig_i, info->notify_owner); 653 break; 654 case SIGEV_THREAD: 655 set_cookie(info->notify_cookie, NOTIFY_WOKENUP); 656 netlink_sendskb(info->notify_sock, info->notify_cookie); 657 break; 658 } 659 /* after notification unregisters process */ 660 put_pid(info->notify_owner); 661 put_user_ns(info->notify_user_ns); 662 info->notify_owner = NULL; 663 info->notify_user_ns = NULL; 664 } 665 wake_up(&info->wait_q); 666 } 667 668 static int prepare_timeout(const struct timespec __user *u_abs_timeout, 669 ktime_t *expires, struct timespec *ts) 670 { 671 if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec))) 672 return -EFAULT; 673 if (!timespec_valid(ts)) 674 return -EINVAL; 675 676 *expires = timespec_to_ktime(*ts); 677 return 0; 678 } 679 680 static void remove_notification(struct mqueue_inode_info *info) 681 { 682 if (info->notify_owner != NULL && 683 info->notify.sigev_notify == SIGEV_THREAD) { 684 set_cookie(info->notify_cookie, NOTIFY_REMOVED); 685 netlink_sendskb(info->notify_sock, info->notify_cookie); 686 } 687 put_pid(info->notify_owner); 688 put_user_ns(info->notify_user_ns); 689 info->notify_owner = NULL; 690 info->notify_user_ns = NULL; 691 } 692 693 static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr) 694 { 695 int mq_treesize; 696 unsigned long total_size; 697 698 if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0) 699 return -EINVAL; 700 if (capable(CAP_SYS_RESOURCE)) { 701 if (attr->mq_maxmsg > HARD_MSGMAX || 702 attr->mq_msgsize > HARD_MSGSIZEMAX) 703 return -EINVAL; 704 } else { 705 if (attr->mq_maxmsg > ipc_ns->mq_msg_max || 706 attr->mq_msgsize > ipc_ns->mq_msgsize_max) 707 return -EINVAL; 708 } 709 /* check for overflow */ 710 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg) 711 return -EOVERFLOW; 712 mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) + 713 min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) * 714 sizeof(struct posix_msg_tree_node); 715 total_size = attr->mq_maxmsg * attr->mq_msgsize; 716 if (total_size + mq_treesize < total_size) 717 return -EOVERFLOW; 718 return 0; 719 } 720 721 /* 722 * Invoked when creating a new queue via sys_mq_open 723 */ 724 static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir, 725 struct path *path, int oflag, umode_t mode, 726 struct mq_attr *attr) 727 { 728 const struct cred *cred = current_cred(); 729 int ret; 730 731 if (attr) { 732 ret = mq_attr_ok(ipc_ns, attr); 733 if (ret) 734 return ERR_PTR(ret); 735 /* store for use during create */ 736 path->dentry->d_fsdata = attr; 737 } else { 738 struct mq_attr def_attr; 739 740 def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max, 741 ipc_ns->mq_msg_default); 742 def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max, 743 ipc_ns->mq_msgsize_default); 744 ret = mq_attr_ok(ipc_ns, &def_attr); 745 if (ret) 746 return ERR_PTR(ret); 747 } 748 749 mode &= ~current_umask(); 750 ret = vfs_create(dir, path->dentry, mode, true); 751 path->dentry->d_fsdata = NULL; 752 if (ret) 753 return ERR_PTR(ret); 754 return dentry_open(path, oflag, cred); 755 } 756 757 /* Opens existing queue */ 758 static struct file *do_open(struct path *path, int oflag) 759 { 760 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE, 761 MAY_READ | MAY_WRITE }; 762 int acc; 763 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) 764 return ERR_PTR(-EINVAL); 765 acc = oflag2acc[oflag & O_ACCMODE]; 766 if (inode_permission(d_inode(path->dentry), acc)) 767 return ERR_PTR(-EACCES); 768 return dentry_open(path, oflag, current_cred()); 769 } 770 771 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode, 772 struct mq_attr __user *, u_attr) 773 { 774 struct path path; 775 struct file *filp; 776 struct filename *name; 777 struct mq_attr attr; 778 int fd, error; 779 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; 780 struct vfsmount *mnt = ipc_ns->mq_mnt; 781 struct dentry *root = mnt->mnt_root; 782 int ro; 783 784 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr))) 785 return -EFAULT; 786 787 audit_mq_open(oflag, mode, u_attr ? &attr : NULL); 788 789 if (IS_ERR(name = getname(u_name))) 790 return PTR_ERR(name); 791 792 fd = get_unused_fd_flags(O_CLOEXEC); 793 if (fd < 0) 794 goto out_putname; 795 796 ro = mnt_want_write(mnt); /* we'll drop it in any case */ 797 error = 0; 798 mutex_lock(&d_inode(root)->i_mutex); 799 path.dentry = lookup_one_len(name->name, root, strlen(name->name)); 800 if (IS_ERR(path.dentry)) { 801 error = PTR_ERR(path.dentry); 802 goto out_putfd; 803 } 804 path.mnt = mntget(mnt); 805 806 if (oflag & O_CREAT) { 807 if (d_really_is_positive(path.dentry)) { /* entry already exists */ 808 audit_inode(name, path.dentry, 0); 809 if (oflag & O_EXCL) { 810 error = -EEXIST; 811 goto out; 812 } 813 filp = do_open(&path, oflag); 814 } else { 815 if (ro) { 816 error = ro; 817 goto out; 818 } 819 audit_inode_parent_hidden(name, root); 820 filp = do_create(ipc_ns, d_inode(root), 821 &path, oflag, mode, 822 u_attr ? &attr : NULL); 823 } 824 } else { 825 if (d_really_is_negative(path.dentry)) { 826 error = -ENOENT; 827 goto out; 828 } 829 audit_inode(name, path.dentry, 0); 830 filp = do_open(&path, oflag); 831 } 832 833 if (!IS_ERR(filp)) 834 fd_install(fd, filp); 835 else 836 error = PTR_ERR(filp); 837 out: 838 path_put(&path); 839 out_putfd: 840 if (error) { 841 put_unused_fd(fd); 842 fd = error; 843 } 844 mutex_unlock(&d_inode(root)->i_mutex); 845 if (!ro) 846 mnt_drop_write(mnt); 847 out_putname: 848 putname(name); 849 return fd; 850 } 851 852 SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name) 853 { 854 int err; 855 struct filename *name; 856 struct dentry *dentry; 857 struct inode *inode = NULL; 858 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; 859 struct vfsmount *mnt = ipc_ns->mq_mnt; 860 861 name = getname(u_name); 862 if (IS_ERR(name)) 863 return PTR_ERR(name); 864 865 audit_inode_parent_hidden(name, mnt->mnt_root); 866 err = mnt_want_write(mnt); 867 if (err) 868 goto out_name; 869 mutex_lock_nested(&d_inode(mnt->mnt_root)->i_mutex, I_MUTEX_PARENT); 870 dentry = lookup_one_len(name->name, mnt->mnt_root, 871 strlen(name->name)); 872 if (IS_ERR(dentry)) { 873 err = PTR_ERR(dentry); 874 goto out_unlock; 875 } 876 877 inode = d_inode(dentry); 878 if (!inode) { 879 err = -ENOENT; 880 } else { 881 ihold(inode); 882 err = vfs_unlink(d_inode(dentry->d_parent), dentry, NULL); 883 } 884 dput(dentry); 885 886 out_unlock: 887 mutex_unlock(&d_inode(mnt->mnt_root)->i_mutex); 888 if (inode) 889 iput(inode); 890 mnt_drop_write(mnt); 891 out_name: 892 putname(name); 893 894 return err; 895 } 896 897 /* Pipelined send and receive functions. 898 * 899 * If a receiver finds no waiting message, then it registers itself in the 900 * list of waiting receivers. A sender checks that list before adding the new 901 * message into the message array. If there is a waiting receiver, then it 902 * bypasses the message array and directly hands the message over to the 903 * receiver. The receiver accepts the message and returns without grabbing the 904 * queue spinlock: 905 * 906 * - Set pointer to message. 907 * - Queue the receiver task for later wakeup (without the info->lock). 908 * - Update its state to STATE_READY. Now the receiver can continue. 909 * - Wake up the process after the lock is dropped. Should the process wake up 910 * before this wakeup (due to a timeout or a signal) it will either see 911 * STATE_READY and continue or acquire the lock to check the state again. 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 */ 919 static inline void pipelined_send(struct wake_q_head *wake_q, 920 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 wake_q_add(wake_q, receiver->task); 927 /* 928 * Rely on the implicit cmpxchg barrier from wake_q_add such 929 * that we can ensure that updating receiver->state is the last 930 * write operation: As once set, the receiver can continue, 931 * and if we don't have the reference count from the wake_q, 932 * yet, at that point we can later have a use-after-free 933 * condition and bogus wakeup. 934 */ 935 receiver->state = STATE_READY; 936 } 937 938 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend() 939 * gets its message and put to the queue (we have one free place for sure). */ 940 static inline void pipelined_receive(struct wake_q_head *wake_q, 941 struct mqueue_inode_info *info) 942 { 943 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND); 944 945 if (!sender) { 946 /* for poll */ 947 wake_up_interruptible(&info->wait_q); 948 return; 949 } 950 if (msg_insert(sender->msg, info)) 951 return; 952 953 list_del(&sender->list); 954 wake_q_add(wake_q, sender->task); 955 sender->state = STATE_READY; 956 } 957 958 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr, 959 size_t, msg_len, unsigned int, msg_prio, 960 const struct timespec __user *, u_abs_timeout) 961 { 962 struct fd f; 963 struct inode *inode; 964 struct ext_wait_queue wait; 965 struct ext_wait_queue *receiver; 966 struct msg_msg *msg_ptr; 967 struct mqueue_inode_info *info; 968 ktime_t expires, *timeout = NULL; 969 struct timespec ts; 970 struct posix_msg_tree_node *new_leaf = NULL; 971 int ret = 0; 972 WAKE_Q(wake_q); 973 974 if (u_abs_timeout) { 975 int res = prepare_timeout(u_abs_timeout, &expires, &ts); 976 if (res) 977 return res; 978 timeout = &expires; 979 } 980 981 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX)) 982 return -EINVAL; 983 984 audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL); 985 986 f = fdget(mqdes); 987 if (unlikely(!f.file)) { 988 ret = -EBADF; 989 goto out; 990 } 991 992 inode = file_inode(f.file); 993 if (unlikely(f.file->f_op != &mqueue_file_operations)) { 994 ret = -EBADF; 995 goto out_fput; 996 } 997 info = MQUEUE_I(inode); 998 audit_file(f.file); 999 1000 if (unlikely(!(f.file->f_mode & FMODE_WRITE))) { 1001 ret = -EBADF; 1002 goto out_fput; 1003 } 1004 1005 if (unlikely(msg_len > info->attr.mq_msgsize)) { 1006 ret = -EMSGSIZE; 1007 goto out_fput; 1008 } 1009 1010 /* First try to allocate memory, before doing anything with 1011 * existing queues. */ 1012 msg_ptr = load_msg(u_msg_ptr, msg_len); 1013 if (IS_ERR(msg_ptr)) { 1014 ret = PTR_ERR(msg_ptr); 1015 goto out_fput; 1016 } 1017 msg_ptr->m_ts = msg_len; 1018 msg_ptr->m_type = msg_prio; 1019 1020 /* 1021 * msg_insert really wants us to have a valid, spare node struct so 1022 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will 1023 * fall back to that if necessary. 1024 */ 1025 if (!info->node_cache) 1026 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL); 1027 1028 spin_lock(&info->lock); 1029 1030 if (!info->node_cache && new_leaf) { 1031 /* Save our speculative allocation into the cache */ 1032 INIT_LIST_HEAD(&new_leaf->msg_list); 1033 info->node_cache = new_leaf; 1034 new_leaf = NULL; 1035 } else { 1036 kfree(new_leaf); 1037 } 1038 1039 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) { 1040 if (f.file->f_flags & O_NONBLOCK) { 1041 ret = -EAGAIN; 1042 } else { 1043 wait.task = current; 1044 wait.msg = (void *) msg_ptr; 1045 wait.state = STATE_NONE; 1046 ret = wq_sleep(info, SEND, timeout, &wait); 1047 /* 1048 * wq_sleep must be called with info->lock held, and 1049 * returns with the lock released 1050 */ 1051 goto out_free; 1052 } 1053 } else { 1054 receiver = wq_get_first_waiter(info, RECV); 1055 if (receiver) { 1056 pipelined_send(&wake_q, info, msg_ptr, receiver); 1057 } else { 1058 /* adds message to the queue */ 1059 ret = msg_insert(msg_ptr, info); 1060 if (ret) 1061 goto out_unlock; 1062 __do_notify(info); 1063 } 1064 inode->i_atime = inode->i_mtime = inode->i_ctime = 1065 CURRENT_TIME; 1066 } 1067 out_unlock: 1068 spin_unlock(&info->lock); 1069 wake_up_q(&wake_q); 1070 out_free: 1071 if (ret) 1072 free_msg(msg_ptr); 1073 out_fput: 1074 fdput(f); 1075 out: 1076 return ret; 1077 } 1078 1079 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr, 1080 size_t, msg_len, unsigned int __user *, u_msg_prio, 1081 const struct timespec __user *, u_abs_timeout) 1082 { 1083 ssize_t ret; 1084 struct msg_msg *msg_ptr; 1085 struct fd f; 1086 struct inode *inode; 1087 struct mqueue_inode_info *info; 1088 struct ext_wait_queue wait; 1089 ktime_t expires, *timeout = NULL; 1090 struct timespec ts; 1091 struct posix_msg_tree_node *new_leaf = NULL; 1092 1093 if (u_abs_timeout) { 1094 int res = prepare_timeout(u_abs_timeout, &expires, &ts); 1095 if (res) 1096 return res; 1097 timeout = &expires; 1098 } 1099 1100 audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL); 1101 1102 f = fdget(mqdes); 1103 if (unlikely(!f.file)) { 1104 ret = -EBADF; 1105 goto out; 1106 } 1107 1108 inode = file_inode(f.file); 1109 if (unlikely(f.file->f_op != &mqueue_file_operations)) { 1110 ret = -EBADF; 1111 goto out_fput; 1112 } 1113 info = MQUEUE_I(inode); 1114 audit_file(f.file); 1115 1116 if (unlikely(!(f.file->f_mode & FMODE_READ))) { 1117 ret = -EBADF; 1118 goto out_fput; 1119 } 1120 1121 /* checks if buffer is big enough */ 1122 if (unlikely(msg_len < info->attr.mq_msgsize)) { 1123 ret = -EMSGSIZE; 1124 goto out_fput; 1125 } 1126 1127 /* 1128 * msg_insert really wants us to have a valid, spare node struct so 1129 * it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will 1130 * fall back to that if necessary. 1131 */ 1132 if (!info->node_cache) 1133 new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL); 1134 1135 spin_lock(&info->lock); 1136 1137 if (!info->node_cache && new_leaf) { 1138 /* Save our speculative allocation into the cache */ 1139 INIT_LIST_HEAD(&new_leaf->msg_list); 1140 info->node_cache = new_leaf; 1141 } else { 1142 kfree(new_leaf); 1143 } 1144 1145 if (info->attr.mq_curmsgs == 0) { 1146 if (f.file->f_flags & O_NONBLOCK) { 1147 spin_unlock(&info->lock); 1148 ret = -EAGAIN; 1149 } else { 1150 wait.task = current; 1151 wait.state = STATE_NONE; 1152 ret = wq_sleep(info, RECV, timeout, &wait); 1153 msg_ptr = wait.msg; 1154 } 1155 } else { 1156 WAKE_Q(wake_q); 1157 1158 msg_ptr = msg_get(info); 1159 1160 inode->i_atime = inode->i_mtime = inode->i_ctime = 1161 CURRENT_TIME; 1162 1163 /* There is now free space in queue. */ 1164 pipelined_receive(&wake_q, info); 1165 spin_unlock(&info->lock); 1166 wake_up_q(&wake_q); 1167 ret = 0; 1168 } 1169 if (ret == 0) { 1170 ret = msg_ptr->m_ts; 1171 1172 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) || 1173 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) { 1174 ret = -EFAULT; 1175 } 1176 free_msg(msg_ptr); 1177 } 1178 out_fput: 1179 fdput(f); 1180 out: 1181 return ret; 1182 } 1183 1184 /* 1185 * Notes: the case when user wants us to deregister (with NULL as pointer) 1186 * and he isn't currently owner of notification, will be silently discarded. 1187 * It isn't explicitly defined in the POSIX. 1188 */ 1189 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes, 1190 const struct sigevent __user *, u_notification) 1191 { 1192 int ret; 1193 struct fd f; 1194 struct sock *sock; 1195 struct inode *inode; 1196 struct sigevent notification; 1197 struct mqueue_inode_info *info; 1198 struct sk_buff *nc; 1199 1200 if (u_notification) { 1201 if (copy_from_user(¬ification, u_notification, 1202 sizeof(struct sigevent))) 1203 return -EFAULT; 1204 } 1205 1206 audit_mq_notify(mqdes, u_notification ? ¬ification : NULL); 1207 1208 nc = NULL; 1209 sock = NULL; 1210 if (u_notification != NULL) { 1211 if (unlikely(notification.sigev_notify != SIGEV_NONE && 1212 notification.sigev_notify != SIGEV_SIGNAL && 1213 notification.sigev_notify != SIGEV_THREAD)) 1214 return -EINVAL; 1215 if (notification.sigev_notify == SIGEV_SIGNAL && 1216 !valid_signal(notification.sigev_signo)) { 1217 return -EINVAL; 1218 } 1219 if (notification.sigev_notify == SIGEV_THREAD) { 1220 long timeo; 1221 1222 /* create the notify skb */ 1223 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL); 1224 if (!nc) { 1225 ret = -ENOMEM; 1226 goto out; 1227 } 1228 if (copy_from_user(nc->data, 1229 notification.sigev_value.sival_ptr, 1230 NOTIFY_COOKIE_LEN)) { 1231 ret = -EFAULT; 1232 goto out; 1233 } 1234 1235 /* TODO: add a header? */ 1236 skb_put(nc, NOTIFY_COOKIE_LEN); 1237 /* and attach it to the socket */ 1238 retry: 1239 f = fdget(notification.sigev_signo); 1240 if (!f.file) { 1241 ret = -EBADF; 1242 goto out; 1243 } 1244 sock = netlink_getsockbyfilp(f.file); 1245 fdput(f); 1246 if (IS_ERR(sock)) { 1247 ret = PTR_ERR(sock); 1248 sock = NULL; 1249 goto out; 1250 } 1251 1252 timeo = MAX_SCHEDULE_TIMEOUT; 1253 ret = netlink_attachskb(sock, nc, &timeo, NULL); 1254 if (ret == 1) 1255 goto retry; 1256 if (ret) { 1257 sock = NULL; 1258 nc = NULL; 1259 goto out; 1260 } 1261 } 1262 } 1263 1264 f = fdget(mqdes); 1265 if (!f.file) { 1266 ret = -EBADF; 1267 goto out; 1268 } 1269 1270 inode = file_inode(f.file); 1271 if (unlikely(f.file->f_op != &mqueue_file_operations)) { 1272 ret = -EBADF; 1273 goto out_fput; 1274 } 1275 info = MQUEUE_I(inode); 1276 1277 ret = 0; 1278 spin_lock(&info->lock); 1279 if (u_notification == NULL) { 1280 if (info->notify_owner == task_tgid(current)) { 1281 remove_notification(info); 1282 inode->i_atime = inode->i_ctime = CURRENT_TIME; 1283 } 1284 } else if (info->notify_owner != NULL) { 1285 ret = -EBUSY; 1286 } else { 1287 switch (notification.sigev_notify) { 1288 case SIGEV_NONE: 1289 info->notify.sigev_notify = SIGEV_NONE; 1290 break; 1291 case SIGEV_THREAD: 1292 info->notify_sock = sock; 1293 info->notify_cookie = nc; 1294 sock = NULL; 1295 nc = NULL; 1296 info->notify.sigev_notify = SIGEV_THREAD; 1297 break; 1298 case SIGEV_SIGNAL: 1299 info->notify.sigev_signo = notification.sigev_signo; 1300 info->notify.sigev_value = notification.sigev_value; 1301 info->notify.sigev_notify = SIGEV_SIGNAL; 1302 break; 1303 } 1304 1305 info->notify_owner = get_pid(task_tgid(current)); 1306 info->notify_user_ns = get_user_ns(current_user_ns()); 1307 inode->i_atime = inode->i_ctime = CURRENT_TIME; 1308 } 1309 spin_unlock(&info->lock); 1310 out_fput: 1311 fdput(f); 1312 out: 1313 if (sock) 1314 netlink_detachskb(sock, nc); 1315 else if (nc) 1316 dev_kfree_skb(nc); 1317 1318 return ret; 1319 } 1320 1321 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes, 1322 const struct mq_attr __user *, u_mqstat, 1323 struct mq_attr __user *, u_omqstat) 1324 { 1325 int ret; 1326 struct mq_attr mqstat, omqstat; 1327 struct fd f; 1328 struct inode *inode; 1329 struct mqueue_inode_info *info; 1330 1331 if (u_mqstat != NULL) { 1332 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr))) 1333 return -EFAULT; 1334 if (mqstat.mq_flags & (~O_NONBLOCK)) 1335 return -EINVAL; 1336 } 1337 1338 f = fdget(mqdes); 1339 if (!f.file) { 1340 ret = -EBADF; 1341 goto out; 1342 } 1343 1344 inode = file_inode(f.file); 1345 if (unlikely(f.file->f_op != &mqueue_file_operations)) { 1346 ret = -EBADF; 1347 goto out_fput; 1348 } 1349 info = MQUEUE_I(inode); 1350 1351 spin_lock(&info->lock); 1352 1353 omqstat = info->attr; 1354 omqstat.mq_flags = f.file->f_flags & O_NONBLOCK; 1355 if (u_mqstat) { 1356 audit_mq_getsetattr(mqdes, &mqstat); 1357 spin_lock(&f.file->f_lock); 1358 if (mqstat.mq_flags & O_NONBLOCK) 1359 f.file->f_flags |= O_NONBLOCK; 1360 else 1361 f.file->f_flags &= ~O_NONBLOCK; 1362 spin_unlock(&f.file->f_lock); 1363 1364 inode->i_atime = inode->i_ctime = CURRENT_TIME; 1365 } 1366 1367 spin_unlock(&info->lock); 1368 1369 ret = 0; 1370 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat, 1371 sizeof(struct mq_attr))) 1372 ret = -EFAULT; 1373 1374 out_fput: 1375 fdput(f); 1376 out: 1377 return ret; 1378 } 1379 1380 static const struct inode_operations mqueue_dir_inode_operations = { 1381 .lookup = simple_lookup, 1382 .create = mqueue_create, 1383 .unlink = mqueue_unlink, 1384 }; 1385 1386 static const struct file_operations mqueue_file_operations = { 1387 .flush = mqueue_flush_file, 1388 .poll = mqueue_poll_file, 1389 .read = mqueue_read_file, 1390 .llseek = default_llseek, 1391 }; 1392 1393 static const struct super_operations mqueue_super_ops = { 1394 .alloc_inode = mqueue_alloc_inode, 1395 .destroy_inode = mqueue_destroy_inode, 1396 .evict_inode = mqueue_evict_inode, 1397 .statfs = simple_statfs, 1398 }; 1399 1400 static struct file_system_type mqueue_fs_type = { 1401 .name = "mqueue", 1402 .mount = mqueue_mount, 1403 .kill_sb = kill_litter_super, 1404 .fs_flags = FS_USERNS_MOUNT, 1405 }; 1406 1407 int mq_init_ns(struct ipc_namespace *ns) 1408 { 1409 ns->mq_queues_count = 0; 1410 ns->mq_queues_max = DFLT_QUEUESMAX; 1411 ns->mq_msg_max = DFLT_MSGMAX; 1412 ns->mq_msgsize_max = DFLT_MSGSIZEMAX; 1413 ns->mq_msg_default = DFLT_MSG; 1414 ns->mq_msgsize_default = DFLT_MSGSIZE; 1415 1416 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns); 1417 if (IS_ERR(ns->mq_mnt)) { 1418 int err = PTR_ERR(ns->mq_mnt); 1419 ns->mq_mnt = NULL; 1420 return err; 1421 } 1422 return 0; 1423 } 1424 1425 void mq_clear_sbinfo(struct ipc_namespace *ns) 1426 { 1427 ns->mq_mnt->mnt_sb->s_fs_info = NULL; 1428 } 1429 1430 void mq_put_mnt(struct ipc_namespace *ns) 1431 { 1432 kern_unmount(ns->mq_mnt); 1433 } 1434 1435 static int __init init_mqueue_fs(void) 1436 { 1437 int error; 1438 1439 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache", 1440 sizeof(struct mqueue_inode_info), 0, 1441 SLAB_HWCACHE_ALIGN, init_once); 1442 if (mqueue_inode_cachep == NULL) 1443 return -ENOMEM; 1444 1445 /* ignore failures - they are not fatal */ 1446 mq_sysctl_table = mq_register_sysctl_table(); 1447 1448 error = register_filesystem(&mqueue_fs_type); 1449 if (error) 1450 goto out_sysctl; 1451 1452 spin_lock_init(&mq_lock); 1453 1454 error = mq_init_ns(&init_ipc_ns); 1455 if (error) 1456 goto out_filesystem; 1457 1458 return 0; 1459 1460 out_filesystem: 1461 unregister_filesystem(&mqueue_fs_type); 1462 out_sysctl: 1463 if (mq_sysctl_table) 1464 unregister_sysctl_table(mq_sysctl_table); 1465 kmem_cache_destroy(mqueue_inode_cachep); 1466 return error; 1467 } 1468 1469 device_initcall(init_mqueue_fs); 1470