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