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 kfree(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 long 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_timeout(timeout); 444 445 while (ewp->state == STATE_PENDING) 446 cpu_relax(); 447 448 if (ewp->state == STATE_READY) { 449 retval = 0; 450 goto out; 451 } 452 spin_lock(&info->lock); 453 if (ewp->state == STATE_READY) { 454 retval = 0; 455 goto out_unlock; 456 } 457 if (signal_pending(current)) { 458 retval = -ERESTARTSYS; 459 break; 460 } 461 if (time == 0) { 462 retval = -ETIMEDOUT; 463 break; 464 } 465 } 466 list_del(&ewp->list); 467 out_unlock: 468 spin_unlock(&info->lock); 469 out: 470 return retval; 471 } 472 473 /* 474 * Returns waiting task that should be serviced first or NULL if none exists 475 */ 476 static struct ext_wait_queue *wq_get_first_waiter( 477 struct mqueue_inode_info *info, int sr) 478 { 479 struct list_head *ptr; 480 481 ptr = info->e_wait_q[sr].list.prev; 482 if (ptr == &info->e_wait_q[sr].list) 483 return NULL; 484 return list_entry(ptr, struct ext_wait_queue, list); 485 } 486 487 /* Auxiliary functions to manipulate messages' list */ 488 static void msg_insert(struct msg_msg *ptr, struct mqueue_inode_info *info) 489 { 490 int k; 491 492 k = info->attr.mq_curmsgs - 1; 493 while (k >= 0 && info->messages[k]->m_type >= ptr->m_type) { 494 info->messages[k + 1] = info->messages[k]; 495 k--; 496 } 497 info->attr.mq_curmsgs++; 498 info->qsize += ptr->m_ts; 499 info->messages[k + 1] = ptr; 500 } 501 502 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info) 503 { 504 info->qsize -= info->messages[--info->attr.mq_curmsgs]->m_ts; 505 return info->messages[info->attr.mq_curmsgs]; 506 } 507 508 static inline void set_cookie(struct sk_buff *skb, char code) 509 { 510 ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code; 511 } 512 513 /* 514 * The next function is only to split too long sys_mq_timedsend 515 */ 516 static void __do_notify(struct mqueue_inode_info *info) 517 { 518 /* notification 519 * invoked when there is registered process and there isn't process 520 * waiting synchronously for message AND state of queue changed from 521 * empty to not empty. Here we are sure that no one is waiting 522 * synchronously. */ 523 if (info->notify_owner && 524 info->attr.mq_curmsgs == 1) { 525 struct siginfo sig_i; 526 switch (info->notify.sigev_notify) { 527 case SIGEV_NONE: 528 break; 529 case SIGEV_SIGNAL: 530 /* sends signal */ 531 532 sig_i.si_signo = info->notify.sigev_signo; 533 sig_i.si_errno = 0; 534 sig_i.si_code = SI_MESGQ; 535 sig_i.si_value = info->notify.sigev_value; 536 sig_i.si_pid = task_tgid_nr_ns(current, 537 ns_of_pid(info->notify_owner)); 538 sig_i.si_uid = current_uid(); 539 540 kill_pid_info(info->notify.sigev_signo, 541 &sig_i, info->notify_owner); 542 break; 543 case SIGEV_THREAD: 544 set_cookie(info->notify_cookie, NOTIFY_WOKENUP); 545 netlink_sendskb(info->notify_sock, info->notify_cookie); 546 break; 547 } 548 /* after notification unregisters process */ 549 put_pid(info->notify_owner); 550 info->notify_owner = NULL; 551 } 552 wake_up(&info->wait_q); 553 } 554 555 static long prepare_timeout(struct timespec *p) 556 { 557 struct timespec nowts; 558 long timeout; 559 560 if (p) { 561 if (unlikely(p->tv_nsec < 0 || p->tv_sec < 0 562 || p->tv_nsec >= NSEC_PER_SEC)) 563 return -EINVAL; 564 nowts = CURRENT_TIME; 565 /* first subtract as jiffies can't be too big */ 566 p->tv_sec -= nowts.tv_sec; 567 if (p->tv_nsec < nowts.tv_nsec) { 568 p->tv_nsec += NSEC_PER_SEC; 569 p->tv_sec--; 570 } 571 p->tv_nsec -= nowts.tv_nsec; 572 if (p->tv_sec < 0) 573 return 0; 574 575 timeout = timespec_to_jiffies(p) + 1; 576 } else 577 return MAX_SCHEDULE_TIMEOUT; 578 579 return timeout; 580 } 581 582 static void remove_notification(struct mqueue_inode_info *info) 583 { 584 if (info->notify_owner != NULL && 585 info->notify.sigev_notify == SIGEV_THREAD) { 586 set_cookie(info->notify_cookie, NOTIFY_REMOVED); 587 netlink_sendskb(info->notify_sock, info->notify_cookie); 588 } 589 put_pid(info->notify_owner); 590 info->notify_owner = NULL; 591 } 592 593 static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr) 594 { 595 if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0) 596 return 0; 597 if (capable(CAP_SYS_RESOURCE)) { 598 if (attr->mq_maxmsg > HARD_MSGMAX) 599 return 0; 600 } else { 601 if (attr->mq_maxmsg > ipc_ns->mq_msg_max || 602 attr->mq_msgsize > ipc_ns->mq_msgsize_max) 603 return 0; 604 } 605 /* check for overflow */ 606 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg) 607 return 0; 608 if ((unsigned long)(attr->mq_maxmsg * (attr->mq_msgsize 609 + sizeof (struct msg_msg *))) < 610 (unsigned long)(attr->mq_maxmsg * attr->mq_msgsize)) 611 return 0; 612 return 1; 613 } 614 615 /* 616 * Invoked when creating a new queue via sys_mq_open 617 */ 618 static struct file *do_create(struct ipc_namespace *ipc_ns, struct dentry *dir, 619 struct dentry *dentry, int oflag, mode_t mode, 620 struct mq_attr *attr) 621 { 622 const struct cred *cred = current_cred(); 623 struct file *result; 624 int ret; 625 626 if (attr) { 627 if (!mq_attr_ok(ipc_ns, attr)) { 628 ret = -EINVAL; 629 goto out; 630 } 631 /* store for use during create */ 632 dentry->d_fsdata = attr; 633 } 634 635 mode &= ~current_umask(); 636 ret = mnt_want_write(ipc_ns->mq_mnt); 637 if (ret) 638 goto out; 639 ret = vfs_create(dir->d_inode, dentry, mode, NULL); 640 dentry->d_fsdata = NULL; 641 if (ret) 642 goto out_drop_write; 643 644 result = dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred); 645 /* 646 * dentry_open() took a persistent mnt_want_write(), 647 * so we can now drop this one. 648 */ 649 mnt_drop_write(ipc_ns->mq_mnt); 650 return result; 651 652 out_drop_write: 653 mnt_drop_write(ipc_ns->mq_mnt); 654 out: 655 dput(dentry); 656 mntput(ipc_ns->mq_mnt); 657 return ERR_PTR(ret); 658 } 659 660 /* Opens existing queue */ 661 static struct file *do_open(struct ipc_namespace *ipc_ns, 662 struct dentry *dentry, int oflag) 663 { 664 int ret; 665 const struct cred *cred = current_cred(); 666 667 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE, 668 MAY_READ | MAY_WRITE }; 669 670 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) { 671 ret = -EINVAL; 672 goto err; 673 } 674 675 if (inode_permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE])) { 676 ret = -EACCES; 677 goto err; 678 } 679 680 return dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred); 681 682 err: 683 dput(dentry); 684 mntput(ipc_ns->mq_mnt); 685 return ERR_PTR(ret); 686 } 687 688 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, mode_t, mode, 689 struct mq_attr __user *, u_attr) 690 { 691 struct dentry *dentry; 692 struct file *filp; 693 char *name; 694 struct mq_attr attr; 695 int fd, error; 696 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; 697 698 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr))) 699 return -EFAULT; 700 701 audit_mq_open(oflag, mode, u_attr ? &attr : NULL); 702 703 if (IS_ERR(name = getname(u_name))) 704 return PTR_ERR(name); 705 706 fd = get_unused_fd_flags(O_CLOEXEC); 707 if (fd < 0) 708 goto out_putname; 709 710 mutex_lock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex); 711 dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name)); 712 if (IS_ERR(dentry)) { 713 error = PTR_ERR(dentry); 714 goto out_putfd; 715 } 716 mntget(ipc_ns->mq_mnt); 717 718 if (oflag & O_CREAT) { 719 if (dentry->d_inode) { /* entry already exists */ 720 audit_inode(name, dentry); 721 if (oflag & O_EXCL) { 722 error = -EEXIST; 723 goto out; 724 } 725 filp = do_open(ipc_ns, dentry, oflag); 726 } else { 727 filp = do_create(ipc_ns, ipc_ns->mq_mnt->mnt_root, 728 dentry, oflag, mode, 729 u_attr ? &attr : NULL); 730 } 731 } else { 732 if (!dentry->d_inode) { 733 error = -ENOENT; 734 goto out; 735 } 736 audit_inode(name, dentry); 737 filp = do_open(ipc_ns, dentry, oflag); 738 } 739 740 if (IS_ERR(filp)) { 741 error = PTR_ERR(filp); 742 goto out_putfd; 743 } 744 745 fd_install(fd, filp); 746 goto out_upsem; 747 748 out: 749 dput(dentry); 750 mntput(ipc_ns->mq_mnt); 751 out_putfd: 752 put_unused_fd(fd); 753 fd = error; 754 out_upsem: 755 mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex); 756 out_putname: 757 putname(name); 758 return fd; 759 } 760 761 SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name) 762 { 763 int err; 764 char *name; 765 struct dentry *dentry; 766 struct inode *inode = NULL; 767 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; 768 769 name = getname(u_name); 770 if (IS_ERR(name)) 771 return PTR_ERR(name); 772 773 mutex_lock_nested(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex, 774 I_MUTEX_PARENT); 775 dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name)); 776 if (IS_ERR(dentry)) { 777 err = PTR_ERR(dentry); 778 goto out_unlock; 779 } 780 781 if (!dentry->d_inode) { 782 err = -ENOENT; 783 goto out_err; 784 } 785 786 inode = dentry->d_inode; 787 if (inode) 788 atomic_inc(&inode->i_count); 789 err = mnt_want_write(ipc_ns->mq_mnt); 790 if (err) 791 goto out_err; 792 err = vfs_unlink(dentry->d_parent->d_inode, dentry); 793 mnt_drop_write(ipc_ns->mq_mnt); 794 out_err: 795 dput(dentry); 796 797 out_unlock: 798 mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex); 799 putname(name); 800 if (inode) 801 iput(inode); 802 803 return err; 804 } 805 806 /* Pipelined send and receive functions. 807 * 808 * If a receiver finds no waiting message, then it registers itself in the 809 * list of waiting receivers. A sender checks that list before adding the new 810 * message into the message array. If there is a waiting receiver, then it 811 * bypasses the message array and directly hands the message over to the 812 * receiver. 813 * The receiver accepts the message and returns without grabbing the queue 814 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers 815 * are necessary. The same algorithm is used for sysv semaphores, see 816 * ipc/sem.c for more details. 817 * 818 * The same algorithm is used for senders. 819 */ 820 821 /* pipelined_send() - send a message directly to the task waiting in 822 * sys_mq_timedreceive() (without inserting message into a queue). 823 */ 824 static inline void pipelined_send(struct mqueue_inode_info *info, 825 struct msg_msg *message, 826 struct ext_wait_queue *receiver) 827 { 828 receiver->msg = message; 829 list_del(&receiver->list); 830 receiver->state = STATE_PENDING; 831 wake_up_process(receiver->task); 832 smp_wmb(); 833 receiver->state = STATE_READY; 834 } 835 836 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend() 837 * gets its message and put to the queue (we have one free place for sure). */ 838 static inline void pipelined_receive(struct mqueue_inode_info *info) 839 { 840 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND); 841 842 if (!sender) { 843 /* for poll */ 844 wake_up_interruptible(&info->wait_q); 845 return; 846 } 847 msg_insert(sender->msg, info); 848 list_del(&sender->list); 849 sender->state = STATE_PENDING; 850 wake_up_process(sender->task); 851 smp_wmb(); 852 sender->state = STATE_READY; 853 } 854 855 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr, 856 size_t, msg_len, unsigned int, msg_prio, 857 const struct timespec __user *, u_abs_timeout) 858 { 859 struct file *filp; 860 struct inode *inode; 861 struct ext_wait_queue wait; 862 struct ext_wait_queue *receiver; 863 struct msg_msg *msg_ptr; 864 struct mqueue_inode_info *info; 865 struct timespec ts, *p = NULL; 866 long timeout; 867 int ret; 868 869 if (u_abs_timeout) { 870 if (copy_from_user(&ts, u_abs_timeout, 871 sizeof(struct timespec))) 872 return -EFAULT; 873 p = &ts; 874 } 875 876 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX)) 877 return -EINVAL; 878 879 audit_mq_sendrecv(mqdes, msg_len, msg_prio, p); 880 timeout = prepare_timeout(p); 881 882 filp = fget(mqdes); 883 if (unlikely(!filp)) { 884 ret = -EBADF; 885 goto out; 886 } 887 888 inode = filp->f_path.dentry->d_inode; 889 if (unlikely(filp->f_op != &mqueue_file_operations)) { 890 ret = -EBADF; 891 goto out_fput; 892 } 893 info = MQUEUE_I(inode); 894 audit_inode(NULL, filp->f_path.dentry); 895 896 if (unlikely(!(filp->f_mode & FMODE_WRITE))) { 897 ret = -EBADF; 898 goto out_fput; 899 } 900 901 if (unlikely(msg_len > info->attr.mq_msgsize)) { 902 ret = -EMSGSIZE; 903 goto out_fput; 904 } 905 906 /* First try to allocate memory, before doing anything with 907 * existing queues. */ 908 msg_ptr = load_msg(u_msg_ptr, msg_len); 909 if (IS_ERR(msg_ptr)) { 910 ret = PTR_ERR(msg_ptr); 911 goto out_fput; 912 } 913 msg_ptr->m_ts = msg_len; 914 msg_ptr->m_type = msg_prio; 915 916 spin_lock(&info->lock); 917 918 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) { 919 if (filp->f_flags & O_NONBLOCK) { 920 spin_unlock(&info->lock); 921 ret = -EAGAIN; 922 } else if (unlikely(timeout < 0)) { 923 spin_unlock(&info->lock); 924 ret = timeout; 925 } else { 926 wait.task = current; 927 wait.msg = (void *) msg_ptr; 928 wait.state = STATE_NONE; 929 ret = wq_sleep(info, SEND, timeout, &wait); 930 } 931 if (ret < 0) 932 free_msg(msg_ptr); 933 } else { 934 receiver = wq_get_first_waiter(info, RECV); 935 if (receiver) { 936 pipelined_send(info, msg_ptr, receiver); 937 } else { 938 /* adds message to the queue */ 939 msg_insert(msg_ptr, info); 940 __do_notify(info); 941 } 942 inode->i_atime = inode->i_mtime = inode->i_ctime = 943 CURRENT_TIME; 944 spin_unlock(&info->lock); 945 ret = 0; 946 } 947 out_fput: 948 fput(filp); 949 out: 950 return ret; 951 } 952 953 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr, 954 size_t, msg_len, unsigned int __user *, u_msg_prio, 955 const struct timespec __user *, u_abs_timeout) 956 { 957 long timeout; 958 ssize_t ret; 959 struct msg_msg *msg_ptr; 960 struct file *filp; 961 struct inode *inode; 962 struct mqueue_inode_info *info; 963 struct ext_wait_queue wait; 964 struct timespec ts, *p = NULL; 965 966 if (u_abs_timeout) { 967 if (copy_from_user(&ts, u_abs_timeout, 968 sizeof(struct timespec))) 969 return -EFAULT; 970 p = &ts; 971 } 972 973 audit_mq_sendrecv(mqdes, msg_len, 0, p); 974 timeout = prepare_timeout(p); 975 976 filp = fget(mqdes); 977 if (unlikely(!filp)) { 978 ret = -EBADF; 979 goto out; 980 } 981 982 inode = filp->f_path.dentry->d_inode; 983 if (unlikely(filp->f_op != &mqueue_file_operations)) { 984 ret = -EBADF; 985 goto out_fput; 986 } 987 info = MQUEUE_I(inode); 988 audit_inode(NULL, filp->f_path.dentry); 989 990 if (unlikely(!(filp->f_mode & FMODE_READ))) { 991 ret = -EBADF; 992 goto out_fput; 993 } 994 995 /* checks if buffer is big enough */ 996 if (unlikely(msg_len < info->attr.mq_msgsize)) { 997 ret = -EMSGSIZE; 998 goto out_fput; 999 } 1000 1001 spin_lock(&info->lock); 1002 if (info->attr.mq_curmsgs == 0) { 1003 if (filp->f_flags & O_NONBLOCK) { 1004 spin_unlock(&info->lock); 1005 ret = -EAGAIN; 1006 msg_ptr = NULL; 1007 } else if (unlikely(timeout < 0)) { 1008 spin_unlock(&info->lock); 1009 ret = timeout; 1010 msg_ptr = NULL; 1011 } else { 1012 wait.task = current; 1013 wait.state = STATE_NONE; 1014 ret = wq_sleep(info, RECV, timeout, &wait); 1015 msg_ptr = wait.msg; 1016 } 1017 } else { 1018 msg_ptr = msg_get(info); 1019 1020 inode->i_atime = inode->i_mtime = inode->i_ctime = 1021 CURRENT_TIME; 1022 1023 /* There is now free space in queue. */ 1024 pipelined_receive(info); 1025 spin_unlock(&info->lock); 1026 ret = 0; 1027 } 1028 if (ret == 0) { 1029 ret = msg_ptr->m_ts; 1030 1031 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) || 1032 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) { 1033 ret = -EFAULT; 1034 } 1035 free_msg(msg_ptr); 1036 } 1037 out_fput: 1038 fput(filp); 1039 out: 1040 return ret; 1041 } 1042 1043 /* 1044 * Notes: the case when user wants us to deregister (with NULL as pointer) 1045 * and he isn't currently owner of notification, will be silently discarded. 1046 * It isn't explicitly defined in the POSIX. 1047 */ 1048 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes, 1049 const struct sigevent __user *, u_notification) 1050 { 1051 int ret; 1052 struct file *filp; 1053 struct sock *sock; 1054 struct inode *inode; 1055 struct sigevent notification; 1056 struct mqueue_inode_info *info; 1057 struct sk_buff *nc; 1058 1059 if (u_notification) { 1060 if (copy_from_user(¬ification, u_notification, 1061 sizeof(struct sigevent))) 1062 return -EFAULT; 1063 } 1064 1065 audit_mq_notify(mqdes, u_notification ? ¬ification : NULL); 1066 1067 nc = NULL; 1068 sock = NULL; 1069 if (u_notification != NULL) { 1070 if (unlikely(notification.sigev_notify != SIGEV_NONE && 1071 notification.sigev_notify != SIGEV_SIGNAL && 1072 notification.sigev_notify != SIGEV_THREAD)) 1073 return -EINVAL; 1074 if (notification.sigev_notify == SIGEV_SIGNAL && 1075 !valid_signal(notification.sigev_signo)) { 1076 return -EINVAL; 1077 } 1078 if (notification.sigev_notify == SIGEV_THREAD) { 1079 long timeo; 1080 1081 /* create the notify skb */ 1082 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL); 1083 if (!nc) { 1084 ret = -ENOMEM; 1085 goto out; 1086 } 1087 if (copy_from_user(nc->data, 1088 notification.sigev_value.sival_ptr, 1089 NOTIFY_COOKIE_LEN)) { 1090 ret = -EFAULT; 1091 goto out; 1092 } 1093 1094 /* TODO: add a header? */ 1095 skb_put(nc, NOTIFY_COOKIE_LEN); 1096 /* and attach it to the socket */ 1097 retry: 1098 filp = fget(notification.sigev_signo); 1099 if (!filp) { 1100 ret = -EBADF; 1101 goto out; 1102 } 1103 sock = netlink_getsockbyfilp(filp); 1104 fput(filp); 1105 if (IS_ERR(sock)) { 1106 ret = PTR_ERR(sock); 1107 sock = NULL; 1108 goto out; 1109 } 1110 1111 timeo = MAX_SCHEDULE_TIMEOUT; 1112 ret = netlink_attachskb(sock, nc, &timeo, NULL); 1113 if (ret == 1) 1114 goto retry; 1115 if (ret) { 1116 sock = NULL; 1117 nc = NULL; 1118 goto out; 1119 } 1120 } 1121 } 1122 1123 filp = fget(mqdes); 1124 if (!filp) { 1125 ret = -EBADF; 1126 goto out; 1127 } 1128 1129 inode = filp->f_path.dentry->d_inode; 1130 if (unlikely(filp->f_op != &mqueue_file_operations)) { 1131 ret = -EBADF; 1132 goto out_fput; 1133 } 1134 info = MQUEUE_I(inode); 1135 1136 ret = 0; 1137 spin_lock(&info->lock); 1138 if (u_notification == NULL) { 1139 if (info->notify_owner == task_tgid(current)) { 1140 remove_notification(info); 1141 inode->i_atime = inode->i_ctime = CURRENT_TIME; 1142 } 1143 } else if (info->notify_owner != NULL) { 1144 ret = -EBUSY; 1145 } else { 1146 switch (notification.sigev_notify) { 1147 case SIGEV_NONE: 1148 info->notify.sigev_notify = SIGEV_NONE; 1149 break; 1150 case SIGEV_THREAD: 1151 info->notify_sock = sock; 1152 info->notify_cookie = nc; 1153 sock = NULL; 1154 nc = NULL; 1155 info->notify.sigev_notify = SIGEV_THREAD; 1156 break; 1157 case SIGEV_SIGNAL: 1158 info->notify.sigev_signo = notification.sigev_signo; 1159 info->notify.sigev_value = notification.sigev_value; 1160 info->notify.sigev_notify = SIGEV_SIGNAL; 1161 break; 1162 } 1163 1164 info->notify_owner = get_pid(task_tgid(current)); 1165 inode->i_atime = inode->i_ctime = CURRENT_TIME; 1166 } 1167 spin_unlock(&info->lock); 1168 out_fput: 1169 fput(filp); 1170 out: 1171 if (sock) { 1172 netlink_detachskb(sock, nc); 1173 } else if (nc) { 1174 dev_kfree_skb(nc); 1175 } 1176 return ret; 1177 } 1178 1179 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes, 1180 const struct mq_attr __user *, u_mqstat, 1181 struct mq_attr __user *, u_omqstat) 1182 { 1183 int ret; 1184 struct mq_attr mqstat, omqstat; 1185 struct file *filp; 1186 struct inode *inode; 1187 struct mqueue_inode_info *info; 1188 1189 if (u_mqstat != NULL) { 1190 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr))) 1191 return -EFAULT; 1192 if (mqstat.mq_flags & (~O_NONBLOCK)) 1193 return -EINVAL; 1194 } 1195 1196 filp = fget(mqdes); 1197 if (!filp) { 1198 ret = -EBADF; 1199 goto out; 1200 } 1201 1202 inode = filp->f_path.dentry->d_inode; 1203 if (unlikely(filp->f_op != &mqueue_file_operations)) { 1204 ret = -EBADF; 1205 goto out_fput; 1206 } 1207 info = MQUEUE_I(inode); 1208 1209 spin_lock(&info->lock); 1210 1211 omqstat = info->attr; 1212 omqstat.mq_flags = filp->f_flags & O_NONBLOCK; 1213 if (u_mqstat) { 1214 audit_mq_getsetattr(mqdes, &mqstat); 1215 spin_lock(&filp->f_lock); 1216 if (mqstat.mq_flags & O_NONBLOCK) 1217 filp->f_flags |= O_NONBLOCK; 1218 else 1219 filp->f_flags &= ~O_NONBLOCK; 1220 spin_unlock(&filp->f_lock); 1221 1222 inode->i_atime = inode->i_ctime = CURRENT_TIME; 1223 } 1224 1225 spin_unlock(&info->lock); 1226 1227 ret = 0; 1228 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat, 1229 sizeof(struct mq_attr))) 1230 ret = -EFAULT; 1231 1232 out_fput: 1233 fput(filp); 1234 out: 1235 return ret; 1236 } 1237 1238 static const struct inode_operations mqueue_dir_inode_operations = { 1239 .lookup = simple_lookup, 1240 .create = mqueue_create, 1241 .unlink = mqueue_unlink, 1242 }; 1243 1244 static const struct file_operations mqueue_file_operations = { 1245 .flush = mqueue_flush_file, 1246 .poll = mqueue_poll_file, 1247 .read = mqueue_read_file, 1248 }; 1249 1250 static const struct super_operations mqueue_super_ops = { 1251 .alloc_inode = mqueue_alloc_inode, 1252 .destroy_inode = mqueue_destroy_inode, 1253 .statfs = simple_statfs, 1254 .delete_inode = mqueue_delete_inode, 1255 .drop_inode = generic_delete_inode, 1256 }; 1257 1258 static struct file_system_type mqueue_fs_type = { 1259 .name = "mqueue", 1260 .get_sb = mqueue_get_sb, 1261 .kill_sb = kill_litter_super, 1262 }; 1263 1264 int mq_init_ns(struct ipc_namespace *ns) 1265 { 1266 ns->mq_queues_count = 0; 1267 ns->mq_queues_max = DFLT_QUEUESMAX; 1268 ns->mq_msg_max = DFLT_MSGMAX; 1269 ns->mq_msgsize_max = DFLT_MSGSIZEMAX; 1270 1271 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns); 1272 if (IS_ERR(ns->mq_mnt)) { 1273 int err = PTR_ERR(ns->mq_mnt); 1274 ns->mq_mnt = NULL; 1275 return err; 1276 } 1277 return 0; 1278 } 1279 1280 void mq_clear_sbinfo(struct ipc_namespace *ns) 1281 { 1282 ns->mq_mnt->mnt_sb->s_fs_info = NULL; 1283 } 1284 1285 void mq_put_mnt(struct ipc_namespace *ns) 1286 { 1287 mntput(ns->mq_mnt); 1288 } 1289 1290 static int __init init_mqueue_fs(void) 1291 { 1292 int error; 1293 1294 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache", 1295 sizeof(struct mqueue_inode_info), 0, 1296 SLAB_HWCACHE_ALIGN, init_once); 1297 if (mqueue_inode_cachep == NULL) 1298 return -ENOMEM; 1299 1300 /* ignore failures - they are not fatal */ 1301 mq_sysctl_table = mq_register_sysctl_table(); 1302 1303 error = register_filesystem(&mqueue_fs_type); 1304 if (error) 1305 goto out_sysctl; 1306 1307 spin_lock_init(&mq_lock); 1308 1309 init_ipc_ns.mq_mnt = kern_mount_data(&mqueue_fs_type, &init_ipc_ns); 1310 if (IS_ERR(init_ipc_ns.mq_mnt)) { 1311 error = PTR_ERR(init_ipc_ns.mq_mnt); 1312 goto out_filesystem; 1313 } 1314 1315 return 0; 1316 1317 out_filesystem: 1318 unregister_filesystem(&mqueue_fs_type); 1319 out_sysctl: 1320 if (mq_sysctl_table) 1321 unregister_sysctl_table(mq_sysctl_table); 1322 kmem_cache_destroy(mqueue_inode_cachep); 1323 return error; 1324 } 1325 1326 __initcall(init_mqueue_fs); 1327