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