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