mqueue.c revision 04db0dde0ee1c29110642dff57fba9e438eb805c
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 50struct 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 57struct 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 77static const struct inode_operations mqueue_dir_inode_operations; 78static const struct file_operations mqueue_file_operations; 79static const struct super_operations mqueue_super_ops; 80static void remove_notification(struct mqueue_inode_info *info); 81 82static struct kmem_cache *mqueue_inode_cachep; 83 84static struct ctl_table_header * mq_sysctl_table; 85 86static 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 */ 94static 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 99static 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 109static 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->notify_owner = NULL; 138 info->qsize = 0; 139 info->user = NULL; /* set when all is ok */ 140 memset(&info->attr, 0, sizeof(info->attr)); 141 info->attr.mq_maxmsg = ipc_ns->mq_msg_max; 142 info->attr.mq_msgsize = ipc_ns->mq_msgsize_max; 143 if (attr) { 144 info->attr.mq_maxmsg = attr->mq_maxmsg; 145 info->attr.mq_msgsize = attr->mq_msgsize; 146 } 147 mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *); 148 info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL); 149 if (!info->messages) 150 goto out_inode; 151 152 mq_bytes = (mq_msg_tblsz + 153 (info->attr.mq_maxmsg * info->attr.mq_msgsize)); 154 155 spin_lock(&mq_lock); 156 if (u->mq_bytes + mq_bytes < u->mq_bytes || 157 u->mq_bytes + mq_bytes > 158 p->signal->rlim[RLIMIT_MSGQUEUE].rlim_cur) { 159 spin_unlock(&mq_lock); 160 kfree(info->messages); 161 goto out_inode; 162 } 163 u->mq_bytes += mq_bytes; 164 spin_unlock(&mq_lock); 165 166 /* all is ok */ 167 info->user = get_uid(u); 168 } else if (S_ISDIR(mode)) { 169 inc_nlink(inode); 170 /* Some things misbehave if size == 0 on a directory */ 171 inode->i_size = 2 * DIRENT_SIZE; 172 inode->i_op = &mqueue_dir_inode_operations; 173 inode->i_fop = &simple_dir_operations; 174 } 175 } 176 return inode; 177out_inode: 178 make_bad_inode(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 = 0; 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 } 206 207out: 208 return error; 209} 210 211static int mqueue_get_sb(struct file_system_type *fs_type, 212 int flags, const char *dev_name, 213 void *data, struct vfsmount *mnt) 214{ 215 if (!(flags & MS_KERNMOUNT)) 216 data = current->nsproxy->ipc_ns; 217 return get_sb_ns(fs_type, flags, data, mqueue_fill_super, mnt); 218} 219 220static void init_once(void *foo) 221{ 222 struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo; 223 224 inode_init_once(&p->vfs_inode); 225} 226 227static struct inode *mqueue_alloc_inode(struct super_block *sb) 228{ 229 struct mqueue_inode_info *ei; 230 231 ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL); 232 if (!ei) 233 return NULL; 234 return &ei->vfs_inode; 235} 236 237static void mqueue_destroy_inode(struct inode *inode) 238{ 239 kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode)); 240} 241 242static void mqueue_delete_inode(struct inode *inode) 243{ 244 struct mqueue_inode_info *info; 245 struct user_struct *user; 246 unsigned long mq_bytes; 247 int i; 248 struct ipc_namespace *ipc_ns; 249 250 if (S_ISDIR(inode->i_mode)) { 251 clear_inode(inode); 252 return; 253 } 254 ipc_ns = get_ns_from_inode(inode); 255 info = MQUEUE_I(inode); 256 spin_lock(&info->lock); 257 for (i = 0; i < info->attr.mq_curmsgs; i++) 258 free_msg(info->messages[i]); 259 kfree(info->messages); 260 spin_unlock(&info->lock); 261 262 clear_inode(inode); 263 264 /* Total amount of bytes accounted for the mqueue */ 265 mq_bytes = info->attr.mq_maxmsg * (sizeof(struct msg_msg *) 266 + info->attr.mq_msgsize); 267 user = info->user; 268 if (user) { 269 spin_lock(&mq_lock); 270 user->mq_bytes -= mq_bytes; 271 /* 272 * get_ns_from_inode() ensures that the 273 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns 274 * to which we now hold a reference, or it is NULL. 275 * We can't put it here under mq_lock, though. 276 */ 277 if (ipc_ns) 278 ipc_ns->mq_queues_count--; 279 spin_unlock(&mq_lock); 280 free_uid(user); 281 } 282 if (ipc_ns) 283 put_ipc_ns(ipc_ns); 284} 285 286static int mqueue_create(struct inode *dir, struct dentry *dentry, 287 int mode, struct nameidata *nd) 288{ 289 struct inode *inode; 290 struct mq_attr *attr = dentry->d_fsdata; 291 int error; 292 struct ipc_namespace *ipc_ns; 293 294 spin_lock(&mq_lock); 295 ipc_ns = __get_ns_from_inode(dir); 296 if (!ipc_ns) { 297 error = -EACCES; 298 goto out_unlock; 299 } 300 if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max && 301 !capable(CAP_SYS_RESOURCE)) { 302 error = -ENOSPC; 303 goto out_unlock; 304 } 305 ipc_ns->mq_queues_count++; 306 spin_unlock(&mq_lock); 307 308 inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr); 309 if (!inode) { 310 error = -ENOMEM; 311 spin_lock(&mq_lock); 312 ipc_ns->mq_queues_count--; 313 goto out_unlock; 314 } 315 316 put_ipc_ns(ipc_ns); 317 dir->i_size += DIRENT_SIZE; 318 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME; 319 320 d_instantiate(dentry, inode); 321 dget(dentry); 322 return 0; 323out_unlock: 324 spin_unlock(&mq_lock); 325 if (ipc_ns) 326 put_ipc_ns(ipc_ns); 327 return error; 328} 329 330static int mqueue_unlink(struct inode *dir, struct dentry *dentry) 331{ 332 struct inode *inode = dentry->d_inode; 333 334 dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME; 335 dir->i_size -= DIRENT_SIZE; 336 drop_nlink(inode); 337 dput(dentry); 338 return 0; 339} 340 341/* 342* This is routine for system read from queue file. 343* To avoid mess with doing here some sort of mq_receive we allow 344* to read only queue size & notification info (the only values 345* that are interesting from user point of view and aren't accessible 346* through std routines) 347*/ 348static ssize_t mqueue_read_file(struct file *filp, char __user *u_data, 349 size_t count, loff_t *off) 350{ 351 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode); 352 char buffer[FILENT_SIZE]; 353 ssize_t ret; 354 355 spin_lock(&info->lock); 356 snprintf(buffer, sizeof(buffer), 357 "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n", 358 info->qsize, 359 info->notify_owner ? info->notify.sigev_notify : 0, 360 (info->notify_owner && 361 info->notify.sigev_notify == SIGEV_SIGNAL) ? 362 info->notify.sigev_signo : 0, 363 pid_vnr(info->notify_owner)); 364 spin_unlock(&info->lock); 365 buffer[sizeof(buffer)-1] = '\0'; 366 367 ret = simple_read_from_buffer(u_data, count, off, buffer, 368 strlen(buffer)); 369 if (ret <= 0) 370 return ret; 371 372 filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME; 373 return ret; 374} 375 376static int mqueue_flush_file(struct file *filp, fl_owner_t id) 377{ 378 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode); 379 380 spin_lock(&info->lock); 381 if (task_tgid(current) == info->notify_owner) 382 remove_notification(info); 383 384 spin_unlock(&info->lock); 385 return 0; 386} 387 388static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab) 389{ 390 struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode); 391 int retval = 0; 392 393 poll_wait(filp, &info->wait_q, poll_tab); 394 395 spin_lock(&info->lock); 396 if (info->attr.mq_curmsgs) 397 retval = POLLIN | POLLRDNORM; 398 399 if (info->attr.mq_curmsgs < info->attr.mq_maxmsg) 400 retval |= POLLOUT | POLLWRNORM; 401 spin_unlock(&info->lock); 402 403 return retval; 404} 405 406/* Adds current to info->e_wait_q[sr] before element with smaller prio */ 407static void wq_add(struct mqueue_inode_info *info, int sr, 408 struct ext_wait_queue *ewp) 409{ 410 struct ext_wait_queue *walk; 411 412 ewp->task = current; 413 414 list_for_each_entry(walk, &info->e_wait_q[sr].list, list) { 415 if (walk->task->static_prio <= current->static_prio) { 416 list_add_tail(&ewp->list, &walk->list); 417 return; 418 } 419 } 420 list_add_tail(&ewp->list, &info->e_wait_q[sr].list); 421} 422 423/* 424 * Puts current task to sleep. Caller must hold queue lock. After return 425 * lock isn't held. 426 * sr: SEND or RECV 427 */ 428static int wq_sleep(struct mqueue_inode_info *info, int sr, 429 long timeout, struct ext_wait_queue *ewp) 430{ 431 int retval; 432 signed long time; 433 434 wq_add(info, sr, ewp); 435 436 for (;;) { 437 set_current_state(TASK_INTERRUPTIBLE); 438 439 spin_unlock(&info->lock); 440 time = schedule_timeout(timeout); 441 442 while (ewp->state == STATE_PENDING) 443 cpu_relax(); 444 445 if (ewp->state == STATE_READY) { 446 retval = 0; 447 goto out; 448 } 449 spin_lock(&info->lock); 450 if (ewp->state == STATE_READY) { 451 retval = 0; 452 goto out_unlock; 453 } 454 if (signal_pending(current)) { 455 retval = -ERESTARTSYS; 456 break; 457 } 458 if (time == 0) { 459 retval = -ETIMEDOUT; 460 break; 461 } 462 } 463 list_del(&ewp->list); 464out_unlock: 465 spin_unlock(&info->lock); 466out: 467 return retval; 468} 469 470/* 471 * Returns waiting task that should be serviced first or NULL if none exists 472 */ 473static struct ext_wait_queue *wq_get_first_waiter( 474 struct mqueue_inode_info *info, int sr) 475{ 476 struct list_head *ptr; 477 478 ptr = info->e_wait_q[sr].list.prev; 479 if (ptr == &info->e_wait_q[sr].list) 480 return NULL; 481 return list_entry(ptr, struct ext_wait_queue, list); 482} 483 484/* Auxiliary functions to manipulate messages' list */ 485static void msg_insert(struct msg_msg *ptr, struct mqueue_inode_info *info) 486{ 487 int k; 488 489 k = info->attr.mq_curmsgs - 1; 490 while (k >= 0 && info->messages[k]->m_type >= ptr->m_type) { 491 info->messages[k + 1] = info->messages[k]; 492 k--; 493 } 494 info->attr.mq_curmsgs++; 495 info->qsize += ptr->m_ts; 496 info->messages[k + 1] = ptr; 497} 498 499static inline struct msg_msg *msg_get(struct mqueue_inode_info *info) 500{ 501 info->qsize -= info->messages[--info->attr.mq_curmsgs]->m_ts; 502 return info->messages[info->attr.mq_curmsgs]; 503} 504 505static inline void set_cookie(struct sk_buff *skb, char code) 506{ 507 ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code; 508} 509 510/* 511 * The next function is only to split too long sys_mq_timedsend 512 */ 513static void __do_notify(struct mqueue_inode_info *info) 514{ 515 /* notification 516 * invoked when there is registered process and there isn't process 517 * waiting synchronously for message AND state of queue changed from 518 * empty to not empty. Here we are sure that no one is waiting 519 * synchronously. */ 520 if (info->notify_owner && 521 info->attr.mq_curmsgs == 1) { 522 struct siginfo sig_i; 523 switch (info->notify.sigev_notify) { 524 case SIGEV_NONE: 525 break; 526 case SIGEV_SIGNAL: 527 /* sends signal */ 528 529 sig_i.si_signo = info->notify.sigev_signo; 530 sig_i.si_errno = 0; 531 sig_i.si_code = SI_MESGQ; 532 sig_i.si_value = info->notify.sigev_value; 533 sig_i.si_pid = task_tgid_nr_ns(current, 534 ns_of_pid(info->notify_owner)); 535 sig_i.si_uid = current_uid(); 536 537 kill_pid_info(info->notify.sigev_signo, 538 &sig_i, info->notify_owner); 539 break; 540 case SIGEV_THREAD: 541 set_cookie(info->notify_cookie, NOTIFY_WOKENUP); 542 netlink_sendskb(info->notify_sock, info->notify_cookie); 543 break; 544 } 545 /* after notification unregisters process */ 546 put_pid(info->notify_owner); 547 info->notify_owner = NULL; 548 } 549 wake_up(&info->wait_q); 550} 551 552static long prepare_timeout(struct timespec *p) 553{ 554 struct timespec nowts; 555 long timeout; 556 557 if (p) { 558 if (unlikely(p->tv_nsec < 0 || p->tv_sec < 0 559 || p->tv_nsec >= NSEC_PER_SEC)) 560 return -EINVAL; 561 nowts = CURRENT_TIME; 562 /* first subtract as jiffies can't be too big */ 563 p->tv_sec -= nowts.tv_sec; 564 if (p->tv_nsec < nowts.tv_nsec) { 565 p->tv_nsec += NSEC_PER_SEC; 566 p->tv_sec--; 567 } 568 p->tv_nsec -= nowts.tv_nsec; 569 if (p->tv_sec < 0) 570 return 0; 571 572 timeout = timespec_to_jiffies(p) + 1; 573 } else 574 return MAX_SCHEDULE_TIMEOUT; 575 576 return timeout; 577} 578 579static void remove_notification(struct mqueue_inode_info *info) 580{ 581 if (info->notify_owner != NULL && 582 info->notify.sigev_notify == SIGEV_THREAD) { 583 set_cookie(info->notify_cookie, NOTIFY_REMOVED); 584 netlink_sendskb(info->notify_sock, info->notify_cookie); 585 } 586 put_pid(info->notify_owner); 587 info->notify_owner = NULL; 588} 589 590static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr) 591{ 592 if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0) 593 return 0; 594 if (capable(CAP_SYS_RESOURCE)) { 595 if (attr->mq_maxmsg > HARD_MSGMAX) 596 return 0; 597 } else { 598 if (attr->mq_maxmsg > ipc_ns->mq_msg_max || 599 attr->mq_msgsize > ipc_ns->mq_msgsize_max) 600 return 0; 601 } 602 /* check for overflow */ 603 if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg) 604 return 0; 605 if ((unsigned long)(attr->mq_maxmsg * (attr->mq_msgsize 606 + sizeof (struct msg_msg *))) < 607 (unsigned long)(attr->mq_maxmsg * attr->mq_msgsize)) 608 return 0; 609 return 1; 610} 611 612/* 613 * Invoked when creating a new queue via sys_mq_open 614 */ 615static struct file *do_create(struct ipc_namespace *ipc_ns, struct dentry *dir, 616 struct dentry *dentry, int oflag, mode_t mode, 617 struct mq_attr *attr) 618{ 619 const struct cred *cred = current_cred(); 620 struct file *result; 621 int ret; 622 623 if (attr) { 624 ret = -EINVAL; 625 if (!mq_attr_ok(ipc_ns, attr)) 626 goto out; 627 /* store for use during create */ 628 dentry->d_fsdata = attr; 629 } 630 631 mode &= ~current_umask(); 632 ret = mnt_want_write(ipc_ns->mq_mnt); 633 if (ret) 634 goto out; 635 ret = vfs_create(dir->d_inode, dentry, mode, NULL); 636 dentry->d_fsdata = NULL; 637 if (ret) 638 goto out_drop_write; 639 640 result = dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred); 641 /* 642 * dentry_open() took a persistent mnt_want_write(), 643 * so we can now drop this one. 644 */ 645 mnt_drop_write(ipc_ns->mq_mnt); 646 return result; 647 648out_drop_write: 649 mnt_drop_write(ipc_ns->mq_mnt); 650out: 651 dput(dentry); 652 mntput(ipc_ns->mq_mnt); 653 return ERR_PTR(ret); 654} 655 656/* Opens existing queue */ 657static struct file *do_open(struct ipc_namespace *ipc_ns, 658 struct dentry *dentry, int oflag) 659{ 660 int ret; 661 const struct cred *cred = current_cred(); 662 663 static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE, 664 MAY_READ | MAY_WRITE }; 665 666 if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) { 667 ret = -EINVAL; 668 goto err; 669 } 670 671 if (inode_permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE])) { 672 ret = -EACCES; 673 goto err; 674 } 675 676 return dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred); 677 678err: 679 dput(dentry); 680 mntput(ipc_ns->mq_mnt); 681 return ERR_PTR(ret); 682} 683 684SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, mode_t, mode, 685 struct mq_attr __user *, u_attr) 686{ 687 struct dentry *dentry; 688 struct file *filp; 689 char *name; 690 struct mq_attr attr; 691 int fd, error; 692 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; 693 694 if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr))) 695 return -EFAULT; 696 697 audit_mq_open(oflag, mode, u_attr ? &attr : NULL); 698 699 if (IS_ERR(name = getname(u_name))) 700 return PTR_ERR(name); 701 702 fd = get_unused_fd_flags(O_CLOEXEC); 703 if (fd < 0) 704 goto out_putname; 705 706 mutex_lock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex); 707 dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name)); 708 if (IS_ERR(dentry)) { 709 error = PTR_ERR(dentry); 710 goto out_putfd; 711 } 712 mntget(ipc_ns->mq_mnt); 713 714 if (oflag & O_CREAT) { 715 if (dentry->d_inode) { /* entry already exists */ 716 audit_inode(name, dentry); 717 error = -EEXIST; 718 if (oflag & O_EXCL) 719 goto out; 720 filp = do_open(ipc_ns, dentry, oflag); 721 } else { 722 filp = do_create(ipc_ns, ipc_ns->mq_mnt->mnt_root, 723 dentry, oflag, mode, 724 u_attr ? &attr : NULL); 725 } 726 } else { 727 error = -ENOENT; 728 if (!dentry->d_inode) 729 goto out; 730 audit_inode(name, dentry); 731 filp = do_open(ipc_ns, dentry, oflag); 732 } 733 734 if (IS_ERR(filp)) { 735 error = PTR_ERR(filp); 736 goto out_putfd; 737 } 738 739 fd_install(fd, filp); 740 goto out_upsem; 741 742out: 743 dput(dentry); 744 mntput(ipc_ns->mq_mnt); 745out_putfd: 746 put_unused_fd(fd); 747 fd = error; 748out_upsem: 749 mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex); 750out_putname: 751 putname(name); 752 return fd; 753} 754 755SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name) 756{ 757 int err; 758 char *name; 759 struct dentry *dentry; 760 struct inode *inode = NULL; 761 struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns; 762 763 name = getname(u_name); 764 if (IS_ERR(name)) 765 return PTR_ERR(name); 766 767 mutex_lock_nested(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex, 768 I_MUTEX_PARENT); 769 dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name)); 770 if (IS_ERR(dentry)) { 771 err = PTR_ERR(dentry); 772 goto out_unlock; 773 } 774 775 if (!dentry->d_inode) { 776 err = -ENOENT; 777 goto out_err; 778 } 779 780 inode = dentry->d_inode; 781 if (inode) 782 atomic_inc(&inode->i_count); 783 err = mnt_want_write(ipc_ns->mq_mnt); 784 if (err) 785 goto out_err; 786 err = vfs_unlink(dentry->d_parent->d_inode, dentry); 787 mnt_drop_write(ipc_ns->mq_mnt); 788out_err: 789 dput(dentry); 790 791out_unlock: 792 mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex); 793 putname(name); 794 if (inode) 795 iput(inode); 796 797 return err; 798} 799 800/* Pipelined send and receive functions. 801 * 802 * If a receiver finds no waiting message, then it registers itself in the 803 * list of waiting receivers. A sender checks that list before adding the new 804 * message into the message array. If there is a waiting receiver, then it 805 * bypasses the message array and directly hands the message over to the 806 * receiver. 807 * The receiver accepts the message and returns without grabbing the queue 808 * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers 809 * are necessary. The same algorithm is used for sysv semaphores, see 810 * ipc/sem.c for more details. 811 * 812 * The same algorithm is used for senders. 813 */ 814 815/* pipelined_send() - send a message directly to the task waiting in 816 * sys_mq_timedreceive() (without inserting message into a queue). 817 */ 818static inline void pipelined_send(struct mqueue_inode_info *info, 819 struct msg_msg *message, 820 struct ext_wait_queue *receiver) 821{ 822 receiver->msg = message; 823 list_del(&receiver->list); 824 receiver->state = STATE_PENDING; 825 wake_up_process(receiver->task); 826 smp_wmb(); 827 receiver->state = STATE_READY; 828} 829 830/* pipelined_receive() - if there is task waiting in sys_mq_timedsend() 831 * gets its message and put to the queue (we have one free place for sure). */ 832static inline void pipelined_receive(struct mqueue_inode_info *info) 833{ 834 struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND); 835 836 if (!sender) { 837 /* for poll */ 838 wake_up_interruptible(&info->wait_q); 839 return; 840 } 841 msg_insert(sender->msg, info); 842 list_del(&sender->list); 843 sender->state = STATE_PENDING; 844 wake_up_process(sender->task); 845 smp_wmb(); 846 sender->state = STATE_READY; 847} 848 849SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr, 850 size_t, msg_len, unsigned int, msg_prio, 851 const struct timespec __user *, u_abs_timeout) 852{ 853 struct file *filp; 854 struct inode *inode; 855 struct ext_wait_queue wait; 856 struct ext_wait_queue *receiver; 857 struct msg_msg *msg_ptr; 858 struct mqueue_inode_info *info; 859 struct timespec ts, *p = NULL; 860 long timeout; 861 int ret; 862 863 if (u_abs_timeout) { 864 if (copy_from_user(&ts, u_abs_timeout, 865 sizeof(struct timespec))) 866 return -EFAULT; 867 p = &ts; 868 } 869 870 if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX)) 871 return -EINVAL; 872 873 audit_mq_sendrecv(mqdes, msg_len, msg_prio, p); 874 timeout = prepare_timeout(p); 875 876 ret = -EBADF; 877 filp = fget(mqdes); 878 if (unlikely(!filp)) 879 goto out; 880 881 inode = filp->f_path.dentry->d_inode; 882 if (unlikely(filp->f_op != &mqueue_file_operations)) 883 goto out_fput; 884 info = MQUEUE_I(inode); 885 audit_inode(NULL, filp->f_path.dentry); 886 887 if (unlikely(!(filp->f_mode & FMODE_WRITE))) 888 goto out_fput; 889 890 if (unlikely(msg_len > info->attr.mq_msgsize)) { 891 ret = -EMSGSIZE; 892 goto out_fput; 893 } 894 895 /* First try to allocate memory, before doing anything with 896 * existing queues. */ 897 msg_ptr = load_msg(u_msg_ptr, msg_len); 898 if (IS_ERR(msg_ptr)) { 899 ret = PTR_ERR(msg_ptr); 900 goto out_fput; 901 } 902 msg_ptr->m_ts = msg_len; 903 msg_ptr->m_type = msg_prio; 904 905 spin_lock(&info->lock); 906 907 if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) { 908 if (filp->f_flags & O_NONBLOCK) { 909 spin_unlock(&info->lock); 910 ret = -EAGAIN; 911 } else if (unlikely(timeout < 0)) { 912 spin_unlock(&info->lock); 913 ret = timeout; 914 } else { 915 wait.task = current; 916 wait.msg = (void *) msg_ptr; 917 wait.state = STATE_NONE; 918 ret = wq_sleep(info, SEND, timeout, &wait); 919 } 920 if (ret < 0) 921 free_msg(msg_ptr); 922 } else { 923 receiver = wq_get_first_waiter(info, RECV); 924 if (receiver) { 925 pipelined_send(info, msg_ptr, receiver); 926 } else { 927 /* adds message to the queue */ 928 msg_insert(msg_ptr, info); 929 __do_notify(info); 930 } 931 inode->i_atime = inode->i_mtime = inode->i_ctime = 932 CURRENT_TIME; 933 spin_unlock(&info->lock); 934 ret = 0; 935 } 936out_fput: 937 fput(filp); 938out: 939 return ret; 940} 941 942SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr, 943 size_t, msg_len, unsigned int __user *, u_msg_prio, 944 const struct timespec __user *, u_abs_timeout) 945{ 946 long timeout; 947 ssize_t ret; 948 struct msg_msg *msg_ptr; 949 struct file *filp; 950 struct inode *inode; 951 struct mqueue_inode_info *info; 952 struct ext_wait_queue wait; 953 struct timespec ts, *p = NULL; 954 955 if (u_abs_timeout) { 956 if (copy_from_user(&ts, u_abs_timeout, 957 sizeof(struct timespec))) 958 return -EFAULT; 959 p = &ts; 960 } 961 962 audit_mq_sendrecv(mqdes, msg_len, 0, p); 963 timeout = prepare_timeout(p); 964 965 ret = -EBADF; 966 filp = fget(mqdes); 967 if (unlikely(!filp)) 968 goto out; 969 970 inode = filp->f_path.dentry->d_inode; 971 if (unlikely(filp->f_op != &mqueue_file_operations)) 972 goto out_fput; 973 info = MQUEUE_I(inode); 974 audit_inode(NULL, filp->f_path.dentry); 975 976 if (unlikely(!(filp->f_mode & FMODE_READ))) 977 goto out_fput; 978 979 /* checks if buffer is big enough */ 980 if (unlikely(msg_len < info->attr.mq_msgsize)) { 981 ret = -EMSGSIZE; 982 goto out_fput; 983 } 984 985 spin_lock(&info->lock); 986 if (info->attr.mq_curmsgs == 0) { 987 if (filp->f_flags & O_NONBLOCK) { 988 spin_unlock(&info->lock); 989 ret = -EAGAIN; 990 msg_ptr = NULL; 991 } else if (unlikely(timeout < 0)) { 992 spin_unlock(&info->lock); 993 ret = timeout; 994 msg_ptr = NULL; 995 } else { 996 wait.task = current; 997 wait.state = STATE_NONE; 998 ret = wq_sleep(info, RECV, timeout, &wait); 999 msg_ptr = wait.msg; 1000 } 1001 } else { 1002 msg_ptr = msg_get(info); 1003 1004 inode->i_atime = inode->i_mtime = inode->i_ctime = 1005 CURRENT_TIME; 1006 1007 /* There is now free space in queue. */ 1008 pipelined_receive(info); 1009 spin_unlock(&info->lock); 1010 ret = 0; 1011 } 1012 if (ret == 0) { 1013 ret = msg_ptr->m_ts; 1014 1015 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) || 1016 store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) { 1017 ret = -EFAULT; 1018 } 1019 free_msg(msg_ptr); 1020 } 1021out_fput: 1022 fput(filp); 1023out: 1024 return ret; 1025} 1026 1027/* 1028 * Notes: the case when user wants us to deregister (with NULL as pointer) 1029 * and he isn't currently owner of notification, will be silently discarded. 1030 * It isn't explicitly defined in the POSIX. 1031 */ 1032SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes, 1033 const struct sigevent __user *, u_notification) 1034{ 1035 int ret; 1036 struct file *filp; 1037 struct sock *sock; 1038 struct inode *inode; 1039 struct sigevent notification; 1040 struct mqueue_inode_info *info; 1041 struct sk_buff *nc; 1042 1043 if (u_notification) { 1044 if (copy_from_user(¬ification, u_notification, 1045 sizeof(struct sigevent))) 1046 return -EFAULT; 1047 } 1048 1049 audit_mq_notify(mqdes, u_notification ? ¬ification : NULL); 1050 1051 nc = NULL; 1052 sock = NULL; 1053 if (u_notification != NULL) { 1054 if (unlikely(notification.sigev_notify != SIGEV_NONE && 1055 notification.sigev_notify != SIGEV_SIGNAL && 1056 notification.sigev_notify != SIGEV_THREAD)) 1057 return -EINVAL; 1058 if (notification.sigev_notify == SIGEV_SIGNAL && 1059 !valid_signal(notification.sigev_signo)) { 1060 return -EINVAL; 1061 } 1062 if (notification.sigev_notify == SIGEV_THREAD) { 1063 long timeo; 1064 1065 /* create the notify skb */ 1066 nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL); 1067 ret = -ENOMEM; 1068 if (!nc) 1069 goto out; 1070 ret = -EFAULT; 1071 if (copy_from_user(nc->data, 1072 notification.sigev_value.sival_ptr, 1073 NOTIFY_COOKIE_LEN)) { 1074 goto out; 1075 } 1076 1077 /* TODO: add a header? */ 1078 skb_put(nc, NOTIFY_COOKIE_LEN); 1079 /* and attach it to the socket */ 1080retry: 1081 filp = fget(notification.sigev_signo); 1082 ret = -EBADF; 1083 if (!filp) 1084 goto out; 1085 sock = netlink_getsockbyfilp(filp); 1086 fput(filp); 1087 if (IS_ERR(sock)) { 1088 ret = PTR_ERR(sock); 1089 sock = NULL; 1090 goto out; 1091 } 1092 1093 timeo = MAX_SCHEDULE_TIMEOUT; 1094 ret = netlink_attachskb(sock, nc, &timeo, NULL); 1095 if (ret == 1) 1096 goto retry; 1097 if (ret) { 1098 sock = NULL; 1099 nc = NULL; 1100 goto out; 1101 } 1102 } 1103 } 1104 1105 ret = -EBADF; 1106 filp = fget(mqdes); 1107 if (!filp) 1108 goto out; 1109 1110 inode = filp->f_path.dentry->d_inode; 1111 if (unlikely(filp->f_op != &mqueue_file_operations)) 1112 goto out_fput; 1113 info = MQUEUE_I(inode); 1114 1115 ret = 0; 1116 spin_lock(&info->lock); 1117 if (u_notification == NULL) { 1118 if (info->notify_owner == task_tgid(current)) { 1119 remove_notification(info); 1120 inode->i_atime = inode->i_ctime = CURRENT_TIME; 1121 } 1122 } else if (info->notify_owner != NULL) { 1123 ret = -EBUSY; 1124 } else { 1125 switch (notification.sigev_notify) { 1126 case SIGEV_NONE: 1127 info->notify.sigev_notify = SIGEV_NONE; 1128 break; 1129 case SIGEV_THREAD: 1130 info->notify_sock = sock; 1131 info->notify_cookie = nc; 1132 sock = NULL; 1133 nc = NULL; 1134 info->notify.sigev_notify = SIGEV_THREAD; 1135 break; 1136 case SIGEV_SIGNAL: 1137 info->notify.sigev_signo = notification.sigev_signo; 1138 info->notify.sigev_value = notification.sigev_value; 1139 info->notify.sigev_notify = SIGEV_SIGNAL; 1140 break; 1141 } 1142 1143 info->notify_owner = get_pid(task_tgid(current)); 1144 inode->i_atime = inode->i_ctime = CURRENT_TIME; 1145 } 1146 spin_unlock(&info->lock); 1147out_fput: 1148 fput(filp); 1149out: 1150 if (sock) { 1151 netlink_detachskb(sock, nc); 1152 } else if (nc) { 1153 dev_kfree_skb(nc); 1154 } 1155 return ret; 1156} 1157 1158SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes, 1159 const struct mq_attr __user *, u_mqstat, 1160 struct mq_attr __user *, u_omqstat) 1161{ 1162 int ret; 1163 struct mq_attr mqstat, omqstat; 1164 struct file *filp; 1165 struct inode *inode; 1166 struct mqueue_inode_info *info; 1167 1168 if (u_mqstat != NULL) { 1169 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr))) 1170 return -EFAULT; 1171 if (mqstat.mq_flags & (~O_NONBLOCK)) 1172 return -EINVAL; 1173 } 1174 1175 ret = -EBADF; 1176 filp = fget(mqdes); 1177 if (!filp) 1178 goto out; 1179 1180 inode = filp->f_path.dentry->d_inode; 1181 if (unlikely(filp->f_op != &mqueue_file_operations)) 1182 goto out_fput; 1183 info = MQUEUE_I(inode); 1184 1185 spin_lock(&info->lock); 1186 1187 omqstat = info->attr; 1188 omqstat.mq_flags = filp->f_flags & O_NONBLOCK; 1189 if (u_mqstat) { 1190 audit_mq_getsetattr(mqdes, &mqstat); 1191 spin_lock(&filp->f_lock); 1192 if (mqstat.mq_flags & O_NONBLOCK) 1193 filp->f_flags |= O_NONBLOCK; 1194 else 1195 filp->f_flags &= ~O_NONBLOCK; 1196 spin_unlock(&filp->f_lock); 1197 1198 inode->i_atime = inode->i_ctime = CURRENT_TIME; 1199 } 1200 1201 spin_unlock(&info->lock); 1202 1203 ret = 0; 1204 if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat, 1205 sizeof(struct mq_attr))) 1206 ret = -EFAULT; 1207 1208out_fput: 1209 fput(filp); 1210out: 1211 return ret; 1212} 1213 1214static const struct inode_operations mqueue_dir_inode_operations = { 1215 .lookup = simple_lookup, 1216 .create = mqueue_create, 1217 .unlink = mqueue_unlink, 1218}; 1219 1220static const struct file_operations mqueue_file_operations = { 1221 .flush = mqueue_flush_file, 1222 .poll = mqueue_poll_file, 1223 .read = mqueue_read_file, 1224}; 1225 1226static const struct super_operations mqueue_super_ops = { 1227 .alloc_inode = mqueue_alloc_inode, 1228 .destroy_inode = mqueue_destroy_inode, 1229 .statfs = simple_statfs, 1230 .delete_inode = mqueue_delete_inode, 1231 .drop_inode = generic_delete_inode, 1232}; 1233 1234static struct file_system_type mqueue_fs_type = { 1235 .name = "mqueue", 1236 .get_sb = mqueue_get_sb, 1237 .kill_sb = kill_litter_super, 1238}; 1239 1240int mq_init_ns(struct ipc_namespace *ns) 1241{ 1242 ns->mq_queues_count = 0; 1243 ns->mq_queues_max = DFLT_QUEUESMAX; 1244 ns->mq_msg_max = DFLT_MSGMAX; 1245 ns->mq_msgsize_max = DFLT_MSGSIZEMAX; 1246 1247 ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns); 1248 if (IS_ERR(ns->mq_mnt)) { 1249 int err = PTR_ERR(ns->mq_mnt); 1250 ns->mq_mnt = NULL; 1251 return err; 1252 } 1253 return 0; 1254} 1255 1256void mq_clear_sbinfo(struct ipc_namespace *ns) 1257{ 1258 ns->mq_mnt->mnt_sb->s_fs_info = NULL; 1259} 1260 1261void mq_put_mnt(struct ipc_namespace *ns) 1262{ 1263 mntput(ns->mq_mnt); 1264} 1265 1266static int __init init_mqueue_fs(void) 1267{ 1268 int error; 1269 1270 mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache", 1271 sizeof(struct mqueue_inode_info), 0, 1272 SLAB_HWCACHE_ALIGN, init_once); 1273 if (mqueue_inode_cachep == NULL) 1274 return -ENOMEM; 1275 1276 /* ignore failues - they are not fatal */ 1277 mq_sysctl_table = mq_register_sysctl_table(); 1278 1279 error = register_filesystem(&mqueue_fs_type); 1280 if (error) 1281 goto out_sysctl; 1282 1283 spin_lock_init(&mq_lock); 1284 1285 init_ipc_ns.mq_mnt = kern_mount_data(&mqueue_fs_type, &init_ipc_ns); 1286 if (IS_ERR(init_ipc_ns.mq_mnt)) { 1287 error = PTR_ERR(init_ipc_ns.mq_mnt); 1288 goto out_filesystem; 1289 } 1290 1291 return 0; 1292 1293out_filesystem: 1294 unregister_filesystem(&mqueue_fs_type); 1295out_sysctl: 1296 if (mq_sysctl_table) 1297 unregister_sysctl_table(mq_sysctl_table); 1298 kmem_cache_destroy(mqueue_inode_cachep); 1299 return error; 1300} 1301 1302__initcall(init_mqueue_fs); 1303