1 /* 2 * net/sunrpc/rpc_pipe.c 3 * 4 * Userland/kernel interface for rpcauth_gss. 5 * Code shamelessly plagiarized from fs/nfsd/nfsctl.c 6 * and fs/sysfs/inode.c 7 * 8 * Copyright (c) 2002, Trond Myklebust <trond.myklebust@fys.uio.no> 9 * 10 */ 11 #include <linux/module.h> 12 #include <linux/slab.h> 13 #include <linux/string.h> 14 #include <linux/pagemap.h> 15 #include <linux/mount.h> 16 #include <linux/namei.h> 17 #include <linux/fsnotify.h> 18 #include <linux/kernel.h> 19 20 #include <asm/ioctls.h> 21 #include <linux/fs.h> 22 #include <linux/poll.h> 23 #include <linux/wait.h> 24 #include <linux/seq_file.h> 25 26 #include <linux/sunrpc/clnt.h> 27 #include <linux/workqueue.h> 28 #include <linux/sunrpc/rpc_pipe_fs.h> 29 #include <linux/sunrpc/cache.h> 30 31 static struct vfsmount *rpc_mnt __read_mostly; 32 static int rpc_mount_count; 33 34 static struct file_system_type rpc_pipe_fs_type; 35 36 37 static struct kmem_cache *rpc_inode_cachep __read_mostly; 38 39 #define RPC_UPCALL_TIMEOUT (30*HZ) 40 41 static void rpc_purge_list(struct rpc_inode *rpci, struct list_head *head, 42 void (*destroy_msg)(struct rpc_pipe_msg *), int err) 43 { 44 struct rpc_pipe_msg *msg; 45 46 if (list_empty(head)) 47 return; 48 do { 49 msg = list_entry(head->next, struct rpc_pipe_msg, list); 50 list_del_init(&msg->list); 51 msg->errno = err; 52 destroy_msg(msg); 53 } while (!list_empty(head)); 54 wake_up(&rpci->waitq); 55 } 56 57 static void 58 rpc_timeout_upcall_queue(struct work_struct *work) 59 { 60 LIST_HEAD(free_list); 61 struct rpc_inode *rpci = 62 container_of(work, struct rpc_inode, queue_timeout.work); 63 struct inode *inode = &rpci->vfs_inode; 64 void (*destroy_msg)(struct rpc_pipe_msg *); 65 66 spin_lock(&inode->i_lock); 67 if (rpci->ops == NULL) { 68 spin_unlock(&inode->i_lock); 69 return; 70 } 71 destroy_msg = rpci->ops->destroy_msg; 72 if (rpci->nreaders == 0) { 73 list_splice_init(&rpci->pipe, &free_list); 74 rpci->pipelen = 0; 75 } 76 spin_unlock(&inode->i_lock); 77 rpc_purge_list(rpci, &free_list, destroy_msg, -ETIMEDOUT); 78 } 79 80 /** 81 * rpc_queue_upcall - queue an upcall message to userspace 82 * @inode: inode of upcall pipe on which to queue given message 83 * @msg: message to queue 84 * 85 * Call with an @inode created by rpc_mkpipe() to queue an upcall. 86 * A userspace process may then later read the upcall by performing a 87 * read on an open file for this inode. It is up to the caller to 88 * initialize the fields of @msg (other than @msg->list) appropriately. 89 */ 90 int 91 rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg) 92 { 93 struct rpc_inode *rpci = RPC_I(inode); 94 int res = -EPIPE; 95 96 spin_lock(&inode->i_lock); 97 if (rpci->ops == NULL) 98 goto out; 99 if (rpci->nreaders) { 100 list_add_tail(&msg->list, &rpci->pipe); 101 rpci->pipelen += msg->len; 102 res = 0; 103 } else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) { 104 if (list_empty(&rpci->pipe)) 105 queue_delayed_work(rpciod_workqueue, 106 &rpci->queue_timeout, 107 RPC_UPCALL_TIMEOUT); 108 list_add_tail(&msg->list, &rpci->pipe); 109 rpci->pipelen += msg->len; 110 res = 0; 111 } 112 out: 113 spin_unlock(&inode->i_lock); 114 wake_up(&rpci->waitq); 115 return res; 116 } 117 EXPORT_SYMBOL_GPL(rpc_queue_upcall); 118 119 static inline void 120 rpc_inode_setowner(struct inode *inode, void *private) 121 { 122 RPC_I(inode)->private = private; 123 } 124 125 static void 126 rpc_close_pipes(struct inode *inode) 127 { 128 struct rpc_inode *rpci = RPC_I(inode); 129 const struct rpc_pipe_ops *ops; 130 int need_release; 131 132 mutex_lock(&inode->i_mutex); 133 ops = rpci->ops; 134 if (ops != NULL) { 135 LIST_HEAD(free_list); 136 spin_lock(&inode->i_lock); 137 need_release = rpci->nreaders != 0 || rpci->nwriters != 0; 138 rpci->nreaders = 0; 139 list_splice_init(&rpci->in_upcall, &free_list); 140 list_splice_init(&rpci->pipe, &free_list); 141 rpci->pipelen = 0; 142 rpci->ops = NULL; 143 spin_unlock(&inode->i_lock); 144 rpc_purge_list(rpci, &free_list, ops->destroy_msg, -EPIPE); 145 rpci->nwriters = 0; 146 if (need_release && ops->release_pipe) 147 ops->release_pipe(inode); 148 cancel_delayed_work_sync(&rpci->queue_timeout); 149 } 150 rpc_inode_setowner(inode, NULL); 151 mutex_unlock(&inode->i_mutex); 152 } 153 154 static struct inode * 155 rpc_alloc_inode(struct super_block *sb) 156 { 157 struct rpc_inode *rpci; 158 rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL); 159 if (!rpci) 160 return NULL; 161 return &rpci->vfs_inode; 162 } 163 164 static void 165 rpc_i_callback(struct rcu_head *head) 166 { 167 struct inode *inode = container_of(head, struct inode, i_rcu); 168 INIT_LIST_HEAD(&inode->i_dentry); 169 kmem_cache_free(rpc_inode_cachep, RPC_I(inode)); 170 } 171 172 static void 173 rpc_destroy_inode(struct inode *inode) 174 { 175 call_rcu(&inode->i_rcu, rpc_i_callback); 176 } 177 178 static int 179 rpc_pipe_open(struct inode *inode, struct file *filp) 180 { 181 struct rpc_inode *rpci = RPC_I(inode); 182 int first_open; 183 int res = -ENXIO; 184 185 mutex_lock(&inode->i_mutex); 186 if (rpci->ops == NULL) 187 goto out; 188 first_open = rpci->nreaders == 0 && rpci->nwriters == 0; 189 if (first_open && rpci->ops->open_pipe) { 190 res = rpci->ops->open_pipe(inode); 191 if (res) 192 goto out; 193 } 194 if (filp->f_mode & FMODE_READ) 195 rpci->nreaders++; 196 if (filp->f_mode & FMODE_WRITE) 197 rpci->nwriters++; 198 res = 0; 199 out: 200 mutex_unlock(&inode->i_mutex); 201 return res; 202 } 203 204 static int 205 rpc_pipe_release(struct inode *inode, struct file *filp) 206 { 207 struct rpc_inode *rpci = RPC_I(inode); 208 struct rpc_pipe_msg *msg; 209 int last_close; 210 211 mutex_lock(&inode->i_mutex); 212 if (rpci->ops == NULL) 213 goto out; 214 msg = filp->private_data; 215 if (msg != NULL) { 216 spin_lock(&inode->i_lock); 217 msg->errno = -EAGAIN; 218 list_del_init(&msg->list); 219 spin_unlock(&inode->i_lock); 220 rpci->ops->destroy_msg(msg); 221 } 222 if (filp->f_mode & FMODE_WRITE) 223 rpci->nwriters --; 224 if (filp->f_mode & FMODE_READ) { 225 rpci->nreaders --; 226 if (rpci->nreaders == 0) { 227 LIST_HEAD(free_list); 228 spin_lock(&inode->i_lock); 229 list_splice_init(&rpci->pipe, &free_list); 230 rpci->pipelen = 0; 231 spin_unlock(&inode->i_lock); 232 rpc_purge_list(rpci, &free_list, 233 rpci->ops->destroy_msg, -EAGAIN); 234 } 235 } 236 last_close = rpci->nwriters == 0 && rpci->nreaders == 0; 237 if (last_close && rpci->ops->release_pipe) 238 rpci->ops->release_pipe(inode); 239 out: 240 mutex_unlock(&inode->i_mutex); 241 return 0; 242 } 243 244 static ssize_t 245 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset) 246 { 247 struct inode *inode = filp->f_path.dentry->d_inode; 248 struct rpc_inode *rpci = RPC_I(inode); 249 struct rpc_pipe_msg *msg; 250 int res = 0; 251 252 mutex_lock(&inode->i_mutex); 253 if (rpci->ops == NULL) { 254 res = -EPIPE; 255 goto out_unlock; 256 } 257 msg = filp->private_data; 258 if (msg == NULL) { 259 spin_lock(&inode->i_lock); 260 if (!list_empty(&rpci->pipe)) { 261 msg = list_entry(rpci->pipe.next, 262 struct rpc_pipe_msg, 263 list); 264 list_move(&msg->list, &rpci->in_upcall); 265 rpci->pipelen -= msg->len; 266 filp->private_data = msg; 267 msg->copied = 0; 268 } 269 spin_unlock(&inode->i_lock); 270 if (msg == NULL) 271 goto out_unlock; 272 } 273 /* NOTE: it is up to the callback to update msg->copied */ 274 res = rpci->ops->upcall(filp, msg, buf, len); 275 if (res < 0 || msg->len == msg->copied) { 276 filp->private_data = NULL; 277 spin_lock(&inode->i_lock); 278 list_del_init(&msg->list); 279 spin_unlock(&inode->i_lock); 280 rpci->ops->destroy_msg(msg); 281 } 282 out_unlock: 283 mutex_unlock(&inode->i_mutex); 284 return res; 285 } 286 287 static ssize_t 288 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset) 289 { 290 struct inode *inode = filp->f_path.dentry->d_inode; 291 struct rpc_inode *rpci = RPC_I(inode); 292 int res; 293 294 mutex_lock(&inode->i_mutex); 295 res = -EPIPE; 296 if (rpci->ops != NULL) 297 res = rpci->ops->downcall(filp, buf, len); 298 mutex_unlock(&inode->i_mutex); 299 return res; 300 } 301 302 static unsigned int 303 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait) 304 { 305 struct rpc_inode *rpci; 306 unsigned int mask = 0; 307 308 rpci = RPC_I(filp->f_path.dentry->d_inode); 309 poll_wait(filp, &rpci->waitq, wait); 310 311 mask = POLLOUT | POLLWRNORM; 312 if (rpci->ops == NULL) 313 mask |= POLLERR | POLLHUP; 314 if (filp->private_data || !list_empty(&rpci->pipe)) 315 mask |= POLLIN | POLLRDNORM; 316 return mask; 317 } 318 319 static long 320 rpc_pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 321 { 322 struct inode *inode = filp->f_path.dentry->d_inode; 323 struct rpc_inode *rpci = RPC_I(inode); 324 int len; 325 326 switch (cmd) { 327 case FIONREAD: 328 spin_lock(&inode->i_lock); 329 if (rpci->ops == NULL) { 330 spin_unlock(&inode->i_lock); 331 return -EPIPE; 332 } 333 len = rpci->pipelen; 334 if (filp->private_data) { 335 struct rpc_pipe_msg *msg; 336 msg = filp->private_data; 337 len += msg->len - msg->copied; 338 } 339 spin_unlock(&inode->i_lock); 340 return put_user(len, (int __user *)arg); 341 default: 342 return -EINVAL; 343 } 344 } 345 346 static const struct file_operations rpc_pipe_fops = { 347 .owner = THIS_MODULE, 348 .llseek = no_llseek, 349 .read = rpc_pipe_read, 350 .write = rpc_pipe_write, 351 .poll = rpc_pipe_poll, 352 .unlocked_ioctl = rpc_pipe_ioctl, 353 .open = rpc_pipe_open, 354 .release = rpc_pipe_release, 355 }; 356 357 static int 358 rpc_show_info(struct seq_file *m, void *v) 359 { 360 struct rpc_clnt *clnt = m->private; 361 362 seq_printf(m, "RPC server: %s\n", clnt->cl_server); 363 seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname, 364 clnt->cl_prog, clnt->cl_vers); 365 seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR)); 366 seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO)); 367 seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT)); 368 return 0; 369 } 370 371 static int 372 rpc_info_open(struct inode *inode, struct file *file) 373 { 374 struct rpc_clnt *clnt = NULL; 375 int ret = single_open(file, rpc_show_info, NULL); 376 377 if (!ret) { 378 struct seq_file *m = file->private_data; 379 380 spin_lock(&file->f_path.dentry->d_lock); 381 if (!d_unhashed(file->f_path.dentry)) 382 clnt = RPC_I(inode)->private; 383 if (clnt != NULL && atomic_inc_not_zero(&clnt->cl_count)) { 384 spin_unlock(&file->f_path.dentry->d_lock); 385 m->private = clnt; 386 } else { 387 spin_unlock(&file->f_path.dentry->d_lock); 388 single_release(inode, file); 389 ret = -EINVAL; 390 } 391 } 392 return ret; 393 } 394 395 static int 396 rpc_info_release(struct inode *inode, struct file *file) 397 { 398 struct seq_file *m = file->private_data; 399 struct rpc_clnt *clnt = (struct rpc_clnt *)m->private; 400 401 if (clnt) 402 rpc_release_client(clnt); 403 return single_release(inode, file); 404 } 405 406 static const struct file_operations rpc_info_operations = { 407 .owner = THIS_MODULE, 408 .open = rpc_info_open, 409 .read = seq_read, 410 .llseek = seq_lseek, 411 .release = rpc_info_release, 412 }; 413 414 415 /* 416 * Description of fs contents. 417 */ 418 struct rpc_filelist { 419 const char *name; 420 const struct file_operations *i_fop; 421 umode_t mode; 422 }; 423 424 struct vfsmount *rpc_get_mount(void) 425 { 426 int err; 427 428 err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mnt, &rpc_mount_count); 429 if (err != 0) 430 return ERR_PTR(err); 431 return rpc_mnt; 432 } 433 EXPORT_SYMBOL_GPL(rpc_get_mount); 434 435 void rpc_put_mount(void) 436 { 437 simple_release_fs(&rpc_mnt, &rpc_mount_count); 438 } 439 EXPORT_SYMBOL_GPL(rpc_put_mount); 440 441 static int rpc_delete_dentry(const struct dentry *dentry) 442 { 443 return 1; 444 } 445 446 static const struct dentry_operations rpc_dentry_operations = { 447 .d_delete = rpc_delete_dentry, 448 }; 449 450 static struct inode * 451 rpc_get_inode(struct super_block *sb, umode_t mode) 452 { 453 struct inode *inode = new_inode(sb); 454 if (!inode) 455 return NULL; 456 inode->i_ino = get_next_ino(); 457 inode->i_mode = mode; 458 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; 459 switch(mode & S_IFMT) { 460 case S_IFDIR: 461 inode->i_fop = &simple_dir_operations; 462 inode->i_op = &simple_dir_inode_operations; 463 inc_nlink(inode); 464 default: 465 break; 466 } 467 return inode; 468 } 469 470 static int __rpc_create_common(struct inode *dir, struct dentry *dentry, 471 umode_t mode, 472 const struct file_operations *i_fop, 473 void *private) 474 { 475 struct inode *inode; 476 477 d_drop(dentry); 478 inode = rpc_get_inode(dir->i_sb, mode); 479 if (!inode) 480 goto out_err; 481 inode->i_ino = iunique(dir->i_sb, 100); 482 if (i_fop) 483 inode->i_fop = i_fop; 484 if (private) 485 rpc_inode_setowner(inode, private); 486 d_add(dentry, inode); 487 return 0; 488 out_err: 489 printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n", 490 __FILE__, __func__, dentry->d_name.name); 491 dput(dentry); 492 return -ENOMEM; 493 } 494 495 static int __rpc_create(struct inode *dir, struct dentry *dentry, 496 umode_t mode, 497 const struct file_operations *i_fop, 498 void *private) 499 { 500 int err; 501 502 err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private); 503 if (err) 504 return err; 505 fsnotify_create(dir, dentry); 506 return 0; 507 } 508 509 static int __rpc_mkdir(struct inode *dir, struct dentry *dentry, 510 umode_t mode, 511 const struct file_operations *i_fop, 512 void *private) 513 { 514 int err; 515 516 err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private); 517 if (err) 518 return err; 519 inc_nlink(dir); 520 fsnotify_mkdir(dir, dentry); 521 return 0; 522 } 523 524 static int __rpc_mkpipe(struct inode *dir, struct dentry *dentry, 525 umode_t mode, 526 const struct file_operations *i_fop, 527 void *private, 528 const struct rpc_pipe_ops *ops, 529 int flags) 530 { 531 struct rpc_inode *rpci; 532 int err; 533 534 err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private); 535 if (err) 536 return err; 537 rpci = RPC_I(dentry->d_inode); 538 rpci->nkern_readwriters = 1; 539 rpci->private = private; 540 rpci->flags = flags; 541 rpci->ops = ops; 542 fsnotify_create(dir, dentry); 543 return 0; 544 } 545 546 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry) 547 { 548 int ret; 549 550 dget(dentry); 551 ret = simple_rmdir(dir, dentry); 552 d_delete(dentry); 553 dput(dentry); 554 return ret; 555 } 556 557 static int __rpc_unlink(struct inode *dir, struct dentry *dentry) 558 { 559 int ret; 560 561 dget(dentry); 562 ret = simple_unlink(dir, dentry); 563 d_delete(dentry); 564 dput(dentry); 565 return ret; 566 } 567 568 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry) 569 { 570 struct inode *inode = dentry->d_inode; 571 struct rpc_inode *rpci = RPC_I(inode); 572 573 rpci->nkern_readwriters--; 574 if (rpci->nkern_readwriters != 0) 575 return 0; 576 rpc_close_pipes(inode); 577 return __rpc_unlink(dir, dentry); 578 } 579 580 static struct dentry *__rpc_lookup_create(struct dentry *parent, 581 struct qstr *name) 582 { 583 struct dentry *dentry; 584 585 dentry = d_lookup(parent, name); 586 if (!dentry) { 587 dentry = d_alloc(parent, name); 588 if (!dentry) { 589 dentry = ERR_PTR(-ENOMEM); 590 goto out_err; 591 } 592 } 593 if (!dentry->d_inode) 594 d_set_d_op(dentry, &rpc_dentry_operations); 595 out_err: 596 return dentry; 597 } 598 599 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent, 600 struct qstr *name) 601 { 602 struct dentry *dentry; 603 604 dentry = __rpc_lookup_create(parent, name); 605 if (IS_ERR(dentry)) 606 return dentry; 607 if (dentry->d_inode == NULL) 608 return dentry; 609 dput(dentry); 610 return ERR_PTR(-EEXIST); 611 } 612 613 /* 614 * FIXME: This probably has races. 615 */ 616 static void __rpc_depopulate(struct dentry *parent, 617 const struct rpc_filelist *files, 618 int start, int eof) 619 { 620 struct inode *dir = parent->d_inode; 621 struct dentry *dentry; 622 struct qstr name; 623 int i; 624 625 for (i = start; i < eof; i++) { 626 name.name = files[i].name; 627 name.len = strlen(files[i].name); 628 name.hash = full_name_hash(name.name, name.len); 629 dentry = d_lookup(parent, &name); 630 631 if (dentry == NULL) 632 continue; 633 if (dentry->d_inode == NULL) 634 goto next; 635 switch (dentry->d_inode->i_mode & S_IFMT) { 636 default: 637 BUG(); 638 case S_IFREG: 639 __rpc_unlink(dir, dentry); 640 break; 641 case S_IFDIR: 642 __rpc_rmdir(dir, dentry); 643 } 644 next: 645 dput(dentry); 646 } 647 } 648 649 static void rpc_depopulate(struct dentry *parent, 650 const struct rpc_filelist *files, 651 int start, int eof) 652 { 653 struct inode *dir = parent->d_inode; 654 655 mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD); 656 __rpc_depopulate(parent, files, start, eof); 657 mutex_unlock(&dir->i_mutex); 658 } 659 660 static int rpc_populate(struct dentry *parent, 661 const struct rpc_filelist *files, 662 int start, int eof, 663 void *private) 664 { 665 struct inode *dir = parent->d_inode; 666 struct dentry *dentry; 667 int i, err; 668 669 mutex_lock(&dir->i_mutex); 670 for (i = start; i < eof; i++) { 671 struct qstr q; 672 673 q.name = files[i].name; 674 q.len = strlen(files[i].name); 675 q.hash = full_name_hash(q.name, q.len); 676 dentry = __rpc_lookup_create_exclusive(parent, &q); 677 err = PTR_ERR(dentry); 678 if (IS_ERR(dentry)) 679 goto out_bad; 680 switch (files[i].mode & S_IFMT) { 681 default: 682 BUG(); 683 case S_IFREG: 684 err = __rpc_create(dir, dentry, 685 files[i].mode, 686 files[i].i_fop, 687 private); 688 break; 689 case S_IFDIR: 690 err = __rpc_mkdir(dir, dentry, 691 files[i].mode, 692 NULL, 693 private); 694 } 695 if (err != 0) 696 goto out_bad; 697 } 698 mutex_unlock(&dir->i_mutex); 699 return 0; 700 out_bad: 701 __rpc_depopulate(parent, files, start, eof); 702 mutex_unlock(&dir->i_mutex); 703 printk(KERN_WARNING "%s: %s failed to populate directory %s\n", 704 __FILE__, __func__, parent->d_name.name); 705 return err; 706 } 707 708 static struct dentry *rpc_mkdir_populate(struct dentry *parent, 709 struct qstr *name, umode_t mode, void *private, 710 int (*populate)(struct dentry *, void *), void *args_populate) 711 { 712 struct dentry *dentry; 713 struct inode *dir = parent->d_inode; 714 int error; 715 716 mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT); 717 dentry = __rpc_lookup_create_exclusive(parent, name); 718 if (IS_ERR(dentry)) 719 goto out; 720 error = __rpc_mkdir(dir, dentry, mode, NULL, private); 721 if (error != 0) 722 goto out_err; 723 if (populate != NULL) { 724 error = populate(dentry, args_populate); 725 if (error) 726 goto err_rmdir; 727 } 728 out: 729 mutex_unlock(&dir->i_mutex); 730 return dentry; 731 err_rmdir: 732 __rpc_rmdir(dir, dentry); 733 out_err: 734 dentry = ERR_PTR(error); 735 goto out; 736 } 737 738 static int rpc_rmdir_depopulate(struct dentry *dentry, 739 void (*depopulate)(struct dentry *)) 740 { 741 struct dentry *parent; 742 struct inode *dir; 743 int error; 744 745 parent = dget_parent(dentry); 746 dir = parent->d_inode; 747 mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT); 748 if (depopulate != NULL) 749 depopulate(dentry); 750 error = __rpc_rmdir(dir, dentry); 751 mutex_unlock(&dir->i_mutex); 752 dput(parent); 753 return error; 754 } 755 756 /** 757 * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication 758 * @parent: dentry of directory to create new "pipe" in 759 * @name: name of pipe 760 * @private: private data to associate with the pipe, for the caller's use 761 * @ops: operations defining the behavior of the pipe: upcall, downcall, 762 * release_pipe, open_pipe, and destroy_msg. 763 * @flags: rpc_inode flags 764 * 765 * Data is made available for userspace to read by calls to 766 * rpc_queue_upcall(). The actual reads will result in calls to 767 * @ops->upcall, which will be called with the file pointer, 768 * message, and userspace buffer to copy to. 769 * 770 * Writes can come at any time, and do not necessarily have to be 771 * responses to upcalls. They will result in calls to @msg->downcall. 772 * 773 * The @private argument passed here will be available to all these methods 774 * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private. 775 */ 776 struct dentry *rpc_mkpipe(struct dentry *parent, const char *name, 777 void *private, const struct rpc_pipe_ops *ops, 778 int flags) 779 { 780 struct dentry *dentry; 781 struct inode *dir = parent->d_inode; 782 umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR; 783 struct qstr q; 784 int err; 785 786 if (ops->upcall == NULL) 787 umode &= ~S_IRUGO; 788 if (ops->downcall == NULL) 789 umode &= ~S_IWUGO; 790 791 q.name = name; 792 q.len = strlen(name); 793 q.hash = full_name_hash(q.name, q.len), 794 795 mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT); 796 dentry = __rpc_lookup_create(parent, &q); 797 if (IS_ERR(dentry)) 798 goto out; 799 if (dentry->d_inode) { 800 struct rpc_inode *rpci = RPC_I(dentry->d_inode); 801 if (rpci->private != private || 802 rpci->ops != ops || 803 rpci->flags != flags) { 804 dput (dentry); 805 err = -EBUSY; 806 goto out_err; 807 } 808 rpci->nkern_readwriters++; 809 goto out; 810 } 811 812 err = __rpc_mkpipe(dir, dentry, umode, &rpc_pipe_fops, 813 private, ops, flags); 814 if (err) 815 goto out_err; 816 out: 817 mutex_unlock(&dir->i_mutex); 818 return dentry; 819 out_err: 820 dentry = ERR_PTR(err); 821 printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n", 822 __FILE__, __func__, parent->d_name.name, name, 823 err); 824 goto out; 825 } 826 EXPORT_SYMBOL_GPL(rpc_mkpipe); 827 828 /** 829 * rpc_unlink - remove a pipe 830 * @dentry: dentry for the pipe, as returned from rpc_mkpipe 831 * 832 * After this call, lookups will no longer find the pipe, and any 833 * attempts to read or write using preexisting opens of the pipe will 834 * return -EPIPE. 835 */ 836 int 837 rpc_unlink(struct dentry *dentry) 838 { 839 struct dentry *parent; 840 struct inode *dir; 841 int error = 0; 842 843 parent = dget_parent(dentry); 844 dir = parent->d_inode; 845 mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT); 846 error = __rpc_rmpipe(dir, dentry); 847 mutex_unlock(&dir->i_mutex); 848 dput(parent); 849 return error; 850 } 851 EXPORT_SYMBOL_GPL(rpc_unlink); 852 853 enum { 854 RPCAUTH_info, 855 RPCAUTH_EOF 856 }; 857 858 static const struct rpc_filelist authfiles[] = { 859 [RPCAUTH_info] = { 860 .name = "info", 861 .i_fop = &rpc_info_operations, 862 .mode = S_IFREG | S_IRUSR, 863 }, 864 }; 865 866 static int rpc_clntdir_populate(struct dentry *dentry, void *private) 867 { 868 return rpc_populate(dentry, 869 authfiles, RPCAUTH_info, RPCAUTH_EOF, 870 private); 871 } 872 873 static void rpc_clntdir_depopulate(struct dentry *dentry) 874 { 875 rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF); 876 } 877 878 /** 879 * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs 880 * @dentry: dentry from the rpc_pipefs root to the new directory 881 * @name: &struct qstr for the name 882 * @rpc_client: rpc client to associate with this directory 883 * 884 * This creates a directory at the given @path associated with 885 * @rpc_clnt, which will contain a file named "info" with some basic 886 * information about the client, together with any "pipes" that may 887 * later be created using rpc_mkpipe(). 888 */ 889 struct dentry *rpc_create_client_dir(struct dentry *dentry, 890 struct qstr *name, 891 struct rpc_clnt *rpc_client) 892 { 893 return rpc_mkdir_populate(dentry, name, S_IRUGO | S_IXUGO, NULL, 894 rpc_clntdir_populate, rpc_client); 895 } 896 897 /** 898 * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir() 899 * @dentry: directory to remove 900 */ 901 int rpc_remove_client_dir(struct dentry *dentry) 902 { 903 return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate); 904 } 905 906 static const struct rpc_filelist cache_pipefs_files[3] = { 907 [0] = { 908 .name = "channel", 909 .i_fop = &cache_file_operations_pipefs, 910 .mode = S_IFREG|S_IRUSR|S_IWUSR, 911 }, 912 [1] = { 913 .name = "content", 914 .i_fop = &content_file_operations_pipefs, 915 .mode = S_IFREG|S_IRUSR, 916 }, 917 [2] = { 918 .name = "flush", 919 .i_fop = &cache_flush_operations_pipefs, 920 .mode = S_IFREG|S_IRUSR|S_IWUSR, 921 }, 922 }; 923 924 static int rpc_cachedir_populate(struct dentry *dentry, void *private) 925 { 926 return rpc_populate(dentry, 927 cache_pipefs_files, 0, 3, 928 private); 929 } 930 931 static void rpc_cachedir_depopulate(struct dentry *dentry) 932 { 933 rpc_depopulate(dentry, cache_pipefs_files, 0, 3); 934 } 935 936 struct dentry *rpc_create_cache_dir(struct dentry *parent, struct qstr *name, 937 mode_t umode, struct cache_detail *cd) 938 { 939 return rpc_mkdir_populate(parent, name, umode, NULL, 940 rpc_cachedir_populate, cd); 941 } 942 943 void rpc_remove_cache_dir(struct dentry *dentry) 944 { 945 rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate); 946 } 947 948 /* 949 * populate the filesystem 950 */ 951 static const struct super_operations s_ops = { 952 .alloc_inode = rpc_alloc_inode, 953 .destroy_inode = rpc_destroy_inode, 954 .statfs = simple_statfs, 955 }; 956 957 #define RPCAUTH_GSSMAGIC 0x67596969 958 959 /* 960 * We have a single directory with 1 node in it. 961 */ 962 enum { 963 RPCAUTH_lockd, 964 RPCAUTH_mount, 965 RPCAUTH_nfs, 966 RPCAUTH_portmap, 967 RPCAUTH_statd, 968 RPCAUTH_nfsd4_cb, 969 RPCAUTH_cache, 970 RPCAUTH_RootEOF 971 }; 972 973 static const struct rpc_filelist files[] = { 974 [RPCAUTH_lockd] = { 975 .name = "lockd", 976 .mode = S_IFDIR | S_IRUGO | S_IXUGO, 977 }, 978 [RPCAUTH_mount] = { 979 .name = "mount", 980 .mode = S_IFDIR | S_IRUGO | S_IXUGO, 981 }, 982 [RPCAUTH_nfs] = { 983 .name = "nfs", 984 .mode = S_IFDIR | S_IRUGO | S_IXUGO, 985 }, 986 [RPCAUTH_portmap] = { 987 .name = "portmap", 988 .mode = S_IFDIR | S_IRUGO | S_IXUGO, 989 }, 990 [RPCAUTH_statd] = { 991 .name = "statd", 992 .mode = S_IFDIR | S_IRUGO | S_IXUGO, 993 }, 994 [RPCAUTH_nfsd4_cb] = { 995 .name = "nfsd4_cb", 996 .mode = S_IFDIR | S_IRUGO | S_IXUGO, 997 }, 998 [RPCAUTH_cache] = { 999 .name = "cache", 1000 .mode = S_IFDIR | S_IRUGO | S_IXUGO, 1001 }, 1002 }; 1003 1004 static int 1005 rpc_fill_super(struct super_block *sb, void *data, int silent) 1006 { 1007 struct inode *inode; 1008 struct dentry *root; 1009 1010 sb->s_blocksize = PAGE_CACHE_SIZE; 1011 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 1012 sb->s_magic = RPCAUTH_GSSMAGIC; 1013 sb->s_op = &s_ops; 1014 sb->s_time_gran = 1; 1015 1016 inode = rpc_get_inode(sb, S_IFDIR | 0755); 1017 if (!inode) 1018 return -ENOMEM; 1019 sb->s_root = root = d_alloc_root(inode); 1020 if (!root) { 1021 iput(inode); 1022 return -ENOMEM; 1023 } 1024 if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL)) 1025 return -ENOMEM; 1026 return 0; 1027 } 1028 1029 static struct dentry * 1030 rpc_mount(struct file_system_type *fs_type, 1031 int flags, const char *dev_name, void *data) 1032 { 1033 return mount_single(fs_type, flags, data, rpc_fill_super); 1034 } 1035 1036 static struct file_system_type rpc_pipe_fs_type = { 1037 .owner = THIS_MODULE, 1038 .name = "rpc_pipefs", 1039 .mount = rpc_mount, 1040 .kill_sb = kill_litter_super, 1041 }; 1042 1043 static void 1044 init_once(void *foo) 1045 { 1046 struct rpc_inode *rpci = (struct rpc_inode *) foo; 1047 1048 inode_init_once(&rpci->vfs_inode); 1049 rpci->private = NULL; 1050 rpci->nreaders = 0; 1051 rpci->nwriters = 0; 1052 INIT_LIST_HEAD(&rpci->in_upcall); 1053 INIT_LIST_HEAD(&rpci->in_downcall); 1054 INIT_LIST_HEAD(&rpci->pipe); 1055 rpci->pipelen = 0; 1056 init_waitqueue_head(&rpci->waitq); 1057 INIT_DELAYED_WORK(&rpci->queue_timeout, 1058 rpc_timeout_upcall_queue); 1059 rpci->ops = NULL; 1060 } 1061 1062 int register_rpc_pipefs(void) 1063 { 1064 int err; 1065 1066 rpc_inode_cachep = kmem_cache_create("rpc_inode_cache", 1067 sizeof(struct rpc_inode), 1068 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT| 1069 SLAB_MEM_SPREAD), 1070 init_once); 1071 if (!rpc_inode_cachep) 1072 return -ENOMEM; 1073 err = register_filesystem(&rpc_pipe_fs_type); 1074 if (err) { 1075 kmem_cache_destroy(rpc_inode_cachep); 1076 return err; 1077 } 1078 1079 return 0; 1080 } 1081 1082 void unregister_rpc_pipefs(void) 1083 { 1084 kmem_cache_destroy(rpc_inode_cachep); 1085 unregister_filesystem(&rpc_pipe_fs_type); 1086 } 1087