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