1 /* 2 * net/sunrpc/cache.c 3 * 4 * Generic code for various authentication-related caches 5 * used by sunrpc clients and servers. 6 * 7 * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au> 8 * 9 * Released under terms in GPL version 2. See COPYING. 10 * 11 */ 12 13 #include <linux/types.h> 14 #include <linux/fs.h> 15 #include <linux/file.h> 16 #include <linux/slab.h> 17 #include <linux/signal.h> 18 #include <linux/sched.h> 19 #include <linux/kmod.h> 20 #include <linux/list.h> 21 #include <linux/module.h> 22 #include <linux/ctype.h> 23 #include <asm/uaccess.h> 24 #include <linux/poll.h> 25 #include <linux/seq_file.h> 26 #include <linux/proc_fs.h> 27 #include <linux/net.h> 28 #include <linux/workqueue.h> 29 #include <linux/mutex.h> 30 #include <asm/ioctls.h> 31 #include <linux/sunrpc/types.h> 32 #include <linux/sunrpc/cache.h> 33 #include <linux/sunrpc/stats.h> 34 35 #define RPCDBG_FACILITY RPCDBG_CACHE 36 37 static void cache_defer_req(struct cache_req *req, struct cache_head *item); 38 static void cache_revisit_request(struct cache_head *item); 39 40 static void cache_init(struct cache_head *h) 41 { 42 time_t now = get_seconds(); 43 h->next = NULL; 44 h->flags = 0; 45 kref_init(&h->ref); 46 h->expiry_time = now + CACHE_NEW_EXPIRY; 47 h->last_refresh = now; 48 } 49 50 struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail, 51 struct cache_head *key, int hash) 52 { 53 struct cache_head **head, **hp; 54 struct cache_head *new = NULL; 55 56 head = &detail->hash_table[hash]; 57 58 read_lock(&detail->hash_lock); 59 60 for (hp=head; *hp != NULL ; hp = &(*hp)->next) { 61 struct cache_head *tmp = *hp; 62 if (detail->match(tmp, key)) { 63 cache_get(tmp); 64 read_unlock(&detail->hash_lock); 65 return tmp; 66 } 67 } 68 read_unlock(&detail->hash_lock); 69 /* Didn't find anything, insert an empty entry */ 70 71 new = detail->alloc(); 72 if (!new) 73 return NULL; 74 /* must fully initialise 'new', else 75 * we might get lose if we need to 76 * cache_put it soon. 77 */ 78 cache_init(new); 79 detail->init(new, key); 80 81 write_lock(&detail->hash_lock); 82 83 /* check if entry appeared while we slept */ 84 for (hp=head; *hp != NULL ; hp = &(*hp)->next) { 85 struct cache_head *tmp = *hp; 86 if (detail->match(tmp, key)) { 87 cache_get(tmp); 88 write_unlock(&detail->hash_lock); 89 cache_put(new, detail); 90 return tmp; 91 } 92 } 93 new->next = *head; 94 *head = new; 95 detail->entries++; 96 cache_get(new); 97 write_unlock(&detail->hash_lock); 98 99 return new; 100 } 101 EXPORT_SYMBOL(sunrpc_cache_lookup); 102 103 104 static void queue_loose(struct cache_detail *detail, struct cache_head *ch); 105 106 static int cache_fresh_locked(struct cache_head *head, time_t expiry) 107 { 108 head->expiry_time = expiry; 109 head->last_refresh = get_seconds(); 110 return !test_and_set_bit(CACHE_VALID, &head->flags); 111 } 112 113 static void cache_fresh_unlocked(struct cache_head *head, 114 struct cache_detail *detail, int new) 115 { 116 if (new) 117 cache_revisit_request(head); 118 if (test_and_clear_bit(CACHE_PENDING, &head->flags)) { 119 cache_revisit_request(head); 120 queue_loose(detail, head); 121 } 122 } 123 124 struct cache_head *sunrpc_cache_update(struct cache_detail *detail, 125 struct cache_head *new, struct cache_head *old, int hash) 126 { 127 /* The 'old' entry is to be replaced by 'new'. 128 * If 'old' is not VALID, we update it directly, 129 * otherwise we need to replace it 130 */ 131 struct cache_head **head; 132 struct cache_head *tmp; 133 int is_new; 134 135 if (!test_bit(CACHE_VALID, &old->flags)) { 136 write_lock(&detail->hash_lock); 137 if (!test_bit(CACHE_VALID, &old->flags)) { 138 if (test_bit(CACHE_NEGATIVE, &new->flags)) 139 set_bit(CACHE_NEGATIVE, &old->flags); 140 else 141 detail->update(old, new); 142 is_new = cache_fresh_locked(old, new->expiry_time); 143 write_unlock(&detail->hash_lock); 144 cache_fresh_unlocked(old, detail, is_new); 145 return old; 146 } 147 write_unlock(&detail->hash_lock); 148 } 149 /* We need to insert a new entry */ 150 tmp = detail->alloc(); 151 if (!tmp) { 152 cache_put(old, detail); 153 return NULL; 154 } 155 cache_init(tmp); 156 detail->init(tmp, old); 157 head = &detail->hash_table[hash]; 158 159 write_lock(&detail->hash_lock); 160 if (test_bit(CACHE_NEGATIVE, &new->flags)) 161 set_bit(CACHE_NEGATIVE, &tmp->flags); 162 else 163 detail->update(tmp, new); 164 tmp->next = *head; 165 *head = tmp; 166 detail->entries++; 167 cache_get(tmp); 168 is_new = cache_fresh_locked(tmp, new->expiry_time); 169 cache_fresh_locked(old, 0); 170 write_unlock(&detail->hash_lock); 171 cache_fresh_unlocked(tmp, detail, is_new); 172 cache_fresh_unlocked(old, detail, 0); 173 cache_put(old, detail); 174 return tmp; 175 } 176 EXPORT_SYMBOL(sunrpc_cache_update); 177 178 static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h); 179 /* 180 * This is the generic cache management routine for all 181 * the authentication caches. 182 * It checks the currency of a cache item and will (later) 183 * initiate an upcall to fill it if needed. 184 * 185 * 186 * Returns 0 if the cache_head can be used, or cache_puts it and returns 187 * -EAGAIN if upcall is pending, 188 * -ENOENT if cache entry was negative 189 */ 190 int cache_check(struct cache_detail *detail, 191 struct cache_head *h, struct cache_req *rqstp) 192 { 193 int rv; 194 long refresh_age, age; 195 196 /* First decide return status as best we can */ 197 if (!test_bit(CACHE_VALID, &h->flags) || 198 h->expiry_time < get_seconds()) 199 rv = -EAGAIN; 200 else if (detail->flush_time > h->last_refresh) 201 rv = -EAGAIN; 202 else { 203 /* entry is valid */ 204 if (test_bit(CACHE_NEGATIVE, &h->flags)) 205 rv = -ENOENT; 206 else rv = 0; 207 } 208 209 /* now see if we want to start an upcall */ 210 refresh_age = (h->expiry_time - h->last_refresh); 211 age = get_seconds() - h->last_refresh; 212 213 if (rqstp == NULL) { 214 if (rv == -EAGAIN) 215 rv = -ENOENT; 216 } else if (rv == -EAGAIN || age > refresh_age/2) { 217 dprintk("Want update, refage=%ld, age=%ld\n", refresh_age, age); 218 if (!test_and_set_bit(CACHE_PENDING, &h->flags)) { 219 switch (cache_make_upcall(detail, h)) { 220 case -EINVAL: 221 clear_bit(CACHE_PENDING, &h->flags); 222 if (rv == -EAGAIN) { 223 set_bit(CACHE_NEGATIVE, &h->flags); 224 cache_fresh_unlocked(h, detail, 225 cache_fresh_locked(h, get_seconds()+CACHE_NEW_EXPIRY)); 226 rv = -ENOENT; 227 } 228 break; 229 230 case -EAGAIN: 231 clear_bit(CACHE_PENDING, &h->flags); 232 cache_revisit_request(h); 233 break; 234 } 235 } 236 } 237 238 if (rv == -EAGAIN) 239 cache_defer_req(rqstp, h); 240 241 if (rv) 242 cache_put(h, detail); 243 return rv; 244 } 245 246 /* 247 * caches need to be periodically cleaned. 248 * For this we maintain a list of cache_detail and 249 * a current pointer into that list and into the table 250 * for that entry. 251 * 252 * Each time clean_cache is called it finds the next non-empty entry 253 * in the current table and walks the list in that entry 254 * looking for entries that can be removed. 255 * 256 * An entry gets removed if: 257 * - The expiry is before current time 258 * - The last_refresh time is before the flush_time for that cache 259 * 260 * later we might drop old entries with non-NEVER expiry if that table 261 * is getting 'full' for some definition of 'full' 262 * 263 * The question of "how often to scan a table" is an interesting one 264 * and is answered in part by the use of the "nextcheck" field in the 265 * cache_detail. 266 * When a scan of a table begins, the nextcheck field is set to a time 267 * that is well into the future. 268 * While scanning, if an expiry time is found that is earlier than the 269 * current nextcheck time, nextcheck is set to that expiry time. 270 * If the flush_time is ever set to a time earlier than the nextcheck 271 * time, the nextcheck time is then set to that flush_time. 272 * 273 * A table is then only scanned if the current time is at least 274 * the nextcheck time. 275 * 276 */ 277 278 static LIST_HEAD(cache_list); 279 static DEFINE_SPINLOCK(cache_list_lock); 280 static struct cache_detail *current_detail; 281 static int current_index; 282 283 static struct file_operations cache_file_operations; 284 static struct file_operations content_file_operations; 285 static struct file_operations cache_flush_operations; 286 287 static void do_cache_clean(void *data); 288 static DECLARE_WORK(cache_cleaner, do_cache_clean, NULL); 289 290 void cache_register(struct cache_detail *cd) 291 { 292 cd->proc_ent = proc_mkdir(cd->name, proc_net_rpc); 293 if (cd->proc_ent) { 294 struct proc_dir_entry *p; 295 cd->proc_ent->owner = cd->owner; 296 cd->channel_ent = cd->content_ent = NULL; 297 298 p = create_proc_entry("flush", S_IFREG|S_IRUSR|S_IWUSR, 299 cd->proc_ent); 300 cd->flush_ent = p; 301 if (p) { 302 p->proc_fops = &cache_flush_operations; 303 p->owner = cd->owner; 304 p->data = cd; 305 } 306 307 if (cd->cache_request || cd->cache_parse) { 308 p = create_proc_entry("channel", S_IFREG|S_IRUSR|S_IWUSR, 309 cd->proc_ent); 310 cd->channel_ent = p; 311 if (p) { 312 p->proc_fops = &cache_file_operations; 313 p->owner = cd->owner; 314 p->data = cd; 315 } 316 } 317 if (cd->cache_show) { 318 p = create_proc_entry("content", S_IFREG|S_IRUSR|S_IWUSR, 319 cd->proc_ent); 320 cd->content_ent = p; 321 if (p) { 322 p->proc_fops = &content_file_operations; 323 p->owner = cd->owner; 324 p->data = cd; 325 } 326 } 327 } 328 rwlock_init(&cd->hash_lock); 329 INIT_LIST_HEAD(&cd->queue); 330 spin_lock(&cache_list_lock); 331 cd->nextcheck = 0; 332 cd->entries = 0; 333 atomic_set(&cd->readers, 0); 334 cd->last_close = 0; 335 cd->last_warn = -1; 336 list_add(&cd->others, &cache_list); 337 spin_unlock(&cache_list_lock); 338 339 /* start the cleaning process */ 340 schedule_work(&cache_cleaner); 341 } 342 343 int cache_unregister(struct cache_detail *cd) 344 { 345 cache_purge(cd); 346 spin_lock(&cache_list_lock); 347 write_lock(&cd->hash_lock); 348 if (cd->entries || atomic_read(&cd->inuse)) { 349 write_unlock(&cd->hash_lock); 350 spin_unlock(&cache_list_lock); 351 return -EBUSY; 352 } 353 if (current_detail == cd) 354 current_detail = NULL; 355 list_del_init(&cd->others); 356 write_unlock(&cd->hash_lock); 357 spin_unlock(&cache_list_lock); 358 if (cd->proc_ent) { 359 if (cd->flush_ent) 360 remove_proc_entry("flush", cd->proc_ent); 361 if (cd->channel_ent) 362 remove_proc_entry("channel", cd->proc_ent); 363 if (cd->content_ent) 364 remove_proc_entry("content", cd->proc_ent); 365 366 cd->proc_ent = NULL; 367 remove_proc_entry(cd->name, proc_net_rpc); 368 } 369 if (list_empty(&cache_list)) { 370 /* module must be being unloaded so its safe to kill the worker */ 371 cancel_delayed_work(&cache_cleaner); 372 flush_scheduled_work(); 373 } 374 return 0; 375 } 376 377 /* clean cache tries to find something to clean 378 * and cleans it. 379 * It returns 1 if it cleaned something, 380 * 0 if it didn't find anything this time 381 * -1 if it fell off the end of the list. 382 */ 383 static int cache_clean(void) 384 { 385 int rv = 0; 386 struct list_head *next; 387 388 spin_lock(&cache_list_lock); 389 390 /* find a suitable table if we don't already have one */ 391 while (current_detail == NULL || 392 current_index >= current_detail->hash_size) { 393 if (current_detail) 394 next = current_detail->others.next; 395 else 396 next = cache_list.next; 397 if (next == &cache_list) { 398 current_detail = NULL; 399 spin_unlock(&cache_list_lock); 400 return -1; 401 } 402 current_detail = list_entry(next, struct cache_detail, others); 403 if (current_detail->nextcheck > get_seconds()) 404 current_index = current_detail->hash_size; 405 else { 406 current_index = 0; 407 current_detail->nextcheck = get_seconds()+30*60; 408 } 409 } 410 411 /* find a non-empty bucket in the table */ 412 while (current_detail && 413 current_index < current_detail->hash_size && 414 current_detail->hash_table[current_index] == NULL) 415 current_index++; 416 417 /* find a cleanable entry in the bucket and clean it, or set to next bucket */ 418 419 if (current_detail && current_index < current_detail->hash_size) { 420 struct cache_head *ch, **cp; 421 struct cache_detail *d; 422 423 write_lock(¤t_detail->hash_lock); 424 425 /* Ok, now to clean this strand */ 426 427 cp = & current_detail->hash_table[current_index]; 428 ch = *cp; 429 for (; ch; cp= & ch->next, ch= *cp) { 430 if (current_detail->nextcheck > ch->expiry_time) 431 current_detail->nextcheck = ch->expiry_time+1; 432 if (ch->expiry_time >= get_seconds() 433 && ch->last_refresh >= current_detail->flush_time 434 ) 435 continue; 436 if (test_and_clear_bit(CACHE_PENDING, &ch->flags)) 437 queue_loose(current_detail, ch); 438 439 if (atomic_read(&ch->ref.refcount) == 1) 440 break; 441 } 442 if (ch) { 443 *cp = ch->next; 444 ch->next = NULL; 445 current_detail->entries--; 446 rv = 1; 447 } 448 write_unlock(¤t_detail->hash_lock); 449 d = current_detail; 450 if (!ch) 451 current_index ++; 452 spin_unlock(&cache_list_lock); 453 if (ch) 454 cache_put(ch, d); 455 } else 456 spin_unlock(&cache_list_lock); 457 458 return rv; 459 } 460 461 /* 462 * We want to regularly clean the cache, so we need to schedule some work ... 463 */ 464 static void do_cache_clean(void *data) 465 { 466 int delay = 5; 467 if (cache_clean() == -1) 468 delay = 30*HZ; 469 470 if (list_empty(&cache_list)) 471 delay = 0; 472 473 if (delay) 474 schedule_delayed_work(&cache_cleaner, delay); 475 } 476 477 478 /* 479 * Clean all caches promptly. This just calls cache_clean 480 * repeatedly until we are sure that every cache has had a chance to 481 * be fully cleaned 482 */ 483 void cache_flush(void) 484 { 485 while (cache_clean() != -1) 486 cond_resched(); 487 while (cache_clean() != -1) 488 cond_resched(); 489 } 490 491 void cache_purge(struct cache_detail *detail) 492 { 493 detail->flush_time = LONG_MAX; 494 detail->nextcheck = get_seconds(); 495 cache_flush(); 496 detail->flush_time = 1; 497 } 498 499 500 501 /* 502 * Deferral and Revisiting of Requests. 503 * 504 * If a cache lookup finds a pending entry, we 505 * need to defer the request and revisit it later. 506 * All deferred requests are stored in a hash table, 507 * indexed by "struct cache_head *". 508 * As it may be wasteful to store a whole request 509 * structure, we allow the request to provide a 510 * deferred form, which must contain a 511 * 'struct cache_deferred_req' 512 * This cache_deferred_req contains a method to allow 513 * it to be revisited when cache info is available 514 */ 515 516 #define DFR_HASHSIZE (PAGE_SIZE/sizeof(struct list_head)) 517 #define DFR_HASH(item) ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE) 518 519 #define DFR_MAX 300 /* ??? */ 520 521 static DEFINE_SPINLOCK(cache_defer_lock); 522 static LIST_HEAD(cache_defer_list); 523 static struct list_head cache_defer_hash[DFR_HASHSIZE]; 524 static int cache_defer_cnt; 525 526 static void cache_defer_req(struct cache_req *req, struct cache_head *item) 527 { 528 struct cache_deferred_req *dreq; 529 int hash = DFR_HASH(item); 530 531 dreq = req->defer(req); 532 if (dreq == NULL) 533 return; 534 535 dreq->item = item; 536 dreq->recv_time = get_seconds(); 537 538 spin_lock(&cache_defer_lock); 539 540 list_add(&dreq->recent, &cache_defer_list); 541 542 if (cache_defer_hash[hash].next == NULL) 543 INIT_LIST_HEAD(&cache_defer_hash[hash]); 544 list_add(&dreq->hash, &cache_defer_hash[hash]); 545 546 /* it is in, now maybe clean up */ 547 dreq = NULL; 548 if (++cache_defer_cnt > DFR_MAX) { 549 /* too much in the cache, randomly drop 550 * first or last 551 */ 552 if (net_random()&1) 553 dreq = list_entry(cache_defer_list.next, 554 struct cache_deferred_req, 555 recent); 556 else 557 dreq = list_entry(cache_defer_list.prev, 558 struct cache_deferred_req, 559 recent); 560 list_del(&dreq->recent); 561 list_del(&dreq->hash); 562 cache_defer_cnt--; 563 } 564 spin_unlock(&cache_defer_lock); 565 566 if (dreq) { 567 /* there was one too many */ 568 dreq->revisit(dreq, 1); 569 } 570 if (!test_bit(CACHE_PENDING, &item->flags)) { 571 /* must have just been validated... */ 572 cache_revisit_request(item); 573 } 574 } 575 576 static void cache_revisit_request(struct cache_head *item) 577 { 578 struct cache_deferred_req *dreq; 579 struct list_head pending; 580 581 struct list_head *lp; 582 int hash = DFR_HASH(item); 583 584 INIT_LIST_HEAD(&pending); 585 spin_lock(&cache_defer_lock); 586 587 lp = cache_defer_hash[hash].next; 588 if (lp) { 589 while (lp != &cache_defer_hash[hash]) { 590 dreq = list_entry(lp, struct cache_deferred_req, hash); 591 lp = lp->next; 592 if (dreq->item == item) { 593 list_del(&dreq->hash); 594 list_move(&dreq->recent, &pending); 595 cache_defer_cnt--; 596 } 597 } 598 } 599 spin_unlock(&cache_defer_lock); 600 601 while (!list_empty(&pending)) { 602 dreq = list_entry(pending.next, struct cache_deferred_req, recent); 603 list_del_init(&dreq->recent); 604 dreq->revisit(dreq, 0); 605 } 606 } 607 608 void cache_clean_deferred(void *owner) 609 { 610 struct cache_deferred_req *dreq, *tmp; 611 struct list_head pending; 612 613 614 INIT_LIST_HEAD(&pending); 615 spin_lock(&cache_defer_lock); 616 617 list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) { 618 if (dreq->owner == owner) { 619 list_del(&dreq->hash); 620 list_move(&dreq->recent, &pending); 621 cache_defer_cnt--; 622 } 623 } 624 spin_unlock(&cache_defer_lock); 625 626 while (!list_empty(&pending)) { 627 dreq = list_entry(pending.next, struct cache_deferred_req, recent); 628 list_del_init(&dreq->recent); 629 dreq->revisit(dreq, 1); 630 } 631 } 632 633 /* 634 * communicate with user-space 635 * 636 * We have a magic /proc file - /proc/sunrpc/cache 637 * On read, you get a full request, or block 638 * On write, an update request is processed 639 * Poll works if anything to read, and always allows write 640 * 641 * Implemented by linked list of requests. Each open file has 642 * a ->private that also exists in this list. New request are added 643 * to the end and may wakeup and preceding readers. 644 * New readers are added to the head. If, on read, an item is found with 645 * CACHE_UPCALLING clear, we free it from the list. 646 * 647 */ 648 649 static DEFINE_SPINLOCK(queue_lock); 650 static DEFINE_MUTEX(queue_io_mutex); 651 652 struct cache_queue { 653 struct list_head list; 654 int reader; /* if 0, then request */ 655 }; 656 struct cache_request { 657 struct cache_queue q; 658 struct cache_head *item; 659 char * buf; 660 int len; 661 int readers; 662 }; 663 struct cache_reader { 664 struct cache_queue q; 665 int offset; /* if non-0, we have a refcnt on next request */ 666 }; 667 668 static ssize_t 669 cache_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) 670 { 671 struct cache_reader *rp = filp->private_data; 672 struct cache_request *rq; 673 struct cache_detail *cd = PDE(filp->f_dentry->d_inode)->data; 674 int err; 675 676 if (count == 0) 677 return 0; 678 679 mutex_lock(&queue_io_mutex); /* protect against multiple concurrent 680 * readers on this file */ 681 again: 682 spin_lock(&queue_lock); 683 /* need to find next request */ 684 while (rp->q.list.next != &cd->queue && 685 list_entry(rp->q.list.next, struct cache_queue, list) 686 ->reader) { 687 struct list_head *next = rp->q.list.next; 688 list_move(&rp->q.list, next); 689 } 690 if (rp->q.list.next == &cd->queue) { 691 spin_unlock(&queue_lock); 692 mutex_unlock(&queue_io_mutex); 693 BUG_ON(rp->offset); 694 return 0; 695 } 696 rq = container_of(rp->q.list.next, struct cache_request, q.list); 697 BUG_ON(rq->q.reader); 698 if (rp->offset == 0) 699 rq->readers++; 700 spin_unlock(&queue_lock); 701 702 if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) { 703 err = -EAGAIN; 704 spin_lock(&queue_lock); 705 list_move(&rp->q.list, &rq->q.list); 706 spin_unlock(&queue_lock); 707 } else { 708 if (rp->offset + count > rq->len) 709 count = rq->len - rp->offset; 710 err = -EFAULT; 711 if (copy_to_user(buf, rq->buf + rp->offset, count)) 712 goto out; 713 rp->offset += count; 714 if (rp->offset >= rq->len) { 715 rp->offset = 0; 716 spin_lock(&queue_lock); 717 list_move(&rp->q.list, &rq->q.list); 718 spin_unlock(&queue_lock); 719 } 720 err = 0; 721 } 722 out: 723 if (rp->offset == 0) { 724 /* need to release rq */ 725 spin_lock(&queue_lock); 726 rq->readers--; 727 if (rq->readers == 0 && 728 !test_bit(CACHE_PENDING, &rq->item->flags)) { 729 list_del(&rq->q.list); 730 spin_unlock(&queue_lock); 731 cache_put(rq->item, cd); 732 kfree(rq->buf); 733 kfree(rq); 734 } else 735 spin_unlock(&queue_lock); 736 } 737 if (err == -EAGAIN) 738 goto again; 739 mutex_unlock(&queue_io_mutex); 740 return err ? err : count; 741 } 742 743 static char write_buf[8192]; /* protected by queue_io_mutex */ 744 745 static ssize_t 746 cache_write(struct file *filp, const char __user *buf, size_t count, 747 loff_t *ppos) 748 { 749 int err; 750 struct cache_detail *cd = PDE(filp->f_dentry->d_inode)->data; 751 752 if (count == 0) 753 return 0; 754 if (count >= sizeof(write_buf)) 755 return -EINVAL; 756 757 mutex_lock(&queue_io_mutex); 758 759 if (copy_from_user(write_buf, buf, count)) { 760 mutex_unlock(&queue_io_mutex); 761 return -EFAULT; 762 } 763 write_buf[count] = '\0'; 764 if (cd->cache_parse) 765 err = cd->cache_parse(cd, write_buf, count); 766 else 767 err = -EINVAL; 768 769 mutex_unlock(&queue_io_mutex); 770 return err ? err : count; 771 } 772 773 static DECLARE_WAIT_QUEUE_HEAD(queue_wait); 774 775 static unsigned int 776 cache_poll(struct file *filp, poll_table *wait) 777 { 778 unsigned int mask; 779 struct cache_reader *rp = filp->private_data; 780 struct cache_queue *cq; 781 struct cache_detail *cd = PDE(filp->f_dentry->d_inode)->data; 782 783 poll_wait(filp, &queue_wait, wait); 784 785 /* alway allow write */ 786 mask = POLL_OUT | POLLWRNORM; 787 788 if (!rp) 789 return mask; 790 791 spin_lock(&queue_lock); 792 793 for (cq= &rp->q; &cq->list != &cd->queue; 794 cq = list_entry(cq->list.next, struct cache_queue, list)) 795 if (!cq->reader) { 796 mask |= POLLIN | POLLRDNORM; 797 break; 798 } 799 spin_unlock(&queue_lock); 800 return mask; 801 } 802 803 static int 804 cache_ioctl(struct inode *ino, struct file *filp, 805 unsigned int cmd, unsigned long arg) 806 { 807 int len = 0; 808 struct cache_reader *rp = filp->private_data; 809 struct cache_queue *cq; 810 struct cache_detail *cd = PDE(ino)->data; 811 812 if (cmd != FIONREAD || !rp) 813 return -EINVAL; 814 815 spin_lock(&queue_lock); 816 817 /* only find the length remaining in current request, 818 * or the length of the next request 819 */ 820 for (cq= &rp->q; &cq->list != &cd->queue; 821 cq = list_entry(cq->list.next, struct cache_queue, list)) 822 if (!cq->reader) { 823 struct cache_request *cr = 824 container_of(cq, struct cache_request, q); 825 len = cr->len - rp->offset; 826 break; 827 } 828 spin_unlock(&queue_lock); 829 830 return put_user(len, (int __user *)arg); 831 } 832 833 static int 834 cache_open(struct inode *inode, struct file *filp) 835 { 836 struct cache_reader *rp = NULL; 837 838 nonseekable_open(inode, filp); 839 if (filp->f_mode & FMODE_READ) { 840 struct cache_detail *cd = PDE(inode)->data; 841 842 rp = kmalloc(sizeof(*rp), GFP_KERNEL); 843 if (!rp) 844 return -ENOMEM; 845 rp->offset = 0; 846 rp->q.reader = 1; 847 atomic_inc(&cd->readers); 848 spin_lock(&queue_lock); 849 list_add(&rp->q.list, &cd->queue); 850 spin_unlock(&queue_lock); 851 } 852 filp->private_data = rp; 853 return 0; 854 } 855 856 static int 857 cache_release(struct inode *inode, struct file *filp) 858 { 859 struct cache_reader *rp = filp->private_data; 860 struct cache_detail *cd = PDE(inode)->data; 861 862 if (rp) { 863 spin_lock(&queue_lock); 864 if (rp->offset) { 865 struct cache_queue *cq; 866 for (cq= &rp->q; &cq->list != &cd->queue; 867 cq = list_entry(cq->list.next, struct cache_queue, list)) 868 if (!cq->reader) { 869 container_of(cq, struct cache_request, q) 870 ->readers--; 871 break; 872 } 873 rp->offset = 0; 874 } 875 list_del(&rp->q.list); 876 spin_unlock(&queue_lock); 877 878 filp->private_data = NULL; 879 kfree(rp); 880 881 cd->last_close = get_seconds(); 882 atomic_dec(&cd->readers); 883 } 884 return 0; 885 } 886 887 888 889 static struct file_operations cache_file_operations = { 890 .owner = THIS_MODULE, 891 .llseek = no_llseek, 892 .read = cache_read, 893 .write = cache_write, 894 .poll = cache_poll, 895 .ioctl = cache_ioctl, /* for FIONREAD */ 896 .open = cache_open, 897 .release = cache_release, 898 }; 899 900 901 static void queue_loose(struct cache_detail *detail, struct cache_head *ch) 902 { 903 struct cache_queue *cq; 904 spin_lock(&queue_lock); 905 list_for_each_entry(cq, &detail->queue, list) 906 if (!cq->reader) { 907 struct cache_request *cr = container_of(cq, struct cache_request, q); 908 if (cr->item != ch) 909 continue; 910 if (cr->readers != 0) 911 continue; 912 list_del(&cr->q.list); 913 spin_unlock(&queue_lock); 914 cache_put(cr->item, detail); 915 kfree(cr->buf); 916 kfree(cr); 917 return; 918 } 919 spin_unlock(&queue_lock); 920 } 921 922 /* 923 * Support routines for text-based upcalls. 924 * Fields are separated by spaces. 925 * Fields are either mangled to quote space tab newline slosh with slosh 926 * or a hexified with a leading \x 927 * Record is terminated with newline. 928 * 929 */ 930 931 void qword_add(char **bpp, int *lp, char *str) 932 { 933 char *bp = *bpp; 934 int len = *lp; 935 char c; 936 937 if (len < 0) return; 938 939 while ((c=*str++) && len) 940 switch(c) { 941 case ' ': 942 case '\t': 943 case '\n': 944 case '\\': 945 if (len >= 4) { 946 *bp++ = '\\'; 947 *bp++ = '0' + ((c & 0300)>>6); 948 *bp++ = '0' + ((c & 0070)>>3); 949 *bp++ = '0' + ((c & 0007)>>0); 950 } 951 len -= 4; 952 break; 953 default: 954 *bp++ = c; 955 len--; 956 } 957 if (c || len <1) len = -1; 958 else { 959 *bp++ = ' '; 960 len--; 961 } 962 *bpp = bp; 963 *lp = len; 964 } 965 966 void qword_addhex(char **bpp, int *lp, char *buf, int blen) 967 { 968 char *bp = *bpp; 969 int len = *lp; 970 971 if (len < 0) return; 972 973 if (len > 2) { 974 *bp++ = '\\'; 975 *bp++ = 'x'; 976 len -= 2; 977 while (blen && len >= 2) { 978 unsigned char c = *buf++; 979 *bp++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1); 980 *bp++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1); 981 len -= 2; 982 blen--; 983 } 984 } 985 if (blen || len<1) len = -1; 986 else { 987 *bp++ = ' '; 988 len--; 989 } 990 *bpp = bp; 991 *lp = len; 992 } 993 994 static void warn_no_listener(struct cache_detail *detail) 995 { 996 if (detail->last_warn != detail->last_close) { 997 detail->last_warn = detail->last_close; 998 if (detail->warn_no_listener) 999 detail->warn_no_listener(detail); 1000 } 1001 } 1002 1003 /* 1004 * register an upcall request to user-space. 1005 * Each request is at most one page long. 1006 */ 1007 static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h) 1008 { 1009 1010 char *buf; 1011 struct cache_request *crq; 1012 char *bp; 1013 int len; 1014 1015 if (detail->cache_request == NULL) 1016 return -EINVAL; 1017 1018 if (atomic_read(&detail->readers) == 0 && 1019 detail->last_close < get_seconds() - 30) { 1020 warn_no_listener(detail); 1021 return -EINVAL; 1022 } 1023 1024 buf = kmalloc(PAGE_SIZE, GFP_KERNEL); 1025 if (!buf) 1026 return -EAGAIN; 1027 1028 crq = kmalloc(sizeof (*crq), GFP_KERNEL); 1029 if (!crq) { 1030 kfree(buf); 1031 return -EAGAIN; 1032 } 1033 1034 bp = buf; len = PAGE_SIZE; 1035 1036 detail->cache_request(detail, h, &bp, &len); 1037 1038 if (len < 0) { 1039 kfree(buf); 1040 kfree(crq); 1041 return -EAGAIN; 1042 } 1043 crq->q.reader = 0; 1044 crq->item = cache_get(h); 1045 crq->buf = buf; 1046 crq->len = PAGE_SIZE - len; 1047 crq->readers = 0; 1048 spin_lock(&queue_lock); 1049 list_add_tail(&crq->q.list, &detail->queue); 1050 spin_unlock(&queue_lock); 1051 wake_up(&queue_wait); 1052 return 0; 1053 } 1054 1055 /* 1056 * parse a message from user-space and pass it 1057 * to an appropriate cache 1058 * Messages are, like requests, separated into fields by 1059 * spaces and dequotes as \xHEXSTRING or embedded \nnn octal 1060 * 1061 * Message is 1062 * reply cachename expiry key ... content.... 1063 * 1064 * key and content are both parsed by cache 1065 */ 1066 1067 #define isodigit(c) (isdigit(c) && c <= '7') 1068 int qword_get(char **bpp, char *dest, int bufsize) 1069 { 1070 /* return bytes copied, or -1 on error */ 1071 char *bp = *bpp; 1072 int len = 0; 1073 1074 while (*bp == ' ') bp++; 1075 1076 if (bp[0] == '\\' && bp[1] == 'x') { 1077 /* HEX STRING */ 1078 bp += 2; 1079 while (isxdigit(bp[0]) && isxdigit(bp[1]) && len < bufsize) { 1080 int byte = isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10; 1081 bp++; 1082 byte <<= 4; 1083 byte |= isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10; 1084 *dest++ = byte; 1085 bp++; 1086 len++; 1087 } 1088 } else { 1089 /* text with \nnn octal quoting */ 1090 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) { 1091 if (*bp == '\\' && 1092 isodigit(bp[1]) && (bp[1] <= '3') && 1093 isodigit(bp[2]) && 1094 isodigit(bp[3])) { 1095 int byte = (*++bp -'0'); 1096 bp++; 1097 byte = (byte << 3) | (*bp++ - '0'); 1098 byte = (byte << 3) | (*bp++ - '0'); 1099 *dest++ = byte; 1100 len++; 1101 } else { 1102 *dest++ = *bp++; 1103 len++; 1104 } 1105 } 1106 } 1107 1108 if (*bp != ' ' && *bp != '\n' && *bp != '\0') 1109 return -1; 1110 while (*bp == ' ') bp++; 1111 *bpp = bp; 1112 *dest = '\0'; 1113 return len; 1114 } 1115 1116 1117 /* 1118 * support /proc/sunrpc/cache/$CACHENAME/content 1119 * as a seqfile. 1120 * We call ->cache_show passing NULL for the item to 1121 * get a header, then pass each real item in the cache 1122 */ 1123 1124 struct handle { 1125 struct cache_detail *cd; 1126 }; 1127 1128 static void *c_start(struct seq_file *m, loff_t *pos) 1129 { 1130 loff_t n = *pos; 1131 unsigned hash, entry; 1132 struct cache_head *ch; 1133 struct cache_detail *cd = ((struct handle*)m->private)->cd; 1134 1135 1136 read_lock(&cd->hash_lock); 1137 if (!n--) 1138 return SEQ_START_TOKEN; 1139 hash = n >> 32; 1140 entry = n & ((1LL<<32) - 1); 1141 1142 for (ch=cd->hash_table[hash]; ch; ch=ch->next) 1143 if (!entry--) 1144 return ch; 1145 n &= ~((1LL<<32) - 1); 1146 do { 1147 hash++; 1148 n += 1LL<<32; 1149 } while(hash < cd->hash_size && 1150 cd->hash_table[hash]==NULL); 1151 if (hash >= cd->hash_size) 1152 return NULL; 1153 *pos = n+1; 1154 return cd->hash_table[hash]; 1155 } 1156 1157 static void *c_next(struct seq_file *m, void *p, loff_t *pos) 1158 { 1159 struct cache_head *ch = p; 1160 int hash = (*pos >> 32); 1161 struct cache_detail *cd = ((struct handle*)m->private)->cd; 1162 1163 if (p == SEQ_START_TOKEN) 1164 hash = 0; 1165 else if (ch->next == NULL) { 1166 hash++; 1167 *pos += 1LL<<32; 1168 } else { 1169 ++*pos; 1170 return ch->next; 1171 } 1172 *pos &= ~((1LL<<32) - 1); 1173 while (hash < cd->hash_size && 1174 cd->hash_table[hash] == NULL) { 1175 hash++; 1176 *pos += 1LL<<32; 1177 } 1178 if (hash >= cd->hash_size) 1179 return NULL; 1180 ++*pos; 1181 return cd->hash_table[hash]; 1182 } 1183 1184 static void c_stop(struct seq_file *m, void *p) 1185 { 1186 struct cache_detail *cd = ((struct handle*)m->private)->cd; 1187 read_unlock(&cd->hash_lock); 1188 } 1189 1190 static int c_show(struct seq_file *m, void *p) 1191 { 1192 struct cache_head *cp = p; 1193 struct cache_detail *cd = ((struct handle*)m->private)->cd; 1194 1195 if (p == SEQ_START_TOKEN) 1196 return cd->cache_show(m, cd, NULL); 1197 1198 ifdebug(CACHE) 1199 seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n", 1200 cp->expiry_time, atomic_read(&cp->ref.refcount), cp->flags); 1201 cache_get(cp); 1202 if (cache_check(cd, cp, NULL)) 1203 /* cache_check does a cache_put on failure */ 1204 seq_printf(m, "# "); 1205 else 1206 cache_put(cp, cd); 1207 1208 return cd->cache_show(m, cd, cp); 1209 } 1210 1211 static struct seq_operations cache_content_op = { 1212 .start = c_start, 1213 .next = c_next, 1214 .stop = c_stop, 1215 .show = c_show, 1216 }; 1217 1218 static int content_open(struct inode *inode, struct file *file) 1219 { 1220 int res; 1221 struct handle *han; 1222 struct cache_detail *cd = PDE(inode)->data; 1223 1224 han = kmalloc(sizeof(*han), GFP_KERNEL); 1225 if (han == NULL) 1226 return -ENOMEM; 1227 1228 han->cd = cd; 1229 1230 res = seq_open(file, &cache_content_op); 1231 if (res) 1232 kfree(han); 1233 else 1234 ((struct seq_file *)file->private_data)->private = han; 1235 1236 return res; 1237 } 1238 static int content_release(struct inode *inode, struct file *file) 1239 { 1240 struct seq_file *m = (struct seq_file *)file->private_data; 1241 struct handle *han = m->private; 1242 kfree(han); 1243 m->private = NULL; 1244 return seq_release(inode, file); 1245 } 1246 1247 static struct file_operations content_file_operations = { 1248 .open = content_open, 1249 .read = seq_read, 1250 .llseek = seq_lseek, 1251 .release = content_release, 1252 }; 1253 1254 static ssize_t read_flush(struct file *file, char __user *buf, 1255 size_t count, loff_t *ppos) 1256 { 1257 struct cache_detail *cd = PDE(file->f_dentry->d_inode)->data; 1258 char tbuf[20]; 1259 unsigned long p = *ppos; 1260 int len; 1261 1262 sprintf(tbuf, "%lu\n", cd->flush_time); 1263 len = strlen(tbuf); 1264 if (p >= len) 1265 return 0; 1266 len -= p; 1267 if (len > count) len = count; 1268 if (copy_to_user(buf, (void*)(tbuf+p), len)) 1269 len = -EFAULT; 1270 else 1271 *ppos += len; 1272 return len; 1273 } 1274 1275 static ssize_t write_flush(struct file * file, const char __user * buf, 1276 size_t count, loff_t *ppos) 1277 { 1278 struct cache_detail *cd = PDE(file->f_dentry->d_inode)->data; 1279 char tbuf[20]; 1280 char *ep; 1281 long flushtime; 1282 if (*ppos || count > sizeof(tbuf)-1) 1283 return -EINVAL; 1284 if (copy_from_user(tbuf, buf, count)) 1285 return -EFAULT; 1286 tbuf[count] = 0; 1287 flushtime = simple_strtoul(tbuf, &ep, 0); 1288 if (*ep && *ep != '\n') 1289 return -EINVAL; 1290 1291 cd->flush_time = flushtime; 1292 cd->nextcheck = get_seconds(); 1293 cache_flush(); 1294 1295 *ppos += count; 1296 return count; 1297 } 1298 1299 static struct file_operations cache_flush_operations = { 1300 .open = nonseekable_open, 1301 .read = read_flush, 1302 .write = write_flush, 1303 }; 1304