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