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 BUG_ON(rp->offset); 579 return 0; 580 } 581 rq = container_of(rp->q.list.next, struct cache_request, q.list); 582 BUG_ON(rq->q.reader); 583 if (rp->offset == 0) 584 rq->readers++; 585 spin_unlock(&queue_lock); 586 587 if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) { 588 err = -EAGAIN; 589 spin_lock(&queue_lock); 590 list_move(&rp->q.list, &rq->q.list); 591 spin_unlock(&queue_lock); 592 } else { 593 if (rp->offset + count > rq->len) 594 count = rq->len - rp->offset; 595 err = -EFAULT; 596 if (copy_to_user(buf, rq->buf + rp->offset, count)) 597 goto out; 598 rp->offset += count; 599 if (rp->offset >= rq->len) { 600 rp->offset = 0; 601 spin_lock(&queue_lock); 602 list_move(&rp->q.list, &rq->q.list); 603 spin_unlock(&queue_lock); 604 } 605 err = 0; 606 } 607 out: 608 if (rp->offset == 0) { 609 /* need to release rq */ 610 spin_lock(&queue_lock); 611 rq->readers--; 612 if (rq->readers == 0 && 613 !test_bit(CACHE_PENDING, &rq->item->flags)) { 614 list_del(&rq->q.list); 615 spin_unlock(&queue_lock); 616 cd->cache_put(rq->item, cd); 617 kfree(rq->buf); 618 kfree(rq); 619 } else 620 spin_unlock(&queue_lock); 621 } 622 if (err == -EAGAIN) 623 goto again; 624 up(&queue_io_sem); 625 return err ? err : count; 626 } 627 628 static char write_buf[8192]; /* protected by queue_io_sem */ 629 630 static ssize_t 631 cache_write(struct file *filp, const char __user *buf, size_t count, 632 loff_t *ppos) 633 { 634 int err; 635 struct cache_detail *cd = PDE(filp->f_dentry->d_inode)->data; 636 637 if (count == 0) 638 return 0; 639 if (count >= sizeof(write_buf)) 640 return -EINVAL; 641 642 down(&queue_io_sem); 643 644 if (copy_from_user(write_buf, buf, count)) { 645 up(&queue_io_sem); 646 return -EFAULT; 647 } 648 write_buf[count] = '\0'; 649 if (cd->cache_parse) 650 err = cd->cache_parse(cd, write_buf, count); 651 else 652 err = -EINVAL; 653 654 up(&queue_io_sem); 655 return err ? err : count; 656 } 657 658 static DECLARE_WAIT_QUEUE_HEAD(queue_wait); 659 660 static unsigned int 661 cache_poll(struct file *filp, poll_table *wait) 662 { 663 unsigned int mask; 664 struct cache_reader *rp = filp->private_data; 665 struct cache_queue *cq; 666 struct cache_detail *cd = PDE(filp->f_dentry->d_inode)->data; 667 668 poll_wait(filp, &queue_wait, wait); 669 670 /* alway allow write */ 671 mask = POLL_OUT | POLLWRNORM; 672 673 if (!rp) 674 return mask; 675 676 spin_lock(&queue_lock); 677 678 for (cq= &rp->q; &cq->list != &cd->queue; 679 cq = list_entry(cq->list.next, struct cache_queue, list)) 680 if (!cq->reader) { 681 mask |= POLLIN | POLLRDNORM; 682 break; 683 } 684 spin_unlock(&queue_lock); 685 return mask; 686 } 687 688 static int 689 cache_ioctl(struct inode *ino, struct file *filp, 690 unsigned int cmd, unsigned long arg) 691 { 692 int len = 0; 693 struct cache_reader *rp = filp->private_data; 694 struct cache_queue *cq; 695 struct cache_detail *cd = PDE(ino)->data; 696 697 if (cmd != FIONREAD || !rp) 698 return -EINVAL; 699 700 spin_lock(&queue_lock); 701 702 /* only find the length remaining in current request, 703 * or the length of the next request 704 */ 705 for (cq= &rp->q; &cq->list != &cd->queue; 706 cq = list_entry(cq->list.next, struct cache_queue, list)) 707 if (!cq->reader) { 708 struct cache_request *cr = 709 container_of(cq, struct cache_request, q); 710 len = cr->len - rp->offset; 711 break; 712 } 713 spin_unlock(&queue_lock); 714 715 return put_user(len, (int __user *)arg); 716 } 717 718 static int 719 cache_open(struct inode *inode, struct file *filp) 720 { 721 struct cache_reader *rp = NULL; 722 723 nonseekable_open(inode, filp); 724 if (filp->f_mode & FMODE_READ) { 725 struct cache_detail *cd = PDE(inode)->data; 726 727 rp = kmalloc(sizeof(*rp), GFP_KERNEL); 728 if (!rp) 729 return -ENOMEM; 730 rp->offset = 0; 731 rp->q.reader = 1; 732 atomic_inc(&cd->readers); 733 spin_lock(&queue_lock); 734 list_add(&rp->q.list, &cd->queue); 735 spin_unlock(&queue_lock); 736 } 737 filp->private_data = rp; 738 return 0; 739 } 740 741 static int 742 cache_release(struct inode *inode, struct file *filp) 743 { 744 struct cache_reader *rp = filp->private_data; 745 struct cache_detail *cd = PDE(inode)->data; 746 747 if (rp) { 748 spin_lock(&queue_lock); 749 if (rp->offset) { 750 struct cache_queue *cq; 751 for (cq= &rp->q; &cq->list != &cd->queue; 752 cq = list_entry(cq->list.next, struct cache_queue, list)) 753 if (!cq->reader) { 754 container_of(cq, struct cache_request, q) 755 ->readers--; 756 break; 757 } 758 rp->offset = 0; 759 } 760 list_del(&rp->q.list); 761 spin_unlock(&queue_lock); 762 763 filp->private_data = NULL; 764 kfree(rp); 765 766 cd->last_close = get_seconds(); 767 atomic_dec(&cd->readers); 768 } 769 return 0; 770 } 771 772 773 774 static struct file_operations cache_file_operations = { 775 .owner = THIS_MODULE, 776 .llseek = no_llseek, 777 .read = cache_read, 778 .write = cache_write, 779 .poll = cache_poll, 780 .ioctl = cache_ioctl, /* for FIONREAD */ 781 .open = cache_open, 782 .release = cache_release, 783 }; 784 785 786 static void queue_loose(struct cache_detail *detail, struct cache_head *ch) 787 { 788 struct cache_queue *cq; 789 spin_lock(&queue_lock); 790 list_for_each_entry(cq, &detail->queue, list) 791 if (!cq->reader) { 792 struct cache_request *cr = container_of(cq, struct cache_request, q); 793 if (cr->item != ch) 794 continue; 795 if (cr->readers != 0) 796 break; 797 list_del(&cr->q.list); 798 spin_unlock(&queue_lock); 799 detail->cache_put(cr->item, detail); 800 kfree(cr->buf); 801 kfree(cr); 802 return; 803 } 804 spin_unlock(&queue_lock); 805 } 806 807 /* 808 * Support routines for text-based upcalls. 809 * Fields are separated by spaces. 810 * Fields are either mangled to quote space tab newline slosh with slosh 811 * or a hexified with a leading \x 812 * Record is terminated with newline. 813 * 814 */ 815 816 void qword_add(char **bpp, int *lp, char *str) 817 { 818 char *bp = *bpp; 819 int len = *lp; 820 char c; 821 822 if (len < 0) return; 823 824 while ((c=*str++) && len) 825 switch(c) { 826 case ' ': 827 case '\t': 828 case '\n': 829 case '\\': 830 if (len >= 4) { 831 *bp++ = '\\'; 832 *bp++ = '0' + ((c & 0300)>>6); 833 *bp++ = '0' + ((c & 0070)>>3); 834 *bp++ = '0' + ((c & 0007)>>0); 835 } 836 len -= 4; 837 break; 838 default: 839 *bp++ = c; 840 len--; 841 } 842 if (c || len <1) len = -1; 843 else { 844 *bp++ = ' '; 845 len--; 846 } 847 *bpp = bp; 848 *lp = len; 849 } 850 851 void qword_addhex(char **bpp, int *lp, char *buf, int blen) 852 { 853 char *bp = *bpp; 854 int len = *lp; 855 856 if (len < 0) return; 857 858 if (len > 2) { 859 *bp++ = '\\'; 860 *bp++ = 'x'; 861 len -= 2; 862 while (blen && len >= 2) { 863 unsigned char c = *buf++; 864 *bp++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1); 865 *bp++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1); 866 len -= 2; 867 blen--; 868 } 869 } 870 if (blen || len<1) len = -1; 871 else { 872 *bp++ = ' '; 873 len--; 874 } 875 *bpp = bp; 876 *lp = len; 877 } 878 879 static void warn_no_listener(struct cache_detail *detail) 880 { 881 if (detail->last_warn != detail->last_close) { 882 detail->last_warn = detail->last_close; 883 if (detail->warn_no_listener) 884 detail->warn_no_listener(detail); 885 } 886 } 887 888 /* 889 * register an upcall request to user-space. 890 * Each request is at most one page long. 891 */ 892 static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h) 893 { 894 895 char *buf; 896 struct cache_request *crq; 897 char *bp; 898 int len; 899 900 if (detail->cache_request == NULL) 901 return -EINVAL; 902 903 if (atomic_read(&detail->readers) == 0 && 904 detail->last_close < get_seconds() - 30) { 905 warn_no_listener(detail); 906 return -EINVAL; 907 } 908 909 buf = kmalloc(PAGE_SIZE, GFP_KERNEL); 910 if (!buf) 911 return -EAGAIN; 912 913 crq = kmalloc(sizeof (*crq), GFP_KERNEL); 914 if (!crq) { 915 kfree(buf); 916 return -EAGAIN; 917 } 918 919 bp = buf; len = PAGE_SIZE; 920 921 detail->cache_request(detail, h, &bp, &len); 922 923 if (len < 0) { 924 kfree(buf); 925 kfree(crq); 926 return -EAGAIN; 927 } 928 crq->q.reader = 0; 929 crq->item = cache_get(h); 930 crq->buf = buf; 931 crq->len = PAGE_SIZE - len; 932 crq->readers = 0; 933 spin_lock(&queue_lock); 934 list_add_tail(&crq->q.list, &detail->queue); 935 spin_unlock(&queue_lock); 936 wake_up(&queue_wait); 937 return 0; 938 } 939 940 /* 941 * parse a message from user-space and pass it 942 * to an appropriate cache 943 * Messages are, like requests, separated into fields by 944 * spaces and dequotes as \xHEXSTRING or embedded \nnn octal 945 * 946 * Message is 947 * reply cachename expiry key ... content.... 948 * 949 * key and content are both parsed by cache 950 */ 951 952 #define isodigit(c) (isdigit(c) && c <= '7') 953 int qword_get(char **bpp, char *dest, int bufsize) 954 { 955 /* return bytes copied, or -1 on error */ 956 char *bp = *bpp; 957 int len = 0; 958 959 while (*bp == ' ') bp++; 960 961 if (bp[0] == '\\' && bp[1] == 'x') { 962 /* HEX STRING */ 963 bp += 2; 964 while (isxdigit(bp[0]) && isxdigit(bp[1]) && len < bufsize) { 965 int byte = isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10; 966 bp++; 967 byte <<= 4; 968 byte |= isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10; 969 *dest++ = byte; 970 bp++; 971 len++; 972 } 973 } else { 974 /* text with \nnn octal quoting */ 975 while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) { 976 if (*bp == '\\' && 977 isodigit(bp[1]) && (bp[1] <= '3') && 978 isodigit(bp[2]) && 979 isodigit(bp[3])) { 980 int byte = (*++bp -'0'); 981 bp++; 982 byte = (byte << 3) | (*bp++ - '0'); 983 byte = (byte << 3) | (*bp++ - '0'); 984 *dest++ = byte; 985 len++; 986 } else { 987 *dest++ = *bp++; 988 len++; 989 } 990 } 991 } 992 993 if (*bp != ' ' && *bp != '\n' && *bp != '\0') 994 return -1; 995 while (*bp == ' ') bp++; 996 *bpp = bp; 997 *dest = '\0'; 998 return len; 999 } 1000 1001 1002 /* 1003 * support /proc/sunrpc/cache/$CACHENAME/content 1004 * as a seqfile. 1005 * We call ->cache_show passing NULL for the item to 1006 * get a header, then pass each real item in the cache 1007 */ 1008 1009 struct handle { 1010 struct cache_detail *cd; 1011 }; 1012 1013 static void *c_start(struct seq_file *m, loff_t *pos) 1014 { 1015 loff_t n = *pos; 1016 unsigned hash, entry; 1017 struct cache_head *ch; 1018 struct cache_detail *cd = ((struct handle*)m->private)->cd; 1019 1020 1021 read_lock(&cd->hash_lock); 1022 if (!n--) 1023 return SEQ_START_TOKEN; 1024 hash = n >> 32; 1025 entry = n & ((1LL<<32) - 1); 1026 1027 for (ch=cd->hash_table[hash]; ch; ch=ch->next) 1028 if (!entry--) 1029 return ch; 1030 n &= ~((1LL<<32) - 1); 1031 do { 1032 hash++; 1033 n += 1LL<<32; 1034 } while(hash < cd->hash_size && 1035 cd->hash_table[hash]==NULL); 1036 if (hash >= cd->hash_size) 1037 return NULL; 1038 *pos = n+1; 1039 return cd->hash_table[hash]; 1040 } 1041 1042 static void *c_next(struct seq_file *m, void *p, loff_t *pos) 1043 { 1044 struct cache_head *ch = p; 1045 int hash = (*pos >> 32); 1046 struct cache_detail *cd = ((struct handle*)m->private)->cd; 1047 1048 if (p == SEQ_START_TOKEN) 1049 hash = 0; 1050 else if (ch->next == NULL) { 1051 hash++; 1052 *pos += 1LL<<32; 1053 } else { 1054 ++*pos; 1055 return ch->next; 1056 } 1057 *pos &= ~((1LL<<32) - 1); 1058 while (hash < cd->hash_size && 1059 cd->hash_table[hash] == NULL) { 1060 hash++; 1061 *pos += 1LL<<32; 1062 } 1063 if (hash >= cd->hash_size) 1064 return NULL; 1065 ++*pos; 1066 return cd->hash_table[hash]; 1067 } 1068 1069 static void c_stop(struct seq_file *m, void *p) 1070 { 1071 struct cache_detail *cd = ((struct handle*)m->private)->cd; 1072 read_unlock(&cd->hash_lock); 1073 } 1074 1075 static int c_show(struct seq_file *m, void *p) 1076 { 1077 struct cache_head *cp = p; 1078 struct cache_detail *cd = ((struct handle*)m->private)->cd; 1079 1080 if (p == SEQ_START_TOKEN) 1081 return cd->cache_show(m, cd, NULL); 1082 1083 ifdebug(CACHE) 1084 seq_printf(m, "# expiry=%ld refcnt=%d\n", 1085 cp->expiry_time, atomic_read(&cp->refcnt)); 1086 cache_get(cp); 1087 if (cache_check(cd, cp, NULL)) 1088 /* cache_check does a cache_put on failure */ 1089 seq_printf(m, "# "); 1090 else 1091 cache_put(cp, cd); 1092 1093 return cd->cache_show(m, cd, cp); 1094 } 1095 1096 static struct seq_operations cache_content_op = { 1097 .start = c_start, 1098 .next = c_next, 1099 .stop = c_stop, 1100 .show = c_show, 1101 }; 1102 1103 static int content_open(struct inode *inode, struct file *file) 1104 { 1105 int res; 1106 struct handle *han; 1107 struct cache_detail *cd = PDE(inode)->data; 1108 1109 han = kmalloc(sizeof(*han), GFP_KERNEL); 1110 if (han == NULL) 1111 return -ENOMEM; 1112 1113 han->cd = cd; 1114 1115 res = seq_open(file, &cache_content_op); 1116 if (res) 1117 kfree(han); 1118 else 1119 ((struct seq_file *)file->private_data)->private = han; 1120 1121 return res; 1122 } 1123 static int content_release(struct inode *inode, struct file *file) 1124 { 1125 struct seq_file *m = (struct seq_file *)file->private_data; 1126 struct handle *han = m->private; 1127 kfree(han); 1128 m->private = NULL; 1129 return seq_release(inode, file); 1130 } 1131 1132 static struct file_operations content_file_operations = { 1133 .open = content_open, 1134 .read = seq_read, 1135 .llseek = seq_lseek, 1136 .release = content_release, 1137 }; 1138 1139 static ssize_t read_flush(struct file *file, char __user *buf, 1140 size_t count, loff_t *ppos) 1141 { 1142 struct cache_detail *cd = PDE(file->f_dentry->d_inode)->data; 1143 char tbuf[20]; 1144 unsigned long p = *ppos; 1145 int len; 1146 1147 sprintf(tbuf, "%lu\n", cd->flush_time); 1148 len = strlen(tbuf); 1149 if (p >= len) 1150 return 0; 1151 len -= p; 1152 if (len > count) len = count; 1153 if (copy_to_user(buf, (void*)(tbuf+p), len)) 1154 len = -EFAULT; 1155 else 1156 *ppos += len; 1157 return len; 1158 } 1159 1160 static ssize_t write_flush(struct file * file, const char __user * buf, 1161 size_t count, loff_t *ppos) 1162 { 1163 struct cache_detail *cd = PDE(file->f_dentry->d_inode)->data; 1164 char tbuf[20]; 1165 char *ep; 1166 long flushtime; 1167 if (*ppos || count > sizeof(tbuf)-1) 1168 return -EINVAL; 1169 if (copy_from_user(tbuf, buf, count)) 1170 return -EFAULT; 1171 tbuf[count] = 0; 1172 flushtime = simple_strtoul(tbuf, &ep, 0); 1173 if (*ep && *ep != '\n') 1174 return -EINVAL; 1175 1176 cd->flush_time = flushtime; 1177 cd->nextcheck = get_seconds(); 1178 cache_flush(); 1179 1180 *ppos += count; 1181 return count; 1182 } 1183 1184 static struct file_operations cache_flush_operations = { 1185 .open = nonseekable_open, 1186 .read = read_flush, 1187 .write = write_flush, 1188 }; 1189