/* * net/sunrpc/cache.c * * Generic code for various authentication-related caches * used by sunrpc clients and servers. * * Copyright (C) 2002 Neil Brown <neilb@cse.unsw.edu.au> * * Released under terms in GPL version 2. See COPYING. * */ #include <linux/types.h> #include <linux/fs.h> #include <linux/file.h> #include <linux/slab.h> #include <linux/signal.h> #include <linux/sched.h> #include <linux/kmod.h> #include <linux/list.h> #include <linux/module.h> #include <linux/ctype.h> #include <asm/uaccess.h> #include <linux/poll.h> #include <linux/seq_file.h> #include <linux/proc_fs.h> #include <linux/net.h> #include <linux/workqueue.h> #include <linux/mutex.h> #include <asm/ioctls.h> #include <linux/sunrpc/types.h> #include <linux/sunrpc/cache.h> #include <linux/sunrpc/stats.h> #define RPCDBG_FACILITY RPCDBG_CACHE static int cache_defer_req(struct cache_req *req, struct cache_head *item); static void cache_revisit_request(struct cache_head *item); static void cache_init(struct cache_head *h) { time_t now = get_seconds(); h->next = NULL; h->flags = 0; kref_init(&h->ref); h->expiry_time = now + CACHE_NEW_EXPIRY; h->last_refresh = now; } struct cache_head *sunrpc_cache_lookup(struct cache_detail *detail, struct cache_head *key, int hash) { struct cache_head **head, **hp; struct cache_head *new = NULL; head = &detail->hash_table[hash]; read_lock(&detail->hash_lock); for (hp=head; *hp != NULL ; hp = &(*hp)->next) { struct cache_head *tmp = *hp; if (detail->match(tmp, key)) { cache_get(tmp); read_unlock(&detail->hash_lock); return tmp; } } read_unlock(&detail->hash_lock); /* Didn't find anything, insert an empty entry */ new = detail->alloc(); if (!new) return NULL; /* must fully initialise 'new', else * we might get lose if we need to * cache_put it soon. */ cache_init(new); detail->init(new, key); write_lock(&detail->hash_lock); /* check if entry appeared while we slept */ for (hp=head; *hp != NULL ; hp = &(*hp)->next) { struct cache_head *tmp = *hp; if (detail->match(tmp, key)) { cache_get(tmp); write_unlock(&detail->hash_lock); cache_put(new, detail); return tmp; } } new->next = *head; *head = new; detail->entries++; cache_get(new); write_unlock(&detail->hash_lock); return new; } EXPORT_SYMBOL(sunrpc_cache_lookup); static void queue_loose(struct cache_detail *detail, struct cache_head *ch); static int cache_fresh_locked(struct cache_head *head, time_t expiry) { head->expiry_time = expiry; head->last_refresh = get_seconds(); return !test_and_set_bit(CACHE_VALID, &head->flags); } static void cache_fresh_unlocked(struct cache_head *head, struct cache_detail *detail, int new) { if (new) cache_revisit_request(head); if (test_and_clear_bit(CACHE_PENDING, &head->flags)) { cache_revisit_request(head); queue_loose(detail, head); } } struct cache_head *sunrpc_cache_update(struct cache_detail *detail, struct cache_head *new, struct cache_head *old, int hash) { /* The 'old' entry is to be replaced by 'new'. * If 'old' is not VALID, we update it directly, * otherwise we need to replace it */ struct cache_head **head; struct cache_head *tmp; int is_new; if (!test_bit(CACHE_VALID, &old->flags)) { write_lock(&detail->hash_lock); if (!test_bit(CACHE_VALID, &old->flags)) { if (test_bit(CACHE_NEGATIVE, &new->flags)) set_bit(CACHE_NEGATIVE, &old->flags); else detail->update(old, new); is_new = cache_fresh_locked(old, new->expiry_time); write_unlock(&detail->hash_lock); cache_fresh_unlocked(old, detail, is_new); return old; } write_unlock(&detail->hash_lock); } /* We need to insert a new entry */ tmp = detail->alloc(); if (!tmp) { cache_put(old, detail); return NULL; } cache_init(tmp); detail->init(tmp, old); head = &detail->hash_table[hash]; write_lock(&detail->hash_lock); if (test_bit(CACHE_NEGATIVE, &new->flags)) set_bit(CACHE_NEGATIVE, &tmp->flags); else detail->update(tmp, new); tmp->next = *head; *head = tmp; detail->entries++; cache_get(tmp); is_new = cache_fresh_locked(tmp, new->expiry_time); cache_fresh_locked(old, 0); write_unlock(&detail->hash_lock); cache_fresh_unlocked(tmp, detail, is_new); cache_fresh_unlocked(old, detail, 0); cache_put(old, detail); return tmp; } EXPORT_SYMBOL(sunrpc_cache_update); static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h); /* * This is the generic cache management routine for all * the authentication caches. * It checks the currency of a cache item and will (later) * initiate an upcall to fill it if needed. * * * Returns 0 if the cache_head can be used, or cache_puts it and returns * -EAGAIN if upcall is pending, * -ETIMEDOUT if upcall failed and should be retried, * -ENOENT if cache entry was negative */ int cache_check(struct cache_detail *detail, struct cache_head *h, struct cache_req *rqstp) { int rv; long refresh_age, age; /* First decide return status as best we can */ if (!test_bit(CACHE_VALID, &h->flags) || h->expiry_time < get_seconds()) rv = -EAGAIN; else if (detail->flush_time > h->last_refresh) rv = -EAGAIN; else { /* entry is valid */ if (test_bit(CACHE_NEGATIVE, &h->flags)) rv = -ENOENT; else rv = 0; } /* now see if we want to start an upcall */ refresh_age = (h->expiry_time - h->last_refresh); age = get_seconds() - h->last_refresh; if (rqstp == NULL) { if (rv == -EAGAIN) rv = -ENOENT; } else if (rv == -EAGAIN || age > refresh_age/2) { dprintk("RPC: Want update, refage=%ld, age=%ld\n", refresh_age, age); if (!test_and_set_bit(CACHE_PENDING, &h->flags)) { switch (cache_make_upcall(detail, h)) { case -EINVAL: clear_bit(CACHE_PENDING, &h->flags); if (rv == -EAGAIN) { set_bit(CACHE_NEGATIVE, &h->flags); cache_fresh_unlocked(h, detail, cache_fresh_locked(h, get_seconds()+CACHE_NEW_EXPIRY)); rv = -ENOENT; } break; case -EAGAIN: clear_bit(CACHE_PENDING, &h->flags); cache_revisit_request(h); break; } } } if (rv == -EAGAIN) if (cache_defer_req(rqstp, h) != 0) rv = -ETIMEDOUT; if (rv) cache_put(h, detail); return rv; } /* * caches need to be periodically cleaned. * For this we maintain a list of cache_detail and * a current pointer into that list and into the table * for that entry. * * Each time clean_cache is called it finds the next non-empty entry * in the current table and walks the list in that entry * looking for entries that can be removed. * * An entry gets removed if: * - The expiry is before current time * - The last_refresh time is before the flush_time for that cache * * later we might drop old entries with non-NEVER expiry if that table * is getting 'full' for some definition of 'full' * * The question of "how often to scan a table" is an interesting one * and is answered in part by the use of the "nextcheck" field in the * cache_detail. * When a scan of a table begins, the nextcheck field is set to a time * that is well into the future. * While scanning, if an expiry time is found that is earlier than the * current nextcheck time, nextcheck is set to that expiry time. * If the flush_time is ever set to a time earlier than the nextcheck * time, the nextcheck time is then set to that flush_time. * * A table is then only scanned if the current time is at least * the nextcheck time. * */ static LIST_HEAD(cache_list); static DEFINE_SPINLOCK(cache_list_lock); static struct cache_detail *current_detail; static int current_index; static const struct file_operations cache_file_operations; static const struct file_operations content_file_operations; static const struct file_operations cache_flush_operations; static void do_cache_clean(struct work_struct *work); static DECLARE_DELAYED_WORK(cache_cleaner, do_cache_clean); void cache_register(struct cache_detail *cd) { cd->proc_ent = proc_mkdir(cd->name, proc_net_rpc); if (cd->proc_ent) { struct proc_dir_entry *p; cd->proc_ent->owner = cd->owner; cd->channel_ent = cd->content_ent = NULL; p = create_proc_entry("flush", S_IFREG|S_IRUSR|S_IWUSR, cd->proc_ent); cd->flush_ent = p; if (p) { p->proc_fops = &cache_flush_operations; p->owner = cd->owner; p->data = cd; } if (cd->cache_request || cd->cache_parse) { p = create_proc_entry("channel", S_IFREG|S_IRUSR|S_IWUSR, cd->proc_ent); cd->channel_ent = p; if (p) { p->proc_fops = &cache_file_operations; p->owner = cd->owner; p->data = cd; } } if (cd->cache_show) { p = create_proc_entry("content", S_IFREG|S_IRUSR|S_IWUSR, cd->proc_ent); cd->content_ent = p; if (p) { p->proc_fops = &content_file_operations; p->owner = cd->owner; p->data = cd; } } } rwlock_init(&cd->hash_lock); INIT_LIST_HEAD(&cd->queue); spin_lock(&cache_list_lock); cd->nextcheck = 0; cd->entries = 0; atomic_set(&cd->readers, 0); cd->last_close = 0; cd->last_warn = -1; list_add(&cd->others, &cache_list); spin_unlock(&cache_list_lock); /* start the cleaning process */ schedule_delayed_work(&cache_cleaner, 0); } int cache_unregister(struct cache_detail *cd) { cache_purge(cd); spin_lock(&cache_list_lock); write_lock(&cd->hash_lock); if (cd->entries || atomic_read(&cd->inuse)) { write_unlock(&cd->hash_lock); spin_unlock(&cache_list_lock); return -EBUSY; } if (current_detail == cd) current_detail = NULL; list_del_init(&cd->others); write_unlock(&cd->hash_lock); spin_unlock(&cache_list_lock); if (cd->proc_ent) { if (cd->flush_ent) remove_proc_entry("flush", cd->proc_ent); if (cd->channel_ent) remove_proc_entry("channel", cd->proc_ent); if (cd->content_ent) remove_proc_entry("content", cd->proc_ent); cd->proc_ent = NULL; remove_proc_entry(cd->name, proc_net_rpc); } if (list_empty(&cache_list)) { /* module must be being unloaded so its safe to kill the worker */ cancel_delayed_work_sync(&cache_cleaner); } return 0; } /* clean cache tries to find something to clean * and cleans it. * It returns 1 if it cleaned something, * 0 if it didn't find anything this time * -1 if it fell off the end of the list. */ static int cache_clean(void) { int rv = 0; struct list_head *next; spin_lock(&cache_list_lock); /* find a suitable table if we don't already have one */ while (current_detail == NULL || current_index >= current_detail->hash_size) { if (current_detail) next = current_detail->others.next; else next = cache_list.next; if (next == &cache_list) { current_detail = NULL; spin_unlock(&cache_list_lock); return -1; } current_detail = list_entry(next, struct cache_detail, others); if (current_detail->nextcheck > get_seconds()) current_index = current_detail->hash_size; else { current_index = 0; current_detail->nextcheck = get_seconds()+30*60; } } /* find a non-empty bucket in the table */ while (current_detail && current_index < current_detail->hash_size && current_detail->hash_table[current_index] == NULL) current_index++; /* find a cleanable entry in the bucket and clean it, or set to next bucket */ if (current_detail && current_index < current_detail->hash_size) { struct cache_head *ch, **cp; struct cache_detail *d; write_lock(¤t_detail->hash_lock); /* Ok, now to clean this strand */ cp = & current_detail->hash_table[current_index]; ch = *cp; for (; ch; cp= & ch->next, ch= *cp) { if (current_detail->nextcheck > ch->expiry_time) current_detail->nextcheck = ch->expiry_time+1; if (ch->expiry_time >= get_seconds() && ch->last_refresh >= current_detail->flush_time ) continue; if (test_and_clear_bit(CACHE_PENDING, &ch->flags)) queue_loose(current_detail, ch); if (atomic_read(&ch->ref.refcount) == 1) break; } if (ch) { *cp = ch->next; ch->next = NULL; current_detail->entries--; rv = 1; } write_unlock(¤t_detail->hash_lock); d = current_detail; if (!ch) current_index ++; spin_unlock(&cache_list_lock); if (ch) cache_put(ch, d); } else spin_unlock(&cache_list_lock); return rv; } /* * We want to regularly clean the cache, so we need to schedule some work ... */ static void do_cache_clean(struct work_struct *work) { int delay = 5; if (cache_clean() == -1) delay = 30*HZ; if (list_empty(&cache_list)) delay = 0; if (delay) schedule_delayed_work(&cache_cleaner, delay); } /* * Clean all caches promptly. This just calls cache_clean * repeatedly until we are sure that every cache has had a chance to * be fully cleaned */ void cache_flush(void) { while (cache_clean() != -1) cond_resched(); while (cache_clean() != -1) cond_resched(); } void cache_purge(struct cache_detail *detail) { detail->flush_time = LONG_MAX; detail->nextcheck = get_seconds(); cache_flush(); detail->flush_time = 1; } /* * Deferral and Revisiting of Requests. * * If a cache lookup finds a pending entry, we * need to defer the request and revisit it later. * All deferred requests are stored in a hash table, * indexed by "struct cache_head *". * As it may be wasteful to store a whole request * structure, we allow the request to provide a * deferred form, which must contain a * 'struct cache_deferred_req' * This cache_deferred_req contains a method to allow * it to be revisited when cache info is available */ #define DFR_HASHSIZE (PAGE_SIZE/sizeof(struct list_head)) #define DFR_HASH(item) ((((long)item)>>4 ^ (((long)item)>>13)) % DFR_HASHSIZE) #define DFR_MAX 300 /* ??? */ static DEFINE_SPINLOCK(cache_defer_lock); static LIST_HEAD(cache_defer_list); static struct list_head cache_defer_hash[DFR_HASHSIZE]; static int cache_defer_cnt; static int cache_defer_req(struct cache_req *req, struct cache_head *item) { struct cache_deferred_req *dreq; int hash = DFR_HASH(item); if (cache_defer_cnt >= DFR_MAX) { /* too much in the cache, randomly drop this one, * or continue and drop the oldest below */ if (net_random()&1) return -ETIMEDOUT; } dreq = req->defer(req); if (dreq == NULL) return -ETIMEDOUT; dreq->item = item; dreq->recv_time = get_seconds(); spin_lock(&cache_defer_lock); list_add(&dreq->recent, &cache_defer_list); if (cache_defer_hash[hash].next == NULL) INIT_LIST_HEAD(&cache_defer_hash[hash]); list_add(&dreq->hash, &cache_defer_hash[hash]); /* it is in, now maybe clean up */ dreq = NULL; if (++cache_defer_cnt > DFR_MAX) { dreq = list_entry(cache_defer_list.prev, struct cache_deferred_req, recent); list_del(&dreq->recent); list_del(&dreq->hash); cache_defer_cnt--; } spin_unlock(&cache_defer_lock); if (dreq) { /* there was one too many */ dreq->revisit(dreq, 1); } if (!test_bit(CACHE_PENDING, &item->flags)) { /* must have just been validated... */ cache_revisit_request(item); } return 0; } static void cache_revisit_request(struct cache_head *item) { struct cache_deferred_req *dreq; struct list_head pending; struct list_head *lp; int hash = DFR_HASH(item); INIT_LIST_HEAD(&pending); spin_lock(&cache_defer_lock); lp = cache_defer_hash[hash].next; if (lp) { while (lp != &cache_defer_hash[hash]) { dreq = list_entry(lp, struct cache_deferred_req, hash); lp = lp->next; if (dreq->item == item) { list_del(&dreq->hash); list_move(&dreq->recent, &pending); cache_defer_cnt--; } } } spin_unlock(&cache_defer_lock); while (!list_empty(&pending)) { dreq = list_entry(pending.next, struct cache_deferred_req, recent); list_del_init(&dreq->recent); dreq->revisit(dreq, 0); } } void cache_clean_deferred(void *owner) { struct cache_deferred_req *dreq, *tmp; struct list_head pending; INIT_LIST_HEAD(&pending); spin_lock(&cache_defer_lock); list_for_each_entry_safe(dreq, tmp, &cache_defer_list, recent) { if (dreq->owner == owner) { list_del(&dreq->hash); list_move(&dreq->recent, &pending); cache_defer_cnt--; } } spin_unlock(&cache_defer_lock); while (!list_empty(&pending)) { dreq = list_entry(pending.next, struct cache_deferred_req, recent); list_del_init(&dreq->recent); dreq->revisit(dreq, 1); } } /* * communicate with user-space * * We have a magic /proc file - /proc/sunrpc/cache * On read, you get a full request, or block * On write, an update request is processed * Poll works if anything to read, and always allows write * * Implemented by linked list of requests. Each open file has * a ->private that also exists in this list. New request are added * to the end and may wakeup and preceding readers. * New readers are added to the head. If, on read, an item is found with * CACHE_UPCALLING clear, we free it from the list. * */ static DEFINE_SPINLOCK(queue_lock); static DEFINE_MUTEX(queue_io_mutex); struct cache_queue { struct list_head list; int reader; /* if 0, then request */ }; struct cache_request { struct cache_queue q; struct cache_head *item; char * buf; int len; int readers; }; struct cache_reader { struct cache_queue q; int offset; /* if non-0, we have a refcnt on next request */ }; static ssize_t cache_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) { struct cache_reader *rp = filp->private_data; struct cache_request *rq; struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data; int err; if (count == 0) return 0; mutex_lock(&queue_io_mutex); /* protect against multiple concurrent * readers on this file */ again: spin_lock(&queue_lock); /* need to find next request */ while (rp->q.list.next != &cd->queue && list_entry(rp->q.list.next, struct cache_queue, list) ->reader) { struct list_head *next = rp->q.list.next; list_move(&rp->q.list, next); } if (rp->q.list.next == &cd->queue) { spin_unlock(&queue_lock); mutex_unlock(&queue_io_mutex); BUG_ON(rp->offset); return 0; } rq = container_of(rp->q.list.next, struct cache_request, q.list); BUG_ON(rq->q.reader); if (rp->offset == 0) rq->readers++; spin_unlock(&queue_lock); if (rp->offset == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) { err = -EAGAIN; spin_lock(&queue_lock); list_move(&rp->q.list, &rq->q.list); spin_unlock(&queue_lock); } else { if (rp->offset + count > rq->len) count = rq->len - rp->offset; err = -EFAULT; if (copy_to_user(buf, rq->buf + rp->offset, count)) goto out; rp->offset += count; if (rp->offset >= rq->len) { rp->offset = 0; spin_lock(&queue_lock); list_move(&rp->q.list, &rq->q.list); spin_unlock(&queue_lock); } err = 0; } out: if (rp->offset == 0) { /* need to release rq */ spin_lock(&queue_lock); rq->readers--; if (rq->readers == 0 && !test_bit(CACHE_PENDING, &rq->item->flags)) { list_del(&rq->q.list); spin_unlock(&queue_lock); cache_put(rq->item, cd); kfree(rq->buf); kfree(rq); } else spin_unlock(&queue_lock); } if (err == -EAGAIN) goto again; mutex_unlock(&queue_io_mutex); return err ? err : count; } static char write_buf[8192]; /* protected by queue_io_mutex */ static ssize_t cache_write(struct file *filp, const char __user *buf, size_t count, loff_t *ppos) { int err; struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data; if (count == 0) return 0; if (count >= sizeof(write_buf)) return -EINVAL; mutex_lock(&queue_io_mutex); if (copy_from_user(write_buf, buf, count)) { mutex_unlock(&queue_io_mutex); return -EFAULT; } write_buf[count] = '\0'; if (cd->cache_parse) err = cd->cache_parse(cd, write_buf, count); else err = -EINVAL; mutex_unlock(&queue_io_mutex); return err ? err : count; } static DECLARE_WAIT_QUEUE_HEAD(queue_wait); static unsigned int cache_poll(struct file *filp, poll_table *wait) { unsigned int mask; struct cache_reader *rp = filp->private_data; struct cache_queue *cq; struct cache_detail *cd = PDE(filp->f_path.dentry->d_inode)->data; poll_wait(filp, &queue_wait, wait); /* alway allow write */ mask = POLL_OUT | POLLWRNORM; if (!rp) return mask; spin_lock(&queue_lock); for (cq= &rp->q; &cq->list != &cd->queue; cq = list_entry(cq->list.next, struct cache_queue, list)) if (!cq->reader) { mask |= POLLIN | POLLRDNORM; break; } spin_unlock(&queue_lock); return mask; } static int cache_ioctl(struct inode *ino, struct file *filp, unsigned int cmd, unsigned long arg) { int len = 0; struct cache_reader *rp = filp->private_data; struct cache_queue *cq; struct cache_detail *cd = PDE(ino)->data; if (cmd != FIONREAD || !rp) return -EINVAL; spin_lock(&queue_lock); /* only find the length remaining in current request, * or the length of the next request */ for (cq= &rp->q; &cq->list != &cd->queue; cq = list_entry(cq->list.next, struct cache_queue, list)) if (!cq->reader) { struct cache_request *cr = container_of(cq, struct cache_request, q); len = cr->len - rp->offset; break; } spin_unlock(&queue_lock); return put_user(len, (int __user *)arg); } static int cache_open(struct inode *inode, struct file *filp) { struct cache_reader *rp = NULL; nonseekable_open(inode, filp); if (filp->f_mode & FMODE_READ) { struct cache_detail *cd = PDE(inode)->data; rp = kmalloc(sizeof(*rp), GFP_KERNEL); if (!rp) return -ENOMEM; rp->offset = 0; rp->q.reader = 1; atomic_inc(&cd->readers); spin_lock(&queue_lock); list_add(&rp->q.list, &cd->queue); spin_unlock(&queue_lock); } filp->private_data = rp; return 0; } static int cache_release(struct inode *inode, struct file *filp) { struct cache_reader *rp = filp->private_data; struct cache_detail *cd = PDE(inode)->data; if (rp) { spin_lock(&queue_lock); if (rp->offset) { struct cache_queue *cq; for (cq= &rp->q; &cq->list != &cd->queue; cq = list_entry(cq->list.next, struct cache_queue, list)) if (!cq->reader) { container_of(cq, struct cache_request, q) ->readers--; break; } rp->offset = 0; } list_del(&rp->q.list); spin_unlock(&queue_lock); filp->private_data = NULL; kfree(rp); cd->last_close = get_seconds(); atomic_dec(&cd->readers); } return 0; } static const struct file_operations cache_file_operations = { .owner = THIS_MODULE, .llseek = no_llseek, .read = cache_read, .write = cache_write, .poll = cache_poll, .ioctl = cache_ioctl, /* for FIONREAD */ .open = cache_open, .release = cache_release, }; static void queue_loose(struct cache_detail *detail, struct cache_head *ch) { struct cache_queue *cq; spin_lock(&queue_lock); list_for_each_entry(cq, &detail->queue, list) if (!cq->reader) { struct cache_request *cr = container_of(cq, struct cache_request, q); if (cr->item != ch) continue; if (cr->readers != 0) continue; list_del(&cr->q.list); spin_unlock(&queue_lock); cache_put(cr->item, detail); kfree(cr->buf); kfree(cr); return; } spin_unlock(&queue_lock); } /* * Support routines for text-based upcalls. * Fields are separated by spaces. * Fields are either mangled to quote space tab newline slosh with slosh * or a hexified with a leading \x * Record is terminated with newline. * */ void qword_add(char **bpp, int *lp, char *str) { char *bp = *bpp; int len = *lp; char c; if (len < 0) return; while ((c=*str++) && len) switch(c) { case ' ': case '\t': case '\n': case '\\': if (len >= 4) { *bp++ = '\\'; *bp++ = '0' + ((c & 0300)>>6); *bp++ = '0' + ((c & 0070)>>3); *bp++ = '0' + ((c & 0007)>>0); } len -= 4; break; default: *bp++ = c; len--; } if (c || len <1) len = -1; else { *bp++ = ' '; len--; } *bpp = bp; *lp = len; } void qword_addhex(char **bpp, int *lp, char *buf, int blen) { char *bp = *bpp; int len = *lp; if (len < 0) return; if (len > 2) { *bp++ = '\\'; *bp++ = 'x'; len -= 2; while (blen && len >= 2) { unsigned char c = *buf++; *bp++ = '0' + ((c&0xf0)>>4) + (c>=0xa0)*('a'-'9'-1); *bp++ = '0' + (c&0x0f) + ((c&0x0f)>=0x0a)*('a'-'9'-1); len -= 2; blen--; } } if (blen || len<1) len = -1; else { *bp++ = ' '; len--; } *bpp = bp; *lp = len; } static void warn_no_listener(struct cache_detail *detail) { if (detail->last_warn != detail->last_close) { detail->last_warn = detail->last_close; if (detail->warn_no_listener) detail->warn_no_listener(detail); } } /* * register an upcall request to user-space. * Each request is at most one page long. */ static int cache_make_upcall(struct cache_detail *detail, struct cache_head *h) { char *buf; struct cache_request *crq; char *bp; int len; if (detail->cache_request == NULL) return -EINVAL; if (atomic_read(&detail->readers) == 0 && detail->last_close < get_seconds() - 30) { warn_no_listener(detail); return -EINVAL; } buf = kmalloc(PAGE_SIZE, GFP_KERNEL); if (!buf) return -EAGAIN; crq = kmalloc(sizeof (*crq), GFP_KERNEL); if (!crq) { kfree(buf); return -EAGAIN; } bp = buf; len = PAGE_SIZE; detail->cache_request(detail, h, &bp, &len); if (len < 0) { kfree(buf); kfree(crq); return -EAGAIN; } crq->q.reader = 0; crq->item = cache_get(h); crq->buf = buf; crq->len = PAGE_SIZE - len; crq->readers = 0; spin_lock(&queue_lock); list_add_tail(&crq->q.list, &detail->queue); spin_unlock(&queue_lock); wake_up(&queue_wait); return 0; } /* * parse a message from user-space and pass it * to an appropriate cache * Messages are, like requests, separated into fields by * spaces and dequotes as \xHEXSTRING or embedded \nnn octal * * Message is * reply cachename expiry key ... content.... * * key and content are both parsed by cache */ #define isodigit(c) (isdigit(c) && c <= '7') int qword_get(char **bpp, char *dest, int bufsize) { /* return bytes copied, or -1 on error */ char *bp = *bpp; int len = 0; while (*bp == ' ') bp++; if (bp[0] == '\\' && bp[1] == 'x') { /* HEX STRING */ bp += 2; while (isxdigit(bp[0]) && isxdigit(bp[1]) && len < bufsize) { int byte = isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10; bp++; byte <<= 4; byte |= isdigit(*bp) ? *bp-'0' : toupper(*bp)-'A'+10; *dest++ = byte; bp++; len++; } } else { /* text with \nnn octal quoting */ while (*bp != ' ' && *bp != '\n' && *bp && len < bufsize-1) { if (*bp == '\\' && isodigit(bp[1]) && (bp[1] <= '3') && isodigit(bp[2]) && isodigit(bp[3])) { int byte = (*++bp -'0'); bp++; byte = (byte << 3) | (*bp++ - '0'); byte = (byte << 3) | (*bp++ - '0'); *dest++ = byte; len++; } else { *dest++ = *bp++; len++; } } } if (*bp != ' ' && *bp != '\n' && *bp != '\0') return -1; while (*bp == ' ') bp++; *bpp = bp; *dest = '\0'; return len; } /* * support /proc/sunrpc/cache/$CACHENAME/content * as a seqfile. * We call ->cache_show passing NULL for the item to * get a header, then pass each real item in the cache */ struct handle { struct cache_detail *cd; }; static void *c_start(struct seq_file *m, loff_t *pos) __acquires(cd->hash_lock) { loff_t n = *pos; unsigned hash, entry; struct cache_head *ch; struct cache_detail *cd = ((struct handle*)m->private)->cd; read_lock(&cd->hash_lock); if (!n--) return SEQ_START_TOKEN; hash = n >> 32; entry = n & ((1LL<<32) - 1); for (ch=cd->hash_table[hash]; ch; ch=ch->next) if (!entry--) return ch; n &= ~((1LL<<32) - 1); do { hash++; n += 1LL<<32; } while(hash < cd->hash_size && cd->hash_table[hash]==NULL); if (hash >= cd->hash_size) return NULL; *pos = n+1; return cd->hash_table[hash]; } static void *c_next(struct seq_file *m, void *p, loff_t *pos) { struct cache_head *ch = p; int hash = (*pos >> 32); struct cache_detail *cd = ((struct handle*)m->private)->cd; if (p == SEQ_START_TOKEN) hash = 0; else if (ch->next == NULL) { hash++; *pos += 1LL<<32; } else { ++*pos; return ch->next; } *pos &= ~((1LL<<32) - 1); while (hash < cd->hash_size && cd->hash_table[hash] == NULL) { hash++; *pos += 1LL<<32; } if (hash >= cd->hash_size) return NULL; ++*pos; return cd->hash_table[hash]; } static void c_stop(struct seq_file *m, void *p) __releases(cd->hash_lock) { struct cache_detail *cd = ((struct handle*)m->private)->cd; read_unlock(&cd->hash_lock); } static int c_show(struct seq_file *m, void *p) { struct cache_head *cp = p; struct cache_detail *cd = ((struct handle*)m->private)->cd; if (p == SEQ_START_TOKEN) return cd->cache_show(m, cd, NULL); ifdebug(CACHE) seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n", cp->expiry_time, atomic_read(&cp->ref.refcount), cp->flags); cache_get(cp); if (cache_check(cd, cp, NULL)) /* cache_check does a cache_put on failure */ seq_printf(m, "# "); else cache_put(cp, cd); return cd->cache_show(m, cd, cp); } static const struct seq_operations cache_content_op = { .start = c_start, .next = c_next, .stop = c_stop, .show = c_show, }; static int content_open(struct inode *inode, struct file *file) { struct handle *han; struct cache_detail *cd = PDE(inode)->data; han = __seq_open_private(file, &cache_content_op, sizeof(*han)); if (han == NULL) return -ENOMEM; han->cd = cd; return 0; } static const struct file_operations content_file_operations = { .open = content_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release_private, }; static ssize_t read_flush(struct file *file, char __user *buf, size_t count, loff_t *ppos) { struct cache_detail *cd = PDE(file->f_path.dentry->d_inode)->data; char tbuf[20]; unsigned long p = *ppos; int len; sprintf(tbuf, "%lu\n", cd->flush_time); len = strlen(tbuf); if (p >= len) return 0; len -= p; if (len > count) len = count; if (copy_to_user(buf, (void*)(tbuf+p), len)) len = -EFAULT; else *ppos += len; return len; } static ssize_t write_flush(struct file * file, const char __user * buf, size_t count, loff_t *ppos) { struct cache_detail *cd = PDE(file->f_path.dentry->d_inode)->data; char tbuf[20]; char *ep; long flushtime; if (*ppos || count > sizeof(tbuf)-1) return -EINVAL; if (copy_from_user(tbuf, buf, count)) return -EFAULT; tbuf[count] = 0; flushtime = simple_strtoul(tbuf, &ep, 0); if (*ep && *ep != '\n') return -EINVAL; cd->flush_time = flushtime; cd->nextcheck = get_seconds(); cache_flush(); *ppos += count; return count; } static const struct file_operations cache_flush_operations = { .open = nonseekable_open, .read = read_flush, .write = write_flush, };