diff options
Diffstat (limited to 'net/sunrpc/cache.c')
| -rw-r--r-- | net/sunrpc/cache.c | 1189 |
1 files changed, 1189 insertions, 0 deletions
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c new file mode 100644 index 000000000000..900f5bc7e336 --- /dev/null +++ b/net/sunrpc/cache.c @@ -0,0 +1,1189 @@ +/* + * 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 <asm/ioctls.h> +#include <linux/sunrpc/types.h> +#include <linux/sunrpc/cache.h> +#include <linux/sunrpc/stats.h> + +#define RPCDBG_FACILITY RPCDBG_CACHE + +static void cache_defer_req(struct cache_req *req, struct cache_head *item); +static void cache_revisit_request(struct cache_head *item); + +void cache_init(struct cache_head *h) +{ + time_t now = get_seconds(); + h->next = NULL; + h->flags = 0; + atomic_set(&h->refcnt, 1); + h->expiry_time = now + CACHE_NEW_EXPIRY; + h->last_refresh = now; +} + + +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, + * -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("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(detail, 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) + cache_defer_req(rqstp, h); + + if (rv && h) + detail->cache_put(h, detail); + return rv; +} + +static void queue_loose(struct cache_detail *detail, struct cache_head *ch); + +void cache_fresh(struct cache_detail *detail, + struct cache_head *head, time_t expiry) +{ + + head->expiry_time = expiry; + head->last_refresh = get_seconds(); + if (!test_and_set_bit(CACHE_VALID, &head->flags)) + cache_revisit_request(head); + if (test_and_clear_bit(CACHE_PENDING, &head->flags)) + queue_loose(detail, head); +} + +/* + * 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 struct file_operations cache_file_operations; +static struct file_operations content_file_operations; +static struct file_operations cache_flush_operations; + +static void do_cache_clean(void *data); +static DECLARE_WORK(cache_cleaner, do_cache_clean, NULL); + +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 = THIS_MODULE; + 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 = THIS_MODULE; + 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 = THIS_MODULE; + 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 = THIS_MODULE; + 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_work(&cache_cleaner); +} + +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(&cache_cleaner); + flush_scheduled_work(); + } + 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->refcnt) == 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) + d->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(void *data) +{ + 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 void cache_defer_req(struct cache_req *req, struct cache_head *item) +{ + struct cache_deferred_req *dreq; + int hash = DFR_HASH(item); + + dreq = req->defer(req); + if (dreq == NULL) + return; + + 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) { + /* too much in the cache, randomly drop + * first or last + */ + if (net_random()&1) + dreq = list_entry(cache_defer_list.next, + struct cache_deferred_req, + recent); + else + 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_VALID, &item->flags)) { + /* must have just been validated... */ + cache_revisit_request(item); + } +} + +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 DECLARE_MUTEX(queue_io_sem); + +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_dentry->d_inode)->data; + int err; + + if (count == 0) + return 0; + + down(&queue_io_sem); /* 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); + up(&queue_io_sem); + if (rp->offset) + BUG(); + return 0; + } + rq = container_of(rp->q.list.next, struct cache_request, q.list); + if (rq->q.reader) BUG(); + 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); + cd->cache_put(rq->item, cd); + kfree(rq->buf); + kfree(rq); + } else + spin_unlock(&queue_lock); + } + if (err == -EAGAIN) + goto again; + up(&queue_io_sem); + return err ? err : count; +} + +static char write_buf[8192]; /* protected by queue_io_sem */ + +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_dentry->d_inode)->data; + + if (count == 0) + return 0; + if (count >= sizeof(write_buf)) + return -EINVAL; + + down(&queue_io_sem); + + if (copy_from_user(write_buf, buf, count)) { + up(&queue_io_sem); + return -EFAULT; + } + write_buf[count] = '\0'; + if (cd->cache_parse) + err = cd->cache_parse(cd, write_buf, count); + else + err = -EINVAL; + + up(&queue_io_sem); + 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_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 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) + break; + list_del(&cr->q.list); + spin_unlock(&queue_lock); + detail->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) +{ + 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) +{ + 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\n", + cp->expiry_time, atomic_read(&cp->refcnt)); + 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 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) +{ + int res; + struct handle *han; + struct cache_detail *cd = PDE(inode)->data; + + han = kmalloc(sizeof(*han), GFP_KERNEL); + if (han == NULL) + return -ENOMEM; + + han->cd = cd; + + res = seq_open(file, &cache_content_op); + if (res) + kfree(han); + else + ((struct seq_file *)file->private_data)->private = han; + + return res; +} +static int content_release(struct inode *inode, struct file *file) +{ + struct seq_file *m = (struct seq_file *)file->private_data; + struct handle *han = m->private; + kfree(han); + m->private = NULL; + return seq_release(inode, file); +} + +static struct file_operations content_file_operations = { + .open = content_open, + .read = seq_read, + .llseek = seq_lseek, + .release = content_release, +}; + +static ssize_t read_flush(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + struct cache_detail *cd = PDE(file->f_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_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 struct file_operations cache_flush_operations = { + .open = nonseekable_open, + .read = read_flush, + .write = write_flush, +}; |