diff options
Diffstat (limited to 'drivers/xen/xenfs/xenbus.c')
| -rw-r--r-- | drivers/xen/xenfs/xenbus.c | 598 |
1 files changed, 0 insertions, 598 deletions
diff --git a/drivers/xen/xenfs/xenbus.c b/drivers/xen/xenfs/xenbus.c deleted file mode 100644 index 1c1236087f7..00000000000 --- a/drivers/xen/xenfs/xenbus.c +++ /dev/null @@ -1,598 +0,0 @@ -/* - * Driver giving user-space access to the kernel's xenbus connection - * to xenstore. - * - * Copyright (c) 2005, Christian Limpach - * Copyright (c) 2005, Rusty Russell, IBM Corporation - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License version 2 - * as published by the Free Software Foundation; or, when distributed - * separately from the Linux kernel or incorporated into other - * software packages, subject to the following license: - * - * Permission is hereby granted, free of charge, to any person obtaining a copy - * of this source file (the "Software"), to deal in the Software without - * restriction, including without limitation the rights to use, copy, modify, - * merge, publish, distribute, sublicense, and/or sell copies of the Software, - * and to permit persons to whom the Software is furnished to do so, subject to - * the following conditions: - * - * The above copyright notice and this permission notice shall be included in - * all copies or substantial portions of the Software. - * - * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR - * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE - * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER - * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING - * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS - * IN THE SOFTWARE. - * - * Changes: - * 2008-10-07 Alex Zeffertt Replaced /proc/xen/xenbus with xenfs filesystem - * and /proc/xen compatibility mount point. - * Turned xenfs into a loadable module. - */ - -#include <linux/kernel.h> -#include <linux/errno.h> -#include <linux/uio.h> -#include <linux/notifier.h> -#include <linux/wait.h> -#include <linux/fs.h> -#include <linux/poll.h> -#include <linux/mutex.h> -#include <linux/sched.h> -#include <linux/spinlock.h> -#include <linux/mount.h> -#include <linux/pagemap.h> -#include <linux/uaccess.h> -#include <linux/init.h> -#include <linux/namei.h> -#include <linux/string.h> -#include <linux/slab.h> - -#include "xenfs.h" -#include "../xenbus/xenbus_comms.h" - -#include <xen/xenbus.h> -#include <asm/xen/hypervisor.h> - -/* - * An element of a list of outstanding transactions, for which we're - * still waiting a reply. - */ -struct xenbus_transaction_holder { - struct list_head list; - struct xenbus_transaction handle; -}; - -/* - * A buffer of data on the queue. - */ -struct read_buffer { - struct list_head list; - unsigned int cons; - unsigned int len; - char msg[]; -}; - -struct xenbus_file_priv { - /* - * msgbuffer_mutex is held while partial requests are built up - * and complete requests are acted on. It therefore protects - * the "transactions" and "watches" lists, and the partial - * request length and buffer. - * - * reply_mutex protects the reply being built up to return to - * usermode. It nests inside msgbuffer_mutex but may be held - * alone during a watch callback. - */ - struct mutex msgbuffer_mutex; - - /* In-progress transactions */ - struct list_head transactions; - - /* Active watches. */ - struct list_head watches; - - /* Partial request. */ - unsigned int len; - union { - struct xsd_sockmsg msg; - char buffer[PAGE_SIZE]; - } u; - - /* Response queue. */ - struct mutex reply_mutex; - struct list_head read_buffers; - wait_queue_head_t read_waitq; - -}; - -/* Read out any raw xenbus messages queued up. */ -static ssize_t xenbus_file_read(struct file *filp, - char __user *ubuf, - size_t len, loff_t *ppos) -{ - struct xenbus_file_priv *u = filp->private_data; - struct read_buffer *rb; - unsigned i; - int ret; - - mutex_lock(&u->reply_mutex); - while (list_empty(&u->read_buffers)) { - mutex_unlock(&u->reply_mutex); - if (filp->f_flags & O_NONBLOCK) - return -EAGAIN; - - ret = wait_event_interruptible(u->read_waitq, - !list_empty(&u->read_buffers)); - if (ret) - return ret; - mutex_lock(&u->reply_mutex); - } - - rb = list_entry(u->read_buffers.next, struct read_buffer, list); - i = 0; - while (i < len) { - unsigned sz = min((unsigned)len - i, rb->len - rb->cons); - - ret = copy_to_user(ubuf + i, &rb->msg[rb->cons], sz); - - i += sz - ret; - rb->cons += sz - ret; - - if (ret != sz) { - if (i == 0) - i = -EFAULT; - goto out; - } - - /* Clear out buffer if it has been consumed */ - if (rb->cons == rb->len) { - list_del(&rb->list); - kfree(rb); - if (list_empty(&u->read_buffers)) - break; - rb = list_entry(u->read_buffers.next, - struct read_buffer, list); - } - } - -out: - mutex_unlock(&u->reply_mutex); - return i; -} - -/* - * Add a buffer to the queue. Caller must hold the appropriate lock - * if the queue is not local. (Commonly the caller will build up - * multiple queued buffers on a temporary local list, and then add it - * to the appropriate list under lock once all the buffers have een - * successfully allocated.) - */ -static int queue_reply(struct list_head *queue, const void *data, size_t len) -{ - struct read_buffer *rb; - - if (len == 0) - return 0; - - rb = kmalloc(sizeof(*rb) + len, GFP_KERNEL); - if (rb == NULL) - return -ENOMEM; - - rb->cons = 0; - rb->len = len; - - memcpy(rb->msg, data, len); - - list_add_tail(&rb->list, queue); - return 0; -} - -/* - * Free all the read_buffer s on a list. - * Caller must have sole reference to list. - */ -static void queue_cleanup(struct list_head *list) -{ - struct read_buffer *rb; - - while (!list_empty(list)) { - rb = list_entry(list->next, struct read_buffer, list); - list_del(list->next); - kfree(rb); - } -} - -struct watch_adapter { - struct list_head list; - struct xenbus_watch watch; - struct xenbus_file_priv *dev_data; - char *token; -}; - -static void free_watch_adapter(struct watch_adapter *watch) -{ - kfree(watch->watch.node); - kfree(watch->token); - kfree(watch); -} - -static struct watch_adapter *alloc_watch_adapter(const char *path, - const char *token) -{ - struct watch_adapter *watch; - - watch = kzalloc(sizeof(*watch), GFP_KERNEL); - if (watch == NULL) - goto out_fail; - - watch->watch.node = kstrdup(path, GFP_KERNEL); - if (watch->watch.node == NULL) - goto out_free; - - watch->token = kstrdup(token, GFP_KERNEL); - if (watch->token == NULL) - goto out_free; - - return watch; - -out_free: - free_watch_adapter(watch); - -out_fail: - return NULL; -} - -static void watch_fired(struct xenbus_watch *watch, - const char **vec, - unsigned int len) -{ - struct watch_adapter *adap; - struct xsd_sockmsg hdr; - const char *path, *token; - int path_len, tok_len, body_len, data_len = 0; - int ret; - LIST_HEAD(staging_q); - - adap = container_of(watch, struct watch_adapter, watch); - - path = vec[XS_WATCH_PATH]; - token = adap->token; - - path_len = strlen(path) + 1; - tok_len = strlen(token) + 1; - if (len > 2) - data_len = vec[len] - vec[2] + 1; - body_len = path_len + tok_len + data_len; - - hdr.type = XS_WATCH_EVENT; - hdr.len = body_len; - - mutex_lock(&adap->dev_data->reply_mutex); - - ret = queue_reply(&staging_q, &hdr, sizeof(hdr)); - if (!ret) - ret = queue_reply(&staging_q, path, path_len); - if (!ret) - ret = queue_reply(&staging_q, token, tok_len); - if (!ret && len > 2) - ret = queue_reply(&staging_q, vec[2], data_len); - - if (!ret) { - /* success: pass reply list onto watcher */ - list_splice_tail(&staging_q, &adap->dev_data->read_buffers); - wake_up(&adap->dev_data->read_waitq); - } else - queue_cleanup(&staging_q); - - mutex_unlock(&adap->dev_data->reply_mutex); -} - -static int xenbus_write_transaction(unsigned msg_type, - struct xenbus_file_priv *u) -{ - int rc; - void *reply; - struct xenbus_transaction_holder *trans = NULL; - LIST_HEAD(staging_q); - - if (msg_type == XS_TRANSACTION_START) { - trans = kmalloc(sizeof(*trans), GFP_KERNEL); - if (!trans) { - rc = -ENOMEM; - goto out; - } - } - - reply = xenbus_dev_request_and_reply(&u->u.msg); - if (IS_ERR(reply)) { - kfree(trans); - rc = PTR_ERR(reply); - goto out; - } - - if (msg_type == XS_TRANSACTION_START) { - trans->handle.id = simple_strtoul(reply, NULL, 0); - - list_add(&trans->list, &u->transactions); - } else if (msg_type == XS_TRANSACTION_END) { - list_for_each_entry(trans, &u->transactions, list) - if (trans->handle.id == u->u.msg.tx_id) - break; - BUG_ON(&trans->list == &u->transactions); - list_del(&trans->list); - - kfree(trans); - } - - mutex_lock(&u->reply_mutex); - rc = queue_reply(&staging_q, &u->u.msg, sizeof(u->u.msg)); - if (!rc) - rc = queue_reply(&staging_q, reply, u->u.msg.len); - if (!rc) { - list_splice_tail(&staging_q, &u->read_buffers); - wake_up(&u->read_waitq); - } else { - queue_cleanup(&staging_q); - } - mutex_unlock(&u->reply_mutex); - - kfree(reply); - -out: - return rc; -} - -static int xenbus_write_watch(unsigned msg_type, struct xenbus_file_priv *u) -{ - struct watch_adapter *watch, *tmp_watch; - char *path, *token; - int err, rc; - LIST_HEAD(staging_q); - - path = u->u.buffer + sizeof(u->u.msg); - token = memchr(path, 0, u->u.msg.len); - if (token == NULL) { - rc = -EILSEQ; - goto out; - } - token++; - - if (msg_type == XS_WATCH) { - watch = alloc_watch_adapter(path, token); - if (watch == NULL) { - rc = -ENOMEM; - goto out; - } - - watch->watch.callback = watch_fired; - watch->dev_data = u; - - err = register_xenbus_watch(&watch->watch); - if (err) { - free_watch_adapter(watch); - rc = err; - goto out; - } - list_add(&watch->list, &u->watches); - } else { - list_for_each_entry_safe(watch, tmp_watch, &u->watches, list) { - if (!strcmp(watch->token, token) && - !strcmp(watch->watch.node, path)) { - unregister_xenbus_watch(&watch->watch); - list_del(&watch->list); - free_watch_adapter(watch); - break; - } - } - } - - /* Success. Synthesize a reply to say all is OK. */ - { - struct { - struct xsd_sockmsg hdr; - char body[3]; - } __packed reply = { - { - .type = msg_type, - .len = sizeof(reply.body) - }, - "OK" - }; - - mutex_lock(&u->reply_mutex); - rc = queue_reply(&u->read_buffers, &reply, sizeof(reply)); - mutex_unlock(&u->reply_mutex); - } - -out: - return rc; -} - -static ssize_t xenbus_file_write(struct file *filp, - const char __user *ubuf, - size_t len, loff_t *ppos) -{ - struct xenbus_file_priv *u = filp->private_data; - uint32_t msg_type; - int rc = len; - int ret; - LIST_HEAD(staging_q); - - /* - * We're expecting usermode to be writing properly formed - * xenbus messages. If they write an incomplete message we - * buffer it up. Once it is complete, we act on it. - */ - - /* - * Make sure concurrent writers can't stomp all over each - * other's messages and make a mess of our partial message - * buffer. We don't make any attemppt to stop multiple - * writers from making a mess of each other's incomplete - * messages; we're just trying to guarantee our own internal - * consistency and make sure that single writes are handled - * atomically. - */ - mutex_lock(&u->msgbuffer_mutex); - - /* Get this out of the way early to avoid confusion */ - if (len == 0) - goto out; - - /* Can't write a xenbus message larger we can buffer */ - if ((len + u->len) > sizeof(u->u.buffer)) { - /* On error, dump existing buffer */ - u->len = 0; - rc = -EINVAL; - goto out; - } - - ret = copy_from_user(u->u.buffer + u->len, ubuf, len); - - if (ret == len) { - rc = -EFAULT; - goto out; - } - - /* Deal with a partial copy. */ - len -= ret; - rc = len; - - u->len += len; - - /* Return if we haven't got a full message yet */ - if (u->len < sizeof(u->u.msg)) - goto out; /* not even the header yet */ - - /* If we're expecting a message that's larger than we can - possibly send, dump what we have and return an error. */ - if ((sizeof(u->u.msg) + u->u.msg.len) > sizeof(u->u.buffer)) { - rc = -E2BIG; - u->len = 0; - goto out; - } - - if (u->len < (sizeof(u->u.msg) + u->u.msg.len)) - goto out; /* incomplete data portion */ - - /* - * OK, now we have a complete message. Do something with it. - */ - - msg_type = u->u.msg.type; - - switch (msg_type) { - case XS_TRANSACTION_START: - case XS_TRANSACTION_END: - case XS_DIRECTORY: - case XS_READ: - case XS_GET_PERMS: - case XS_RELEASE: - case XS_GET_DOMAIN_PATH: - case XS_WRITE: - case XS_MKDIR: - case XS_RM: - case XS_SET_PERMS: - /* Send out a transaction */ - ret = xenbus_write_transaction(msg_type, u); - break; - - case XS_WATCH: - case XS_UNWATCH: - /* (Un)Ask for some path to be watched for changes */ - ret = xenbus_write_watch(msg_type, u); - break; - - default: - ret = -EINVAL; - break; - } - if (ret != 0) - rc = ret; - - /* Buffered message consumed */ - u->len = 0; - - out: - mutex_unlock(&u->msgbuffer_mutex); - return rc; -} - -static int xenbus_file_open(struct inode *inode, struct file *filp) -{ - struct xenbus_file_priv *u; - - if (xen_store_evtchn == 0) - return -ENOENT; - - nonseekable_open(inode, filp); - - u = kzalloc(sizeof(*u), GFP_KERNEL); - if (u == NULL) - return -ENOMEM; - - INIT_LIST_HEAD(&u->transactions); - INIT_LIST_HEAD(&u->watches); - INIT_LIST_HEAD(&u->read_buffers); - init_waitqueue_head(&u->read_waitq); - - mutex_init(&u->reply_mutex); - mutex_init(&u->msgbuffer_mutex); - - filp->private_data = u; - - return 0; -} - -static int xenbus_file_release(struct inode *inode, struct file *filp) -{ - struct xenbus_file_priv *u = filp->private_data; - struct xenbus_transaction_holder *trans, *tmp; - struct watch_adapter *watch, *tmp_watch; - - /* - * No need for locking here because there are no other users, - * by definition. - */ - - list_for_each_entry_safe(trans, tmp, &u->transactions, list) { - xenbus_transaction_end(trans->handle, 1); - list_del(&trans->list); - kfree(trans); - } - - list_for_each_entry_safe(watch, tmp_watch, &u->watches, list) { - unregister_xenbus_watch(&watch->watch); - list_del(&watch->list); - free_watch_adapter(watch); - } - - kfree(u); - - return 0; -} - -static unsigned int xenbus_file_poll(struct file *file, poll_table *wait) -{ - struct xenbus_file_priv *u = file->private_data; - - poll_wait(file, &u->read_waitq, wait); - if (!list_empty(&u->read_buffers)) - return POLLIN | POLLRDNORM; - return 0; -} - -const struct file_operations xenbus_file_ops = { - .read = xenbus_file_read, - .write = xenbus_file_write, - .open = xenbus_file_open, - .release = xenbus_file_release, - .poll = xenbus_file_poll, - .llseek = no_llseek, -}; |