--- /dev/null
+/*
+ * xenbus_dev.c
+ *
+ * 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.
+ */
+
+#include <linux/config.h>
+#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 "xenbus_comms.h"
+
+#include <asm/uaccess.h>
+#include <asm/hypervisor.h>
+#include <xen/xenbus.h>
+#include <xen/xen_proc.h>
+#include <asm/hypervisor.h>
+
+struct xenbus_dev_transaction {
+ struct list_head list;
+ struct xenbus_transaction handle;
+};
+
+struct xenbus_dev_data {
+ /* In-progress transaction. */
+ 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. */
+#define MASK_READ_IDX(idx) ((idx)&(PAGE_SIZE-1))
+ char read_buffer[PAGE_SIZE];
+ unsigned int read_cons, read_prod;
+ wait_queue_head_t read_waitq;
+
+ struct mutex reply_mutex;
+};
+
+static struct proc_dir_entry *xenbus_dev_intf;
+
+static ssize_t xenbus_dev_read(struct file *filp,
+ char __user *ubuf,
+ size_t len, loff_t *ppos)
+{
+ struct xenbus_dev_data *u = filp->private_data;
+ int i;
+
+ if (wait_event_interruptible(u->read_waitq,
+ u->read_prod != u->read_cons))
+ return -EINTR;
+
+ for (i = 0; i < len; i++) {
+ if (u->read_cons == u->read_prod)
+ break;
+ put_user(u->read_buffer[MASK_READ_IDX(u->read_cons)], ubuf+i);
+ u->read_cons++;
+ }
+
+ return i;
+}
+
+static void queue_reply(struct xenbus_dev_data *u,
+ char *data, unsigned int len)
+{
+ int i;
+
+ mutex_lock(&u->reply_mutex);
+
+ for (i = 0; i < len; i++, u->read_prod++)
+ u->read_buffer[MASK_READ_IDX(u->read_prod)] = data[i];
+
+ BUG_ON((u->read_prod - u->read_cons) > sizeof(u->read_buffer));
+
+ mutex_unlock(&u->reply_mutex);
+
+ wake_up(&u->read_waitq);
+}
+
+struct watch_adapter
+{
+ struct list_head list;
+ struct xenbus_watch watch;
+ struct xenbus_dev_data *dev_data;
+ char *token;
+};
+
+static void free_watch_adapter (struct watch_adapter *watch)
+{
+ kfree(watch->watch.node);
+ kfree(watch->token);
+ kfree(watch);
+}
+
+static void watch_fired(struct xenbus_watch *watch,
+ const char **vec,
+ unsigned int len)
+{
+ struct watch_adapter *adap =
+ container_of(watch, struct watch_adapter, watch);
+ struct xsd_sockmsg hdr;
+ const char *path, *token;
+ int path_len, tok_len, body_len;
+
+ path = vec[XS_WATCH_PATH];
+ token = adap->token;
+
+ path_len = strlen(path) + 1;
+ tok_len = strlen(token) + 1;
+ body_len = path_len + tok_len;
+
+ hdr.type = XS_WATCH_EVENT;
+ hdr.len = body_len;
+
+ queue_reply(adap->dev_data, (char *)&hdr, sizeof(hdr));
+ queue_reply(adap->dev_data, (char *)path, path_len);
+ queue_reply(adap->dev_data, (char *)token, tok_len);
+}
+
+static LIST_HEAD(watch_list);
+
+static ssize_t xenbus_dev_write(struct file *filp,
+ const char __user *ubuf,
+ size_t len, loff_t *ppos)
+{
+ struct xenbus_dev_data *u = filp->private_data;
+ struct xenbus_dev_transaction *trans = NULL;
+ uint32_t msg_type;
+ void *reply;
+ char *path, *token;
+ struct watch_adapter *watch, *tmp_watch;
+ int err;
+
+ if ((len + u->len) > sizeof(u->u.buffer))
+ return -EINVAL;
+
+ if (copy_from_user(u->u.buffer + u->len, ubuf, len) != 0)
+ return -EFAULT;
+
+ u->len += len;
+ if (u->len < (sizeof(u->u.msg) + u->u.msg.len))
+ return len;
+
+ 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:
+ if (msg_type == XS_TRANSACTION_START) {
+ trans = kmalloc(sizeof(*trans), GFP_KERNEL);
+ if (!trans)
+ return -ENOMEM;
+ }
+
+ reply = xenbus_dev_request_and_reply(&u->u.msg);
+ if (IS_ERR(reply)) {
+ kfree(trans);
+ return PTR_ERR(reply);
+ }
+
+ 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);
+ }
+ queue_reply(u, (char *)&u->u.msg, sizeof(u->u.msg));
+ queue_reply(u, (char *)reply, u->u.msg.len);
+ kfree(reply);
+ break;
+
+ case XS_WATCH:
+ case XS_UNWATCH:
+ path = u->u.buffer + sizeof(u->u.msg);
+ token = memchr(path, 0, u->u.msg.len);
+ if (token == NULL)
+ return -EILSEQ;
+ token++;
+
+ if (msg_type == XS_WATCH) {
+ static const char * XS_WATCH_RESP = "OK";
+ struct xsd_sockmsg hdr;
+
+ watch = kmalloc(sizeof(*watch), GFP_KERNEL);
+ watch->watch.node = kmalloc(strlen(path)+1,
+ GFP_KERNEL);
+ strcpy((char *)watch->watch.node, path);
+ watch->watch.callback = watch_fired;
+ watch->token = kmalloc(strlen(token)+1, GFP_KERNEL);
+ strcpy(watch->token, token);
+ watch->dev_data = u;
+
+ err = register_xenbus_watch(&watch->watch);
+ if (err) {
+ free_watch_adapter(watch);
+ return err;
+ }
+
+ list_add(&watch->list, &u->watches);
+
+ hdr.type = XS_WATCH;
+ hdr.len = strlen(XS_WATCH_RESP) + 1;
+ queue_reply(u, (char *)&hdr, sizeof(hdr));
+ queue_reply(u, (char *)XS_WATCH_RESP, hdr.len);
+ } else {
+ list_for_each_entry_safe(watch, tmp_watch,
+ &u->watches, list) {
+ if (!strcmp(watch->token, token) &&
+ !strcmp(watch->watch.node, path))
+ break;
+ {
+ unregister_xenbus_watch(&watch->watch);
+ list_del(&watch->list);
+ free_watch_adapter(watch);
+ break;
+ }
+ }
+ }
+
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ u->len = 0;
+ return len;
+}
+
+static int xenbus_dev_open(struct inode *inode, struct file *filp)
+{
+ struct xenbus_dev_data *u;
+
+ if (xen_start_info->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_waitqueue_head(&u->read_waitq);
+
+ mutex_init(&u->reply_mutex);
+
+ filp->private_data = u;
+
+ return 0;
+}
+
+static int xenbus_dev_release(struct inode *inode, struct file *filp)
+{
+ struct xenbus_dev_data *u = filp->private_data;
+ struct xenbus_dev_transaction *trans, *tmp;
+ struct watch_adapter *watch, *tmp_watch;
+
+ 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_dev_poll(struct file *file, poll_table *wait)
+{
+ struct xenbus_dev_data *u = file->private_data;
+
+ poll_wait(file, &u->read_waitq, wait);
+ if (u->read_cons != u->read_prod)
+ return POLLIN | POLLRDNORM;
+ return 0;
+}
+
+static struct file_operations xenbus_dev_file_ops = {
+ .read = xenbus_dev_read,
+ .write = xenbus_dev_write,
+ .open = xenbus_dev_open,
+ .release = xenbus_dev_release,
+ .poll = xenbus_dev_poll,
+};
+
+static int __init
+xenbus_dev_init(void)
+{
+ xenbus_dev_intf = create_xen_proc_entry("xenbus", 0400);
+ if (xenbus_dev_intf)
+ xenbus_dev_intf->proc_fops = &xenbus_dev_file_ops;
+
+ return 0;
+}
+
+__initcall(xenbus_dev_init);
git://git.onelab.eu / linux-2.6.git / blobdiff