--- /dev/null
+/******************************************************************************
+ * Client-facing interface for the Xenbus driver. In other words, the
+ * interface between the Xenbus and the device-specific code, be it the
+ * frontend or the backend of that driver.
+ *
+ * Copyright (C) 2005 XenSource Ltd
+ *
+ * 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 <xen/evtchn.h>
+#include <xen/gnttab.h>
+#include <xen/xenbus.h>
+#include <xen/driver_util.h>
+
+/* xenbus_probe.c */
+extern char *kasprintf(const char *fmt, ...);
+
+#define DPRINTK(fmt, args...) \
+ pr_debug("xenbus_client (%s:%d) " fmt ".\n", __FUNCTION__, __LINE__, ##args)
+
+int xenbus_watch_path(struct xenbus_device *dev, const char *path,
+ struct xenbus_watch *watch,
+ void (*callback)(struct xenbus_watch *,
+ const char **, unsigned int))
+{
+ int err;
+
+ watch->node = path;
+ watch->callback = callback;
+
+ err = register_xenbus_watch(watch);
+
+ if (err) {
+ watch->node = NULL;
+ watch->callback = NULL;
+ xenbus_dev_fatal(dev, err, "adding watch on %s", path);
+ }
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_watch_path);
+
+
+int xenbus_watch_path2(struct xenbus_device *dev, const char *path,
+ const char *path2, struct xenbus_watch *watch,
+ void (*callback)(struct xenbus_watch *,
+ const char **, unsigned int))
+{
+ int err;
+ char *state = kasprintf("%s/%s", path, path2);
+ if (!state) {
+ xenbus_dev_fatal(dev, -ENOMEM, "allocating path for watch");
+ return -ENOMEM;
+ }
+ err = xenbus_watch_path(dev, state, watch, callback);
+
+ if (err)
+ kfree(state);
+ return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_watch_path2);
+
+
+int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state state)
+{
+ /* We check whether the state is currently set to the given value, and
+ if not, then the state is set. We don't want to unconditionally
+ write the given state, because we don't want to fire watches
+ unnecessarily. Furthermore, if the node has gone, we don't write
+ to it, as the device will be tearing down, and we don't want to
+ resurrect that directory.
+
+ Note that, because of this cached value of our state, this function
+ will not work inside a Xenstore transaction (something it was
+ trying to in the past) because dev->state would not get reset if
+ the transaction was aborted.
+
+ */
+
+ int current_state;
+ int err;
+
+ if (state == dev->state)
+ return 0;
+
+ err = xenbus_scanf(XBT_NIL, dev->nodename, "state", "%d",
+ ¤t_state);
+ if (err != 1)
+ return 0;
+
+ err = xenbus_printf(XBT_NIL, dev->nodename, "state", "%d", state);
+ if (err) {
+ if (state != XenbusStateClosing) /* Avoid looping */
+ xenbus_dev_fatal(dev, err, "writing new state");
+ return err;
+ }
+
+ dev->state = state;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(xenbus_switch_state);
+
+
+/**
+ * Return the path to the error node for the given device, or NULL on failure.
+ * If the value returned is non-NULL, then it is the caller's to kfree.
+ */
+static char *error_path(struct xenbus_device *dev)
+{
+ return kasprintf("error/%s", dev->nodename);
+}
+
+
+void _dev_error(struct xenbus_device *dev, int err, const char *fmt,
+ va_list ap)
+{
+ int ret;
+ unsigned int len;
+ char *printf_buffer = NULL, *path_buffer = NULL;
+
+#define PRINTF_BUFFER_SIZE 4096
+ printf_buffer = kmalloc(PRINTF_BUFFER_SIZE, GFP_KERNEL);
+ if (printf_buffer == NULL)
+ goto fail;
+
+ len = sprintf(printf_buffer, "%i ", -err);
+ ret = vsnprintf(printf_buffer+len, PRINTF_BUFFER_SIZE-len, fmt, ap);
+
+ BUG_ON(len + ret > PRINTF_BUFFER_SIZE-1);
+
+ dev_err(&dev->dev, "%s\n", printf_buffer);
+
+ path_buffer = error_path(dev);
+
+ if (path_buffer == NULL) {
+ printk("xenbus: failed to write error node for %s (%s)\n",
+ dev->nodename, printf_buffer);
+ goto fail;
+ }
+
+ if (xenbus_write(XBT_NIL, path_buffer, "error", printf_buffer) != 0) {
+ printk("xenbus: failed to write error node for %s (%s)\n",
+ dev->nodename, printf_buffer);
+ goto fail;
+ }
+
+fail:
+ if (printf_buffer)
+ kfree(printf_buffer);
+ if (path_buffer)
+ kfree(path_buffer);
+}
+
+
+void xenbus_dev_error(struct xenbus_device *dev, int err, const char *fmt,
+ ...)
+{
+ va_list ap;
+
+ va_start(ap, fmt);
+ _dev_error(dev, err, fmt, ap);
+ va_end(ap);
+}
+EXPORT_SYMBOL_GPL(xenbus_dev_error);
+
+
+void xenbus_dev_fatal(struct xenbus_device *dev, int err, const char *fmt,
+ ...)
+{
+ va_list ap;
+
+ va_start(ap, fmt);
+ _dev_error(dev, err, fmt, ap);
+ va_end(ap);
+
+ xenbus_switch_state(dev, XenbusStateClosing);
+}
+EXPORT_SYMBOL_GPL(xenbus_dev_fatal);
+
+
+int xenbus_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn)
+{
+ int err = gnttab_grant_foreign_access(dev->otherend_id, ring_mfn, 0);
+ if (err < 0)
+ xenbus_dev_fatal(dev, err, "granting access to ring page");
+ return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_grant_ring);
+
+
+int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port)
+{
+ struct evtchn_alloc_unbound alloc_unbound;
+ int err;
+
+ alloc_unbound.dom = DOMID_SELF;
+ alloc_unbound.remote_dom = dev->otherend_id;
+
+ err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
+ &alloc_unbound);
+ if (err)
+ xenbus_dev_fatal(dev, err, "allocating event channel");
+ else
+ *port = alloc_unbound.port;
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_alloc_evtchn);
+
+
+int xenbus_bind_evtchn(struct xenbus_device *dev, int remote_port, int *port)
+{
+ struct evtchn_bind_interdomain bind_interdomain;
+ int err;
+
+ bind_interdomain.remote_dom = dev->otherend_id;
+ bind_interdomain.remote_port = remote_port,
+
+ err = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain,
+ &bind_interdomain);
+ if (err)
+ xenbus_dev_fatal(dev, err,
+ "binding to event channel %d from domain %d",
+ remote_port, dev->otherend_id);
+ else
+ *port = bind_interdomain.local_port;
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(xenbus_bind_evtchn);
+
+
+int xenbus_free_evtchn(struct xenbus_device *dev, int port)
+{
+ struct evtchn_close close;
+ int err;
+
+ close.port = port;
+
+ err = HYPERVISOR_event_channel_op(EVTCHNOP_close, &close);
+ if (err)
+ xenbus_dev_error(dev, err, "freeing event channel %d", port);
+
+ return err;
+}
+
+
+enum xenbus_state xenbus_read_driver_state(const char *path)
+{
+ enum xenbus_state result;
+ int err = xenbus_gather(XBT_NIL, path, "state", "%d", &result, NULL);
+ if (err)
+ result = XenbusStateClosed;
+
+ return result;
+}
+EXPORT_SYMBOL_GPL(xenbus_read_driver_state);
git://git.onelab.eu / linux-2.6.git / blobdiff