1 /******************************************************************************
2 * Copyright (C) 2005 Rusty Russell, IBM Corporation
3 * Copyright (C) 2005 XenSource Ltd.
4 *
5 * This file may be distributed separately from the Linux kernel, or
6 * incorporated into other software packages, subject to the following license:
7 *
8 * Permission is hereby granted, free of charge, to any person obtaining a copy
9 * of this source file (the "Software"), to deal in the Software without
10 * restriction, including without limitation the rights to use, copy, modify,
11 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
12 * and to permit persons to whom the Software is furnished to do so, subject to
13 * the following conditions:
14 *
15 * The above copyright notice and this permission notice shall be included in
16 * all copies or substantial portions of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
21 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
23 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
24 * IN THE SOFTWARE.
25 */
26
27 /**
28 * \file xenbusvar.h
29 *
30 * \brief Datastructures and function declarations for usedby device
31 * drivers operating on the XenBus.
32 */
33
34 #ifndef _XEN_XENBUS_XENBUSVAR_H
35 #define _XEN_XENBUS_XENBUSVAR_H
36
37 #include <sys/queue.h>
38 #include <sys/bus.h>
39 #include <sys/eventhandler.h>
40 #include <sys/malloc.h>
41 #include <sys/sbuf.h>
42 #include <sys/stdarg.h>
43
44 #include <xen/xen-os.h>
45 #include <contrib/xen/grant_table.h>
46 #include <contrib/xen/io/xenbus.h>
47 #include <contrib/xen/io/xs_wire.h>
48
49 #include <xen/xenstore/xenstorevar.h>
50
51 /* XenBus allocations including XenStore data returned to clients. */
52 MALLOC_DECLARE(M_XENBUS);
53
54 enum {
55 /**
56 * Path of this device node.
57 */
58 XENBUS_IVAR_NODE,
59
60 /**
61 * The device type (e.g. vif, vbd).
62 */
63 XENBUS_IVAR_TYPE,
64
65 /**
66 * The state of this device (not the otherend's state).
67 */
68 XENBUS_IVAR_STATE,
69
70 /**
71 * Domain ID of the other end device.
72 */
73 XENBUS_IVAR_OTHEREND_ID,
74
75 /**
76 * Path of the other end device.
77 */
78 XENBUS_IVAR_OTHEREND_PATH
79 };
80
81 /**
82 * Simplified accessors for xenbus devices:
83 *
84 * xenbus_get_node
85 * xenbus_get_type
86 * xenbus_get_state
87 * xenbus_get_otherend_id
88 * xenbus_get_otherend_path
89 */
90 #define XENBUS_ACCESSOR(var, ivar, type) \
91 __BUS_ACCESSOR(xenbus, var, XENBUS, ivar, type)
92
93 XENBUS_ACCESSOR(node, NODE, const char *)
94 XENBUS_ACCESSOR(type, TYPE, const char *)
95 XENBUS_ACCESSOR(state, STATE, enum xenbus_state)
96 XENBUS_ACCESSOR(otherend_id, OTHEREND_ID, int)
97 XENBUS_ACCESSOR(otherend_path, OTHEREND_PATH, const char *)
98
99 /**
100 * Return the state of a XenBus device.
101 *
102 * \param path The root XenStore path for the device.
103 *
104 * \return The current state of the device or XenbusStateClosed if no
105 * state can be read.
106 */
107 XenbusState xenbus_read_driver_state(const char *path);
108
109 /**
110 * Return the state of the "other end" (peer) of a XenBus device.
111 *
112 * \param dev The XenBus device whose peer to query.
113 *
114 * \return The current state of the peer device or XenbusStateClosed if no
115 * state can be read.
116 */
117 static inline XenbusState
xenbus_get_otherend_state(device_t dev)118 xenbus_get_otherend_state(device_t dev)
119 {
120 return (xenbus_read_driver_state(xenbus_get_otherend_path(dev)));
121 }
122
123 /**
124 * Grant access to the given ring_mfn to the peer of the given device.
125 *
126 * \param dev The device granting access to the ring page.
127 * \param ring_mfn The guest machine page number of the page to grant
128 * peer access rights.
129 * \param refp[out] The grant reference for the page.
130 *
131 * \return On success, 0. Otherwise an errno value indicating the
132 * type of failure.
133 *
134 * A successful call to xenbus_grant_ring should be paired with a call
135 * to gnttab_end_foreign_access() when foregn access to this page is no
136 * longer requried.
137 *
138 * \note On error, \a dev will be switched to the XenbusStateClosing
139 * state and the returned error is saved in the per-device error node
140 * for \a dev in the XenStore.
141 */
142 int xenbus_grant_ring(device_t dev, unsigned long ring_mfn, grant_ref_t *refp);
143
144 /**
145 * Record the given errno, along with the given, printf-style, formatted
146 * message in dev's device specific error node in the XenStore.
147 *
148 * \param dev The device which encountered the error.
149 * \param err The errno value corresponding to the error.
150 * \param fmt Printf format string followed by a variable number of
151 * printf arguments.
152 */
153 void xenbus_dev_error(device_t dev, int err, const char *fmt, ...)
154 __attribute__((format(printf, 3, 4)));
155
156 /**
157 * va_list version of xenbus_dev_error().
158 *
159 * \param dev The device which encountered the error.
160 * \param err The errno value corresponding to the error.
161 * \param fmt Printf format string.
162 * \param ap Va_list of printf arguments.
163 */
164 void xenbus_dev_verror(device_t dev, int err, const char *fmt, va_list ap)
165 __attribute__((format(printf, 3, 0)));
166
167 /**
168 * Equivalent to xenbus_dev_error(), followed by
169 * xenbus_set_state(dev, XenbusStateClosing).
170 *
171 * \param dev The device which encountered the error.
172 * \param err The errno value corresponding to the error.
173 * \param fmt Printf format string followed by a variable number of
174 * printf arguments.
175 */
176 void xenbus_dev_fatal(device_t dev, int err, const char *fmt, ...)
177 __attribute__((format(printf, 3, 4)));
178
179 /**
180 * va_list version of xenbus_dev_fatal().
181 *
182 * \param dev The device which encountered the error.
183 * \param err The errno value corresponding to the error.
184 * \param fmt Printf format string.
185 * \param ap Va_list of printf arguments.
186 */
187 void xenbus_dev_vfatal(device_t dev, int err, const char *fmt, va_list)
188 __attribute__((format(printf, 3, 0)));
189
190 /**
191 * Convert a member of the xenbus_state enum into an ASCII string.
192 *
193 * /param state The XenBus state to lookup.
194 *
195 * /return A string representing state or, for unrecognized states,
196 * the string "Unknown".
197 */
198 const char *xenbus_strstate(enum xenbus_state state);
199
200 /**
201 * Return the value of a XenBus device's "online" node within the XenStore.
202 *
203 * \param dev The XenBus device to query.
204 *
205 * \return The value of the "online" node for the device. If the node
206 * does not exist, 0 (offline) is returned.
207 */
208 int xenbus_dev_is_online(device_t dev);
209
210 /**
211 * Default callback invoked when a change to the local XenStore sub-tree
212 * for a device is modified.
213 *
214 * \param dev The XenBus device whose tree was modified.
215 * \param path The tree relative sub-path to the modified node. The empty
216 * string indicates the root of the tree was destroyed.
217 */
218 void xenbus_localend_changed(device_t dev, const char *path);
219
220 #include "xenbus_if.h"
221
222 #endif /* _XEN_XENBUS_XENBUSVAR_H */
223