1 /******************************************************************************
4 * Method declarations and structures for accessing the XenStore.h
6 * Copyright (C) 2005 Rusty Russell, IBM Corporation
7 * Copyright (C) 2005 XenSource Ltd.
8 * Copyright (C) 2009,2010 Spectra Logic Corporation
10 * This file may be distributed separately from the Linux kernel, or
11 * incorporated into other software packages, subject to the following license:
13 * Permission is hereby granted, free of charge, to any person obtaining a copy
14 * of this source file (the "Software"), to deal in the Software without
15 * restriction, including without limitation the rights to use, copy, modify,
16 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
17 * and to permit persons to whom the Software is furnished to do so, subject to
18 * the following conditions:
20 * The above copyright notice and this permission notice shall be included in
21 * all copies or substantial portions of the Software.
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
24 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
25 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
26 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
27 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
28 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
34 #ifndef _XEN_XENSTORE_XENSTOREVAR_H
35 #define _XEN_XENSTORE_XENSTOREVAR_H
37 #include <sys/queue.h>
39 #include <sys/eventhandler.h>
40 #include <sys/malloc.h>
43 #include <machine/stdarg.h>
45 #include <xen/xen-os.h>
46 #include <xen/interface/grant_table.h>
47 #include <xen/interface/io/xenbus.h>
48 #include <xen/interface/io/xs_wire.h>
50 #include "xenbus_if.h"
52 /* XenStore allocations including XenStore data returned to clients. */
53 MALLOC_DECLARE(M_XENSTORE);
57 typedef void (xs_watch_cb_t)(struct xs_watch *, const char **vec,
60 /* Register callback to watch subtree (node) in the XenStore. */
63 LIST_ENTRY(xs_watch) list;
65 /* Path being watched. */
68 /* Callback (executed in a process context with no locks held). */
69 xs_watch_cb_t *callback;
71 /* Callback client data untouched by the XenStore watch mechanism. */
72 uintptr_t callback_data;
74 /* Maximum number of pending watch events to be delivered. */
75 unsigned int max_pending;
78 * Private counter used by xenstore to keep track of the pending
79 * watches. Protected by xs.watch_events_lock.
83 LIST_HEAD(xs_watch_list, xs_watch);
85 typedef int (*xs_event_handler_t)(void *);
92 #define XST_NIL ((struct xs_transaction) { 0 })
95 * Check if Xenstore is initialized.
97 * \return True if initialized, false otherwise.
99 bool xs_initialized(void);
102 * Return xenstore event channel port.
104 * \return event channel port.
106 evtchn_port_t xs_evtchn(void);
109 * Return xenstore page physical memory address.
111 * \return xenstore page physical address.
113 vm_paddr_t xs_address(void);
116 * Fetch the contents of a directory in the XenStore.
118 * \param t The XenStore transaction covering this request.
119 * \param dir The dirname of the path to read.
120 * \param node The basename of the path to read.
121 * \param num The returned number of directory entries.
122 * \param result An array of directory entry strings.
124 * \return On success, 0. Otherwise an errno value indicating the
127 * \note The results buffer is malloced and should be free'd by the
128 * caller with 'free(*result, M_XENSTORE)'.
130 int xs_directory(struct xs_transaction t, const char *dir,
131 const char *node, unsigned int *num, const char ***result);
134 * Determine if a path exists in the XenStore.
136 * \param t The XenStore transaction covering this request.
137 * \param dir The dirname of the path to read.
138 * \param node The basename of the path to read.
140 * \retval 1 The path exists.
141 * \retval 0 The path does not exist or an error occurred attempting
142 * to make that determination.
144 int xs_exists(struct xs_transaction t, const char *dir, const char *node);
147 * Get the contents of a single "file". Returns the contents in
148 * *result which should be freed with free(*result, M_XENSTORE) after
149 * use. The length of the value in bytes is returned in *len.
151 * \param t The XenStore transaction covering this request.
152 * \param dir The dirname of the file to read.
153 * \param node The basename of the file to read.
154 * \param len The amount of data read.
155 * \param result The returned contents from this file.
157 * \return On success, 0. Otherwise an errno value indicating the
160 * \note The results buffer is malloced and should be free'd by the
161 * caller with 'free(*result, M_XENSTORE)'.
163 int xs_read(struct xs_transaction t, const char *dir,
164 const char *node, unsigned int *len, void **result);
167 * Write to a single file.
169 * \param t The XenStore transaction covering this request.
170 * \param dir The dirname of the file to write.
171 * \param node The basename of the file to write.
172 * \param string The NUL terminated string of data to write.
174 * \return On success, 0. Otherwise an errno value indicating the
177 int xs_write(struct xs_transaction t, const char *dir,
178 const char *node, const char *string);
181 * Create a new directory.
183 * \param t The XenStore transaction covering this request.
184 * \param dir The dirname of the directory to create.
185 * \param node The basename of the directory to create.
187 * \return On success, 0. Otherwise an errno value indicating the
190 int xs_mkdir(struct xs_transaction t, const char *dir,
194 * Remove a file or directory (directories must be empty).
196 * \param t The XenStore transaction covering this request.
197 * \param dir The dirname of the directory to remove.
198 * \param node The basename of the directory to remove.
200 * \return On success, 0. Otherwise an errno value indicating the
203 int xs_rm(struct xs_transaction t, const char *dir, const char *node);
206 * Destroy a tree of files rooted at dir/node.
208 * \param t The XenStore transaction covering this request.
209 * \param dir The dirname of the directory to remove.
210 * \param node The basename of the directory to remove.
212 * \return On success, 0. Otherwise an errno value indicating the
215 int xs_rm_tree(struct xs_transaction t, const char *dir,
219 * Start a transaction.
221 * Changes by others will not be seen during the lifetime of this
222 * transaction, and changes will not be visible to others until it
223 * is committed (xs_transaction_end).
225 * \param t The returned transaction.
227 * \return On success, 0. Otherwise an errno value indicating the
230 int xs_transaction_start(struct xs_transaction *t);
235 * \param t The transaction to end/commit.
236 * \param abort If non-zero, the transaction is discarded
237 * instead of committed.
239 * \return On success, 0. Otherwise an errno value indicating the
242 int xs_transaction_end(struct xs_transaction t, int abort);
245 * Single file read and scanf parsing of the result.
247 * \param t The XenStore transaction covering this request.
248 * \param dir The dirname of the path to read.
249 * \param node The basename of the path to read.
250 * \param scancountp The number of input values assigned (i.e. the result
252 * \param fmt Scanf format string followed by a variable number of
253 * scanf input arguments.
255 * \return On success, 0. Otherwise an errno value indicating the
258 int xs_scanf(struct xs_transaction t,
259 const char *dir, const char *node, int *scancountp, const char *fmt, ...)
260 __attribute__((format(scanf, 5, 6)));
263 * Printf formatted write to a XenStore file.
265 * \param t The XenStore transaction covering this request.
266 * \param dir The dirname of the path to read.
267 * \param node The basename of the path to read.
268 * \param fmt Printf format string followed by a variable number of
271 * \return On success, 0. Otherwise an errno value indicating the
272 * type of write failure.
274 int xs_printf(struct xs_transaction t, const char *dir,
275 const char *node, const char *fmt, ...)
276 __attribute__((format(printf, 4, 5)));
279 * va_list version of xenbus_printf().
281 * \param t The XenStore transaction covering this request.
282 * \param dir The dirname of the path to read.
283 * \param node The basename of the path to read.
284 * \param fmt Printf format string.
285 * \param ap Va_list of printf arguments.
287 * \return On success, 0. Otherwise an errno value indicating the
288 * type of write failure.
290 int xs_vprintf(struct xs_transaction t, const char *dir,
291 const char *node, const char *fmt, va_list ap);
294 * Multi-file read within a single directory and scanf parsing of
297 * \param t The XenStore transaction covering this request.
298 * \param dir The dirname of the paths to read.
299 * \param ... A variable number of argument triples specifying
300 * the file name, scanf-style format string, and
301 * output variable (pointer to storage of the results).
302 * The last triple in the call must be terminated
303 * will a final NULL argument. A NULL format string
304 * will cause the entire contents of the given file
305 * to be assigned as a NUL terminated, M_XENSTORE heap
306 * backed, string to the output parameter of that tuple.
308 * \return On success, 0. Otherwise an errno value indicating the
309 * type of read failure.
312 * char protocol_abi[64];
317 * error = xenbus_gather(XBT_NIL, xenbus_get_node(dev),
318 * "ring-ref", "%" PRIu32, &ring_ref,
319 * "protocol", "%63s", protocol_abi,
320 * "device-type", NULL, &dev_type,
325 * free(dev_type, M_XENSTORE);
327 int xs_gather(struct xs_transaction t, const char *dir, ...);
330 * Register a XenStore watch.
332 * XenStore watches allow a client to be notified via a callback (embedded
333 * within the watch object) of changes to an object in the XenStore.
335 * \param watch An xs_watch struct with it's node and callback fields
336 * properly initialized.
338 * \return On success, 0. Otherwise an errno value indicating the
339 * type of write failure. EEXIST errors from the XenStore
340 * are supressed, allowing multiple, physically different,
341 * xenbus_watch objects, to watch the same path in the XenStore.
343 int xs_register_watch(struct xs_watch *watch);
346 * Unregister a XenStore watch.
348 * \param watch An xs_watch object previously used in a successful call
349 * to xs_register_watch().
351 * The xs_watch object's node field is not altered by this call.
352 * It is the caller's responsibility to properly dispose of both the
353 * watch object and the data pointed to by watch->node.
355 void xs_unregister_watch(struct xs_watch *watch);
358 * Allocate and return an sbuf containing the XenStore path string
359 * <dir>/<name>. If name is the NUL string, the returned sbuf contains
360 * the path string <dir>.
362 * \param dir The NUL terminated directory prefix for new path.
363 * \param name The NUL terminated basename for the new path.
365 * \return A buffer containing the joined path.
367 struct sbuf *xs_join(const char *, const char *);
370 * Lock the xenstore request mutex.
375 * Unlock the xenstore request mutex.
377 void xs_unlock(void);
379 #endif /* _XEN_XENSTORE_XENSTOREVAR_H */