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
32 #ifndef _XEN_XENSTORE_XENSTOREVAR_H
33 #define _XEN_XENSTORE_XENSTOREVAR_H
35 #include <sys/queue.h>
37 #include <sys/eventhandler.h>
38 #include <sys/malloc.h>
41 #include <machine/stdarg.h>
43 #include <xen/xen-os.h>
44 #include <contrib/xen/grant_table.h>
45 #include <contrib/xen/io/xenbus.h>
46 #include <contrib/xen/io/xs_wire.h>
48 #include "xenbus_if.h"
50 /* XenStore allocations including XenStore data returned to clients. */
51 MALLOC_DECLARE(M_XENSTORE);
55 typedef void (xs_watch_cb_t)(struct xs_watch *, const char **vec,
58 /* Register callback to watch subtree (node) in the XenStore. */
61 LIST_ENTRY(xs_watch) list;
63 /* Path being watched. */
66 /* Callback (executed in a process context with no locks held). */
67 xs_watch_cb_t *callback;
69 /* Callback client data untouched by the XenStore watch mechanism. */
70 uintptr_t callback_data;
72 /* Maximum number of pending watch events to be delivered. */
73 unsigned int max_pending;
76 * Private counter used by xenstore to keep track of the pending
77 * watches. Protected by xs.watch_events_lock.
81 LIST_HEAD(xs_watch_list, xs_watch);
83 typedef int (*xs_event_handler_t)(void *);
90 #define XST_NIL ((struct xs_transaction) { 0 })
93 * Check if Xenstore is initialized.
95 * \return True if initialized, false otherwise.
97 bool xs_initialized(void);
100 * Return xenstore event channel port.
102 * \return event channel port.
104 evtchn_port_t xs_evtchn(void);
107 * Return xenstore page physical memory address.
109 * \return xenstore page physical address.
111 vm_paddr_t xs_address(void);
114 * Fetch the contents of a directory in the XenStore.
116 * \param t The XenStore transaction covering this request.
117 * \param dir The dirname of the path to read.
118 * \param node The basename of the path to read.
119 * \param num The returned number of directory entries.
120 * \param result An array of directory entry strings.
122 * \return On success, 0. Otherwise an errno value indicating the
125 * \note The results buffer is malloced and should be free'd by the
126 * caller with 'free(*result, M_XENSTORE)'.
128 int xs_directory(struct xs_transaction t, const char *dir,
129 const char *node, unsigned int *num, const char ***result);
132 * Determine if a path exists in the XenStore.
134 * \param t The XenStore transaction covering this request.
135 * \param dir The dirname of the path to read.
136 * \param node The basename of the path to read.
138 * \retval 1 The path exists.
139 * \retval 0 The path does not exist or an error occurred attempting
140 * to make that determination.
142 int xs_exists(struct xs_transaction t, const char *dir, const char *node);
145 * Get the contents of a single "file". Returns the contents in
146 * *result which should be freed with free(*result, M_XENSTORE) after
147 * use. The length of the value in bytes is returned in *len.
149 * \param t The XenStore transaction covering this request.
150 * \param dir The dirname of the file to read.
151 * \param node The basename of the file to read.
152 * \param len The amount of data read.
153 * \param result The returned contents from this file.
155 * \return On success, 0. Otherwise an errno value indicating the
158 * \note The results buffer is malloced and should be free'd by the
159 * caller with 'free(*result, M_XENSTORE)'.
161 int xs_read(struct xs_transaction t, const char *dir,
162 const char *node, unsigned int *len, void **result);
165 * Write to a single file.
167 * \param t The XenStore transaction covering this request.
168 * \param dir The dirname of the file to write.
169 * \param node The basename of the file to write.
170 * \param string The NUL terminated string of data to write.
172 * \return On success, 0. Otherwise an errno value indicating the
175 int xs_write(struct xs_transaction t, const char *dir,
176 const char *node, const char *string);
179 * Create a new directory.
181 * \param t The XenStore transaction covering this request.
182 * \param dir The dirname of the directory to create.
183 * \param node The basename of the directory to create.
185 * \return On success, 0. Otherwise an errno value indicating the
188 int xs_mkdir(struct xs_transaction t, const char *dir,
192 * Remove a file or directory (directories must be empty).
194 * \param t The XenStore transaction covering this request.
195 * \param dir The dirname of the directory to remove.
196 * \param node The basename of the directory to remove.
198 * \return On success, 0. Otherwise an errno value indicating the
201 int xs_rm(struct xs_transaction t, const char *dir, const char *node);
204 * Destroy a tree of files rooted at dir/node.
206 * \param t The XenStore transaction covering this request.
207 * \param dir The dirname of the directory to remove.
208 * \param node The basename of the directory to remove.
210 * \return On success, 0. Otherwise an errno value indicating the
213 int xs_rm_tree(struct xs_transaction t, const char *dir,
217 * Start a transaction.
219 * Changes by others will not be seen during the lifetime of this
220 * transaction, and changes will not be visible to others until it
221 * is committed (xs_transaction_end).
223 * \param t The returned transaction.
225 * \return On success, 0. Otherwise an errno value indicating the
228 int xs_transaction_start(struct xs_transaction *t);
233 * \param t The transaction to end/commit.
234 * \param abort If non-zero, the transaction is discarded
235 * instead of committed.
237 * \return On success, 0. Otherwise an errno value indicating the
240 int xs_transaction_end(struct xs_transaction t, int abort);
243 * Single file read and scanf parsing of the result.
245 * \param t The XenStore transaction covering this request.
246 * \param dir The dirname of the path to read.
247 * \param node The basename of the path to read.
248 * \param scancountp The number of input values assigned (i.e. the result
250 * \param fmt Scanf format string followed by a variable number of
251 * scanf input arguments.
253 * \return On success, 0. Otherwise an errno value indicating the
256 int xs_scanf(struct xs_transaction t,
257 const char *dir, const char *node, int *scancountp, const char *fmt, ...)
258 __attribute__((format(scanf, 5, 6)));
261 * Printf formatted write to a XenStore file.
263 * \param t The XenStore transaction covering this request.
264 * \param dir The dirname of the path to read.
265 * \param node The basename of the path to read.
266 * \param fmt Printf format string followed by a variable number of
269 * \return On success, 0. Otherwise an errno value indicating the
270 * type of write failure.
272 int xs_printf(struct xs_transaction t, const char *dir,
273 const char *node, const char *fmt, ...)
274 __attribute__((format(printf, 4, 5)));
277 * va_list version of xenbus_printf().
279 * \param t The XenStore transaction covering this request.
280 * \param dir The dirname of the path to read.
281 * \param node The basename of the path to read.
282 * \param fmt Printf format string.
283 * \param ap Va_list of printf arguments.
285 * \return On success, 0. Otherwise an errno value indicating the
286 * type of write failure.
288 int xs_vprintf(struct xs_transaction t, const char *dir,
289 const char *node, const char *fmt, va_list ap);
292 * Multi-file read within a single directory and scanf parsing of
295 * \param t The XenStore transaction covering this request.
296 * \param dir The dirname of the paths to read.
297 * \param ... A variable number of argument triples specifying
298 * the file name, scanf-style format string, and
299 * output variable (pointer to storage of the results).
300 * The last triple in the call must be terminated
301 * will a final NULL argument. A NULL format string
302 * will cause the entire contents of the given file
303 * to be assigned as a NUL terminated, M_XENSTORE heap
304 * backed, string to the output parameter of that tuple.
306 * \return On success, 0. Otherwise an errno value indicating the
307 * type of read failure.
310 * char protocol_abi[64];
315 * error = xenbus_gather(XBT_NIL, xenbus_get_node(dev),
316 * "ring-ref", "%" PRIu32, &ring_ref,
317 * "protocol", "%63s", protocol_abi,
318 * "device-type", NULL, &dev_type,
323 * free(dev_type, M_XENSTORE);
325 int xs_gather(struct xs_transaction t, const char *dir, ...);
328 * Register a XenStore watch.
330 * XenStore watches allow a client to be notified via a callback (embedded
331 * within the watch object) of changes to an object in the XenStore.
333 * \param watch An xs_watch struct with it's node and callback fields
334 * properly initialized.
336 * \return On success, 0. Otherwise an errno value indicating the
337 * type of write failure. EEXIST errors from the XenStore
338 * are supressed, allowing multiple, physically different,
339 * xenbus_watch objects, to watch the same path in the XenStore.
341 int xs_register_watch(struct xs_watch *watch);
344 * Unregister a XenStore watch.
346 * \param watch An xs_watch object previously used in a successful call
347 * to xs_register_watch().
349 * The xs_watch object's node field is not altered by this call.
350 * It is the caller's responsibility to properly dispose of both the
351 * watch object and the data pointed to by watch->node.
353 void xs_unregister_watch(struct xs_watch *watch);
356 * Allocate and return an sbuf containing the XenStore path string
357 * <dir>/<name>. If name is the NUL string, the returned sbuf contains
358 * the path string <dir>.
360 * \param dir The NUL terminated directory prefix for new path.
361 * \param name The NUL terminated basename for the new path.
363 * \return A buffer containing the joined path.
365 struct sbuf *xs_join(const char *, const char *);
368 * Lock the xenstore request mutex.
373 * Unlock the xenstore request mutex.
375 void xs_unlock(void);
377 #endif /* _XEN_XENSTORE_XENSTOREVAR_H */