2 * libudev - interface to udev device information
4 * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
5 * Copyright (C) 2009 Alan Jenkins <alan-jenkins@tuffmail.co.uk>
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
25 #include "libudev-private.h"
28 * SECTION:libudev-queue
29 * @short_description: access to currently active events
31 * The udev daemon processes events asynchronously. All events which do not have
32 * interdependencies run in parallel. This exports the current state of the
33 * event processing queue, and the current event sequence numbers from the kernel
34 * and the udev daemon.
40 * Opaque object representing the current event queue in the udev daemon.
45 struct udev_list queue_list;
50 * @udev: udev library context
52 * The initial refcount is 1, and needs to be decremented to
53 * release the resources of the udev queue context.
55 * Returns: the udev queue context, or #NULL on error.
57 _public_ struct udev_queue *udev_queue_new(struct udev *udev)
59 struct udev_queue *udev_queue;
64 udev_queue = calloc(1, sizeof(struct udev_queue));
65 if (udev_queue == NULL)
67 udev_queue->refcount = 1;
68 udev_queue->udev = udev;
69 udev_list_init(udev, &udev_queue->queue_list, false);
75 * @udev_queue: udev queue context
77 * Take a reference of a udev queue context.
79 * Returns: the same udev queue context.
81 _public_ struct udev_queue *udev_queue_ref(struct udev_queue *udev_queue)
83 if (udev_queue == NULL)
85 udev_queue->refcount++;
91 * @udev_queue: udev queue context
93 * Drop a reference of a udev queue context. If the refcount reaches zero,
94 * the resources of the queue context will be released.
96 _public_ void udev_queue_unref(struct udev_queue *udev_queue)
98 if (udev_queue == NULL)
100 udev_queue->refcount--;
101 if (udev_queue->refcount > 0)
103 udev_list_cleanup(&udev_queue->queue_list);
108 * udev_queue_get_udev:
109 * @udev_queue: udev queue context
111 * Retrieve the udev library context the queue context was created with.
113 * Returns: the udev library context.
115 _public_ struct udev *udev_queue_get_udev(struct udev_queue *udev_queue)
117 if (udev_queue == NULL)
119 return udev_queue->udev;
122 unsigned long long int udev_get_kernel_seqnum(struct udev *udev)
124 unsigned long long int seqnum;
129 fd = open("/sys/kernel/uevent_seqnum", O_RDONLY|O_CLOEXEC);
132 len = read(fd, buf, sizeof(buf));
137 seqnum = strtoull(buf, NULL, 10);
142 * udev_queue_get_kernel_seqnum:
143 * @udev_queue: udev queue context
145 * Get the current kernel event sequence number.
147 * Returns: the sequence number.
149 _public_ unsigned long long int udev_queue_get_kernel_seqnum(struct udev_queue *udev_queue)
151 unsigned long long int seqnum;
153 if (udev_queue == NULL)
156 seqnum = udev_get_kernel_seqnum(udev_queue->udev);
160 int udev_queue_read_seqnum(FILE *queue_file, unsigned long long int *seqnum)
162 if (fread(seqnum, sizeof(unsigned long long int), 1, queue_file) != 1)
168 ssize_t udev_queue_skip_devpath(FILE *queue_file)
170 unsigned short int len;
172 if (fread(&len, sizeof(unsigned short int), 1, queue_file) == 1) {
173 char *devpath = alloca(len);
175 /* use fread to skip, fseek might drop buffered data */
176 if (fread(devpath, 1, len, queue_file) == len)
183 ssize_t udev_queue_read_devpath(FILE *queue_file, char *devpath, size_t size)
185 unsigned short int read_bytes = 0;
186 unsigned short int len;
188 if (fread(&len, sizeof(unsigned short int), 1, queue_file) != 1)
191 read_bytes = (len < size - 1) ? len : size - 1;
192 if (fread(devpath, 1, read_bytes, queue_file) != read_bytes)
194 devpath[read_bytes] = '\0';
196 /* if devpath was too long, skip unread characters */
197 if (read_bytes != len) {
198 unsigned short int skip_bytes = len - read_bytes;
199 char *buf = alloca(skip_bytes);
201 if (fread(buf, 1, skip_bytes, queue_file) != skip_bytes)
208 static FILE *open_queue_file(struct udev_queue *udev_queue, unsigned long long int *seqnum_start)
210 char filename[UTIL_PATH_SIZE];
213 util_strscpyl(filename, sizeof(filename), "/run/udev/queue.bin", NULL);
214 queue_file = fopen(filename, "re");
215 if (queue_file == NULL)
218 if (udev_queue_read_seqnum(queue_file, seqnum_start) < 0) {
219 err(udev_queue->udev, "corrupt queue file\n");
228 * udev_queue_get_udev_seqnum:
229 * @udev_queue: udev queue context
231 * Get the last known udev event sequence number.
233 * Returns: the sequence number.
235 _public_ unsigned long long int udev_queue_get_udev_seqnum(struct udev_queue *udev_queue)
237 unsigned long long int seqnum_udev;
240 queue_file = open_queue_file(udev_queue, &seqnum_udev);
241 if (queue_file == NULL)
245 unsigned long long int seqnum;
248 if (udev_queue_read_seqnum(queue_file, &seqnum) < 0)
250 devpath_len = udev_queue_skip_devpath(queue_file);
254 seqnum_udev = seqnum;
262 * udev_queue_get_udev_is_active:
263 * @udev_queue: udev queue context
265 * Check if udev is active on the system.
267 * Returns: a flag indicating if udev is active.
269 _public_ int udev_queue_get_udev_is_active(struct udev_queue *udev_queue)
271 unsigned long long int seqnum_start;
274 queue_file = open_queue_file(udev_queue, &seqnum_start);
275 if (queue_file == NULL)
283 * udev_queue_get_queue_is_empty:
284 * @udev_queue: udev queue context
286 * Check if udev is currently processing any events.
288 * Returns: a flag indicating if udev is currently handling events.
290 _public_ int udev_queue_get_queue_is_empty(struct udev_queue *udev_queue)
292 unsigned long long int seqnum_kernel;
293 unsigned long long int seqnum_udev = 0;
298 if (udev_queue == NULL)
300 queue_file = open_queue_file(udev_queue, &seqnum_udev);
301 if (queue_file == NULL)
305 unsigned long long int seqnum;
308 if (udev_queue_read_seqnum(queue_file, &seqnum) < 0)
310 devpath_len = udev_queue_skip_devpath(queue_file);
314 if (devpath_len > 0) {
316 seqnum_udev = seqnum;
325 seqnum_kernel = udev_queue_get_kernel_seqnum(udev_queue);
326 if (seqnum_udev < seqnum_kernel)
337 * udev_queue_get_seqnum_sequence_is_finished:
338 * @udev_queue: udev queue context
339 * @start: first event sequence number
340 * @end: last event sequence number
342 * Check if udev is currently processing any events in a given sequence number range.
344 * Returns: a flag indicating if any of the sequence numbers in the given range is currently active.
346 _public_ int udev_queue_get_seqnum_sequence_is_finished(struct udev_queue *udev_queue,
347 unsigned long long int start, unsigned long long int end)
349 unsigned long long int seqnum;
354 if (udev_queue == NULL)
356 queue_file = open_queue_file(udev_queue, &seqnum);
357 if (queue_file == NULL)
365 if (end - start > INT_MAX - 1) {
371 * we might start with 0, and handle the initial seqnum
372 * only when we find an entry in the queue file
374 unfinished = end - start;
377 if (udev_queue_read_seqnum(queue_file, &seqnum) < 0)
379 devpath_len = udev_queue_skip_devpath(queue_file);
384 * we might start with an empty or re-build queue file, where
385 * the initial seqnum is not recorded as finished
387 if (start == seqnum && devpath_len > 0)
390 if (devpath_len == 0) {
391 if (seqnum >= start && seqnum <= end)
394 } while (unfinished > 0);
398 return (unfinished == 0);
402 * udev_queue_get_seqnum_is_finished:
403 * @udev_queue: udev queue context
404 * @seqnum: sequence number
406 * Check if udev is currently processing a given sequence number.
408 * Returns: a flag indicating if the given sequence number is currently active.
410 _public_ int udev_queue_get_seqnum_is_finished(struct udev_queue *udev_queue, unsigned long long int seqnum)
412 if (!udev_queue_get_seqnum_sequence_is_finished(udev_queue, seqnum, seqnum))
419 * udev_queue_get_queued_list_entry:
420 * @udev_queue: udev queue context
422 * Get the first entry of the list of queued events.
424 * Returns: a udev_list_entry.
426 _public_ struct udev_list_entry *udev_queue_get_queued_list_entry(struct udev_queue *udev_queue)
428 unsigned long long int seqnum;
431 if (udev_queue == NULL)
433 udev_list_cleanup(&udev_queue->queue_list);
435 queue_file = open_queue_file(udev_queue, &seqnum);
436 if (queue_file == NULL)
440 char syspath[UTIL_PATH_SIZE];
445 struct udev_list_entry *list_entry;
447 if (udev_queue_read_seqnum(queue_file, &seqnum) < 0)
449 snprintf(seqnum_str, sizeof(seqnum_str), "%llu", seqnum);
452 l = util_strpcpy(&s, sizeof(syspath), "/sys");
453 len = udev_queue_read_devpath(queue_file, s, l);
458 udev_list_entry_add(&udev_queue->queue_list, syspath, seqnum_str);
460 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_queue->queue_list)) {
461 if (strcmp(seqnum_str, udev_list_entry_get_value(list_entry)) == 0) {
462 udev_list_entry_delete(list_entry);
470 return udev_list_get_entry(&udev_queue->queue_list);
473 struct udev_list_entry *udev_queue_get_failed_list_entry(struct udev_queue *udev_queue);
474 _public_ struct udev_list_entry *udev_queue_get_failed_list_entry(struct udev_queue *udev_queue)
476 err(udev_queue->udev, "udev_queue_get_failed_list_entry() does not return anything; failed events are not recorded\n");