2 * Copyright (C) 2005-2006 Kay Sievers <kay.sievers@vrfy.org>
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License as published by the
6 * Free Software Foundation version 2 of the License.
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public License along
14 * with this program; if not, write to the Free Software Foundation, Inc.,
15 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
31 char sysfs_path[PATH_SIZE];
34 static LIST_HEAD(dev_list);
36 /* attribute value cache */
37 static LIST_HEAD(attr_list);
39 struct list_head node;
41 char *value; /* points to value_local if value is cached */
42 char value_local[NAME_SIZE];
49 env = getenv("SYSFS_PATH");
51 strlcpy(sysfs_path, env, sizeof(sysfs_path));
52 remove_trailing_chars(sysfs_path, '/');
54 strlcpy(sysfs_path, "/sys", sizeof(sysfs_path));
55 dbg("sysfs_path='%s'", sysfs_path);
57 INIT_LIST_HEAD(&dev_list);
58 INIT_LIST_HEAD(&attr_list);
62 void sysfs_cleanup(void)
64 struct sysfs_attr *attr_loop;
65 struct sysfs_attr *attr_temp;
66 struct sysfs_device *dev_loop;
67 struct sysfs_device *dev_temp;
69 list_for_each_entry_safe(attr_loop, attr_temp, &attr_list, node) {
70 list_del(&attr_loop->node);
74 list_for_each_entry_safe(dev_loop, dev_temp, &dev_list, node) {
75 list_del(&dev_loop->node);
80 void sysfs_device_set_values(struct sysfs_device *dev, const char *devpath,
81 const char *subsystem, const char *driver)
85 strlcpy(dev->devpath, devpath, sizeof(dev->devpath));
86 if (subsystem != NULL)
87 strlcpy(dev->subsystem, subsystem, sizeof(dev->subsystem));
89 strlcpy(dev->driver, driver, sizeof(dev->driver));
92 pos = strrchr(dev->devpath, '/');
96 strlcpy(dev->kernel, &pos[1], sizeof(dev->kernel));
97 dbg("kernel='%s'", dev->kernel);
99 /* some devices have '!' in their name, change that to '/' */
101 while (pos[0] != '\0') {
107 /* get kernel number */
108 pos = &dev->kernel[strlen(dev->kernel)];
109 while (isdigit(pos[-1]))
111 strlcpy(dev->kernel_number, pos, sizeof(dev->kernel_number));
112 dbg("kernel_number='%s'", dev->kernel_number);
115 int sysfs_resolve_link(char *devpath, size_t size)
117 char link_path[PATH_SIZE];
118 char link_target[PATH_SIZE];
123 strlcpy(link_path, sysfs_path, sizeof(link_path));
124 strlcat(link_path, devpath, sizeof(link_path));
125 len = readlink(link_path, link_target, sizeof(link_target));
128 link_target[len] = '\0';
129 dbg("path link '%s' points to '%s'", devpath, link_target);
131 for (back = 0; strncmp(&link_target[back * 3], "../", 3) == 0; back++)
133 dbg("base '%s', tail '%s', back %i", devpath, &link_target[back * 3], back);
134 for (i = 0; i <= back; i++) {
135 char *pos = strrchr(devpath, '/');
141 dbg("after moving back '%s'", devpath);
142 strlcat(devpath, "/", size);
143 strlcat(devpath, &link_target[back * 3], size);
147 struct sysfs_device *sysfs_device_get(const char *devpath)
149 char path[PATH_SIZE];
150 char devpath_real[PATH_SIZE];
151 struct sysfs_device *dev;
152 struct sysfs_device *dev_loop;
154 char link_path[PATH_SIZE];
155 char link_target[PATH_SIZE];
159 dbg("open '%s'", devpath);
160 strlcpy(devpath_real, devpath, sizeof(devpath_real));
161 remove_trailing_chars(devpath_real, '/');
163 /* look for device already in cache (we never put an untranslated path in the cache) */
164 list_for_each_entry(dev_loop, &dev_list, node) {
165 if (strcmp(dev_loop->devpath, devpath_real) == 0) {
166 dbg("found in cache '%s'", dev_loop->devpath);
171 /* if we got a link, resolve it to the real device */
172 strlcpy(path, sysfs_path, sizeof(path));
173 strlcat(path, devpath_real, sizeof(path));
174 if (lstat(path, &statbuf) != 0) {
175 dbg("stat '%s' failed: %s", path, strerror(errno));
178 if (S_ISLNK(statbuf.st_mode)) {
179 if (sysfs_resolve_link(devpath_real, sizeof(devpath_real)) != 0)
182 /* now look for device in cache after path translation */
183 list_for_each_entry(dev_loop, &dev_list, node) {
184 if (strcmp(dev_loop->devpath, devpath_real) == 0) {
185 dbg("found in cache '%s'", dev_loop->devpath);
191 /* it is a new device */
192 dbg("new uncached device '%s'", devpath_real);
193 dev = malloc(sizeof(struct sysfs_device));
196 memset(dev, 0x00, sizeof(struct sysfs_device));
198 sysfs_device_set_values(dev, devpath_real, NULL, NULL);
201 if (strncmp(dev->devpath, "/class/", 7) == 0) {
202 strlcpy(dev->subsystem, &dev->devpath[7], sizeof(dev->subsystem));
203 pos = strchr(dev->subsystem, '/');
207 dev->subsystem[0] = '\0';
208 } else if (strncmp(dev->devpath, "/block/", 7) == 0) {
209 strlcpy(dev->subsystem, "block", sizeof(dev->subsystem));
210 } else if (strncmp(dev->devpath, "/devices/", 9) == 0) {
211 /* get subsystem from "bus" link */
212 strlcpy(link_path, sysfs_path, sizeof(link_path));
213 strlcat(link_path, dev->devpath, sizeof(link_path));
214 strlcat(link_path, "/bus", sizeof(link_path));
215 len = readlink(link_path, link_target, sizeof(link_target));
217 link_target[len] = '\0';
218 dbg("bus link '%s' points to '%s'", link_path, link_target);
219 pos = strrchr(link_target, '/');
221 strlcpy(dev->subsystem, &pos[1], sizeof(dev->subsystem));
223 /* get subsystem from "subsystem" link */
224 strlcpy(link_path, sysfs_path, sizeof(link_path));
225 strlcat(link_path, dev->devpath, sizeof(link_path));
226 strlcat(link_path, "/subsystem", sizeof(link_path));
227 len = readlink(link_path, link_target, sizeof(link_target));
229 link_target[len] = '\0';
230 dbg("subsystem link '%s' points to '%s'", link_path, link_target);
231 pos = strrchr(link_target, '/');
233 strlcpy(dev->subsystem, &pos[1], sizeof(dev->subsystem));
236 /* get driver name */
237 strlcpy(link_path, sysfs_path, sizeof(link_path));
238 strlcat(link_path, dev->devpath, sizeof(link_path));
239 strlcat(link_path, "/driver", sizeof(link_path));
240 len = readlink(link_path, link_target, sizeof(link_target));
242 link_target[len] = '\0';
243 dbg("driver link '%s' points to '%s'", link_path, link_target);
244 pos = strrchr(link_target, '/');
246 strlcpy(dev->driver, &pos[1], sizeof(dev->driver));
248 } else if (strncmp(dev->devpath, "/bus/", 5) == 0 && strstr(dev->devpath, "/drivers/")) {
249 strlcpy(dev->subsystem, "drivers", sizeof(dev->subsystem));
250 } else if (strncmp(dev->devpath, "/module/", 8) == 0) {
251 strlcpy(dev->subsystem, "module", sizeof(dev->subsystem));
254 dbg("add to cache 'devpath=%s', subsystem='%s', driver='%s'", dev->devpath, dev->subsystem, dev->driver);
255 list_add(&dev->node, &dev_list);
260 struct sysfs_device *sysfs_device_get_parent(struct sysfs_device *dev)
262 char parent_devpath[PATH_SIZE];
265 dbg("open '%s'", dev->devpath);
267 /* look if we already know the parent */
268 if (dev->parent != NULL)
271 /* requesting a parent is only valid for devices */
272 if ((strncmp(dev->devpath, "/devices/", 9) != 0) &&
273 (strncmp(dev->devpath, "/class/", 7) != 0) &&
274 (strncmp(dev->devpath, "/block/", 7) != 0))
277 strlcpy(parent_devpath, dev->devpath, sizeof(parent_devpath));
278 dbg("'%s'", parent_devpath);
280 /* strip last element */
281 pos = strrchr(parent_devpath, '/');
282 if (pos == NULL || pos == parent_devpath)
286 /* are we at the top level of /devices */
287 if (strcmp(parent_devpath, "/devices") == 0) {
288 dbg("/devices top level");
292 /* at the top level of class/block we want to follow the "device" link */
293 if (strcmp(parent_devpath, "/block") == 0) {
294 dbg("/block top level, look for device link");
297 if (strncmp(parent_devpath, "/class", 6) == 0) {
298 pos = strrchr(parent_devpath, '/');
299 if (pos == &parent_devpath[6] || pos == parent_devpath) {
300 dbg("/class top level, look for device link");
304 /* get parent and remember it */
305 dev->parent = sysfs_device_get(parent_devpath);
309 strlcpy(parent_devpath, dev->devpath, sizeof(parent_devpath));
310 strlcat(parent_devpath, "/device", sizeof(parent_devpath));
311 if (sysfs_resolve_link(parent_devpath, sizeof(parent_devpath)) != 0)
314 /* get parent and remember it */
315 dev->parent = sysfs_device_get(parent_devpath);
319 struct sysfs_device *sysfs_device_get_parent_with_subsystem(struct sysfs_device *dev, const char *subsystem)
321 struct sysfs_device *dev_parent;
323 dev_parent = sysfs_device_get_parent(dev);
324 while (dev_parent != NULL) {
325 if (strcmp(dev_parent->subsystem, subsystem) == 0)
327 dev_parent = sysfs_device_get_parent(dev_parent);
332 char *sysfs_attr_get_value(const char *devpath, const char *attr_name)
334 char path_full[PATH_SIZE];
336 char value[NAME_SIZE];
337 struct sysfs_attr *attr_loop;
338 struct sysfs_attr *attr;
344 dbg("open '%s'/'%s'", devpath, attr_name);
345 sysfs_len = strlcpy(path_full, sysfs_path, sizeof(path_full));
346 path = &path_full[sysfs_len];
347 strlcat(path_full, devpath, sizeof(path_full));
348 strlcat(path_full, "/", sizeof(path_full));
349 strlcat(path_full, attr_name, sizeof(path_full));
351 /* look for attribute in cache */
352 list_for_each_entry(attr_loop, &attr_list, node) {
353 if (strcmp(attr_loop->path, path) == 0) {
354 dbg("found in cache '%s'", attr_loop->path);
355 return attr_loop->value;
359 /* store attribute in cache (also negatives are kept in cache) */
360 dbg("new uncached attribute '%s'", path_full);
361 attr = malloc(sizeof(struct sysfs_attr));
364 memset(attr, 0x00, sizeof(struct sysfs_attr));
365 strlcpy(attr->path, path, sizeof(attr->path));
366 dbg("add to cache '%s'", path_full);
367 list_add(&attr->node, &attr_list);
369 if (lstat(path_full, &statbuf) != 0) {
370 dbg("stat '%s' failed: %s", path_full, strerror(errno));
374 if (S_ISLNK(statbuf.st_mode)) {
375 /* links return the last element of the target path */
376 char link_target[PATH_SIZE];
380 len = readlink(path_full, link_target, sizeof(link_target));
382 link_target[len] = '\0';
383 pos = strrchr(link_target, '/');
385 dbg("cache '%s' with link value '%s'", path_full, value);
386 strlcpy(attr->value_local, &pos[1], sizeof(attr->value_local));
387 attr->value = attr->value_local;
393 /* skip directories */
394 if (S_ISDIR(statbuf.st_mode))
397 /* skip non-readable files */
398 if ((statbuf.st_mode & S_IRUSR) == 0)
401 /* read attribute value */
402 fd = open(path_full, O_RDONLY);
404 dbg("attribute '%s' does not exist", path_full);
407 size = read(fd, value, sizeof(value));
411 if (size == sizeof(value))
414 /* got a valid value, store and return it */
416 remove_trailing_chars(value, '\n');
417 dbg("cache '%s' with attribute value '%s'", path_full, value);
418 strlcpy(attr->value_local, value, sizeof(attr->value_local));
419 attr->value = attr->value_local;