1/* 2 * Copyright (C) 2005-2006 Kay Sievers <kay.sievers@vrfy.org> 3 * 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. 7 * 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. 12 * 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. 16 * 17 */ 18 19 20#include <stdlib.h> 21#include <stdio.h> 22#include <stddef.h> 23#include <unistd.h> 24#include <fcntl.h> 25#include <ctype.h> 26#include <errno.h> 27#include <sys/stat.h> 28 29#include "udev.h" 30 31char sysfs_path[PATH_SIZE]; 32 33/* device cache */ 34static LIST_HEAD(dev_list); 35 36/* attribute value cache */ 37static LIST_HEAD(attr_list); 38struct sysfs_attr { 39 struct list_head node; 40 char path[PATH_SIZE]; 41 char *value; /* points to value_local if value is cached */ 42 char value_local[NAME_SIZE]; 43}; 44 45int sysfs_init(void) 46{ 47 const char *env; 48 49 env = getenv("SYSFS_PATH"); 50 if (env) { 51 strlcpy(sysfs_path, env, sizeof(sysfs_path)); 52 remove_trailing_chars(sysfs_path, '/'); 53 } else 54 strlcpy(sysfs_path, "/sys", sizeof(sysfs_path)); 55 dbg("sysfs_path='%s'", sysfs_path); 56 57 INIT_LIST_HEAD(&dev_list); 58 INIT_LIST_HEAD(&attr_list); 59 return 0; 60} 61 62void sysfs_cleanup(void) 63{ 64 struct sysfs_attr *attr_loop; 65 struct sysfs_attr *attr_temp; 66 struct sysfs_device *dev_loop; 67 struct sysfs_device *dev_temp; 68 69 list_for_each_entry_safe(attr_loop, attr_temp, &attr_list, node) { 70 list_del(&attr_loop->node); 71 free(attr_loop); 72 } 73 74 list_for_each_entry_safe(dev_loop, dev_temp, &dev_list, node) { 75 list_del(&dev_loop->node); 76 free(dev_loop); 77 } 78} 79 80void sysfs_device_set_values(struct sysfs_device *dev, const char *devpath, 81 const char *subsystem, const char *driver) 82{ 83 char *pos; 84 85 strlcpy(dev->devpath, devpath, sizeof(dev->devpath)); 86 if (subsystem != NULL) 87 strlcpy(dev->subsystem, subsystem, sizeof(dev->subsystem)); 88 if (driver != NULL) 89 strlcpy(dev->driver, driver, sizeof(dev->driver)); 90 91 /* set kernel name */ 92 pos = strrchr(dev->devpath, '/'); 93 if (pos == NULL) 94 return; 95 strlcpy(dev->kernel, &pos[1], sizeof(dev->kernel)); 96 dbg("kernel='%s'", dev->kernel); 97 98 /* some devices have '!' in their name, change that to '/' */ 99 pos = dev->kernel; 100 while (pos[0] != '\0') { 101 if (pos[0] == '!') 102 pos[0] = '/'; 103 pos++; 104 } 105 106 /* get kernel number */ 107 pos = &dev->kernel[strlen(dev->kernel)]; 108 while (isdigit(pos[-1])) 109 pos--; 110 strlcpy(dev->kernel_number, pos, sizeof(dev->kernel_number)); 111 dbg("kernel_number='%s'", dev->kernel_number); 112} 113 114int sysfs_resolve_link(char *devpath, size_t size) 115{ 116 char link_path[PATH_SIZE]; 117 char link_target[PATH_SIZE]; 118 int len; 119 int i; 120 int back; 121 122 strlcpy(link_path, sysfs_path, sizeof(link_path)); 123 strlcat(link_path, devpath, sizeof(link_path)); 124 len = readlink(link_path, link_target, sizeof(link_target)); 125 if (len <= 0) 126 return -1; 127 link_target[len] = '\0'; 128 dbg("path link '%s' points to '%s'", devpath, link_target); 129 130 for (back = 0; strncmp(&link_target[back * 3], "../", 3) == 0; back++) 131 ; 132 dbg("base '%s', tail '%s', back %i", devpath, &link_target[back * 3], back); 133 for (i = 0; i <= back; i++) { 134 char *pos = strrchr(devpath, '/'); 135 136 if (pos == NULL) 137 return -1; 138 pos[0] = '\0'; 139 } 140 dbg("after moving back '%s'", devpath); 141 strlcat(devpath, "/", size); 142 strlcat(devpath, &link_target[back * 3], size); 143 return 0; 144} 145 146struct sysfs_device *sysfs_device_get(const char *devpath) 147{ 148 char path[PATH_SIZE]; 149 char devpath_real[PATH_SIZE]; 150 struct sysfs_device *dev; 151 struct sysfs_device *dev_loop; 152 struct stat statbuf; 153 char link_path[PATH_SIZE]; 154 char link_target[PATH_SIZE]; 155 int len; 156 char *pos; 157 158 /* we handle only these devpathes */ 159 if (devpath != NULL && 160 strncmp(devpath, "/devices/", 9) != 0 && 161 strncmp(devpath, "/subsystem/", 11) != 0 && 162 strncmp(devpath, "/module/", 8) != 0 && 163 strncmp(devpath, "/bus/", 5) != 0 && 164 strncmp(devpath, "/class/", 7) != 0 && 165 strncmp(devpath, "/block/", 7) != 0) 166 return NULL; 167 168 dbg("open '%s'", devpath); 169 strlcpy(devpath_real, devpath, sizeof(devpath_real)); 170 remove_trailing_chars(devpath_real, '/'); 171 if (devpath[0] == '\0' ) 172 return NULL; 173 174 /* look for device already in cache (we never put an untranslated path in the cache) */ 175 list_for_each_entry(dev_loop, &dev_list, node) { 176 if (strcmp(dev_loop->devpath, devpath_real) == 0) { 177 dbg("found in cache '%s'", dev_loop->devpath); 178 return dev_loop; 179 } 180 } 181 182 /* if we got a link, resolve it to the real device */ 183 strlcpy(path, sysfs_path, sizeof(path)); 184 strlcat(path, devpath_real, sizeof(path)); 185 if (lstat(path, &statbuf) != 0) { 186 dbg("stat '%s' failed: %s", path, strerror(errno)); 187 return NULL; 188 } 189 if (S_ISLNK(statbuf.st_mode)) { 190 if (sysfs_resolve_link(devpath_real, sizeof(devpath_real)) != 0) 191 return NULL; 192 193 /* now look for device in cache after path translation */ 194 list_for_each_entry(dev_loop, &dev_list, node) { 195 if (strcmp(dev_loop->devpath, devpath_real) == 0) { 196 dbg("found in cache '%s'", dev_loop->devpath); 197 return dev_loop; 198 } 199 } 200 } 201 202 /* it is a new device */ 203 dbg("new uncached device '%s'", devpath_real); 204 dev = malloc(sizeof(struct sysfs_device)); 205 if (dev == NULL) 206 return NULL; 207 memset(dev, 0x00, sizeof(struct sysfs_device)); 208 209 sysfs_device_set_values(dev, devpath_real, NULL, NULL); 210 211 /* get subsystem name */ 212 strlcpy(link_path, sysfs_path, sizeof(link_path)); 213 strlcat(link_path, dev->devpath, sizeof(link_path)); 214 strlcat(link_path, "/subsystem", sizeof(link_path)); 215 len = readlink(link_path, link_target, sizeof(link_target)); 216 if (len > 0) { 217 /* get subsystem from "subsystem" link */ 218 link_target[len] = '\0'; 219 dbg("subsystem link '%s' points to '%s'", link_path, link_target); 220 pos = strrchr(link_target, '/'); 221 if (pos != NULL) 222 strlcpy(dev->subsystem, &pos[1], sizeof(dev->subsystem)); 223 } else if (strncmp(dev->devpath, "/class/", 7) == 0) { 224 /* get subsystem from class dir */ 225 strlcpy(dev->subsystem, &dev->devpath[7], sizeof(dev->subsystem)); 226 pos = strchr(dev->subsystem, '/'); 227 if (pos != NULL) 228 pos[0] = '\0'; 229 else 230 strlcpy(dev->subsystem, "subsystem", sizeof(dev->subsystem)); 231 } else if (strncmp(dev->devpath, "/block/", 7) == 0) { 232 strlcpy(dev->subsystem, "block", sizeof(dev->subsystem)); 233 } else if (strncmp(dev->devpath, "/devices/", 9) == 0) { 234 /* get subsystem from "bus" link */ 235 strlcpy(link_path, sysfs_path, sizeof(link_path)); 236 strlcat(link_path, dev->devpath, sizeof(link_path)); 237 strlcat(link_path, "/bus", sizeof(link_path)); 238 len = readlink(link_path, link_target, sizeof(link_target)); 239 if (len > 0) { 240 link_target[len] = '\0'; 241 dbg("bus link '%s' points to '%s'", link_path, link_target); 242 pos = strrchr(link_target, '/'); 243 if (pos != NULL) 244 strlcpy(dev->subsystem, &pos[1], sizeof(dev->subsystem)); 245 } 246 } else if (strstr(dev->devpath, "/drivers/") != NULL) { 247 strlcpy(dev->subsystem, "drivers", sizeof(dev->subsystem)); 248 } else if (strncmp(dev->devpath, "/module/", 8) == 0) { 249 strlcpy(dev->subsystem, "module", sizeof(dev->subsystem)); 250 } else if (strncmp(dev->devpath, "/subsystem/", 11) == 0) { 251 pos = strrchr(dev->devpath, '/'); 252 if (pos == &dev->devpath[10]) 253 strlcpy(dev->subsystem, "subsystem", sizeof(dev->subsystem)); 254 } else if (strncmp(dev->devpath, "/bus/", 5) == 0) { 255 pos = strrchr(dev->devpath, '/'); 256 if (pos == &dev->devpath[4]) 257 strlcpy(dev->subsystem, "subsystem", sizeof(dev->subsystem)); 258 } 259 260 /* get driver name */ 261 strlcpy(link_path, sysfs_path, sizeof(link_path)); 262 strlcat(link_path, dev->devpath, sizeof(link_path)); 263 strlcat(link_path, "/driver", sizeof(link_path)); 264 len = readlink(link_path, link_target, sizeof(link_target)); 265 if (len > 0) { 266 link_target[len] = '\0'; 267 dbg("driver link '%s' points to '%s'", link_path, link_target); 268 pos = strrchr(link_target, '/'); 269 if (pos != NULL) 270 strlcpy(dev->driver, &pos[1], sizeof(dev->driver)); 271 } 272 273 dbg("add to cache 'devpath=%s', subsystem='%s', driver='%s'", dev->devpath, dev->subsystem, dev->driver); 274 list_add(&dev->node, &dev_list); 275 276 return dev; 277} 278 279struct sysfs_device *sysfs_device_get_parent(struct sysfs_device *dev) 280{ 281 char parent_devpath[PATH_SIZE]; 282 char *pos; 283 284 dbg("open '%s'", dev->devpath); 285 286 /* look if we already know the parent */ 287 if (dev->parent != NULL) 288 return dev->parent; 289 290 strlcpy(parent_devpath, dev->devpath, sizeof(parent_devpath)); 291 dbg("'%s'", parent_devpath); 292 293 /* strip last element */ 294 pos = strrchr(parent_devpath, '/'); 295 if (pos == NULL || pos == parent_devpath) 296 return NULL; 297 pos[0] = '\0'; 298 299 if (strncmp(parent_devpath, "/class", 6) == 0) { 300 pos = strrchr(parent_devpath, '/'); 301 if (pos == &parent_devpath[6] || pos == parent_devpath) { 302 dbg("/class top level, look for device link"); 303 goto device_link; 304 } 305 } 306 if (strcmp(parent_devpath, "/block") == 0) { 307 dbg("/block top level, look for device link"); 308 goto device_link; 309 } 310 311 /* are we at the top level? */ 312 pos = strrchr(parent_devpath, '/'); 313 if (pos == NULL || pos == parent_devpath) 314 return NULL; 315 316 /* get parent and remember it */ 317 dev->parent = sysfs_device_get(parent_devpath); 318 return dev->parent; 319 320device_link: 321 strlcpy(parent_devpath, dev->devpath, sizeof(parent_devpath)); 322 strlcat(parent_devpath, "/device", sizeof(parent_devpath)); 323 if (sysfs_resolve_link(parent_devpath, sizeof(parent_devpath)) != 0) 324 return NULL; 325 326 /* get parent and remember it */ 327 dev->parent = sysfs_device_get(parent_devpath); 328 return dev->parent; 329} 330 331struct sysfs_device *sysfs_device_get_parent_with_subsystem(struct sysfs_device *dev, const char *subsystem) 332{ 333 struct sysfs_device *dev_parent; 334 335 dev_parent = sysfs_device_get_parent(dev); 336 while (dev_parent != NULL) { 337 if (strcmp(dev_parent->subsystem, subsystem) == 0) 338 return dev_parent; 339 dev_parent = sysfs_device_get_parent(dev_parent); 340 } 341 return NULL; 342} 343 344char *sysfs_attr_get_value(const char *devpath, const char *attr_name) 345{ 346 char path_full[PATH_SIZE]; 347 const char *path; 348 char value[NAME_SIZE]; 349 struct sysfs_attr *attr_loop; 350 struct sysfs_attr *attr; 351 struct stat statbuf; 352 int fd; 353 ssize_t size; 354 size_t sysfs_len; 355 356 dbg("open '%s'/'%s'", devpath, attr_name); 357 sysfs_len = strlcpy(path_full, sysfs_path, sizeof(path_full)); 358 path = &path_full[sysfs_len]; 359 strlcat(path_full, devpath, sizeof(path_full)); 360 strlcat(path_full, "/", sizeof(path_full)); 361 strlcat(path_full, attr_name, sizeof(path_full)); 362 363 /* look for attribute in cache */ 364 list_for_each_entry(attr_loop, &attr_list, node) { 365 if (strcmp(attr_loop->path, path) == 0) { 366 dbg("found in cache '%s'", attr_loop->path); 367 return attr_loop->value; 368 } 369 } 370 371 /* store attribute in cache (also negatives are kept in cache) */ 372 dbg("new uncached attribute '%s'", path_full); 373 attr = malloc(sizeof(struct sysfs_attr)); 374 if (attr == NULL) 375 return NULL; 376 memset(attr, 0x00, sizeof(struct sysfs_attr)); 377 strlcpy(attr->path, path, sizeof(attr->path)); 378 dbg("add to cache '%s'", path_full); 379 list_add(&attr->node, &attr_list); 380 381 if (lstat(path_full, &statbuf) != 0) { 382 dbg("stat '%s' failed: %s", path_full, strerror(errno)); 383 goto out; 384 } 385 386 if (S_ISLNK(statbuf.st_mode)) { 387 /* links return the last element of the target path */ 388 char link_target[PATH_SIZE]; 389 int len; 390 const char *pos; 391 392 len = readlink(path_full, link_target, sizeof(link_target)); 393 if (len > 0) { 394 link_target[len] = '\0'; 395 pos = strrchr(link_target, '/'); 396 if (pos != NULL) { 397 dbg("cache '%s' with link value '%s'", path_full, value); 398 strlcpy(attr->value_local, &pos[1], sizeof(attr->value_local)); 399 attr->value = attr->value_local; 400 } 401 } 402 goto out; 403 } 404 405 /* skip directories */ 406 if (S_ISDIR(statbuf.st_mode)) 407 goto out; 408 409 /* skip non-readable files */ 410 if ((statbuf.st_mode & S_IRUSR) == 0) 411 goto out; 412 413 /* read attribute value */ 414 fd = open(path_full, O_RDONLY); 415 if (fd < 0) { 416 dbg("attribute '%s' does not exist", path_full); 417 goto out; 418 } 419 size = read(fd, value, sizeof(value)); 420 close(fd); 421 if (size < 0) 422 goto out; 423 if (size == sizeof(value)) 424 goto out; 425 426 /* got a valid value, store and return it */ 427 value[size] = '\0'; 428 remove_trailing_chars(value, '\n'); 429 dbg("cache '%s' with attribute value '%s'", path_full, value); 430 strlcpy(attr->value_local, value, sizeof(attr->value_local)); 431 attr->value = attr->value_local; 432 433out: 434 return attr->value; 435} 436 437int sysfs_lookup_devpath_by_subsys_id(char *devpath_full, size_t len, const char *subsystem, const char *id) 438{ 439 size_t sysfs_len; 440 char path_full[PATH_SIZE]; 441 char *path; 442 struct stat statbuf; 443 444 sysfs_len = strlcpy(path_full, sysfs_path, sizeof(path_full)); 445 path = &path_full[sysfs_len]; 446 447 if (strcmp(subsystem, "subsystem") == 0) { 448 strlcpy(path, "/subsystem/", sizeof(path_full) - sysfs_len); 449 strlcat(path, id, sizeof(path_full) - sysfs_len); 450 if (stat(path_full, &statbuf) == 0) 451 goto found; 452 453 strlcpy(path, "/bus/", sizeof(path_full) - sysfs_len); 454 strlcat(path, id, sizeof(path_full) - sysfs_len); 455 if (stat(path_full, &statbuf) == 0) 456 goto found; 457 goto out; 458 459 strlcpy(path, "/class/", sizeof(path_full) - sysfs_len); 460 strlcat(path, id, sizeof(path_full) - sysfs_len); 461 if (stat(path_full, &statbuf) == 0) 462 goto found; 463 } 464 465 if (strcmp(subsystem, "module") == 0) { 466 strlcpy(path, "/module/", sizeof(path_full) - sysfs_len); 467 strlcat(path, id, sizeof(path_full) - sysfs_len); 468 if (stat(path_full, &statbuf) == 0) 469 goto found; 470 goto out; 471 } 472 473 if (strcmp(subsystem, "drivers") == 0) { 474 char subsys[NAME_SIZE]; 475 char *driver; 476 477 strlcpy(subsys, id, sizeof(subsys)); 478 driver = strchr(subsys, ':'); 479 if (driver != NULL) { 480 driver[0] = '\0'; 481 driver = &driver[1]; 482 strlcpy(path, "/subsystem/", sizeof(path_full) - sysfs_len); 483 strlcat(path, subsys, sizeof(path_full) - sysfs_len); 484 strlcat(path, "/drivers/", sizeof(path_full) - sysfs_len); 485 strlcat(path, driver, sizeof(path_full) - sysfs_len); 486 if (stat(path_full, &statbuf) == 0) 487 goto found; 488 489 strlcpy(path, "/bus/", sizeof(path_full) - sysfs_len); 490 strlcat(path, subsys, sizeof(path_full) - sysfs_len); 491 strlcat(path, "/drivers/", sizeof(path_full) - sysfs_len); 492 strlcat(path, driver, sizeof(path_full) - sysfs_len); 493 if (stat(path_full, &statbuf) == 0) 494 goto found; 495 } 496 goto out; 497 } 498 499 strlcpy(path, "/subsystem/", sizeof(path_full) - sysfs_len); 500 strlcat(path, subsystem, sizeof(path_full) - sysfs_len); 501 strlcat(path, "/devices/", sizeof(path_full) - sysfs_len); 502 strlcat(path, id, sizeof(path_full) - sysfs_len); 503 if (stat(path_full, &statbuf) == 0) 504 goto found; 505 506 strlcpy(path, "/bus/", sizeof(path_full) - sysfs_len); 507 strlcat(path, subsystem, sizeof(path_full) - sysfs_len); 508 strlcat(path, "/devices/", sizeof(path_full) - sysfs_len); 509 strlcat(path, id, sizeof(path_full) - sysfs_len); 510 if (stat(path_full, &statbuf) == 0) 511 goto found; 512 513 strlcpy(path, "/class/", sizeof(path_full) - sysfs_len); 514 strlcat(path, subsystem, sizeof(path_full) - sysfs_len); 515 strlcat(path, "/", sizeof(path_full) - sysfs_len); 516 strlcat(path, id, sizeof(path_full) - sysfs_len); 517 if (stat(path_full, &statbuf) == 0) 518 goto found; 519out: 520 return 0; 521found: 522 if (S_ISLNK(statbuf.st_mode)) 523 sysfs_resolve_link(path, sizeof(path_full) - sysfs_len); 524 strlcpy(devpath_full, path, len); 525 return 1; 526} 527